Exergoeconomic analysis of a fluidized bed coal combustion steam power plant

Abstract

In this study, extensive exergoeconomic analysis is performed for a 6.5 MW steam power plant using the data obtained from running system. The role and impact of the each system component on the first and second law efficiencies are analyzed to understand the individual performance of sub-components. Moreover, the quantitative exergy cost balance for each component is considered to point out the exergoeconomic performance. The analysis shows that the largest irreversibility occurs in the fluidized bed coal combustion (FBCC), about 93% of the overall system irreversibility. Furthermore, it is followed by heat recovery steam generator and economizer with 3% and 1%, respectively. In this study, the capital investment cost, operating and maintenance costs and total cost of FBCC steam plant are calculated as 6.30, 5.35, and 11.65 US$ per hour, respectively. The unit exergy cost and fuel exergy cost, which enter the FBCC steam plant, are found as 3.33 US$/GJ and 112.44 US$/h, respectively. The unit exergy cost and exergy cost of the steam which is produced in heat recovery steam generator are calculated as 16.59 US$/GJ and 91.87 US$ per hour, respectively. This study emphasizes the importance of the exergoeconomic analysis based on the results obtained from the exergy analysis.