Generalized Two Mode Dispersion Model of Convective Diffusion in Chemical Processes

Abstract

The axial dispersion model conventionally used for chemical process control is a coarse-grained model for the locally averaged concentration. For refinement of the dispersion model, two mode dispersion models have been proposed by incorporating specific local concentration distributions as the second mode. In this paper, we treated convective diffusion equations for multi-phase parallel laminar flow systems, and derived a generalized form of two mode dispersion equations by asymptotic analysis based on the projection operator technique. The generalized two mode model includes previous two mode models and can incorporate arbitrary second mode corresponding to practical applications. This method was applied to mass transfer analysis of two phase systems and shown to give asymptotic approximate solutions of transient phenomena. The generalized two mode model can be applied to the control of multi-phase chemical processes including microfluidic devices.