Fast pyrolysis of fibre waste contaminated with plastic for use as fuel products

Abstract

Pyrolysis is finding increasing application as a tool for the effective management of industrial waste, as it can process a wide variety of heterogeneous feedstock into energy dense products. Inductively heated fast pyrolysis with heating rate of 250 °C min−1 was applied for conversion of three industrial waste streams from a fibre recycling mill, contaminated with plastic wastes, into energy products. Experiments were carried out at three different temperatures (350, 450 and 550 °C) and the yields and energy contents of the char, oil, wax and gas products were determined. For all three waste streams, conversion at 350 °C, mostly concentrated the energy in the char, resulting in calorific values between 20.9 MJ kg−1 and 35.1 MJ kg−1 which are comparable to common bituminous coal used for power generation. Pyrolysis at 450 or 550 °C promoted the formation of condensable volatiles (wax/liquid) with total wax yields of up to 54 wt.% being obtained at 550 °C, with the calorific value up to 41.7 MJ kg−1 comparable to heavy fuel oil. The estimated net energy yield for the three waste streams ranged from 10 to 25 MJ (kg dry feedstock)−1 with the largest energy yield being obtained for the stream containing the largest fraction of hydrocarbon plastics.