Pyrolysis of a fraction of waste polypropylene and polyethylene for the recovery of BTX aromatics using a fluidized bed reactor

Fractions of waste polypropylene and polyethylene were pyrolyzed in a pyrolysis plant under different conditions. In this study, the influence of the reaction temperature (650–750 °C), the feed rate, and the kind of fluidizing medium on the product spectrum were investigated. Pyrolysis of the PP fraction produced oils up to 43 wt. % of the product. With respect to the PE fraction, the maximum oil yield was above 60 wt. % of the product. The target compound was BTX aromatics, whose amount in the oils reached 53 wt.% for the PP fraction and 32 wt. % for the PE fraction. It was shown that the PE fraction yielded a higher liquid product compared to the PP fraction, and that the concentration of aromatics in the oil increased at higher reaction temperatures for both the PP and PE fractions. A higher feed rate and the use of a gas product as the fluidizing medium were favored for the production of oils for both the PP and PE fractions. The oils that were obtained in the experiments almost had no metal and chlorine contents. The maximum heating value of the gas obtained in the experiments was about 50 MJ/kg.