DESIGN GUIDE-FICHTNER.pdf

FICHTNER India

DESIGN GUIDES CONTENTS

APPROVED BY : DEPARTMENT : MECHANICAL DATE : 02/06/99 PAGE : 1 of 2

C:\Siva\REFERENCES\USEFUL BOOKS\DESIGN GUIDE-FICHTNER\DESIGN GUIDE CONTENT.doc

Sl. No.

W.I. No. Rev. Description Date of Issue

1. WI-ME-DSN-100-001 R-1 LHV, HHV Calculations Fuel Oil 11/04/98

2. WI-ME-DSN-100-002 R-1 Flue Gas Dew Point Calculations 11/04/98

3. WI-ME-DSN-100-003 R-1 Fan Power Calculations 11/04/98

4. WI-ME-DSN-100-004 R-1 Oil Heater Steam Requirement Calculations

11/04/98

5. WI-ME-DSN-100-005 R-1 LHV, HHV Calculations Coal 11/04/98

6. WI-ME-DSN-100-006 R-1 LHV, HHV Calculations Gaseous fuel (Natural Gas)

11/04/98

7. WI-ME-DSN-100-007 R-1 Stoichometric Air Reqt. Solid and Liquid Fuels

11/04/98

8. WI-ME-DSN-100-008 R-1 Recommended feed water & boiler water quality for power plant application

11/04/98

9. WI-ME-DSN-100-009 R-1 Boiler Blow Down Calculations 11/04/98

10. WI-ME-DSN-100-010 R-1 Chimney Sizing 11/04/98

11. WI-ME-DSN-100-011 R-1 Emission / Ambient air quality calculations

11/04/98

12. WI-ME-DSN-103-001 R-1 Ash handling system Typical write up 11/04/98

13. WI-ME-DSN-108-001 R-1 Raw Water Analysis Conversion factors for Ionic loads

11/04/98

14. WI-ME-DSN-108-002 R-1 Raw Water Analysis Format 11/04/98

15. WI-ME-DSN-122-001 R-1 Cooling Tower Blow Down Evaporation & Drift Loss Calculations

11/04/98

16. WI-ME-DSN-123-001 R-1 Horizontal pump Vs Typical write up vertical pump

11/04/98

17. WI-ME-DSN-124-001 R-1 Merits / Demerits of Plate Type Heat Exchanger

11/04/98

18. WI-ME-DSN-126-001 R-1 Water Cooled Condenser Sizing 11/04/98

19. WI-ME-DSN-126-002 R-1 Air Cooled Heat Exchanger / condenser

11/04/98

20 WI-ME-DSN-166-001 R-0 Guidelines on Basic Aspects for Fire Protection System

02/06/99

21. WI-ME-DSN-180-001 R-0 Standard tank size and weight chart 13/04/98

22. WI-ME-DSN-180-002 R-0 Tank cost estimates 13/04/98

23. WI-ME-DSN-180-003 R-0 Heating coil size calculation for storage tanks

13/04/98

24. WI-ME-DSN-180-004 R-0 Heat loss calculation for vertical cylindrical storage tank

13/04/98

25. WI-ME-DSN-196-001 R-1 Insulation Thickness Calculations 11/04/98

26. WI-ME-DSN-196-002 R-1 Steam Trap Selection 11/04/98

27. WI-ME-DSN-196-003 R-1 Pressure Temperature Rating 11/04/98

28. WI-ME-DSN-196-004 R-0 Standard flange dimension data 13/04/98

29. WI-ME-DSN-196-005 R-1 Weld Joint Quantity Calculation 11/04/98

FICHTNER India

DESIGN GUIDES CONTENTS

APPROVED BY : DEPARTMENT : MECHANICAL DATE : 02/06/99 PAGE : 2 of 2

C:\Siva\REFERENCES\USEFUL BOOKS\DESIGN GUIDE-FICHTNER\DESIGN GUIDE CONTENT.doc

Sl. No.

W.I. No. Rev. Description Date of Issue

30. WI-ME-DSN-196-006 R-1 LPT Quantity Calculations 11/04/98

31. WI-ME-DSN-196-007 R-1 Allowable Pipe Span 11/04/98

32. WI-ME-DSN-196-008 R-1 Scope of IBR Documentation-A Guide Line

11/04/98

33. WI-ME-DSN-196-009 R-1 Mild Steel Pipe - Size Dimension & Weight

11/04/98

34. WI-ME-DSN-196-010 R-1 Seamless or Electrically Welded Steel Tubes / Pipes IS 3589

11/04/98

35. WI-ME-DSN-196-011 R-1 Pipe Thickness Calculation (IBR Ready Reckoner)

11/04/98

36. WI-ME-DSN-196-012 R-0 Pipe sizing calculation Steam service 13/04/98

37. WI-ME-DSN-196-013 R-0 Pipe sizing calculation Water service 13/04/98

38. WI-ME-DSN-196-014 R-0 Piping sizing calculation Air service 13/04/98

39. WI-ME-DSN-196-015 R-0 Allowable velocities in pipes 13/04/98

40. WI-ME-DSN-700-015 R-0 List of Calculation in EXCEL available in Mechanical department

02/06/99

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DOC. NO. WI-ME-DSN-100-001 REV. NO. R-A PAGE 1 OF 1

C:\Siva\REFERENCES\USEFUL BOOKS\DESIGN GUIDE-FICHTNER\WI-ME-DSN-100-001.doc

FORM T10 REV - A

LHV, HHV CALCULATIONS - FUEL OIL

Qv = 12,400 - 2100 d2 % H = 26 - 15d Qp = Qv - 50.45 X %H Where, Qv = Higher heating value at constant volume in kcal/kg of oil, free of

water, ash and sulphur, final products being Co2 gas + water. Qp = Net Heat of combustion (LHV) at constant pressure (atm) in kcal/kg -

free of water, ash and sulphur, final products being Co2 gas + H2O (vapour)

%H = Percentage of Hydrogen in the Hydrocarbon fuel. d = Specific gravity of the fuel at 60F. CORRECTION VALUES FOR WATER, ASH AND SULPHUR CONTENT IN FUEL Qv = Qv - 0.01 Qv (%H2O + % ASH +%S) + X(%S) Qp = Qp - 0.01 Qp (%H2O + % ASH + %S) + X(%S) - Y (%H2O) Where Qv = Higher Heating Value at constant volume per unit quantity of fuel oil

containing water, ash, sulphur. Final products being ash, gaseous Co2, So2 and liquid water.

Qp = Net heat of combustion (LHV) at constant pressure per unit quantity

of fuel oil containing water, ash and sulphur. Final products being ash, gaseous Co2, So2 and H2O.

% Ash = percentage of ash determined by ASTM D-482. % H2O = percentage of water determined by ASTM D-95. % S = percentage of sulphur determined by ASTM D-129. X & Y are constants which vary in value depending upon the units in which heating

value is reported.

UNIT X Y kcal/kg 22.5 5.85

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C:\Siva\REFERENCES\USEFUL BOOKS\DESIGN GUIDE-FICHTNER\WI-ME-DSN-100-002.doc FORM T10 REV - A

FLUE GAS DEW POINT CALCULATIONS

Flue gas Dew point temperature is determined from the following correlation : 1000 ------- = 1.7842 + 0.0269 * log(Pw) - 0.1031 * log(PS03) + Tdp 0.0329 * log (Pw) * log (PSo3) Tdp = Flue gas dew point temperature in k. Pw = Partial pressure of water vapour. PS03 = Partial pressure of sulphur tri-oxide. DEW POINT : Dew point is the temperature at which an un-saturated gas vapour mixture becomes

saturated as a result of iso-baric cooling at constant absolute humidity. The dew point is also the saturation temperature corresponding to the initial partial pressure of the vapour. If the cooling proceeds further, both temperature and the absolute humidity decrease and rapid condensation of water vapour takes place.

EFFECT OF SULPHUR IN FUEL ON DEW POINT OF COMBUSTION GASES Sulphur forms sulphur-di-oxide and a small but significant amount of sulphur-tri-oxide,

when burnt. The sulphur tri-oxide that is formed can combine with water vapour to form sulphuric acid. The sulphuric acid will remain in the vapour state as long as the temperature of the exhaust gas is above dew point of the gas. When in the vapour state i.e above dew point it causes no corrosion.

If however, the temperature of stack gases is lowered below the dew point, sulphuric

acid will condense out and cause corrosion of metal.

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FORM T10 REV - A

FAN POWER CALCULATIONS

The Input Required for fan power calculations are : (i) Density of the fluid (kg/m3), (ii) Flow rate of the fluid (m3/sec), Q (iii) Head to be developed (mWC), H

(iv) Fan efficiency () (v) Accelaration due to gravity (m/sec2), g Power of the fan drive motor Nmot, KW : m Q H g ------------ 1000 tr where m = 1.05 to 1.2 is the power reserve factor If the fan is directly connected to the motor, the transmission efficiency tr = 1 for V - belt transmission tr = 0.92 The fan power consumption depends on the gas quantity and the resistance through

the boiler gas passes which will be dependant on the particular boiler design and the

range of fuels to be burned.

