Integrated two-step co-pyrolysis under several low-cost natural catalysts to produce aromatic-rich liquid fuel from mixed municipal solid waste

Abstract The world’s increasing human population and industrial activities have resulted in an enormous rise in energy consumption throughout the years. Substantial attention has been given to the impending energy crisis caused by the depletion of fossil fuel supplies and their contribution to environmental degradation. As a result, it is necessary to investigate and make use of nonfossil energy sources for the purpose of maintaining demand stability as well as creating a sustainable green environment. Pyrolysis is a reliable method to convert municipal solid waste materials into useful energy. Hence, the co-pyrolysis of unsegregated municipal solid waste was investigated in this study using an integrated two-step pyrolysis process with a double reactor, supported by various natural catalysts, such as zeolite, dolomite, and kaolin, at 550°C for 210 minutes as constant variables—an approach that has not been reported previously. To determine the physical and chemical properties, liquid fuel was subjected to ASTM and gas chromatography–mass spectroscopy analyses, and the impact of each catalyst on its characteristics was also examined. The aromatic fraction was prominent in the liquid fuel yields produced using kaolin and zeolite catalysts (57.4% and 46.1% peak area, respectively). Meanwhile, the highest yield of liquid fuel was obtained using dolomite as the catalyst. The viscosity and density of liquid fuel with dolomite, kaolin, and zeolite were 10.83, 4.25, and 4.04 mm2/second and 0.88, 0.89, and 1.01 g/cm3, respectively. Conversely, the corresponding calorific values for zeolite, kaolin, and dolomite were 41.37, 41.09, and 41.19 MJ/kg, respectively. The physical characteristics of the liquid fuel are comparable to those of common fuels such as petrol-88, which is utilized in Indonesia as a vehicle fuel.