Catalytic pyrolysis of plastic waste and molecular symmetry effects: a review

The present review addresses the latest findings and limitations in catalytic pyrolysis for the processing of plastic waste into valuable fuels. Compared to thermal degradation of plastics, catalytic pyrolysis provides better results in regards to the quality of the obtained liquid hydrocarbon fuel. Different types of catalysts can be used in order to improve the thermal degradation of plastics. Some of the most used catalysts are different types of zeolites (HUSY, HZSM-5, Hb), Fluid Catalytic Cracking (FCC), silica-alumina catalysts, or natural clays. There is a need to find affordable and effective catalysts in the aim of achieving commercialization of catalytic pyrolysis of plastic waste. Therefore, this study summarizes and presents the most significant results found in the literature in regards to catalytic pyrolysis. This paper also investigates the symmetry effects of molecules on the pyrolysis process.