Design of Dimethyl Carbonate (DMC) synthesis process using CO2, techno-economic analysis and life cycle assessment

Abstract

Abstract To successfully attain the objective of carbon neutrality, the active incorporation of carbon capture utilization (CCU) technology becomes imperative within the engineering framework. This technology facilitates the generation of high value-added materials by harnessing carbon dioxide, sourced from either the atmosphere or industrial processes, as a fundamental raw material. Dimethyl carbonate (DMC) is an environmentally friendly chemical that can be produced using CCU technology. This study first models the base process of the ethylene carbonate (EC) transesterification method that produces DMC based on carbon dioxide, ethylene oxide (EO), and methanol (MeOH). Based on this, three processes for recycling by-products ethylene glycol (EG) and EC are proposed, and economic analysis and overall environmental impact evaluation are conducted. Each process is modeled through Aspen Plus V12.1, economic feasibility is evaluated through Aspen Process Economic Analyzer (APEA), and environmental impact is evaluated through OpenLCA. As a result, the results show that the final DMC production is increased by 0.644%-18.9% compared to the base process in the process of recycling by-products. In the base process, the net present value (NPV) and pay-back period (PBP) were 46 M$ and 8.3 years, respectively, and in the proposed 1 (recycling EG) and proposed 3 (recycling EG&EC) processes, the NPV was 231 M$ and 73 M$, respectively, and the PBP was 3.8 years and 7.4 years, respectively. In the proposed Process 2 (with EC recycling), a substantial negative net present value (NPV) of -135 M$ was observed, indicating that recovering the investment cost was unfeasible within this scenario. Through sensitivity analysis, it was shown that the parameters with high volatility of NPV are DMC price and raw material cost. Finally, the result for climate change among the environmental impact categories is 3.85 kgCO2-eq in the base process, 3.47 kgCO2-eq in the proposed 1 process, 3.57 kgCO2-eq in the proposed 2 process, and 3.33 kgCO2-eq in the proposed 3 process, respectively.