Energy and Exergy Analysis of a 250 mw Coal Thermal Power Plant at Design Load Conditions

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1 Energy and Exergy Analysis of a 50 mw Coal Thermal Power Plant at Design oad Conditions Rakesh Kumar, Ajay Berry, Dr. Mahesh Kumar 3, Himanshu Manchanda 4, 3, 4 Assistant Professor, Mechanical Engineering Department, GJUS&T Hisar (India)-500. Research Scholar, Mechanical Engineering Department, GJUS&T Hisar (India)-500. Abstract: In this research work thermodynamic analysis of 50 MW Panipat coal thermal power plants has been carried out by using an energy and exergy analysis method at design load conditions. The exergy analysis of a power plant deals with the analysis of energy on the basis of quantity only however the energy analysis deals with the analysis of energy on the basis of quantity as well as quality. The aim of present research work is to conduct an energy and exergy analysis of the major components of a coal thermal power plant like boiler, turbine, and condenser and pump in order to identify the magnitude and location of real energy efficiency. The temperature and pressure of main stream and the condenser pressure are considered as operating parameters. From the study it is observed that the major contribution of energy efficiency is found in pump of 94.56% followed boiler of about 87.% and condenser of 59.67%. The major exergy efficiency is found in the pump of 9.9% followed by turbine of 5.33% and condenser of 3.40% of the total exergy supplied. Keywords: Exergy; Energy; Thermal power plant; Energy efficiency; Exergy efficiency. I. INTRODUCTION The panipat thermal power station (PTPS) is fully operated by Haryana power generation corporation limited (HPGC) as it is wholly owned by the state government of Haryana under the Ministry of power (Government of India). Panipat Thermal Power Station was a designated consumer in the state of Haryana, under management of HPGC. HPGC was incorporated as company on 7 March 997 but it came existence on 4 August, 998 and given the responsibility of operating and maintenance of state own power generating plant and projects. Currently, it had six power station and project situated at panipat, Yamuna Nagar, Hisar and Jhajjar districts []. Fig.Photographic view of panipat thermal power plant PTPS is the major coal based and first power station installed in the Haryana by the HPGC. The plant is located at village Assan which is KM away from the city. Total present installed capacity of the power plant 360MW in six stages as given in the table. Table.Year wise installed capacity of PTPS. Stage Unit Capacity Date of installation Stage- Unit- 0MW Unit- 0MW

2 Stage- Stage-3 Stage-4 Unit-3 0MW Unit-4 0MW Unit-5 0MW Unit-6 0MW Stage-5 Unit-7 50MW Stage-6 Unit-8 50MW Transportation of coal is done by wagons. PTPS draws water from right main canal through an intake channel to meet its water requirement. The primary fuel input to the plant is coal which is taken from Jhariya and Raniganj Mines. PTPS disposes bottom ash to the nearest ash pond in slurry form and the dry fly ash to the nearby cement industries and fly ash traders []. The project detail of PTPS is given in table. Table.Project detail of PTPS Sponsor HPGC Name Panipat thermal power station(ptps) ocation Assan village, panipat district, Haryana Source of financing Government of India Plant capacity 360MW (4x0+x0+x50 MW) Total unit 8 Type Coal based thermal power plant Coal source Jhariya and Raniganj mines Water source Canal through Plant area 660 acres Colony 400 acres Ash storage & Raw water 940 acres The schematic view of important major components of a thermal power plant, namely, boiler, turbine, condenser and pump are shown in figure,3,4 and 5 respectively. Fig. Schematic view of boiler. 075

3 Fig.3. Schematic view of turbine Fig. 4. Schematic view of condenser Fig. 5. Schematic view of CEP pump. THERMA MODEING AND FORMUAE USED The energy and exergy analysis of a thermal power plant is studied by using the basic thermodynamics laws. The energy analysis of the thermal power plant has been evaluated by the st law and the exergy analysis of thermal power plant studied by the nd law of thermodynamic [3]. The energy and exergy analysis of a thermal power plant mainly depend upon the major working components like boiler, turbine, condenser and pump. A. Energy and exergy analysis boiler The specifications and the operating parameters of boiler are given in table 3 and

