Fluid treatment installation operating under pressure using a fluidized bed of adsorbent media particles.

Abstract

Installation for the treatment of a fluid comprising a reactor (1) housing a bed of adsorbent media particles, injection and distribution means (2) for the fluid to be treated arranged in the lower part of said reactor (1) intended to form an upward flow of fluid within said reactor (1) and enabling the fluidization and expansion of said bed of adsorbent media particles, recovery means (3) for the fluid having passed through said bed of adsorbent media particles thus fluidized, characterized in that said reactor (1) is a closed reactor forming an enclosure enabling said treatment to be carried out under pressure, said enclosure having a bottom (11) housing said injection and distribution means (2) for the fluid to be treated, a central body (12) essentially cylindrical forming a fluidization column,a peripheral body (14) essentially cylindrical defining an annular chamber (15) around said central body (12) essentially cylindrical delimiting a fluidization column, said annular chamber (15) housing at least one layer of a granular or powdery material, a curved lid (13) forming a deflector allowing said upward flow to be transformed into a homogeneous downward flow and directing said downward flow towards said recovery means (3) via said annular chamber (15). Figure to be published with the abbreviation: Figure 2,

Description

Title of the invention: Fluid treatment installation operating under pressure using a fluidized bed of adsorbent media particles. Scope of the invention

[0001] The present invention relates to the field of treatment of fluids such as water by passing through a reactor containing adsorbent media particles.

[0002] More specifically, the invention relates to an installation implementing such particles in the form of a fluidized bed.

[0003] The present invention is adapted to the removal of organic substances, micropollutants and / or metallic ions in water using activated carbon as an adsorbent medium. Previous art

[0004] In the prior art, various installations exist for the treatment of fluids such as water, employing fluidized beds of adsorbent media particles that allow for the attachment of different types of undesirable compounds present in the fluids in question. Such installations maximize the adsorbent action of these particles while minimizing the pressure losses caused by the fixed particle beds.

[0005] The minimum fluidization velocity of a media bed composed of solid particles is the minimum velocity that a fluid flowing from bottom to top must have to allow for a slight movement of the particles, which then become suspended. It depends on the size and density of the solid particles as well as the viscosity of the fluid. When the fluid velocity exceeds the minimum fluidization velocity, the bed of solid particles undergoes an expansion phenomenon in the reactor, characterized by an expansion rate. The expansion rate corresponds to the increase in the bed height during the passage of the fluid at the fluidization velocity compared to the bed height at rest. For a given particle bed, the expansion is equivalent to the suspension of the particles. The particle expansion changes according to the upward velocity.By progressively increasing this speed, the expansion progresses from a state of immobility to a state where the particles become suspended, reaching a height that can be up to twice the initial height (rest height). In this case, the particles become independent of each other.

[0006] In practice, in order to utilize all the mass of activated carbon present in the reactor, the activated carbon bed must generally be fluidized at an expansion rate that Theoretically, this can be between 10 and 100%. Below 10%, the specific surface area of ​​the medium may not be fully utilized for adsorption.

[0007] Thus, the implementation of installations incorporating such fluidized beds requires increased control of the upward fluid velocity to find the least bad compromise, for a given particle size range, between, on the one hand, sufficient bed expansion, particularly of larger particles, and, on the other hand, limited leakage of smaller particles. However, it is virtually impossible to favor one without compromising the other.

[0008] Patent application FR2874913 describes a water treatment process using a fluidized activated carbon bed in a reactor, in which the fluidization rate of the activated carbon and its characteristics must be precisely chosen to ensure gravity separation, in the upper part of the reactor, between the activated carbon particles and the fluid, the treated fluid essentially free of activated carbon being recovered by overflow at the outlet of the reactor.

