A Study on Ultrafiltration in Hollow-Fiber Membrane Modules

• Main Authors: Hsiang-Hui Wu, 吳祥暉
• Other Authors: Ho-Ming Yeh
• Format: Others
• Language: zh-TW
• Published: 1994
• Online Access: http://ndltd.ncl.edu.tw/handle/95639457230789300122

碩士 === 淡江大學 === 化學工程研究所 === 82 === Ultrafiltration is a pressure-driven membrane process used for the separation of macrosolutes from a solvent, usually water. The permeate flux of ultrafiltration of macromolecular solution is usually analyzed by the gel polarization model 、 the osmotic ressure model and the resistance-in-series model. In the present study, the gel polarization model and the resistance-in-series model have been modified to improve the theoretical predication. Experimental work has been carried out for polyvinylpyrrolidone solutions which were ultrafiltrated by using polysulfone hollow fiber membrane module. The experimental data agree quite well with the correlation equation based on the modified resistance-in- series model. This modified model was then employed for optimum design of a hollow fiber membrane module with total length of hollow fibers N*L fixed . It was found that under certain solution concentration Ci、 volume flow rate and trans- membrane pressure at the inlet,incereasing the length of a hollow fiber L (or decresing the number of hollow fiber N) will increase the fluid velocity in hollow fiber Ui. Furthermore, since the increase of Ui have two con- flict effect: one is the desirable effect of decreasing the resistance of gel layer on the fiber wall which is is good for ultrafiltration, and the other one is the un- desirable effect of decreasing the transmembrane pressure which is bad for ultrafiltration . Therefore , with total length of hollow fiber ， there exists an optimum length L as well as optimum number N of a hollow fiber for maximum permeate flux.