EP4200256A1 - Système d'ultrafiltration et procédé de lavage à contre-courant - Google Patents

Système d'ultrafiltration et procédé de lavage à contre-courant

Info

Publication number
EP4200256A1
EP4200256A1 EP20841708.9A EP20841708A EP4200256A1 EP 4200256 A1 EP4200256 A1 EP 4200256A1 EP 20841708 A EP20841708 A EP 20841708A EP 4200256 A1 EP4200256 A1 EP 4200256A1
Authority
EP
European Patent Office
Prior art keywords
ultrafiltration
filtrate
line
pressure
raw water
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP20841708.9A
Other languages
German (de)
English (en)
Inventor
Arne Götzel
Marcel HAMMER
Michael KSOLL
Michael Reichelt
Danny RÖSLER
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Wilo SE
Original Assignee
Wilo SE
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Wilo SE filed Critical Wilo SE
Publication of EP4200256A1 publication Critical patent/EP4200256A1/fr
Pending legal-status Critical Current

Links

Classifications

    • 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
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2201/00—Apparatus for treatment of water, waste water or sewage
    • C02F2201/002—Construction details of the apparatus
    • C02F2201/004—Seals, connections
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2201/00—Apparatus for treatment of water, waste water or sewage
    • C02F2201/002—Construction details of the apparatus
    • C02F2201/005—Valves
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2303/00—Specific treatment goals
    • C02F2303/16—Regeneration of sorbents, filters
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2307/00—Location of water treatment or water treatment device
    • C02F2307/14—Treatment of water in water supply networks, e.g. to prevent bacterial growth

Definitions

  • the invention relates to an ultrafiltration system for the production of drinking water in a building with consumers, comprising a number of parallel ultrafiltration modules which can be operated selectively and independently of one another in a filtration mode to supply the consumers with filtrate and in a backwash mode in which the filtrate of at least one first of the ultrafiltration modules is used for backwashing at least a second of the ultrafiltration modules. Furthermore, the invention relates to a backwashing method for such an ultrafiltration system.
  • Ultrafiltration systems for drinking water supply in buildings with filter modules working in parallel are known per se. They are used where a central supply of water of potable quality is not possible or not permanently possible.
  • Residential and multi-family houses, hotels, hospitals, office buildings and public facilities are particularly noteworthy as buildings with such systems, which include a large number of water consumers such as washbasins, toilets, showers, bathtubs, etc. and therefore have extremely dynamic water consumption over the course of the day .
  • a cruise ship is also to be understood as a building in the sense of a mobile hotel.
  • Filter modules of an ultrafiltration system have an inlet connection on the raw water side for supplying raw water and an outlet connection on the filtrate side for supplying filtered water, referred to below as filtrate.
  • filter membranes between the inlet and outlet connections, which filter out microorganisms and dirt particles in the raw water supplied.
  • the filter membrane spatially separates the raw water side from the filtrate side.
  • particles and microorganisms accumulate as filter cakes on the membrane surface, which is known to those skilled in the art as “fouling”. This progressively reduces the filter performance and it becomes necessary to clean the membrane. This can be done by what is known as backwashing, in which the flow through the filter membrane is in the opposite direction to the filter operation, ie from the filtrate side to the raw water side.
  • filtrate is collected in a container and, if necessary, pumped back to the filtrate side for filter cleaning. There it flows through the filter membrane to the raw water side, detaches the particles and microorganisms from the membrane, is removed from the raw water side as so-called retentate and then separated. Appropriate valves are actuated and opened and closed in order to release the pipeline routes required for this or to block certain routes, such as the raw water supply to the filter module to be cleaned or the filtrate supply to the consumers.
  • the disadvantage here is that the filtrate tank and the backflushing pump are required, which take up space, have to be integrated into the system by pipes and lead to corresponding costs. Furthermore, the filter operation of the entire system usually has to be interrupted for backwashing.
  • a challenge when backwashing a first filter module using filtrate from a second filter module is to avoid damaging the membrane from the supply pressure and pressure peaks superimposed on it.
  • the retentate is separated into a free outlet (e.g. according to DIN EN 1717), as a result of which the raw water side is open to the atmosphere during backwashing.
  • the supply pressure can be around 10 bar, for example.
  • the housing of the filter modules can withstand this pressure, such a differential pressure across the membrane, i.e. between the filtrate side and the raw water side, hereinafter referred to as transmembrane pressure or TMP, can destroy the membrane - it bursts.
  • the membrane is designed for a differential pressure of less than 2 bar and can withstand a maximum pressure of approx. 4 bar for a short time.
