FR2855821A1 - Water demineralisation unit providing regeneration of ion exchange resins has stack of modules with alternating cationic and anionic resins - Google Patents

Abstract

The water demineralisation unit consists of a container (12) with a removable cover, filled with ion exchange resins in separate rigid modules (1, 2, 3, 4, 5, 6), each containing either a cationic or anionic resin and alternating with one another. The modules are in a stack with a cationic resin module at the bottom, an anionic resin module above it, and so on to the top, with a total of at least six modules - three of each. The modules are in cylindrical or other shape, depending on the shape of their container, and are joined together by matching threaded projections and recesses with seals. Each module has at least one hole for filling or extracting ion exchange resins. The module container is in two halves (13, 14) with adjoining flared ends fitted together with a seal (22) between them and fastened by a collar (24) in two semi-cylindrical halves (24a, 24b). In addition, filters can be positioned between the modules to give demineralised water of greater puri ty, sterility or for specific applications.

Description

The present invention relates to a demineralization device

  water and regeneration of ion exchange resins, comprising a container equipped with a removable cover and which contains a multiplicity of ion exchange resins.

  Ion exchange resin devices composed of anions and cations are usually used, housed in mixed beds in containers of variable volumes, for example 10, 20 or 25 liters. These systems make it possible to demineralize water in the form of a drain. The water circulates in the containers through the resins, either from bottom to top, or from top to bottom.

  A classic distribution of mixed beds, frequently used for the production of pure or demineralized water, is 60% anionic resins and 40% cationic resins. These resins can be housed in bags which are stacked one on top of the other inside a vertical cylindrical container, pierced at its upper and lower ends with orifices connected to water pipes to be treated, and provided with a cover at its upper end.

  Thus, FR-A-2 636 940 (88 12678) describes a device with deformable porous bags containing the resins, stacked in an enclosure provided with means for compressing the bags after their placement. Therefore the used resins can be removed and replaced with fresh resins by changing only the bags, without having to dismantle and reassemble the enclosure as in other known devices. The bags are arranged in a variable manner depending on the type of demineralization sought; for example, a series of 5 bags each filled with a mixture of strong cation and strong anion resins provides complete demineralization with high resistivity.

  Systems are also known comprising a column containing all the anions and a column containing all the cations. Each column 30 is connected to the others in series by a network of pipes, so that the raw raw water passes through all the columns to allow the desired water to be produced.

  In all cases, when the resins are saturated, they must be reprocessed with sodium hydroxide and acids to regenerate them. For this purpose the materials are separated by injecting pressurized water into a column from the bottom, which results in the cations remaining at the bottom while the anions move upwards.

  These known techniques have various drawbacks. The 5 results obtained are random, the resins not being treated in a very satisfactory manner. It is observed in the storage bags (approximately 50 kg) that the regenerated resins dry out on the top of the bag, while an accumulation of acid or soda residues is observed at the bottom of the bags, which reduces the quality filtration. In addition, expensive special reprocessing machines are required.

  Resins in mixed beds grouped in the same container simplify the use, but offer a low filtration autonomy, this then often having to be compensated by a greater use of materials.

  In general, the operation of these systems is relatively expensive for users (low autonomy and cost of reprocessing) and somewhat complex for specific demineralization, because of the numerous containers which must then be used. For distributors, the low autonomy increases the comings and goings between the user and the material reprocessing center. Reprocessing begins by emptying the container and materials, then placing these same materials in the separation column. This separation of anions and cations is never 100% successful, while still remaining acceptable, leaving a percentage of resins destroyed in contact with acid or sodium hydroxide. During these different phases of material transfer, by repeated operations, the loss on the ground of these over the months becomes significant. In addition, all these manipulations are tedious and require significant physical expenditure.

  The object of the invention is to propose a device of the type defined above, in which these various drawbacks are to a very large extent eliminated, and whose performance is greatly increased compared to that of known systems.

  According to the invention, the device for demineralizing water and regenerating ion-exchange resins comprises rigid modules, each of which contains only a cationic resin or an anionic resin, and these modules are arranged so as to alternate a module. of cationic resin and an anionic resin module.