FAN SELECTION CRITERIA a) Capacity and Head In selecting a fan, one is guided by the maximum capacity Q and head H required of

the fan as applied to a given air or gas duct work. A margin in pressure and volume

over normal requirements is necessary to compensate for boiler fouling, adverse

combustion conditions, poor fuel and to provide cover for possible slight errors in the

estimates of draught system requirements. The margin is usually about 20% for

volume and about 50% for system resistance. The cost of

providing margins in fan duty, is higher than for most other items of plant owing to the

square law relating volume to pressure and to the cube law relating volume to

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FORM T10 REV - A

horsepower. If a 20% margin of volume capacity is required, the pressure needed

would be about 1.5 times and the horsepower about 1.75 times the requirements for

the net capacity. The penalty paid for excessive fan capacity is therefore, severe both

in capital and operating costs.

b) Fan Speed The following is an illustration of the magnitude of i-d fan power consumption

for one 500 MW boiler provided with two-speed i.d fans. To handle the boiler C.M.R gas flow at the lower speed of 490 rev/min each fan would require 1320 b.h.p. Changing to high speed at this point closes the inlet vane gear and results in a reduction in fan efficiency which would require an additional 200 b.h.p per fan. With both i.d fans running at top speed at boiler C.M.R, an additional 400 b.h.p is required and it can, therefore, be appreciated that low speed operation should be used on all possible occasions. In this instance, the rated i.e fan motor horse power to cater for the fan design margins was 2290 b.h.p at 590 rev/min.

c) Density of the Fluid The capacity of the forced draft fans is to be determined at the lowest density

condition prevailing at the site. For the same heat input to boilers, the air quantity required in mass flow units

(kg/hr) remains the same irrespective of the ambient conditions. W = 60 q where w = mass flow, kg/hr = density, kg/m3 q = Volumetric flow, m3/hr Fans discharge constant volumetric flow at any density. Hence if the fan is

sized to give a particular volumetric flow at the high density condition, the mass flow would decrease when density decreases as can be seen in the equation above. Hence the fan must be sized to deliver the volumetric flow at the lowest density condition, in which case the output will be higher at the higher density condition, which can be then controlled.

Also, the gas pressure drop p in mmwc across the wind box is proportional

to w2/l. If the air density decreases as at high-temperature conditions, the pressure drop increases, because W remains unchanged for a given heat input. Considering the fact that H/ is a constant for a given fan, where H is the static head in mmwc, using the lowest ensures that the head available at higher density will be larger.

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FORM T10 REV - A

OIL HEATER STEAM REQUIREMENT CALCULATIONS

a) Continuous steam requirement for Fuel Oil Tank Floor Heaters 1. Minimum temperature = tmin C 2. Temperature of oil which is to be maintained in the fuel oil tank = t C 3. Heat transfer coefficient between the tank surface and atmosphere = h kcal/hr/m2 C 4. Fuel oil tank dimensions Diameter = `D m. Height = `H m. 5. Surface area of the tank = DH m2 6. Heat loss from the tank surface to the atmosphere taking 10% margin (Hl) = h x A (t - tmin) x 1.1 7. Auxiliary steam parameters available are: Pressure = `p ata Temperature = T C Enthalpy = Hs kcal/kg 8. Enthalpy of condensate at outlet = Hc kcal/kg 9. Steam required for floor heater

for heating the tank = H

Hs Hckg hrl

( )/

b. Steam requirement for storage tank out flow Heater 1. Number of heaters working at a time (Assumed one tank working at a time) = one (1) 2. Fuel oil flow through heater = mfo

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FORM T10 REV - A

3. Average temperature of fuel oil at the inlet to outflow heater = t1 C 4. Temperature of the fuel at the outlet of outflow heater = t2 C 5. Steam parameters available are Pressure = p kg/cm2 Temperature = T C Enthalpy = Hs kcal/kg. 6. Condensate enthalpy at the outlet of the heater = Hc kcal/kg. 7. Specific heat of the fuel oil = Cp kcal/kg C 8. Heat energy required for raising the temperature of the oil = mfo * Cp * (t2 - t1) 9. Steam required for the outflow

heater taking 10% margin = mfo Cp t t

Hs Hcx* * ( )

( ).2 1 11

C. Steam requirement for the steam coil air preheater 1. Heat input to SG at BMCR = Q kcal/hr. 2. Coal required to give this

heat energy (mc) = Q

C V of coalkg hr

. ./

3. Coal required at 30% MCR (mc30) = mc * 0.3 kg/hr 4. The theoretical air required for burning the coal (kg/kg of coal = ma 5. Actual air required (with 20% excess air) (mact) = 1.2 * ma (kg/kg of coal) 6. Air required at 30% MCR (Ma) = mact x mc30 kg/hr

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FORM T10 REV - A

7. Aux. Steam parameters Pressure = pata Temperature = T C Enthalpy = Hs kcal/kg 8. Enthalpy of condensate at the outlet of SCAPH = Hc kcal/kg 9. Minimum ambient air temperature (for the design of SCAPH) = t1 C 10. Temperature to which the air is to be raised = t2 C 11. Specific heat of air = Cpa kcal/kg C 12. Heat energy required to raise air temperature to t2C = Ma * Cpa * (t2 - t1) kcal/hr. 13. Steam required to give this heat

energy at 30% MCR = Ma Cpa t t

Hs Hc* * ( )( )

2 1

kg/hr

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FORM T10 REV - A

LHV, HHV CALCULATIONS - COAL

( ){ }14500 62000 40002 8C H S+ + 2o Higher Heating Value (HHV) = ------------------------------------------------------------- 1.8 HHV in kcal/kg { }HHV Btu lb x H W* . ( / )18 9720 11102 Lower heating value (LHV) = --------------------------------------------------- 1.8 LHV in kcal/kg Where, W is the fraction by weight of moisture in fuel and C, H2, O2 and S are fractions by

weight of carbon, hydrogen, oxygen and sulfur in the fuel.

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FORM T10 REV - A

LHV, HHV CALCULATIONS FOR GASEOUS FUEL - (NATURAL GAS)

% WT

NOTA- TION

COMPOSITION % VOL

MOL. WT

xiMixnMn /100

n= CH4, C2H6 etc i =cons for which % wt conversion to be

done

HHV (KCAL/KG)

LHV (KCAL/KG)

METHANE (CH4)

XCH4 16.043 XxnMn

CH 4 16 043100

./

n = CH4, C2H6 etc.

X1 13269.23077 11944.57716

ETHANE (C2H6) XC2H6 30.07 XxnMnC H2 6 30 07

100.

/

n = CH4, C2H6 etc.

X2 12403.24892 11353.32059

PROPANE (C3H8)

XC3H8 44.097 XxnMn

C H3 8 44 097100

./

n = CH4, C2H6 etc.

X3 12036.55041 11082.17869

I - BUTANE (C4H10)

XC4H10 58.124 XxnMn

C H4 10 58124100./

n = CH4, C2H6 etc.

X4 11811.99236 10907.78786

N-BUTANE (C4H10)

XC4H10 58.124 XxnMn

C H4 10 58124100./

n = CH4, C2H6 etc.

X5 11840.65934 10935.26039

I-PENTANE (C5H12)

XC5H12 72.151 XxnMn

C H5 12 72151100.

/

n = CH4, C5H12 etc.

X6 11698,51887 10822,98137

N - PENTANE (C5H12)

XC5H12 72.151 XxnMn

C H5 12 72151100.

/

n = CH4, C5H12 etc.

X7 11720.01911 10845.67606

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FORM T10 REV - A

NITROGEN (N2) XN2 28.013 XxnMnN 2 28 013

100./

n = CH4,C5H12 etc.

X8

HEXANE PLUS XHEX 86.169 XxnMn

HEX 86169100

./

n = CH4,C5H12 etc.

X9 11636.40767 10781.17535

Molecular weight of the gas mixture(MW)= ( )MWi YiX where, Yi = Volume fraction of gas i. MWi = Molecular weight of gas i.

Density of the gas g(lb/cu.ft) = 492 x MW x P

t359 460 14 7( ) .+

g(kg/M3) = fg(lb/cu.ft) * 16.033 where, P = gas pressure, psia t = gas temperature, F MW = gas molecular weight g = gas density, lb/cu. Ft. Higher Heating Value

of the gas (HHV) =x HHV x HHV x HHVCH C H C H1

1002

1003

1004 2 6 3 8*( ) *( ) *( )

+

+

+x HHV x HHV x HHVC H C H C H4

1005

1006

1004 10 4 10 5 12*( ) *( ) *( )

+

+

+ x HHV x HHVC H Hexane7

1009

1005 12*( ) *( )

+

plus

HHV is in kcal/kg. HHV in kcal/Nm3 = HHV(kcal/kg) x gas density (kg/m3). Lower Heating Value

of the gas (LHV) = x LHV x LHV x LHV C HCH C H1

1002

1003

1003 84 2 6*( ) *( ) *( )

+

+

+ x LHV x LHV x LHVC H C H C H4

1005

1006

1004 10 4 10 5 12*( ) *( ) *( )

+

+

+ x LHV x LHVC H7

1009

1005 12*( ) *( )

+

Hexane Plus

LHV is in kcal/kg. LHV in kcal/Nm3 = LHV (kcal/kg) x gas density (kg/m3).

