Transient response of catalyst bed temperature in the pulsed reaction of partial oxidation of methane to synthesis gas over supported rhodium and iridium catalysts
- Kansai Univ., Suita, Osaka (Japan)
- Osaka National Research Inst., Ikeda, Osaka (Japan)
Mechanisms of partial oxidation of methane were studied using a pulsed reaction technique and temperature jump measurement. Catalyst bed temperatures were directly measured by introducing a pulse of a mixture of methane and oxygen (2/1). With Ir/TiO{sub 2} catalyst, a sudden temperature increase at the front edge of the catalyst bed was observed upon introduction of the pulse, but the temperature of the rear end of the catalyst bed increased only slightly. The synthesis gas production basically proceeded via a two-step path consisting of highly exothermic methane complete oxidation to give H{sub 2}O and CO{sub 2}, followed by the endothermic reforming of methane with H{sub 2}O and CO{sub 2} over Ir/TiO{sub 2} catalyst. However, with Rh/TiO{sub 2} and Rh/Al{sub 2}O{sub 3} catalysts, the temperature at the front edge of the catalyst bed decreased upon introduction of the CH{sub 4}/O{sub 2} (2/1) pulse, and a small increase in the temperature at the rear end was observed. At first, endothermic decomposition of CH{sub 4} to H{sub 2} and deposited carbon or CH{sub x} probably took place at the front edge of the catalyst bed and then deposited carbon or generated CH{sub x} species would be oxidized into CO{sub x}. However, on Rh/SiO{sub 2}, synthesis gas was produced via a two-step path similar to the case of Ir/TiO{sub 2} catalyst. The reaction pathway of partial oxidation of methane with Rh-loaded catalysts depended strongly on the support materials.
- OSTI ID:
- 687748
- Journal Information:
- Journal of Catalysis, Journal Name: Journal of Catalysis Journal Issue: 2 Vol. 186; ISSN 0021-9517; ISSN JCTLA5
- Country of Publication:
- United States
- Language:
- English
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