Investigation of gasoline-like transportation fuel obtained by plastic waste pyrolysis and distillation

Abstract

Gasoline-like hydrocarbon products obtained from the distillation of different pyrolysis oils produced from solid wastes of polypropylene (PP), polystyrene (PS), polyethylene (PE), and their blends were investigated as these materials together form a good candidate for providing gasoline with properties approaching or fulfilling standard requirements in various countries. A laboratory-scale batch reactor equipped with reflux was used in this research, while the gasoline fractions of pyrolysis oils processed by distillation were further analyzed by GC-MS. Fuel density, volatility, distillation curves, olefin content, aromatics (including benzene) content, and oxygenates were analyzed, and various scenarios were proposed for reaching standard quality. The results were compared to a commercial gasoline sample from Hungary. It was found that the gasoline-like product of low-density PE (LDPE) and high-density PE (HDPE) showed the most similarities to standard requirements regarding molecular distribution. The PS produced mainly aromatics, while the gasoline yield of PP contained 53.5 vol% 2,4-dimethyl-1-heptene, which severely affects the distillation requirements presented by gasoline fuel standards. The results show that the mass ratio of plastic materials used in the pyrolysis process can heavily influence the oil products’ applicability as a transportation fuel. The optimal plastic waste mixture combined with the saturation of the olefin content by catalytic hydrogenation can provide standard-quality gasoline.