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FORM T10 REV - A

STOICHIOMETRIC AIR REQUIREMENT - SOLID AND LIQUIDFUELS

CONSTI-TUENT

FRACTION

O2 REQUIRED PER KG OF

CONSTITUENT

O2 REQUIRED

PER KG OF FUEL

Carbon Xc 2.664 Xc x 2.664

Hydrogen XH2 7.937 XH2 x 7.937

Oxygen

- - -

Sulphur Xs 0.998 Xs x 0.998

Nitrogen

- - -

Moisture

- - -

Total *T * Total O2 required per kg of fuel shall be obtained by deducting the oxygen

present in the fuel. Stoichiometric dry air = O2 kg/kg of fuel (T) x 4.3196 (kg/kg of fuel fired)

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FORM T10 REV - A

STOICHIOMETRIC AIR REQUIREMENT - GASEOUS FUEL

Description

% by Vol.

Mol. Wt of comp.

% by wt (c) XiMi

XnMn / 100

Dry Air

A

B

kg/kg of comp.

D

kg/kg of gas (C/100xD)

Hydrogen (H2) 2.02 34.21

Carbon monoxide (CO)

28.01 2.46

Methane (CH4)

16.04 17.20

Ethane (C2H6) 30.07 16.06

Propane (C3H8)

44.09 15.64

I-Butane (C4H10)

58.12 15.43

N-Butane (C4H10)

58.12 15.43

I-Pentane (C5H12)

72.15 15.30

N-Pentane (C5H12)

72.15 15.30

Hexanes (C6H14)

86.17 15.21

Ethylene (C2H4)

28.05 14.75

Propylene (C3H6)

42.08 14.75

Air required / kg of gas =

( ) ( )% by wt of constituent (xi) x Dry Air kg / kg of comp.(xi)i

N

=

1

Where N is the Nth number of constituent in the gas.

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FORM T10 REV - A

RECOMMENDED FEEDWATER & BOILERWATER QUALITY FOR

POWER PLANT APPLICATION

(USING DEMINERALISED WATER)

DRUM OPERATING PRESSURE OF SL.NO. DESCRIPTION UPTO 20 BAR(g)

FEED WATER BOILER WATER 1 HARDNESS 1 - 2 pH@25 C 8.8-9.2 10.0-10.5 3 IRON,TOTAL ppm 0.05 - 4 SILICA, SiO2 ppm 1 25 5 CONDUCTIVITY

micro s/cm

10

1000 6 HYDRAZINE

RESIDUAL ppm - -

7 PHOSPHATE

RESIDUAL ppm -

20.0-40.0 8

OXYGEN max,ppm

0.02

-

9

TDS max, ppm

-

500

10

COPPER,TOTAL,ppm

0.01

-

11 SODIUM SULPHATE AS Na2 SO3 ppm

- 20-40

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FORM T10 REV - A




DRUM OPERATING PRESSURE OF SL.NO. DESCRIPTION 21-40 BAR(g)

FEED WATER BOILER WATER 1

HARDNESS

0.5

-

2

pH@25 C

8.8-9.2

10.0-10.5

3

IRON ,TOTAL ppm

0.02

-

4

SILICA, SiO2 ppm

0.3

15

5

CONDUCTIVITY micro s/cm

5

400 6

HYDRAZINE RESIDUAL ppm

-

-

7

PHOSPHATE RESIDUAL ppm

-

20.0-40.0 8

OXYGEN max,ppm

0.02

-

9

TDS max, ppm

-

200

10

COPPER,TOTAL,ppm

0.01

-

11

SODIUM SULPHATE AS Na2 SO3 ppm

-

5-10

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FORM T10 REV - A






HARDNESS

NIL

-

2

pH@25 C

8.8-9.2

9.8-10.2

3

IRON ,TOTAL ppm

0.01

-

4

SILICA, SiO2 ppm

0.1

10

5


2

300 6


0.02-0.04

-

7


-

15.0-25.0 8

OXYGEN max,ppm

0.01

-

9

TDS max, ppm

-

150

10

COPPER,TOTAL,ppm

0.01

-

11

SODIUM SULPHATE AS Na2 SO3 PPM

-

-

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FORM T10 REV - A






HARDNESS

NIL

-

2

pH@25 C

8.8-9.2

9.8-10.2

3

IRON ,TOTAL ppm

0.01

-

4

SILICA, SiO2 ppm

0.02

10

5


0.5

200 6


0.01-0.02

-

7


-

15.0-25.0 8

OXYGEN max,ppm

0.007

-

9

TDS max, ppm

-

150

10 COPPER,TOTAL,ppm

0.01

-

11

SODIUM SULPHATE AS Na2 SO3 PPM

-

-

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FORM T10 REV - A




DRUM OPERATING PRESSURE OF SL.NO. DESCRIPTION 100&ABOVE BAR(g)


HARDNESS

NIL

-

2

pH@25 C

8.8-9.2

9.4-9.7

3

IRON ,TOTAL ppm

0.01

-

4

SILICA, SiO2 ppm

0.02

*

5


0.3

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FORM T10 REV - A

FEEDWATER & BOILERWATER QUALITY FOR


(USING SOFTENED WATER)

DRUM OPERATING PRESSURE OF SL.NO. DESCRIPTION UP TO 20 BAR(g)

FEED WATER BOILER WATER 1 Iron as Fe ppm 0.100 - 2 Copper as Cu ppm 0.05 - 3 Total hardness as

CaCO3 ppm

0.300 -

4 Silica, SiO2 ppm - 150 5 Total alkalinity as CaCO3 - 700 6

Specific conductance micro s/cm

-

7000

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FORM T10 REV - A




DRUM OPERATING PRESSURE OF SL.NO. DESCRIPTION 21 - 40 BAR(g)


CaCO3 ppm

0.200 -

4 Silica, SiO2 ppm - 40 5 Total alkalinity as CaCO3 - 500 6 Specific conductance

micro s/cm -

5000

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FORM T10 REV - A






CaCO3 ppm

0.100 -


micro s/cm -

3000

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FORM T10 REV - A






CaCO3 ppm

0.050 -


micro s/cm -

2000

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FORM T10 REV - A

BOILER BLOW DOWN CALCULATIONS

DEFINITION Boiler Blowdown is defined as the process of removal of a fraction of water from boiler

unit and its replacement by feed water. This is done to prevent build up of excessive

concentration of undesirable substances in Boiler Water.

Continuous Blowdown is carried out to maintain dissolved solid concentration within

prescribed limits in the Boiler Water.

Intermediate Blowdown is carried out to reduce the sludge level in the Boiler Water

and also to accelerate the Continuous Blow down process.

E - Evaporation rate (TPH)

S - Solid content of Feed Water (g/m3)

V - Boiler Water content (m3)

C - Maximum allowable concentration of solids in Boiler Water (g/m3)

C1 - Concentration of solids in Boiler Water on completion of Intermittent

Blowdown (g/m3).

B - Actual Intermittent or Continuous Blowdown rate as percentage of Evaporation

rate.

BA - Average Intermittent Blowdown as percentage of Evaporation rate.

d - Duration of Intermittent Blowdown operation (h).

t - Interval between completion of one Blowdown operation and completion of the

next (h).

Q - Quantity of Boiler Water discharge during each Intermittent Blowdown

operation (m3).

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FORM T10 REV - A

Continuous Blowdown

C1 = C

BA = B

d = t

B = 100 x [S/(C-S)]

The above relationship is valid for various constituents of water like Alkalinity, salt

content, silica etc., Check for the Blowdown rate for each constituent separately and

the minimum value of Blowdown rate shall be considered and the corresponding

constituent shall be the governing factor. Refer document no. 100/11 for Boiler Water

limits for various drum pressure levels.

Intermittent Blowdown B = tsv x 100/[d(CV-0.5SE(t-d)-VS)] Q = EtSV/[CV-0.5SE(t-d)-VS] C1 = C - [(t-d) SE/V]

BA = Q x 100/tE

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FORM T10 REV - A

CHIMNEY SIZING

Introduction Chimneys, as we know them today, are tall slender structures which fulfill an

important function. They had a humble beginning as house hold vents and over the years, as vents grew larger and taller, they came to be known as chimneys. A cluster of them is a stack.

Function A chimney is a means by which flue gases are discharged at a high elevation so that

after dilution due to atmospheric turbulence, their concentration and that of their entrained solid particulates is with in acceptable limits on reaching the ground. A chimney achieves simultaneous reduction in concentration of a number of pollutants (such as SO2 , NOx , CO, Suspended\Particulate Matter (SPM), Respirable Particulate Matter (RPM). Size less than 10 m, lead etc) and being highly reliable it does not require a stand by, while these are its merits, it is well to remember that a chimney is not the complete solution to the problem of pollution control.

