Diffusional Kinetics of Catalytic Vapor-Phase Reversible Reactions with Decreasing Total Number of Moles


Many industrial processes like ammonia and methanol syntheses, SO//2 oxidation and vapor-phase hydrogenations, involve the decrease in the total number of moles, which creates an inward flow in the pores of the catalyst. For the product to be able to diffuse against this flow, high concentration gradient is needed; otherwise, the rate of process slows down. This equilibrium conditions can be reached inside the pores, while under the bulk gas conditions outside the pores, the system is far from equilibrium limitations. This is the reason why diffusional limitations can be experimentally observed under certain conditions where the Weisz-Prater criteria would predict none. The phenomenon was mathematically modeled and digitally simulated for a case of multiple reactions under non-isothermal conditions.

Meeting Name

The Eighth International Symposium on Chemical Reaction Engineering


Chemical and Biochemical Engineering

Keywords and Phrases

Catalysis-mathematical Models; Catalysts-performance; Chemical Engineering-computer Simulation; Chemical Equipment-reactors; Gases-diffusion

Document Type

Article - Conference proceedings

Document Version


File Type





© 1984 Institution of Chemical Engineers (IChemE), All rights reserved.

Publication Date

01 Jan 1984

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