Multi-stage membrane processes for CO₂ capture from cement industry

Capture conditions for cement plant flue gas differ substantially from other industrial flue gases due to the high partial pressure of CO₂, presenting an opportunity for polymeric membranes to compete with other capture technologies. In this work, two membrane processes are designed by applying a recently developed graphical methodology to identify promising membrane properties, number of stages and operating points for each stage. The net present values of cost and the CO₂ avoidance costs are compared with an MEA based capture unit when applied to a 0.7 MtCO2/year cement plant. The membrane designs are shown to have a significantly lower investment cost (32.6 M€ vs. 294 M€) and CO₂ avoidance cost (27 €/t vs 55 €/t) than the reference MEA based capture process. The investment cost for turbomachinery and the operating cost for electricity are also shown, in this particular case, to be more important than the membrane investment and replacement costs over the lifetime of the membrane capture plant. The present work underlines the importance of using a cost-based approach to balance the trade-offs in membrane process design