Study On Nanofiltration Process Of Organic Solution

Under the orientation toward developing applied nanofiltration(NF) technology, studies were systematically carried out on the performance characterization and prediction of the spiral wound NF membranes, the components separation of glucose/sucrose solution, as well as the purification of L-phe(L-phenylalanine)fermentation broth.Characterization of the spiral wound NF membranes and prediction of separation performance The S-K model and the Zeman-Wales model were jointly employed for descriptions of NF experiments of dilute neutral organic solutions with DK4040C and HL4040F spiral wound NF membranes, thus the empirical correlations among the solute rejection and solute Stokes radius, molecular weight were established. By evaluation through modelling, the average pore radius of DK4040C and HL4040F were determined as 0.51×10-9m and 0.49×10-9m respectively. Good descriptions of solute rejections was obtained with the model parameters of either solute Stokes radii or molecular weights, which was expected to low the necessity of NF experiments, broaden the applications of NF technology, and guide the technical choice of NF membranes. Study on NF process of neutral organic hybrid solution The NF process of glucose/sucrose solution with DK4040C NF membranes were investigated. The results showed that the operation conditions played an important role in influencing glucose rejection, which affected the separation effects of hybrid solutions. For the glucose/sucrose hybrid solutions, at the same permeation flux, observed rejection of one component decreased due to existence of the other one; as the permeation flux increased, the separation ratio decreased and would approach the separation limit. The separation direction of neutral organic hybrid solutions was further discussed. As an example of industrial application,the NF process of Jerusalem artichoke leaching solution for wiping off monose was investigated, and an optimal flowchart was proposed.Study on purification of L-phe fermentation broth by membrane technology The studies on purification L-phe fermentation broth with integral membrane technology (MF, UF, NF) were investigated. The GH4040F spiral wound UF membrane was chosen for experimental studies on deproteinization process of L-phe fermentation broth. Under operation pressure of 1.76MPa, bulk flow rate of 0.17m·s-1 and temperature of 313K, the average permeate fluxes reached 6.2×10-6m·s-1, the average rejection of L-phe was about 25%, and the average rejection of albumen was over 90.0% after MF process. By comparison of the separation effects between DK4040C and HL4040F membranes, it is found the yield of L-phe was more than 95% through a two-stage series figuration, the average flux was 11.75×10-6m·s-1 and 18.69×10-6m·s-1 respectively. The process design was then given for a 500t/year membrane separation project, the results showed that the integral membrane process resulted in high yield, low wash water demand and little waste water.