Catalytic plastics cracking for recovery of gasoline-range hydrocarbons from municipal plastic wastes

This paper reviews recent developments in plastics cracking, a process developed to recycle plastic wastes into useful petrochemical materials. Under thermal cracking conditions, plastic wastes can be decomposed into three fractions: gas, liquid and solid residue. The liquid products are usually composed of higher boiling point hydrocarbons. By adopting customary fluid cracking catalysts and reforming catalysts, more aromatics and naphthenes in the C6–C8 range can be produced, which are valuable gasoline-range hydrocarbons. More tests are, however, needed to verify the pyrolysis process in a pilot scale particularly for treatment of mixtures of bulk plastics. Plastics cracking is only an elementary conversion technology; its application has to be combined with other technologies such as municipal solid waste collection, classification and pretreatment at the front end, as well as hydrocarbon distillation and purification at the back end. Social, environmental and economic factors are also important in industrial implementation of the technology.