FR3069918A1 - HEAT EXCHANGER COMPRISING A MULTI-CHANNEL DISTRIBUTION ELEMENT - Google Patents

Abstract

The invention relates to a distribution element (22) configured to be arranged in at least one distribution zone (20) of a plate and fin type heat exchanger (1), said distribution element (22) comprising a a plurality of separator walls (25) arranged so that, when the dispensing member is arranged in a dispensing zone (20), said dispensing zone (20) is divided into a plurality of channels (26) for the flow fluid (F1). According to the invention, said channels (26) define flow paths of different lengths and have variable fluid passage sections along said flow path.

Description

The present invention relates to a distribution element configured to be arranged in a distribution zone of a heat exchanger of the plate and fin type, as well as an exchanger comprising such a distribution element and at least one set of passages for a fluid to be put in heat exchange relationship with at least one other fluid. The element according to the invention allows a more homogeneous distribution of the fluid over the width of said passages.

The present invention finds particular application in the field of gas separation by cryogenics, in particular air separation by cryogenics (known by the acronym "ASU" for air separation unit) used for the production of gaseous oxygen under pressure. In particular, the present invention can be applied to a heat exchanger which vaporizes a liquid flow, for example oxygen, nitrogen and / or argon by heat exchange with a gas.

The present invention can also be applied to a heat exchanger which vaporizes at least one flow of liquid-gas mixture, in particular a flow of mixture with several constituents, for example a mixture of hydrocarbons, by heat exchange with at least another fluid, for example natural gas.

The technology commonly used for an exchanger is that of aluminum exchangers with brazed plates and fins, which make it possible to obtain very compact devices offering a large exchange surface.

These exchangers include plates between which heat exchange waves are inserted, formed by a succession of fins or wave legs, thus constituting a stack of passages for the various fluids to be put into heat exchange relationship.

These passages include so-called distribution zones arranged, following the overall direction of flow of the fluid in the passage in question, upstream and downstream of the heat exchange zone proper. The distribution zones are fluidly connected to semi-tubular collectors configured to distribute the different fluids selectively in the different passages, as well as to evacuate said fluids from said passages.

In known manner, these distribution zones generally comprise distribution waves, arranged in the form of corrugated sheets between two successive plates. Distribution waves are generally perforated straight waves cut in the shape of triangles or trapezoids. They divert the fluid from the exchanger inlet manifold in order to distribute it over the width of the heat exchange zones, as well as the recovery of the fluid from said heat exchange zone. Distribution waves also act as spacers to provide mechanical resistance to brazing and in operation of the passage distribution area.

One of the problems with the configuration of current distribution zones is the poor distribution of fluids in the direction of the heat exchange zones. In fact, the distribution zones are occupied by at least two wave mats in order to optimize the falls of the shape cuts, thereby increasing the risk of play between the mats. The assembly of the wave mats can also cause accidents along the fluid flow path, which contributes to increasing the pressure losses in the distribution areas. Due to these imperfections in the distribution zones, variations in flow rate of an amplitude of the order of 10% can occur, which are detrimental to the proper functioning of the exchanger.

Similarly, distribution faults are observed in the distribution zones dedicated to the recovery of fluids from the heat exchange zones.

Another problem concerns the mechanical strength of the distribution zones. Indeed, these zones are provided with waves of lower densities, typically between 6 and 10 legs per inch, than those of the heat exchange zones. At present, the distribution zone of a passage typically extends over a length, measured in a longitudinal direction corresponding to the direction of flow of the fluid in the heat exchange zone of the same passage, from the 'of the order of 200 to 600 mm, and over a width, measured perpendicular to said longitudinal direction, of the order of 500 to 1500 mm. Since the distribution zones constitute parts of less good mechanical strength than the heat exchange zones, it is desirable to limit their longitudinal extent as much as possible to guarantee better resistance of the exchanger during the circulation of fluids at high pressure. within the passages.

