(13b) Electrocatalyst Development for Electrochemical Oxidative Dehydrogenation of Ethane

With the development of unconventional resources, there will be an anticipated increase in natural gas production [1]. An increase in natural gas production incentivizes the development of methods to handle natural gas liquids, the hydrocarbon compounds in natural gas that are heavier than methane, such as ethane [2]. Contemporary natural gas liquid processing methods focus on producing or transporting the methane component of natural gas at significant economic and energy investment [3]. Work at Ohio University’s Institute for Sustainable Energy and the Environment, supported by the U.S. Department of Energy’s National Energy Technology Laboratory [DE-FE0031709], focuses on upgrading ethane by means of an electrocatalytic solid oxide fuel cell system that performs electrochemical oxidative dehydrogenation (e-ODH) to ethylene [4,5]. Under this project the team has synthesized and evaluated perovskite electrocatalysts to conduct e-ODH. Promising electrocatalyst compositions identified through this effort can be incorporated into the proposed modular processing technology that would enable economical ethane separation and upgrading.

Perovskite electrocatalysts were synthesized within a porous yttria-stabilized zirconia (YSZ) scaffold via infiltration, serving as the e-ODH anode of a solid electrolyte fuel cell using lanthanum strontium manganite (LSM20) as an oxygen reducing cathode electrocatalyst. The infiltrated anode electrocatalysts were characterized with scanning electron microscopy and X-ray diffraction. The ethane oxidation is catalyzed on the porous scaffold anode while the oxygen reduction occurs on the cathode, following the reaction chemistry shown below.

Anode: C₂H₆ + O^2- → C₂H₄ + H₂O + 2e^-

Cathode: 1/2O₂ + 2e^- → O^2-

Overall ODH: C₂H₆ + 1/2O₂ → C₂H₄ + H₂O

The infiltrated electrocatalysts’ e-ODH capabilities were evaluated through electrochemical testing of the solid oxide fuel cell and quantitative gas chromatography analysis of the product gases under galvanostatic conditions.

This work has demonstrated the suitability of the electrocatalyst synthesis techniques and the favorability for ethylene selectivity over certain electrocatalyst compositions that will be presented in this talk. More broadly, this project has elucidated the influence of catalyst material upon ethane e-ODH chemistry and showed potential feasibility for incorporation into the modular design. In this talk electrocatalyst material characterization and fuel cell test results will be presented.

1. MacIntyre, S. U.S. Energy Information Administration: U.S. ethane production, consumption, and exports expected to increase through 2018, posted January 17, 2017. https://www.eia.gov/todayinenergy/detail.php?id=29572 (accessed October 31, 2020).
2. U.S. Energy Information Administration: What are natural gas liquids and how are they used?, posted April 20, 2012. https://www.eia.gov/todayinenergy/detail.php?id=5930 (accessed April 9, 2021).
3. Miller, T.; Beck, D. Gas Processing & LNG: Maximize propane recovery and ethane rejection at cryogenic gas plants. http://gasprocessingnews.com/features/201612/maximize-propane-recovery-a... (accessed October 31, 2020).
4. Daramola, D.A.; Velraj, S.; Trembly, J. Electrochemical Oxidative Dehydration (e-ODH) As a Process Intensification Platform in Shale Gas Upgrading. In 2019 AIChE Annual Meeting; Orlando, FL, November 10-15, 2019.
5. Kasick, A.; Hajer, A.A.; Daramola, D.A.; Velraj, S.; Trembly, J. Advances in the Use of Electrochemical Oxidative Dehydrogenation to Convert Natural Gas Liquids to Value Added Chemicals. In 2020 AIChE Annual Meeting; San Francisco, CA, November 16-20, 2020.