  The tests carried out have made it possible to establish that this separation between the anions and the cations in the different modules, supplemented by an alternation in their stacking, results in performances much superior to those of known devices. Thus by way of nonlimiting digital example 10, a volume of 3.5 liters of resins placed in accordance with the invention in the container, makes it possible to demineralize suitably from 344 to 460 liters (instead of 173 liters with 3.5 liters of resins in mixed bed) of hard water whose TH exceeds 35, and this with a continuous flow of 480 liters / hour or 8 liters / minute.

  With 7 liters of resins arranged according to the invention and starting from the same water, demineralized 1030 liters of water instead of 505 liters in a mixed bed.

  The resins used during the tests are M 600 and S 100 from BAYER.

  Preferably according to another characteristic of the invention, a cationic resin module is placed first at the bottom of the stack of resin modules, then above an anionic resin module, and so on continuing the alternating to the top of the container.

  In general, thanks to the invention, the ion exchange increases from 2 to 4 times compared with the known prior devices with equal volume of resins. This considerable increase in performance opens up many new possibilities (juxtaposition of different resins, etc.), generates a reduced cost price and a reprocessing that is easier to implement, without sophisticated equipment.

  According to an advantageous embodiment, the resin modules are at least six in number, on the basis of three cationic resin modules (C +) and three anionic resin modules (A-).

  Preferably according to a characteristic of the invention, the cationic resins and the anionic resins respectively form substantially 50% by volume of all the resins.

  A particularly interesting combination is, starting from the bottom 5 of the container: C + (strong) A- (weak) C + (strong) A- (strong) C + (strong) A- (weak) distributed with the same amount of anions and cations. This combination saves the amount of anions (which are more expensive than cations), while increasing the exchange; the preferred average mixture by volume is 60/40, 60 being the percentage of anion for a mixed resin bed.

  Preferably the modules are cylindrical and provided at their upper part with a threaded cylindrical section, allowing their fixing by screwing in a corresponding threaded part arranged on the lower module.

  According to another embodiment of the invention, the container consists of two superimposed half-containers, identical and provided with removable securing means, each half-container containing the same number of rigid modules each containing an exchange resin ions.

  This embodiment divides the height of the column by a central opening, which has the advantage of giving it easy access to the modules by reducing handling. In addition, while in the construction with a single container the height thereof is limited to approximately 0.80 m so that the operator can, by bending over, gain easy access to the lowest module, the second construction has two and a half25 containers practically double the height of the container, using two half-containers of about 0.75 m each.

  Other features and advantages of the invention will become apparent during the following description of a non-limiting embodiment of the invention, given with reference to the appended drawings in which: Figure 1 is an elevation view , on a reduced scale, of an embodiment of the device for demineralizing water and regenerating ion exchange resins according to the invention, the external enclosure of the container not being shown for the purpose of simplifying the drawing .

  Figure 2 is a top view of a support grid for a rigid resin module, integrated into the base and at the top of each module of the device of Figure 1.

  Figure 3 is an overall elevational view of the container and the modules of Figures I housed therein.

  The device of FIGS. 1 to 3, intended for demineralization of water and for the regeneration of ion exchange resins, illustrates an embodiment of the invention.

  It comprises a container 12, preferably cylindrical and equipped with a removable cover at its upper end. The latter as well as the bottom of the container are each pierced with a hole allowing water circulation under pressure from bottom to top (arrows E and S in Figure 3), or from top to bottom.

  The container 12 contains a set of similar rigid modules 15 superimposed, six in number 1, 2, 3, 4, 5 and 6, from bottom to top, which each contain an ion exchange resin. The modules 1-6 are cylindrical if the container 12 is cylindrical, or have any other shape depending on the geometry of the container to which they correspond.

  Preferably, the container 12 contains at least six modules 1-6, the results obtained being greater than those obtained with a number of modules less than six.

  At their lower part, the modules 1 ... are provided with a threaded cylindrical section 7 allowing their removable fixing by screwing in a corresponding tapped part 7a, arranged on the upper end of the respective lower module. Each module 1 ... 6 has at its base, just above the threaded section 7, a first grid 27a for supporting the corresponding resin, provided with a peripheral ring 27c for bearing on an interior shoulder of the module (1 ..) coaxial to section 7.

  Each module 1-6 is also provided, at its upper part, with a second grid 27b for holding the resins, on which the grid 27a can be integrated when the modules 1-6 are fitted one on the other. other.

