Thermocatalytic Upgrading of Polymer Waste to Hydrocarbon Fuel Fractions over Mo- and W-Modified Natural Taizhuzgen Zeolite

Plastic recycling, also known as chemical recycling, is widely promoted worldwide as a sustainable way to reduce polymer waste and produce alternative fuel sources. One of the promising areas in this field is the thermocatalytic decomposition of plastics into hydrocarbon fractions suitable for use as motor fuel. This study investigates the feasibility of using natural Taizhuzgen zeolite separately modified with molybdenum and tungsten and activated by an acid-free method for the thermocatalytic hydrogenation of polymer waste. The catalyst was prepared by modifying the activated zeolite with molybdenum ((NH4)6Mo7O24·4H2O) and tungsten ((NH4)5H5[H2(WO4)6]·H2O) salts. Thermal catalytic hydrogenation experiments were conducted under controlled temperature and barometric conditions, and the resulting liquid products were separated into fractions with boiling points of 180 °C, 180–250 °C, and 250–320 °C. The individual and group hydrocarbon compositions of the gasoline, diesel, and heavy gas oil fractions were determined using gas chromatography–mass spectrometry. The structural and surface characteristics of the synthesized composite catalysts were studied using electron microscopy and physicochemical analysis. The results show that Taizhuzgen zeolite modified with molybdenum and tungsten exhibits favorable textural properties and catalytic activity, which increases the yield of liquid fuel fractions. The developed catalyst is promising for use in the resource-efficient thermal catalytic processing of polymer waste into motor fuel.