Technology Of Separating Xylitol From Xylose/xylitol Mother Liquor

Xylitol mainly produced by chemical method using corncob as the raw materials,the disadvantages of the technology is refined purification process long, yield is nothigh. One important reason for xylitol lower yield is crystal loss, therefore, improvethe recovery in the mother xylitol can greatly improve the yield of xylitol.The second crystallization of the mother liquor, the mother liquor of xylitolwould be diluted, and then concentration, from crystallization, centrifugal and drying.The results found that due to the mother liquor xylitol containing fusel alcohol is more,lower purity, viscosity, not easy crystallization, lower yield, cannot satisfy therequirement of the product.Biotransformation is the second mathod to make the mother liquor xylosehydrogenation into xylitol, again by filtering, from hand in, concentration, crystal,centrifugal, drying, get xylitol crystals. The results found that fermented liquidpigment, protein is more, complicated composition, viscosity is bigger, the follow-upprocessing difficulties, and, using the yeast in the fermentation process ofconsumption of certain xylose maintain its normal physiological needs, make xylitolyields down.Simulated moving bed is mass transfer equipment based on chromatographicseparation principle for liquid separation operation. It is a continuous reflux operationmode, through the connection with the pillars of the separating agent, transform theimport and export of materials on fixed bed, which is equivalent to move down theabsorbent continuously, and raw material continuously move up the effect. Differentconstituents of the material were separated with the relative moving between materialand absorbents for different adsorption force.The simulated moving bed separation technology, will xylitol and other fuselalcohol separation, improve xylitol purity of purpose. The mother of xylitol andxylose mother liquor has the hydrogenation liquid test pilot and enlargement test,through the selection of equipment to the running parameters and determine theconditions, finally successful will xylitol the purity of the mother liquor increasedfrom the original70%to more than90%of the now, purification by enrichment,crystal, liquid centrifugal, drying process, get xylitol crystal, good fluidity anduniform grain yield of60%or more, the purity of99.8%or more,fully meet thexylitol the national drug standards.