  In addition, under each grid 27b, a filter, not shown, can be inserted.

  Each module is additionally pierced with pressure distribution openings 8.

  Seals 9 concentric with the threaded parts 7a are interposed between the modules 1- 6, the outside diameter of these seals 9 being substantially equal to the outside diameter of the cylindrical modules 16.

  An opening 31 is provided in each module 1 ... 6 to allow filling or emptying of the resins, and each module can be provided with a numbering label 26 ..

  The device is completed by a handling handle, not shown, which can be adapted to each module and makes it possible to introduce or extract them one by one from the container. The latter has a height limited in practice to about 0.80 m, so that the operator can easily install and extract the lowest module 1.

  Preferably, a cationic resin module is placed first at the bottom of the stack in the first lower module 1, then above an anionic resin module 2, and so on, continuing the alternation up to the top of the container. In the case where this contains six modules, three modules of cationic resin and three modules of anionic resin are thus provided.

  The modules 1-6 communicate with each other through the interior of the sections 7 which can be screwed into the threaded parts 7a surrounding the grids 27b. These passages allow the circulation of water from one end to the other of the container inserted in the corresponding network of pipes, not shown. However, the modules may as well be assembled together in a different way, for example by simple interlocking.

  Preferably, the cationic resins and the anionic resins respectively form substantially 50% by volume of all 25 resins, which has the advantage of saving the quantity of anions, more expensive than the cations, while increasing the 'exchange. The average mixture is 60/40, 60 being the percentage of anions.

  The container 12 consists of two half-containers 13, 14 superimposed, for example cylindrical, identical and provided with removable means 30 for securing. A tapped central opening 10 is arranged at the base of the lower half-container 13 and a similar central opening 20 is formed in the top of the upper half-container 14, pipes not shown being able to be connected to these holes 10, 20.

  Each half-container 13, 14 contains the same number of rigid cylindrical modules - namely three marked 1 to 3 and 4 to 6 respectively containing ion exchange resins.

  In the example described, the means for connecting and securing the two half-containers 13, 14 comprise two annular flanges 19, 21 arranged respectively at the base of the upper half-container 13 and at the upper end of the half-container lower 14. These flanges 19, 21 are each profiled in V with a radial branch 19a, 21a (horizontal when the container 12 is vertical) and a branch 19b, 21b, the latter 10 being inclined so as to be oriented respectively upwards. for the branch 19b and downwards for the branch 21b, by defining together a frustoconical surface projecting transversely to the container 12. A seal 22 is formed between the two flanges 19, 21 and this seal is fitted with lugs 23 of holding on the radial branch 21a of the lower rim 15 21.

  A closure collar 24 consists of two semi-cylindrical half-straps 24a, 24b profiled so as to each comprise two lips 25, 25a in a U shape. At one of their ends, the half-straps 24a, 24b are fixed on a lug 26 of support secured to the upper end of the lower half-container 14, for example by welding.

  Thanks to this arrangement, the two half-hoops 24a, 24b can be applied, with clamping, on a respective half-circumference of the frustoconical bearing surface (19b, 21b) of the two flanges 19, 21, ensuring a removable locking of the two half-containers 13, 14 one on the other. Locking is achieved with a threaded rod 30 fitted with a butterfly nut 31 for tightening. To execute the locking, it suffices to fold the two half-hoops 24a, 24b around the container 13, 14: the rod 30 comes to fit between the lips 25, 25a and finally the butterfly 31 is screwed, which allows crush the gasket 23 while sealing it.

  Furthermore, in the lower and upper ends of the two half-containers 13, 14 are inserted two respective cylindrical seals 28, 29 which maintain and seal the modules 1- 6.

  Depolluting filters, not shown, can be interposed between the modules, for particular applications such as obtaining demineralized water of greater sterility.

  The division of the container 12 (cylindrical or of any other geometry) 5 into two identical half-containers 13, 14 makes it possible to provide a central opening and to give easy access to the modules 1-6 (in number which can obviously be six or more ) while reducing handling.

  Furthermore, its total height can, thanks to this divided arrangement, reach about 1.75 m without giving rise to handling difficulties, so that the capacity of the container can be greatly increased compared to that of the container of Figures 1 to 3.

