Membrane cross-flow

FIG. 22-65 Characteristic curve for flux as a function of pressure for cross-flow membrane processes limited by mass transfer at the membrane. 

Cassettes Cassette is a term used to describe two different cross-flow membrane devices. The less-common design is a usually large stack of membrane separated by a spacer, with flow moving in parallel across the membrane sheets. This variant is sometimes referred to as a flat spiral, since there is some similarity in the way feed and permeate are handled. The more common cassette has long been popular in the pharmaceutical and biotechnical field. It too is a stack of flat-sheet membranes, but the membrane is usually connected so that the feed flows across the membrane elements in series to achieve higher conversion per pass. Their popularity stems from easy direct sc e-up from laboratoiy to plant-scale equipment. Their hmitation is that fluid management is inherently veiy hmited and inefficient. Both types of cassette are veiy compact and capable of automated manufacture. 

Also included are sections on how to analyze mechanisms that affect flux feature models for prediction of micro- and ultrafiltration flux that help you minimize flux decline. Descriptions of cross-flow membrane filtration and common operating configurations clarify tf e influence of important operating parameters on system performance. Parameters irdlucnc irxj solute retention properties during ultrafiltration arc identified and discussed or treated in detail. 

S.J. Peng and R.A. Williams Controlled Production of Emulsions Using a Cross-flow Membrane. Part. Part. Syst. Charact. 15, 21 (1998). 

The technology is a combination of biodegradation, adsorption onto activated carbon, and microfiltration. It uses microbes grown on active powdered carbon as a prefilter and to degrade organics and a cross-flow membrane filter to remove biomass, viruses, and suspended impurities. 

Cross-flow membrane emulsification (see Section 15.6.1 and Figure 15.9)... 

Droplet sizes and important proeess parameters The properties of the membrane are very important in this process. The membrane should have a relatively narrow pore size distribution, just as with cross-flow membrane emulsification, and it should be wetted by the phase that should be the continuous phase. 

A few food products have been on the market using cross-flow membrane emulsification. The method can make emulsions that have small droplets with a narrow size distribution. Thus, it is possible to make sauces with lower oil content than with conventional emulsification techniques. The technique of cross-flow emulsification is clearly the best developed process for small-scale, high-value applications it is an attractive process. 

Peng, S.J. and Williams, R.A. (1998). Controlled produetion of emulsions using a cross-flow membrane. Part I droplet formation from a single pore. Trans. Inst. Chem. Eng. 76,... 

Filtrations for CWM were carried out with a cross flow membrane separation system. It consists of a cross flow membrane module, a feed pump, a recirculation pump and process pipes. The feed steam contained 1000 ppm PMMA with a mean particle size of 0.8... 

The objective in membrane design is to pack as much permeation surface area into as small a space as possible to minimize operation requirements. Depending on the application, various membrane designs are used, such as flat sheet, disc tube, hollow fiber, spiral wound, and ceramic (17). Module design has a measurable effect on the hydrodynamic performance of the cross-flow membrane device. The advantages and disadvantages of different membrane modules are summarized in Table 1. 

G. Catapano, G. lorio, E. Drioli, and M. Filosa, Experimental analysis of a cross-flow membrane bioreactor with entrapped whole cells Influence of trans-membrane pressure and substrate feed concentration on reactor performance, J. Membrane Sci 55 325 (1988). 

FIGURE 6.26 Schematic representation of cross-flow membrane emulsification. 

Gijsbertsen-Abrahamse AJ, van der Padt A, and Boom RM. Stams of cross-flow membrane emulsification and outlook for industrial appUcation. J. Membr. Sci. 2004 230 149-159. 

Bacchin, P., Si-Hassen, D., Starov, V., Clifton, M.J., and Aimar, P., A unifying model for concentration polarization, gel-layer formation and particle deposition in cross-flow membrane filtration of colloidal suspensions, Chem. Eng. Sci., 57, 77, 2002. 

Green, W.A., Innovative Cross-Flow Membrane System for Volume Reduction of Mixed Waste, in http /www.oml. gov/divisions/ctd/ESP/97tasks/task33.htm, accessed on 14.08.2002. 

KyUdnen H, Pirkonen P, Nystrdm M, Nuortila-Jokinen J, and Grdmoos A. Experimental aspects of ultrasonicaUy enhanced cross-flow membrane filtration of industrial wastewater. Ultrasonics Sonochemistry 2006 13(4) 295-302. 

Heal JM, Bailey G, Helphingstine C, Thiem PA, Leddy JP, Buchholz DH, Nusbacher J. Non-centrifugal plasma collection using cross-flow membrane plasmapheresis. Vox Sang 1983 44(3) 156-66. 

Solomon, B. A. Colton, C. K. Friedman, L. 1. Castino, F. Wiltbank, T. B. Martin, D. M. "Microporous Membrane Filtration for Continuous-Flow Plasmapheresis" In Ultrafiltration Membranes and Applications Vol. 3 of Polymer Science and Technology Cooper, A. R., Ed. Henum Press New York, N.Y., 1980, pp 489-505. Zydney, A. L. "Cross-flow membrane plasmapheresis an analysis of flux and hemolysis PhD Thesis, Massachusetts Institute of Technology, 1985. 

Cross-flow filtration (CFF) also known as tangential flow filtration is not of recent origin. It began with the development of reverse osmosis (RO) more than three decades ago. Industrial RO processes include desalting of sea water and brackish water, and recovery and purification of some fermentation products. The cross-flow membrane filtration technique was next applied to the concentration and fractionation of macromolecules commonly recognized as ultrafiltration (UF) in the late 1960 s. Major UF applications include electrocoat paint recovery, enzyme and protein recovery and pyrogen removal. 

Cross-flow membrane filters made from inorganic materials, primarily ceramics and metals, utilize entirely different manufacturing processes compared with their polymeric counterparts. Although carbon membranes... 

Traditional fermentation generally involves many process steps which are inefficient and uneconomical in terms of utilization of raw materials,recovery of product, and energy consumption. Continuous cross-flow membrane micro-filtration and ultrafiltration, when correctly introduced, have been shown to improve this process significantly. 

Figure 2.47 Cross-flow membrane cassette (two layers of membrane enclosing inner collection screen) and flow-channel spacer.

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