Production of an Alternative Fuel by Pyrolysis of Plastic Wastes Mixtures

This paper tries to obtain an alternative liquid fuel from plastic waste from the fraction not collected selectively, through a pyrolysis process. The fuels obtained from three plastic wastes, polyethylene (PE), polypropylene (PP), and polystyrene (PS), and from binary mixtures (PE–PP and PE–PS) and a tertiary mixture (PE–PP–PS) were characterized. These plastic wastes are the most abundant in the fraction not collected selectively. Concretely, the polyethylene film comprises 43% of total plastic of this fraction. The plastic mixtures have been chosen according to the composition of the plastic in this fraction. Liquid fuel from the polyethylene film had very similar characteristics to commercial fuels, in particular, diesel, but had a very high viscosity and a waxy appearance. Liquid fuel from polystyrene had a very fluid appearance, but possessed a large number of aromatic compounds, being useful for the synthesis of basic chemical products. The liquid obtained from polypropylene has a semiwaxy appearance and a large number of olefins. Finally, the mixtures of these wastes produced intermediate characteristics. The viscosity and waxy aspect increases when the quantity of polyethylene increases, while fluidity and the quantity of aromatic compounds also increase when the quantity of polystyrene increases.