Three-phase mass transfer: One-dimensional heterogeneous model

Abstract

A new one-dimensional heterogeneous model has been developed to describe the mass transfer rate for a three-phase system which contains larger particles, i.e. particles larger than or in the same order of magnitude as the gas-liquid boundary layer. The diffusion of the absorbed component into the bulk phase can occur through a composite medium—it can be a continuous + a dispersed phase ( δ 1 + d > δ) or a continuous + a dispersed + a continuous phase ( δ 1 + d < δ)—or through the continuous phase, only. The mass transport through the heterogeneous medium has been solved using the film-penetration theory. For the sake of simplicity, the spherical particles are assumed to be cubic ones in the boundary layer. The model also takes into account the effects of the first- and zero-order reactions which can take place either in the continuous or in the dispersed phase. The effect of reaction and particle size on the enhancement of absorption rate has been discussed. In addition, the role of the boundary conditions and that of the bulk phase concentration (in brief) has been shown (or analysed).