External mass and heat transfer limitations of the partial oxidation of methane over a Pt/MgO catalyst -- Consequences for adiabatic reactor operation
- Ruhr-Univ. Bochum (Germany). Lehrstuhl fuer Technische Chemie
A kinetic model for the partial oxidation of methane to syngas over a highly active Pt/MgO catalyst was developed using hyperbolic rate equations. The formation of syngas was derived to occur via primary methane combustion to CO{sub 2} and H{sub 2}O and secondary steam and CO{sub 2} reforming of methane to CO and H{sub 2}. On the basis of this kinetic model the performance of an adiabatic reactor was simulated. A sensitivity analysis with respect to radiation and heat conductivity of the catalyst bed on axial temperature and concentration profiles was performed assuming T{sub inlet} = 873 K and U{sub reactor,873K} = 3 m/s. A hot-spot temperature on the surface of ca. 1,700 K and at 1 bar and 2,600 K at 25 bar and large gradients between surface and gas-phase temperature were calculated. No significant contribution of radiation to the heat transfer was predicted. The effective heat conductivity of the catalyst bed is an important factor to decrease hot-spot temperatures. The maximum temperature amounts to 1,380 K (1 bar) and 2,100 K (25 bar), assuming a heat conductivity of the catalyst bed of 0.15 J/s.m.K. Equilibrium conversion and selectivity is obtained with a bed of less than 1 mm length.
- OSTI ID:
- 536422
- Journal Information:
- Industrial and Engineering Chemistry Research, Vol. 36, Issue 8; Other Information: PBD: Aug 1997
- Country of Publication:
- United States
- Language:
- English
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