Process design and economic analysis of membrane-integrated absorption processes for CO2 capture

Abstract

This study proposes a design and optimization framework for a membrane-integrated absorption CO2 capture process for a coal-fired power plant. A modeling framework was developed for the hybrid capture process. The design was made by considering different flow-rate distributions between the combustion and sweep air for the membrane, as well as series and parallel configurations in an integrated manner. Sensitivity analysis was performed to understand the impact of the ratio of the combustion air being fed to the membrane on the capture performance and its economics under a hybrid configuration. As a case study, a coal-fired power plant was selected to implement the membrane-integrated absorption CO2 capture process, which was simulated with Unisim (R) and MATLAB (R). A techno-economic assessment was used to understand the capital investment and operating expenditure related to the capture process. Compared to a stand-alone absorption process, 4.73% energy savings could be identified with a hybrid series configuration, whereas the parallel configuration offered 6.11% savings in capital cost from the reduction in equipment size. Although economic benefits can be obtained from hybrid processes through the development of membrane performance, the hybrid processes considered in this work are marginally more expensive than a stand-alone absorption process.