Device and method for purifying a fluid in the liquid phase

Abstract

One aspect of the invention relates to a device for purifying a fluid in the liquid phase, which device comprises: - a nozzle for dispensing the fluid in the form of droplets in an atmosphere; - a wall of a condenser; and - a membrane permeable to the fluid in the gas phase and impermeable to the fluid dispensed in the form of droplets in the atmosphere, the membrane being arranged between the nozzle and the wall of the condenser; wherein the wall of the condenser and the membrane define a first space, and wherein the condenser comprises a refrigerant flow circuit, the wall of the condenser separating the refrigerant flow circuit from the first space, the wall of the condenser being impermeable to the fluid in the liquid phase and in the gas phase and being configured to condense the fluid in the gas phase that has passed through the membrane into a purified fluid liquid phase.

Description

DESCRIPTION TITLE: Device and method for purifying a fluid in liquid phase TECHNICAL FIELD OF THE INVENTION

[0001] The technical field of the invention is that of the purification of a liquid.

[0002] In particular, the invention relates to the production and collection of purified fluid in the liquid state from the same unpurified fluid (e.g. containing a solute), by thermal distillation. For example, the invention relates to the production and collection of purified water from water containing a solute (e.g. salt water or mineral-laden water or polluted water). TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0003] There are so-called "semi-permeable" membranes, defined as porous membranes, permeable to gases and impermeable to liquids. These membranes are used between two environments of different temperatures, the environment at the higher temperature being referred to as the "hot environment" and the environment at the lower temperature being referred to as the "cold environment", conventionally.

[0004] The temperature difference between the hot and cold medium induces a difference in vapor pressure between these two mediums, and this results in an exchange between the two mediums, which through, or perpendicular to a semi-permeable membrane takes place in the vapor phase, from the hot medium to the cold medium. This vapor, after crossing a semi-permeable membrane, condenses in the cold medium and this results in a dilution of the liquid cold medium by the condensate of this vapor, which has become liquid.

[0005] To use this property industrially, a flow of cold fluid is added to the cold medium and a flow of hot fluid to the hot medium, making it possible to produce, from a hot liquid at a first concentration of a first solute, a cooled and more concentrated hot liquid in the hot hydraulic circuit after having passed through the hot medium delimited by the membrane and a heated and diluted cold liquid. This structure constitutes an exchanger of heat and purified fluid between the hot medium and the cold medium considered, known from the prior art.

[0006] As is known, there are devices comprising a nozzle and a membrane with low mechanical resistance, immersed in a gas, to dehumidify or humidify the gas but they are unsuitable for use in a purified water generator.

[0007] In a known manner, it is also possible to use in the hot hydraulic circuit, a first pressure reducer or hot pressure reducer, such as for example a first nozzle or hot nozzle, and in the cold hydraulic circuit a second pressure reducer or cold pressure reducer, such as for example a second nozzle or cold nozzle, to operate at identical pressure, for example at atmospheric pressure, on each side of the membrane so as to allow the use of any semi-permeable membrane, in particular thin membranes, easily produced in industrial quantities but fragile and supporting only a small difference in pressure between the media which they separate.

[0008] In practice, however, in nozzle devices, which operate by diluting the cold medium via the addition of liquid vapor condensate, particularly water, the production of purified liquid is only possible if purified liquid is circulated in the cold hydraulic circuit, which requires an initial volume of purified liquid. These systems are therefore not suitable for the production of a purified liquid, particularly purified water, but only for the addition of purified liquid, particularly purified water, to a hydraulic circuit which already contains it.

[0009] There is therefore a need to produce and collect a purified liquid, for example purified water. SUMMARY OF THE INVENTION

[0010] The invention offers a solution to the problems mentioned above, by proposing a device for purifying fluids in a simple and efficient manner, while consuming little energy.

[0011] One aspect of the invention thus relates to a device for purifying a fluid in the liquid phase. The device comprises: a nozzle for distributing said fluid in the form of drops into an atmosphere; a wall of a condenser; and a membrane permeable to said fluid in the gas phase and impermeable to said fluid distributed in the form of drops in the atmosphere, the membrane being arranged between the nozzle and the wall of the condenser;

[0012] wherein the condenser wall and the membrane define a first space, the membrane separates the first space from a second space comprising the nozzle, and wherein the condenser comprises a circulation circuit for a refrigerant fluid, the condenser wall separating the circulation circuit for the refrigerant fluid and said first space, the condenser wall being impermeable to the fluid in the liquid phase and in the gas phase and being configured to condense the fluid in the gas phase passed through the membrane into a liquid phase of purified fluid.

[0013] By "nozzle" is meant an element capable of dividing a liquid into drops and expelling the drops into an atmosphere (in other words, distributing the liquid in the form of drops into an atmosphere or medium). By condenser is meant a device capable of condensing (or liquefying) vapor. By "refrigerant" is meant a fluid capable of cooling, typically having a temperature lower than the dew point temperature of the vapor circulating in the space between the membrane and the condenser.

[0014] Such a device makes it possible to implement thermal distillation, that is to say an evaporation-condensation cycle of a fluid containing a solute or a non-volatile component or less volatile than the fluid, the concentration of the solute increasing in the part of the fluid which does not evaporate during the cycle and decreasing (or even being completely eliminated) in the part of the fluid which evaporates and then condenses. Thus, the term "purified fluid" or "pure fluid" designates the fluid obtained by evaporation-condensation during thermal distillation. The part of the fluid which does not evaporate is a fluid with a higher concentration of solute, in other words even less purified.

[0015] The fluid that we want to purify is called "unpurified fluid" or "non-pure fluid" and can be, for example, water containing minerals such as calcium, magnesium or salt (hereinafter referred to simply as "salts"), for example, water from a distribution network, sea water or polluted water.

[0016] By fluid, we mean a fluid in liquid phase (also called simply “liquid”) or in gaseous phase (also called “gas” or “vapor”).

[0017] Such a device, when supplied with the unpurified fluid and the refrigerant fluid, advantageously makes it possible to purify the unpurified fluid and to recover purified fluid from the unpurified fluid, in a simple and efficient manner.

