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
  • B01D61/14—Ultrafiltration; Microfiltration
  • B01D61/20—Accessories; Auxiliary operations
• • 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
  • B01D61/14—Ultrafiltration; Microfiltration
  • B01D61/18—Apparatus therefor
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D63/00—Apparatus in general for separation processes using semi-permeable membranes
  • B01D63/02—Hollow fibre modules
  • B01D63/024—Hollow fibre modules with a single potted end
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D65/00—Accessories or auxiliary operations, in general, for separation processes or apparatus using semi-permeable membranes
  • B01D65/02—Membrane cleaning or sterilisation ; Membrane regeneration
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D65/00—Accessories or auxiliary operations, in general, for separation processes or apparatus using semi-permeable membranes
  • B01D65/08—Prevention of membrane fouling or of concentration polarisation
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2201/00—Details relating to filtering apparatus
  • B01D2201/08—Regeneration of the filter
  • B01D2201/087—Regeneration of the filter using gas bubbles, e.g. air
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2313/00—Details relating to membrane modules or apparatus
  • B01D2313/18—Specific valves
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2313/00—Details relating to membrane modules or apparatus
  • B01D2313/26—Specific gas distributors or gas intakes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2315/00—Details relating to the membrane module operation
  • B01D2315/06—Submerged-type; Immersion type
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2321/00—Details relating to membrane cleaning, regeneration, sterilization or to the prevention of fouling
  • B01D2321/04—Backflushing
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2321/00—Details relating to membrane cleaning, regeneration, sterilization or to the prevention of fouling
  • B01D2321/18—Use of gases
  • B01D2321/185—Aeration
• • 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
  • C02F1/444—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by ultrafiltration or microfiltration

Definitions

• Filtration device for the treatment of water, of the submerged membrane type, including anti-backflow means from the medium to be filtered towards means for injecting a cleaning gas.
• the invention relates to the field of water treatment. More specifically, the invention relates to a device for injecting an unclogging gas into a bundle of filtration membranes immersed in a medium to be filtered.
• the filtration system comprises vertical submerged membranes grouped in modules of generally cylindrical or parallelepiped shape. Conventionally, these modules integrate flat plates or hollow fibers of organic membranes, potted at least at their lower end. The treated liquid is filtered under the effect of a pressure difference maintained between the two sides, upstream and downstream, of the membranes.
• These membranes are traditionally micro-filtration, ultra-filtration or nano-filtration membranes.
• the invention applies particularly to devices in which the membranes are arranged in a vertical position, but also applies to filtration devices in which the membranes are immersed in a horizontal position.
• These submerged membrane systems are used in particular for the treatment of drinking water, with a view to retaining pollution suspended in water or to prohibit the passage of microscopic (protozoan) animalcules, such as cryptosporidium or giardia, bacteria and / or viruses, or to retain pulverulent reagents or catalysts, such as powdered activated carbon or alumina, which have been injected into the treatment process upstream of the membranes.
• microscopic animalcules such as cryptosporidium or giardia, bacteria and / or viruses
• pulverulent reagents or catalysts such as powdered activated carbon or alumina
• This type of membrane is also used in immersion in biological membrane reactors (often called "MBR"), as a means for clarifying waste water treated with a biomass in suspension in the reactor, and as a means for preserving the biomass inside the reactor.
• MLR biological membrane reactors
• Membrane modules are often aggregated into rac s or cassettes, with a support and common connections for all modules in the rack or cassette.
• sludge a problem lies in the progressive clogging of the membranes by the materials to be filtered, called sludge, and this particularly with regard to the membranes immersed in a bioreactor containing activated sludge.
• the membranes are gradually clogged by the sludge trapped on their surface or in their thickness, or even, in the case of a severe clogging of the bundle of fibers, by plugs of sludge and / or of fibrous materials trapped by said beam.
• This clogging requires unclogging actions, often carried out by periods of back-filtration by the permeate, with or without chemical reagent, or by chemical washing of the membranes.
