Analysis of using binary cryogenic mixtures containing nitrogen and alkanes or alkenes in cryocoolers

This paper describes the working mechanism of binary cryogenic mixtures containing nitrogen and alkanes or alkenes. The Peng-Robinson equation of state is used to calculate the mixed free enthalpy of these mixtures and a method to calculate the mutual solubility is also suggested. Finally, the vapour-liquid, liquid-liquid and vapour-liquid-liquid equilibria of these mixtures are analysed. Therefore, an effective method to predict the characteristics of new kinds of binary cryogenic substances is provided in this paper.