JP2018511773A - Heat exchanger comprising a microstructural element and separation device comprising such a heat exchanger - Google Patents

Abstract

The present invention relates to a heat exchanger comprising parallel plates and spacers arranged in parallel and defining i) coarse primary channels (21) and ii) secondary channels arranged to exchange heat. The heat exchanger includes a primary liquid inlet that is fluidly connected to a primary liquid dispenser. Each rough primary channel (21) has a polygonal cross section and a prismatic shape consisting of a plurality of substantially flat surfaces. The primary channel includes a coarse primary channel. Each coarse primary channel (21) has a microstructure element (30) distributed along the length of the entire channel and having a dimension between 1 μm and 300 μm. [Selection] Figure 3

Description

  The present invention relates to the exchange of heat between a primary liquid containing, for example, oxygen and a secondary fluid containing, for example, nitrogen. Furthermore, the present invention relates to a cryogenic gas separation apparatus including such heat exchange.

  The present invention relates to the field of heat exchangers configured to perform heat exchange between a primary liquid and a secondary fluid. In particular, the present invention can be applied to the field of cryogenic gas separation, particularly air gas, acid gas, and natural gas separation.

  EP 0130122 A1 generally includes i) primary channels and ii) parallel plates defining parallel channels, parallel spacers, and an inlet connected to the primary liquid bath via a distributor. Including a heat exchanger is described. In general, each primary channel has a generally prismatic shape with a rectangular bottom surface, and the primary liquid circulates along the prism at an angle perpendicular to the rectangular bottom surface.

  When the heat exchanger of EP-A-0130122A1 is in operation, the primary liquid circulating in the primary channel exchanges heat with the secondary fluid flowing in the secondary channel. In the case of a cryogenic air separator, the primary liquid contains the majority of oxygen and the secondary fluid contains the majority of gaseous nitrogen. The flow rate of the primary liquid is relatively low in the primary channel.

  However, as shown in FIG. 1 in this application, the primary channel of EP-A-0130122A1 has a small lateral dimension, in this case millimeter-scale, so that the primary liquids There is no uniform distribution over the entire rectangular perimeter 51 of the primary channel 50. Thus, the primary liquid forms a meniscus 52 and concentrates on the corner 53 of the rectangular perimeter 51 of each smooth primary channel 50, thereby on the long side 54 of the rectangular perimeter 51 of each smooth primary channel 50. The generation of a drying zone is induced.

  As the primary liquid flowing toward the outlet of the smooth primary channel evaporates, the number and surface area of the drying zones increase. Therefore, these drying zones are not used for heat exchange, thus reducing the efficiency of the heat exchanger. In addition, these drying zones can be at risk of depositing impurities, which can ultimately lead to a reduction in worker and equipment safety.

  The object of the present invention is in particular a heat exchanger capable of maintaining the primary and secondary channels having a conventional shape and increasing the heat transfer and safety of the heat exchanger without incurring further head losses. To solve the above-mentioned problems in whole or in part.

Thus, the subject of the present invention is a heat exchanger for causing heat exchange between the primary liquid and the secondary fluid, which heat exchanger is at least:
Several plates arranged parallel to each other;
spacers extending between the plates and arranged parallel to each other to define a primary channel adapted to the flow of the primary liquid and ii) a secondary channel adapted to the flow of the secondary fluid, respectively A spacer arranged such that the primary channel is capable of heat exchange with at least one respective secondary channel;
A primary liquid inlet intended to be fluidly coupled to the primary liquid distributor;
The heat exchanger has a generally prismatic shape with each primary channel having a polygonal cross section, the prisms being composed of several generally flat surfaces;
The primary channel comprises a coarse primary channel, each coarse primary channel having a microstructure element having a dimension between 1 μm and 300 μm, preferably between 1 μm and 100 μm;
The microstructure elements are for each coarse primary channel:
r> 1 + 1.3 · 10 ³ · R _a · ε
(Where:
r is the ratio of the actual surface of each coarse primary channel as the numerator to the geometric surface of each coarse primary channel as the denominator;
R _a (unit m) is the arithmetic mean deviation with respect to the midline, and ε is the actual surface porosity of each coarse primary channel)
It is comprised so that it may become.