• an injection of a gas generally air is carried out, continuously or cyclically, at the bottom of the membrane module.
• the injected gas bubbles rise along the fiber or the plate with a speed which tends to limit the deposition of materials on the membrane, thereby reducing the clogging speed of the filtration membranes. This is due to the fact that the rise of the injected gas bubbles creates strong turbulence, more or less agitating the neighboring fibers, mechanically cleaning the flat fibers or plates by the action of the injected air, which ultimately makes it possible to delay the clogging of the membrane bundle.
• Various methods have been proposed for ensuring the injection of such an unclogging gas. According to a known technique illustrated in FIG.
• the gas is injected directly into a closed chamber 10 (using a pipe 11) located under the lower potting 12 of the hollow fiber bundles 13, the air being distributed between modules using a valve 14 or a calibrated orifice, before passing into the openings 15 formed in the lower potting bundles of fibers.
• the medium to be filtered crosses the membranes in the direction indicated by the arrow FI.
• the use of this system leads to rapid clogging of the injection openings. In fact, each time the gas injection is stopped, part of the medium to be treated enters these openings, and the sludge thus supplied is dried by the gas when the injection is resumed, which quickly causes fouling or even l closing the openings.
• the unclogging air is brought under each module via a pipe provided with perforations allowing the passage of the air.
• the air injected under the modules enters the modules, then rises inside the modules along the hollow fibers, before escaping through the sides or through similar orifices provided in the upper potting of the modules.
• the unclogging air is also brought under each module by means of pipes provided with perforations allowing the passage of air, the membrane module being here represented in a horizontal position.
• a venturi type system is provided for also distributing the flow of sludge and gas under the modules.
• a disadvantage of the gas injection mode implemented in these techniques is that the air injection openings located in the base of the membrane bundle gradually clog up due to the deposition of sludge (or large particles, fibers ... brought by the liquid to be treated), as well as in the zone 16 of mud / air mixture. Consequently, this phenomenon gradually leads to a poor distribution of the gas, unevenly distributed at the base of each module or between the various modules, and finally an acceleration of the clogging of the parts of the fiber bundle or of the flat plates badly scanned by the unclogging gas. .
• the invention also aims to overcome the drawbacks of the prior art.
• the object of the invention is to propose a filtration device intended for water treatment, of the type with membranes immersed in a medium to be filtered and including means for injecting a gas for unclogging the membranes, which removes the clogging phenomena of the injection means encountered with the solutions of the prior art.
• the invention also aims to provide such a filtration device which allows good distribution of the unclogging gas in the membrane bundles.
• the invention also aims to provide such a filtration device which is compatible with different unclogging gas injection systems.
• the invention also aims to provide such a filtration device which limits maintenance interventions or which facilitates them when they are necessary.
• Another object of the invention is to provide such a filtration device which is simple in design and easy to implement.
• Yet another objective of the invention is to provide such a filtration device which is not aggressive for the membranes.
• the clogging of the injection means being avoided, the distribution of clogging gas is then ensured with a satisfactory and almost constant distribution. It is therefore understood that the maintenance interventions aimed at unclogging the gas injection means can, thanks to the invention, be significantly reduced, or even eliminated.
• the anti-backflow means according to the invention may act directly at the level of the gas injection means or at the level of the injection openings in the filtration module, as will appear more clearly below.
• a curtain of bubbles is obtained which exerts a protective function on the membranes and prevents them from being attacked by the materials to be filtered.
• said injection means comprise at least one orifice formed in at least one nozzle for supplying said gaseous fluid
• said anti-backflow means comprising at least one material for covering said or said orifices, having at least one elastically deformable passage whose contours deviate when the pressure of said gaseous fluid exceeds a predetermined pressure in said supply tube and are contiguous when the pressure of said gaseous fluids is lower at said predetermined pressure.
• said one or more feed nozzles extend substantially horizontally under said membranes.
