WO2010112776A1

WO2010112776A1 - Osmotic evaporation method and device

Info

Publication number: WO2010112776A1
Application number: PCT/FR2010/050618
Authority: WO
Inventors: Fabrice Gascons Viladomat; Magali Arnaud
Original assignee: Ederna
Priority date: 2009-04-02
Filing date: 2010-03-31
Publication date: 2010-10-07
Also published as: FR2943926B1; FR2943926A1

Abstract

The invention relates to an osmotic evaporation process in which: a porous membrane (30), for osmotic transfer of a compound in the gaseous state between first and second faces of this porous membrane (30), is chosen; and at least one osmotic transfer step is carried out in which a liquid feed composition is made to flow in contact with said first main face of the porous membrane (30) and a liquid extraction composition (3) is made to flow in contact with said second main face of the porous membrane (30), characterized in that, after said osmotic transfer step, at least one fluid inlet (13) of the feed circuit (6) is brought into communication with a pressurized gaseous composition source (21), designed to exert pressure, called the gas pressure, in the feed circuit (6), said gas pressure being above atmospheric pressure.

Description

OSMOTIC EVALUATION METHOD AND DEVICE

The invention relates to a method and an osmotic evaporation device. Such a method and such a device are adapted to allow osmotic transfer of at least one gas phase compound between two liquid compositions - particularly two miscible liquid compositions - separated by a porous membrane. Such a method and such a device relate in particular to an osmotic transfer in the gas phase of at least one solute or at least one solvent of one of the liquid compositions. The invention furthermore relates to such a method and such an osmotic evaporation device making it possible to completely recover the compounds of interest from liquid compositions treated by osmotic evaporation, in particular the compounds with high added value of said liquid compositions. In addition, the invention relates to such a method and such an osmotic evaporation device of reduced energy consumption, and allowing the recycling of the extraction solutions used. The invention therefore relates to a method and an osmotic evaporation device that are environmentally friendly.

Such a method and such an osmotic evaporation device make it possible in particular to increase the concentration of a solute of a liquid composition by extracting at least a quantity of at least one solvent from the liquid composition. However, it is also possible to perform such osmotic evaporation in order to extract a volatile solute from a liquid composition. In particular, such an osmotic evaporation is adapted to displace the thermodynamic equilibrium of a chemical reaction by extracting at least one solute or volatile solvent produced during said reaction and to improve its efficiency.

No. 6,569,341 discloses a method for concentrating a liquid solution, in particular a fruit juice, in which a contactor of the liquid / liquid contactor type is used formed of a membrane structure comprising a non-porous, gas-permeable face in contact with another face microporous, said nonporous face being in contact with the feed solution and said microporous face being in contact with an extraction solution. Such a membrane structure preserves the microporous face of the contact with the feed solution and prevents the feed solution from modifying the wettability of said microporous face. No. 6,569,341 depicts FIG. 2 an osmotic evaporation device comprising an osmotic evaporation membrane module forming an interface between an extraction loop and a feed loop.

Such a device does not make it possible to treat by osmotic evaporation solutions of low volume of compounds with high added value, and to recover substantially all of the concentrated solution contained in the feed circuit and without subsequent dilution thereof.

This device also poses problems of practical realization, in particular it does not recycle the extraction solution, which must be renewed. It is further limited in its applications to the case of the concentration of fruit juice on an industrial scale.

The aim of the invention is to overcome the disadvantages mentioned above by proposing an environmentally friendly osmotic evaporation method and device adapted to be implemented on an industrial scale, but also on an installation scale. preindustrial pilot.

The invention furthermore aims at such a method and such an osmotic evaporation device adapted to the constraints of a laboratory - in particular a research and development laboratory - for the treatment of low volume solutions, in particular of the order of a few liters, for which solute recovery efficiency of the order of 100% is required.

The aim of the invention is to propose such an osmotic evaporation method that is applicable in particular for the preparation of solutions containing one or more compounds to be concentrated, in particular containing biologically active principles, which are valuable and / or have a high added value, in particular principles therapeutically active, and whose recovery must be quantitative. In this context, the invention also aims at providing such a process and such an osmotic evaporation device adapted for the successive treatment of a plurality of solutions to be treated, while avoiding the cross-contamination of these solutions, without causing loss. said solutions treated and without subsequent dilution of these treated solutions.

Furthermore, it should be noted that the invention aims to provide such a method and such an osmotic evaporation device of improved efficiency, and which are economical and environmentally friendly.

The invention also aims at providing such an osmotic evaporation device which is compact, of reduced size, weight and dead volume, and can be moved to a suitable site of use.

The invention also aims at providing such a device capable of being used for the treatment of a solution in a substantially aseptic environment, particularly in a microbiologically controlled environment, in particular in a microbiological safety station.

The invention also aims at providing an osmotic evaporation method and device adapted for the treatment of solutions, at ambient temperature, and preserving the thermolabile components of any degradation.

The invention also aims at providing a method and an osmotic evaporation device for the treatment of a solution at a pressure of the order of atmospheric pressure.

In addition, the invention aims to provide an osmotic evaporation process operating at room temperature and preserving the device risks of scaling or corrosion. The invention also aims to provide such a method and such a device for the treatment of a solution by osmotic evaporation allowing the concentration of solutes prior to a subsequent lyophilization treatment.

The invention also aims to provide such a method and such an osmotic evaporation device to advantageously recycle the diluted extraction solution. The invention also aims to provide such a device that is ergonomic, easy to use, high transfer efficiency, which is simple in its implementation and adapted to provide reliable and reproducible results. The invention also aims at providing such a method and such a device for osmotic evaporation suitable for applications for example in the field of fine chemistry, pharmacy, food industry, biotechnology, in which arises the problem of the extraction, the concentration and the quantitative recovery of a synthetic or natural substance, in particular of a thermolabile substance, of high added value.

In particular, the thermolabile substances concerned by such an osmotic evaporation process are, for example, proteins, peptides, amino acids, vitamins, polyphenols, odor molecules, volatile organic compounds or natural dyes. The invention also aims to achieve all these objectives at lower cost, by proposing a low cost device, made from usual and inexpensive means.

The invention also aims at providing such a method and such a device that are compatible with the safety constraints for the user and the environment, and having improved properties in terms of reliability, reproducibility of osmotic evaporation.

The invention further aims to provide such a method and such a device that preserve the work habits of staff, which are easy to use, and which imply for their implementation that little manipulation. To this end, the invention relates to an osmotic evaporation process in which:

a porous membrane adapted to allow an osmosis transfer of at least one compound in the gaseous state between a first main face and a second main face of this porous membrane is chosen, at least one osmotic transfer step is carried out in which: a liquid feed composition is circulated in a first circuit, said feed circuit, in contact with said first main face of the porous membrane, said feed circuit comprising a liquid composition feed tank; 'food ; circulating a liquid extraction composition in a second circuit, said extraction circuit, in contact with said second main face of the porous membrane, said extraction liquid composition exerting a pressure, called extraction pressure, on said second main face having a value less than the Laplace pressure of said porous membrane and said liquid extraction composition,

characterized in that after said osmotic transfer step, a purge step of the supply circuit is carried out in which at least one fluid inlet of the supply circuit is placed in communication with a source of gaseous composition under pressure, immiscible with the liquid feed composition, and adapted to exert a pressure, called a gas pressure, in said feed circuit by a value greater than the value of the atmospheric pressure and so as to displace the liquid feed composition of the supply circuit in the supply tank.

