Thermodynamic assessment and optimization of a pressurized fluidized bed oxy-fuel combustion power plant with CO2 capture

In this paper, a 600 MW pressurized fluidized bed oxy-fuel combustion power plant integrated with an air separation unit (ASU) and a CO2 compression and purification unit (CPU) was presented. Pressurization increases the flue gas dew point, and more phase-change heat of moisture is thereby available in the flue gas. In the baseline case of 10 bar, the net power efficiency of the plant was 33.40%. The effect of pressure on the plant performance was important whereas the effect of fluidized bed temperature was marginal. The plant with wet mode flue gas recirculation offered higher net power efficiency than the dry mode. Heat integration of ASU, CPU and acid condenser with the steam cycle was conducted to maximize the power production. The use of heat from the acid condenser increased the net power efficiency by 0.81% point over the baseline case. The heat recovery from ASU boosted the net power efficiency by 2.22% points, while the heat recovery from CPU resulted in the net power efficiency improvement of 0.34% point. In the optimization combining ASU, CPU and acid condenser, the net power efficiency increased to 36.83% (LHV), which was competitive over other oxy-fuel combustion counterparts. (C) 2019 Elsevier Ltd. All rights reserved.