Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
  • F28D7/00—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall
  • F28D7/16—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall the conduits being arranged in parallel spaced relation
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D1/00—Evaporating
  • B01D1/0011—Heating features
  • B01D1/0041—Use of fluids
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D1/00—Evaporating
  • B01D1/04—Evaporators with horizontal tubes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D1/00—Evaporating
  • B01D1/06—Evaporators with vertical tubes
  • B01D1/065—Evaporators with vertical tubes by film evaporating
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D1/00—Evaporating
  • B01D1/22—Evaporating by bringing a thin layer of the liquid into contact with a heated surface
  • B01D1/221—Composite plate evaporators
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D5/00—Condensation of vapours; Recovering volatile solvents by condensation
  • B01D5/0003—Condensation of vapours; Recovering volatile solvents by condensation by using heat-exchange surfaces for indirect contact between gases or vapours and the cooling medium
  • B01D5/0009—Horizontal tubes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D5/00—Condensation of vapours; Recovering volatile solvents by condensation
  • B01D5/0003—Condensation of vapours; Recovering volatile solvents by condensation by using heat-exchange surfaces for indirect contact between gases or vapours and the cooling medium
  • B01D5/0015—Plates
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D5/00—Condensation of vapours; Recovering volatile solvents by condensation
  • B01D5/0057—Condensation of vapours; Recovering volatile solvents by condensation in combination with other processes
  • B01D5/006—Condensation of vapours; Recovering volatile solvents by condensation in combination with other processes with evaporation or distillation
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/02—Treatment of water, waste water, or sewage by heating
  • C02F1/04—Treatment of water, waste water, or sewage by heating by distillation or evaporation
  • C02F1/043—Details
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
  • F28D21/00—Heat-exchange apparatus not covered by any of the groups F28D1/00 - F28D20/00
  • F28D21/0015—Heat and mass exchangers, e.g. with permeable walls
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
  • F28D3/00—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium flows in a continuous film, or trickles freely, over the conduits
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
  • F28D9/00—Heat-exchange apparatus having stationary plate-like or laminated conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
  • F28F13/00—Arrangements for modifying heat-transfer, e.g. increasing, decreasing
  • F28F13/003—Arrangements for modifying heat-transfer, e.g. increasing, decreasing by using permeable mass, perforated or porous materials
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
  • C02F2103/08—Seawater, e.g. for desalination
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
  • F28D21/00—Heat-exchange apparatus not covered by any of the groups F28D1/00 - F28D20/00
  • F28D2021/0019—Other heat exchangers for particular applications; Heat exchange systems not otherwise provided for
  • F28D2021/0061—Other heat exchangers for particular applications; Heat exchange systems not otherwise provided for for phase-change applications
  • F28D2021/0066—Other heat exchangers for particular applications; Heat exchange systems not otherwise provided for for phase-change applications with combined condensation and evaporation

Definitions

• the present invention relates to the field of water treatment for the purpose of producing drinking water and/or water for industrial use.
• demineralized water process water or service water
• drink water we are mainly talking about that produced by utility companies to supply public or community distribution networks.
• the invention relates to water desalination processes, in particular to distillation processes using one or more heat exchangers.
• heat exchanger is meant within the meaning of the present invention, an evapo-condenser, an evaporator-condenser exchanger or even a latent heat exchanger.
• Such processes in particular make it possible to produce drinking water and/or water for industrial use of water by desalination by implementing a process for distilling a liquid to be treated on at least one heat exchanger which ensures by heat transfers, d on the one hand, evaporation and, on the other hand, condensation.
• sea water any water taken from the marine environment whose salt concentration is typically greater than or approximately equal to 30 g/L.
• brackish water covers raw water whose salinity is between approximately 1 g/L and the salinity of seawater. mixtures between borehole water and sea water.
• industrial waste water or domestic waste water can also be considered.
• the product of the treatment of this water is generally either used as water for industrial use, or reinjected into the natural environment, or, if the quality allows it, used in irrigation networks or directly diluted in drinking water networks.
• heat exchangers used in such processes are typically built in one piece and comprise an upper part with the aid of which the liquid to be treated is introduced therein and a lower part with the aid of which at least one product is extracted from the treated liquid after treatment of the liquid to be treated.
• heat exchangers are characterized, among other things, by an overall heat transfer coefficient, a layer assembly configuration, an exchange surface and a bulk or volume.
• the heat exchangers currently used are typically installed in an enclosure which first serves as a means of collecting the primary steam.
