Effectiveness of membranes and hybrid membrane processes in comparison with absorption using amines for post-combustion CO₂ capture

The effectiveness of membrane processes and feasibility of hybrid processes combining membrane permeation and conventional amine absorption processes were investigated for post-combustion CO₂ capture. The traditional MEA process uses a substantial amount of thermal energy at the stripper reboiler when CO₂ concentration increases. Questions are sometimes raised if the membranes can compete with amine absorption for post-combustion CO₂ capture. Although both processes have their own advantages, can a hybrid process for post-combustion CO₂ capture be yielded combining membranes and amine absorption with cost/performance advantages? Several single stage and multi-stage membrane process configurations were simulated for a target capture requirement aiming at possible application in enhanced oil recovery. It was shown that membrane processes offer the lowest energy penalty for post-combustion CO₂ capture and are likely to expand as more and more CO₂ selective membranes are developed. A comparison of energy perspective for the CO₂ capture processes studied was drawn, and it was shown that the energy requirements of the hybrid processes are less than conventional MEA processes. The total energy penalty of the hybrid processes decreases as more share of CO₂ is removed by the membranes.