  The two identical parts of the container 12 reduce the manufacturing costs. At the upper end and at the lower end thereof, threads are inserted for distribution fittings on the central part.

  The container can be made of various materials (stainless steel, food-grade polyethylene), and various feet, handles and fittings can be provided.

  For the putting into service of the containers or their reprocessing, the handling remains the same.

  As the containers do not return to the reprocessing center, it is also possible, according to an alternative embodiment of the invention, to produce a wall support integrated with the container 12, and to fix the upper half-portion 13 on a sliding rail fitted with an opening lock 25 (not shown). This sliding of the value of a half height of the container upwards allows access to the modules 15 ..., which can thus be disassembled easily without effort, because the work is carried out at a height not creating fatigue , without having to lay the upper half-part 13 on the ground, which facilitates the handling of the 30 modules.

  Containers and modules can be manufactured in different sizes as required, depending on the volumes of water to be treated. In addition, the two half-containers 13, 14 can be replaced by a single container in one piece.

  In its various possible embodiments, the invention has, in addition to the advantages already mentioned, the following advantages.

  The alternation of cationic and anionic resins in the container, with at least six alternating modules, considerably improves the exchange function of the resins, therefore the volume of water which can be treated from the same volume of resins. It makes it possible to use fewer anions (whose cost per liter is high), while increasing the autonomy of filtration.

  Greater ease of juxtaposition of the different resins is possible (cations: strong, weak; anions: strong, weak, other resins, activated carbon, hydrophilic, hydrophobic filters, etc.) depending on the quality of filtration sought. The insertion of complex strainers is no longer necessary.

  The economy of scale is considerable, both in use and in reprocessing and manufacturing, which is simplified.

  The implementation and mixing of different resins, as well as withdrawal into the same container, is greatly facilitated, and easily allows different filtrations.

  The invention makes it possible to produce pure demineralized water or to carry out other filtrations in numerous fields, at a much lower cost than hitherto.

  Other advantages also emerge from the above description: * Simplicity of use and reprocessing; * Greater use of the exchange, therefore greater filtration autonomy; * Multitude of workable combinations; * The system easily adapts to different filtration; Improved ion exchange thanks to the independence of each material, even with very hard water; * Plurality of cylindrical modules in the same container; * Each module materializes a chamber in the container, hence multiple feasible combinations between resins in the same container, without risk of mixing.

  These similar cylindrical modules (1-6) are equipped with a resin retaining grid, which channels the passage of the liquid flow from one module to the other from bottom to top. These similar modules partition the resins, which makes it easier to hold them up and thus work against the current. The partitioning of the modules distributes the empty spaces necessary for the expansion of the resins in these modules, and divides them into mini spaces according to the number of modules. This allows the container to be fed against the current, improving performance by about 70% without the need for sophisticated strainers or ramps, and simplifies the manufacture of the container.

  The weight of the resins distributed in the series of modules housed in the container reduces their compaction on the grids 7 of the modules.

  In addition, the diameter of each grid 7 corresponds to the diameter of the container, thus respecting the principle of the drain over the entire height of the column formed by the container.

  To obtain very pure water, hydrophilic and hydrophobic discs or filters can be inserted between each module (for very specific applications) representing in a container several bacteriological barriers (or other pollutants).

  The resins trapped in the modules can be easily identified by creating modules of different colors. Each color corresponding to a resin quality, a code can be created.

  Thanks to this code, it is easy to create different combinations for demineralization. These lightweight modules simplify transport. Each module can have a color corresponding to a type of resin. By reporting these definitions (color / resin) on a table, users, according to their demineralized water needs, can have access to multiple combinations.

  The operation of the container against the current, by circulation of water 30 from bottom to top - through the orifices 10, 20 in the case of the container 12, eliminates the pressure drops without the need to resort to sophisticated strainers or ramps.

  The same container is used for reprocessing, which allows better regeneration of the resins. To do this, simply group the modules of the same color, assemble them, and put them back upside down in the container. Thus the reprocessing standards are respected, and we can again work against the current for better reprocessing.

  The modules, made for example of rotomolded polyethylene, are easy to handle, inexpensive to manufacture, light. There is no return of the container with the modules for reprocessing, which reduces transport costs. The modules are easy to film, which allows them to keep their humidity and protects them from bacteria. This seal makes it possible to send small quantities in a carton (for example by post) or to store them. It is the same for the users, which constitutes a guarantee of quality which allows them to store the modules filled with resins, and when opening, to have a quality of resins in perfect condition of use.