The ratio r may also be called “roughness factor” or “roughness”. The arithmetic average deviation R _a (unit m) represents the roughness of the coarse primary channel. In this application, the term “midline” means a line located at the average height of the actual surface. In practice, the midline can be calculated from the topographic record of the cross-sectional profile of the surface by using the least squares method.

  In the present application, the term “surface porosity” corresponds to a ratio calculated as follows: a slice whose thickness is equal to the height of the highest peak of this surface (relative to the lowest point) is considered. To do. On this flake, the porosity ε corresponds to the ratio of the volume not occupied by the microstructure elements to the total volume of the flake. This ratio is expressed as:

In the formula:
V _tot (unit m ³ ) is a volume included between the highest point and the lowest point of the actual surface,
V _surf (unit m ³ ) is a volume included between the actual surface and the lowest point of the actual surface.

  Therefore:

And in the formula:
R _z is the height of the highest peak relative to the lowest point of the surface,
z (unit m) is the height of each point relative to the lowest point of the actual surface, and the height z is measured point by point,

  Is the arithmetic mean of the height z measured point by point.

  For example, such a heat exchanger maintains primary and secondary channels with conventional shapes, thus simplifying manufacture and implementation, and without incurring additional head loss during use of the heat exchanger, It is possible to increase the heat transfer and safety of the heat exchanger. In practice, the microstructural elements allow for increased heat transfer because there is more exchange surface area and wet surfaces. In addition, the high wettability of the primary channel makes it possible to avoid dry evaporation of oxygen, thereby improving the safety of the heat exchanger. Furthermore, measurements have shown that a prismatic shape having a polygonal bottom surface exhibits a greater heat transfer coefficient than, for example, a tubular shape having a circular bottom surface.

  Surface treatment with microstructural elements can wet the entire periphery of the primary channel and thus increase the exchange surface.

  For most applications, the primary liquid and secondary fluid are cryogenic fluids. The primary liquid and secondary fluid introduced into the heat exchanger may be one phase, i.e. all liquid or all gas, or may be composed of two phases, i.e. liquid and gas. While they flow through the heat exchanger, the primary liquid and secondary fluid phase ratios may fluctuate.

  According to one embodiment of the present invention, each polygonal cross section has a dimension between 1 mm and 10 mm, preferably between 3 mm and 7 mm, for example an approximate length of 5 mm and an approximate width of It has a rectangular polygonal cross section that is 1.5 mm.

  For example, such lateral dimensions allow the heat exchanger to be adapted to the primary liquid and secondary fluid flow rates being processed.

  According to one embodiment of the invention, the microstructure elements are distributed substantially throughout the interior perimeter of each coarse primary channel.

  For example, such a distribution ensures wetting of all polygonal cross sections of each coarse primary channel.

  According to one embodiment of the invention, for each rough primary channel, the microstructure elements are distributed over at least 80% of the surface of the rough primary channel.

  For example, each coarse primary channel is substantially covered with a microstructure element that increases the exchange surface area.

According to one embodiment of the invention, the microstructure elements have dimensions similar to each other and forms similar to each other, in which the microstructure elements relate to each coarse primary channel:
r> 1 + 1.3 · 10 ³ · h · ε
(Where h (unit m) is the average height of the microstructure elements)
It is comprised so that.

  For example, such a similar microstructure element allows each coarse primary channel to obtain higher wettability and control the minimum thickness of the primary liquid film.

  For example, similar dimensions of the microstructure elements can show a 20% deviation between the microstructure elements. Two microstructure elements with similar morphology are similar in all their dimensions.

  In the present application, the term “actual surface” means in particular the surface obtained after production, and the term “geometric surface” particularly means a complete surface, and thus a smooth surface excluding existing microstructural elements. And the geometric surface can be completely defined geometrically by nominal dimensions. A geometric surface is sometimes referred to as a “projection surface” when considered to be in one plane.

  In this application, the term “surface” can mean either a topological element or a surface area of this topological element.

  According to one embodiment of the invention, the microstructure elements are evenly distributed. In particular, the microstructural elements are similar and can be distributed uniformly.

  For example, such a uniform distribution can ensure higher wettability of each coarse primary channel and can control the minimum thickness of the primary liquid film.

  Apart from the above embodiments, the microstructure elements are similar and may be unevenly distributed, for example irregularly.

