Post-Consumer Polyurethane Foam Depolymerization into Toluene Diamine and Polyether Triol for Circular Regeneration of Polyurethane
Polyurethane (PU) foam is integral to our everyday lives, as it is a versatile and ubiquitous material used in construction, automotive, furniture, and packaging applications. However, the widespread use of PU foam has also raised environmental concerns, particularly its contribution to landfill waste and volatile organic compounds (VOC) emissions. Approaching such global waste issues to mitigate existing climate, health, and economic impacts creates new opportunities for scientific and engineering development. To address this problem, this report proposes a chemical plant using patented information from Evonik to depolymerize 100,000 metric tons of post-consumer PU foam annually into toluene diamine (TDA) and polyether triol (PPO-3OH) to be established in the U.S. Gulf Coast and operate 24 hours per day for 330 days per year. The process uses 4 batch reactors, each operating 4 times per day at a temperature of 130°C and pressure of 3.03atm for 5 hours per operation. The design includes two continuous separation processes to produce pure TDA and PPO-3OH streams. Preprocessing equipment is also included in the design to compress and pelletize the PU foam feedstock before it enters the reactors. This project’s internal rate of return (IRR) is 17.74%, and the return on investment (ROI) is 16.94%. Considering the profitability of this procedure, this depolymerization plant is proposed as an autonomous operation from an economic perspective. While this procedure emits greenhouse gases in the form of carbon dioxide (CO2), a system that allows the plant to be situated with carbon capture companies to curb these emissions. This process promotes the circularity of the PU foam recycling sector and produces high-quality items sustainably and innovatively.