Pyrolysis of Auto Shredder Wastes to Produce Liquid Biofuels

Granulated plastics from automobile shredder wastes were subject to pyrolysis atdifferent temperatures (300ºC to 430ºC), different nitrogen pressures (30 psi to 150 psi)and different residence times (1s to 120 min). The wastes were converted to pyrolysisproducts with predominance of gases and liquids. The liquid phase was fractionated bydistillation to yield a light fraction (T<150ºC) and a heavy fraction (150ºC>T>300ºC). Thesolid products were sequentially extracted with dichloromethane and tetrahydrofurane torecover the liquid products retained in the solid pores. Liquid products and extracts werecharacterized by GC-FID (gas chromatography with flame ionization detector), and theproducts with boiling points lower than 270 ºC were further characterized by GC-MS (gaschromatography with mass spectrometry). The light fraction is mainly composed byaliphatic hydrocarbons with high amounts of low boiling point components such as 2-butene. The heavier fraction contains linear alkanes and alkenes but also cyclichydrocarbons including cyclohexane derivatives and some alkylbenzenes.These results indicate that these wastes can be successfully recycled to yield biogasolineand green-diesel, contributing to a replacement of fossil fuels and simultaneouslyeliminating significant amounts of hazardous wastes that necessarily increase with thegrowth in the automobile production industry.