Physico-mathematical modeling of fluoride hydrogen desublimation from gas mixtures onto walls of a condenser

To reduce expenditures for cooling of desublimation tanks, the possibility to use cold air as a refrigerant with a temperature of 113 K is considered. The article describes the process of fluoride hydrogen desublimation from gas mixtures onto walls of the tank-desublimator. A mathematical model of hydrogen fluoride desublimation in the presence of air is constructed. The desublimation process was calculated for cases where the tank is cooled by liquid nitrogen down to the temperature of 77 K and by cold air with a temperature of 113 K. Results of numerical simulation of the hydrogen fluoride desublimation process under the condition of the association of six molecules are presented. With an increase in the degree of association, the speed of purification of the gas mixture from hydrogen fluoride is significantly reduced. The results of the numerical simulation show that hydrogen fluoride reaches the wall temperature of the container-desublimator in the first third of the container both in the case of liquid nitrogen cooling and in the case of cooling by cold air. The concentration of hydrogen fluoride in both the cases corresponds to the pressure of saturated vapors at appropriate temperatures.