Copyrolysis of oils/waxes of individual and mixed polyalkenes cracking products with petroleum fraction

Copyrolysis of 10 mass% solutions (oils/waxes from individual or mixed polymers with heavy naphtha) is a route for treatment of plastic waste. Linear low-density polyethylene (LLDPE), mixture of high-density polyethylene/low-density polyethylene/linear low-density polyethylene/polypropylene (HDPE/LDPE/LLDPE/PP = 1:1:1:1mass) and linear low-density polyethylene/low-density polyethylene/polypropylene/high-density polyethylene/polyvinyl chloride/polyethylene terepthalate/polystyrene (LLDPE/LDPE/PP/HDPE/PVC/PET/PS = 1:1:2:2:0.05:0.05:0.156 mass) were converted to oils/waxes, gases and solid residues by thermal decomposition in batch reactor at 450 °C. Oils/waxes were dissolved in virgin heavy naphtha to create the feedstock. The influence of residence time from 0.08 to 0.51 s at temperatures 780 °C and 820 °C on product distribution during the copyrolysis was studied. The yields obtained from gaseous and liquid products of solutions are compared to the yields obtained from virgin heavy naphtha. It was studied how addition of the oil/wax influences formation of C₂ and C₃ hydrocarbons (mainly ethene and propene) and aromatics in comparison to the virgin heavy naphtha. The ethene and propene yields from copyrolysis of solutions are comparable or higher than from virgin heavy naphtha. Copyrolysis of solution LLDPE/LDPE/PP/HDPE/PVC/PET/PS gives the maximum yields of propene from all studied oils/waxes. The result suggests that oils/waxes from polymers are suitable feedstocks for copyrolysis with virgin heavy naphtha.