Heat exchanger module and method

Abstract

Heat exchanger module (2) comprising: - a body (3) comprising at least two spiral sheets (31, 32), the sheets delimiting between them a first circulation channel (50) for a first fluid (A) and a second circulation channel (51) for a second fluid (B); and - a separator (4) for receiving the first fluid (A) capable of allowing a first fraction (A1) of the first fluid (A) to pass to another heat exchanger module located below the heat exchanger module, and of preventing a second fraction (A2) of the first fluid (A) from reaching the other heat exchanger module, the first fraction (A1) of the first fluid containing a gaseous phase, and the second fraction (A2) of the first fluid consisting of a liquid phase.

Description

DOMAINE TECHNIQUE

[0001] This presentation concerns heat exchangers, in particular spiral heat exchangers configured to process a liquid phase of a fluid. ETAT DE LA TECHNIQUE

[0002] A spiral heat exchanger module typically comprises a central tubular section and a spiral body consisting of at least two sheets wound spirally around the central tubular section. The central tubular section may be formed by a wound portion of the two sheets or by a separate tubular piece to which the two sheets are welded.

[0003] The two spiral-wound metal sheets around the central tubular section define a first spiral circulation channel for a hot fluid and a second spiral circulation channel for a cold fluid. The circulation of the hot and cold fluids within these spiral channels allows for heat exchange between the fluids.

[0004] The modules can be configured to be stacked vertically to create a multi-stage heat exchanger. To achieve this, each module has openings at its ends designed to connect to one another. This allows the hot fluid to undergo several successive heat exchanges within the heat exchanger assembly.

[0005] However, in some applications, the hot fluid being treated may consist primarily of a gaseous phase, and each heat exchange results in the condensation of a fraction of this gaseous phase. Thus, the proportion of liquid phase in the hot fluid increases as it passes through successive modules. This increased proportion of liquid phase can reduce the efficiency of heat exchange.

[0006] Indeed, on the one hand, some of the heat transferred between the hot and cold fluids is used to cool the liquid phase, thus limiting the cooling efficiency of the gaseous phase. On the other hand, the liquid phase can contain chemical compounds that tend to form deposits on the internal walls of the heat exchanger modules and can, over time, cause clogging of the first circulation channel.

[0007] FR-A-3096443 discloses a heat exchanger module according to the preamble of claim 1. EXPOSE GENERAL

[0008] One aim of this presentation is therefore to improve the efficiency of heat exchange within a multi-stage heat exchanger system.

[0009] To this end, according to the first aspect of this presentation, a heat exchanger module is proposed comprising: a body comprising at least two sheets, each sheet being wound spirally around the same main axis, the sheets including a first sheet and a second sheet delimiting between them a first circulation channel for a first fluid and a second circulation channel for a second fluid, separate from the first circulation channel, the first sheet and the second sheet having edges defining a first face of the body and a second face of the body, opposite to the first face, the first face and the second face extending transversely to the main axis, the first face having first inlet openings to allow circulation of the first fluid from outside the body to the first circulation channel, and the second face having first outlet openings to allow circulation of the first fluid from the first circulation channel to the outside of the body;and a separator to receive the first fluid flowing through the first outlet openings, the separator being suitable for allowing a first fraction of the first fluid to pass to the first inlet openings of another heat exchanger module located below the heat exchanger module, and for preventing a second fraction of the first fluid from reaching the first inlet openings of the other heat exchanger module, the first fraction of the first fluid containing a gaseous phase, and the second fraction of the first fluid being made up of a liquid phase.

[0010] Thus, the separator prevents a portion of the liquid phase of the first fluid—for example, at least 80% of the liquid phase—from entering the next module in the stack. The proposed solution therefore proportionally reduces the liquid phase and increases the efficiency of heat exchange within the multi-stage heat exchanger.

[0011] In one possible embodiment, the separator may be provided to include a passage allowing circulation of the first fraction of the first fluid towards first inlet openings of the other heat exchanger module, and a first separation wall having a first collection surface arranged to receive the first fluid from the first outlet openings, the first collection surface being oriented with respect to the main axis to guide the first fraction of the first fluid by gravity away from the second fraction of the first fluid of the passage.

[0012] It can also be provided that the first collection surface is oriented with respect to the main axis to guide the second fraction of the first fluid by gravity towards an outlet pipe of the first fluid.

[0013] Therefore, gravity can be advantageously used to prevent the liquid phase of the first fluid from entering the next module. Thus, no additional energy input is required for separation.

[0014] It can be envisaged that the first separating wall has a conical shape, having an axis coinciding with the main axis.

[0015] It may also be provided that the passage includes a passage opening located at a summit of the cone.

