Acetone - Water Vapor-liquid Equilibrium Thermodynamic Properties Of Binary Systems Research And Physical State Equation

Acetone as a kind of important chemical raw materials production plays an important part in the national life. Acetone is a typical low-boiling substance and commonly used as refrigerant, meanwhile, it is used for studying cooling effect and vapor-liquid equilibrium. However, common acetone is not pure. They mostly appear as the acetone solution, which is composed of mixture of acetone and water. When the problem comes to purification and distillation, thermodynamic properties of acetone-water binary systems becomes an important issue of concern, especially the vapor-liquid equilibrium thermodynamic properties. In this issue, equation of state has an important role in the study of vapor-liquid equilibrium problems, so this paper has studied thermodynamic properties of vapor-liquid equilibrium of acetone-water binary system and equation of state.This study reviewed a typical equation of state for mixture; and then, it summarized typical mixing rules; next, it introduced the equation of state for two typical applications in the calculation of vapor-liquid equilibrium thermodynamic properties.A set of equipment was designed and built in this study. It is used for measuring vapor-liquid equilibrium of acetone-water binary system and obtaining thermodynamic data, which mainly contains experimental temperature T and saturation vapor pressure P of the test equipment. The experimental devices were introduced and calculated corrections were made.Through the experiment, acetone-water binary systems vapor-liquid equilibrium thermodynamic data were obtained, the feasibility of the experimental device wre confirmed. Based on analysis by drawing on experimental data and comparision of the saturated vapor pressure of the typical equation of state, a suitable acetone-water binary system P-T equations vapor pressure of saturated vapor-liquid equilibrium calculations were proposed. The phase diagrams (component diagrams) of acetone-water binary system in the vapor-liquid equilibrium were calculated and drew by using experimental data; the variation with temperature, the initial components, pressure in phase diagrams were analyzed. After calculating and analyzing the boiling point of acetone-water binary system, the regularity conclusions were obtained. The above calculation and analysis methods are ubiquity and applicable to most computing VLE (vapor-liquid equilibrium) mixture analysis.Based on statistical physics, this paper describes the theoretical derivation of the equation of state of liquid method from a general method derived from the theoretical equation of state; then it calculates the acetone and water molecules partition function with an approximate method and then derives the acetone-water binary system vapor equation of state; it provides a method which deduces equation of state of the gas-liquid coexistence phase theoretically, especially for the equation of state and the specific gas-liquid coexistence of vdW fluid system in detail, in addition, this method can be extended to acetone-water binary system. The above methods about the theoretical derivation of state equation are universal and applicable to theoretical derivation of extensive fluid.