| Autor: |
Karim, Hasan, Pfefferle, Lisa D., Markatou, Penelope, Smooke, Mitchell |
| Zdroj: |
Symposium (International) on Combustion; January 1994, Vol. 25 Issue: 1 p299-306, 8p |
| Abstrakt: |
The effect of boundary-layer flow and heterogeneous/homogeneous reaction chemistry in determiningproduct selectivity for catalytically promoted oxidation of ultralean CH3Cl over a Mn-based catalyst was investigated numerically. This work has relevance to modeling of more general catalytic combustion systems in defining the importance of transport and chemistry interactions. In this study, we find that the presence of Mn-based catalyst can significantly decrease the temperature necessary to achieve a given conversion of CH3Cl. The numerical study of the experiment used plug-flow, lumped-parameter transport, and laminar-flow models with detailed gas-phase chemistry. These flow models coupled with gas-phase reaction mechanisms from the literature and an experimentally determined surface reaction rate were used to illustrate heterogeneous/homogeneous reaction coupling and how it is influenced by transport. Kinetic modeling shows that the heterogeneous and homogeneous interaction occurs through CH3Cl decomposition on the surface that initiates gas-phase reaction. For the slower velocity, there is small difference in plug-flow model and detailed laminar boundary-layer model predictions. The difference in prediction between flow models becomes larger at the high velocity, with shorter residence time, where the higher surface temperature needed for equivalent conversion causes surface reaction products to be converted before they can be transported to the bulk. The important parameter for modeling heterogeneous/homogeneous interactions is the Damköhler number with respect to gas-phase consumption of species produced by surface reaction. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
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