Non-isothermal inter-intraphase effectiveness factors for negative order kinetics—CO oxidation over Pt
✍ Scribed by Thomas Gordon Smith; Jindrich Zahradnik; James J. Carberry
- Publisher
- Elsevier Science
- Year
- 1975
- Tongue
- English
- Weight
- 412 KB
- Volume
- 30
- Category
- Article
- ISSN
- 0009-2509
No coin nor oath required. For personal study only.
✦ Synopsis
Non-isothermal catalytic effectiveness for negative order kinetics is studied numerically for various ratios of Bi,/Bi,, equal to and greater than unity. The specific case of carbon monoxide oxidation over supported Pt in a spherical catalyst is investigated for conditions of temperature and concentration of interest in automobile pollution abatement. Due to the phenomenon of increasing reaction rate with decreasing concentration associated with negative order kinetics, it is found that such catalytic systems tend to be self-amplifying with respect to reaction rate rather than self-limiting (as with positive order kinetics) thus rendering them sensitive to temperature increases across the gas boundary layer and within the catalyst itself. In particular, the use of realistic values of the flo parameters suggests that the temperature rise across the gas tilm is usually large. This, together with the increas, k" d thermal sensitivity, leads one to conclude that systems described by negative order kinetics should rarely be tregted without regard to thermal influences.