Www.emt India.net Presentations2010 12 Power 13 14May2010 DahanuHeatRateImprovement13.05.2010

7/29/2019 Www.emt India.net Presentations2010 12 Power 13 14May2010 DahanuHeatRateImprovement13.05.2010

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Presented by

J. N. Dubey Sr Supdt ( EEMG)

NCPS -DADRI


2/92

HEATRATE IMPROVEMENT

THE PRESENTATION COVERSDEFINITION AND TYPES OF HEAT RATE

IMPORTANCE OF HEAT RATE IMPROVEMENT

CALCULATION OF HEAT RATE

CYCLE EFFICIENCY AND HEAT RATE

DIFFERENT TYPES OF HEAT LOSSES

PARAMETERS AFFECTING HEAT RATEPERFORMANCE OF EQUIPMENTSCONDENSER PERFORMANCE

HP/LP HEATERS PERFORMANCE

TURBINE PERFORMANCE

COOLING TOWER PERFORMANCE

BOILER PERFORMANCE

RAPH PERFORMANCE


3/92


HEAT REQUIRED IN KCAL FOR UNIT ( KWH)

GENERATION OF ELECTRICITY

UNIT OF HEAT RATE

KCAL / KWH

DESIGN UNIT HEAT RATE : 2274 KCAL/KWHACTUAL UNIT HEAT RATE : 2400 KCAL/KWH

DEVIATION : 126 KCAL/KWH


4/92


GROSS UNIT HEAT RATE

The ratio heat input to the boiler including allforms of chemical energy supplied and the

gross electrical generation.

For most functions (daily/monthly/annual

reporting, comparison/ benchmarking of units)

unit or plant heat rate is used.


5/92


NET UNIT HEAT RATE

A unit heat rate includes all heat input to theboiler. The heat input to the boiler include all

forms of chemical energy supplied and the net

electrical generation i.e., auxiliary power is to be

subtracted from gross electrical energy.


6/92


Gross Turbine Cycle Heat Rate (GTCHR)

A Gross Turbine Cycle heat rate includesonly heat input to the turbine cycle.

GTCHR is the ratio of total heat input to the

turbine cycle and the gross generator output.

Turbine Cycle : Starting from ESV to final

HP heater outlet

It includes HPT , IPT , LPT, condenser,

GSC , drain cooler LPH 1, 2, 3 ,

deaerator,HP heater 5 and HP heater 6


7/92


Boiler S.H HPT

R.H

IPT LPT

Condenser

CE

P

GSCDCLPH-1LPH-2

D/

A

HPH-6 HPH--5

BF

P

E

C

O

Ge

n

LPH-3

BLOCK DIAGRAM OF THERMAL POWER PLANT CYCLE


8/92


Description Unit value

COAL CV KCAL / Kg 39COAL COST ( Avg yearly) Rs / Ton 23

COAL COST Rs / Kg 2.

Cost of 1 K Cal Rs/ kcal 0.0005974

Generation Capacity of One Unit / day MU 5.

( 210x24/1000)

PLF %

Generation / day considering 95 % PLF MU 4.7

Generation / year considering 95 % PLF MU 1747.

Generation Capacity of One Unit / year kwh 17476200ost ev at on n eat ate y

1 kcal / kwh for yearly generation of

one unit

Lacs 10.

EFFECT OF DEVIATION OF HEAT RATE BY ONE KCAL/ KWH


9/92

IMPACT OF PARAMETERS ON HEAT RATE

S No. Parameter Unit Deviation H R Dev ( Kcal/kwh

1 HPT efficiency % + 1% - 4.5

2 IPT efficiency % + 1% - 4.5

3 LPT efficiency % + 1% -11.4

4 Condenser Back Pressure mm Hg +1mmHgC +2.0

5 M S Pr before ESV Kg/cm 2+1.0

Kg/cm2 -1.8

6 M.S.Temp Deg. C +1.0 Deg C -1.67 HRH Temp Deg. C +1.0 Deg C -0.68

8 RH Spray T/Hr +1 T/H +0.53

9 DM Make-Up % MCR + 1% + 20

10 Boiler efficiency % +1% -26

HP Heater -TTD Deg. C +1.0 Deg C +1.8

HP Heater - DCA Deg. C +1.0 Deg C +0.25

11 Excess Oxygen % + 1% +6.6

12 Flue Gas Temp. Deg. C +1.0 Deg C +1.3

COMPUTATION OF HEAT RATE


10/92


DIRECT METHOD ( COAL BASED)

