Oxidative dehydrogenation of ethane over supported chromium oxide and Pt modified chromium oxide Original Research Article

The oxidative dehydrogenation of ethane at very short contact times was studied using Cr2O3 and Pt-modified Cr2O3-coated ceramic foam monoliths and Cr2O3/Al2O3 pellet catalysts. C2H4 selectivity and C2H6 conversion increased over the Cr2O3 catalysts compared to Pt-coated monoliths. The 10 wt.% Cr2O3/ZrO2 monolith catalyst produced the best results of all catalysts examined. With the Cr2O3/ZrO2 monolith, C2H4 selectivities of 70% could be obtained at a C2H6 conversion of about 80% compared to a C2H4 selectivity of 65% and 75% C2H6 conversion under the same conditions over the Pt/α-Al2O3 monolith catalyst. However, in contrast to the Pt catalyst, several Cr2O3 catalysts displayed a limited lifetime. The lifetime of the Cr2O3 catalyst depends on the C2H6/O2 feed ratio, the support material, the weight loading of the catalyst, the flowrate, the amount of N2 dilution, and the preheat of the feed. The 10 wt.% Cr2O3/ZrO2 monolith catalyst showed no deactivation up to a C2H6/O2 ratio of 2.4 with 20% N2 dilution at a flowrate of 2 SLPM when Cr2O3/α-Al2O3 and lower weight loading of Cr2O3 on ZrO2 extinguished at a C2H6/O2 ratio of 1.8 and showed superior alkene yield when compared to the Pt/α-Al2O3 catalyst under the same conditions.