Hydrogen-rich syngas production from sewage sludge and hydrochars via catalytic gasification with SrO

This study investigates the production of high-quality syngas from sewage sludge and its hydrochars through gasification and catalytic gasification processes. The following types of sludge were analyzed: digested (MS1) and non-digested (MS2) municipal sludge from Silesian wastewater treatment plants (WWTPs) and two industrial sludge hydrochars (HC_IS1, HC_IS2). Hydrochars (HC_MS1, HC_MS2, HC_IS1, HC_IS2) were derived via hydrothermal carbonization at 200 °C and 2 h. Gasification and catalytic gasification processes with SrO were conducted under a CO 2 atmosphere at 850 °C. Gas chromatography was employed to identify syngas components, including H 2 , CH 4 , CO 2 , and CO. The results demonstrated that the presence of a catalyst significantly increased hydrogen (H 2 ) yield, particularly during the heating stage. For instance, hydrogen increased from 4 % to 21.7 % for HC_MS1, although with HC_MS2 no hydrogen was found until the addition of a catalyst, SrO, which increased hydrogen to 7.6 %. The findings confirm the potential of gasification for syngas production from sewage sludge and hydrochars. • Hydrochar is potential feedstock for hydrogen production via gasification. • H 2 -rich syngas is produced from sewage sludge and hydrochars via gasification. • Catalytic gasification with SrO in CO 2 atmosphere at 850 °C boosted H 2 yield. • Presence of SrO significantly increased H 2 yield.