Techno economic analysis of diethyl carbonate production via oxidative carbonylation of bioethanol

Abstract

The increasing adoption of electric vehicles in Thailand is expected to reduce domestic gasohol demand, thereby negatively impacting the bioethanol industry. To address this challenge, this study analyzed the techno-economic performance of diethyl carbonate (DEC) production via oxidative carbonylation of bioethanol, given DEC’s growing importance as a battery-grade electrolyte solvent for lithium-ion batteries. Process simulation was conducted using Aspen Plus V14 and economic evaluation was performed using Aspen Process Economic Analyzer (APEA) at an annual production capacity of 4,000 tonnes, targeting DEC purity of ≥ 99.99 wt%. Four cases were investigated: liquid-phase and gas-phase oxidative carbonylation (Cases I and II), and the corresponding cases incorporating a heat exchanger network (Cases III and IV). Simulation results showed good agreement with experimental data for both configurations. The gas-phase process required substantially lower raw material consumption owing to its 100% DEC selectivity, which also simplified the separation section. Composite curve analysis indicated limited heat integration potential for both configurations, and HEN implementation resulted in marginal reductions in specific energy consumption without improving economic performance. The environmental impact assessment revealed that HEN combined with NQ-curve optimization marginally reduced emissions for the gas-phase process. Flammability analysis confirmed that all key process streams operate above the upper flammability limit under normal steady-state conditions. Overall, the gas-phase oxidative carbonylation without heat integration combined with NQ-curve optimization represented the most technically and economically favourable configuration. While HEN combined with NQ-curve optimization contributed to reductions in energy consumption and emissions, it did not improve economic performance as the additional capital investment was not justified by the marginal operating cost savings. The findings support the feasibility of bioethanol-based DEC production as a promising value-added pathway for Thailand’s bioethanol industry.