Analytical criteria for validity of pseudohomogeneous models of packed-bed catalytic reactors
- Univ. of Houston, TX (United States). Dept. of Chemical Engineering
- Dow Chemical Co., Freeport, TX (United States)
Pseudohomogeneous models are used extensively to simulate the behavior of packed-bed catalytic reactors. The use of highly active catalysts increases the importance of the transport resistances between the solid and the fluid, and hence, may invalidate the applicability of the pseudohomogeneous models. There exist criteria in the literature that predict when pseudohomogeneous models can be used to approximate the behavior of catalytic reactors. These criteria are derived by assuming that the predictions of pseudohomogeneous and the two-phase models differ only by a small amount and hence Taylor expansion can be used to quantify the difference between the two models. In this work, the authors show that the existing literature criteria may lead to erroneous conclusions and present new criteria that may be used to determine the regions of validity of pseudohomogeneous models. These criteria are very different from those in the literature and are derived from a rigorous analysis of the single-phase and two-phase models and comparison of their qualitative features (bifurcation diagrams). Application of the criterion to typical industrial situations show that they could differ from that of Mears by a factor of 10--10{sup 4}. It is also shown that the two-phase plug flow model has 10 qualitatively different types of bifurcation diagrams. Some of these contain high-temperature branches on which the solid temperature exceeds the adiabatic temperature rise.
- OSTI ID:
- 338582
- Journal Information:
- Industrial and Engineering Chemistry Research, Journal Name: Industrial and Engineering Chemistry Research Journal Issue: 3 Vol. 38; ISSN IECRED; ISSN 0888-5885
- Country of Publication:
- United States
- Language:
- English
Similar Records
Thermoflow multiplicity in a packed-bed reactor
Transient temperature excursions in adiabatic packed bed reactors. The pseudohomogeneous model