12 - Influence of liquid-continuous impinging streams on process kinetics

Abstract

This chapter illustrates the influence of liquid-continuous impinging streams (LIS) on process kinetics. The existence of pressure fluctuation and the promotion of micromixing are the major features of liquid-continuous impinging streams. One of their valuable applications is the promotion of process kinetics. Strong micromixing and pressure fluctuation promote process kinetics by the mechanisms of increasing both the probability of collision and the effective collisions. Process kinetics not only depends on the nature of the substance system involved and the operating conditions but also relates to the flow configuration in the processing device employed. Comparative investigations were made for the crystal-growth kinetics of di-sodium phosphate in the impinging stream crystallizer (ISC) and the fluidized bed crystallizer (FBC), and the kinetics of ethyl acetate saponification in the submerged circulative impinging stream reactor (SCISR) and the stirred tank reactor (STR). Results suggest that the major reasons of LIS promoting process kinetics may be that the effective micromixing increases the collision probability between molecules and that the considerably strong pressure fluctuation changes the energy distribution over the molecules, causing the part of the molecules that obtains more energy to achieve the higher level required for inducing reaction.