Mathematical modeling of internal mass transport limitations in methanol synthesis

Several simplifications on the dusty gas model were analyzed with respect t o the accuracy of the resulting mathematical models in describing the effec ts of internal mass transport limitations in methanol synthesis. It turned out that all the models, including the simplest one, viz. Thiele modulus co ncept using pseudo-first-order kinetics, are capable to predict the methano l and water effectiveness factors with a sufficient accuracy. Therefore, ap plication of the simplest Thiele modulus concept is advised, since this mod el is easily incorporated in complex methanol synthesis reactor models. Mor eover, we expect that the Thiele modulus approach can be applied for other complex reaction/diffusion systems, provided that proper linearization of t he kinetic model is possible. The experimental data of Seyfert and Luft (19 85) on the rate of methanol production for different catalyst sizes can be described with the kinetic expressions of Graaf et al. (1988,1990): using t he mathematical mass transport models presented in this paper. (C) 2000 Els evier Science Ltd. All rights reserved.