Dynamics of a three-phase upflow fixed-bed catalytic reactor

A dynamic model of an upflow fixed-bed catalytic reactor :is developed to e xamine numerically transient axial temperature and concentration profiles o btained for the consecutive hydrogenation of 1,5,9-cyclododecatriene on a P d/Al2O3 catalyst, This non-isothermal heterogeneous model includes the resi stances to heat and mass transfer at the gas-liquid and liquid-solid interf aces, as well as the heat exchange through the jacket of the reactor. The p redictions of the model are compared to experimental data for various gas a nd liquid flow rates to describe dynamic events, such as the start-up of th e reactor and the effects of sudden changes in the operating conditions on the reactor behaviour and its thermal stability. The predicted transient pr ofiles are in good agreement with the experimental measurements. Still, the dynamic model is not able to correctly predict hot spots and runways exper imentally observed at very high hydrogen flow rates. (C) 1999 Elsevier Scie nce Ltd. All rights reserved.