[0016] It may be provided that the separator includes a second separating wall arranged to prevent the first fraction of the first fluid from the first outlet openings from reaching the passage.

[0017] It can also be provided that the second separating wall extends around the main axis.

[0018] It can also be provided that the second separating wall has a second collection surface oriented with respect to the main axis to guide the first fraction of the first fluid by gravity towards the first collection surface.

[0019] Thus, heat exchange is further improved by separating more liquids from the first fluid.

[0020] It can be envisaged that the second separating wall has a conical shape, having an axis coinciding with the main axis.

[0021] It may be provided that the heat exchanger module includes an inlet tube to inject the second fluid from outside the body into the second circulation channel and a first outlet tube to evacuate the second fluid from the second circulation channel to the outside of the body.

[0022] Thus, it is possible to remove the liquid phase from the module. This removal also allows the liquid phase to be used, for example, by recirculating it back into the module after heating it.

[0023] It may be provided that the module includes a nozzle to spray a cleaning product into the first fluid at the point where the first fluid enters the first circulation channel via the first inlet openings.

[0024] Thus, the cleaning product helps to reduce the risk of clogging the first circulation channel in which the first fluid circulates and to further improve heat exchange.

[0025] According to a second aspect of this presentation, a heat exchanger assembly is proposed, comprising at least two heat exchanger modules conforming to the first aspect, the heat exchanger modules being connected together, so that the first fraction of the first fluid containing the gaseous phase from one heat exchanger module of the heat exchanger assembly enters the first circulation channel via the first inlet openings of the body of another heat exchanger module of the heat exchanger assembly.

[0026] It may be provided that each heat exchanger module includes nozzles for spraying a cleaning product into the first fluid at the point where the first fluid enters the first circulation channel via the first inlet openings, the heat exchanger assembly including a control unit configured to control a flow rate and / or temperature of the cleaning product sprayed by each nozzle of each heat exchanger module as a function of a difference between a pressure of the first fluid at the outlet of the first outlet openings and a pressure of the first fluid at the inlet of the first inlet openings of the body of the heat exchanger module.

[0027] The cleaning product can therefore be injected as soon as the heat exchange decreases in the module, thus saving cleaning product.

[0028] According to a third aspect of this presentation, a process for treating a first fluid is proposed, comprising the following steps: circulate the first fluid in a first circulation channel of a body of a first heat exchanger module conforming to the first aspect, separate the first fluid flowing through the first outlet openings of the body of the first heat exchanger module into a first fraction of the first fluid containing a gaseous phase, and into a second fraction of the first fluid consisting of a liquid phase, evacuate the second fraction of the first fluid, and inject the first fraction of the first fluid into a first circulation channel of a body of a second heat exchanger module.

[0029] It can be expected that the second heat exchanger module will conform to the first aspect. DESCRIPTION DES FIGURES

[0030] Other features, purposes, and advantages will become apparent from the following description, which is purely illustrative and not exhaustive, and should be read in conjunction with the attached drawings on which: there figure 1 and the figure 2 illustrate heat exchanger assemblies; the figure 3 schematically illustrates a cross-sectional top view of an example heat exchanger module; the figure 4 schematically illustrates a cross-sectional front view of a heat exchanger module; and the figure 5 is a flowchart of a method for implementing a fluid treatment process. DESCRIPTION DETAILLEE

[0031] A heat exchanger assembly 1, also called a multi-stage heat exchanger, is illustrated on the figures 1 And 2The heat exchanger assembly 1 is several meters high, for example 4 meters, and has a floor area of ​​several square meters, for example 5 m². The heat exchanger assembly 1 has a mass of several hundred tons, for example 350 tons.

[0032] In normal operation, the heat exchanger assembly 1 is vertical. The heat exchanger assembly 1 comprises a plurality of heat exchanger modules 2a, 2b, 2c stacked and fixedly connected to one another. In the example illustrated in figures 1 And 2The heat exchanger assembly 1 comprises three heat exchanger modules 2a, 2b, 2c. Of course, the heat exchanger assembly 1 may comprise more or fewer than three modules. In this example, the modules are cylindrical, but they may also be cubic, elliptical, or any other shape suitable for fabrication from sheet metal assembly or casting. A first inlet pipe 5 communicates with an upper end of the heat exchanger assembly 1, and a first outlet pipe 7, opposite the inlet pipe 5, communicates with a lower end of the heat exchanger assembly 1. Each heat exchanger module 2a, 2b, 2c comprises a respective inlet pipe 6a, 6b, 6c and a respective outlet pipe 8a, 8b, 8c. Each heat exchanger module 2a, 2b, 2c may also include multiple inlet pipes and / or multiple outlet pipes.Fittings 9a, 9c between inlet and outlet pipes are configured to mutually connect the heat exchanger modules. The heat exchanger assembly 1 is configured to perform heat exchange between a first fluid A and a second fluid B in each heat exchanger module 2a, 2b, 2c. During operation, a first fluid A, for example a hot fluid to be cooled, enters the heat exchanger assembly 1 through the inlet pipe 5, at the upper level of the heat exchanger assembly, and exits the heat exchanger assembly 1 through the outlet pipe 7, at the lower level of the heat exchanger assembly 1. Thus, the first fluid A flows by gravity through the heat exchanger assembly 1, circulating successively through each heat exchanger module 2a, 2b, 2c.In each heat exchanger module 2a, 2b, 2c, the first fluid exchanges heat with a second fluid B, for example a refrigerant fluid, which circulates through the heat exchanger assembly 1 through the inlet tubes 6a, 6b, 6c and outlet tubes 8a, 8b, 8c of each module 2a, 2b, 2c.