  • FIG. 1 illustrates this using an exemplary ultrafiltration layer 1 with three parallel ultrafiltration units 3, each consisting of an ultrafiltration module 3a, 3b, 3c, with the ultrafiltration modules 3a, 3b, 3c being identical.
  • the supply pressure is 10 bar above the series connection from the Number of filtering ultrafiltration units 3, here ultrafiltration modules 3b, 3c, and the number of ultrafiltration units 3 to be backwashed, here only ultrafiltration module 3a.
  • the TMP above the two parallel, filtering ultrafiltration modules 3b, 3c is 33.3% of the supply pressure, ie approx. 3.3 bar
  • the TMP above the ultrafiltration module 3a to be backwashed is 66.7% of the supply pressure, ie approx. 6.7 bars.
  • FIG. 1 illustrates the possible use of such disposable filter modules 3a, 3b, 3c, with the baffle plate 9 being arranged in the respective local retentate line 7a, 7b, 7c, i.e. the line between the inlet connection 4a and the central retentate line 7, which leads to free drainage 30 leads.
  • the pressure loss on the ultrafiltration modules increases and on the baffle plate decreases until it becomes ineffective. .
  • baffle plate 9 cannot be set to a desired back pressure. This means that if there is a structural change in the ultrafiltration system 1, the baffle plate 9 will have to be replaced by another suitable baffle plate. Another disadvantage of the baffle plate 9 is that pressure peaks get through unfiltered and damage to the filter membrane 6 can therefore not be ruled out.
  • baffle plate 9 in the local filtrate line 8a, 8b, 8c.
  • the pressure loss generated by the baffle plate 9 also has an effect during filtration operation and thus restricts the delivery of the filtrate to the consumers 40, which experience a correspondingly reduced flow pressure.
  • an ultrafiltration system for producing drinking water in a building with consumers comprising
  • each of which has one or more parallel ultrafiltration modules with a raw water side, a filtrate side and at least one filtration membrane lying between these and which can be operated optionally and independently of one another in a filtration mode to produce filtrate and in a backwash mode to clean the filtration membrane ,
  • a retentate line with which the ultrafiltration units can each be connected to remove retentate from the raw water side for the backwash operation, wherein in the backwash operation filtrate is fed to at least a first of the ultrafiltration units for backwashing to at least a second of the ultrafiltration units, and each ultrafiltration unit via a first line to the filtrate discharge in filtration operation and a second line parallel thereto for the filtrate feed line in backflushing operation is connected to the filtrate line, so that filtrate from the first ultrafiltration unit can be fed to the filtrate side of the second ultrafiltration unit, with a valve for flow prevention in backflushing operation in the first line and a pressure-reducing element in the second line is arranged.
  • the filtrate delivery to the consumer on the one hand and the filtrate delivery to an ultrafiltration unit to be backwashed are fluidically separated or each divided into a separate line.
  • the filtrate is discharged from the filtrate side in filter operation and the filtrate is fed to the filtrate side in backwash operation via different flow paths, so that a pressure reduction on the filtrate side is possible without impairing filter operation.
  • Both lines can be referred to as "filtrate lines" because they convey filtrate, but the second line also forms a backwash line, since it is the only one used to convey filtrate from one ultrafiltration unit for the purpose of backwashing the other ultrafiltration unit from a central filtrate line into which the first Line or all first lines open, the filtrate side of the other ultrafiltration unit to be forwarded.
  • the pressure reducing element in the second line can effectively limit the pressure in the filtrate line for backwashing and thus the TMP during backwashing against the atmosphere above the membrane to be backwashed and the membrane can be protected.
  • the pressure-reducing element can be a baffle plate.
  • the pressure reducing element can be a regulated control valve, for example a motor-operated ball valve.
  • a desired pressure drop can be set across the pressure-reducing element or can be actively regulated, so that if there is a structural change in the ultrafiltration system, the pressure-reducing element does not need to be replaced.
  • a corresponding pressure control can act on the control valve by means of a pressure sensor downstream of the control valve in the direction of flow, the pressure control being set up to control the control valve in such a way that the pressure behind the control valve is kept constant.
  • the pressure-reducing element can be a pressure reducer.
  • a pressure reducer is a pressure valve with an inlet and an outlet side, which always maintains a constant pressure (back pressure) on the outlet side, regardless of the higher pressure (inlet pressure) on the inlet side.
  • a pressure reducer thus causes passive pressure control in a purely mechanical way.
