Exergy analysis of a 1000 MW single reheat advanced supercritical carbon dioxide coal-fired partial flow power plant

Abstract

A comprehensive energy and exergy analysis for traditional steam power plant (TSPP) and supercritical carbon dioxide (S-CO2) power plants is constructed. The exergy distribution analysis and optimization methods of the Cycle-Internal-Split-Flow (CISF) and Connected-Top-Bottom-Cycle (CTBC) units of the S-CO2 partial flow power plant are conducted. The energy analysis reveals that the S-CO2 power plant (SCO2PP) has the remarkable characteristics of higher average endothermic temperature and overall power plant energy efficiency compared with traditional steam power plant. The results show that the exergy loss of the heat exchange surface of SCO2PP is obviously lower than that of TSPP. And the exergy loss of the heat exchange surface and S-CO2 Brayton cycle has more remarkable effect on the overall power plant exergy efficiency compared with other subsystems. Besides the main findings are the following: the exergy loss of FGC and HTR takes up considerably high percentages in CISF unit and connected-bottom-cycle turbine (CBT) has relatively lower exergy efficiency in CTBC unit. The innovative S-CO2 boiler layouts including adjacent double flue gas cooler (ADFGC) and staggered double flue gas cooler (SDFGC) layouts are presents in the CISF and CTBC units, respectively. From the perspective of system performance and layout complexity, the 1000 MW single reheat S-CO2 partial flow coal-fired power plant using the CISF and the ADFGC boiler layouts offers more interesting advantages: the 48.22% overall plant exergy efficiency (LHV) and simpler system configuration.