Phase Equilibria And Calculations Of Binary Systems Containing Nitrogen

With the development of the research on phase equilibria, more phase equilibrium data of different systems are measured and calculated by using many methods. The content of nitrogen in the air is the most. However, the phase equilibria containing N₂ and ester are few. So the systems containing N₂ and four esters have been experimentally investigated and calculated.A set of variable-volume autoclave with a quartz window has been made domestically for the first time. The accurate volume of a sample can be measured with a Hall-effect probe, and the precise adjustment within wide range of temperatures and pressures can be actualized. At high pressure, the samples can be taken directly from the autoclave with a small steel vessel. So the accurate vapor-liquid equilibrium data can be obtained. A simple equipment was also built up for the analysis the composition of the vapor and liquid samples. The vapor-liquid equilibrium data (including ingredient, density and volume) of the four binary systems (N₂+ dimethyl carbonate, N₂+diethyl carbonate, N₂+ ethyl acetate and N₂+ ethyl propionate) have been measured at different temperatures and pressures with isothermal static analytical method. The vapor-liquid equilibrium data show that the solubilities of N₂ in four esters increase drastically with increasing pressures at the given temperatures, but the contents of four esters in gas phases increase faintly. The solubilities of N₂ in the carbonate esters are higher than that in fatty acid esters, which reveals the principle that the similar structure makes the high solubility. And the higher the molecular weight is, the longer the carbon line is, the lower the solubility of N₂ is. However the contents of the four esters in N₂ are all low, and the differences among the contents are very little.The high-pressure GLE data are also calculated with eight methods for above four systems. The PR and PRSV EOS and four different mixing rules are used. The Suitability of those EOSs and calculated precision are discussed systemically. Three methods showed excellent calculation effects which each other were made up of (PR EOS with activity coefficient and associated theory) and (PR EOS with var der waals mixing rules).