Chimney classification Chimney are classified based on their height (tall or short), number of flues (single or

multi), material of construction (Brick, RCC, steel, FRP), structural support (Guyed or self supporting), lining (Lined or unlined). When Multiflue chimney is selected ? often, a single chimney serves more than one boiler. In such a case when one of the gas sources is shut down for maintenance the gas exit velocity will reduce because of a reduction in the total volume of gases to be handled. This can lead to heavy pollution and in order to overcome this problem, a chimney serving more than one boiler can be provided with a separate flue for each gas source with such flues housed in a common enclosing concrete wind shield. These are called as Multi-flue chimneys.

Exit Velocity Flue gases emerging from a chimney experience a field of increasing wind speed,

soon a speed will be reached (termed critical wind speed) when the wind will shear off the emerging gas plume and this can lead to excessive pollutant deposition. If the exit velocity is low, it can permit cold air to flow down a part of the chimney causing acids contained in flue gases to condense on the walls and cause damage. In order to avoid this, the flue gas velocity (ie. when chimney is operating in part load) should be such that 1.5 times the wind velocity.

A part from this, a larger exit velocity will result in higher plume rise which in turn will

lead to a diminished GLC of pollutants. For the above reasons, a high exit velocity is preferred but this can damage the lining due to erosion. With steel liners, velocities upto 45 m/s can be used and with brick liners velocities higher than 30 m/s is not recommended.

For power plant chimneys handling more than 2000 M3 /min of flue gases, exit

velocities will be in the range of 20-25 m/s. In general for our calculations purpose we use flue gas velocity as 1.5 times the

wind velocity, which is recommended in IS 4998 and Tall chimneys by S.N Manohar.

FICHTNER India



FORM T10 REV - A

Physical Dimensions Shape Any shape for the chimney, other than circular, offers greater resistance to wind

currents and is more prone to oscillation. Hence circular shape is recommended. Exit size The top dimensions of a flue are fixed such that a given volume of gases can be

discharged at the design exit velocity. A 20% increase in the cross sectional area shall be provided for the effect of reduced velocity near the inner surface of the chimney due to friction. If a chimney has to handle a range of gas volumes, then the exit velocity should be high at minimum load and at the same time should not exceed the limiting values when operating at full load.

Physical height The following two consideration dictate the physical height of a chimney. 1. To generate a draft which will cause gases to flow out with the desired exit velocity. 2. To satisfy local regulations in respect of permissible GLC of Pollutants. CHIMNEY SIZING CRITERIA Step : 1 Chimney height based on IS: 4998 (Part-I) 1975.

Height of the chimney `H = AQFK

Cn

V TP

1 2 1 6/

*/

where A = a coefficient depending upon the atmospheric vertical temperature distribution

which determines the condition for vertical and horizontal dispersion of the substances in air. these value for Indian condition may be taken as 200.

Q = total emission of impurities from all chimneys (mg/s) F = a coefficient to account for the substances settling velocity in the atmosphere.

This value may be taken as 1 for SO2 , since the settling velocity of SO2 is nearly zero ; and 2 for dust if the average practical dust collecting efficiency is not less then 90 percent and 2.5 if the efficiency is less then 90% percent.

K = a coefficient accounting for the effect of flue gas exit velocity for the chimney

Vo . The values are given below. Flue gas Exit Velocity

Vo m/s Value of K

10-15

1

FICHTNER India



FORM T10 REV - A

20-25 0.9

30-35

0.8 Cp = Maximum expected concentration of the pollutant at grade level (mg/M3 ) n = Number of chimneys V = Total volume of flue gases discharged from chimneys (M3 /s ) T = Temperature difference between flue gas Tg and ambient air temperature Ta (C) = Tg - Ta Step - 2 If background pollution is already in existence in the area under consideration, the

chimney height calculated shall be modified as follows.

Hc = H C

C Cp

p e

1 2/

Where Hc = corrected chimney height in (m) Ce = existing background concentration in (Mg/m3 ) Step - 3 CHIMNEY HEIGHT AS PER POLLUTION CONTROL BOARD NORMS. However, as per pollution control norms the stack height requirement for sulphur di-

oxide control shall be as follows. H = 14 (Q)0.3 Where H = Chimney height (m) Q = SO2 emission rate (kg/hr) Chimney height calculated based on the above two methods has to be compared, and

the tallest one shall be selected. Stack height requirement as per pollution control norms for larger capacity power

plants is as follows. For Boiler size less than 200 MW above steps shall be followed, if Boiler size is above 200 MW & less then 500 MW then 220 M height chimney shall be selected if the Boiler size is more than 500 MW then 275 M height chimney shall be selected.

Step - 4

FICHTNER India



FORM T10 REV - A

CHIMNEY DIAMETER Chimney diameter at the exit shall be calculated as given below

De =4

0

VV

Where De = diameter at exit (m) V = total volume of flue gas (M3 /sec) V0 = allowable velocity at the exit (M/Sec.) ie. 1.5 x wind speed. As explained earlier the calculated diameter has to be increased by 20% Dec = 1.2 x De Where Dec = corrected diameter at the exit. Stack Draft Calculations :- After finishing the above calculation, stack draft calculation shall be done and draft

available shall be checked. The following are the procedure to calculate the net draft available.

Net draft available is nothing but theoretical draft calculated less the dynamic head

loss due to kinetic energy of gases leaving a chimney and the head lost in overcoming friction along the internal surface of a flue.

Net draft = theoretical draft - (Dynamic loss + Friction loss).

Net draft = 13.6 * 0.029 BHd 1 1

T V T Va a g g

15.4x10-9 x Q2 g x Vg H fT

B DT

B DT

BeDd

gm

m m

gt

E t

ge

e5 4 4+

MM of H2O

where B = Barometer pressure (mm of Hg) Hd = height of chimney above breeching (m) Ta = air temperature ( K) Va = Sp. volume of air at STP = 0.775 (m3/kg) Tg = Temperature of flue gas ( K) Vg = Sp. volume of flue gas at STP (m3 /kg) Qg = Mass emission rate of flue gas (g/sec)

FICHTNER India



FORM T10 REV - A

f = friction factor (refer enclosed chart) Tgm = Temp of flue gas at mean height (k) Bm = Barometric pressure at Mean height (mm of Hg) Dm = Diameter of chimney at mean height (m) Tgt = Temperature of flue gas at top of chimney ( K) Bt = Barometric pressure at top (mm of Hg) Dt = Diameter of chimney at top (m) Tge = Temperature of flue gas at breeching level (m) Be = Barometric pressure at breeching level (mm of Hg) De = Diameter of chimney at breeching level (m) Clearances The following clearances has to be obtained for installing a chimney 1. Stack height clearance from National Air port Authority 2. Environmental clearance from state pollution control board and from Ministry of

Environment & Forest, Government of India.

FICHTNER India



FORM T10 REV - A

EMISSION/AMBIENT AIR QUALITY CALCULATIONS

PARTICULATE EMISSION LEVELS Particulate emission data are needed to size dust collectors for coal-fired boilers. In

coal-fired boilers, about 75% of the ash is carried away by the flue gases and 25% drops into the ash pit. The following expression may be used for determining the Ash concentration in the flue gas.

Ca = 2,40,000 x (% ash/100) ------------------------------------------------------------------ T x [7.6 x 10-6 x HHV x (100+E) + 1 - (% ash/100)] Where Ca = ash concentration, grains / cu.ft E = excess air % T = gas temperature, OR HHV = Higher Heating value, Btu/lb To convert ash concentration in grains/cu.ft to kg/m3 Ca = 0.01 x A x 7000 x Ash concentration in lb/ft3 = Ca ---- 70 Ash concentration (kg/m3) = Ca ---- * 16.033 70 = gas density, lb/Cu.ft = 39.5 / (460+t) t = gas temperature , F Ca = ash content, grains/acf or grains/scf depending on whether density is computed at actual temperature or at 60F A = ash content, % by weight The expression for density is based on atmospheric flue gases having molecular

weight of 28.8 The ESP is sized to achieve an outlet dust concentration of 150 mg/Nm3

FICHTNER India



FORM T10 REV - A

SO2 Emission LEVEL Emission of S02 in lb/mmBtu (e) = 2 x 104 S ------- HHV Where S is the % sulfur in the fuel. HHV = Higher Heating value of the fuel Btu/lb Conversion S02 Emission rate in lb/mmBtu to PPM Weight flow rate of flue gas produced / MMBtu Wg = 106 + (1+%E)*A HHV 100 Air/MMBtu of fuel (A) = 760 for Bituminous coals = 745-750 for furnace oil and lignite = 780 for Anthracite = 800 for coke Moles of flue gas = Wg ; Mf : Molecular weight of flue gas (mf) Mf Moles of SO2 = e MSO2 : Molecular weight of SO2 --- (MSO2) = MSO2 (SO2) in ppm = M SO2 x 106 --------- Mf NOX in Volumetric Units on dry Basis 100 * (w/46) (W/Mw) Vn(ppmvd) = 100-%H2O --------- (1) where %H2O = Volume of water vapour MW = Molecular weight of the Exhaust Gases M = Flow rate of NO2, lb/hr W = Turbine Exhaust Gas Flow, lb/hr The value of V obtained with Eq-1 must be converted to 15% Oxygen on dry basis to

give ppmvd of Nox at 15% O2 . V * (21-15) * 166 Vn(ppmvd 15% 02) = 21 - 100%02/(100-%H2O) ------- (2) = V * F where %O2 = Oxygen present in the wet exhaust gases. Factor F converts V to 15%

Oxygen basis, which is the usual basis for reporting emissions.

