Work

In-situ tar reduction and catalytic reforming in sewage sludge gasification using steel slag oxygen carrier

Year: 2026

Type: article

Abstract: Tar formation during sewage sludge gasification severely reduces process efficiency and causes operational and environmental problems. In this work, FeO-rich steel slag was employed as a low-cost oxygen carrier to assist sludge gasification, and the transformation behaviour of major tar compounds was systematically investigated. Under optimal conditions, the total tar yield decreased by over 70 %, and syngas production reached about 3.5 m 3 /kg with an H 2 /CO ratio close to 1:1. Besides, sludge-derived aliphatics and oxygenated organics preferentially evolved into phenolic and N -containing tars, whose polar functional groups and conjugated structures were removed by >80 %, accompanied by fluorescence quenching and blue-shift. Theoretical calculation revealed that FeO promotes adsorption (−1.2 to- 2.4 eV) and C C/C H/C N bond cleavage via lattice-oxygen migration and redox pathways, thereby suppressing heavy tar formation and enhancing gas yield. These findings provide molecular-level guidance for in-situ tar control and syngas upgrading in sludge gasification.

Source: Bioresource Technology

DOI: 10.1016/j.biortech.2026.134150