Maximizing coal-fired power plant efficiency with integration of amine-based CO2 capture in greenfield and retrofit scenarios

A modeling study was performed to investigate the direct impact of amine CO2 scrubbing on the efficiency of a coal-fired power plant. The full scope of the capture process was simulated with 8 m PZ (piperazine) to estimate the steam, electricity, and cooling water requirements. The steam cycle was simulated for applications of the capture technology to both retrofit and greenfield (optimized new build) coal-fired power plants. The reboiler duty of the stripping column had an optimal molar L/G (liquid to gas ratio) of 4.9 in the absorber and the maximum reboiler temperature of 150 °C. Integration of this CO2 capture with a greenfield coal plant yielded an identical optimal L/G, but the optimal reboiler temperature was 140 °C, and the decrease in power plant efficiency was 7.3%. The retrofit case resulted in an optimum case with an L/G of 5.9, a reboiler temperature of 120 °C, and a decrease in plant efficiency of 7.0%. When running at the optimal L/G, the optimization sensitivity to the reboiler temperature was low.