Modelling of hydrodesulfurization catalysts: II. Effects of catalyst pore structures on deactivation by metal deposits

A mathematical model, previously developed to describe deactivation by metal deposition, has been applied to catalyst with macro-, micro- and random pore structures. Simulation results showed that effectiveness factor reduces progressively with the increasing age of the catalyst. For the macropore system, catalyst lifetime was found to be over 1 year and it is the highest in comparison with both micropore and random pore models. It was revealed that a pore structure in which the pore diameter is enlarged increases hydrodemetallization activity and will be very effective for improving metal resistance because pore-mouth plugging can be curtailed. Predicted catalyst lifetimes matched plant data very closely. The need to develop catalysts of optimum pore structure to achieve desirable goals has been validated.