| Abstrakt: |
Introduction. The purpose of the work is mathematical modeling of the process of drying the titanium dioxide TiO2 paste, which takes place under the conditions of hydrodynamics of vortex fluxes of heat carrier and continuous dispersion, which will increase the efficiency of heat and mass transfer processes and reduce energy costs. Materials and methods. The process of drying the finely divided paste of TiO2 in the vortex fluxes of the coolant with the use of continuous dispersion of the starting material was carried out in a conical drying chamber of the drying apparatus equipped with a special device for dispersing the material in the lower part and the zone of drying in the upper part. Results and discussion. The process of drying the titanium dioxide paste in the vortex flow of the heat carrier during the application of the original design of the drying apparatus with the dispersant and the zone of drying of the material to a high residual dryness of 99.7% is implemented. Enriched intensive grinding of conglomerates of the material and their mixing with an already dried fine powder with an equivalent diameter De = 100-200 μm and a density ρTiO2 = 4,23 g/cm³ has been carried out here. The presence of separation zone of particles of the already dried powder from conglomerates of the paste provides effective grinding of the latter and an increase in the contact surface of the wet material with the coolant. Specific load of the surface of the layer of conglomerates of the paste TiO2 in the vortex flow for moisture has the value af = 138-155 kgvol/(m²·h). A physical model of paste drying was selected. On the basis of the physical model, a mathematical model of the process, consisting of differential equations of the first order, describing the dependence of change in the temperature of the heat carrier and the material particles from the drying time, as well as the dependence of change in the moisture content of the material from the drying time, was developed. Given the continuous grinding of wet material, this model allowed determining: the conditions of the process, namely, the temperature at the entrance to the drying chamber should be 95-120°C, the flow of the coolant 60-80 m³/s, the moisture content of the paste TiO2 not more than 50. Conclusions. The kinetics of the process of drying the titanium dioxide paste was studied and a physical, based on the modified mathematical, model was obtained that allowed determining the drying time of the wet material and the main kinetic parameters of the drying process. [ABSTRACT FROM AUTHOR] |
