MODELING MULTITUBULAR CATALYTIC REACTORS - THE INFLUENCE OF SHELL SIDE FLOW

The main purpose of the paper is to highlight some important features of modelling multitubular catalytic reactors. In this study a two dimensional model is used to describe the flow of the coolant on the shell side. The unit is divided in cells over the cross section of the assembly as well as in the axial direction. With this approach the coolant flow is made up of two different streams: one in pure crossflow perpendicular to the tubes and the other in parallel to the bundle. The performance of the tubes in each cell is computed with a two dimensional heterogeneous model and has shown to be sensitive to the number of cells used, particularly in the baffle window zones that are critical areas and therefore require a large number of cells. The influence of the operating conditions upon production and yield for the co-current and counter-current coolant flow regimes is examined and it is shown that carrying out the analysis on a single tube basis is not adequate to predict the optimum operating conditions.