• the enclosure also allows the implementation of the evaporation condensation process at a pressure different from atmospheric pressure, and in this case the heat exchangers work at an equilibrium temperature, or vapor temperature, different from 100°C.
• this equilibrium temperature is lower than 65° C. in order, on the one hand, to reduce the problems and risks related to scaling, and secondly to increase the efficiency of the thermodynamic cycles of these heat exchangers.
• Each subassembly is defined as a portion of a given heat exchanger.
• Each of the heat exchanger sub-assemblies includes:
• the layer of thermally conductive material being located between the evaporation surface and the condensing surface, this material being configured to transfer at least part of the latent heat of condensation from the condensing surface to the evaporating surface, the evaporating surface being typically opposed to the condensing surface.
• the heat transfers carried out by the thermally conductive materials of each of the subsets of current heat exchangers mainly consist of a latent heat of condensation which is directly restored through the thermally conductive material and which ensures the phenomenon of evaporation.
• These heat transfers are made possible thanks, among other things, to the application of a temperature differential, and also of pressure in particular, between the evaporation surface and the condensation surface of one of the sub-assemblies of the exchanger thermal.
• the primary vapor resulting from the evaporation of the liquid to be treated which spreads over the evaporation surfaces of the heat exchanger.
• This primary vapor circulates on the side of the evaporation surfaces in the primary vapor spaces.
• the secondary steam which is intended to be condensed on the heat exchanger, circulates on the side of the condensing surfaces of the heat exchanger, in the secondary steam spaces.
• Each of the condensation surfaces is generally opposed, for a layer of thermally conductive material of the heat exchanger, to one of the evaporation surfaces of the heat exchanger.
• the secondary vapor is condensed on the same heat exchanger, whereas in a multiple-effect configuration (either multi-stage mechanical compression or a MED), the secondary steam is condensed on a heat exchanger arranged downstream, that is to say on the heat exchanger of the next effect.
• a multiple-effect configuration either multi-stage mechanical compression or a MED
• the primary vapor generated at an evaporation surface of a sub-assembly is caused to flow into the heat exchanger through, in particular, any primary vapor space present in each subsets.
• this primary vapor circulates from the evaporation surface linked to a thermally conductive material of a subset towards another conductive material, in particular towards another evaporation surface, of another subset of the heat exchanger, said other sub-assembly possibly being a sub-assembly adjacent to said sub-assembly but not necessarily.
• the steam generated by the evaporation called primary steam
• the primary vapor spaces until it leaves the volume of the exchanger, then is brought by the process implemented on the condensation surfaces of the heat exchanger.
• the vapors of the liquid being treated called secondary vapor and in particular the water vapours, condense and produce the condensate, and the vapors of the compounds whose boiling point is lower than the process temperature constitute the non-condensable gases which must be extracted from the condensation spaces.
• the primary steam also circulates along available paths between the evaporation surfaces of the thermally conductive materials of the heat exchanger and the outer limits of the heat exchanger. For example, these paths can, or must as the case may be, cross primary vapor spaces linked to the evaporation surfaces of other subsets.
• the liquid to be treated is typically supplied and distributed over the upper part of the heat exchanger and travels, under the effect of gravity and thanks to the design of the exchanger, all the evaporation surfaces of the heat exchanger. exchanger until the extraction or less partial of the treatment product in its lower part.
• the evaporation-condensation process only part of the liquid to be treated is evaporated. For example, given that the salts contained in the liquid to be treated cannot be evaporated under the conditions of implementation of the process, they remain in the liquid to be treated and as a result the salinity of the liquid to be treated increases as the process progresses. and as the latter progresses over the surfaces of the exchanger during its movement between its upper part and its lower part.
• heat exchangers There are a multitude of types of heat exchangers that can be used in such processes. These heat exchangers come in different shapes and configurations. For example, heat exchangers can comprise several layers of thermally conductive materials in the form of tube bundles (FIG. 13) or in the form of plates forming alternate evaporation and condensation chambers (FIG. 12). According to different configurations, the evaporation can thus be implemented inside these tubes or these chambers, or else outside. It should also be noted that the tubes or chambers of the heat exchangers can be arranged horizontally or vertically or can even be inclined. It should be noted that heat exchangers designed to implement a thin film of falling water (film falling in French and commonly referred to by the English acronym TFF for Thin Falling Film) display the best overall heat transfer coefficients but are d greater volume or bulk.
