Research On The Separation Of Partially Miscible Of Azeotropic Organic/water Systems By Salting-out Extraction

The separation of partially miscible cyclohexanone - water and n-butanol - water systems based on salting-out principle is studied by the combined methods of theoretical analysis and experimental research, including the selection of inorganic salts, the liquid-liquid equilibrium(LLE) experiments and salting-out extraction process, and a theoretical model is established by the calculation of LLE data.Currently, it has an important application background for the salting-out extraction of partially miscible of azeotropic organic/water system in industry. Compared to conventional azeotropic distillation and extractive distillation process, this method can greatly reduce the energy consumption and is also consistent with the development of low-carbon. When the salt is added into the miscible azeotropic organic/water system, the interaction between the ions of salt and solvent molecules will change the LLE of this system and the partition coefficient of solvents to get the mixture separated. This is the salting-out effect of inorganic salts. Until now there are not so many reports about the research of partially miscible of azeotropic organic/water system by salting-out extraction exist and the LLE data of organic/water system is short, which brings a lot of difficulties to its research and application. In this paper the LLE of cyclohexanone-water-salts and n-butanol-water–salts systems are studied, providing the basic data and theoretical basis for the salting-out extraction's application in industry. So it has an important academic theoretical significance and industrial application. The research works have been performed in this paper as follows:1 The selection of inorganic salt used in the process of salting-out extraction. By the combined methods of theoretical calculations, literature data and experimental study, the salts used in the separating process of cyclohexanone-water and 1-butanol-water systems are selected. The theoretical models of salt selection are studied by the experimental verification method and its scope of application is determinated, which provides theoretical data for the selection of inorganic salt in the process of salting-out extraction.2 Research on the LLE of cyclohexanone - water - salts and n-butanol - water - salts systems.The LLE data of the systems of cyclohexanone - water - potassium carbonate, cyclohexanone - water - potassium fluoride, n-butanol - water - potassium fluoride, n-butanol - water - potassium carbonate are experimentally measured, providing basis data for the separation of cyclohexanone/water and n-butanol/water systems by salting-out extraction.3 Study on the mathematical model for the LLE of cyclohexanone - water - salts and n-butanol - water - salts systems. The LLE data of the systems of cyclohexanone - water - potassium carbonate, cyclohexanone - water - potassium fluoride, n-butanol - water - potassium fluoride, n-butanol - water - potassium carbonate are calculated by the Pitzer electrolyte solution theory and NRTL, Wilson or UNIQUAC equations, respectively. It provides a theoretical basis for the separation of cyclohexanone - water and n-butanol - water systems by using inorganic salts.4 The technical study on the separation of n-butanol - water system by Salting-out extraction ways. According to the experimental results of liquid - liquid equilibrium, the potassium carbonate is selected and used to separate n-butanol/water system by salting-out extraction. The stability of aqueous potassium carbonate and mass ratio of aqueous potassium carbonate to raw materials on the extraction efficiency are investigated, and the optimum extraction ratio is obtained. Then the utilization process of high concentrations of n-butanol effluent with lower energy consumption is established. To compare the energy consumption of azeotropic distillation process and the salting-out extraction process, the processes are simulated and calculated by Aspen Plus simulation software and result shows that salting-out extraction process can be greatly reduced energy consumption in the separating process of this system.