Innovative system configuration analysis and design principle study for different capacity supercritical carbon dioxide coal-fired power plant

Abstract The paper constructs the innovative supercritical carbon dioxide (S-CO2) cycle and boiler coupling thermodynamic model, based on comprehensive system analysis of the S-CO2 cycle, S-CO2 boiler and medium temperature heat recovery. The results reveal that moderate cycle maximum pressure and single reheat cycle configuration show the higher cycle efficiency for S-CO2 cycle with the high boiler pressure drop. High temperature flue gas recirculation mode with large proportion and double rectangular furnace boiler layout can increase the boiler heating surface area and lower the heat duty distribution within S-CO2 boiler, which can eliminate the impact of excessive mass flow and increased average endothermic temperature in the S-CO2 cycle. Besides, the system design method and economic evaluation of S-CO2 coal-fired power plants have been constructed. Single split flow cycle configuration is recommended for the 300 MW S-CO2 power plants. And double split flow cycle configuration is compulsory for 1000 MW power plants, showing 50.13% overall power plant net efficiency and 0.705 CNY/kW·h levelized cost of energy (LCOE) at 620 °C/32 MPa. As for the 600 MW capacity power plants, the former configuration considers the boiler heating exchanger layout simplicity, and the latter configuration increases 0.36% overall power plant net efficiency.