  According to one embodiment of the invention, the microstructure elements are for each coarse primary channel:

(Where:
d (unit m) is the average distance between the centers of adjacent microstructure elements, which are located on the geometric surface of the coarse primary channel,
P (unit m) is the average perimeter of the cross section of the microstructure element)
It is comprised so that.

  According to one embodiment of the invention, the microstructure elements are for each coarse primary channel:

  And the microstructure element (30) is for each coarse primary channel (21):

(Wherein S (unit m ² ) is the average surface area of the cross section of the microstructure)
It is also configured to be.

  A microstructure element configured in this way makes it possible to have a liquid propagation velocity adapted to the heat exchange method.

  According to an embodiment of the invention, the microstructure elements have an irregular shape, for example with irregular dimensions, and the microstructure elements can also be distributed unevenly, for example irregularly.

  In other words, across the actual surface of the rough primary channel considered, the spacing between two adjacent microstructure elements can vary and is therefore not constant.

  For example, with such a non-uniform distribution, by limiting the surface area of each zone that does not have a microstructure element, it is possible to roughen each coarse primary channel and obtain a constant wetting property throughout.

Apart from this variant, each microstructure element can have a regular form or shape, for example it can have a generally cylindrical, prismatic, conical or similar form. In this variant, a regular form of microstructure element is associated with each coarse primary channel:
r> 1 + 1.3 · 10 ³ · h · ε
It is comprised so that.

However, in one variation where the microstructure element has an irregular shape, the microstructure element is:
r> 1 + 1.3 · 10 ³ · R _a ε
It is comprised so that.

  According to one embodiment of the invention, the microstructure elements are for each coarse primary channel:

  It is comprised so that.

  Such microstructural elements in particular create a roughness that increases the wettability of the surface of each rough primary channel, so that the liquid wets the entire surface of the rough primary channel even in the presence of indentations. be able to.

  According to one embodiment of the present invention, each coarse primary channel has a generally prismatic shape with a rectangular bottom, except for at least a portion of the coarse primary channel.

  When the adjective “overall” is indicated, the prism may have a generally rectangular base. For example, the rectangular sides that define the bottom surface of the prism may be rounded, for example by brazing.

  For example, such a form of a coarse primary channel having a rectangular bottom surface can maintain a coarse primary channel and a secondary channel having a conventional shape, thus making it possible to manufacture and implement a heat exchanger assembly. It can be easy.

  According to one embodiment of the invention, the microstructure elements are distributed only on the long sides of the rectangular bottom.

  In other words, the short side around the rectangle does not have any microstructure elements. In practice, the short sides can be wetted because the meniscus is naturally formed at the corners around the rectangle.

  According to one embodiment of the invention, the microstructure elements are distributed such that a flow path through which the primary liquid flows is defined therebetween.

  In other words, the microstructure element extends entirely above the height of the geometric surface.

  For example, the microstructure elements are distributed such that a surface condition is defined having an open roughness, i.e. a roughness defined by peaks or locks but without narrow voids. A void is considered narrow when the surrounding mountains are too close to each other to allow liquid to circulate.

According to one embodiment of the present invention, each of the coarse primary channel has an arithmetic roughness R _a of between 1Myuemu～60myuemu.

  For example, such arithmetic roughness enables a coarse primary channel to obtain high wettability.

  According to one embodiment of the invention, each coarse primary channel has nanostructure elements distributed over at least 80% of its length, each nanostructure element having a dimension between 1 nm and 500 nm.

  For example, such nanostructured elements can maximize the wettability of each coarse primary channel.

  According to a variant of the invention, the nanostructure elements are distributed over the surface of each rough primary channel. Apart from or in addition to this variant of the invention, the nanostructure elements can be distributed over the surface of the microstructure elements.

  According to a variant of the invention, the coating is composed of a metallic material and / or an inorganic material, for example a ceramic material. The coating can be obtained by spray deposition of particles and / or fibers (sometimes referred to as “spray”) onto the surface of each rough primary channel.

  According to one embodiment of the invention, the microstructural elements are produced by treatment of the surface of the respective primary element, for example by anodic oxidation, sand blasting, shot blasting or chemical etching, or even powder sintering, molten metal spray, laser , Photolithography, or rolling, brushing, or printing mechanical etching.

  Furthermore, the microstructure elements can be formed by impregnation, spray deposition, plasma deposition, additive manufacturing methods such as coatings obtained by three-dimensional printing.

