A Fast Computational Framework for the Design of Solvent-Based Plastic Recycling Processes

Abstract

Multilayer plastic films are widely used in packaging applications because of their unique properties. These materials combine several layers of different polymers to protect food and pharmaceuticals from external factors such as oxygen, water, temperature, and light. Unfortunately, this design complexity also hinders the use of traditional recycling methods, such as mechanical recycling. Solvent-based separation processes are a promising alternative to recover high-quality pure polymers from multilayer film waste. One such process is the Solvent-Targeted Recovery and Precipitation (STRAPTM) process, which uses sequential solvent washes to selectively dissolve and separate the constituent components of multilayer films. The STRAPTM process design (separation sequence, solvents, operating conditions) changes significantly depending on the design of the multilayer film (the number of layers and types of polymers). Quantifying the economic and environmental benefits of alternative process designs is essential to provide insights into sustainable recycling and film (product) design. In this work, we present a fast computational framework that integrates molecular-scale models, process modeling, techno-economic and life-cycle analysis to evaluate STRAPTM designs. The computational framework is general and can be used for complex multilayer films or multicomponent plastic waste streams. We apply the proposed framework to a multilayer film commonly used in industrial food packaging. We identify process design configurations with the lowest economic and environmental impact. Our analysis reveals trends that can help guide process and product design.