  • a pressure reducer is able to dampen or filter out pressure peaks due to the high reaction speed in contrast to a comparatively sluggish control.
  • the pressure reducer can be adjustable with regard to its back pressure. However, a non-adjustable pressure reducer can also be used.
  • the ultrafiltration units can each be connected to the filtrate line via a separate first line for filtrate discharge in filtration mode and each via a separate second line parallel thereto for filtrate feed line in backflushing mode.
  • two lines in each case open into the central filtrate line, so that in this embodiment variant, with n ultrafiltration units, 2n lines are required for filtrate. Since a pressure-reducing element is arranged in each of the second lines, the number n of pressure-reducing elements corresponds to the number n of ultrafiltration units.
  • the second line is formed from a common section connected to the filtrate line and individual lines branching from it to the individual ultrafiltration units, with the pressure-reducing element being located in the common section. While the respective So a single line is assigned to a specific ultrafiltration unit and is only used to supply backwash filtrate for this ultrafiltration unit, the common section is used by all or for all ultrafiltration units. With n ultrafiltration units, only n+1 lines for filtrate are therefore required, which open into the central filtrate line. This has the advantage that only a single pressure reducing element is required, which acts equally for all ultrafiltration units, depending on which one is to be backwashed.
  • a flow prevention valve can be arranged in series with the pressure reducing element.
  • the or at least some of the valves in the first and/or second line can be switchable (open/closed) or adjustable (0%-100%) control valves. It can thus be defined manually whether and which line should be flown through on the filtrate side. In relation to the case in which a control valve is arranged in each of the first and second lines, this must be done in reverse. Thus, for the filtering operation of an ultrafiltration unit, the valve in the first line must be opened to deliver filtrate and closed in the second line to isolate the filtrate sides of the filtering and backwashing ultrafiltration units.
  • valve in the first line may be closed so that the pressure reducing element is not bypassed or to force the filtrate through the pressure reducing element, and in the second line be open to allow filtrate to be backwashed receive.
  • valves are non-return valves. This is because the behavior of these types of valves is that they allow flow in one direction and prevent flow in the other (reverse) direction.
  • This directionality can be ideally utilized for the present invention, since the first and second line for filtrate is intended to flow through in only one direction.
  • a backflow preventer can be arranged in the respective first line in such a way that its input side is connected to the corresponding ultrafiltration unit and its output side is connected to the filtrate line.
  • a non-return valve can be arranged in the respective second line or in its respective individual line in such a way that its input side is connected to the filtrate line and its output side is connected to the corresponding ultrafiltration unit.
  • backflow preventers in the lines means that controlled valves and corresponding control lines can be dispensed with, so that the costs and effort involved in constructing the ultrafiltration system according to the invention can be saved. Since non-return valves work completely independently, they are also fail-safe in relation to control valves.
  • the ultrafiltration system can thus include a sensor system for determining the differential pressure between the supply line and the filtrate line and an evaluation unit for evaluating the differential pressure.
  • the evaluation unit can then compare the differential pressure with an opening pressure of the non-return valve, eg 0.3 bar, and assume a volume flow greater than zero above the opening pressure and a volume flow equal to zero below the opening pressure. Or can the evaluation unit must be set up to do this.
  • a differential pressure measurement can be used to determine whether the ultrafiltration system is delivering filtrate to the consumers or has possibly not delivered for a certain period of time.
  • the opening pressure is thus well above the measurement tolerance of conventional pressure sensors.
  • the ultrafiltration modules have a large number of hollow-fiber membranes, which separate the raw water side from the filtrate side.
  • the ultrafiltration modules can each have a cylindrical housing in a vertical arrangement as intended.
  • the housing can preferably have a connection to the raw water side in the upper area for the removal of retentate that is produced by the backwashing of the filter membrane on the raw water side. This has the advantage that during backwash operation, air is also removed from the housing on the untreated water side at the same time. Additionally or alternatively, the housing can have a connection to the raw water side in the lower area for the supply of raw water to be filtered. This enables a symmetrical inflow of the ultrafiltration module during filtration. This halves the axial path length to be flowed through in the ultrafiltration module, in particular the length of a hollow fiber with a small inner diameter, and thus the pressure loss during filtration.
  • a housing of the ultrafiltration module has two connections on the raw water side and gives the ultrafiltration module a high degree of flexibility with regard to its use. Furthermore, the housing does not have to be differentiated between top and bottom. Raw water can be fed in or retentate can be removed either via the upper or lower connection or via both connections at the same time.
