Hyperfiltration. Reduction of Concentration Polarization of Dynamically Formed Hyperfiltration Membranes by Detached Turbulence Promoters

Thomas, David G.; Watson, J.S.

doi:10.1021/i260027a015

Cited by 17 publications

(7 citation statements)

References 4 publications

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“…A more detailed review of convection promotion is given by Pitera (1972). Specific applications to reverse osmosis desalination include studies by Thomas (1968Thomas ( , 1970, while Peri and Dunkley (1971) have examined the use of convection promotion to enhance membrane separation of whey protein from aqueous solution.…”

Section: Analysis Of Membrane Transportmentioning

confidence: 99%

“…This problem is easily solved by using "streamlined" shapes, such as spheres spaced along a central rod, or inserts which present minimal surface area in the plane normal to the tube axis. In the latter class of inserts are the "twisted tapes" used by several investigators for heat transfer promotion (e.g., Kidd, 1969), and by Thomas (1968) in desalination membranes.…”

Section: Analysis Of Membrane Transportmentioning

confidence: 99%

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Convection Promotion in Tubular Desalination Membranes

Pitera¹,

Middleman²

1973

Ind. Eng. Chem. Proc. Des. Dev.

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The use of a Kenics Static Mixer, a form of twisted tape insert, for convection promotion within a tubular desalination membrane, is studied for Reynolds numbers in the range 1 0-1 500. The polarization ratio is significantly reduced, leading to improvement of permeate quality and an increase in permeate flux. means of increasing the efficiency of a reverse osmosis desalination system lies in reducing the effects associated with concentration polarization. Polarization is caused by the rejection of solutes at the membrane/solution interface. Because of the high osmotic pressure typical of salts, polarization causes a reduction of water flux, or, correspondingly, it leads to the requirement of a very high operating pressure to mainc = molar concentration of solution, g-mol/cm3

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Section: Analysis Of Membrane Transportmentioning

confidence: 99%

Section: Analysis Of Membrane Transportmentioning

confidence: 99%

Convection Promotion in Tubular Desalination Membranes

Pitera¹,

Middleman²

1973

Ind. Eng. Chem. Proc. Des. Dev.

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“…In the present study flow conditions were varied by changing the flow rate and by inserting turbulence promoters into the tubular membranes. Thomas and Watson (1968) studied the influence of turbulence promoters positioned away from the membrane surface on performance of dynamically formed reverse osmosis membranes. Selection of the turbulence promoters was based on an earlier study of effects of the devices on forced convection heat transfer (Thomas, 1967).…”

Section: Introductionmentioning

confidence: 99%

REVERSE OSMOSIS OF COTTAGE CHEESE WHEY 2. Influence of Flow Conditions

Peri¹,

Dunkley²

1971

Journal of Food Science

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Flow conditions in tubular, cellulose-acetate reverse osmosis membranes were varied by changing the flow rate and by inserting turbulence promoters (rods with intermittently-spaced rings cemented to them) in the tubes. In general, increasing the flow velocity increased the permeation rate. Turbulence promoters were most effective in increasing permeation rate under conditions that, in their absence, permitted fouling of the membrane surface by macrosolutes from the feed. When the feed contained macrosolutes, increasing the flow velocity or use of turbulence promoters increased retention of lactose and potassium.Modifying the flow conditions to increase turbulence improves performance of reverse osmosis membranes by increasing both permeation rate and retention.

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“…Significant increases in dynamic membrane permeability have been observed in exploratory studies (Thomas and Watson, 1968) of the effect of detached spiral turbulence promoters on membrane performance. In these studies, the turbulence promoters were located in the downstream half of a porous tube, otherwise the operating conditions were the same.…”

mentioning

confidence: 99%

“…A potentially attractive turbulence promoter design which meets many of the "ideal" requirements outlined above is the "detached" promoter in which the promoter is supported away from the surface. Fundamental studies of such promoters have been reported previously (Thomas and Kraus, 1964;Thomas, 1965;Watson and Thomas, 1967) as have exploratory studies aimed at reduction of concentration polarization at dynamically formed hyperfiltration membranes (Thomas and Watson, 1968).…”

mentioning

confidence: 99%