In all the following:

the expression "osmotic evaporation" designates a step of a process in which at least one compound (solvent or solute) of a first liquid composition passes from the liquid state to the gaseous state and is transferred by osmosis to the a gaseous state to a second liquid composition in which it is absorbed;

the Laplace pressure (P) of the pair formed by the porous membrane of a membrane contactor and by a liquid extraction composition, given by equation (1), is the maximum pressure value capable of being exerted on one of the two main faces of the porous membrane of said membrane contactor by a liquid extraction composition in contact with said main face, without said liquid extraction composition passing through the pores of the membrane contactor; P = - 2 σ cosθ / r (1), in which: P is the Laplace pressure (Pa), σ is the surface tension between the liquid extraction composition and the gas composition (N / m), cosθ is the cosine of the contact angle formed between the liquid extraction composition and the constituent material of the porous membrane, r is the measurement of the pore radius, (m).

Preferably, the gaseous composition under pressure may be a gas previously compressed and delivered into the feed circuit from a pressurized gas tank. The gaseous composition may also be air pressurized by means of a compressor, especially from a compressed air distribution network.

It is also possible to deliver into the feed circuit a quantity of gaseous composition under pressure from a reserve of a gas or a liquefied gaseous composition (e) and which is relaxed before it is introduced. in the supply circuit.

Preferably, the gaseous composition introduced into the feed circuit is at a temperature of the order of ambient temperature.

However, it is possible to introduce into the feed circuit, a gaseous composition previously heated to a temperature above room temperature.

Advantageously, the liquid feed composition and / or the gaseous composition are circulated in the feed circuit so that the flow of the liquid feed composition and / or gaseous composition is substantially tangential to the first main face of the feed. the porous membrane. It is possible to circulate the liquid extraction composition in the extraction circuit so that the flow of the liquid extraction composition is substantially tangential to the second main face of the porous membrane. Thus, the flow direction of the liquid feed composition and the flow direction of the liquid extraction composition are substantially perpendicular to the main direction of the gaseous compound flow transferred between the first and second major faces of the the porous membrane.

Advantageously, in the case of a membrane contactor formed of hollow fibers, it is possible that the liquid feed composition flows inside the fibers substantially tangentially to the first main face of the porous membrane and that the liquid composition extraction pipe flows outside the hollow fibers in a shell according to a flow direction substantially perpendicular to the second main face of the porous membrane.

Advantageously and according to the invention, the gaseous composition is chosen from the group consisting of atmospheric air, nitrogen, rare or inert gases - in particular argon and helium - and one of their mixtures. In particular, the gaseous composition is selected from the group consisting of immiscible gases with the liquid feed composition.

Advantageously and according to the invention, the porous membrane is selected from the group consisting of porous hydrophobic hollow fibers. A membrane contactor is preferably chosen formed of a porous hydrophobic hollow fiber bundle in which the contact surface of the hollow fibers with the liquid feed composition and with the liquid extraction composition is increased relative to the total volume of the membrane contactor. .

Such a membrane contactor has a first compartment, said supply compartment, in contact with the first main face of the porous membrane. Such a supply compartment comprises a fluid inlet and a fluid outlet adapted for the flow of the liquid feed composition and / or gas composition is made, in the feed compartment, tangentially to the first main face of the porous membrane.

Such a membrane contactor further has a second compartment, said extraction compartment, in contact with the second main face of the porous membrane. Such extraction compartment comprises a fluid inlet and a fluid outlet adapted so that the flow of the liquid extraction composition is made, in the extraction compartment, tangentially to the second main face of the porous membrane. Advantageously and according to the invention, the liquid feed composition and the countercurrent extraction liquid composition are circulated in contact respectively with the first and second main faces of the porous membrane.

Advantageously and according to the invention, the supply circuit comprising a supply reservoir of liquid feed composition, it performs a purge step of the supply circuit in which said fluid inlet of the supply circuit is communicating with the pressurized gaseous composition source so as to move the liquid feed composition of the feed circuit into the feed tank. This purge operation of the feed circuit makes it possible to recover all of the concentrated feed liquid composition, this operation being carried out without dilution of said liquid feed composition, or introduction of the liquid feed composition into the pores of the feed. the porous membrane. Advantageously and according to the invention, a first portion of the supply circuit is purged sequentially into the supply tank, and then a second complementary portion of the supply circuit is purged into the supply tank. Thus, the total purge of the supply circuit is carried out in two successive steps. Advantageously and according to the invention, during the step of purge, it directs the flow of said gas composition alternately in the portion of the feed circuit comprising the porous membrane and in the portion of the feed circuit not comprising the porous membrane.

Advantageously and according to the invention, the gaseous composition under pressure being immiscible with the liquid feed composition, the quantity of liquid feed composition of the portion of the feed circuit comprising the membrane contactor is first displaced to the feed tank, and then moves the amount of liquid feed composition of the portion of the feed circuit not comprising the membrane contactor to the feed tank. In such a process according to the invention, substantially all of the liquid feed composition of the feed circuit is recovered in the feed tank.

Advantageously and according to the invention, after the osmotic transfer step, at the end of which a concentrated liquid feed solution and a diluted liquid extraction composition are formed, a step of recycling the liquid composition of the liquid is carried out. diluted extraction, wherein: the diluted liquid extraction composition is maintained at a predetermined temperature, wherein circulation of the diluted liquid extraction composition is maintained in the extraction circuit, so that the extraction pressure is lower than the Laplace pressure of said porous membrane, where the fluid inlet of the supply circuit is brought into communication with the gas composition source, said gas composition being capable of loading with a compound of the liquid composition extraction in the gaseous state.

The inventors have observed that the introduction of a gaseous composition under pressure makes it possible to carry out an osmotic transfer of water vapor from the liquid extraction solution to the gaseous composition which is charged with steam. In doing so, the inventors have observed that it is possible to recycle by concentration a diluted liquid extraction composition during a prior osmotic evaporation operation.

It is possible to perform such a recycling operation of the liquid extraction composition which is faster by increasing the gas flow rate and the temperature of said extraction solution. However, it is also possible to carry out this recycling operation so that it continues for a longer period of time - especially during the night. We will then choose a flow rate of the gas composition and a temperature of the extraction solution adapted to the specifications of the membrane contactor. It is also possible to subject, during the recycling step, the gaseous composition charged with water vapor to a condensation treatment of water vapor under reduced pressure. In particular, this condensation step is carried out in a condensation device known per se, in particular a condensation device under reduced pressure. It is also possible to perform this condensation treatment of water vapor at low temperature, using a trap, in particular a trap immersed in a bath of liquid nitrogen.

Advantageously and according to the invention, the predetermined temperature is between 20 ^° C. and 95 ^° C., in particular between 25 ^° C. and

70 ^° C., in particular of the order of 70 ^° C. Advantageously and according to the invention, during the osmotic transfer step, the temperature of the liquid extraction composition is maintained at a value of between 5 ^° C. and 95 ^° C.

The invention also extends to a device for carrying out a process according to the invention, comprising: a porous membrane capable of allowing osmosis transfer of at least one compound in the gaseous state between a first main face and a second main face of this porous membrane,

a first circuit, called a supply circuit, adapted to ensure a circulation of a liquid feed composition in contact with said first face of the porous membrane, a second circuit, referred to as an extraction circuit, adapted to ensure a circulation of a liquid extraction composition in contact with said second face of the porous membrane, and in which the supply circuit comprises at least one inlet of a gaseous composition under pressure distinct from the liquid feed composition.

Such a device according to the invention comprises a feed circuit adapted to allow a circulation of the liquid feed composition in the feed circuit and in contact with the first main face of the porous membrane and further comprises an inlet of gaseous composition under pressure, in the feed circuit.