  • the housing can have a connection located in the upper area when arranged vertically as intended have to the filtrate side for the removal of filtrate that is produced by the filtration on the filtrate side.
  • This has the advantage that during filtration operation air is also removed from the housing on the filtrate side.
  • the housing can have a connection to the filtrate side in the lower area of the housing for the supply of filtrate for backwashing the filter membrane. In the event of service, this allows the modules to be emptied quickly and completely on the filtrate side.
  • a housing of the ultrafiltration module has two connections on the filtrate side and also gives the ultrafiltration module a high degree of flexibility with regard to its use, since it is not necessary to distinguish between top and bottom and the filtrate can be fed in either via the upper, lower or via both connections can be made at the same time.
  • FIG. 1 schematic representation of an ultrafiltration system according to the prior art with baffle plates in the retentate line
  • FIG. 2 a first ultrafiltration system according to the invention in a schematic representation with control valves in the first filtrate line
  • FIG. 3 a second ultrafiltration system according to the invention in a schematic representation with backflow preventers in the first filtrate line;
  • FIG. 4 a third ultrafiltration system according to the invention in a schematic representation with a common backwash line and control valves
  • FIG. 5 a fourth inventive ultrafiltration system in a schematic representation with common backwash line and backflow preventers
  • FIG. 6 a fifth inventive ultrafiltration system in a schematic representation with ultrafiltration modules with two connections each on the raw water and filtrate side
  • FIG. 1 shows an ultrafiltration system 1 using ultrafiltration modules 3a, 3b, 3c according to the prior art.
  • the ultrafiltration system 1 is fed from a source 20 with raw water.
  • This source 20 can be a local water utility or a local Water reservoir such as a tank or cistern.
  • a central supply line 2 connects the ultrafiltration modules 3a, 3b, 3c to the source 20, a pressure booster system 21 being arranged in the supply line 2 in order to provide an inlet pressure PE of approximately 10 bar on the inlet side of the ultrafiltration system 1.
  • PE inlet pressure PE of approximately 10 bar on the inlet side of the ultrafiltration system 1.
  • the latter is necessary above all in tall buildings and/or extensive drinking water distribution networks within the building, since even the supply pressure provided by any supplier alone is not sufficient to ensure sufficient flow pressure, e.g.
  • the pressure boosting system is only symbolized by a pump 21 here.
  • a local supply line goes off to each of the ultrafiltration modules 3a, 3b, 3c, in each of which there is an inlet valve Za, Zb, Zc.
  • the local supply lines each end at an inlet connection 4a, which opens into an untreated water side 5a of the corresponding ultrafiltration module 3a, 3b, 3c.
  • the untreated water side 5a is separated from the filtrate side 5b by at least one membrane 6, from which a discharge connection 4b leads out.
  • the ultrafiltration modules 3a, 3b, 3c are connected via a respective local filtrate line 8a, 8b, 8c, starting from the outflow connection 4b, to a central filtrate line 8, which leads to the consumers 40.
  • Consumers 40 can be washbasin fittings, toilets, showers, tubs, etc., for example.
  • the ultrafiltration modules 3a, 3b, 3c produce filtrate from the raw water, in that the raw water passes through the membrane 6 and particles in the raw water remain adhering to the raw water side 5a or to the membrane.
  • the water or filtrate permeated to the filtrate side 5b is conducted through the local filtrate lines 8a, 8b, 8c to the central filtrate line 8, which then forwards the filtrate to the consumers 40.
  • each ultrafiltration module 3a, 3b, 3c can be operated independently of the other ultrafiltration modules 3a, 3b, 3c in a backwash operation, in which the filter membrane 6 is flown through backwards, ie from the filtrate side 5b to the raw water side 5a.
  • the filtrate used for this comes from at least one of the others Ultrafiltration modules 3a, 3b, 3c.
  • each ultrafiltration module 3a, 3b, 3c is connected via a local retentate line 7a, 7b, 7c, in which there is a retentate valve Ra, Rb, Rc , Connected to a central retentate line 7, which leads to a free outlet 40 at which the retentate is deposited.
  • a baffle plate 9 is arranged in each of these local retentate lines 7a, 7b, 7c, at which an additional pressure loss occurs during backwash operation, by which the pressure across the corresponding backwashed membrane 6 is relieved.
  • the baffle plates 9 are connected in series with the respective filter module 3a, 3b, 3c during backwashing in the direction of flow.
  • the determination of which ultrafiltration module 3a, 3b, 3c should filter at a time and which should be cleaned by backwashing is done by setting the inlet valves Za, Zb, Zc and the retentate valves Ra, Rb, Rc, these valves being related to each ultrafiltration module 3a, 3b, 3c can be driven in inverted fashion.
