Experimental Study On Phase Equilibra Of Supercritical Fluids Processes

A large number of equilibrium data of dyestuffs and pure water in supercritical carbon dioxide (SC-CO2) are needed in the Supercritical Fluid Dying (SFD) as well as in the other supercritical processes such as micronization of aqueous drugs. The solubility experiments of C.I. Disperse Red 60, C.I. Disperse Orange 25 in SC-CO2 and SC-CO2 in pure water were conducted in this paper. The empirical equations and PR-equation were used to correlate and predict the results.The experiments of the solubility of C.I. Disperse Red 60 in SC-CO2 were carried out firstly. The two stages absorption of chlorobenzene was adoped to sampling, and the results were correlated by Ozcan empirical formula and PR-equation. The results show the solubility of C.I. Disperse Red 60 in SC-CO2 is very small with an order of 10~-6. The solubility increases with the increase of system pressure, and the higher temperature is, the larger increase of solubility with the increase of pressure is.After that, the partition coefficient of C.I. Disperse Orange 25 in SC-CO2 and Dacron system was measured for the practical SFD process. The method of the experiments was similar to C.I. Disperse Red 60. The Sung-Shim empirical formula and PR-equation were used to correlate the results and the better agreenment was obtained. The takeups of dyestuff on Dacron were determined by comparsen with the results of water dying experiments. The results show that the partition coefficient increases with the increase of the temperature and decrease with the pressure.At the end, the static equilibrium experiment method was used to measure the solubility of SC-CO2 in pure water. The weighing method was used to analyse the sample, and the mass flowmeter was used to measure the quatitive flow of CO2. The results were correlated with PR-equation and the good agreement was obtained. The results show that the solubility increases as the pressure increases, decreases as the temperture increases.A series of solubility data were obtained through the experimental and simulation work. The experments were conducted carefully with high precision apparatus, the results were also validated by PR-equation and empirical equation. Comparing with the results obtained by other researchers, the data are accurate, and they can meet the needs of basic data for design and calculations of supercritical processes.