Process Simulation of 1,4-Cyclohexanedimethanol Production from Waste PETs

The increasing accumulation of plastic waste, particularly poly(ethylene terephthalate) (PET), necessitates sustainable recycling strategies. This study presents a process design for producing 1,4-cyclohexanedimethanol (CHDM) via chemical recycling of post-consumer PET using bis(2-hydroxyethyl) terephthalate (BHET) as an intermediate. The proposed process includes PET glycolysis followed by BHET hydrogenation and was modeled and simulated using Aspen Plus and Aspen EDR. A production capacity of 7920 tons of PET annually was selected, resulting in 5000 tons/year of CHDM with 97.4% purity. Thermodynamic models (POLYUF, POLYSL, and NRTL-HOC) were applied across various process stages. Kinetic parameters were derived from the literature and simulation databases. Equipment sizing, energy integration, and economic analysis were performed, and the total production cost was estimated at 46.7 million USD. A profitability analysis via CAPCOST revealed a net present value of 4.39 million USD, a discounted cash flow rate of return of 16.14%, and a discounted payback period (DPBP) of 3.8 years. These results indicate that CHDM production from PET waste is both technically and economically viable, providing an environmentally friendly valorization pathway for plastic waste.