• TFF Thin Falling Film
• state-of-the-art heat exchangers that do not use a thin falling film are not very compatible with uses with a low temperature differential between the condensation surfaces and the evaporation surfaces.
• state-of-the-art heat exchangers that do not employ thin falling film may be those whose primary vapor spaces are at least partially filled with the liquid to be treated or being treated.
• the primary vapors must escape from the volume of the heat exchanger crossing a space at least partially filled with the liquid to be treated, or being treated, and this generates hydraulic pressure drops which require the implementation of a higher pressure differential, namely an associated differential of temperatures above 2 to 5°C.
• the installation generally also includes other elements such as ducts which are necessary for the collection and extraction of non-condensable gases in particular.
• the condensate that is collected and extracted from such an installation can be intended for the domestic or industrial user.
• the concentrate which is collected and extracted from such an installation is generally discharged into the natural environment.
• concentrate is meant within the meaning of the present invention, the portion of a liquid to be treated, or during treatment, which has not evaporated during its progression on the evaporation and/or condensation surfaces of the heat exchanger, and whose salinity has increased. The concentrate is usually discarded.
• non-condensable gas is meant within the meaning of the present invention, the vapors of the compounds of a liquid to be treated whose boiling point is lower than the setting temperature. implementation of the process and which, therefore, have been evaporated but cannot condense at the conditions implemented.
• condensate is meant within the meaning of the present invention, the product of the condensation of a water vapor generated by the evaporation of part of the liquid to be treated.
• the condensate which may also be referred to as distillate when it is a single-effect unit, is the product of the treatment.
• the interior volume of currently known heat exchangers are made up of layers of thermally conductive materials with thicknesses of the order of 0.8 to 1.5mm, in particular to meet three constraints:
• the high thickness of the external walls also serves to integrate the phenomenon of reduction in the thickness of the external wall by erosion or corrosion in order to allow operation over a period of more than 20 years or more.
• the performance of large heat exchangers is limited.
• the specific exchange surface per volume that characterizes them is, in the case of thin falling film heat exchangers, limited to 40, or even 80m 2 /m 3 and their overall heat transfer coefficient is also limited to 3500 W/m 2 .K, even at 6500 W/m 2 .K.
• the heat exchangers currently used are generally made to measure and in one piece in their enclosure and have large volumes and weights making them difficult to dismantle or move.
• One of the aims of the invention is to remedy the shortcomings of the methods and devices or liquid desalination systems of the state of the art.
• the present invention relates to a heat exchanger comprising several subassemblies consisting in part of a layer of a thermally conductive material, the heat exchanger comprising:
• the heat exchanger being defined by a volume divided into several zones, the heat exchanger being characterized in that each of the zones comprises at least:
• an extractor means configured to channel at least part of the primary steam generated in the zone towards the outside of said volume.
• the heat exchanger is configured in particular so that the primary steam is found in conditions which allow its evaporation and the secondary steam, in conditions allowing its condensation.
• the secondary steam is defined by a temperature and a pressure higher than those of the primary steam.
• zone within the meaning of the present invention, is meant a portion of the heat exchanger, which is virtually defined or materially separable, comprising at least one subassembly and one extractor means.
• Two successive zones can be separated from each other by a part of the heat exchanger.
• two successive zones may or may not be adjacent.
• a zone can comprise several sub-assemblies and several extractor means.
• an area can take the form of a locker.
• a locker within the meaning of the present invention, is meant a portion of the heat exchanger which is materially separable.
• a locker or an area may consist, according to the invention, of one or more layers of a thermally conductive material, of one or more evaporation surfaces, of one or more condensation surfaces and of one or more extractor means.
• thermally conductive material within the meaning of the present invention, is meant a material with the aid of which it is possible to maintain both the phenomenon of evaporation and also of condensation of a liquid to be treated, namely a material whose thermal properties are sufficient under the conditions of implementation of the heat exchanger to transmit, from a condensation surface to the evaporation surface, at least the latent heat of condensation generated per unit area.
• thermally conductive material also having sufficient qualities of resistance to corrosion induced by the liquid to be treated, mention may be made of cast aluminum, cupronickel, stainless steels, titanium, and composite materials of performance of improved thermal conductivity.
• the overall heat transfer coefficient of the heat exchanger is increased.
• the extractor means make it possible to extract at least part of the primary vapor generated by an evaporation surface of a given subset before it moves into a primary vapor space of a subset. - adjacent set.
• the evaporation phenomenon is favored if the vapor atmosphere adjacent to a given evaporation surface is less loaded with saturated vapor.