Advantageously and according to the invention, said entry of gaseous composition under pressure comprises a device for selective admission of the gaseous composition into the feed circuit, having at least two positions, adapted so that: in a first position of the device of selective admission of the gaseous composition, said closed position, the gaseous composition under pressure is not introduced into the feed circuit, and, o in a second position of the selective admission device of the gaseous composition, said open position the gaseous composition under pressure is introduced into the feed circuit.

The device for selective admission of the gaseous composition into the feed circuit may be a screw valve, in particular a micrometric screw valve, adapted to allow the flow rate and the pressure of said gaseous composition to be adjusted in the feed circuit. 'food. Thus, it is possible to adapt the flow rate and the pressure of the gaseous composition under pressure in the feed circuit according to the mode of use of the device.

The valve may also be a stop valve having an obstruction lever biased into a closed position by a spring. Thus, the pressure exerted on the stop valve by the user makes it possible to deliver in the circuit feedstock, a quantity of said gaseous composition stored at a pressure above atmospheric pressure in a container, a cartridge or a gas composition distribution network.

Advantageously and according to the invention, said gaseous composition entry under pressure comprises a three-way admission valve, called intake valve, of the gaseous composition under pressure in the feed circuit, adapted so that:

in a first state of the intake valve, the gaseous composition under pressure is introduced into a part of the supply circuit, and does not flow into the complementary part of said portion of the supply circuit,

in a second state of the intake valve, the gaseous composition under pressure flows into the complementary part of the supply circuit and does not flow into the part of the supply circuit comprising the porous membrane,

- In a third state of the inlet valve, the gaseous composition under pressure does not flow into the supply circuit.

Advantageously, using a manual inlet valve, that is to say capable of being actuated by the user, or a robotic valve can be programmed and controlled in the absence of the user. Such an inlet valve is used to successively allow the operations of treatment of the osmotic evaporation liquid feed composition, the purging operations of the liquid feed composition in the feed tank and the evaporative concentration operations. of the liquid extraction composition.

Advantageously and according to the invention, the feed circuit comprises at least one device for stopping the flow of the liquid feed composition and the gaseous composition in the feed circuit. In particular, the supply circuit of an osmotic evaporation device according to the invention comprises two devices for stopping the flow of fluid (s) in the supply circuit, placed in the supply circuit respectively upstream of the gas composition inlet in the supply circuit and downstream of the supply compartment of the membrane contactor.

These flow stop devices may be valves adapted so that in a first state of said valves, the liquid feed composition and / or the gaseous composition flows (s) in the upstream portion of the feed circuit, said upstream part not including the membrane contactor, and so that in a second state of said valves, the liquid feed composition and / or the gaseous composition flows (s) in the downstream portion, complementary to said upstream portion, of the circuit power.

Advantageously and according to the invention, the device for stopping the flow of the liquid feed composition and the gaseous composition in the feed circuit is formed of a dismountable coupling in two parts, comprising an upstream portion and a a complementary downstream part of said upstream part, said removable coupling being adapted so that:

in a first state of said removable connection, said disconnected state, said upstream portion and said downstream portion of the removable connection are dissociated and are hermetic to the liquid feed composition and to the gaseous composition, in a second state of said removable connection, said connected state, said upstream portion and said downstream portion of the removable connector are associated and form a sealed connection to the liquid feed composition and the gaseous composition flowing through said removable connector in the feed circuit. In particular, the flow stop device (s) of the supply circuit are removable connectors adapted so that a leaktight communication of fluids (liquid and / or gaseous) is established between the two parts of said dismountable coupling. that the removable coupling is in a first connected state of said coupling, and that the communication is not established between the upstream and downstream parts of said removable coupling which remain watertight to the composition supply liquid when the removable connection is in a second state disconnected from said connection.

Advantageously, these connections being removable connections in two complementary parts, one of the two parts of the first and second connection is accessible on one of the outer faces of the osmotic evaporation device according to the invention. Thus, the user can easily perform the connection / disconnection operations necessary to conduct an osmotic evaporation operation.

Advantageously and according to the invention, the osmotic evaporation device comprises, as a removable connector (s), an inlet connection of liquid feed composition in the membrane contactor and a liquid composition outlet connection. supplying the membrane contactor selected from the group consisting of zero-drop couplers. Advantageously, the two feed inlet and outlet feed connections are zero-drop type couplers.

Advantageously and according to the invention, at least one of the selective admission device and the inlet valve is an electro valve.

Advantageously and according to the invention, the osmotic extraction device comprises a single temperature control device capable of maintaining the liquid extraction composition at a predetermined temperature of between 5 ⁰ C and 95 ⁰ C.

The inventors have observed that a porous membrane for osmosis transfer of a compound in the gaseous state behaves as a gaseous exchange organ by osmosis, but that it also behaves surprisingly as a heat exchanger. Thus, an osmotic extraction device according to the invention having only one device for regulating the temperature placed in the extraction circuit, in particular placed in the extraction tank, makes it possible to control and regulate the temperature of the composition. extraction liquid, the temperature of the liquid feed composition and the osmotic transfer temperature. Advantageously, such a single temperature control device placed in the extraction solution comprises a temperature control block adapted to regulate the temperature of a thermal regulation fluid circulating in a thermal diffuser immersed in the liquid extraction composition. .

Advantageously, the thermal diffuser immersed in the liquid extraction composition also comprises fast connection and disconnection devices and high security, including zero-drop connections, adapted to put the thermal regulation block in fluid communication with the device. thermal regulation. In a particular mode of use of such an osmotic evaporation device, in which the osmotic evaporator is capable of being transported and moved between two sites of use, disconnecting devices are disconnected quickly, without loss of thermal regulation fluid. Advantageously and according to the invention, the supply circuit comprises at least one pump, in particular a positive displacement pump, in particular a gear pump adapted to generate a flow of the liquid feed composition in the feed circuit and in contact of the first main face of the porous membrane of the membrane contactor, said pump being placed between a supply fluid outlet of the membrane contactor and the supply outlet connection. Preferably, the pump of the supply circuit is interposed in fluid communication between the inlet connection of the liquid supply composition of the osmotic extraction device and the fluid inlet of the membrane contactor, that is to say upstream of the membrane contactor and said gaseous composition inlet.

Advantageously, such a pump of the supply circuit is adapted to withstand the pressure drops of the liquid feed composition in the feed circuit and to allow the circulation of said fluid without the need for a priming operation of said pump . In addition and advantageously such a pump is adapted to allow the flow to be maintained of the liquid feed composition at a constant value despite the increase in the viscosity of said liquid feed composition.

Advantageously and according to the invention, the extraction circuit comprises at least one centrifugal pump adapted to drive the liquid extraction composition into the extraction circuit through the membrane contactor, said centrifugal pump being placed in the extraction circuit. between an extraction of liquid extraction composition of the extraction tank and the entry of liquid extraction composition of the membrane contactor.

Advantageously and according to the invention, the extraction tank comprises a first sensor, said high extraction sensor, the level of liquid extraction composition in the extraction tank. Such a top extraction sensor is advantageously connected to a device for interrupting the circulation of the liquid extraction composition in the extraction circuit, and making it possible to avoid any risk of overflow of said liquid extraction composition. extraction tank.

Advantageously and according to the invention, the extraction tank comprises a second sensor, called low extraction sensor, the level of liquid extraction composition in the extraction tank. Such a low extraction sensor is particularly adapted to indicate to the user that the liquid extraction composition is again ready for use for a subsequent osmotic evaporation step. In addition, such a sensor is adapted to prevent the pump running dry.

