Influence of waste sorting on the effectiveness of polymeric waste pyrolysis

Abstract

Pyrolysis of polymeric wastes, including waste plastic bottles, discarded rubber tyres and pure water sachets, is one of the environmental-friendly processes for waste valorization. However, continuous effort must be made to reduce the cost implication of the pyrolysis process in terms of time, money and energy requirement. Based on this premise, this study examined the justification regarding heat absorption rate and product yield, for sorting polymeric waste mixture before the pyrolysis process. The objective was achieved by carrying out pyrolysis of the separated and mixed plastic bottle, rubber tyre and water nylon sachet wastes using a semi batch pyrolysis system. The results indicated that at residence time of 100 minutes, maximum heat absorption rates of 128.63 and 89.38 kJ/min were obtained for pyrolysis of separated and mixed wastes, respectively, of plastic bottles and rubber tyres. For the pyrolysis of separated and mixed wastes of plastic bottles, rubber tyres and water nylon sachets; maximum heat absorption rates of 144.56 and 119.46 kJ/min, respectively, were obtained. It was also observed that the amounts of pyrolytic products produced after the pyrolysis of the separated polymeric wastes were greater than the amounts obtained after the pyrolysis of the mixed polymeric wastes. This indicates that sorting polymeric wastes into different categories before pyrolysis contributes to effective pyrolysis process.