Catalytic Gasification of Sewage Sludge in Supercritical Water: Influence of K₂CO₃ and H₂O₂ on Hydrogen Production and Phosphorus Yield

Abstract

In this work, the catalytic gasification of sewage sludge in supercritical water was investigated in a batch reactor (460 °C, 27 MPa, 6 min), and the separate and combined effects of the catalyst on the H₂ production and phosphorus yield were investigated. The experimental results indicated that K₂CO₃ alone improved the H₂ yield, gasification efficiency (GE), and carbon gasification efficiency (CE). The largest H₂ yield of 54.28 mol/kg was achieved, which was approximately three times that without a catalyst. Furthermore, the inorganic phosphorus (IP) yield increased with the addition of K₂CO₃. However, when H₂O₂ was added, the H₂ yield quickly decreased with increasing H₂O₂ coefficient, and more than 97.8% of organic phosphorus (OP) was converted into IP. The H₂ yield increased with the addition of various K₂CO₃/H₂O₂ ratios, whereas the IP yield decreased.