FICHTNER India



FORM T10 REV - A

Co-Emission in ppmvd Vc = 1.642 * Vn (for the same Wlb/hr rate) Because the ratio of Molecular weights of NO2 and Co is 1.642. NOISE EMISSION LEVELS NOISE LEVEL LIMITATIONS 1. NOISE LEVEL LIMITATIONS AROUND EQUIPMENTS During normal operating conditions (70% load to 100% load), the noise level

around the equipments shall not exceed 90 db (A) measured at a distance of 1 m from the nearest surface of the machine and at a height of 1.2 m from the floor level.

2. NOISE LEVEL LIMITATIONS AT THE CONTROL PROPERTY BOUNDARY The noise level at the Control property boundary shall be limited to the values

as given in the table below:- Ambient Air quality standards in respect of Noise

AREA CODE

CATEGORY OF AREA

LIMITS IN DB(A)

DAY- TIME

NIGHT TIME

A. Industrial area 75 70 B. Commercial area 65 55 C. Residential area 55 45 D. Silence area 50 40

Day time is between 6 a.m to 9 p.m Night time is between 9 p.m to 6 a.m The noise levels at the property boundary line shall be specified as per the above

table which should remain within the prescribed limits throughout the plant operating range (i.e) 70% load to 100% load. It is to be noted that the noise limit is for total noise (background noise + plant noise)

FICHTNER India



FORM T10 REV - A

NOISE LEVEL MEASUREMENT AROUND EQUIPMENTS The noise level limitations as stipulated in the above table shall be demonstrated

around the following equipments:

1. Gas Turbine 2. Steam Turbine 3. Circulating Water Pumps 4. Boiler Feed pumps 5. Condensate Extraction pumps 6. Steam Jet air Ejectors 7. Pulverising Mills 8. F.D fans, I.D fans & P.A. fans

For equipments inside the building, the noise monitoring should be done for 8 hours

continuously as the worker is exposed to the noise of 8 hours during a shift. The noise limits for industrial workers has been prescribed as 90dB(A)

Noise measurements should be done on the prescribed paths. After carrying out the

pilot survey, detailed baseline noise data should be collected. These should be atleast four key measuring points which depend upon the size of the machine and the symmetry of the acoustic radiation. The noize measurement should be done at 4 key measuring points and successive measuring locations. The successive measuring locations should be on the prescribed path at intervals of not more than 1 meter commencing from the 4 key measuring points.

EXCLUSIONS Noise levels during plant transients, upset conditions and noise levels resulting from

the actuation of safety devices may exceed the limits specified for a short period of time.

FICHTNER India



FORM T10 REV - A

MONITORING OF NOISE The monitoring of noise shall be done inaccordance with the following IS standards.

IS 4758 : 1968 Methods of Measurement of noise emitted by machines

IS 6098 : 1971 Methods of Measurement of air borne noise emitted by rotating electrical machinery

IS 7194 : 1973 Assessment of noise exposure during work for hearing conservation purposes

IS 9779 : 1981 Sound level meters (superseding IS:3931 - 1966) and (IS 3932 - 1966)

IS 9989 : 1981 Assessment of noise with respect to community response

IS 10423 : 1982 Personal sound exposure meter.

IS 10534 : 1983 Methods of measurement of airborne noise emitted by gas turbine installations

IS 9876 : 1981 Guide to measurement of airborne acoustical noise and evaluation of its effect on man.

FICHTNER India

DOC. NO. WI-ME-DSN-103-001 REV. NO. R-1 PAGE 1 OF 8


FORM T10 REV - A

ASH HANDLING SYSTEM

1.0.0 Introduction

This document is a guide line applied to ash handling facilities for solid fuel fired

steam generators, extending from ash collection points of the combustion residues

upto the places of dispatch from the power station area.

1.1.0 Fuel Used & Ash Content

The fuels normally considered are solid fuels like coal/lignite/washery middlings etc.

When other fuels are used appropriate considerations are to be made. A decisive

influence on the properties of ash is exerted by the physical, chemical and

technological conditions of combustion. Generally either fluidized bed furnaces or

pulverised coal fired furnaces are adopted depending on the generating capacity of

the plant. Normally it is considered that for coal the total ash percentage will be about

45% and for lignite about .....% for designing the ash handling system. The correct

data shall be obtained from the design spec for fuel.

2.0.0 Type of ash generation

The type of ash produced due to burning of solid fuel such as coal/lignite is Bed ash /

Bottom ash, Cyclone ash and fly ash. The bed / bottom ash is a coarse ash

discharged from the boiler bed area or furnace hopper. Normally the quantity of bed

ash is about 20% of total ash content of the fuel. The density of bed ash is about 800

to 1100 kg/m3 . The average particle size range is 1.0 to 10mm and maximum is

30mm. The fly ash is entrained in the flue gas and collected in the Economiser / Air

preheater hoppers, downstream electrostatic precipitator hoppers and in the chimney

ash hopper. Normally the quantity of fly ash is about 80% of total ash content of the

fuel. The density of fly ash is about 500 to 900 kg/m3 . The average particle size

range is 0.1 to 3.0 mm. Maximum is 10 mm.

The ash handling system is distinguished according to the type of ash such as.

- Coarse ash or granulate

- fly ash.

3.0.0 Ash handling systems

FICHTNER India



FORM T10 REV - A

The ash handling systems are classified as

- Mechanical conveying systems

- Hydraulic conveying systems

- Pneumatic conveying systems

The mechanical conveying systems generally consists of

- Submerged scrapper conveyors

- Belt conveyors

Hydraulic conveying system uses water as a conveying medium. The system

consists of pumps, ejectors, sluiceways and conveying pipelines.

Pneumatic conveying systems are specifically used for collection points where dust is

obtained. The system uses air as the conveying medium.

3.1.0 Mechanical Conveying Systems

Submerged scrapper conveyors are provided below the combustion chambers of

boilers and are used for the quenching and discharge of the bed ash discharged. The

scrappers are generally spaced at 0.5 to 1.0m between two endless chains at the

bottom of a water filled through and operate at low speed at about 0.3 to 1m/min

before discharge.

The boiler outlet is sealed off by means of a submerged chute immersing in the water

bath. Boiler downward expansion must be considered in the immersion depth. The

maximum cooling water outlet temperature shall not exceed 50C. Depending on the

water temperature difference the required amount of water is about 6 to 20 times of

the amount of ash generated. The drainage water is polluted with fine ash and hence

the overflow / drain pipe shall be adequately sized and necessary down stream

classifying equipment is installed.

Belt conveyors are provided when longer distance conveying is required. Care must

be taken to ensure that sufficiently cool bed ash is conveyed. Maximum inclinet of

belt conveyor is limited to 16.

3.2.0 Hydraulic conveying systems

FICHTNER India



FORM T10 REV - A

3.2.1 The hydraulic handling system of ash consists of slurry pumps. Ejectors, sluiceways,

sump etc. The bottom ash collected is normally stored in a water impounded ash

hopper for 8hrs. Then the ash is crushed to a handling particle size of maximum

50mm and pumped to disposal site by slurry pumps. Because of high heat dissipation

rate water must be fed in continuously as the water temperature is limited to 60C.

The water impounded hopper is a steel shell with a temperature resistant lining on the

inside.

3.2.2 The slurry pumps used for conveying are normally of single stage non-clog centrifugal

pumps having a maximum speed of 1000 rpm for transport distance upto 3 km.

(horizontal). When the distance is more 2 to 3 pumps are connected in series or

intermediate pump stations are provided.

3.2.3 Ejectors

When Ejectors are used ash to water ratio is 1:4 to 1:10 depending on the ash size,

feeding configuration. The necessary water pressure upstream is about 6 to 8 times

the pressure in the delivery piping after the ejector. This pressure level depends on

ejector efficiency, delivery length, delivery head and piping resistance. Ejectors are

simple in design, replacement is easy and less maintenance compared to slurry

pumps. Ejector system is normally adapted for fly ash conveying.

Sluiceways conveyance is adapted for bed ash / coarse ash. Sluiceways are suitable

only for short distance up to the slurry sump from where the ash slurry is conveyed by

pumps. The slope of sluiceway is about 2 to 3% and water requirement is about 20

times the ash handled.