[0033] An example of a heat exchanger module 2 is illustrated on the figures 3 And 4The heat exchanger module 2 comprises a body 3 through which the first fluid A and the second fluid B can circulate to achieve heat exchange between the first fluid A and the second fluid B. The body 3 comprises four plates 31, 32, 33, 34. The plates 31, 32, 33, 34 are wound spirally around the same principal axis X, the plates delimiting between them a first circulation channel 50 and a second circulation channel 51. The heat exchanger module 3 is configured to circulate the first fluid A longitudinally with respect to the principal axis X through the first circulation channel 50. To achieve this, a first face of the body and a second face of the body opposite the first face are defined by an edge 310, 311 of each plate 31, 32, 33, 34.The first face has inlet openings 24 to allow the first fluid A to flow from outside the body 3 to the first circulation channel 50, and the second face has outlet openings 25 to allow the first fluid A to flow from the first circulation channel 50 to the outside of the body 3. Thus, the first fluid A enters the body 3 through the inlet openings 24 and then flows in the first channel 50, delimited by the second and third plates 32, 33 and the fourth and first plates 34, 31, until it reaches the outlet openings 25. The heat exchanger module 2 is further configured to allow the second fluid B to flow between the inlet pipe 6 and the outlet pipe 8. The second circulation channel 51 is spiral-shaped.Thus, the second fluid B enters the body 3 through the inlet pipe 6 and circulates firstly in a spiral towards the interior of the body 3 in the second channel 51 delimited by the first plate 31 and the second plate 32 to converge to the main axis X then, it circulates a second time in a spiral towards the exterior of the body 3 still in the second channel 51 delimited this time by the third plate 33 and the fourth plate 34 in order to move away from the main axis X until reaching the outlet pipe 8. Consequently, during the circulation of the two fluids A, B in the two channels 50, 51, a heat exchange takes place between the first fluid A and the second fluid B, through the plates 31, 32, 33, 44.

[0034] Of course, body 3 can include other sets of sheets, for example three sheets or two sheets, the number of sheets being limited to at least two in order to be able to delimit the first channel 50 and the second channel 51.

[0035] The heat exchanger module 2 further includes a separator 4 configured to separate a liquid phase from a gaseous phase of the first fluid A at the outlet of the heat exchanger module 2. On the one hand, the separator 4 is suitable for allowing a first fraction A1 of the first fluid A, predominantly in gaseous phase, to pass to the inlet openings of another heat exchanger module located below the heat exchanger module in the stack and, on the other hand, for preventing a second fraction A2, consisting of a liquid phase, from reaching the first inlet openings of the other heat exchanger module.

[0036] An example of a separator 4 is illustrated in figure 4 When the heat exchanger module 2 is in normal operation, the separator 4 is located below the outlet openings 25. The separator 4 comprises a first wall 41 and a second wall 42 situated above the first wall 41. The first wall 41 and the second wall 42 are each conical in shape, with their axis along the principal axis X. The walls 41 and 42 may also be inclined planes or any other surface inclined with respect to the principal axis X. When the first fluid A passes through the separator 4, a first portion of the second fraction A2 is collected directly by the first wall 41 (without flowing over the second wall 42), and a second portion of the second fraction A2 is collected by the second wall 42 and then guided by the second wall 42 back to the first wall 41. Thus, the second fraction A2, consisting of a liquid phase, is recovered by the first wall 41, which forms a liquid phase recovery surface.The first wall 41 and the second wall 42 are inclined with respect to the main axis X, so that when the axis X is positioned vertically (in normal use), the first wall 41 and the second wall 42 guide the second fraction A2 of the first fluid A by gravity away from the main axis X.

