Based on a realized coal polygeneration technology, the effects of temperature, char heat carrier (CHC)/coal mass ratio, and CHC production temperature on sulfur transformation during coal pyrolysis with char as heat carrier were evaluated in a fluidized-bed reactor. The sulfur content in three-phase pyrolysis products was determined, including gaseous sulfur and the variation of sulfur forms in the mixed-char.

Abstract

To investigate sulfur transformation during coal pyrolysis with char heat carrier (CHC), the effects of temperature, CHC/coal, and CHC production temperature were explored in a fluidized bed. The yield rates of sulfur in H₂S () and Y _COS elevated with temperature. and Y _char-S decreased, and temperature showed no significant effect on Y _tar-S. CHC inhibited sulfur transformation to the gas phase. More H₂S and COS were fixed in mixed-char in form of CaS by CHC, resulting in the increase of Y _char-S. CHC was favorable for CH₃SH decomposition. The inhibitory effect was enhanced with increasing CHC/coal. Higher production temperature inhibited the sulfur fixation capacity of CHC. CHC enhanced the decomposition of pyrite, organic sulfur, sulfate, and the yield of sulfide in mixed-char.