• the invention can therefore be adapted to devices in which the gas to be injected is brought under the filtration modules using perforated pipes, as described above with reference to FIGS. 2a and 2b.
• said covering material preferably forms a sleeve attached in leaktight manner to each of said nozzles.
• Such a sleeve indeed proves to be particularly suitable for the shape of the pipes and allows easy and quick installation and fixing.
• said one or more membranes extend substantially horizontally.
• said one or more membranes extend substantially vertically, said injection means comprising at least one opening made in the vicinity of at least one of the ends of said membranes.
• said one or more nozzles extend at least partially through said one or more openings.
• Such an embodiment therefore appears particularly suitable for filtration devices in which the filtration modules are served by a closed enclosure for unclogging gas distribution. It is therefore understood that, the nozzles equipped with their covering material extending through the injection openings, protection of the openings is obtained against clogging, this thanks to the nozzles themselves and their covering material.
• said covering material forms a cap carried by said one or more nozzles.
• nozzles these have a flush end in said space relative to said aperture (s), said aperture (s) being formed on said flush end.
• said one or more caps have a length substantially greater than that of said one or more nozzles. It is thus possible to vary the length of the cap as a function in particular of the desired pressure drop.
• nozzles these have a cylindrical portion extending in a space in the vicinity of said one or more membranes. In this case, said opening or openings are advantageously provided on the periphery of said cylindrical portion.
• said one or more cylindrical portions have a length of between approximately 20 mm and approximately 500 mm, and preferably have a length of approximately
• said cap has a length substantially equal to that of said cylindrical portion.
• said one or more caps have a length of between approximately 20 mm and approximately 200 mm, and preferably have a length of approximately 60 mm.
• said one or more caps have at least one substantially vertical slot, forming said elastically deformable passage, and preferably have, at their periphery, a plurality of regularly distributed slots.
• nozzles these have an end in the form of a dome extending in said one or said spaces formed between said membranes, said one or more orifices being formed on said dome.
• said one or more nozzles preferably have two orifices, said one or more caps having a slot extending radially between said two orifices.
• said slot extends over a length of between approximately the diameter of the base of said dome and approximately one third of said diameter. In this way it is possible to obtain a satisfactory pressure drop, and to vary it according to the characteristics of the module.
• said backflow prevention means comprise at least one valve mounted in each of said openings so as to be movable between at least two positions: - An injection position when the pressure of said gaseous fluid upstream of said valve, in the direction of injection, is greater than a predetermined pressure; - A closed position of said opening when the pressure of said gaseous fluid upstream of said valve, in the direction of injection, is less than said predetermined pressure.
• said valve or valves comprise a valve mounted movable in translation in said opening along the longitudinal axis of said opening.
• said valve is preferably coupled to elastic return means which tend to return said valve to said closed position, when the pressure of said gaseous fluid upstream, in the direction of injection, of said valve is lower than said predetermined pressure.
• said valve or valves comprise at least one elastically deformable washer mounted on a support extending coaxially with said opening.
• Such an embodiment proves to be particularly advantageous in that it combines efficiency, simplicity, reliability and durability over time.
• such an arrangement avoids the use of a return spring according to the previous embodiment.
• said backflow prevention means and / or said one or more nozzles which support them are removable. In this way, maintenance interventions are facilitated, when these are necessary.
• said anti-backflow means are made of at least one material belonging to the following group: - rubber; - silicone; - terpolymer of ethylene, propylene and a diene; - polyurethane.
• said material has a thickness of between approximately 0.5 mm and approximately 3 mm.
• the device comprises means for distributing said gaseous fluid making it possible to distribute said gaseous fluid through said anti-backflow means with a flow rate of between approximately 2.10 5 Nm 3 / s and approximately 5.10 "3 Nm 3 / s.
• said membranes are taken in at least one potting, at least at their lower end, said opening (s) being formed in said potting.
