Plate and frame configuration

In order for membranes to be used in a commercial separation system they must be packaged in a manner that supports the membrane and facilitates handling of the two product gas streams. These packages are generally referred to as elements or bundles. The most common types of membrane elements in use today include the spiral-wound, hollow fiber, tubular, and plate and frame configurations. The systems currently being marketed for gas separation are of the spiral-wound type, such as the SEPAREX and Delsep processes, and the hollow-fiber type such as the Prism separator and the Cynara Company process. 

The membrane module and design will obviously depend on the type of membrane used. The flat-sheet membranes are commonly constructed in a plate-and-frame configuration or as spiral-wound (SW) modules. F1F/CT/MTmembrane types are commonly manufactured into bundles that are installed in housing units or designed to be unconfined in the fluid, that is, immersed units. The membranes are... 

Figure 16.12 CEDI stacked-disk, plate-and-frame configuration. Courtesy of Siemens Water Technologies—Ionpure Products.

The major advantage of the spiral configuration over a plate-and-frame configuration is that there is minimal leakage associated with the spiral configuration. The spiral wound module does not require periodic tightening of nuts and bolts to prevent leaks, unlike plate-and-frame modules. Limitations of the spiral configuration include inferior current and flow distribution relative to plate-and-frame modules, as well as difficulty in assembly and field membrane replacement.17... 

The principle of operation for a cross-flow filtration system is to recirculate a liquid solution or suspension, usually using a positive displacement pump, through the membrane module, which may be arranged as multiple tubes, a spiral wound sheet or in a plate and frame configuration. The use of... 

Membranes are used to separate gaseous mixtures or liquid mixtures. Membrane modules can be tubular, spiral-wound, or plate and frame configurations. Membrane materials are usually proprietary plastic films, ceramic or metal tubes, or gels with hole size, thickness, chemical properties, ion potential, and so on appropriate for the separation. Examples of the kinds of separation that can be accomplished are separation of one gas from a gas mixture, separation of proteins from a solution, dialysis of blood of patients with kidney disease, and separation of electrolytes from non electrolytes. 

Cassette Cassette products are widely used in the biopharmaceutical industry and specifically dominate the protein concentration purification market due to their compactness, which provides excellent product recovery capabUity. Cassette modules contain presealed flat sheet membranes separated by feed and filtrate spacers. This is an improved design compared to earher plate and frame configurations, making installation and replacement much easier and more reliable for the end user (shown in Figure 14.5). 

In plate and frame modules, the membranes are placed (with or without spacers) between two plates. The packing density of this configuration varies between 100 and 400 m m, depending on the number of membranes or cassettes used. Andersson et al. [31] have used a plate and frame configuration for desalination purposes, where various cassettes were stacked together, each consisting of injection molded plastic frames of two membranes. Naveen et al. [92] used a plate and frame membrane... 

As the membrane acts as a separating medium between two flow compartments, these basic functions can be applied to liquid/liquid, gas/liquid and gas/ gas systems, respectively. The physical shape of the membrane strongly depends on the membrane material used. For polymeric systems, these can be flat sheets in a plate-and-frame configuration, spiral-wound modules, and tubular mem-... 

Plate-and-frame modules were the earliest version of membranes modules and are today still used in ultra-filtration and pervaporation processes. There is only one plate-and-frame configuration used in solution-diffusion membranes. This design may be relevant in the future for flat perovskite membranes. " " The most important elements of the module construction are "... 

The earhest reverse osmosis and ultrafiltration units were based on flat membrane sheets ia arrangements similar to that of a plate and frame filter press. Siace then, mote efficient membrane configurations, ie, tubular, spiral wound, and hoUow fiber, have emerged (96—98). 

This type of filter allows pressurized filtration of a slurry mixture to remove solids. A set of filter plates is sandwiched together in series with a configuration similar to the plates on a plate-and-frame heat exchanger. After the plates are compressed... 

Configurations used include tubes, plate-and-frame arrangements and spiral wound modules. Spiral wound modules should be treated to remove particles down to 20 to 50. im, while hollow fiber modules require particles down to 5 im to be removed. If necessary, pH should be adjusted to avoid extremes of pH. Also, oxidizing agents such as free chlorine must be removed. Because of these restrictions, reverse osmosis is only useful if the wastewater to be treated is free of heavy contamination. The concentrated waste material produced by membrane processes should be recycled if possible but might require further treatment or disposal. 

There are four basic forms for RO membrane modules Plate and frame, tubular, spiral wound, and hollow fine fiber. These four configurations are summarized in Table 4.3 and discussed below. Additionally, some manufacturers have developed other module configurations that are briefly discussed in Chapter 4.3.5. 

The difference between conventional dead-end filtration and cross-flow filtration is the configuration of the system. For large-scale operations, only cross-flow filtration will be used. The membranes for miocrofiltration as well as ultrafiltration are commonly utilized in a variety of filtration devices. There are three basic types of tangential flow filtration devices plate and frame, hollow fiber, and spiral wound membranes. 

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. 

A number of module designs are possible and all are based on the two types of membrane configuration, (i) flat sheet and (ii) tubular. These are plate and frame, spiral wound, tubular, capillary, and hollow fiber. 

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