Partial wetting of cylindrical catalytic carriers in trickle-bed reactors

The use of a modified Thiele modulus, as a correlating parameter for partially wetted catalyst pellets, is compared with the exact solution of the diffusion and reaction problem. The study of a variety of partially wetted cylindrical catalyst pellets for first‐ and second‐order kinetics indicates that the manner in which particles are externally wetted does not significantly influence the value of the effectiveness factor. External and internal partial wetting of industrial‐size porous extrudates is determined in a bench‐scale hydrotreater at real hydroprocessing conditions by simulating the system response to a step change of feed using the sulfur compounds of a petroleum fraction as tracer molecules. To solve the corresponding mass balances in the interparticle and intraparticle domain, two different numerical methods are compared.