Environmental assessment of a membrane-based air separation for a coal-fired oxyfuel power plant

CO2 reduction from fossil-fired power plants can be achieved by carbon dioxide capture and storage (CCS). Among different CO2 capture technologies for power plants the oxyfuel power plant concept is a promising option. High temperature ceramic membranes for oxygen production have the potential to reduce the associated efficiency losses significantly compared to conventional air separation using cryogenic techniques. Focus of this paper is the environmental performance of membrane-based oxygen production for oxyfuel power plant technology. Included into the analysis are the production of the perovskite membrane (BSCF=Ba0.5Sr0.5Co0.8Fe0.2O3−δ), the incorporation into a steel module, and the integration of several modules into an oxyfuel power plant. The membrane-based oxygen production is compared to the conventional cryogenic air separation in oxyfuel power plants in an ecological way. The evaluation is performed using life cycle assessment (LCA) methodology from “cradle to grave”. The share in the overall environmental impacts of respective life cycle elements like membrane and module production but also coal supply processes as well as the operation of the oxyfuel power plant are identified. Sensitivity analyses referring to life-time, permeability and housing conditions of the membranes set benchmarks for further membrane development.