Advantageously and according to the invention, the feed tank comprises a flow sensor of the supply fluid in the feed circuit adapted to interrupt the flow of the feed fluid in the feed circuit when the volume of the solution feed has reached a predetermined value. In particular, such a flow sensor can be adapted to interrupt the operation of the pump of the supply circuit.

Advantageously and according to the invention, the osmotic evaporation device is equipped with organs emitting a light signal and / or sound likely to be perceived by the user and testifying to the on / off state of the feed pump, the extraction pump and the state of the means for introducing the gas composition into the circuit power.

Advantageously and according to the invention, a device according to the invention further comprises manual means for switching on / off the feed pump, the extraction pump and the electro-valve for introducing the composition. gas in the supply circuit.

The invention also relates to an osmotic evaporation device and a method using such a device characterized in combination by all or some of the characteristics mentioned above or below.

Other objects, features and advantages of the invention will appear on reading the following description which refers to the appended figures representing preferred embodiments of the invention, given solely by way of non-limiting examples, and in which: FIG. 1 is a schematic out-of-proportion representation of a device according to the invention illustrating a first particular embodiment of a device according to the invention,

FIG. 2 is a schematic out-of-proportion representation of a variant of a device according to the invention; FIG. 3 is a schematic out-of-proportion representation of a device according to the first embodiment illustrating a step of a method; osmotic evaporation,

FIG. 4 is a block diagram illustrating an osmotic evaporation process using an osmotic evaporation device according to the invention.

An osmotic evaporation device 1 according to the invention shown in FIG. 1 comprises a membrane contactor 2 comprising at least one porous membrane 30 for exchanging at least one compound in the gaseous state between a first main face of said membrane. Porous material in contact with a liquid supply composition circulating in a compartment 31 feeding, and a second main face in contact with a liquid extraction composition 3 circulating in a compartment 32 for extracting said membrane contactor 2.

Such a membrane contactor 2 is used so that the liquid feed composition and the extraction liquid composition do not penetrate substantially into the pores of the porous membrane and form within said pores and between the two liquid compositions - which are inherently miscible - a gas separation layer. Thus, the two liquid compositions are not in contact with each other. Such a hydrophobic porous membrane membrane switch 2 interposed between a hydrophilic liquid feed composition and a hydrophilic extraction liquid composition or a hydrophilic porous membrane membrane switch 2 interposed between a liquid feed composition is used. hydrophobic and a hydrophobic extraction liquid composition 3. Preferably a hydrophobic hollow fiber membrane switch 2 is used which forms the porous membrane. In general, the liquid supply composition is in contact with the main face forming the interior of the hollow fibers, and the extraction liquid composition 3 circulates in the calender of the membrane switch 2 and is in contact with the main face forming the outside of the hollow fibers. In particular, it uses a membrane contactor 2 Polypropylene fibers of X40 or X50 kind (Liqui-Cel ^® Extraflow 2,5x8 ", Membrana GmbH, Wuppertal, Germany). We choose such a contactor membrane 2 as a function of pore diameter This diameter may vary between models between 30 nm and 300 nm and the porosity is of the order of 25% to 50%.

As an indication, the Laplace pressure of such a polypropylene fiber membrane contactor 2 having a porosity of 30 nm, whose angle of contact with water is 105 ° C, considering an air / water surface tension of 73.10 ³ N / m, 23500 hPa (23.5 bar). It is also possible to use a membrane contactor 2 to hydrophobic hollow fibers formed of an apolar and hydrophobic polymeric resin of the polyolefin type, in particular of polyethylene (PE), or of the perfluorocarbon type of the PTFE (polytetrafluoroethylene) or PVDF (polyvinylidene difluoride) or PFA (PerFluoroAlcoxy) type or of the polyether thermetone (PEEK) or hydrophobic or hydrophobic ceramic fiber type.

In a particular embodiment of a device according to the invention can be used a membrane contactor 2 comprising hollow fibers formed of a perfluorinated thermoplastic resin based on poly (TFE-co-TFAVE) such as the membrane contactor Phasor ^® II (SAS Entegris, Moirans, France.

However, it is also possible to use as membrane contactor 2, any device comprising a hydrophobic porous membrane having any other shape, in particular a planar porous membrane separating the feed compartment 31 and the extraction compartment 32. Such a membrane switch 2 of a device according to the invention has a fluid inlet 7 in the supply compartment 31 and a fluid outlet 8 of the supply compartment 31. Preferably, it comprises an inlet 10 of extraction liquid composition 3 in the extraction compartment 32 and an outlet 9 of extraction liquid composition 3 of the extraction compartment 32. These inputs 7, 10 and these outlets 8, 9 of the membrane contactor 2 form fluid-tight connections, that is to say to liquids and gases, with hoses of the supply circuit 6 and the circuit 4 of extraction.

The hoses used to form the fluid-tight connections between the components of the supply circuit 6 and the extraction circuit 4 may be flexible thermoplastic polymer pipes. Such a polymer is chosen to chemically resist contact with solvents and saline, neutral, acidic or basic aqueous solutions. It is preferably PVDF (Polyvinylidene fluoride) pipes, in particular PTFE (PolyTetrafluoroethylene). It is also possible to use Tygon ^® 2075 brand pipes (Saint-Gobain, France), or thermoplastic pipes polyamide brand Rilsan ^® . In addition, the pipes forming the feed circuit 6 can be made of stainless steel.

In particular, chemically inert materials are used in contact with the feed liquid composition, the extract liquid composition and the gaseous composition. By material chemically inert to the feed liquid composition, the extraction liquid composition and the gaseous composition is meant a material which does not substantially alter the composition or the liquid composition. feed, or the liquid extraction composition 3, or the gaseous composition 21 as they circulate in the feed circuit 6 and in the extraction circuit 4.

The extraction tank 11 may be a tank made of a material that is inert with respect to the extraction liquid composition, in particular glass, or polyethylene (PE), or high-density polyethylene (HDPE), or polypropylene (PP). Such materials are furthermore capable of being sterilized / decontaminated during moist heat treatment, in particular by autoclaving. In particular, the extraction tank 11 is a storage tank with a volume of the order of 10 L adapted to receive liquid solutions, possibly corrosive, and whose polypropylene screw cap has two sealed inlet manifolds. and output of liquid extraction composition 3 of the extraction circuit 4. Thus, in this particular embodiment, the extraction tank 11 is a sealed tank. For use of an osmotic evaporation device 1 on a pre-industrial scale, especially in the context of a pilot unit, the volume of the extraction tank 11 is preferably greater than 10 L. The extraction tank 11 is equipped with a thermal control device adapted to control and maintain the temperature of the extraction liquid composition 3 at a predetermined temperature. By way of nonlimiting example, a cryo-thermostat is chosen, in particular of the Polystat type (HUBER, Offenburg, Germany) comprising a control interface CC2 and whose external circulation 22 is immersed in the extraction tank 11. The use of a single thermal regulator and a single external circulation 22 in contact with the only extraction circuit 4 makes it possible to reduce the energy consumption of such an osmotic evaporation operation with a conserved evaporation efficiency. The extraction tank 11 may further be equipped with a high level sensor 28 of liquid extraction composition 3. Such a sensor 28 is adapted to detect the increase in the level of liquid in the extraction tank 11 and inform the user that the extraction tank 11 has reached its maximum capacity. Such a high liquid level sensor 28 may be coupled to a device for stopping a centrifugal pump 33 of the extraction circuit 4 or a gear pump 27 of the supply circuit 6.

