New Approach to Modeling and Simulation of Chemical and Mass Transfer Processes in Column Apparatuses

Objective: The classical mass transfer theory is not applicable for modeling the mass transfer of chemical, absorption, adsorption and catalytic processes in column apparatuses, where the velocity distributions and interphase boundaries are unknown. The modeling of these processes is related with the creation of new type of convection-diffusion models (for qualitative analysis) and average-concentration models (for quantitative analysis), where the surface reactions are replaced by equivalent volume reaction, while the velocity and concentration distributions are replaced by average velocity and concentrations. The effect of the radial non-uniformity of the velocity in the average-concentration models is introduced by model parameters, which must be obtained experimentally. Methods: The new convection-diffusion and average-concentration models are obtained in the cases of different processes in column apparatuses: simple and complicated chemical reactions, physical and chemical absorption, physical and chemical adsorption, heterogeneous catalytic processes (physical and chemical adsorption mechanism). These models are presented in the monograph Chr. Boyadjiev, M. Doichinova, B. Boyadjiev, P. Popova-Krumova, “Modeling of Column Apparatus Processes” (Second edition), Springer- Verlag, Berlin Heidelberg, 2018. Results: Two hydrodynamic situations are considered, when the radial velocity component is equal to zero, in the cases of an axial modification of the radial non-uniformity of the axial velocity component and when the radial velocity component is not equal to zero. Conclusion: The use of experimental data, for the average concentrations at the column end, for a concrete process and column, permits to obtain the model parameters, related with the radial non-uniformity of the velocity. These parameter values permit to use the averageconcentration models for modeling of different processes.