[0009] Activated carbon leakage is particularly detrimental as it leads to additional costs, notably due to the need to reinject new activated carbon to compensate for this loss. Furthermore, it results in an unnecessary overload of suspended solids (SS) in the treated fluid, an overload that must be absorbed by filters located downstream of the upflow treatment process, which therefore tend to clog more quickly.

[0010] French patent application FR3081458 describes a method for treating a fluid using an upflow reactor containing a fluidized bed of adsorbent media particles and having, in its upper part, fluid deflection means designed to reduce the velocity of the upflow of fluid and thus create a fluid calm zone. The adsorbent media particles, particularly the smaller ones, come into contact with the deflection means and, due to the slowing of the upflow velocity at the deflection means, fall back to the bottom of the reactor. The downstream zone is therefore almost free of adsorbent media particles, and a treated fluid free of suspended adsorbent media particles can be recovered.

[0011] All these installations have in common that they operate at atmospheric pressure. The treated water in the fluidized bed of adsorbent media particles is therefore collected by overflow at the top of the structures.

[0012] This operation is gravity-driven and at atmospheric pressure. However, it is often necessary to convey the fluid recovered by overflow to additional treatment stages. Thus, in the context of water purification, such stages These measures may include filtration, disinfection or remineralization in order to meet regulatory levels.

[0013] To reach the additional stages in question, the water recovered by overflow at the top of the installations must therefore be pumped to them, which entails the need to use additional equipment which increases the cost of the installations and their implementation.

[0014] To avoid the need for such pumping, altimetric calibration constraints can also be implemented in certain cases. However, site constraints do not always allow for this.

[0015] It should also be noted that, in the context of implementing prior art activated carbon fluidized bed reactors for water treatment, a difficulty encountered lies in the variability of the concentration of pollutants to be adsorbed present in the water to be treated. Thus, some waters may exhibit pollution spikes that can be quite difficult to predict. To allow for the treatment of these pollution spikes, it is often necessary to add significant quantities of activated carbon to the reactors as a preventive measure. Such overdosing implies an increase in the quantities of activated carbon used and therefore an increase in the implementation costs of the installations. Sensors and automated systems can also be implemented to better manage these unexpected pollution spikes. However, such equipment also increases the cost of the installations and their implementation. Objectives of the invention

[0016] An objective of the invention is to propose a fluid treatment installation on a fluidized bed of adsorbent media particles allowing to do without the use of intermediate pumps or altimetric calibration constraints to convey the fluid which has passed through the fluidized bed to at least one subsequent treatment stage.

[0017] An objective of the invention is to describe such an installation which, in at least some embodiments, incorporates at least one further processing step and which has an optimized footprint.

[0018] Yet another objective of the present invention which, in at least some embodiments, incorporates at least one subsequent processing step and enables optimized processing speeds in that step.

[0019] Another objective of the present invention is to describe a system comprising several such installations having common means of supplying treated water. Description of the invention

[0020] These objectives, as well as others which will appear subsequently, are achieved thanks to the invention which relates to an installation for the treatment of a fluid comprising: - a reactor housing a bed of adsorbent media particles; - means for injecting and distributing the fluid to be treated, arranged in the lower part of said reactor, intended to form an upward flow of fluid within said reactor and enabling the fluidization and expansion of said bed of adsorbent media particles; - means for recovering the fluid that has passed through said bed of fluidized adsorbent media particles, characterized in that said reactor is a closed reactor forming an enclosure for carrying out said treatment under pressure, said enclosure having: - a base housing the said means of injection and distribution of the fluid to be treated; - a central body essentially cylindrical forming a fluidization column; - preferably a peripheral body essentially cylindrical defining an annular chamber around said central body essentially cylindrical delimiting a fluidization column, said annular chamber receiving at least one layer of a granular or powdery material; - a curved cover forming a deflector allowing the upward flow to be transformed into a homogeneous downward flow and the downward flow to be directed towards the recovery means preferentially via the annular chamber.

