Modeling and optimization of a sustainable ε-caprolactam production process from phenol: a simulation-based approach

This study presents a sustainable and simulation-driven production process for ε-caprolactam (CPL) using phenol as a feedstock, offering a green and economically viable alternative to conventional benzene-based routes. The process integrates three catalytic stages – Pt/SiO 2 -mediated hydrogenation, TS-1-catalyzed ammoximation, and oleum-assisted Beckmann rearrangement – all modeled and optimized in Aspen Plus. The optimized configuration achieves a CPL yield of 68 %, reduces CO 2 emissions by 30 %, and lowers total energy consumption by 12 % through integrated heat recovery. Additionally, wastewater treatment enables 60 % water reuse. Techno-economic analysis confirms commercial viability, with a Net Present Value (NPV) of BND 8.2 million and a payback period of 3.9 years for an 80,000-ton/year plant. This work delivers a validated and modular framework for CPL production aligned with circular economy principles. Future research will focus on process intensification, bio-based phenol utilization, and deployment of green hydrogen sources for full lifecycle decarbonization.