[0018] Indeed, drops of unpurified liquid brought to a first temperature (unpurified fluid "hot", in the sense of "hotter than the condenser wall) can be distributed via the nozzle into an atmosphere between a pressurized inlet and an atmospheric pressure outlet of the nozzle, which causes vapor to form in the atmosphere in addition to the drops. The vapor corresponds to a gaseous phase of the purified fluid. A portion of the vapor naturally migrates to the condenser (or cold trap) which is brought to a second temperature lower than the first temperature, to be condensed at atmospheric pressure into drops of purified liquid on a cold impermeable wall of the condenser.

[0019] Indeed, when a temperature difference is created between a hot liquid (mixture of components or not) and a liquid or a surface colder than this liquid and colder than the dew point temperature of the atmosphere near the colder surface or the colder liquid, a difference in partial vapor pressure appears, constituting the driving force of an evaporation and condensation process. Thus, vapor from the liquid formed on the surface of the hot liquid migrates to the liquid or surface colder than its condensation temperature and condenses. This phenomenon cools the hot liquid because the heat necessary for evaporation is taken from it and provides heat to the cold liquid or the cold wall because the heat released by condensation is transferred to it.

[0020] The practical implementation of this physical principle faces several technical and functional difficulties. The risk of projection of hot liquid which can reach the cold liquid or the cold surface and mix with the condensates is a known risk of contamination or loss of purity of the condensates.

[0021] In the above device, the semi-permeable membrane arranged between the nozzle and the condenser wall allows the separation of the purified fluid vapor from the drops of unpurified fluid, so that only a purified part of the fluid distributed in the form of drops reaches the space delimited between the condenser wall and the membrane, so that the purified part of the fluid is not "contaminated" with the unpurified fluid which circulates on the other side of the membrane (on the side where the nozzle). This membrane operates at equal pressure (for example, at atmospheric pressure) on both sides, and is therefore mechanically under little stress. Thus, it does not require special mechanical properties, which reduces its production cost.

[0022] It is thus understood that the term "impermeable to fluid dispensed in the form of drops" corresponds, in the context of the invention, to a property of the membrane according to which the drops of liquid do not pass through the membrane when the device is in operation (and in particular when fluid is dispensed in the form of drops by the nozzle). For example, a membrane that is non-absorbent for drops of liquid, a membrane in a water-repellent material or covered with a water-repellent material, which do not allow drops of liquid to pass through, fall within the scope of the present invention. In particular, it is noted that the membrane is not necessarily impermeable to the liquid: for example, if it is subjected to significant liquid pressure (sending a jet of liquid against the membrane for example), it may become permeable and allow the liquid to pass through.On the other hand, it is important that the membrane is impermeable to liquid drops, so as to allow only pure liquid vapor to pass into the space between the condenser and the membrane, and not to allow unpurified liquid to pass into this space.

[0023] Of course, the device may comprise a plurality of the above elements, as described with reference to Figure 1. It is thus possible to increase the exchange surface in a modular manner by adding as many channels and nozzles as necessary to carry out the heat and mass exchanges.

[0024] In the following, the first space and the second space may also be called "channels" or "fluidic channels". By "channel" or "fluidic channel" is meant an element or a set of elements capable of allowing circulation of a fluid in the gas phase or flow or circulation of a fluid in the liquid phase. A fluidic channel is capable of transporting a vapor of a fluid in the gas phase and / or collecting drops of a liquid by trickling along said channel. A fluidic channel may in particular be of a thickness less than or much less than its length and its width, when it is produced by mounting two membranes or two walls similar to canvases mounted on frames parallel to each other and spaced apart by the thickness of the channel, in the manner of the frames or shelves of a beehive, a seal is also obtained between the frames, by elements connecting the frames together, depending on the thickness of the channel.

[0025] For example, the nozzle may be a spray nozzle. In this embodiment, the fluid is sprayed by the spray nozzle in fine droplets, particularly in a direction parallel to the membrane. The fine droplets promote evaporation of the liquid, while limiting the pressure on the membrane.

[0026] For example, the nozzle may be a jet nozzle. In this embodiment, the fluid is projected from the spray nozzle in a jet, particularly in a direction parallel to the membrane.

[0027] Other embodiments are possible. For example, the nozzle may be a hollow rod (or cane) (or pipe) pierced with small holes along its length through which the liquid is dispensed in the form of drops.

[0028] In one or more embodiments, the membrane includes a first face facing the first space and a second face facing the second space, and the membrane is configured to operate at equal pressure on its first face and on its second face.

[0029] For example, said pressure may be atmospheric pressure.

[0030] In one or more embodiments, the membrane and the condenser wall extend in substantially vertical planes.

[0031] According to these embodiments, the membrane and the condenser wall are flat (it is noted that undulations on the surface of the membrane are possible, as are patterns on the condenser wall). By "substantially vertical" it is understood that the membrane and the condenser wall can each form an angle of between 70° and 110° with the ground.

[0032] Such a configuration advantageously makes it possible to maximize the heat exchange and condensation surfaces, while minimizing the stresses on the membrane.

[0033] In these embodiments, if the nozzle is a rod pierced with small holes, the rod may extend substantially horizontally so as to dispense drops of fluid into the second space.

[0034] In one or more embodiments, the device further comprises a first fluid distributor for supplying the nozzle with said fluid in liquid phase and a second fluid distributor for supplying the refrigerant circulation circuit with the refrigerant.

[0035] The first distributor (also called "hot liquid distributor" or "hot water distributor" hereafter) and the second distributor (also called "cold / refrigerant liquid distributor" or "cold water distributor" hereafter) are used to supply the device with the fluid dispensed by the nozzle and the refrigerant fluid. As detailed later, these two distributors can be connected (possibly via other elements) so that the same fluid can be both the fluid dispensed in the form of drops and the refrigerant fluid.

[0036] In one or more embodiments, the device comprises a collector configured to collect at least a portion of the fluid dispensed as drops from the nozzle and flowing into the second space.

