Catalytic Conversion of Polyethylene and Polypropylene Wastes to Light Olefins

The study investigates catalytic conversion of polyethylene and polypropylene—in the form of 1–5 wt % solutions in vacuum distillate—to light olefins in the presence of a catalyst based on a mixture of zeolites Y and ZSM-5. The effects of reaction conditions and polymer pretreatment methods on the conversion degree and product selectivity are discussed. At 675°C quantitative conversion of the polyolefins was achieved, and the products mainly consisted of C₂–C₄ light olefins. The cracking of the polymer solutions enhanced the yield of light olefins compared to the pure vacuum distillate case, the enhancement reaching up to 9.9 wt %, including 5.2 wt % for propylene.