  According to a variant of the invention, the plates and / or spacers are made of aluminum, copper, nickel, chromium, iron and aluminum alloys, copper alloys, nickel alloys, chromium alloys, iron alloys, such as nickel- It is made of a material selected from the group consisting of a chromium alloy or a nickel-chromium-iron alloy.

  For example, such plates and / or spacers contain oxygen-containing liquid oxygen and nitrogen containing to separate standard primary liquids and secondary fluids in the field of cryogenic technology, such as air gas, acid gas, and natural gas Gas handling becomes possible.

  According to one embodiment of the invention, the heat exchanger is configured to form an evaporator-condenser, wherein the length of the coarse primary channel and the length of the secondary channel are obtained by exchanging the primary liquid by heat exchange. It is determined that it is possible to fully or partially vaporize and fully or partially condense a secondary fluid introduced in the form of a secondary gas.

  For example, such an evaporator-condenser allows the handling of standard primary liquids and secondary fluids in the field of cryogenic technology, such as oxygen-containing liquids and nitrogen-containing gases to separate air components. .

  According to one embodiment of the invention, during operation of the heat exchanger, the primary liquid inlet is located higher than the coarse primary channel, whereby the primary liquid in the form of a membrane introduced by the primary liquid distributor is , By gravity from the at least one primary liquid inlet into the coarse primary channel.

  According to a variant of the invention, the secondary channels comprise coarse secondary channels, each coarse secondary channel being formed in a manner similar to the coarse primary channel. In particular, the coarse secondary channel can have a microstructure element having a dimension between 1 μm and 300 μm, preferably between 1 μm and 100 μm, and satisfying the formula applicable to the coarse primary channel. More generally, each of the features described above for the coarse primary channel can be applied to the coarse secondary channel. However, these features are not repeated here to facilitate interpretation of this patent application.

  Furthermore, the subject of the present invention is a separation device for separating gases by cryogenic techniques, which separation device comprises a heat exchanger according to the invention forming at least one evaporator-condenser, The vessel-condenser is configured to exchange heat between the oxygen-containing liquid and the nitrogen-containing gas.

  For example, such cryogenic gas separation devices allow the handling of standard primary liquids and secondary fluids in the field of cryogenic technology, such as oxygen-containing liquids and nitrogen-containing gases to separate air components. .

  The foregoing embodiments and variations can be handled independently or in any technically acceptable combination.

  The present invention will be fully understood and its advantages will become apparent when considering the following description, provided solely by way of non-limiting example with reference to the accompanying drawings.

2 is a cross section of a prior art smooth primary channel. 1 is a schematic perspective view of a separation device according to the present invention including a heat exchanger according to the present invention. 2 is a cross-section of a coarse primary channel according to a first embodiment of the present invention. FIG. 2 is a perspective view showing a microstructure element disposed on the coarse primary channel of FIG. 1. FIG. 6 is a perspective view showing a microstructure element disposed on a coarse primary channel according to a second embodiment of the present invention. FIG. 5 is a schematic cross-sectional view of a pattern forming the coarse primary channel microstructure element of FIG. 4. FIG. 6 is a schematic cross-sectional view of a pattern forming a coarse primary channel microstructure element according to a third embodiment of the present invention.

  2, 3 and 4 show a heat exchanger 1 for causing heat exchange between the primary liquid and the secondary fluid. The heat exchanger 1 belongs to a separation device 2 for separating air components by cryogenic technology.

  In the example of FIGS. 2-4, the heat exchanger 1 is configured to form an evaporator-condenser that is configured to exchange heat between an oxygen-containing liquid and a nitrogen-containing gas. Thus, the plate heat exchanger 1 can be used to vaporize an oxygen-rich liquid by exchanging heat with a nitrogen-rich gas concomitantly condensed.

  The heat exchanger 1 includes several plates 11 arranged parallel to each other, and spacers 12 extending between the plates 11 and also arranged parallel to each other. 2 to 4, the plate 11 and the spacer 12 are made of an aluminum alloy. The plates 11 are brazed together in a known manner.

