Exergetic and energetic analysis of a 210 MW Thermal Power Plant in Pakistan

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1 Technical Jurnal, University f Engineering and Technlgy (UET) Taxila, Pakistan Vl. 22 N. I-27 Exergetic and energetic analysis f a 2 MW Thermal Pwer Plant in Pakistan,5 2 4,5 6 N. Husnain, W. A. Khan, S. R. Qureshi, F. A. Siddiqui, E. Wang, A. Mehmd Institute f Thermal Energy Engineering, Shanghai Jia Tng University, Shanghai-224, hina 2 Mechanical and Industrial Engineering Department, Majmaah University, Majmaah-952, Kingdm f Saudi Arabia Pakistan Navy Engineering llege, Natinal University f Sciences and Technlgy, Karachi-75 4 Engineering Science Department, University f Oxfrd. Parks Rad Oxfrd-OXPJ, United Kingdm 5 Mechanical Engineering Department, Bahauddin Zakariya University, Multan-68 6 Mechanical Engineering Department, University f Engineering and Technlgy Lahre (FSD ampus)-8 naveed69@sjtu.edu.cn Abstract-Exergetic analysis is a mdern tl t assess the ptimum thermal perfrmance f a pwer plant during design as well as during its peratinal perid. This apprach can identify the cmpnents f lw efficiency in the running plant and therefre suitable crrective actin can be applied t enhance the perfrmance f a plant. In this study exergetic and energetic analysis f Thermal Pwer Statin Muzaffargarh in Pakistan is carried ut with an bjective t explre the sites having highest exergetic and energetic lsses in the system. mpnent wise mdelling is used t estimate the perfrmance f the plant by incrprating the effects f varying envirnmental cnditins. It has been fund that highest energetic lsses happened in the cndenser system where 295 MW was lst in the atmsphere. The percent rati f irreversibility t the ttal irreversibility f the biler system was 84 % and 9 % f the cndenser system. The system energetic efficiency calculated n the basis f the fuel lwer heating value was 4%, and exergetic efficiency f pwer cycle was %. In additin, a parametric analysis f the plant perfrmance by varying parameters at the inlet f turbine sectin has als been presented. Keywrds-Energetic Analysis, Exergetic Analysis, Efficiency, Dead State, Thermal Pwer Plant I. INTRODUTION The develpment in the cuntries and living standard f the cmmunities are indicated by energy cnsumptin within it. Rise in energy cnsumptin is resulted due t multiple factrs like: tremendus increase in ppulatin, shifts twards urbanizatin, technlgical prgress and industrial revlutin. Pakistan is a develping cuntry and is facing an unprecedented energy crisis since last few years, which has resulted a supply demand gap f up t 4,5-5,5 MW [i]. The energy mix f Pakistan cmprises abut 88% fssil fuels,.6 % hydrpwer and.7 % nuclear accrding t water and pwer ministry [ii]. These fssil fuel fired thermal pwer plants are playing a key rle in the scenari f Pakistan electricity generatin. Therefre, it is essential that these pwer generatin units wrk at ptimum cnditins fr fuel efficiency. First law f thermdynamics was the initial criteria f a pwer plant's perfrmance evaluatin, hwever the first law has sme inherent limitatins and it is mre apprpriate t use the thermdynamics secnd law as the basis f investigatin. Based upn the secnd law exergetic analysis has becme a mdern tl used t analyze, design, evaluate and t ptimize the pwer plant efficiency. Hasan et al. [iv] presented wrk n cal fired thermal pwer plants and gave detail f thermdynamic inefficiencies and cmparisn f ne plant t the ther. Aljundi [v] presented wrk n steam pwer plant in Jrdan by analyzing all the pwer plant sites separately. Datta et al. [vi] has divided the entire cycle f thermal pwer statin int three znes and presented the exergetic analysis f the pwer plant. Zubair and Habib [vii] presented an exergetic analysis based study n a Rankine cycle with regeneratin and reheating. Naterer et al. [viii] measured lsses in turbine and biler f a cal fueled thermal pwer plant. Ganapathy et al. [ix] presented available and actual energy lsses in a lignite fueled thermal pwer plant. Rsen and Dincer [x] determined the effects f changing the dead state cnditins fr exergetic and energetic study f a thermal pwer plant. Khaliq and Kaushik [xi] analyzed the reheat Barytn and Rankine cmbined pwer cycle and present analysis n the basis f the thermdynamics secnd law. Kurkiya and haudhary [xii] presented an energetic investigatin f a steam pwer plant by calculating energy lsses in each cmpnent separately and als gave the ecnmic ptimizatin f a plant by varying the percentage f carbn in cal cntent. Vsugh [xiii] analyzed a thermal pwer plant with its exergy based analysis. In this analysis the irreversibility in the biler and als the exergetic and energetic based efficiencies f the pwer plant cmpnents were determined. Reddy et al. [xiv] 66