3.3.0 Pneumatic Conveying Systems

In Pneumatic conveying systems the ash is discharged by means of compressed air

either directly from the hoppers or from a collecting vessel and conveyed to the silos

through piping. The piping resistance is over come by conveying air pressure. Two

types of pneumatic conveying systems are

- dilute phase conveying and

- dense phase conveying

Advantages of pneumatic systems are

FICHTNER India



FORM T10 REV - A

a) Long distance conveying so that storage can be located for off from the plant.

b) Ash can be conveyed directly from multiple hoppers to the disposal point.

c) Higher conveying capacity over longer distances.

Hence medium capacity powerstations normally select pneumatic systems.

The system components are

1) Conveying pipe line with required fittings.

2) Positive displacement air supply blower or compressor.

3) Pressure feeders attached to the collection hoppers to feed into the conveying

pipe. 4) Storage bin.

5) Silo unloading systems.

3.3.1 Lean Phase Conveying

In Dilute phase / lean phase conveying system the gas velocities are much greater

than the settling velocity of the individual grain.

The velocity of conveying air in lean phase is about 15 m/sec to 20 m/sec at a mass

flow ratio about 10 and pressure loss is about 0.1 to 1 bar/100m. The particle velocity

is about 0.9-1 m/sec.

3.3.2 Dense Phase Conveying

In dense phase conveying the velocity of conveying is low but higher pressure is used

where the material to be transported completely fills the pipe and transported in

separate plugs.

The velocity of coveying air in dense phase is 1 to 10m/s with mass flow ratio 20 to

150 and the pressure loss is about 0.5 to 1 bar/100m. The particle velocity is 0.5 to

0.9 m/sec.

3.3.3 System description

3.3.1 Dense phase conveying system

FICHTNER India



FORM T10 REV - A

The system envisages removal of fly ash/bedash pneumatically by means of pressure

conveying system. Fly ash would be collected in various hoppers located in flue gas

path viz. economiser, air preheater, ESP and the chimney hopper which amount to a

maximum of 80% of total ash produced in the furnace. Bed ash will be collected from

the bed ash discharge points after necessary cooling by the bed ash coolers or water

cooled hoppers which amount to 20% of total ash generated.

The bedash / flyash collected would be fed into the individual transmitter vessel

located below the hoppers. At each hopper level probe shall be provided for initiating

the conveying cycle. The system can operated both in level / timer mode. The ash

collecting surge hopper shall be provided with water cooling arrangement whenever

hotash (generally for / bedash / cycloneash) is handled. The isolation seal valves are

also water cooled.

The operation of the system is fully automatic. When the system is operated in auto -

timer mode the system shall have continuous cycle after a preset interval of time. In

level mode level prope provided in the surge hopper shall initiate the conveying cycle.

The isolation valve shall open and allow ash by gravity into the transmitter vessel by

gravity till it is closed automatically by the timer preset as per process parameters. On

closure of the isolation valve. The valve seal gets inflated and the conveying air is

injected into the vessel. The vessel is pressurised and the material resistance helps

pressure build up which conveys the material to the destination silo. When conveying

is complete the pressure drop down to nearly atmospheric pressure and is sensed by

the control system, the air supply to the system is stopped. The transmitter vessel is

ready for the next cycle.

Ash is conveyed by M.S ERW pipes conforming to is............ heavy grade with long

radius allow CI bends upto the terminal box located on top of the silo. The terminal

box help the ash to be discharged into the silo. The conveying air escapes by the

vent provided on top of the silo. The vent is provided with reverse pulsejet type bag

filter to filter the vent air. The size of the ash silo is depending upon the quantity of

ash generated and the silo discharging operation cycle.

The ash conveying pipe line should have minimum number of bends as far as

possible to avoid choking of the line and reduce maintenance problems. The bends

should have long radius about 10 D of the pipe dia.

Incase two or more silos are to be used for collecting the ash from single line

pneumaticaly operated divertor valves are used to divert the ash to the required silo.

FICHTNER India



FORM T10 REV - A

3.3.2 The lean phase conveying system also functions similar to the dense phase system

only with the difference of high volume air supply source at low pressure.

The general system configurations are enclosed in the Annexure -1.

FICHTNER India



FORM T10 REV - A

FICHTNER India



FORM T10 REV - A

RAW WATER ANALYSIS CONVERSION FACTORS FOR IONIC LOADS

Raw Water contains impurities which can be classified as Suspended Solids and

Dissolved Solids. Suspended solids can be removed by Filtration. The Dissolved

Solids can be removed only by Distillation, Reverse osmosis and Ion Exchange

process.

The constituents of Dissolved solids are salts of Calcium, Magnesium, Sodium and

Potassium existing in the form of CaCO3, MgCO3, CaSO4, Na2, SO4, etc.

The most popularly used scale for measurement of Ionic load is mg/l or Parts Per

Million (PPM). The constituents are measured on the basis of As CaCO3 or As

such. The actual load of constituent Ion measured on As such basis are converted

to As CaCO3 basis by multiplying the PPM As such by the factor Atomic weight of

constituent / Atomic weight of CaCO3. Atomic weight of CaCO3 is 100.

It is imperative to convert all Ionic loads to As CaCO3. Basis in order to check for

Ionic balance. Ionic balance is achieved if total Cation load is equal to total Anion load.

Another scale for measurement of Ionic load is Equivalent Mass/I (Eq.m/l). The

Equivalent Mass of given substance is the quantity of the substance that will combine

with or replace in a given reaction one atom of Hydrogen (or another monovalent

element as the amount of the substance corresponding to the transition of one

electron (in oxidising reducing reactions).

Eq = M/n.

But this scale is not used extensively because the equivalent of many chemical

compositions is not constant as it depends on the type of reaction involved.

The multiplication factors for conversion of Ionic load from AS SUCH to AS CaCO3

are as follows:

FICHTNER India



FORM T10 REV - A

SL.NO. IONS MULTIPLICATION FACTOR

1. Calcium (Ca++) 2.50 2. Magnesium (Mg++) 4.10 3. Sodium (Na+) 2.18 4. Potassium (K+) 1.28 5. Sulphur (S++) 3.13 6. Aluminium (Al+) 5.58 7. Fluorine (F+) 2.56 8. Bicarbonates (HCO3) 0.82 9. Sulphates (SO4) 1.04 10. Chloride (CI) 1.41 11. Nitrate (NO2) 0.81 12. Iron (Fe) 0.79 13. Silica (Si) 0.83 Sl.No.1 to 7 gives the Cation part and Sl.No.8 to Sl.No.11 indicates the Anion part.

Total cationic load shall be equal to Total anionic load which is called ionic balance.

Add the Cation load, Anion load, Iron and Silica in AS SUCH basis to obtain Total

Dissolved Solids (TDS).

FICHTNER India



FORM T10 REV - A

RAW WATER ANALYSIS

Raw water available at the site shall be analysed in a laboratory and its physical,

chemical and Bacteriological Characteristics shall be furnished as per the format

given below. These data shall be obtained for four seasons over one year. To work

out the seasonal average water analysis over a period of atleast 3 years shall be

made available.

These details are important to decide the treatment scheme for the raw water to make

it suitable for the end user.

Source of water 1. Bore Well 2. Open Well 3. River 4. Sea 5. Others Physical Characteristics 1. Colour 2. Taste 3. Odour 4. Temperature (C)

Chemical characteristics

1. Ph

2. Specific conductance (micro siemens / cm)

3. Turbidity (NTU)

4. Total Dissolved solids in ppm

5. Total Suspended Solids in ppm

6. Total Alkalinity as CaCO3 in ppm

7. Bicarbonates as HCO3 in ppm

8. Calcium as CaCO3 in ppm

9. Magnesium as CaCO3 in ppm

11. Sodium as CaCO3 in ppm

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FORM T10 REV - A

12. Potassium as CaCO3 in ppm

13. Chlorides as CaCO3 in ppm

14. Sulphates as CaCO3 in ppm

15. Fluorides as CaCO3 in ppm

16. Total Phosphorus As P in ppm

17. Nitrates as CaCO3 in ppm

18. Nitrites as CaCO3 in ppm

19. Ammonical Nitrogen As NH3-N

20. Total Chlorine As Cl2 in ppm

21. Bromides As Br in ppm

22. Oil & Grease in ppm

23. Total Cyanides As CN in ppm

24. Phosphates as CaCO3 in ppm

25. Dissolved Oxygen in ppm

26. Chemical Oxygen Demand in ppm

27. Biochemical Oxygen Demand (for 5

days at 20C)

