Sewage sludge char catalyzed steam reforming of volatiles from MSW pyrolysis for H2-rich syngas production: Influence of char properties

Abstract

This study employed a pyrolysis-steam reforming reaction system to produce H₂-rich syngas from municipal solid waste (MSW) with sewage sludge chars (SSCs) as catalysts. To determine the most important SSC properties influencing H₂ yield, catalytic performances of 7 different plain SSCs were compared to choose the proper SSC as catalyst. The pyrolysis of MSW and steam reforming of the volatiles were carried out at 550 and 800 °C respectively, and H₂ production from different MSW components were also checked. It has been found that the fixed carbon (FC) content of SSCs is the most important factor influencing H₂ yield, followed by Fe content and specific area. An FC-Fe-S index was defined to correlate SSC properties with H₂ yield, which exhibits a strong positive correlation (R² = 0.96). Additionally, it has been found the plastics in MSW produce the most long-chain aliphatic volatile compounds during pyrolysis process and result in the highest H₂ yield of 1.54 Nm³/kg_waste in the reforming stage; while biomass components correspond to lower H₂ yields ranging from 0.71 to 0.84 Nm³/kg_waste due to their higher oxygen contents. This research provides valuable insights for choosing cheap SSCs as sacrificial catalyst to enhance H₂ production through MSW pyrolysis-steam reforming technology.