[0037] This collector, also called "hot liquid collector" or "hot water collector" hereinafter, advantageously allows the recovery of the part of the fluid distributed in the form of drops by the nozzle which has not passed through the membrane in the form of vapor. This recovery can have several uses. For example, the fluid thus collected can be thrown out of the device when it becomes too "impure" (for example too loaded with salts). The collected fluid can also be reused as a refrigerant liquid after cooling, as detailed below. It is noted that the liquid collected by the hot liquid collector is less hot than the liquid at the nozzle outlet, because this liquid is cooled by evaporation during its passage in the second space.

[0038] In one or more embodiments, the refrigerant circulation circuit, the nozzle and the second space belong to the same fluid circuit.

[0039] By "fluidic circuit" is meant a circuit for circulating a fluid or, in other words, a circuit allowing a fluid exchange between the elements. Thus, according to these embodiments, there may be a circulation of the same fluid in the refrigerant circulation circuit and the second space. In other words, the fluid circulating in the second space may then circulate in the refrigerant circulation circuit (possibly after passing through other elements of the device, for example a cooling system) and / or the fluid circulating in the refrigerant circulation circuit can then be distributed into the second space by the nozzle.

[0040] In particular, the fluid circuit may be a "closed fluid circuit" (or "circuit looped on itself from a fluidic point of view"), that is to say a fluid circuit in which at least part of the fluid at the outlet of the circuit is reinjected into an inlet of the circuit. It is noted that the term "closed circuit" does not exclude the possibility that the circuit comprises means for supplying and / or withdrawing fluid. In other words, part of the fluid circulating in the closed circuit may be withdrawn (for example, liquid with a high salt content) and / or fluid from outside the circuit (for example, liquid with a lower salt content) may be added to the closed circuit.

[0041] Other embodiments are possible. For example, the fluid circulating in the second space can be reinjected into the refrigerant circulation circuit at the outlet of which it can be evacuated. According to another example, the fluid circulating in the refrigerant circulation circuit can then be distributed into the second space by the nozzle, and the remaining part of the liquid in the second space can then be evacuated. These examples do not correspond to closed fluid circuits, in the sense that the circuit is not looped on itself, but there is indeed a fluid exchange between the refrigerant circulation circuit, the nozzle and the second space, which therefore belong to the same fluid circuit within the meaning of the invention.

[0042] To implement such a fluid circuit, the refrigerant circulation circuit may comprise an inlet and an outlet, and the device may further comprise a first connection circuit between the outlet of the refrigerant circulation circuit and the first fluid distributor.

[0043] By "connection circuit" between two entities is meant an element or a set of elements allowing a fluid to circulate from one of the entities to the other entity. A connection circuit may comprise for example one or more pipes, as well as one or more intermediate systems, an intermediate system comprising for example an inlet through which the fluid can enter the system, a circulation circuit in which the fluid circulates and a outlet through which the fluid leaves the system and an outlet into which the fluid can enter - such a system can be for example a fluid heating or cooling system.

[0044] Thus, according to one embodiment, the first connection circuit may comprise a heating system configured to heat a fluid circulating in said first connection circuit, a connection pipe connecting the outlet of the refrigerant circulation circuit to said heating system and a connection pipe connecting said heating system to the first fluid distributor.

[0045] Such a heating system advantageously makes it possible to heat a fluid leaving the condenser circulation circuit to a first temperature, and the fluid thus heated can supply the nozzle.

[0046] Additionally, the manifold can be connected to the second fluid distributor.

[0047] Thus, the fluid collected in the collector can be reinjected into the second fluid distributor, to be used as refrigerant liquid in the condenser circulation circuit.

[0048] In this embodiment, the manifold may be connected to the second fluid distributor by a second connection circuit, the second connection circuit comprising a cooling system configured to cool a fluid circulating in said second connection circuit, a connection pipe connecting the cooling system to the inlet of the refrigerant circulation circuit and a connection pipe connecting said cooling system to the manifold.

[0049] Such a cooling system advantageously makes it possible to cool the part of the unpurified fluid distributed in the form of drops by the nozzle and which has not passed through the membrane in the form of vapor, to use it as a refrigerant liquid.

[0050] As mentioned above, in certain embodiments, the refrigerant circulation circuit and the second space belong to the same closed fluid circuit.

[0051] In one or more alternative embodiments, the refrigerant circulation circuit and the second space belong to two independent fluid circuits.

[0052] In other words, according to these embodiments, there is no exchange of fluid between the second space and the refrigerant circulation circuit. It is therefore not necessarily the same fluid which circulates in the condenser and which is distributed by the nozzle.

[0053] In one or more embodiments, the device may further include a gutter for collecting condensate formed on the wall of the condenser.

[0054] By "gutter" is meant any element allowing the collection of the condensate (here, purified liquid) formed on the wall of the condenser. For example, the gutter can be a channel attached to the wall of the condenser (as in the example shown in Figure 1) and having a certain slope to convey the condensate to a collector of purified liquid. The gutter can also be one or more raised patterns on the wall of the condenser having the same function as the previous example.

[0055] The gutter allows on the one hand to recover the condensate (the purified liquid), and on the other hand to prevent the condensate from coming into contact with the collector, which contains the part of the fluid distributed by the nozzle which has not evaporated and has not passed through the membrane (and which is therefore a fluid even less pure than that distributed by the nozzle). Thus, the gutter allows to collect the condensate without it having come into contact with unpurified fluid, and to convey it into a circuit or into a purified water tank.

[0056] Another aspect of the invention relates to a method for purifying a fluid in the liquid phase using a device described above, comprising: dispensing, through the nozzle, the fluid in the form of drops, the fluid dispensed in the form of drops being at a first temperature; supplying the circulation circuit of the condenser with the refrigerant fluid at a second temperature, the second temperature being strictly lower than the first temperature; and collecting purified fluid in the liquid phase resulting from condensation of a purified fluid in the gaseous phase along the wall of the condenser, said purified fluid in the gaseous phase resulting from passage of a gaseous portion of the fluid dispensed in the form of drops through the membrane.

[0057] In one or more embodiments, the fluid dispensed in drop form is water loaded with salts, and wherein the purified fluid in the liquid phase is pure water.