• the pressure of saturated primary steam in the vicinity of the surfaces of the heat exchanger is reduced either at any point or globally. evaporation.
• the primary steam for example in a conduit independent of the primary steam spaces, one avoids creating pressure drops within said primary steam space, pressure drops which have the effect of reducing in certain places the differential of negative pressure which is necessary for the phenomenon of evaporation.
• the channeling or extraction of the primary steam therefore favors the homogeneity of the negative pressure differentials and tends to eliminate the reduction of this necessary negative differential. This therefore makes it possible not only to increase the overall heat transfer coefficient of the heat exchanger, but also to use the heat exchanger with very low pressure differential and temperature differential, which makes it possible to reduce consumption in energy of the process implementing such a heat exchanger.
• the overall performance increase of the heat exchanger is variable depending on the mode of implementation of the vapor extractor means.
• the extractor means is configured to channel at least part of the primary vapor generated close to an evaporation surface of a subassembly and to evacuate it from the heat exchanger without this primary vapor passing in particular in front of evaporation surfaces of other adjacent subassemblies.
• the more the extractor means is complex and branched the more the performance of the heat exchanger can be increased.
• a balance between the costs of implementing a more or less branched extractor means and the desired performance improvements relating to the heat exchanger must be chosen for each application and by each manufacturer.
• extractor means it is possible to have at least one tube and/or a parallelepipedal chamber which can be formed from two main plates, the tube and/or the chamber being pierced with holes inserted into at least one primary vapor space at the within the volume of the exchanger, or at least one tube, one end of which is used to suck in and extract primary steam within the volume of the exchanger, or any other section pierced with orifices arranged according to a similar principle and which can be of any shape.
• heat exchangers spaced out and of large sizes that is to say having a volume of the order of 1 m 3 or more, for example with horizontal tubes of rows spaced apart by approximately 20 to 30 mm, and/or more compact heat exchangers, for example plate heat exchangers, but of small size, that is to say having a volume less than or equal to 0.5m 3 , make it possible to maintain performance ranging from 3500 W/m 2 .K even up to 6500 W/m 2 .K.
• the heat exchanger according to the invention can be defined by a specific volume lower than those of the heat exchangers currently used and made from materials characterized by lower mechanical strengths than the materials currently used in heat exchangers. Indeed, the materials used in the heat exchanger thermal according to the invention must withstand mechanical stresses lower than those which must withstand the materials used in current heat exchangers.
• the heat exchanger according to the invention can preferably be a thin falling film type heat exchanger.
• the heat exchanger according to the invention may comprise, by way of zones, several compartments of small dimensions.
• the layer thicknesses of a thermally conductive material which were not sufficient on large volumes relative to current heat exchangers are now sufficient according to the invention.
• a greater density of layer of thermally conductive material of smaller thicknesses therefore makes it possible to build sub-assemblies of small dimensions which can be integrated into lockers, which are light and which do not require a support structure other than, for example , side flanges. Said side flanges also making it possible to facilitate the connection between each locker.
• each of the zones can comprise several extractor means.
• each zone may further comprise collector means connected to one or more extractor means of said zone, the collector means being configured to collect the primary vapor extracted by said one or more extractor means from said zone.
• the collector means of one of the zones can preferably be interconnected to the collector means of another of said zones, the interconnected collector means being further connected to a pipe configured to channel the vapor primary collected by the collector means interconnected to the outside of said volume.
• each of said zones may further comprise a means for introducing secondary steam.
• each zone for example of the locker type, it is advantageous for each zone, for example of the locker type, to be autonomous. Accordingly, in this embodiment, each of the zones may preferably further comprise a removal means configured to remove condensate and non-condensable gases.
• each of the layers of a thermally conductive material may comprise an evaporation surface and a condensation surface, the evaporation surface being opposite the condensation surface.
• the layer of a thermally conductive material can be in any form, in particular in the form of a two-dimensional or three-dimensional object.
• two-dimensional object is meant within the meaning of the present invention, an element whose length and width are much greater than the thickness.
• a two-dimensional object can be a film, a sheet, or a plate.
• three-dimensional object is meant within the meaning of the present invention, an object in volume which is not a two-dimensional object.
• a three-dimensional object can be a tube, a sphere, a parallelepiped
• the thickness of said layer of a thermally conductive material is less than 400 ⁇ m, preferably less than 300 ⁇ m, or even preferably less than 200 ⁇ m.