[0021] To the Applicant's knowledge, providing fluidization of a bed of adsorbent media particles in a closed-loop upflow reactor had not been proposed or suggested in the prior art. This solution allows the treatment to be carried out not at atmospheric pressure but at a higher pressure, thus avoiding any pressure drop in the fluid at its outlet from the reactor. Therefore, the invention makes it possible to eliminate the need for intermediate pumping of this fluid to convey it to one or more additional treatment stages and / or to eliminate any constraints on the elevation of this reactor for such conveyance without pumping. Compared to the prior art, such an installation is therefore more economical to build and also to operate, as the energy that would be required for intermediate pumping operations is not used.

[0022] The lid closing the reactor of the installation according to the invention makes it possible to reverse the direction of the fluid flow, that is to say, to transform the upward flow of fluid that has passed through the fluidized bed of adsorbent media particles into a downward fluid flow towards the discharge means. This downward flow can then directly supply one or more additional treatment stages without the need for pumping or without needing to place the reactor at an altitude higher than that of a A device for such additional treatments. Regarding this lid, it should be noted that its curved shape facilitates this function.

[0023] Furthermore, advantageously, the invention makes it possible to add within the same installation one or more additional treatment stages of the fluid which has passed through the fluidized bed of adsorbent media particles by providing an essentially cylindrical peripheral body defining an annular chamber around said essentially cylindrical central body forming a fluidization column.

[0024] Such an annular chamber provided around the central body makes it possible to optimize the footprint of the installation according to the invention compared to those of installations which would include on the one hand a prior art reactor operating at atmospheric pressure, on the other hand a device for the further treatment of the fluid from this reactor, and finally altimetric calibration constraints or pipes equipped with pumps between such a reactor and such a device.

[0025] Such a configuration also makes it possible to reduce the cost of installation.

[0026] Preferably, the adsorbent media particles are grains or micrograins selected from activated carbon, resin, clay, zeolite, manganese dioxide, iron oxyhydroxide, or mixtures thereof.

[0027] Advantageously, said powdery or granular material present in said annular chamber is chosen from the group consisting of adsorbent materials, filtration materials, remineralization materials, materials with catalytic effect (such as, for example, manganese oxide...).

[0028] When dealing with an adsorbent material, it can be the same as that used in the fluidization column. Thus, the presence of this additional adsorbent material in the annular chamber can eliminate the need to overdose the adsorbent material in the fluidization column, particularly to prevent pollutant spikes in the incoming fluid to be treated, and allow the use of sensors or automated systems to minimize these overdoses. The redundant treatment of the fluid by the adsorbent medium, first in the fluidization column and then in the annular chamber, will also offer maximum treatment reliability.

[0029] When the material used in the annular chamber is a filtration material, it can be used to retain any suspended matter present in the fluid at its exit from the fluidized bed of adsorbent media particles, and in particular to retain this media when it has leaked from the fluidization column.

[0030] According to a particularly interesting variant, said annular chamber accommodates at least two layers of powdered or granular materials. The choice of these materials will be made according to the resource to be processed.

[0031] Thus, for example, said annular chamber accommodates a layer of sand, and at least one layer of a material chosen from granular activated carbon, anthracite, sand, manganese oxide, limestone provided(s) above said layer of sand.

[0032] Advantageously, said means for recovering the fluid having passed through said fluidized bed and possibly through said at least one layer of powdery or granular material provided in said annular chamber include a discharge pipe provided in the lower part of said reactor.

[0033] Preferably, the installation includes means for washing said at least one layer of granular or powdery material provided in said annular chamber. Such washing will preferably be carried out counter-currently by passing a washing fluid in an upward current through the annular chamber.

[0034] According to one variant, said annular chamber includes a perforated floor on which rests said at least one layer of granular or powdery material, means for injecting wash water provided under said floor, means for recovering dirty wash water provided in the upper part of said annular chamber.

[0035] Advantageously, said means for recovering dirty wash water include a peripheral chute.

