Brazed plate heat exchanger with locally deformable sealed section

Abstract

A heat exchanger (1) comprising: - a body (3) with a plurality of compartments (10) through which a fluid can flow, at least one sealed compartment (11), - a separating wall (5) arranged between the compartments (10, 11) and intended to separate the compartments (10, 11) from one another in an air-tight manner, - at least one distribution or collection head (9) for distributing a fluid to the compartments (10) or for collecting a fluid leaving said compartments (10), in which the distribution or collection head (9) is fixed to the body (3) by a welding operation, and in which the at least one sealed compartment (11) can be deformed following the welding operation.

Description

[Technical field]

[0001] The present invention is in the technical field of heat exchangers, and more specifically, the present invention relates to plate heat exchangers filled with powders designed to initiate physical / chemical reactions. [Background technology]

[0002] Brazed plate heat exchangers are traditionally used in the cryogenic industry for gas separation and liquefaction, and in the energy and petrochemical sectors.

[0003] As part of the energy transition with major CO2 emission reduction targets, many countries are showing increased interest in new energy sources. In this context, brazed plate heat exchangers are being adapted for new industrial-scale processes. This is the case for the hydrogen liquefaction process linked to the development of hydrogen mobility.

[0004] For example, hydrogen is more stable at low temperatures in the para-hydrogen state than in the ortho-hydrogen state. At low temperatures, especially liquefaction temperatures, ortho-hydrogen tends to spontaneously convert to para-hydrogen, releasing undesirable heat.

[0005] To keep hydrogen in its liquid state, there are two options: the first is to continuously extract the heat released by the conversion of ortho-hydrogen to para-hydrogen, but in practice this technique has proven to be particularly energy intensive and uneconomical on an industrial scale.

[0006] The second option is to remove the orthohydrogen by converting it to parahydrogen. An exothermic catalytic reaction combined with cooling converts most of the orthohydrogen to parahydrogen. The spontaneous conversion of orthohydrogen to parahydrogen is then reduced.

[0007] This second option is one area in which the present invention can be applied.

[0008] To use catalysts, often in powder form, which are inserted into the heat exchanger after the brazing operation, it is necessary to use hydrogen distribution heads with large openings whose cross section is substantially equal to that of the heat exchanger in question, which ensures a uniform powder distribution in the exchanger section.

[0009] This means that the distribution heads are particularly large and have an impact on the heat exchanger.

[0010] Conventional heat exchangers typically include longitudinal and end bars that define compartments separated from one another by gas-tight separating walls.

[0011] In the case of a distribution head whose cross section is approximately equal to that of the heat exchanger, there are no end bars in the catalyst receiving compartment, since they would prevent the insertion of the catalyst in powder form, but the overall structure of the heat exchanger is weakened, since the end bars contribute to the mechanical strength of the heat exchanger and to the distribution of welding stresses.

[0012] During assembly, the distribution head is welded to the heat exchanger. Weld cooling, material expansion, and material contraction cause mechanical stresses that can distort the main structure of the heat exchanger, reducing its efficiency. A further drawback is that these deformations make it more difficult to fill the heat exchanger with powdered catalyst, resulting in an uneven distribution of catalyst that is detrimental to the performance of the unit.

[0013] The present invention aims to address these shortcomings. Summary of the Invention

[0014] For this purpose, a heat exchanger is provided, a body having a plurality of compartments through which a fluid can flow and at least one sealed compartment; - a separation wall arranged between the compartments and intended to separate the compartments from each other in an air-tight manner; at least one dispensing or collecting head for dispensing fluid into the compartment or collecting fluid exiting the compartment; A heat exchanger, in which the distribution head or the collection head is fixed to the body by a welding operation, and the at least one sealing section is deformable following the welding operation.

[0015] Such a heat exchanger allows the exchanger structure to absorb the mechanical stresses inherent in the cooling of the weld, which makes it easier to fill the powder.

[0016] Various additional features may be provided, either alone or in combination, as set forth below.

[0017] the heat exchanger includes an end closure bar disposed within the end section, the end closure bar being capable of blocking ingress of fluid into the end section, the weld being formed within an orifice laterally defined on one side by the dispensing head and on the other side by the end closure bar; The heat exchanger includes an at least partially deformable section adjacent an end section; The deformable section comprises a deformable area capable of being deformed; the deformable region extends from the inlet of the body for a minimum distance of 3 centimeters, measured in the longitudinal direction of the body; the body includes a reinforcing section adjacent to the deformable section through which fluid may circulate; a deformable waveplate defining a fluid flow path is disposed within the deformable region of the deformable section, a reinforced waveplate defining a fluid flow path is disposed within the reinforced section, the waveplate of the deformable section having a critical buckling load lower than the critical buckling load of the reinforced waveplate; the reinforced wave plate is disposed within a reinforced region of the reinforced section, the reinforced region extending from an inlet of the body over a minimum distance of 3 centimeters, measured in the longitudinal direction of the body; the cross section of the dispensing or collecting head is substantially equal to the cross section of the body; The body includes a powder intended to initiate a physical / chemical reaction; The powder is placed in a compartment through which a fluid can circulate. [Brief description of the drawings]

