High Quality Oil and H2-rich Gas Production from Municipal Solid Wastes Through Pyrolysis and Catalytic Reforming: Comparison of Differently Modified Waste Char-Based Catalysts

Pyrolysis, a promising method for extracting energy and value-added chemicals from municipal solid waste (MSW), encounters challenges associated with generation of inferior quality oil and low-quality char byproducts. In this context, this study proposed catalytic reforming of pyrolysis volatiles derived from MSW, using MSW char (MSWC) and modified MSWC-based catalysts to produce high-quality oil containing monocyclic aromatic hydrocarbons (MAH), alkanes and alkenes, and H-2-rich gas products. Three groups of modified MSWC-based catalysts are prepared through the activation of MSWC with Na2CO3, Zn(NO3)(2)& sdot;6 H2O and ZnCl2 for the reforming process. Experimental findings reveal that impregnating MSW with ZnCl2, specifically the ZnCl2/C-1:1 char from one-step pyrolysis, exhibits the most favorable catalytic performance, with a 47% selectivity of MAH in oil product, yielding > 25 wt% oil at 450 degrees C and a calorific value of 26.24 MJ/kg. Simultaneously, 44 wt% of MSW is converted into gas products with a 49 v/v% H-2 concentration for ZnCl2/C-1:2 catalyst. The Na2CO3-activated MSWC catalyst corresponds to the highest oil yields and achieves an alkane selectivity of 45.95 area% in the oil product, while Zn(NO3)(2)-activated MSWC catalyst corresponds to the highest oxygen compounds in the oil product, thus with the lowest calorific value of 19.4 MJ/kg. These results highlight that varying catalyst modifications to MSW char can effectively improve the production of distinct oil compounds, with Zn[OH](+) species and higher Lewis-acid content in the catalyst exerting a positive influence on aromatic hydrocarbon production; and Na2CO3 facilitating alkane production. This study thus provides valuable insights for upgrading oil product quality and increasing H-2 concentration in gas products, particularly at lower pyrolysis and reforming temperatures.