Oxidative Dehydrogenation of Ethane: Molten Salt Promoted Catalyst with Passive Carbon Capture

Ethylene is a valuable chemical that serves as an important component in many compounds and products such as polyethylene, polyvinyl chloride (PVC) and has various other applications. Ethylene is industrially produced from the dehydrogenation of ethane. Ethane is a significant product from petroleum refinement and other natural gas refinements. The current implemented method of converting ethane to ethylene, steam cracking, requires separate fuel to maintain high operating temperatures resulting in high COx (CO and CO2) yields, periodic shutdowns and the ethylene yield is limited to thermodynamic equilibrium. Our goal was to produce high ethylene and low COx conversion through a chemical looping, catalyst-promoted process while capturing CO2 with a molten salt promoter. The composite catalysts used were various mol combinations of La_O.9-SrO_0.2-FeO₃ (LSF) which were synthesized through reactive grinding. The catalysts were impregnated with various mol combinations of a molten carbonate salt mixture consisting of LiCO₃-Na₂CO₃-K₂CO₃. The carbonate-perovskite catalysts were run at 800℃ with a total gas hourly space velocity of 150 h^-1. The chemical looping process consisted of a reduction phase (ethane and argon with ~20% ethane), an argon purge, a reoxidation using a flue gas stimulant, followed by another argon purge. Our initial results indicated moderate ethylene yields with low COx selectivity. However, more catalysts still need to be tested to see if chemical looping dehydrogenation is efficient enough to overcome steam cracking.