Exergy analysis of a 420 MW combined cycle power plant

• Published in: International journal of energy research Vol. 32; no. 2; pp. 175 - 183
• Main Authors: Ameri, M., Ahmadi, P., Khanmohammadi, S.
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01.02.2008; Wiley
• Subjects: Applied sciences; combined cycle power plant; efficiency; Energy; Energy. Thermal use of fuels; Engines and turbines; Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc; Exact sciences and technology; exergy; heat recovery steam generator; Heat transfer; Theoretical studies. Data and constants. Metering; efficiency; Power production; Optimization; Steam generator; heat recovery steam generator; Combustion chamber; Combined cycle; Combustion gas; Exergy analysis; Combined cycle power plant; Waste heat boiler; Burner; Exergy; Gas turbine; Heat transfer
• ISSN: 0363-907X; 1099-114X
• DOI: 10.1002/er.1351

Combined cycle power plants (CCPPs) have an important role in power generation. The objective of this paper is to evaluate irreversibility of each part of Neka CCPP using the exergy analysis. The results show that the combustion chamber, gas turbine, duct burner and heat recovery steam generator (HRSG) are the main sources of irreversibility representing more than 83% of the overall exergy losses. The results show that the greatest exergy loss in the gas turbine occurs in the combustion chamber due to its high irreversibility. As the second major exergy loss is in HRSG, the optimization of HRSG has an important role in reducing the exergy loss of total combined cycle. In this case, LP‐SH has the worst heat transfer process. The first law efficiency and the exergy efficiency of CCPP are calculated. Thermal and exergy efficiencies of Neka CCPP are 47 and 45.5% without duct burner, respectively. The results show that if the duct burner is added to HRSG, these efficiencies are reduced to 46 and 44%. Nevertheless, the results show that the CCPP output power increases by 7.38% when the duct burner is used. Copyright © 2007 John Wiley & Sons, Ltd.