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In this work, the role of hydrodynamics in an industrial-scale packed-bed catalytic reactor with a low tube/particle diameter ratio (dt/dp ∼ 3) and the role of redox dynamics of the catalyst surface together with the use of a catalyst activity profile are assessed on the heat transport during the partial oxidation of o-xylene on a V2O5/TiO2 catalyst. Temperature and concentration observations at different steady-state conditions are used to test the modeling approach, and reasonably good predictions are obtained when (1) the information contained in the heat-transport parameters, estimated from a boundary layer approximation to the hydrodynamics in the absence of chemical reactions [Ind. Eng. Chem. Res. 2007, 46 (23), 7426−7435], is used in the reactor model and (2) the redox catalyst dynamics, included in the reaction kinetics, is used, together with an empirical catalyst activity profile.

This work describes a heat-transfer study conducted in two beds of low tube/particle diameter ratio (dt/dp ≈ 3) with almost the same diameter but different lengths, packed with catalyst spheres, operating in quasi-adiabatic and nonadiabatic modes. The operation in the short bed in a quasi-adiabatic mode provided independent sets of experiments to estimate the effective thermal conductivity at various Reynolds numbers. This information was transferred successfully to model the short and long beds operating in a nonadiabatic mode. The modeling compares the classical approach to model heat transfer in a packed bed with no hydrodynamics, against those which include the hydrodynamics and a radial voidage profile, as well as the boundary layer approximation of this model. Modeling results showed that very similar predictions of radial and axial temperature profiles are obtained in all cases, making it difficult to discriminate between both model approaches.