Thermodynamic evaluation on the chemical looping co-gasification performances of Cr-containing tannery sludge and waste surgical mask

Clean disposal of Cr-containing tannery sludge (CTS) is a serious environmental issue because the high-content Cr is easily oxidized to toxically hexavalent. To realize the waste to energy, the CTS is used for syngas production via chemical looping co-gasification (CLCG) co-feeding with the waste surgical mask (WSM). The thermodynamic analysis is adopted to analyze the syngas’ quality, the chromium’s fate, and the N-, Cl-, and S-containing gaseous products under different gasification temperatures. Then, the effects of the mass flowrates of the steam, OC, and blending ratio of CTS in the feedstock are investigated. It is found that Cr in CTS can maintain trivalent chromium in the CLCG which is beneficial to the environment. Increasing gasification temperature can increase the Q_m from 11.44 to 13.43 MJ/kg. More steam in the gasification agent enhances the H₂ production and H₂/CO ratio in CLCG while increasing OC circulation rate leads to the gasification towards combustion.