Studies on Thermal Decomposition of Plastic Wastes (II)

Abstract

There have been many new developments concerning the studies on the pyrolysis of plastic wastes. Our investigation was that the plastic wastes were converted into the fuel oil or monomers of plastics. The plant was consisted essentially of a steel tube with a single screw and an electric furnace, a condensing and scrubbing train for the product recovery, and gas-metering and sampling devices.The experiments in which the high boiling point oil (or residne) in the pyrolysis products or waste lubricating oil were mixed with the waste plastics and then pyrolized at 400-600°C were carried out. We called this process the solvent method. The following results were obtained.This solvent method was well suited to the thermal decomposition of polyolefins or polystyrene and the manufacture of gasoous fuel and fuel oil or the monomer of of plastics. The gaseous product in the pyrolysis of polyolefins at 500-57°C showed about 10-35wt% yields and it contained olefins at 60-80wt%. In the case of polystyrene, about 50-70wt% of styrene were recovered as monomer. The higher boiling oils were been able to recycle to the feed of pyrolysis as solvent.