RATIO OF HEAT INPUT TO GROSS GENERATION

COAL CONSUMPTION X COAL GCV

HEAT RATE = ----------------------------------------------------------

GROSS GENERATION

EASY CALCULATION

FEW PARAMETERS

ANALYSIS OF DEVIATION OF HEAT RATE NOT POSSIBLE

UNCERTAINTY IS VERY HIGH



11/92


LOSS METHOD ( PARAMETERS BASED)

RATIO OF TURBINE CYCLE HEAT RATE TO BOILER EFFICIENCY

TURBINE CYCLE HEAT RATE *100

HEAT RATE = ----------------------------------------------------------

BOILER EFFICIENCY

DETAILED ANALYSIS OF DEVIATION OF HEAT RATE POSSIBLE

MEASUREMENT OF MANY PARAMETERS IS REQUIRED

LONG CALCULATION



12/92


GROSS TURBINE CYCLE HEAT RATE

TURBINE CYCLE HEAT RATE (KCAL/KWH) =

Qms(Hms- Hfwo) + Qhrh(Hhrh-Hcrh)+Qrh(Hhrh- Hrhs)

-----------------------------------------------------------------------GROSS LOAD



13/92


HEAT RATE & EFFICIENCY

OUT PUT

EFFICIENCY = ------------------

IN PUT

860 X 100

EFFICIENCY (%) = -------------------

HEAT RATE



14/92


EXAMPLE OF HEAT RATE & EFFICIENCY

DESIGN GROSS TURBINE CYCLE HR = 1985 KCAL / KWH

860 X 100

DESIGN EFFICIENCY OF TURBINE CYCLE =------------ = 43.3 %

1985

ACTUAL GROSS TURBINE CYCLE HR = 2050 KCAL / KWH

860 X 100

ACTUAL EFFICIENCY OF TURBINE CYCLE =------------ = 41.95 %

2050



15/92


EXAMPLE OF HEAT RATE & EFFICIENCY

DESIGN UNIT HEAT RATE = 2274 KCAL / KWH

860 X 100

DESIGN EFFICIENCY OF UNIT =------------ = 37.8 %

2274

ACTUAL UNIT HEAT RATE = 2400 KCAL / KWH

860 X 100

ACTUAL EFFICIENCY OF UNIT = ------------ = 35.8 %

2400

MAXIMUM LOSS IN CONDENSER APPROXIMATE 58 %


16/92

HEAT LOSS

HEAT LOSS DUE

TO OPERATING

PARAMETERS

HEAT LOSS DUE

TO EQUIPMENT

PERFORMANCE

CONTROLABLE

HEAT LOSS

UN-CONTROLABLE

HEAT LOSS

ACCOUNTABLE UN ACCOUNTABLE

DRAIN VALVE PASSING

/RADIATION LOSS

HEAT LOSS DUE TO OPERATING PARAMETER


17/92

HEAT LOSS DUE TO OPERATING PARAMETER

1. LOAD (PARTIAL LOADING) ACCOUNTABLE /CONTROLABLE

2. MS PR. BEFORE ESV ACCOUNTABLE / CONTROLABLE

3. MS TEMP. BEFORE ESV ACCOUNTABLE / CONTROLABLE4. HRH TEMP. BEFORE IV ACCOUNTABLE / CONTROLABLE

5. RE HEATER SPRAY ACCOUNTABLE / CONTROLABLE

6. COND VACUUM ACCOUNTABLE / CONTROLABLE

7. CW INLET TEMP ACCOUNTABLE /UN-CONTROLABLE

8. CW FLOW ACCOUNTABLE / CONTROLABLE

9. DM MAKEUP ACCOUNTABLE / CONTROLABLE

10. FW TEMP. AT HPH 6 O/L ACCOUNTABLE / CONTROLABLE

11. APH EXIT FLUE GAS TEMP ACCOUNTABLE / CONTROLABLE

12. EXCESS O2 ACCOUNTABLE / CONTROLABLE

HEAT RATE IMPROVEMENT PLAN


18/92

HEAT RATE IMPROVEMENT PLAN

REAL TIME HEAT RATE

