ACCOUNTING FOR RADIAL GRADIENTS IN THE MODELLING OF PACKED BED TUBULAR REACTORS.

This study is concerned with the steady state modelling of a packed-bed non-adiabatic reactor with radial temperature and concentration gradients. The effect of the choice of the collocation point and of the order of the collocation in the radial direction is studied for the steady state case. The two main aspects investigated are the effects of the collocation order on the predicted axial temperature profile and on the exit product concentrations. A comparison is also made with reactor models based only on average temperature and concentration profiles. The pilot scale reactor used for this study has heat transfer at the walls, and the catalyzed butane hydrogenolysis system is a highly exothermic set of series-parallel reactions. The reactor operation is characterized by radial temperature gradients and an axial hot spot.