Cracking of Model Tar Species from the Gasification of Municipal Solid Waste Using Commercial and Waste-Derived Catalysts

摘要

The cracking of model tar species from municipal solid waste gasification using dried sewage sludge char (DSS char) and bottom ash catalyst (BAC) was investigated, and the catalytic performance was compared to that of well-studied calcined dolomite, NiO/gamma-Al2O3, and non-catalytic thermal cracking. The effects of the temperature, internal structure, chemical composition, and functional groups on the performance of tar cracking were characterized. The results showed that, when toluene was selected as the model tar species, conversion ratios for all catalysts were over 94% at 950 degrees C. The cracking efficiency was ordered as NiO/gamma-Al2O3 > calcined dolomite > DSS char > BAC > thermal cracking. When the temperature increased from 750 to 850 degrees C, the conversion ratios for DSS char and BAC increased from 68.8 and 40.1% to 81.5 and 63.2%, respectively. H-2 and coke were the major products of toluene cracking, and catalysts promoted the yield of hydrogen. The lower heating value of the product gas followed the same rules of the conversion ratio. Coke deposition from toluene cracking will decrease the Brunauer-Emmett-Teller surface area of the catalysts, inevitably leading to the deactivation.