Fiber tube, hollow

ZSM-5, etc.) Carbon Symmetric/ Microporous fiber Tube hollow fiber... 

TFF module types include plate-and-frame (or cassettes), hollow fibers, tubes, monoliths, spirals, and vortex flow. Figures 20-52 and 20-53 show several common module types and the flow paths within each. Hollow fiber or tubular modules are made by potting the cast membrane fibers or tubes into end caps and enclosing the assembly in a shell. Similar to fibers or tubes, monoliths have their retentive layer coated on the inside of tubular flow channels or lumens with a high-permeability porous structure on the shell side. 

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... 

An electrochemical reaction, the reduction of benzoquinone, is exemplarily described. An electrochemical micro structured reactor is divided into a cathode and anode chamber by a Nafion hollow-fiber tube. The anode chamber is equipped with a platinum electrode and the cathode chamber contains the analyte and carbon or zinc electrodes. Current density and flow rate are controlled to maximize current efficiency as determined by analysis of the formed hydroquinone by an electrochemical detector. Hydroquinone is extracted subsequently in a micro extractor from the resulting product stream [84],... 

In a multiphase membrane reactor, the conversion of benzylpenicillin to 6-aminopenidllinic acid is performed. The type of microstructured reactor used is a fermentation reactor which contains the enzyme penicillin acylase immobilized on the wall of a hollow-fiber tube. The hollow-fiber tube extracts 6-aminopenicillinic acid at the same time selectively. Benzylpenicillin is converted at the outer wall of the hollow fiber into the desired product, which passes into the sweep stream inside the fiber where it can be purified, e.g. by ion exchange. The non-converted benzylpenicillin is recycled back through the reactor [84],... 

N = number of hollow fiber tubes in membrane extractor module, =10,200 Q = volumetric flow rate (m3/s) t = time (s)... 

Different membrane shapes are used, such as plates, foils, spirals, hollow fibers, tubes, and even monilithic multichannel elements have been mentioned in the context of membrane reactors. In the following section, a general survey will be given indicating the main characteristics of the different types of inorganic membranes used in CMRs. More details can be found elsewhere [13-15]. 

The overall membrane element shape comes in different types sheet, single tube, hollow fiber, and multi-channel monolith. Photographs of some commercial membrane elements are shown in Figure 5.1. The use of disks (or sheets) has been confined to medical, pharmaceutical and laboratory applications, while tubes and monoliths are employed in larger-scale applications ranging from removal of bacteria from wine and beer fermentation to oil-water separation to waste water ueatmenL... 

The objective in membrane design is to pack as much permeation surface area into as small a space as possible to minimize operation requirements. Depending on the application, various membrane designs are used, such as flat sheet, disc tube, hollow fiber, spiral wound, and ceramic (17). Module design has a measurable effect on the hydrodynamic performance of the cross-flow membrane device. The advantages and disadvantages of different membrane modules are summarized in Table 1. 

During these 20 years, a large number of module systems has been made. The first idea was to use the conventional filter press, the plate-and-frame system, as done by Aerojet General Corp. However, this system never proved to be very successful in the U.S.A., and consequently new configurations, such as tubes, hollow fibers, and spiral-wound systems were invented. 

MEMBRANE PORE-SIZE TUBES HOLLOW-FIBERS... 

Perusal of the published literature on the topic of extrusion shows that a wide variety of thermoplastic binder systems have been used for the fabrication of fiber, hollow fiber, tube, sheet and honeycomb structures made of ceramic materials. Generally speaking, for thermoplastic extrusion to be successful, it is necessary that the binder system used consists of a major and a minor binder component, a plasticizer and a surfactant to ensure a good wetting of the ceramic powder. 

Membrane permeability overall Overall permeability coefficient <2r Volumetric flow rate r Internal radius of the hollow-fiber tube ri Hollow-fiber log-mean radius... 

Outer radius of the hollow-fiber tube T Absolute temperature... 

Consider first the membranes materials of construction, pore sizes and surface properties. Then consider options for operating membranes and the configurations for membranes hollow fibers, tubes, flat sheets and spirals. 

E. Hollow Fiber Tubes. The use of hollow fiber types of physically incorporated pesticides have been the last to be invented and developed. Insect pheromones, contained in hollow fiber tubes that were closed at one end, " were broadcast on the cotton fields to be protected. The effectiveness of the slow release is shown in Figure 6. 

---