This study proposes an integrated oxidative coupling of methane (OCM) process for the co-production of ethylene and hydrogen, aiming to overcome the limitations of conventional single-reactor OCM and improve system-level performance while addressing resource sustainability in ethylene production. The proposed processes employ a two-stage isothermal reaction system to improve methane conversion and C 2 selectivity, combined with an alternative separation strategy and on-site energy recovery via combined heat and power integration. Rigorous process simulations were conducted to establish mass and energy balances, followed by comprehensive techno-economic and environmental analysis. The optimal configuration achieved an ethylene unit production cost of 0. 97 USD/kg, representing a 55. 9% reduction relative to a conventional single-reactor OCM benchmark (2. 2 USD/kg), driven by staged conversion, elimination of methane recycles, and hydrogen coproduction. Net CO 2 -equivalent emissions were reduced by 66. 2% to 4. 50 kg CO 2 per kg C 2 H 4. Sensitivity analysis identified hydrogen value, methane price, and the methane/oxygen ratio as key determinants of economic feasibility. A multi-metric assessment incorporating energy use, carbon efficiency, feedstock availability, and price elasticity shows that methane-based direct conversion pathways exhibit favorable structural characteristics, particularly in terms of feedstock robustness. These results provide practical solutions to cost-competitively diversify resources for ethylene production, while leveraging emerging hydrogen markets. • Two-stage OCM reactors improve methane conversion and ethylene selectivity. • A developed process enables co-production of ethylene and hydrogen. • Ethylene unit production cost reaches 0. 97 /kg, 55. 9% lower than benchmark. • Net CO 2-eq emissions reduced to 4. 50 kg CO 2 per kg of ethylene, 66. 2% improvement. • Multi-metric assessment supports methane-based routes for sustainable ethylene production.
Chung et al. (Sun,) studied this question.