Comparison of CO2 separation options for geo-sequestration: are membranes competitive?

Abstract The sequestration of CO 2 as a greenhouse mitigation option is becoming an increasingly important priority for industry. Theoretically membrane based CO 2 removal systems have the potential to provide a cost effective, low maintenance approach for removing CO 2 from gas streams. This study examines the effect of membrane characteristics, operating parameters and system design on sequestration costs for any source-sink combination. The total sequestration cost per tonne of CO 2 avoided for separation, transport and storage are compared for the separation of CO 2 from a black coalfired power plant in Australia. The results show that the membranes currently available have a total sequestration cost of US$55-61/tonne CO 2 avoided. Lower costs for CO 2 avoided can be achieved using an MEA amine based absorption separation system. Gas separation membranes would require significant improvements in CO 2 permeability and selectivity, together with reductions in the cost of membranes and changes to the process configurations and operating pressures to be competitive against MEA systems for the purposes of geo-sequestration.