• said membranes are taken in a lower potting and in an upper potting, respectively at their lower and upper end
• said anti-backflow means are provided to cause a pressure drop of between approximately 20 cm and approximately 60 cm of water column.
• said membranes belong to the following group: - microfiltration membranes; - ultra-filtration membranes; - nanofiltration membranes.
• FIG. 1 is a schematic representation of a membrane filtration device according to the art anterior
• Figure 4 is a schematic representation of a first embodiment of the invention, according to which the unclogging gas is supplied by a perforated pipe
• - Figure 5 is a schematic representation of a second embodiment of the invention, according to which the unclogging gas is supplied by a nozzle extending between the membranes
• - Figure 5b is a view of a detail of embodiment of the device illustrated in Figure 5
• Figure 6 is a schematic representation of a third embodiment of the invention, according to which the unclogging gas is supplied by a nozzle flush with the edges of the injection opening
• - Figure 7 is a schematic representation of a fourth embodiment of the invention, according to which the unclogging gas is supplied by a nozzle having a dome extending between the membranes
• the principle of the invention resides in the fact of equipping a membrane filtration device, including means for injecting an unclogging gas, with anti-backflow means provided so that the medium to be filtered (loaded with sludge or other pollutants) cannot block the means for injecting the unclogging gas.
• these anti-backflow means comprise an elastically deformable material having passages for the unclogging gas, these passages being closed in the absence of gas pressure and open during a gas injection.
• FIG. 4 illustrates a first embodiment using such a deformable material forming anti-backflow means.
• the filtration device is of the type comprising membranes 13 (which can be microfiltration, ultrafiltration or nano-filtration membranes according to various possible embodiments) whose lower end is taken in a potting 12 having openings 15 for the passage of a cleaning gas.
• the medium to be filtered crosses the membranes 13 in a direction indicated by the arrow FI.
• the membranes can be arranged horizontally (according to a diagram similar to that illustrated in FIG. 2b), the unclogging gas being injected using a perforated pipe.
• the unclogging gas is injected using a perforated pipe 41 (or more) and a deformable material, of the type having passages as mentioned above, is attached to the perforated pipe 41.
• This deformable material is produced in the form of a sleeve 40, fitted on the pipe 41, and fixed at its ends using clamps (or by gluing according to another possible embodiment).
• the perforations 411 of the pipe 41 are dimensioned so as to generate gas bubbles with a diameter between 1 and 30 mm, with a pressure drop in the passages of the sleeve 40 between 10 and 200 cm of column d 'waters.
• the gas flow rate through each diffusion orifice is between 2.10 "s NnrVs and 5.10 3 Nm 3 / s.
• this embodiment can be adapted to an injection or distribution system of unclogging gas, modules, fibers or membrane plates arranged both vertically and horizontally, or in any other position relative to the horizontal.
• the devices which will be described below relate particularly to fiber modules or membrane plates arranged vertically (or forming an angle of less than 15 ° with the vertical)
• the unclogging gas is sent to a chamber 10 disposed under the potting 12 of the membranes 13 having in this case an outside diameter between 0.5 mm and 5 mm
• the unclogging gas is distributed between the membranes 13 using a nozzle 51 extending through an opening 15 formed in the potting 12. It is noted that the lower end of this nozzle has a base 512 intended to come to bear under the potting 12, and that this nozzle is designed to be able to be removed from the corresponding opening 15, which causes the withdrawal of the assembly of the nozzle 51 and the anti-backflow cap 50 that it is worn for possible maintenance.
• the nozzle 51 therefore has a cylindrical portion which extends between the membranes over a length of approximately 60 mm above the potting zone 12, and has a diameter of the order of 9 mm (which may vary between 5 and 15 mm depending on other possible embodiments).
• the nozzle 51 has orifices 511 distributed around its periphery.
• the nozzle 51 carries a cap 50 of length approximately equal to that of the nozzle extending above the potting.
• FIG. 5b which shows a magnification of the upper end of a cap 50
• the latter has at least one series of vertical slots 501 regularly distributed around the periphery of the cap.
