Research Theme #3: Design non-traditional electrochemical processes (e-chemical) that intensify the sustainability of the chemical industry.

Major CO2-emitting sources are fossil fuel-based power plants and industrial facilities, in which the government, industry, and academia are highly interested in introducing carbon-neutral processes[i]. In the case of power plants, renewable energy and a society that relies on hydrogen energy technologies will help to escape from a dependence on fossil fuels. However, the supply of chemicals such as syngas, alcohol, and ethylene, which can be used as reagents to generate plastics and transportation fuels, is difficult to meet the global demand without fossil fuel-based petrochemical processes. Therefore, the electrochemical carbon dioxide reduction reaction (CO2RR) has emerged as a promising technology to close the anthropogenic carbon cycle by producing clean chemicals (especially petrochemical precursors such as ethylene) from renewable energy.

The main criticisms of commercializing CO2RR processes are beginning to be shouldered by 1) its nonproductive paired oxidation reaction: oxygen evolution reaction (OER) regarding valueless oxygen gas and high oxidative potential, and 2) lack of systematic achievement of optimal process design in terms of economics, separation, transportation, and scale-up[ii]. Therefore, my research group will systematically design a general electrochemical processes (e-chemical)—coupling CO2RR and organic oxidation reactions (OORs) to produce value-added products and substituting thermal-based separation (e.g. distillation) to ultrasound separation technology—to secure both significant economic feasibility and sustainability. Interestingly, research theme #3 will be the key to achieve the ultimate long-term goal by verifying the performance of multiscale methodology (theme #1) and autonomous design discovery (theme #2) via actual process design and operation.

To illustrate coupling the CO2RR with the value-added OOR, the oxidation of biomass-derived 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA)—renewable building block of polyethylene furanoate (PEF) that can substitute for polyethylene terephthalate (PET)—can be implemented as an anode reaction with lower overpotential. My recent technoeconomic analysis (TEA) highlights the promise that CO2RR-OOR processes can secure significant economics even compared with current market prices8. Unlike petrochemical processes, sustainability and eco-friendliness are also secured. Therefore, my research group intends to design the piping and instrumentation diagram (P&ID)-level detail design of e-chemical processes.

In particular, liquid products should be separated from electrolyte using distillation, which accounts for 95% of the energy used in the chemical process industry[iii], 45-55% of the total energy, and 10-15% of the US energy consumption[iv]. We will substitute distillation separation using the ultrasound separation process—regardless of the azeotropic point to produce high purity bioethanol production[v]—to reduce at least 40% of energy. Moreover, it can be operated by electrical energy from renewable energy so that fully electrical energy-based clean chemical production process can be realized by coupling with CO2RR-OOR processes. The impact of our work and actual large-scale demonstration in the research theme #3 will boost the technology investment under the belief that this is where we must go forward.[vi] What if “Space Age” comes true that humanity migrates to Mars? We believe that onsite chemical productions will be realized with this technology!

[i] Bui, M., Adjiman, C. S., Bardow, A., Anthony, E. J., Boston, A., Brown, S., … & Hallett, J. P. (2018). Carbon capture and storage (CCS): the way forward. Energy & Environmental Science11(5), 1062-1176.

[ii] De Luna, P., Hahn, C., Higgins, D., Jaffer, S. A., Jaramillo, T. F., & Sargent, E. H. (2019). What would it take for renewably powered electrosynthesis to displace petrochemical processes?. Science364(6438), eaav3506.

[iii] U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Industrial Technology Program. (2005). Hybrid separations/distillation technology: research opportunities for energy and emissions reduction

[iv] Ritter, S.K. (2017). Taking the heat off distillation. Chemical & Engineering News, June 19, 2017.

[v] Kirpalani, D. M., & Toll, F. (2002). Revealing the physicochemical mechanism for ultrasonic separation of alcohol–water mixtures. The Journal of chemical physics, 117(8), 3874-3877.

[vi] Bushuyev, O. S., De Luna, P., Dinh, C. T., Tao, L., Saur, G., van de Lagemaat, J., … & Sargent, E. H. (2018). What should we make with CO2 and how can we make it?. Joule2(5), 825-832.

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