DEVIATIONDAILY HEAT RATE

DEVIATION

REMEDIAL ACTION

MONITORING

PERFORMANCE TESTING

BOILER EFFICIENCY TEST

TURBINE CYCLE HEAT RATE

CONDENSER PERFORMANCE

HEATER PERFORMANCE

TURBINE EFFICIENCY

HELIUM LEAK DETECTION TESTPRESSURE SURVEY

OXYGEN SURVEY

RAPH PERFORMANCE

MILL CLEAN AIR FLOW TEST

MILL DIRTY AIR FLOW TEST

HOT PA TRAVERSE TEST

HIGH VELOCITY THERMOCOUPLE TEST

COOLING TOWER PERFORMANCE TEST

ANALYSIS OF TEST RESULT AND

REMEDIAL ACTION

TRENDING

TRENDING

OF

KEY PARAMETE

AND

EFFICIENCY TERESULTS

FOR MONITORI

OF

RATE OF

DETORIATIO

DADRI THERMAL PLANT ON LINE HEAT RATE DEVIATION


19/92

DADRI THERMAL PLANT-ON LINE HEAT RATE DEVIATION


20/92

DAILY HEAT RATE DEVIATION REPORT


21/92

DATE: 28-May-07

S No. Unit

(A) Accountable Heat Rate Dev Kcal/kWh Design

1 Load ( Partial loading) MW 210.0 211.9-2.5 214.6 -6.0 216.3 -8.18 214.6 -6.0

2 M S Pr before ESV Kg/cm 2 150.0 150.9 -1.57 150.6 -1.01 150.6 -1.02 150.8 -1.38

3 M.S.Temp before ESV Deg. C 537.0 538.1 -1.78 539.4 -3.77 538.1 -1.79 538.3 -2.09

4 HRH Temp before IV Deg. C 537.0 538.6 -1.11 537.2 -0.10 536.6 0.31 535.4 1.14

5 Reheater Attemperation T/Hr 0.0 5.83.19 4.3 2.24 8.70 4.48 7.0 3.73

6 mm Hg

76.0 60.1 -2.04 55.1 -11.72 60.8 -2.25 67.9 13.56

7 C W Inlet Temp. Deg. C 32.0 27.8-29.76 27.8 -30.08 28.1 -28.15 27.8 -29.76

8 DM Make-Up % MCR 0.0 0.0003.61 0.00 13.15 0.00 3.24 0.00 5.73

9 FW Temp at HPH O/L Deg. C 247.0 243.2 3.1 242.0 4.5 244.1 3.3 242.3 4.3

10 Dry Flue gas loss (DFG) % 4.77 4.89 3.06 5.1 9.04 5.81 28.09 5.73 25.39

Effect of coal quality on DFG % 0.0 0.0 0.0 0.0

(a) Oxygen at eco outlet % 3.54 2.62 2.35 2.57 2.86

(b) APH exit flue gasTemp.(Corr) Deg. C 136.0 127.3 135.8 144.9 142.9

(c) APH -A Leakage %10.0 19.4 18.8 18.6 18.2

APH -B Leakage %10.0 16.8 14.5 19.3 16.3

11 Wet Flue Gas Loss % 5.83 5.75-2.03 5.78 -1.21 5.82 -0.24 5.82 -0.31

(a) Moisture in coal % 12.0 10.18 10.18 10.18 10.18

(b) % of Hydrogen in Coal %2.26 2.76 2.76 2.76 2.76

12 Unburnt Carbon loss %1.2

Ref.0.80.72 -2.24 0.76 -1.01 0.79 -0.16 0.69 -2.82

13 Startup oil Consumption KL 0.0 0.00 0.0 0.00 0.0 0.0 0.0 0.00

14 HPT efficiency % 85.45 83.1010.87 84.23 5.59 83.03 11.27 84.22 5.65

15 IPT efficiency % 90.38 88.18 9.99 88.01 10.67 88.00 10.90 88.32 9.28

Total (A) Kcal/kWh -9.13 -9.7 19.8 26.4

(B) Unaccountable H R Deviation Kcal/kWh 30.1 22.2 29.1 12.9

Total Heat Rate Deviation ( A+ Kcal/kWh 21.0 12.5 48.8 39.3

(C) Design Heat Rate at Full Load Kcal/kWh 2274.0 2274.0 2274.0 2274.

