Sulfur conversions during coal char gasification with a two-stage air supply in a pilot-scale circulating fluidized bed gasifier

This paper aims at studying sulfur conversions in a pilot-scale circulating fluidized bed (CFB) gasification system of two-stage air supply. The effects of different air supply approaches, secondary air supply heights and gasification agent compositions on gasifier temperature, sulfur conversions and the release of hydrogen sulfide (H2S) and carbonyl sulfide (COS) were investigated. Two-stage air supply approaches optimized CFB gasifier temperature profile and enhanced sulfur conversions to gas. Sulfur conversions to gas decreased with the increase of secondary air supply nozzle location height. The increased steam-to-carbon ratio promoted sulfur release, leading to more H2S and less COS release.