Ethane catalytic partial oxidation to ethylene with sulphur and hydrogen addition over Rh and Pt honeycombs

• Sulphur poisoning can enhance ethylene formation during CPO of C2H6 over Pt and Rh.
• Selective S-poisoning of catalytic reactions enables to probe their contribution.
• Ethylene is mainly formed by gas phase oxidative dehydrogenation.
• Sulphur selectively inhibits undesired steam reforming of ethane/ethylene on Rh.
• S-poisoning enhances beneficial effects of sacrificial H2 addition on C2H4 yield.

The catalytic partial oxidation of ethane to ethylene was investigated over Rh and Pt based honeycomb reactors with the addition of sulphur to the feed (up to 51 ppmv as SO2). Transient and steady state ethane CPO tests were run at C2H6/O2 = 2 under self-sustained high temperature, short contact time conditions, and the impact of sulphur poisoning was also studied during operation of the reactor with H2 co-fed as a sacrificial fuel.An attempt was made to shed light on the complex interaction of hetero-homogeneous reaction paths available in a C2H6 CPO reactor, by comparing two catalysts showing markedly different activities, and by taking advantage of the selective poisoning effect of sulphur to probe the contribution of some heterogeneous reactions to the overall reactor performance. CPO process selectivity and yield to ethylene were enhanced by the selective S-poisoning of catalytic steam reforming of C2H6 and C2H4 over Rh, as well as by the inhibition of C2H6 catalytic oxidation when H2 was co-fed as sacrificial fuel over both Rh and Pt catalysts.

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