Boiler & Auxiliaries Maintenance Manuall Qn1 Sec g 04 Tp 009

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QUANG NINH THERMAL POWER JOINT STOCK COMPANY 2×300 MW

BOILER & AUXILIARIES MAINTENANCE MANUAL

Date: 2008-10-20 No.:QN1-SEC-G-04-TP-009 Rev. : A

QUANG NINH THERMAL POWER JOINT STOCK COMPANY

2 × 300 MW – Anthracite Coal Fired Power Station

BOILER & AUXILIARIES 、

Maintenance Manual

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Date: 2008-10-20 No.:QN1-SEC-G-04-TP-009 - 1 - Rev. : A

INDEX

1 MAIN TECHNICAL SPECIFICATIONS AND STRUCTURE OF BOILER ( TAKING SG-995/17.3-MMX BOILER AS EXAMPLE)................................................................................................- 1 -

1.1 GENERAL ................................................................................................................................................... - 1 - 1.2 TECHNICAL SPECIFICATION OF THE BOILER ............................................................................................... - 1 - 1.3 BOILER STRUCTURE................................................................................................................................... - 2 -

2 BOILER PROPER.........................................................................................................................................- 4 -

2.1 DRUM ........................................................................................................................................................ - 4 - 2.1.1 SPECIFICATION OF DRUM......................................................................................................................... - 4 - 2.1.2 EQUIPMENT INSIDE THE DRUM ................................................................................................................ - 4 - 2.1.3 DRUM MAINTENANCE INSPECTION .......................................................................................................... - 4 - 2.2 LOWER DRUM............................................................................................................................................ - 9 - 2.2.1 LOWER DRUM TECHNICAL SPECIFICATION............................................................................................... - 9 - 2.2.2 MAINTENANCE OF LOWER DRUM ............................................................................................................ - 9 - 2.3 WATER WALL ........................................................................................................................................... - 11 - 2.3.1 TECHNICAL SPECIFICATION OF WATER WALL, STEAM-WATER CONNECTION PIPE, WATER WALL HEADER. - 11 - 2.3.2 MAINTENANCE OF WATER WALL AND HEADER....................................................................................... - 11 - 2.4 SUPERHEATER, REHEATER AND HEADER.................................................................................................. - 14 - 2.4.1 SPECIFICATION AND STRUCTURE OF SUPERHEATER AND REHEATER....................................................... - 14 - 2.4.2 MAINTENANCE OF CONVECTION SUPERHEATER .................................................................................... - 19 - 2.4.3 MAINTENANCE OF PLATEN SUPERHEATER ............................................................................................. - 23 - 2.4.4 MAINTENANCE OF FURNACE TOP AND ENCLOSURE SUPERHEATER......................................................... - 23 - 2.4.5 MAINTENANCE OF CONVECTION REHEATER .......................................................................................... - 23 - 2.4.6 MAINTENANCE OF RADIANT REHEATER................................................................................................. - 28 - 2.4.7 MAINTENANCE OF PLATEN REHEATER ................................................................................................... - 28 - 2.4.8 MAINTENANCE OF HEADER ................................................................................................................... - 28 - 2.5 ECONOMIZER ........................................................................................................................................... - 29 - 2.5.1 TECHNICAL SPECIFICATION OF ECONOMIZER TUBE, ECONOMIZER HEADER............................................ - 29 - 2.5.2 MAINTENANCE OF ECONOMIZER ........................................................................................................... - 29 - 2.6 BURNER ................................................................................................................................................... - 33 - 2.6.1 TECHNICAL SPECIFICATION OF BURNER................................................................................................. - 33 - 2.6.2 MAINTENANCE OF BURNER ................................................................................................................... - 33 - 2.7 ROTARY AIR PREHEATER.......................................................................................................................... - 34 - 2.7.1 TECHNICAL SPECIFICATION OF ROTARY AIR PREHEATER ........................................................................ - 34 - 2.7.2 MAINTENANCE OF ROTARY AIR PREHEATER .......................................................................................... - 35 - 2.8 DESUPERHEATER...................................................................................................................................... - 56 - 2.8.1 TECHNICAL SPECIFICATION OF DESUPERHEATER ................................................................................... - 56 - 2.8.2 MAINTENANCE OF DESUPERHEATER...................................................................................................... - 56 -

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2.9 BOILER WATER CIRCULATING PUMP ........................................................................................................ - 57 - 2.9.1 TECHNICAL SPECIFICATION OF BOILER WATER CIRCULATING PUMP ....................................................... - 57 - 2.9.2 STRUCTURE OF BOILER WATER CIRCULATING PUMP............................................................................... - 58 - 2.9.3 MAINTENANCE OF BOILER WATER CIRCULATING PUMP.......................................................................... - 58 - 2.10 HYDRAULIC PRESSURE TEST OF BOILER................................................................................................ - 62 - 2.10.1 CLASSIFICATION OF HYDRAULIC PRESSURE TESTS............................................................................... - 62 - 2.10.2 QUALIFIED CRITERIA OF HYDRAULIC PRESSURE TEST ......................................................................... - 62 - 2.10.3 CONDITIONS OF HYDRAULIC PRESSURE TEST ...................................................................................... - 62 - 2.10.4 HYDRAULIC PRESSURE TEST ............................................................................................................... - 63 - 2.11 MAINTENANCE OF BOILER STEEL FRAME, PLATFORM HANDRAIL AND MANHOLE................................. - 65 - 2.11.1 STRUCTURE OF BOILER STEEL FRAME.................................................................................................. - 65 - 2.11.2 MAINTENANCE OF BOILER STEEL FRAME, PLATFORM HANDRAIL AND MANHOLE.............................. - 65 - 2.12 SPECIAL TOOLS AND SPARE PARTS AND MATERIAL FOR MAINTENANCE OF BOILER PROPER ................. - 67 -

3 VALVE, WATER LEVEL GAUGE, PIPE AND ACCESSORIES ...........................................................- 68 -

3.1 MAINTENANCE OF SAFETY VALVE ........................................................................................................... - 68 - 3.1.1 STRUCTURE OF SAFETY VALVE ............................................................................................................. - 68 - 3.1.2 MAINTENANCE OF SAFETY VALVE ......................................................................................................... - 69 - 3.2 MAINTENANCE OF SOLENOID RELIEF VALVE ........................................................................................... - 80 - 3.2.1 MAINTENANCE OF SOLENOID RELIEF VALVE ........................................................................................ - 80 - 3.3 MAINTENANCE OF WATER LEVEL GAUGE.................................................................................................. - 85 - 3.4 MAINTENANCE OF DESUPERHEATING CONTROL VALVE ........................................................................... - 90 - 3.5 VALVES .................................................................................................................................................... - 92 - 3.5.1 MAINTENANCE OF HP GATE VALVE ...................................................................................................... - 92 - 3.5.2 MAINTENANCE OF HP STOP VALVE....................................................................................................... - 95 - 3.6 BLOWDOWN FLASH TANK........................................................................................................................ - 96 - 3.6.1 TECHNICAL SPECIFICATIONS OF BLOWDOWN FLASH TANK................................................................... - 96 - 3.6.2 MAINTENANCE OF BLOWDOWN FLASH TANK ....................................................................................... - 97 -

4 COAL PULVERIZING SYSTEM ............................................................................................................- 100 -

4.1 STEEL BALL COAL MILL ........................................................................................................................ - 100 - 4.1.1 STEEL BALL COAL MILL TECHNICAL SPECIFICATIONS ........................................................................ - 100 - 4.1.2 MAIN TECHNICAL PERFORMANCE....................................................................................................... - 101 - 4.1.3 STEEL BALL COAL MILL MAINTENANCE............................................................................................... - 104 - 4.2 COAL FEEDER ........................................................................................................................................ - 124 - 4.2.1 COAL FEEDER TECHNICAL SPECIFICATIONS ........................................................................................ - 124 - 4.2.2 COAL FEEDER MAINTENANCE ............................................................................................................ - 125 - 4.3 MAINTENANCE OF THE AUXILIARY EQUIPMENT OF THE COAL PULVERIZING SYSTEM ........................... - 128 - 4.3.1 MAINTENANCE OF THE RAW COAL BIN AND PULVERIZED COAL BUNKER .......................................... - 128 - 4.3.2 COARSE /FINE PULVERIZED-COAL SEPARATOR..................................................................................... - 132 - 4.3.3 MAINTENANCE OF WOODBLOCK SEPARATOR....................................................................................... - 135 - 4.3.4 MAINTENANCE OF WOOD SCRAPS SEPARATOR..................................................................................... - 136 - 4.3.5 AIR LOCKER MAINTENANCE ................................................................................................................ - 138 -

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4.3.6 COAL GATE MAINTENANCE ................................................................................................................. - 139 - 4.3.7 EXPLOSION DOOR MAINTENANCE ....................................................................................................... - 139 - 4.4 MAINTENANCE OF PULVERIZED FUEL FEEDER....................................................................................... - 140 - 4.4.1 TECHNICAL SPECIFICATIONS OF PULVERIZED FUEL FEEDER ................................................................. - 140 - 4.4.2 MAINTENANCE OF IMPELLER PULVERIZED FUEL FEEDER..................................................................... - 142 - 4.5 PULVERIZED COAL CONVEYER MAINTENANCE...................................................................................... - 148 - 4.5.1 PULVERIZED COAL CONVEYER TECHNICAL SPECIFICATIONS ................................................................ - 148 - 4.5.3 PULVERIZED COAL CONVEYER TROUBLE SHOOTING ............................................................................ - 154 - 4.5.4 OPERATION AND REPAIR ...................................................................................................................... - 156 - 4.6 JET LUBRICATION UNIT MAINTENANCE ................................................................................................. - 158 - 4.6.1 JET LUBRICATION UNIT TECHNICAL SPECIFICATIONS.......................................................................... - 158 - 4.6.2 JET LUBRICATION UNIT MAINTENANCE .............................................................................................. - 159 - 4.7 MAINTENANCE OF PRIMARY AIR PIPE ..................................................................................................... - 160 - 4.8 MAINTENANCE OF BAG-TYPE DUST COLLECTOR................................................................................... - 161 -

5 PRIMARY AIR FAN (MILL FAN), FORCE DRAFT FAN , INDUCED DRAFT FAN.......................- 162 -

5.1 PRIMARY AIR FAN (MILL FAN)................................................................................................................. - 162 - 5.1.1 TECHNICAL SPECIFICATIONS OF PRIMARY AIR FAN............................................................................... - 162 - 5.1.2 MAINTENANCE OF PRIMARY AIR FAN................................................................................................... - 163 - 5.2 FORCE DRAFT FAN.................................................................................................................................. - 170 - 5.2.1 TECHNICAL SPECIFICATIONS FORCE DRAFT FAN .................................................................................. - 170 - 5.2.2 TECHNICAL SPECIFICATIONS OF FORCE DRAFT FAN OIL STATION.......................................................... - 173 - 5.2.3 MAINTENANCE OF FORCE DRAFT FAN AND HYDRAULIC FLUID STATION............................................... - 173 - 5.3 INDUCED DRAFT FAN MAINTENANCE .................................................................................................... - 183 - 5.3.1 TECHNICAL SPECIFICATIONS OF INDUCED DRAFT FAN......................................................................... - 183 - 5.3.2 FUNCTION DESCRIPTION...................................................................................................................... - 187 - 5.3.3 PARTS DESCRIPTION ............................................................................................................................ - 190 - 5.3.4 INDUCED DRAFT FAN MAINTENANCE ................................................................................................. - 192 - 5.4 MAINTENANCE OF FUME DUCT AND AIR DUCT....................................................................................... - 199 - 5.5 AIR HEATERS AND PIPE MAINTENANCE ................................................................................................. - 202 -

6 ESP ..............................................................................................................................................................- 203 -

6.1 ESP TECHNICAL SPECIFICATIONS........................................................................................................... - 203 - 6.2 STRUCTURE OF ESP ............................................................................................................................... - 203 - 6.3 MAINTENANCE OF ESP .......................................................................................................................... - 203 - 6.3.1 MAINTENANCE OF CATHODE WIRE AND ANODE PLATE ...................................................................... - 205 - 6.3.2 CATHODE, ANODE RAPPING UNIT MAINTENANCE................................................................................. - 210 - 6.3.3 MAINTENANCE OF CATHODE SUSPENSION DEVICE AND LARGE/SMALL FRAME .................................... - 214 - 6.3.4 MAINTENANCE OF OTHER AUXILIARIES OF ESP .................................................................................. - 215 - 6.3.5 ESP ASH HOPPER AND SLIDE DAMPER.................................................................................................. - 218 - 6.4 TESTS AFTER ESP MAINTENANCE .......................................................................................................... - 219 - 6.4.1 PREREQUISITE FOR ACCEPTANCE TEST ................................................................................................ - 219 -

7. DOUBLE SCREW ROD AIR COMPRESSOR(ZRSERIES) ...............................................................- 221 -

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7. 1 DOUBLE SCREW ROD AIR COMPRESSOR TECHNICAL SPECIFICATIONS..................................................... - 221 - 7. 2 DOUBLE SCREW AIR COMPRESSOR STRUCTURE ..................................................................................... - 221 - 7. 3 MAINTENANCE LEVEL FOR DOUBLE SCREW AIR COMPRESSOR .............................................................. - 225 - 7.4.1 MAINTENANCE PREPARATION: ............................................................................................................. - 226 - 7.4. 2 DISMANTLING OF UNIT SYSTEM PARTS: .............................................................................................. - 226 - 7.4.3 DISMANTLING OF MINIMUM PRESSURE VALVE, OIL CUTOFF VALVE, AIR INLET VALVE AND OIL PRESSURE

REGULATOR ................................................................................................................................................. - 227 - 7.4.4 CHECK, VERIFY, REPAIR, REPLACE SYSTEM PARTS ............................................................................... - 227 - 7.4.5 WASHAFTERCOOLER:........................................................................................................................... - 228 - 7.4.6 CHECK SENSORS ................................................................................................................................. - 228 - 7.4.7 RECOVER ............................................................................................................................................ - 228 - 7.4.8 STARTUP COMMISSIONING:.................................................................................................................. - 228 -

8 OIL FREE SCREW AIR COMPRESSOR ..............................................................................................- 229 -

8.1 TECHNICAL SPECIFICATIONS .................................................................................................................. - 229 - 8.2 OIL FREE SCREW AIR COMPRESSOR CONFIGURATION............................................................................ - 229 - 8.3 MAINTENANCE AND SERVICE................................................................................................................. - 229 - 8.4 COMMISSIONING .................................................................................................................................... - 230 -

9 REFRIGERATED AIR DRYER...............................................................................................................- 231 -

9.1 RSL TYPE REFRIGERATED AIR DRYER TECHNICAL SPECIFICATIONS...................................................... - 231 - 9.1.1 WORKING PRINCIPLE DESCRIPTION .................................................................................................... - 231 - 9.1.2 REFER TO FIGURE 1 FOR THE WORK PROCEDURE OF THE REFRIGERATED AIR DRYER. .......................... - 231 - 9.1.3 PROCESS DESCRIPTION ....................................................................................................................... - 232 - 9.2 MAINTENANCE AND SERVICE................................................................................................................. - 233 - 9.2.1 PRINCIPLES ......................................................................................................................................... - 233 - 9.2.2 CONTENT ............................................................................................................................................ - 233 - 9.2.3 RSL AIR DRYER TROUBLESHOOTING............................................................................................... - 234 -

10 GASIFICATION BLOWER ...................................................................................................................- 238 -

10.1 TECHNICAL SPECIFICATIONS ................................................................................................................ - 238 - 10.1.1 WORKING PRINCIPLE ........................................................................................................................ - 238 - 10.2 MAINTENANCE AND SERVICE OF THE BLOWER CAN BE AS PER THE TABLE BELOW. ............................... - 241 - 10.2.2 ASSEMBLING..................................................................................................................................... - 243 - 10.3 MAIN PARTS AND CONSUMABLES ........................................................................................................ - 248 - 10.3.1 LIST OF MAIN PARTS ......................................................................................................................... - 248 - 10.3.2 CONSUMABLES ................................................................................................................................. - 249 -

11 SLAG REMOVAL SYSTEM...................................................................................................................- 250 -

11.1 SLAG HOPPER MAINTENANCE AND SERVICE........................................................................................ - 250 - 11.1.1 SLAG HOPPER AND SLAG GATE STRUCTURE .................................................................................... - 250 - 11.1.2 SLAG HOPPER AND MAINTENANCE AND SERVICE ............................................................................. - 250 - 11.2 SLAG CRUSHER MAINTENANCE AND SERVICE ..................................................................................... - 254 -

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11.3 SLURRY PUMP MAINTENANCE AND SERVICE........................................................................................ - 258 - 11.3.1 TECHNICAL SPECIFICATIONS............................................................................................................. - 258 - 11.3.2 SLURRY PUMP MAINTENANCE.......................................................................................................... - 259 - 11.4 DEHYDRATION GRANARY MAINTENANCE AND SERVICE ...................................................................... - 263 - 11.4.1 BRIEF INTRODUCTION ....................................................................................................................... - 263 - 11.4.2 PROCEDURE AND QUALITY STANDARDS ........................................................................................... - 263 - 11.5 MAINTENANCE OF CONCENTRATION TANK AND BUFFER TANK............................................................ - 265 - 11.5.1 MAINTENANCE PERIOD: AS PER THE SYSTEM OVERHAUL.................................................................. - 265 - 11.5.2 MAINTENANCE ITEMS ....................................................................................................................... - 265 - 11.5.3 MAINTENANCE PROCEDURE AND QUALITY STANDARDS. ................................................................... - 265 - 11.6 MAINTENANCE OF PUMPS IN THE SLURRY SYSTEM.............................................................................. - 266 - 11.6.1 HIGH, MEDIUM, AND LOW PRESSURE PUMPS..................................................................................... - 266 - 11.6.2 BACKWASHING PUMP........................................................................................................................ 343H- 270 - 169H11.6.3 DREDGE PUMP .................................................................................................................................. 344H- 270 - 170H11.6.4 LIFT PUMP......................................................................................................................................... 345H- 270 -

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1 Main Technical Specifications and Structure of Boiler ( Taking SG-995/17.3-MMX Boiler as Example)

1.1 General

W-flame boiler has a different structure from regular coal-fired boiler. It’s combustion chamber consists of lower combustion chamber and upper burn-out chamber. The depth of combustion chamber is 80%-120% greater than that of burn-out chamber. The top of the front project part form the arch, on which the pulverized coal flow and secondary air nozzles are placed (Some W-flame boiler arches are only equipped with pulverized coal flow and steam exhaust nozzles). The jeting down pulverized coal extends downward after being fired. In the lower part of combustion chamber, it meets tertiary air, then turns upward, rising along the axis of furnace chamber, thus forming the W-shape flame. The burned product rises to the burn-out chamber.

Generally, the W-flame boiler is divided into wet bottom boiler and dry bottom boiler. The aboard practice indicates the biggest problem from W-flame wet bottom boiler is the large amount of NOx emission, further, there are also problems such as high temperature erosion of water wall tube, long time of maintenance, weak capability of peak load regualtion. So in general, the wet bottom boiler is not adopted; W-flame dry bottom boiler can steadily burn anthracite and meager coal, Vdaf=6%~20%, and even the anthracite, Vdaf=4% can also be burned. So, this kind of boiler is recommended by general aboard companies. The boilers having been put into services are also such kind of boilers.

To ensure the burning of anthracite or meager coal, the primary air rate of W-flame boiler is lower, which is 15% to 20%. For the penetrating depth is insufficient due to the own air amount and flow rate of primary air,large amount secondary air must be send from the arch. The lead jet of secondary air from the arch is utilized to ensure the better penetration depth of the primary air.

1.2 Technical Specification of the Boiler

Supplier: Shanghai Electric Group

Type: SG-995/17.3-MXX

Style: Subcritical controlled circular drum furnace, double arch W-flame single furnace, axial burning, primary middle reheated, two-stage attemperating, balancing ventilating, openair disposed, dry ash handling, all-steel structural, all suspended structural II-model boiler

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Boiler Type SG-995/17.3-MXX

Main parameters of boiler

B-MCR t/h 995

Rated evaporation(RO) t/h 889.1

Steam Pressure (B-MCR/RO) MPa·g 17.29/17.13

superheated steam Steam Temperature(B-MCR/RO) 541/541

Steam flow(B-MCR/RO) t/h 882.498/736.407

Inlet,outlet steam pressure(B-MCR) MPa·g 3.53/3.34

Inlet,outlet steam pressure(RO) MPa·g 3.14/2.98

Inlet,outlet steam temperature(B-MCR) 320/540

Reheated Steam

re

Inlet,outlet steam temperature(RO) 309/540

Feedwater temperature(B-MCR/RO) 281/273

1.3 Boiler Structure

The boiler proper is designed by Alstom, and its technical support of commisioning and performance test is also supplied by Alstom, it is made by Shanghai Boiler Works, Ltd. The style of boiler is double-arch W-flame single-furnace, primary middle reheated, forced water circular, subcritical drum boiler. Two units are equipped with one startup boiler, which acts as the startup steam source during the unit startup;

The coal type of the boiler is anthracite, which is from CAM PHA mineral area and HON GAI mineral area in Vietnam.

Combustion system: it adopting hot air for pulverized coal feeding, each boiler equipped with 16 dual-split double direction pulverized coal feeders and 32 burners. The capacity of pulverized coal burner is 100% BMCR of designed coal type. The startup and flame stablizing of boiler uses heavy oil, according to standard of TCVN 6239-2002. The boiler employs two-stage ignition, i.e., the heavy oil gun is fired by the electric spark of high-energy ignitor, then the heavy oil gun ignite the pulverized coal. Oil gun adopts steam atomization. For the project, 2×5000 ton oil tanks, 2 oil drain pump, 2 × 100% capacity AC/DC oil feeding pump, 1 dirty oil pump and 1 sewage pump are disposed.The fuel system is disposed the oil feed pipe/oil return pipe to burner of boiler according to the principle of single oil feed/return main pipe.

Oil burner: there are 8 heavy fuel oil HFO) burner at each folded flame corner, i.e., each boiler equipped with 16 burners. Auxiliary steam with pressure stablized at 5.25 bar(g) allow HFO attain at atomization state, the auxiliar steam is also used for burner clean. The heavy oil is ignited via the high energy ignitor, each HFO burner is equipped with special flame inspector.

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Cooling wind is provided to burner and flame inspector via two independent special loops. During stop, fuel burner retreated from burner nozzle about 330 mm, to prevent the affection of boiler radiation( avoiding the burnout of oil burner). All burning capacity (LHV base value) 30% BMCR fuel heat input value, only adopting 12 burners can attain 30% BMCR burning capacity (two burners per folded flame corner stop operation). The regulation ration of burner is 1:5. J11 oil burner is employed.

Smoke exhaust and ash system of boiler: the smoke exhaust system adopts negative balancing ventilation style, smoke and gas come from ESP to FGD, then exhausted to atmosphere, or directly vented to atmosphere via FGD bypass. Induced/forced draft fan is axial type, forced draft fan is adjustable moving-blade one, and induced fan is adjustable static-blade one. The pulverizing system is warehouse type, smoke drying pulverizing system, adopting negative pressure ventilation. Each boiler is equipped with two single-in-single-out BBI ball miller. The primary fan (pulverized coal exhauster) use centrifugal fan. The smoke exhaust goes through the fabric filter undergoing the pulverized coal filtering, and then to the smoke exhauster, being vented to the atmosphere.

Ash handling and ash yard: dry bottom handling style is adopted. The bottom ash is discharged to ash sump via the slag crusher, hydraulic ejector. The ash collected from air preheater, ECO and electric precipitator is sent to large scale ash silo (each of the two silos has capacity of 2500 m3). Dry ash is further sent to ash slurry pond through blending of ash and water, and then conveyed to ash yard by ash slurry pump (Composite utilization of dry ash is kept at the same time).

Dust collection and desulphurization system: four-electric field electrostatic precipitator is chosen. For this phase, a 200m-height dual steel flue stack will be built. Synchronously, 100% capacity FGD is to be built, adopting wet desulphurization process, limestone-plaster forced oxidation, using gas - gas heat exchanger (GGH);

Compressed air system: this system is considered according to less lubricant, three 50% capacity compressors are equipped.

Safety valve: Spring loaded safety valves from Crosby Company of U.S.A. are used for the boiler. Detailed position: 3 pieces for boiler furnace， 1 piece disposed at outlet pipe of superheater, 2 pieces for inlet pipe of reheater, 2 pieces for outlet pipe of reheater, also a electromagnetic relief valve(ERV) is placed at outlet pipe of superheater, with brand of VTI, USA, supplied in whole unit by Crosby Company. The maximum evaporation is 995t/h, total discharge amount of safety valve of boiler drum is 881.796t/h, accounting for 88.62% of maximum evaporation, the discharge amount of superheater safety valve is 153.86t/h, account for 15.46% of maximum evaporation, the sum of total discharge amount of boiler drum and superheater is 1035.656t/h, being 104.09% of maximum evaporation. The maximum flow rate of reheated steam is 848.6t/h, the sum of total discharge of reheater inlet safety valve is 512.94t/h, accounting for 60.45% of maximum flow rate of reheated steam, the sum of total discharge of reheater outlet safety valve is 379.157t/h, accounting for 44.68% of maximum flow rate of reheated steam，the sum of total discharge of reheater inlet/outlet safety valve is 892.097t/h, account for 105.13% of maximum flow rate of reheated steam. The discharge rate

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of dynamic discharge valve is 166t/h, occupying 16.68% of total evaporation of boiler, its discharge will not be included in discharge rate of safety valve.

2 Boiler Proper

2.1 Drum

2.1.1 Specification of drum

In the drum, along the direction of length, arranged circular interlayer, eddy-current separator, corrugated plate separator, louver moisture separator, water feeding distribution header, continuous blowdown pipe and inlet flow equalizing plate, cross plate of downcomer.

2.1.2 Equipment inside the drum

Designation Quantity

Material Designation Quantity

Material

Arc diaphragm 14 pcs AY3F Inlet equalizing pipe of downcomer

4

Seat plate of separator 14 pcs AY3F Cross plate of downcomer

4

Lower support of separator

56 pcs EG25 Pipe φ48×5, L＝406 4 20 steel

Eddy-current separator 56 pcs Sampler inside the drum 1

Corrugated plate dry box

72 Pipe φ51×4, L＝566 36 20 steel

Sluice tube plate 18 Pipe φ51×4, L＝ 18 20 steel

Water feeding distribution header

1 Pipe φ51×4, L＝ 18 20 steel

Blowdown piping 1 Stud connection 12

Sluice pipe 18

2.1.3 Drum maintenance inspection

Maintenance item

Workmanship and precautions Quality standard

I Maintenance preparation

1. Remove insulation cover of manhole at both sides, remove the manhole door screws with drum manhole special gate spanner. After remove, the manhole screws and nuts should be placed in special oil tank or oil disc to

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avoid loss and rust.

2.Open manhole door, mount draft fan to cool down the inside of drum. Maintenance person can only enter the drum after the temperature of drum decrease below 40℃.

3. To prevent the tools and parts fall into the downcomer, after take down the filter screen of downcomer, rubber should be laid on the bottom of drum. When carry out job inside the drum, the maintenance person must strictly comply with the requirement of Clause 270 of “Safe Operation Regulation of Electric Industry”(Thermal Machinery Section)”.

4.electric tools and lighting used in drum must meet the requirements of Clause 272, 273 and 274 of “Safe Operation Regulation of Electric Industry”(Thermal Machinery Section)” issued by certain Ministry.

5. After the open of manhole door, temporary manhole gate must be mounted. During the maintenance, the maintenance person should close the temporary manhole door when he/she leave the drum.

II Inspection of facilities & accessories inside the drum and dirty clean

1. Firstly, the chemical supervision personnel inspects the fouling and rust inside drum and the surfaces of inner facilities.

2. Check and record the completeness, leakproofness and security.

3. Check the connection screw and fastening screw of moisture separator.

4. Clean the surface fouling of drum and moisture separator.

Caution: Do not damage the glossy anticorrosion film on the metal or its surface.

5. Clear and dredge the blowdown pipe, sample pipe, chemical feed pipe, connection pipe of water gauge and pressure meter.

1. The completeness of the moisture separator, without loose, tilting and corrosion; the louver has no damage and deformation .

2. No fall-out, loosing to the connection screw and fastening screw of moisture separator.

3. Cleanness of the inner surface of drum and surfaces of moisture separator and accessories.

4. Free-flowing in the

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blowdown pipe, sample pipe, chemical feed pipe and connection pipe of water gauge and pressure meter.

III remove & assembly of facilities in drum

1. Before disassembly, number the moisture separator according to sequence of left-right-front-back.

2. When dismantling, first remove the draining pipe and the cyclone separator barrel and connection screw and fasten screw of top hat, then take down the separator and top hat.

3. Remove the connection screw of support plate of dry box; draw out the dry box along the support plate.

4. After remove the connection screws and fixed screws, count out them, and not to leave them in the drum.

1. Moisture separator and cleaning hole mounted correctly.

2. Cyclone separator cartridge and top hat may be kept vertical and smooth.

3. No loosing of the connection screw and fixing screw.

IV Inspection of welding joint inside/outside the drum, inner wall corrosion and crack

1. Polish the surface of longitude joint and circular joint of inside/outside the drum and 100-150mm area along weld with polisher. Detailed section and length should be stated by the metal supervision personnel.

2. After clean of drum inner wall, check erosive point and crack on the surface of inner wall. If common erosive points and cracks are found, polish them with polisher. For serious erosive points and cracks, report to higher technical department for making special technology measures.

1. Polish the weld and surfaces along the weld, removing the fouling and rust, showing the original metal color.

2. After erosive point and crack polishing, such polished section should be flat and smooth, having no edges and corners.

V downcomer pipe and other visible pipe seat weld inspection

1. According to requirements of metal supervision, polish the edges of drum downcomer seat weld. After that, the metal supervision personnel carry out flaw detection on polished surfaces.

2. Clear the fillet weld of cross plate of

1. Edges of downcomer seat inside the drum have no crack.

2. the fillet welds of cross plate of downcomer have no

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downcomer, and inspect the fillet welds. If cracks exist, polish them until removal.

3. Inspection of fillet welds of connection pipe seats of blowdown, chemical feed, water gauge and pressure meter. If cracks exist, deal with them.

4.Grind the edges of pipe seat corners of safety valve with polisher, and give flaw inspection to fillet welds by the metal supervision personnel.

crack and erosion.

3. The fillet welds of connection pipe of blowdown, chemical feed, water gauge and pressure meter have no cracks.

4. The fillet welds of safety valve pipe seat have no crack.

VI Weld inspection of inner parts of drum

1. Check the circular isolating plate and upper side plate welds with light transmission method, if any, repair weld.

2. Check the tee pipe of water distribution pipe and side heads with light transmission method. If any cracks, repair weld.

3.Clear embedded parts’ welds of manhole hinges. If any cracks, grind and repair weld them.

Note: Do not generate arc from drum.

1. The welds of circular isolating plate and side plates have no cracks.

2. Welds of Tee of water distribution pipe and side heads have no cracks.

3. The fillet welds of manhole hinges have no cracks.

VII Drum levelness measurement

1. The drum levelness measurement shall base on the horizontal central lines of side circumference.

2. Use a rubber pipe with glass pipe plugged in both ends, full water in the rubber pipe, and put the two end glass pipe on the side circumferential horizontal lines.

3. Measure and record the distance from drum central line to glass pipe water level, compare the distances of two sides. The difference is deviation of drum levelness.

VIII Maintenance of manhole door

1. Clear the junction surface of doorframe and doorplate of the manhole door with

1 The junction surface of frame and plate should be smooth.

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butt chisel and sand paper.

2. Check the junction surface of doorframe and doorplate. If cracks or flaw points exist, grind them. For trace of blowing damage, carry out bead welding after grind, and then grind it again.

3. Kerosene should be used for clean of the screws and nuts of the manhole door; and then check the threads of such screws and nuts. The thread burr should be repaired with file or on the machine tool; for those have serious fault, change them.

4.The hardness of screw should be checked for each over haul.

Use special flat ruler and filler gauge to check 12-1 points along circumference of the grinded surface, the error should be less than 0.1-0.2mm.

2. The screws and nuts of manhole door have no burrs and breaks.

3. Screw hardness HB＝197.

IX support/suspension frame check

1. Check the contact of derrick and drum.

2. Check the appearance of suspension nut of derrick.

3. Check the appearance of derrick.

1. Derrick and drum well contacted, having large contact area.

2. The suspension nuts of derrick are even loaded, and have no erosion on surface.

3. The derrick surface has no erosion.

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X close of manhole

1. After the maintenance inside drum, the maintenance tools should be taken out, and count, reviews them.

2. Last inspection should be given to drum before close manhole.

3. Before close manhole, the high pressure seal gasket, and coat the door frame, door plate, screws and nuts with molybdenum disulfide.

4. After close the manhole, check the contact circumstance of junction surface with filler gauge.

5. After cold state fasten of the manhole door, hot fasten the door again when the pressure increase to 0.3—O.5MPa.

1. No foreign matter in the drum.

2. The junction surface is well contacted after manhole closed.

3. The fixing screws are even loaded after manhole closed.

2.2 Lower Drum

2.2.1 Lower drum technical specification

The circular structured lower drum, Φ914mm, will replace lower header of all evaporation heating absorption area. It has the same function with normal low header of boiler water wall. The lower drum is equipped with multi-hole strainer cover and orifice plate, the diameter of strainer is 0.6mm with opening area ratio of 52%. The function of the strainer is to prevent the foreign matter entering the water wall tube. The orifice plate is mounted in the inlet end of the water wall tube. Each tube is equipped with orifice plate. The function of the orifice plate is to normally distribute the feed water, ensuring the safe operation of water wall. The diameter of orifice plate is calculated for each loop and each water wall tube according to heat load distribution curve along the direction of furnace height and the different flow resistance under different working condition.

2.2.2 Maintenance of lower drum

Maintenance item Workmanship and precautions Quality Standard

I Preparation before maintenance

1. After the open of manhole, the chemical supervision personnel enter the drum to check the erosive points and sample the scale.

2. Pave rubber on the nozzle of front and rear drain pipe to prevent the falling in

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of tools.

II Disassembly of orifice plate

1. Number the cover of multi-hole strainer, remove the fixed screw of the cover, and take down it.

Note: After remove the screws of cover, take them out of the drum, and count them.

2. Group and number the orifice plate.

3. Remove the retainer enclosed the orifice plate, take down the orifice plate.

Note: After remove the screws of cover, take them out of the drum, and count them to store collectively.

4. After removal, the orifice plate must be put into oil disc or other container to wash. If meet with acid cleaning, the orifice plates and multi-hole strainer cover may not be removed, cleaning with the system. But, after that, spot check a group of orifice plate to find the result of acid cleaning.

5. After plate clean, spot check orifice plate to measure the diameter of hole. If the diameter exceeds the standard, change the plate.

6. Assemble the orifice plate according to the number. Do the same with strainer cover.

7. After reassembly of orifice plate retainer, check the looseness.

1. The orifice plate is smooth, with correct mounting position.

2. After assembly, the orifice plate should be secure without loose.

3. The surface of strainer cover should be smooth and clean.

4. The mounting position of multi-hole strainer cover is correct. And the cover has no loose after installation. 5. The change rate of hole diameter of orifice plate should be less than 5%.

III Inside clean of lower drum

1.Clear the fouling in the inner wall of lower drum, pipe seat of water wall and of downcomer with wire brush and compressed air.

2. Clear the fouling on the surface of

1.The inner wall of lower drum is smooth, free of fouling.

2.There is no fouling on

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mulit-hole strainer cover with wire brush and compressed air.

the pipe seat of water wall and downcomer.

3.The orifice plate is flat and smooth.

4.The surface of strainer cover is smooth, free of fouling.

2.3 Water Wall

2.3.1 Technical specification of water wall, steam-water connection pipe, water wall header.

The water wall, adopting all welding type membrane water wall, together with drum, furnace water circling pump and lower drum etc., form several force-flow independent loop. The water wall has two types, i.e., smooth pipe and inner thread pipe.

2.3.2 Maintenance of water wall and header

Maintenance item

Workmanship and precautions Quality Standard

I Preparation of water wall maintenance

1.Erect firm and stable scaldfold from bottom ash hopper to inlet elbow of wall reheater around ther furnace.

2.When use elevating platform in furnace, make sure to operate according to sepecification.

Note: Do not exceed the limited weight or serve as lifting tool when use elevating platform.

3.Certain number of lights should be put in the furnace to ensure sufficient lighting of the furnace. The power line to the furnace should be overheaded.

II Coke and ash cleaning of water wall

1.Before coke cleaning of water wall, a wood board should be paved on the slope of bottom ash hopper to separate the furnace and the hopper, in order to prevent strike of coke on the slope water wall tube.

2.Strike the coke suspending on the water wall upside down with hammer, let it break away from the water wall.

1.There is no coking or ash deposit on the surface of water wall.

2. No damage to the water wall surface.

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Note: Do not damage the water wall when stike and remove the coke.

3. Remove the thin coke and ash deposit attached to the water wall with round spade along the surface of water wall.

III Visual inspection of water wall

1.Use thickness tester to measure the water wall thickness besides the burner and around the blow hole of soot blower and the thickness of suspending pipe.

2. Use a slide caliper or caliper gauge to measure the expanded value of pipes along the both sides of burner and suspended pipe at furnace outlet.

Note: Remove the ash deposit on the surface of pipe with brush before measurement.

3. Check the deformation, pits of water wall tube of bottom ash hopper slope and erosion points near the water seal trough.

4. Check the crack of fin of water wall, if any, repair weld with electric welding.

5.With respect to water wall tube at high heat loaded area, also performance the high temperature erosive inspection.

1. The reduced value of thickness of worn pipe should be less than 30% of tube thickness.

2. The expanded value of pipe should be less than 3.5% of tube diameter.

3. The slope water wall of bottom ash hopper has no deformation and pits, the depth of erosive points of tube should be less than 30% of tube thickness.

4. The fins of water wall have no crack.

IV Sampling of supervision tube

1.The location of supervision tube of water wall may be determined by the metal supervision personnel.

2. For the cut of supervision tube, the cutting point should avoid the rigid beam of water wall, and also stagger with the weld of adjacent tube, the distance staggerred may be more than 50 mm. Further, after cut, the fin of water wall should be cut more than 25mm along the wall to ensure the welding quality.

3. The length of supervision tube usually is not less

1. The cut position of tube is correct. The distance that cut point away from the rigid beam and bend start point of elbow should be more than 150 mm. The cut point shoud be more than 150 mm away from the

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than 250 mm, the sampling tube should include the new and old section.

4.During the cutting, do not damage the tube proper and adjacent tube. Try to use machine to perform the cut and avoid the falling of weld slag into the tuge when using flame cutting. Following completion, seal the tube open to the top.

5. After remove the supervision tube, show the location of supervision tube, the side facing flame and flow direction of fluid in the tube.

adjacent weld seam at same tube.

2.The sample tube and adjacent tube have no damage.

V Replacement of tube

1.Following the tube cut, use facing machine to make the divided edge of cross section. Before butt welding, the pipe inner/outer wall should be ground until showing proper metal color. The length to be ground is 10-15mm in general.

2.Before the cut of new tube, visual inspection and pipe thickness measurement should be given to tube. For curved tube, the ellipticity of bending section should be carry out and given ball passing test. Additionally, aid cleaning may be implemented before use, and purge the tube by the aid of compressed air before butt welding.

3.Argon arc weld may be used for pipe, or with the argon arc weld as the backing, electric weld as the covering technology. There will leave 3 mm gap between pipes.

Note: Do not butt weld forcely. After the tack weld, not to strike with hammer.

4. Following the of weld, carry out flaw detection to the tube. The fins can be restored after confirm the qualification of weld seam. The expansion efficient of fins should be in line with that of fin tube. Seal welding will be adopted.

5.When replacing suspended tube, the cold-drawn dimension of tube should be measured and recorded after the cutting of tube to ensure the cold-drawn value during the restore of tube. When replacing several suspended tubes, it

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should be done one by one. Do not cut two or more tubes at the same time.

2.4 Superheater, Reheater and Header

2.4.1 Specification and structure of superheater and reheater

2.4.1.1 Structure of superheater and reheater

According to gas flow process, the superheater system is divided into five stages, i.e.,separation platen, rear platen, last stage, enclosure and low temperature superheater; according to steam flow process, such system is divided into such five stages as top furnace, low temperature superheater, separation platen, rear platen and last stage convection superheater:

Reheaters are well distributed at high temperature gas area, they are classified into three stages: wall reheater, platen reheater and last stage reheater. The wall reheater is low temperature reheater, disposed at front wall on top of furnace and front side of two-side walls, close to the water wall and cover the water wall.

2.4.1.2 Technical specification of superheater and reheater

The wall thickness of superheater tube is determined by strength, of which the material is depended on work temperature of superheater and relied on the principle of safety and economic.

No. Item Unit

1. Saturated steam tube

Nominal outer diameter mm 57/44.5

Longitudinal distance mm 127.5/153

Material

Quantity 136

Outlet steam temperature ℃ 362

Pressure drop from lower drum to superheater outlet under condition of BMCR

kg/cm2 14.1

2. Saturated steam header

Quantity 1

Nominal outer diameter mm 244.5

Nominal bore diameter mm

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Length m About 15.8

Material SA106 C

3. 1st stage superheater

Quantity 1

Gap of tranverse gas flow mm 102

Gap of gas flow direction mm 89

Nominal outer diameter of tube mm 44.5

Heat absortion area(effective) m2 about 8150

Total circumferential heat area m2 Should be announced

Gas duct area m2 Should be announced

Material SA210C

SA209T1

Platen quantity 149

Steam flow tube number 447


Total effective heat absorption area of superheater(net weight)

m2 About 8150


kg/ cm2 2.1

Steam flow rate in the desuperheater m/s 6.7

Maximum gas flow rate under condition of BMCR m/s 10.5

4. Inlet header of 2nd superheater(platen type)

Quantity 1


Length m About 16.3

Material SA106C

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5. 2nd superheater(platen type)

Quantity 1

Transversal gas flow mm 765

Along flow direction mm 58.3


Effective heat absorption area m2 1610

Material SA213T22

SA213T2

SA213T11

SA213TP347H

Platen quantity 19

Gas flow tube number 266



m2 1610


kg/ m2 3.8



6. 二 Inlet header of 2nd superheater(platen type)

Quantity 1

Nominal outer diameter mm

Nominal inner diameter mm 260

Length m About 15.6

Material SA335P22

7. Platen superheater N/A

8. Inlet header of superheater

Quantity 1

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Nominal bore diameter mm Should be announced

Length m About 15.8

Material SA335

P12

9. Last stage superheater

Quantity

Tube gap

Gap of transversal gas flow mm 127.5

Gap of gas flow direction mm 76

Nominal outer diameter of tube mm 38

Effective heat absorption area m2 About 4070.

Material SA213T22

SA213T9.1



m2 About 4070.


kg/cm2 2.1



10. Outlet header of last stage superheater

Quantity 1

Nominal outer diameter mm

Nominal bore diameter mm 280

Length m About 16.4

Material SA335

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P91

11. Desuperheater

Method Water spraying

Control range of superheater 60%~100%

Control range of reheater 60%~100%

Maximum water spraying amount(superheater/ reheater)

kg/h 20000/25000

12. Inlet heater of low temperature reheater

Quantity 1+2


Nominal bore diameter mm

Material SA106C

13. Low temperature reheater

Quantity 1

Gap of transversal gas flow mm 51

Gap of gas flow direction mm N/A


Heat absorption area(effective) m2 500

Material

Platen quantity 602

Steam flow tube number 602

Departure temperature ℃ 389


m2 500


kg/m2 0.7

Control equipment of steam temperature m/s 27.0

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Maximum gas flow rate under condition of BMCR m/s N/A

14. Outlet header of low temperature reheater Should be announced

Quantity 1+2


Material SA335P12

2.4.2 Maintenance of convection superheater

Maintenance item Workmanship and precautions Quality standard

I Ash cleaning of heat absorption surfaces

1.With compressed air, clean upside down the ash deposits on the low temperature superheater, tube surfaces of enclosure superheater and horizontal gas duct.

2. Rinse the ash deposits on the surfaces of tubes of separation platen superheater, rear platem superheater and last stage superheater.

3.When flush with water, protective work for back stack well should be done to prevent water entering the back stack well.

4. When blow coke around the enclosure superheater, coke blocks should be broken with hammer for further cleaning.

Note: Do not damage the tube.

1.No ash deposit and coking on heating surfaces of tube.

2.There is no coking and other foreign matter between tube rows.

II Anti-wear inspection of tube for heat absortpion

1.Pay more attention to inspect the straight tube section of low temperature superheater tube row on both sides of suspended tube, 90°elbow of upper/lower connection tube, elbow of upper/lower tube rows close to the back enclosure, and tubes with the blow range of blower. If worn tube is found, then measure the thickness of tube with thickness tester. And separately spot check two tubes to measure and record tube thickness.

2.Emphasisly check the contact section of

The reduced thickness of tube should be less than 30% of tube thickness.

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platen superheater and horizontal position tube, tube of last stage superheater deformed tube row, tubes within the range of blow of blower. If worn tube is found, then measure the thickness of tube with thickness tester. Also spot check and record tube thickness.

3.Check the rear enclosure tube at gas inlet section of low temperature superheater and economizer, and enclosure tube around the blow hole of blower.

III Creep expansion inspection of tube at tube heat absorption area

1.With slide caliper or pipe caliper, measure the tube diameter of lead tube of low temperature superheater, outer tubes of separation platen superheater, outer tubes of rear platen and the first tube at flame-facing side of last stage superheater.

Note that before measurement, clean the ash deposits on the surface of tube and coke attaching to the surface of tube. During measuring, the slide caliper should be perpendicular to tube.

2.Macroscopic inspection of the appearance of tube.

1.The expansion value of carbon steel tube of superheater is less than 3.5% of tube diameter.

2. The expansion value of alloy steel tube of superheater is less than 2.5% of tube diameter.

3.The appearance of tube has no obvious color variation.

4.There is no crack on the surface of tube, and the thickness of oxide skin should be less than 0.6 mm.

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IV Inspection and reshaping of tube row

1.Check the flatness and transversal pitch of tube row. If deflection or curving exist to tube row, find the reason of distortion or the deformation points. According to the reason, change the tube clip, restore the flatness of tube row. For serious deformed tube rows or single deformed tube deviate from tube row, the deformed section should be cut away to restore the origin pitch and flatness, and then recover by the aid of new tube. Change the transversal live connection board of deformed tube row, retighten the connection of platen superheater and horizontal location arm to restore the transversal pitch of tube row.

2. When replacing the tube clip or strap, electric weld or grinder may be used to cut the original parts. Note, do not damage the tube when carry out cutting. Before welding of fixing block of tube clip and strap, grind the crator left on the tube.

3.When replacing the tube clip, be sure not to weld the clip and tube together, similarly, the tube straps can not be weld each other when to be replaced.

4.The material of fixing parts should be the same to that of original parts.

1.The tube rows are flat, and transversal pitches are even.

2.The tube clip, tube strap and transversal live connection board of tube row are sound, without shedding, burning out, deformation, they are well fixed to tube row and can freely expand with tube.