• the thickness of the layer of thermally conductive material can be between 25 ⁇ m and 100 ⁇ m when this material is a noble metal, and can be between 40 ⁇ m and 250 ⁇ m when this material is made of composite plastic.
• the structure of the heat exchanger is advantageously equivalent to that of the heat exchangers currently used. Consequently, in this embodiment, the layer of a thermally conductive material can be in the form of a plate comprising one of the evaporation surfaces and one of the condensation surfaces.
• the layer of a thermally conductive material is in the form of a plate
• large-size heat exchangers with acceptable performance according to the state of the art have a specific exchange surface per volume of the order of 40 to 60m 2 /m 3 while using the plate heat exchanger according to the invention, it is possible to have a much higher specific exchange surface per volume, up to 100m 2 /m 3 , or even 200m 2 /m 3 or even 250m 2 /m 3 .
• two adjacent plates can preferably be separated by a distance d of between 2 mm and 15 mm.
• the extractor means can be found, but not necessarily.
• the distance d can preferably be between 2mm and 7mm.
• Said extractor means can take the form of an extraction chamber whose thickness, namely the distance between the outer walls of the two main plates which constitute it is between 0.5 and 5 mm, the thickness of each of said plates possibly being between 25 and 500 ⁇ m.
• the heat exchanger according to the invention also has several advantages if one works with a low temperature differential applied between the condensation surface and the evaporation surface of the same plate, that is to say a low temperature differential between secondary and primary steam. It should be noted that current heat exchangers typically work with temperature differentials significantly greater than 1°C, often between 2.0 and 2.5°C, or even greater than or equal to approximately 5°C for heat exchangers that do not have a thin falling film.
• the temperature differentials, with saturated steam, are associated according to the laws of physics with pressure differentials, and a temperature differential between 2.0 and 2.5°C corresponds to a compression factor, in the case of a work according to the single-acting MVC, respectively between 1.11 and 1.14.
• the heat exchanger has, for its part, a temperature differential applied between said condensation surface and said evaporation surface of the same plate, comprised between 0.4 and 1.2 °C when the liquid to be treated is sea water, and 0.1 and 0.9 °C when the liquid to be treated is brackish water.
• the ebullioscopic difference is approximately equal to 0.4° C.; if it is desired to operate the evapo-condensation process with a total temperature differential between the condensation surface and the saturated primary steam which is between 0.5°C and 0.7°C for example, the effective temperature differential between the two sides of a layer will therefore be between 0.1°C and 0.3°C.
• a large heat exchanger is operated without extractor means with an effective temperature differential equal to 0.3°C, for example, and the hydraulic head losses on certain paths of the primary vapors are such that they correspond, according to Mollier, to a saturated steam temperature differential of, for example, 0.1 °C or more, the heat exchange capacity of the heat exchanger would be reduced by one third or more , at the places concerned. Thanks to the invention, we can operate heat exchangers large and compact heaters, with an effective temperature differential as low as, for example, 0.1°C, without loss of efficiency.
• the heat exchanger is used with seawater at 35 g/l, a conversion rate of 30 to 40%, an equilibrium temperature, that is to say of primary steam, from 40 to 45°C, an absolute pressure of the enclosure of 0.05 to 0.1 bar, and an effective temperature differential between the two surfaces of evaporation and condensation of a layer of thermally conductive material between 0.1 at 0.3°C, which corresponds to a total temperature differential between the condensation surface and the saturated primary steam of 0.5 to 0.7°C.
• the heat exchanger can be used effectively with effective temperature differentials as low as 0.1 to 0.5°C for any other type of water to be treated whose ebullioscopic difference is different, using the same method of calculation to determine the total temperature differential of each different configuration.
• the heat exchanger is preferably characterized in that the effective temperature differential between the condensation surface and the evaporation surface of a layer of a thermally conductive material can be less than 0.5°C.
• the heat exchanger is advantageous for the heat exchanger to be made up of a number of zones, for example of the compartment type, these compartments being monobloc and self-supporting and comprising layers of thermally conductive materials having very small thicknesses, in particular less than 250 ⁇ m, and very close together, in particular by a distance d of less than 2 to 7 mm. Therefore, in this embodiment, the ratio between the number of zones, which may be lockers, and said volume is between 4 and several thousand.
• self-supporting locker within the meaning of the present invention, is meant an assembly by welding or gluing of layers of thermally conductive materials constituting at least a part of the heat exchanger, or a locker, the assembly holding together alone or using welded or glued side flanges, which can be transported, installed and implemented without deforming or requiring a means of reinforcement or external support.