(D) Derived Unit Heat Rate (A+BKcal/kWh 2295.0 2286.5 2322.8 2313.

Condenser Back Pr (loss due

to CW flow , load ,dirty tube

and air ingress)

Heat

Rate

Dev.

Param

eter

Value

Heat

Rate

Dev.

Parame

ter

Value

ParameterParam

eter

Value

Heat

Rate

Dev.

Param

eter

Value

DAILY HEAT RATE DEVIATION REPORT

UNIT-1 UNIT-2 UNIT-3 UNIT-4

Heat

Rate

Dev.

Accountable Heat Rate Deviation


22/92

Accountable Heat Rate Deviation

S No. Unit DESIGN1 Load ( Partial loading) MW 210.0 211.9 -2.52 M S Pr before ESV Kg/cm 2 150.0 150.9 -1.573 M.S.Temp before ESV Deg. C 537.0 538.1 -1.78

emp e ore eg. 537.0 538.6 -1.115 Reheater Attemperation T/Hr 0.0 5.8 3.19

6 mm Hg76.0 60.1 -2.04

7 C W Inlet Temp. Deg. C 32.0 27.8 -29.768 DM Make-Up % MCR 0.0 0.000 3.619 FW Temp at HPH O/L Deg. C 247.0 243.2 3.1

10 Dry Flue gas loss (DFG) % 4.77 4.89 3.06

11 Wet Flue Gas Loss % 5.83 5.75 -2.0312 Unburnt Carbon loss % 1.2 0.72 -2.24

13 Startup oil Consumption KL 0.0 0.00e c ency 85.45 83.10 10.87

15 IPT efficiency % 90.38 88.18 9.99

Total (A) Kcal/kWh -9.13

CW flow , load ,dirty tube and air

ingress)

ParameterParameter

Value

Heat Ra

Dev.

Calculation of Unaccountable Heat Rate


23/92

Calculation of Unaccountable Heat Rate

1: Calculation of Unit Heat Rate by monthly Turbine

Cycle Heat Rate Test and Boiler Efficiency Test

Turbine Cycle Heat Rate

2: Unit Heat Rate =--------------------------------- x100

Boiler Efficiency

3: Total HR Deviation = Test Unit HR- Design Unit HR

4: Total HR Deviation = Accountable HR+ Unaccountable H

5: Unaccountable HR= Total HR Deviation -- Accountable H

Accountable HR is calculated taking parameters at the time o

HEAT LOSS DUE TO EQUIPMENT


24/92

HEAT LOSS DUE TO EQUIPMENT

PERFORMANCE

;


25/92

FACTOR AFFECTING CONDENSER BACK PR

1 ) C W inlet temperature

2 ) C W Flow

3 ) Condenser Heat Load4 ) Air ingress

5 ) Scale inside Tube

6 ) Condenser Tube Choking


26/92

EFFECT OF CW TEMP ON BACK PRESSURE

32 35.639.9 43.7

48.453.5

59.365.6 72.4

79.88

0

20

40

60

80

100

15 17 19 21 23 25 27 29 31 33 3CW INLET TEMP ( DEG C)

COND.BACK

PRESS

URE(MMH

GC)


27/92

EFFECT OF CW FLOW ON BACK PRESSURE

7375.04

76.9879.09

81.45

84.09

87.15

90.64

70

75

80

85

90

95

100

17000 18000 19000 20000 21000 22000 23000 2400CW FLOW M3/HR

COND

.BACK

PRESSURE

(MMHGC)


28/92

EFFECT OF CONDENSER HEAT LOAD

79.8

78.2

76

73.8

73

74

75

76

77

78

79

80

81

23 23.5 24 24.5 25 25.5 26 2

CONDENSER HEAT LOAD ( K CAL/HR)

CONDEN

SERBACK

PR(M

MHGC)



29/92


EVALUATION OF CONDENSER PERFORMANCE

1: Deviation in condenser back pressure

2: TTD = Terminal Temperature Difference

= Tsat- CW outlet Temp

whereTsat = Saturation Temp corresponding to back pressure

3: Under cooling = Tsat- Condensate temp in Hot well4: Air Depression = Tsat T air steam mixure5: DISSOLVED O2 IN CONDENSATE IN HOT WELL

