(390w) Multi-Scale Integration of Multiphysics and Process Models for CO2 Electrolyzers with Techno-Economic and Environmental Optimization

Carbon dioxide electrochemical reduction reaction (CO₂RR) is a key technology for reducing greenhouse gases while producing high value-added chemicals. Accordingly, integrated analysis of techno-economic analysis (TEA) and life-cycle assessment (LCA) of CO₂RR at process scale for commercialization becomes important. Previous studies have used simplified models that do not sufficiently reflect the physical behavior inside the electrolyzers [1]. Although the correlation between current density, cell voltage, and Faraday efficiency has been widely reported experimentally [2,3], they have often been treated as independent variables in process scale evaluations [4-6]. Recently, there have been attempts to emphasize the interrelationship between the electrolyzer model and the process model [7], and to evaluate economic feasibility based on the voltametric model [8]. However, physical phenomena in electrolyzers, such as mass transfer and reaction kinetics, are often overlooked in TEA/LCA analyses, and simplified models run the risk of distorting the economic and environmental performance of system design and operating conditions.

To address the limitations, we developed a multi-scale TEA/LCA analysis platform that links electrolyzer-level models with process-level models. It integrates the finite element method (FEM)-based CFD Multiphysics model with Aspen Plus process simulation, with the two levels designed to interlock boundary conditions. The structure allows for simultaneous consideration of electrolyzer design variables such as catalyst layer thickness and membrane type, as well as process operating conditions such as cell voltage, CO₂ flow rate, temperature and humidity. This framework can be extended to other electrochemical systems, such as the chlor-alkali process, ammonia synthesis process, and carbon monoxide reduction. Ultimately, the simultaneous multi-scale optimization of electrolyzer design variables and process operation variables together provided practical design guidance for the commercialization of CO₂RR. It was performed using derivative-free optimization, and the target functions to be minimized are levelized cost of chemical and global warming impact. This study is significant in that it precisely reflects the realistic operating conditions and enables optimization that considers the complex interaction between design and operating conditions.

References

1. Somoza-Tornos A, Guerra OJ, Crow AM, Smith WA, Hodge B-M. Process modeling, techno-economic assessment, and life cycle assessment of the electrochemical reduction of CO2: a review. iScience. 2021;24(7):102813.

2. Gao D, Zhang Y, Zhou Z, Cai F, Zhao X, Huang W, et al. Enhancing CO2 Electroreduction with the Metal–Oxide Interface. Journal of the American Chemical Society. 2017;139(16):5652-5.

3. Varela AS, Kroschel M, Reier T, Strasser P. Controlling the selectivity of CO2 electroreduction on copper: The effect of the electrolyte concentration and the importance of the local pH. Catalysis Today. 2016;260:8-13.

4. Jouny M, Luc W, Jiao F. General Techno-Economic Analysis of CO2 Electrolysis Systems. Industrial & Engineering Chemistry Research. 2018;57(6):2165-77.

5. Na J, Seo B, Kim J, Lee CW, Lee H, Hwang YJ, et al. General technoeconomic analysis for electrochemical coproduction coupling carbon dioxide reduction with organic oxidation. Nature Communications. 2019;10(1):5193.

6. Spurgeon JM, Kumar B. A comparative technoeconomic analysis of pathways for commercial electrochemical CO2 reduction to liquid products. Energy & Environmental Science. 2018;11(6):1536-51.

7. Bagemihl I, Cammann L, Pérez-Fortes M, van Steijn V, van Ommen JR. Techno-economic Assessment of CO2 Electrolysis: How Interdependencies between Model Variables Propagate Across Different Modeling Scales. ACS Sustainable Chemistry & Engineering. 2023;11(27):10130-41.

8. Shin H, Hansen KU, Jiao F. Techno-economic assessment of low-temperature carbon dioxide electrolysis. Nature Sustainability. 2021;4(10):911-9.