comparing the thermal power plant performance at various output loads by energy auditing (a...

7/30/2019 Comparing the Thermal Power Plant Performance at Various Output Loads by Energy Auditing (a Statistical Analyzi

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International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 6340(Print), ISSN 0976 6359(Online) Volume 2, Issue 2, August- December (2011), IAEME

111

COMPARING THE THERMAL POWER PLANTPERFORMANCE AT VARIOUS OUTPUT LOADS BY ENERGY

AUDITING (A STATISTICAL ANALYZING TOOL)

1Sahil Sardana, 2Rajender Kumar, 3Manjinder Bajwa, 4Piyush Gulati1Student, M.Tech., YMCA Univ. of Technology, Faridabad-121004 (India)

2

Asst. Prof., Department of Mechanical Engineering,Manav Ravchna International University, Faridabad-121003 (India)3,4Asst. Prof., Department of Mechanical Engineering,

Lovely Professional University, Jalandhar, Punjab-144402 (India)# Corresponding Contact: [email protected] , [email protected]

ABSTRACT

In the present scenario of rapidly growing demand of energy in transportation,agriculture, domestic and industrial sectors, the auditing of energy has becomeessential for over coming the mounting problems of the world wide crisis andenvironmental degradation. There are two factors contributing to the increase in theenergy consumption, one is more than 20% increase in worlds population andanother one is worldwide improvement in standard of living of human being. Theindustrial sector consumes about 50% of total generated energy. Therefore improvingenergy efficiency is the main focus of Energy Auditing. Experiments are carried outto validate the results, obtained by the Energy Auditing at Panipat Thermal PowerStation in Unit 7 th which has maximum power generated capacity of about 250MW.The auditing of energy is basically determining the efficiency of Unit 7 th of PTPS.Energy Auditing in thermal power plant covers the overall process of data collectionand carrying out technical and financial analysis to evolving specific energymanagement action. Energy Audit identifies the performance of each & everyequipment and compares it with the base case.

KEYWORDS : Energy Management, Energy Audit, Power Plant, and EnergyConservation.

1.0 INTRODUCTION

To meet the growing demand for energy in industries, one of the aims is to identifythe technical support in improving their energy performance through comprehensiveenergy audits, implementation assistance, technology audits, and capacity building.

INTERNATIONAL JOURNAL OF MECHANICALENGINEERING AND TECHNOLOGY (IJMET )

ISSN 0976 6340 (Print)ISSN 0976 6359 (Online )Volume 2, Issue 2, August- December (2011), pp. 111-125 IAEME: www.iaeme.com/ijmet.htmlJournal Impact Factor (2011) - 1.2083 (Calculated by GISI)www.jifactor.com

IJMET I A E M E


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Energy audits help in identifying energy conservation opportunities in all the energyconsuming sectors. While these do not provide the final answer to the problem, but dohelp to identify the existing potential for energy conservation, and induces theorganizations/individuals to concentrate their efforts in this area in a focused manner.

1.1 Energy Audit: An energy audit is a technique for identifying energy losses,quantifying them, estimating conservation potential, evolving technological optionsfor conservation and evaluating techno economics for the measures suggested.

i) Assist industries in reducing their energy consumption.ii) To promote energy-efficient technologies among industry sectors.iii) Disseminate information on energy efficiency through training programs and

workshops.iv) To promote transfer of energy-efficient and environmental-sound

technologies to the industrial sectors in the context of climate change.

1.2 Energy Audit Technique: The energy audit evaluates the efficiency of allprocess equipment/systems that use energy. The energy auditor starts at the utility

meters, locating all energy sources coming into a facility. The auditor then identifiesenergy streams for each fuel, quantifies those energy streams into discrete functions,evaluates the efficiency of each of those functions, and identifies energy and costsavings opportunities. The types of Energy Audit are as follows:

A. Walk through AuditB. Total System AuditC. Fired HeatersD. Boilers/Steam Generations PlantE. Steam System AuditF. Electrical System Audit

G. Insulation Audit

H. Specific EnergyConsumption

I. Hot Steam AnalysisJ. Cooling Systems AuditK. Energy Projects

Evaluation

From the above mentioned systems, this research work containing the study of Total

System Audit and its implementation methodology.