6 : DIFFERENTIAL PRESSURE OF CW IN/OUTLET



30/92


Deviation in condenser back pressure

Dev. of test condenser back pressureFrom expected back pressure

Dev. of corr condenser back pressFrom Design back pressure

Primary Method LMTD MethodLMTD Method

CALCULATION OF EXPECTED SATURATION TEMP AND


31/92

CALCULATION OF EXPECTED SATURATION TEMP ANDEXPECTED BACK PRESSURE AT VARIATION OFDIFFERENT OPERATING PARAMETERS

The following equations are used

Expected Tsat = CW inlet temp + CW temp rise + TTD( General Equation)

Expected back pressure = Pressure corresponding toExpected saturation temp


32/92

1) Expected Tsat (d) = CW inlet temp (d) + CW temp

rise (d) + TTD (d)

32 (deg C)+ 10.8 (deg C)+ 3.2 (deg C) = 46 ( deg

Expected back pressure (d) = Pressure

corresponding to Expected saturation temp (d)76 mm HgC = Pd

Eff t f CW i l t l


33/92

2) Effect of CW inlet aloneExpected Tsat = CW inlet temp (a) + CW temp rise (d

+ TTD (d)

Expected back pressure = Pressure correspondingto Expected saturation temp = PcwiVariation due to CW inlet temp = Pd Pcwi

Example:C W inlet temperature ( Avg) = 17.7 Deg CDesign C W inlet temperature = 32.0 Deg C

Expected Tsat = 17.7+10.8+3.2 = 31.7 Deg C

Expected back pressure = 35.12 mmHgcGain due to CW inlet temp = 76-35.12 = 40.88 mm

Hgc

3) Eff f CW i l CW fl d l d


34/92

3) Effect of CW inlet , CW flow and loadExpected Tsat = CW inlet temp (a) + CW temp rise (a

+ TTD (d)= CW outlet temp (a) + TTD (d)Expected back pressure = Pressure correspondingto Expected saturation temp = Pcwif

Variation due to CW flow and load = Pcwif PcwiExample: CW Inlet temp = 17.7 , CW outlet temp =32Expected Tsat = 32+3.28 = 35.28 Deg CExpected back pressure = 42.83

Deviation due to CW flow and Load= 42.83-35.12=7.71 mm HGC

Back pr variation due to air and dirty tube ( Bad


35/92

performance of condenser

Actual condenser back pr = 40.90 mm HgCExpected Back pressure = 42.83 mm HgC

= Condenser Back Pressure (a)- Pcwif

=40.90-42.83 = -1.93


36/92

CALCULATION OF EXPECTED BACK

PRESSURE BY LOG MEAN TEMP

DIFFERENCE ( LMTD ) METHOD



37/92


CALCULATION OF EXPECTED SATURATION TEMP ANDEXPECTED BACK PRESSURE BY CHANGE IN LMTD METHOD.

DETERMINATION OF CONDENSER DUTY

Condenser Duty = (Heat Added MS + Heat Added CRH +Heat added by BFP + Heat added by RH

Attemperation) - 860 (Pgen + Pgen

losses + Heat Loss rad.)



38/92


DETERMINATION OF CONDENSER FLOW:

Cond DutyCW Flow = ------------------------ m3/hr

Cp (Tout Tin) x DWhere:

C.W Flow = m3/hrCond Duty = kcal/hrCp = 1 kcal/kg o C (Specific heat of water)D = 1000 kg/cubic meter (Density of water)Tout = OC (Average C.W Outlet temp.)Tin = OC (Average C.W Inlet temp.)



