A MODEL FOR THE OXIDATION OF SULFUR-DIOXIDE IN A TRICKLE-BED REACTOR

A reaction rate model based on complete wetting of the catalyst partic les in a trickle-bed reactor is presented. It is considered that the p endular rings are formed at the contact points of the particles and th e liquid flows down as thin films on the remaining surface between the pendular rings. Assuming that the flow in the films is laminar, the l iquid in the pendular rings is well-mixed, and a fraction of the liqui d flowing in the films bypasses the pendular rings, the reaction rate was found. The data obtained for oxidation of sulfur dioxide on activa ted carbon were used to test the model predictions of the dependence o f reaction rate on liquid velocity. The reaction rates in nonprewetted beds were found to be lower than those in prewetted beds. The propose d model correlated the observed reaction rates satisfactorily, with th e fractional thickness of the film that bypasses the pendular ring as an adjustable parameter. The model also predicted the reaction rate tr ends, including the minimum of the oxidation rate reported by Mata and Smith (Chem. Eng. J. 1981, 22, 229-235).