Modelling and Simulation of Waste Plastic Power Plant: A Theoretical Framework

The high energy content of plastics can be converted to electricity. The recovery of this abundant energy helps to curb environmental concerns associated with plastic utilization. Non-recyclable plastic materials are used in areas like packaging, 3D printing, and construction. Where recycling becomes an issue, technologies that utilize the waste plastics to generate electricity can be employed. This paper presents a theoretical framework for the simulation of waste plastic power plant. A simulation model that produces electricity from the High Density Polyethylene (HDPE) waste plastics has been developed using Aspen Hysys process simulator. The pyrolysis reactor modelled as a conversion reactor was used to thermally crack 2000Kg/h of HDPE feed at a temperature of 450°C to produce a top product containing a mixture of liquid fuel oil and volatile gaseous fuel. After cooling of the top product and separation to obtain the volatile gaseous fuel from the liquid fuel oil, the volatile gaseous fuel alongside air were pressurized with a compressor and then combusted in a Gibbs free energy reactor. In this reactor, the gaseous fuel burned with excess air in the combustion chamber to produce a high temperature and pressured gas that drove the gas turbine (modelled as an expander) to generate electrical power of 1194KW. To achieve proper energy optimization, the high temperature flue gas obtained from the gas turbine after pressure loss was passed through a “Heat Recovery Steam Generator” that allowed water at 25°C to be heated up to produce steam which in turn drove a steam turbine to generate electricity of 255.3KW. In all, the waste plastic power plant generated a net power of 216.461KW at an equivalence ratio of 1.5.