Abstract




 
   

IJE TRANSACTIONS A: Basics Vol. 31, No. 10 (October 2018) 1789-1795   

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  IMPROVEMENT OF EFFICIENCY OF COAL-FIRED STEAM POWER PLANT BY REDUCING HEAT REJECTION TEMPERATURE AT CONDENSER USING KALINA CYCLE
 
G. Khankari and S. Karmakar
 
( Received: November 16, 2017 – Accepted in Revised Form: August 17, 2018 )
 
 

Abstract    This paper proposes an approach for improving the plant efficiency by reducing the heat rejection temperature of power cycle using Kalina Cycle System 11 (KCS11) which is integrated at the steam condenser of a 500 MWe SubC (subcritical) coal-fired power plant. It is modelled by using power plant simulation software ‘Cycle Tempo’ at different plant operating conditions. Results show that the additional net electric power of 5.14 MWe from KCS11 improves the net energy and exergy efficiencies of the power plant by about 0.302 % point and 0.27 % point, respectively at full load over the stand-alone coal-fired steam power plant. Thereby, the carbon dioxide (CO2) emission is reduced by about 2.02 t/h at full load. Combined plant efficiencies decrease with decrease in evaporator outlet temperature due to decrease in vapour quality of binary mixture at turbine inlet and higher steam turbine back pressure. Levelized Cost of Electricity (LCoE) generation and payback period of the combined cycle power plant are about Rs 1.734 and 4.237 years, respectively and the cost of fuel saving is about Rs 0.685 per kg of coal which is lower than the fuel cost.

 

Keywords    Condenser waste heat; Energy; Exergy; Environment; Kalina Cycle.

 

چکیده   

این مقاله روشی را برای بهبود کارایی نیروگاه با کاهش دمای گرما در چرخه قدرت با استفاده از سیستم چرخه کالین 11 (KCS11) پیشنهاد می‌کند که در یک کندانسور بخار یک نیروگاه با سرعتی معادل 500 مگاواتی زیر کریستال نصب شده است. این مدل با استفاده از نرم‌افزار شبیه‌سازی نیروگاه "Cycle Tempo" در شرایط مختلف نیروگاه طراحی شده است. نتایج نشان می‌دهد که توان مازاد بر برق خالص 14/5 مگاوات از KCS11 انرژی خالص و بهره‌وری اضافی نیروگاه به ترتیب در حدود 302/0 و 270/0% بوده است که راندمان نیروگاه بخار زغال سنگ مستقل را بهبود می‌بخشد. به این ترتیب، انتشار دی اکسید کربن (CO2) در حدود 02/0 تن در ساعت در مصرف سوخت کاهش می‌یابد. کارایی نیروگاه سیکل ترکیبی با کاهش دمای خروجی اواپراتور، به دلیل کاهش کیفیت بخار مخلوط با سوخت باینری در ورودی توربین و فشار عقب توربین بخار بالاتر کاهش می‌یابد. هزینه تولید برق مجاز (LCoE) و دوره بازپرداخت نیروگاه ترکیبی در حدود 734/1 Rs و 237/4 سال است و هزینه سوخت ذخیره شده در هر کیلوگرم زغال سنگ 685/0Rs است که کمتر از هزینه سوخت است.

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