1.2 Total System Audit: This approach analysis the total system by detailed analysisas the total energy data is entered in a master database file. This contains design dataand also the observed data. This approach gives the energy performance of the totalsystem and identifies areas of improvements on energy cost or energy quantity basis.This method requires rigorous data entry and analysis.2.0 LITERATURE REVIEWOrganizational structure of electricity supply industry in India has been evolutionaryin nature. To understand this evolution it would be necessary to go over the pasthistory of the electricity supply industry. In the year 1883 the first electric supplyundertaking in the country was sponsored by a company, which constructed a small-generated solution in the city of Surat (Gujrat).

Energy conservation of the systems has become the topic of research in the recentperiod. Many researchers investigated and formulated the effects of energyconservation for the efficient energy usage particularly in industrial sector.

E.Raask [1969] , elaborated about tube failures occurring in the primary super heatersand repeaters and in economizers of coal fired boilers, which are result of erosion,wear caused by impaction of ash particles.


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Pilat et. Al. [1969] , discussed about source test cascade impact or for measuring thesize distribution of particles in stacks and ducts and air pollutant emission sources.This impactor is inserted inside the duct or stack to minimize tubing ball losses andwater condensation problem.

Schulz [1974] , studied the size distribution of sub-micron particles emitted from apulverized coal fired power plant and were measure using two types of cascadeimpactors. Scanning electronic microscope photographs shows particles werespherical with mean size entering and leaving the electrostatic precipitator of 5 and 2-1/4 micrometers although the slope of curve for each impactor differed.

Neal [1980] , abbreviated about the conventional automatic control of boiler outletsteam pressure by means of the demand to the pulverized fuel mills has been found tobe unstable on some coal fired-boiler turbine units. The frequency response of millsand boiler are obtained from tests in which the mill demand was perturbed with singlefrequency sinusoids. It is impracticable to measure the fuel output from the millsdirectly, but this is inferred from oxygen in the flue gas measurement coal/ashproperties.

Doglin [2001], abbreviated after reviewing the current combustion technologies forthe burning pulverized coal with frequent and large fluctuation in coal quality and

load demand, a new concept of quasi constant temperature combustion forpulverized coal is purposed.

There are more than fifty researchers whose research in the same field. The main aimof their research is to conserved the energy for future and reduce the energy lossduring transformations from one form to other.

3.0 INTRODUCTION TO THERMAL POWER PLANT

Thermal Power Station Panipat, a bunching of eight individual units with totalinstalled capacity of 1360 MW is located about 8 KM in the west of Panipat city on

Panipat-Hissar National Highway and is surrounded by cultivated green fields. Inaddition, 640 acres of saline wasteland is earmarked for disposal of ash. The plant isequipped with a huge residential colony to ensure availability of staff and officersround the clock. Unit No. 1 was commissioned on 1 st November, 1979 Haryana dayby the then President of India Shri Neelam Sanjeeva Reddy with subsequentcommissioning of Units. Table 1 shows the overall means the total performance of 8Units year by year.

Table 1. Performance of Panipat Thermal Power Station

Year Generation(MW)Plant LoadFactor (%)

AuxiliaryCons. (%)

OilConsumption(ml/kwh)

CoalConsumption(kg/kwh)

2000-01 2868.835 50.38 11.80 13.72 0.828

2001-02 2656.030 46.65 11.75 14.22 0.8242002-03 2856.040 50.02 11.41 6.89 0.7842003-04 2727.994 47.91 11.43 6.23 0.7912004-05 4123.94 61.86 10.67 3.04 0.7692005-06 4992.264 66.26 10.14 3.49 0.7452006-07 5949.260 78.75 10.08 3.21 0.7442007-08 5756.5968 71.14 10.74 3.90 0.7622008-09 8135.6993 68.53 9.79 3.56 0.7142009-10 9908.1265 83.17 9.48 1.39 0.699


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3.1 Basic Information regarding Power Generation at Thermal Power PlantStation

Thermal Power Plant burns fuels and uses the resultant heat to convert water in thesteam, which drive the turbo generator. The fuel may be fossil (Coal, Oil or NaturalGas) or it may be fissionable (uranium). Whichever fuel is used the object is same to

convert heat into mechanical energy into electricity by rotating a magnet inside a setof windings.Conventional power plants work on RANKINE CYCLE. The cycle may be split intodistinct operations:

Water is admitted to the boiler raised to boiling temperature and thensuperheated.

