Valorization of Lower Alkanes via Selective Oxidative Dehydrogenation
Ethane catalytic oxidative dehydrogenation (ethane ODH) is an attractive alternative method to directly produce ethylene from ethane minimizing the important environmental and economic restrains associated with the conventional steam cracking method. The key for a successful industrial implementation of this process is the innovative integration of both catalyst and process advances. Optimum catalyst design includes characterization of the catalyst active site and investigation of the reaction mechanism via advanced isotopic techniques and detailed mechanistic studies. On the other hand, operating conditions, reactor type and reactants contact mode have been identified as critical actors for ethane oxidative dehydrogenation. The above aspects are investigated over NiO-based mixed oxides, a class of promising catalytic systems for ethane ODH.
- Doping NiO with higher valence cations results to enhanced catalytic performance;
- 85Nb0.15 catalyst presents over 40% ethylene yield at 400oC, a performance (per pass yield) competing the conventional steam cracking process;
- Advanced isotopic studies confirmed that ethane ODH over NiO-based catalysts occurs via a Mars van Krevelen type mechanism;
- Experimental and computational studies allowed comparison between different reactor configurations (reactor type, reactants contact mode, etc.) in order to maximize ethylene yield.
Scheme 1: Proposed reaction mechanism for ethane ODH over NiO-based catalysts
(Z. Skoufa, E.Heracleous, A.A. Lemonidou, J. Catal 322 (2015) 118-129)