It is also possible that the tank 11 is equipped with a sensor 34 low liquid level. Such a sensor 34 is adapted to warn the user of the drop in the level of the extraction liquid composition 3 in particular during a recycling operation of the extraction liquid composition 3.

The extraction circuit 4 further comprises a purge 35 of the extraction liquid composition 3 adapted to allow, if necessary, to drain the extraction tank 11 and the extraction circuit 4. A device according to the invention shown in Figure 1, further comprises two pumps adapted to cause the circulation of the liquid feed composition in the feed circuit 6 and the extraction liquid composition 3 in the circuit 4 'extraction. The pumps are selected from centrifugal pumps, including magnetic drive centrifugal pumps and gear pumps. Such pumps are chosen for their performance in the training of a fluid (resistance to pressure, temperature), for their small size and for their reliability in use.

By way of nonlimiting example, a centrifugal pump 33 is chosen, in particular a magnetic drive centrifugal pump, from the MD 20 LC models (IWAKI, Marcoussis, France), MD 70 RZ (M) (IWAKI, Marcoussis, France). Such a centrifugal pump 33 is placed in the lower position in the extraction circuit 4 and allows the circulation of the extraction liquid composition 3 at a flow rate of between 10 kg / h and 650 kg / h. In particular, the centrifugal pump 33 is placed between a low outlet 40 of the extraction vessel 11 and the inlet 10 of extraction liquid composition 3 in the membrane contactor 2. Thus, the centrifugal pump 33 is loaded as soon as the purge 35 is not open.

By way of non-limiting example, a gear pump 27 of the MDG type, in particular MDG H2TA (IWAKI, Marcoussis, France), having a good temperature resistance up to 95 ^° C., and at high pressures up to a maximum of 80.degree. at 6 bars.

Advantageously, such a gear pump 27 is placed in the supply circuit 6. The gear pump 27 allows easy priming of the pump and entrainment of the liquid feed composition in the feed circuit 6. A gear pump may be placed upstream of the membrane switch 2 according to the use made of the device according to the invention.

Advantageously, the pumps 27, 33 are placed in the supply and extraction circuits 6 so that the flow of the fluids is countercurrent in the membrane contactor 2. This gives an optimal osmotic transfer efficiency. However, it is also possible to place the pumps 27, 33 so that the flow of the fluids occurs concurrently.

The flow rate of the liquid compositions 3, 5 in the supply and extraction circuits 6 is controlled by appropriate means known per se, in particular a frequency converter applied across the pumps 27, 33, or a control valve of flow, a bypass bypass device, or by the use of pumps of suitable dimensions to obtain such a flow.

In a first particular application of a device 1 according to the invention, the extraction liquid composition 3 is a solution of a solute with a high concentration in water - in particular a saturated solution of said solute -, adapted to decrease the activity of water in the extraction liquid composition 3. Thus such an extraction liquid composition is adapted to allow the extraction of water from an aqueous liquid feed composition and to increase the concentration of solutes of said aqueous feed liquid composition. The solute of the extraction liquid composition 3 may be a salt of high solubility in water-especially with a solubility of greater than 20 g / 100 ml. The extraction liquid composition 3 is then a brine formed of at least one of the compounds chosen from:

calcium chloride (CaCl ₂ , 22.231-3, Sigma-Aldrich, Saint Louis, MO, USA) at 40% (w / w) in water, or,

bipotassium hydrogenphosphate (K ₂ HPO ₄ , Riedel-de Haen, St. Louis, MO, USA) at 55% (w / w) in water, or,

sodium hydroxide (NaOH, Prolabo, Fontenay-sous-Bois, France) at 30% (weight / weight) in water, or sodium chloride (NaCl) at saturation in water.

The solute of the extraction liquid composition 3 can also be a water-soluble polyol, in particular glycerol (CIP 6193661, Laboratoires Gifrer Barbezat, Decines, France) at 70% (weight / weight) in water.

In a second particular application of a device 1 according to the invention, the extraction liquid composition 3 is a solution of a non-volatile acid in water, in particular sulfuric acid (H ₂ SO ₄ ) or phosphoric acid (H ₃ PO ₄ ), adapted to allow the extraction, neutralization and entrapment of a basic volatile compound, in particular ammonia from an ammonia feed solution. In particular, the concentration of this acid in water is of the order of normality (1 N).

In the particular embodiment of a device 1 according to the invention shown in FIG. 1, the means for introducing the pressurized gaseous composition 21 comprise an inlet 13 of gaseous composition under pressure in the feed circuit 6. device 12 for entering the composition 21 gas under pressure and connections 18, 20 for setting fluid communication the membrane contactor 2 and the liquid supply composition of the feed tank 19. These inlet 18 and outlet 20 connections are located on an outer face of the osmotic evaporation device 1 so as to be easily manipulated by the user. These inlet 18 and outlet 20 connectors are adapted to allow connection / disconnection of two complementary parts of these connectors. They are adapted to form a fluid communication between the part of the internal supply circuit 6 to the osmotic evaporation device 1 and the external supply reservoir 19 to the osmotic evaporation device 1 when the two complementary parts of the connectors 18, 20 are connected.

These inlet 18 and outlet 20 connections are further adapted to form a shutter valve when the two complementary parts are dissociated. In particular, these connectors 18, 28 are chosen from fluid connectors, in particular zero-drop couplers. By way of example, such a zero-drop coupler may be of NS4 type (Colder Products Company GmbH, Mainz-Kastel, Germany). In particular, a zero-drop coupler made of a material chosen from polypropylene, glass-filled polypropylene, having a chemical compatibility with the solvents and / or the basic, acidic or neutral aqueous salt solutions used. Depending on the applications, such a coupler may be of the cap type or of the fluted line connection type.

A device according to the invention shown in Figure 1 further comprises a purge member 35 of the liquid extraction composition 3 of the extraction circuit 4. Such a purge member 35 is adapted to allow the extraction circuit 4 to be emptied in order to replace said extraction liquid composition 3.

The feed tank 19 of a device 1 according to the invention may comprise a low liquid level sensor 29 adapted to detect the drop in the level of the feed solution in the feed tank 19 during a feed. step 40 of an osmotic evaporation treatment. Such a sensor 29 may be further connected to a device for stopping the pump 27 of the circuit 6 supply and / or the pump 33 of the extraction circuit 4 so as to interrupt the flow of the extraction liquid composition 3 in the extraction circuit 4 and the supply solution 5 in the circuit 6 when the required level of the feed solution in the feed tank 19 is reached. A device according to the invention shown in FIG. 1 may comprise a sensor 37 for the flow of the gaseous composition 21 under pressure in the supply circuit 6. Such a flow sensor 37 may be coupled to a visual or audible warning device and is adapted to rapidly indicate to the user the activated operating mode of the device 1 according to the invention. Such an osmotic evaporation device according to the invention further comprises a device for measuring the flow rate of the liquid feed composition in the supply circuit 6. Such a measuring device may be coupled to a visual or audible warning device and is adapted to alert the user to the risk of damage to the gear pump 27 as soon as the gear pump 27 operates in the absence of a composition. feed liquid.

In a second variant of a device 1 according to the invention shown in FIG. 2, the means 23 for introducing the pressurized gas composition 21 comprise a three-way admission valve 24 adapted to place in alternately two fluid communication three inputs of said inlet valve 24.

Thus, in a first position of the inlet valve 24, the gas composition 21 is not introduced into the feed circuit 6, and the feed liquid composition flows from the feed tank 19 through the inlet fitting 18 of the liquid supply composition, into the pump 27, then through the inlet valve 24, into the supply compartment 31 of the membrane switch 2 through the connection 20 of the liquid feed composition outlet and opens into the feed tank 19.