39/92


Water Velocity in Condenser Tube

C.W Flow Rate x 106Tube Velocity = ---------------------------------------------------

--3600 x Tube Area x (Number Tubes

NumberPlugged)

Where:Tube Velocity = m/sec

C.W Flow Rate = m3/hrTube Area = mm2



40/92


Computation of Log Mean Temperature Difference (LMTDTout - Tin

LMTD = -------------------Tsat Tin

Ln ----------Tsat Tout

Where:LMTD = 0C

Tsat = 0 C (saturation temp corresponding to backpressure)



41/92

DETERMINATION OF EXPECTED LMTD FOR DEVIATION FROM DESIGN VALUE

* Correction for C.W. inlet temperature (ft)

Saturation Temp Test - LMTD testFt = -------------------------------------------Saturation Temp Design - LMTD design



42/92

Correction for C.W. flow (fw)

1/2Tube velocity test

fw = -----------------------Tube velocity design

*Correction for condenser heat load (fq)Cond. duty design

fq = ------------------------Cond. duty test



43/92

Expected LMTDLMTD expected = LMTD test x ft x fw x fq oC

Determination of Expected Saturation Temperature:(taking into consideration deviation in operating value fromdesign values)

[Tin Tout x eZ]Sat. Temp. Expected: = --------------------------- oC

[1 - eZ

]Where:Tin = Design C.W. inlet temp.Tout = Design C.W. outlet temp.

Tout Tin

Z = ----------------------Expected LMTD

Expected Back Pressure = Derived from steam tablecorresponding to expected saturation temperature.

ACTION FOR IMPROVINGCONDENSER PERFORMANCE


44/92


1: REGULAR MONITORING OF CONDENSER PERFO

2: IDENTIFICATION AND ATTENDING OF HIGH

ENERGY DRAIN VALVE PASSING

3:IDENTIFICATION OF AIR INGRESS POINTS BY

HELIUM LEAK DETECTION TEST ( WHEN UNIT IS RUNNI

4: IDENTIFICATION OF AIRINGRESS POINT BYSTEAM PRESSURISATION TEST(DURING UNIT OVERHAUL

5:MAINTAINING PROPER SEAL STEAM PRESSURE

AND TEMP

7: PROPER SEALING OF ALL THE VALVE GLANDSIN LINES UNDER VACUUM

ACTION FOR IMPROVINGCONDENSER PERFORMANCE


45/92


8: PROPER SEALING OF GLANDS OF STANDBY C E

9:MONITORING SEAL WATER PARAMETERS OF

VACUUM PUMP

10: MONITORING OF AIR DEPRESSION

11: JET/CONCO CLEANING OF WATER TUBES

12: PROPER VENTING OF WATER BOX DURINGCHARGING OF CONDENSER

13:ENSURE PROPER OPERATION OF HP FLASH BO

SPRAY SYSTEM



46/92

IDENTIFICATION OF AIR INGRESS



47/92

AIR INGRESS IDENTIFICATION

HELIUM

LEAK DETECTION TEST

CONDENSER FLOOD TEST

STEAM PRESSURISATION TEST



48/92

WORKING PRINCIPLE:

The Helium Leak Detection Test is new method based on heliumacting as tracer gas that allows an easy and quick location of leaksThe use of helium is advantageous because it is a nontoxic,nonflammable, relatively inexpensive and quickly diffuses throughsmall leaks.

Helium is sprayed at the point where leak is to be checked bymeans of portable unit which has facility of helium spray. If there iany ingress inside condenser, Helium will also enter with air which

is displayed in Heli Test Gen.



49/92

Heliu

mCylinder

Spray gun

Set up for Helium Spray

PREPARATION FOR TEST:-(A)Set up for Helium Spray:1: Install a gas regulator on Helium gas cylinder.

2: Connect a spray gum through PVC tube. The Portable Leak Detector ( PLI ) may be also usefor spraying helium .

3: Adjust helium gas pressure 1.5 to 2.0 Kg / cm 2.



50/92

Vacuum Pump

Exhaust

Vacuumpump

Helium leak

Detector

Moisture

separator

Vacuum

Pump

Connecting pipe

Water drop

separator

Silica gel

Set for Helium leak Detection



51/92



52/92



53/92



54/92

CONDENSER FLOOD TEST

&STEAM PRESSURISATIONTEST Condenser flood test is done by feeling DM water incondenser shell side and water leakage is checked ( if any)Standard procedure should be folllowed for Condenser flood

testSteam pressurisation test is done by pressurisation ofcondenser by steam leakage is checked ( if any)Standard procedure should flow for Condenser steampressurisation test


55/92

LP/HP HEATERS PERFORMANCE


56/92

LP / HP HEATER PERFORMANCE IS MONITORED BY

MONITORING FOLLOWING PERFORMANCES INDICES

TERMINAL TEMP DIFFERENCE ( TTD)