The object of the present invention is to solve all or part of the problems mentioned above, in particular to provide a heat exchanger in which the distribution of the fluid (s) in the heat exchange zones is as uniform as possible, and which also has smaller footprint distribution areas than in the prior art.

The solution according to the invention is then a dispensing element according to claim 1.

Depending on the case, the element of the invention may include one or more of the following technical characteristics: see claims 2 and following.

In addition, the invention relates to a heat exchanger comprising a distribution element according to the invention.

The present invention will now be better understood thanks to the description which follows, given solely by way of nonlimiting example and made with reference to the attached diagrams, among which:

Figure 1 is a schematic three-dimensional view of a plate and fin type exchanger;

Figure 2 is a partial schematic view, in longitudinal section of a distribution area according to an embodiment of the invention;

Figures 3A, 3B and 4 are partial schematic views, in longitudinal section of distribution areas according to other embodiments of the invention;

Figures 5A and 5B are schematic views, in longitudinal and three-dimensional section respectively, of a distribution area according to another embodiment of the invention;

Figures 6A, 6B, 6C and 7 present results of simulations carried out with a distribution element as shown schematically in Figure 5B.

As seen in FIG. 1, a heat exchanger 1 of the plate and fin type comprises a stack of plates 2 which extend in two dimensions, length and width, respectively in the longitudinal direction z and the lateral direction y. The plates 2 are arranged parallel one above the other with spacing and thus form several sets of passages 3, 4, 5 for fluids F1, F2, F3 to be put into indirect heat exchange relationship via the plates 2. The lateral direction y is orthogonal to the longitudinal direction z and parallel to the plates 2. Preferably, the longitudinal axis is vertical when the exchanger 1 is in operation.

Preferably, each passage has a parallelepipedal and flat shape. The passages extend in length along the longitudinal direction z and in width along the lateral direction y. The gap between two successive plates is small compared to the length and width of each successive plate.

Each passage 3, 4, 5 is divided, in the longitudinal direction z, into at least one distribution zone 20 and a heat exchange zone 21. The flow of fluids within the distribution zones takes place generally parallel to the longitudinal direction z. The heat distribution and exchange zones 20, 21 are preferably juxtaposed along the longitudinal axis z.

According to the representation of Figure 1, considering in particular the passage 3 whose internal part is made visible, two distribution zones 20 are arranged on either side of the heat exchange zone 21, one serving to bring the fluid F1 to the heat exchange zone 21, the other to evacuate from said zone.

In a manner known per se, the exchanger 1 comprises manifolds of semi-tubular shape 7, 9 provided with openings 10 for the introduction of the fluids into the exchanger 1 and the evacuation of the fluids from the exchanger 1. These collectors have narrower openings than the passages. The distribution zones 20 serve to distribute the fluids introduced through the openings of the collectors over the entire width of the passages.

According to the invention, a distribution element is arranged in at least one distribution zone 20 of a passage 3 of the exchanger, this element comprising a plurality of separating walls 25 arranged so as to divide said distribution zone 20 into a plurality of channels 26 for the flow of the fluid F1. Said channels 26 define flow paths of different lengths and have variable fluid passage sections along said flow paths.

Dividing the distribution area into several separate channels of varying lengths and sections allows the fluid to be diverted while finely controlling the conditions of flow of the fluid within each channel. In particular, it is possible to rebalance the velocities of the fluid flowing in the different channels, so as to obtain substantially identical fluid velocities at the outlet of each channel, and from there a uniform or almost uniform distribution of the fluid over the width of the passages at the outlet of the distribution area, while minimizing pressure drops in the distribution area.

In addition, the distribution element provides structural rigidity to the exchanger distribution area since the spacer function can be provided by the separating walls.

It should be noted that by “fluid passage section” is meant the surface through which the fluid flows within the channel, this being measured in a plane perpendicular to the direction of movement of the fluid F1 in said channel, i. e. perpendicular to the current lines of the moving fluid F1.

