Effects of the ratio of O2/C and H2O/C on sulfur release behaviors during fluidized bed gasification

Gaseous sulfur released during fluidized bed coal gasification will bring lots of negative effects, control the release of gaseous sulfur or the conversion to inorganic sulfur at source is necessary. In this study, sulfur release behaviors of a middle-sulfur coal called Guizhou coal were quantitatively determined through controlled experiments in a lab-scale fluidized bed during oxygen rich-steam gasification. The effects of the molar ratio of O-2/C and the molar ratio of H2O/C on the sulfur release behaviors and the desulfurization performance of limestone were investigated. H2S is the dominate gaseous sulfur. With the molar ratio of O-2/C increases, the yield of four kinds of gaseous sulfur increases, the trend of H2S/COS with O-2/C is not the same as that of H-2/CO, and the yield of H-2 is the main influence factor of the variation of H2S/COS. With the molar ratio of H2O/C increases, the yield and concentration of four kinds of gaseous sulfur increases, and the molar ratio of H2S/COS and H-2/CO increase. The addition of limestone does not change the trend of gaseous sulfur with O-2/C or H2O/C. The reduction rate of gaseous sulfur decreases with the increase of O-2/C, but with the increase of H2O/C, the reduction rate of gaseous sulfur increases first and then decreases. Increasing the ratios of O-2/C and H2O/C simultaneously is not conducive for the conversion to H2S and the sulfuration of limestone.

Automated summary

In this study, the sulfur release behaviors of Guizhou coal during fluidized bed coal gasification were quantitatively determined, and the effects of O2/coal and H2O/coal ratios on sulfur release behaviors were investigated. The results showed that the yield of gaseous sulfur is influenced by the ratios of oxygen and steam.