Research On Extraction Intensification Based On High-speed Counter-current Process And Complexation Reaction

Extraction is widely applied due to its great productivity,high separation efficiency,low energy consumption and continuous safe operation.Extraction intensification from physical and chemical aspects has been carried out in the dissertation,One intensification is to take advantage of a changeable synchronous planet centrifugal field in High-speed counter current chromatography(HSCCC) where two phases are subject to the repetitive processes of mixing and settling,and thus solutes can be separated with high efficiency.The other is to make use of the driving force from complexation reaction.This method has great advantages in the separation of strong-polar organic compounds with high selectivity and high efficiency.Chapter 1 gives a review about the theories and characteristics of high-speed countereurrent process and complexation extraction,mainly focusing on mass transfer behavior and solvent system of HSCCC as well as application ofcomplexation extraction.Chapter 2 deals with the axial dispersion coefficient in HSCCC from the angle of mass transfer.Experiments were implemented with KI which was not soluble in upper phases.Axial dispersion coefficients in dual phases were measured and a comparison was made with those in single phases.Moreover,a mathematical model based on dimensionless numbers was set up. The model describes the influences of apparatus parameters,rotation speed,velocity,solvent properties on the axial dispersion coefficients.Chapter 3 deals with ion-exchange extraction of glucosamine hydrochloride with sodium di-(2-ethylhexyl) phosphoric acid(D₂EHPNa) from the angle of complexation reaction.The effects of temperature,initial concentrations of D₂EHPNa and glucosamine hydrochloride and pH of aqueous solution on distribution coefficient were investigated.A mathematical model about distribution coefficient was proposed and four special cases were discussed.Chapter 4 deals with distribution coefficient liquid-liquid equilibrium.A calculation method about distribution coefficient was given based on UNIFAC model.A program concerning activity coefficient and liquid-liquid equilibrium was developed using VC++ and distribution coefficients of some natural products were calculated. Chapter 5 summarizes the main contents of the dissertation,and several research suggestions about distribution coefficient in liquid-liquid equilibrium and hydrodynamic behaviors in HSCCC were proposed.