3.Horizontal locating tube and platen superheater are well tightened, tube straps without droping off.

4.The material used for fixing part of tube clip is correct.

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V Inspection of supervision sampling tube

1.The cutting position of supervision tube is to be determined and recorded by the chemical supervision personnel.

2.Cut the supervision tube with special mechanical machine. The cutting point should be deviated from tube clip and the flex point of elbow for 150 mm. If such position is last sample one, then the replaced tube should also be removed. The length of supervision arm should be more than 250 mm.

3.After the removal of supervision tube, the opening to the top should be plugged immediately. Position, direction of fluid and direction of gas side may be marked on the supervision tube.

4.Measure the thickness of sampling tube with thickness tester.

The cutting position of supervision tube is correct.

There is no damage to the inner/outer wall of supervision tube.

VI Tube replacement

1. Following the cut of tube, use facing machine to make the divided edge of cross section.

2. Before butt welding, the pipe inner/outer wall should be ground until showing proper metal color. The length to be ground is 10-15mm in general.

3. Before the cut of new tube, visual inspection and pipe thickness measurement should be given to tube. For curved tube, the ellipticity of bending section should be carry out and given ball passing test, if neccessary. Purge the tube by the aid of compressed air before butt welding. For alloy steel tube, spectrum inspection should be performed before butt welding.

4.The welding technology of tube should meet the requirement of “Technical Specification of Electric Building

1.The divided edges of tube are smooth and flat. The angle machining of edges is the same with water wall.

2.New tubes have no traces of cracks, erosion, mechanical damages, the nagative tolerance of tube thickness should be less than 1% of tube thickness. The reduced amount of thickness of

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Construction and Acceptance”weld section of thermal power plant”(DLS007-92).

5.If number of replaced tubes exdeeds 50% of total, hydraulic pressure test should be carried out.

curved tube should be less than 10% of tube thickness. The ellipticity should be less than 6%. The ball passing test is qualified.

3.There is no dirt, foreign matter in the new tubes.

4.The flaw detection to weld seam following the weld is qualified.

2.4.3 Maintenance of platen superheater

Maintenance content: being same as above 2.4.2 maintenance of convection superheater

2.4.4 Maintenance of furnace top and enclosure superheater

The maintenance is the same as above 2.4.2 maintenance of convection superheater

2.4.5 Maintenance of convection reheater


I Ash cleaning of heating surface

1. With compressed air, clean upside down the ash deposits on the low temperature superheater, tube surfaces of enclosure superheater and horizontal gas duct.

2. Rinse the ash deposits on the surfaces of tubes of separation platen superheater, rear platem superheater and last stage superheater.

3. When flush with water, protective work for back stack well should be done to prevent water entering the back stack well.

4. When blow coke around the enclosure superheater, coke blocks should be

1. No ash deposit and coking on heating surfaces of tube.

2. There is no coking and other foreign matter between tube rows.

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broken with hammer for further cleaning.

Note: Do not damage the tube.

II Anti-wear inspection of tube for heat absortpion

1. Pay more attention to inspect the straight tube section of low temperature superheater tube row on both sides of suspended tube, 90°elbow of upper/lower connection tube, elbow of upper/lower tube rows close to the back enclosure, and tubes with the blow range of blower. If worn tube is found, then measure the thickness of tube with thickness tester. And separately spot check two tubes to measure and record tube thickness.

2. Emphasisly check the contact section of platen superheater and horizontal position tube, tube of last stage superheater deformed tube row, tubes within the range of blow of blower. If worn tube is found, then measure the thickness of tube with thickness tester. Also spot check and record tube thickness.

3. Check the rear enclosure tube at gas inlet section of low temperature superheater and economizer, and enclosure tube around the blow hole of blower.

The reduced thickness of tube should be less than 30% of tube thickness.

III Creep expansion inspection of tube at tube heat absorption area

1. With slide caliper or pipe caliper, measure the tube diameter of lead tube of low temperature superheater, outer tubes of separation platen superheater, outer tubes of rear platen and the first tube at flame-facing side of last stage superheater.

Note that before measurement, clean the ash deposits on the surface of tube and coke attaching to the surface of tube. During measuring, the slide caliper should

1. The expansion value of carbon steel tube of superheater is less than 3.5% of tube diameter.

2. The expansion value of alloy steel tube of superheater is less than 2.5% of

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be perpendicular to tube.

2. Macroscopic inspection of the appearance of tube.

tube diameter.

3. The appearance of tube has no obvious color variation.

4. There is no crack on the surface of tube, and the thickness of oxide skin should be less than 0.6 mm.

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IV Inspection and reshaping of tube row

1.Check the flatness and transversal pitch of tube row. If deflection or curving exist to tube row, find the reason of distortion or the deformation points. According to the reason, change the tube clip, restore the flatness of tube row. For serious deformed tube rows or single deformed tube deviate from tube row, the deformed section should be cut away to restore the origin pitch and flatness, and then recover by the aid of new tube. Change the transversal live connection board of deformed tube row, retighten the connection of platen superheater and horizontal location arm to restore the transversal pitch of tube row.

2. When replacing the tube clip or strap, electric weld or grinder may be used to cut the original parts. Note, do not damage the tube when carry out cutting. Before welding of fixing block of tube clip and strap, grind the crator left on the tube.

3.When replacing the tube clip, be sure not to weld the clip and tube together, similarly, the tube straps can not be weld each other when to be replaced.

4.The material of fixing parts should be the same to that of original parts.

1.The tube rows are flat, and transversal pitches are even.

2.The tube clip, tube strap and transversal live connection board of tube row are sound, without shedding, burning out, deformation, they are well fixed to tube row and can freely expand with tube.

3.Horizontal locating tube and platen superheater are well tightened, tube straps without droping off.

4.The material used for fixing part of tube clip is correct.

V Inspection of supervision sampling tube

1.The cutting position of supervision tube is to be determined and recorded by the chemical supervision personel.

2.Cut the supervision tube with special mechanical machine. The cutting point should be deviated from tube clip and the flex point of elbow for 150 mm. If such position is last sample one, then the replaced tube should also be removed. The length of supervision arm should be more than 250 mm.

The cutting position of supervision tube is correct.

There is no damage to the inner/outer wall of supervision tube.

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3.After the removal of supervision tube, the opening to the top should be plugged immediately. Position, direction of fluid and direction of gas side may be marked on the supervision tube.

4.Measure the thickness of sampling tube with thickness tester.

VI Tube replacement

1. Following the tube cut, use facing machine to make the divided edge of cross section.

2. Before butt welding, the pipe inner/outer wall should be ground until showing proper metal color. The length to be ground is 10-15mm in general.

3. Before the cut of new tube, visual inspection and pipe thickness measurement should be given to tube. For curved tube, the ellipticity of bending section should be carry out and given ball passing test, if neccessary. Purge the tube by the aid of compressed air before butt welding. For alloy steel tube, spectrum inspection should be performed before butt welding.

4.The welding technology of tube should meet the requirement of “Technical Specification of Electric Building Construction and Acceptance” “weld section of thermal power plant”(DLS007-92).

5.If number of replaced tubes exdeeds 50% of total, hydraulic pressure test should be carried out.

1.The divided edges of tube are smooth and flat. The angle machining of edges is the same with water wall.

2.New tubes have no traces of cracks, erosion, mechanical damages, the nagative tolerance of tube thickness should be less than 1% of tube thickness. The reduced amount of thickness of curved tube should be less than 10% of tube thickness. The ellipticity should be less than 6%. The ball passing test is qualified.

3.There is no dirt, foreign matter in the new tubes.

4.The flaw detection

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to weld seam following the weld is qualified.

2.4.6 Maintenance of radiant reheater

(Same as above: convection reheater)

2.4.7 Maintenance of platen reheater

(Same as above: convection reheater)

2.4.8 Maintenance of header


Inspection of header

1.Spot check the fillet weld of tube seat of header. Prior to check, grind the weld and header surface around the weld with electric wire brush until showing the original metal color. For tube fillet weld appearing exceptions, flaw detection should be performed.

2.For differential steel weld of tube-seat of header tube row, flaw detection should be performed after 100,000 h operation. Before detection, grinder should be used to polish the surface of and around the sides of weld.

3.The header joint weld can be ground or given flaw detection according to the requirement of metal supervision personnel.

4.The curveness of header may be measured with method of wire drawing. Prior to measurement, choose 6 equalized points along both sides of header. Mesure 6 values at such 6 points, select the

1.The fillet weld of tube seat has no cracks, the differential steel weld has no cracks.

2.The repair weld has no undercut.

3.The bending value of header will not exceed L/1000 (L is length of header), the allowed maximum is 5 mm.

4.The suspend derrick is even loaded, without erosion or deformation.

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minimum and record the direction of this value.

5.For weld appearing cracks, eliminate the cracks at first, and carry out repair weld. For alloy steel tube, preheat before weld and post heat treatment will be adopted.

2.5 Economizer

2.5.1 Technical specification of economizer tube, economizer header

No. Item Unit Quantity

1. Economizer

Quantity 1

Transversal gas flow mm 102

Along the flow direction mm 96.6


Effective heat absorption area (gas side) m2 3580


2. Header of economizer

Should be announced


Length m

around 17.2/15.7

Material SA106C

3. Water feed pipe-economizer to drum

Quantity 2

Nominal outer diameter mm 273

Material SA106C

2.5.2 Maintenance of economizer


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I Ash cleaning of economizer

1. During the ash cleaning, a group of induced fan may be started to keep certain negative pressure in the furnace and flue.

2.Upside down, purge and clean the ash deposit on the surface of tube and tube clip with compressed air.

3.The fouling in the ash hopper of economizer should be cleaned and drained.

4. Special processing measures may be worked out when clean ash with water.

1.There is no ash deposit on the surface of tube, and no foreign matter between tube row.

2.No ash deposit in ash hopper of economizer, ash hopper is free-flowing.

II Visual inspection of economizer

1. Measure with thickness tester the wall thickness of straight phase and bending section of the tube row at both sides of tube clip.

2. Measure the thickness of tube within the blowing range of blower with thickness tester.

3.Measure the thickness of suspended tube close to the tube row.

4. Before measurement of tube thickness, clean the ash on the surface of tube at the area to be measured.

5. Check the transversal pitches of tube row, eliminate the gas corridor.

1. The reduced thickness of worn or blowing-damage tube should be less than 30% tube thickness.

2. The tube rows are flat, and transversal pitches are even. No deformation or loose weld with tube clip.

3.The tube row is flat, without protruding or gas corridor.

III Sample of supervision tube

1. The cutting position of supervision tube is to be determined and recorded by the chemical supervision personnel.

2. Cut the supervision tube with special mechanical machine. If such position is last sample one, then the replaced tube should also be removed. The length of supervision arm should be

1. The cutting position of supervision tube is correct. The cutting point should be deviated from tube clip and the

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more than 250 mm.

3. After the removal of supervision tube, the opening to the top should be plugged immediately. Position, direction of fluid and direction of gas side may be marked on the supervision tube.

4. Measure the thickness of sampling tube with thickness tester.

flex point of elbow for 150 mm.

2. There is no damage to the inner/outer wall of supervision tube.

IV Tube replacement

1. Following the cut of tube, use facing machine to make the divided edge of cross section; Before butt welding, the pipe inner/outer wall should be ground until showing proper metal color. The length to be ground is 10-15mm in general.

2. Before the cut of new tube, visual inspection and pipe thickness measurement should be given to tube. For curved tube, the ellipticity of bending section should be carry out and given ball passing test

3. Purge the tube by the aid of compressed air before welding. When carrying out the welding, 3 mm gap should be left between tubes. The welding of tube should adopt all argon arc weld or technology of taking the argon arc weld as the backing, electric weld as the covering.

Note: Do not butt weld forcely. After the tack weld, not to strike with hammer.

4. Following the weld, carry out flaw detection to the tube.

1. The divided edges of tube are smooth and flat. The machining of divided edges refers to that of water wall.

2.The tube butt welding should refer to that of water wall.

3. New tubes have no traces of cracks, erosion, mechanical damagesThe nagative tolerance of tube thickness should be less than 10% of tube thickness. The reduced amount of thickness of curved tube should be less than 10% of tube thickness. The ellipticity should be less than 6%. The ball passing

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test is qualified.

4. There is no dirt, foreign matter in the new tubes.

5. The flaw detection to weld seam following the weld is qualified.

V Emergency maintenance of economizer

1. Following the stop of furnace and pressure relief, ventilation should be kept in the flue, but the water in the economizer should be kept.

2. Only when the temperature in the flue decrease below permitted maintenance temperature, personnel can enter the flue to find the leakage points. To find the leakage tube, water trace, voice and ash deposit of tube row or other methods may be referred to confirm the correct leakage section.

3. After determining the leakage position, report it to the operation personnel to drain the water in the economizer, and separate the economizer system.

4. For the maintenance, methods such as transfer tube section, short cut connection pipe, can be adopted. Repair weld may be used for tube which has reduced thickness less than 30% of tube thickness.

5.Following the weld, hydraulic pressure test should be performed.

6.The ash deposit on the surface of tube row should be cleaned before cutting. After the welding the tube, ash deposit and foreign matter in the ash hopper

1.The weld seam undergoing emergency maintenance have no leakage (after hydraulic pressure test).

2.There is no ash deposit, foreign matter in the ash hopper, which will keep free-flowing.

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should be cleared up and dredged.

2.6 Burner

2.6.1 Technical specification of burner

Oil burner: There are 8 HFO burner at each nose, i.e., 16 burners equipped for each boiler.The auxiliary steam of which the pressure stablized as 5.25 bar(g) render the HFO into atomizing state. Such steam is also used for burner purging. HFO will be ignited by high-energy ignitor. Each HFO burner is equipped with special flame inspector. Cooling air is supplied to burner and flame inspector through two independent special circuit. During the ceasation, the burner withdraw from the burner nozzle for about 330 mm, in order to avoid the affection of boiler radiation( prevent from burn out the burner). The total oil burning capacity (LHV base value) is 30% of BMCR fuel heat input value. Only adopting 12 burners can attain 30% of the burining capacity of BMCR.( two burners of each nose stop operation). The adjustment ratio of burner is 1:5. J11 type burner is used.

2.6.2 Maintenance of burner

Maintenance item


1. Inspection and repair of burners

1. Prior to inspection, coking and ash deposits in the nozzle and its outlet should be cleared up.

2. Check the surface wearing, surface split and weld cracks of structural parts for primary air nozzle.

3.Check the wearing and positioning conditions of divergent cone of primary air nozzle and pulverized coal dense/thin separation plate at outlet of nozzle.

4. Check the wear of pulverized coal nozzle at the outlet of primary air nozzle.

5. Check the appearance of secondary air nozzle.

6. Th local burn out, appearing in the nozzle can be cut and replaecd locally with plasma cutting machine. Divided edges should be machined for repair weld, with the edge angle of 90°. Between steel plates, there should be left 2-3 mm gap.

7. Local wears appear on pulverized coal dense/thin separation plate and nozzle can be

1.There is no coking, ash deposit in the nozzle and its outlet.

2.The primary and secondary nozzles are sound, without serious wear, burning out deformation, and cracks.

3.The divergent cone of primary air nozzle and pulverized coal separation plate and pulverized coal nozzle have no serious wear; Cone plate and separation plate are well fixed.

4.After local repair weld to nozzle, the surface is flat, weld is abreast

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bead welded. with steel plate.

5. Following local repair weld of the separation plate, the weld is flat.

2.Verification of burner nozzle swing angle

1.Before the verification of nozzle swing angle, use the chain hoist to swing nozzle at each corner, observing the swing circustances upside down, adjust the connection pole nut, to make the synchronous swing of nozzles.

2.Adjust the regulation nut of control mechanism, measure the level perpendicularity of each nozzle, position the nozzle to horizontal level.

3.Swing the nozzle to the largest elevation and inclination state, meauring the anlge value of them.

4. According to the real position of nozzle, check and calibrate the local indicator of swing anlge of nozzle.

1. The swing of nozzle is smooth. The swing of nozzles keep synchronous.

2.The tolerance after the calibration should be less than ± 0.5.

3.The actual swing angle of nozzle should be in conformity with the indiction of local angle meter.

3.Baffle of secondary air

1.Separate the baffle crank with the piston of pneumatic actuator, remove the crank, replace the seal material of baffle axis.

2.Lubricate the battle until obtaining the flexibility.

3.Operate the crank to examine the close position and utmost position.

4.Check the connection and fixing conditiono baffle and axis.

1.The switch of baffle turns smooth.

2.The position of baffle switch is correct.

3.The appearance of baffle is sound, and it is well fixed with axis.

2.7 Rotary Air Preheater

2.7.1 Technical specification of rotary air preheater

Designation Parameters of specification

Preheater

Manufacturer

Type

Unit/Boiler

Shanghai Boiler Works, Ltd.

Ljungstrom trisector

2 unit/boiler

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Rotor: Diameter

height

Heat transfer element: Material

Specification

10.318 m

1.88m

Primary section Cotton steel, Final section SPCC-SD

Thickness of Primary section, 1.2mm, final section, 0.6mm

Drive device

Main motor

Secondary motor

Reduction gearbox

Reduction ratio

Rotor speed: Main drive

Secondary drive

Lubricant

Y180M-4B3, 18.5kW, 1470r/min

Y160L-8B3, Dual output axil 6.08kW, 720r/min

SGW100

128.3

11.46r/min

5.61r/min

ESSO Spartan EP150 Industrial Super Gear Oil (ISO VG150): about 50L

Rotor bearing component

thrust bearing component

Guide bearing component

Lubricant

90394/710

3153172

ESSO Spartan EP680 Industrial Super Gear Oil (ISO VG680):Thrust beaing 160L; Guide bearing 25L

2.7.2 Maintenance of rotary air preheater


I Familiar with equipment

Learn the structure of air preheater, various parameter features and technical requirements.

Completely correct

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II Refer to files

1. Find out the operation circumstances of air preheater:

(1) Flaw, exceptions and emergency circumstances finding in the operation.

(2) Inlet/outlet gas temperature, primary, secondary air temperature at inlet/outlet.

(3)Air, gas resistence value of air preheater and the variation circumstances.

(4)The current value and current swing value of drive motor during the operation.

(5)Axial and radial runout circumstances of rotor during the operation.

(6)Operation circumstances of bearing component and lubricant system.

(7) Refer to test material and records, learn air leakage, ash clog circumstances of air preheater (an air leakage test may be separately performed prior to and after the maintenance).

2. Learn the maintenance circumstance about air preheater:

(1)Summary of last maintenance, air leakage materical and technical archive.

(2) Routine maintenance records.

(3) Ash cleanig, flushing conditions.

III Air preheater maintenance and technical, organizational measure plan preparation

Main contents are as follows:

1. Maintenance content and items.

2. Personnel organization and labor division.

3. Construction network schedule.

4. Working safety and health protection measure.

5.Quality guarantee and technical measures

6.Schedule of main facilities and tools, main

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IV Construction field requirement

1. Sufficient place should be supplied for maintenance of air preheater. Enough construction power supply and lighting for maintenance field, 12V lighting power supply should be ready for entry the preheater.

2.There should be setting mangement schedule.

3. Sufficient fire fighting facilities should be equipped.

V Safety The safety requirements of construction should comply with the provision of “Safe Operation Regulation of Electric Industry”(Thermal Machinery Section)”.

2.7.2.1 Maintenance of heat transfer elements

Maintenance item Workmanship and precautions Quality

spare part, accessaries and list of major materials.

7.Maintenance technology card

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standard

I purge of heat transfer elements

When the ash deposit is slight (it can be judged by experience according to the resistence increase of air, gas in the preheater, combining with attribute of ash that result from the coal being fired), while can not clear up the ash deposit only depend on the fixed ash blowing facilities, compressed air (with pressure 1.2-1.3MPa) can be used to purge the heat transfer surface, rotor surface and air, gas duct after the stop of air preheater. The purge work follows the sequence of from bottom to top, then from top to bottom. During the blowing, open all baffles of feed, induce fan, to allow the boiler keep certain negative pressure, keeping the good ventilation of air preheater.

II Washing of heat transfer element

1. Destination of cleaning the heat transfer elements: when the ash layer on the surfaced of elements is hard to purge, flush it with water that require certain quality demand.( usually, flush with alkaline water in 60-80 and rinse ℃

with water) The washing should be in the state of furnace stop, and having enough flushing and drying time.

2. Before the washing of heat transfer element, the following work should be performed:

(1) Verify the degree of ash depositing according to the maintenance records, operation conditions of air preheater.

(2)Choose water cleaning method according to depositing degree:

When the ash i① s soft and has high solubility, fixed washing equipment can be used to clean ( the matching equipment supplied by manufacturer or the flushing pipe from manufacturer served with water supply of power plant).

When the ash deposit is hard having low ②

solubility, some high pressure washing equipment

Whichever method is adopted, if the heat transfer elements are to be cleaned, they must be completely washed, and until the thorough dry of them.

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may be used for clean.

When the ash deposit is very hard or even being ③

the type of sintering, which is hard to clean with water, the heat transfer elements box may be disassembled for clean.

(3) Ensure the normal operation of drive device of air preheater.

(4) Ensure the normal work of flushing device and sufficient water supply.

(5) The boiler is stopped, and forced draft and induced draft fans stop operation. Cleaning heat transfer elements with single draft fan operating is not recommended.

3. Cleaning method

(1) Washing with fixed rinsing device;

The washing job is better to start when the gas ①

temperature at inlet of air preheater decreases to 200 ( to prevent the permanent deformation, the gas ℃

temperature is required below 200 ), and to ℃

terminate before 80 . ℃

Prior to cleaning, the ash in the h② opper of air preheater should be discharged.

During the flush, stop all the forced draft, induced ③

draft fan.

In the cleaning process, secondary drive device ④

should be employed to keep the air preheater run at low speed.

The temperature of cleaning w⑤ ater is preferred to be 60 ~80 .℃ ℃

If the deposits are acidic, defined amount of ⑥

sodium hydroxide or other alkaline substance (pH value >11 ) may be added to the water to increase the washing result.

During the washing, draining pipes must be ⑦

ensured to be free-flowing.

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III Inspection of heat transfer elements

Rinsing pressure and flow rate: water pressure at ⑧

primary secton > 0.52 MPa; the flow rater of each rinsing probe is about 150t/h.

Alternatively rinse the heat transfer elements at ⑨

primary and final section following the sequence of primary section to final section. When the rinsing pressure and water amount can meet the demand, the washing work at both ends may be performed at same time; discontinuned rinsing may also be taken to allow the softening of deposits.

In the process, chec⑩ k the draining regularly. When the pH difference is less than 1, or when the rinsing water is common water, the pH value of draining water is within 6-8, stop the washing.

Completing the rinsing, close the water supply, ⑾

after making sure the valve has no leakage, close the draining valve.

After the rinsing work, immediately carry out the ⑿

job of drying the heat transfer elements. During the drying, keep the rotating of air preheater, totally stop the forced draft fan and induced draft fan, fully open the air, gas baffles of inlet/outlet of air preheater. Adopting natural ventilation, dry the heat transfer elements with residual heat of boiler and air ventilation. It must be make sure that all the heat transfer elements is completely dried.

The rinsing ⒀ result of heat transfer elements. Draw out some typical heat transfer elements from each layer. Take them down to check whether every surface of the elements has ash deposit and sediment or not. And ensure the completely dry of them, i.e. being qualified. Otherwise, they are more inclining to accumulate ash.

(2) Washing with special rinsing machine: when regular rinsing machine is hard to clean the ash deposit, special rinsing machine may be used to washing the equipment after cooling of boiler.

Choose suitable rinsing pressure and water flow ①

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IV Replacement of heat transfer element

rate according to actual conditions of ash deposit.

Using common water or alkaline water of which ②

the pH>11.

If the cleaning quality or the operation safety can ③

not be ensured inside the air preheater, the heat transfer elements boxes should be lifted from the sector cell to washing outside, until they are clean.

If rinse with alkaline water (pH>11), common ④

water may be used for washing the equipment again.

Following the rinse, pay attention to the ⑤ drying of heat

(3) Heat transfer element cleaning after disassembly.

When the ash deposit on heat transfer elements ①

is sintered and hard to clean with water, the heat transfer element boxes should be disassembled to clean the surface deposit with mechanical method and then reassemble them.

When the number or shape of heat transfer ②

elements can not be restored to the same of origin, reasonable heat transfer elements should be arranged perfectly according to the design of manufacturer. Do not change the gaps between heat transfer elements and the number of them, to avoid affecting the performance of air preheater.

(4)The inspection of heat transfer elements should include inspection of heat transfer elements and the boxes of them, which are as follows:

Inspection of erosion, wear and deformation of ①

heat transfer elements.

Check the wall thickness of heat transfer ②

elements, measure them if necessary.

Inspection of heat transfer elements combination, ③

the corrugated plates and position plates should keep the correct geometry shape; the corrugated plate and position plate should be compressed.

The replacement of heat transfer elements must ensure the correct geometric shape and quantity combination.

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Except the special design provision that some nature empty space exists, there should be not any looseness. Otherwise corrugated plate or position plate should be considered to plug in.

Inspection of erosion, wear, cracks, shedding, ④

deformation of frame of heat transfer elements. Put emphasis on the check of cracks and fatigue conditions of welding parts of such frames. If necessary, repair the frames.

Inspection of support frame of h⑤ eat transfer elements. Support frame have no deformation, serious wear, no cracks on the weld seam.

Inspection of the gaps of heat transfer element ⑥

boxes edges and sector bin edges. Such gaps should comply with the design requirement, i.e., less than 3 mm.

(5) When one of the following circumtances happens, the heat transfer elements should be replaced( as the case may be, locally or totally):

When the erosion or wearing of heat transfer ①

elements is serious, affecting the heat transfer result or operation safety.

Whn the wall thickness of heat transfer element ②

reduced to 1/3 original thickness.

seriously blocked, and can not be purged.③

2.7.2.2 Maintenance of driving device

2.7.2.2.1 Maintenance of primary reduction gearbox


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1. Drain the lubricating oil and check it; the disassembly of shaft series parts should be limited by clean and inspection, try to reduce the disassebling work; if it is need to take down parts, the assembling marks should be made; in no way should the cotton waste be used for clean parts.

1. The quality of gears, shafts and bearings should meet the provision of related standards.

2. After the assembly of shafts, the end face dislocation of two engaged gears at the direction of face width should not exceed the provision in Table 1.

Table 1 End face dislocation of two engaged gears at the direction of face width(mm)

Face width( width of rim)

End face dislocation

I Disassembling clean and inspection of all parts

<50

≥50-150

≤1.5

≤2.5

II Inspection of oil level gauge

1. Wash the oil level gauge with kerosene.

1. Oil level gauge has no damage, oil level shows clearly, the mark of oil level is correct.

III wash and inspection of gearbox case

1. After the washing of case, wipe the case with white cloth, and stick the foreign matters with adhesive object. Prior to assembly, the inner space of case should be kept clean. Check with 0.05 mm filler gauge the gaps of joint surface that case seat and cover combined freely.

1. The case has no cracks and other flaws, and is clean; the case has no leakage; when the case seat and cover combine freely, the plug depth should not more than 1/3 of joint surface width. After compress the case seat and cover, the seal of reduction gearbox must be tight, without leakage or penetration of oil.

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IV Maintenance of hydraulic coupling and Replacement of shaft gland

1. Check if the inner oil filling amount meet the design requirement of manufacturer, and examine or replace.

2. Check the locking of screws.

3. Determine whether or not to replace, according the the oil penetration of shaft gland.

1. The shaft glands are well without flaw.

V Replacement of lubricating oil

1. Before oiling, consider whether or not to filter oil according to the quality of oil.

1. Oil quality meets the requirement of manufacturer.

VI Inspection of base and screws of base

1. The base has no cracks, the screws have no loose.

VII Assembly of whole machine

1. During the assembly the gear backlash and axial clearance of bearing should meet the requirements.

2. Adhesive must be add to the joint surfaces, baffles of upper/lower case, joint surfaces, plug screw, oil scale which adopt the paronite as gasket. Surfaces are to cleaned before coating.

1. The gear backlash is 0.21-0.40 mm; the axial clearance of bearings through which the shaft protrude may be left at the lower end, the value is 0.10-0.20 mm.

The axial clearances of shaft I and shaft VII are left to the side close to motor, the value is 0.05-0.13 mm; that of shaft III is 0.06-0.15mm ； the clearance of other shafts may be 0.05-0.13 mm.

2. After finish the assembly, run the machine with hand, the direction should be correct, smooth and easy, without clogging(the numbering of shafts based on manufacturing drawings).

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VIII Trial operation

1. Following the assembly, no load running must be carry out in the direction of working, the normal running time should be more than 2h.

2. Load test, the time is 50h.

No load running should meet the following requirements:

(1) The speed regulating mechanism is flex, accurate and reliable.

(2) The running is stable and regular, with impaction and exceptional noise.

(3) Various sealed section, joints have no leakage, penetration.

(4) the fastening parts, connection parts have no looseness.

(5) The temperature rising in the oil tank is not more than 35 , that of bearing ℃

not more than 40 , the ℃

max temperature of bearing not more than 80 ( or meet the ℃

requirement of manufacturer). Comply with the requirements of manufacturing specification.

2.7.2.2.2 Maintenance of overrunning clutch

Washing after disassebly, check the completeness, lubrication and sealing conditions of various parts. The clutch should be stable and reliable, and can swiftly, completely on-off.

2.7.2.2.3 Maintenance of shroud band driving device


I Engagement inspection of drive gear and output shaft

1. If disassembly is necessary, various joint surface should be thoroughly washed.

1. the contact surfaces between drive gears, shafts, bushes are smooth, without burr,

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stablizely matched.

II Inspection of drive gears

1.Check the cracks, perform the penetrant inspection if necessary.

1. The drive gears have no missing tooth or block, the gear roots have no cracks; replace the gear when the wear amount arrive at 1/4.

III Inspection of drive shroud band

1.Measure the wear amount of shroud band pin with slide caliper; measure the radial runout at the end of shroud band with micrometer.

1.The welds of drive shroud have no cracks, the fixing screws have no break, looseness, shroud band pin without looseness or falling off; replace the pin when the wear amount arrive at 1/4; the radial runout value should in line with the regulation of manufacturer.

IV Inspection of engaging conditions of drive gear with shroud band pins

1. Rotate the rotor, find out the most protruding point of shroud band pin( at the direction of rotor diameter), measure the dimension c ( may use the filler gauge), also find the axial most protruding point, measure the dimension of a and b; if necessary, adjust with pads to ensure the full engagement of drive gear and shroud band pin.

1.As shown in Fig. 2-9, the fixing gaps between shroud band pin and drive gear should meet the regulation of equipment technical files: Min. a is 13 mm; Min. c is 20 mm.

2. The drive gear and shroud band pin is in line contact, the axis of drive gear must parallel to the axis of shroud band pin.

V Inspection of drive gear enclosure

1.the enclosure of drive gear must be sound and secure.

2.7.2.2.4 Maintenance of thrust bearing component and guide bearing component


I Measure and adjust the levelness of bearing block

1.The measurement of levelness of bearing block should be carried out at the direction of end face diameter of the seat.

1.The error of bearing block levelness is not more than 0.05mm.

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Record the data before and after the maintenance.

II Disassembling Maintenance of bearing component

1. Prior to disassembly of bearing component, drain the lubricating oil in the seat; Implement the temporary support and fixing work of the rotor, keep the level of rotor when supports it; perform various record work before the disassembly; during the performance of bearing component maintenance or maintenance of other items of air preheater, measures should be taken to prevent the current flowing through bearing, avoiding the electric corrosion at rotating objects.

2. Inspection of fixing bolts, nuts and washers of bearing block:

The screws, bolt hole and washers should be numbered for the future reassembly that mount parts with corresponding number; during the assembling, anti-seize paste should be smeared between screw and nut.

3.Inspection and washing of bearing block Wash the bearing block with kerosene, and stick foreign matters with adhesive object, and wipe it with lint-free clean soft cloth.

4.Inspection and washing of rolling bearing If the bearing is needed to remove, hydraulic oil pump may be used to remove with compression; the bearings

1. The fixing screws, nuts have no looseness; bolts have no twisting, screws and nuts have no damaged tooth; washers is tidy, without cracks; bolts, nuts and washers should be clean; when all the nuts is fastened, the washers should be jammed together. Use 0.05 mm filler gauge to check whether or not exist gaps.

2. The bearing block has no cracks, burr, groove trace, rust, oily dirt, foreign matter; the joint surface of flange is purged clean, without burr. There is no shedding, falling off, wearing, color variation due to overheat, rust, crack, or breaks; the clearance of bearing should meet related requirement of standard.

3. The surface of rotary disc is smooth, without pitting, pinhole porosity, cracks, groove trace; the balance weight and position pin is well.

4.The surfaces of shaft, connection sleeve and locking cover have no cracks, burr, groove trace, color variation due to

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should be put on the smooth plane covered with soft cloth for maintenance; check the gap of bearing with method of pressing lead wires.

5. Wasing and inspection of shafts, connection sleeve, locking cover Remove the shaft and connection sleeve adopting the pressing of hydraulic oil pump.

6. Check the fitting conditions between bearing, connection sleeve, shaft and locking cover.

7. Inspection of thermal temperature measurement point device.

8. Check and washing of oil level gauge: wash with kerosene.

9.Change the lubricate oile: filter the oil before oiling.

10. Sealing inspection of bearing block: Check the joint surface of the flange of bearing block with 0.05 mm filler gauge.

overheat; the screws of locking cover has no fracture; there is no relative motion between shaft, connection sleeve and locking cover. Regulate the gap between bearing and connection sleeve, gap between connection sleeve and shaft, the fixing of locking cover, tight tension of screws should comply with prescription of manufacturer.

5. Oil level gauge has no damage, oil level shows clear, the dimension of level is correct. Following the completing of bearing component maintenance, immediately fill in lubricating oil compling with requirement to the top level.

6. When the flange of bearing block freely combined, the depth that the filler gauge plugs into the joint surface should not more than 1/3 of total width; after pressing of bearing block and bearing cover, the seal must be tight, without leakage or penetration of oil.

2.7.2.2.5 Maintenance of rotor and air, gas ducts

With respect to air preheater of which the drive elements rotate, the rotor refers to the sector bin in which mounted the heat transfer elements forming by the radial baffle and transversal baffle. When the air preheater is running, it rotates with the heat transfer elements.

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Maintenance of rotor and air, gas ducts:


I Measure the center barrel and the levelness of fitting parts of end shaft

1.Perform the measure with precision level gauge at the header plate of center barrel or the shaft of support end; if the permitted levelness is exceeded, adjust the direct bearing seat and check again.

1.The error of levelness is not more than 0.25 mm/m.

II Measure the roundness of rotor

1. Measure the roundness of upper/lower panel of shroud band with dial gauge.

1. The difference between maximun and minimum ≤ 4mm.

III Measure the deviation of upper/lower end plate of rotor

1. Use dial gauge to measure the deviation of upper/lower end plate of rotor

1.The deviation value ≤4 mm.

IV Measure the concentricity deviation of rotor with casing

1. Use dial gauge to measure the concentricity deviation of rotor with casing.

1. The deviation value ≤3 mm.

V Inspection of rotor welds

1. Visual inspection, if necessary, perform penetrant inspection to welds.

1. The welds between radial baffle and transversal baffle, welds between radial baffle and center barrel have no crack, welding beading, welding flaw, and ensure that the welds have enough strength.

VI Check connection screws between sector bins of rotor

1. The connection screws have no looseness, no fracture.

VII Inspection of sector bins of rotor

1. The sector bins have no deformation. The radial baffles and transversal baffles form the sector bin grid, the dimension deviation of grid edgs is

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±6 mm, diagonal deviation is not more than 10 mm; the surfaces of baffles are smooth, without burr and welding beading.

VIII Check the gap between rotor outer wall and inner wall of gas duct

1. Rotate the rotor, take 3-4 points on the inner wall of gas duct, measure the gap value.

1.Such gaps must be even.

IX Inspection of the air duct, support frame of gas duct

1.The support frame which is seriously worn and eroded must be replaced; the anti-wear tiles are firmly welded; those tiles worn more than 2/3 should be replaced.

2.7.2.2.6 Maintenance and adjustment of sealing devices


I Inspection and adjustment of sealing devices

1.Measure the three-direction (radial, peripheral or bypass, axial) gap values before the maintenance.

2.Check of sealing strips.

3.Inspection of T-steel.

4. Installation and adjustment of radial sealing strips: perform the gap adjustment by the aid of sealing component having been aligned; detailed steps may be in accordance with the specification of manufacturer.

5. Installation and adjustment of axial sealing strips ( see Fig. 2-10): Regulate the gap by the aid of aligned axial sealing component, detailed steps refer to the specification of manufacturer.

6. Installation and adjustment of peripheral( bypass) sealing strips ( see

1. The sealing strips should be perfect, those that seriously worn, deformed, eroded should be replaced.

2.The roundness deviation value of T-steel may not more than 1.5 mm. The assembling sequence and installing direction of sealing strips, gap compensation strips and pressing plate should be correct, the screws should be tightened; the sealing clearance and the specified

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Fig. 2-11, take trisector as an example); When measure the value of a and b, place the gap gauge on the min radius section of T-steel, rotate the rotor, measure and record every 30°; measure value of c and d at the same time.

7. Inspect seal of center barrel.

8.Check stationary seal.

deviation value should not be more than 0.5 mm.

3. As shown in Fig. 2-10, the error of values with specified value is 0.5 mm.

As shown in Fig. 2-11, the error of values with specified value, 0.5 mm for a and b, 3 mm for c, d. Such values may meet the design requirement. The stationary seal at various places should in line with the design requirement.

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II Inspection and maintenance of air leakage control system

1. Prior to maintenance, cut the power supply following the reset of sector plate.

2. Clear up the ash deposit and foreign matters around the sensors and actuator, keep tidy around sensors and actuator.

3. Check the sector plate.

4.Inspect the flatness of the end flange of hot end of rotor.

5. Adjust the clearance of the radial sealing strip and sector plate to meet the technical requirement. The adjusting method is as follows:

(l) After the preliminary fix (but not fastening) of radial sealing strip and flange, adjust the distance from every sealing strip to flat ruler by means of aligned sealing components and sealing ruler, allow it meet the technical requirement of the distance from radial sealing strip and sector plate, then tighten the radial sealing strips.

(2)Make the upper edge of radial sealing strip as the base, adjust the levelness and height of each sector plate, to allow the distance of radial sealing strip and sector plate meet the technical requirement.

5. Inspect and repair the detector and sensor. When the thickness of sensor petal is less than 3 mm, replace it.

6. Correct the detector to make it match with the exterior indication and to be correct.

7. Perform maintenance and repair to actuator devices.

8. Following the completion of maintenance of automatic control system, such system should attain the design requirement after commissioning.

1. The sector plates have no deformation, crack, the surfaces have no unevenness.

2. The rising/dropping of sector plates should be smooth, without clogging, and can reach utmost limited positions.

3.The fixing, adjusting devices of sector plates should be in good order.

4. The planeness value should not be more than 0.5 mm, the flange surface should be smooth.

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III Quality standard for maintenance and adjustment of sealing device

1. From the startup of boiler to the full load operation, the sealing devices should not occur serious friction.

2.7.2.2.7 Maintenance of various secondary systems


I Lubricating oil system The maintenance of lubricating system should include maintenance of oil tank, oil pump, oil filter, heat exchanger, pipes, valves, thermometer, pressure meter.

1. Clear up the ash, foreign matter around the lubricating system.

2. Disassembling oil pump for maintenance, when changing new pump or motor, pay attention to the correct rotation direction of them.

3. Inspect the ground screws of oil pump and motor.

4. Disassemble the oil filter for washing, replace filter strainer. When disassemble the oil filter, also check if the reversing valve of strainer can be closed tightly; Check and wash the by-pass safety valve, and verify or adjust the pressure.

5. Disassembly inspection of and washing oil cooler, and perform the hydraulic pressure test.

6. Inspection of various valves.

7. Check, wash the oil tanks, oil pipes, eliminate leakage.

8. Washing and inspection of oil scale, calibrate correctly.

9. Oiling, first filling to the top. When the circulating oil pump put into operation, the oil level may drop, observe the change of oil

1. The switching of various valves of pipes is smooth, without leakage.

2.The joints of oil pipes have no leakage.

3.The indication is clear, correct.

4.Lubricating oil and strainer may be change at least once per year.

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level, and filling the system in time.

II Maintenance of fire fighting system

1. Arrangement check of hose nozzles.

2. Check the wearing, erosion and blocking conditions of fire-fighting pipe and nozzles, and repair.

3. Check the free-flowing of fire-fighting system, which should have no leakage.

4. Maintenance of the valves of fire-fighting system.

5. To prevent of the block of hose nozzles, heat-resist cellucotton plug or the anti-block plug in other forms may be considered for installing in the exit of nozzle.

1.The hose nozzles should evenly cover the heat transfer elements at gas side.

2. The nozzles, of which the worn thickness exceeds 2/3 of total must be replaced.

3. Make certain that various valves are smooth, without leakage.

III Maintenance of ash blowing system

1. Maintenance of steamed ash blowing system: Currently, the systems provided by manufacuturers are all steamed ash blowing ones. The whole system includes blower, pipes, valves, instruments and ash-blowing control system. The superheat degreee of steam should be controlled strictly, and may be put into use and maintained according to prescription. Following are maintenance contents:

⑴ Maintenance of soot blower

① Check the blowing damage, erosion, blocking deformation condition of barrel of soot blower and nozzles, and repair;

② Inspection and repair of drive devices;

③ Change lubricating oil;

④ The soot blowing barrel of retractable soot blower is normal;

⑤ Change the sealing packing, eliminate leakage.

⑵ Inspect steam pipes, eliminate leakage,

1. Make sure the steam blower has no clogging during operation.

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check the steam pipe entering the air preheater. ① The draining device at the lowest section must be free-flowing.

② Check and repair of various supports and hangers and their insulation.

③ Maintenance of pressure reducing valve, setting the pressure.

④ Maintenance of safety valve, setting the pressure;

⑤ Calibrate the pressure gauge and thermometer;

⑥ Maintenance and commissioning of soot blowing control system.

IV Maintenance of alarming system

1. Air preheater fire alarm.

2. Rotor stop rotating alarm

3. Bearing temperature supervision system.

1.When the infrared measuring point attains 150-200 ℃ , the annunciator alarms.

2. When oil temerature of support bearing reaches 71.1 ℃ , alarm.

3. When oil temperature of direction bearing reaches 82.2 ℃ , alarm.

V Miscelleneous 1. The air preheater should be equipped with seal-type sight glass

2. The holes and doors are in good condition, their closure is tight.

3. All the platforms, handrails and railings are good.

4. The insulation is in good condition.

1. Ensure the sight glasses and manholes are tightly sealed, without leakage.

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5. Various beams, posts are intact.

2.8 Desuperheater

2.8.1 Technical specification of desuperheater

Two water spray desuperheater stages are arranged for superheater system. The first stage desuperheater is arranged at the connection pipe between low temperature superheater and separation platen superheater, the nozzle adopts multihole flute-form tube structure, material 12Cr1MoV. The second stage water spraying desuperheater is arranged at the inlet connection pipe of last-stage superheater, adopting multi-hole flute-form nozzle, material 12Cr1MoV.

2.8.2 Maintenance of desuperheater


I water spraying desuperheater of superheater

1. Clean with wire brush the rust and fouling on the surface of and around the position screws of inner bushing and spraying pipe of desuperheater, and welds of outer wall spraying pipes and fixed bushing of desuperheater header, until showing the origin metal color, and perform penetrant inspection to such welds.

2. After operating for two overhaul circles, the spraying pipes, sleeves inside the desuperheater should be checked with endoscope.

3. When spraying pipes are to be replaced or multihole flute-form nozzles are to be checked, the connection weldd of spraying pipe and fixed sleeve may be cut, and cut the welds of position screws, unscrew the position screw, at last, cut the spraying pipe and take out. Prior to installation of spraying pipe, the direction of spraying hole should be marked on the top of spraying pipe. During the installation, it may be fixed with position screws at first. After confirm the correct direction of

1. The fastening screws of inner bushing of desuperheater, and spraying pipes, position screws and welds of outer wall of desuperheater header have no cracks.

2. The welds of feeding pipe and fixed bushing of desuperheater have no crack.

3. The surfaces of inner sleeve of desuperheater have no erosion, crack, and is well secured, the surfaces of spraying pipe have no crack, erosion.

4. After replacement of spraying pipes, the direction of spraying hole should be correct, the welding of pipes should meet the requirement of “Technical Specification of Electric Power Building Construction", the welding section of thermal power

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multihole nozzle fix the postion screws and butt welding edges with spot welding. Then weld them separately. At last weld the spraying pipes and fixed bushing. Before weld, grind the inner/outer wall at both ends of pipe, the ground length may be 10 to 15 mm. The welding will take the technique of with argon arc weld as backing and electric welding as cover, heat treatment should be performed after welding.

plant (DL5007-92).

II Water spraying desuperheater of reheater

1. Remove the flange screws and position screws of spraying pipe, take out the nozzle.

2. Inspect the hole diameter of nozzle and welds of it.

3. Check the inner wall of inner sleeve of the desuperheater with endoscope.

4. Prior to replacement of nozzle, its direction mark should be made. During the replacing, the joint surface of flange should be tight, the flange screws are even loaded.

1. The nozzles have no blocking, welds of them have no crack.

2. The surface of inner sleeve of desuperheater has no crack.

3. After replacement of nozzle, its direction is correct, the joint surface of nozzle flange is well sealed.

2.9 Boiler Water Circulating Pump

2.9.1 Technical specification of boiler water circulating pump

Designation Specification Parameters

Type Oil seal free circulating pump

Work medium boiler water

Quantity per boiler 3 units

Number of operating pumps 2 units

Design pressure 2. 10MPa

Test pressure 3. 15MPa

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Design temperature High pressure cooling device: 176℃

Medium temperature Hot state:359 C Cold state: 20℃

Flow rate 2182mJ/h

Maximum temperature difference between pump housing and boiler water

55K

Input power of pump Hot state:121.5kW Cold state: 225.5kW

Low pressure temperature cooling water Inlet: 37.8C Outlet: 45.5℃

Low pressure cooling water flow rate 5M3/H

2.9.2 Structure of boiler water circulating pump

The Boiler water circulating pump is a single-in-dual-out single stage centrifugal pump in the circulation of boiler water. It consists of wet-type stator asynchronous motor and connected pump component, pump housing and heat exchanger for cooling motor. Thereinto, the inlet and outlet of pump housing are connected to downcomer system of boiler. In the cavity of pump, there is an closed type diffuser driven by key and a mixed-flow impeller which is mounted on the extension end of motor shaft. In the impeller and diffuser, wear-resist rings are equipped. The motor is hanged on the pump housing, the motor and pump housing are connected with high pressure sealing flange. To reduce the heat transfer from pump body to motor, the cross section at the connection part of motor and pump is very small, such part is called neck. The motor casing and pump are intergrated via the connection of neck. Separation plate is installed at the connection section of pump and neck, to prevent the boiler water to the inner of motor. The heat exchanger is arranged besides the motor. It forms a cooling circuit together with motor.

2.9.3 Maintenance of boiler water circulating pump


I Removal of motor of boiler water circulating pump

1. Before the removal, number the screws, nuts of the connection flange of pump/motor and pump housing, and mark corresponding number on the pump housing; Select 6 corresponding equalized points at the two connection flanges, measure and record the distances between 6 equalized points.

