A new approach for the column apparatuses modeling in chemical and power engineering

Abstract

The column apparatuses are main devices for solution of technological and ecological problems in chemical and power engineering. A new approach of the column apparatuses modeling on the base of the physical approximations of the mechanics of continua, using two steps models: convection-diffusion type of model (for qualitative analysis) and average concentration model (for quantitative analysis), is presented. The convection-diffusion type of models describe chemical and mass transfer processes in column apparatuses in the cases of one, two ore three phases systems, where the solid phase is reagent, catalytic or packed bad. A qualitative analysis of these models, using generalized (dimensionless) variables, where the characteristic (inherent) scales are the maximal or average values of the variables, is presented. The using of the convection-diffusion type of models for quantitative analysis of the processes in column apparatuses is not possible because the velocity function in the convection-diffusion equation is unknown. The problem can be avoided if the average values of the velocity and concentration over the cross-sectional area of the column are used. The average concentration models permit to analyze the effect of the radial nonuniformities of the velocity and the concentration on the process efficiency in the column and to solve the scale-up problem. The convection-diffusion type of models are presented as a base for to be created convection and diffusion type of models.