Transient diffusion of heat, mass species and momentum in cylindrical pellets during catalytic oxidation of CO
✍ Scribed by C.B. Benham; V.E. Denny
- Publisher
- Elsevier Science
- Year
- 1972
- Tongue
- English
- Weight
- 964 KB
- Volume
- 27
- Category
- Article
- ISSN
- 0009-2509
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✦ Synopsis
Transient diffusion of heat, mass species, and momentum in cylindrical pellets during catalytic oxidation of CO is investigated. Experimental measurements of intrapellet temperature distributions are reported for CuO-AI2Oz pellets, 0-25 in. dia., which are subjected to cross-flow of binary mixtures of CO and 02, the pellets initially being saturated with pure oxygen. Mole fraction CO and temperature in the free stream ranged from 0.026 to 0.105 and 70 to 200°C, respectively. The Reynolds number based on pellet diameter ranged from 25 to 110. The effects of pellet porosity and copper content were also investigated. Of particular interest is the asymmetric nature of the problem wherein angular variations in free surface transfer rates result in markedly non-isothermal and nonsymmetric pellet characteristics.
Further insight into the temporal behavior of the intrapeilet problem is extracted from an analysis of unsteady diffusion processes in porous media, using the dusty gas model to formulate mass species and energy fluxes. A quasi-one-dimensional approximation of the problem is solved numerically. Preliminary results indicate that a simple first-order representation of the kinetics as inferred from static experiments is inadequate for predicting the experimental transient behavior of a catalyst pellet.