4 Type Running Authority Mode of heat transfer Table 3.Specification of boiler Water-tube BHE Natural circulation and sub-critical Table 4.Operating parameter of the boiler Parameter Unit Input Output Mass flow TPH Temperature Celsius Pressure Bar Enthalpy kj/kg Entropy kj/kg-k The proximate and ultimate analysis of lignite coal is given in table5 and 6. Table5.Proximate analysis of coal. Coal contents Units Value Fixed carbon % Volatile matter % 30 Moisture % 5 Ash contents % 34 Calorific value of coal Kcal/kg 4000 Calorific value of carbon Kcal/kg Table 6.Ultimate analysis of coal Coal constituents Units Value Carbon % Hydrogen %.84 Nitrogen % 0.76 Oxygen % 7. Sulphur % 0.35 CO % 4.5 Ambient temperature Surface temperature of boiler 0 C 3 0 C 35 ) Energy analysis of boiler; The energy analysis of the boiler can be carried out by using the equation,, 3, 4, 5, 6 and 7 respectively [4-8]. Unburnt carbon loss ( ) Where: U c = Total unburnt carbon in ash CV c = Calorific value of carbon GCV= Gross calorific value of carbon Dry flue gas loss ( ) UC CVC 00 GCV () 077

5 Where:M f = Mass of flue gases C p = Specific heat capacity T g = Temperature of flue gas T a = Ambient Temperature oss due to moisture in fuel ( 3 ) Where:M= Total mositure in fuel oss due to hydrogen in fuel ( 4 ) Where: H= Hydrogen percentage oss due to moisture in air ( 5 ) International Journal for Research in Applied Science & Engineering Technology (IJRASET) M Where: AAS= Actual mass of air supplied C p steam = Specific heat capacity steam oss due to radiation ( 6 ) 6 Ts Where: T s = Temperature of boiler surface V m = Wind velocity M f Cp Tg Ta 00 GCV 584 Cp T g Ta 00 3 GCV 9 H 584 C GCV p g a 4 5 T T 00 AAS humidity factor Cp steam Tg Ta 00 GCV 4 Ta Ts T a (3) Vm Heat loss due to unmeasured loss in boiler ( 7 ) Total losses = (7) Boiler efficiency = 00-Total losses ) Exergy analysis of boiler: The exergy of boiler in the form of the superheated steam, which is produced with the help of hot flues gasses to convert the water into the steam. The parameters used for exergy efficiency of boiler are given in table 7. Table 7.Working parameters of boiler Substance Mass flow rate(tph) Temperature ( o C) Fuel (coal) Water Air supplied Steam Flue Gasses () (4) (5) (6) The exergy analysis of boiler can be carried out by using the equation 8, 9, 0,,, 3 and 4 respectively [9]. 078

6 Exergy of fuel ( ) f C.95 N H S 365. O f Where: C= Carbon N= Nitrogen H= hydrogen S= Sulpher O=Oxygen Exergy of feed water ( ) Where C w p T C T T T l w p w = Specific heat of water T w = Temperature of feed water T w = Referance temperature Exergy of air supply ( a ) ε a C Where C pa = Specific heat of air T a = Temperature of air supplied Exergy of steam formed ( s ) s pa w n T T T T T l a a ο ο n h h T S S Where h= Enthalpy of outlet steam h 0 = Enthalpy referance temperature Exergy of flue gasses( ) Where ε g g C pg C pg =specific heat of flue gas T ο Tg T g Tο Tοln The total irreversibility in the steam boiler is given by = Total exergy entering the boiler Total exergy leaving the boiler b I b Exergy efficiency ( nd law efficiency) of boiler total exergy leaving the boiler total exergy entering the boiler f s g T ο (8) (9) (0) () () (3) 079

