Mathematical description of birch bark impregnation and heating process of birch bark with toluene

Abstract

On the basis of differential equations of heat and mass conductivity and given boundary conditions the mathematical model describing the process of heating and birch bark impregnation with an extractant was developed. Experimental facilities for impregnation and determination of mass conductivity coefficient are created. Kinetic dependence of average concentration of toluene in birch bark during impregnation is obtained. The temperature dependence of toluene mass conductivity coefficient through birch bark was obtained on the setup for determination of mass conductivity. The analysis of kinetic curves of birch bark impregnation with toluene at different temperatures shows a considerable influence of temperature on the impregnation rate. The discrepancy between the calculated and experimental data does not exceed 13%. The rational temperature of impregnation, which is 110 °С, has been determined. Optimum time of birch bark impregnation -10 minutes -has been determined. Developed mathematical model of the process of impregnation and heating of wood particles can be applied to organization of calculations of the process of extraction of biologically active substances from vegetable raw materials.