The length of the flow paths means the distance to be traveled for the fluid F1 between the inlet and the outlet of the channel in question.

Preferably, a distribution element according to the invention is housed in several, if not all, of the distribution zones of one or more sets of passages of the exchanger. Said element extends over almost all, or even all, of the height of the passages, measured in the vertical direction x, so that the structure is advantageously in contact with each plate 2 forming the passage 20.

The channels are preferably fluidly isolated from each other. The flow parameters of each channel are thus controlled independently of those of the neighboring channels, which makes it possible to precisely adjust the distribution of the fluid over the width of the passages at the outlet of the distribution zone. Advantageously, the separating walls 25 are erected perpendicular to the plates 2.

Preferably, the number of channels 26 is at least 6, more preferably between 5 and 50. Indeed, the number of channels 26 must, on the one hand, be sufficient to give the element 22 its rigidity mechanical and, on the other hand, not to be excessive in order to leave free a sufficient volume for the flow of the fluid and to limit the pressure losses.

Advantageously, the distribution element 22 comprises a first end 23 forming an inlet or an outlet for the fluid F1 and a second end 24 in fluid communication with the heat exchange zone 21.

More specifically, as visible in Figure 1, the passages 3 to 5 are bordered by closure bars 6 which do not completely close the passages but leave free openings 23, 24 for the entry or exit of the corresponding fluids.

Figure 2 partially shows the "inlet" part of a passage 3 of an exchanger according to an embodiment of the invention. A fluid manifold 7 is arranged in the left corner of the exchanger, the first end 23 being fluidly connected to the manifold 7 and forming an inlet for the fluid F1, the flow of which is shown diagrammatically by dashed arrows.

The first and second ends 23, 24 preferably extend in a plane parallel to the lateral direction y and perpendicular to the longitudinal direction z. The separating walls 25 extend between the first and second ends 23, 24 and form channels 26 opening out at the second end 24 and configured to distribute uniformly, in the lateral direction y, the fluid F1 so as to obtain a distribution homogeneous or almost homogeneous towards or from the entire width of the heat exchange zone 21 when the other of said first and second ends 23, 24 is supplied with fluid F1.

Advantageously, each channel is provided with first openings 26a and second openings 26b. Advantageously, as shown diagrammatically in FIG. 2, the first and second openings 26a, 26b are situated at the level of the first and second ends 23, 24 respectively, the separating walls 25 extending continuously from the first end 23 to the second end 24. The flow path of the fluid F1 corresponds to the path to be traveled between the openings 26a and 26b. Each of the ends 23, 24 can thus be divided into a series of openings 26a and a series of openings 26b respectively.

The openings 26a, 26b of the channels 26 may have identical or variable fluid passage sections depending on the channels 26 considered. The fluid passage sections of the openings 26a and 26b correspond to the internal surfaces of the channels 26 measured at the first and second ends 23, 24 in a plane parallel to the lateral direction y.

Preferably, at least one first opening 26a has a fluid passage section different from the fluid passage section of another first opening 26a and / or at least a second opening 26b has a fluid passage section different from the fluid passage section of another second opening 26b.

Advantageously, the first openings 26a and / or the second openings 26b of the same channel 26 have fluid passage sections that are larger than the flow path defined by said channel 26 is long, i. e. that the distance to be traveled for the fluid F1 between the first opening 26a and the second opening 26b is large.

Thus, in the example of Figures 3A, 3B or 5B where the first end 23 is arranged at an extreme edge of the element 22 along the direction y, the first end 23 is subdivided into a first series of first openings 26a having increasing fluid passage sections in the lateral direction y. This favors the supply of the channels configured to distribute the fluid F1 from the manifold 7 to the part of the second end 23 diagonally opposite to said end edge.