2 Technical Jurnal, University f Engineering and Technlgy (UET) Taxila, Pakistan Vl. 22 N. I-27 presented a review f exergetic and energetic based investigatin f gas fueled and cal fueled P plant. II. PLANT DESRIPTION A 5 MW pwer statin lcated in Multan divisin's district Muzaffargarh f Pakistan was used fr analysis in this study. The pwer plant cmprises f six steam turbine units ( 2) MW, (2 2) MW, ( ) MW at % lad. haracteristics f heavy fuel being used in the thermal pwer plant are given in I. Wrking parameters f the pwer plant are listed in II. The schematic diagram f 2 MW unit is shwn in Fig.. This sectin f 2 MW has a feed water heating (FWH) system. This FWH system is executed in tw steps. First ne is lw pressure heating which have fur heaters and the secnd ne is high pressure heating which have three heaters and a deaeratr heat exchanger. TABLE I TPS MUZAFFARGARH FUEL HARATRITIS [iii] Prperty Density at 5 Flash pint Viscsity at 5 Pur pint Misture Sulphur Ash cntent alrific value TABLE II TPS MUZAFFARGARH WORKING PARAMETERS Parameters Unit Kg/m centistkes % V/V % m/m % m/m K al/kg Steam flw rate f mass Ht prducts t the biler flw rate f mass Flue gases temperature Feed water entering temperature t biler Flw rate f steam Temperature f steam Pressure f steam Output pwer ling water flw rate f mass ling water temperature Unit MPa MW Quantity / Quantity III. ANALYSIS The aim f this study is t identify the pwer plant cmpnents which have a critical cntributin twards plant efficiency. The thermal pwer plant is analyzed n the basis f bth exergetic and energetic analysis tgether t get the cmplete interpretatin f system features. Mass, energetic and exergetic balances are cnsidered in the fllwing thermdynamical analysis f the pwer plant. Steady state flw is assumed and changes in bth ptential and kinetic energies are neglected. The general mass balance fr any cntrl vlume f a steady state prcess is written as: () Fr any cntrl vlume, the general energy balance can be written as: (2) Fr any cntrl vlume, the general exergy balance can be written as: () Where X represents the net energy transfer by heat heat at temperature T, can be calculated as: Ttal exergy rate is written as: The energetic efficiency f the pwer plant is: The Exergetic efficiency f the pwer plant is: (4) (5) (6) (7) Steam turbine with steam reheating is used which cmprises f single shaft and three cylinders. Steam is superheated t 54 with a pressure f 2.7 MPa, which is pushed t the turbine sectin. The steam cming ut frm the turbine is then sent t water cled cndenser where the phase change ccurs fr reuse and the cyclic prcess starts. Parametric values f the thermal pwer plant are given in III. 67

3 Technical Jurnal, University f Engineering and Technlgy (UET) Taxila, Pakistan Vl. 22 N. I Biler HPT 2 HPH7 HPH6 HPH5 4 IPT 6 5 LPH4 LPH LPH2 LPT 7 LPH LPT 8 9 LP HP D Fig.. TPS Muzaffargarh 2MW unit layut. IV. RESULT AND DISUSSION Engineering Equatin Slver (EES) sftware was used t calculate the water thermdynamic prperties at designated pints in Fig.. The thermal pwer plant was analyzed by abve relatins with dead state pressure and temperature.5 kpa and 25 respectively. The energetic balance and percent rati f input energy f fuel in the thermal pwer plant cmpnents are presented in IV. It shws that 5.2 % f the ttal fuel energy is lst in the cndenser and discharge in the atmsphere. The percent rati f energy lst in the biler is 28 % f all the lsses [v]. Hwever, energy based analysis can be misleading. TABLE IV ENERGETI BALANE AND PERENT RATIO OF FUEL ENERGY INPUT IN POWER PLANT OMPONENTS Sectin ndenser Biler Heaters Deaeratr Ttal Heat Lss (MW) Percent rati The values f irreversibility and percent rati f irreversibility in the cmpnents are given in V. It.5. shws that biler alne destryed 84 % f available energy in the pwer plant. Energetic analysis shws cndenser t be highest energy destructin site, yet in exergetic analysis the percent rati f irreversibility t the ttal irreversibility in the cndenser is nly 9 %. Based n LHV f fuel exergetic and energetic efficiencies f the Thermal Pwer Statin Muzaffargarh cmes ut % and 4 % respectively [v]. TABLE V IRREVERSIBILITY AND ITS PERENT RATIO OF IRREVERSIBILITY IN TPS MUZAFFARGARH OMPONENTS AT T =25, P =.5 kpa. Sectin Biler ndenser LP pump LPH LPH 2 LPH LPH 4 HP pump HPH 5 HPH 6 HPH 7 Pwer cycle Irreversibility (MW) Percent rati

