(701c) Evaluating the Economic Feasibility of Valorizing Lignocellulosic Biomass through Electrochemical Hydrogenation (Invited)

The rapidly decreasing cost of wind and solar electricity generation coupled with growing global concern regarding climate change are motivating the decarbonization and electrification of the world’s industries [1,2]. Energy-efficient electrochemical processes, which leverage carbon-neutral or carbon-negative power sources, have the potential to increase the sustainability of chemical manufacturing as well as to open new synthetic routes through unique molecular reactivities [3,4]. Of particular relevance is the ongoing transition from fossil-based to biomass-based feedstocks, a necessary step towards green chemical production, which challenges traditional manufacturing approaches due to increased oxygen content in biomass sources as well as the mismatch in the location of resources and processing facilities [5,6]. Electrochemical approaches are more amenable to distributed production as they operate near ambient conditions and utilize broadly accessible electricity. Hydrogenation is a relatively simple but key transformation for valorizing chemical compounds, underlying many important industrial processes. While thermochemical hydrogenation processes have been extensively studied, the technical and economic aspects of electrocatalytic hydrogenation (ECH) processes are less well-understood.

This talk presents a framework for evaluating the economic feasibility of ECH processes that follow simple, yet generalizable electrochemical pathways involving the parallel faradaic reactions that generate desirable and undesirable products. Annualized costs present a simplified economic metric that allows for direct calculation of a minimum selling price for a desired product, while simultaneously allowing detailed descriptions of the existing technological tradeoffs. This framework is validated against the U.S. Department of Energy targets for hydrogen production from water electrolysis to ensure accuracy of both overall model results and estimated component contributions [7]. As a commonly found moiety in lignin-based compounds and a valuable commodity chemical respectively, guaiacol hydrogenolysis to phenol is chosen as a platform from which to present sensitivity of the system cost to materials properties. More generally, this work aims to identify component performance targets for cost-competitive ECH, to highlight key technical challenges, and to inform future research directions. These materials targets were then tested for feasibility in a continuous electrolysis cell to establish experimental understanding of the research challenges.

References

[1] Z.J. Schiffer, K. Manthiram, Electrification and Decarbonization of the Chemical Industry, Joule. 1 (2017) 10–14. doi:10.1016/j.joule.2017.07.008.

[2] J. Deutch, Decoupling Economic Growth and Carbon Emissions, Joule. 1 (2017) 3–5. doi:10.1016/j.joule.2017.08.011.

[3] D. Pletcher, F.C. Walsh, Organic electrosynthesis, in: Ind. Electrochem., Springer, 1993: pp. 294–330. http://link.springer.com/content/pdf/10.1007/978-94-011-2154-5_6.pdf (accessed August 20, 2015).

[4] M. Yan, Y. Kawamata, P.S. Baran, Synthetic Organic Electrochemical Methods Since 2000: On the Verge of a Renaissance, Chem. Rev. (2017). doi:10.1021/acs.chemrev.7b00397.

[5] R. Rinaldi, F. Schüth, Design of solid catalysts for the conversion of biomass, Energy Environ. Sci. 2 (2009) 610–626. doi:10.1039/B902668A.

[6] P.N.R. Vennestrøm, C.M. Osmundsen, C.H. Christensen, E. Taarning, Beyond Petrochemicals: The Renewable Chemicals Industry, Angew. Chem. Int. Ed. 50 (2011) 10502–10509. doi:10.1002/anie.201102117.

[7] C. Ainscough, D. Peterson, E. Miller, S. Satyapal, DOE Hydrogen and Fuel Cells Program Record, U.S. Department of Energy, 2014.