Study on the Mechanism and Energy Consumption of CO2 Regeneration Process by Membrane Electrolysis

A significant barrier for carbon capture and sequestration (CCS) deployment is the high capital cost and the high energy consumption for capturing CO2 from a coal fired power station. Novel membrane electrolytic regeneration technology has been reported to significantly reduce the energy consumption compared with the conventional thermal regeneration process [Martin, F. J.; Kubic Jr., W. L. Green Freedom: A Concept for Producing Carbon-Neutral Synthetic Fuels and Chemicals; LA-UR-07-7897; Los Alamos National Laboratory, Los Alamos, NM, USA, 2007]. The mechanism and energy consumption for this novel process have been studied in this paper. CO2 regeneration was achieved through the membrane electrolysis process, and CO2 regeneration efficiency reached as high as 100%. At room temperature, the membrane electrolysis process is considered in three stages: no CO2 release stage, enhanced CO2 release stage, and steady CO2 release stage. The mechanisms for each stage and the whole process have been presented. Compared with the traditional CCS process, the energy requirement is significantly reduced to 16.6% for the regeneration process and 25.8% for the total CO2 capture and compression process using the electrolysis regeneration process based on ASPEN PLUS simulations. Further work on the membrane electrolytic regeneration is needed to examine the impact of promoters, the optimization of electrolysis conditions, and the equipment cost.