Modelling of three-phase sparged reactor: non-uniform solid concentration profile

Abstract

Models have been developed in order to obtain the non-uniform concentration profiles and the exit age distribution of the solid phase in three-phase sparged reactors. The constant-size particles as well as the dissolving particles have been considered. Procedures have been developed for the estimation of solid-phase residence time even though the net particle velocity is in the backward direction. The effects of superficial liquid velocity, particle size and solid-phase dispersion coefficient on solid-phase residence time have been investigated. Using the exit age distribution and the conversion-time relationships for single particles, performance charts have been constructed for when the rate-controlling step is associated with the solid phase. Several reaction mechanisms have been considered for the construction of performance charts. It has been shown that the design of reactor outlet is very important and governs the solid-phase concentration profile within the reactor. An attempt has been made to propose a theoretical boundary condition at the reactor outlet for a non-uniform solid concentration profile of constant-size particles. The relationship between the design of the outlet and the concentration jump at the outlet has been analysed.