Tangential-flow module membranes

Cross-flow The flow of fluid across a membrane surface, parallel to its surface or tangential flow. These modules have one irflet (feed) and two outlets (concentrate and permeate). This is in contrast to dead-end modules. 

The two sequentially connected modules are composed of Berghof mbular membranes, which allow a tangential flow through their interior. Each module is formed of 31 tubes of 10 mm diameter. 

The experimental setup is shown in Figure 1. It comprises a cell recycle membrane bioreactor, measuring equipment and sensors, and an online monitoring and control system. The membrane reactor consists of a stirred vessel with an effective volume of 0.45 L, coupled to a membrane module. The contaminated water is pumped tangentially along the membrane surface with a cross-flow velocity of 1 m/s, generating two streams a permeate stream free of cells (treated water), and a retentate stream (with cells) which is... 

Figure 12.5 Different membrane modules used in MD (a) a Lewis ceU, (b) flat-sheet or tangential-flow module, (c) hollow-fiber module, and (d) a thin channel module.

The factors to consider in the selection of crossflow filtration include the flow configuration, tangential linear velocity, transmembrane pressure drop (driving force), separation characteristics of the membrane (permeability and pore size), size of particulates relative to the membrane pore dimensions, low protein-binding ability, and hydrodynamic conditions within the flow module. Again, since particle-particle and particle-membrane interactions are key, broth conditioning (ionic strength, pH, etc.) may be necessary to optimize performance. 

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