Catalytic Pyrolysis of Polyethylene and Polypropylene Over Y Zeolite

Polyethylene (PE) and polypropylene (PP) are typical plastic waste. At present, there are mainly four methods of treatment: landfill, incineration, recycling, and thermal pyrolysis. Compared with thermal cracking, the advantages of catalytic cracking are mainly reflected in lower reaction temperature, faster reaction rate, and higher yield of pyrolysis target products. In this study, HDPE/PP was catalyzed by three kinds of catalysts. The high-temperature treatment and acid-alkali leaching were used to change textural properties and acid sites attribution of zeolite. It was found that the acidity density affected the gas and liquid yield, but the existing form of coke deposits changed due to the difference in adsorption. Besides, the pore structure has an obvious effect on acidity retention and catalytic cycling stability. Compared with pore structure, the distribution of acidity obviously has a larger impact on the distribution of product yield.