[0018] Further features and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings. [Figure 1] 1 is a schematic perspective view of a portion of a heat exchanger according to the present invention; [Diagram 2] 1 is a schematic diagram of a cross section of a heat exchanger according to the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] [FIG. 1] shows a heat exchanger 1 according to the present invention. First, a longitudinal axis X is defined, which extends along the length of the heat exchanger 1, corresponding to the maximum dimension of the heat exchanger 1. Second, a first transverse axis Y is defined, which is substantially perpendicular to the longitudinal axis X and extends along the width of the heat exchanger 1. The X and Y axes form a plane XY. Finally, a third transverse axis Z is defined, which is substantially perpendicular to the X and Y axes and extends along the height of the heat exchanger 1. The Z axis forms a plane ZX together with the X axis, and a plane ZY together with the Y axis.

[0020] The heat exchanger 1 comprises several longitudinal bars 2 which together define a body 3 provided with compartments 4 in which a fluid can circulate. Each compartment 4 is bounded laterally along the Y axis by a longitudinal bar 2. The compartments 4 are adjacent to one another; in other words, the compartments 4 are juxtaposed one above the other.

[0021] The heat exchanger 1 comprises partitions 5. Between each compartment 4 a separation wall 5 is arranged, which therefore separates the compartments 4 from each other along the Z axis.

[0022] On either side of the heat exchanger 1 along the Z axis, the heat exchanger comprises end sections 6 located at lateral ends 7. A closure wall 8 is arranged on each end section 6, thus closing the heat exchanger 1.

[0023] As shown in FIG. 1, the heat exchanger 1 includes a fluid distribution head 9 located at the inlet 17 of the heat exchanger 1. The distribution head 9 has a cross section in the ZY plane substantially equal to the cross section of the body 3 of the heat exchanger 1.

[0024] The fluid thus dispensed by the dispensing head 9 is dispensed into accessible compartments 4 arranged along the Z axis.

[0025] The heat exchanger 1 further comprises a collection head (not shown) arranged opposite the distribution head 9. The collection head collects the fluid exiting the compartment.

[0026] With reference to FIG. 2, the heat exchanger 1 comprises an open compartment 10 through which a fluid can circulate and a compartment 11 closed by bars 12, 13 through which the fluid cannot at least partially circulate.

[0027] The compartment 11 is sealed to at least partially prevent the circulation of fluid therein. Advantageously, the sealed compartment 11 is sealed by transverse closure bars 12, 13 extending along the Y axis.

[0028] The dispensing head 9 is attached to the body 3 by welding. Once the welding is complete, cooling of the metal 15 creates mechanical stresses in the body 3. These mechanical stresses are commonly referred to as "material shrinkage".

[0029] Advantageously, at least one of the sealing sections 11 is at least partially deformable. The deformable section 11 thus absorbs the mechanical stresses caused by the welding operation. The structure of the heat exchanger 1 is not damaged. In the following, for each adjacent section 16, reference is made to the deformable sealing section 11.

[0030] Advantageously, the heat exchanger 1 comprises an end closure bar 13 extending along the Y axis and arranged inside the end section 6. The end closure bar 13 is arranged at the inlet 17 of the end section 6. The end closure bar 13 therefore blocks the inflow of fluid into the end section 6.

[0031] Advantageously, the end closure bar 13 is chamfered in its part facing the dispensing head 9. The end closure bar 13 thus defines, together with the dispensing head 9, an orifice 14. The orifice 14 is defined laterally on one side by the dispensing head 9 and on the other side by the end closure bar 13. The welding is performed in the orifice 14. In other words, the weld metal 15 is deposited in the orifice 14.

[0032] In addition to acting as a support for the weld metal 15, the end closure bars 13 prevent significant deformation of the end sections 6, which would in fact tend to weaken the dispensing head 9 or the collecting head.

[0033] Advantageously, the body 3 comprises an adjacent section 16, which is at least partially deformable. The section 16 is adjacent and surrounded by the end section 6. As can be seen in FIG. 2, the adjacent section 16 is adjacent to the end section 6 along the Z axis. As a result of material shrinkage after the welding operation, the adjacent section 16 is deformed. In other words, the cross section of the adjacent section 16 is reduced as a result of the welding operation. This deformation of the adjacent section 16 makes it possible to absorb mechanical stresses due to material shrinkage, thus preserving the integrity of the heat exchanger 1. In particular, this prevents the welds from deteriorating, which would lead to undesirable leaks.

[0034] Advantageously, adjacent compartments 16 are provided with closure bars 12 designed to block the passage of fluids.

[0035] The body 3 of the heat exchanger 1 comprises a deformable region 18. The deformable region 18 of an adjacent section 16 is that part of said adjacent section 16 which deforms under the effect of stresses caused by the welding operation.

[0036] Such localized deformable regions 18 maintain the integrity of the heat exchanger 1 even after material contraction.