Spacer 12 is:
i) a primary channel which in this case is adapted to the flow of a primary liquid containing liquid dioxygen (O2L) and which includes a coarse primary channel 21;
ii) a secondary channel 22 adapted to the flow of a secondary fluid containing in this case gaseous dinitrogen (N2G);
Are arranged to define

  Each coarse primary channel 21 is arranged so that heat can be exchanged with the two respective secondary channels 22. Therefore, the coarse primary channel 21 and the secondary channel 22 are alternately arranged in the stacking direction D of the plate 11. Here, the coarse primary channel 21 and the secondary channel 22 are mounted in a countercurrent configuration. Alternatively, the coarse primary channel 21 and secondary channel 22 can be mounted in a co-current configuration.

  The heat exchanger 1 also includes a primary liquid inlet 14 that is fluidly connected to the primary liquid distributor 6 belonging to the separation device 2. The primary liquid O2L forms a bath on the primary liquid distributor 6.

  During operation of the heat exchanger 1, the inlet 14 is positioned higher than the coarse primary channel 21. The height is measured in the usual way with reference to the upward vertical direction. Thus, the primary liquid is introduced in the form of a membrane by the primary liquid distributor 6 and flows by gravity from the inlet 14 into the coarse primary channel.

  Furthermore, each coarse primary channel 21 is generally prismatic in shape with a polygonal cross section and extends along the longitudinal direction X. This prism is composed of several generally flat surfaces. The rectangular sides that define the bottom of the prism are now slightly rounded by brazing. Each polygonal cross section or polygon perimeter of the prism has a dimension between 1 mm and 5 mm here.

  As shown in FIG. 3, each coarse primary channel 21 in this case has a generally prismatic shape with a rectangular bottom and extends along the longitudinal direction X. In this case, the rectangular cross section has an approximate height H21 equal to 4.5 mm and an approximate width W21 equal to 1.5 mm. During operation of the heat exchanger 1, the primary liquid flows along the prisms at right angles to the rectangular bottom.

  Further, as shown in FIG. 3, each coarse primary channel 21 has a microstructure element 30. The microstructure elements 30 are distributed or arranged over at least 80% of the length L21 of the coarse primary channel 21 considered. In order to indicate the dimensions of the separation device 2, the length L21 of the coarse primary channel 21 and the length of the secondary channel 22 are introduced in the form of a secondary gas, evaporating all or part of the primary liquid by heat exchange. It is determined that it is possible to condense all or part of the secondary fluid.

Each microstructure element 30 has a dimension between 1 μm and 300 μm. Each microstructure element 30 here has the form of a generally narrow cylinder. As shown in FIG. 4, the microstructure elements 30 have similar dimensions and configurations to each other. The microstructure element 30 is associated with each coarse primary channel 21:
r> 1 + 1.3 · 10 ³ · R _a · ε
(Where:
r is the ratio of the actual surface of each coarse primary channel 21 as a numerator to the geometric surface of each coarse primary channel 21 as a denominator;
R _a (unit m) is the arithmetic mean deviation relative to the midline, and ε is the actual surface porosity of each coarse primary channel 21)
It is comprised so that.

In the example of FIGS. 1-4, the microstructure elements 30 are regularly and uniformly distributed, which are for each coarse primary channel 21:
r> 1 + 1.3 · 10 ³ · h · ε
(Where h (unit m) is the average height of the microstructure elements 30 and this average height is calculated from the height H30 of each microstructure element 30)
It is comprised so that.

  In the example of FIG. 4, the microstructure elements 30 are not distributed over the entire rectangular cross section of each coarse primary channel 21. On the contrary, the microstructure elements 30 are distributed only on the long side 44 of the rectangular cross section of each coarse primary channel 21 and not on the short side 45. In other words, the short side 45 has no microstructure element 30 at all. Actually, the short side 45 is wetted because the meniscus is naturally formed at the corners of the rectangular cross section.

  The microstructure elements 30 are distributed so as to define a flow path through which the primary liquid O2L flows therebetween, thereby defining a surface state having an open roughness. Furthermore, the microstructure elements 30 are uniformly distributed. In other words, the spacing between two successive microstructure elements 30 is substantially constant in all directions. The microstructure elements 30 are thus arranged in a uniform and regular matrix.

The microstructure element 30 is in this case for each coarse primary channel 21:
r> 1 + 1.3 · 10 ³ · h · ε
It is configured to be in it.

  The microstructure element 30 is in this case for each coarse primary channel 21:

(Where:
d (unit m) is the average distance between the centers of adjacent microstructure elements 30, which are located on the geometric surface of the rough primary channel 21, the average distance being the adjacent microstructure Calculated from the respective distances d30 separating the centers of the elements 30 by two,
P (unit m) is the average perimeter of the cross section of the microstructure element 30)
And, in addition, the microstructure element 30 is in this case for each coarse primary channel 21:

  It is comprised so that.