[0058] In one or more embodiments, the fluid is dispensed in the form of drops by the nozzle in a first direction, and in which the refrigerant circulates in the circulation circuit of the condenser in a second direction opposite to the first direction.

[0059] According to these embodiments, the refrigerant fluid and the fluid distributed in the form of drops by the nozzle circulate in opposite directions, which makes it possible to increase the efficiency of heat exchanges.

[0060] In one or more embodiments, the method further comprises: collecting a portion of the fluid dispensed in the form of drops by the nozzle and circulating in an area delimited by the membrane and comprising the nozzle; cooling said portion of the collected fluid to the second temperature;

[0061] in which the cooled portion of the fluid is used to supply, at least partially, the circulation circuit of the condenser.

[0062] According to these embodiments, the remaining portion of the unpurified liquid dispensed in drop form which has not passed through the membrane in vapor form is recovered to be cooled and reinjected as a refrigerant liquid.

[0063] In addition, the method may comprise: heating the refrigerant fluid at the outlet of the condenser circulation circuit to the first temperature;

[0064] in which the heated refrigerant fluid is used, at least partially, as the fluid to be dispensed in the form of drops through the nozzle.

[0065] In this case, the refrigerant liquid, after passing through the condenser, is heated to feed the nozzle.

[0066] These additional steps advantageously allow the implementation of a closed circuit, in which the fluid is reused, sometimes as a hot liquid supplying the nozzle, sometimes as a refrigerant liquid. As detailed below, the refrigerant liquid heats up as it passes through the condenser, while the The unevaporated portion of the fluid dispensed in the form of drops by the nozzle cools between the time it is dispensed in the form of drops and the time it is collected. Thus, the fluid to be heated has already been partially heated, which limits the energy consumption required to heat the fluid leaving the condenser to the first temperature. In other words, the heat of condensation is advantageously used to limit the energy requirements for operating the device. BRIEF DESCRIPTION OF THE FIGURES

[0067] Other features and advantages of the invention will become apparent upon reading the description, which can be read in conjunction with the figures. These figures are presented for information purposes only and in no way limit the invention.

[0068] [Fig. 1] Figure 1 represents an example device for purifying a fluid in liquid phase, according to an embodiment of the invention. DETAILED DESCRIPTION

[0069] In the following, water is used as an example of a fluid to describe the phenomena, but it is understood that the invention applies to any fluid

[0070] [Fig. 1] Figure 1 represents an example device for purifying a fluid in liquid phase, according to an embodiment of the invention.

[0071] The device of Figure 1 comprises a plurality of semi-permeable membranes 5, i.e. permeable to the fluid in the gas phase, but impermeable to the fluid in the liquid phase. More precisely, the membranes 5 are impermeable to the fluid in the liquid phase, when the latter is, for example, projected against the membranes 5 in the form of drops, the aim being that, in the context of the invention, only gaseous particles of the liquid can pass through the membranes 5. The device also comprises a plurality of condensers (or cold traps) 9. By "condenser" is meant a device configured to condense (or liquefy) vapor. For example, each condenser may be a planar condenser comprising two walls 9a, 9b between which is located a circuit for circulating a refrigerant fluid. The walls 9a, 9b of the condenser 9 are advantageously impermeable to fluids (in both the liquid and gas phases).

[0072] The membranes 5 do not allow drops of liquid distributed by the nozzles 3 to pass through. For example, the membranes 5 may be impermeable to drops of liquid. The membranes 5 may be, for example, membranes made of one or more of the following materials: Teflon or PTFE, Polyvinyl Diene Fluoride or PVDF, Polypropylene or PP and Polyethylene or PE. The pore thickness of the membranes 5 may be determined by routine testing by a person skilled in the art, and in particular pore sizes ranging from 60 micrometers to 60 nanometers may be used. In some embodiments, the membranes 5 may be composed of a fabric coated with a treatment to make it waterproof.

[0073] The material used to make a wall of a condenser or cold trap can be a metal or a heat-conducting material. Stainless steel, for example, or plastic can be used, especially if the cold liquid circulating in the condenser is salt water or corrosive water.

[0074] Referring again to Figure 1, pairs of membranes 5 and condensers 9 are arranged alternately, so that exactly two membranes 5 are arranged between two condensers 9.

[0075] Two membranes 5 arranged between two consecutive condensers 9 delimit a space 4 overhung by a nozzle 3 configured to distribute a fluid in liquid phase in the form of drops or droplets. This space constitutes a “first fluidic channel” 4 in which the fluid distributed by the nozzle 3 circulates. By “fluidic channel” is meant a volume in which a fluid can flow or circulate, in liquid or gaseous phase. A fluidic channel can advantageously be delimited by two separators (for example membranes 5 and / or condenser walls 9), which makes it possible to maximize the heat exchange surfaces or the exchange of matter, as for the passage of steam.

[0076] The space 13 between a condenser 9 and the membrane 3 closest to the condenser 9 is called the “second fluid channel” 13. Each second fluid channel 13 may comprise a gutter 11 or any other means for recovering a liquid formed by condensation on the condenser 9. The gutter 11 may be connected to a purified or pure water collector 12.

[0077] Thus, in Figure 1, the channel 4 and the condenser 9 are separated by a small tank or gutter 11 for collecting drops of water in liquid water from the surface of the wall 9a, 9b of the condenser 9. The first channel 4, the nozzle 3, the gutter 1 1 and the condenser 9 form a periodic pattern repeated in Figure 1, between a hot water distributor 2 and a hot water collector 6 connected via the channel 4 containing the nozzle 3 and between a cold water distributor 8 and a cold water collector 10 connected via the condenser 9.

[0078] It appears from the remainder of the description that the invention can be implemented when the device comprises a nozzle 3, a membrane 5 and a condenser 9, the membrane 5 being located between the nozzle 3 and the condenser 9. Thus, the invention is not limited to a plurality of nozzles 3, condensers 9 and membranes 5. When the device comprises a plurality of these elements, the volume of purified liquid collected is greater, since purified liquid can be collected in parallel in several channels each bordered by a membrane 5 and a wall 9a, 9b of condenser 9, for example via several gutters such as gutter 11.

