Spiral wound membrane modules flow characteristics

First multi-leaf spiral wound membrane module developed by Don Bray and others at Gulf General Atomic, under US Patent no. 3,417,870, "Reverse Osmosis Purification Apparatus," December, 1968. A multi-leaf spiral configuration improves the flow characteristics of the RO module by minimizing the pressure drop encountered by permeate as it spirals into the central collection tube. 

Characteristics of membrane modules are summarised in Table 1.12. The spiral wound (SW) module shown in Figure 1.18 is used in all RO and NF applications. The RO hollow-fibre (FIF) module, similar to the one shown in Figure 1.19, is now manufactured by only by Toyobo, and is used for seawater desalination. UF HF membrane (see Figure 1.3) was used extensively in the dairy industry, but it has largely been replaced by SW modules. However, cross-flow HF modules are commorJy used in food processing and industrial wastewater treatment [18, 31]. 

The configuration (flat sheet, mbular modules, hoUow fibers, plates units, and spiral wound) also affects membrane performance. Good membrane performance with respect to permeate flow rate and the retention of the desired solute should be balanced with respect to its characteristics such as propensity for fouUng, cost, ease of cleaifing, and substimtion [2,6]. 

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