Liquid purification or separation – Processes – Liquid/liquid solvent or colloidal extraction or diffusing...
Patent
1994-11-21
1997-04-15
Fortuna, Ana
Liquid purification or separation
Processes
Liquid/liquid solvent or colloidal extraction or diffusing...
21032175, 21032184, 210346, 210484, 210232, 210456, 2104331, B01D 6100, B01D 6300
Patent
active
056206054
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The invention relates to a system and apparatus for use in the system which contains membrane cassettes and which is useful for separations in which the transmembrane pressure may be low.
BACKGROUND OF THE INVENTION
Membrane separation processes are becoming increasingly popular for the separation of a feed stream into two streams, the retentate stream which is rich in a component which does not selectively pass through the membrane and a permeate stream which is rich in components which selectively pass through the membrane. Examples of such processes include gas separations, such as the separation of oxygen from nitrogen, reverse osmosis processes in which dissolved salts are removed from water, processes for converting surface water to potable water by removing particulates and high molecular weight species such as bacteria, and pervaporation processes in which volatile components of a liquid stream selectively permeate through a membrane.
In order for a membrane separation to be effective there must be some driving force. The two most common driving forces are based on a concentration or a pressure differential from one side of the membrane to the other. When pressure is a driving force the pressure is higher on the feed side of the membrane. When concentration is the driving force, the concentration of the species which preferentially permeates is typically higher on the feed side.
Recently, some plate and frame membrane separation devices have been disclosed (Japan Kokai 41-10090 (application no. 2,229,631) published 10 Apr. 1992; Japan Kokai 47023 (application no. 2,107,991) published 10 Jan. 1993 and Japan Kokai 4187222 (application no. 2,319,141) published 3 Jul. 1992) which have suction pumps on the permeate side of a plate and frame membrane. The pressure differential can be created by the suction pumps. In such devices each membrane element is a plate with a membrane attached to it wherein each plate has a permeate flow channel on the permeate side of the membrane. The suction pump is connected individually to each plate. The membrane plates are carefully separated from one another to allow turbulent flow along the surface of each membrane to facilitate removal of solids which tend to stick to the retentate side of the membrane. The plates are generally placed vertically in a tank. The turbulent flow is created by pumps, blades or air blown through aeration pipes placed near the membrane services.
U.S. Pat. No. 5,084,220 discloses apparatus including membrane cassette which is useful in converting large amounts of surface water into potable water. The disclosed apparatus comprises an array of cassette frames separated by intermediate plates. The cassette frames and intermediate plates are provided with high pressure seals so that when the cassette frames and intermediate plates fit together a pressure tight seal is formed. The whole array of cassette frames and intermediate plates form a pressure vessel when end plates which also seal with the end cassette frames are used. The array of cassette frames intermediate plates and end plates is adapted to be clamped together in its longitudinal direction and loosened, as required, to remove any selected cassette frame. Each cassette frame contains a filtration unit comprising a stack of membranes, in which a first flow passage system is provided which connects two free zones within the cassette frame, said free zones being so connected as to establish a series, parallel or combined series and parallel pattern of fluid flow from the feed inlet to a concentrate outlet. In each stack of membranes is a second system of flow passages which is isolated from the first system and serves to conduct the stream that permeates through the membranes to at least one outlet from each filtration unit. This system is designed to operate at relatively high pressures. The system has been carefully designed to allow the end plates cassette units and intermediate plates to fit together in a fashion such that a pressure case is formed about the
REFERENCES:
patent: 3591493 (1971-07-01), Zeineh
patent: 4159250 (1979-06-01), Schnell
patent: 4176069 (1979-11-01), Metz et al.
patent: 4430218 (1984-02-01), Perl et al.
patent: 4749476 (1988-06-01), Storkebaum et al.
patent: 5035799 (1991-07-01), Rosberg et al.
patent: 5084220 (1992-01-01), Moller
patent: 5192434 (1993-03-01), Moller
patent: 5192456 (1993-03-01), Ishida
patent: 5217612 (1993-06-01), Ondrick
patent: 5275725 (1994-01-01), Ishii et al.
Fortuna Ana
The Dow Chemical Company
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