  • two first ultrafiltration modules 3b, 3c deliver filtrate, while a second ultrafiltration module 3a (right) is currently being backwashed, with the filtrate being used for consumers 40 on the one hand and for backwashing the second ultrafiltration module 3a on the other hand .
  • the first two ultrafiltration modules 3b, 3c are therefore in filtration mode, while the second ultrafiltration module 3a is in backwash mode.
  • the arrows on the various lines and within the ultrafiltration modules 3a, 3b, 3c indicate the respective direction of flow.
  • the valve positions are therefore as follows: As can be seen in Figure 1 and as will be used below as a convention, filled valve symbols indicate closed valves and unfilled valve symbols open valves.
  • the advantage of such an ultrafiltration system 1 is that the individual ultrafiltration modules can be backwashed during operation of the ultrafiltration system, i.e. while filtrate is being delivered to the consumers 20, so that they experience no or at least no significant impairment. There is therefore no standstill or interruption of the filtrate delivery to the consumers 20. Furthermore, the ultrafiltration system 1 according to the invention does not need a backwash tank and a backwash pump, which reduces the effort and costs for its production.
  • FIG. 2 shows a first embodiment variant of an ultrafiltration system 1 according to the invention in a schematic representation analogous to system 1 in FIG. 1. The differences are therefore primarily addressed below. Otherwise, reference is made to the explanations for FIG.
  • the ultrafiltration system 1 consists here, for example, of three parallel ultrafiltration units 3, with only two or more than three such units 3 being able to be present according to another embodiment variant.
  • the ultrafiltration units 3 each have one or more parallel ultrafiltration modules 3a, 3b, 3c, as have been described with reference to FIG.
  • FIG. 2 only shows one ultrafiltration module 3a, 3b, 3c per ultrafiltration unit 3, two or more, preferably three, parallel ultrafiltration modules 3a, 3b, 3c can each form an ultrafiltration unit 3.
  • all ultrafiltration units 3 have the same number of ultrafiltration modules 3a, 3b, 3c.
  • the ultrafiltration modules of the same ultrafiltration unit 3 can be structurally combined in a common mount, also called a rack.
  • the ultrafiltration system 1 can have two, three or more ultrafiltration units 3 or racks in one embodiment variant, which are hydraulically connected in parallel to one another. It makes sense for all ultrafiltration modules 3a, 3b, 3c to be structurally identical. If each ultrafiltration unit 3 includes only one ultrafiltration module 3a, 3b, 3c, as shown in FIG. For this reason, the reference numerals 3a, 3b, 3c of the ultrafiltration modules are used in the following in an analogous manner to differentiate between the three ultrafiltration units 3.
  • the ultrafiltration units 3a, 3b, 3c can be operated optionally and independently of one another in a filtration mode to produce filtrate and in a backwash mode in order to be able to clean the filtration membrane 6 of each ultrafiltration module or membranes 6 of the ultrafiltration modules of each ultrafiltration unit 3a, 3b, 3c, with in backwash operation, filtrate is supplied to at least a first of the ultrafiltration units 3a, 3b, 3c for backwashing to at least a second of the ultrafiltration units 3a, 3b, 3c.
  • there are two first ultrafiltration units in filtration mode which are assigned the reference numbers 3b and 3c here, while a second ultrafiltration unit with the reference number 3a is in backflushing mode.
  • the valve positions of the inlet valves Za, Zb, Zc and the retentate valves Ra, Rb, Rc are therefore as stated in the previous table.
  • each ultrafiltration unit 3a, 3b, 3c has a first line 8a, 8b, 8c for filtrate discharge in filtration operation and a parallel second line 8a', 8b', 8c 'is connected to the filtrate supply line in backwash operation with the central filtrate line 8.
  • filtrate from the first two ultrafiltration units 3b, 3c can be fed via the corresponding second line 8a' to the filtrate side of the second ultrafiltration unit 3a, so that there are different flow paths for the filtrate supply and for backwashing, and the second line 8a' serving as a backwash line is provided with a protective device can be done without impairing the filtrate supply.
  • the untreated water side 5a of the second ultrafiltration unit 3a is connected to the free outlet 30 tied together. Since the atmospheric pressure acts on the raw water side 5a, the inlet pressure PE is in the absence of a suitable protective device above the series connection of the two parallel first ultrafiltration units 3b, 3c and the second ultrafiltration unit 3a, so that assuming identical hydraulic resistances of the ultrafiltration units 3a, 3b, 3c (Identical units) 1/3 of the input pressure PE is applied over the two parallel first ultrafiltration units 3b, 3c and 2/3 over the second ultrafiltration unit 3a.
