Membrane contactors module design

Referring to the membrane module design, it has a big influence on the membrane-contactor efficiency, because it affects the pressure drops of the streams (and, thus, the operating pressures and flowrates), and their fluidodynamic (which means the mass and heat transport resistances of the phases). Furthermore, for hollow-fiber modules it is essential to ensure a uniform packing, in order to have... 

The design of the first commercial modules has allowed the commercial application of membrane contactors for some specific operations. This is the case of the Membrana-Charlotte Company (USA) that developed the LiquiCel modules, equipped with polypropylene hollow fibers, for the water deoxygenation for the semiconductor industry. LiquiCel modules have been also applied to the bubble-free carbonation of Pepsi, in the bottling plant of West Virginia [18], and to the concentrations of fruit and vegetable juices in an osmotic distillation pilot plant at Melbourne [19]. Other commercial applications of LiquiCel are the dissolved-gases removal from water, the decarbonation and nitrogenation in breweries, and the ammonia removal from wastewater [20]. 

Stanojevic M, Lazarevic B, and Radic D. Review of membrane contactors designs and applications of different modules in industry. FME Trans. 2003 31 91-98. 

When hydrophobic membranes are used (olefins are preferred because of their low cost), the aqueous absorbent cannot penetrate through the pores and the membrane is gas filled whereas if hydrophilic membranes are employed, the membrane is liquid filled (Figures 38.1 and 38.2). Latter situation is preferred only if the reaction between the gaseous species and the absorbent solution is fast or instantaneous if not, it is better to work with a gas-filled membrane, to reduce mass-transfer resistances. The module design and flow configuration also play an important role in defining the membrane contactors efficiency. This aspect is discussed in detail in Section 38.5. 

Patents on new module designs have been recently presented. Nitto Denko (Japan) patented a spiral wound design for membrane contactor applications [51]. The system includes a central feed pipe around which one or more membranes are wound. Tests on water ozonation demonstrated that it is possible to achieve a concentrahon of ozone 10% higher than in hollow hber. 

Membrane module design for contactor devices (adapted from Stanojevic et a ., 2003) (a) hollow fibre wound helically around a central core (b) hollow fibre wound helically around a central core (c) hollow fibre wound mounted diagonally in an open-ended box (e) rectangular module containing two baffles (f) baffled cylindrical module. 

This chapter provides a state-of-the-art review of HFMST including a general review of hollow fiber membrane contactors, operating principles, design consideration, commercial availability of hollow fiber membrane, and module for scale-up and large-scale studies. Application of HFMST in pharmaceutical, biotechnological, gas absorption and stripping, wastewater treatment, and few latest studies of metal ion extraction are described in detail. 

In a general way, most of ceramic membrane modules operate in a cross-flow filtration mode [28] as shown in Figure 6.18. However, as discussed hereafter, a dead-end filtration mode may be used in some specific applications. Membrane modules constitute basic units from which all sorts of filtration plants can be designed not only for current liquid applications but also for gas and vapor separation, membrane reactors, and contactors, which represent the future applications of ceramic membranes. In liquid filtration, hydrodynamics in each module can be described as one incoming flow on the feed side gf, which results in two... 

Hydrophilic (or ion-exchange) membranes were used for designing rotating disk, creeping film, hybrid liquid membrane, and multimembrane hybrid membrane systems, hoUow-fiber LM modules. Hydrophobic membranes were used for designing hybrid liquid membrane, multimembrane hybrid system, flowing LM, hoUow-fiber contained LM, capiUary liquid membrane modules (or contactors). Below, some of these systems are referenced and described shortly. 

---