The superheated steam is fed to a steam turbine where it does work on theblades as it expends.

The expended steam is rejected o the condenser and the resultant condensate isfed back to the boiler via feed heaters.

The turbine drives a generator, which is turn supplies electricity to the busbars.

3.2 Problem Formulation

In PTPS, Unit No. 7 having an output capacity of 250 MW is considered for energyAuditing Process. Energy Audit has been done for evaluating the performance of main Unit and also the performance of sub units like Boiler, Turbine and generator,Condenser & Heater are calculated, and compared their performance at differentoutput loads. The main problems, which are highlighted in PTPS Unit No. 7 are:

Energy efficiency has to be improved to survive in Global Market. To extend the life of units by 15 to 20 years To restore original rated capacity of the units.

To improve Plant availability/ load factor. To enhance operational efficiency and safety. To remove ash pollution and to meet up environmental standards.

3.3 History of Unit 7th

The unit was commissioned on coal firing on 28-09-2004 & dedicated on commercialrun w.e.f. 29-12-2004. The some of the main achievements of Unit 7 th are linedbelow:

i. Unit-7 th generated 1977.9204 MU (PLF 90.32%) during 2006-2007 which isthe highest generation from this unit after its commissioning.

ii. Monthly highest generation of Unit-7 th remained 189.034 MU (PLF 101.63%)during Jan.-2007, which is the highest during a month since commissioning of this unit.

iii. %age Aux. Consumption of Unit-7 th remained 8.44% during this FY. Earlierlowest Aux. Consumption was 9.76% during 2004-2005

iv. Specific coal consumption of Unit-7 th remained 0.628 Kg/Kwh during this FY,which is the lowest since its commissioning.

v. The Heat Rate of Unit-7 th remained 2507 Kcal/kwh, which is the lowest sincecommissioning of the unit.


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vi. Unit-7 th (250 MW) remained in continuous operation from 11-01-2007/2130Hrs to 08-03-2007/1555 Hrs (55 Days 18 Hrs 25 Mts), which is the highestcontinuous running since commissioning the Unit.

3.4 Data Collection

The data for the auditing purpose is collected from the experimental work. Theexperimental work is done at different output loads [250 MW, 232 MW, 210 MWrespectively] and summarized in tables below. The Table 2, 3 and 4 shows the data of thermal power plant at different loads of 250 MW, 232 MW, 210 MW respectively.

Table No.2 Data for Thermal Power Plant at Output load 250 MWSr.No.

Description Condition Pr.bar

Tem.0C

FlowT/Hr

EnthalpyKJ/Kg

EnergyMW

1 Steam Inlet HPT SuperheatSteam 150 540 782 3414.6 741.73

2Steam Outlet HPT

andInlet Re-heater

SuperheatSteam 38 340 710 2574.6 507.77

3 Steam Outlet Re-heater and inlet IPT

SuperheatSteam

38 540 710 3414.6 673.43

4 Steam Outlet IPTand inlet LPTSuperheat

Steam 8 340 630 2574.6 450.56

56th Extraction HPT

and inlet HPH6Superheat

Steam 38 340 70 2574.6 50.06

6 HPH6 Outlet andInlet HPH5 Water 24 210 70 2028.6 39.45

75th Extraction IPT

and Inlet HPH5Superheat

Steam 18 430 46 2952.6 37.73

8 HPH5 Outlet andInlet Dearator Water 7 200 125 1986.6 68.98

9 3rd Extraction IPTand Inlet LPH3 SuperheatSteam 9 311 26 2452.8 17.71

10 Drip Outlet LPH3and Inlet LPH2 Water 123 1663.2

11 2nd Extraction LPTand Inlet LPH2Superheat

Steam 1.6 213 22 2041.2 12.47

12 Drip Outlet LPH2and Inlet LPH1 Water -0.6 125 1671.6

13 1st Extration LPTInlet LPH1Superheat

Steam -1.8 98 28 1558.2 12.12

14Drip Outlet LPH1and Inlet to Hot-

wellWater 50 1356.6

15 Exhaust SteamOutlet LPTSuperheat

Steam 0.09 45 530 1335.6 196.63

16 Condenser Outlet &Inlet Hot-well

Water 0.1 36 530 1297.8 191.06

17 Condensed SteamInlet to LPH1 Water 11.8 50 652 1356.6 245.69

18Condensate Outlet

LPH1 andInlet LPH2

Water 11.8 72 652 1449 262.43


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19Condensate OutletLPH2and Inlet LPH3