  • the second ultrafiltration unit 3a With an inlet pressure of 10 bar, the second ultrafiltration unit 3a would be loaded with about 6.7 bar.
  • a pressure-reducing element 10 is arranged in the second line 8a'. Strictly speaking, this is the case in the second line 8a', 8b', 8c' of each ultrafiltration unit 3a, 3b, 3c, since the remaining ultrafiltration units 3b, 3c are also flushed at some point.
  • the pressure reducing element 10 forms an additional hydraulic resistance and thus generates a pressure drop, so that the corresponding filter membrane 6 is subjected to less pressure.
  • the pressure-reducing element 10 is suitably selected or set in such a way that on its outlet side directed towards the corresponding ultrafiltration unit 3a there is a pressure which is equal to or lower than a desired maximum pressure load on the filter membrane 6 .
  • this pressure on the outlet side is about 2 bar.
  • a corresponding valve Fa is to be provided in this line, which must be closed for the backwash operation.
  • This valve Fa is referred to below as the filtrate valve.
  • Such a filtrate valve Fa, Fb, Fc must be present in each of the first lines 8a, 8b, 8c, since the other ultrafiltration units 3b, 3c will also be flushed at some point.
  • the corresponding filtrate valve In the first lines 8a, 8b assigned to the two first ultrafiltration units 3b, 3c, however, the corresponding filtrate valve must be open during the backwashing of the second ultrafiltration unit 3a, so that this filtrate can be fed into the central filtration line 8 or for flushing the second ultrafiltration unit 3a.
  • the respective filtrate valve Fa, Fb, Fc thus serves to direct the filtrate through the pressure-reducing element 10 during backwashing and to bypass the pressure-reducing element 10 during filtration. Consequently, the following valve states are present for the operating case in FIG.
  • the pressure-reducing element 10 can be a baffle plate, for example, as in FIG. 1, or a pressure-dependent control valve.
  • a regulated control valve the pressure is measured on its outlet side and the degree of opening of the valve is adjusted depending on the measured pressure so that it corresponds to a desired value, e.g. between 2 bar and 4 bar.
  • This adjustment is made as part of a regulation of a control and regulation unit, not shown in FIG.
  • this can be the control unit that also switches or adjusts the other valves Za, Zb, Zc, Ra, Rb, Rc, Fa, Fb and Fc.
  • the pressure reducing element 10 is preferably a pressure reducer.
  • a pressure measurement and control can thus be dispensed with.
  • the pressure reducer On the outlet side, the pressure reducer always sets the pressure for which it is designed and immediately filters out pressure peaks that would get through in the event of pressure regulation due to their inertia.
  • a pressure reducer between the filtrate line 8 and the ultrafiltration unit 3a to be backwashed during the backwashing, a safe and fast, direct (mechanical) pressure regulation is realized independently of the flow.
  • the inlet valves Za, Zb, Zc, retentate valves Ra, Rb, Rc and/or filtrate valves Fa, Fb, Fc can be controlled, in particular switchable (open/closed) or adjustable (0...100%) control valves that be actuated, for example, electrically, electromagnetically or pneumatically.
  • the control valves are controllable engine valves.
  • FIG. 3 shows an alternative embodiment of an ultrafiltration system 1 according to the invention, which differs from that in FIG. 2 only in that the filtrate valves Fa, Fb, Fc are formed by non-return valves. This has the advantage that no active activation of the filtrate valves Fa, Fb, Fc is required.
  • This embodiment variant makes use of the fact that the first line 8a, 8b, 8c and second line 8a', 8b', 8c' are flown through in only one direction, depending on the operating case "filtering” or “backwashing” alternatively. Because the non-return valves Fa, Fb, Fc allow flow in only one direction due to their directional nature, they are particularly suitable for the ultrafiltration system 1 according to the invention. They are arranged in the first line 8a, 8b, 8c in such a way that their input side is connected to the corresponding ultrafiltration unit 3a, 3b, 3c and their output side is connected to the central filtration line 8.
  • the non-return valve Fa, Fb, Fc opens independently of the volume flow. This opening pressure is e.g. approx. 0.3 bar even for the smallest volume flows. If the retentate valve Ra of the second ultrafiltration unit 3a is open, the pressure conditions are such that the pressure at the filtrate valve Fa of this second ultrafiltration unit 3a is applied from its outlet to the inlet side. Consequently, this filtrate valve Fa blocks, so that during backwashing no filtrate from the filtrate line 8 (with a system pressure of max.
