Product Composition from the Fast Pyrolysis of Polystyrene

Abstract

Abstract Polystyrene has been pyrolysed in a fluidised bed pyrolysis reactor and the influence of pyrolysis temperature from 500 to 700°C on the yield and composition of the derived products has been determined. The main products from pyrolysis of polystyrene were a wax/oil product collected, as a condensed wax fraction and a separate oil fraction, using an industrial demister system. The oils and waxes were analysed by size exclusion chromatography to determine their molecular weight distribution, by Fourier transform infra-red spectrometry to determine their functional group composition and by gas chromatography to determine their detailed composition. The derived oils had a molecular weight distribution from 60 to 200 Da, with higher molecular weight material occurring in the wax fraction with a distribution of 60 to over 1000. Detailed analysis of the oils showed that the pyrolysis of polystyrene gave a mainly aromatic composition dominated by styrene and styrene oligomers. The oils also contained polycyclic aromatic hydrocarbons which increased in concentration as the pyrolysis temperature was increased to 700°C. Low concentrations of hydrogen, methane, ethane, ethene, propane, propene, butane and butene were also formed. There was an increase in gas yield with increasing temperature of pyrolysis. Keywords: Pyrolysisplasticspolystyrenerecycling