4 Technical Jurnal, University f Engineering and Technlgy (UET) Taxila, Pakistan Vl. 22 N. I-27 TABLE III PARAMETERI VALUES OF POWER PLANT Pints Mass flw rate () Temperature ( ) Pressure (KPa) Enthalpy (KJ/Kg) Entrpy (KJ/KgK) Fig. 2 shws significant differences between energetic lsses and irreversibility in the main sites f the thermal pwer plant which are biler, cndenser and three cmpunds f the turbine. It can be seen that available energy lsses in the cndenser are quite less than actual energy lsses, indicating the energy d e s t r y e d i n t h e c n d e n s e r s y s t e m w a s thermdynamically unimprtant due t its lw quality. The biler sectin shws the highest irreversibility in the thermal pwer plant cmpnents Biler HP IP LP ndenser Irreversibility (MW) Energetic Lss (MW) Fig. 2. Energetic lsses and irreversibilities in the main sites. Fig. shws generated pwer utput variatin with respect t steam mass flw rate inlet t the turbine. It shws a rise in pwer utput values with the rise in mass flw rate value [viii]. This can be helpful in determining the requirement f steam mass flw rate, accrding t the required pwer prductin when the generatin unit has t perate n part lad cnditins. Generated pwer utput (MW) Pwer Output Mass flw rate f steam (kg/s) Fig.. Effect f mass flw rate n the generated pwer utput. 69

5 Technical Jurnal, University f Engineering and Technlgy (UET) Taxila, Pakistan Vl. 22 N. I-27 Fig. 4 and 5 shw the influence f the steam pressure and temperature n the cyclic perfrmance respectively. It is clear that by increasing the superheated steam parameters efficiency f the system rises [viii]. While keeping same, the steam mass flw rate and fuel input t the biler, we can btain higher pwer utputs by increasing the cycle steam temperature and pressure. Efficiency (%) Efficiency (%) Steam Temperature () Fig. 4. Effect f steam temperatures n efficiencies. 5 4 eta energy eta exergy eta energy eta exergy Steam Pressure (KPa) Fig. 5. Effect f steam pressure n efficiencies. We can quantify exergy f any system by specifying the system and its surrundings. Accrding t energy analysis the thermdynamic prperty is nt effected by changing the dead state, hwever, change in the dead state can affect the exergetic analysis results. T bserve the effectiveness f dead state in the system perfrmance the dead state temperature is varied frm t 5 while maintaining the pressure at.5 kpa. The ttal irreversibility rates f all the thermal pwer plant cmpnents at different dead state temperatures are summarized in VI, whereas irreversibility with respect t varying dead state temperature in three main sites f the thermal pwer plant are shwn in Fig. 6, which shws that the irreversibility rate in the biler and turbine increases and decreases in the cndenser with the increase in a dead state temperature [v]. The result still remains the same that whatever the dead state will be, the biler remains the largest irreversibility site in the pwer plant. Irreversibility (MW) 9 6 Biler ndenser Dead state temperature ( ) Fig. 6. Effect f dead state temperature in main cmpnents f the thermal pwer plant. TABLE VI IRREVERSIBILITY IN ALL OMPONENTS OF POWER PLANT AT DIFFERENT DEAD STATE TEMPERATURE, (MW). Sectin ( ) 5 ( ) 2 ( ) 25 ( ) ( ) 5 ( ) 4 ( ) 45 ( ) 5 ( ) Biler ndenser LP pump LPH LPH LPH LPH HP pump HPH HPH HPH