According to another example (FIG. 5A) in which the element 22 has a median plane M and the first end 23 is centered relative to the plane M, the first openings 26a arranged, preferably symmetrically, on either side of plane M have increasing fluid passage sections as one moves away from said median plane M.

This compensates for the natural tendency of the fluid to pass through the region of the distribution zone located opposite the collector rather than through the zones further from the collector, and thus homogenize the distribution of the fluid across the width of the passage 3 of the exchanger.

Advantageously, when the distribution element 22 is disposed in the distribution zone 20 of an exchanger, the first end 23 is located on the side of the inlet manifold 7 of the exchanger and forms an inlet for the fluid F1. The first openings 26a of the first end 23 have fluid passage sections which vary according to their position along the lateral direction y.

Thanks to the use of openings 26a of different passage sections, it is in particular possible to overfeed channels which are less conducive to the passage of the fluid, and this as soon as the fluid F1 enters the distribution zone 20, which generates less pressure losses and therefore leads to a more efficient fluid distribution system.

According to an advantageous embodiment of the invention, all or part of the channels 26 comprise means 28 for modifying the linear resistance to flow of said channels 26. The linear resistance to flow of each channel can thus be adjusted according to the desired flow characteristics in each channel 26, in particular flow rate and fluid speed. Thus, the linear resistance to flow of the channels can be adjusted so that each channel 26 has a similar overall resistance to flow. The characteristics of the fluid leaving the channels 26 are thus homogenized in the lateral direction y, which allows uniform distribution to or from the heat exchange zone 21.

By “resistance to flow” is meant the ability of the channel to generate viscous friction on the one hand and on the other hand to deflect the flow (pressure force normal to the wall). This resistance is expressed in the form of a reaction force of the solid structure on the flow in Newton, which results in the fluid by a pressure drop in Pascals. This force depends on the first order of the kinetic energy of the fluid (rho * u ² ) and on the second order of the Reynolds number (rho * u * D / mu). The resistance to linear flow corresponds to the resistance to flow of the channel expressed per unit of length.

Advantageously, a channel 26 will include modification means 28 configured to produce an increase in the linear resistance to flow all the greater as the opening 26a of said channel is close, in terms of distance to be traveled for the fluid F1, from the other opening 26b. For example, in the configuration illustrated in FIG. 3B, the channels 26 include modification means 28 configured to produce an increasingly weak increase in the linear resistance to flow in the lateral direction y. Indeed, this makes it possible to compensate for the natural preferential passage of the fluid in the axis rather than through the side of the exchanger, and therefore to obtain a good distribution of the fluid. In the case where the manifold 7 is centered relative to the median plane M of the exchanger, as shown in FIG. 5A, the resistance to the fluid of a channel will be all the greater the closer it is to the median plane. Mr.

The channels 26 may have internal profiles shaped to produce variations in resistance to flow.

It is also possible to arrange, within one or more channels 26, obstacles 28 producing different flow resistances. The insertion of a porous structure 28, for example a metallic foam, within a channel will increase its resistance to flow. We can thus adjust the linear resistance to the flow of the channels 26, by varying the characteristics of the structures 28 inserted, such as volume, density, etc. depending on the channels. In the example illustrated in FIG. 3B, the volume occupied by the porous structures 28 decreases in the lateral direction y, so as to produce smaller variations in linear resistance to flow along y.

According to the example shown diagrammatically in FIG. 4, partitions 28 can be arranged in one or more channels 26 so as to create an additional stage for dividing the distribution zone 22. This makes it possible to vary the linear resistance to flow as well as controlling even more finely the flow parameters of the fluid distributed to or recovered from the heat exchange zone 21. The use of additional partitions 28 is particularly advantageous when the first end 23 of the distribution element has a width too small to be able to be divided into a sufficient number of channels 26.

