Solar assisted pyrolysis system for High-Density polyethylene plastic waste to fuel conversion

Abstract

Plastic products are used almost in all our daily life activities due to their characteristics such as being inert, durability, flexibility, and versatility. More than 1 million tons of plastic wastes are generated daily in Ethiopia. Unless managed it properly plastic waste affects the environment immensely since they are durable and stable. Plastic wastes stay in the environment for a long time. In this paper, a solar-assisted pyrolysis system has been designed and tested for the generation of liquid fuel from High-Density Polyethylene plastic waste. Data were collected related to the solar energy potential of Addis Ababa city of Ethiopia and the amount of plastic waste generated daily. Proximate and ultimate analysis and heating value of waste were determined experimentally. The energy requirements of the pyrolysis system were determined and the sizing of the system was performed. The model is simulated using Matlab software and a mathematical model is applied to study the performance of the system. A 4 m diameter solar parabolic dish collector with a cylindrical-shaped reactor at the focal point and dual solar tracking system is used based on Addis Ababa weather data and the required energy for the endothermic pyrolysis. Based on the result, the conversion efficiency of the system is 72% by weight. The result also shows 1360 Kwh/m2 of solar energy is required to produce 14.2 liters of liquid fuel from High-Density Polyethylene plastic waste. The heating value of the produced liquid fuel is 41.8 MJ/kg. Thus, by using a solar-assisted pyrolysis system a liquid fuel has been produced from plastic waste, income is generated from the selling of the produced liquid fuel, and the environmental impact of waste plastic is reduced.