Oxidative coupling of methane over mixed metal oxide catalysts: Steady state multiplicity and catalyst durability

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2018-01, Vol.331, p.132-143
• Main Authors: Aseem, A., Jeba, Geofrey Goldwin, Conato, Marlon T., Rimer, Jeffrey D., Harold, Michael P.
• Format: Article
• Language: English
• Subjects: Deactivation; Hot spot; Methane; Oxidative coupling; Thermal effect
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2017.08.093

[Display omitted] •Thermokinetic steady-state multiplicity observed for mixed metal oxide catalysts.•Highest C2 yield (19%) obtained for Na2WO4-Mn/SiO2.•Doping of metal oxides significantly enhances catalyst stability.•Catalyst temperature rise up to 320°C observed.•Exothermic heat effects both promote reaction and cause deactivation. Exothermic heat effects are a crucial factor in determining the performance and stability of catalysts for the oxidative coupling of methane (OCM). Fixed bed temperature rise, steady state multiplicity, and catalyst durability are investigated over a range of feed conditions for the mixed metal oxides Cs/Sr/MgO, Cs/Ba/MgO, Cs/Sr/La2O3, and Na2WO4-Mn/SiO2. A comparison with previous studies on doped metal oxides catalysts for OCM clearly indicates that doping not only improves the performance but also significantly improves the catalyst stability. We experimentally demonstrate for the first time hysteresis behavior for Cs/Sr/La2O3 powder catalyst. Our results show that the catalyst stability depends on the magnitude of temperature rise in the catalyst bed. At a lower space velocity of 3,600cc/h/g, the catalysts exhibit moderate temperature rise (