• these zones have a section of a size smaller than that of an access door to the enclosure of the manhole type, the internal diameter of which is typically 600 to 800 mm.
• This option allows one or two men only, without cumbersome or special tools, and without having to open a whole side of the enclosure, or at least a large part of the latter, to disassemble the heat exchanger and to transport the racks by hand to a maintenance workshop.
• the invention relates to the use of a heat exchanger as described above in a method implementing mechanical vapor compression.
• the mechanical vapor compression may be single-acting.
• FIG 1 schematically represents part of a heat exchanger comprising plates according to one embodiment of the invention
• FIG 2 schematically represents an extractor means included in a heat exchanger according to one embodiment of the invention
• FIG 3 schematically represents part of a heat exchanger comprising tubes according to one embodiment of the invention
• FIG 4 schematically represents an extractor means included in a heat exchanger according to one embodiment of the invention
• FIG 5 schematically represents part of a heat exchanger according to one embodiment of the invention.
• FIG 6A and FIG 6B schematically represent sections of a heat exchanger according to one embodiment of the invention
• FIG 7 represents a heat exchanger according to one embodiment of the invention.
• FIG 8 illustrates a heat exchanger according to one embodiment of the invention which implements materially separable subassemblies of the locker type
• FIG 9A], [Fig 9B] and [Fig 9C] represent views of a subassembly of a simplified locker and its compatibility in a heat exchanger according to one embodiment of the invention
• FIG 10 schematically represents part of a heat exchanger comprising inclined plates according to one embodiment of the invention
• FIG 11 A schematically represents a heat exchanger comprising an assembly of racks according to one embodiment of the invention
• FIG 11 B schematically represents a heat exchanger comprising tubes according to one embodiment of the invention.
• FIG 12 represents part of a heat exchanger comprising plates according to the state of the art.
• FIG 13 represents part of a heat exchanger comprising tubes according to the state of the art.
• the following description presents at least parts of heat exchangers, evaporator-condenser type, produced according to the invention and comprising several zones.
• the heat exchanger is configured to desalinate seawater.
• Each zone is either a virtual division or a physically separable compartment of the heat exchanger and is made up of several elements of the heat exchanger.
• the heat exchanger is delimited by its volume Vec. Some of the zones or compartments can for example be stacked on top of each other.
• the heat exchanger is made up of several sub-assemblies which are each partly made up of a layer of a thermally conductive material.
• This layer of a thermally conductive material comprises an evaporation surface configured to generate, in a vapor space to be evaporated or primary vapor space, a primary vapor from seawater, and a condensation surface configured to condense , in a vapor space to be condensed or secondary vapor space, a secondary vapor into condensate and to generate a latent heat of condensation, the secondary vapor being the vapor to be condensed.
• each subassembly consists in part of a layer of a thermally conductive material having a thickness of less than 400 ⁇ m, for example titanium, duplex or superduplex steel or equivalent, or composite plastic material of thermal performance improved.
• each evaporation surface is opposite each condensation surface.
• the thermally conductive material is configured to transfer at least part of the heat condensation latent from the condensation surface to the evaporation surface of a given subset.
• the heat exchanger further comprises an upper part through which the seawater is introduced.
• the seawater to be desalinated is distributed over the upper part of the heat exchanger and percolates by gravity over all the surfaces. evaporation of the sub-assemblies.
• the sea water which percolates by gravity in the lower part of the first sub-assembly sprinkles the upper part of the surfaces to be wetted in the second sub-assembly, and so on for the other possible sub-assemblies, until reaching at the very bottom of the heat exchanger in order to constitute the concentrate.
• the invention relates to all possible configurations of heat exchangers, but in order to present an intelligible description, the following examples focus on heat exchangers employing thermally conductive materials in the form of plates or in the form of a bundle of tubes.
• the following examples illustrate configurations with vertical plates or horizontal tubes, with condensation inside the chambers or tubes, but the invention can be implemented with any type of configuration. In some configurations, the plates may or may not be parallel.
• FIG. 1 illustrates part of a vertical plate heat exchanger. Specifically, each of the vertical plates represents a first part of the heat exchanger. Each of these first parts represents an evapo-condensation chamber 100 in continuous lines. Each evapo-condensation chamber 100 notably comprises a thermally conductive material as well as an evaporation surface and a condensation surface. Each of these evapo-condensation chambers 100 in particular also comprises a primary vapor space located on the side of the evaporation surface and a secondary vapor space located on the side of the condensation surface. On the side of the evaporation surface is therefore generated the primary vapor.