2. Mount two chain type lifting device or rigging on the lifting eyes at both sides of pump/motor. Before the loose of nuts of fastening screws, pretight the pump/motor with two lifting devices. Note: Each lifting device should be able to bear

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all the weight of pump/motor.

3. Remove the high, low pressure cooling pipes connected to cooler of pump/motor, and block the exit of pipes.

4. Install heating rod or hydraulic tension clamp for loosing the flange screws.

5. When heat with the heating rod, the temperature can not exceed 300℃, the heating time can not exceed 50 min. during the heating process, tap the nuts with little hammer until the looseness of screws, and can unscrew the screws with hand, then stop heating.

6. When use the hydraulic tensioning device for screws, firstly check the oil pump, which must be well for use.

7. The pressure increase of oil pump should be performed slowly. The pressure that each screw bears should be uniform. The pressure rise of oil pump can not exceed the limited the working pressure. Use a little hammer tap the screw at each sequencial pressure value, until all the screws can be loosen with hand, then stop pressure rising.

8. When all the nuts to the connection screws of flange are removed, synchronously operate the two lifting devices to make the pump/motor to apart from the pump housing, and remove the pump/motor from the pump housing. Note: During the removing, keep the plane of pump/motor in level, until the diffuser apart from the pump housing.

9. Following the removal of pump/motor, it should be put at clean maintenance place in horizontal position. Note: Do not place the weight at draining valve or line connecting cover.

II Disassembly of 1. Prior to the removal of diffuser and impeller, 1. The key way at shaft end and the key

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pump component they should be marked.

2. Dismount the hex bolts fixing the diffuser on the motor, remove the diffuser.

3. Unscrew the jammed screws or nuts of impeller, draw out the impeller from the shaft. Then take out the screws of anti-wear ring of impeller and the anti-wear ring. Note: after remove the impeller, immediately use a maintenance nut to protect the thread of shaft.

4. Clean the fouling on impeller, diffuser and anti-wear ring with wire brush, brush or compressed air, and inspect their surfaces.

have no damage.

2. There is no fouling on the surfaces of diffuser impeller and blade.

3. The reduced wall thickness of worn trace of diffuser and impeller is less than 30% of wall thickness.

4. The root section of impeller has no crack, the hardened surface of anti-wear ring is smooth without cracks.

III Inspection of sealing face, flange screws, nuts of pump housing.

1. Clear up and inspect the sealing face of pump housing flange. If blowing damage or erosive pitting exist on the sealing face, grind them.

2. Wash the flange screws and nuts with kerosene, also randomly select two screws and nuts for penetrant inspection.

1. The sealing face of pump housing flange is flat and smooth, without blowing damage, crack, erosion.

2. The threads of flange screws and nuts have no break, burr.

3. The elongation value of screw is less than 0.3 mm.

IV Installation of pump component and pump/motor

1. Put the anti-wear ring on the baffle of impeller and fix it, remove the thread protective nut on the shaft end, mount the impeller key, place the impeller onto the motor shaft. Note: After complete the installation of impeller, measure and adjust the concentricity of impeller and motor shaft, anti-wear ring, the gap of motor shaft of impeller, distance form impeller end face to main flange plane at motor side.

1. The top gap of impeller key should be less than 0.25 mm.

2. The eccentricity of impeller is less than 0.05 mm.

3. The distance from end face of

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2. Put the diffuser on the motor bolts, align with the position marks made during removal, fasten with screws.

3. The lifting of pump/motor should be slow, and keep the level when put the diffuser into the pump housing. When the motor side flange reach the bolts of pump housing flange, stop raising. After all bolts align with holes on the flange, lift again until the two flange sealing faces contact. Then pretight with nuts. After that, make corresponding position marks on the nuts and screws. Note: seal gasket of flange should be replaced. Coat molybdenum disulfide on all screws and nuts and flanges.

4. Install heating rod or hydraulic tensioning devices for tightening the flange screws.

5. The heating should be carried out piece by piece. Evenly distribute 8 items /piece. Heat untile each nut can turns one whole circle( 24 scale intervals), and then cool down. Heat another 8 bolts, until each nut can turn 2.5 scale intervals.

6. In the employment of hydraulic tensioning device, the tension pressure of each bolt should be identical, tighten each nut at every sequential pressure value.

7. Following the fastening of nuts, select 6 opposite bisection points at circumferences of two flanges, and measure the distances of two flanges.

impeller to flange face of motor side should have no deviation.

4. During the installation of pump/motor, the diffuser and screws and pump housing should have no collision; after installation, seal face is well contacted and tight. The pump has no leakage after putting into operation.

5. The distance error of two flanges should be less than 0.06 mm.

V Maintenance of heat exchanger

1. Remove the connection screws of lower/upper side end cover flanges of heat exchanger, take down the end cover.

2. Clear up the dirt on the surface of pipe plate, and carry out flaw detection to such surface.

3. Remove the fastening screws of filter

1. The pipe plate has no dirt, thread.

2. The filter screen has no damage, dirt.

3. No leakage during the hydraulic

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screen, reverse blow the screen with compressed air , and wash it in clear water.

4. Replae all sealing parts.

5. Disassembly of high pressure water filling valve, replace the seal strip.

pressure test.

4. The sealing strip of high-pressure water filling valve has no damage.

2.10 Hydraulic Pressure Test of Boiler

2.10.1 Classification of hydraulic pressure tests

Hydraulic pressure tests are divided into two kinds: one is normal hydraulic pressure test, test pressure is working pressure of drum. Another kind is at when the boiler stopped for 1 year and need restore the operation; or when the structure of boiler underwent major reforming, or pressure equipment or system underwent major exceptions, the changed heating area exceeding 50%, the drum or lower drum has major reforming; or when the safe reliability of pressure equipment is doubted according to operation conditions the overpressure test is needed. The test pressure is the value provided by manufacturer. If demand overpressure test value, then take it according to 1.25 folds of the design pressure of drum.

2.10.2 Qualified Criteria of hydraulic pressure test

1) Pressure drop in 5 min: less than 0.5Mpa for primary system, less than 0.25Mpa for secondary system;

2) There is no leakage trace of any beads or water fog on the metal wall of pressure barrier parts and welds.

After visual inspection, the pressure parts have no obvious residual deformation.

2.10.3 Conditions of hydraulic pressure test

After the maintenance of boiler, to verify the quality of pressure equipment, and ensure the boiler can be started in one time and the safety operation of pressure equipment, such equipment should be given hydraulic pressure test following the maintenance of boiler heating surface and steam and water system outside the boiler.

Normal pressure or overpressure test can be carried out only after the following works have been finished:

1) The maintenance of boiler heating area and steam and water system outside the boiler are completely finished.

2) Valves of steam and water pipes of boiler have been mounted, electric actuators have been calibrated.

3) Maintenance of electric water feed pumps complete.

4) Main steam pipes are isolated from HP cylinder of ST, withou leakage.

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5) All pressure meters have been calibrated.

6) The local water gauge for drum and electric connection point water gauge have been mounted and calibrated.

7) The TV camera for local water gauge of drum is normal.

8) The support/ suspension derricks for four kinds of pipes is ensured to be safe, and have been reinforced when necessary.

2.10.4 Hydraulic pressure test


Preparation work before hydraulic pressure test

1. Fill out applicant sheet of hydraulic pressure test. After the countersign, it should be sent to the shift chief-operatorThe applicant sheet may include: (1) Hydraulic pressure test time

(2) Test range.

(3) Test pressure.

(4) Safety and protection measures.

(5)Exceptions of equipment within the hydraulic pressure test range, exceptions completion report and system diagram after exceptions.(6) Signature of discipline principal and countersign principal. If it’s overpressure test, the signation includes that of General Engineer.

2. According to range of hydraulic pressure test and the pressure of test, such equipment as follows should be protected or separated:

(1) Safety valves. (2) Electromagnetic relief valves.

(3) For supports and hangers of main steam pipe, if the permitted load is not clear, then chain hoist should be hung to the pipes or supports and hangers and give pretightening, in order to avoid the overload of supports and hangers.

3. Set out the technical measures and organizational measures of hydraulic pressure

1. The hydraulic applicant sheet is correctly filled, without missing.

2. Protection plates of safety door are mounted without omitting.

3. Organizational measures and safety measures are perfect. Clearly specify the director, coodinator, inspector and test steps, notes.

4. The needle of expansion indicator is adjusted to zero.

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test.

4. Check the guidance device of boiler expansion and expansion indicator.

II Hydraulic pressure test

1. Injecting water into boiler until the closure of air gate.

2. Increase the pressure of boiler to 1MPa. Carry out preliminary inspection to various systems by inspectors.

3. If no exceptions is found during the preliminary inspection of equipment and systems, inform the operator to continue the pressure increase. When the pressure increase to 4MPa, stop pressure increase, and keep that pressure. Tighten the screws of drum manhole and lower drum manhole by the maintenance personnel. Note: During the pressure increasing, the increase rate should be less than 0.6 MPa/min.

4. After the tightening of manhole screws, inform the operator to increase the pressure to test pressure and keep it. Inspect the pressure equipment and systems by the maintenance personnel.

5. Record the values of various expansion indication pannel.

1. Pressure pipes and weld seam have no leakage.

2. Pressure valve is free of leakage.

3. Manholes of drum and lower drum have no leakage.

4. Pipes have no residual deformation.

II Overpressure test

1. The same as normal hydraulic pressure test.

2. As the test pressure increase to 5532？ , inform the operation personel to stop increasing the pressure, and keep that pressure.

3. The maintenance personnels enter the field to check various pressure equipment and systems.

4. After confirm that the equipment and system have no exceptions and maintenance personnels withdrawn from the site, inform the operation personnel to increase the boiler pressure to test value, keep the value for 20 min, and then decrease the pressure to normal work value.

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5. Connect the equipment that does not receive overpressure test to the system.

6. The maintenance personnel enter the site again to inspect pressure equipment.

7. After ensure that the equipment has no exception, inform the operation personnel to relieve the pressure. Note: During the overpressure test of boiler, such equipment as the safety valve, electromagnetic valve, water gauge, boiler water circulating pump etc. should be separate from the system.

2.11 Maintenance of Boiler Steel Frame, Platform Handrail and Manhole

2.11.1 Structure of boiler steel frame

The boiler is disposed open to air. It’s structures mainly includes support posts and suspending load beams. The support posts include 6 sysmetric steel frame upright post as the core support, between the main posts, it's connected with cross beam, in order to add the stability of steel beam.

2.11.2 Maintenance of Boiler Steel Frame, Platform Handrail and Manhole

Maintenance item Workmanship and precautions

Quality standard

Inspection of steel beam at top of furnace

1. Measure with thin wire the deflection of main suspension beam and other secondary beam.

2. Check the surface erosion of beams.

3. Check the levelness of transient beams and suspension screws and nuts.

1. The deflection of main beams should be less than 1/850.

2. The surface of beam has no erosion, the surface of metal has no skin, the painting is well.

3. The bending deformation on the length of transint beam less than 5 mm, the suspension screws is even loaded and nuts have no looseness.

II Rigid beam inspection

1. Inspect the straightness of rigid beam.

2. Check the surface erosion of rigid beam.

3. Check the weld between rigid beam and connection

1. The rigid beam has no serious deformation.

2. The surfaces of rigid beams have no erosion, the metal has no skin.

3. The connection plate between rigid beam and water wall has no cracks.

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plate of water wall.

4. Check the gap between horizontal beam and vertical rigid beam.

5. Check the corner connection plate between horizontal beam and vertical rigid beam.

4. The gaps between horizontal beam and vertical rigid beam are even, the expansion is free.

5. The corner connection plate between horizontal beam and vertical rigid beam has no deformation and is flex without clog.

III Inspection of hangers of header at heating area

1. Check the fillet welds of lifting eyes of hangers of headers at heating areas. Clear the rust on the surfaces of fillet weld before the check.

2. Check the straightness and erosion of handger. Swing the hanger with hand to check the degree of tightness.

3. Check the suspension screws and base plates of hangers.

1. The fillet welds of lifting eye have no cracks.

2. The hangers has no deformation, erosion and is evenly loaded.

3. The suspension nuts of hangers have no looseness, the base plates have no deformation.

IV Platform handrail

Check whether the paddle of handrail and connection welds with platform or connection screws is loose.

1. The hollow grid plate of platform is flat, without loose welding or false welding.

2. The handrails have no deformation, erosion, they are securely welded, without false welding or loose welding.

3. The connection welds of handrail to the platform has no cracks, the pedal plates have no deformation or looseness. If it’s connection screw, no looseness should exist.

V Manhole

1. Check the completeness of insulation to door cover of manhole and fire watching hole.

2. Lubricate and loose the

1. The manhole, fire watching door is tightly sealed after close.

2. The inside insulation lining of door cover is complete, without cracks and

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hinges of manhole and fire watching door until the flexibility.

3. When replacing the manhole and fire watching door, lubricate the fixing screws and nuts of frame for a while, and remove the nuts. After the mounting of frame, it must be flat and tight.

falling off.

3. The switch of manhole and fire watching door is flex, without clog.

2.12 Special Tools and Spare Parts and Material for Maintenance of Boiler Proper

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3 Valve, Water Level gauge, Pipe and Accessories

3.1 Maintenance of Safety Valve

3.1.1 Structure of Safety Valve

8 spring safety valves made by Crosby Company are equipped the boiler. The arrangement positions are:

Drum 3

Superheater outlet pipe 1

Reheater inlet pipe 2

Reheater outlet pipe 2

A draining solenoid valve is installed on the superheater outlet pipe with a brand of VTI and supplied by Crosby Company.

The setting pressure and discharge capacity of safety valve is in accordance with ASME. The maximum evaporation of boiler is 995t/h and total discharge capacity of drum safety valve is 881.796t/h, accounting to 88.62% of the maximum evaporation. Discharge capacity of superheater safety valve is 153.86t/h, 15.46% of the maximum evaporation. The total discharge capacity of drum and superheater safety valve is 1035.656t/h, 104.09% of the maximum evaporation.

The maximum flow of reheat steam is 848.6t/h. the total discharge capacity of reheater inlet safety valves is 512.94t/h, 60.45% of the maximum flow of reheat steam. Total discharge capacity of reheater outlet safety valves is 379.157t/h, 44.68% of the maximum flow of reheat steam. the total discharge capacity of reheater inlet and outlet safety valves is 892.097t/h,为105.13% of the maximum flow of reheat steam.

The discharge capacity of power-operated discharge valve is 166t/h, 16.68% of total evaporation of boiler, which is not included in the discharge capacity of safety valve.

Safety valve is the major protection equipment for boiler equipment. When boiler pressure exceeds allowable value, the inlet pressure of valve will increase so that the force applied on the valve disc will be equal to or greater than the spring force. Then the disc will leave the close position and the openness chock block will block the cover plate. The valve is to be at full open position. Steam enters steam chamber H via two blow holes on the top of disc ring. Meanwhile, stem overlapping ring will go up to the fixed position above the levitation gasket. The clearance between levitation gasket and stem will increase because of enlarged diameter of overlapping ring. Therefore steam in chamber H can enter steam chamber Q via the gap between levitation gasket and overlapping ring and vent to the air through orifice and discharge pipe. When boiler pressure drops to a safe value, the force applied by upper adjusting ring is lower than that of spring at the discharge outlet of safety valve. Then the valve disc closes downwards and overlapping ring will move downwards along with valve stem into the levitation gasket effectively reducing the steam discharge of the steam chamber H. An instantaneous combined

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press force in the chamber H will push along with the flow direction of orifice and direction of spring force ensuring the valve disc accurately close. The lower adjusting ring controls the buffer of disc closing. Safety valve can effectively and accurately return to the close position without damaging the valve disc and sealing surface.

Summary table of setting pressure and discharge capacity of safety valve

Setting pressure Design temperature

Serial No.

Valve type

Size

(inch) jump up

MPa

reseat

MPa

Differential return pressure

%

Steam discharge

t/h ℃

Drum safety valve

1 HE-96W 3 M2 6

20.50 19.89 3 291.697 369

2 HE-96W 3 M2 6

20.60 19.78 4 293.924 369

3 HE-96W 3 M2 6

20.70 19.67 5 296.175 369

Superheater outlet safety valve

4 HCI-98W 3 L2

6 18.70 18.14 3 153.860 557

Reheater inlet safety valve

5 HCI-46W 6 RR10 4.50 4.37 3 253.574 313

6

HCI-46W 6 RR10 4.60 4.46 3 259.366 313

Reheater outlet safety valve:

7 HCI-48W 6 RR10 4.10 3.98 3 187.347 554

8 HCI-48W 6 RR10 4.20 4.07 3 191.810 554

Draining solenoid valve

9 E0L121N7BWRA5P1 2.5″×4″ 18.50 18.13 2 166 557

3.1.2 Maintenance of safety valve

Maintenance item


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Maintenance item


(I) Maintenance Preparation

1. Open vent valves of drum and other heating equipment ensuring the pressure in drum or other heating equipment is equal to ambient before maintenance of safety valve.

2. Clean rusted matters in water-delivering pad of steam discharge pipe.

(II) Disassembly 1. Remove operating lever pin and operating lever on the top of valve, and loose valve cap set screw of lift-gearing device, and then take off valve cap and lower down operating lever assembly.

2. Remove fixing pin of reset nut and turn out reset nut.

3. Turn out gland nut from valve stem, and clean dirt on the surface of gland screw with blade cloth ; measure and record the distance A between end surface of gland screw and top of valve stem, refer to Fig 3-3. Loose locking screw of the gland nut, and loose gland nut by special wrench until it separate from upper spring washer.

4. Turn out yoke bar nut and take off yoke support.

Note: evenly turn out yoke bar nut to prevent yoke bar and valve stem from bending. Take out supporting assembly and top spring gasket.

5. Mark original position at spring top, and take out spring bottom gasket at spring bottom from valve stem. Note: if spring bottom is stuck to gasket; separate them before removal of ring.

6. Mark on the notch of valve stem pin hole located on the overlapping lantern ring, and then rotate overlapping lantern ring counterclockwise until the lowest one of four

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Maintenance item


lines is on the same line of upper levitation gasket. Count and record notches passing by the valve stem pin hole. See Fig 3-4.

Make positioning marks on the cover plate and vent hole, and remove stud nuts of cover plate and take off cover plate.

7. Lift valve stem together with valve clack, junk ring assembly out of valve body, and horizontally put them in a clean area.

Note: during lifting and putting valve stem together with valve clack, junk ring assembly, do not crash them and ensure sealing surface of valve clack undamaged.

8. Vertically erect valve stem and secure it. Then lift junk ring and rotate it counterclockwise to engage it with downwards thread. Loose junk ring until take off valve clack. Take out junk ring from valve stem. Refer to Fig 3-50.

9. Remove pin of upper adjusting ring from valve seat; vertically lift guidance; and take out pin of upper adjusting ring and guidance assembly; make an axial mark on the guidance and pin of upper adjusting ring with marker,. Refer to Fig 3-6; turn off pin of upper adjusting ring from guidance. Note: do not change the setting of pin of upper adjusting ring.

10. Loose the pin of lower adjusting ring until the notches of pin and ring separate slightly. Place a plate on the top of sleeve seat, and mark on the pin notch of the lower adjusting ring, taking the pin as reference, rotate the lower adjusting ring counterclockwise until the ring contact with the plate. Count and record the number of notches passing by the pin of lower adjusting ring; turn off the lower adjusting ring from valve seat sleeve and take it out from

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Maintenance item


the valve body, see Fig 3-7.

Note: do not rotate the lower adjusting ring during turning off the pin.

11. After removal of parts inside valve body, install cover plate and stick strip seal on the valve body to prevent dirt from entering. Check the amount of parts after removal, and put them into oil for washing. Then wipe up them with clean blade cloth and put them at specified location.

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Maintenance item


(III) Check and grinding of valve clack, valve clack junk ring and guidance

1. Wipe up the valve clack, with a clean and soft blade cloth; check its sealing surface, internal thread and supporting surface.

2. Grind the valve clack with special circle-shape grinding plate. Before usage, coat the surface by grinding agent with #1000 mill grains, and then grind on the grinding plate of the standard plane until it is plain. Grinding can be carried out as per Fig 3-8.

3. Wipe up the ground circle shape grinding plate with a clean and soft blade cloth and coat the sealing surface of valve clack with a thin layer of #400 grinding agent. Put the circle shape plate on the sealing surface, and manually push it to distribute the weight of the plate evenly to the sealing surface. Grind the plate by moving it at all direction evenly until defects such as scratches and crackle are eliminates and a mirror face is formed.

Note: during grinding, prevent the internal and external edges from running put of the sealing surface of valve clack to avoid damage to sealing surface. In addition, the cone part should not be crashed.

4. Wipe up the sealing surface of valve clack with a clean and soft blade cloth, and measure the project value(C-B) of the sealing surface, see Fig 3-9. Replace the valve clack if the measured value is less than tabulated value.

5. Check the end section of valve clack junk ring and two holes on the valve clack junk ring. Grind the outer surface with metallographical sand paper until it becomes glossy.

6. Check the internal surface and ellipticity of the guidance and check the outer thread of the guidance. 7. Measure and record the clearance between guidance and valve clack junk ring.

1. No corrosion, crackle, or nick is on the valve clack; sealing surface is glossy without notch, stain; the thread is not damaged.

2. No corrosion on end section of valve clack junk ring; steam hole is free-flowing; no ellipticity of the outer diameter of the junk ring; no serious abrasion on the outer surface, which is plain and smooth.

3. No ellipticity of the inner surface of the guidance; no serious abrasion, and no damage on thread.

4. Requirements on the clearance between guidance and valve clack junk ring are shown in tables.

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Maintenance item


(IV) Check of overlapping lantern ring and cover plate

1. Check outer surface and thread of lantern ring.

2. Grind the outer surface of the lantern ring with crocus paper.

3. Check surface of cover plate and steam exhaust hole.

4. Check inner surface of levitation gasket and guard ring of the gasket.

1. No defect or flaw on the outer diameter of the lantern ring; surface is glossy; thread is not damaged.

2. Cover plate is plain without any deformation.

3. No seizing, bending or deformation of levitation ring is in the cover; its inner surface is smooth without any Pitting or abrasion.

4. No damage or serious abrasion to the guarding ring of the gasket.

(V) Maintenance of the valve seat sleeve

1. Wipe up the sealing surface of valve seat with a clean and soft blade cloth, and check the sealing surface.

2. The grinding of valve seat sleeve is the same as valve clack. However, before grinding, grind the taper angles on the edges to eliminate small metal particles and burrs.

3. Measure the size shown in Fig 3-1; replace the valve or resurfacing weld the sealing surface of the valve seat sleeve if the measured value is over limit.

1. Surface of valve seat sleeve is glossy without any crackle or damage.

2. No crackle or scratch on the sealing surface of the valve seat sleeve.

3. The thickness of the sealing surface valve seat sleeve is shown in tables.

(VI) Check of valve stem

1. Place and secure the valve stem on a lathe; put the contact head of a dial test indicator on the surface of the valve stem, and rotate valve stem to observe the variation of the dial test indicator.

Note: protect the valve stem with a soft cushion when secure it and the securing position should not on the thread.

2. Wipe up the surface of valve stem thread

1. Bending value of valve stem should be less than 0.177 mm.

2. No damage or burr is on the valve stem thread.

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Maintenance item


with a clean blade cloth and check thread.

(VII) Check and grinding of spring and spring gasket

1. Visually inspect the spring.

2. Wipe up the spring gasket with a clean blade cloth and check supporting surface.

3. #320 particle grinding agent should be used for primary grinding of spring bottom gasket and valve stem grinding and then use #1000 particle grinding agent for accurate grinding until it is qualified. Wipe up spring bottom gasket and valve stem with a clean and soft blade cloth after grinding.

1. No crackle or corrosion on spring.

2. Spring gasket is plain without deformation or crackle.

3. Width of back supporting strip of the spring bottom gasket and valve stem is even and in the range of 3.2~4.8mm.

(VIII) Recovery 1. Clean debris in valve body. Note: wrap up valve seat sleeve with cloth when cleaning to prevent sealing surface from damage and debris from entering valve inlet tube seat.

2. Vertically erect valve stem on the soft cushion with the ball end up.

Apply lubricant on the ball surface and thread of the valve stem, turn the turndown ratio choke block and valve clack into valve stem. Slowly slip the valve clack block on valve stem and seat it on the valve clack.

Note: do not damage valve clack ring. Then carefully turn the valve clack onto valve stem and check swaying of valve clack. If valve clack can not sway, adjust the height of the valve clack ring until valve clack can freely sway. After check valve clack swaying, take off valve clack and junk ring, secure the ring with stainless steel pin and then install valve clack junk ring onto valve stem.

3. Install yoke bar into valve body, and secure it with nut.

Note: the position yoke bar turned in valve body should be in accordance with the mark

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Maintenance item


made during disassembly. Coat the thread with supramoly.

4. Turn the pin of lower adjusting ring into valve body, and then turn the lower adjusting ring into valve seat sleeve making the upper end surface lower than that of valve seat sleeve. Place a plate on the top of valve seat sleeve; turn the lower adjusting ring to contact it. Taking this as reference, rotate the lower adjusting ring into original position based on recorded data during disassembling and secure it with pin. If the original position needs to be adjusted, 4.13MPa should be used for setting pressure drop caused by each notch decreasing.

Note: adjusting ring should be able to turn slightly after installation; otherwise, the end of positioning pin needs to be ground as required. Coat the adjusting ring and thread of the pin with supramoly.

5. Turn the pin of upper adjusting ring onto guidance until the marks overlap, where the pin of upper adjusting ring is previously located. Measure their lengths and compare them with recorded data to ensure the upper adjusting ring is located on the original position on guidance. See Fig 3-11.

Note: cost the thread of guidance with supramoly.

After adjustment, secure pin of upper adjusting ring with pin immediately. Note: guidance supporting surface of valve seat should be coated with supramoly.

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Maintenance item


6. Put the guidance and upper adjusting block assembly into valve body; measure the end surface of valve seat sleeve with depth indicator, and compare it with the recorded value. The difference is the distance that the pin of upper adjusting ring needs to be lowered. It can be carried out by adjust the number of notches.

Serial No. of orifice Ring vertical distance during adjusting each notches (mm)

3 0.038

4 0.038

5 0.038

R 0.038

After adjustment, secure pin of upper adjusting ring with pin immediately. Note: guidance supporting surface of valve seat should be coated with supramoly.

7. Wipe up the surface of valve clack seat with a clean and soft blade cloth and carefully install the valve stem into guidance. Check internal valve body, install and secure the cover plate onto the valve body after verification as per marked made during disassembling.

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Maintenance item


If the turndown ratio is different from tabulated value, remove yoke support and cover plate and take off valve stem assembly and valve clack block. Install a stainless steel pin on the turndown ratio choke block and install the block into guidance. Recheck internal valve body and recover and secure cover plate with nut. If the turndown ratio is different from the tabulated value, take off valve stem, and adjust the notch of turndown ratio choke block. Each movement of one notch, it will increase or decrease 0.0254mm.

5. Slip the overlapping lantern ring onto valve stem and turn it clockwise until the lowest line on the lantern ring is at the same level as levitation gasket. Turn it to the original position based on recorded notch number and taking pin hole as reference. Install stainless steel pin through the notch of overlapping lantern ring.

Note: coat thread of valve stem with supramoly before install overlapping lantern ring onto valve stem.

6. Install spring bottom gasket, spring and top gasket of spring onto valve stem in sequence. Put the locking nut onto the thrust screw, and turn the thrust screw into yoke support until screw end comes out of bottom of yoke support. Put the yoke support onto valve stem and yoke bar. Align the locking nut with spring gasket during installation. Turn the yoke bar nut into yoke bar and secure it with torque wrench. Torque for different pressures is shown in tables.

Note: coat the spring bottom gasket and thread with supramoly

7. Turn the thrust screw into original position and tighten the locking nut.

Note: coat thread of yoke bar nut, thrust screw locking screw with supramoly. Coat top surface of yoke bar screw with supramoly.

8. Put the reset nut onto valve stem and turn it clockwise until it is fully engaged with valve

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Maintenance item


(IX) Hydraulic pressure setting of safety valve

1. Remove cap and lever assemble of safety valve, loose locking nut and install setting device for primary setting.

2. Stabilize steam pressure at 70%~80% of working pressure as setting pressure.

Note: the fluctuation of setting pressure shall be less than 1%, the indication of local steam pressure prevails.

3. Startup hydraulic pressure pump, increase the pressure until “Chichi” sound comes from safety valve; record the pressure reading. Calculate the setting pressure of safety valve according to the data in table. (Refer to Table3-1 and Table 3-2).

4. Adjust bolt as per pressure data of the primary action and record the adjustment. To increase jumping pressure, turn the thrust bolt clockwise.

(X) Site thermal calibration (determine calibration quantity as required)

1. Special personnel should be appointed for instructing calibration of safety valve.

2. When boiler pressure reaches 80% of working pressure, block safety valves not required for setting, and recover them after calibration.

3. If safety valve does not act when the pressure exceeds setting value of safety valve 0.5MPa, relief the pressure to below 80% of opening value and adjust thrust screw.

Note: turning clockwise will increase opening value, and turning counterclockwise will decrease the opening value .Tighten locking nut after each adjustment.

4. Perform calibration of safety valve after adjust the adjusting screw properly. 5. After calibration of safety valve, record the jumping up time and reseating pressure.

1. Safety valve pops normally.

2. Difference between popping pressure and the setting value is lower than 1%.

3. No leakage occurs after safety valve reseating.

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3.2 Maintenance of Solenoid Relief Valve

3.2.1 Maintenance of Solenoid Relief Valve


(I) Maintenance preparation

1. Close the isolating valve below master valve and turn off the power of controller.

2. Push operating lever down to bottom to relieve the remaining pressure in pilot valve and master valve.

(II) Master valve disassembly

1. Remove flange bolt and nut of steam discharge pipe and take off steam discharge pipe. Remove flange nut of valve seat and take off lantern ring (outlet flange). Slightly click and loose C sealing ring on the contacting surface of valve seat flange, and take it off.

Note: do not damage the sealing surface during removal C sealing ring ; bolt and should be put into oil by pairs after removal.

2. Knock and loose the valve clack and guidance with copper bar. Turn a screw stem into the hole on the top of valve clack to take out valve clack and then take out spring in guidance.Note: do not crash the valve clack and guidance with valve seat or valve seat thread when taking them out.

3. Knock and loose the retaining ring with copper bar, and take it out.

(III) Check and grinding of master valve parts

1. Wipe up the sealing surface S with clean blade cloth and diesel before check the sealing surface of master valve seat check.

2. When primarily check the sealing surface, perform grinding if any

1. Sealing surface of valve seat is glossy and plain without damage or corrosive pitting or dent.

2. No dirt in valve seat or thread.

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obvious defect or corrosive pitting is found. Firstly coat coarse particle grinding agent on plate to grind sealing surface until defects are eliminated, and then apply fine particle grinding agent for accurate grinding until sealing surface is glossy. At last, apply polishing grinding agent on plate to polish the sealing surface. See Fig 3-14. Note:(1) before grinding, use crocus paper to round chamfer of grinding surface and other valve seat surfaces to remove metal particles on sharp angles. (2) After every grinding, wipe up sealing surface with clean blade cloth. (3) Grinding should be evenly performed with the same direction.

3. If no defect is found on the sealing surface at the primary check, coat medium particle grinding agent on a special plate and grind the sealing surface until small pots are eliminated. Then wipe up it with clean blade cloth and recheck sealing surface. If any crackle or corrosive pitting is found, perform grinding as per procedure 2.

4. Clean the inner wall and thread of the valve seat with diesel and blade cloth.

5. Put sleeve, guidance, valve clack, and spring and check washer into oil to wash them, and wipe up them with clean blade cloth.

6. Check and grind the bottoms of sleeve sealing surface C and C sealing ring. See Fig3-15 and Fig 3-16. The method of check and grinding is the same as Procedure 2.

3. No dirt inside or outside of sleeve; thread is intact without burrs; sealing surface is glossy and plain without damage or corrosive pitting; no crackle on sealing surface of valve clack seat.

4. Sealing surface of valve clack is glossy and plain without damage or corrosion; well contact with valve seat with continuous and even contacting surface.

5. Surface of lock washer is glossy and plain without dirt and spring is not loose.

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If the depth of the notch exceeds 6mm, grind sealing surface to recover it to the original value.

7. Check sealing surface of sleeve and valve clack. The method is the same as that of procedure 2 and 3. If the sealing surface is found seriously damaged during the primary check, machining is needed to recover it to original size. Note: sealing surface is required to be ground after machining. The method is the same as procedure 2. During grinding, the centerline of plate should be in accordance with those of sleeve and guidance.

8. Wipe and check the sealing surface of valve clack. If any crackle or corrosive pitting is found on the sealing surface, continue to process valve clack. After machining, grind the valve clack to fit sleeve. Put valve clack on sleeve with matching their centerline. Mark a connecting line on the sleeve, which is the upper edge of connecting surface between valve clack and sleeve. Carefully coat a little grinding agent below the connecting line, and place valve clack seat of sleeve again. Perform grinding after alignment until the width of contacting surface is 1/3 of the valve clack seat of sleeve. See Fig 3-17. The area in the sealing surface of valve clack and sleeve. Coat grinding agent to grind the sealing surface.

9. Check the surface of guidance, spring, check washer, and check the relaxation of spring.

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(IV) Assembling of master valve

1. Put the spring and check washer on valve seat.

2. Put the guidance into valve seat and securely seat on the supporting plate.

3. Connect the valve clack with installation screw stem, and carefully put valve clack into the guidance by aligning with the spring.

4. Coat the thread of sleeve with supramoly, and fill Vaseline into the C sealing groove. Put the C sealing ring into it and turn it into master valve until the sealing ring contact with valve seat.

5. Coat the screw with supramoly, turn it into the valve seat and tighten it. Recover the lantern ring (outlet flange) and tighten it with nuts.

1. Guidance is well located and connected with supporting plated without swaying.

2. Spring is well located without swaying or inclination.

3. Valve clack spring is well contacted.

4. Sleeve is well contacted with valve seat, and C sealing ring is well located.

(V) Pilot valve disassembling

1. Remove stud bolt of the frame gland and take off frame gland. And remove frame together with solenoid coil assembly from the controller.

2. When removing parts in pilot valve, stick valve clack to valve seat, and press it with spring cap. Then remove the pin of spring cap and spring.

3. Take out pilot valve stem and pilot valve clack from the pilot valve seat. Note: do not crash valve seat.

4. Slightly kick valve clack with small hammer to pull valve stem out of pilot valve clack. Note: valve stem and valve clack should be carefully laid.

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(VI) Check and grinding of pilot valve parts

1. Clean valve seat cover with a clean blade cloth and diesel, grinding method of pilot valve seat is the same as that of master valve sleeve. See Fig 3-18 and 3-19.

2. Put pilot valve clack, valve stem spring cap and pin of spring cap into oil for washing and wipe them with a clean blade cloth.

3. Put the valve clack on a special grinding tool to grind the sealing surface. If any defect such as abrasion, crackle or corrosion is found on the sealing surface, machining is needed. Grind it after machining. Building-in of valve clack and pilot valve seat cover is the same as that of master valve clack and valve seat.

4. Check the surface and bending ratio of pilot valve stem.

1. No dirt is in the pilot valve seat and the sealing surface in pilot valve seat sleeve is plain and glossy without crackle or corrosion.

2. Pilot valve clack is plain and glossy without crackle, abrasion or corrosion. It is well contacted with sealing surface of pilot valve seat sleeve. Contacting surface is continuous and width is uniform.

3. Surface of pilot valve stem is glossy and flat with a bending value <0.10 mm.

4. Spring of pilot valve stem is not relaxed.

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(VII) Assembling of pilot valve

1. Wipe valve stem and insert it into valve clack. And then insert the well connected assembly into pilot valve seat sleeve. Then put spring and spring cap onto pilot valve stem. Install pin of spring cap after tightly press spring.

2. Clean pilot valve seat and valve seat sleeve with a clean blade cloth. Replace packing seal ring on valve seat sleeve, and then carefully put sleeve into valve seat. Note: do not crash valve stem valve clack assembly with valve seat sleeve during assembling.

3. Install solenoid coil support and tighten it with nut, tightening of nut should be carried out by diagonal sequence. Turn 1/4 circle every time until support fully contact with valve body. Note: before turn in bolt and nut, coat thread with supramoly.

1. No relaxation of the connection between valve stem and valve clack.

2. Sleeve is well secured in valve seat.

3. Solenoid coil support well contacts with valve body, and clamp nuts of support is evenly tightened.

3.3 Maintenance of water level gauge

Item Workmanship and precautions Quality standard

(I) Check preparation

1. After receipt of maintenance permit, check the air valve and local pressure gauge to make sure the pressure inside drum is equal to ambient pressure.

2. Open the drain valve water level gauge to drain the water in water level gauge and piping.

3. Cut off lighting power supply of water level gauge and remove cover.

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(II) Disassembly of water level gauge

1. Loose the gland nut of the water level gauge with wrench and take it out. Knock the gland bush with the wooden hand handle of hammer or other tools to loose it and take it off.

2. Orderly take out packing seal, mica lamination, protective pad, plain glass and buffer cushion in gland bush.

3. Coat the connecting bolt of gland bush and water level gauge with rust loosing agent and turn the bolt out with wrench.

Note: bolt and should be put into oil by pairs after removal.

(III) Check and clean of water level gauge parts

1. Clean the gland bush and sealing surface with blade cloth and diesel, remove relict of graphite adhering to sealing surface. Clean the sealing surface with blade cloth and check sealing surface. If any defect such as corrosive pitting, groove or abrasion is found on sealing surface, grind the sealing surface with special plate and abrasive paper. Machining is needed for serious defects.

2. Put the gland bush on a platform or plate and measure the bending ratio of gland bush.

Note: sealing surface of gland bush should be towards to platform or plate during measurement.

3. Remove dirt on bolt and nut. Check bending ratio of every bolt. Try turning nut to check the thread of bolt and nut.

Note: nut should be turned through entire bolt thread. They should be stored by pair

4. Check mica lamination and plain glass.

1. The sealing surface between the body of water level gauge and gland bush is flat without corrosive pitting, groove, or abrasion. The surface coarseness of the sealing surface after grinding should reach Ra1.60μm.

2. Bending value of gland bush is less than 0.15mm.

3. Bending value of the bolt is less than l mm. No defect on or damage to the thread of bolt and nut.

4. Mica lamination is flat and transparent with uniform thickness and without stain or crease.

5. The plain glass is transparent without notch and with uniform thickness.

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(IV) Assembling of water level gauge

1. Purge communicating pipe of water side and steam side of water level gauge with compressed air, and remove dirt inside pipes.

2. Turn bolt into the body of water level gauge.

Note: the end with short thread of the bolt should be turned into the body of water level gauge with supramoly coated on the thread.

3. Orderly install the cushion gasket of plain glass, protective cover of the upper and lower ends of plain glass, plain glass, mica lamination and high strength graphite packing seal into the gland bush of the water level gauge. Then connect the gland bush and water level gauge with nuts as per the sequence shown in Fig 3-21.

Note: (1) clean the sealing surface before assemble the body of water level gauge and the gland bush. Washers should be used for nut connection. (2) tighten nuts respectively four times with torques as 90N·m,120N·m, 150N·m and 180N·m.

1. The communicating pipe of water side and steam side of water level gauge is smooth and clean.

2. High strength graphite packing seal is plain without impress or crease, and the width and thickness are uniform.

3. Tightening torque on gland nuts is uniform.

(V) Disassembling of stop valves on steam side and water side

1. Fully open the valve and remove gland nut of handwheel to remove the handwheel.

2. Loose the gland nut of the gland bush of gland box to separate the gland nut from gland bush. Knock the gland bush until it is loose and pushed out of the gland box.

3. Loose and take off the stud bolt of valve cap, and knock the valve support downwards to take out the collar of valve cap.

4. Turn the valve stem towards closing direction with wrench until the valve stem together with valve disc separate from the valve body.

5. Coat rust loosing agent on the connecting surface between valve cap and valve body. Knock the valve cap with copper bar to make it

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turn counterclockwise until it separate from valve body. Secure the valve cap and coat rust loosing agent on the contacting surface of valve cap and valve cap nut. Then loose the valve cap and turn it out.

(VI) Check and cleaning of valve parts

1.Wash the inside of valve body, surface of gland box and sealing surface of valve seat with a blade cloth and diesel, and check inside of valve body and the sealing surface of the valve seat.

2. Clean the inner and outer thread of the valve cap with a blade cloth and diesel and check the threads.

3. Clean the valve disc with blade cloth and check its sealing surface. Any stain or crackle should be eliminated by lathe.

4. Grind the sealing surface of valve seat with special grinding tools. There are three grinding levels: coarseness, fineness and precision. #0--2 abrasive paper is used for coarseness grinding, #0-00 abrasive paper is used for fineness grinding and #000 abrasive paper with oil on surface is used for precision grinding.

5. Grind the surface of valve stem with crocus paper coated with oil. Clean with blade cloth and check the thread and the arch part of valve stem. Put the valve stem on a lathe and check the bending ratio of valve stem.

1. No corrosion on the internal wall of the valve body and the surface of gland box is glossy and plain without corrosion.

2. No corrosive pitting or scratching on sealing surface of the valve seat.

3. Inner and outer threads of the valve body and valve cap are free of burrs or deficiency.

4. On burr or abrasion on the valve stem thread with a bending value less than 0.15mm. The top arch of the valve stem is intact without abrasion.

5. No crackle of notch on the sealing surface of the valve disc.

(VII) Assembling of valves

1. Grind the sealing surface of the valve seat by special grinding tool with #200 grinding sand coated on the grinding head. Then coat the sealing surface of the valve disc with red lead powder and assemble valve disc and valve seat.

2. Put the valve disc and valve stem into valve body after assembling.

1. The sealing surface between valve seat and valve disc is continuous and the width of sealing surface is evenly around 2mm.

2. The clearance between top of valve stem and valve

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3. Put the gland bush of the gland box on the valve stem and fill gland packing into gland box.

Note: the opening of packing should be stagger with 90º.

4. Turn the valve cap into valve body until secure the valve cap with stud bolts. Install collar into valve cap. Insert gland bush bolt into gland bush and tighten it with nut.

Note: the thread of valve body and gland bush bolt should be coated with supramoly.

5. Turn valve stem nut into valve cap and tighten it.

Note: nut thread should be coated with supramoly.

6. Recover valve handwheel and tighten it with nut.

7. Rotate the handwheel to make valve stem operate freely.

disc is 0.3~1mm.

3. The operation of opening and closing valve is freely without seizing.

(VIII) Zero calibration and check of water level gauge

1. Find out the horizontal center points from the circumferential direction of the two sides of drum cylinder.

2. Connect the horizontal center points of the two sides with the water level gauge by a hose filled with water.

3. Taking the position of horizontal center point as reference, the zero level of the drum water level gauge is 328.6mm below.

4. Taking the position of horizontal center point as reference, measure the inclined value and inclining direction of drum. Based on the inclining direction, calculated out the position line of zero level and mark it.

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3.4 Maintenance of Desuperheating Control Valve

Maintenance item


(I)Disassembly 1. Remove signal feeding back mechanism on the actuator and the connecting block of valve stem and valve actuator.

2. Slightly knock the retaining nut of actuator and valve yoke support with hammer and flat chisel until the nut is fully loose and take it off.

3. Lift the actuator away from valve and well store it. Take out indicating dial of turndown ratio on the valve stem and its retaining nut.

4. Remove gland cover nut and take out junk ring of gland cover and packing.

5. Counterclockwise knock the flange nut of the valve cap with hammer and wrench until it becomes loose. Remove valve cap from valve body.

Note: do not crash the valve stem when separating valve cap.

6. Take out valve stem, valve disc assembly and valve seat sleeve. Then loose the junk ring of the valve seat by wrench. Take out junk ring of valve seat and valve seat ring.

(II) Cleaning valve parts

1. Clean gland box of valve cap with diesel and blade cloth. Then grind the internal wall to smooth.

2. Clean valve seat ring and junk ring of valve seat with diesel and blade cloth. Then grind the sealing surface of valve seat and valve seat ring.

3. Clean the surface of valve disc with blade cloth and check its sealing surface. Assemble the valve disc and valve clack.

4. Grind the surface of valve seat sleeve with crocus paper, and check and measure its ellipticity.

5. Clean the valve stem with diesel, and check its thread and bending ratio.

6. Clean the internal valve body with blade cloth and

1. Internal wall of the gland box is Glossy without notch, corrosion, or air hole.

2. The sealing surface between valve seat and valve seat ring is plain without abrasion, crackle, or corrosive pitting.

3. The internal and external surface of

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check its internal wall and grind the flange of valve body with crocus paper.

7. Clean the thread of valve cap yoke support with diesel and blade cloth and check its thread. Grind the flange surface of valve cap yoke support with abrasive paper.

valve disc is clean and glossy without deformation, abrasion, crackle or corrosive pitting.

4. Surface of the valve seat sleeve is glossy without abrasion, crackle, or corrosive pitting. With an ellipticity less than 0.10mm.

5. Valve stem thread is not damaged with a bending value less than 0.15 mm.

6. No dirt or debris inside valve body; internal wall of valve body is free of corrosion, air hole or crackle.

7. The contacting of valve seat ring and valve disc is continuous with an even width.

8. Flange is ground with metal luster.

(III) Assembling

1. Carefully put the gasket of the valve seat ring into valve seat, and tighten the valve seat junk ring with special tool.

Note: thread of the valve seat junk ring should be coated with supramoly.

2. Put the valve seat sleeve into valve body. Put packing on the valve stem and assemble it with valve disc, then put them into valve seat sleeve to contact with valve seat ring. Rotate the valve stem to ensure

1. Valve disc rotates freely without seizing. Clearance between valve disc and sleeve is 0.10- 0.20 mm.

2. Clearance between gland

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valve disc can operate freely.

3. Put gasket on the valve body flange; recover valve cap and tighten the nuts.

Note: surface of HP gasket and connecting bolt should be coated with supramoly.

4. Install packing assembly into gland box; tighten the packing with junk ring and gland bush, and then tighten bolts.

5. Turn the retaining nut and turndown ratio indicating dial of the actuator into valve stem, and lift actuator to the yoke support of valve cap. Symmetrically put two shim plates with a thickness of 35mm on the yoke support. Adjust thread of valve stem, and recover the connecting block of actuator and valve; secure the turndown ratio indicating dial.

6. Take out two shim plates and recover yoke support nuts.

cover and valve stem is uniform.

3. Threads of valve stem and valve stem sleeve are well engaged with that of connecting block.

3.5 Valves

3.5.1 Maintenance of HP Gate Valve

HP gate valve is used to cut off or put through boiler feed water or desuperheating water. It is a kind of self-sealing gate valve. Main feed water gate valve is double ram type while the feed water bypass gate valve and desuperheating water gate valve are single ram type. The connection and disconnection of flow is achieved by movement of wedge valve clack and sealing of wedge valve seat.

Maintenance item


(I)Disassembling 1. Remove external connecting wires of actuator and remove connecting bolt of valve and actuator; lift the actuator away from valve and carefully store it.

