Spiral wound cartridge

Spiral Wound. A spiral-wound cartridge has two flat membrane sheets (skin side out) separated by a flexible, porous permeate drainage material. The membrane sandwich is adhesively sealed on three sides. The fourth side of one or more sandwiches is separately sealed to a porous or perforated permeate withdrawal tube. An open-mesh spacer is placed on top of the membrane, and both the mesh and the membrane are wrapped spirally around the tube (Fig. 16). 

Spiral-wound cartridges are inserted ia series into cylindrical pressure vessels. Feed flows parallel to the membrane surfaces ia the channel defined by the mesh spacer which acts as a turbulence promoter. Permeate flows into the center permeate-withdrawal tube which is sealed through the housing end caps. 

Spiral Wound. A spiral-wound cartridge has two flat membrane sheets (skin side out) separated by a flexible, porous permeate drainage material,... 

In a study of the bioaccumulation of metals as colloid complexes and free ions by the marine brown shrimp, Penaeus aztecus [29] the colloids were isolated and concentrated from water obtained from Dickinson Bayou, an inlet of Galveston Bay, Texas, using various filtration and ultrafiltration systems equipped with a spiral-wound 1 kDa cutoff cartridge. The total colloidal organic carbon in the concentrate was found to be 78 lmgdm 3. The shrimps were exposed to metals (Mn, Fe, Co, Zn, Cd, Ag, Sn, Ba and Hg) as radiolabelled colloid complexes, and free-ionic radiotracers using ultrafiltered seawater without radiotracers as controls. The experiments were designed so that the animals were exposed to environmentally realistic metal and colloid concentrations. 

R. Prasad, C.J. Runkle and H.F. Shuey, Spiral-wound Hollow Fiber Cartridge and Modules Having Flow Directing Baffles, US Patent 5,352,361 (October, 1994). 

A simplified flow scheme for a brackish water reverse osmosis plant is shown in Figure 5.24. In this example, it is assumed that the brackish water is heavily contaminated with suspended solids, so flocculation followed by a sand filter and a cartridge filter is used to remove particulates. The pH of the feed solution might be adjusted, followed by chlorination to sterilize the water to prevent bacterial growth on the membranes and addition of an anti-sealant to inhibit precipitation of multivalent salts on the membrane. Finally, if chlorine-sensitive interfacial composite membranes are used, sodium sulfite is added to remove excess chlorine before the water contacts the membrane. Generally, more pretreatment is required in plants using hollow fiber modules than in plants using spiral-wound modules. This is one reason why hollow fiber modules have been displaced by spiral-wound systems for most brackish water installations. 

In this pilot plant the UF pretreatment system is arranged in 2 trains, each housing 3 modules (PAN HF membranes, nominal pore size of 0.02 (im, MWCO 50 000, total effective surface area of 30 m2). Raw seawater (samples from Qingdao Jiaozhou Bay, the Yellow Sea of China) was first passed into a cartridge sand filter and successively feed to UF system, the UF permeate was then pumped to the RO system (spiral-wound composite polyamide) (Figure 12.1). 

FIGURE 5 Membrane module design, (a) Spiral-wound (Koch Membrane Systems) (b) hollow-fiber (Du Pont) (c) tubular (generic) (d) plate-and-frame (c) pleated cartridge (Millipore). [Figure 2(d) from Strathmann and Chmiel (1985)]. 

Wang KL and Cussler EL, Baffled membrane modules made with hollow fiber fabric. Journal of Membrane Science 1993, 85, 265-278. Prasad R, Runkle CJ, and Shuey HF, Method of making spiral-wound hollow fiber membrane fabric cartridges and modules having flow-directing baffles, US Patent 5,264,171, 1993. 

Prasad R, Runkle CJ, and Shuey HP, Spiral-wound hollow fiber membrane fabric cartridges and modules having flow directing baffles, US Patent 5,352,361, 1994. 

Figure 32.11 shows a scheme of the RO plant for the treatment of the Cs-contaminated liquids. It was equipped with two kinds of spiral wound reverse osmosis membranes high-pressure (HP) and low-pressure (LP) membranes. Before flowing through the membranes, the feed was pretreated using 5 pm sleeve hlters and 0.45 pm cartridge hlters. 

Figure 1.33 Schematic diagram showing membrane modules presently used in industrial separation processes (a) pleated membrane filter cartridge (b) plate-and-frame membrane module (c) spiral wound membrane module (d) tubular membrane module (e) capillary membrane module (f) hollow fiber membrane module.

The UF membranes are protected from yarn fibers by a vibrating screen filter and 20 to 50 n cartridge filters. This makes possible the use of spiral wound modules which have a life of 24 to 30 months. The desizer waste effluent usually contains between 0.5 and 1.5% PVA. The UF concentrates this PVA up to 10% for direct use in the slasher. This final concentration is monitored and automatically controlled by an in-line refractometer. A small amount of desizer waste is purged to drain to prevent the buildup of low MW solutes. 

Chlorine has been added to the feedwater upstream of reverse osmosis pretreatment. However, since chlorine will depolymerize the polyurea membrane barrier layer in the spiral wound element, with subsequent loss of desalination properties, the chlorine is removed in the pretreatment system dechlorination basin. This removal is chemically accomplished by the addition of sodium bisulfite. The chlorine level in the influent and effluent to the dechlorination basin is continuously monitored. The feedwater is then transferred from the dechlorination basin to the cartridge filter feed pumping station by gravity flow and it is then pumped to the cartridge filters. 

The membrane shapes described are usually incorporated into compact commercial modules and cartridges. The four more common types of modules are (1) plate-and-frame, (2) spiral-wound, (3) tubular, and (4) hollow-fiber. Table 9.2 is a comparison of the characteristics of these four types of modules. The packing density refers to the surface area per unit volume of module, for which the hollow-fiber modules are clearly superior. However, hollow-fiber modules are highly susceptible to fouling and very difficult to clean. The spiral-wound module is very popular for most applications because of its low cost and reasonable resistance to fouling. 

In the spiral-wound system, membranes glued together at the ends and separated by spacers (that provide flow channels to the feed and permeate) are layered and wound around a central porous tube several times, thus forming a multilayered and cylindrical module. The feed mixture flows axially into the channels and the permeate flows spirally into a central porous tube and out of the system. A spiral-wound module has at least twice the packing density of a plate-and-frame module. Several spiral-wound modules can be lined up in series forming a cartridge system. 

Tangential flow filtration regenerated cellulose Prep/Scale Spiral Wound TFF-6 cartridge, Prep/Scale Holder, and peristaltic pump (Millipore Corporation). 

Concentrate bacterial supernatant to a final volume of 1/20 of the initial volume by tangential flow filtration using a regenerated cellulose Prep/Scale Spiral Wound TFF-6 cartridge, a Prep/Scale Holder, and a peristaltic pump at a flow rate of... 

Dechlorinated and softened water flows to the RO skid through a 5.0-nm (nominal pore size) cartridge filter. The cartridge filter removes resin fines, particles and complexed colloids necessary to protect the RO membranes from particulate fouling. The RO membranes are thin-film composite (TFC) polyamide RO membranes (20 cm diameter X 100 cm long spiral wound elements) with rejection 99%. 

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