TTD= Ts-FW outlet temp

DRAIN COOLER APPROACH ( DCA)

DCA = DRIP TEMP- FW inlet temp

TEMP RISE = (FW outlet temp- FW inlet temp )



57/92

TTD HIGH:

FOULING IN SIDE TUBE

SCALE OUTSIDE OF TUBE

AIR BLANKETING

MIXING OF WATER THROUGH PARTING PLANE OF

WATER BOX ( SHORT CIRCUITING) ONE OR MORE PREVIOUS HEATER/S OUT OF SERVICE

HIGH LEVEL OF HEATER ie POOR CASCADING SYSTE

HIGH DCA



58/92

HIGH DCAHEATER LEVEL TOO LOW ie POOR CASCADING SYSTEM

LOW TEMP RISE LOW EXTN STEAM PRESSURE

From turbine extration

Isolating valve not fully open

FOULING IN SIDE TUBE

SCALE OUTSIDE OF TUBE

AIR BLANKETING

MIXING OF WATER THROUGH PARTING PLANE OFWATER BOX ( SHORT CIRCUITING)

ONE OR MORE PREVIOUS HEATER/S OUT OF SERVICE

HIGH LEVEL OF HEATER ie POOR CASCADING SYSTE


59/92

TURBINE EFFICIENCY


60/92

Used Energy


61/92

Used EnergyTurbine Efficiency =

Available Energy

hin - hout=

hin hisen

Wherehin = Enthalpy at Cylinder Inlet conditionshout = Enthalpy at Cylinder Outlet conditionshisen = Isentropic Enthalpy


62/92


63/92

COOLING TOWERPERFORMANCE


64/92

Wet Bulb Temperature (WBT) at Tower inlet

WBT/ DBT for RH

Cold Water Temperature

Hot Water Temperature

CW Flow to each Tower


65/92

Approach

Difference between the Cold Water Temperatureat CT outlet and Inlet air Wet Bulb Temperature

RangeDifference between the Hot Water Temperature(inlet to CT) and Cold Water Temperature(outlet of CT)Effectiveness

Ratio of Range to Range+Approach


66/92


67/92

Tower Capability

The most reliable means to assess thecooling tower thermal performance.

It is defined as the percentage of water thatthe tower can cool to the design cold watertemperature when the inlet wet-bulb,cooling range, water flow rate at theirdesign value.

Tower Capability


68/92

Tower Capability in Percentage = Test Flow RatePredicted Water

Test flow rate :Measured by 3 port hydraulic pitot

Predicted Water Flow Rate

Calculated from Manufacturer graphs and actual

test condition

T C bilit


69/92

Tower Capability

Tower Capability in Percentage = Adjusted Test Flow RatePredicted Water Flow Rate

Adjusted Test = Measured flow x { Design KW of fans}0.333

Flow Rate { Test KW of Fans }

Predicted Water Flow Rate = Calculated from Manufacturergraphs and actual test

conditionsi.e. WBT, Range and Cold water

temperature.


70/92


71/92


72/92


73/92

Dry flue gas loss

BOILER PERFORMANCE


74/92

Dry flue gas loss

Loss due to fuel moisture

Loss due to fuel hydrogen

Loss due to air moisture

Loss due to unburnt carbon

Radiation loss

Other losses like sensible heat loss

ONLY TWO LOSSES ie DFG LOSS AND

UNBURNT CARBON LOSS ARECONTROLLABLE

BOILER PERFORMANCE

S N Heat Losses (%) design Correcte


75/92

S.N Heat Losses (%) design CorrecteTest Va

1 Dry Gas Loss % 4.77 5.303

Wet flue gas loss % 5.83 5.83

2

Loss due to UnburntCarbon

%

1.2 0.97

4Loss due to moisture in

air%

0.12 0.12

5

Radiation & unaccountedLoss

%

0.78 0.78

Total loss 12.7 13.0BOILER EFFICIENCY % 87.3 87.00

OPTIMISATION OF BOILER EFFICIENCY


76/92

HCV ALL LOSSES EFFICIENCY

GAS OUT TEMPLOSSES (DRY GAS, HYDROGEN

FUEL MOISTURE AIR

MOISTURE, SENSIBLE HEAT

RATE LOSS OF ASH)