2. Remove the retaining bolt on the top frame of valve cap; turn the valve stem nut counterclockwise to take off valve frame from valve body. Lift the fame and put it at suitable position. Valve stem is ready for disassembling check.

3. Remove gland cover nut and take out gland cover and packing junk ring.

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4. Take out retaining ring at the sealing ring of valve body; press down valve cap with special tool. Knock the valve cap with valve cap hammer to make a clearance between it and six-element ring; take out six-element ring and lift valve cap, valve stem, valve clack out of valve body .

5. Take out upper and lower cleat disassembly of valve clack frame, left and right valve clack. And take care of the universal jack and gasket. Measure and record the total thickness of the gasket.

6. Cover the valve body with special cover plate and stick seal on it.

(II) Cleaning valve parts

1 remove valve cap and self- sealing gland packing; remove scaling and rust on the external wall of the packing retaining ring; grind it with abrasive paper to be glossy.

2. Clean the packing set of valve stem gland box and verfy that internal packing seat retainer is intact, clearance between internal hole and valve stem meets requirements and no seizing exists between outer ring and internal wall of gland box.

3. Grind the sealing surface of valve seat and valve clack.

4. Coat the sealing surface with red lead powder; assemble the valve seat and valve clack. Check the engagement of sealing surface between valve clack and valve disc after grinding.

5. Grind the surfaces of gland cover and six-element ring with abrasive paper to remove rust.

6. Clean the valve stem with diesel and check its thread and bending ratio.

7. Clean the internal valve body with blade cloth and then check its internal wall.

8. The flange surface of valve cap frame should be ground by abrasive paper.

9. Wash the valve stem nut and internal bearing with diesel.

1. Internal wall of gland box is glossy without notch, corrosion, or air hole.

2. Roughness Ra value of the sealing surface between valve seat and valve clack after grinding is 0.4 without abrasion, crackle, or corrosive pitting. The engaging surface between valve seat and valve clack should have a width of 2/3 of total.

3. Welding of valve seat is free of abrasion, crackle, or corrosive pitting.

4. Valve stem thread is not damaged with a bending value less

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than 0.10 mm.


7. Bearing turns freely without seizing.

(III) Assembling

1. Reinstall valve clack to retaining ring of valve stem, and secure it by the upper and lower cleats. Then put in universal jack or spring. Adjust the gasket number depending on the volume ground from valve clack seat.

2. Clean inside of valve body, and put valve stem together with valve clack into the valve body. Check the relative height of valve clack sealing surface to that of valve seat. Adjust the gasket if necessary.

3. Install gland packing at the self-sealing parts of valve cap as required. Press upper packing with retaining ring. Then install six-element ring and seal it with cover plate. Tighten the nut for lifting bolt of valve cap.

Note: connecting bolts should be coated with supramoly.

4. Put the valve stem packing assembly into gland box; tighten the packing with junk ring and gland bush, and then tighten bolts.

5. Recover the frame of valve cap, and turn the upper valve stem nut to set the frame on the valve body. Tighten it with connecting bolts.

6. Lift actuator to the frame of valve cap; manually operate the actuator until it engages with the valve stem nut. Tighten the connecting bolts and manually check the closing and opening operation.

1. Sealing surface of the valve clack should be 3-5 mm higher than seat sealing surface.

2. Clearance between gland cover and valve stem is uniform.

3. Threads of valve stem and valve stem nut are well engaged.

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3.5.2 Maintenance of HP Stop Valve

HP stop valve is used to cut off or put through the working medium in pipes. The body of stop valves used for boiler drainage system and exhaust system, stop valve are streamline type normally to reduce flowing resistance loss. The sealing methods of valve cap include flange type and self-sealing type while the sealing surface is divided into plain type and cone type.

Maintenance item


(I)disassembly 1. Remove set screw and grind the welding points from the conjunction part of valve cap and valve body by an angle direction grinding wheel.

2. Close valve and take out retaining ring.

3. Manually rotate the frame counterclockwise, and take out the valve cap, valve stem, and assembly around frame from valve body.

4. When disassembling valve stem, remove handwheel first and rotate the valve stem clockwise and pull it put at the same time.

5. Clean internal valve body and check sealing surface of valve seat; cover the valve body with special cover.

(II) Cleaning of valve parts

1. Clean valve cap and gland box packing, and remove gland cover, retaining ring and packing seat retainer. Then grind them to be glossy to ensure gland bush can be freely installed into the gland box.

2. Put the sealing surface of valve clack on lathe for polishing, and grind the sealing surface of valve seat with grinding tool.

3. Grind the sealing surface valve seat and valve clack.

4. Wipe the sealing surface with red lead powder, and face up the sealing surface of valve seat and valve clack. Check the engagement of valve clack and valve disc.

5. Clean valve stem with diesel and check its thread and bending ratio.

6. Clean internal valve body with blade cloth and

1. Internal wall of the gland box is glossy free of notch, corrosion or air hole.

2. Roughness Ra value of the sealing surface between valve seat and valve clack after grinding is 0.8 without abrasion, crackle or corrosive pitting. Valve seat and valve clack should have a width of 2/3 of total.

3. Clearance

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checkits internal wall.

7. Check valve stem nut and bearing.

between internal bore of packing seat retainer and valve stem is 0.25-0.35 mm; no seizing exists between the outer bore and internal wall of gland box.

4. Thread of valve stem is not damaged with a bending valueless than 0.10 mm.


(III)Assembling

1. Check no foreign matter in valve body and clean internal valve body.

2. Install valve clack, valve stem, valve cap into valve body.

3. Install valve stem packing into gland box and press packing with gland bush.

4. Install retaining ring and tighten valve cap ring, gland cover bolt.

5. Install handwheel and set valve in close state.

6. Put on the nameplate of valve and clean the site.

1. Clearance between gland covered valve stem is uniform.

2. Thread of the valve stem and valve stem nut are well engaged.

3.6 Blowdown Flash Tank

3.6.1 Technical Specifications of Blowdown Flash Tank

The tank is composed of steam-water separator, throttle ring, and steam-water separating baffle with a horizontal arrangement.

Manufacturer: Jinan Pressure Vessel Factory

Main technical parameters of blowdown flash tank:

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Name Regular blowdown flash tank

Continuous blowdown flash tank

Design pressure (MPa) 0.98 1.040

Design temperature( )℃ 300 364

Working pressure (MPa) 0.0098-0.392 0.912

Working temperature ( )℃ 102-151 181

Working volume (m3) 12 Steam 2.2 / water 0. 8

total volume (m3) 14.8 3

Max. blowdown rate (t/h) 20.6(2% of the rated evaporation)

Normal blowdown rate (t/h) 10.3(1% of the rated evaporation)

Internal diameter of cylinder (mm)

2000 1200

3.6.2 Maintenance of Blowdown Flash Tank

Taking the maintenance of regular blowdown flash tank as example, the maintenance of continuous blowdown flash tank shall be in accordance with:

1) During outage, anti-corrosion provisions should be carried out.

2) Outside of equipment should be checked every year while the inside should be checked every three years. The content check include: check and treatment of appearance, the corrosion and abrasion of parts inside and outside of equipment, thickness of pressure parts.

3) If the maintenance and check may affect the security of equipment, pressure withstanding test should be carried out. Pressure withstanding test on equipment should be performed at least every ten years. (As per the test pressure specified on the name plate)


(I) Check preparation

1. Open the exhaust steam valve and draw-off valve to ensure the pressure inside vessel is equal to the ambient pressure without residual water.

2. Open the manhole to fully cool the vessel with a natural method.

Note: maintenance staff should not enter the vessel until the temperature drops below 40 .℃

Set a temporary manhole with suitable

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maintenance clearance. The lighting and electric tools used in vessel should be in accordance with Clause 272 and 274 specified in [Working Regulation of Power Safety] (part of heating power and the machine section).

(II) Check vessel internal wall and parts

1. Check the scaling of internal wall by chemical supervision staff and take sample of scale.

2. Clean the internal wall and the surface of steam-water separating baffle with compressed air and steel wire.

3. Check the circular seam and longitudinal seam on the internal wall of vessel. Repair the welding if scallop or crackle is oversize.

4. Check the weld seams between steam-water separating baffle and cylinder and those among themselves.

5. If steam-water separating baffle falls down because of impulse, check the throttle ring and steam-water separator. Replace the seriously deformed steam-water separating baffle or throttle ring.

6. Grind the fillet weld on the tube support with grinder and then check the crackle on the fillet weld by means of staining method.

1 internal wall of cylinder, surface of steam-water separating baffle is plain without dirt. Steam-water separating baffle is well welded with the cylinder without crackle or sealingoff.

2. The size of scallops on the internal wall of cylinder should be less than 5mm.

3. The throttle ring and steam-water separator are free of deformation or falling down.

4. Weld seam of tube support on the cylinder is free of crackle.

(III) Close the manhole

1. Clean the residual matters on the manhole contacting surface with perching knife. And then grind it with abrasive paper. If serious notch or abrasion is found, repair the weld of defects and grind the surface to be glossy.

2. Clean and check the inside of the cylinder before close the manhole.

Note: coat supramoly on the both sides of the HP sealing packing gasket and bolts.

3. Close the manhole and tighten it with nuts. Nuts should be tightened as per diagonal sequence. Retighten them in hot state.

1. No any matter is left inside the vessel.

2. The contacting surface of the manhole is plain, and glossy without notch or abrasion.

3. The contacting surface is well touched after manhole closing and the bolts are evenly forced.

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4. Contacing surface of manhole is free of leakage.

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4 Coal pulverizing system

4.1 Steel Ball Coal Mill

4.1.1 Steel Ball Coal Mill Technical Specifications

BBI4796 type steel ball coal mill is manufactured by Shanghai Heavy Machinery Plant Company Limited. It is equipped with jacking oil system and slow speed drive device. It is composed of front and rear hoppers, rotating part, main bearing, drive component, reducer, gear and pinion, lube oil system and motor. Rotating part is a cylinder made by steel plate and its inner wall is furnished with wave-shaped steel tiles. The material is hard low alloy liner plate. There is a layer of asbestos rubber pad between cylinder and liner plate, which is used to prevent heat inside cylinder from losing and to buffer the impulsion from steel balls. Hard wearing steel ball are equipped inside of cylinder. The rotating speed of cylinder is 13.18 r/min. There is an end cap for each end of cylinder. Inner cap is furnished with sector liner plate and asbestos rubber pad. Outer cap is connected with hollow shaft. The neck of hollow shaft is located on the bearing of main shaft. Each end of hollow shaft is connected with a 45 degree elbow. One is for inlet of raw coal and drying medium and the other is used as outlet of air-pulverized coal mixture.

When cylinder rotates, steel balls are taken to a certain height by the wave-shaped steel tiles and fall down to strike raw coal. Raw coal is ground to pulverized coal under the combine action of steel balls, steel tiles. Drying medium is used to dry and carry pulverized coal. Under the negative pressure suction of pulverization system, finished pulverized coal is transported along with drying medium to furnace for combustion.

(II) structure is shown in the figure below:

Diagram of BBI4796 type coal mill

1.Inlet hopper 2. Main bearing 3. Driving part 4. Rotational part 5. Outlet hopper

6. Gear coupling 7. Reducer 8. Flexible coupling 9. Main motor 10. Slow drive device

6 7 8 9 10

1 2 3 4 5

BBI4796 型磨煤机示意图

1.进口料斗 2.主轴承 3.传动部 4.回转部 5.出口料斗 6.齿轮联轴器 7.减速

机 8.弹性联轴器 9.主电机 10 慢速驱动装置

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4.1.2 Main Technical Performance

4.1.2.1 Coal Pulverizer Type: BBI4796

Coal pulverizer cylinder effective inside diameter: 4650 mm

Coal pulverizer cylinder effective length: 9740 mm

Application: for boiler coal pulverizing system of coal-fired power generation unit

Pulverization method: steel balls impact and grinding together with hot air blowing and drying

Input particle size: ≤25 mm

Coal pulverizer name plate output: 100 t/h

Cylinder rotate speed: 13.18 r/min

Max. Load of steel balls: 256 t

Cylinder effective volume: 165.3 m3

Feed port size: 1140×1300 mm

Size of outlet hopper air ventilation port: 1069 ×1740 mm

Size of outlet hopper powder discharge port: 1288 ×1740 mm

Exposed gear: Module:28; large gear Tooth number :250; small gear Tooth number :31

4.1.2.2 Main motor:

Type: YTM900-6

Power: 3500 kw

Voltage: 6600 V

Rotate speed: 986 r/min

Efficiency: 50HZ

Electric heater voltage, single phase,230V, power 1200×2 W (used for shutdown)

Main motor lubrication oil dilution station (XYZ-20):

Nominal pressure: 0.5 mpa; nominal flow:20 L/min

Original lube oil: 450 L

Lube oil brand: 46 steam-turbine oil L-TSA

Cooling water consumption: 2.5 m3/h

Power: 1.5 kw ; voltage: 400 V; rotate speed:1400 r/min

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4.1.2.3 Main reducer:

Type: ML2PSF150

Speed ratio: I = 9.275

Lubrication method: reducer with independent oil dilution station for forced lubrication

Power: 11 kw

Voltage: 400 V


Lube oil brand: ISO VG320

Cooling water consumption: 8 m3/h

4.1.2.4 Slow drive device:

Planetary reducer (with brake motor):

Type: NMCD560-125

Speed ratio :i＝125

Motor type: YEJ280S-6(B35)

Motor power: 45 kw

Motor rotate speed: 970 r/min

Motor voltage: 400 V

Pan Mill rotate speed: 0.105r/min


Lube oil brand: intermediate extreme pressure industrial gear oil N220(GB5903-86)

4.1.2.5 Main bearing HP/LP lubrication oil dilution station:

4.1.2.5.1 Type: GDR-60/10/170


Lube oil brand: SO VG460

Cooling water consumption: 18 m3/h

Electric heater: totally 6(400VAC/3kw × 6)

4.1.2.5.2 LP oil pumps (1 set):

Nominal flow: 170 L/min

Nominal pressure: 1 mpa

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LP oil pump motor (1 set):

Power: 7.5Kw; voltage: 400 V; rotate speed:1440 r/min

4.1.2.5.3 HP lifting oil pump(1 set):

Nominal flow:4X15 L/min

Nominal pressure:20mpa

HP lifting oil pump motor(1set):

Power:30 kw; voltage:400 V; rotate speed:1470 r/min

Electric strip heater:230VAC/kw

4.1.2.5.4 HP lube oil pump (1 set):

Nominal flow:2×5 L/min

Nominal pressure: 10mpa

HP lube oil pump motor (1set)

Power:3 kW; voltage:400 V; rotate speed:1440 r/min

4.1.2.6Exposed gear oil jet lubrication device:

Type: GSPZ-Z-8

Working air pressure: 0.4~0.6 mpa

Max. Air pressure: 0.8 Mpa

Max. Oil delivery: 1500 g/min( air pressure 0.6mpa)

Air supply capacity: 0.42 m3/min

Working oil pressure: 20 mpa

Nozzle number: 8

Tooth width 850 mm

Lube oil brand: NLG100-0

4.1.2.7 Large gear sealing air unit

Fan type: CQ3-J

Flow: 800 m3/h

Pressure: 590 pa

Motor power:0.37 kw

Motor voltage: 400 V

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Motor rotate speed:2900 r/min

4.1.3 Steel ball coal mill maintenance

4.1.3.1 Reducer maintenance

Maintenance item


Maintenance of reducer casing

1. Disassemble and clean parts; check joint surface and oil system.

2. Check bearing, gear and teeth engagementas per common standard for rotating machine.

3. Carry out hydrotest for cooling water pipe.

4. Replace qualified lube oil.

1. The contact between reducer cover and flange should be airtight oil system should be securely installed without oil leakage. 2. Manually turn the reassembled reducer; the shaft should rotate freely with stable engagement.

3. Test pressure should be 7-8Kg/ cm2.

Maintenance of oil system:

(I) check and cleaning of oil system

1. After assembling oil system, completely cleanand blow the accessories (oil tank, oil pipeline,oil filter and oil cooler, etc.)To remove debris,dirt or paint soluble to lube oil before close thesystem; do not open the system or make anyopening without permission.

(II) installation of oil tank

1. After installation of oil tank, check for anyseepage. (carry out kerosene seepage test atthe welding seam between oil tank and relativeconnecting pipe)

2. Steam heating pipe or cooling water passesthe hydrotest.

3. Installation oil level gauge.

4.carry out oil-immersing check on the buoy

5. Installation oil level ruler.

1. After installation, oil tank should be free of leakage.

2. Test pressure should not be less than 1.25 times of the Max. Working pressure of the medium.

3. Oil level gauge should be equipped with obvious and qualified oil level indicator. 4. Oil-immersing check should be free of leakage. 5. Ruler should be vertical.

(III) installation of oil pipe

1. Routing of the pipeline should be orderly andreliable; do not embed the oil pipe in soil orconcrete.

1. Pressure oil pipe and oil return pipe normally have an inclination of 2%.

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Maintenance item


2. Carry out leak test on valves in oil pipeline.

3. Padding of the joints between oil pipe andassociated parts should not extend to the innercircle of the pipe; the thread joint should besealed by hemp thread and white paint.

4. Plane flange should be welded on both sides.

5. Check the oil sight glass and oil adjustingdevice of bearings of ball mill.

2. There should be noleakage.

3. Joints should be airtight.

4. Welded junction is free of sand hole and crackle.

5. Oil sight glass is clear and oil adjusting device operates freely and properly.

(IV) oil cooler installation

1. Check oil cooler oil side, water side.

2. Hydrotest should be performed for oil cooler.

1. Both oil side and water side should be clean and smooth; joint surface is free of leakage

2. Test pressure should be 1.25 times of the HP side pressure.

(V) gear oil pump check and installation

1. Visually check the oil pump for any defect,and check engagement of the gear.

2. Check the connection flange of end coverand casing.

3. Measure clearances of parts.

1. Oil pump is free of defect by visual inspection. Oil pump gear engagement should be stable and well touched.

2. Connection flange should be airtight.

3. Requirements of technical specification should be satisfied.

(VI)oil circulation 1. Install oil filter on the oil return header nearthe oil tank.

2. Temporarily connect the pressure oil pipe and oil return pipe of bearing during oil circulation toprevent oil from passing through bearing.

3. Startup oil pump to establish normal workingoil pressure before oil circulation and check oiltightness. Oil circulation should continue untilno debris on the screen. All parts should be tight

1. Mesh of the oil filter is 0.5- 0.7mm normally.

2. Mesh should be 0.30 mm.

3. There should be no rust on the white cloth.

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Maintenance item


without leakage.

4. Oil used for oil circulation is normal workinglube oil.

5. After oil circulation, recover pipeline andremove debris inside oil tank; refill qualified lubeoil; then carry out oil circulation for the bearing. Adjust oil volume to evenly coat the neck journalwith oil but the gland seal should be free of oilleakage.

6. Install screen at the inlet oil pipe to thebearing during oil filling test and test run.

7. During oil filling test, adjust the oil pressure relay and safety valve as per technicalspecification.

8. For dirty oil pipe, immersing acid cleaning isrecommended. After acid cleaning, blow withsteam and check inside of the pipe with whitecloth.

4.1.3.2 Maintenance of drive gear

Maintenance item


(I)large/small gear check and alignment

1. Remove gear seal housing and wash it.

2. Wash large gear and check for any crackle, burr, depressed points or tooth falling. Check the gear abrasion and teeth space by Template or tooth calipers.

3. Check parallelism of the centerlines of large/small gears.

4. Check the radial and axial vibration degree of the large gear with dial gauge.

1. Gear seal housing should be clean without oil.

2. When the abrasion thickness of the chordal tooth on gear pitch circle reaches 5 mm, turn it around for operation. When another 5mm is worn, replace it..

3. Non-parallelism of centerlines of large/small gear should not be larger than 0.2 mm.

4. Radial and axial run-out

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Maintenance item


5. Measure addendum cone and gear backlash, the number of measurement points for gear backlash should be no less than 8. Record the average value of clearance between working face and non-working face.

6. Check the contact of large/small gear working faces by color printing and correct the gear deformation.

7. Check the engagement of the two semicircles of the large gear and check the holding bolt on the joint surface between the large gear and large tank flange. Tighten it if necessary.

tolerance of the large gear ring should satisfy the following requirements:

radial swaying pitch ① ≯

circle diameter×0.25 mm.

axial swaying pitch ② ≯

circle diameter×0.35 mm.

5. Requirements not the engagement of large/small gear are:

① addendum cone clearance should be 6~8 mm.

gear backlash should not ②

be less than 1.40 mm, and greater than 2.18 mm(when width between centers is greater than 2000-3150mm)

clearance error of the ③

working face along tooth width is 0.15 mm. ≯

6. Along tooth height is not less than 50% and 60% along tooth width.

7. Joint bolt should be tightly secured without any rupture or missing. Gear ring and flange should be well contacted, joint surface clearance formed by gear rings should be 0.1 mm.≯

(II) replace large gear or its working face(turn it

1. Completely measure the large gear to be replaced and record the result.

2. Remove seal housing above the large gear.

3. Turn the joint part of the two semocircles of the

1. The record should be accurate and complete.

2.

3. The contact ratio between

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Maintenance item


around) large gear to horizontal position. Lift the upper semicircle by crane and securely drop it down after disassemble all joint bolts. Avoid significantly swaying during disassembling.

4. Turn the large tank 180 degree and drop down the other semicircle.

5. Premount the semicircles of the new gear on ground. Check the contact of the the two semicircles with red lead oil and contact ratio of the locating stud and cylindrical bore.

Clean the oil, rust, and burr on the gear and flange joint surface before mounting

6. Measure tooth profile and teeth space of the new gear with template and gear tooth calipers.

7. Lift and install the first semicircle of the new gear to large tank.

8. Turn the large tank 180 degree to install the other semicircle. Put in locating studs and bolts of the joint surfaces of the two semicircles.

9. Put in joint bolts of the large gear and large tank flange.

10. Check the contact of large gear joint surface with filler gauge and adjust it if necessary. And then one by one tighten the joint bolts of two semicircles joint surface between the large gear and large tank.

11. Measure axial and radial swaying of the gear with dial gauge. Evenly divide the large gear into eight pats slowly turn the large tank, and one by one measure the axial and radial swaying at the eight dividing points (measure again for review). Carefully record the results.

If the radial swaying degree does not satisfy standards, radically adjust the large gear along

the locating stud of the joint surface of the two semocircles of the large gear and the cylindrical bore should be larger than 80%. Contact ratio of the two joint surfaces of the large gear should be larger than 75%.

4.

5.

6. New gear tooth profile and size should satisfy the requirements of the manufacturer drawings.

7.

8.

9. When measure the two semicircles joint surfaces of the large gear with 0.05 mm filler gauge, there should be no space to insert. Holding bolt should be free of loose and missing.

10. Radial and axial run-out tolerances should satisfy the following requirements:

(1) radial swaying value is 1 mm.≯

(2) axial swaying value is 1.2 mm.≯

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Maintenance item


large tank flange. If the axial swaying degree does not satisfy standards, add wedge shim at the joint surface of the large gear and large tank flange to adjust it.

12. When both the axial and radial swaying degrees satisfy requirements, put locating studs into large gear and large tank flange. If the pin holes do not match with studs, mill the hole again.

(III) measure clearances of small gear parts

1. Disassemble bearing upper cover, and visually check bearing.

2.measure the following clearance by filler gauge or pressing lead wires:

Radial clearance between ① balls and bearing inner and outer steel rings .

Axial and radial clearances between bearing ②

Outer ring and casing.

Axial clearance between thrust end and ③

expansion end bearing.

1. Bearing should be free of corrosion or crackle.

2. Radial clearance is between balls and bearing inner and outer steel rings should be 0.15~0.30 mm.

Radial clearance between bearing outer ring and bearing upper cover should be 0.05~0.10 mm.

Thrust end axial clearance should be 0.05~0.10mm; expansion end axial clearance should be 3~5 mm.

(IV) disassemble small gear

1. Check engagement of the large/small gear for any match marking; mark if necessary.

2. Lift out small gear and put it on a prepared support. Do not damage the ball bearing when disassembling small gear.

1. Match marking should be clear and complete.

(V) maintenance small gear

1. Clean small gear and neck journal with kerosene.

2. Check gear abrasion and teeth space with template or gear tooth calipers; knock gears one by one to check for any crackle.

3. Correct the deformation on the tooth surface.

1. Turn around the gear pitch circle when tooth thickness abrasion reaches 3~5 mm and replace it when another 3~5 mm is worn. 2. Gear shaft should be free of crackle. Shaft tortuosity should be <0.1 mm,

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Maintenance item


4. Shaft should be free of crackle and loosing. If abnormal noise is found during operation, measure tortuosity of shaft, ellipticity and conicity of the neck journal and record the results.

5. Check hardness of the small gear teeth and decide whether to anneal the surface based on the gear abrasion.

ellipticity <0.03 mm and conicity < 0.015mm.

3. Quenching hardness of the small gear surface Rc should be 40-45. Quenched case depth should be 15 mm.≮

(VI) check ball bearing

1. Check balls, balls retaining support and inner/ outer steel ring for any crackle, peeling and stain; check abrasion of the retaining support.

2. Check the match of the ball bearing inner steel ring and shaft.

1. Balls should be free of crackle and serious stain. Balls windage should be <0.30 mm. Keeper and inner/outer steel rings should be free of crackle. Replace keeper when its abrasion exceeds 1/3 of its thickness.

2. The assembling of ball bearing inner steel ring and shaft should not be loose and should have a stress of 0.01-0.03mm.

(VII) replace ball bearing

1. Disassemble ball bearing with special tools.

2. Grind the rust and burr on the neck journal by abrasive cloth or oil stone.

3. Check parts of new bearing for any crackle or rupture and measure windage of balls.

4. Measure the mating dimension of inner ring of new bearing and neck journal.

5.put the bearing into lube oil and heat it unto 100-120 and quickly put into the original position ℃

on the shaft against the shoulder (no clearance) for natural cooling.

1. Parts of new bearing should be free of crackle and rupture. Windage of balls should be uniform and

0.3 mm.≯

2. Tightening force between bearing and shaft should be 0.01~0.03 mm.

3. After cooling, ball bearing should be rotated freely by hand.

(VIII) check and replace bearing

1. Check whether gland packing is flat, soft and elastic, and check for any crackle,.

2. Check abrasion of the gland packing and the

1. Seal packing should be flat, soft and elastic without breach.

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Maintenance item


packing contact with shaft. Replace outworn parts. 2. Contact of the seal packing and shaft should be tight but not over tightened (1 mm of overtghtening is allowable).

(IX) assembling of small gear

1. Lift the assembled small gear with lifting tools onto the bearing housing.

2. Place the small gear as per matching mark. Align the small gear as per addendum cone and gear backlash.

3. Check engagement of the large/small gears with red lead powder.

4. Measure the radial clearance between ball bearing outer steel ring and bearing cap with filler gauge or pressing lead wires.

1. Stress between the small gear and shaft should be 0.03~0.05 mm. 2. Gear backlash of the engagement between large/small gears should be 0.75~1.5 mm. Difference between the measured gear backlash values on both side should be

0.05~0.10 mm.≯ 3. Contact area of the large/small gears should be ≥75%.

(X) installation bearing cover and gear seal housing

1. Move the small gear to make thrust ring cling to thrust shoe; install bearing cap and symmetrically tighten bolts.

2. Repair deformation and rupture of the gear seal housing.

1. Surfaces of the upper and lower bush cover thrust should be on the same level.

2. Seal housing should intact without deformation; connecting screws on the cover should be tightly engaged; flange should be flat and tight without oil leakage.

Packing seal should be properly tightened.

Seal housing should not crash with the gear.

(XI) check and tighten anchor bolt

1. Check anchor bolt for any loose or rupture.

1. Anchor bolt should be free of loose, rupture and missing.

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Maintenance item


2. Check nut for any loose with wrench. Should tighten it with lock nut if necessary.

2. Bolt should be well tightened without loose.

4.1.3.1 cylinder and lining plate maintenance

Maintenance item


, maintenance Ⅰ

of steel ball coal mill

(I)pour out steel balls

1 startup coal pulverizer and mill exhauster to run without load for 15 minutes to exhaust residual pulverized coal in the cylinder.

2. Remove inlet hopper, securely install the tools for scrapering out steel balls and the screen for separating steel balls.

3. Startup coal pulverizer; steel balls in the bucket will go into the screen when the large tank rotates. By the screen, large and small steel balls( and scrap iron, debris) are separated and transmitted to the outlets .

4. Small steel balls and scrap iron, debris will be delivered to a specified location.

5. Handle the qualified steel balls to a specified stack yard.

1,inside of cylinder should be free of powder accumulation

2, installed equipment should be secured reliably.

3, steel balls with a diameter less than 20 mm should be out of service.

(II) maintenance of the inlet/ outlet hoppers

1. Measure the abrasion of the hopper guarded plate.

2. To prolong the service life of the outlet elbow the two following measures are recommended:

(1) Install a wearing steel plate of 10 mm at the bottom of the elbow. It can work for a minor overhaul period.

(2) Grout alumina cement in the elbow. Weld hook nail at the back of the elbow and coat it with steel wire gauze; then grout alumina cement of 50 mm and care it for a week. It won’t be worn out during two years by this means.

1, when the abrasion of the hopper guarded plate exceeds the 2/3 of the former thickness, replace it. Partial abrasion should be repaired and the surface should be kept flat.

2. Inner surface should be kept flat.

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Maintenance item


(III) disassemble coupling and studs

1. Check coupling for any match marking.

2. Check coupling bolts. Coat it with butter or black lead powder after derust; tighten the nuts; it should be carefully stored after matching.

1, match marking should clear intact.

2, bolts and nuts should be free of crackle; thread should be intact.

(IV) check steel tiles and holding screw

1. Check abrasion and crackle of the steel tiles.

2. Manually knock the steel tiles bolts to check their tightness.

1. If the abrasion of steel tiles exceeds the 2/3 of the thickness, it should be replaced. Replace steel tiles with crackle and unable to be repaired.

2. Bolts after tightening should satisfy requirements without loose.

(V) replace steel tiles

1. When replace all or part lining tiles, I beam overhead crane should be installed for steel tiles entering or leaving large tank and completely check the large tank.

2. Review the external dimension of the new tiles as per drawings and check their connection; number the steel tiles and record.

3. When replace steel tiles, turn the steel tiles bolts to the horizontal positions; then dismount the lower steel tiles. During installation, lay asbestos slate with a thickness of 5-10mm between the tank and lining plate; Concave-convex joints of the steel tiles should be tight; adjust clearance of the steel tiles with tommy bar; do not cut the steel tiles without permit. Because the abrasions of the steel tiles at the inlet and outlet surface are different, exchange the tiles after a period of operation.

4. Press the steel tiles with wedge iron block and tighten bolts before turn the large tank 180 degree. Dismount the other part of the

1. Large tank should be free of crackle and plumping.

2. New steel tiles should be free of crackle and casting defects, their sizes should satisfy requirements.

3. Laid asbestos slate should be uniform and the joint seam should be tight. After installation, steel tiles and large tank inner wall should contact completely. Clearance of steel tiles should be kept uniform.

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Maintenance item


steel tiles as per above said procedures. Lowly turn abround the large tank to avoid centre-of-gravity shift of the large tank.

5.during construction, to avoid rotation of the large tank, motor of the slow drive device should be shut down. Staff should be appointed for monitoring and protection; weld temporary support at the outer wall of the large tank.

6. After replace new tiles,install steel balls in groups. The quantity of the balls install at the first time should be 20-30% of total. Number of each group should not exceed 20% of total. After each installation, operate for 5 mionute without load and tighten again the steel tiles bolts; after 72 hours operation, retighten them again; the same check should be performed at each minor overhaul.

(VI) check tank end cover and associated bolts

1. Check tank manhole for any crackle; repair it if necessary.

2. Check the root of the end cover bar and bolts for any crackle; repair or replace it if necessary.

3. Verify joint bolts of large tank and end cover are properly tightened.

4. Verify joint bolts of the geared ring and tank are secured.

1. If penetrable crackles exist with a number exceeds the 1/3 of total bolt, replace it.

2.

3. Bolts should be free of defect and joint bolts should be well tightened.

4. Bolts should be free of defect and joint bolt should be well tightened.

(VII) jack up tank, disassemble bearing bush and check(only for abnormal case during operation)

1. Dismount the large bush cover and lift it the work piece and record.

2. Measure and record the clearances between large bush and parts of tubular journal.

3. Jack up the large tank until the large bush

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Maintenance item


can be turned out. Crosstie and taper liner should be put below the large tank when jack it up. Jacking should be slowly performed and tank shift should be avoided.

4. Lift the large bush with hoist by binding it with wire cables; then turn around tubular journa. Do not damage the surface of the bearing pad.

5. Cover the tubular journal with white cloth and plastic cloth.

(VIII) check and rescraping of the main shaft bearing pad and tubular journal

1. Wash the surface of the bearing pad with kerosene; check bearing pad for any crackle, sand hole and burnt part; knock the bearing pad ot check for any shelling. Bearing pad can be repaired with babbitt.

2. Rescraping of the main shaft bearing pad:

(1) Mark a 75 degree rim anglenoundary on the bearing pad.

(2) Evenly rescrape off 0.01~0.03 mm outside the secondary boundary.

(3) Rescrape the bearing pad within the range of rim angle.

(4) Rescrape off 0.03~0.05 mm from the boundary to the position 15 mm from the secondary outer side.

(5) Move outwards 15 mm gradually and rescrape off 0.03~0.05 mm until the centering surface.

(6) Rescrape the stepped clearance to wedge clearance.

(7) Rescrape the bearing bore to an ellipse.

3. Tubular journal should be checked in

1. Bearing pad should smooth and intact without any crackle or pocking mark. When the shelling area of the bearing pad exceeds specified value, repair it. No shelling in the range of rim angle is allowable.

2.1 Rim angle of the large bush should be in the range of 70°±5°.

2.3 Bearing pad and neck journal should be contacted evenly; check by means of color printing and there should be at least 1~2 points on every square centimeter area. Contact area should be over 85%. The contact point should be hard and clear. Position without points should be rescraped 2-3 times more for better lubrication.

2.4 Sun of the clearances of the bearing bores normally should be 1.5~2/1000 of the diameter of the neck journal;

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Maintenance item


aspect of :

(1) Check diameter of the hollow tubular journal.

(2) Check the flatness of the tubular journal surface along axial direction. Axially stick the ruler to the shaft surface to be parallel to centerline of the the shaft. Then check filler gauge. The measured difeerence between concavo and convex parts of the shaft is the flatness error. Grind the surface if the error exceeds limit.

(3) Check ellipticity of the tubular journal which is half of the deference between long shaft diameter and short shaft diameter.

(4) Check conicity of the tubular journal.

(5) Check the damage and corrosion of the tubular journal surface. When the partial damage or corrosion is within the following ranges: width less than 5 mm, length less than 100 mm, diameter less than 15 mm, pit depth less than 0.2 mm, rust spot depth less than 0.2 mm and total corrosion area less than 5% of the neck journal working face area, treat it with oil stone or abrasive cloth or grinding tools for neck journal. If the glossiness is low, treat it with polishing method.

(6) Check the nonconcentricity of the two sides of the neck journal. Centimeter also can be used to check on the main bearing end face and the runout value should be less than those specified in the right table.

4. Clean, check main bearing spherical bush.

Spherical bush is the key part of the coal pulverizer and should be checked strictly; ensure the spherical bush and spherical seat contact securely and evenly. It works agilely.

and there should be a ligulate oil drain clearance.

3.1 Diameter error of the tubular journal should be less than 0.15/1000 of the designed diameter.

3.2 Flatness errors should be less than 0.05 mm.

3.3 Ellipticity should satisfy the requirements of equipment technical documents and not greater than 0.2 mm.

3.4 Conicity should satisfy the requirements of equipment technical documents and not greater than 0.2 mm.

3.5 Surface should be smooth (required to reach R=7μm) without rupture or rust.

3.6 The main runout value of the bearing surface is shown in the right table.

4. Bearing sphere action agilely with good contact. Check by means of color printing and there should be no less than 1-2 points on one square centimeter, and the contacting area should not be less than 75%. On the two sides of the contact surface, there should be a wedge clearance as shown below:

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Maintenance item


Check the contacting by means of color printing method. Contact points should be hard; scrap 2 or 3 more times the position without color point; grind the upper and lower contact surfaces of the spherical bush with #00 fine sand cloth to improve surface glossiness and reduce friction. Coat the surface with butter after rescraping.

5. Clean main bearing 的 inner wall, upper cover, oil sink, oil hole and oil return hole.

Hydrotest should be carried out for the main bearing water chamber.

6. Currently temperature of the measuring points at the coal pulverizer bearing pad can not correctly represent the temperature of bearing pad babbitt. The reason is the babbitt can not be directly measured. So it should be checked. Directly weld the measuring points on the joint of the iron and babbitt to actually measure the babbitt temperature.

Note: depth a should be 20-25 mm, edge clearance c should be 0.20-1.5 mm.

5. Completely clean cavities, oil sink and inner wall to ensure the smoothing of the oil pipe. Hydrotest pressure should be 1.25 times of the working pressure of the cooling water.

(IX) recover ball mill

1. Clean large bush surface, spherical bush (seat) and tubular journal and coat butter on the spherical bush. Before lower down the tan, put three dial gauges on the main bearing foundation to measure the variation of the three points on the left, middle and right of the lower bottom surface of the main bearing before and after tank location bearing.

2. Lift the large bush with two hoists and turn it below the hollow shaft along the direction of the tubular journal and locate it as per matching mark. When descend the large bush, it should be ordered by an appointed person; check the clearance around the bush and tubular journal every 10 mm descending until it is securely located

1. Elevation error of the main bearing should be ±10 mm; ≯

horizontal error of two bearings should be 0.5 mm/m; ≯

distance error between bearings should be 0 mm; ≯

distance between two bearings should be determined as per actual size of the tank and take into consideration of the hot expansion; bedplates of two bearings should be parallel with a diagonal error 2 mm; ≯

longitudinal and transverse horizontal error of bedplate should be not greater than 0.1/1000 of its length and

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Maintenance item


bush surface should be protected from damage during installation. Align the bearing after location and measure the horizontal error of the two bearings.

3. Before location of tank, completely clean bush surface and oil sink. Before large tank is lowered down to the surface of large bush fill in #100 lube oil of 1-2 liters along tubular journal to protect large bush surface.

4. Locating tank should be carried out stably and two ends should be in place at the same time. After location of the tank clearances should satisfy the following requirements:

(1) Marking line on the templates on the two side of the tubular journal should be aligned with the positions of the left, middle and right related to the large bush:

Chinese English

左 left

中 middle

右 right

(2) Clearance between bearing pad and hollow shaft radial:

width.

2. Centers of the spherical seat spacer pin and spherical bush spacing hole should be aligned; bearing should be kept level at the directions of longitudinal and transverse; horizontal error of two bearings should be 0.5 mm.≯

4.1

4.2 Radial clearance a, b, c, d should be equal.

4.3 Large tank horizontal error should be 0.50 mm.≯ 4.4 tubular journal and large bush two sides clearance should satisfy requirements in the following table:

Thickness of filler gauge (mm)

Insert length

(mm)

0.15 600-650

0.50 500-550

0.75 400-450

1.00 300-350

1.25 200-250

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Maintenance item


(3) Measure levelness of the large tank.

(4) Measure the wedge clearance between tubular journal and two sides of the large bush with filler gauge.

(5) After tank in place, check and adjust the axial expansion clearance and thrust clearance.

4. Install the packing seal at the bearing bore and then the large bush cover.

4.5 Recommended value for the expansion clearance of the supporting bearing is shown in the following table:

Chinese English

轴颈 neck journal

轴承 bearing

Total thrust clearance error is ±0.15 mm.

Thrust clearance is 0.2~0.4 mm normally.

4. Bearing bore should be tight without seepage.

(X) check and clean cooling water system

1. Check cooling water pipe and clean the blockage (if any), then blow it with compressed air.

2. Maintenance of flanges and valves.

1. Cooling water pipe should be free of blockage and leakage.

2. Flange is intact and operation of valve is agile and it is tight without leakage.

(XI)dismounting and installation of sound insulation of the large tank

1. When replace steel tiles, remove all sound insulation layers and check it.

2. When repair the cover plate or bolts of the sound insulation layer by means of gas

1. Sound insulation layer should be tight with a thickness of 40~70 mm. 2. When recover sound insulation layer, they should be laid orderly. Stress on bolts

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Maintenance item


welding, remove a part of felt of the internal sound insulation or water the parts to be cut/welded to avoid fire.

should be uniform and bolts should be sufficient.

(XII) installation of steel balls

1. Install the tools for installing balls and put in a certain number of balls with certain sizes as per adjusting results or specifications.

1. Steel balls with a diameter less than 25 mm and debris should be kept out of coal pulverizer; application of steel balls made by cast iron should be prohibited.

(XIII) recover large tank inlet/outlet elbow and sealing device

1. Recover inlet/outlet elbow, measure and record the axial and radial clearances between elbow and hollow sleeve.

2. Recover sealing device and tighten all bolts.

3. Install sheet iron of the explosion door and coat it with a layer of white paint. Put asbestos cord with diameter of φ5 mm on the flange of the explosion door before install sheet iron and tighten bolts.

The matching of the hopper and hollow sleeve should satisfy the following requirements:

Unit

Thrust side

Expansion side

Axial clearance

Mm

<3 ＞15

Radial clearance

Mm

1~4 1~4

Center error

Mm

<1 <1

2. Flange bolts should be intact and well tightened. Contact of packing and sealing pad should be tight with uniform clearance around.

3.sheet iron of the explosion door should be made by tinplate or white iron with a thickness of 3-0.5 mm.

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Maintenance item


(XIV) check wedge and anchor bolts of the bedplate

1. Manually knock the bedplate to check for any crackle and use magnifier if necessary.

2. Check wedge for any loose. Pin can be used by drilling hole to avoid displacement.

3. Manually knock the anchor bolts to check for any crackle, rupture or loose. Tighten it if necessary.

1. Bedplate should be free of crackle.

2. Wedge should be free of loose. 3. Anchor bolt should be free of crackle or other defects and well tightened

IV system test run:

(I) prerequisites for ball mill test run

1. Installation, oil circulation and filling oil test have completed.

2. Oil pressure interlock test of ball mill and oil system has completed.

3. Test run should be performed as per specified technical specifications prepared before test run.

4. After no-load test run of motor is accepted, run for two hours together with reducer.

(II) startup requirement for ball mill

1. Startup oil system and adjust it to normal operation.

2. When tank is properly started up, shut it down through emergency button. Checkmain bearing and driver for any abnormal condition and begin no-load test run.

3. Before install steel balls, 8 hours no-load test run should be accepted. Installation of steel balls should be performed as per equipment technical specifications and should satisfy the following requirements:

Steel balls should be weighted.①

Balls should be installed by groups. The ②

quantity of the balls install at the first time should be 20-30% of total. Number of each group should not exceed 20% of total a test run should be carried out after each installation of balls to evenly distribute the

1.

2.

3.New steel balls should be the following percentage:

Φ40 mm 30%

Φ50 mm 35%

Φ60 mm 35%

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Maintenance item


balls; record the vibration value of parts and motor current.

Stop installation of the balls if any ③

abnormal condition is found; continue test run after faults are cleared.

After test run of balls installation, check④ the engagement of the large gear and then tighten lining plate bolts one by one.

(III) measurement and check during test run

1. Measure vibration of parts.

2. Measure temperature of parts.

3. Check the leakage of bearings.

1.1 Two bearings of the motor: 0. 05- 0.10 mm.

1.2 Two bearing of the reducer:

0.08-0.12 mm.

1.3 Two bearing of the small gear:

0.08-0.15 mm.

1.4 Large tank and large bush: 0.05-0.15mm.

2.1 Large bush bearing pad temperature should be 50 .≯ ℃

Temperature of the mixed return oil should be 40 .≯ ℃

2.2 Bearing temperature of the small gear reducer should be 70 .≯ ℃

2.3 Bearing of parts should be free of oil leakage.

Main maintenance tools and spare parts for steel ball coal mill

(I) Main maintenance tools:

Micrometers for inner and outer diameters, centimeter, large hammer, four 50 tonnes spiral jacks, two supporting seats (for jacking large tank), special tools for turning bearing pad.

(II) User drawings and information list:

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Serial No. Code Name Pages

1 K4419.00 SM BBI4796 steel ball coal mill (left) 2

2 K4419.1.0 SM Foundation and embedded part (left) 1

3 K4419.2.0 SM Drive part (left) 1

4 K4419.2.1.0 SM Small gear assemble 1

5 K4419.2.2.0 SM Large gear device 1

6 K4419.2.3.0 SM Slow drive device (left) 1

7 K4419.3.0 SM Cylinder part 1

8 K4419.4.0 SM Lining plate part (left) 1

9 K4419.5.0 SM Main bearing part A 1

10 K4419.6.0 SM Feed hopper part (left) 1

11 K4419.7.0 SM Inlet spiral pipe (left) 1

12 K4419.8.0 SM Inlet spiral pipe 1

13 K4419.9.0 SM Outlet hopper part 1

14 K4419.10.0 SM Large gear cover 1

15 K4419.11.0 SM Noise enclosure (left) 2

16 K4419.11.1.0 SM Noise enclosure bottom plate(left) 1

17 K4419.11.2.0 SM Noise enclosure frame (left) 2

18 K4419.12.0 SM Large gear sealing air device (left) 1

19 K4419.13.0 SM Main bearing lube oil system 1

20 K4419.14.0 SM Main motor lube oil system 1

21 K4419.15.0 SM Ball washer 1

22 K4419.16.0 SM Main bearing part B 1

23 K4419.21.0 SM General chart reducer and its oil station 1

24 K4419.22.0 SM General chart of reducer and its oil station 1

25 K4419.23.0 SM Main bearing lube oil station installation drawing 1

26 K4419.24.0 SM Chematic diagram of Main bearing lube oil station

system 1

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27 K4419.25.0 SM Main motor lube oil station installation drawing 1

28 K4419.26.0 SM Schematic diagram of the main motor lube oil

station systems 1

29 K4419.27.0 SM Large gear lube oil spray system drawing 1

30 K4419.29.0 SM Crowned teeth coupling 1

31 K4419.30.0 SM T type spring coupling 1

32 K4419.31.0 SM Motor list (each mill) 1

33 K4419.32.0 SM List of high strength bolt (each mill) 1

34 K4420.00 SM BBI4796 steel ball coal mill (right) 2

35 K4420.1.0 SM Foundation and embedded part (right) 1

36 K4420.2.0 SM Drive part (right) 1

37 K4420.2.1.0 Slow drive device(right) 1

38 K4420.3.0 SM Lining plate part (right) 1

39 K4420.4.0 SM Feed hopper part (right) 1

40 K4419.5.0 SM Inlet spiral pipe (right) 1

41 K4420.6.0 SM Noise enclosure (right) 2

42 K4420.6.1.0 SM Noise enclosure bottom plate (right) 1

43 K4420.6.2.0 SM Noise enclosure frame (right) 2

44 K4420.7.0 SM Large gear sealing air device (right) 1

45 QK4419.00 Electrical drawing information 75

46 KF4419.00 SM List of spare parts and special tools for BBI4796 steel ball coal mill

12

4.2 Coal Feeder

4.2.1 Coal Feeder Technical Specifications

Coal feeder is made up of body, feeding belt mechanism, chain scraper, weighting mechanism, signal unit for coal blockage and lack, lubrication device and electrical conduits, control cabinet and power supply cabinet. Coal enters coal feeder from raw coal hopper via coal gate, and is transported by belt to the outlet of feeder. Two weighting carrier roller are installed inside coal feeder forming a weighting span. A weighting roller is at the middle of the weighting span, equipped with load sensor. A speed sensor is installed on the main belt for measuring transporting speed and calculating coal feeding volume.

