Molten waste plastic pyrolysis in a vertical falling film reactor and the influence of temperature on the pyrolysis products

Molten plastics are characterised with high viscosity and low thermal conductivity. Applying falling film pyrolysis reactor to deal with waste plastics can not only improve heat transfer efficiency, but also solve the flow problem. The pyrolysis process of molten polypropylene (PP) in a vertical falling film reactor was studied experimentally, and the products are collected by fractional condensation. The yield of pyrolysis oil decreases from 74.4 wt% (± 2.2 wt%) to 53.5 wt% (± 1.3 wt%) when the temperature increases from 550 °C to 625 °C, and the main components are alkenes and naphthenes. The yield of oil from the vertical falling film pyrolysis reactor is slightly higher than that from the tubular reactor, equal to that from the rotary kiln reactor, and slightly lower than that in the medium fluidised-bed reactor. The content of the light fraction C6-C12 of pyrolysis oil is 69.7 wt%.150