  • FIG. 4 shows a further embodiment of an ultrafiltration system 1 according to the invention. It differs from that in FIG. 2 in that all second lines 8a', 8b', 8c', before they open into the central filtrate line 8, unite to form a common section 8', which then opens into the central filtrate line 8. Looked at in another way, the second line is formed from this common section 8', which is connected to the filtrate line 8, and individual lines 8a', 8b', 8c' branching off from it to the individual ultrafiltration units 3a, 3b, 3c.
  • This embodiment variant makes it possible to save on pressure reducing elements 10, since only a single pressure reducing element 10 is required, which is located in the common section 8' and is therefore used equally by all ultrafiltration units 8a, 8b, 8c in the respective backwash operation.
  • the flushing valves Sa, Sb, Sc can be designed identically to the inlet valves Za, Zb, Zc, retentate valves Ra, Rb, Rc and/or filtrate valves Fa, Fb, Fc.
  • FIG. 5 shows a further embodiment of an ultrafiltration system 1 according to the invention, which differs from the embodiment in FIG. 4 in that the filtrate valves Fa, Fb, Fc and the flushing valves Sa, Sb, Sc are formed by non-return valves. What was said about FIG. 3 also applies to this variant.
  • the backflow preventers Sa, Sb, Sc in the individual lines 8a', 8b', 8c' are arranged in such a way that their respective input side is connected to the common section 8' and their respective output side is connected to the corresponding ultrafiltration unit 3a, 3b, 3c.
  • the pressure present at the non-return valve Sa is oriented from the input to the output side, i.e. higher on the input side, and is above the opening pressure, so that the non-return valve opens.
  • the pressure on the outlet side (corresponds to the pressure in the filtrate line 8) is higher than on the inlet side (pressure reduced by pressure-reducing elements 10), so that these non-return valves Sb, Sc are closed. Controlled flushing valves can thus be dispensed with.
  • FIG. 6 shows a further embodiment of an ultrafiltration system 1 according to the invention.
  • the thickness of the lines symbolizes the pressure on the corresponding water-carrying pipe, with the pressure being greater the thicker the line is.
  • the dashed lines carry no water in the operating case shown, because the corresponding valve is closed.
  • the ultrafiltration units 3 are formed by ultrafiltration modules 3a, 3b, 3c with an elongated, essentially cylindrical housing. They each have a large number of hollow fiber membranes 6 between the raw water side 5a and the filtrate side 5b, with the interior of the hollow fiber membranes belonging to the raw water side 5a and the space outside the hollow fiber membranes 6 to the filtrate side 5b in this embodiment variant.
  • Each of the two sides 5a, 5b has two terminals which are respectively arranged at opposite axial ends of the housing.
  • each ultrafiltration module 3a, 3b, 3c therefore has a lower inlet connection 4au and an upper inlet connection 4ao each for the raw water side 5a, and a lower inlet connection 4bu and an upper outlet connection 4bo each for the filtrate side 5b.
  • Raw water is fed in via the supply line 2 in filtration operation spatially from below via both inlet connections 4au, 4ao, which are connected to one another outside the ultrafiltration modules 3a, 3b, 3c via an intermediate line.
  • the central supply line 2 runs below the ultrafiltration units 3a, 3b, 3c.
  • the retentate is discharged spatially upwards from the intermediate line into the central retentate line 7, which runs above the ultrafiltration units 3a, 3b, 3c. This has the advantage that reliable venting is effected during backwashing.
  • the inlet valves Za, Zb, Zc are each between the central supply line 2 and the corresponding intermediate line.
  • the retentate valves Ra, Rb, Rc are each between the central retentate line 7 and the corresponding intermediate line.
  • the filtrate is discharged during filtration operation via the upper discharge connection 4bo into the central filtrate line 8, which runs spatially above the ultrafiltration units 3a, 3b, 3c.
  • the respective first line 8a, 8b, 8c connects the upper outflow connection 4bo of the corresponding ultrafiltration unit 3a, 3b, 3c to the central filtrate line 8, which leads to the consumers 30.
  • a filtrate valve Fa, Fb, Fc in the form of a backflow preventer according to Figures 3 and 5.
  • a second line 8', 8a', 8b', 8c' connects the central filtrate line 8 with each of the ultrafiltration units 3a, 3b, 3c.
  • the second line 8', 8a', 8b', 8c' consists of a common section 8' and individual lines 8a', 8b', 8c'.