In a second position (not shown) of the inlet valve 24, the gas composition 21 under pressure is introduced into the circuit 6 and feeds into the complementary portion of the feed circuit 6 not including the membrane switch 2, passes through the inlet fitting 18 of liquid feed composition and purges said complementary portion of the feed circuit 6 into the 19 supply tank. The gaseous composition 21 under pressure is not introduced into the complementary part of the feed circuit 6 comprising the membrane contactor 2.

In a third position of the inlet valve 24, the pressurized gaseous composition 21 is introduced into the supply circuit 6 and circulates in the complementary part of the supply circuit 6 comprising the membrane contactor 2 and purges the liquid composition. supplying said complementary part (comprising the supply compartment 31 of the membrane contactor 2). The pressurized gaseous composition 21 is not introduced into the complementary part of the feed circuit 6 which does not comprise the membrane contactor 2. In this second variant of an osmotic evaporation device 1 according to the invention shown in FIG. 2, the inlet and outlet fittings 18 and 20 of liquid feed composition in the osmotic evaporation device 1 are in connected position and the liquid supply composition flows into the feed circuit 6. In an osmotic evaporation device 1 according to the invention shown in FIG. 2, it is not necessary to alternatively disconnect the inlet and outlet connections 18 and 20 from the liquid supply composition in order to purge the feed circuit 6. Alternative introduction of the gas composition 21 into the feed circuit 6 is effected by successively placing said three-way intake valve 24 in said second and third positions.

In a third variant of an osmotic evaporation device 1 shown in FIG. 3, the pressurized gaseous composition 21 is contained in a cartridge 36 of pressurized gas. In particular the cartridge 36 of pressurized gas is placed in fluid communication with the supply circuit 6. The inlet means of the gas composition 21 under pressure in the supply circuit 6 of the device 1 comprises a device 12 for selective admission of the pressurized gas composition 21 formed of a micrometric screw valve and adapted to put the supply circuit 6 in fluid communication with the composition 21 and to control the inlet flow and pressure of said gas composition 21 in the feed circuit 6.

The pressurized gaseous composition 21 may be formed of compressed atmospheric air from a compressed air distribution network. Then, it will be preferred to purify said compressed air by filtering on porosity filter substantially of the order of 0.2 microns to remove the oils generated by the compressor and the particles in suspension in the compressed air.

As gaseous composition 21, it is also possible to use a reserve of a gas or of several liquefied gases under pressure, in particular a gas cylinder equipped with a pressure reducer and a micro metric valve for regulation. flow. Depending on the grade of liquefied gas under pressure in the bottle, the gas can be used directly without purification or it may be preferable to purify the gas by filtration.

In the third variant of an osmotic evaporation device 1 shown in FIG. 3, the inlet connection 18 of the liquid supply composition in the osmotic evaporation device 1 is in the disconnected position, and a communication is established. fluid between the cartridge 36 of composition 21 gas under pressure and the supply circuit 6 by the device 12 for input of said gas composition 21. The pressurized gaseous composition 21, distinct and immiscible with the feed liquid composition, flows into the feed circuit 6 and moves the feed solution into the feed compartment 31 to the feed connection 20. output of the liquid supply composition and the feed tank 19. Then, the fluid communication between the cartridge 36 and the supply circuit 6 is interrupted by the device 12 for inputting said pressurized gas composition 21, the fluid inlet fitting 18 is connected, the connector 20 is disconnected. fluid outlet and a fluid communication is established between the cartridge 36 of gas composition 21 and the supply circuit 6 by the device 12 for inputting said pressurized gas composition 21. The pressurized gaseous composition 21 flows into the supply circuit 6 and moves the supply solution 5 from the complementary part of the feed circuit 6 not including the feed compartment 31 to the feed connection 18. input of the liquid feed composition and to the feed tank 19.

In a process for treating a liquid feed concentrate composition shown in FIG. 4, a device 1 according to the invention is used in which a osmotic evaporation step 40 is carried out between the liquid feed composition and a liquid extraction composition 3. This osmotic evaporation step is carried out for a time sufficient to allow the osmotic transfer of water from the feed solution to the extraction liquid composition, in particular brine. In particular, for this osmotic evaporation step 40, in which the temperature of the extraction liquid composition is set at 20 ^° C., the solute concentration of the feed solution is multiplied by a factor of 10 min, thus generating a flow of water between the two main faces of the membrane contactor 2 of 0.6 L / h. For this osmotic evaporation step 40 conducted at 50 ^° C., the value of the flow of water is 4.3 L / h.

In a subsequent purge step 41, during which a quantity of gaseous composition 21 is introduced into the feed circuit 6 of an osmotic evaporation device 1, the liquid concentrate feed composition 51 of the circuit 6 is moved. supply and the compartment 31 for supplying the membrane switch 2 to the supply tank 19.

During a step 42 for recycling the extraction liquid composition 3, a flow of gaseous composition 21 is formed in the feed circuit 6 of the osmotic evaporation device 1, capable of being charged with water vapor. and the temperature of the extraction liquid composition 3 is brought to a value of between 20 ^° C. and 95 ^° C. The liquid extraction composition 3 is thus recycled. and forming water vapor which can be captured by bubbling in a condensation composition 43. It is also possible to eliminate this water vapor in any device known per se for the treatment of water vapor or toxic substances such as a fume hood of a laboratory. In particular, in a step 42 for recycling the extraction liquid composition 3, a gaseous composition 21 substantially free of water vapor is used as the gaseous composition 21 under pressure. Such a pressurized dry gas composition 21 is adapted to concentrate a brine extraction liquid composition 3 for recycling said brine at a subsequent osmotic evaporation step.

In a fourth variant of an osmotic evaporation process represented in FIG. 4, comprising a step 42 for recycling a liquid extraction composition 3 and implemented in an osmotic evaporation device 1 represented in FIG. places the inlet valve 24 in said third position so as to put the inlet of said gaseous composition 21 in fluid communication with the portion of the supply circuit 6 comprising the supply compartment 31 of the membrane switch 2. The pressurized gaseous composition 21 introduced into the supply circuit 6 circulates in the complementary part of the feed circuit 6 comprising the membrane contactor 2 and opens outwardly from the osmotic evaporation device 1 according to the invention.

In a fifth variant, not shown, of a method according to the invention comprising a recycling step 42, the feed composition input coupling 18 is disconnected so that said connector 18 is disconnected and hermetically sealed and the coupling is connected. 20 with a partial evacuation device of the feed loop 6. In addition, there is interposed between the device for partial evacuation of the feed loop 6 and the supply compartment 31, a device adapted to allow the condensation of the water vapor extracted from the extraction composition 3. EXAMPLE 1 Porous Hollow Fiber Modules osmotic evaporation.

An osmotic evaporation operation is carried out at 40 ^° C. with a device according to the invention comprising a porous membrane contactor (Column A, Column B), in which the feed solution and the extraction solution are formed respectively from 1.5 L of pure water and a solution of glycerol at 80% in water. The extraction solution and the feed solution flow countercurrent to each other, each with a flow rate of 100 L / h.

By way of comparative example, an osmotic evaporation operation is carried out under the same conditions with a non-porous dense membrane switch (column C) for gas permeation. Such a gas permeable and liquid impermeable membrane is not an osmotic evaporation membrane.

The characteristics of the contactors used and the results obtained are given in Table 1 below.

Table 1

EXAMPLE 2 - Laplace pressure of porous membranes Table 2 below gives the values of the Laplace pressure (P) for porous membranes made of different materials and for a liquid aqueous extraction composition.