Water 11.26 92 6521533 277.64

20Condensate OutletLPH3 and InletDearator

Water 9.8 120 6521650.6 298.94

21 BFP Inlet Water 18.4 163 786 1831.2 399.8122

Condensate InletHPH5 Water 188 167 786 1848 403.48

23Condensate OutletHPH5 and InletHPH6

Water 187 202 7861995 435.58

24Condensate OutletHPH6 and InletEconomizer

Water 183 242 7862163 472.26

25Feed Water InletDrum Water 174 250 786

2196.6 479.5926 Steam Inlet LTSH Steam 160 355 786 2637.6 575.88

27 Steam Inlet PlatenSH Steam 786 1146.6 250.34

28 Steam Inlet FinalSuper Heater Steam 145 538 786 3406.2 743.69

29 Flue Gas Inlet Re-heater Flue Gas -22 740 880 4254.6 1040.01

30 Flue Gas Inlet FinalSuper Heater Flue Gas -19.2 650 880 3876.6 947.61

31 Flue Gas InletPlaten Super-heater Flue Gas -0.1 1120 880 5850.6 1430.15

32Flue Gas InletLTSH Flue Gas -1.1 916 880 4993.8 1220.71

33Flue Gas InletEconomizer Flue Gas -0.7 456 880 3061.8 748.44

34 Flue Gas Inlet APH Flue Gas -1.8 296 880 2389.8 584.1735 Flue Gas To Stack Flue Gas 0.15 149 880 1772.4 433.2536 SA Inlet APH Air 250 295 880 2385.6 583.1537 SA Inlet Boiler Air 250 290 900 2364.6 591.1538 PA Inlet APH Air 800 36 150 1297.8 54.0839 PA Inlet Boiler Air 700 278 150 2314.2 96.43

40 Coal Supply toBoiler Coal 120 1146.6 38.22

41Cold Water Inlet toCondenser Water 7 30 45000 1272.6

15907.50

42

Hot Water Outlet

FromCondenser

Water 6 38 450001306.2

16327.50


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Table 3 Data of Thermal Power Plant at output load 232 MWSr.No.

Description Condition Pr.bar

Tem.0C

FlowT/Hr

EnthalpyKJ/Kg

EnergyMW

1 Steam Inlet HPTSuperheat

Steam 141 534 735 3389.4 692.01

2

Steam Outlet HPT

andInlet Re-heater

SuperheatSteam 35 340 675 2574.6 482.74

3 Steam Outlet Re-heater and inlet IPTSuperheat

Steam 33 533 675 3385.2 634.73


Steam 6 350 600 2616.6 436.11

5 6th Extraction HPTand inlet HPH6

SuperheatSteam

34 330 60 2532.6 42.22

6 HPH6 Outlet andInlet HPH5 Water 20 205 60 2007.6 33.47

7 5th Extraction IPTand Inlet HPH5Superheat

Steam 15 420 40 2910.6 32.34

8 HPH5 Outlet and

Inlet DearatorWater 6.5 171 100 1864.8 51.8

9 3rd Extraction IPTand Inlet LPH3Superheat

Steam 8 303 20 2419.2 13.45

10 Drip Outlet LPH3and Inlet LPH2

Water

11 2nd Extraction LPTand Inlet LPH2Superheat

Steam 1.4 218 17 2062.2 9.73

12 Drip Outlet LPH2and Inlet LPH1

Water 120 1650.6

13 1st Extraction LPTInlet LPH1Superheat

Steam -1.5 97 23 1554 9.93

14Drip Outlet LPH1and Inlet to Hot-well

Water 47 1344


Steam 0.08 45 505 1335.6 187.36

16 Condenser Outlet &Inlet Hot-well

Water 0.08 40 505 1314.6 184.41

17 Condensed SteamInlet to LPH1 Water 11 45 600 1335.6 222.6

18Condensate OutletLPH1 andInlet LPH2

Water 10.5 71 600 1444.8 240.8

19Condensate OutletLPH2 and Inlet

LPH3

Water 10 89 600 1520.4 253.41


Water 8.6 117 600 1638 273.01

21 BFP Inlet Water 16 160 718 1818.6 362.7

22 Condensate InletHPH5 Water 172 161 718 1822.8 363.54

23Condensate OutletHPH5and InletHPH6

Water 171 196 718 1969.8 392.87


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Water 168 238 718 2146.2 428.04

