This study presents comprehensive process simulations, reactor design analyses, and technoeconomic evaluations for ethylene production from carbonates. It begins with CO2 capture and ends with product separation and stream recycling. Process simulations underscored the critical role of the CO2 source—whether direct air capture (DAC) or flue gas—in determining economic viability, contingent upon the target product. Simulations also highlight the necessity of concentrating carbonate feed streams via membranes operable under alkaline conditions, which is vital for economic feasibility. Detailed examinations of electrolyzer design through computational fluid dynamics and residence time distribution studies, in addition to analyzing the effect of scaling, configuration, and nonlinear cost modeling were conducted to better account for economies of scale relevant to electrochemical systems.
Three scenarios, including the current state of the art, were analyzed to elucidate key focus areas and serve as a guide for experimentalists. Projected performance metrics for viable large-scale production reveal comparable economic feasibility between DAC and flue gas capture scenarios (<8% cost difference). Optimized BPM processes can achieve minimum selling prices (MSP) of $0.9/kg ethylene over a 20-year plant lifespan, rivaling naphtha-based ethylene and surpassing conventional CO2 gas-fed systems.
This approach highlights the potential for BPM-based aqueous carbonate conversion to support sustainable and economically competitive chemical production, such as ethylene and syngas, provided ongoing advancements in process efficiency and scalability are achieved.
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Nat. Chem. Eng. 2024, 1, 11, 710–723 DOI: https://doi.org/10.1038/s44286-024-00137-y