  Furthermore, the microstructure element 30 is associated with each coarse primary channel 21:

(Wherein S (unit m ² ) is the average surface area of the cross section of the microstructure)
It is comprised so that.

  Due to the presence of the microstructure elements 30, each coarse primary channel 21 has an arithmetic roughness Ra between 1 μm and 60 μm. The arithmetic roughness Ra is one of the statistical parameters representing the arithmetic mean deviation with respect to the midline of the surface of the rough primary channel 21 considered.

  Furthermore, each coarse primary channel 21 can have nanostructure elements (not shown) distributed over at least 80% of its length L21. Each nanostructure element has a dimension between 1 nm and 100 nm. The nanostructure elements can be distributed over the surface of each rough primary channel 21 and the surface of the microstructure element 30.

  Furthermore, the microstructure elements 30 in this case form a coating obtained by spray deposition of particles (sometimes described by the term “spray”) on the surface of the respective rough primary channel 21. The particles forming this coating are in this case composed of a metallic material.

  5 and 6 show a part of the coarse primary channel 121 belonging to a heat exchanger according to a second embodiment of the invention. Since the coarse primary channel 121 is similar to the coarse primary channel 21, the description of the heat exchanger and coarse primary channel 21 described above with reference to FIGS. 121 and its heat exchanger.

  The coarse primary channel 121 differs from the coarse primary channel 21 in that the microstructure element 130 is substantially wider and tall and is wider than the spacing between the two microstructure elements 30.

  FIG. 7 shows a cross section at a part xz of a rough primary channel 221 belonging to a heat exchanger according to a third embodiment of the invention. Since the coarse primary channel 221 is similar to the coarse primary channel 21, the description of the heat exchanger and coarse primary channel 21 described above with reference to FIGS. 221 and its heat exchanger.

  In particular, the coarse primary channel 221 differs from the coarse primary channel 21 in that the microstructure elements 230 are irregular and thus have different shapes and dimensions. Furthermore, the coarse primary channel 221 differs from the coarse primary channel 21 in that, in particular, the microstructure elements 230 are unevenly distributed, in this case irregularly distributed. In other words, the spacing between two adjacent microstructure elements 230 varies across the actual surface of the rough primary channel 221 and is therefore not constant.

The microstructure element 230 is for each coarse primary channel 21:
r> 1 + 1.3 · 10 ³ · R _a · ε
It is comprised so that.

  Middle line in FIG.

Represents the arithmetic mean of the height z measured for each point, e.g. height z1, z2, z3, z4, and z5. R _z is the height of the highest peak relative to the lowest point of the surface.

  Obviously, the present invention is not limited to the specific embodiments described in this patent application, or embodiments within the purview of those skilled in the art. Alternative embodiments can be envisaged from any element equivalent to that shown in this patent application without departing from the scope of the invention.

Claims (19)

A heat exchanger (1) for causing heat exchange between a primary liquid (O2L) and a secondary fluid (N2G) comprising:
Several plates (11) arranged parallel to each other;
i) defining a primary channel (21, 121, 221, 321) adapted to the flow of the primary liquid (O2L); and ii) defining a secondary channel (22) adapted to the flow of the secondary fluid (N2G). Spacers (12) extending between the plates (11) and arranged parallel to each other, each primary channel (21) being in contact with at least one respective secondary channel (22) A spacer (12) arranged to allow heat exchange;
A primary liquid inlet (14) intended to be fluidly coupled to a primary liquid distributor (O2L);
Each primary channel (21) has a generally prismatic shape with a polygonal cross section, said prisms being composed of several generally flat surfaces;
Said primary channels comprise coarse primary channels, each coarse primary channel (21) comprising a microstructure element (30, 130, 230, 330) having a dimension between 1 μm and 300 μm, preferably between 1 μm and 100 μm. Having
Said microstructure element (30) for each coarse primary channel (21):
r> 1 + 1.3 · 10 ³ · R _a · ε
(Where:
r is the ratio of the actual surface of each coarse primary channel (21) as a numerator to the geometric surface of each coarse primary channel (21) as a denominator;
R _a (unit m) is the arithmetic mean deviation with respect to the middle line,
ε is the actual surface porosity of each rough primary channel (21))
It is comprised so that it may become. The heat exchanger (1) characterized by the above-mentioned.   Each polygonal cross section has dimensions (H21, W21) between 1 mm and 10 mm, preferably between 3 mm and 7 mm, for example a rectangle with an approximate length of 5 mm and an approximate width of 1.5 mm The heat exchanger (1) according to claim 1, having a polygonal cross section.   3. A heat exchanger according to claim 1 or 2, wherein the microstructure elements are distributed over substantially the entire inner perimeter of each coarse primary channel.   4. The heat according to claim 1, wherein, for each rough primary channel (21), the microstructure elements (30) are distributed over at least 80% of the surface of the rough primary channel (21). Exchanger. Said microstructure elements (30) have similar dimensions and shapes to each other, said microstructure elements (30) for each coarse primary channel (21):
r> 1 + 1.3 · 10 ³ · h · ε
(Where h (unit m) is the average height of the microstructure element (30))
The heat exchanger (1) according to any one of claims 1 to 4, configured to be   The heat exchanger (1) according to any one of claims 1 to 5, wherein the microstructure elements (30) are uniformly distributed. Said microstructure element (30) for each coarse primary channel (21):