• each of these extraction chambers 200 comprises at least one extractor means 210 which is represented as being a rectangular parallelepiped comprising in particular two large faces, in particular two main plates, each pierced with a network of holes 220 , the extractor means 210 being inserted into at least one primary vapor space within the volume of the exchanger.
• the distance d between an evapo-condensation chamber 100 and an adjacent extraction chamber 200 is between 2 mm and 7 mm.
• the thickness of an extraction chamber 200, or more precisely the distance which separates the outer ends of the two main plates which constitute it, is between 0.5 and 10 mm; the thickness of said two main plates being between 25 ⁇ m and 500 ⁇ m.
• the extraction chamber 200 is located between two evaporation surfaces of two adjacent sub-assemblies, and is connected to a suction means which can also be connected to a system of ducts representing a network suction of primary steam.
• This extraction chamber 200 in dotted line constitutes the second part of the heat exchanger. It should be noted that each of the extraction chambers 200 is shown in dotted lines in the figures for the sole purpose of visually differentiating them from the evapo-condensation chambers 100.
• each primary vapor extraction chamber 200 is installed between two evapo-condensation chambers 100. Using the extraction chamber 200, at least part of this vapor primary is then channeled, i.e. collected and directed to other elements to be further processed (for example a recompression in the case of MVC, or a transfer to a next effect or stage in the case of MED or multi-effect MVC).
• a means of introducing secondary steam ensures the delivery of secondary steam inside each of the evapo-condensation chambers 100, in particular in its condensation space.
• the primary steam generated is channeled and extracted out of the heat exchanger without passing through the evaporation surfaces of other zones.
• each smaller zone in FIG. 1 is defined by a virtual division into rectangular parallelepipeds of the exchanger.
• Each smaller zone comprises a single hole drilled in an extraction chamber 200, a part of the adjacent evapo-condensation chamber 100, and the volumes necessary around these chambers in order to register the virtual cutting in a continuous network.
• said smaller zone indeed comprises at least one layer of heat-conducting material, an evaporation face and a primary vapor space, a condensation face and a secondary vapor space, an extractor means consisting of said single hole pierced, and a pipe (consisting of the extraction chamber which is itself connected to a collector means) which extracts the primary vapor from the exchanger.
• each of the zones can comprise several extractor means.
• each zone can also further comprise a collector means connected to one or more extractor means of the zone.
• the collector means is configured to collect the primary vapor extracted by said one or more extractor means from the zone.
• the collector means of one of said zones is interconnected to the collector means of another of said zones.
• the interconnected collector means are also connected to a pipe configured to channel the primary steam collected by the interconnected collector means to the outside of the volume defining the heat exchanger, that is to say outside the delimited interior volume by the outer walls of the heat exchanger.
• each of the zones further comprises a withdrawal means configured to withdraw condensate and non-condensable gases.
• Each of the zones as defined further comprises a means of extracting the primary vapor to ensure its transport to the extractor means of one or more other zones.
• the primary vapors are channeled locally and routed to the outside of the heat exchanger.
• Figures 3 and 4 illustrate another implementation of the same principle with evapo-condensation chambers 100 in the form of tubes rather than in the form of plates as illustrated in Figures 1 and 2.
• the primary vapor extractor means can be constructed as an assembly of tubes which take a direction or the same direction as that of the columns 300 of tubes of the heat exchanger.
• the tube assembly is connected to a manifold means in the same manner as the 200 vapor extraction chambers.
• protections preventing the liquid to be treated to wet the extracting means can take the form of profiles, for example of V-section open downwards, installed above each extraction chamber 200, so that said profiles return the sprinkled water to the thermally conductive layers of the heat exchanger.
• Figure 5 illustrates an assembly of the heat exchanger 400 according to Figure 1, provided with side flanges (a left flange 410 and a right flange 420).
• the assembly is made of two parts.
• the first part is a successive stack of several glued or welded assemblies, each composed of a layer of a thermally conductive material, then of a spacer closing the condensation space, then of a second layer of a thermally conductive material. conductor, then a spacer closing the primary vapor space and provided with an extraction chamber 200.
• the second part comprises: a means for collecting the primary vapor, a means for introducing the secondary vapor, a means removal of condensate and non-condensable gases. If we observe the longitudinal section of a spacer closing the condensation space (FIG.