Table 2

EXAMPLE 3 Influence of the Nature of the Solute of the Liquid Extraction Composition on the Average Stream of Water Vapor

Is carried out an evaporation operation osmo tick with a device according to the invention comprising a membrane contactor Liqui-Cel ^® Extraflow 2,5x8 "wherein the feed solution and the extraction solution to circulate against the current. It is estimated the average flow of the water vapor exchanged, said average osmotic flow, between the two main faces of the membrane contactor by weighing the bottles containing the feed solution and the extraction solution. between 250 kg / h and 300 kg / h The results are given in Table 3 below.

Table 3

The highest average water vapor flow is obtained with the extraction solution comprising 30% sodium hydroxide (NaOH). For reasons of safety of use of the extraction solution, the solution of calcium chloride, giving an average flow of 0.89 L / h remains recommended.

EXAMPLE 4 - Evaluation of the average flow of water vapor in L / h / m ² .

Is carried osmotic evaporation operation at the temperature of 35 ⁰ C with a device comprising a membrane contactor Liqui-Cel ^® Extraflow 2,5x8 "as described in Example 1 (Column A) and wherein the solution of The feed and the extraction solution are respectively pure water and a solution of sodium hydroxide in a mass proportion of 30% in water The flow rate of the feed and extraction solutions is 100 L The initial volume of the feed solution is 2 L and the initial volume of the extraction solution is 5 L. The average flow of water vapor measured is 0.81 L / h / m. .

EXAMPLE 5 Influence of the CaCl ₂ Concentration of the Extraction Solution on the Average Water Flow The average osmotic flow obtained in an osmotic evaporation experiment as described in Example 2 is evaluated. The solute of the extraction solution is calcium chloride (CaCl ₂ ), the mass concentration of which varies between 10% and 40%. %. In addition, the flow rate of the extraction solution is measured in the extraction compartment (calender) of the membrane contactor. The results are given in Table 4 below.

Table 4

A maximum flux value is obtained with an extraction solution containing a mass proportion of CaCl ₂ of 40%. EXAMPLE 6 - Effect of flow rate of the extraction solution on the initial flow of steam: contactor Liqui-Cel ^® Extraflow 2,5x8 ".

Measuring the initial water vapor flux created at 25 ⁰ C in a membrane contactor Liqui-Cel ^® Extraflow 2,5x8 "having an exchange surface of 1.4 m, between 2 L of a solution feed of pure water and 8 L of a 40% (w / w) aqueous solution of CaCl ₂ as a function of the flow rate of the extraction solution for a constant flow rate of the feed solution (110). L / h) The measured value of the initial water vapor flow, given in Table 5 below, ie the flow of water vapor measured after 5 min of evaporation, remains the order of 0.80 L / h for a flow rate of the extraction solution of between 10 L / h and 200 L / h To reduce the energy cost of the osmotic evaporation, the flow rate of the extraction solution adapted to provide an optimum flow of water vapor is set at a value of the order of 50 L / h.

EXAMPLE 7 - Influence of the temperature of the extrusion composition on the initial steam flow: Liqui-Cel ^® Extraflow contactor

2,5x8 ".

Measuring the initial water vapor stream generated at 15 ⁰ C, 25 ⁰ C, 35 ⁰ C, 45 ⁰ C, 55 ⁰ C and 65 ⁰ C in a membrane contactor Liqui-Cel ^® Extraflow 2,5x8 "between 2 L of a feed solution of pure water and 8 L of a 41% (w / w) CaCl ₂ extraction solution in water for a constant flow of the feed solution ( 110 L / h) The flow rate of the extraction solution is 50 L / h The measured value of the initial water vapor flow is given in Table 6 below as well as the time required to reduce the volume. of the feed solution from 2 L to 200 mL.

Table 6

EXAMPLE 8 - Effect of temperature of the extraction composition on the initial water vapor stream: contactor Entegris Phasor II ^®.

Measuring the initial water vapor stream generated at 25 ⁰ C and 45 ⁰ C in a membrane contactor Entegris Phasor II ^®, between 2 liters of a feed solution formed from pure water and 8 L of a solution aqueous extraction of CaCl ₂ at 41% (w / w) for a constant flow rate of the feed solution (110 L / h). The flow rate of the extraction solution is 33.2 L / h. The measured value of the initial water vapor flow is given in Table 7 below as well as the time required to bring the volume of the feed solution from 2 L to 200 mL.

Table 7

EXAMPLE 9 Concentration of an aqueous solution of ammonia

An osmotic evaporation transfer operation is carried out between a feed solution formed of an aqueous ammonia solution at 7800 ppm, the pH of which was brought to 2 by the addition of HCl and an extraction solution consisting of a solution of calcium chloride (CaCl ₂ ) in a proportion by weight of 40% in water. This transfer operation is carried out at the temperature of 25 ⁰ C with a device comprising a membrane contactor Liqui-Cel ^® Extraflow 2,5x8 "as described in Example 1. The flow rate of each of the feed solutions and extraction is 100 L / h. The initial volume of the aqueous ammonia solution is 2 L and the initial volume of the calcium chloride solution is 5 L. The volume of the aqueous ammonia solution is reduced from 2 L to 400 mL. measured water vapor is 0.82 L / h / m ² for a transfer time of 117 min and 0.70 L / h / m ² for a transfer time of 137 min.

EXAMPLE 10 Extraction of Ammonia From an Aqueous Solution

An osmotic evaporation transfer operation is carried out between a feed solution consisting of a 40,000 ppm aqueous ammonia solution (pH 11) and an extraction solution consisting of a sulfuric acid solution (H ₂ SO ₄ ) at a concentration of 0.2 M in water. It performs this transfer operation at a temperature of 4O ⁰ C with a device comprising a membrane contactor Liqui-Cel ^® Extraflow 2,5x8 "as described in Example 1. The flow rate of each of the feed solutions and extraction is 100 L / h The initial volume of the aqueous ammonia solution is 400 mL and the initial volume of the sulfuric acid solution is 5 L. The average ammonia flux measured is 94 g / h for a transfer time of 10 min The final concentration of ammonia in the feed solution is 10 ppm.

EXAMPLE 11 Extraction of ethanol from a hydroalcoholic solution

An osmotic evaporation transfer operation is carried out between a feed solution consisting of a 15% hydroalcoholic solution (volume proportion of 15% of ethanol in water) and an extraction solution formed of pure water. It performs this transfer operation at the temperature of 25 ⁰ C with a device comprising a membrane contactor Liqui-Cel ^® Extraflow 2,5x8 "as described in Example 1. The flow rate of each of the feed solutions and extraction is 100 L / h The initial volume of the hydro-alcoholic solution is 2 L and the initial volume of the extraction solution is 5 L. After 1 hour of osmotic transfer, the concentration of ethanol in the feed solution is 5% and the concentration of ethanol in the extraction solution is 5%. EXAMPLE 12 Purge of the feed solution

Under the experimental conditions presented in Example 2, 930 g of liquid water are introduced into the feed tank of a device according to the invention and a circulation of said water is established in the feed circuit. The circulation of water in the feed loop is stopped and an overpressure in the extraction loop is maintained of the order of 30O hPa (0.3 bar). A gaseous composition is introduced into the feed loop at an overpressure (500 hPa, 0.5 bar) with respect to the atmospheric pressure adapted to move water from the feed loop to the reservoir. The quantity of water collected is weighed (923 g ± 3 g). The average water loss is 8 g, ie less than 1% of the initial water. The loss of water during purging of the feed loop represents approximately 4% of the volume of the feed loop.