[0079] Figure 1 thus shows a hot water supply 1 connected, in the fluidic direction, via a hot water distributor 2 to the nozzle 3 arranged internally to the membrane of the channel 4 as well as a hot water collector 6 extending the channel 4.

[0080] Figure 1 also shows a cold water supply 7 connected to the condenser 9 via a cold water distributor 8 which is fluidically connected to a cold water collector 10 via the condenser 9.

[0081] In Figure 1, the membranes 5 and the walls 9a, 9b of the condensers 9 are vertical and parallel surfaces. It is understood that the degree of parallelism of these elements may, without departing from the teaching of the present application, be imperfect. In particular, it is especially important that a fluid in the vapor phase can reach a wall of the condenser 9 via the channel 4. The verticality of the membranes 5 and the walls 9a, 9b of the condensers 9 are therefore to be understood in the present application as a characteristic making it possible to maximize the conversion of vapor into liquid, between the interior of the membrane of the first channel 4 and the surface of the wall 9a, 9b of the condenser 9, while facilitating the collection of condensates by the gutter and minimizing the size of the entire device.From this point of view, the “vertical” characteristic, in the geometric sense, can be understood within the meaning of the present invention and in all its embodiments as forming an angle for example between 70° and 110° relative to the ground.

[0082] According to the invention, an unpurified hot liquid (the liquid may be a mixture, for example, of water and minerals or water and salt or solutes) is introduced by a feed 1, then distributed by a hot liquid distributor 2 to nozzles 3 which disperse it vertically in the form of drops inside the channels 4. For example, the unpurified hot liquid may be water from a water reserve, for example a sea or a lake or a wastewater reserve, possibly heated to a first temperature called "hot".

[0083] A second liquid, called refrigerant liquid, which is colder than the hot liquid, is introduced by a supply 7, then distributed by a cold liquid distributor 8 which distributes it in the condensers 9 arranged in parallel in Figure 1.

[0084] By "hot liquid" is meant a liquid having a temperature higher than the maximum temperature of the refrigerant circulating in the condenser 9. For example, the difference between the temperature of the hot liquid (when it is dispensed in the form of drops by the nozzles 3) and the maximum temperature of the refrigerant circulating in the condenser 9 may be greater than 30°C. For example, the hot liquid may be dispensed in the form of drops at a temperature between 60°C and 90°C, and the refrigerant may have a temperature between 10°C and 30°C. Of course, the preceding temperatures are provided as examples and other temperatures or temperature differences may be used.

[0085] After being distributed in the form of drops by the nozzle 3, the unpurified and hot liquid circulates in the channel 4 delimited by two membranes 5, and a portion of this unpurified and hot liquid passes, in the form of purified fluid vapor, through the membranes 5. For example, if the unpurified and hot liquid is salt water, a portion of this liquid passes in the form of pure water vapor and passes through the membranes 5. There then remains in the channel 4 delimited by the two membranes 5 liquid that is even less purified (i.e. more concentrated for at least one of its components, for example water even more loaded with salt, since a portion of pure water has evaporated) and colder than at the outlet of the nozzle 3. This liquid that is saltier and less hot than at the nozzle outlet can then be recovered in a collector 6.

[0086] Indeed, the role of the membranes 5 or the membrane 5 is to prevent the liquid distributed in the form of drops in the channel 4 from passing partially or totally into the zone 13 delimited by a condenser 9 and a membrane 5. Only vapor from the liquid can pass through, thus avoiding any contact between the hot liquid present in the channel 4 and the condensates of the vapor formed in the zone 13 on the wall of the condenser 9. When a temperature difference is created between the two sides of the membrane 5, a difference in partial vapor pressure appears, constituting the engine of the process. This causes the evaporation of liquid from the surface of the liquid on the hot side, generating vapor that passes through the membrane 5 and condenses on the colder side where the condenser 9 is located.

[0087] The space between a condenser 9 and a membrane 5 forms a channel 13 in which the vapor of the hot liquid coming from the nozzle 3 and having passed through the membrane 5 diffuses. The role of the condensers 9 is to condense this vapor on one of its walls 9a, 9b to form purified liquid. This purified liquid is colder than the vapor from which it comes, while conversely, the refrigerant liquid heats up on contact - via the wall 9a, 9b of the condenser 9 - with the hotter vapor.

[0088] The refrigerant liquid can be collected at the outlet of the circulation circuit of the condenser 9 in a cold liquid collector 10, at a temperature higher than that which it had at the inlet of the circulation circuit of the condenser 9.

[0089] The condensate (purified water for example) slides along the wall of the condenser 9 and can be collected in the gutter 11 placed for example on the wall (several gutters in the direction of the height of the condenser 9 can also be provided). The condensate can then be transported laterally to be collected in a pure water tank or collector 12.

[0090] According to alternative methods, the gutter or gutters 11 can either be attached to the condensers by mechanically fixing the material making up this gutter or these gutters, or delimited by the external shape of the condenser or condensers by molding, that is to say delimited by the wall of a condenser, i.e. by the shape of its external surface on which the condensation is obtained.

[0091] It is noted that in the example of Figure 1, the elements of the device are arranged in the following order, in a direction parallel to the membranes 5 and oriented from the cold water collector 10 and the refrigerant liquid distributor 8: the cold water collector 10, the hot water distributor 2, the hot water collector 6 and the refrigerant distributor 8. Such an arrangement allows circulation of the liquids in the channel 4 and the refrigerant circulation circuit in the condenser 9 in the opposite direction or countercurrently. Such countercurrent circulation advantageously allows a particularly efficient exchange of heat between the hot drops produced by the nozzle 3 and the cold liquid via the membrane 5 and the wall 9a, 9b of the condenser 9.

[0092] Other configurations are possible, and according to an alternative embodiment of the invention, the elements of the device can be arranged in the following order, in the direction parallel to the membranes 5 and oriented from the cold water collector 10 and the refrigerant distributor 8: the cold water collector 10, the hot water collector 6, the hot water distributor 2 and the refrigerant distributor 8. In this case, the circulation of the liquids in the channel 4 and the refrigerant circulation circuit in the condenser 9 is carried out in the same direction, and the invention is still functional, even if the heat exchanges are less efficient than in the embodiments where the circulation of the liquids is done in the opposite direction.