[0036] Also advantageously, the installation includes additional means selected from means for injecting new adsorbent media particles, means for extracting used adsorbent media particles and means for recirculating the treated fluid.

[0037] The installations according to the invention may be combined into a system by grouping two or more that can operate in parallel. The means for supplying the water to be treated to the reactors of these installations may be common and equipped with a valve system allowing the water to be distributed to one or more of these reactors. Brief description of the figures

[0038] [Fig. 1]: The [Fig. 1] represents a cross-sectional view of a first embodiment of an installation according to the present invention;

[0039] [Fig.2]: [Fig.2] represents a cross-sectional view of a second embodiment of an installation according to the present invention;

[0040] [Fig.3] : The [Fig.3] represents a cross-sectional view of a third embodiment of an installation according to the present invention. Description of the implementation methods

[0041] The invention, as well as the various advantages it presents, will be better understood from the following description of different embodiments given with reference to the figures. First method of implementation

[0042] With reference to [Fig.1], an installation includes a reactor 1 housing a bed of adsorbent media particles, for example, coagulated powdered activated carbon, granules, or microgranules.

[0043] This installation also includes means 2 for injecting under pressure a fluid to be treated such as polluted water into the lower part of this reactor 1 allowing to form an upward flow of water within it at a speed allowing the fluidization and expansion of the activated carbon bed while avoiding leakage of this material out of reactor 1.

[0044] These injection means include a main pipeline 21 and a plurality of auxiliary pipelines 22 connected to it, allowing the water to be distributed essentially uniformly in the reactor 1.

[0045] Means 3 for recovering water that has passed through the fluidized bed of adsorbent media particles, essentially free of pollutants adsorbed on them, are provided in the upper part of reactor 1. These means 3 comprise a funnel-shaped element 31 connected to a discharge pipe 32.

[0046] In the installation shown, reactor 1 is equipped with means 111 for supplying adsorbent media particles. The reactor also comprises a bottom 11, a cylindrical central body 12 delimiting a fluidization column housing the fluidized activated carbon bed, and a curved lid 13. An air vent 131 is mounted on the lid 13. This reactor 1 thus forms a closed enclosure by definition, allowing for pressurized treatment of the water passing through it.

[0047] The movement of water within reactor 1 during its treatment therein is symbolized by the arrows shown on [Fig.1].

[0048] The water to be treated arrives under pressure in reactor 1 via pipe 21 of the means 2 provided in the bottom 11 thereof and is distributed essentially uniformly in an upward flow within reactor 1 by pipes 22 connected to this pipe 21. Thanks to the pressurized arrival of this water in reactor 1, the activated carbon bed present therein is expanded and fluidized. The fluidization velocity is chosen to allow the expansion of the fluidized bed 4 to a certain height H from the bottom 11 of the reactor while maintaining above the fluidized bed 4 a zone 5 essentially free of activated carbon.

[0049] After passing through the fluidized bed 4 of activated carbon, the pressurized water strikes the reactor lid 13, which acts as a deflector and reverses the direction of the water flow, transforming it into a downward flow and directing it towards the funnel-shaped element 31 and then the pipe 32 of the discharge means 3. Arriving still under pressure in these discharge means 3, the The water flow then experiences no break in load at its exit from reactor 1 and can then be conveyed to one (or more) additional treatment stage without resorting to pumping water to it and without making this conveyance subject to altimetric calibration constraints between reactor 1 and a device for the implementation of this additional stage. Second embodiment

[0050] With reference to [Fig.2], a second embodiment of the invention includes a reactor 1 housing a bed of adsorbent media particles, for example, coagulated powdered activated carbon, granules or microgranules.

[0051] This installation also includes means 2 for injecting under pressure a fluid to be treated such as polluted water into the lower part of this reactor 1 allowing to form an upward flow of water within it at a speed allowing the fluidization and expansion of the activated carbon bed while avoiding leakage of this material out of reactor 1.

