Hollow fibers bundle

Modules and Housings Modern gas membranes are packaged either as hollow-fiber bundles or as spiral-wound modules. The former uses extruded hollow fibers. Tube-side feed is preferable, but it is limited to about 1.5 MPa. Higher-pressure applications are usually fed on the shell side. A large industrial permeator contains fibers 400 pm by 200 pm i.d. in a 6-inch shell 10 feet long. Flat-sheet membrane is wound into spirals, with an 8- by 36-inch permeator containing 25 of membrane. Both types of module are similar to those illustrated in Background and Definitions. Spiral modules are useful when feed... 

Hollow-fiber bundles, potting of, 76 16-18 Hollow fiber cell culture systems, 5 350, 355-356... 

Microfiltration units can be configured as plate and frame flat sheet equipment, hollow fiber bundles, or spiral wound modules. The membranes are typically made of synthetic polymers such as Polyethersulfone (PES), Polyamide, Polypropylene, or cellulosic mats. Alternate materials include ceramics, stainless steel, and carbon. Each of these come with its own set of advantages and disadvantages. For instance, ceramic membranes are often recommended for the filtration of larger particles such as cells because of the wider lumen of the channels. However, it has been shown that spiral wound units can also be used for this purpose, provided appropriate spacers are used. 

Solute rejection for four solutes and ultrafiltration rates for two protein solutions have been measured for high-flux cellu-losic hollow-fiber bundles of three lengths. 

End Seal Unitfor Typical Small Hollow Fiber Bundles... 

The membrane is in the form of a hollow fiber (see Fig. 109), which has the advantage of reduced outer dimensions together with a large membrane area. The membrane module consists only of the hollow fiber bundle and the module housing. Such a simple structure can avoid difficulties encountered with other membrane module designs, such as sealing of flat seat type and spiral-wound type membranes and furthermore can reduce not only the volume and the weight of the modules, but also the total system size. 

Figure 4. Formation of a hollow fiber bundle [17]. Continuous loops or shanks offibers are formed by unwinding fiber from spools (Fig. 10). Individual shanks are covered by an elastic sock to hold fibers in uniform spatial position and facilitate subsequent handling (Fig. 12).

Figure 6. Formation of a hollow fiber bundle [17]. Tubesheets are formed by centrifugal potting (Fig. 19). Once formed, fiber lumens are opened by cutting off the end of the tubesheet along line CL (Fig 17 and 18).

Figure 13. Sources of non-ideal flows in hollow fiber bundles a) fluid distribution from the inlet manifold into the fiber bundle and b) fluid distribution within the fiber bundle. Fluid distribution from the lumen manifold into the fiber lumens (a, left hand side) can lead to higher flow rates in the fibers in the center of the bundle. Fluid distribution from the shell manifold (typically a fiber free collar that extends around the fiber bundle) into the shell can lead to higher flow rates near the inlet port than opposite it. Assuming a common pressure drop across all fibers lumen flows are higher in larger fibers (b, left hand side). Similarly, assuming a common pressure drop along flow channels in the shell, shell flows are higher in larger channels.

Figure 18.7 Photos of (a) LSCF hollow fiber membranes (b) hollow fiber bundles and (c) hollow fiber membrane module. ...

Let us now solve (differential) Equations 7.32 to 7.34 established in the hollow fiber bundle (the radial coordinate, r, being the independent variable) and the differential Equations 7.3,7.9, and 7.10 established on the bore side of the hollow fiber (the axial coordinate, x, being the independent variable), simultaneously. Although (differential) Equations 7.3, 7.9, and 7.10 are written in the form of partial differential equations, they are actually ordinary differential equations, since x is the only independent variable at a fixed r. Quantities di, U and are known as hollow fiber and hollow fiber bundle geometry. A and B are membrane transport parameters and arc known for a given membrane, k is the mass transfer coefRcient, which depends on the module geometry and the solution flow rate. 

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