General Scheme of Waste Polyolefin Processing

Chemical composition of waste plastic cracking products depends on shares of the individual polymers (PE, PP, PS) in the feed and process parameters. This fact decides the technological application of the final products. Important products of the cracking process, both petroleum fractions and waste plastics, are coke residues. Coke residue yield increases considerably, up to 10 wt%, in cracking of municipal and industrial waste plastics since they contain various inorganic impurities and additives. It can be applied as solid fuel, like brown coal. In the fluid cracking the solid residue is continuously removed from the process by combustion in a regenerator section. 

Waste plastics potentially can also be processed in hydrocracking process as an additional feed stream in mixture with vacuum gas oil or crude oil residues. Careful plastic segregation is then necessary since inorganic additives and impurities of plastics can foul the hydrocracking catalyst. Noncatalytic high-temperature olefin pyrolysis (700-800°C) and coking are insensitive to fouling. 

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