[0052] These injection means include a main pipeline 21 and a plurality of auxiliary pipelines 22 connected to it, allowing the water to be distributed essentially uniformly in the reactor 1.

[0053] Means 3 for recovering water that has passed through the fluidized bed of adsorbent media particles are provided in the lower part of reactor 1. These means 3 include a discharge pipe 33.

[0054] In the installation shown in [Fig.2], the reactor 1 comprises a bottom 11, a cylindrical central body 12 delimiting a fluidization column and a cylindrical peripheral body 14 defining an annular chamber 15 around said cylindrical central body 12.

[0055] The annular chamber 15 accommodates a layer 6 of granular or powdered material, such as sand, for filtering the water from the fluidization column to reduce its suspended solids content. This layer 6 of granular or powdered material rests on a perforated floor 16 defining a space 17 with the bottom 11 of the reactor 1, which communicates with the drain pipe 33 of the discharge means 3. The reactor also includes a curved lid 13. An air vent 131 is mounted on the lid 13. Means for loading the granular or powdered material into the annular chamber 15 are provided (not shown).

[0056] This reactor 1 therefore forms a closed enclosure by definition allowing treatment under pressure of the water passing through it.

[0057] The movement of water within reactor 1 during its treatment in it is symbolized by the arrows shown on [Fig.2].

[0058] The water to be treated arrives under pressure in reactor 1 via pipe 21 of the means 2 provided in the bottom 11 thereof and is distributed essentially uniformly in an upward flow within reactor 1 by pipes 22 connected to this pipe 21. Thanks to the pressurized arrival of this water in reactor 1, the activated carbon bed present therein is expanded and fluidized. The fluidization velocity is chosen to allow the expansion of the fluidized bed 4 to a certain height H from the bottom 11 of the reactor while maintaining above the fluidized bed 4 a zone 5 essentially free of activated carbon.

[0059] After passing through the fluidized bed 4 of activated carbon, the pressurized water comes against the cover 13 of the reactor which acts as a deflector and allows the direction of the water flow to be reversed to transform it into a downward flow, this downward flow being homogeneous, that is to say able to be distributed homogeneously in the layers of materials present in the annular chamber, and to direct it towards the pipe 33 of the evacuation means 3 via the annular chamber 15 containing the layer of sand 6.

[0060] During its transit through the fluidized bed 5 and then through the sand layer 6 and until its exit from the reactor 1, the water flow does not experience any break in charge.

[0061] The configuration of the annular chamber 15 around the cylindrical body 12, which delimits the activated carbon fluidization column, optimizes the installation's footprint. This installation thus has a smaller footprint than prior art installations combining an activated carbon fluidized bed reactor operating at atmospheric pressure and a sand filter connected by a pipeline equipped with a pump, or arranged relative to each other with altimetric alignment constraints.

[0062] Any fine particles of activated carbon or suspended matter escaping from the fluidized bed can be treated in the annular chamber.

[0063] This pressurized configuration also makes it possible to consider higher filtration speeds than those which are classically implemented in a separate filtration device receiving water from a fluidized bed activated carbon reactor operating at atmospheric pressure.

[0064] The height of the annular filtration zone, linked to the height of the central fluidized bed, also allows the use of higher treatment velocities. Third embodiment

[0065] This third embodiment retains the characteristics of the embodiment shown in [Fig.2] with the following differences.

[0066] In the annular chamber 15, two layers of granular or powdery material 6 are provided instead of one. These layers rest on the perforated floor 16 of the annular chamber 15 consists of a layer 6a made of granular or microgranular activated carbon and, provided below this, a layer 6b made of sand.

[0067] The activated carbon layer 6a allows the adsorption of pollutants already at least largely carried out in the fluidization column by the fluidized activated carbon to be completed and thus to treat any pollution peaks when they occur or at the very least to offer redundancy of the treatment by adsorption allowing to secure it.

