Uniform Transmembrane Pressure Filtration

In the conventional cross-flow filtration described in previous section, the transmembrane pressure (TMP) along the feed flow channels varies substantially from the feed end of the module to the exit or retentate end. This 

Nonuniform TMP values over the filtration surface area may cause substantial (up to 50%) reduction in the product recovery in the permeate. A novel approach to improving the flux and/or product recovery utilizes the concept of a uniform transmembrane pressure. lf This is achieved by varying the permeate side pressure with an independent recirculation pump to adjust the TMP to a constant value. A schematic of the UTP and conventional cross-flow configuration is shown in Figs. 11 and 12, respectively. The TMP profiles for the two operational modes are shown in Fig. 13. Flux improvements up to 500% have been achieved compared with the conventional cross-flow mode in many important food, beverage and biotechnology applications. 

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It is interesting to note that the problem of operation with large pressure differences between the feed/retentate side and the permeate compartment of membrane filtration modules was identified long ago. The concept of operation under low uniform transmembrane pressure (UTMP) was pioneered and first... 

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