  • a pressure reducer 10 is arranged in the common section 8'.
  • the common section 8' connects the central filtrate line 8 with the individual lines 8a', 8b', 8c', which each lead to one of the lower inlet connections 4bu of the ultrafiltration units 3a, 3b, 3c and each have a flushing valve Sa, Sb, Sc in shape a backflow preventer according to Figure 5 included.
  • the common section 8 thus forms a collecting line for the pressure-limited filtrate connections 4bu.
  • FIG. 6 also shows an inlet pressure sensor 11 for measuring the inlet pressure PE in the supply line 2 and an outlet pressure sensor 12 for measuring the outlet pressure PA in the central filtrate line 8 .
  • the measurement signals from these pressure sensors 11, 12 are fed to an evaluation unit 13, which is set up in particular to determine during filtration operation of the ultrafiltration system 1 whether the differential pressure between the inlet pressure PE and the outlet pressure PA exceeds the opening pressure of the backflow preventers Fa, Fb, Fc. If this is the case, it can be concluded that at least one of the backflow preventers Fa, Fb, Fc is open and therefore a volume flow exists, i.e. the ultrafiltration system 1 supplies drinking water to the consumers 40 without the need for an additional volume flow sensor or volume meter.
  • the invention includes any changes, alterations or modifications of exemplary embodiments that require the substitution, addition, alteration or omission of elements, Components, process steps, values or information as a subject matter, as long as the basic idea of the invention is retained, regardless of whether the change, alteration or modifications lead to an improvement or deterioration in an embodiment.

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

Abstract

L'invention concerne un système d'ultrafiltration (1) pour la production d'eau potable, avec des unités d'ultrafiltration parallèles (3), qui présentent chacune un ou plusieurs modules d'ultrafiltration parallèles (3a, 3b, 3c) avec un côté eau brute (5a), un côté filtrat (5b) et au moins une membrane de filtration (6) située entre eux, et qui peuvent être exploités en mode filtration et en mode lavage à contre-courant. Chaque unité d'ultrafiltration (3) est raccordée à une conduite centrale de filtrat (5b) au moyen d'une première conduite (8a, 8b, 8c) pour l'évacuation du filtrat en mode filtration et au moyen d'une seconde conduite (8', 8a', 8b', 8c'), parallèle à la première conduite, pour l'alimentation en filtrat dans le mode de lavage à contre-courant, de sorte que le filtrat de la première unité d'ultrafiltration (3) peut être transporté vers le côté filtrat (5b) de la seconde unité d'ultrafiltration (3). Une soupape (Fa, Fb, Fc) est disposée dans la première conduite (8a, 8b, 8c), pour empêcher le reflux en mode de lavage à contre-courant. Un élément réducteur de pression (10) est disposé dans la seconde conduite (8', 8a', 8b', 8c') pour protéger les modules d'ultrafiltration (3a, 3b, 3c) contre des pressions trop élevées en mode lavage à contre-courant. L'invention concerne également un procédé de lavage à contre-courant pour ledit système d'ultrafiltration (1).
EP20841708.9A 2020-12-21 2020-12-21 Système d'ultrafiltration et procédé de lavage à contre-courant Pending EP4200256A1 (fr)

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Publication number Priority date Publication date Assignee Title
DE10164555A1 (de) * 2001-12-14 2003-06-26 Seitzschenk Filtersystems Gmbh Cross-Flow-Mikrofiltrationsanlage und Verfahren zum Betreiben einer Cross-Flow-Mikrofiltrationsanlage
DE102006012198A1 (de) 2006-03-16 2007-09-27 Seccua Gmbh Steuerungen eines Filtrationssystems
DE102008039676A1 (de) 2008-08-26 2010-03-04 Inge Watertechnologies Ag Einrichtung und Verfahren zum Rückspülen von Filtermembranmodulen
WO2013002244A1 (fr) * 2011-06-29 2013-01-03 東レ株式会社 Procédé de filtration sur membrane et dispositif de filtration sur membrane
US20160304372A1 (en) * 2015-04-17 2016-10-20 General Electric Company Subsurface water treatment system
DE102017208730A1 (de) 2017-05-23 2018-11-29 Krones Ag Verfahren für den Crossflow bei der Membranfiltration von Bier
DE102017117419A1 (de) 2017-08-01 2019-02-07 Sartorius Stedim Biotech Gmbh Filtrationsvorrichtung mit integriertem Flussminderer und Verfahren zur vollständigen Benetzung einer Filtermembran

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