Municipal Plastic Waste Recycling through Pyrogasification

Abstract

Conventional mechanical recycling technologies cannot recycle all types and amounts of generated plastic waste. Pyrolysis can convert these municipal mixed plastic streams into products with significant calorific value, which are likely to be used as energy sources. The present work describes a technology used to expand the portfolio of technical approaches to drive plastics circularity, i.e., thermochemical recycling. A base case scenario considered a capacity of 1.000 kg/h of municipal plastic waste, consisting of a mixture of polypropylene (PP), polystyrene (PS), polyethylene (PE), and plastic associated with paper, which were converted into non-condensable gases, oil, and char through a pyrogasification system. Based on mass and energy balances and experimental data from the literature, a total of 199.4 kg (48 MJ/kg) of liquid fuel and 832.85 kg (16 MJ/kg) of gas could be obtained with no need for external heating sources. The thermal requirement for the pyrolysis of 1.000 kg of municipal plastic waste (1.316 MJ) was supplied by the gasification of a fraction of the produced pyrolysis oil and gases. This feasibility analysis confirmed the technical adequacy of the proposed technology, which that will be further complemented by a technoeconomic study of the proposed solution.