Assessment of oxy-fuel, pre- and post-combustion-based carbon capture for future IGCC plants

Environmental damage due to the emission of greenhouse gases from conventional coal-based power plants is a growing concern. Various carbon capture strategies to minimize CO2 emissions are currently being investigated. Unfortunately, the efficiency drop due to de-carbonization is still significant and the capture rate is limited. Therefore three future hard coal IGCC concepts are assessed here, applying emerging technologies and various carbon capture approaches.The advanced pre-combustion capture concept is based on hot gas clean-up, membrane-enhanced CO conversion and direct CO2 condensation. The concept reached a net efficiency of 45.1% (LHV), representing an improvement of 6.46% compared to the conventional IGCC base case. The second IGCC concept, based on post-combustion capture via calcination–carbonation loops, hot gas clean-up and oxygen membranes, showed a net efficiency of 45.87% (LHV). The third IGCC concept applies hot gas clean-up and combustion of the unconverted fuel gas using pure oxygen. The oxygen is supplied by an integrated oxygen membrane. The combination of IGCC and oxy-fuel process reached a net efficiency of 45.74% (LHV). In addition to their increased efficiency, all of the concepts showed significantly improved carbon capture rates up to 99%, resulting in virtually carbon-free fossil power plants.

► Hot gas cleanup is a highly favorable technology for all selected IGCC concepts.
► Proposed high pressure IGCC with membrane reactor enables direct CO2 condensation.
► IGCC with OTM and carbonate looping enable significant synergy effects.
► Combining IGCC and oxy-fuel is technically challenging but energetically favorable.
► All selected IGCC concepts are able to realize CO2 capture rates up to 99%.