  Each module retains its resin throughout its life, which facilitates the monitoring of the resin and allows rapid identification in each module (module colors). It is easy to number them or assign them a bar code, in order to perform computer traceability, and thus to know the age of each module, the number of reprocessings. 20 The user can in this way know that the reprocessed module is indeed the one he has purchased previously, know the number of reprocessing performed on it, and the remaining potential of the resins at the exchange level (the average duration life of a resin depending on its use is 4 to 6 years), hence safety in use and total transparency.

  The risk of spilling materials between use and reprocessing is eliminated, as is that of finding anions mixed with cations after separation of the materials, in the separation column. Indeed often in the prior art, for the sake of economy, the old and new resins are grouped in the column, hence a difficulty in evaluating the age of the resins and recalculating their lifespan according to the number restatements.

  The first phase of reprocessing, bulky and constraining, (column of separation of materials, valves, handling etc.) is no longer necessary, hence saving time, money and water.

  The invention is susceptible of numerous other alternative embodiments. Thus for example the rigid modules as well as the container can have any shape other than cylindrical, and their number can vary widely, however being at least four and preferably six, the latter number having given rise to the highest performance. . Similarly, the removable locking means of the two half-containers 13, 14 can obviously be different from those shown in FIG. 3. The depolluting filters that can be interposed between the modules make it possible to obtain demineralized water of greater purity, more sterile or for certain very specific applications.

Claims (11)

  1. Device for demineralizing water and regenerating ion exchange resins, comprising a container (12) fitted with a removable cover and which contains the ion exchange resins, characterized in that it comprises modules rigid (1,2,3,4,5,6) each of which contains only a cationic resin or an anionic resin, and in that these modules are arranged so as to alternate a cationic resin module and a resin module anionic.   2. Device according to claim 1 characterized in that a module (1) of cationic resin is placed first at the bottom of a stack of modules (1-6) of resins, then above a module (2) of anionic resin, and so on, continuing alternating to the top of the container (12).   3. Device according to one of claims 1 and 2, characterized in that the modules (1-6) of resins are at least six in number, at the rate of three modules of cationic resin and three modules of anionic resin.   4. Device according to one of claims 1 to 3 characterized in that the cationic resins and the anionic resins respectively form substantially 50% by volume of all the resins.   5. Device according to one of claims 1 to 4 characterized in that each module (1-6) is pierced with at least one hole (31) for filling and emptying of ion exchange resin.   6. Device according to one of claims I to 5, characterized in that the modules (1-6) are cylindrical or have any other shape depending on the container (12), and are provided at their lower part with a section cylindrical threaded (7) allowing their fixing by screwing in a tapped part (7a) corresponding arranged on the lower module.   7. Device according to one of claims I to 6 characterized in that the container (12) consists of two superimposed half-containers (13, 14), identical and provided with removable securing means, each half-container comprising the same number of rigid modules (1-3; 4-6) containing the ion exchange resins.   8. Device according to one of claims 1 to 7 characterized in that each module, of different colors (1 ... 6), comprises at its base and at its upper part a grid (27a, 27b) of resin support , and is pierced with gates (8) for pressure distribution.   9. Device according to one of claims 1 to 8 characterized in that seals (9) are interposed between the modules (1-6).   10. Device according to one of claims 7 to 9, characterized in that the securing means comprise two respective flanges (19, 21) arranged at the base of the upper half-container (13) and at the upper end of the lower half-container (14), profiled so as to be oriented respectively upwards and downwards by defining a frustoconical surface projecting transversely from the container, a seal (22) is formed between these edges, and a collar ( 24) of closure supported by one of the half-containers, consisting of two half-15 semi-cylindrical straps (24a, 24b) profiled so as to be able to apply each by force on a half-circumference of the frustoconical bearing surface of the two ledges, ensuring the locking of the two half-containers (13, 14) one on the other.   11. Device according to one of claims 1 to 10 characterized in that depolluting filters are interposed between the modules (1-6) in order to obtain demineralized water of higher purity, more sterile or for certain very specific applications .