EFFICIENCY

EXCESS AIR

LOSSES (DRY GAS, AIR

MOISTURE )

UNBURNTS LOSS

EFFICIENCY

FUEL MOISTURE LOSSEFFICIENCY

AIR MOISTURELOSS EFFICIENCY

OPTIMISATION OF BOILER EFFICIENCY


77/92

H2 IN FUEL H2 LOSS EFFICIENCY

UNBURNTSUNBURNTS EFFICIENCY

MILL REJECT RATE LOSS EFFICIENCY

FUEL MOISTURE LOSSEFFICIENCY

MILL REJECT CVLOSS EFFICIENCY

DRY FLUE GAS LOSS HIGH

BOILER PERFORMANCE


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DRY FLUE GAS LOSS HIGH

INEFFECTIVE SOOT BLOWING

HIGH DRAFT

POOR RAPH PERFORMANCE

SEAL LEAKAGE IN APH

HIGH EXCESS AIR

HIGH TEMPERING AIR

AIR INGRESSHIGH APH DP

UNBURNT CARBON LOSS:

BOILER PERFORMANCE


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POOR COAL FINNESS

IMPROPER COMBUSTION

Performance Indicators


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Air-in-Leakage

Gas Side Efficiency

X - ratio

Gas & Air side pressure drops

AH Performance Monitoring

O2 & CO2 in FG at AH Inlet


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2 2

O2 & CO2 in FG at AH Outlet

Temperature of gas entering / leaving air heater

Temperature of air entering / leaving air heater

Diff. Pressure across AH on air & gas side

Air Heater Leakage - Calculation


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Empirical relationship using the change in

concentration of O2 in the flue gas

= O2out - O2in * 0.9 * 100

(21- O2out

)

Gas Side Efficiency


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Ratio of Gas Temperature drop across the air

heater, corrected for no leakage, to the temperaturehead.

= (Temp drop / Temperature head) * 100

where Temp drop = Tgas in -Tgas out (no

leakage)

Temp head = Tgasin - T air in

Gas Side Efficiency = (333.5-150.5) / (333.5-36.1) = 61.5 %


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Tgas out (no leakage) = The temperature at which

the gas would have left the air heater if there were nAH leakage

= AL * Cpa * (Tgas out - Tair in) + Tgas out

Cpg * 100

X Ratio

Ratio of heat capacity of air passing through the air


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heater to the heat capacity of flue gas passing

through the air heater.

= Wair out * Cpa

Wgas in * Cpg

= Tgas in - Tgas out (no leakage)

Tair out - Tair in

Design 0.69 %

X-Ratio depends onAir infiltration, air & gas mass flow rates


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, gX-ratio does not provide a measure of thermal

performance of the air heater, but is a measure of theoperating conditions.

A low X-ratio indicates either excessive gas weight

through the air heateror that air flow is bypassing the airheater.

A lower than design X-ratio leads to a higher thandesign gas outlet temperature & can be used as an

indication of excessive tempering air to the mills or

excessive boiler setting infiltration.

Air Ingress Calculations

Ai i tifi ti i d ith th


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Air ingress quantification is done with the same

formulae as those used for calculation of AHleakage

Air ingress = O2out - O2in * 0.9 * 100

(21- O2out)

The basis of O2 or CO2 calculation should be the

same either wet or dry.

PASSING OF VALVES

VALVE PASSING


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INCREASES CONDENSER HEAT LOAD

INCREASES HEAT RATE

HP/LP BY PASS VALVE PASSINGEFFECTS ON HEAT RATE

CONCLUDING REMARKS:CONCLUDING REMARKS


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FOR IMPROVING HEAT RATE

Maintain critical parameter as per rated value

Maintain optimum HP heater level.

There is possibility of air ingress in LP heater1 and LP heater -2 as both heaters are running

in vacuum even at full load. Air evacuation

valve connected to condenser may be kept crac

open

Identify air ingress in vacuum system and getCONCLUDING REMARKS


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attended

Ensure proper sealing of valves which are in

vacuum

Reduce High energy drain passing

Monitor for critical valve (like HP/LP by pass

valve) passing

Avoid R H spray

Minimize system water / steam leakage

Optimize deaerator vent openingCONCLUDING REMARKS


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Optimize excess oxygen

Optimize tempering air

Monitor vacuum pump seal water temp


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