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Coal feeder main technical parameters:

RMSD100 type, output 30~110 t/h

4.2.2 Coal Feeder Maintenance

Maintenance item



1. Cut off power supply of coal feeder and close inlet gate.

2. Open the front and back door of the coal feeder; clean raw coal adherent to the coal feeder belt; start up chain cleaning mechanism to clean the accumulated coal at the bottom of the coal feeder tank.

( II) Disassemble tension roller

Loose the tension bolt of the tension roller to the largest position. Remove the grease hose of the tension roller.

2. Remove weighting sensor weighing rollers.

3. Place a cushion block under the tension roller and remove the roller rail and the joint bolts of bearing housing and casing; pull out tension roller from the side door.

4. Remove and check bearing housing and bearing on the tension roller.

1. Loosing bolt should be carried out alternatively to avoid thread damage.

(III) Belt disassemble

After remove belt driving roller, draw out the belt from the outlet door of the coal feeder.

(IV) Assemble and adjust roller and belt

1. Place the belt into casing.

2. Install two sides’ tension roller arms together with sleeve and bolt onto the casing and secure it with cotter pin.

3. Connect the upper and lower lead rails with casing by bolts and install belt supporting plate on the lead rail.

4. Wash roller surface, roller bearing and

L roller surface should be smooth without any burr or defect.

2. Roller bearing should be free of abrasion or corrosive pitting.

3, tension arm sways agilely.

4. Two sides of the upper and

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bearing unit with diesel and check the above parts.

5. Put the bearing and bearing assembly onto the roller shaft.

6. Put sliding block onto the tension roller and put it onto the belt inside casing and locate it on the upper and lower lead rails.

Note: bearing housing is filled with #3 lithium saponify .

7. Installation tension stay bolt and bolt seat and then move the tension bolt to its long position.

8. Put the disassemble seat of the roller into the belt and casing and secure it.

9. Slide the drive roller into the casing and secure the roller onto the casing with bearing housing cap. Adjust the elevation of the roller by the adjusting nut on the bolt of the drop hanger.

11 insert the driven roller into the casing via maintenance hole on the side casing surface and locate it. When adjust tension bolt, tighten the belt to a suitable tension degree.

12. Assemble belt and clean the scraper.

lower sliding rail should be on the same level.

5. Sliding block of the tension bolt should move agilely in the lead rail.

6.

7.

8. There should be a clearance of 3mm between the half coupling on roller and that on reducer.

(V) assemble and adjust weighting mechanism

1. Wash weighting roller and roller bearing assembly with diesel.

2.Mount the roller and associated parts lick bearing , bearing housing onto the casing.

Note: bearing housing should be filled with #3 lithium saponify .

3. Unite the weighting roller and two sides bearing assembly.

Note: bearing housing should be filled with #3 lithium saponify .

1. Roller surface should be glossy without burr, and the supporting contact surface should be free of friction.

Roller should rotate agilely without seizing; axial runout value should be less than 1.5mm; runout value of the outer circle should be less than 1mm.

2. There should be not friction between the lipping of the belt

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4. Install weighting sensor at the two sides of the casing and secure it with nut. connect the assembled weighing rollers with the two sides weighting sensors with pin roll ; pin roll should be equipped with cotter pin.

5. Install the standard weighting calibration block on the weighting bearing housing with joint plate and pin and lock it with cotter pin.

Note: operating handle should rotate agilely; the joint plate of the standard weighting calibration block and bearing housing of the carrier roller should be clung to them without limit.

and weighting roller or weighting carrier roller.

(VI) disassemble reducer casing

1. Drain out lube oil inside the reducer casing and remove the coupling and motor from the casing.

2. Remove bolt s of the bearing circular gear seat of the reducer casing to dismount the bearing housing.

3. Remove angular tooth, nut and washer.

4. Remove bottom bearing housing; take out lube oil pump, spring and spring seat.

5. Remove circular gear and take off worm wheel shaft.

6. Remove angular tooth and front & back bearing housings of the worm wheel; take out worm wheel and remove worm wheel and bearings on the worm wheel.

Note: frame heating can be used to remove parts.

7. Take out worm wheel and bearing outer ring of the worm from bearing housing.

8. Take out oil seal from the worm bearing housing of the worm wheel.

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(VII) assemble reducer casing

1. Install the oil seal into worm wheel bearing housing.

2. Install the outer ring of the worm bearing and that of the worm wheel bearing into bearing housing.

3. Put the inner ring of the worm bearing and that of worm wheel bearing onto the worm and worm wheel shaft and knock them to the shaft shoulder.

4. Install the worm wheel into reducer casing and measure the windage.

4.3 Maintenance of the Auxiliary Equipment of the Coal Pulverizing System

4.3.1 Maintenance of the Raw Coal Bin and Pulverized Coal Bunker

4.3.1.1 Raw Coal Bin and Pulverized Coal Bunker Technical Specifications

Raw Coal Bin Technical Specifications

Boiler is equipped with two raw coal bins, which is the raw coal storing equipment of the coal pulverizing system. Its upper part is a rhombus shape rhombus with four wall inclination angle ≤30°; its lower part is a hyperbola metal coal hopper. After primary crashing by the coal crusher in the coal stack yard, raw coal is delivered to the raw coal bin for storage by the conveyor belt.

Structure of the raw coal bin is shown below:

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Fig 5-3 Structure of the Raw Coal Bin

4.3.1.1 Pulverized coal bunker technical specifications

Boiler is equipped with two pulverized coal bunkers, which are used for storing pulverized coal made by the coal pulverizing system. Its structure is similar with raw coal bin ;

To avoid powder accumulation, corners are made into arch-shape. It is sealed around and equipped with dehumidifying pipe, firefighting steam pipe, carbon dioxide pipe and explosion door on the ceiling together with powder level indicator. Pulverized coal separated by the fine pulverized-coal separator enters the pulverized coal bunker via air locker, wood scraps separator.

4.3.1.2 Raw Coal Bin and Pulverized Coal Bunker Maintenance

Maintenance of raw coal bin


(I) clean the bin Equipment department should contact the fuel department to clean the bin.

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(II) maintenance of the metal coal hopper

Check abrasion of the metal coal hopper, repair the position with over abrasion or leakage.

Thickness of the coal hopper steel plate should be 4 mm; after ≮

maintenance, raw coal bin should be free of leakage and abrasion.

Maintenance of pulverized coal bunker

Maintenance item


(I) preparation before maintenance

1. Prepare cleaning tools and small animals (chicken or duck).

2. Prepare lighting tools. To ensure safety, 12 V portable light should be used and insulation of rubber cable and lamp cap should be good. Before boiler shutdown, prepare steam and carbon dioxide firefighting equipment for emergency.

3. Pulverized coal bunker should be empty and work sheet has been issued.

4. Before cleaning, close valves of all pulverized coal chute and firefighting pipes and lock out and tag out.

5. Open manhole to vent naturally for 24 hours; the manhole should be enclosed by white/red strips.

6. Temperature should be kept below 40 ; attention ℃

should be paid to the temperature of the pulverized coal to prevent explosion caused by pulverized coal combustion.

(II) clean coal bin

1. Put the small animals inside the pulverized coal bunker for abut 1 hours to verify the environment is safe for staff.

2. Flammable matters and other debris are prohibited. Maintenance staff should wear special work clothes and shoe without iron. Safety belt should be Worn before enter the coal bin and the end of rope should be out of the coal bin; there should be two or more personnel responsible for monitoring and protection. Personnel should not enter the bin two or more at the same time; the time inside the bin should not exceed 10 minutes. Coal shovel for cleaning bin should be

1.

2. After cleaning, internal wall and corners should be free of accumulated pulverized coal.

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made by copper or aluminum to avoid causing spark.

3 personnel should well gas mask, safety spectacles and glove; cuff and bottom of trousers should be bound.

4. Check moisture absorption piping, firefighting steam pipe, and carbon dioxide pipe and explosion door.

5. During cleaning, if spontaneous combustion of pulverized coal is found, stop cleaning immediately and leave the bin quickly to close the bin and extinguish the fire.

6. Personnel of safety supervision department and medical staff should be on site during cleaning.

7. Before removal of pulverized fuel feeder, cleaning staff s should leave pulverized coal bunker.

3.

4. All should be smooth and intact.

(III) close manhole

1. After cleaning, check the amount of staff and tools avoiding foreign matters left in the bin.

2, manhole joint surface should be sealed with asbestos cord; flange bolts should be complete and evenly tightened.

3. Outer wall of the pulverized coal bunker missing insulation should be repaired.

1.

2. There should be no powder leakage.

(IV) calibrate powder indicator

1. Check the powder level indicator; it should be vivid with secure installation. Except operating rope, there should be safety rope on the powder indicator.

2. Check adjusting height of the powder indicator

3. Check wire cable and pulley

1. Calibrate and verify the indication of the indicator matches the actual powder level.

2. Powder indicator's adjusting height: high limit is 500mm to the top of the pulverized coal bunker and the lower limit is 200mm to the bottom

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4.3.2 Coarse /fine pulverized-coal separator

4.3.2.1 Technical specifications of the coarse /fine pulverized-coal separator

TPRI-SZ series biaxial course Pulverized-coal Separator

(I) Equipment introduction:

TPRI-SZ series serial biaxial course Pulverized-coal Separator is one of the important equipments of the coal pulverizing system. It is used to separate the pulverized coal made by coal pulverizer. Main technical features of the TPRI-SZ series serial biaxial coarse Pulverized-coal Separator is: a stage of axial baffle is added between the inner and outer cones of the axial type coarse PulverizedⅡ -coal Separator against the shortcomings existing in the axial type and radial type coarse Pulverized-coal Separator pulverized coal. Air flow is made to rotate from the lower baffle extending the distance of rotation, enhancing the separation and improving the uniformity of pulverized coal; it is beneficial to the combustion of the pulverized coal in the furnace and to the improvement of the utilization rate of the pulverized coal so as to improve the economy effect of the boiler.

Its operating Principle is, pulverized coal air flow out of coal pulverizer enter the TPRI-SZ series serial biaxial coarse Pulverized-coal Separator from its lower part. It moves upwards. While the flowing section enlarges, the flow decreases. Therefore, part of coarse powder is separated by gravity. The remaining pulverized coal air flow enters the inner cone via deflector baffle. Rotating pulverized coal air flow is separated again by the centrifugal force; qualified pulverized coal air flow passes the bushing at the top and the fine pulverized-coal separator into the pulverized coal bunker; unqualified coarse pulverized coal returns to the coal pulverizer via air locker for further grinding.

(II) Equipment specifications:

Size: TPRI-SZ series serial biaxial coarse pulverized-coal separator

Type: Explosion proof & centrifugal

Quantity: 2

Deflector baffle: 32

Structure: shown below:

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Structure diagram of TPRI-SZ series serial biaxial coarse Pulverized-coal Separator

HL-GX series high efficiency fine pulverized-coal separator

(I) equipment introduction:

Fine pulverized-coal separator is equipment in the coal pulverizing system used to separate pulverized coal and air from the pulverized coal air flow coming from HL-GX series high efficiency fine pulverized-coal separator. Its operating principle is: pulverized coal air flow enter fine pulverized-coal separator along the tangential direction and rotate in the cylinder of the separator. Under the action of the centrifugal force, pulverized coal is thrown to the cylinder wall and drops down. Then it enter pulverized coal bunker through air locker, wood scraps separator. While air is induced out via center cylinder and sent to the furnace by mill exhauster.

( II) equipment specification:

Specification: HL-GX high efficiency fine pulverized-coal separator

Type: explosion prevention & centrifugal

Quantity: 2

Structure is shown below:

4.3.2.2 Coarse/fine separator maintenance


(I) Preparation 1. Before shutdown, check and record air leakage.

2. Prepare maintenance and lighting tool.

3. After work sheet is issued, open manhole

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and explosion door for natural ventilation.

4. Steel plate for repairing weld should be ready.

5. Before shutdown, empty the powder accumulation inside coal pulverizer.

(II) check internal abrasion

1. After verify the internal air is fresh and the safety measures are correct, for convenience of the check and repair activities, scaffold is to built up and be accepted.

2. Before enter TPRI-SZ series serial biaxial coarse Pulverized-coal Separator, test should be carried out on small animals.

3. Enter through manhole (or explosion door) to remove internal powder accumulation, check and record abrasion of the inner /outer cone, pipe and support of the inner cone. Parts with abrasion exceeding limit should be repaired or replaced.

4. When enter the separator, 12-24 V portable light should be used.

5. Before use the gas cutter or welder, lay asbestos cloth at the inlet of the separator to prevent sparks from entering the coal pulverizer.

1.

2.

3.1 It should be free of powder accumulation.

3.2 thickness of the inner/outer cone and pipe should be 2 mm; ≮

thickness of the support of the inner cone should be ≮3 mm.

3.3 internal parts of the separator should be intact.

(III) maintenance and adjusting of reflector baffle

1. Check abrasion of the baffle; repair or replace if the abrasion is over limit.

2. Calibrate baffle and adjust its turndown ratio.

1. Baffle thickness should be 2 mm.≮

2. Baffle should be agile; turndown ratio should be uniform.

(IV)seal up 1. After maintenance of separator, clean all internal debris.

2. Clean the joint surface and apply φ10 mm asbestos cord as packing; evenly tighten bolts.

2.1 bolts should be intact.

2.2 It should be tight.

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(V) maintenance powder return pipe

1. Estimate any abrasion based on operation; abrasion of the elbows should be checked once a year. Repair or replace parts with serious abrasion.

2. Check powder return pipe for any pulverized coal blockage, accumulation or leakage; correct if necessary.

3. Check outer insulation of the TPRI-SZ series serial biaxial coarse Pulverized-coal Separator.

4. After maintenance, air leakage test should be carried out.

1. Thickness of pipe wall should be 2 mm.≮

2. Powder return pipe should be free of blockage, accumulation and leakage.

3. Insulation should be complete.

4. It should be free of air leakage.

(I) Main maintenance tools: adjustable spanner, ladder, safety belt, gas mask, protective goggles, etc.

(II) Consumable and spare part spare parts:

Name Size Material Unit Quantity

1. Lower cone A3 Pcs 1

2. Reflector baffle A3 Pcs 32

3. Round steel Φ10 A3 M 15

4. Aluminum sheet 0.7MM A3 M2 6

5. Holding screw M16χ60 A3 M16 30

6.clamp nut M16 A3 M16 30

7.gasket Φ16 A3 Φ16 30

8. White paste paint Barrel ?<0} 0.5

9. Asbestos cord M 10

In addition, to prepare: steel plate, steel pipe, etc..

4.3.3 Maintenance of woodblock separator

Woodblock separator installation is located on the outlet pipe of coal pulverizer, which is used to separate the woodblock in the raw coal out of coal pulverizer. Its operating principle is that: when woodblock is carried out by the pulverized coal air flow from coal pulverizer, it will be stopped by the woodblock separator screen and absorbed to the screen. Pulling down the screen will cause the woodblock to fall down on the grating; then recover screen and open the rectangle hand hole to clean woodblock.

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Maintenance items, workmanship and quality standard of the woodblock separator


(I) preparation 1. Prepare maintenance tools and lighting facilities.

2. After work sheet is issued, open rectangle hand hole and maintenance door.

3. Clean woodblock and other debris from the grating and screen.

(II) check abrasion and action of the internal and external parts

1. Verify internal and external parts are intact; complete the missing parts.

2. Check abrasion of the screen; repair or replace if necessary.

3. Check abrasion of the casing and diaphragm; repair or replace them if necessary.

4. Take out grating, check its abrasion.

5. Check agileness of the screen and baffle. If seizing is found, remove bearing cap, clean padding inside bearing housing; add padding and recover it after adjust tightness.

1.

2. Thickness of the frame band iron of the screen should be 2 ≮

mm. Thickness of grating and grid bar should be 1 mm.≮

3. Casing thickness should be 2 mm. ≮

Thickness of diaphragm should be 1 mm.≮

4. Thickness of grating should be 1 mm.≮

5. Operation of screen and baffle should be agile.

(III) Close maintenance door

1.when activities above said are completed, close rectangle hand hole and maintenance door

2. Joint surface should apply with asbestos cord as padding; all bolts should be evenly tightened.

2.1 should be free of air leakage.

2.2 bolts should be intact.

4.3.4 Maintenance of wood scraps separator

Wood scraps separator is located after fine pulverized-coal separator and air locker, which is used to separate wood fibre from the pulverized coal.

Pulverized coal enter wood scraps separator from its lower part. Pulverized coal enters the pulverized coal bunker after wood fibre is separated. Turn the screen turntable 180° and open hand hole. Then wood scraps remained on the screen can be cleaned. This process will not

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affect the normal operation of the wood scraps separator.

Maintenance item, Workmanship and Quality standard for wood scraps separator

Maintenance item


(I) Preparation prior to maintenance

1. Prepare maintenance tool and lighting facilities.

2. Before work sheet is issued, no maintenance is permitted.

(II) Screen maintenance

1. Open right cover plate. Take out four screens and clean wood scraps and other debris.

2. Check sieve for any rupture and repair or replace if necessary.

1. Screen mesh 上

should be free of wood scraps and other debris blockage. 2. Sieve mesh should be intact.

(III) Maintenance of turntable

1. Remove hand wheel and bearing gland bush; add diesel before rotate shaft to make it move agilely.

2. Recover bearing gland bush and hand wheel

1. Turn around hand wheel and the rotation should be agile.

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(before recover check felt sealing and gasket, replace unqualified materials).

2. Tightness of the gland bush should be suitable.

(IV) recover cover plate

1. Locate four screens. Recover right cover plate and lay down felt before tighten bolts.

1. Bolts on cover plate should be intact and free of powder leakage.

4.3.5 Air locker maintenance

Air locker used in this project contains two types: cap type and flip/flop type. Cap type air locker is used on straight pipes, which is composed of casing, conical cap shaft and heavy hammer. Flip/flop type air locker is installed on the declining pipes. When turning plate is closed, it should form a angle of 60 degree with the fuel flow direction. It is composed of casing, turning plate, shaft and heavy hammer. Air locker is used to prevent air entering the system when pulverized coal passes air lock to pulverized coal bunker (or when coarse powder drops into coal pulverizer). Air lockers in system are in series with two units. When one unit is open, the other is in close state.

Maintenance items, workmanship and quality standard of the air locker

Maintenance item


(I) Preparation Prepare tools and lighting facilities.

(II) Check abrasion of internal parts

1. Remove upper and lower joint flange of the air locker.

2. Check abrasion of the internal parts; repair or replace parts seriously worn.

2.1 Abrasion of the valve (or ball valve) should not exceed 1/3 of the former thickness.

2.2 Thickness of the air locker casing should be

2 mm.≮

(III) Check tightness and agileness

1. Check tightness of valve (or ball valve).

2. Adjust the moving part of the air locker to agile.

1. Valve (or ball valve) should be closed tightly.

2. Air locker should operate agilely without blockage.

(IV) Adjust balancing hammer

Adjust balancing hammer as per requirements.

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(V) Recover 1. Check bolts of parts.

2. Install air locker into the former system (seal the joint surface with qualified asbestos yarn), and tighten bolts.

1. Bolts should be intact.

2. Air locker should be tight without leakage.

4.3.6 Coal gate maintenance

Coal gate is located at the lower coal hopper which is used to isolate raw coal. Its operating Principle is to open of close the coal path by inserted parallel pipe and it is easy for the maintenance of coal feeder.

Coal gate Maintenance item, Workmanship and Quality standard

Maintenance item


(I) check abrasion of channel steel frame

1. When raw coal bin is empty, check abrasion of the channel steel; repair or replace part if abrasion limit is exceeded.

1. Average thickness of the frame should not be less than 1/3 of its former thickness.

( II) Check abrasion and operation of spile

1. Check abrasion of the spile and its operation. Worn spile should be replaced; spiles with visible bending should be calibrated.

1. Spile should be free of wornout and visible bending. Its operation (in and out) should be agile.

4.3.7 Explosion door maintenance

Explosion door is a device used to protect system and equipment. Explosion doors in coal pulverizing system are normally installed at the outlet of coal pulverizer, outlet of pulverized-coal exhauster and on the equipment of TPRI-SZ series serial biaxial coarse Pulverized-coal Separator and pulverized coal bunker. Its operating Principle is that: when explosion occurs in some part of the system, explosion door will burst at first to rapidly release the pressure caused by explosion so as to protect the system and equipment from damage.

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Maintenance items, workmanship and quality standard of explosion door

Maintenance item

Workmanship and precautions n Quality standard

(I) Preparation

1. Decide whether to build scaffold according to the position of the explosion door; scaffold should be checked by relative party before application.

2. Prepare necessary tools and spare parts.

(II) Check explosion door

1. Check explosion door for any rusting wornout or leakage. Replace iron sheet of the explosion door not satisfy requirements. When replace, apply new qualified packing seal and tighten bolts evenly.

1.1 Diaphragm plate explosion doors should be free of rupture. Diaphragm plate must be made by 0.5 mm galvanized sheet iron.

1.2 Explosion door flange bolts should be intact and its joint surface should be tight.

4.4 Maintenance of Pulverized Fuel Feeder

4.4.1 Technical specifications of pulverized fuel feeder

(I) Equipment introduction:

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1 General

SGF series pulverized fuel feeder is fabricated by Shenyang Huadian Power Engineering Company Limited based on absorbing advantages of all kinds of pulverized fuel feeders. It is the latest developed product against current application conditions and problems of Chinese pulverized fuel feeder. This equipment is characterized by its advanced principle, complete function, compact structure and accurate output adjustment. It is suitable for pulverized coal with fineness of R90=12%, moisture content (dry basis) of ≤1.3% and medium temperature of ≤ 120 . This device has high reliability and maintainability, which is highly regarded by clients.℃

1.1 Type description

SGF -XX

Capacity ××tones/ hours

Code for coal feeder

1.2 Operating Principle

SGF type pulverized fuel feeder is an advanced powder feeding equipment. Pulverized coal flows to the baffle plate on the upper of pulverized fuel feeder and gullet of impeller through coal bunker. Rotating impeller brings the pulverized coal to the powder falling outlet at the bottom of impeller casing. Pulverized coal drops to the discharge impeller. After 90° turn, the impeller transports the pulverized coal to powder discharge pipe via powder falling outlet. The whole process is continuous, even and automatic. Powder flow is adjusted by changing the speed of impeller.

1.3 Features of equipment structure and performance

The entire unit is composed of upper part, lower part and reducer.

Upper part assembly:

Upper part assembly adopts flashboard structure maximizing the space for coal feeding; it eliminates the potential of pulverized coal bulking; thickness of the sealing layer is increased to ensure the reliability and tightness of the sealing of the flashboard plate sealing. Stainless steel flashboard plate has stronger capacity against environmental corrosion and other pulverized coal corrosion.

Lower part assembly

Lower part assembly is the main part of the pulverized fuel feeder. Main shaft, scraper and impeller form the conveying part for pulverized coal inside the lower part. Its structure can

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sufficiently ensure the operator to accurately control the output of the pulverized fuel feeder and prevent pulverized coal from flowing automatically.

Reducer assembly

Reducer is composed of a stage of worm assembly. Flange of the reducer is connected to the lower part of feeder via reducer seat. Reducer output shaft connecte with the main shaft via a cross sliding block coupling. Reducer structure is compact easy for maintenance. And reliable sealing ensure reducer free of seepage.

(II) Equipment specifications:

Type: series pulverized fuel feeder

Structure is shown below:

1.Flashboard 2.Upper part 3.Handwheel 4.Feeding impeller casing 5.Feeding impeller

6.Drive pin 7.Measurement impeller 8.Butter cup 9.Vent cock 10.Worm gear casing

11.Worm 12.Main shaft 13.Conical roller bearing 14.Worm wheel 15.Powder outlet pipe

16.Cap of the reducer 17.Lower part 18.Gland bush 19.Sealing unit 20.Clapboard

21.Scraper 22.Middle sleeve

4.4.2 Maintenance of impeller pulverized fuel feeder


(I) check before 1. Check current value, vibration 1. Current value should be ≤5

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maintenance value and bearing temperature of the pulverized fuel feeder under rated load,.

2. Review the defect record of the equipment. 3. Check pulverized fuel feeder for any oil leakage or powder leakage.

4. Check pulverized fuel feeder inside for any abnormal sound.

5. Verify the joint bolts of the pulverized fuel feeder are intact and tightened.

ampere; vibration value should be ≤0.1 mm; bearing temperature should be ≤70 .℃

2. Defects should be accurately and completely reviewed.

3. Should be free of leakage.

4. Should be free of abnormal sound.

5. Bolts should be intact and well tightened.

(II) disassemble pulverized coal chute, motor and pulverized fuel feeder

1. Verify pulverized coal bunker is free of pulverized coal inside.

2. Close left and right flashboard plates of the pulverized fuel feeder; empty pulverized coal in the coal feeder before shutdown.

3. Cut off power supply and disconnect circuit breaker; carry out a switching to verify the power supply has been cut off before maintenance.

4. Remove pulverized coal chute flange bolt, and take off pulverized coal chute.

5. Apply temporary end enclosure at the primary air pipe inlet to prevent debris.

6. Remove accumulated coal in the pulverized fuel feeder.

7. Remove oil drain hole bolts, and completely drain out lube oil inside the pulverized fuel feeder. Oil should be stored with special bucket to avoid fire.

8. Remove coupling cage and

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coupling connecting screw to dismount the motor.

9. Dismount pulverized fuel feeder, and clean internal pulverized coal.

(III)Dismantling of scraper and upper/lower impellers

1. Disassemble top bolts, spring gasket and spur guard to take off scraper.

2. Remove diaphragm sunk screw to take off lining plate and upper feeding impeller; remove middle lining plate to take out drive pin and lower measure impeller; disassemble middle sleeve on the main shaft.

3. Before disassembling activities, match marking should be made; removed parts should be numbered.

4.. Recover parts as the reverse order of dismantling; measure and adjust the following items:

(1) Measure scraper tortuosity, radial clearance and clearance between scraper and upper lining plate filler gauge.

(2) Measure radial clearance and upper / lower clearances of the upper/lower impeller and casing with filler gauge.

(3) Measure clearance between main shaft and middle sleeve with slide caliper and inside calipers.

1. Scraper should be free of crackle and damage and its bottom should be flat.

2.impeller,lining plate and sleeve should be intact.

3.

4.1.1 scraper radial clearance should be 1.5~5 mm.

4.1.2 Clearance between scraper and upper lining plate should be 1.2~1.4 mm.

4.1.3scraper tortuosity should be 0.5 mm.≯

4.1.4 Spur guard and top bolts should be complete and secured with spring gasket.

4.1.5manually turning of scraper should be agile.

4.2.1 Radial clearance of upper /lower impellers and casing should be 0.5±0.15 mm.

4.2.2 Upper clearance should be 1.2~2 mm.

4.2.3lower clearance should be 1-1.5 mm.

4.3 it should be 0.05~0.10 mm; replace it when clearance > 0.20 mm.

(IV) dismantling worm wheel reducer

1. Remove middle connecting screw of the pulverized fuel feeder; lift the worm wheel

3.1 Main shaft appearances should be free of crackle, drawing stamp

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casing reducer casing and powder exhaust pipe to a position laid with woodblock. Before disassembling, make match marking on relative parts.

2. Disassemble gland bush of the worm wheel reducer casing upper cover, main shaft and middle sleeve.

3. Wash, check and measure main shaft.

4. Remove oil deflector ring, worm, worm wheel, coupling and bearing; wash and check them.

5. Recover worm and worm wheel; adjust clearances between parts; install coupling on the worm shaft. Coat the shaft within oil before assembling and install oil deflector ring.

Sealing of felt at the joint of the main shaft and worm wheel reducer casing upper cover should be good. End cover joint surface should be coated with shell-lac and replace a new padding.

Fill new lube oil.

and burr.

3.2 Tortuosity and ellipticity of the main shaft should be 0.5 and ≯

0.05 mm respectively.≯

4.1 Bearing surface should be smooth free of pocking mark, crackle and other defects.

4.2 Clearance of bearing balls should be 0.1 mm.≯

4.3 Worm bending should be 0.15 mm.≯

4.4 Steel bushing of the main shaft bearing and bearing inner hole of the worm wheel should be homocentric; and nonperpendicularity of the working impeller surface should be

0.04/100.≯

4.5 Abrasion of the worm and worm wheel tooth surface should be

1/2 of the former thickness.≯

5.1 Contact area of the engagement of the worm wheel and worm should be ≥ 60%.

5.2 When modulus is 5, root of tooth clearance during engagement of worm wheel and worm should be 1.25-1.50 mm.

5.3 Swaying clearance of the worm should be 0.2≯ -0.25 mm.

5.4 Indication of oil level and clear.

5.5 Reducer casing should be free of oil leakage.

(V) dismantling of upper part

1. Remove upper part from the pulverized fuel feeder; dismantle and wash maintenance drive screw mandrel and nut.

1.1thread abrasion should not exceed 1/2 of former thickness.

1.2 swaying of screw mandrel

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2. Check and repair powder falling flashboard and manhole.

3. Reinstall upper part onto the lower part; replace gasket and tighten bolts.

should be 0.02 mm.≯

1.3 screw mandrel bending should be 1 mm.≯

1.4 moving of screw mandrel should be agile.

2.1 powder falling flashboard and manhole should be tight without leakage.

2.2 turndown ratio indication of the powder falling flashboard should be correct.

3. Joint surface between upper part and lower part should be tight without leakage.

(VI) recover coal exhaust pipe

1. Replace padding, recover coal exhaust pipe and tighten bolts.

1. It should be tight.

(VII) motor installation

1. Install coupling onto the motor shaft; lift it up to pulverized fuel feeder body; align axial and radial clearance of motor coupling and worm coupling.

1. Both axial and radial clearance should be 0.05 mm. ≯

(VIII)pulverized fuel feeder test run

1. Check lube oil filling of parts.

2. Check tightening of the connecting screws.

3. Close coal falling baffle.

4. Manually rotate coupling to check its operation.

5. Protection device should be kept intact and reliable.

6. During test run, increase rotate speed gradually and record the no-load operation of the pulverized fuel feeder under different rotate speeds. Time of test run is 4 hours.

1. Oil quality is acceptable and oil level is correct.

2. Joint bolt should be secure and reliable.

3. It should be free of seizing and abnormal sound.

4. It should be free of oil leakage, powder leakage.

5. current, vibrations, bearing temperature should be in the specified range.

Maintenance main tools and spare parts of impeller pulverized fuel feeder

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(I) Main maintenance tools:

Wrench, hoist, tommy bar, hand hammer, copper bar, screw driver, wire cable, scraper, abrasive paper, filler gauge and gear puller.

(II) Spare parts

Common faults and trouble shooting for impeller pulverized fuel feeder

Faults Cause Treatment

(I) large current

1. Clearance between main shaft and middle sleeve is too large and sealing is poor; pulverized coal enters sleeve; lubrication is bad.

2. Clearances of sealing positions exceed limit; pulverized coal enters reducer casing, lube oil deteriorates; friction of the worm wheel and worm increases.

3. Clearance between impeller and diaphragm is too small causing abrasion.

4. Impeller surface is not vertical to shaft causing abrasion.

5. Worm is free of swaying clearance or too low clearance.

6. No axial play clearance between two couplings.

1.1 wash and replace gland packing as well as improve lubrication.

1.2 repair or replace middle sleeve.

2. Improve sealing.

3. Replace gasket and adjust swaying clearance.

4. Redisassemble it and adjust verticality; replace damaged parts.

5. Adjust the clearance with gasket until a proper value.

6. Adjust the clearance to a suitable range.

(II) oil leakage

1. Sealing is invalid or synthetic glass of the oil level gauge is damaged.

1. Replace sealing or oil level gauge synthetic glass.

(III) motor vibration

1. Coupling center disposition.

2. Motor set screw loose.

1. Align center again.

2. Tighten set screw.

(IV) oil quality deterioration

1. Quality of former lube oil is unacceptable or pulverized coal enters oil.

1. Replace new oil; eliminate powder leakage and replace oil seal.

(V)pin of scraper breaks

1. Strength decreases because of abrasion.

2. Woodblock, iron block or other foreign matters block to cause overload.

1. Replace pin.

2. Remove debris.

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4.5 Pulverized Coal Conveyer Maintenance

4.5.1 Pulverized coal conveyer technical specifications

(I) Equipment introduction

Conveyor is transporting equipment mainly used to evenly distribute pulverized coal from fine pulverized-coal separator to individual pulverized coal bunkers.

Type: LSG-500 transmission distance: 32.2m. Capacity: 100t/h; motor power: 2×7.5KW

General installation of equipment

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Sectional view of the box

4.5.2 Maintenance items of the pulverized coal conveyer


(I) preparation

1. Prepare maintenance tools and lighting tools.

2. Issue work sheet thermodynamic maintenance and verify all safety provisions have been ready before maintenance.

3. Empty pulverized coal inside packing auger before start maintenance.

(II) reducermaintenance

1. Disassemble coupling and reducer as well as bottom plate joint bolt. Lift reducer with hoist on the maintenance support.

2. When disassemble parts, match marking should be well made.

3. Disassemble small end cover and frame joint bolt, open casing cover.

4. Disassemble frame and gear roller joint bolt, remove frame .

5. Turn four screws into the screw hole of the load balancing ring. Evenly separate load balancing ring from the pin roll; then take out pin roll bush.

6. Lift out pin wheel housing and knock the tooth

1. Frame should be intact free of crackle and oil leakage. 2. Pin roll and pin bush should be free of bending deformation; abrasion should be 0.05mm.≯ 3. Eccentric shaft eccentricity should be 2±0.02 mm; bearing should be tightened.

4. Keyway abrasion should be 1mm, inner outer ring ≯

of bearing and rolling parts should be free of crackle, corrosion; rotation should be

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pin with copper bar to remove gear roller.

7. Take out upper cycloidal gear diaphragm and lower cycloidal gear.

8. Take out eccentric shaft assembly.

9. Disassemble input shaft positioning bolt, take out large end cover and oil seal.

10. Wash all parts.

11. Check frame, input shaft, output shaft, pin roll, pin bush and eccentric shaft abrasion.

12. Check bearings’ appearance and measure clearance.

13. Check abrasion of cycloidal gear and cam.

14. Check abrasion of the pin wheel housing, gear pin and gear roller.

15. Based on match marking recover reducer and fill in qualified lube oil.

agile; bearing clearance should be 0.15mm.≯

5. Cycloidal gear and cam should be free of crackle, abrasion should be

0.1mm.≯

6. Pin wheel housing should be intact without crackle or oil leakage. Gear pin, gear roller should be free of bending deformation, abrasion should be 0.1mm.

7. Oil seal should be properly installed. 8. Rotation should be agile without seizing. 9. During test run, vibration should not exceed limit and free of oil leakage and other abnormal situation.

(III) chain wheel maintenance

1. Check parts of chain wheel, any crackle should be repaired immediately.

2. Check inspection doors, supporting roller, fairlead wheel, scraper plate and inlet, outlet flashboard. Replace the part with defects unable to be repaired. Verify the wire cable is intact.

3. Check joint surface bolts.

1. Chain wheel should be intact, and parts should be free of crackle.

1.1 check doors should be intact, and sealing is acceptable.

1.2 Supporting roller, gear blocks, fairlead wheel, scraper rod fixture block should be intact without deformation, rupture and digression.

1.3 When the abrasion of inlet/ outlet flashboard is greater than 1/2 of former thickness, replace the part. Sealing should be tight with a clearance 0.20mm. ≯

Otherwise add gland

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packing.

1.4 wire cables are free of breaking; joint should be secure.

2.1 bolts of parts should be intact without damage.

(IV) installation of flight chain

1. Flight chain is the key part of the embedded scraper transporter. Before installation, verify joints of flight chain are agile. Remove if necessary. Grind pin roll and chain bar hole with abrasive paper. Do not coat lube oil or grease.

2. Before installed in flight chain, head and tail cover plates should be checked and sight cap be open. Move the tail shaft to the foremost front of the head direction to determine the direction of the flight chain (refer to Fig3) and prepare flight chains needed and the others are to be used as spare parts.

Great wheel teeth drive the large head of the chain bar of the flight chain; and direction should be proper. The following figure shows the engagement of the great wheel teeth and flight chain when great wheel runs

�as per direction shown in the figure.

Flight chain installation diagram

Chinese English

钢丝绳 Cable wire

头部 Head

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过渡段 Changeover portion

中间段 Middle section

3. Before installation of head part, prepare two wire cables which is 3-4m longer than the length of machine body. Then install transition section. Pull out upper and lower cable wire towards tail direction. Install middle section, and tail section orderly. After installation of the main equipment, the upper and lower wires should have been pulled to the tail part.

4. Firstly install lower flight chain; tight the first group of flight chain ( ten sections as on group) with cable wire at the tail part; pull the lower cable wire to pull in the first group of scraper and then connect it with another group. Keep drawing the lower wire until the lower wire is pulled out from the head section.

5. Then install upper flight chain in the same way of installation of lower flight chain. However, their direction is opposite. If the head rotates counterclockwise, the small head of flight chain will move towards the head direction and the large while that of the upper flight chain is opposite.

6. Connection of the flight chain. First connect the upper and lower flight chains at the head section. Then pull the upper or lower flight chain at the tail section. Tension flight chain to define a suitable length and then connect the flight chain at the tail part. Installation of main machine and flight chain complete.

运行方向 Running direction

大头 Large head

7. Precautions

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A. Installation of the flight chain must be correct with the same direction as great wheel.

B. Clamp the elastic collar or weld the pin roll retaining rings when connects �the flight chains. Otherwise, during flight chain operation, pin roll may loose

or cause serious accident.

(V) installation of drive device

1. Motor reducer and drive mechanism should be securely welded on the foundation platform or head of the main machine. Details please refer to [Technical Agreement] and [Contract]. During installation, the output shaft of the reducer should be parallel with that of great wheel. During open chain driving, the centerlines of the great and small chain wheels should be on the same straight line. The following check method could be adopted. After adjustment of the drive device, weld it with the foundation securely or secure it with bolts to ensure stable operation of the equipment.

Check method of drive device installation quality

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(VI)preparation before test run

1. After installation of parts, carry out no-load test. The following procedures should be done for no-load test preparation:

1.1 all bearing driving chains and reducer should contain sufficient lube oil and grease.

1.2 check machine groove for any left tool and material; remove if any.

1.3 primarily check tightness of chain by the following ways:

First throw the coupling between motor and reducer or pull straight the chain below motor fan blade, and then check the loosing position of the great wheel ( shown in the Figure)

�Check method for chain jamming tension

(V) test run

1. Motor test runs without load test and verify the rotation direction; tighten coupling bolts and recover casing before 1 hour no-load test run; check for any abnormal situation.

2. On-load test run for 1 hour.

1.1. It should be free of oil leakage, powder leakage; there should be no abnormal sound from individual parts.2.2. Current, vibration and bearing temperature should be in the specified range (I≤17A, vibration 0.10mm, ≯

bearing temperature 40 ).≯ ℃

4.5.3 Pulverized coal conveyer trouble shooting

Faults Cause Treatment

Flight chain run out 1. Installation of the conveyer is not good

1. Check installation quality

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(1) straightness of whole machine is over limit

(2)head and tail block are not centered

(3) wheel axle deflexion

2. Casing may deform 2. Calibrate casing

3.tailblock adjusting strokes are not uniform; tail block deflexion

3. Adjust evenly

1. Hard objects in the machine groove block the chain

1. Remove debris

2. Chain abrasion is serious 2. Replace chain

3. Full load startup or sudden load increasing

3.feed materials evenly after manually material discharge

Flight chain is broken

4. Collar on the chain falls down to loose pin roll out

4. Spot welding of collar

1. Casing is not straight; flange and lead rail are dispositional

1. Readjust

2, hard objects in the machine groove 2. Remove debris

3. Scraper and chain bar are not well welded.

3. Replace chain link

Deformation or rupture of scraper

4. Engagement of the flight chain and great wheel is not good.

4. Check adjust

1. Hard objects or iron parts in the machine groove

1. Remove debris Flight chain impulse with sound during operation

2. Rotation of a certain chain link is not agile

2.remove pin roll to repair

1.great wheel shaft deflexion 1. Calibrate and adjust the shaft level

2.great wheel is uncentered 2. Calibrate great wheel

Engagement of the great wheel and flight chain is not good

3. Chain space increases after long term operation

3. Replace chain

Floating chain 1. Chain tensionness is not enough 1. Adjust tensioning device

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2. Material form a pressed layer on the casing bottom plate

2. Clean and add pressing rail if necessary

4.5.4 Operation and repair

1. After each startup, run without load for awhile until equipment operates normally before feed materials. Feeding should be kept evenly without sudden change or overload.

2. Unless specified, equipment should not be shutdown with load. Normally, equipment should not be shutdown until materials in the machine groove are discharged. For the startup after emergency shutdown because of full load transportation, Jog the equipment for several times or manually remove the material in the machine groove.

3. If several conveyors form a streamline, the last one should be started up at first while the shutdown procedure is opposite. The startup also can be control by interlocking

4. Operator should regularly check parts of the machine. Especially the flight chain and drive device should be kept intact. Immediately repair or replace the damaged parts (such as deformation of scraper, falling off of the cotter pin, serious abrasion of the bending section of the lead rail).

5. During operation, prevent iron part, large hard objects or debris from entering conveyor to avoid equipment damage or accident.

6. Keep good lubrication of all bearings and drive parts. Lubrication of embedded scraper transporter is shown in the following figure. Attention should be paid not to apply grease on the flight chain, support lead rail and great wheel, tail block.

7. Normally a minor overhaul every 6 months, a medium overhaul every year and an overhaul every 3 years should be carried out for the embedded scraper transporter. During overhaul, all parts of the embedded scraper transporter should be removed and cleaned; replace abrasion parts. Motor, reducer should be maintained or repaired as per their relative technical requirements.

8. For conveyor operating seasonally, maintain and care it during outage. A little #10 lube oil can be dropped between flight chain pin roll and chain bar to avoid seizing caused by corrosion; food oil can be used in case of foodstuffs delivery.

Lubrication part Lubrication material Lubrication interval

Lubrication method

Turning bearing 1#lithium base grease 500 hours Oil gun or coat

Lead rail of tensioning device

1#lithium base grease 800 hours Coat

Adjusting screw of tensioning device

1#lithium base grease 800 hours Coat

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Exposed driving chain Exposed gear oil(220#)

1.5 months Coat

Gear reducer N320 gear oil Every 3 months after 1 month

Fill

Motor 1#lithium base grease 3 months Coat

Appendix 2 main wearing parts breakdown table

5 Tailblock Aperture D=ф110

4 Great wheel Aperture D=ф160 Tooth number Z=9

3 Outlet flange

2 Pin roll

1 Flight chain Include pin roll and collar, etc.

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Serial No. Name Drawing No. Remarks

4.6 Jet Lubrication Unit Maintenance

4.6.1 Jet Lubrication Unit Technical Specifications

(I) Equipment Introduction:

Coal pulverizer jet lubrication unit is the lubrication equipment for coal pulverizer large gear tooth surface, mainly composed of oil system, air system, control system and sprinkler plate; its operating Principle is to atomize the high viscosity lube oil by compressed air via a specially designed jet valve and jet the oil onto gear working face. Form and maintain a layer of oil film on the surface of the gear engagement to realize liquid friction.

Fig. 5-6-1 Diagram of coal pulverizer jet lubrication system

Chinese English

油系统 Oil system

气系统 Air system

喷射板 Sprinkler plate

大齿轮 Large gear

小齿轮 Small gear

齿轮罩 Gear cover

(II) Main technical parameters:

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Working medium: industry gear lube oil N460;

System oil pressure: 0.05-1.2MP

System air pressure: 0.05-0.7MP

Lubrication width: 270-800mm

Jet distance: 200+10mm

Oil supply capacity: 3.15L/min

Volume: ≥120L

Main circuit parameter: 380 V 1.5A

Air pump parameter: 220V 9A (4.5A)

Control circuit parameter: 220V +5% 50Hz

Dimension: 1000×500×1600mm (double-machine: 1730mm)

4.6.2 Jet Lubrication Unit Maintenance


(I) maintenance of oil line system of coal pulverizer jet lubrication unit

1. Pump out residual oil inside oil tan.

2. Disassemble oil pipe and open oil tank upper cover.

3. Remove joint bolt of the oil pump and remove entire oil pump to check.

4. Clean debris dirt inside oil tank and oil pipe, and blow oil tank, check oil pipe and joint for any blockage and seepage .

3.1. Check from the appearance of pump body, coupling should be free of defect.

3.2. Pump should be free of abnormal sound during operation; gear engagement should be stable; joint flange of end cover and casing should be tight.

4. Oil tank, oil pipe should be free of debris, dirt, oil pipe and joint should be free of blockage and oil leakage.

(II) coal pulverizer jet lubrication unit air system maintenance

1. Vent residual air in the air compressor; remove air compressor air pipeline and check relative valves.

2. Remove complete air compressor from the housing;

1. Air pipeline, air compressor head gasket and pressure regulating valve, check valve should be intact without air leakage.

2. Air compressor should be free of

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check air compressor and air compressor proper.

oil leakage and air leakage with proper pressure.

(III) maintenance of sprinkler plate oil injection nozzle of the coal pulverizer jet lubrication unit

1, disassemble oil pipe and air pipeline connecting sprinkler plate 2, dismount oil injection nozzle from sprinkler plate,3, check and clean sprinkler plate, oil injection nozzle and pipeline.

1. Sprinkler plate should be intact; oil injection nozzle and pipeline should be intact without blockage.

4.7 Maintenance of primary air pipe

Maintenance item


(I) check inside of primary air pipe

1. Open a hole of 300mm at the elbow of primary air pipe to check abrasion of air duct.

2 check primary air pipe inside for any powder accumulation.

1. Inside should be free of obvious abrasion; abrasion of hexsteel should not exceed 2/3 of the former thickness.

2. Verify air duct inside is free of powder accumulation.

Hot air system

Maintenance item


(I) Check isolating valve

1. Open bearing housing of the hot air valve, take out gland bush, and check packing set.

2. Check connection of the isolating valve flashboard and cylinder shaft for any sealing off and bolt loosing.

3. Check agileness of the flashboard.

1. Packing set is intact, without damage or ash leakage.

2. Bolt is free of loose and sealing off.

3. It closes and opens agilely without seizing.

(II) Adjusting valve

1. Open bearing housing of the adjusting valve and take out gland bush to check packing set.

2. Check connection of the isolating valve flashboard and cylinder shaft for any sealingoff or bolt loosing.

3. Check agileness of the flashboard.

1. Packing set should be intact without are leakage.

2. Bolt is free of loose and sealingoff.

3. It closes and opens agilely without seizing.

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(III) hot air pipe 1. Check hot air pipe for any ash leakage.