7 s g f (4) B. Energy and exergy analysis turbine The specifications of turbine and operating parameters are given in table 8, 9, 0,,, 3 and 4 respectively. Table 8. Specification of turbine Type 3-Cylinder mixed flow Tanden Capacity 50MW Speed 3000 rpm Overall length 6.975m Width 0m Stage 3 ) Energy analysis of turvine Energy enters in the turbine in the form of the thermal energy of superheated steam coming from the boiler. Thermal power plant turbine consists of three sections of turbine which are HP Turbine (High pressure turbine) IP Turbine (Intermediate pressure turbine) P Turbine (low pressure turbine) a) HP Turbine Table9. Parameter used for efficiency calculation HP turbine Parameter Units Input Output Steam flow TPH Pressure Bar Temperature celsius Enthalpy kj/kg Entropy kj/kg-k The energy analysis of turbine can be calculated by using equation 5, 6, 7 and 8 respectively [0]. Isentropic energy efficiency Actual Work Isentropicefficiency Iesentropic efficiency Ideal work h h h h a s h = Enthalpy at inlet of HP turbine h a = Enthalpy at outlet of HP turbine h s = Isentropic enthalpy of HP turbine b) IP Turbine (5) Table 0.Parameter used for efficiency calculation HP turbine Parameter Units Input Output Steam flow TPH Pressure kg/cm Temperature Celsius Enthalpy kj/kg Entropy kj/kg-k

8 Isentropic energy efficiency Iesentropi c efficiency h h h h Iesentropi a s h =Enthalpy at inlet of IP turbine h a =Enthalpy at outlet of IP turbine h s = Isentropic enthalpy of IP turbine Actual Work c efficiency Ideal work (6) c) P Turbine Table Parameter used for efficiency calculation HP turbine Parameter Units Input Output Steam flow TPH Pressure Bar Temperature Celsius Enthalpy kj/kg Entropy kj/kg-k Isentropic energy efficiency Iesentropic efficiency Actual Work Iesentropic efficiency Ideal h h h h a s work h =Enthalpy at inlet of P turbine h a =Enthalpy at outlet of P turbine h s = Isentropic enthalpy of P turbine The energy efficiency of whole turbine is given by the T H I (8) ) Exergy analysis of turbine:theexergy of the turbine in the form of work done (electric generator), which is being converted from the thermal energy of steam. Thermal power plant turbine consists of three sections of turbine which are HP Turbine (High pressure turbine) IP Turbine (Intermediate pressure turbine) P Turbine(low pressure turbine) a) HP Turbine Table Parameter used for exergy efficiency of HP turbine Parameter Units Input Output Steam flow TPH Pressure Bar Temperature Celsius Enthalpy kj/kg Entropy kj/kg-k Exergy kj/kg (7) 08

9 The exergy analysis of turbine can be calculated by using equation 9, 0,,, 3, 5, 6, 7 and 8 respectively []. Exergaticefficiency b) IP Turbine Exergy Recovered Exergy Supplied TS gen. Entropy Generation( S ) gen. ( h h0 ) T0 ( S S0) Ψ =exergy at inlet Ψ =exergy at outlet S S Table 3Parameter used for exergy efficiency of IP turbine Parameter Units Input Output Steam flow TPH Pressure Bar Temperature Celsius Enthalpy kj/kg Entropy kj/kg-k Exergy kj/kg The exergy analysis of turbine can be calculated by using equation 8, 9, 0,,, 3 and 4 respectively [-]. (9) (0) () Exergy Recovered Exergatic efficiency Exergy Supplied c) P Turbine TS gen. Entropy Generation( S ) gen. ( h h0 ) T0 ( S S0) Ψ =exergy at inlet Ψ =exergy at outlet S S () (3) (4) Table 4.Parameter used for exergy efficiency of P turbine Parameter Units Input Output Steam flow TPH Pressure Bar Temperature Celsius Enthalpy kj/kg Entropy kj/kg-k Exergy kj/kg

