Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
  • B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
  • B01D61/025—Reverse osmosis; Hyperfiltration
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
  • B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
  • B01D61/025—Reverse osmosis; Hyperfiltration
  • B01D61/026—Reverse osmosis; Hyperfiltration comprising multiple reverse osmosis steps
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
  • C02F1/441—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by reverse osmosis
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2311/00—Details relating to membrane separation process operations and control
  • B01D2311/13—Use of sweep gas
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2311/00—Details relating to membrane separation process operations and control
  • B01D2311/25—Recirculation, recycling or bypass, e.g. recirculation of concentrate into the feed
  • B01D2311/253—Bypassing of feed
  • B01D2311/2531—Bypassing of feed to permeate side
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2313/00—Details relating to membrane modules or apparatus
  • B01D2313/08—Flow guidance means within the module or the apparatus
  • B01D2313/083—Bypass routes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2317/00—Membrane module arrangements within a plant or an apparatus
  • B01D2317/02—Elements in series
  • B01D2317/025—Permeate series
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
  • C02F2103/08—Seawater, e.g. for desalination
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
  • Y02A20/00—Water conservation; Efficient water supply; Efficient water use
  • Y02A20/124—Water desalination
  • Y02A20/131—Reverse-osmosis

Definitions

• the present invention relates to the field of the purification of a liquid by passage through membranes.
• the present invention relates to the field of desalination of water, in particular for example seawater.
• Reverse osmosis is one of the processes used, especially for desalination of seawater. This process is extensively described in the literature (for example in the Degrémont Water Survey).
• Reverse osmosis is a system for purifying water by passing it through a semi-permeable membrane which preferentially retains the dissolved compounds while allowing water to pass under the effect of the pressure applied.
• the disadvantages of reverse osmosis are: the lifetime of the membranes (usually about 3 to 5 years) water losses: indeed, the concentrate that contains all the salts that have not crossed the membrane or membranes contains too much salt and represents a loss; the energy consumed by the pressurizing pump: the applied pressure must be greater than the osmotic pressure.
• the osmotic pressure is about 29 bar and the pressure usually applied to cause a flow of reverse osmosis is usually of the order of 50 to 60 bars;
• US Pat. No. 6,187,200 describes a device using reverse osmosis to desalt seawater.
• the water to be desalinated is injected under pressure (by a pump) into a first stage of which outputs a first diluted stream and a first concentrated stream.
• This first concentrated stream is injected under pressure (by a pump) into a second stage which in turn exits a second diluted stream and a second concentrated stream.
• the second flow diluted and mixed with the first diluted stream and the second concentrated stream is used in an energy recovery system.
• An object of the invention is to improve the methods and devices known for the purification of water or other liquids by reverse osmosis.
• one of the objects of the invention is to propose a liquid purification system and method that optimizes energy consumption, even without resorting to a mechanical recovery device.
• Another object of the invention is to provide a system and a method that are simple to implement and inexpensive.
• the system according to the invention uses reverse osmosis and a flow distribution in a particular way to purify water at a lower pressure than that usually used, which has the effect of reducing the energy consumption and allowing a more rudimentary construction that optimizes the costs of building the system.
• the use of the system according to the invention is particularly ideal for the desalination of seawater.
• One of the principles of the invention is to carry out the purification in several stages, the first stage being dedicated to a predilution of the flow of raw water.
• the predilution is carried out by feeding the semi-permeable membrane not only on the concentrate side (side A), but also on the permeate side (side B) with a liquid of the same concentration or a concentration close to to separate.
• the concentration of compounds to be separated is then similar on both sides of the membrane.
• the osmotic pressure is greatly reduced and the pressure to be applied to cause a flow of water through the membrane is greatly reduced.
• the liquid thus obtained on the permeate side (side B) is a mixture between a highly charged portion of solute that comes from the feed and the liquid with very little solute that has passed through the membrane.
• the resulting average concentration is highly diluted relative to the raw water supply and can be easily processed at medium pressure in a conventional reverse osmosis system.
• the system according to the invention also functions with liquids of different concentration
• the system according to the invention can be mounted in combination (in series and / or in parallel) with each other and / or with other conventional reverse osmosis stages.
• the overall energy consumption of a system comprising a predilution stage implementing the principle of the invention is significantly reduced.
• a mechanical energy recovery system is an additional possibility to optimize energy consumption.
• Figure 1 shows a first embodiment
• Figure 2 shows a second embodiment.
• Figure 3 shows a third embodiment.
• Figure 4 shows a fourth embodiment.
• a liquid for example salt water with a concentration of 36 g / l
• a separation element 3 which uses the principle of reverse osmosis.
• the liquid is separated into two flows, one of the flows arriving directly in the separating element (B side) and the other flow being pressurized, for example by a pump 4 or other equivalent means, before entering the separating element on the other side of the membrane (side A).
• a pump 4 or other equivalent means for example by a pump 4 or other equivalent means
• the pump 3 is placed upstream of the separation of the fluid flows and a pressure reducer 7 is then added to the feed on the B side in order to obtain a pressure difference in the separating element 2 according to the principle of reverse osmosis.
• a pressure reducer 7 is then added to the feed on the B side in order to obtain a pressure difference in the separating element 2 according to the principle of reverse osmosis.
• FIG. 4 a two-stage embodiment of the device according to the invention is shown.
• this mode (on the left of the figure) there is represented as a first stage a processing device corresponding to that of FIG. 1 (with the same references) and the description made above of this mode applies in a corresponding.
• This first stage which is used as a predilution stage, is followed downstream of a second dilute liquid treatment stage, comprising a pressurizing means 4 '(for example a pump), a separation element 3' (with the chambers A 'and B') providing on the one hand a concentrated liquid 5 'and on the other a diluted liquid 6'.
• a pressurizing means 4 ' for example a pump
• a separation element 3' with the chambers A 'and B'
• the first stage used in the mode of FIG. 4 can be that of FIG. 1, or 2 or 3 in an equivalent manner and FIG. 4 only serves to illustrate an embodiment possibility.
• Other possibilities may include a cascade of several successive elements.
• the invention can be used for other applications than desalination of water and for liquids other than water.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Water Supply & Treatment (AREA)
• Nanotechnology (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Life Sciences & Earth Sciences (AREA)
• Hydrology & Water Resources (AREA)
• Environmental & Geological Engineering (AREA)
• Organic Chemistry (AREA)
• Separation Using Semi-Permeable Membranes (AREA)

Applications Claiming Priority (2)

Publications (1)

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• 2008
  • 2008-06-09 EP EP08763260A patent/EP2158024A1/de not_active Withdrawn
  • 2008-06-09 CN CN200880018843A patent/CN101720249A/zh active Pending
  • 2008-06-09 US US12/663,318 patent/US20100294718A1/en not_active Abandoned
  • 2008-06-09 WO PCT/IB2008/052266 patent/WO2008149324A1/fr active Application Filing
  • 2008-06-09 AU AU2008259415A patent/AU2008259415A1/en not_active Abandoned
  • 2008-06-09 JP JP2010510948A patent/JP2010528842A/ja active Pending
• 2009
  • 2009-12-07 IL IL202575A patent/IL202575A0/en unknown

Non-Patent Citations (1)

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