(195d) Oxycoal Combustion: Opportunities and Challenges - Purification of Oxyfuel-Derived CO2

Two key aspects of oxycoal combustion in power boilers are the process concepts for the oxy-combustion within the boiler scope and the backend CO2 purification and compression. Thoughtful integration of various unit operations can improve the overall efficiency of the oxycoal combustion process for power production. As for the CO2 capture process, special attention must be paid to the contaminants within the raw CO2 product beyond the typical H2O, O2, N2, and Ar. In particular, acid gases such as SO3, SO2, HCl and NOX produced as products of combustion represent both an opportunity and a challenge. These acidic impurities will need to be removed from the CO2 stream before it is introduced into the pipeline to prevent corrosion and comply with possible regulations. In this paper we review the latest process concepts/integration for oxycoal combustion for CO2 capture as well as an integrated process for CO2 compression and simultaneous purification to produce CO2 product streams at purities up to essentially pure CO2.