25Feed Water InletDrum Water 160 246 718 2179.8 434.74

26 Steam Inlet LTSH Steam 156 351 718 2620.8 522.69

27 Steam Inlet PlatenSH Steam 718

28 Steam Inlet FinalSuper Heater Steam 141 532 718 3381 674.3

29 Flue Gas Inlet Re-heater

Flue Gas -10 635 800 3813.6 847.46

30 Flue Gas Inlet FinalSuper Heater Flue Gas -7 620 800 3750.6 833.46

31Flue Gas InletPlatenSuper-heater

Flue Gas -0.08 950 800 5136.6 1141.46

32Flue Gas InletLTSH Flue Gas -0.4 861 800 4762.8 1058.39

33 Flue Gas InletEconomizer Flue Gas -0.65 433 800 2965.2 658.93

34 Flue Gas Inlet APH Flue Gas -0.8 294 800 2381.4 529.1935 Flue Gas To Stack Flue Gas 0.143 147 800 1764 39236 SA Inlet APH Air 240 292 800 2373 527.3337 SA Inlet Boiler Air 240 272 850 2289 540.4638 PA Inlet APH Air 615 36.5 142 1299.9 51.2739 PA Inlet Boiler Air 615 292 142 2373 93.60

40 Coal Supply toBoiler Coal 114

41 Cold Water Inlet toCondenser Water 6 30 40000 1272.614139.9

9

42Hot Water OutletFromCondenser

Water 5 37 40000 1302 14466.67

Table 4 Data of Thermal Power Plant at load 210 MWSr.No. Description Condition

Pr.bar

Tem.0C

FlowT/Hr

EnthalpyKJ/Kg

EnergyMW

1 Steam Inlet HPTSuperheat

Steam135 530 685 3372.6 641.73

2Steam Outlet HPTandInlet Re-heater

SuperheatSteam

33 338 635 2566.2 452.65

3 Steam Outlet Re-

heater and inlet IPT

Superheat

Steam

32 530 635 3372.6 594.89


Steam5 338 565 2566.2 402.75

5 6th Extraction HPTand inlet HPH6

SuperheatSteam

32 328 48 2524.2 33.66

6 HPH6 Outlet andInlet HPH5 Water18 200 48 1986.6 26.49

7 5th Extraction IPTand Inlet HPH5Superheat

Steam12 412 26 2877.0 20.78


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8 HPH5 Outlet andInlet Dearator Water6 156 80 1801.8 40.04