EXAMPLE 13 - Recycling of the extraction brine. As shown in Example 7, 1.8 L of water were evaporated and transferred to the extraction solution by means of a contactor liquids Cel ^® Extraflow 2,5x8 ". After purging the loop supply as described in Example 12, is introduced into the supply circuit of atmospheric air dry at room temperature, the temperature of the extraction solution being maintained at 50 ^° C. The flow of dry air in the feed circuit is of the order of 1.8 m ³ / h and the excess pressure of the dry air in the membrane contactor relative to the atmospheric pressure, is of the order of 400 hPa (0.4 The recycling time required to reduce the volume of extraction solution by 1.8 L is of the order of 10.5 hours.

EXAMPLE 14 - Recycling of the extraction brine.

A recycling of 9.8 L of a 32% (w / w) solution of CaCl ₂ in water maintained at a temperature of 65 ^° C. is carried out by circulating this solution at a rate of 100 L / h in the extraction loop of an osmotic transfer device comprising a contactor Liqui-Cel ^® Extraflow 2,5x8 ". are introduced into the atmospheric air supply circuit ambient temperature with a flow rate of 800 L / h The flow of moisture-laden air at the outlet of the membrane contactor is oriented towards a condenser adapted to allow the condensation of the water vapor and its recovery. to reduce the volume of the extraction solution by 1.8 L, it is of the order of 22.5 h The average water vapor flux calculated for this evaporation is 0.06 L / h / m ² .

Claims

1 / Osmotic evaporation process in which:

- a porous membrane (30) adapted to allow osmosis transfer of at least one compound in the gaseous state between a first main face and a second main face of this porous membrane (30),

at least one osmotic transfer step (40) is carried out in which: a liquid feed composition (5) is circulated in a first circuit, said supply circuit (6), in contact with said first main face; the porous membrane (30), said supply circuit (6) comprising a supply reservoir (19) for liquid supply composition (5); circulating a liquid extraction composition (3) in a second circuit, said extraction circuit (4), in contact with said second main face of the porous membrane (30), said liquid composition (3) of extraction exerting a pressure, called extraction pressure, on said second main face by a value less than the Laplace pressure of said porous membrane (30) and said liquid extraction composition (3), characterized in that after said osmotic transfer step (40), a purge step (41) of the supply circuit (6) is carried out in which at least one fluid inlet (13) of the communication supply circuit (6) is placed. with a source of composition (21) gaseous under pressure, immiscible with the composition (5) liquid feed, and adapted to exert a pressure, called gas pressure, in said circuit (6) feeding a higher value at the value of the atmospheric pressure and to move the liquid supply composition (5) of the feed circuit (6) into the feed tank (19).

2 / A method according to claim 1, characterized in that the gaseous composition (21) is chosen from the group consisting of atmospheric air, nitrogen, rare or inert gases, in particular argon and helium, and one of their mixtures.

3 / A method according to one of claims 1 or 2, characterized in that the porous membrane (30) is selected from the group formed by porous hydrophobic hollow fibers.

4 / A method according to one of claims 1 to 3, characterized in that it circulates the liquid supply composition (5) and the countercurrent extraction liquid composition (3) in contact with the first and second faces respectively. of the porous membrane (30).

5 / A method according to one of claims 1 to 4, characterized in that purge sequentially a first portion of the circuit (6) for supply into the reservoir (19) of supply, then purge a second complementary portion of supply circuit (6) in the supply tank (19).

6 / A method according to one of claims 1 to 5, characterized in that, after the step (40) of osmotic transfer, at the conclusion of which is formed a solution (51) liquid concentrated feed and a composition (3) diluted extraction liquid, a step (42) is carried out for recycling the diluted liquid extraction composition (3), in which: the liquid extraction composition (3) is maintained diluted to a predetermined temperature; maintaining the flow of the diluted liquid extraction composition (3) in the extraction circuit (4), so that the extraction pressure is lower than the Laplace pressure of said porous membrane (30), the fluid inlet (13) of the supply circuit (6) is brought into communication with the gas composition source (21), the said gas composition (21) being capable of loading a compound of the composition ( 3) extraction liquid in the gaseous state. Process according to Claim 6, characterized in that the predetermined temperature is between 20 ^° C. and 95 ^° C., in particular of the order of 70 ^° C.

8 / A method according to one of claims 1 to 7, characterized in that, during the osmotic transfer step (40), the temperature of the liquid extraction composition (3) is maintained at a value between ⁰ C and 95 ⁰ C.

9 / osmotic extraction device (1) for implementing a method according to one of claims 1 to 8, comprising:

a porous membrane (30) capable of allowing an osmosis transfer of at least one compound in the gaseous state between a first main face and a second main face of this porous membrane (30),

- A first circuit, said circuit (6) for supply, adapted to ensure a circulation of a liquid supply composition (5) in contact with said first face of the porous membrane (30), - a second circuit, said extraction circuit (4), adapted to ensure a circulation of a liquid extraction composition (3) in contact with said second face of the porous membrane (30), characterized in that the feed circuit (6) comprises at least one inlet (13) of a composition (21) gas under pressure distinct from the liquid composition (5) feed.

10 / Apparatus according to claim 9, characterized in that said inlet (13) of composition (21) gaseous under pressure comprises a device (12) for selective admission of the composition (21) gas in the circuit (6) of supply, having at least two positions, adapted so that: o in a first position of the device (12) selective admission of the composition (21) gaseous, said closed position, the composition (21) gaseous under pressure is not introduced into the supply circuit (6), and, o in a second position of the device (12) for the admission of the gas composition (21), called the open position, the composition (21) pressurized gas is introduced into the supply circuit (6). 11 / Apparatus according to one of claims 9 and 10, characterized in that said inlet (13) of composition (21) gas under pressure comprises a three-way intake valve, said valve (24) intake, the composition (21) gaseous under pressure in the feed circuit (6), adapted so that:

in a first state of the inlet valve (24), the gas composition (21) under pressure is introduced into a part of the supply circuit (6), and does not flow into the complementary part of said first portion of the feed circuit (6),

in a second state of the inlet valve (24), the pressurized gas composition (21) flows into the complementary part of the supply circuit (6) and does not flow into the part of the circuit ( 6) comprising the porous membrane (30), - in a third state of the inlet valve (24), the pressurized gas composition (21) does not flow into the supply circuit (6). .

12 / Apparatus according to one of claims 9 to 11, characterized in that the circuit (6) for supply comprises at least one flow stop device of the composition (5) liquid feed and / or the composition

(21) gas in the supply circuit (6).

13 / Apparatus according to claim 12, characterized in that the flow stop device of the composition (5) liquid feed into the supply circuit (6) is formed of a removable connection in two parts, comprising an upstream part and a complementary downstream part of said upstream part, said removable coupling being adapted so that:

in a first state of said removable connection, said disconnected state, said upstream portion and said downstream portion of the removable connection are dissociated and are hermetic to the liquid supply composition and to the gaseous composition, in a second state of said removable connector, said connected state, said upstream portion and said downstream portion of the removable connector are associated and form a tight connection to the liquid supply composition and the gas composition which is flow through said removable connector in the supply circuit (6).

14 / Apparatus according to claim 13, characterized in that the device (1) of osmotic extraction comprises, as a connection (s) removable (s), a connection (18) input of the composition (5) liquid in the membrane contactor (2) and an outlet connection (20) of the liquid supply composition (5) of the membrane contactor (2) selected from the group consisting of zero-drop couplers.

15 / Apparatus according to one of claims 11 to 14, characterized in that at least one of the device (12) for selective admission and the inlet valve (24) is an electro valve.