in ppm

28. Total Organic Carbon in ppm

29. Total Silica as SiO2 in ppm

30. Reactive Silica as SiO2 in ppm

31. Colloidal Silica as SiO2 in ppm

32. Total Iron as Fe in ppm

33. Dissolved Iron as Fe in ppm

34. Total Manganese as Min in ppm

35. Dissolved Manganese as Min in ppm

36. Total Lead as Pb in ppm

37. Total Cadmium as Cd in ppm

38. Total Copper as Cu in ppm

39. Total Strontium as Sr in ppm

40. Total Barium as Ba in ppm

41. Total Aluminium as Al in ppm

42. Total Lithium as Li in ppm

43. Total Zinc as Zn in ppm

44. Total Nickel as Ni in ppm

45. Total Selenium as Se in ppm

46. Total Tin as Sn in ppm

47. Total Mercury as Hg in ppm

FICHTNER India



FORM T10 REV - A

48. Total Cobalt as Co in ppm

49. Total Arsenic as As in ppm

50. Total Chromium as Cr in ppm

51. Silt Density Index

Bacteriological Characteristics

1. Aerobic bacterial plate count at 37C

(72 hrs)

as CFU per ml

2. Total Faecal Coliform count, as Most

Propable Number (MPN) per 100 ml

as CFU per ml

3. Total E. Coli bacteria in

100 ml

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FORM T10 REV - A

COOLING TOWER BLOW DOWN, EVAPORATION & DRIFT LOSS CALCULATIONS

DEFINITION The Circulating Water of the Cooling Water System gains heat in the Condenser &

other Auxiliaries and rejects the same in the Cooling Tower. In the Cooling Tower the

spray of water comes in contact with air. A part of the Water is evaporated and the

remaining water is cooled. The latent heat for evaporating a part of Water is obtained

from the balance water which is getting cooled.

In the Cooling Water System Water loss takes place in three different ways.

1. Evaporation loss

2. Blowdown loss

3. Drift loss

Evaporation loss

A part of Water evaporated in order to cool the remaining Water is Evaporation loss.

Evaporation loss is calculated by the relation

E = T/6.11

E - Evaporation loss in %

T - Temperature of Cooling in the tower. (Difference between Inlet & Outlet Temp.)

Drift Loss

Drift loss is the loss of Water in the Cooling Tower by entertainment of Water particles

along with the Water vapour. Drift eliminators are installed in the Cooling Tower to

minimise the Drift loss. Normally Drift loss is in the range of 0.1% to 0.2% of System

flowrate.

FICHTNER India



FORM T10 REV - A

Blowdown loss

The Water which is evaporated does not carry any dissolved solids with it. The

dissolved solids are getting concentrated in the Bulk Water. Over a period of time, the

Concentration levels reaches a limit above which the solids tend to precipitate and

form scales on the pipes and heat transfer surfaces. The process of removing

calculated quantity of Water and adding fresh Water in order to maintain the

concentration levels of dissolved solids below prescribed limits to avoid Scaling is

called as Blowdown. Blowdown is calculated as

B = [E/(C-1)] - D

Where B - Blowdown loss %

D - Drift loss %

C - Cycle of concentration

Cycle of concentration (COC) is determined based on the Scaling/Corrosion

behaviour of circulating water. Refer Document No.108/2 for calculation of Scaling

Index and Cycle Of Concentration.

Make up of Losses

The losses in the Cooling Water System due to Evaporation, Drift and Blowdown has

to be made up using fresh Water. The quantity of fresh Water make up is addition of

all the losses put together.

M = E + B + D

= E + {[E/(C-1)] - D} + D

= E + E/(C-1)

M = EC/(C-1)

M - Makeup quantity % of total flow

E - Evaporation loss % of total flow

C - Cycle of concentration.

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C:\Siva\REFERENCES\USEFUL BOOKS\DESIGN GUIDE-

FICHTNER\WI-ME-DSN-123-001.doc FORM T10 REV - A

DIFFERENCE BETWEEN HORIZONTAL PUMPS & VERTICAL PUMPS

Introduction A pump is defined as a device which raises or transfers fluids. Pumps may be classified on the basis of the applications they serve, the materials from

which they are constructed, the liquid they handle, and even their orientation in space. All such classifications, however, are limited in scope and tend to substantially overlap each offer.

All pumps may be divided into two major categories. 1. Dynamic. 2. Displacement. Dynamic : In which energy is continuously added to increase the fluid velocities within the

machine to values in excess of those occurring at the discharge such that subsequent velocity reduction within or beyond the pump produces a pressure increase.

Displacement : In which energy is periodically added by application of force to one or more

movable boundaries of any desired number of enclosed, fluid- containing volumes, resulting in direct increase in pressure upto the value required to move the fluid through valves or parts into the discharge line.

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PUMPS

DISPLACEMENT DYNAMIC

CENTRIFUGAL

AXIAL FLOW

SINGLE FLOW

MULTISTAGE

CLOSED IMPELLER

OPEN IMPELLER

MIXED FLOW RADIAL FLOW

SINGLE SUCTION

DOUBLE SUCTION

SELF PRIMING

NON PRIMING

SINGLE STAGE

MULTI STAGE

OPEN IMPELLER

SEMI-OPEN IMPELLER

CLOSED IMPELLER

PERIPHERAL

SINGLE STAGE

MULTI STAGE

SELF - PRIMING

NON - PRIMING

SPECIAL TYPE

JET REDUCTOR

GAS LIFT

HYDRAULIC RAM

ELECTROMAGNETIC

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PUMPS PUMPS

DYNAMIC DISPLACEMENT DISPLACEMENT

RECIPROCATING RECIPROCATING

PISTON PLUNGER PISTON PLUNGER

STEAM-DOUBLE ACTING SIMPLEX

DUPLEX

POWER SINGLE ACTING DOUBLE ACTING

SIMPLEX DUPLEX

TRIPLEX MULTIPLEX DIAPHRAGM

SIMPLEX

MULTIPLE

FLUID OPERATED

MECHANICALLY OPERATED

ROTARY

SINGLE ROTOR

VANE

PISTON

FLEXIBLE MEMBER

SCREW

PERISTALTIC

MULTIPLE ROTOR

GEAR

LOBE

CIRCUMFERENTIAL PISTON

SCREW

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Some of the factors that influence the selection of a pump follow. 1. Liquid to be handled. a. Quantity and pressure. b. Viscosity of the liquid at the pumping temperature. c. Relation of the suction pressure at the pumping temperature to the

vapour pressure. d. Is the liquid corrosive. e. Is the liquid abrasive (does it contain solids). f. Are undissolved gases present. 2. Requirements. a. Must the pump meter as well as raise or transfer. b. Must the pump supply a variable quantity in response to process needs. c. Will there always be liquid for the pump to handle. d. Is filterability a problem. 3. Sealing a. Solvents (leaching of lubricant). b. Solids (abrasion of packing or seals . c. Toxicity. d. Flammable vapors. e. In compatibility with ambient condition. f. Loss of expensive fluids. 4. Safety a. Material of construction to avoid fire hazard. b. Pressure protection (particularly solids) 5. Size and position. a. How much space is available. b. Where must the pump be located. 6. Scale - up problems. 7. Standardisation (with other types and makes already installed) GENERAL FEATURES OF CENTRIFUGAL PUMPS Centrifugal pumps accomplish the generation of pressure by the conversion of velocity

head in to static head. The rotary motion of impellers adds energy to the service fluid in the form of a velocity increase. This velocity increase is converted into static head in the volute diffusing section of the casing. A pump operating at a fixed speed will develop the same theoretical head in metre of flowing fluid, regardless of density. However, the pressure corresponding to the developed head (in bar) depends on the fluid density.

The parameters that establish the maximum head (in metre of fluid) that a centrifugal

pump can develop are the pump speed (rpm), impeller diameter, and the number of

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impellers in series combination. Impeller design and blade angle mainly affect the slope and shape of the head - capacity curve and normally have no or little effects on the developed head.

Normal and maximum viscosity ranges are a major consideration in pump selection

because of possible deterioration in performance with increasing viscosity. Deterioration can be both continuous and gradual. The table can serve as a guide in selecting the proper centrifugal pump type for an application.

VISCOSITY SENSITIVITY OF DIFFERENT PUMP TYPES

KINEMATIC VISCOSITY GUIDELINES TYPE PUMP U = /P (mm2/sec) Rotary 7 Nominal minimum viscosity for rotory

pumps. Efficiency begins to decrease as viscosity increases viscosity should be specified for services when it exceeds this level.

Centrifugal

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Specially designed centrifugal pumps are self-priming. One type accomplishes evacuation of the suction line vapour by entertainment of vapour bubbles from the suction side of the impeller in a charge of liquid held in the pump casing. The liquid charge in recirculated to the suction side after separating the entrained vapour.

Most centrifugal pumps have a self-venting feature small amounts of vapour trapped

within the casing at start-up (after suction, priming in complete) are swept out into the discharge line when the pump is started. Horizontally split casings are not arranged to be self-venting, however, and are equipped with specially designed valved vent connections requiring manual operation. single-stage centrifugal pumps with top discharge connections have good self-venting performance eventhough the casing shape places a small high - point vapour pocket in the top of the discharge volute.