[0068] The 6b layer of sand, for its part, makes it possible to reduce the suspended matter content of the water before it exits the reactor.

[0069] Furthermore, the annular chamber 15 is equipped with means for washing the layers of material provided therein. These means 18 include an injection pipe for a washing fluid such as water, opening into the space 17 provided under the perforated floor 16, and a drain pipe 19 for the dirty wash water provided in the upper part of the annular chamber 15. To facilitate the drainage of the wash water, the annular chamber is provided in its upper part with a peripheral gutter 20 to collect it.

[0070] When the material layers 6a and 6b become clogged, the supply of water to the installation to be treated by means 2 can be interrupted and a washing fluid can be injected into these layers 6a and 6b, according to an upward flow symbolized by the arrows in the dotted line shown on [Fig.3], so as to unclog them.

[0071] The installations described above may be associated into a system by grouping two or more that can operate in parallel, of the same or different embodiments. The means of supplying water to be treated to the reactors of these may be common and provided with a system of valves allowing the water to be treated to be distributed into one or more of these reactors.

Claims

Demands

1. Installation for the treatment of a fluid comprising: - a reactor (1) housing a bed of adsorbent media particles; - injection and distribution means (2) for the fluid to be treated, arranged in the lower part of said reactor (1), intended to form an upward flow of fluid within said reactor (1) and enabling the fluidization and expansion of said bed of adsorbent media particles; - recovery means (3) for the fluid that has passed through said bed of adsorbent media particles thus fluidized, characterized in that said reactor (1) is a closed reactor forming an enclosure allowing said treatment to be carried out under pressure, said enclosure having: - a bottom (11) housing said injection and distribution means (2) for the fluid to be treated; - a central body (12) essentially cylindrical forming a fluidization column;- a peripheral body (14) essentially cylindrical defining an annular chamber (15) around said central body (12) essentially cylindrical delimiting a fluidization column, said annular chamber (15) receiving at least one layer of a granular or powdery material; - a curved cover (13) forming a deflector allowing said upward flow to be transformed into a homogeneous downward flow and directing said downward flow towards said recovery means (3) via said annular chamber (15); - means for washing said at least one layer of granular or powdery material provided in said annular chamber (15).

2. Installation according to claim 1 characterized in that the adsorbent media particles are grains or micrograins selected from activated carbon, resin, clay, zeolite, manganese dioxide, iron oxyhydroxide, or mixtures thereof.

3. Installation according to claim 1 or 2 characterized in that said powdered or granular material present in said annular chamber (15) is selected from the group consisting of adsorbent materials, filtration materials, remineralizing materials, catalytic effect materials.

4. Installation according to any one of claims 1 to 3 characterized in that said annular chamber (15) accommodates at least two layers (6a, 6b) of powdered or granular materials.

5. Installation according to claim 4 characterized in that said annular chamber accommodates at least one layer (6a) of a material selected from granular activated carbon, anthracite, sand, manganese oxide, limestone provided(s) above a layer of sand (6b).

6. Installation according to any one of the preceding claims, characterized in that said means for recovering (3) the fluid having passed within said fluidized bed and possibly within said at least one layer of powdery or granular material provided in said annular chamber (15) comprise a discharge pipe (33) provided in the lower part of said reactor.

7. Installation according to any one of claims 1 to 6 characterized in that said annular chamber (15) comprises a perforated floor (16) on which rests said at least one layer of granular or powdery material, means for injecting wash water (18) provided under said floor (16), means for recovering dirty wash water provided in the upper part of said annular chamber (15).

8. Installation according to claim 7 characterized in that said means for recovering dirty wash water include a peripheral chute (20).

9. Installation according to any one of claims 1 to 8 characterized in that it comprises additional means selected from means for injecting new adsorbent media particles, means for extracting used adsorbent media particles and means for recirculating the treated fluid.

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