1. Sealing is tight without air leakage or ash leakage.

4.8 Maintenance of Bag-type Dust Collector

Maintenance item


1. Cut off the motor power supply of lower spiral conveyor of the dust catcher.

Before maintenance, make sure motor power is shut down.


2. Close outlet cinder valve of the dust catcher.

1. Open upper cover plate of collector.

2. Check primary port. Primary port is clean without blockage.

3. Clean the bags inside the bag-type dust collector.

Bag is clean inside, pressure deference is normal during test run.

(II) Maintenance of the upper and lower box

4. Check the frame. Thickness of the internal frame should not be less than 1/3 of the former thickness.

(III) maintenance of ash handling system

1. Check mesh of blowpipe for any blockage.

Mesh of the blowpipe should be free of blockage.

(IV) maintenance of spiral pulverized coal conveyer

Refer to the spiral pulverized coal conveyer at the lower part of the powder separator

1. Maintenance of the reducer refer to that of the above said cycloidal-pin wheel reducer

2. Maintenance of separation gear. Thickness of the separation gear should not be less than 1/3 of the former thickness.

(V) maintenance of cinder valve (Variable frequency feeder)

3. Pipe abrasion. Thickness of pipe wall should not be less than 1/3 of the former thickness.

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5 Primary air fan (mill fan), force draft fan , induced draft fan

5.1 Primary air fan (mill fan)

5.1.1 Technical specifications of primary air fan

Denomination of fan type and design parameter

Fan type: 1788AB/940

It means:

178= impellerIDbladeOD

Blade OD: diameter of blade outlet;

Diameter ID: diameter of impeller inlet

8-- Serial number of aerodynamic model

A-- Axial cutting of impeller

B—Double base

Diameter of impleer inlet (mm)

Technical specifications

TB BMCR

Medium: air air

Density: 112 kg/ m3 1.168 kg/ m3

Flow rate: 33.99 m3/s 25.89 m3/s

Total pressure:14850 Pa 11000 Pa

Inlet temperature:39 ℃ 24 ℃

Rotate speed:1480r/min 1480r/min

Shaft power:347.3KW 259KW

Motor power:400KW

Angle: inlet: 90o outlet :0o(seen from the motor side)

Manufacturer: Shanghai Blower Works

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SFY15F-C5A General Assembly Drawing of Primary Air Fan

5.1.2 Maintenance of primary air fan


(1) Coupling maintenance

1.Remove the coupling guard and the joint bolt, clean up the removed parts and keep them in order; marks used for reassembly and alignment shall be well established.

2. Check the clearance among each part of the coupling and record properly.

3. Check whether such defects as cracks and deformation exist in the coupling.

4. Check whether the joint bolt is in good condition. Whether bending deflection exists in the bolt, non-conformity bolts shall be replaced.

Check whether the diaphragm is of intactness, and exists no permanent deformation and

1. The coupling shall be of intactness and keep surface finish; with no cracks and deformation; the coupling and the shaft shall be securely engaged and without loose fits.

2.There shall exist no bending deformation in the joint bolt, the screw thread shall be in good condition; wahser, spring pad and nut shall be furnished well.

3. The diaphragm and the

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cracks.

6. Assembly:

(1) After the center getting aligned, assembly the coupling and clean up the coupling, pipe nipple, diaphragm and joint bolt, etc.

(2) Align the pipe nipple with the original marks of the coupling

(3) Refit the coupling guard.

Note: Contact shall be avoided between the coupling guard and the ratating parts.

joint bolt shall be fitted tightly and the clearance shall not be over 0.30mm.

4. Lopsided wears of the coupling and pipe nipple are not more than 0.5mm.

5. Parts with a wear value of more than 0.5mm shall be replaced.

(2) Maintenance of impeller and current collector

1. Remove the housing and the bolts in the gas inlet casing, and keep them properly.

2. Open the manhole door for apprasial prior to maintenance and make records. Assembling condition of the impeller shall be checked before removing the impeller. 3. Check whether huge deformation and cracks exist in the blade and the impeller disk. 4. Repair welding shall be performed if cracks and wear occur to the weld joint between the impeller and the impeller disk.Cracks shall be cleaned up prior to performing repair welding.

5. Check whether the rivet and the bolt that connect wheel hub and impeller disk get loosen or worn.

6. Check the fit between wheel hub and the main shaft to be free from loosen.

7. Check the current collector to be free from deformation, correction shall be performed if a set value is exceeded.

8. Check whether rub contact traces exist in the dynamic and static parts.

1. The blade and impeller disk shall be free from cracks and deformation, and the wear value of the blade shall less than the 1/3 of the original thickness.2. The joint bolt and rivet that connect the wheel hub and the impeller disk shall be free from loosen.

3. The fit between wheel hub and the main shaft shall be free from loosen, and the tension force is generally set at 0-0.02mm

4. Cracking phenomena of the current collector shall be refrained.

5. Refer to figure 5-1 for the fit clearance between the current collector and the impeller.

(3) Check of the inlet muffler

1. Check carefully from the inlet and outlet sides of the muffler whether the mesh enclosure of the muffler insulation plate is corroded, whether the screw and mesh

1. Muffler insulation plate shall be flat and level, and be free from detachness,

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enclosure is detached or get tilted. If the mesh enclosure is found corroded, tilted or detached, repairation measures shall be taken immediately.

2. Check whether the acoustic material in the muffler insulation plate is exposured or leaked.To prevent the acoustic material from blocking the air passage and thus impairing the power of the fan, treatment measures shall be taken immediately if exposure and leakage are found to be existed.

tilt and corrosion.

2. Acoustic material shall be in good condition and free from exposure.

4) Maintenance of the main shaft

l. Check whether the main shaft is cracked, corroded and worn.

2. Check the main shaft to be free from bending.

3. Check the roundness size of the main shaft journal and whether galling phenomenon exists.

4. Check whether the protective sleeve of the main shaft is in good condition.

1. The main shaft is free from cracks, corrosion and wear.

2. The bending percentage of the main shaft shall not be more than 0.05mm/m and no bigger than 0.10mm/m over the full length.

3. The deviation of the roundness size of the main shaft journal shall not be more than 0.02mm.4. The protective sleeve of the main shaft shall be in good condition; the clearance between the main shaft and the protective sleeve shall be 0.06~0.08mm.

5) Maintenance of bearing box and bearing

1.Check whether the lube oil is deteriorated or contaminated by sampling tests. When the quality of the lube oil is unqualified, it shall be changed.

2. Check the bolts in the upper and end covers, the screw shall be free from cracks and bending; the thread shall be intact and fittings be complete; the removed bolts shall

1. The internal and external sleeves of the rolling bearing and the ball bearing shall be free from such defects as cracks, obvious spots and corrode pittings.

2. The clearance between the bearing and the shaft

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be cleaned up and kept in order.

3. Measure the fit clearance among each part of the bearing box and complete the records.

4. Clean up the bearing box; check the internal and external sleeves, spacing ring and ball bearing.

5. Measure the bearing clearance and spacing ring clearance, and unqualified ones shall be replaced.

6. Check and clean oil level gauge, oil level gauge calibration shall be practiced if necessary, the highest oil level is rarely higher than the center line of the downmost ball bearing of the bearing, and the lowest oil level is rarely lower than 1/4 of the diameter of the downmost ball bearing.

7. Check and clean cooling water pipes and the cooler. When the scale buildup of the cooling water pipes and the cooler have seriously weakened the cooling effect, acid cleaning shall be practiced, and the concentration of hydrochloric acid solution used shall be 5%-10%, and then rinse in clean water.

fit shall be 0.02~0.04mm

3. The clearance between the bearing and the bearing box shall be 0.03~0.05mm.

4. The radial clearance of the bearing shall be 0.11~0.18mm.

5. The oil level gauge shall remain unclogged and clear in vision.

6. The cooling water shall be free-flowing with proper amount of water, and the valves shall be of flexible operation.

(6) Maintenance of the housing

1. Check whether the housing is of strong fixation, whether exists the phenomena of desoldering, corrosion and etch off.

2. Check whether the housing and supports exist fatigue crack problem, if any cracks are found, repair welding shall be carried out in time; analyze the reasons and take corresponding countermeasures..

3. Check whether the manhole and shaft seal are in good order, the manhole shall shut closely and there exists no friction between the shaft seal and the main shaft.

1. Cracks are not allowed to exist in the housing; fixation shall be secured.

2. Tack weld shall be refrained between the housing and the supports.

3. Every weld joint is in good order and the welding shall be secured.

4. The sealing clearance between the shaft and the housing is generally 2~3mm, contact between the felt of shaft seal and

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the shaft shall be uniform, appropriate in tightness and tight in leak proof.

(7) Rotor reassembly

1. Bearing seat and external sleeve of the bearing shall be cleaned up prior to rotor reassembly, the rotor shall be carefully handed during the process of reassembling to prevent the occurance of equipment damage.

2.The alignment of the main shaft can be performed through adding washer under the bearing seat. The external sleeve of the bearing and the bearing cover shall be cleaned up prior to getting the bearing cover back in position, the clearance between the bearing cover and the topside of the external sleeve of the bearing shall be measured accurately with the method of Pressing Lead Wire generally.Perform the measurement twice and the difference between the two measurement results shall not significant. Determine whether it is necessary to add washer or not in the joint surfaces of the bearing seat and the topside of the sleeve according to the measurement results in order to have the clearance between the external sleeve and the bearing cover complied with the standard.

The lateral error shall not exceed 0.1mm/m after the alignment of the main shaft; the washer number usually is not more than 3

2. The contact angle between the external sleeve of the bearing and the bearing seat shall be 90°-120°; clearance on both sides shall be 0.14- 0.20 mm. Examination of the contact surface between the external sleeve and the bearing seat shall be practiced if the bearing seat needs being replaced.

3. Clearance between the external sleeve of the bearing and the bearing cover: clearance of the coupling side: 0.00-0.06mm; clearance of the impeller side: 0.05-0.10mm.

4. The joint surface of the bearing seat and the bearing cover shall remain clean and well connected, and a 0.03mm thick feeler gauge cannot be inserted.

5. The radial clearance between the end cover

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and the shaft is not more than 0.10mm; packing seal shall remain good condition..

6.Thrust clearance shall be 0.08-0.12mm.

8) Damper regulator maintenance

1. Check whether the switch of the damper regulators are flexible, whether the actual turndown ratio consistent with the indication.

2. Check whether damage such as cracks exists in the shaft of the damper, replacement shall be performed if any cracks exist.

3. Check the degree of wear of the damper, and perform replacement if a set value is exceeded.

4. Check whether distortion and wear case exist in the damper, replacement shall be performed if the damper is of gross distortion.

5. Check whether cracks exist in the damper, whether the transmission device is in good order.

6. Check whether distortion exists in the damper regulator and regulating ring.

1. The switch of the damper regulator shall be flexible, and the indicaion shall be consistent with the actual turndown ratio.

2. Damper regulator shaft shall be free from cracks.

3. If the shaft of the damper has been worn away more than 1/3 of the original diameter, replacement shall be performed.

4. If the damper has been worn away more than 1/3 of the original diameter, replacement shall be performed.

5.If any cracks exist in the steel damper, repair welding shall be performed; transmission device of the damper shall be in good condition and be free from unsmooth stagnation.

(9) Preliminary operation of the fan

1. Clean up the gas duct that connects to the housing prior to closing the manhole, and hermetic performance should be assured

2. Check whether the cooling water is free-flowing and keeps sufficient flow rate, check whether the oil temperature and oil

1.Preliminary operation time of the fan is 4-8h.

2. The axial and horizontal vibration of the bearing shall be ≤0.08mm during the

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level are normal.

3. Check the inlet guide damper regulator to make it in closed position.

4. Familiarize with the position and function of the buttons that switch off the power in situ.

5. Get ready the relevant measurement instrument and apparatus.

6. Prior to switching on the fan for perliminary operation, startup conditions shall be confirmed by maintenance controller and operators.

7. Measure the vibration condition of the bearing after the fan starting and running properly If vibration exceeds a set value, analyze the reasones or perform dynamic balance test.

8. Apart from measuring the vibration value, the bearing temperature and the current values when the air throttle is in various turndown ratio still need to be recorded regularly during the overall preliminary operation process; check whether such abnormalities as friction, oil leak, water leakage and air leak exist.

preliminary operation.

3. Bearing temperature is less than 75 .℃

4. The fan runs properly, without abnormal noise from running.

5. The damper switch shall be flexible and correct in indication.

6. All of the seals shall be oil-proof, watertight and airtight.

Attachment:SFY15F-C5A Performance Curve of the Fan

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0 15 30 45 60 Q(m3/s)

0

1300

2600

3900

5200

6500

P(Pa)

p=.797kg/m3 n=1490r/min

5.2 Force draft fan

5.2.1 Technical specifications force draft fan

1.1 General information

Fan type FAF20.4-10-1

Project number 2007-19

Year of build 2007

Name Vietnam Quang Ninh First-stage 2X300MW Thermal Power-generation Units Project

Installation site Quang Ninh Power Plant

Air volume (m3/s) 177.60 (T.B) 140.80(BMCR)

Total pressure rise of the fan (Pa) 5267(T.B) 3660(BMCR)

Inlet medium temperature( ) 39.00(T.B) (BMCR) ℃

Inlet medium density (kg/m3) 1.1120(T.B) 1.1680(BMCR)

Fan efficiency (%) 80.91 (T.B) 86.15 (BMCR)

Fan power (kw) 1135 (T.B) 605(BMCR)

Fan rotate speed (r/min) 1470

Motor power (kw) 1250

Motor rotate speed (r/min) 1482

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1.2 Mechanical parameters

Fan inside diameter φ2040

Impeller diameter φ1000

Impeller series 1

Blade model 16NA16

Blade number 16

Blade material HF-1

Connection of blade and blade handle Bolt

Bore and stroke of hydraulic cylinder φ336/H50MET

Blade regulating range 45o

1.3 Fan starting torque

Fan rotate speed n = 1470 r/min

Flywheel torque J = 0.25GD2 = 7373kgm2

Fan shaft power (under max. working condition) 1135Kw

Fan torque (under max. working condition) 7373Nm

Radial force of the motor shaft end FR = 2698 N

Axial force of the motor shaft end FA = 3000 N

Motor power Ne = 1250 kw

Being seen from the motor shaft end, the motor rotates clockwise, and the fan rotates anticlockwise.

1.4 Major Parts Diagram of the Fan

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Chinese English

风机扭矩 Fan torque

风机转速 Fan rotate speed

叶片全开 Full open of blade

叶片全闭 Full close of blade

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5.2.2 Technical specifications of force draft fan oil station

Fuel supply quantity: 25L/min；working pressure of hydraulic fluid: 3.0MPa； working pressure of lube oil: 0.3－0.6 Mpa; oli tank capacity: 0.25m3.

5.2.3 Maintenance of force draft fan and hydraulic fluid station


(1) Working condition analysis prior to maintenance

Record the following values prior to maintenance

1. Vibration values of the fan and the motor.

2. Motor no load current .

3.Fan outlet air pressure.

4. Bearing temperature.

5. Leakproofness of the fan housing, remarkable symbols shall be made out in leakage points.

Normal temperature60 ~70℃

.℃

(2) Disassembly of the upper part of the fan.

1. Disassemble shround, horizontal flange of the casing and the sound insulation layer of hoisting rings.

The shround shall be tight and complete, with no cracks and

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2. Disassemble the shround of inlet air and primary air and protection device.

3. Jack up the upper part of the fan casing by virtue of the upper cover jackscrew of the fan, and put the blade in “off” position. Hoisting and maintaining upper part of the casing in the air, suspension height shall be suitable for moving the casing without touching the blade.With that, remove out horizontally and put on the sleepers.

breaches; the rivets bear no bending deflection and elongation problem.Sealing ring and spacer are free from aging and cracks. Joint bolt and dowel pin shall be free from bending deflection and elongation problem.

3)Rotor disassembly

1.Remove regulating shaft and indication shaft from blade regulating device.

2. Detach the pipeline of main bearing box from the main bearing box.

3.Detach the secure flat steel that prevents hydraulic control head from reversing from hydraulic control head of the hydraulic regulating device.

4.Remove thermometer for bearing off the bearing box, loose the joint bolts that connect half coupling of fan side and intermediate shaft.

5.Hold up the intermediate shaft from the inside of gas inlet box, and maintain it straight and level to the greatest extent to prevent damaging diaphragm coupling.

6. Largest compression value of the diaphragm at the motor side is 4 mm.

7. Loose the joint bolt that connects flange of main bearing box and upper support ring of lower part of fan casing.

8.Lift the rotor.

Note: the rotor shall be maintained horizontal and balance in order to prevent blade from damage, lift it out in the vertical direction from the lower part of the casing, while ensure the dynamic being in off state.

9.Place the rotor on special support as that of placing impeller in the casing and blade is not

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allowed to touch ground or chassis

(4) Disassembly of blade handle bearing

The dismantled parts sunch as blade, major blade handle and bearing shall be numbered on the basis of hole number of blade handle (such as blade handle, balancer, blade handle bolt and Regulating bar) before being put in a certain place, and the number is not allowed to be deranged during installation again.

(5) Assembly of blade handle

Clean, maintenance and parts changing (if necessary) shall be performed in according to blade handle bearing assembly drawing.

Working face treatment:

Examine leakproofness of blade handle bearing with the method of pressure process.

Pressurize all of the blade handle bearings with a hydraulic pump, therefore, a pressure gauge shall be provided to each blade handle and each seal, the pressure shall be maintained at 2kg/cm2 for a continous 12 hours, and the pressure drop shall not exceed 0.2bar during the process of appling pressure.

(6)Assembly of guide bearing components

1. Overturn the impeller for 180º.(blade handle hanging on “steady bearing”.).

2. Push it into the hole of impeller guide ring through blade handle in accordance with the preassembled “guide bearing components” of figure 5-2 until the side surface touching the nut of blade handle.

3. Toggle sealing O-ring and maze-design sealing push-in blade handle and bearing tray, lubricating grease shall be applied to seals, fitting surface and groove side in advance.

4. Put preloaded spring (belleville spring) on the bearing tray which lies in the hole of guide ring.

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5. Preload the spring with retainer ring.

6.Loose blade handle nut slightly and take off the filling block under balance weight.

7.Tighten blade handle nut until the preloaded spring on bearing tray touching tapering annulus (torque is increased abruptly). Maybe blade handle nuts need further tightening to have the hlade handle nut aimed at the groove of blade handle.Wringing reversely is prohibitted.

(7) Disassembly and assembly of impeller

1.The disassembly force of wheel hub shall be fixed at 300kN.

(8) Coupling maintenance

No parts of RIGIFLEX coupling with detachable flange hollow shaft is suffered from friction and wear. The ratcheting of the flexible coupling is pinned; its diaphragm is made of special high grade spring steel, and the diaphragm shall be configured in pair in order to allow the connected machine to move freely in three directions.Such RIGlFLEX coupling needs no maintenance and lubricating, and is unlikely to be out of commission..

1.Assembling:

Loose joint bolt from the complete set of coupling, disassemble intermediate shaft. The heating temperature of coupling shall not exceed 150 ℃

when installing the half couping on mechanical main shaft head that is reday for connecting. Heating shall be carried out in heating furnace which can provide temperature control to avoid flame heating, since local overheating will weaken the strength of coupling parts.

Intermediate shaft shall be installed with proper distance “M”. Note: after the alignment of central connecting bolts of flange hallow shaft, the diaphragm is not allowed to be of bending but can only extend parallelly along the flange in normal position.

2.Alignment:

Perform precise alignment of the coupling,

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provided the opening size is Y

. Both of opening size Ymax and Ymin shall be measured out( figure 5-8). Displacement deviation will be caculated based on the measured value.

Table 5-2 Size Y used for aligning the coupling precisely

Allowance displacemnet of each end side (mm)

Coupling type

Opening

Y(mm)

±a1max ±r1max

MA

(Nm)

1001 23.5 3 6.5 410

Allowance error for the alignment of RIGIFLEX coupling with detachable ◆

flange hollow shaft

English Chinese

刚挠性联轴器 Grid-flexible coupling

中间轴 Intermediate shaft

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联轴器端面偏斜（角度）允许误差: Allowance error of the coupling end surface deflection (angle)

偏斜测量值: Measured deflection value

测量直径 Measured diameter

Allowance Error of Coupling Alignment◆

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Chinese English

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中间轴 Intermediate shaft


联轴器端面偏斜（角度）允许误差: Allowance error of the coupling end surface deflection (angle)

偏斜测量值: Measured deflection value

测量直径 Measured diameter

附件 VIII 中间轴找正允许误差 Attachment VIII: Allowance alignment error of intermediate shaft

Maintenance item


(1) Radial displacement:

r1＝Ymax-Ymin (mm)

100×r1 / r1max %＝△1

Refer to table 5-2 for the value of r1max.

(2)Axial displacement:

±a1＝(Ymax+Ymin)/2-Y (mm)

(Note:+ a1 refers to the couplings being detached from each other; -a1 refers to the couplings being combined.)

100×a1 /α1max %＝△2

Refer to table 5-2 for the value of a1max.

Generally, r1≤0.20mm will meet operation requirements.

(3) Allowable values of the radial and axial displacements interrelated percentage, which shall comform to the following formula:

△1 十△2≤100%

E.g.:if 40% of △1 has been used, 60% of △2 can be used at most.

With the alignment finished, tighten the joint bolts in accorance with the tightening torque of table

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5-2.

(9) Stagger angle measurement of the blade

Check whether on-off angles (position) of the max. and min. blades are +15° and -30°respectively. Methods: measure out the included angle between blade section and air flow, then check whether the measured angle matchs the indication value shown in blade angle dial.

Tightening Procedure Chart of Impeller Fixing Bol◆ t

Hydraulic Regulating System Chart of Force Draft Fan◆

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English Chinese

叶片： Blade

调节杆： Regulating bar

活塞： Piston

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液压缸： Hydraulic cylinder

活塞轴： Piston shaft

控制头： Control head

伺服阀： Servo valve


控制轴： Control shaft

指示轴： Indication shaft

回油： Return oil

压力油： Pressure oil


5.3 Induced Draft Fan Maintenance

5.3.1 Technical specifications of induced draft fan

Fan model: Axial Induced Draft Fan with Meridional Acceleration

Fan type: G158/273

Manufacturer: Shanghai Blower Works

Installation site: Vietnam Quang Ninh Power Plant

Project No. of Shanghai Blower Works:2007-20

Direction of rotation: The impeller rotates clockwise being seen from the direction of air flow.

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Assembly Schematic Diagram of Induced Draft Fan

Fan Aerodynamic Parameters:

Serial No.

Project Name

T.B

BMCR

1 Fan inlet caculated flow (m3/s)

281.39 232.5

2 System total pressure drop (kpa)

4053 2895

4 Fan inlet flue gas temperature ( )℃

138 127

5 Flue gas density (kg/m3) 0.85 0.883

6 Fan inlet dust content (mg/Nm3)

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7 Rotate speed r/min 735

8 Fan shaft power (KW) 1416 809

9 Fan efficiency (%) 79.33 79.63

10 Fan rotary inertia (J=0.25GD2)

330KgM2

11 Motor YKK710-8

5.3.1.1 Mechanical parameters

Fan inside diameter φ2740

Impeller diameter φ2730

Impeller series 1

Blade model 14G16

Blade number 14

Blade material 15MnV

Clearance between inside diameter of the casing and outside diameter of the blade 4-5.4mm

Regulating means: Inlet damper

Coupling type: Rigid-flexible coupling, specification: 5001Form14,

Support pattern: Double bracing

Weight of machine:( Heat insulating layer not included): 46152 kg

5.3.1.2 Performance curve

Fan type: G158/273

Customer: Quang Ninh Power Plant

Fan rotate speed: 735r/min

Motor power: 1500KW

Fan blade model: 14G16

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5.3.1.3 Fan starting torque

Fan rotate speed: n=735r/min

Moment of inertia of rotor: 330 kg.m2

Fan power (under max. working condition) 1416KW

Motor power 1500KW

Motor voltage 6600V

Being seen from the motor shaft end, the motor rotates clockwise, and the fan rotates anticlockwise.

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Chinese English

风机扭矩 Fan torque

风机转速 Fan rotate speed

进口导叶全开 Full open of inlet guide blade

进口导叶全闭 Full close of inlet guide blade

5.3.2 Function description

The fan is a variable stator blade induced draft fan designed and manufacured by our company with the imported technology of Germany “TLT” Corporation.

The gas passes throuth the inlet regulating device of gas inlet box, and then enters into impeller in a flow angle direction that corresponds with the inlet guide blade; it obtains the needed energy of overcoming resisitence derived from pipe networks in the impeller.This presents with total pressure rising of the gas.

In the variable stator blade induced draft fan, the realization of total pressure rising of gas medium in the impeller relies largely upon the increase of dynamic pressure, while the conversion of dynamic pressure to static pressure is realized in straightening guide blade and

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disffuser.

The impeller of the fan is designed in accordance with TLT developed G158 blade model, with the characteristics of high efficiency and easy fabrication, and its working condition is particularly well adapted for the induced draft fan of large scale power station.

5.3.2.1 Still Parts

Including the following components: (in the order of air flow direction)

Gas Inlet Box (52.00)

Flow through the rectangle inlet cross-section of gas inlet box, after a 90° turn, then axially flow into inlet guide regulating device (87.00) from outlet circular passage of gas inlet box.

Inlet Guide Blade Regulating Device (87.00) 125

Inlet guide blade regulating device is equipped with airfoil-shaped front guide blade, and connected with regulating mechanism, when the regulating mechanism acts to adjust, the fan inlet front guide balde is brought to different positions to change the flow angle of fan inlet, thus higher efficiency can be attained in different working conditions to adapt to the requirements of boiler variable working conditions.

Casing (51.00)

It is an outer shell of the fan. By suitable treatment on the inside diameter, a clearance of 4-5mm between the casing and impeller shall be ensured.

There exists a set of fixed straightened guide blade (rear guide blade) in the backside of the casing.

Diffuser (55.00)

The diffuser bears a certain diffusion angle; with the area increase of the flow passage, the flow rate of the fan will decrease, converting the dynamic pressure to static pressure will made transportation and deinstallation much easier.All of the above still parts are allowed to be dissected.

5.3.2.2 Rotor

Mainly consists of:

Bearing box (11.00):

In consideration of thermal expansion influence, the casing and the diffuser is flexibly connected by shroud so that thermal expansion cann’t be a danger to the rotor under any circumstances.

There exists two bearing boxes to support impeller weight and sustain the axial thrust derived from air flow during the operation of the fan. Bearing box adopts split type, and is featured by easy and reliable adjustment and installation.

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Impeller (12.00):

Impeller consists of impeller casing, stud and blade, and the whole impeller adopts welding structure to reduce weight. blade the blade is produced in line with certain mode line heat moulding, and welded on to wheel hub at a certain stagger angle. The impeller connects with the main shaft firmly through high strength bolt.

Shaft description (11.11)

In order to faciliate the assembly and disassembly of impeller, the shaft is designed to be sectional and flange is used to connect adjacent two sections; flange that connects the impeller is welded on the shaft. Power transmission between coupling and shaft is delivered through fit key, while power transmission between fan shaft and impeller is realized by virtue of fitted bolt.

Bearing description

Bearing block description

Double-row self-aligning spherical roller bearing is installed in horizonally-split bearing, and cylinder hole is applied to the shaft directly.

Top and bottom bearing boxes are connected through four bolts and riveted through two taper pins to guarantee correct installation, the end cover of the bearing boxes is a one-piece structure and is connected through bolts with bearing box, the footing of bearing box is provided with bolt hole to faciliate the connection with bearing box chassis through bolt, moreover, alignment hole used for aligning with taper pin is furnished.

Bearing box is especially designed for fixed bearing and floating bearing, so it is unnecessary to house additional retaining ring in the bearing box. Total axial displacement of floating bearing approximates to ±10mm.

Frame description

Floating bearing block is located on the bearing bracket of straightening guide blade; motor YKK710-8(29.00) has its own chassis; bracket of fixed bearing box (11.14) is directly mounted on foundation.

Coupling carries coupling guard to prevent contact with the environment.

Transmitted force of gravity and all possible equilibrant force are taken into consideration when designing the brackets.

Grid-flexible coupling (25.21,25.22):

The project adopts 5001form14 type grid-flexible coupling, the main shaft connects with the fan and the motor through coupling respectively. This type of coupling can perform a certain amount of axial, radial and angular displacements, and can compensate the thermal expansion during unit operation, various displacements incurred in the process of manufacture and installation to ensure steady operation.

Cooling fan

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Floating bearing box of the fan is located within straightening guide blade loop, in order to be free from the influnce of medium temperature, it employs 4-72-11 No 3.2 centrifugal fan, which is introduced by cooling air duct from the backside of diffuser.

Thermometer

Temperature of the main bearing of the fan is measured through resistance thermometer, and each bearing block is furnished with three thermal resistance thermometers to measure the temperature, collected signal will be sent to central control room.

Vibration-measuring detector: each bearing block is provided with a vibration sensor to measure the vibrating amplitude of bearing block in horizontal direction.

Other spare parts

The fan is also equipped with instrumentation for gauging bearing temperature vibration, oil level and fan surge, which can provide telemetering, monitoring and interlocking functions to ensure the operation stability of the fan.The fan is also provided with interface for measuring gas pressure and temperature for the user to detect air volume and air pressure.

5.3.2.3 Regulating device

Regulation of the fan capacity is achieved by means of the inlet guide regulating device. When the regulating device is adjusted, the stagger angle of fan inlet guide blade will be adjusted synchronously. As for a specified fan capacity, optimum prewhirl can be made available to medium by regulating front guide blade stagger angle of the impeller. The fan can achieve higher efficiency than throttle governing type under variable working conditions. Because the air flow directions are almost axial in the simple throttle governing type and bear no relation to the actual capacity of the fan.

The inlet regulating device adjusting the inlet static blade angle by means of the regulating mechanism of electric actuator is feasible. Electric actuator operates on the basis of automatic control provided pulse signal as required by plant capacity. Electric actuator connects with the position loop of inlet guide blade regulating device by means of steel operating lever. When the electric actuator acts, position loop rotates together, thereby regualtion can be achieved through winch, connecting rod and the changing of the inlet guide blade angle.

5.3.3 Parts description

5.3.3.1 Impeller

Welded structure of the impeller can relieve the its rotary inertia, the blade is formed by uniform steel in line with certain mode line heat moulding. The impeller and the main shaft of bearing box is jointed togrther through adapter sleeve. In order to ensure the clearance between the impeller and the casing, outside diameter of the impeller is guaranteed by lathe and inside diameter of the casing is guaranteed by vertical lathe. Being seen from the air flow direction, the impeller rotates anticlockwise.

5.3.3.2 Bearing box

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Bearing box adopts split type; bearing is cooled by cooling water. They are safe, reliable and of compact connection. Each bearing box is equipped with double-row self-aligning spherical roller bearing to support impelller weight and the axial force incurred by the pressure rise of the fan.

5.3.3.3 Grid-flexible coupling

The unit employs grid-flexible coupling transmission, which is manufacured by our company with the imported technology of Germany BSI Corporation and is a coupling that can achieve actual balance.It can balance various displacements to be generated during the process of installation and operation of the fan. (including axial displacement, radial displacement and angural displacement) the coupling is very convinent for alignment. No parts will suffer friction or fret during the operation of grid-flexible coupling. The flange of such coupling is made of low alloy steel. Elasticity film with high dimensional tolerance requirement is made of special high quality steel. Paired configuration of the elasticity film can allow the connected machine to move in three directions freely. Maintenance is not required for this kind of coupling. It is unnecessary to lubricate, and it can work without fault below the temperature of 150°C.

5.3.3.4 Inlet guide blade regulating device

In the actual cases, fan will meet the situation of various operation requirements. It will

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change the inlet air flow angle through regulating inlet guide blade angle, so that the fan can answer the boiler to gain better performance under different operating work conditions (loads). this is the so-called prewhirl.

1.Regulating device shell 2. Regulating position loop3.Roller (radial direction) and bolt

4.Roller (axial direction) and bolt 5.Connecting rod 6.Regulating blade

7.Top regulating shaft bearing 8.Top shaft of root regulating bearing

9.Top shaft 10.Root shaft 11.Joints

5.3.4 Induced Draft Fan Maintenance

Maintenance Item

Workmanship and Precautions Quality Standard

1. Motor bearing

1. Open the top cover and remove the oil ring. Open the upper bearing and measure the top clearance and side clearance to duely record before maintenance.

2. Use jack to jack the rotor so to remove the bottom half bearing and spray with lead red to grind at the shaft gland. Check the contact surface and repeat the grind several times till the joint satisfies the

1. The top clearance shall be 0.32－0.48mm；the side clearance shall be one half of the top clearance, that is 0.16-0.24mm.

2. The clearance between the oil seal diameter is 0.40-0.60mm

3. The tension of the joint between the upper bearing and the bottom bearing shall be 0.00~0.03mm.

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specifications.

3. Clean the bearing seat inside and check overall the bearing casing.

4. Put down the bottom half bearing and remove the jack and put the rotor to the shaft bearing. Measure the side clearance. Take 3 measurements at each side and use lead method to gauge the top clearance.

5. Check and repair internal oil seal and measure the clearance.

6. Measure the clearance between the shaft beraing and bearing casing.7. Check the oil ring and repair.

8. Check the clearance of external oil seal and repair. 9. Clean the oil piping and replace with new flange gasket.10. Clearly mark the position before maintenance or find the original marking. Shaft bearing oil inlet has to be aligned with the oil inlet hole on the bearing casing.

1. The front and rear bearing seat oil inlet has to be installed with throttle orifice.

4. The contact of the bearing shall be 2~3contacts/cm2.

5. The medium gasket of the bearing shall not exceed 0.30mm.

6. The clearance between the bearing and shaft gland shall be 19mm.

7. The rear bearing seat has to be insulated. The leg has to be on an insulation plate. The bolts have to use insulation tube and oil pipe has to have insulation sleeves

. The oil ring has to be Ok. If it is worn or deformed, replacement must be done. The bottom half has to be immersed in the bearing seat.

9. The throttle orifice oil inlet pressure shall be around 49kPa and the oil filter pressure around 98kPa. There shall be little difference between the front and rear pressure.

2. Maintenance and Service of Diaphragm type coupling

1. Check whether diaphragm spring is Ok.

2. Check whether the bolt connecting the spring is loose.

3. Check whether the coupling in the middle of the half coupling is Ok.

1. The spring gasket shall be complete.

2. The joint shaft and middle flange shall be complete without any damage.

3. The bolts connecting the spring shall be tight.

4. The temperature of the joint shaft when being heated shall not exceed 150 . No heating from ℃

fire directly to prevent any

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overheating.

5. Tighten the coupling on the shaft with a clearance of 0.00－0.04mm.

3. Disassemble the rotation part of the fan

1. Remove the bolts on the casing and the position pin and the casing. Lift the upper casing according to TLT rules. Care shall be given to the lifting and damage to the blade is prohibited.

2. Cut 0.5-1mm from the front part of the middle shaft hood and make two adjustable support to support the middle shaft. Then remove the flange bolts between the middle shaft and coupling and use bolt to tighten the middle flange in its opposite direction to press the spring to contract so that there is clearance between the middle flange and middle shaft. The clearance is to be used to lift the impeller. 3. Loosen the shaft gland round nut safe and the round nut.

4. Get ready the special tools for disassembling the impeller. When disassembling the impeller, first lift the impeller to prvent damage to the blade. After disassembling, the impeller shall be placed to special support or timber and covered with waterproof materials to prevent dust.

5. Remove the disaposable bolt between the bearing seat and casing. 6. Remove the temperature measurement at the bearing seat together with oil inlet, return oil piping and pipe and packed with plastics.

7. Slowly lift the bearing box and place it on the asessbling support

1. The torque for the disposable bolt connecting the bearing casing and casing shall be 250Nm.

2. The torque for impeller lock bolts (disposable)shall be 300Nm.

3. The maximum and the minimum clearance between the bearing rear end cover and casing are 0.80mm and 0.20mm respectively. They shall be sealed tightly.

4. The added oil shal comply with specfications made by the manufacturer.

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and fixed.

8. Loosen the bearing end cover screw and remove the impeller end cover9. Put the bearing in an upright position and extract the rotor.10. Use a puller to remove containment shell, and remove bearing end cover and retaining ring and twin thrust bearing.11. Check, clean or replace bearing. 12. Replace all sealing parts. 13. Check whether the bearing seat casing and the end cover is Ok. 14. The order of sequence for assembling and disassembling is opposite and clearly measure the clearances and record. 15. Precautions during disassembling: mark every part before disassembing and assemble according to the marks made. All high tension bolt shall be tightened with specified torque. On the bolt shall sprayed with supramoly. On the bearing seat end cover shall be sprayed sealants so that it is oil leakage free. 16. After placement of the rotor, no gasket shall be added between the bearing seat and casing.17. Impeller shall not be in any leaning position. Use filler gauge to measure the clearance at the bottom of the coupling. The bolts can only be tightened when the 0.03 filler gauge can not be inserted.

4. Check the Main Shaft Gland and its level

1.When the rotor is positioned, use level to measure the level of the coupling shaft gland.

2. Check the key groove and key and upper tooth and repair

3. The key groove is Ok with no side

1. The shaft gland shall be smooth, without cracks, curvers, or burrs. If there is abrasion, repair needs to be made. The ovality and concentracity outside of the shaft gland shall be 0

2.The impeller assembling

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clearance and the tooth is Ok.

position shall shine with bright yellow colour after copper spray. There shall not be any black colour.

3. The level of the shaft shall be ≤0.06mm/m.

5. Middle Shaft 1. Check the appearance of the flange, the screw holes on both sides to see whether there is damage.

2. Use microcalipers to measure the Out-of-roundness.

3. Meausre the bending on a specialized motor support.

The flange at both ends shall be complete without any damage. The screw hole is Ok. The hollow shaft shall be no cracks, damages. The balance weight shall be fixed and tightened. The bending shall be ≤, the out of roundness shall be ≤0.02mm.

6. Impeller maintenance

1. Remove the fouling on the impeller.

2. Before removing the hub, check whether there is seal on it. If no, first make seals on the hub.

3. Measure the wear of the induced draft fan and the blade and record duely.

4. There shall be no cracks and deformation from appearance of the blade.

5. Remove the hub from the main shaft and place it on a special support.

1.The blade surface is smooth and without damage, deformation. The hub is complete.

2. Inside the hub were no impurites and foreign matter.

7. Measure the radial clearance between the blade and casing.

Measure the up, down, left and right. If the clearance is too small, use grinder to grind the blade or casing wall.

The tolerance for the clearance between the blade and the casing is 5~7mm.

8. Crosscheck with the openness and closure of the inactive entry

1. Close the inactive entry 100% and check whether the trundown ratio is consistent or not. If not, then adjust the external articulated parts so that the turn down ratio is the same. At

When the blade opens +30° or closes -75°, refer to the casing scale.

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the same time, the casing scale indication shall read －75°. The position at this time shall be set as 0%.

2. Use the actuator to manually adjust the entry blade to fully open. At this time, the scale indication on the casing shall read 30°. The position at this time shall be set as 100%.

3. Fix the position of stop pad for the actuator.

9.Alignment of the fan and the middle shaft motor.

1. Use fan as the reference and move the middle shaft to find the concentricity. Then move the motor to find the concentricity between the motor and middle shaft.2. After

alignment and motor runing without load, connect the coupling and remove the temporary support for the middle shaft and return the shaft hood and coupling hood.3. Use Dial Indicators to measure the center.

1. The radial clearance between the coupling hood gland seal and coupling shall be 1~2mm

2. Requirements for the alignment of diaphragm coupling at the impeller side and motor side before the pre-lift of the motor shaft: radial displacement r1≤0.15mm; axial displacement a1≤0.10mm. The requirements of alignment of diaphragm coupling after pre-lift of motor shaft: motor side upper opening and impeller side downside opening radial displacement r1=0.20~0.30mm; left and right opening radial displacement r1≤0.2mm; up, down, left and right opening axial displacement a1≤0.15mm.

3. Alignment requirements after the coupling is pre-elongated:axial displacement a1=2.2±0.15mm, radial displacement r1≤0.2mm.

10.Casing Inlet and outlet compensator maintenance or

1. Repair the compensator.Replace if there is serious damage.

2.After repair, check and repair any

1.The compensator shall be complete, without damage.

2. The tightening plate shall be

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replacement air leakage. complete.

10. Induced draft fan cooling fan

1.Clean the filter.

2. Check impeller wind duct

3. Reversible deflector maintenance.

4. Motor maintenance together with its electric supplies. motor.

5.Trial operation

l. The filter, after cleaning, is complete.

2.Both the impeller and the fume duct is Ok, without fouling.

3. No vibration and abnormal noise during trial operation.

12. Induced draft fan inlet and outlet fume duct leakage repair

1. Check the inlet and outlet fume duct. If there is leakage, repair by welding with iron plate to remove the leakage.

1. Replace is the abrasion reaches 1/2 of the thickness.

13. Induced draft fan airinlet chamber and diffuser examination and leakage repair

1. Eliminate manhole air leakages

2. Check the airinlet chamber and diffuser. If there is leakage, repair by welding with iron plate to eliminate the leakage.

1. The manhole is complete, without air leakage.

2. Replace the inlet chamber, casing, and diffuser if the abrasion reaches 1/3 of the thickness.

14. Outlet guide vane examination and repair by welding

Check and clean the outlet guide vane. If it is worn, repair by welding.

Replace if the abrasion of the outlet guide vane reaches 1/2 of the thickness.

15. Induced draft fan inlet and outlet isolating valve maintenance

1. Check the whether the damper switch is correct or not and adjust.

2. Check whether the ram pins are complete and Ok.

3. Check whether the bearings are Ok and whether there is lubrication oil.

1. The baffle is complete and its opening and closure is flexible. The turn down ratio on the inside and outside is consistent.

2. The ram pins are complete, without damage.

3. No corrosion, falling, or congestion of the bearings. Inside the bearings is there lube oil.

16. Trial operation to measure the vibration and calibrate the

1. After maintenance and in the trial operation, the fan must satisfy the following:

1) No impurities within the rotation

1.The vibration value ≤0.10mm.

2. The bearing operates Ok, without abnormal noise, and oil leakage. The bearing temperature

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balance.

parts.

2) Normal oil circulation established.

(3) Remove scaffolding and clean the site.

(4) People shall stand in the axial direction in case of accidents.

2. Measure the vibration value during trial. Check whether is abnormal noise from the leg screws and the rotation parts.

3. Calibrate motion balance if necessary. The balance weight shall be welded to the rear side of the hub.

shall not exceed 90 .℃

3. The trial operation shall be 2 hours.

4. The non-static blade can be adjusted flexibly.

5. After balancing, the thickness of the balance weight shall be less than 10mm. The welding area shall satisfy with the minimum area on TLT rules. If tightened with bolts , the size of the bolt section shall be at less on half of the welding area. 6. Regarding the vibration caused by blade imbalance, the balance weight has to be marked and logged so next time it can be removed when replacing blades. After removing the rotor blades, according to TLT rules, it shall be marked with a bright color “BLADES”

5.4 Maintenance of Fume duct and Air duct

Fume Duct, Air Duct and Flange

Maintenance Item

Workmanship and Precautions Quality Standard

1. Check the air duct.

1. Check the air leakage of the air duct.

2. Check whether there are defects such as cracks and deformation.

3. Check whether there are weld openings, cracks in the air duct strengthening parts. .

1. No cracks on the air duct iron plate and strenghthening parts.

2. The air duct shall be sealed without air leakage.

2. Air duct and flange maintenance

Check whether there is weld openings in the air duct. 2. Air duct flange packing seal maintenance.

3. Weld to repiar or remedy the cracks in the air duct and strengthening parts to

1. No welding defects shall no noticed on air duct welding. The joint shall be smooth.

2. No cracks on air duct and strenghthening bars.

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eliminate the cracks

4. After the air duct maintenance, the impurities shall be cleared out and the temporary fixations be removed. 5. Do air pressure examination and check the seal quality.6. If there is leakage, it shall be handled timely. 7. If the air duct vibrate, analyze the causes and handle them accordingly.8. Air duct thermal preservation.

3. No random flame cutting on the flange bolts. Mechanical processing shall be adopted.

4. After pipe and equipment maintenance, immediately clear all the foreign matters, dusts and temperary fixations.

5. There shall be seal jacket between the air duct and the equipment flange. The jacket shall not enter either the air duct or the equipment. Both sides of the jacket shall be sprayed with seals.

6. The rear center line deviation after the air duct maintenance shall not be bigger than 30mm.

7. The air pressure experiment shall comply with regulations.

Fume Duct and its Accessories

Maintenance Item Workmanship and Precautions Quality Standard

1. Baffle and Plugboard and their Operatio Mechanisms

1. Check the new baffle and plugboard before installation. Do disasembly check if necessary.

2. Leave heat expansion clearance as per the drawings.

3. Gland seal maintenance and replacement to eliminate leakage.

4. Mark on the shaft gland corresponding positions of the baffle and plugbards as per the actual positions. Their opening and closure shall not be limited.

5. Maintenance and check the opening degrees of combination type baffle.6. Check the seal of the baffle. If worn, replace immediately. 7. Check whether

1. The baffle and plugboard shall comply with the design requirements.

2.The expansion clearance shall comply with the design requirements.

3. The gland seal shall be Ok, without leakage.

4. The opening and closure of the baffle and plugboard shall be accurate and flexible.

5. Regarding the combination type baffle, the opening shall be syncronized and the turndown

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the indication in the remote control equipment is correct; whether the welding seat opens; whether it is leveled. 8. Check the abrasion level on the mechanisms with universal joint. Depending on the level of abrasion, to decide whether it needs to be repaired or replaced.9. Check the marking for open and close and also the limiter for fully open and fully closure. 10. Clean the fouling in the fume duct.11. Check the abrasion level of baffle in the fume duct. If there is serious abrasion, replace immediately.

ratio consistent.

6. The operation mechanisms shall be convenient to use with correct indications. The seating plate shall be fixed and leveled.

7. The universal joint shall be Ok, and the abrasion degree shall not exceed 1/10. The rotation degree shall exceed 30°.

8. The opening and closure indication shall be clear and comply with the turndown ratio

9. The fume duct shall be clean, without fouling.

2. Extension maintenance

1. Check the movement of the extension to ensure free movement. 2. Replace the fillers each time the extension is maintenanced. The flange bolt to the filler shall be flexible.3. Eliminate cracks on the extension. 4. Check the abrasion level of the internal tongue in the wavy extension. If it is serious, either repair by welding or particially replace. If the extension as a whole is worn, or the wavy extension is corrosioned seriously, replace them as a whole.

1. The movement of the extension shall be flexible.

2. The fillers in the filling extension shall comply with standard.

3. No defects such as cracks on the extensions.

Support and Hanger maintenance

1. Check the support and hanger of the fume duct. If there are cracks, loosenings, deformations, they shall be handled immediately.

2. Check the movement and the abrasion level of the movable support and hanger.

3. Check the spring in the spring hanger to see whether there are cracks or not.

1. The support and hanger shall be complete and Ok, without breakage, cracks, loosening, and deformation. The load on the hangers shall be balanced.

2. The movable support, after being loaded, can still freely move. Replace the support if the abrasion exceeds 1/3 of the walling of the support.

