Liquid purification or separation – Processes – Liquid/liquid solvent or colloidal extraction or diffusing...
Patent
1997-01-09
1999-09-14
Fortuna, Ana
Liquid purification or separation
Processes
Liquid/liquid solvent or colloidal extraction or diffusing...
21033175, 210175, 210653, B01D 6100
Patent
active
059518715
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
This invention relates to a method and apparatus for separating liquid-liquid mixtures and relates particularly to separation of liquid-liquid mixtures which may be temperature sensitive, flammable, toxic, or otherwise unsuitable, for separation using heat distillation. The method and apparatus is particularly suitable for separating undesirable liquid components from bio-fluids, such as blood plasma.
A well known liquid-liquid separation technique involves distillation whereby liquids of different boiling points can be separated. For liquids having close boiling points, separation efficiency is enhanced by using distillation columns. Distillation is unsuitable for many types of liquids including temperature-sensitive liquids (i.e., bio-fluids, certain liquid food products), highly flammable liquids, such as the low molecular weight ethers, liquids which have toxic vapours, or liquid-liquid mixtures where separation must be done quickly.
Membrane separation is used where separation of liquid mixtures by distillation is undesirable. Membrane separation is more commonly used to remove liquids from a liquid/dissolved solid mixture. The methodology behind membrane separation can be very complex and can include osmotic pressure, relative vapour pressures, diffusion co-efficient, molecular size, molecular shape and molecular charge.
A known type of liquid-liquid separation using membranes involves a combined permeation/evaporation method. A liquid-liquid mixture is passed into a first chamber which is separated from a second chamber by a membrane. A pressure differential is applied across the membrane and by correct choice of the membrane, a particular component in the liquid-liquid mixture will permeate across the membrane selectively in preference to other components. This type of membrane separation is described in European patent specification 0346739 and Japanese patent specification 1-159007. While this technique allows separation of temperature-sensitive components, a disadvantage with the technique is that it is relatively slow, making it less suitable for separation of mixtures which are unstable over time, or which must be treated quickly. For instance, slow membrane separation techniques are not suitable for purification of bio-fluids which must be removed from a patient's body, purified and re-introduced into the patient's body, as quickly as possible. The slow membrane separations are also unsuitable in many pharmaceutical, medical and beverage applications where it is desirable to achieve separation as quickly as possible.
SUMMARY OF THE INVENTION
The present invention provides a method and an apparatus which can at least partially separate liquid from a liquid-liquid mixture in a manner which may overcome the abovementioned disadvantages. The method utilizes a membrane to separate liquid-liquid mixtures and is characterized by converting the initial liquid-liquid mixture into a fine spray before contacting the membrane. The combination of membrane separation with initial atomization of the liquid-liquid mixtures can produce superior results.
In one form, the invention resides in a method for separating a liquid from a liquid-liquid mixture, the method comprising the steps of contacting the liquid-liquid mixture against one side of a separating membrane in the form of a spray.
The liquid-liquid mixture may be atomised into a fine droplet spray by any suitable method or apparatus. A nozzle may be used to convert the liquid mixture into a spray of fine droplets. The spray may be generated within a gas flow and this may be achieved via a venturi type device. The gas may be an inert or reactive gas and may include compressed air, steam, nitrogen, carbon dioxide, sulphur dioxide, ethylene oxide, fluorine, hydrogen, argon, or mixtures thereof. The gas or gas mixture may be able to carry an electric charge.
The membrane may comprise a rigid or flexible membrane. A rigid perforated/porous ceramic or metal membrane may be used. An alternative form of membrane is a flexible po
REFERENCES:
patent: 3405058 (1968-10-01), Miller
patent: 3827561 (1974-08-01), Serfass et al.
patent: 4222871 (1980-09-01), Lefeuvre
patent: 5062927 (1991-11-01), Stout
patent: 5078755 (1992-01-01), Tozaua et al.
patent: 5537911 (1996-07-01), Ohlrogge et al.
Patent Abstracts of Japan, C-218, p. 18, JP,A 57-1009742 (Asahi Kasei Kogyo K.K.), Jan. 5, 1984.
Derwent Abstract Accession No. 94-329166/41 Class E 17, JP, A, 06254354 (Mitsubishi Kasei Corp) Sep. 13, 1994.
Fortuna Ana
The University of Queensland
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