CONSTRUCTION FEATURES OF CENTRIFUGAL PUMPS There are a variety of design features applied to the different construction styles of

centrifugal pumps. A summary of the main features follows. Volutes and Diffusers Pump have diverging channels called volutes which are cast into the discharge zone of

the casing. This casing section collects the liquid discharged by the impeller and converts velocity energy into the pressure energy. A centrifugal pump volute increases in area from its initial point until it encompasses the full 360 around the impeller and then flares out to the final discharge opening. Single-valves passages are simple type of design causes an unbalanced load on the impeller because of the variation in pressure around the periphery when the pump is operated at capacities other than design condition. Double - volute configurations are employed when the unbalanced force level threaten to cause significant shaft deflection. Twin/Double Volute design consists of two 180 volutes a passage external to the second joins the two into a common discharge.

Vaned diffusers for pressure conversion offer the advantages of balanced radial force,

compact size, and peak efficiency at high head and low flow. But they are more difficult to fabricate and repair than volute pumps.

IMPELLER Common impellers are enclosed with full discs and shrouds Semi open impellers have a full back disc but no front shrouds Fully open impellers have vanes but little or no disc material. They are employed

accordingly in low - head, solids - handling service. Impeller can be clasified by the shape, and form of their vanes. 1. Straight vane impeller : The vane surfaces are generated by straight lines parallel to the axis of rotation.

These are also called single curvature vane. 2. Francis - vane impeller : The vane surfaces of francis - vane impeller have double curvature lower

specific speeds less than 4200 are called francis vane impeller.

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3. Mixed flow impeller : An impeller design that has both a radial and axial flow components is called a

mixed-flow impeller. It is generally resticated to single - suction design with a specific speed above 4200.

4. Propeller or axial flow impeller : Mixed flow impellers with a very small radial flow components are usually

referred to as propellers. In a true propeller or axial-flow impeller the flow strictly parallels to the axis of rotation.

Further the impeller can be clasified into (a) Single - suction impeller (b) Double suction

impeller In a single-suction impeller, the liquid enters the suction eye on one side only. As a

double-suction impeller, the liquid enters the impeller simultaneously from both sides. Wearing Rings Wearings are generally fitted at the close - clearance position in the pump casing and at

an apposing position on the impeller, which allows easy restoration of the design clearnace to separate the discharge pressure zone of the pump from the suction pressure areas and to minimise back leakage. Many high - pressure centrifugal pumps are fitted with wearing rings at the back sides (disc) of the impeller. This reduces the thrust force on the impeller, at the same time minimizing the stiffing box pressure.

Nozzles Many horizantal pumps all provided with suction and discharge nozzles on the top of the

casings. In some horizontal pumps, suction nozzles are located at the end of the pump co-axial with the shaft centre line. In horizontally split pumps positioning of the nozzles in the bottom half of the casing so that the bottom half does not have to be disturbed during maintenance.

Stuffing boxes Stuffing boxes have the primary function of protecting the pump against leakage at the

point where the shaft passes out through the pump casing. If the pump handles a suction lift and the pressure at the interior stuffing box end is below atmospheric, the stuffing box function is to prevent air leakage in to the pump. If this pressure above atmospheric, the function is to prevent liquid leakage out of the pump. Conventional stuffing boxes are filled with either packing material, such as braided rope or with a mechanical shaft seal.

Bearings The function of bearings in the centrifugal pumps is to keep the shaft or rotor in correct

alignment with the stationary parts under the action of radial and transverse loads. Those that give radial positioning to the rotor are known as line bearings, where as those that locate the rotor axially are called thrust bearings. All types of bearings have been used in centrifugal pumps.

DIFFERENCE BETWEEN HORIZONTAL PUMPS & VERTICAL PUMPS

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HORIZONTAL VERTICAL

1 Shaft orientation is horizontal (ex.) End suction, Horizontal split

Shaft orientation is vertical (ex.) vertical turbine pump, vertical condensate pump etc.

2 Pump supported by casing & foot support

Pump supported by suspended column

3 Location of suction nozzle can be end, side, bottom or top suction

Only bottom suction is possible.

4 Occupies more floor space

Less floor space is requried

5 Mechanical cost :

Cost of pump-motor set is low Cost of pump-motor set is high (2 to 3 times)

Installation cost is low Installation cost is high

cost of piping & valves is higher for all application due to additional shut off valve and expansion bellow in the suction line.

The same is not required.

6 Civil cost : (2 to 6 times more)

For all application horizontal pumps have to be located below the minimum water level of respective reservoir to facilitate flooded suction of pump and this requires excavation (Dry pit) of soil adjacent to respective reservoir sump.

Vertical pumps can be directly located inside the respective reservoir sumps and requires excavation (sum pit) for submergence of pump below minimum water level within the reservoir sump, which is nominal compared to excavation required for horizontal pump dry pit.

Cost of substruction like dry pit for horizontal pump is high

Cost of substruction like pump resting slab and sump pit is low.

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HORIZONTAL VERTICAL

Horizantal pumps will have to be

located indoor due to the requirement of a dry pit and so cost of super structure is an additional cost. For fire water pumps cost of super structure is higher in case of horizantal pumps due to higher floor space requirements.

Cost of super structure is low since vertical pump can be located in outdoor.

7 Other cost : Other cost like crane rails, electrical cables, lighting, ventilation etc. will be higher with horizantal type pump because of greater length of pump house.

8 maintenance cost is low Maintenance cost is very high

9 Efficiency is high Efficiency is low due to transmission loss.

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FORM T10 REV - A

MERITS/DEMERITS OF PLATE TYPE HEAT EXCHANGERS BLOW DOWN,

General :-

The plate type heat exchanger is an assembly of corrugated plates held between the stationary and follower plate with the help of long tie bolds.

Classifications of plate heat exchanger

a. Gasketted plate heat exchanger

b. Semi-welded plate heat exchanger

c. Double wall plate heat exchanger

d. Wide gap plate heat exchanger

e. Flow flex, the tubular plate heat exchanger

f. Graphite, plate heat exchanger

g. Plate evaporator

h Brazed plate heat exchanger

i. Fully - welded plate heat exchanger

Merits of plate heat exchanger

Low investment cost : High efficiency and their sheet Materials result in economical units, practically when expensive Materials are required.

Easy Maintenance : A PHE can generally be cleaned by operating the unit

with chemical detergents for a short period. Should a heat exchanger need to be opened for inspection or cleaning, the heating surface is 100% accessible simply by removing the tightening bolts.

Small space requirement : The PHE is extremely compact in design, relation to

its capacity and it does not require any extra space for service or Maintenance.

Great Thermal Efficiency /close : Plate pattern are designed to induce a high degree of

Temperature Approach turbulence which reduces fouling and improves heat transfer. This high turbulence in full counter current flow makes it economically feasible to use temperature approaches down to 1C

Flexibility : With in a couple of hours, the PHE can be

redesigned simply by adding, removing or rearranging plates within the length of the frame. Extended frame capacity can be supplied if the original capacity is expected to increase radically.

Lower Cooling Water

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FORM T10 REV - A

Flow Rate : Owing to identical channel geomentries as well as high thermal efficiency for both fluids, the PHE greatly reduces the cooling water flow rate. This in turn means lower installation costs for piping, valves and pumps.

Low hold up volume : The thin channels mean that the liquid volume is low

in comparison to other types of heat exchangers. This ensure quick process control and reduces total installation weight.

Low weight : The compact design and their plate materials

contribute to a low weight heat exchanger. A higher weight heat Exchanger in turn requires smaller foundations.

No vibrations : The Metal to Metal contact between plates means a

rigid plate free from vibrations. No welds : The absence of welds considerably reduces

expensive non-destructive test procedures. Demerits of Plate heat Exchangers Pressure drop : Pressure drop across the fluid is high when

compared to shell & tube type. Cost : Slightly higher when lower grade material are used

(such as carbon steel). Pressure : Not suitable for high pressure service Application : PHE is not used in condensing plant, vapourising,

super heating system. : Gaseous fluids not recommend to use in PHE

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FORM T10 REV - A

Gasket Material Selection with respect to Temperature & Application :-

Gasket Material Max. Temp. C Application

Nitrite rubber 135 Fatty Materials Butyl rubber 150 Aldehydes, Ketones &

esters. Ethylene propylene

rubber 150 High temp resistance

to a variety of chemicals

Viton 175 Minerals, vegetable & animal oils, fuels

Compressed asbestos 260 Organic solvents eg. chlorinated hydrocarbons.

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C:\Siva\REFERENCES\USEFUL BOOKS\DESIGN GUIDE-FICHTNER\WI-ME-DSN-126-001.doc FORM T10 REV - A

WATER COOLED SURFACE CONDENSER SIZING

Introduction Power plant condenser receives exhaust steam from the low pressure turbine and

condenses it to liquid for reuse. The surface condenser serves three important functions :

# Provides a low back pressure at the turbine exhaust to maximise plant

thermal efficiency and reduce the heat rate. # Conserves the high purity water for reuse in the boiler-turbine system to

DESIGN GUIDE-FICHTNER.pdf

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