3. The spring on the hanger shall

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comply with design requirments. No cracks shall be on the springs.

5.5 Air Heaters and Pipe Maintenance

Air Heaters Maintenance

Maintenance Item Workmanship and Precautions Quality Standard

1. Check the air heaters

1. After stopping the boiler, water shall be circulated to check whether is leakage from the air heaters. Record the leakage position if there is any.

2. Check the abrasion level of the air heaters. Replace the worn parts.

3. Check the corrosion degrees of the air heaters and clearly record them. Replace the parts which have serious corrision degrees

4. Check the fouling conditions among the radiators of the air heaters. Clean the fouling timely to ensure the fume flow area.

1. There shall not be any leakage from the air heaters.

2. The abrasion level of the air heaters shall not exceed 1/3 of the original thickness.

3. There shall not be fouling in the air heaters. The fume flow area shall not be less than 90% of the design area.

2. Maintenance of the Air Heaters

1. Replace the damaged air heaters.

2. Hydrotest must be carried out before the air heaters being installed.

3. When removing the damaged air heaters, measures have to be taken to prevent damages to other heaters and to ensure the security and safety of the site.

4. The welding quality shall pass deficiency free test by radiation.

5. Hydro test for the whole set shall be carried out after replacement of the air heaters to ensure there is no leakage.

6. Hydrotest check shall be executed on each maintenance and service after the air heaters are put into operation.

1. New air heaters have to undergo hydrotest to ensure no leakage. The test pressure is 1.25 times of the work pressure.

2. After the air heaters are put into operation, the hydrotest pressure shall be its work pressure. Normally a hydrotest with 1.25 times of the work pressure shall be carried out around every 6 years.

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6 ESP

6.1 ESP Technical Specifications

Name Technical specifications parameters

Manufacturer Shanghai Metallurgical & Mining Machine Manufactory

Product type FAA ESP

Nominal flue gas flowing area(m2)

Flue gas flow (m3/s)

Pressure drop of ESP proper (Pa)

Design efficiency (%)

2*269

258.98

<195

≥99.75%/≥99.7%

6.2 Structure of ESP

The method utilizing HV electrostatic field to act on dust gas is called electrostatic precipitation and the equipment is named electrostatic precipitator (ESP). Its operation principle is that: in HV electrostatic field, gas is ionized by the electric field force into electrons and ions. These electrons and ions move under the action of electric field force and combine with dust making dust charged. Dust particles with negative electric charge are collected at anode (collecting plate), discharged and adhere to the anode. Meanwhile, particles with positive charge are collected at the cathode. When dust accumulation reaches a certain thickness, dust particles will be peeled off from the collecting plate by rapping mechanism and drop into ash bucket. The dust collecting process finishes.

Major features of ESP are: high efficiency; low operation resistance; low operation cost. However, cost of ESP is high, and its volume is huge requiring a large area. In addition, it has strict requirements on manufacture, installation and maintenance. Efficiency is easily to be affected by operation factors. Therefore, operators should have high technical capability.

An ESP is composed of one or more chambers and fields. Devices include discharge electrode, collecting electrode, rapping unit, ash bucket, ash discharging device. So-called “chamber” is a sub branch of transverse flue gas path. There may be single chamber, double chamber or triple chamber according to flue gas volume. So-called “Field” is a dust removal unit along with the direction of gas flow. Each unit has an independent working system.

6.3 Maintenance of ESP

1. Get Equipment Conditions before Maintenance:

Include: operating parameters of electric fields before ESP outage (secondary voltage, current,ratio of putting into operation, operation hours, etc.); equipment defect and treatment records; summary of last overhaul and operation maintenance logs since last overhaul (such as technical improvement and equipment replacement).

2. Prepare Maintenance Schedule:

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Include: progress control schedule; maintenance procedures; labour arrangement and diciplines coordination; special technical provisions and safety procedures.

3. Material preparation and site arrangement:

Include: preparation of spare parts, maintenance material, construction tools, safety facilities, lighting tools and protective clothes; division of working area and stack area; management of site spare parts.

4. Preparation of technical record forms:

Include: measurement record forms of electrode distance, record form for no-load step-up test of electric field universe point, distributing test of air flow, rapping acceleration test, air leakage ratio test record forms(if necessary).

Safety Measures and Precautions during ESP Maintenance

1. Maintenance activities inside ESP and at high-altitude should be performed as per requirements specified in [Working Regulation of Power Safety].

2. Maintenance inside ESP should be carried out after boiler is shut down and cooled by natural cooling or draft cooling, and the temperature of the electric field is below the safety value as well as the residual flue gas is exhausted. The safety temperature is 40oC normally. Properly extend the safety temperature limit as required and strengthen protective measures. However, the temperature limit should not exceed 45oC.

3. Before enter ESP electric field, shut off the power supply, lay grounding wire and hang warning sign.

a) Shut off power and hang warning sign: cut off the HV power supply with an obvious breaking point and hang the warning sign. Cut off the power supplies of the ESP auxiliary equipment (rapping, ash handling, and electric heater) and hang a warning sign.

b) Discharge electric field and lay down grounding wire: after verifying the HV power is shut off, put the HV disconnector to position “Power-Grounding” and lock it and hang warning sign. Discharge the electric field with the grounding wire. Then hang a warning sign written with “grounded”. Before open b manhole to get in electric field, discharge the manhole and electric field. Insulation glove should be worn during discharging and laying grounding wire.

4. Power supplies for electric field maintenance:

a) Voltage of the portable light should not be higher than 12V.

b) If a 220V or 380V maintenance power supply is needed to be routed into the electric field, a guardian should be appointed outside the electric field manhole to quickly shut off the power supply equipped with earth leakage protector in case of emergency. The earth leakage protector should be qualified. Power wires should be well insulated to avoid any accident.

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c) Welding wires routed into electric field should be well insulated without any damage or leakage.

5. For maintenance inside electric field, working bags should be used for material transportation. Count the material and tools before each commence and after each completion. Remove debris produced by maintenance and do not leave them at electrodes to prevent them from dropping into ash hopper or left in the electric field.

6. For maintenance inside electric field, there should be at least two personnel with another for guardian outside the ESP manhole.

7. Special safety measures should be arranged for specific maintenance items:

a) Safety measures during no-load step-up test of electric field: the key points of the activity are the combination of mechanical and electrical works simultaneously, power-on test and discharge treatment.

b) Cross working. Parallel installed cable should be supplied on the HV side when double power supplies are stepped up. Special safety measures include preparation of test plan or procedures, determination of person-in-charge, guardian from appointed personnel, reliable communication, guard fence and suspension of warning signs. It should be approved by the safety supervision department of the factory when entering the electric field to observe discharge point.

c) For the maintenance of equipment in the HV switch cabinet of the latter stage electric field maintenance, the damage caused by the drift charge from the former stage should be avoided.

6.3.1 Maintenance of Cathode Wire and Anode Plate


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Remove ash inside electric fields

1. Only at least 12 hours after the boiler flameout can open the manhole for further cooling so as to avoid the deformation of parts inside ESP caused by sudden drop of temperature. Access can be available only if the temperature inside electric field drops below safety value.

2. Check before removing ash: check the ash accumulation inside electric field including accumulation position and degree. Check ash accumulation on electrode plate and electrode surface.

3. Cleaning of ash accumulation in ash hopper: before manual ash cleaning in electric field, start the continuous cathode/anode rapping and trough plate rapping for mechanical cleaning. Discharge ash through normal ash handling method. For ash removed out by manual method from ash hopper of the electric field should be stored in bags manually for transportation. For cleaning ash in the ash hopper, personnel should be dressed with cotton protective clothing, boot and dust mask to avoid any injury. Ash releasing port and maintenance passage should be bright without barrier. When opening the manhole, do not face to the front of manhole.

4. Ash cleaning in electric field: the cleaning sequence should be manually performed from upper to lower and from inlet to outlet by means of compressed air blowing. Water flushing is prohibited.

Keep original check record and registration; analyze the cause of abnormal ash accumulation to provide reliable information for maintenance.

Avoid discharging ash through manhole.

No ash accumulation, scaling on the surface of parts after cleaning ready for the maintenance.

When cleaning the ash accumulation on the anode plate, do not shake it to avoid deformation of anode plate. thickness of ash accumulation should be less than 5mm.

(I)Anode plate maintenance

1. Check the deformation of a single anode plate and correct the difference.

2. Check corrosion and electric

1. Flatness error <15mm, diagonal error <10mm.

2. No burr or sharp corner

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corrosion of a single plate and repair damaged anode plate as well as grind the burrs and sharp corner.

on the surface of plate.

(II)Anode plate maintenance

1. Check the fixing pin roll on the upper cleat of the anode plate, buckle bushing and fixed-position welding; check the deformation and abrasion of the square hanging lug and hanger. Check for any splitting around electrode plate tightened by the buckle bushing or any sinking or displacement of total anode plates and repair them.

2. Check for any splitting, sealingoff or deformation on the anode plates and repair them.

3. Check the fixing pin roll of the lower cleat of the anode plates, buckle bushing and fixed-position welding; check for any splitting around electrode plate tightened by the buckle bushing. Check the anode plates for any deformation or sealingoff.

4. Check the heat expansion clearance between the lower anode plates and ash hopper port for any seizing, expansion or other resisting sign.

5. There should be no obvious convex-concave on the whole anode plate by visual inspection. Replace them in case of the thickness of the anode plate is less than 50%.

1. Buckle bushing is not loose; surrounding electrode plates are not split; abrasion of hanger is less than 1/3 of original thickness. Total sinking of anode plates is less than 5mm.

2. No splitting or sealingoff occurs on the connecting belt.

3. Buckle bushing is not loose; surrounding electrode plates are not split; rapping rod is fixed in the rail with a transverse clearance of about 4mm.

4. Heat expansion clearance should be calculated as per twice of the value when temperature of the flue reaches the high limit. However, it should not be less than 25mm. the two side of the comb-shaped port should be smooth without steps.

5. bending of plane should be less than 10mm; difference between two diagonal lines should be less than 10 mm.

(III) Detection of the distance between the same electrode of the anode plates

Take the straight electrode plates in the middle of the electric field as reference, measure the distance between the same electrodes. Measurement should be carried out on three points along the height of the electrode plate. ,

Measure and record as per clauses specified in the GB/ T13931-92 [ESP performance test procedure].

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(IV)Calibration of the distance between the same electrode

When the distance between the same electrodes exceeds the specified limit, calibrate the deformed electrode plates. Do not knock the surface of the electrode plate if calibration is not available, replace whole electrode plates.

Each electrode plate should be tested as per manufacturer standard test before replacement. Assemble the plates as per the former sequence and check their straightness.

Allowance error of the distance between the same electrodes is ± 10mm. if the deformation of electrode plates significantly affects ESP’s efficiency, replace all plates.


(I) Maintenance of tube-shaped spine wires

l. check spine passivation, balling and dropping off; check spine wires for any loosing or dropping off; combining the check of distance of two different electrodes, check the bending of the spine wires; tighten, repair, correct or replace them as required.

2. replace the spine wires :

(1) Visually inspect the new spine wires; it should be plain without any twist. Arrangement of spines matches the electrode wire.

(2) During installation, tighten and weld the connecting bolt on upper cathode wire. The blot on the lower part should be loose a half circle after fully tightening before welding.

Arrangement of spines satisfies the requirements of manufacturer; the space error between points is no larger than 1mm; center of the spine wires should match the pipe center of cathode small frame.

(II) Detection and adjustment of the distance of two different electrodes

1detection of distance of two different electrodes should be carried out after the maintenance of large/small frame and the distance between the same electrodes of the anode plate meets requirements.

2. During detection of distance of two

Error of distance between the same electrodes is no greater than 10mm.

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different electrodes, record forms should be prepared including electric field name, passage number, detecting point’s number, cathode wire number, staff, time and results.

3 there are two method for detecting distance of two different electrodes:

(1) Visual observation plus pin gauge. This method can be performed by experienced staff. By visual observation , find out suspect passage and check it with pin gauge. If the pin gauge passes through, the distance of two different electrodes meet requirements.

(2) Standard method. Perform as per GB/T 13931- 92 [ESP performance test procedure] .

Normally two methods are combined, ensuring passage distance of two different electrodes meet requirements. Record the actual distance of two different electrodes of the typical passages.

4. Correction of the distance of two different electrodes: for the electric field where correction for distance between the same electrode and large/small frame and electrode wire as per standards, it can ensure the distance of two different electrodes within a standard range. However, standard may be not fully satisfied because of large work load, short work period and lack of maintenance method and equipment aging. Partial adjustment should be carried out to ensure all distance of two different electrodes within limit. Spine wires can be adjusted by changing the deflection of spine and distance between two sharp points. The number of the adjusted parts should be less than 5% of total to avoid the changing of the discharge center, which effect the

Refer to standard GB/T 13931- 92.

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discharge performance of the electric field.

6.3.2 Cathode, anode rapping unit maintenance


(I) Integrity check of Rapping mechanism

1. Combining with anode plate ash accumulation check, check the anode plates with serious ash accumulation.

2. Check and repair parts based on the protective action of motor overload during operation of rapping mechanism and damage of drive connecting part.

3. Check and treat all fastening parts in the path of rapping force and retaining welding.

1. During normal shutdown, there should be a thin layer of ash on the electrode plat.

2. Under normal conditions, rapping mechanism can be turned manually without motor overload trip.

(II)Rapping drive mechanism maintenance

1. Drive connecting parts maintenance: check rapping universal coupling, flange, and spring gasket for any loose or rupture, and replace and weld them in case of defects. Pay attention to the expansion clearance of the coupling connection.

2. Maintenance of rapping drive shaft: check shaft sections for any twist and whether the coaxiality meets the requirements. For a certain deflection, it can be adjusted by changing the shim of the rapping bearing seat.

Replace the shaft with a over abrasion.

3. Maintenance of rapping bearing:

(1) Check and treat the center variation, sealingoff and displacement of the 4 rapping bearing supports.

(2) Check abrasion of the sleeve. Replace it in case of rupture or over abrasion.

(3) Check the rolling and seizing of the small roller of the bearing. Replace it

Requirement on the coaxiality is that the space tolerance between two bearings is 1mm, total length of the shaft is 3m. the abrasion of the shaft should be less than 4mm.

Sleeve abrasion is less than 1/3 of the former thickness.

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when repair is not available.

(III) Maintenance of rapping hammer and rapping striking anvil

1. Maintenance of rapping hammer:

(1) Check the connection of the rapping hammer head jib, hammer beam and hammerhead; check the fastening parts for any loose, sealingoff, or damage. Repair or replace the rapping hammer shaking seriously.

(2) Check rapping shaft and its connection. Correct and treat the deflection based on the deflection of the hammer point.

(3) Check abrasion and rupture of the hammer. Replace the hammer with rupture or over abrasion.

(4). manually turn the hammers and it should be rotates freely without seizing or collision. Pay attention to the direction of the hammer when replacing hammer with installation direction.

2．maintenance of striking anvil:

(1) Check striking anvil for any loose or sealingoff.

(2) Check striking surface and repair the depressed part to ensure line contact between hammer anvils; replace the striking anvil which can not be repaired.

(3) Check the contacting of the hammer and anvil. The hammer center value in hot state can be observed via hammer marks. For check in cold state, electrode plate expansion should be taken into consideration. The hammer strikes the anvil surface when it drops freely to the vertical position.

Position error of the actual hammer point should be less than 5mm; the contact line between hammer and anvil should be longer than 2/3 of the total length of fully contacting. Considering the heat expansion, hammer point in cold state is 5mm below the center line. The distance error to the anvil surface is ≤ 5mm when the hammerhead freely drops to vertical position.

(IV) Maintenance of cycloidal-pin

1. Disconnect the cable of the motor and clean the reducer casing and seat platform; dismount the chain cover to

a) Pin roll and pin bush are free of bending or deformation, the abrasion

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wheel reducer remove the chain.

2. Disconnect the coupling to remove the motor and coupling.

3. Mark on the contacting surface of reducer casing.

4. Make marks when dismounting connecting rod of the universal joint and proper contacting surface. Notice the thickness of the former paper gasket of the contacting surface. Recover the unit as per former paper thickness and marked position.

5. When remove cycloidal gear “A” (marked on the gear), the mark “A” on the end surface of balance wheel should match the mark “B” on the other cycloidal gear. Recover it as per former relative position.

6. Collision should be avoided when remove rings. When remove and install the roller bearing on the eccentric locking collar, support the bearing together with the eccentric locking collar by hands to remove it along the shaft.

7. When clean runner axle, gear sleeve and gear casing, check related abrasion and clearance. Verify the length of runner axle; seal ring of oil-proof rubber and its spring are all in proper conditions. Otherwise, replace them. Lake-shaped seal ring should be filled with grease. Fill lube oil into the tank until required oil level and verify the oil level gauge is qualified.

8. Maintenance the bearing as per regular procedures. Bearing is normally installed in hot state with a certain stress after installation.

9. When insert input shaft pin into

should be no greater than 0.05mm.

b) Cycloid gear is free of crackle with an abrasion no greater than 0.10mm; pinwheel and pin gear sleeve should be free of bending with an abrasion no greater than 0.10mm.

c) Bearing inner and outer rings and rolling element should be free of crackle or pocking mark. Replace it when the clearance exceeds limit.

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cycloidal gear, the clearance in relative holes should be paid attention to. Do not crash the spacer ring when position with pin sleeve.

10. After assembly, manually turn the high speed input shaft to check for any abrasion.

(V) Test run of anode rapping system

1. When rapping system is reset, manually turning the gear to check rapping rotation and rapping points.

2. Electrically test run for 1h.

1. Turning gear is free of seizing, fluctuation and abnormal noise; the oil mark is clear and the oil level is proper.

2. Reducer is free of oil leakage, temperature rise of the bearing is less than 50K; there is no motor overload. Sound and vibration of the motor and reducer are correct.

Cathode rapping system

maintenance item workmanship and precautions Quality standard

(I) Integrity check of the rapping mechanism

Integrity check mainly focuses on anode rapping except ash accumulation check of the cathode wire.

(II) Maintenance of rapping drive mechanism

1. maintenance of the drive connecting parts:

(1) Check rapping universal coupling or dowel pin coupling, flange, connecting bolt, spring washer for any loose or rupture. Fasten, replace and weld them if necessary. Pay attention to the expansion clearance of coupling.

(2) Check engagement of the drive plate for any over abrasion or damage which affect the normal turning.

(3) Clean the ash accumulation on electric porcelain shaft l’ with a soft cloth. Check for any crackle and discharge.

Electric porcelain shaft should have a vertical moving (expansion ) clearance, which is 10mm normally.

HV test standard for electric porcelain shaft is the same as that for porcelain sleeve. error between the rotating shaft and center of the soldering cup is ≤5mm

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Replace damaged electric porcelain shaft. Visual inspection and voltage withstanding test should be performed before replacement.

(4) Check the contact sealing between drive shaft and casing; verify the center lines of the drive shaft and dust shield match; check the soldering cup for any rust and remove it if necessary.

2. Sliding bearing : maintenance content is the same as that of anode rapping.

(III) Maintenance of cathode rapping hammer and rapping striking anvil

Maintenance content is the same as that of anode rapping.

(IV) Cathode rapping reducer maintenance

Maintenance content is the same as that of anode rapping.

(V) Cathode rapping system test run

Test run content is the same as that of anode rapping.

6.3.3 Maintenance of cathode suspension device and large/small frame


(I) bushing suspension device

1. Visual inspection and maintenance :

(1) Wipe the surface of the support porcelain sleeve with a soft cloth. Check surface and support stress surface for any mechanical damage, insulation damage or discharge vestige.

(2) Check suspender and locknut, load bearing parts for any mechanical damage.

(3) Check corrosion of soldering cup and the coaxiality of suspender and soldering cup; remove the dust and rust inside soldering cup.

1. Concentricity error between soldering cup and suspender is no greater than 5mm.

Manhole is airtight and has been check; inside should be cleaned.

2. HV test standard of porcelain sleeve should be 1.5 times of the rated voltage of the electric field. It should not be broken through within 1min.

elevation error of the

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(4) Check the electrical connection between HV suspension device and HV switch cabinet wall bushing.

(5) Check sealing of the manhole.

2. Replace support porcelain bushing: replace damaged porcelain bushing. Before replacement, mark the fixed position of the suspender bolt. Provide temporary measures to keep the balance of four supporting points to avoid damage to porcelain sleeve new porcelain sleeve is intact by visual inspection; HV test is acceptable; elevation error of the porcelain sleeve in the same group ( totally four) meets requirements.

porcelain bushings in the same group should be ≤ 1mm.

(II) Cathode large frame maintenance

1. Check the levelness and verticality of the cathode large frame meet the design requirements or not.

2. Check and repair the partial deformation, sealingoff or splitting of the large frame.

3. Check stairs on the large frame for any loose or sealingoff and repair them.

Flatness error of the frame is not greater than 15mm, diagonal error≤10mm. cathode large frame should be vertical to the horizontal plane with a verticality error ≤ 10mm and elevation error ≤2mm.

(III) Cathode small frame maintenance

1. Check the connection of the upper and lower small frames and fixation of the small frames on the large frame. Correct, repair and weld in case of bending, deformation or sealingoff.

2. Check plainness of the small frame and correct it as required.

3. Calibration of small frame plainness should be combined with the distance of two different electrodes to ensure the distance of two different electrodes within specified limit.

Plainness error of the installed and welded cathode small frame is ≤10mm and the diagonal error is ≤5mm. all nuts and bolts for small frame should be welded for retaining. There should be no burr on the welding position.

6.3.4 Maintenance of other auxiliaries of ESP

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maintenance item workmanship and precautions Quality standard

(I) ESP casing maintenance

1. Check casing for any abrasion and air leakage. Patching should be carried out for abrasion and corrosion.

2. Check support pipe and lacing wire in casing. Replace seriously worn parts.

3. Correct the deformation of the inner wall of the casing and baffle.

Air leakage ratio of the ESP is lower than 3%.

(II) Inlet smoke chamber maintenance

1 deflector before inlet smoke chamber:

(1) Check abrasion of the deflector and support parts. Replace the seriously worn parts. Anti-abrasion measures should be provided for part used less than an overhaul period.

(2) Check the arrangement of deflector is in accordance with the former design; carry out treatments like adjustment and repair welding.

2. Inlet smoke chamber :

(1) Check and repair the abrasion and corrosion of smoke chamber inner wall and support as well as lacing wire. Replace seriously worn parts. Anti-abrasion measures should be provided for part used less than an overhaul period

(2) Repair and strengthen the depressed position of the smoke chamber.

(3) Check air leakage of contacting surface between the flange of the casing and inlet smoke chamber. Replace packing material if necessary.

(III) Maintenance of grid plate

1. Check the abrasion of the support pipe, angel steel and connecting bolts for supporting and fixing air flow grid plate. Replace the seriously worn parts.

2. Check abrasion of the air flow grid

When the abrasion volume reaches 1/4 of the former opening, or it has obviously effect the efficiency of dedusting, replace it.

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plate. Repair seriously worn part. Take anti-abrasion treatment if necessary. Find out the cause of over abrasion and eliminate it, for example, to adjust the inlet deflector. When abrasion of the whole unit reaches a certain degree, replace it.

3. During replacement of the air flow grid plate, the design requirement should be satisfied. Determine whether to replace or how to replace by air flow distribution test.

Test and criteria as well as standard refer to GB/T1393-92 [ESP Performance Test Procedure].

(IV) Maintenance of ESP top

1. Check and repair any abrasion, corrosion or air leakage on the ESP top.

2. Check rainwater collecting annulus and downcomer.

(V) Outside insulation and frame cover maintenance

1. Check outside insulation and frame cover for any falling off or damage and carry out treatment.

2. Check the corrosion and fixation of the outer frame cover. Measure should be take for any loose or abrasion.

3. Water flow direction should be taken into consideration when lap the new plates to the old plates and the lapping seams should be straight.

Outer insulation and frame cover should be plain, firm, orderly, rain-tight and anti-gale after maintenance.

(VI) Outlet smoke chamber maintenance

1. Maintenance of the outlet smoke chamber refers to that of inlet smoke chamber maintenance.

2 maintenance of the trough plate:

1) Check abrasion and deformation of the trough plate and correct them.

2) Check and reinforce the support, suspension and arrangement of the trough plate.

3) Trough plate rapping mechanism

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maintenance refers to anode rapping.

(VII) Maintenance of manhole

1. The opening and closing of the manhole is free and airtight without air leakage (check it based on the air leakage during equipment operation), replace disable packing seal and corrosion, damaged bolt and nut.

2. Check corrosion of the inner wall of the manhole and carry out rescaling and repairing.

3. Check safety signs on the manhole, which should be complete.

The opening and closing of the manhole is free with complete safety signs without air leakage.

6.3.5 ESP ash hopper and slide damper


Maintenance of ash hopper and slide damper

1. Check corrosion of flange contacting surface of the ash hopper based on the leakage and corrosion during operation. Repair as required and grind the welding points with sand grinder.

2. Check the arch plate on ash hopper for any sealingoff with the side wall. The surface should be smooth and flat without scar after repair welding.

3. Check the abrasion and fixation of the supports in ash hopper and hanging beam of the air baffle of ash hopper. Repair, correct and weld any displacement.

4. Check abrasion, deformation and loose of the air baffle in ash hopper; check abrasion of the lug and suspension ring of the turning parts of air baffle; repair and replace as required.

5. Maintenance of the slide damper at the bottom of ash hopper: replace gland packing at slide damper and ash hopper flange to eliminate the ash leaking points at contacting surface. Check the

Inner wall of the ash hopper is free of leakage and cicatricle, which may catch ash.

Corners in ash hopper are smooth without dead angle.

Ash hopper is free of deformation and the supports structure is secured.

Air baffle is free of loose and inclination. Replace the hanging ring if the abrasion volume is greater than1/3 of its body.

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operation of the slide plate mechanism for any seizing; adjust them and remove rust as well as add lube oil.

6. Ash hopper gasification unit maintenance:

(1) Check gasification pipe line and gasification electric heater.

(2) Check abrasion and blockage of the ash hopper gasification plate and replace them when manufacturer limit is exceeded.

Valves should be opened and closed freely and can be reliably isolated without leakage.

Stairs, platform , rail maintenance

1. Check all platforms, passages, stairs and rails inside and outside ESP; repair and replace those damaged or not conform to safety regulations.

2. Remove rust of outdoors steel structure, such as platform, passage, stairs, rail, reducer casing and paint.

There should be no crackle or corrosion; the footpath on platform is straight and flat. Strength meets requirements.

6.4 Tests after ESP maintenance

6.4.1 Prerequisite for acceptance test

1. Tests and commissioning on the ESP HV/LP electrical equipment have completed.

2. ESP mechanical maintenance has completed and test of turning equipment have finished.

6.4.2 Acceptance test items

It is to verify the maintenance quality of ESP mechanical parts and electrical parts and ESP performance.

Cold state acceptance and test

1. Spot-check of distance of two different electrodes:

(1) Record the distance of two different electrodes detect during maintenance. spot-check and review 5%~10% of them.

(2) Select 1 or 2 passages which are recorded to detect the distance of two different electrodes. The result should be in accordance with the requirement on distance of two different electrodes. Repair and detect the electric field which fails to meet the requirements.

2. Air flow distribution test: for ESP passed model test with a similar condition with tested equipment, air flow distribution test will not be performed during overhaul. Air flow distribution

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test can be carried out in one of the following cases:

(1) Air flow grid plate is over worn; it is needed to or has significantly adjusted or replaced the inlet deflector and air flow grid plate.

(2) Dedusting efficiency drops significantly and operation condition of ESP changes significantly; the air flow uniformity is doubted to meet requirement.

Air flow distribution test refers to GB/T13931-92 [ESP Performance Test Procedure]. If the test results can not meet the standard, calculate and adjust again until requirements are satisfied.

3) Rapping acceleration test: when serious ash accumulation exists on the electrode wire and electrode plate, rapping acceleration test should be considered to be performed. Test should be carried out as per GB/T 13931-92. When design requirements of manufacturer can not be satisfied, cause should be found out and treated.

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7. Double screw rod air compressor(zrseries)

7. 1 Double screw rod air compressor technical specifications

ATLAS COPCO fixed type air compressorzr series is a kind of oil spout double screw rod air compressor. This type of air compressor is of the following advantages ,such as, structure is simple, can be operated easily, the number of wearing parts is few, changing spare parts is easy and function is Stable and reliable. Therefore it is widely used in many related industries.

7. 2 Double screw air compressor structure

ZR110 to ZR750 air compressors are oil-jet twin screw stem types with two stages compressing and driven by motor. They can provide air with stable pressure. Water cooling is adopted. For this kind of air compressor, their structure and operation principle are nearly the same although there are some differences in details. Air compressor is installed in a noise enclosure including the following parts:

air filter

-LP screw stem head

-intermediate cooler

-hpscrew stem head

aftercooler

motor

Driving coupling

Gear box

-Elektronikon. Control system

Safety valve

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Front elevation of ZR series air compressor

AF. Air filter

AO. Air outlet

Ca. Aftercooler

Co. Oil cooler

CM. Elektronikon PC controller

Daa. Automatic condensate blowdown port of aftercooler

Dai. Automatic condensate blowdown port of Intermediate cooler

Dma. Installation port for condensate manual blowdown valve of aftercooler

Dmi. Installation port for condensate manual blowdown valve of intermediate cooler

Dra. Aftercooler condensate blowdown tank

Dri. Intermediate cooler condensate blowdown tank

Eh. Hpscrew stem head

El. Lpscrew stem head

M1. Main motor

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Svh. Hpsafety valve

Svl. Lpsafety valve

TV. Full load/no-load valve

WI. Cooling water inlet

WO. Cooling water outlet

1. Direction of motor rotation

2. Flange

3. Maintenance hole for air filter

4. Regeneration air pipe with non return valve

Side elevation of ZR series air compressor

AF. Air filter

AO. Air outlet

Ca. Aftercooler

Ci. Intermediate cooler

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DP2/5. Blowdown plug screw (painted green)

Dra. Aftercooler condensate blowdown tank

Dri. Intermediate cooler condensate blowdown tank

Eh. HP screw stem head

El. LP screw stem head

M1. Main motor

Svh. HP relieve valve

Svl. LP relieve valve

TV. Full load/no-load valve

WI. Cooling water inlet

WO. Cooling water outlet

Y1. Loading solenoid valve

1. Direction of motor rotation

2. Flange

3. MD dryer joint

4. Cap

1. Drive system: includes main motor, coupling, gear box etc. Normally, the application of coupling is ignored for minor units. For medium or large units, separable coupling drivers will be installed for easy assembling and maintenance.

2. Major equipment: in the ∞ shape casing, two engaged screw stem rotors are arranged parallelly, respectively called female and male rotor. Two rotors form a pair of enclosed V type space with casing. This space will reduce along with the rotation of rotor and the space will move towards primary port from intake port. This is the whole process of intake- compress - primary.

3. Control system includes induction system, governor system, minimum pressure valve bank, safety control system and PC controller. Subsystems all contain associated solenoid valves, sensors, air-operating piping and related PC programs and orders.

Control system contains the most parts and acts most frequent. Therefore, it is the system with the most failures. The largest differences and features of different brands are reflected by this system. In consideration of high reliability, quantity of parts in the ATLAS unit is reduced as far as possible. Even the governing system is cancelled. Therefore, ATLAS unit has a simple operation method. In addition, ATLAS combines the load controlling system and discharge system to the air intake valve. Failure ratio is reduced significantly by adopting piston valve instead of adjustable butterfly-valve. Its simple operation method makes it difficult for user of

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small amount of air to match demand and supply.

4. Cooling lubrication system: includes special lube oil, heat exchanger, temperature- sensing valve, oil cut-off valve and cooling fan.

5. Air flow-oil system-cooling system: air is sucked into LP head (E1) through air filter; after compression, compressed air enters intermediate cooler (Ci) to be cooled. Then compressed air enters HP head for further compression. Before enters air network, it flows through silencer (AS) to reduce noise and aftercooler to be cooled. A check valve (CV) is also installed at the downstream of silencer for ZR110-275 and downstream of aftercooler for ZR300-750.

6. Condensate blowdown system: two Water separators are installed. One is installed at the down stream of intermediate cooler (mti) to prevent condensate from entering HP screw stem head. The other is installed at the down stream of aftercooler to prevent condensate from entering primary air pipe. Water separator is connected to the condensate blow down tank. Each blow down tank is equipped with a ball float valve for automatic blowdown and a manual blowdown valve. For ZR300-750, an extra water separator is installed on the vent pipe preventing condensate from entering silencer when equipment transfers from loading to unloading.

7. Lube oil system: lube oil in the oil sink of gear box is pumped by the oil pump (OP) to bearing and synchronizing gear through cooler (Co) oil filter (OF). Bypass valve (BV) will open when pressure of lube oil reaches the setting valve.

Cooling system: cooling water flows by cooler (CO) to the cooling water jackets of HP screw stem head (Eh) and LP screw stem head (El) respectively. For ZR300-750 type, cooling water is also used to cool the vent pipe of LP screw stem head (E1) and flows by Intermediate cooler (Ci) and aftercooler (Ca). Cooling system parts failure will directly result in outage of unit. More than 90% of heat exchanging is carried by cooling system. During hot days, volume of exchanged heat will increase several times. Any improper maintenance of the cooling system will result in poor operation, low efficiency, high energy consumption etc. It is important to perform preventive maintenance before hot days.

7. 3 Maintenance level for Double screw air compressor

The maintenance level of the air system is determined by the oil service life, action times of parts, bearing service life and abrasion situation of parts..

Normally, the quality and performance of the mineral oil will significantly decrease after 2000 hours operation, and the accumulated carbon will increase. After 2000 hours operation, the meshes of the filter adopting paper element will be seriously blocked causing the filtering efficincy decrease, pressure of the lube oil decrease and the inactive power of the unit increase. The service life of the oil used for filter with glass fibre as element will reach more than 4000 hours. In addition, the service life of the sealing rings of the moving parts in the minimum pressure valve, load controlling valve of the control system might reach 4000hours because of iron-oxygen used in the sealing ring. Normally, service life of the air compressor is about 8000

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hours. The maintenance can be divided into three levels: A, B and C corresponding to 2000,4000 and 8000 hours. At the above said time and their times, maintenace should be carried out to prevent accident. Details include:

Quarterly: level A: oil, oil filter, air filter

Half a year: Level B: Level A plus oil conten as well as maintenance packages of control system.

Yearly Level C: Level B plus temperature control valve, loading solenoid valve, oil pressure control valve and operation of motors.

After several years’operation, dynamic balance and strength of resonance of the air compressor should be tested to provide data for overhaul of the main machines and driving system.

. 4 Level C maintenance for double screw rod air compressor

7.4.1 maintenance preparation:

Start the equpment to run for 15minutes; estamite the operation situation of the equipment via primary observation so as to determiine the keypoints of maintenance activity and to increase lube oil temperature and decrease its viscosity.

Verify operating parameters of the unit by PC controller for comparision with data after maintenance;

Shutdown procedure: close outlet valve, cut off the power supply of the unit and push emergency shutdown button;

Open manual blowdown valve, vent down the pressure of the primary pipe; verify pressure of entire unit and close the waterinlet/outlet valve.

Site preparation: level C maintenance will break down all system parts except main machines and replace all oil. Therefore, the worinf area should be treated to avoid pollution and be good to clean site.

7.4. 2 Dismantling of unit system parts:

Turn loose by wrench the oil drain hole screws of the oil and gas bucket, oil filter seat, mian primary pipe,oil cooler, oil cut-off valve and gear box; when completely empty lube oil and vent the oil cutoff valve and main primary pipe, plain screw driver should be used to drive clockwise the machine from the motor rod wheel to ensure lube oil in the main machine and gear box is completely drained out. Waste oil should be treated intensively to avoid pollutions.

Manually take off the set screws (8) at the ends of main primary pipe between the oil and gas bucket cap and cooler; check two sides of the sealing ring and store them caerfully.

Remove by wrench the connecting hoses of pressure difference transmitter, drain pipe, main control hoses, oil return hoses, main oil return pipe and HP oil pipe before and after cooler.

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Remove by wrench the set screws (6) of the minimum pressure valve and remove minimum pressure valve and lower check valve.

Remove set screws on the oil separator cap with wrench, after remove all screws, tighten screws on the cap side and completely separate the cap from the oil and gas bucket and turn it in clockwise direction to the final position. Take out oil content element and upper/lower sealing rings and well store them.

Loose set screws (4) of the “oil pressure ontrol valve+temperature control valve” with allen wrench to take off oil pressure regulator; then take pout the disc of temperature control valve and well store them.

Remove oil filter(3) with chain wrench.

Remove set screws (8)oil cut valve with wrench, and take off oil cut off valve assembly(2).

Remove set screws (8) of air inlet valve wrench and take off air inlet valve assembly(2).

Loose holding screws (2) of the air filter and take out air filter element(2).

7.4.3 Dismantling of minimum pressure valve, oil cutoff valve, air inlet valve and oil pressure regulator

1. Dismantle minimum pressure valve assembly: loose set screws of the minimum pressure valve cap, and take out reset spring; slightly knock the piston from outside to inside to let it fall down automatically. Pry out sealing ring with plain screw driver. Remove set screws (3 ) of the check valve packing seal and take off packing seal and triangle gasket. All parts should be well stored

Dismantle oil cutoff valve assembly: remove inner snap ring with inner snap ring pliers. Take out piston and reset spring. Remove set screws (4) of the lower end cover with wrench and take off the end cover. Take out piston. All parts should be well stored.

Dismantle oil pressure valve regulator assembly: loose the seat and set screws of the oil pressure regulator with allen wrench to take out piston

Dismantle air inlet valve assembly: remove set screws (4) of the end cover of air inlet valve with wrench to take out reset spring. Knovk the piston from outside to inside until it drops naturally pry out the sealing ring of piston and take out the snap ring of the end cover of load controlling valve with inner snap ring pliers. Clamp the end of the end cover with lock wrench. Pull out end cover by slightly turning it. Then take out reset spring. Pull out load controlling piston with vise.

Dismantling of all parts are completed up till now.

7.4.4 Check, verify, repair, replace system parts

In turn check sealing ring of parts.

In turn check operation of pistons of parts.

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In turn check abrasion of wearing auxiliary parts.

In turn check aging of all hoses

Verify the above check activities. Replace the entire maintenance package containing parts needed to be replaced and record the results.

7.4.5 washaftercooler:

Remove holding screws of the water inlet and outlet chuck of the aftercooler with wrench. Take out chuck. Lift the entire aftercooler to a specified location.

Marinate the water pipes and oil pipes with scale washing agent and carbon washing agent for 6 hours, nd flush with clean water. Determine whether to marinate the pipe based on the washing result.

7.4.6 Check sensors

Check all wire connecting terminals inside the electric cabinet and the strength of the connecting wires.

Check ablation of main contactor.

7.4.7 Recover

Recover chucks of cooler and water pipe.

Recover the system parts according to the turns of parts, assembly and system which is opposite to the dismantling of the system

7.4.8 Startup commissioning:

Check and verify all hosesconnection, tightness of all holding screws;

Open outlet valve to test pressure; the minimum pressure valve is free of leakage;

Open cooling water valve and no leakage is detected;

All screws of the oil drain holes, fill cooling oil to the specified level and then tighten the oil filling screw;

The unit and reset all maintenance parameters;

Unit without abnormal condition; load the unit without abnormal condition;

Unit, fill oil to the level of oil filling port and tighten the oil filling screw;

The unit and load; verify all operataing parameters meet the requirements

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8 Oil Free Screw Air Compressor

8.1 Technical Specifications

To supply clean compressed air, the motors supply no lubrication and cooling to the compressing part of the main rotor. The motors adopt two stage compressions, two stage cooling and two stage gas water separation to lower the work temperature to an acceptable level. The rotors are made of special materials with advanced technology to lower the motor load. All the above is to make the air compressor adapt to harsh work conditions. However, the parts with no compressed air contact, including gear box and bearings, are still oil lubricated and cooled.

8.2 Oil Free Screw Air Compressor Configuration

The compressor consists of driving system, two stage air intake valve, low pressure motor, high pressure motor, gas water separator, cooling system, lubrication system and electronic control system.

As the compressor has twin motors, the driving system and working principle is different from those with single motor.

When the compressor starts, it drives the specialized gear box through coupling, which at the same time drives the twin motors and oil pump to pump the oil from the gear box. In order to prevent oil leak to the rotor from the motor casing when the pressure is high, the oil system has a by-pass valve, which opens automatically to release the pressure. When the compressor reaches the nominal speed, the solenoid valve is triggered. The primary airintake valve gradually opens under the system pressure to start the primary motor. The primary motor works and the compressed air enters the middle cooler. With pressure increasing, the high pressure air overpowers pressure relief valve to completely open the airintake valve, followed by pressure increase and primary gas water separator to enter the secondary air intake valve silencer to open the minimum pressure valve to go to the secondary motor for further compression. The high temperature and pressure gas is supplied after secondary oil gas separator and cooling. When the secondary pressure reaches relief pressure, the loading solenoid valve is cut off and turned off to release the valve and the pressure is released with primary airintake valve closed and secondary airintake valve returned, the motor starts unloading. Simultaneously, the oil from the oil pump is supplied to the dual motors and gears after filtering and the oil returned is collected by the gear box after oil cooler and the balanced between the oil and the atmosphere is maintained through breather.

If the unloading is too long, the controller will stop the compressor until the pressure drops to loading pressure to initiate another cycle.

8.3 Maintenance and Service

1. It shall be carried out by professionals.

2. Daily monitors the operational parameters.

3. Weekly cleans the motors.

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4. Monthly monitoring of the oil consumption.

5. Cleans or replaces the air filter and oil filter every 2000 hours.

6. Cleans middle cooler, rear cooler, oil cooler, oil breather, gas oil separator every 4000 hours and carry out motor lubrication.

7. Replaces lubrication oil every 8000 hours.

8. Overhual the motors every 16000 to 20000 hours.

Content:

1) Above 1 to 7.

2) Examine and replace main motor bearings.

3) Examine and replace motor bearings of fan.

4) Replace gear box bearing.

5) Observe oil pump and by pass valve.

6) Examine main motor.

8.4 Commissioning

1. Check all the pipes are well connected, nuts tightened.

2. Open the outlet valve to test the pressure and make sure there is no leakage from the minimum pressure valve.

3. Power supply to the motors and reset all the service parameters;

4. Start the compressor with no abnormities noticed and loading goes well;

5. Restart the compressor and load to ensure all the parameters are in compliance to the requirements.

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9 Refrigerated Air Dryer

9.1 RSL Type Refrigerated Air Dryer Technical Specifications

9.1.1 Working Principle Description

RSL Type refrigerated air dryer lowers the air temperature so that the water vapor in the compressed air become over-saturated and turns into water droplets, which will be separated and discharged, so that the compressed air can be dried. The dew point of the compressed air in the RSL dryer can be lowered to 2~10 under pressure. ℃

RSL Type refrigerated air dryer product is as a result of several new technical innovations and patents, characterized by its stability, efficiency, cost-effectiveness and automation.

9.1.2 Refer to Figure 1 for the work procedure of the refrigerated air dryer.

YS3

测点P，T测点P，T

YS1

空气出口

空气进口

YS2

R

S1

R3

YS1

R

KP15

冷媒低压冷媒高压

12

56

8

3

210

911

1

R5

DN15

DN15

测点T

R5

测点T

测点T

测点T

测点T

YS2

DN15DN15

X1

7

D2

4

D1

Figure 1 Work Principle of the Refrigerated Air Dryer

1. Pre-cooler 2. Evaporator

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3. Cyclone Separator 4 Automatic Water Capacity Adjustment Valve Discharge Equipment

5. Refrigeration Compressor 6. Condenser

7. Water Regulating Valve 8. Drying and Filtering Device

9. Stop Valve 10. Expansion Valve

11. Capacity Adjustment Valve 12. High/Low Pressure Controller

9.1.3 Process Description

Air Compression

1. Air compression consists of pre cooler, evaporator, cyclone separator, and automatic water discharge equipment.

2. The humid compressed air from the air compressor enters the pre cooler of the refrigerated air dryer, where it conducts heat exchange with the low temperature compressed air from the cyclone separator and becomes cooler. As a result, it is condensed due to over saturation together with oil and dust particles.

3. The pre-cooled compressed air enters the evaporator to carry out a further strong heat exchange, when the temperature is dramatically dropped to the dew point to produce large quantity of water, which will then be drained together with that in the pre cooler by the automatic water discharge system.

4. Then, the low temperature compressed air enters the cyclone separator, where the condensed water particles is separated by enforced cyclone and discharged. By now, the compressed air reaches the drying requirements.

5. The dried low temperature compressed air returns to the pre cooler to heat exchange with the humid high temperature air, which is then to be conveyed downstream for use.

Refrigeration System

1. The refrigeration system mainly consists of air compressor, condenser, expansion valve and evaporator with other auxiliary parts.

2. The refrigerant is compressed by the refrigeration compressor into high temperature and pressure gas and output into condenser, where it is cooled into liquid with normal temperature and pressure. Then it goes to expansion valve and expands and changes into low temperature and pressure gas liquid mixture and enters the evaporator to heat exchange with the compressed air. The refrigerant mixture absorbs the heat from the incoming compressed air and evaporates and is sucked into the refrigeration compressor to reinitiate the cycle.

3. The hot air bypass valve is to control the amount of refrigerant to be recycled based on the load change of the compressed air so that refrigeration system matches to the load of the compressed air to ensure the quality of the air. The valve requires manual

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adjustment when the load varies greatly.

4. The high/low pressure controller is to ensure the refrigeration compressor work within the specified scope. The condensation controller is to ensure the condensation pressure not lower than specifications. Both the scope and the condensation pressure have been factory pre-set.

5. The drying and filtering device plays the role of cleaner, to remove the water, impurities, and acid matters in the refrigerant.

6. The water regulating valve is to control the water supply based on the primary pressure of the refrigeration compressor to maintain the normal condensation pressure. The valve requires manual adjustment when the compressed air load varies greatly or the temperature and pressure of the cooling water varies dramatically.

7. Refrigerant valve is to fill in refrigerant when the dryer is being assembled or serviced.

8. The solenoid valve is to cut off the high and low pressure parts of the refrigeration system when the dryer stops, so a balance between them can be gradually achieved.

9. The stop valve is for maintenance and service.

9.2 Maintenance and Service

9.2.1 Principles

1. The dryer has to be enlisted for company assets management, and the maintenance, service and operation log regulations need to be set up based on the characteristics of the dryer and to be strictly implemented.

2. The operation, maintenance and service of the dryer shall be conducted by trained personnel.

3. The dryer in operation needs to be checked regularly, every 1 to 2 hours, and logged.

9.2.2 Content

1. Periodically check the conditions of the dryer to ensure the its good performance. Recommended once weekly.

2. Cleans the automatic water discharge system periodically to remove the accumulated oil and impurities that might affect its normal operation. Recommended once weekly.

3. Clean the blades of the fan condenser once every two weeks to remove the dust and impurities. The procedures is as follows as indicated:

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Note: Care shall be taken in operation not to damage the blades and heat exchanger. Striking from hard objects is prohibited.

