Seals membrane module

INORGANIC MEMBRANES SYNTHESIS AND APPLICATIONS 3.6. END-SEAL AND MODULE PACKING MATERIALS... 

Figure 19.4. The spiral wound membrane module for reverse osmosis, (a) Cutaway view of a spiral wound membrane permeator, consisting of two membranes sealed at the edges and enclosing a porous structure that serves as a passage for the permeate flow, and with mesh spacers outside each membrane for passage of feed solution, then wound into a spiral. A spiral 4 in. dia by 3 ft long has about 60 sqft of membrane surface, (b) Detail, showing particularly the sealing of the permeate flow channel, (c) Thickness of membranes and depths of channels for flows of permeate and feed solutions.

Modules are connected to each other using an interconnector adaptor, as shown in Figure 4.19. The interconnector has O-rings at ether end to ensure a tight seal with the module ATDs. These O-rings can roll upon installation into membrane modules, thereby... 

All spiral wound modules also have a brine seal (see Figures 4.23a and 4.23b). The brine seal is a U-cup-shaped rubber gasket material that is used to prevent feed water from passing by on the outside of the membrane module, thereby preventing feed water from bypassing the membranes (see Figure 4.24). The brine seal... 

Proper installation of membrane modules into a pressure vessel is critical. The membrane modules are guided into the pressure vessel in series. Membranes should be loaded into pressure vessel in the direction of flow. That is, the concentrate end of the module (the end without the brine seal) is inserted first into the pressure vessel. The brine seal and O-rings on the module inter-connectors can be... 

Shims Shims are used to prevent modules from moving back and forth during pressurization and depressurization. Such movement could wear on the internal O-ring seals. Shims are plastic spacer rings similar to washers. They are typically 0.20-inches thick, and can be purchased from the manufacturer of the pressure vessel or fashioned from polyvinylchloride (PVC) pipe. Shims fashioned from PVC pipe must be cut parallel and free of burrs to work correctly. They are installed between the face of the lead membrane module and the adapter hub (see Figure 6.16) after all the... 

FIG. 22-53 Spiral -wound module used in many membrane processes. Permeate collection material is wound on a perforated permeate pipe. A membrane sandwich is constructed over the permeate carrier using glue seams as seals. Membrane sandwiches are separated by feed-channel spacers, through which the feed stream is passed. Courtesy Koch Membrane Systems. )... 

Two types of connection (and therefore sealing) are involved in assembling membrane modules. The first type connects tubular or monolithic membrane elements in bundles using header plates at the ends and, in some cases, in the middle of the module length. The second type provides sealing between the plates and the module housing. 

A membrane system consists of many membrane modules which, in turn, are made of several membrane elements. Both ends of a membrane element are sealed with such materials as enamels or ceramic materials. The connections between elements and between elements and the housing or pipings are typically made from plastics or elastomers for liquid phase applications. 

Different supports are used, (see Section 10.6.4) with different geometry (discs or tubes), thickness, porosity, tortuosity, composition (alumina, stainless steel, silicon carbide, mullite, zirconia, titania, etc.), and symmetry or asymmetry in its stmcture. Tubular supports are preferable compared to flat supports because they are easier to scale-up (implemented as multichannel modules). However, in laboratory-scale synthesis, it is usually found that making good quality zeolite membranes on a tubular support is more difficult than on a porous plate. One obvious reason is the fact that the area is usually smaller in flat supports, which decreases the likelihood of defects. In Figure 10.1, two commercial tubular supports, one made of a-alumina (left side) and the other of stainless steel (right side) used in zeolite membrane synthesis, are shown. Both ends of the a-alumina support are glazed and both ends of the stainless steel support are welded with nonporous stainless steel to assure a correct sealing in the membrane module and prevent gas bypass. 

It is helpful to think of a simple membrane process as shown in Figure 8.1. A hydrogen-selective membrane is sealed within a housing (pressure vessel) to make a membrane module. The feed stream enters the membrane module, and hydrogen selectively permeates the membrane. The hydrogen-depleted raffinate stream exits the membrane module as does the permeate stream (enriched in hydrogen). The hydrogen partial pressure in each stream is denoted by PU2 where the subscripts f,... 

We can now design a preliminary pilot setup. We use a spiral-type, flowing liquid membrane module, developed by the Teramoto group [87, 88], in which the effective membrane area is about 40% of the total membrane area (the increase of the membrane area is mainly due to blocking of the membrane surface by spacers, and by the adhesive used to seal the sides of the module). For our system, the total feed-side membrane area is 570 m and the total strip-side membrane area is 763 m , in which 360 m is the area needed for the separation of the strip solution concentrated by copper. By designing standard, three-compartment spiral-type BAHLM modules, with 100 m of the membrane on each side (feed and strip), and two-compartment modules, with 200 m of the membrane, we will obtain a setup, of six standard three-compartment modules and one two-compartment module connected in consecutive order (see Fig. 6.7). After the fourth module, we will... 

Evaluate the ITM Syngas/ITM H2 processes using PDU data Conduct long-term stability tests of tubular membranes and seals at high pressure Demonstrate performance of pilot-scale membrane modules in PDU Complete membrane module design and select catalysts for the SEP Commission the ceramic Production Development Facility and fabricate SEP membranes Design and fabricate the SEP reactor... 

Installation of the PDU system was completed, and the PDU reactor system and PDU membrane modules were commissioned at high temperature and pressure with a s mgas mixture. The PDU integrates the various components of the ITM Syngas/ITM H2 reactor design and will be used to confirm the performance of the planar membrane modules and seals under commercial process conditions. The PDU reactor is shown in Figure 4. 

However, relaxation of gasket seals is not the only way that differential expansion can adversely affect the performance of membrane modules. It is important to remember that each membrane in the module is constrained by the module construction. If the membrane is in the form of a planar, flat sheet, then it is con-... 

Membrane-to-module sealing methods are very important and have been addressed briefly above. Indeed, the functionality of the membrane module is predicated on the assumption that the feed stream is isolated from the permeate stream and the external atmosphere, and that the permeate stream is also isolated from the external atmosphere. This is especially true for a membrane module that will be used to purify hydrogen, since leaks could result in fire or explosion hazards. 

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