Energetic evaluation of different flow sheet modifications of post-combustion CO₂ capture plant at coal and natural gas fired power plant for a generic improved solvent

The post-combustion capture (PCC) technology is a promising possibility to reduce CO₂ emissions of fossil fuel fired power plants. One of the main concerns for the PCC is the loss in electric power output. A reduction in efficiency penalty for solvent based PCC can be achieved by improving the solvent properties as well as by improving the process design. There are many different process flow sheet modifications with an improvement in process design reported in literature. In this work two of these modifications for a capture plant are evaluated. To be able to compare these process modifications it is necessary to evaluate them on identical solvent and process conditions. The modified processes are compared to base cases processing the flue gas from a supercritical pulverised coal fired power plant as well as a natural gas combined cycle power plant. The solvent used in the capture plant is a generic improved solvent, representing possible future solvents. The main advantages of the flow sheet modifications are pointed out. Subsequent, the specific reboiler heat duty, the specific cooling duty and the specific auxiliary power for the capture plant are shown for the flow sheet modifications. The overall efficiency penalties for the flow sheet modifications are compared and differences are highlighted.