9 3rd Extraction IPTand Inlet LPH3Superheat

Steam7 295 16 2385.6 10.60

10 Drip Outlet LPH3and Inlet LPH2 Water0.0 0.00

11 2nd Extraction LPTand Inlet LPH2 SuperheatSteam 1.2 205 15 2007.6 8.37

12 Drip Outlet LPH2and Inlet LPH1 Water115 1629.6 0.00

13 1st Extraction LPTInlet LPH1

SuperheatSteam

-1.2 95 18 1545.6 7.73

14Drip Outlet LPH1and Inlet to Hot-well

Water46 1339.8 0.00


Steam0.07 44 475 1331.4 175.67

16Condenser Outlet &Inlet Hot-well Water

0.07 38 475 1306.2 172.35

17 Condensed SteamInlet to LPH1 Water10.5 43 550 1327.2 202.77

18Condensate OutletLPH1 andInlet LPH2

Water10.5 70 550 1440.6 220.09

19Condensate OutletLPH2 and InletLPH3

Water9.5 87 550 1512 231.00


Water8.2 115 550 1629.6 248.97

21 BFP Inlet Water 15 158 650 1810.2 326.84

22Condensate InletHPH5 Water

166 159 650 1814.4 327.60

23Condensate OutletHPH5and InletHPH6

Water165 190 650 1944.6 351.11


Water160 234 650 2129.4 384.48

25 Feed Water InletDrum Water154 244 650 2171.4 392.06

26 Steam Inlet LTSH Steam 150 345 650 2595.6 468.65

27 Steam Inlet PlatenSH

Steam 650 0 0.00

28 Steam Inlet FinalSuper Heater Steam 138 527 650 3360 606.67

29Flue Gas Inlet Re-heater Flue Gas

-8 610 760 3708.6 782.93

30 Flue Gas Inlet FinalSuper Heater Flue Gas-6 600 760 3666.6 774.06

31Flue Gas InletPlatenSuper-heater

Flue Gas-0.06 900 760 4926.6 1040.06

32 Flue Gas Inlet Flue Gas -0.2 840 760 4674.6 986.86


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LTSH

33Flue Gas InletEconomizer Flue Gas

-0.58 423 760 2923.2 617.12

34 Flue Gas Inlet APH Flue Gas -0.6 292 760 2373 500.9735 Flue Gas To Stack Flue Gas 0.13 145 760 1755.6 370.6336 SA Inlet APH Air 230 292 760 2373 500.97

37 SA Inlet Boiler Air 230 65 790 1419.6 311.5238 PA Inlet APH Air 550 36 130 1297.8 46.8739 PA Inlet Boiler Air 550 277 130 2310 83.42

40 Coal Supply toBoiler Coal110 0 0.00

41 Cold Water Inlet toCondenser Water5 30 35000 1272.6 12372.5

0

42 Hot Water OutletFrom Condenser Water4 36 35000 1297.8 12617.5

0

Note: In Table 2,3 & 4, the value of energy is calculated from the formula given as:Energy = Flow (Kg/Sec.) * Enthalpy (KJ/Kg)/1000

4.0 Data AnalysisIn this step, the data, which is collected from Power Plant Unit No.7 & at differentoutput load, is analyzed. Firstly from the data of Thermal Power Plant running at theload of 250MW or full output load given in Table 2 is considered for the analysispurpose. The data analysis work is as below:Step 1: Boiler Section Inlet in Boiler

(i) Coal Inlet [40] = 120T/hr = 120 x 1000/3600 = 33.33 Kg./Sec. Calorific Value of Coal = 4860 K Cal/KgTherefore, Energy = 4860 x 33.33 x 4.2/1000 = 680.33 MW

(ii) Reheated Steam Inlet Energy [2] = 507.77 MW

(iii)Inlet from Economizer Steam Energy [24] = 472.26 MWTotal Inlet = (i) + (ii) + (iii) = 680.33 + 507.77 +472.26 = 1660.36 MW Outlet from Boiler

(iv) Steam Inlet HPT Energy [1] = 741.73 MW(v) Steam Outlet From Reheated Energy [3] = 673.44 MW (vi) Flue Gases = Generally not taken in considration

Total Outlet = (iv) + (v) + (vi) = 741.73 + 673.44 + 0 = 1415.17 MWLoss in Boiler = Inlet Outlet = 1660.36 1415.17 = 245.19 MWEfficiency of Boiler = 1415.17 x 100/ 1660.36 = 85.23 %Step2: Section Turbine & Generator Section(i) HPT Inlet [1] = 741.73 MW(ii) HPT Outlet [2] + Extraction HPT [5] = 507.77 + 50.06 = 557.83 MW

Net Energy at HPT = (i) - (ii) = 741.73 557.83 = 183.9 MW (iii) IPT Inlet [3] = 673.44 MW (iv) IPT Outlet [4] + Extraction IPT [7] = 450.55+37.73 = 488.28 MW

Net Energy at IPT = (iii)- (iv) = 673.44 488.28 = 14.84 MW (v) LPT Inlet [4] = 450.56 MW (vi) LPT Outlet [9] + Extraction LPT [11] + Inlet LPH [13] =17.71+12.47 +12.12

= 42.3 MWNet Energy at LPT = (v) (vi) = 450.56 42.3 = 408.26 MW

Net Input at Turbine (HPT, IPT & LPT) = 183.9 + 14.84 + 408.26 = 607 MW


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Efficiency of Turbo Generator = 250 x 100/ 607 = 41.19 % Step 3: Section Condenser:Condenser Efficiency = Actual Cooling Water Temp rise

Max Possible Temp. Rise= Water Outlet Temp. [42]- Water temp. at Inlet to condenser [41] * 100

Exhaust Steam Temp. [15] Water temp. at Inlet to condenser [41]

= (38 30) x100 = 53.33 %

45 30

Step 4: Section Heaters (LP & HP)LPH1 Effectiveness = T [18] T [17] = 72 50 = 0.46

