Study On The Pocess Of Crystallization Of Betaine

Betaine, as a neutral species, is widely distributed in animal, plant and microorganism. In the body of animal, betaine can provide efficient methyl, so it can replace part of methionine and choline and effectively organize the deposition of fat, it is also a kind of buffer substances and osmotic regulation. Therefore, betaine is widely used in feed, pharmaceutical and chemical industry. At present, it is use chemical synthesis to make the betaine, but sodium chloride and betaine as reactants are both exist in the system, which has some negative effect on the separation and purification of betaine. It is commonly use extraction crystallization to separation betaine, but this method is highly energy consuming, small particles. Therefore, it is imperative to research the new separation method to purification betaine.Currently, there are various conventional methods of separation, but they have various defects. Standard crystallization methods are difficult to achieve separation of crystallization. This paper analyzes dissolved-cooling crystallization method could isolation and Purification of betaine, crystallization process design and analysis depend on the precise solubility and metastable zone thermodynamic data, in addition, thermodynamics of the data is also affected the yield and purity, crystal structure, particle size distribution of the product and so on. Therefore, it is necessary to determined the solubility of betaine in pure solvent and mixed solvent before study the crystallization process. In this paper, a laser dynamic method is use for the determination of betaine solubility in pure solvent (acetic acid, ethylene glycol, DMSO,1-pentanol and isoamyl alcohol) and mixed solvent (methanol+ethyl acetate, methanol+amyl alcohols, methanol+2-butanol) also uses this method for the determination the metastable zone of betaine in methanol+2-butanol system. These studies will provide the basis of thermodynamics of betaine. The above thermodynamic basic research will provide the theory basis for the later betaine industrial production.Experimental determination of the crystallization thermodynamics research is essential, however, due to the limitations of the experimental measurement, it is also need a combination of mathematical models of thermodynamic to correlate and predict the unknown point. The five thermodynamic model:λh equation, van’t Hoff equation, ideal model, Wilson equation and NRTL equation were associated for the solubility of betaine in pure solvents. And the simplified Hybrid model is used to correlate the solubility of betaine in mixed solvents. Moreover, based on van’t Hoff equation, the dissolution enthalpy, entropy and Gibbs free energy of solution dissolved was predicted.According to the above study of thermodynamic properties of betaine, the solventing-cooling crystallization process was designed to separation betaine. Through the experimental study and theoretical analysis, dissolving agent by category, study on solvent variable method of single factor solvent composition, temperature range, crystallization time, flow rate and stirring speed influence on the purity and yield of the product, dtermination of the optimum solventing-cooling crystallization technological conditions of betaine The technology can improve the yield and purity of betaine purposes, the crystal product particles was get larger.