10 Exergy Recovered Exergatic efficiency Exergy Supplied TS gen. Entropy Generation( S ) gen. ( h h0 ) T0 ( S S0) S Ψ =exergy at inlet Ψ =exergy at outlet Exergy efficiency of complete turbine is given by the T H I S (5) (6) (7) (8) C. Energy and exergy analysis condenser The specifications and operating parameters of condenser are given in table 5 and 6. Table 5.Specification of condenser Type Surface type made of fabricated single head Area 96.55cm Cooling water flow rate 450 TPH ) Energy analysis of condenser: Energy entered in the condenser in the form wet steam. Table 6.Parameter used for the efficiency calculation of condenser Parameters Unit Inlet Outlet Mass flow TPH Pressure Bar Temperature Celsius Enthalpy kj/kg Entropy kj/kg-k Exergy kj/kg Cooling tower Temperature Celsius Water flow TPH The energy analysis of condenser can be calculated by using equation 9, 30 and 3 respectively []. Mass balance of condenser is Energy loss m h h Q in in out K First law efficiency of condenser is given by the formula QK m h h Q k in mc p in dt out m= water flow in the cooling water m in = water inlet in condenser Q k =heat loss in condenser h in = enthalpy of inlet saturated steam (9) (30) (3) 083

11 h out = enthalpy of out let condensate water dt= terminal temperature difference of cooling tower ) Exergy analysis of condenser :Exergy out from the condenser is the form of condensate water. The exergy analysis of condenser can be calculated by using equation 3, 33 and 34 respectively []. Mass balance of condenser is given by T T S m 0 gen in in out Qin Tout nd law efficiency of condenser is given by the formula I destroyed m Q in in T out 0 in T out (34) min in out T out =temperature at the outlet of condenser Ψ in = exergy inlet in the condenser Ψ out = exergy inlet in the condenser D. Energy and exergy analysis pump The specifications and operating parameters of condenser are given in table 7 and 8. Table 7Specification of CEP pump Type of motor Induction type Speed 483rpm Power 35 kw Quantity 3 Table 8Parameter used for the calculation of CEP efficiency Parameters Unit Inlet Outlet Mass flow TPH Temperature Celsius Pressure KPa Enthalpy kj/kg Entropy kj/kg-k E. Energy analysis of pump Energy entered by the pump in the form of power of electric motor. The energy analysis of pump can be calculated by using equation 3and 3 respectively []. (3) (33) Iesentropi c efficiency h p h s a Iesentropi c efficiency h h Idealwork ActualWork (35) ) Exergy analysis of pumpexergy out from the pump in the form pressurized water. 084

12 Exergy Recovered Exergetic efficiency Exergy Supplied TS h h gen. I. RESUT AND DISCUSSION A. Results for the energy and exergy analysis of boiler The energy analysis of the boiler can be carried out by using the equation,, 3, 4, 5, 6 and 7 are as follows: Unburnt carbon loss kj / kg kj / kg Dry flue gas loss heat lossduetounburnt Carbon.504% heat lossdue to dry fluegases 4.98% oss due to moisture in fuel Heat lossdueto themositurein fuel.83% oss due to hydrogen in fuel Heat loss due to hydrogen in fuel % oss due to moisture in air Heat lossduetomoisturein air 0.698% oss due to radiation heat loss due to Radition 0.909% Heat loss due to unmeasured loss in boiler 7 = Total losses= =.8845% Boiler efficiency = % = 87.55% The results for the exergy analysis of boiler carried out by using equation 8, 9, 0,,, 3 and 4 are as follows: Exergy of fuel (36) 085