Depending on the case, the dividing walls 25 and / or the partitions 28 may have, in longitudinal section, rectilinear profiles, as illustrated in FIGS. 2 and 4, or curvilinear, as illustrated in FIGS. 3A, 3B and 5A, 5B .

According to a particularly advantageous embodiment, the separating walls 25 have predetermined curvilinear profiles comprising at least one inflection point P.

Such a geometry makes it possible to deflect the fluid more quickly, that is to say over a shorter distance L1, and this over a large width of the passage of the exchanger. It is thus possible to reduce the longitudinal extent of the distribution zone 20, and consequently to increase the mechanical strength of the exchanger since the compactness of the so-called "weak" zone of the exchanger is increased.

This also offers the possibility of reducing the width of the first end 23 of the distribution element 22, and therefore the width of the manifold 7, which is a relatively expensive piece. Preferably, the first end 23 forming an inlet or outlet of the distribution element 22 has, in the lateral direction y, a width L3 of between 50 and 1000 mm, more preferably between 100 and 500 mm.

Such profiles also make it possible to reduce the pressure drops within the channels 26, the sudden changes in channel profiles being known to generate recirculations of fluids causing pressure drops.

Preferably, the distribution element 22 has, parallel to the longitudinal direction z, a length L1 of less than 500 mm, preferably between 50 and 200 mm, more preferably between 80 and 100 mm. Preferably, the length L1 of the distribution element 22 represents less than 20% of the length of the exchange zone 21. The distribution element 22 has, parallel to the lateral direction y, a width L2, the ratio between a length L1 and the width L2 being less than 20%, preferably between 5 and 10%. The width L2 is preferably between 500 and 1500 mm.

As seen in Figure 5B, illustrating a dispensing element 22 according to an embodiment of the invention, this may include a support configured to hold the walls 25 integral with each other. For example, said support may include a bottom 27, preferably a planar bottom which can be formed from a flat sheet, from which the separating walls 25 are erected. The walls 25 are preferably erected in the vertical direction x. The walls 25 can have heights h typically between 2 and 15 mm. Preferably, the heights are chosen so that the walls 25 extend in almost all, if not all, of the height of the passage in the vertical direction x.

The distribution element 22 is advantageously formed from a metallic material, preferably aluminum or an aluminum alloy. The element can be formed in particular from a porous material, preferably with non-opening pores, for example a metallic foam.

Preferably, the distribution element 22 is monolithic, which makes it possible to minimize accidents along the fluid flow paths.

The element 22 can be manufactured by an additive manufacturing method, preferably by thermal spraying, which allows parts of complex geometries to be produced in a single block. In particular, it is possible to use a cold spraying process called "cold spray".

Note that the additive manufacturing process can also be designated by the terms "3D printing" or "three-dimensional printing". Additive manufacturing makes it possible to produce a real object, using a specific printer which deposits and / or solidifies the material, layer by layer, to obtain the final part. The stacking of these layers creates a volume.

Element 22 can also be manufactured by the following additive manufacturing processes:

- the FDM process (acronym for “Fuse Deposition Modeling”), which consists of modeling by depositing molten material),

- stereolithography (SLA), a process in which ultraviolet radiation solidifies a layer of liquid plastic, or

- selective laser sintering, in which a laser agglomerates a layer of powder.

Alternatively, the distribution element 22 can be manufactured by foundry. This manufacturing process makes it possible to produce parts with complex geometries at a relatively low cost compared to additive manufacturing. Preferably, the element 22 is formed from an aluminum alloy for foundry, that is to say an alloy of which the main constituent is aluminum, of density lower than intended to be transformed by techniques of foundry.

As regards the heat exchange zones 21 of the exchanger, these advantageously comprise heat exchange structures 8 arranged between the plates 2, as shown in FIG. 1. These structures have the function of increasing the surface area d 'heat exchange of the exchanger and play the role of spacers between the plates 2, in particular during assembly by brazing the exchanger, to avoid any deformation of the plates during the use of pressurized fluids.