[0093] As mentioned above, the invention can be implemented by means of a supply 1 of hot water or hot fluid at a first temperature, distributed in the form of drops by a nozzle 3 and creating a vapor of the (purified) fluid and drops of the fluid (even less pure than the hot fluid distributed by the nozzle 3), the vapor of the fluid passing through the membrane 5 permeable to vapor and impermeable to drops, to reach a wall 9a, 9b impermeable to the fluid, the wall 9a, 9b being supplied with a refrigerant fluid via a cold water supply 7, the refrigerant fluid being injected between the walls of the condenser 9 at a second temperature lower than the first temperature. Thus, condensation of the fluid occurs in drops of purified water on a surface of the wall 9a, 9b, in contact with which flows cold water or a purified cold fluid at a temperature lower than the first temperature.

[0094] Several methods of implementing hot and cold supplies are possible.

[0095] In a first embodiment, the hot fluid and the cold fluid are not reused and are both lost: there is then an open-circuit hot fluid supply and an open-circuit cold fluid supply, independent of the hot fluid supply. In other words, once the refrigerant liquid has passed through the condenser 9, it is purged from the device. Similarly, the part of the hot liquid that has not evaporated (part of the liquid that arrives at the bottom of the channel 4, which is less hot and saltier than the liquid distributed in the form of drops by the nozzle 3) is purged from the device, for example discharged to a wastewater circuit. A new refrigerant fluid is injected into the condenser 9 via the cold water supply 7 and a new hot liquid feeds the nozzle 3 via the hot liquid distributor 2.

[0096] In a second embodiment, the hot fluid is reused to be purified again. In other words, the part of the hot and salty liquid distributed in the form of drops by the nozzle 3 which has not passed through the membrane 5 in the form of vapor is collected at the bottom of the channel 4. As this remaining liquid has cooled during its passage in the channel 4, it is possible to heat it up to the first temperature using a heating system and then reinject it into the hot liquid distributor 2, to be distributed in the form of drops by the nozzle 3. For example, the liquid collector 6 can be connected to the inlet of the heating system, for example via a connecting pipe, and the heating system can be connected at its outlet to the hot liquid distributor 2, for example via a connecting pipe.In this case, the supply of hot fluid is said to be in a "closed circuit", even if this term does not exclude that additional liquid can be injected into the circuit via the hot water supply 1. In this embodiment, after a few passes through the device, the remaining liquid is highly salty, which requires it to be discarded after a certain number of cycles. Alternatively, it is possible to reinject, either after each pass or after a predefined number of passes through the device, less salty liquid (for example sea water heated to the first temperature). Thus, in this embodiment, the hot liquid distributor 2 is advantageously connected, via the heating system, to a source of unpurified liquid, to regularly dilute the hot liquid distributed in the form of drops by the nozzles 3.In this second embodiment, the refrigerant fluid can be discarded as in the first embodiment, or reused as in the. third embodiment described below. However, in this embodiment, the hot fluid and refrigerant fluid supplies are independent.

[0097] In a third embodiment compatible with the second embodiment, the refrigerant fluid leaving the condenser 9 is reinjected into an inlet thereof. In other words, the cold liquid collector 10 is connected to the cold liquid distributor 8 so that the refrigerant fluid leaving the condenser 9 and arriving in the cold liquid collector 10 is reinjected into the inlet of the condenser 9 via the cold liquid distributor 8. When the refrigerant fluid circulates from the inlet of the condenser (connected to the cold liquid distributor 8) to the outlet of the condenser 9 (to reach the cold liquid collector 10), it heats up due to the contact between the hot liquid vapor and the wall 9a, 9b of the condenser. Also, the refrigerant fluid leaving the condenser 9 is advantageously cooled in a cooling system before being reinjected into the condenser 9.For example, the cold liquid collector 10 can be connected, via a connecting pipe, to an inlet of the cooling system, and an outlet of the cooling system can be connected, via another connecting pipe, to the cold liquid distributor. According to this embodiment, the supply of refrigerant fluid is in a “closed circuit” (and it is not necessary to provide a supply of additional refrigerant fluid, since the latter does not undergo a priori any transformation or loss). In this third embodiment, the hot fluid can be discarded as in the first embodiment, or reused as in the second embodiment. However, in this third embodiment, the supplies of hot fluid and refrigerant fluid are always independent.

[0098] In a fourth embodiment, the hot fluid and refrigerant fluid supplies are not independent: the remaining portion of the hot liquid is cooled to the second temperature to be used as refrigerant liquid, then reheated at the outlet of the condenser 9 to the first temperature to be distributed in the form of drops by the nozzles 3, and so on. It is noted that at the outlet of the condenser 9, the refrigerant liquid has heated up, which reduces the amount of energy to be supplied to bring it to the first temperature. Also, at the outlet of the channel 4, the remaining portion of hot fluid has cooled down, which also reduces the amount of energy to be supplied to bring it to the second temperature. To implement this fourth embodiment, it is possible for example to attach the collector of hot liquid 6 to the inlet of the cooling system and to connect the outlet of the cooling system to the cold liquid distributor 8 to feed the condenser 9. The cold liquid collector 10 can be connected to the inlet of the heating system, and the outlet of the heating system can be connected to the hot liquid distributor 2 to be distributed in the form of drops by the nozzles 3. In this fourth embodiment, there is a single closed-circuit fluid supply, traversed by the hot fluid and then by the same cooled fluid (possibly more salty). Here again, even if the term "closed circuit" does not exclude that additional liquid can be injected into the fluid circulation circuit.Indeed, after several passages through the device, the remaining liquid may be highly salty, and it is possible to reinject, regularly or when it is detected that the salt concentration of the circulating liquid exceeds a threshold value, less salty liquid (for example sea water) into the fluid circulation circuit. For example, the cooling system and / or the heating system may comprise an inlet for receiving less salty liquid. Alternatively, the less salty liquid may be added upstream of the cooling system or the heating system. Thus, in this fourth embodiment, the liquid circulation circuit may advantageously be connected to a source of unpurified liquid, to regularly dilute the circulating liquid and supply both the condensers 9 and the nozzles 3.