(Where:
d (unit m) is the average distance between the centers of adjacent microstructure elements (30), which centers are located on the geometric surface of the rough primary channel (21);
P (unit m) is the average perimeter of the cross section of the microstructure element (30))
The heat exchanger of claim 6, wherein the heat exchanger is configured to be Said microstructure element (30) for each coarse primary channel (21):

The microstructure element (30) is configured for each coarse primary channel (21):

(Wherein, S (unit m ² ) is an average surface area of the cross section of the fine structure)
The heat exchanger of claim 7, wherein the heat exchanger is also configured to be.   Heat exchange according to any one of the preceding claims, wherein the microstructure elements have an irregular shape and the microstructure elements (30) can also be distributed unevenly, for example irregularly. vessel. Said microstructure element (30) with respect to said respective coarse primary channel (21):

The heat exchanger of claim 9, wherein the heat exchanger is configured to be   11. Each coarse primary channel (21) has a generally prismatic shape with a rectangular bottom, excluding at least a portion of the coarse primary channel (21). The heat exchanger as described (1).   The heat exchanger (1) according to claim 6, wherein the microstructure elements (30) are distributed only on the long sides (44) of the rectangular bottom.   The heat exchanger (1) according to any one of the preceding claims, wherein the microstructure elements (30) are distributed so as to define a flow path between which the primary liquid flows.   14. The heat exchanger (1) according to claim 1, wherein each coarse primary channel (21) has an arithmetic roughness Ra between 1 μm and 60 μm.   15. Each coarse primary channel (21) has nanostructure elements distributed over at least 80% of its length, each nanostructure element having a dimension between 1 nm and 500 nm. A heat exchanger (1) according to claim 1.   Said microstructure element (30) can be processed by treatment of the surface of the respective primary element, for example anodizing, sand blasting, shot blasting or chemical etching, or even powder sintering, molten metal injection, laser, photolithography or roll 16. A heat exchanger (1) according to any one of the preceding claims, formed by brushing, brushing or printing type mechanical etching.   The heat exchanger (1) is configured to constitute an evaporator-condenser, wherein the length of the coarse primary channel (21) (L21) and the length of the secondary channel (22) are By exchanging, the primary liquid (O2L) can be completely or partially vaporized and the secondary fluid (N2G) introduced in the form of a secondary gas can be fully or partially condensed. The heat exchanger (1) according to any one of claims 1 to 16, which is determined.   During operation of the heat exchanger (1), the primary liquid inlet (14) is positioned higher than the coarse primary channel (21), thereby allowing the primary liquid (O2L) to move the primary liquid (O2L). The heat exchange according to any one of the preceding claims, wherein O2L) is introduced in the form of a membrane and flows by gravity from the at least one primary liquid inlet (14) into the coarse primary channel (21). Vessel (1). Separation device (2) for separating gases by cryogenic techniques, comprising a heat exchanger according to claim 13, forming at least one evaporator-condenser, the evaporator-condenser comprising Separation device (2) configured to be able to exchange heat between an oxygen-containing liquid and a nitrogen-containing gas.

Images