9.2.3 RSL Air Dryer Troubleshooting

Table 5 Air Dryer Troubleshooting

Conditions Possible Causes Solutions

Power supply or power fault Check the power switch or the lines

low voltage Check voltage to make sure it complies with requirement

Loose power connection to the electronic control system

Reconnection

Electric trip Check the breaker and thermorelay and

reset. Also examine the voltage and power lines

Delayed start after high/low pressure protection initiates Wait after the delay to start

Refrigeration compressor damage *replace compressor

Refrigerant leakage *Check, and repair the refrigeration system and refill in refrigerant

The dryer does not

start.

Refrigeration compressor start up capacitor damage Replace capacitor

Clogged water drain system Clean, repair or replace

Installation error in automatic water drain system Reinstallation

Humid air from the

dryer outlet

Air by-pass valve not turned off Turn off the by-pass valve

Condenser cleaning of the air-cooled air dryer

IN OUT

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The air dryer does not work Check the air dryer system

The front service valve of the automatic drain system is not turned on

Turn on the front service valve

Refrigeration system faulty *Check or repair the refrigeration system

Poor condensation capacity Clean or dust condenser

Air compressor overload(exceed the rated capacity)

Reduce the capacity or replace air dryer

Compressed airintake temperature too high

Lower airintake temperature or replace air dryer

Compressed airintake pressure too low

Increase airintake pressure or replace air dryer

Cooling water temperature too high Lower cooling water temperature

Amount of cooling water not enough

Adjust water regulating valve or increase water supply

Ambient temperature too high(Wind-cooling type)

Improve site ventilation or replace with a water-cooling air dryer

Hot air by-pass valve opened too wide Reduce the opening

Heat expansion valve opened too small *Increase the heat expansion valve

Refrigerant not enough *Add refrigerant

Refrigerant leakage *Service the refrigeration system

Abnormal dewpoint

Clogged drying and filtering device *Replacement

Clogged or damaged Cleaning or replacing

Service valve not open Open service valve

Float Type Automatic

Water Discharge

system faulty

Installation error Reinstall

Solenoid valve no power Check the cables to supply power

Solenoid coil burnt Replace solenoid coil

Electronic Automatic Discharge

System Faulty Clogged valve Cleaning

Air Dryer Poor condensation Clean condenser

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Air dryer overload Check whether the flowrate, temperature and pressure of the compressed air are within the rated values

Cooling water too hot Lower the temperature of cooling water

Cooling water not enough Adjust water regulating valve to increase water

Ambient temperature too high(air cooling type air dryer)

Improve ventilation or replace with water cooling type air dryer

Condensation motor faulty *replace motor

Clogged cooling system *Check the drying and filtering device and heat expansion valve, either replace or repair

Thermo-sensor of the heat expansion valve faulty *Replace the expansion valve

stops after operation or frequently

trips during operation

Air existing in the refrigeration system *Re-vacuumize and refill in the refrigerant

The voltage exceeds the rated voltage scope

Check the power voltage Electronic protective

switch tripping

Refrigeration compressor overloaded Adjust the air drying system

Poor condensation Clean the condenser

The air dryer overloaded Check whether the flowrate, temperature, temperature and pressure of the compressed air are within the rated scope

Cooling water too hot Lower cooling water temperature

Cooling water not enough Adjust water regulating valve and increase water amount

Ambient temperature too high(air-cooling type air dryer)

Improve ventilation or replace with water cooling type air dryer

Refrigeration

compressor temperature

too high

Refrigerant too little Fill in refrigerant

Frost at the surface of

refrigeration compressor

The air dryer was less loaded

Adjust hot gas by-pass valve or adjust water regulating valve or to adjust the load of the air dryer

The air inlet and outlet valves are not fully open Fully open the valves Pressure

difference too high

between the air inlet and

The amount of compressed air exceeds the rated amount Reduce compressed air amount

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air outlet of the air dryer Evaporator clogged by ice Adjust refrigeration system

Note: the items with asteroid means they shall be handled by professionals by the equipment supplier.

Warning: Specified procedures have to be followed in case of faults to prevent further damage.

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10 Gasification Blower

10.1 Technical Specifications

Type of the blower: SRD-100; Intake flow rate: 11.7m3/min; Inlet pressure : 101.3Kpa，outlet pressure: 199.3Kpa; rotation speed: 1450rpm; motor type: Y225S-4; power: 37KW

10.1.1 Working Principle

SRD-100 Roots blower is a volume type power machine with two impellers rotating in opposite directions driven by a pair of synchronized gears. Through the two impellers gearing with each other (clearance between impellers without contact), the inlet and the primary outlet is divided and the air is transferred to the primary outlet without compression. The air when reaching the primary outlet is compressed to transfer to the system due to the compressed air at the outlet side.

Work Principle Illustration

Chinese English

进气 Inlet

排气 Exhaust

10.1.2 Motor Configuration Diagram

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10.1.2.1 Casing and walling

The casing and walling of the blower is an integrated structure made of high strength cast iron and the casing is horizontal with external side strengthened with bars.

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The walling (with side plates) is installed at both sides of the casing. The side plates functions to position the walling, and with walling and casing together, they form a sealed cylinder.

10.1.2.2 Impellers

The impellers are made of quality cast iron with cycloidal profile. The top of the impellers have wide arch boss, made by specialized lathe. The impellers are fitted to the shaft using heat expansion methods and through dynamic poise to reach an accuracy of G5.6 in the balance.

10.1.2.3 Gears

Gears are one of the most important parts in roots blower, made of quality chrome molybdenum steel, and ground by grinder after carburizing and quenching, with a grade 5 in GB10095.2-2001.

The gears have wide tooth width with good meshing inside the gear box. The deviation caused by wear can be eliminated by the adjustable gear. Please note that the adjustable gear and the hub shall not be separated when dismantling but not in adjustment.

10.1.2.4 Bearings

All bearings are E grade with 4 bearings installed on the bearing seat of the walling, among which the inlet side two bearings performs the role of adjustment and fixing the axial clearance of impellers.

10.1.2.5 Shaft Sealing

The sealing of the shaft adopts labyrinth seal and at the bottom of the 4 bearing seats is fixed with V type seal to further separate the oil and gas. In the shaft gland, the seal adopts rubber structure to prevent oil leakage and dust.

10.1.2.6 Lubrication

The lubrication of the blower integrates splash lubrication and forced circulation lubrication. The gear box and oil box have all got oil gauge with the correct oil level indicated when the machine is not operation. In operation, the oil level shall be within the correct level. If the oil level is too high, the temperature might rise and if too low, the lubrication is not good.

If the blower is used for general purpose, the lubrication oil is mineral oil, such as machine oil, gear oil, hydraulic oil, or anti-rust turbine oil. There shall be no water, carbonate, resin or bar contained in the oil. The oil volume in the gear box shall be 2.4 L and in the standby oil box 1.1 L.

10.1.2.7 Cooling system

Cooling water rate: 8~10l/min; Water pressure: 196~294kPa; Inlet water temperature: Less than 33 .℃

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10.2 Maintenance and service of the blower can be as per the table below.

No. Period of

Inspection

Items

Before Operation

DailyThree

MonthsAnnually

Two

Years

Four Years

Remark

1 Clean the foreign objects in the piping

○

2 Check every connection part

○ ○ Blower, piping

3 Valve operation

○ ○

4 Inverted Valve operation

○

5 Electric circuit ○ ○

6 Gear oil volume

○ ○ Oil gauge

7 Oil leakage ○ ○

8 Rotation direction

○ As indicated

9 Pressure ○ ○ Pressure gauge, vacuum gauge

10 Safety Valve ○ ○

11 Current and Voltage

○ ○ Ammeter, Voltmeter

12 Flowrate ○ ○

13 Noise ○ ○ Gear abnormal noise, rotor

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collision noise

14 Vibration ○ ○

15 Temperature ○ ○ Ambient, blower, and motor

16 Tension and wear of V-belt

○ ○ Adjust if loose and replace if worn

17 Gear and bearing operation

○ ○ Beware of abnormal noise

18 Gear oil replacement

○ Replace all(first replacement after 500 operation hours)

19 V-belt replacement

○

20 Filter cleaning ○

21 Oil seal replacement

○

22 Rotor and casing inside cleaning

○

23 Gear checking

○

10.2.1 Dismantling

1.1 Cautions

1. All the connections and couplings shall be marked.

2. No damage shall be done to the parts especially to the joint surface.

3. All gaskets shall be measured when dismantling.

4. The parts after dismantling shall be kept dust free.

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5. Appropriate dismantling tools shall be used.

1.2 Dismantling Procedure

All the accessories dismantled; discharge the oil in the gear box and standby oil box; dismantle the wheel; dismantle standby oil box; dismantle gear box and gears; dismantle walling.

NOTE: In the operation, care shall be taken to protect the seal and bearing internals.

10.2.2 Assembling

2.1 Cautions

1. Check whether the dismantled parts are damaged. Care shall be taken to the joint surface. When there is damage, repair it or replace.

2. The bearing shall be cleaned first, then greased. When installing, the tools and hand shall be cleaned first.

3. The joint surface shall be cleaned first before greasing.

4. In case of damage of sealant, then the gasket with the same thickness and quality material shall be used.

2.2 Assembling Procedure

1. Install the walling (with side plates) of the motor side to the casing.

2. Install the impellers from the gear side.

3. Install walling (with side plates) at the gear side to the casing. Care shall be taken to the axial clearance. When there is not enough, then, a casing seal can be chosen.

4. Assemble the seal jacket, V shape seal, bearing seat and front and rear bearings. Use the bearing seat gasket to control the axial clearance.

5. Assemble gears. On both sides of the key sprayed molybdenum disulfide (not on the gearing face), use the adjustable gear to adjust the impellers and then tighten them with locknuts.

6. Assemble gear box.

7. Assemble standby oil box. If necessary, the location pin for the standby oil box and walling shall be remade and implemented.

8. Assemble the wheel and other accessories.

2.3 Clearance Adjustment

The key to the blower assembling is to ensure the working clearance within the specified scope so its quality and performance is guaranteed. The clearance scope is as follows:

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Clearance as illustrated

Blower Clearance(Reference Value) Unit of Measurement: mm

impellers-casing Impeller-ImpellerImpeller-Front

wall Impeller-Rear

Wall Value

Type a(a1,a2,a3) b(b1,b2) c d

SRD-100 0.16~0.45 0.15~0.27 0.20~0.25 0.20~0.25

1. The adjustment of the casing-impeller clearance(a1,a2,a3) is guaranteed by the accuracy of the joint accuracy of the casing and walling. No damage shall be done to the casing and walling.

2. The adjustment of the impeller-impeller clearance (b1,b2): rotate the impellers to the position as indicated in c. Make sure the driven gear is aligned to the driving gear and mark it on the shaft. Then install according to order of the gear retaining ring, retaining gasket, locknut and slightly tighten the nut. Loosen the gear ring to tighten the bolts and adjust the ring so the impeller-impeller clearance is within the scope. Then tighten the bolts.

3. The adjustment of the impeller-side walling axial clearance(c、d): before installing the walling, the axial total clearance C+D (through the adjustment of the casing gasket)need to be ensured. Then through the adjustment of the front bearing gasket to ensure the c and d distribution.

2.4 Installation of the Transmission Parts

!Warning: Use appropriate tools to install the wheel on the shaft and motor.

Hammer is prohibited when installing the wheel or coupling.

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2.4.1 Belt Installation

The belt for the blower is narrow V shaped belt. The correction installation of the wheel and belt will directly affect the life span of the belt and the equipment performance. Following items needs to be taken care of:

1. Before belt installation, loosen the motor tightening bolts and track adjustable screw to shorten the central distance. No prying force shall be used.

2. The belt and grooves shall be free from impurities.

3. In consideration of the preliminary elongation rate, after adjustment, the blower can be operated for 2 hours to ensure the tension. The tension is to ensure no slipping and no tightness. The tension can be measured by the sagging distance when there is a weight. Refer to the following illustration.

The fixed force W vertically works onto the central of the belt, when the sagging satisfies S=0.016a (mm), it indicates the tension is proper. The W is valued in the scope 76.4~101.9N, with median value as the appropriate.

!Warning: If the belt is too tight, the lifespan of the belt and bearing will be

shortened. If too loose, slipping and vibration will be caused.

4. Use ruler or lines to check the position of the wheels. As the following diagram indicates, the axial lines shall be parallel after adjustment. The symmetrical plane of the corresponding grooves shall be overlapped, with deviation of β≤20’，l≤1.6a/1000.

5. After adjustment, the coupling bolts and track adjustable screw must have been tightened.

6. When replacing belt, belts of the same specifications must be used and old and new ones shall not be mixed. Upon wheel replacement, the wheel shall be the same as the previous specifications.

7. Loosen the belts if they are not used for a long time.

!Warning: In order to ensure safety and security, belt hood shall be installed.

2.5 Safety Valve and Check Valve

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2.5.1 Introduction

1. Cautions

1) The safety valve for the blower is metal sealing type with the seat and core assembled together after grinding; therefore, it is not affected by ambient humidity and temperature. If there are foreign objects attached to the seat, when the core works, it will go to the contact surface, causing leakage. In addition, when moving the valves, it shall be handled carefully as collision will cause leakage.

2) The safety valve must be installed on an horizontal pipe through a tee to ensure the axis of it is vertical to the ground.

3) During operation, if the sensitivity of the safety valve is lowered, then it means immediate cleaning to the valve seat and core. The method is to remove the cap and spring and use diesel or petrol to clean it. (The following diagram indicates the structure of the valve.)

A27TW-2Q SVF Type Safety Valve(Thread Type)

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1. Adjusting Bolt 2. Locknut 3. Cap 4. Valve seat

4) All the parts shall be periodically cleaned in order to ensure the life span and its sensitivity.

2. Principle: When the load exceeds the set pressure of the safety valve, the valve opens to prevent blower faults.

!Warning: When the blower is in operation, do not stay around the primary hole of

the safety valve to prevent getting burnt.

2.5.2 Check valve

The check valve has to be installed onto a horizontal pipe. During installation, the valve rotation shaft shall be horizontal and pay attention to the flow direction (refer to the diagram below).

H74W-1C Type Check Valve

□ Reminder: There shall be plenty of space to ensure the opening and closing of the valve.

2.6 Troubleshooting

Troubleshooting Table

Faults Causes Solutions

Insufficient air volume

1. piping leakage

2.Clearance increase

3.inlet clogged

4.belt slipping

1.Check the connections and repair if there are leakages

2. Adjust gap or replace rotor

3.clean filter

4. Adjust the tension or replace belt.

Motor overload

1. Inlet resistance too much

2. Pressure increase enlarged

3. Friction between the cylinder and impellers

4. Speed too high

1.Clean filter

2. Check primary pressure and load

3. Adjust clearance

4. Replace belt wheels

Overheating

1. Pressure increase enlarged

2. Friction between the cylinder and blades

1. Check the inlet and primary pressure and load

2. Adjust clearance

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Faults Causes Solutions

3. Lubricants too much or too less

4. Lubricant oil quality not good

3. Check the oil gauge

4. Replace oil

Noise

1. Mislocation of the synchronized gears and rotors

2.Bearings worn

3.Pressure rise fluctuate widely

4.Gears damaged

5.Safety valve closes and restarts automatically

5. Check valve damaged

1.Correct the position and get them tightened.

2.Replace bearing

3.Check the piping and load

4.Replace gears

5.Check whether there is pressure overload or adjust the safety valve

6.replace check valve

Refuse to start

1.Primary outlet clogged or valve refuses to open

2. Power connection wrong or other electric problems

1. Remove the blockage or open the valve

2. Check the connection or other electrics

Lubricant leakage

1. Oil level too high

2. Seal damaged

1. Lower the oil level

2. Replace seal

Vibration 1. Foundation unfixed

2. Bearing worn

1. Fix the foundation

2. Replace bearing

□ Reminder: Refer to the manual provided by the motor manufacture for the maintenance and service of the motor.

10.3 Main Parts and Consumables

10.3.1 List of Main Parts

10.3.1.1 Main Parts List

Driving Impeller Driven Impeller Sealing Jacket Name Type

No. Qty No. Qty No. Qty

SRD-100 SRD100.1.1 1 SRD100.1.2 1 RD.1-17( )Ⅰ

ARD.1-17( )Ⅱ 2 2

Side Plates Bearing Gear Components

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Name

Type

No. Qty No. Qty No. Qty

SRD-100 RD.1-04 4 NU311/P6

21312 2 2

RD.1-05 RD.1-07 RD.1-08

1 1 1

10.3.2 Consumables

No. Name No. Qty

1 Lock washer 45 GB858-88 2

2 Lock washer 60 GB858-88 2

3 Locknut M45X1.5 RD.1-29 2

4 Round nut M60X2 GB812-88 2

5 Front bearing seat seal gasket RD.1-49 2 sets

6 Rear bearing seat seal gasket RD.1-48 2

7 Casing seal gasket RD.1-40 2

8 Oil box seal gasket RD.1-41 2

9 Structure oil seal B55X78X12 GB9877.1-88 2

10 V belt(with coupling) 5V-1000 3

11

V shaped rubber oil retaining

ring 72X90X5 T08.1 4

12 O ring 55X3.1 GB1235-76 1

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11 Slag Removal System

11.1 Slag Hopper Maintenance and Service

11.1.1 Slag Hopper and Slag Gate Structure

The slag hopper is to temporarily store the furnace slag. The slag from the furnace falls into the hopper and releases great amount of heat and explodes to many small pieces to get stored in the hopper. After a period of time, the slag will be flushed out of the hopper by water through the slag gate and crusher. The water level in the hopper has to be maintained; therefore there are two 6 inch water inlet pipe and drain pipe in the hopper. The structure of the hopper is bottom support. The up water trough is located below the header under the water-cooling wall. The water sealing plate of the header under the water-cooling wall is connected to the water trough to seal the furnace and ensures the water wall expansion and contraction to maintain the stability of the water level. Surrounded the water trough are 10 pieces of 2 inch low pressure water pipe and one overflow pipe to ensure the water level. The 4 corners of the water trough have 4 discharge valves which are used when the furnace is being serviced to drain the water and slag in the water trough. The slag hopper has two halves on the left and right connecting with each other. At the bottom, it is fitted with slag gate and slag crusher.

Slag Gate Structure

The slag gate consists of gate, seat, guiding track, wheel, wheel shaft and cylinder.

11.1.2 Slag Hopper and Maintenance and Service

Item Working Methods and Cautions Quality Standard

1. Preparation

1. Open the drain valve to drain the water.

2. Open the slag gate manhole so it is fully open.

3. Remove the slag on the hopper wall and turn on the slag crusher to discharge the slag through manhole.

Cautions: Do not damage the hopper walls whiling removing the slag. When the slag crusher turns on, there shall be nobody or tools in the hopper.

2. Internal Examination

1. Check on the concrete surface on the internal wall of the hopper. Repair the broken part or crack part. Remove the crack before repair.

2. Slag hopper concrete sleeve replacement

1， Smooth concrete surface without cracks, breakage or arching.

2， The concrete surface after relaying shall

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Item Working Methods and Cautions Quality Standard

shall be after complete removal of the original concrete walling and the strengthening nails.

3. Flush the water nozzle in the slag hopper (including observation lens nozzle) and clear away the slag around the nozzles.

4. Clear and flush the slag in the overflow outlet and overflow water container.

comply with the specifications.

3， The nozzles shall be free from blockage and ejection distance is normal.

4， No Slag in the water drain outlet

3. Water sealing Equipment Examination and Clearance

1.Use high pressure water gun to clear away the slag accumulated in the water trough.

2. Remove the water nozzle in the trough and turn on the flushing valve to examine and flush the trough and nozzle and then re-install.

3. Check the water sealing plate and the bolts connecting the plate and water cooling walls. Replace any warped or broken bolts.

4. Check the surface and welding seam of the tooth shaped dam plate in the water trough and check the slag metal mesh and the welding seam with the fixed parts.

5. Measure the clearance between water seal plate and the bottom of the water trough.

1. No slag, dirt or sand in the trough. No hindrance in the expansion of the water cooling wall.

2. Sealing quality, no leaking and sealing water level constant. No blockage in the flush pipe and nozzle in the trough.

3. No corrosion, deformation of the water sealing plate and the bolts is free from deformation or breakage.

4. No corrosion from the tooth shaped overflow plate. The welding is well done. The slag metal mesh is free from deformation, corrosion.

5. The clearance between the water sealing plate and water trough complies with the design requirements.

Slag Gate Maintenance and Service

Items Procedure and Cautions Quality Standards

1. Dismantling

1. Remove the bolts connecting the slag gate panel and room and remove the panel.

2. Open the slag gate and to its maximum opening and turn off the gas/hydraulic

1. The base antifriction plate shall be worn less than 2mm. When being replaced, the head of the bolts shall be

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controller.

3. Remove the nuts for the guiding wheel and get the wheel out and loosen the bolts for the wheel shaft to get it out.

4. Remove O shaped ring and clean its groove.

5. Close the slag gate and in an off position.

6. Remove the nuts between the piston rod and slag gate and bolts between guiding rod and slag gate. Separate the piston rod and slag gate using gas/hydraulic controller. Then, turn off the controller and cut the power off.

7. Tighten the piston cylinder using steel wire and chain lift and then remove the bolts between the cylinder and piping and cylinder and slag gate. Remove and separate the cylinder and slag gate from the equipment.

Cautions: The exposed part of the piston rod shall be packed and when being lifted, no striking or collision.

8. Remove the slag gate wedge and put a jack under the gate so to get the slag gate out of the guiding track. Tighten the gate and chain lift with metal wire and get the guiding track removed.

9. Move the slag gate out of the base slowly by operating the chain lift.

aligned with the surface.

2. The slag gate is smooth and without deformation. The wear shall be less than 30%.

3. The guiding track is smooth and free from deformation.

4. No corrosion on the rod surface and no deformation. The bolts shall be free from damage. The sealing quality of the cylinder is good.

5. The indicating guiding rod shall be smooth and the indication is correct.

6. After the wheel being reinstalled, it is still smooth.

7. After installation of the gate, it is freely open or close and the clearance between the gate and the track shall be smaller than 0.8mm.

8. The room and the panel joint surface is smooth. When the panel is closed, there shall be no leakage.

2. Installation

1. Clean the slag gate with clean water and check the surface or use clean water to clean the gate base and anti-friction plate. If the friction is too much, replace the plate.

2. Replace those deformed seriously.

3. Clean the gate frame and track with clean water and check the smoothness of the track. Replace if deformed and then install it on the

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frame and tighten with bolts.

4. Lift the gate to the frame and install it based on the guiding track and put back the positioning wedge.

5. Clean the threads of the piston rod with diesel and check the threads. For minor defects such as burr, use file to correct and try with a nut. Replace with a new piston rod if threads are damaged. The seal for the rod shall also be replaced.

6. Lift the cylinder to the gate and get connected. Caution: During the installation, the piston rod shall be backed with the exposed part and threads protected.

7. Reconnect the controlling piping and turn on the gas/hydraulic controller to get the rod and gate connected and fixed with nuts. Then connect the gate with indication rod and adjust the rod to a close position.

8. Open the gas/hydraulic controller so that the gate opens fully and adjust the indication rod correspondingly and adjust the indication section so that it is correct.

9. Clean the guiding shaft and base with diesel and replace O shaped ring and then guide the eccentric part of the shaft to the hole and tighten with bolt and put the sleeve on and tighten with nuts. Note: Grease the wheel and shaft before installation.

10. Turn the gas/hydraulic controller so that the gate is located in an off position and use a jack to jack the gate to the top of the frame.

Caution: Do not overuse force. Measure the clearance between the slag gate and frame. Before adjustment, the bolt shall be loosened and rotate the shaft so that the guiding wheel and the gate wedge is well contacted. Then tighten the bolt and get the jack out. Measure

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again the gap and turn on the controller to move the gate till it can move freely.

11. Use blade to clean the remnant on the joint between the panel and slag room and then close the panel.

11.2 Slag Crusher Maintenance and Service

Item Procedure and Cautions Quality Standard

1. Dismantling

1. Cut the motor power off.

2. Remove the bolts on the coupling hood and remove the hood and the bolts on the couplings.

3. Remove the chain guard bolts and the guard and remove the chain pin to get the chain off and into the diesel.

4. Remove the shaft seal water pipe and water outlet of the slag crusher.

5. Remove the connecting flange bolts between the casing and the bottom of the slag hopper.

6. Heat the gears and chain wheels and remove the gears and chain wheels with a puller.

Caution: before dismantling chain wheels, first use steel wire to connect them to the moving crane and tighten the wire a bit. When heating, it shall be done evenly.

7. Remove the bearing seat at both sides of the roller and use flame to heat the bearings’ internal rings respectively and separate the bearing with the roller.

Caution: Heating the rings evenly.

8. Remove the shaft seal filler cover bolts and remove the cove and the filler.

9. Remove the bolts on the side plates of the casing and remove the anti-friction ring and separate the casing and side plates.

10. Lift the roller onto a wood and heat the sleeve

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and separate the sleeve from the roller with a puller.

2. Service parts

1. Clean the chain wheel and gears in diesel and check the gearing face. Use sand paper to grind the shaft hole and chain grooves.

Caution: Grease the sand paper first before application.

2. Use diesel to clean the bearing seat and bearings. Check the joint of the seat and bearing. Check the internal and external rings and rollers of the bearings. Measure the bearing clearance. If too large, replace bearings.

3. Clean the shaft sleeve and bearing jacket in diesel and check the inside and outside. Use sand paper to grind the sleeves and jacket.

Caution: Grease the sand paper first before application.

4. Clean the casing and anti-friction ring with clean water. Replace the ring if it is damaged.

5. Clean the roller teeth with clean water and check the gearing face.

6. Clean the roller with diesel and check the shaft surface. Replace if damage is there.

1. The chain wheel and gear gearing face shall be smooth, free from corrosion, breakage, deformation. The shaft chain groove shall be free from burr and deformation.

2. No corrosion in the bearing seat and no cracks. The bearing roller shall be no friction and the bearing clearance shall be 0.08-0.1lmm.

3. The wear of the anti-friction ring shall be less than 50%.

4. The wear of the roller teeth shall be less than 7 mm.

5. The roller shaft shall be smooth and free from corrosion and the chain groove shall be free from burr and deformation.

6. There shall be no corrosion or friction in the sleeves.

3. Installation

1. Put the filler cover and water retaining ring onto the roller shaft. The bearing to be heated in oil and put on the shaft.

2. Use blade to clean the remnant on the joint

1. The joint face between the casing and slag hopper is smooth with good sealing quality. No

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face between casing and slag hopper and on the side plates and then wipe clean with blade cloth.

3. Flush the casing inside with clean water and install the anti-friction plate.

4. Install the side plate on one side of the casing.

Caution: Sealant shall be applied to the joint surface and bolts.

5. Fix the bottom of the bearing seat and support.

6. Lift the roller and components to the casing and install the other side plate.

7. Rotate the shaft so that the axial teeth of one roller is located in the middle of that of another.

8. Heat the driving gear of the roller into the oil to get heated and then put into the shaft and get to the gearing location. The gear installation shall be according to diagram 7-4.

Caution: When reinstalling the gears, the relative position of the two shafts shall be temporarily fixed.

9. Use a tommy bar to move the roller so that it is in the middle of the casing.

10. Loosen the bolts between the bearing seat and support, and add a gasket to the bearing seat and support till the two shafts can rotate freely. Then use filler gauge to measure the clearance between the sleeve and casing shaft bore. If the clearance is bigger than 0.05mm, then readjust the gasket till it is smaller and ensure the shafts can rotate freely.

11.Install the bearing seat position pin and tighten the bottom position bolts of the bearing seat and grease the bearing seat and install the bearing seat cover.

Caution: Use blade cloth to clean the bearings and the bearing seat before the cover is put on.

impurities in the casing.

2. Good sealing quality of the casing.

3. Installation tension for the gear and chain wheel is 0-O. 03mm.

4. Even clearance between the roller shaft and the side plates. The roller shaft could rotate flexibly.

5. The shaft has good shaft seal quality.

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12. Install the shaft seal filler, cover and water retaining ring.

Caution: During the installation of the filler, the filler direction shall be 90 degrees from each other.

13. Use sand paper to grind the shaft gland groove and key at the chain wheel side and then heat the chain wheel shaft bore. Strike the chain wheel with copper bar as cushion so that the wheel goes to shaft and to the shaft shoulder. Install the chain wheel position pin.

14. Move the slag crusher to under the slag hopper and like the slag hopper and the crusher with bolts, tightened.

Caution: The joint flange bolts between the crusher and the slag hopper shall be applied sealant.

4. Disintegrate the reducer

1. Remove the bolts between the reducer and coupling and bolts at the bottom of the reducer

2. Heat with a flame the wheel of the small chain wheel and remove it from the reducer with a puller.

Caution: Before removal, mark the position on the shaft.

3. Turn on the oil drain of the reducer to get the lubricant out and check the quality. If too bad, replace the lubricant.

4. Open the side cover of the reducer and remove the oil seal. Use copper tools to strike the gear and bearing internal ring to get it separated from the shaft.

5. Use diesel to clean the reducer box and transmission gear and bearing and check the shaft surface, gearing face and bearing.

6. Use diesel to clean the small chain wheel and

1. Lubricant no quality change, no emulsification.

2. Gearing face no deformation, cracks, wear, and corrosion.

3. Transmission shaft surface smooth with no wear.

4. Side cover of the reducer no cracks and box no cracks.

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the shaft bore.

5. Reducer Installation

1. Use blade cloth to clean the reducer and clean the joint surface of the casing.

2. Put the bearing and gear into the oil to get heated and put onto the shaft.

3. When the transmission shaft components are put into the reducer, fix them and rotate them to check the flexibility.

4，Install the side covers.

Caution: the joint surface shall be greased.

5. Fill in lubricant till the specified level.

6. Install the chain wheel to the marked position and tighten it using bolts.

1. Inside the reducer is clean and dry.

2. The tension of the internal ring of the bearing is 0.01—0.03mm and for the gear is 0.03—0.05mm.

6. Assembling

1. Firmly fix the reducer to the foundation platform and restore the chain. Adjust the bottom position bolts to adjust the parralellity and sagging amount.

2 ， Connect the reducer together with the coupling and find the coupling center.

3，Install the coupler and the chain guard.

4. Install the shaft seal water pipe and slag crusher outlet.

1. The chain parallelism deviation shall be less than 2 mm. The free sagging shall be smaller than 40mm.

2. The coupling center deviation smaller than 0.10mm.

3. No deformation and leakage of the chain guard.

4. The shaft seal water pipe has no leakage.

11.3 Slurry Pump Maintenance and Service

11.3.1 Technical Specifications

High pressure pumps are horizontal, single impeller, suction and centrifugal pump with double casing. The casing has replaceable internal sleeves including impeller, sleeve, plates, pump and cover. The pump is made of ductile cast iron. The front and the back of the impellers have back blades to reduce leakage and to improve the life span and efficiency. The inlet of the pump is horizontal and sealed with fillers and it is

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equipped with specialized shaft seal pump to provide enough water.

The bearing is single layer heavy duty cone bearing, capable of bearing maximum axial and horizontal load. The bearing is oil lubricated and on both sides of the bearing box, it all has sealing covers, labyrinth sleeves and rings to prevent any invasion of foreign materials.

11.3.2 Slurry Pump Maintenance

Items Procedures and Cautions Quality Standard

1. Service Preparation

1. Turn off the power for the slurry pump.

2. Close the inlet and outlet valves for the slurry pump. Close the shaft seal water inlet valve.

Caution: As the inlet and outlet valves are closed, inside the pump and the inlet and outlet piping there is still water and pressure; therefore, the piping connections shall be loosened to drain the remaining water and pressure and then, dismantle the outlet pipe.

3. Remove the bolts for the coupling hood and the hood and the bolts for the couplings.

2. Dismantling 1. Remove the connecting pin between the pump and the motor.

2. Remove the inlet and outlet piping connectors, and then remove the flange bolts to get the piping out.

3. Remove the pump cover bolts with a spanner and lift the cover to a designated place. Caution: The cover shall be placed on top of a wood or rubber.

4. Remove the 2 position iron plates for the pump jacket and lift the jacket out.

5. Insert a steel pipe or bar into the impeller chamber with another end on the ground. Use special tube on the shaft gland and turn anti-clockwise to get the impeller out of the shaft.

Caution: Use steel wire to connect the

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impeller with the traveling crane, tightened.

a. Remove the filler cover bolts and the cover and pull out all the fillers.

6. Strike the sleeve with hammer and copper bar so that it gradually comes out. Remove the 4 hold-down bolts between the bearing components and the support, and the adjustment bolts in the axial direction. Then remove the bearing components and water sealing ring.

7. Remove the locknut for the bearing components with a hook wrench and the pins at the front and back of the cover. Use an iron bar to pry open the cover and pull the labyrinth sleeve and cover out.

8. Use copper bar as a cushion to strike the pump shaft so that it retreats till the bearing comes out from the bearing box and then remove the pump shaft from the bearing box.

9. Use heating methods evenly heat the bearing and lubricant retainer ring on the pump shaft to get them out of the shaft.

10. Get the positioning wedge for the front plate of the pump cover out and place the cover inlet side upwards on the ground. Use copper bar as a cushion to separate the front cover with the pump cover. Then remove the nuts of the rear plate and strike the bolt ends till the rear plate separate.

11. Mark the position of the filler box on the pump and use copper bar as a cushion to strike the filler box cover till it gets separated with the pump.

3. Parts Maintenance and Service

1. Check the degree of wear on the pressure enlarge outlet pipe of the slurry pipe. If serious, replace.

2. Check the wedge shaped connecting

1. The pressure enlargement outlet pipe wear shall be smaller than 2mm. The wedge seal ring shall be free

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rubber seal ring. If worn, replace.

3. Clean the front and back plates of the pump cover and the cover with diesel and check the level of wear of the back plate. If serious, replace the back plate. If there is crack on the pump cover, replace.

4. Clean the impeller jacket and check the degree of wear. If the wear is serious at the internal wall ant the outlet, replace it.

5. Clean the impeller and check the blades and its working surface and if they are worn, replace them.

6. Use diesel to clean the shaft sleeve and water seal ring and check their surfaces.

7. Use diesel to clean the bearing and labyrinth seal ring and check the bearing’s rollers, internal and external rings and labyrinth ring.

8. Clean the sealing filler box with diesel and check the circumvent surface.

9. Clean the rear pump casing and check the surface whether there are cracks. If there are, replace.

10. Check the center straightness of the support trough and check the trough surface and support.

11. Clean the pump shaft with diesel and check the bearings, oil retaining parts and key way. Use fine greased sand paper to grind the shaft and key way surface. Check the threads of the shaft gland.

12. Periodically check oil level and quality of the liquid coupler.

from worn and deformation.

2. The wear to the front and back plates shall be less than 5mm. There shall be no cracks on the pump cover. The sealing gasket shall not be worn.

3. No serious wear on the internal wall and the outlet of the jacket.

4. The wear to the impeller front diameter and the front and rear back blades shall not be more than 3mm. The blades shall be free from corrosion and cracks. The threads of the impeller shall be damage free.

5. The sleeve surface shall be smooth. Replace if the wear is more than 1mm. The clearance between the bore of the sleeve and shaft shall be 0.04mm-0.06mm. The water seal ring shall be complete. The surface shall be not rusted or scaled.

6.The internal and external ring of the bearing and rollers shall be wear free, corrosion free and no color change. The tension is similar. The clearance between the internal ring and shaft shall be -+0.01mm. The clearance between the external ring and bearing seat bore is 0.06mm-0.10mm, and the same to the bearing box

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bore. No damage to the labyrinth ring.

7. The filler box shall be free from cracks with smooth surface.

8. The bottom pump casing shall be free from cracks.

9.The support trough center straightness deviation shall be less than 0.02 mm and the trough surface shall be smooth and wear free. The support shall be wear free and crack free.

10. The pump shaft surface shall be smooth and free from friction. The shaft gland threads shall be free from damage.

4. Assembling 1. Put the filler box into the pump to the marked position and use copper bar as a cushion to strike till the position is correct.

2. Put the back plate seal ring into the groove and when it is smooth, then put the back plate on to the pump with bolts.

Caution: Bolts shall be tightened with equal strength.

3. Use blade cloth to clean the shaft surface and then grease the surface.

4. Check and clean the joint surface and use steel wire to lift the pump to connection place to get connected with bolts.

Caution: Replace the sealing gasket for the joint surface and the surface and the bolts shall be sprayed with sealants.

5. Connect the pressure enlarging pipe with

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outlet pipe using connector.

Caution: Replace the rubber gasket.

6. Connect the inlet and water pipe with flange and tightened with bolts equally.

Caution: The sealing gasket of the joint shall be replaced.

11.4 Dehydration Granary Maintenance and Service

11.4.1 Brief introduction

The dehydration granary is a continuous dehydration equipment for the wet slag. A set of the dehydration equipment consists of two granaries. When one of them is filled with slag, dehydration process will initiate. The wet slag mixture will be switched to another granary. After dehydration, the water content in the slag will be greatly reduced and the slag will be dry and falling apart. Then through the slag gate to fill in a tipper to be transported. The two granaries alternate to dehydrate.

The dehydration granary is shaped cylinder like on the top and cone like at the bottom. The top has income slag gate and at the bottom, there is outgoing slag gate. The accessories include: vibrators, water removal elements, diffusion grids, water flushing piping, and valves.

11.4.2 Procedure and Quality Standards

Item Maintenance Quality Standard

1. Preparation

1. Check the equipment maintenance and service logbook.

2. Prepare all the spare parts and tools.

3. Process a maintenance and service pass.

1. The slag incoming gate and water flushing valve can be closed firmly without leakage.

2. Turn off the power for the vibrators and slag outgoing gate.

2. Dehydration granary and accessories Maintenance

1. Check whether there are cracks or leakage from the dehydration granary.

2. Check whether the columns and support for the granary are firm.

3. Check the downflow weir is leveled.

4. Check the diffusion grid and

1. The granary is firm and free from cracks and leakage.

2. The columns and support are reliable.

3. If the distribution grooves are worn, it shall be repaired by welding.

4. The downflow level (tooth bottom level) difference shall be within ±2mm.

5. The water removal elements shall be

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distribution grooves are worn.

5. Check whether the water removal elements are scaled or clogged.

free from scales or clogging.

3. outgoing slag gate maintenance

1. The maintenance for the cylinder shall be carried out according to the appendix.

2. Examine and replace the inflatable seal ring.

1) Remove the side plates at the slag outgoing gate.

2) Open the slag outgoing gate and remove the inflatable seal ring positioning.

3) Remove the damaged inflatable seal ring.

4) Clean the gate seat and inflate the new inflatable ring together with soap water sprayed and install it.

5) Install the positioning and bolts.

6) Install the slag outgoing gate plates and close the gate.

3. Check the wearing level of the gate.

4. Check the rollers, roller bearings and lubrication.

5. The clearance examination and adjustment for the gate and gate seat

1) Use filler gauge to check the clearance between the gate and the gate seat. If the clearance is not equal, then adjust..

2) The method: Adjust the positioning bars at the gate corners

1. Cylinder sealing Ok without leakage.

2. The inflatable work pressure between 0.3~0.5MPa.

3. Replace damaged rings and worn rings.

4. The rollers are complete and contacts well with the track.

5. The roller bearing is Ok with enough lubrication.

6. The clearance between the gate and the seat is equal with a distance between 1.5 to 4mm.

7. The slag outgoing gate works well.

8. If the wall to the slag outgoing granary is damaged, repair or replace it.

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to move it upwards or downwards and measure the clearance with filler gauge.

4. Flushing water valve overhaul

1. Check the valve property to ensure it can be closed firmly.

2. Check the lead screw, valve seat, valve and hand wheel to see whether there is crack or damage

3. Check the support to the piping. Weld any broken pipes.

4. Replace valve packing gland

1. The valve is free from leakage and works well.

2. The piping is free from clogging and with firm support.

3. Replace or repair damaged valves.

5. Trial Run

1. Try water experiment to the dehydration granary to check the gate property and sealing property.

2. Clear the work site.

1. The gates work well.

2. The inflatable sealing ring works well.

3. Ensure the site is clean with equipments clearly labeled.

11.5 Maintenance of Concentration Tank and Buffer Tank

11.5.1 Maintenance Period: As per the system overhaul.

11.5.2 Maintenance Items

1. Check the slag removal of the concentration tank.

2. Check the slag removal of the buffer tank.

11.5.3 Maintenance procedure and quality standards.

Concentration tank clearance

1. Stop the slurry pump, and slag flushing pump. Close the slag incoming gate, water removal gate and flushing gate of the dehydration granary.

2. First, use dredge to pump the slag water of the concentration tank to the ash slurry pond, and then with mortar pump, pump to the disposal site.

3. When the slag water is lowered to a certain level, high pressure water flushing shall be carried out to remove the slag at the bottom.

4. When it reaches the bottom, and the dredge pump refuses to work then a diving pump shall be used.

5. Manually clears any clogs at the bottom until the bottom is clean.

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Buffer Tank Clearance

Ditto above.

11.6 Maintenance of Pumps in the Slurry System

11.6.1 High, Medium, and Low pressure pumps

High, medium, and low pressure pumps are horizontal, single impeller, suction and centrifugal pump with double casing. The casing has replaceable internal sleeves including impeller, sleeve, plates, pump and cover. The pump is made of ductile cast iron. The front and the back of the impellers has back blades to reduce leakage and to improve the life span and efficiency. The inlet of the pump is horizontal and sealed with fillers and it is equipped with specialized shaft seal pump to provide enough water. The maintenance to the three pumps is similar. The following takes slurry pump for example.

11.6.1.1 High Pressure Pump Maintenance


1. Service Preparation

1. Turn off the power for the slurry pump.

2. Close the inlet and outlet valves for the slurry pump. Close the shaft seal water inlet valve.

Caution: As the inlet and outlet valves are closed, inside the pump and the inlet and outlet piping there is still water and pressure; therefore, the piping connections shall be loosened to drain the remaining water and pressure and then, dismantle the outlet pipe.

3. Remove the bolts for the coupling hood and the hood and the bolts for the couplings.

2. Dismantling 1. Remove the connecting pin between the pump and the motor.

2. Remove the inlet and outlet piping connectors, and then remove the flange bolts to get the piping out.

3. Remove the pump cover bolts with a spanner and lift the cover to a designated place. Caution: The cover shall be placed on top of a wood or rubber.

4. Remove the 2 position iron plates for the pump jacket and lift the jacket out.

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5. Insert a steel pipe or bar into the impeller chamber with another end on the ground. Use special tube on the shaft gland and turn anti-clockwise to get the impeller out of the shaft.

Caution: Use steel wire to connect the impeller with the traveling crane, tightened.

a. Remove the filler cover bolts and the cover and pull out all the fillers.

6. Strike the sleeve with hammer and copper bar so that it gradually comes out. Remove the 4 hold-down bolts between the bearing components and the support, and the adjustment bolts in the axial direction. Then remove the bearing components and water sealing ring.

7. Remove the locknut for the bearing components with a hook wrench and the pins at the front and back of the cover. Use an iron bar to pry open the cover and pull the labyrinth sleeve and cover out.

8. Use copper bar as a cushion to strike the pump shaft so that it retreats till the bearing comes out from the bearing box and then remove the pump shaft from the bearing box.

9. Use heating methods evenly heat the bearing and lubricant retainer ring on the pump shaft to get them out of the shaft.

10. Get the positioning wedge for the front plate of the pump cover out and place the cover inlet side upwards on the ground. Use copper bar as a cushion to separate the front cover with the pump cover. Then remove the nuts of the rear plate and strike the bolt ends till the rear plate separate.

11. Mark the position of the filler box on the pump and use copper bar as a cushion to strike the filler box cover till it gets separated with the pump.

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3. Parts Maintenance and Service

1. Check the degree of wear on the pressure enlarge outlet pipe of the slurry pipe. If serious, replace.

2. Check the wedge shaped connecting rubber seal ring. If worn, replace.

3. Clean the front and back plates of the pump cover and the cover with diesel and check the level of wear of the back plate. If serious, replace the back plate. If there is crack on the pump cover, replace.

4. Clean the impeller jacket and check the degree of wear. If the wear is serious at the internal wall ant the outlet, replace it.

5. Clean the impeller and check the blades and its working surface and if they are worn, replace them.

6. Use diesel to clean the shaft sleeve and water seal ring and check their surfaces.

7. Use diesel to clean the bearing and labyrinth seal ring and check the bearing’s rollers, internal and external rings and labyrinth ring.

8. Clean the sealing filler box with diesel and check the circumvent surface.

9. Clean the rear pump casing and check the surface whether there are cracks. If there are, replace.

10. Check the center straightness of the support trough and check the trough surface and support.

11. Clean the pump shaft with diesel and check the bearings, oil retaining parts and key way. Use fine greased sand paper to grind the shaft and key way surface. Check the threads of the shaft gland.

12. Periodically check oil level and quality of the liquid coupler.

1. The pressure enlargement outlet pipe wear shall be smaller than 2mm. The wedge seal ring shall be free from worn and deformation.

2. The wear to the front and back plates shall be less than 5mm. There shall be no cracks on the pump cover. The sealing gasket shall not be worn.

3. No serious wear on the internal wall and the outlet of the jacket.

4. The wear to the impeller front diameter and the front and rear back blades shall not be more than 3mm. The blades shall be free from corrosion and cracks. The threads of the impeller shall be damage free.

5. The sleeve surface shall be smooth. Replace if the wear is more than 1mm. The clearance between the bore of the sleeve and shaft shall be 0.04mm-0.06mm. The water seal ring shall be complete. The surface shall be not rusted or scaled.

6.The internal and external ring of the bearing and rollers shall be wear free, corrosion free and no color change. The tension is similar. The clearance between the internal ring and shaft shall be -+0.01mm. The clearance between the external ring and bearing seat bore is

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0.06mm-0.10mm, and the same to the bearing box bore. No damage to the labyrinth ring.

7. The filler box shall be free from cracks with smooth surface.

8. The bottom pump casing shall be free from cracks.

9.The support trough center straightness deviation shall be less than 0.02 mm and the trough surface shall be smooth and wear free. The support shall be wear free and crack free.

10. The pump shaft surface shall be smooth and free from friction. The shaft gland threads shall be free from damage.

4. Assembling 1. Put the filler box into the pump to the marked position and use copper bar as a cushion to strike till the position is correct.

2. Put the back plate seal ring into the groove and when it is smooth, then put the back plate on to the pump with bolts.

Caution: Bolts shall be tightened with equal strength.

3. Use blade cloth to clean the shaft surface and then grease the surface.

4. Check and clean the joint surface and use steel wire to lift the pump to connection place to get connected with bolts.

Caution: Replace the sealing gasket for the joint surface and the surface and the bolts shall be sprayed with sealants.

5. Connect the pressure enlarging pipe with

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outlet pipe using connector.

Caution: Replace the rubber gasket.

6. Connect the inlet and water pipe with flange and tightened with bolts equally.

Caution: The sealing gasket of the joint shall be replaced.

11.6.2 Backwashing Pump

Refer to the maintenance period, items and quality standards of the slurry pump.

11.6.3 Dredge Pump


11.6.4 Lift Pump


Boiler & Auxiliaries Maintenance Manuall Qn1 Sec g 04 Tp 009

Documents

ball passing

ball passing

obvious color

heat transfer

heat transfer

pulverized

thermal machinery

light transmission