Modelling of gas-liquid reactors - implementation of the penetration modelin dynamic modelling of gas-liquid processes with the presence of a liquidbulk

Analytical solution of models for gas-liquid reactors is restricted to a fe w asymptotic cases, while most numerical models make use of the physically less realistic stagnant film model. A model was developed that simulates th e dynamic behaviour of gas-liquid tank reactors by simultaneously solving t he Higbie penetration model for the phenomenon of mass transfer accompanied by chemical reaction and the dynamic gas and liquid phase component balanc es. The model makes it possible to implement an alternative for the well kn own Hinterland concept, which is usually used together with the stagnant fi lm model. In contrast to many other numerical and analytical models the pre sent model can be used for a wide range of conditions, the entire range of Hatta numbers, (semi-)batch reactors, multiple complex reactions and equili brium reactions, components with different diffusion coefficients and also for systems with more than one gas phase component. By comparing the model results with analytical asymptotic solutions it was concluded that the mode l predicts the dynamic behaviour of the reactor satisfactorily. It is shown that under some circumstances substantial differences exist between the ex act numerical and existing approximate results. It is also shown that for s ome special cases, differences can exist between the results obtained using the stagnant film model with Hinterland concept and the implementation of the Higbie penetration model. (C) 2000 Elsevier Science S.A. All rights res erved.