T [13] T [17] 98-50LPH2 Effectiveness = T [19] T [18] = 92 72 = 0.14

T [11] T [18] 213-72LPH3 Effectiveness = T [20] T [19] = 120-92 = 0.13

T [9] T [19] 311-92HPH5 Effectiveness = T [23] T [22] = 202-167 = 0.13

T [7] T [22] 430-167HPH6 Effectiveness = T [24] T [23] = 242-202 = 0.29

T [05] T [23] 340-202Overall Unit Efficiency = Output of Station x 100

Input of Station

= Energy sent out (KW) .Fuel burnt (Kg) x Calorific value of fuel (K Cal/kg)

= 250 x 100 = 36.74 %680.33

Similarly, the data of plant running at output load of 232 MW & at 210 MW isanalyzed and the results are shown in Table 5.

Table 5 Analyze data for the plant running at 232 MW & 210 MW

Boiler SectionDescription At 232 MW At 210 MWInlet in Boiler 1557.23 MW 1460.72 MWOutlet from Boiler 1326.74 MW 1236.62 MWLoss in Boiler 230.49 MW 224.1 MWEfficiency of Boiler 85.20 % 84.66 %

Section Turbine &Generator Section

Net Energy at HPT 167.05 MW 155.42 MWNet Energy at IPT 166.28 MW 171.36 MWNet Energy at LPT 403.08 MW 376.03 MWNet Input at Turbine 736.41 MW 702.81 MWEfficiency of Turbo Generator 31.50 % 29.88 %

Section Condenser Condenser Efficiency 46.67 % 42.86 %Section Heaters(LP & HP)

LPH1 Effectiveness 0.50 0.51LPH2 Effectiveness 0.12 0.12LPH3 Effectiveness 0.13 0.13HPH5 Effectiveness 0.13 0.12HPH6 Effectiveness 0.31 0.33

Overall station efficiency 35.89% 33.67%


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Now, from the data calculated for analysis purpose above is used for finding theproblems and their recommendations. The above data is summarized in Table 6.

Table 6 Analyzed data for different parameters of the plant running at various load

On the data in Table 6, parato diagram is made, which is more helpful to find theexact status of the plant. Figure 1 shows the Efficiencies comparison between thevarious plant output levels in term of Boiler Efficiency, Turbine & Generator Efficiency& Condenser Efficiency. Figure 2 & 3 shows the Effectiveness value for the heaters at variousoutput level & finally the Figure 4 shows the comparison between overall plant efficiency atvarious output level.

0.00%

10.00%

20.00%

30.00%

40.00%

50.00%

60.00%

70.00%

80.00%

90.00%

E f f i c i e n c y

V a

l u e

BoilerEfficiency

Turbine &GeneratorEfficiency

CondenserEfficiency

Efficiency

Various ef ficiencies comparision for plant running at variousoutput values

Figure 1 Parato Analysis for various efficiencies for plant running at various outputvalues

S. No. Description 250MW 232MW 220 MW1 Boiler Efficiency 85.23% 85.20% 84.66%2 Turbine & Generator Efficiency 41.19% 31.51% 29.88%3 Condenser Efficiency 53.33% 46.67% 42.86%4 Heater LPH1 Effectiveness 0.46 0.50 0.515 Heater LPH2 Effectiveness 0.14 0.12 0.126 Heater LPH3 Effectiveness 0.13 0.13 0.137 Heater HPH5 Effectiveness 0.13 0.13 0.128 Heater HPH6 Effectiveness 0.29 0.31 0.339 Overall Plant Efficiency 36.74% 35.89% 33.67%10 Coal Consumption 120 T/Hr 114 T/Hr 110 T/Hr


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0

0.1

0.2

0.3

0.4

0.5

0.6

E f f r c

t i v e n e s s

V a

l u e

H e a

t e r

L P H 1

H e a

t e r

L P H 2

H e a

t e r

L P H 3

Heaters Detail

Heater Effectiveness values for various output values

Series1

Series2

Series3

Figure 2 Parato Analysis for Heaters Effectiveness Values

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

E f f e c

t i v e n e s s

V a l u e

HeaterHPH5

HeaterHPH6

Heaters Detail

Heater Effectivene ss value for Various Output Values of thePlant

Figure 3 Parato Analysis for Heaters Effectiveness Values


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32.00%

32.50%

33.00%

33.50%

34.00%

34.50% 35.00%

35.50%

36.00%

36.50%

37.00%

P l a n

t E f f i c i e n c y

i n

( % a g e )

