Design and Simulation of a Plastic Waste to Methanol Process: Yields and Economics

Plastic waste treatment is a key sector for circular economic models as well as for the energy transition since polymer precursors are among the main energy and raw material consumers of the chemical sector. This work analyzes the state of the art of the sector and tries to fill the gap present for chemical valorization of low quality plastic waste with a high impurity content. The proposed path aims at converting plastic waste to methanol through gasification. The process is developed and simulated with a combination of thermodynamic characterization of the feedstock and kinetic modeling of syngas treatments. Different loads of polystyrene in a polypropylene/polyethylene mixture are used to evaluate the behavior of the process for a less hydrogen-rich feedstock. The performance of the process is evaluated for each feedstock and used as a basis for an assessment of the operative expenditures of the technology, as well as evaluating the net present value and internal rate of return at different plant capacities.