Experimental Study of Gaseous Sulfur Species Formation during the Steam Hydrogasification of Coal

Steam hydrogasification is the thermochemical conversion of carbonaceous materials into synthesis gas in a steam- and hydrogen-rich environment. The formation of gas-phase sulfur species during the pyrolysis and gasification of sulfur-containing feedstocks, such as coal, presents well-known challenges. Gas-phase sulfur component formation under typical steam hydrogasification conditions was studied experimentally, and the impact of process parameters has been evaluated. The experimental results show that sulfur in the feedstock is mainly converted to hydrogen sulfide (H2S) during the steam hydrogasification reaction (SHR) process. Carbonyl sulfide (COS) and carbon disulfide (CS2) were not observed in the gas phase. The H-2- and steam-rich environment in the SHR process is favorable for the formation of H2S and suppresses COS and CS2 formation. The H2S concentration in the gas phase increased consistently with increasing temperatures (700-800 degrees C) and increasing water/coal mass ratios (0.5-3). These results are important in the development of a downstream sulfur cleanup system during SHR-based coal conversion.