Hollow fiber permeator

Hollow-fiber permeators, 26 22 Hollow fibers, 13 389-390 cellulose ester, 26 19 cellulosic, 26 18-20 ion-exchange, 26 15 mechanical considerations and dimensions for, 26 5-7 natural polymer, 26 23 polyacrylonitrile, 26 23 polyamide, 26 21-22 post-treatment of, 26 13-14 preparation of, 26 3 production of, 19 757 with sorbent walls, 26 26 technology of, 26 27 wet spinning of, 25 816, 817-818 Hollow-fiber spinning processes, 26 7-12 Hollow fiber spinning technology,... 

These considerations and the set of equations for transport of the solute through the HF modules are modified and simplified in comparison to the HFCLM [91] theoretical considerations. The models presented in Sections 13.2.1 and 13.2.2 consider more detailed diffusion parameters at the F/LM and LM/R interfaces, more detailed kinetics of chemical reactions. So, they are more identical to the real transport processes, therefore, these models, modified for a hollow-fiber permeator, may be used for the hoUow-fiber transport also. 

Du Pont does not currently market Permasep permeators for gas separations. They did, however, in the B-1 Permasep permeator, introduce the first commercial, hollow fiber permeator for gas separations. This permeator employed hollow fibers of polyethylene terephthalate as the membrane. Later, permeators having aramid hollow fiber membranes were field tested for hydrogen separations. Du Pont is presently actively engaged in research for the development of membrane technology for a wide variety of applications. 

Results and Discussion. Figure 14 demonstrates the principal of separation through Ion-exchange membranes, where the counter-lon/permeate Interactions determine the mass transport properties of the system. In this set of experiments, the feed mixture was an azeotropic composition of 2-propanol and water (88.5/11.5 wt.X). A Naflon hollow fiber permeator was used In pervaporatlon mode. The... 

FIGURE 20.1-2 Early Dow hollow-fiber permeation device, Note that permeant is withdrawn from both ends. 

Example 26.2. A gas containing 70 percent Hj, 24 percent CH, and 6 percent C2H6 is to be separated into a nearly pure stream and a fuel gas using a hollow-fiber permeator with a selectivity of 100 for H2/CH4. (a) If the upstream and downstream pressures are 600 and 300 lbj-/in. absolute, what fraction of in the feed is recovered in the permeate if the permeate is 96 percent H What is the stage cut (6) How much more could be recovered by lowering the permeate pressure to 180 Iby/in. absolute ... 

Example 26.4. A hollow-fiber permeator with d, = 300 /rm and d-, 200 /an gives a water flux of 10 gal/day-ft with O.I Af NaCl solution at 20°C, and the salt rejection is 97 percent. Feed solution flows normal to the fibers at an average superficial velocity of 0.5 cm/s. Is concentration polarization significant ... 

An alternative approach to solving stability problems with ILMs is presented by Bhave and Sirkar (114). Aqueous solutions are immobilized in the pore structure of hydophoblc, polypropylene hollow fibers by a solvent exchange procedure. Gas permeation studies are reported at pressures up to 733 kPa with the high pressure feed both on the shell and lumen sides of the laboratory scale hollow fiber permeator. No deformation of the hollow fibers is observed. Immobilizing a 30 weight % KjCO, solution in the hollow fibers greatly improved the separation factor, a(C02/Na). from 35.78 with pure water to 150.9 by a facilitated transport mechanism. Performance comparisons with commercial COj separation membranes are made. 

R. J. Gardner, R. A. Crane, and J. F. Hannan, Hollow Fiber Permeator for Separating Gases,... 

N. Parthasarathy, M. Pelletier, M.L. Tercier-Waeber, J. Buffle, On-line coupling of flow through voltammetric microcell to hollow fiber permeation liquid membrane device for subnanomolar trace metal speciation measurements. Electroanalysis 13 (2001) 1305—1314. 

In earlier chapters we have studied gas separation via gas permeation in two permeator configurations in a completely mixed membrane gas permeation cell (Section 6.4.2.2) in crossflow membrane permeators (Section 7.2.1.1). In the shell-side fed hollow fiber gas permeator of Figure 7.2.1(d), if the permeate is withdrawn from the fiber bore at the feed end only (the other end is closed), then we have countercurrent flow between the feed side and the permeate side. We consider such a gas permeator configuration here via Figure 8.1.51(a) this figure does not show a hollow fiber. However, one could easily model a hollow fiber permeator with the permeate side being the fiber bore (I.D., dj O.D. do). We wiU now develop the governing balance equations for the countercurrent gas... 

There is a tube sheet at the end of the hollow fiber permeator for potting every single hollow fiber. The permeated gas in the fiber bore will undergo some pressure drop in this section however, there is no gas permeation. 

In 1996 Medal launched a new generation of hollow-fiber permeation membranes, based on polyimides. ... 

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