Preferably, these structures include heat exchange waves 8 which advantageously extend along the width and the length of the passages of the exchanger, parallel to the plates 2. These waves 8 can be formed in the form of corrugated sheets. In this case, the wave legs which connect the vertices and the successive bases of the wave are called "fins". The exchange structures 8 can also take other particular forms defined according to the desired fluid flow characteristics. More generally, the term "fins" covers blades or other secondary heat exchange surfaces, which extend from the primary heat exchange surfaces, that is to say the plates of the exchanger, in the exchanger passages.

Within a passage, the distribution element 22 according to the invention and the heat exchange structure 8 are preferably juxtaposed along the longitudinal axis z, that is to say positioned end to end. It being noted that a slight clearance may exist between these elements, in order not to block the channels of the exchange zone 21 which are opposite the walls 25 of the channels of the distribution zone 22. Preferably, the first end 23 of element 22 is arranged end-to-end with at least part of the manifold 7 while the second end 24 is arranged end-to-end with at least part of the structure 8. Preferably, the structure 8 , the manifold 7 and / or the element 22 are linked by brazing to the plates 2 and are indirectly linked to each other via their respective connections with the plates 2.

In order to show the effectiveness of a distribution element 22 according to the invention for uniformly distributing the fluid, simulations of fluid flow have been carried out with a distribution element according to FIG. 5B.

The dimensional characteristics of the distribution element 22 were as follows:

- length L1 of element 22: 85 mm,

- half-width L2 / 2 of the element 22: 485 mm,

- width L3 of the first end 23 forming an inlet: 370mm,

-mechanical clearance between the distribution element 22 and the heat exchange structure 8: 2 mm,

- height of the element 22: 9.5 mm (the walls 25 having a height, in the vertical direction x of 7.5 mm and the bottom 27 having a thickness of 2 mm),

- wall thickness 25: 2.3 mm.

With regard to the fluid, the simulation parameters were as follows:

- nature of the fluid: nitrogen,

- fluid pressure at the outlet of the distribution element 22: 1.2 bar,

- temperature of the fluid at the inlet of the collector 7: - 80 ° C,

-temperature of the fluid at the outlet of the collector 9: 17 ° C,

- mass flow rate of fluid circulating in the exchanger passage: 100kg / h.

The results of these simulations are presented in Figures 6A, 6B, 6C and 7. Figures 6A, 6B and 6C represent the maps of the velocities, pressures and temperatures of the fluid flowing within the channels 26 of the distribution element 22. There is a quasi-homogeneous distribution of the fluid leaving the channels 26. FIG. 7 indicates the evolution of the so-called axial velocity values (“axial velocity”), that is to say along the longitudinal direction z, obtained at the output of element 22, as a function of the position in the lateral direction y. We thus start from the center of the distribution element 22 (position at 0 mm) to the edge of the second end 23 (position at 485 mm). The distribution of speed values along the lateral direction y is characterized by a standard deviation (or standard deviation) of 0.9% and a maximum deviation of 2.8% compared to the average value of speed in the area d 'exchange, which is much lower than the variations observed with conventional distribution elements for which the standard deviations are of the order of 3%. Thanks to the invention, the speed variations in the lateral direction at the outlet of the distribution zone are therefore reduced, which makes it possible to distribute the fluid as homogeneously as possible over the entire width of the exchange zone of heat.

Of course, the invention is not limited to the specific examples described and illustrated in the present application. Other variants or embodiments within the reach of the skilled person can also be envisaged without departing from the scope of the invention. By way of example, other directions and directions of flow of the fluids in the exchanger are of course conceivable, without departing from the scope of the present invention. A distribution element according to the invention can thus be arranged in any distribution zone of the exchanger, in one or more series of passage 3, 4, 5 of the exchanger, upstream and / or downstream of one or more several of the exchanger manifolds. For example, Figure 5B illustrates the case where an exchanger passage comprises two distribution elements according to the invention arranged on either side of the heat exchange zone 21 (shown diagrammatically with a deliberately shortened length). It should also be noted that passages 3, 4, 5 of the exchanger can just as well be formed between two successive plates 2 as between a closing bar 6 of the exchanger and a plate 2 immediately adjacent.

