(516h) Process Modeling and Comparative Assessment of Solvent-Based Polyolefin Recycling Technologies

Mechanical recycling remains the dominant method for recycling polyolefins, but it is fundamentally limited by its inability to process contaminated or multilayer materials. In response to growing consumer demand for high-quality recycled content in plastic packaging, the polymer industry has shown increased interest in advanced recycling technologies and their resulting products. Among these, solvent-based recycling has emerged as a promising technology capable of producing virgin-like recycled polymers.

Solvent-based recycling dissolves a target polymer in a suitable solvent, swelling the matrix to enhance contaminant removal without degrading the polymer. Despite the growing attention on solvent-based recycling of polyolefins, there has been limited work on rigorous process modeling of these technologies. In particular, existing studies often neglect downstream separations and purification, which often represent the most energy-intensive parts of the process. This work addresses this gap by developing detailed process models that integrate dissolution, purification, precipitation, and devolatilization steps.

We evaluate and compare multiple process configurations for the solvent-based recycling of polyolefins, specifically polyethylene and polypropylene, including antisolvent precipitation, supercritical fluid dissolution, and subcritical temperature/pressure-induced precipitation. These models investigate the limitations of each process configuration in handling different types and concentrations of feedstock contamination, highlighting how these processes must be tailored to expected feedstock characteristics. We also explicitly model polymer fractionation to examine how variations in molecular weight distribution affect processing conditions and overall process efficiency. To address the high energy demands of precipitation and devolatilization, we apply heat integration and explore process intensification strategies. This comprehensive modeling effort offers a deeper insight into the industrial deployment of solvent-based recycling and the key challenges that must be addressed for scalable implementation.