At250MW

At 232MW

At210MW

Plant Output Detai l

Overall Plant Efficiency at Various Output Level

Figure 4 Parato Analysis for Overall Plant Efficiency

5.0 RESULTS & RECOMMENDATIONS

From the analysis part of this work, it is concluded that the overall plant efficiencyvaries with the variation or small change in the output loads. From the experimentalwork done in above steps shows that as the output load is lower the efficiency of totalunit is low. Output Load of the plant always depends upon the requirements forconsumption of energy. As the energy consumption decreases, Plant has to be startingto run at lower load and the overall performance is also lower, because energy cannotbe stored. On the other hand if the Plant or Unit can run at Full Output Load or 250MW load the performance is higher. Some of the recommendations based on this

research work are made for increasing the performance of the plant is shown in Table7.


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Table 7 Recommendation for increasing Plant Efficiency

BoilerSection

Description Recommendation

Boiler Efficiencycan increased upto90 % to 95 %

1. By increasing the oxygen content of thecoal, result in reduced level of heatingvalve

2. Boiler efficiency is mainly attributed to dryflue gas, wet gas & sensible heat loss sothat by reducing the flue gas exhausttemperature.

3. Periodic maintenance of boiler like:(a) Periodical cleaning of boiler.(b) Proper water treatmentprogrammes and blow down control.(c) Excess air control.(d) Percentage loading of boiler.(e) Steam generation pr. andtemperature.(f) Boiler insulation(g) Quality of fuel.

Condenser

Low condenservacuum due to:-(a) Air ingress in

the condenser.(b) Dirty tubes.(c) Inadequate

flows of CondensateWater incondenser.

(i) Cooling Water flow must be checkedfor correct quantity.

(ii) Condenser tubes must be cleanedregularly.

(iii) Vacuum drop must be cleanedregularly. CW pumps impeller must bechecked for erosion.

(iv) Air ingress must be arrested.(v) Improvement in quality of cooling water

and close cycle.

Overall

PlantEfficiency

Overall efficiency of plant can beincreased

By using wash-coal, which will save theenergy from waste with ash.

6.0 REFERENCES & BIBLIOGRAPHY

1.Raask, E Lo, K.L. & Song E, Z. M.(1969), Tube Failures Occurring in the primarysuper heaters and reheaters and in the economizers of coal fired boilers, EnergyConservation in Coal fired boilers , Vol.12, 1969, Page No. 185.

2. Rajan G.G. (2001), Optimizing Energy efficiency in industries by Energy LossControl-models, Chapter-14, Page No. 276.

3.Pilat, J., Micheel P. A. (1969) Source test Cascade impactor for measuring the size

ducts in boilers, Energy Conservation in Coal fired boilers, Vol. 10, Page No.410-418.

4.Schulz, E., Worell, E. & Blok, K. (1974) Size distribution of submissionparticulars emitted from Pulverized coal fired plant Energy Conservation in CoalFired boilers, Vol. 10, Page No.74-80.

5.Neal, P.W.Lo, K.L. (1980) Conventional automatic control of boiler outlet steampressure Energy Conservation in Coal fired boilers, Vol. 16, Page No.91-98.


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6.Dognlin, Chen James, D & Varies B.de (2001), Review of current combustion,technologies for burning pulverized coal, Energy conservation in coal fired boilersVol.48, Page No. 121-131.

7.Bergander, Mark J. Porter, R.W. (2003), Most troublesome component of electricpower generation plant, Energy conservation in coal fired boilers, Vol. 32, PageNo. 142-149.

8.Hatt, Roderick, M. & Lewis, W (2003), Coal ash deposits in coal fired boilersEnergy conservation of coal fired boilers, Vol. 14, Page No. 181-189.

9. Central Electricity Generating Board, Modern Power Station Practice (Operation& Efficiency), Pergamon Press Oxford, New York. 2 nd Edition, Volume-7.

10. P.K.Nag Power Plant Engineering Tata McGraw-Hill Publishing CompanyLimited New Delhi. 2 nd Edition.

comparing the thermal power plant performance at various output loads by energy auditing (a...

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