Claims (17)

1. Distribution element (22) configured to be arranged in at least one distribution zone (20) of a heat exchanger (1) of the plate and fin type, said distribution element (22) comprising a plurality of walls dividers (25) arranged so that when the distribution element is arranged in a distribution zone (20), said distribution zone (20) is divided into a plurality of channels (26) for the flow of the fluid ( F1), said channels (26) defining flow paths of different lengths and having variable fluid passage sections along said flow paths. 2. Element according to claim 1, characterized in that it comprises a first end (23) forming an inlet or an outlet for the fluid (F1) and a second end (24) in fluid communication with the exchange zone of heat (21) when the distribution element is arranged in a distribution zone (20), each separating wall (25) being formed in one piece and extending continuously from the first end (23) to at the second end (24). 3. Element according to claim 2, characterized in that each channel (26) is provided with a first opening (26a) and a second opening (26b) located at the first and second ends (23, 24) respectively. 4. Element according to claim 3, characterized in that at least one first opening (26a) has a fluid passage section different from the fluid passage section of another first opening (26a) and / or at least a second opening (26b) has a fluid passage section different from the fluid passage section of another second opening (26b). 5. Element according to claim 4, characterized in that the first openings (26a) and / or the second openings (26b) of the same channel (26) have fluid passage sections that are larger than the path flow defined by said channel (26) is long. 6. Element according to one of the preceding claims, characterized in that one or more channels (26) comprise means (28) for modifying the linear resistance to the flow of said channels (26). 7. Element according to claim 6, characterized in that said means (28) comprise a conformation of the interior profiles of said channels (26). 8. Element according to one of claims 6 or 7, characterized in that said means (28) comprise partitions (28) arranged within said channels (26). 9. Element according to one of claims 6 to 8, characterized in that said means (28) comprise porous structures, for example metallic foams, arranged within said channels (26). 10. Element according to one of the preceding claims, characterized in that the separating walls (25) have, in longitudinal section, rectilinear profiles. 11. Element according to one of claims 1 to 7, characterized in that the separating walls (25) have, in longitudinal section, predetermined curvilinear profiles. 12. Element according to claim 11, characterized in that said predetermined curvilinear profiles comprise at least one inflection point (P). 13. Element according to one of the preceding claims, characterized in that the distribution element (22) extends over a length (L1) in a longitudinal direction (z) and over a width (L2) in a lateral direction (Y), the ratio between a length (L1) and the width (L2) being less than 20%, preferably between 5 and 10%. 14. Element according to one of the preceding claims, characterized in that the height (H) of the distribution element (22) extends over a length (L1) of less than 500 mm, preferably between 50 and 200 mm. 15. Element according to one of the preceding claims, characterized in that the distribution element (22) comprises a support (27) by means of which the separating walls (25) are held integral with one another. 16. Element according to one of the preceding claims, characterized in that the distribution element (22) is a monolithic element, preferably manufactured by an additive manufacturing method or by foundry. 17. Heat exchanger (1) of the plate and fin type comprising: - a plurality of plates (2) arranged parallel to each other so as to define at least one set of passages (3) for the flow of a fluid (F 1) intended to exchange heat with at least one other fluid ( F2), the passages (3) extending in a longitudinal direction (z) and a lateral direction (x) perpendicular to said longitudinal direction (z), - each passage (3) being divided, in the longitudinal direction (z), into at least one distribution zone (20) and a heat exchange zone (21), characterized in that a distribution element (22 ) according to one of the preceding claims is arranged in at least one distribution zone (20) of a passage (3).