The Separation And Purification Technology Of1,3-propanediol From Fermentation Broth By Extraction Method

1,3-PD is widely used in organic synthesis as chemical intermediate,which is an important monomer for the production of high performance polyester.Now,microbial conversion of glycerol into1,3-Propanediol has been given much attention due to its renewable resource and high boiling point and strong hydrophilicity,the recovery of1,3-PD from a complex and dilute fermentation broth has become a bottleneck for the development of a commercially viable process.The solvent extraction rout for the separation and purification of1,3-PD from fermentation broth was explored in the paper.First,the common solvent extracting ability of1,3-PD form the fermentation broth was studied by the reagents of n-butanol and n-hexanol,and the optimal extractant was chose.The results show that the1,3-PD extracted fraction of94.4%was obtained at room temperature,normal pressure,the3volume ratio of n-butanol and fermentation broth and eight stages extraction.Second,the extraction ability of various organic solvents/norganic salts system was compared, ethanol/dipotassium phosphate system was proved to be the best one.The phase composition was30%(wt) of ethanol and30%(wt) of dipotassium phosphate for the flocculated broths,and the coefficient and yield of1,3-propanediol was0.15and96.25%,respectively.The recovery of dipotassium phosphate in the bottom reached81.4%,when1.0volume of ethanol was added to the bottom after adjusting PH value to4.0.Third,n-butanol/n-heptane was the optimal composite extractant.The volume fraction of n-heptane,the volume ratio of composite extractant and the condensed fermentation broth and multistage extraction were discussed.The results show that the1,3-PD extraction yield of91.2%was obtained at the volume fraction of30%n-heptane,the3volume ratio of n-butanol/n-heptane and fermentation broth and eight stages extraction.Fourth,the property of composite extracting1,3-PD from fermentation broth in the reciprocating sieve plate extraction column(RPEC) was studied.The influence of the structure parameters and operation conditions on the extraction yield of1,3-PD was discussed. The results show that the1,3-PD extraction yield of91.2%was obtained at the volume fraction of30%n-heptane,the1volume ratio of n-butanol/n-heptane and fermentation broth,the free area rate of tray of53%,tray spacing of7cm,vibrating frequency of200r.min-1and retention of30mins. Fifth,LLE datas were determined for compose extraction-1,3-PD-water ternary system at20,25,30,35,40,45℃under normal pressure and drawed in triangular diagrams.At last,I outlined a method to design for RPEC by producting the ten thousand tons1,3-propanediol every year.