CO2 capture for PC-boilers using oxy-fuels—A transition strategy

Publisher Summary This chapter discusses the fundamental concept that involves replacing combustion air with oxygen diluted by recirculated CO 2 from the flue gas. This eliminates N 2 -CO 2 separation, permitting more economical CO 2 recovery than competing amine systems. A CO 2 /O 2 molar ratio of ∼3 is necessary to preserve the heat-transfer performance and gas-path temperatures. In a site specific study retrofitting a low-sulfur coal-fed boiler, CO 2 recycle shows competitive, operating, and environmental release advantages when compared to amine scrubbing systems. Anticipated breakthroughs in O 2 production will further improve the advantages. For oxy-fuels high-sulfur operation using flue gas desulfurization (FGD) should be practical, and in a related experimental study, it is found that high CO 2 partial pressures from oxy-fuels have a negligible impact on SO 2 -reagent use although FGD solids handling will require redesign. One of the special opportunities afforded by CO 2 /O 2 recycle is that it should prove very attractive at sites considering repowering and converting to an integrated-gasification-combined-cycle (IGCC) to produce H 2 and electricity.