• Figure 7 illustrates a variation of the exchanger according to the example shown in Figure 5 where the evapo-condensation chambers 100 are tubular as shown in Figures 3 and 4.
• FIG. 8 illustrates another embodiment of the invention which implements materially separable zones or compartments 500.
• the heat exchanger presented is of the same size, of the same exchange capacity, and of the same volume as that of FIG. 5.
• the heat exchanger of FIG. 8 consists of several bins 500 (36 in our example) which are materially separate and stackable.
• the racks 500 may also themselves be made up, or not, of a large number of sub-zones.
• the compartments 500 can also be made identically to a heat exchanger according to FIG. 5 of reduced size.
• Each locker 500 is provided with its own primary vapor sub-collector which is preferably connected to each extractor means of the other lockers.
• Each rack 500 may also include a set of ducts which may be its own sub-means for introducing secondary steam, which may be the right flange 420, and for removing condensate and non-condensable gases which may be the left 410 .
• the sub-means of the lockers 500 are, in an optimized embodiment, interconnected in their upper and lower parts of the stacks to form ducts 510 and 520 which are themselves connected to the main collectors 550 of vapors, distillate and non-condensable gases of the heat exchanger.
• Each of the ducts 510 and 520 is formed by a vertical or horizontal assembly respectively of the left flanges 410, and of the right flanges 420.
• the ducts 510 are primary steam, condensate and non-condensable gas extraction ducts.
• Ducts 520 are secondary steam supply ducts.
• FIG. 9A which is a perspective view of a locker 500 does not show the evapo-condensation chambers 100 to facilitate reading.
• FIG. 9A shows the left flange 410 of a simplified locker, where the primary steam extractor means is reduced to a network 430 of slots or orifices drilled in the left flange 410 adapted to collect the primary steam, without it is necessary that an extraction chamber 200 be present between each evapo-condensation chamber 100 as illustrated in figure 1.
• Figures 9B and 9C show horizontal sections of the simplified rack of Figure 9A. They show that this simplified configuration is advantageously compatible with an assembly of evapo-condensation chambers 100 with plates whose sections increase on the path of the primary steam and decrease on the path of the secondary steam.
• Figure 10 shows an example of implementation of the invention for an assembly of inclined evapo-condensation plates, where only one face of the resulting evapo-condensation chambers 100 is thermally active. Indeed, in this configuration, it is the evapo-condensation chamber 100 adjacent to that considered which forms the extraction chamber 200 of the primary steam.
• Figure 11A shows a simplified rack assembly; this representation clearly shows the networks 430 of slots (dotted, appearing darker) of primary steam inserted within the heat exchanger.
• the networks 430 of slots are, for example, directly linked to the extraction ducts 510, formed by the interlocking of the flanges of the compartments.
• FIG 11B illustrates a horizontal tube bundle heat exchanger, in which only a few vapor extractor means have been placed (dotted, appearing darker) within it.
• This heat exchanger according to a particular mode of the invention, consists of several virtual zones, each zone comprising at least one hole for extracting vapor collected and extracted from the volume of the heat exchanger.
• This example shows a partial implementation of the invention by installing only a few primary vapor collectors or extractor means within the heat exchanger, with the aim of improving the performance only partially but at a lower cost.

Landscapes

• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Thermal Sciences (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Life Sciences & Earth Sciences (AREA)
• Dispersion Chemistry (AREA)
• Hydrology & Water Resources (AREA)
• Environmental & Geological Engineering (AREA)
• Water Supply & Treatment (AREA)
• Organic Chemistry (AREA)
• Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
• Containers, Films, And Cooling For Superconductive Devices (AREA)
• Separation By Low-Temperature Treatments (AREA)
• Beverage Vending Machines With Cups, And Gas Or Electricity Vending Machines (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=76217605

Family Applications (1)

Country Status (6)

Family Cites Families (5)

• 2021
  • 2021-05-25 BE BE20215420A patent/BE1029506B1/fr active IP Right Grant
• 2022
  • 2022-05-24 WO PCT/EP2022/063959 patent/WO2022248425A1/fr active Application Filing
  • 2022-05-24 CN CN202280042100.3A patent/CN117479987A/zh active Pending
  • 2022-05-24 EP EP22730436.7A patent/EP4347076A1/de active Pending
  • 2022-05-24 IL IL308817A patent/IL308817A/en unknown
  • 2022-05-24 AU AU2022282500A patent/AU2022282500A1/en active Pending

Also Published As

Similar Documents

Legal Events