(338f) Comparative TEA and LCA Study for Integrated Process of Direct Air Capture and Captured CO2 Conversion

The atmospheric CO₂ concentration driven by the increasing impacts of greenhouse gas has reached 440 ppm, demanding efficient carbon dioxide reduction technologies [1]. While previous studies focused on flue gas, leaving a noticeable gap in the investigation of atmospheric CO₂ capture and highlighting the need for direct air capture [2]. This approach necessitates the investigation of reactive capture and conversion (RCC) technologies, which eliminate the need for a regenerator in conventional systems, thereby simplifying the process and enhancing economic benefits [3]. Therefore, we are studying direct air capture (DAC)-reactive capture and conversion(RCC). In this study, we suggested and evaluated seven process systems comparing electrochemical and thermochemical reactive capture and conversion (RCC) with DAC. RCC analysis alone showed that current density, faradaic efficiency, and voltage are critical for electrochemical routes [4], while site ratio and the H₂/CO₂ ratio are key for thermochemical routes [5].

While RCC analysis highlights key factors within each method, integrating DAC into the system significantly shifts the priorities in the overall process design and economic considerations [6]. In contrast to our initial expectation, simulations show that the absorber's pressure ratio significantly influences overall CAPEX, not blower/compressor power. Optimizing this ratio could reduce integrated DAC-RCC system CAPEX by approximately 15% compared to non-optimized designs. Our preliminary life cycle assessment (LCA) indicates a potential trade-off between economic factors and environmental impact in the selection of RCC methods [7]. Specifically, while electrochemical RCC, particularly when coupled with renewable energy sources, shows promise for significant reductions in global warming impact, it tends to have a higher levelized cost of carbon monoxide (LCOC) compared to thermochemical RCC.

However, its levelized cost of carbon monoxide (LCOC) is estimated to be 1.2 to 1.5 times higher than thermochemical routes. This gap is primarily due to higher electrolyzer electricity demand. We anticipate future electrolyzer advancements, and lower renewable energy costs could improve electrochemical competitiveness. This research's novelty lies in its holistic analysis of integrated DAC-RCC systems. It reveals the critical influence of DAC operating parameters, especially the absorber pressure ratio, on overall system economics.

This differs from prior studies that predominantly treated DAC and downstream conversion as separate and independent units. Our findings offer crucial insights for the design and optimization of future carbon mitigation technologies, directly addressing atmospheric CO₂ accumulation. By evaluating both electrochemical and thermochemical routes within this integrated framework, we aim to provide more comprehensive solutions and a balanced perspective for sustainable carbon ma nagement.

References:

[1] Keith, D. W., Holmes, G., St. Angelo, D., & Heidel, K. (2018). A process for capturing CO₂ from the atmosphere. Joule, 2(8), 1573-1594. https://doi.org/10.1016/j.joule.2018.05.006

[2] McQueen, N., Gomes, K. V., Psarras, P., & Wilcox, J. (2021). A review of direct air capture (DAC): Scaling up commercial technologies and reducing costs. Progress in Energy, 3(3), 032001. https://doi.org/10.1088/2516-1083/abf835

[3] Kar, S., Sen, R., & Goeppert, A. (2021). Integrated CO₂ capture and conversion to fuels using dual functional materials: A review. Chemical Reviews, 121(13), 7949-7998. https://doi.org/10.1021/acs.chemrev.0c01175

[4] Jouny, M., Luc, W., & Jiao, F. (2018). General techno-economic analysis of CO₂ electrolysis systems. Industrial & Engineering Chemistry Research, 57(6), 2165-2177. https://doi.org/10.1021/acs.iecr.7b03514

[5] Veselovskaya, J. V., et al. (2022). Reactive capture of CO₂ from air using dual functional materials: Experimental and modeling insights. Energy & Fuels, 36(5), 2456-2465. https://doi.org/10.1021/acs.energyfuels.1c03982

[6] Somoza-Tornos, A., et al. (2021). Process modeling, techno-economic assessment, and life cycle assessment of the electrochemical reduction of CO₂: a review. iScience, 24(7), 102813. https://doi.org/10.1016/j.isci.2021.102813

[7] Lee, G., et al. (2023). Techno-economic analysis and life-cycle assessment of the electrochemical conversion process with captured CO₂ in an amine-based solvent. Sustainable Energy & Fuels, 7(5), 1234-1245. https://doi.org/10.1039/D2SE01567A