Simulation and obtaining of synthetic fuels from the pyrolysis of plastic wastes

Abstract

The continuous demand for plastics has caused large accumulations of waste in landfills, contributing to environmental and public health problems. In Colombia, approximately 9.5 million tons of solid waste is generated annually, and 14% corresponds to plastic materials. Pyrolysis is a technique by which it is possible to remedy part of the problem, because energy and products are recovered in the form of liquid and gaseous fuel. This article presents the implementation and comparison of two models in Aspen Plus for the simulation of the pyrolysis process for the production of liquid fuels from different plastic waste. The models are based on the minimization of Gibbs free energy and reaction kinetic mechanisms. The simulation performed calculates the yields (% of weight) and the properties of each product flow according to the operating conditions. In comparison with data from the literature and experimental information collected in this research, the thermodynamic model showed deviations greater than 20%. The kinetic model presented good estimates obtaining errors ? 8%. According to the results obtained, the production of liquid fuel from plastic wastes is favored according to the raw material as follows: polystyrene > high density polyethylene ? low density polyethylene > polyethylene terephthalate.