Effects of Process Parameters on Sulfur Migration and H2S Generation during Supercritical Water Gasification of Sludge

On the selective desulphurization of biomass derivatives in supercritical water

“…Hydrogen sulphide was detected in the three HTL waters exposed to HTG conditions. The slight increase in H 2 S concentration probably originates from the decomposition of organosulphur compounds (see equations 1 and 2) [31], but also possibly by the ex situ reaction of trisulphides with water (see reverse equation 4) [39]. Overall, it can be observed that HTL process waters produced from Miscanthus and sewage sludge did not experience dramatic changes after being exposed to HTG conditions.…”

“…However, little is known about the nature of organosulphur compounds formed during the reductive hydrothermal treatment of biomass. Recent work identified several organosulphur compounds in the biogas produced during the hydrothermal treatment of sewage sludge [31]. Along with H 2 S, the concentration of methanethiol, ethanethiol, dimethyl sulphide and dimethyl disulphide were found to increase with the temperature rising from 633 to 713 K. The characterization of the compounds present in the liquid phase indicates the presence of some thiophenes and thiols, but the identification of several compounds remains to be confirmed.…”