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.

塑料废弃物处理是循环经济模型与能源转型领域的关键分支，因聚合物前驱体（polymer precursors）是化工行业主要的能源与原材料消耗主体之一。本研究梳理了该领域的前沿发展现状，并致力于填补高杂质低质量塑料废弃物化学增值（chemical valorization）领域现存的研究空白。所提出的技术路径旨在通过气化工艺将塑料废弃物转化为甲醇。该工艺通过结合原料热力学表征与合成气处理动力学建模完成开发与模拟。研究在聚丙烯/聚乙烯混合原料中引入不同比例的聚苯乙烯，以评估该工艺在氢含量较低的原料中的运行特性。针对每种原料评估该工艺的性能表现，并以此为基础测算该技术的运营支出，同时针对不同装置规模评估其净现值（net present value）与内部收益率（internal rate of return）。