(513cd) A Data Driven Investigation of Catalytic Upgrading of Ethane to Ethylene over Ga/Al2O3

The recent shale gas revolution offers exciting opportunities to meet global demands with new solutions. Increasing demand for ethylene, one of the world’s most produced chemicals, presents such an opportunity. While traditionally generated through naphtha cracking, ethylene may also be produced through the dehydrogenation of ethane present in shale gas. To enable the economic feasibility of this process, studies¹ screened numerous candidate catalysts and discovered alumina-supported gallium (Ga/Al₂O₃) as a highly promising material. However, its impressive catalytic activity is inhibited by deactivation due to coking. Attempting to prevent this deactivation while retaining dehydrogenation activity, multiple investigations^2,3 explored coking mitigation strategies, such as CO₂ co-feeding, but we have yet to understand the complete, underlying kinetics and unlock the potential of this exciting catalyst.

In this work, we investigate the kinetics of ethane dehydrogenation over Ga/Al₂O₃ and the associated deactivation. Analyzing our micro gas chromatography data with novel Bayesian techniques, we ascertain a layered reaction network and associated kinetic parameters. We discover a fundamental change stemming from the water produced that selectively affects ethane dehydrogenation but not the unwanted side reaction of hydrogenolysis. This water effect also applies to the deactivation kinetics and explains CO₂ co-feeding inhibiting coking through the surprising lens of the reverse water-gas shift reaction. Applying these findings alongside additional experiments exploring water co-feeding, we identify a promising path towards substantial conversion, improved selectivity, and negligible coking. These discoveries offer novel insights into this promising catalyst and general applicability to similar oxide materials.

1. Nakagawa, K., et al. Chemical Communications, no. 9 (1998): 1025–1026.
2. Xu, B.,et al. Journal of Catalysis, no. 2 (2006): 470–477.
3. Xiao, H., et al. Catal. Sci. Technol., no. 13 (2016): 5183–5195.