Pyrolysis of plastic waste into green fuels – experimental study

Abstract

Recycling of plastic waste in more environmental friendly ways is under great attention. Catalytic pyrolysis of plastic waste is among the sustainable methods that can recover valuable products from plastics. However, this method faces challenges due to complex nature of plastics and complex catalytic kinetics. Therefore, this experimental work aimed at utilization of an improved semi-batch reactor to evaluate recovery of valuable products from LDPE through catalytic pyrolysis over ZSM-5 catalyst. Experimental design employed to evaluate the improved set-up and yield of resulted gases and liquids at different catalyst loadings and temperature. TGA used to simulate polymer degradation in presence and absence of catalyst and catalyst screening. The obtained product further analyzed by gas chromotgraphy and FTIR to identify different groups of hydrocarbons in products. Thermal pyrolysis resulted mostly waxes that contained heavy olefinic C20+. Addition of ZSM-5 significantly improved the gas yield which was containing noticeable amount of olefin monomers (ethylene and propylene). On the other hand, ZSM-5 upgraded the liquid product to gasoline ranged fuel (C5-C12) rich in aromatic. Both increasing temperature and increasing ratio of catalyst was associated with production of light gases. At the same time effect of catalyst loading was more sensible at lower temperature. However, utilization of semi-batch reactor is not a good option as there is no proper control on residence time of products, and therefore, less contact between reactant and catalyst resulted.