Exergy Analysis of a Steam Power Plant with Direct Air-Cooling System in China

In this study, the exergy analysis is introduced to analyze a steam power plant in China. The main objectives of this paper are to analyze the system components separately and to identify and quantify their exergy losses and the site having the largest exergy loss. The performance of the plant will be estimated according to the results of the exergy analysis and the proposals of improving the performance of the plant will be presented. The exergy destruction mainly occurred in the boiler system where 189.95 MW was lost, which is followed by the turbine where 12.82 MW was lost. The percentage ratio of the exergy destruction to the total exergy destruction was found to be maximum in the boiler system (91.6%) followed by the turbine (6.18%). The results indicate that the boiler is the major source of irreversibilities in the power plant, and the key of improving the performance of the plant is to improve the exergy efficiency of the boiler system. Chemical reaction is the most significant source of the exergy destruction in a boiler system which can be reduced by preheating the combustion air and reducing the air-fuel ratio.