Analysis and experimental study on liquefaction characteristics of SF6/CF4 mixture gas

Using SF
₆
mixed gas instead of pure SF
₆
gas can effectively solve the problem of cryogenic liquefaction. However, it is necessary to verify the applicability of Dalton's Law of Partial Pressure when it is applied on analyzing the liquidation problem of SF
₆
mixed gas. In this paper, SF
₆
/CF
₄
gas mixture is taken as an example to introduce a problem that if the mixture can meet requirement under temperature of -40°C. In order to solve the problem, this paper firstly make theoretical analysis and assumption, make the above problem be equivalent to the problem that calculation of partial pressure of SF
₆
in gas mixture. After that, SF
₆
parameters can be calculated using Beattie-Bridgman formula. The Virial equation is used to calculate the parameters of gas mixture, calculate the second Virial coefficient of binary mixture in terms of the interaction between gas molecules; Finally, calculate the partial pressure of SF
₆
in the mixed gas by combining the real gas state equation, the second Virial coefficient calculation equation and the partial pressure relation equation; after that, the conclusion of that if the mixed gas meet the requirements under the temperature of -40°C is drawn. Meanwhile, a cryogenic liquefaction test is carried out to prove the feasibility of the conclusion. This paper presents a method for analyzing the liquefaction characteristics of SF
₆
/CF
₄
mixture, and also verifies the error when applying Dalton's Law of Partial Pressure on mixed gases.