[0099] This fourth embodiment makes it possible to improve the thermodynamic efficiency of the liquid purification process: in fact, a latent heat exchange takes place between the vapor of the fluid used and the drops of this fluid distributed in the form of recycled drops in the undivided liquid phase, in contact with the wall. This characteristic improves condensation and simultaneously heats the recycled liquid by reducing the power required to heat this liquid to the distribution temperature by the nozzle 3. A saving of 50% in heating power can thus be observed compared to the other embodiments, this figure being able to vary depending on the sizing.

[0100] In this fourth embodiment, it is possible to use a single pump to suck the liquid from the drops distributed in the form of heated drops and the liquid from a hot water source to carry out the initial hot water supply to the nozzle of the closed fluid circuit above and obtain a generator of purified water or fluid in the liquid state purified by means of the device of the present application. In other words, in this embodiment, the device comprises an initial supply of hot water, distributed in the form of drops by a nozzle and separated by a membrane permeable to water vapor, impermeable to water drops distributed in the form of drops and non-absorbent for water, from a fluid-impermeable condenser, in contact with cold water on one side and on the other side with the water vapor collected after condensation, in drops of purified water resulting from the condensation of the water vapor transported between the nozzle and the condenser via the membrane. The purified liquid can be collected thanks to one or more gutters placed on the surface of the condenser.

[0101] With reference to Figure 1, it is possible to establish a first fluid connection between the hot water collector 6 and the cold water supply 7 and then to establish a second fluid connection between the cold water collector 10 and the hot water supply 1 of the nozzle 3 to produce the closed fluid circuit of the fourth embodiment. In addition, a cooling means, in particular via a heat exchanger, can be inserted on the first connection. Finally, a heating means such as a heat exchanger with a hot source can be inserted on the second connection and a pump can also be inserted in series on this second connection to obtain a complete device for producing purified fluid and in particular purified water.

[0102] In all embodiments, the heating system may comprise, for example, an electrical resistor or may be a system for bringing the fluid into thermal contact with a heat source, i.e. at a higher temperature than the fluid. Particularly advantageously, the heating system may use waste heat from an industrial process.

[0103] The cooling system may be a system allowing the fluid to be put into thermal contact with a cold source, i.e. at a lower temperature than the fluid.

[0104] In one or more embodiments, a compression of a liquid can be carried out after a distribution in the form of drops by nozzle by collecting or gathering the liquid in “divided” form (i.e. in the form of drops) present at the outlet of the channel 4 to make it return to a “non-divided” liquid form. divided >> (i.e. in the form of a gathered liquid and not in the form of drops), then sucking up this liquid with a pump and compressing the liquid form using the pump.

[0105] A sizing of the characteristics of the device according to one embodiment, to obtain a purified water condensate of 30 tonnes per day in an installation using sea water, is detailed below as an example.

[0106] A reserve of cold, salty seawater, for example taken from an ocean, can be used as a cold source and a means of dilution, as well as a source of heat, for example obtained by solar heating or by recovering energy lost in an engine.

[0107] Cold, salty seawater can be introduced into a closed fluid circuit and circulated by means of a pump.

[0108] The seawater can, in this closed fluid circuit, be preheated by the condensation of the water vapor by passing through the condenser 9, in a direction opposite to that of the hot drops (countercurrent configuration), then reheated by the heat source by means of a first exchanger with separate fluids. It can then pass through a nozzle immersed in an atmosphere, then be distributed in the form of drops (for example, sprayed) in the atmosphere by losing water vapor, to be collected, in concentrated salt form, in a tank. The concentrated salt water can be pumped from the tank, then cooled by the reserve of cold seawater in a second exchanger with separate fluids, and finally be diluted by water from the reserve of cold seawater in a mixer.In the atmosphere, a membrane 5 permeable to water vapor and impermeable to liquid water can separate the nozzle 3 and the condenser 9, and allow condensation to be obtained with separate fluids, between the liquid emitted by the nozzle 3 and the condensate. The condensate and the liquid circulating in the condenser 9, made of a fluid-impermeable material, are separated by the material of the condenser 9.

[0109] In this way, a closed circuit of seawater is obtained capable of producing, on the external wall of the condenser, a condensate of the water vapor taken from the drops and having migrated via the membrane. This produces purified water without contact with the seawater, neither in its form distributed by the nozzle, nor in its form transported inside the condenser, nor in its form contained in the hot water reserve.

[0110] With material being taken from the circuit in the form of water vapor, the mixer allows the seawater, concentrated by evaporation, to be diluted with seawater from the cold water reserve. The seawater from the reserve plays a primary role here as a material reservoir, namely a seawater reservoir with a constant salt concentration. The mixer can be connected to the circuit intermittently or continuously, depending on a desirable salinity range for the seawater circulating in the closed circuit.

[0111] Furthermore, advantageously, the seawater reserve can also be used to additionally cool the concentrated water by evaporation leaving the hot water collector, to bring it to a temperature close to that of the cold, salty seawater reserve, here playing a second role as a thermal reservoir.

[0112] The resulting device is particularly favorable for heat recovery and condensation. Tests were conducted on such a device with two condenser and membrane heights (the condensers and membranes having the same heights): 3 m for the first test and 2 m for the second test. These dimensions make it possible to obtain a heat expenditure of 300 (first case) to 450 (second case) kWh per m 3 These figures can be compared to a heat expenditure for a device without this heat recovery, which is of the order of 700 kWh per m 3 of condensate. This therefore represents an energy gain of 57% in the first test and 35% in the second test.

[0113] Given this energy performance, 30 tonnes of purified water can be obtained per day with a flow rate of 6.55 kg / s in the nozzle, a mixer inlet flow rate distributed as 5.51 kg / s for the water collected via the drops emitted by the nozzle and 1.04 kg / s for the water taken from the cold seawater reserve.