[0037] The deformable region 18 extends from the inlet 17 over a distance d measured along the X-axis. Advantageously, the distance d is at least 3 centimeters.

[0038] Advantageously, the body 3 of the heat exchanger 1 comprises a reinforcing section 19. The reinforcing section 19 is arranged adjacent to the deformable section 16. The reinforcing section 19 is open so that fluid can flow through it. The reinforcing section 19 stops the deformation of the deformable region 18 in order to prevent the cross section of the other open section 10 from decreasing. At the end of the welding operation, the reinforcing section 19 is not significantly deformed.

[0039] Advantageously, the body 3 comprises a wave plate 20. The wave plate 20 defines a circulation channel through which a fluid can flow. The wave plate 20 is arranged in the open section 10 and in the closed section 11.

[0040] In the open section 10, a wave plate 20 guides the fluid through the channels. In the case of a catalytic heat exchanger 1, the channels are filled with a catalytic agent, usually in powder form. The fluid passes through the channels and thus through the powder which acts as a catalyst.

[0041] In the closed sections 11, the wave plates 20 act as "deformable dampers". In this way, they provide these sealed sections 11 with a degree of resistance to stresses to prevent them from deforming too easily during various operations such as brazing or welding.

[0042] Advantageously, the deformable wave plate 30, which defines the fluid circulation channel, is placed in the deformable region 18 of the deformable section 16. The reinforced wave plate 40, which defines the fluid circulation channel, is placed in the reinforced region 22 of the reinforced section 19. The wave plate 30 in the deformable section 16 has a lower critical buckling load than the reinforced wave plate 40. This makes it possible to identify the position of the deformable region 18. It is therefore the deformable region 18 that deforms after the welding operation, while the reinforced region 22 does not deform significantly. In this way, the deformation can be controlled by concentrating it at a desired point that is considered safe for the heat exchanger. The deformation is not random. By deformation, we mean that the deformable region 18 deforms elastically and is held in an elastically deformed position by the weld 15. The deformation is therefore not ductile and irreversible.

[0043] Advantageously, the reinforced area 22 extends over a distance r measured along the X-axis from the inlet 17. The distance r is at least 3 centimeters. The reinforced area 22 having these dimensions strengthens the heat exchanger and prevents deformation of the other open sections 10 located below the reinforced section 19.

Claims

1. A heat exchanger (1), comprising: a body (3) provided with a plurality of compartments (10) through which a fluid can flow, at least one sealed compartment (11), and a separation wall (5) arranged between said compartments (10, 11) and intended to hermetically separate said compartments (10, 11) from one another; at least one dispensing or collecting head (9) for dispensing fluids into said compartment (10) or for collecting fluids exiting said compartment (10), The heat exchanger (1), in which the distribution or collection head (9) is fixed to the body (3) by a welding operation, and the at least one sealing section (11) is deformable following the welding operation.

2. 2. The heat exchanger (1) according to claim 1, further comprising an end closure bar (13) arranged in the end section (6), the end closure bar (13) being capable of blocking the ingress of a fluid into the end section (6), the weld being formed in an orifice (14) defined laterally on one side by the distribution head (9) and on the other side by the end closure bar (13).

3. 3. The heat exchanger (1) according to claim 2, wherein the heat exchanger (1) comprises an at least partially deformable section (16), the section (16) being adjacent to the end section (6).

4. 4. The heat exchanger (1) according to claim 3, wherein the deformable section (16) comprises a deformable region (18) which is deformable.

5. 5. The heat exchanger (1) according to claim 4, wherein the deformable area (18) extends from the inlet (17) of the body (3) over a distance (d) of at least 3 centimeters measured in the longitudinal direction of the body (3).

6. A heat exchanger (1) according to any one of claims 3 to 5, wherein the body (3) comprises, adjacent to the deformable section (16), a reinforcing section (19) through which a fluid can flow.

7. 7. The heat exchanger (1) of claim 6, wherein a deformable wave plate (30) defining a fluid flow path is disposed within the deformable region (18) of the deformable section (16), and a reinforced wave plate (40) defining a fluid flow path is disposed within the reinforced section (19), and the wave plate (30) of the deformable section (16) has a critical buckling load that is lower than the critical buckling load of the reinforced wave plate (40).

8. 8. The heat exchanger (1) according to claim 7, wherein the reinforcing wave plate (40) is arranged within a reinforcing region (22) of the reinforcing section (19), the reinforcing region (22) extending over a minimum distance of 3 centimeters measured in the longitudinal direction of the body (3) over a distance (r) measured from the inlet (17) of the body (3).

9. A heat exchanger (1) according to any one of the preceding claims, wherein the cross section of the distribution or collection head (9) is substantially equal to the cross section of the body (3).

10. The heat exchanger (1) according to any one of the preceding claims, wherein the body (3) contains a powder intended to initiate a physical / chemical reaction.

11. 11. The heat exchanger (1) according to claim 10, wherein the powder is arranged in the compartment (10) through which a fluid can circulate.

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