• the nozzle 51 is flush with the upper surface of the potting 12 (that is to say that it does not exceed the level of the potting, or by only a few millimeters) .
• Ports 511 are provided at the upper end of the nozzle 51.
• the cap 50 having slots 501 as described above extends above the potting over a length of approximately 60 mm (which may vary between 20 and 500 mm depending on other possible embodiments).
• the nozzles 51 may have an upper end in the form of a dome in which are formed orifices 511, this dome being covered by a cap 50.
• FIG. 7b is a top view of a nozzle 50 of the type illustrated in FIG. 7, covered by a cap 50.
• the dome of the nozzle 51 has two orifices 511 between which a slot 501 extends radially. It is noted that this slot 501 extends over a length between the diameter of the base of the dome and one third of this diameter.
• the nozzle 51 has a peripheral shoulder 513 intended to cooperate with a peripheral shoulder formed on a ring 151 placed in each injection opening of the potting.
• the diameter of the nozzle and that of the ring are provided for allow a slight force fitting of the nozzle into the ring. Such a fitting allows the withdrawal of the nozzle from the ring, and the shoulders allow to put the nozzle in abutment to ensure its maintenance in position against the pressure of the unclogging gas.
• valves 8 and 9 each illustrate an embodiment of another approach of the invention, according to which the anti-backflow means are in the form of a valve mounted in the injection openings, the valves being movable between a position according to which they allow the passage of gas and a position for closing the opening, in the event of the injection of cleaning gas being stopped.
• these valves comprise a valve 80 mounted movable in translation inside a ring 81 introduced into an opening of the potting 12. This valve 80 is secured to a nozzle 801, and a return spring 802 is interposed between the end piece 801 and the lower surface of the potting 12.
• the valve moves upwards and creates a passage for gas through the opening in the potting.
• the spring 802 is compressed.
• the valve is returned to the closed position under the action of the return spring 802.
• the stiffness of the return spring 802 is of course chosen so that it allows the opening of the valve for a determined unclogging gas pressure.
• the valves comprise, for each opening formed in the potting, an elastic washer 90. This washer 90 is held on a support 92 extending coaxially with a ring 94 embedded in the opening. The washer 90 is held on the support 92 by a screw 91.
• Another screw 93 allows the adjustment of the support force of the washer on the edges of the opening and / or the adjustment of the stiffness of the washer. It is understood that, under the effect of the injection pressure of the unclogging gas, the periphery of the washer is raised and frees a passage for the gas. When the pressure drops, the elasticity of the washer causes it to come to rest on the edges of the opening and close the passage.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Engineering & Computer Science (AREA)
• Water Supply & Treatment (AREA)
• Separation Using Semi-Permeable Membranes (AREA)

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• 2004
  • 2004-04-29 FR FR0404552A patent/FR2869552B1/fr not_active Expired - Fee Related
• 2005
  • 2005-04-27 AU AU2005247637A patent/AU2005247637A1/en not_active Abandoned
  • 2005-04-27 MX MXPA06012419A patent/MXPA06012419A/es not_active Application Discontinuation
  • 2005-04-27 BR BRPI0510321-5A patent/BRPI0510321A/pt not_active IP Right Cessation
  • 2005-04-27 CA CA002562521A patent/CA2562521A1/en not_active Abandoned
  • 2005-04-27 CN CNA2005800134077A patent/CN1946471A/zh active Pending
  • 2005-04-27 EP EP05763702A patent/EP1742721A1/de not_active Withdrawn
  • 2005-04-27 US US11/568,486 patent/US20080035563A1/en not_active Abandoned
  • 2005-04-27 JP JP2007510077A patent/JP2007534481A/ja active Pending
  • 2005-04-27 WO PCT/FR2005/001051 patent/WO2005115594A1/fr active Application Filing
• 2006
  • 2006-11-15 NO NO20065258A patent/NO20065258L/no not_active Application Discontinuation

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