[0114] The cold seawater flow rate for supplementary cooling by sensible heat loss can be adjusted to obtain a temperature 3 K higher than the cold reserve temperature in order to obtain at the mixer outlet and nozzle inlet, a temperature 2.5 K higher than the temperature of the cold seawater reserve. Similarly, the temperature of the hot source can be 58 K higher than that of the cold water reserve, in permanent mode of production of purified water.

[0115] For these performances, the temperature of the cold seawater reserve can be 305 K and the temperature of the warm seawater reserve 363 K.

[0116] The person skilled in the art will be able, by simple routine tests, to adapt the dimensions of the above embodiment to obtain different productions of purified water or different energy yields depending on the heat recovered or from available solar energy and the climate, without departing from the teaching of the present application.

[0117] This application extends its teaching to a solvent containing a solute to obtain the purified (or pure) or ultra-purified (or ultra-pure) solvent.

[0118] In all embodiments of the present application, the membrane and the wall of the condenser must not be in mechanical contact, which guarantees optimum purity of the purified fluid. However, if contact points between the membrane and the wall exist, degraded operation of the device and the method according to the invention is obtained. For example, the purification of water initially loaded with minerals at 500 Micro Siemens / cm results, without mechanical contact, in purified water having a conductivity of less than 9 Micro Siemens / cm, whereas the presence of contact points leads to purified water having a conductivity of the order of 50 Micro Siemens / cm.

Claims

CLAIMS

1. Device for purifying a fluid in liquid phase, comprising: - a nozzle (3) for distributing said fluid in the form of drops into an atmosphere; - a wall (9a, 9b) of a condenser (9); and - a membrane (5) permeable to said fluid in the gas phase and impermeable to said fluid distributed in the form of drops in the atmosphere, the membrane (5) being arranged between the nozzle (3) and the wall of the condenser (9); wherein the wall of the condenser (9) and the membrane (5) delimit a first space (13), the membrane (5) separates the first space (13) from a second space (4) comprising the nozzle (3), and wherein the condenser (9) comprises a circulation circuit for a refrigerant fluid, the wall of the condenser (9) separating the circulation circuit for the refrigerant fluid and said first space (13), the wall of the condenser (9) being impermeable to the fluid in the liquid phase and in the gas phase and being configured to condense the fluid in the gas phase passed through the membrane into a liquid phase of purified fluid.

2. Device according to claim 1, in which the membrane (5) comprises a first face facing the first space (13) and a second face facing the second space (4), in which the membrane (5) is configured to operate at equal pressure on its first face and on its second face.

3. A device according to claim 2, wherein said pressure is atmospheric pressure.

4. Device according to one of the preceding claims, in which the membrane (5) and the wall of the condenser (9) extend in substantially vertical planes.

5. Device according to one of the preceding claims, further comprising a first fluid distributor (2) for supplying the nozzle (3) with said fluid in liquid phase and a second fluid distributor (8) for supplying the refrigerant circulation circuit with the refrigerant.

6. Device according to one of the preceding claims, wherein the device comprises a collector (6) configured to collect at least part of the fluid distributed by the nozzle (3) in the form of drops and circulating in the second space (4).

7. Device according to one of the preceding claims, in which the refrigerant circulation circuit, the nozzle (3) and the second space (4) belong to the same fluid circuit.

8. Device according to claim 7 in combination with claim 5, wherein the refrigerant circulation circuit comprises an inlet and an outlet, the device further comprising a first connection circuit between the outlet of the refrigerant circulation circuit and the first fluid distributor (2).

9. Device according to claim 8, wherein the first connection circuit comprises a heating system configured to heat a fluid circulating in said first connection circuit, a connection pipe connecting the outlet of the refrigerant circulation circuit to said heating system and a connection pipe connecting said heating system to the first fluid distributor (2).

10. Device according to claim 9 in combination with claim 6, wherein the manifold (6) is connected to the second fluid distributor (8). [Claim 1 1] Device according to claim 10, wherein the manifold is connected to the second fluid distributor (8) by a second connection circuit, the second connection circuit comprising a cooling system configured to cool a fluid circulating in said second connection circuit, a connection pipe connecting the cooling system to the inlet of the refrigerant circulation circuit and a connection pipe connecting said cooling system to the manifold (6).

12. Device according to one of claims 7 to 11, in which the refrigerant circulation circuit, the nozzle (3) and the second space (4) belong to the same closed fluid circuit. Tl

13. Device according to one of claims 1 to 6, in which the refrigerant circulation circuit and the second space (4) belong to two independent fluid circuits.

14. Device according to one of the preceding claims, further comprising a gutter (11) for collecting condensate formed on the wall of the condenser (9).

15. A method of purifying a fluid in liquid phase using a device according to one of claims 1 to 14, comprising: - distribute, through the nozzle (3), the fluid in the form of drops, the fluid distributed in the form of drops being at a first temperature; - supplying the circulation circuit of the condenser (9) with the refrigerant fluid at a second temperature, the second temperature being strictly lower than the first temperature; and - collecting purified fluid in liquid phase resulting from condensation of a purified fluid in gas phase along the wall of the condenser (9), said purified fluid in gas phase resulting from passage of a gaseous part of the fluid distributed in the form of drops through the membrane (5).

16. A method according to claim 15, wherein the fluid dispensed in the form of drops is water loaded with salts, and wherein the purified fluid in the liquid phase is pure water.

17. Method according to one of claims 15 and 16, in which the fluid is distributed in the form of drops by the nozzle (3) in a first direction, and in which the refrigerant circulates in the circulation circuit of the condenser (9) in a second direction opposite to the first direction.

18. A method according to one of claims 15 to 17, further comprising: - collect a portion of the fluid distributed by the nozzle (3) in the form of drops and circulating in an area delimited by the membrane (5) and comprising the nozzle (3); - cooling said portion of the collected fluid to the second temperature; in which the cooled part of the fluid is used to supply, at least partially, the circulation circuit of the condenser (9).

19. The method of claim 18, further comprising: - heating the refrigerant fluid at the outlet of the circulation circuit of the condenser (9) to the first temperature; in which the heated refrigerant fluid is used, at least partially, as fluid to be distributed in the form of drops by the nozzle (3).

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