6 Technical Jurnal, University f Engineering and Technlgy (UET) Taxila, Pakistan Vl. 22 N. I-27 V. ONLUSION In this paper exergetic and energetic analysis f Thermal Pwer Statin at Muzaffargarh in Pakistan has been presented. In this pwer plant cndenser shwed the highest energetic lsses where almst half f the fuel energy input t system was lst in the envirnment. Whereas in exergetic analysis the percent rati f irreversibility t the ttal irreversibility in the cndenser was nly 9% indicating the energetic lss in the cndenser was thermdynamically unimprtant due t its lw quality. Exergetic analysis shwed biler t be the highest irreversibility site where the percent rati f irreversibility t the ttal irreversibility was 84%. The energteic efficiency f the system calculated n the basis f the fuel LHV was 4 % and exergetic efficiency f the thermal pwer cycle was fund t be %. A parametric analysis f the thermal pwer plant, n the basis f varying the parameters like mass flw rate, pressure and temperature f steam at the inlet f turbine has been presented. It is bserved that by increasing superheated steam parameters system efficiency increases. Despite the effectiveness f the dead state temperature n irreversibility in each site f the pwer plant yet the biler remains the key site f irreversibility in the system, which demand directed effrts t enhance the biler sectin perfrmance. AKNOWLEDGEMENT The authrs acknwledge the Thermal Pwer Statin Muzaffargarh, Pakistan fr prviding the plant data fr this study. [i] [ii] [iii] [iv] [v] [vi] REFERENES Pakistan pwer plicy (2). Available frm: HDIP, (Hydrcarbn Develpment Institute f Pakistan), Pakistan Energy Yearbk, Ministry f Petrleum and Natural Resurces, Gvernment f Pakistan, 2. TPS Muzaffargarh, RFO specificatin, ISO 827:22. H. H. Erdem, A. V. Akkaya, B. etin, A. Dagdas, S. H. Sevilgen, B. Sahin, et al., "mparative energetic and exergetic perfrmance analyses fr cal-fired thermal pwer plants in Turkey," Internatinal Jurnal f Thermal Sciences, vl.48, pp , // 29. H. Aljundi, "Energy and exergy analysis f a steam pwer plant in Jrdan," Applied Thermal Engineering, vl. 29, pp. 4-8, 2// 29. S. Sengupta, A. Datta, and S. Duttagupta, "Exergy analysis f a cal-based 2 MW thermal pwer plant," Internatinal Jurnal f Energy Research, vl., pp. 4-28, 27. [vii] M. A. Habib and S. M. Zubair, "Secnd-lawbased thermdynamic analysis f regenerativereheat Rankine-cycle pwer plants," Energy, vl. 7, pp. 295-, 992// 992. [viii] P. Regulagadda, I. Dincer, and G. F. Naterer, "Exergy analysis f a thermal pwer plant with measured biler and turbine lsses," Applied Thermal Engineering, vl., pp , 6// 2. [ix] T. Ganapathy, N. Alagumurthi, R. P. Gakkhar RP and K. Murugesan, "Exergy analysis f perating lignite fired thermal pwer plant, " Jurnal f Engineering Sciences and Technlgy Review,vl. 2, pp. 2-, //29. [x] M. A. Rsen and I. Dincer, "On exergy and envirnmental impact," Internatinal Jurnal f Energy Research, vl. 2, pp , 997. [xi] A. Khaliq and S. Kaushik, "Secnd-law based thermdynamic analysis f Braytn/Rankine cmbined pwer cycle with reheat," Applied Energy, vl. 78, pp , 24. [xii] R. Kurkiya, S. handhary, "Energy analysis f thermal pwer plant," Internatinal Jurnal f Scientific & Engineering Research, vl. 7, pp.- 7, 22. [xiii] A. Vsugh, "Imprving steam pwer plant efficiency thrugh exergy analysis: Ambient temperature," Internatinal nference n Mechanical, Prductin an Autmbile Engineering Singapre, vl. 4, pp , 22. [xiv] S. Kaushik, V. S. Reddy, and S. Tyagi, "Energy and exergy analyses f thermal pwer plants: A review," Renewable and Sustainable Energy Reviews, vl. 5, pp , 2. NOMENLATURE h - Specific enthalpy (KJ/Kg) s - Specific entrpy (J/KgK) m - Mass flw rate () P - Pressure (Pa) I - Exergy destructin rate (W) Q - Heat transfer t steam (W) T - Temperature (K) W - Wrk rate r pwer dne by the system (W) X - Ttal exergy rate (W) LHV- Lwer heating value Greek symbls ex,pp - Exergy efficiency - Specific exergy - Exergy factr Subscripts e - Exit i - Inlet s - Isentrpic - Dead state cnditin f - Fuel p Heat prducts g - Flue gas 7

Investigating The Performance of A Steam Power Plant

Investigating The Performance of A Steam Power Plant Internatinal OPEN ACCESS Jurnal Of Mdern Engineering Research (IJMER) Investigating The Perfrmance f A Steam Pwer Plant * Ahmed Rashad 1, A. Elmaihy *2 1 Department f Mechanical Pwer and Energy, Military