The effect of Kankara zeolite-Y-based catalyst on some physical properties of liquid fuel from mixed waste plastics (MWPs) pyrolysis

Abstract

The effect of Kankara zeolite-Y-based catalyst on some physical properties of liquid fuel obtained from the pyrolysis of mixed waste plastics has been investigated. Combination of zeolite-Y, metakaolin, aluminum hydroxide and sodium silicate all synthesized from Kankara kaolin from Kankara in Katsina State, Nigeria, was used as catalysts. In this study, fifteen experiments were conducted: fourteen set of 200 g of the mixed waste plastics comprising 27 wt% HDPE, 33 wt% LDPE, 13 wt% PP, 18 wt% PS, 9 wt% PET were de-polymerized with catalyst and a set without catalyst (thermal pyrolysis) in a batch reactor. The maximum temperatures for catalyzed and thermal pyrolysis in this study are 350 °C and 490 °C, respectively. The catalyst components were characterized by XRF analysis, while their textural properties were determined from BET technique by N2 adsorption at − 196 °C. A constant catalyst-to-plastic ratio of 1:10 was used for all the catalyzed reactions. The catalyzed liquid sample with the optimum yield of 46.7 wt% was obtained using 10.49 wt%, 32.42 wt%, 27.09 wt% and 30 wt%, of zeolite-Y, metakaolin, aluminumhydroxide and sodium silicate, respectively, while the thermal pyrolysis gave a liquid yield of 66.9 wt%. Furthermore, the liquid products obtained for both thermal and catalytic cracking at optimum yield were characterized for their suitability as fuel. The properties determined were density, viscosity, fire point, and calorific value. The results suggest that catalytic pyrolysis produced liquid products whose properties are comparable to conventional fuels (gasoline and diesel oil) and more suitable for use as liquid fuel than that produced through thermal pyrolysis.