Recovery of value-added products from the pyrolytic recycling of glass-fibre-reinforced composite plastic waste

A range of fibre-reinforced plastic composites have been pyrolysed in a fixed bed reactor and the product yield and oil/wax and gas composition investigated. There are a wide range of composite plastic samples in use and the pyrolysis product gas and oil/wax composition reflect this variety. Detailed examination of a representative composite plastic waste in the form of a mixed polyester/ styrene composite was carried out on a larger scale and the properties of the derived products examined for their potential as value-added products. The oil derived from pyrolysis had fuel properties similar to a petroleum-derived gas oil, in terms of viscosity, sulphur content and distillation range. However, the calorific value was lower due mainly to the higher oxygen content of the oil. In addition, the main component of the oil was styrene comprising 26 wt% of the oil. A wax product consisting of approximately 15 wt% of the original plastic composite consisted almost entirely of phthalic anhydride, a useful chemical feedstock. The glass fibre used in the composite formulation was separated from the char and filler of the solid residue and investigated for its strength properties. The potential use of the glass fibre as replacement in new composite products was demonstrated.