Determination of the Minimum Catalyst Amount in the Design of Catalytic Distillation Columns

This paper presents a method to determine the minimum amount of a catalyst needed to operate a heterogeneously catalyzed reactive distillation column based on kinetic and VLE data only, avoiding rigorous column simulations. Good initial estimates for catalyst loadings are rarely discussed, and shortcut methods are lacking. The described method determines the highest possible reaction rate using known kinetics and column stage temperatures obtained from ternary diagrams of the column top and bottom sections, neglecting the highest or lowest boiler of the column, respectively. The method was validated against several literature cases. From these cases, it could be determined that a conservative estimate for the amount of the catalyst in the early design phase is six times the minimum catalyst found using the method described. Additionally, the presented method provides information regarding the operability of the column, for example, related to catalyst deactivation.