13 f f International Journal for Research in Applied Science & Engineering Technology (IJRASET) kj / kg Total Exergy of Exergy of feed water fuel 59.36MW l n 6.68kj / kg Total exergy of Exergy of air supply ε a ε a 305 feed water MW l n 5.669kj / kg 305 Total exergy of air supplieded 3.685MW s kj / kg s Total exergy of steam 97.56MW Exergy of flue gas ε g ε g l 43.3 n 0.533kj / kg Total exergy of 305 flue gas 6.739MW Exergy efficiency ( nd law efficiency) of boiler total exergy leaving the boiler total exergy entering the boiler Exergy efficiency of boiler= 47.43% Table 9 comparesion of energy and exergy analysis of boiler Result Energy 87.% Exergy 47.43% B. Results for the energy and exergy analysis of turbine The results for the energy analysis of turbine by using equation 5, 6, 7 and 8 are as follows: ) Energy efficiency of HP Turbine Energy efficiencyhpt( ) 86.50% ) Energy efficiency of IP Turbine 086

14 Energy efficiency of IPT ( ) 90.7% 3) Energy efficiency of P Turbine Energy efficiencyof PT ( ) 63.30% Table 0 Comparison of Energy analysis of different components of turbine Sr. No. Components Value. High Pressure Turbine(HPT) 86.50%. Intermediate Pressure Turbine(IPT) 90.7% 3. ow Pressure Turbine (PT) 63.30% The energy efficiency of total turbine is given by the T Total energy efficency of turbine( ) 49.63% T The results for the exergy analysis of turbine by using equation 9, 0,,, 3, 5, 6, 7 and 8 are as follows: a) Exergy efficiency of HP Turbine 300 ( ) ( ) b) Exergy efficiency IP Turbine Exergy efficiencyof Exergy c) Exergy efficiency of P Turbine Formula used for T 300 (37 ( efficiency HPT( ) 87.6% ) ) of IPT( 300( ) ( ) Exergy efficiencyof PT( ) 64.5% ) % Table.Exergy efficiency of different components of turbine Sr. No. Components Value. High Pressure Turbine(HPT) 87.6%. Intermediate Pressure Turbine(IPT) 94.69% 3. ow Pressure Turbine (PT) 64.5% Totalenergy efficency of turbine( T ) 5.33% Table. Comparison energy and exergy analysis of turbine RESUTS Energy 49.63% Exergy 5.33% 087

15 C. Results for the energy and exergy analysis of condenser The results for the energy analysis of condenser can be calculated by using equation 9, 30 and 3 are as follows: ( ) Energy efficiencyof condenser ( ) 59.67% The results for the exergy analysis of condenser calculated by using equation 3, 33 and 34 are as follows: (35. 30) Exergy efficiency of condenser =3.40% Table 3. Comparison of Energy and exergy analysis of condenser Result. Energy 58.89%. Exergy 34.69% D. Results for the energy and exergy analysis of pump The results for the energy analysis of pump by using equation 35 are as follows: p p % The results for the exergy analysis of pump by using equation 36 are as follows: % Table 4. Comparison of energy and exergy analysis of CEP pump Result. Energy %. Exergy 9.9% IV. CONCUSION This study presents the energy and exergy analysis of 50 MW Panipat coal thermal power plant. The temperature and pressure of main stream and the condenser pressure are considered as operating parameters. From the study it is observed that the major contribution of energy efficiency is found in pump of 94.56% followed boiler of about 87.% and condenser of 59.67%. The major exergy efficiency is found in the pump of 9.9% followed by turbine of 5.33% and condenser of 3.40% of the total exergy supplied. REFERENCES []. []. [3]. Cengel Y.A., Michael A. Thermodynamics an engineering approach. New Delhi; Tata MaGraw Hill: 006 [4]. Jegadeswaran, M.A., Daniel V.S., and Kanna, G.T., (05), Analysis for efficiency improvement and fuel savings opportunities in thermal power plant. International journal of science and technology, Vol. -3, pp: 9-5. [5]. Nighot, S.V.,Mr.Shende, A.S., Raghorte,G.S.,Prof.Dongre, S.S.,andUmak,V.V., (07), Study of boiler and thermal power plant station. International Journal on Research and Modern Trends in Engineering & Management (IJRMTEM), Vol.-,Issue- 088

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