Hydrocarbons recovery through catalytic pyrolysis of compostable and recyclable waste plastics using a novel desk-top staged reactor

The overall objective of this study is to develop a novel two-staged fixed-bed reactor to evaluate the catalytic pyrolysis of recyclable (HDPE) and compostable waste plastics and to enhance the selectivity of gasoline range hydrocarbons in pyrolysis liquid. In this research, both used and unused compostable bioplastics, recyclable high-density polyethylene (HDPE) grocery bags, and unused HDPE were used as a feedstock Additionally, a mixture of recyclable plastic and compostable bioplastic with 1:1 ratio was pyrolyzed at 500 °C, and the pyrolysis oil products were compared with commercial gasoline. Zeolite Socony Mobil-5 (ZSM-5) was used as a catalyst in all the catalytic pyrolysis experiments, which produced wax-free shorter chain hydrocarbons similar to commercial gasoline. The addition of recyclable HDPE in compostable plastics improved the selectivity of gasoline range hydrocarbon (C₆−C₁₂) by 10% and increased the calorific value of pyrolysis liquids by 7.5% (43 MJ/kg), which is equivalent to commercial gasoline. Moreover, both compostable and recyclable plastics produced aromatic and aliphatic hydrocarbons that have potential applications in lubricants, additives, and petrochemical industries.