[0037] The first wall 41 further includes a passage opening 43, through which the first major fraction A1 in the gaseous phase of the first fluid A can flow. In the example illustrated on the figure 4 The passage opening 43 is located at the apex of the cone formed by the first wall 41. The second wall 42 is situated above the first wall 41, but at a distance from it. The first part of the second fraction A2 is guided by the first wall 41 and the second wall 42 to prevent it from flowing through the passage opening 43 towards the heat exchanger module located below. The second wall 42 extends above the passage opening 43, thus preventing the second part of the second fraction A2 from flowing through the passage opening 43 by guiding it towards the first wall 41.The separator 4 thus allows the second fraction A2, consisting of a liquid phase, to be blocked while allowing the first fraction A1, comprising the gaseous phase, to pass through because, when the first and second fractions A1, A2 flow by gravity into the heat exchanger module 2, the second fraction A2, consisting of a liquid phase, is retained by the first recovery wall 41 while the first fraction A1, predominantly in the gaseous phase, is directed to another heat exchanger module 2. To evacuate the second fraction A2 retained by the first wall 41 from the heat exchanger module 2, the heat exchanger module 2 may also include other evacuation pipes 12 communicating with the second surface, as illustrated for example in the diagrams. figures 1 , 2 And 3 , or connected to the second surface.

[0038] On the figure 4 The heat exchanger module 2 includes four nozzles 10 arranged near the point where the first fluid A enters the first circulation channel A via the inlet openings 24. Of course, the heat exchanger module 2 may include a single nozzle, fewer than four nozzles, or more than four nozzles. The nozzles 10 are configured to spray a cleaning agent, in liquid form, into the flow of the first fluid A, in order to clean the metal sheets and prevent components of the first fluid, such as naphthalene, from being deposited on them. The cleaning agent may, for example, be a mixture of water and tar, more commonly known as "tar," which has the effect of loosening the naphthalene from the metal sheets. The naphthalene and the cleaning agent then trickle down to the outlet opening 25.The cleaning product and naphthalene flowing in liquid form from the outlet openings 25 form part of the second fraction A2 which is recovered by the separator 4. Thus, the first fluid A is cleaner at the outlet of each heat exchanger module 2, which has the effect of limiting the risk of clogging in a heat exchanger module 2. Each heat exchanger module 2 of the heat exchanger assembly 1 may include a set of nozzles 10 for spraying cleaning product into the first fluid A at the inlet of the heat exchanger module 2. Alternatively, only one heat exchanger module 2 may include a set of nozzles 10 or several heat exchanger modules 2 may include a set of nozzles 10. The set of nozzles 10 may also be supplied via supply lines 11 (. figure 2 ).

[0039] The heat exchanger assembly 1 may be provided to include a control unit configured to control the flow rate and / or temperature of the cleaning product sprayed by each set of nozzles 10. The control unit may control the flow rate and / or temperature of the cleaning product sprayed by each nozzle of each heat exchanger module 2. The control unit may be provided to control the flow rate and / or temperature of the cleaning product sprayed by a nozzle of each heat exchanger module 2, or of one heat exchanger module 2, or of each module of a plurality of heat exchanger modules. The control unit may also be provided to control the flow rate and / or temperature of the cleaning product sprayed by a plurality of nozzles of each heat exchanger module 2, or of one heat exchanger module 2, or of each module of a plurality of modules.The control unit can further control a flow rate and / or temperature of the cleaning product as a function of a difference between a pressure of the first fluid A at the outlet of the outlet openings 25 and a pressure of the first fluid A at the inlet of the inlet openings 24 of the body 3 of the heat exchanger module 2. The control unit can also control the flow rate and / or temperature of the cleaning product as a function of a minimum, a maximum or an average of a difference between a pressure of the first fluid A at the outlet of the outlet openings 25 and a pressure of the first fluid A at the inlet of the inlet openings 24 of the body 3 in each heat exchanger module 2, or in each module of a plurality of modules.

[0040] Thus, the heat exchanger assembly 1 is capable of implementing a process for treating the first fluid A, in which, with reference to the figure 5 , the following steps are implemented.

[0041] During a step E1, the first fluid A circulates in the first circulation channel 50 of the body of a first heat exchanger module 2a.

[0042] During a step E2, the first fraction A1 of the first fluid A flowing through the first outlet openings 25 of the body 3, predominantly in gaseous phase, is separated from the second fraction A2 of the first fluid A, consisting of a liquid phase, by the separator 4.

[0043] During a step E3, the second fraction A2 of the first fluid A is evacuated, for example out of the first heat exchanger module 2a.

[0044] During a step E4, the first fraction A1 of the first fluid A is injected into a first circulation channel 50 of a body 3 of a second heat exchanger module 2b.

[0045] Numerous modifications can be made to the heat exchanger assembly, the heat exchanger module and the process without going beyond the scope of this presentation.

Claims

1. A heat exchanger module (2) comprising: - a body (3) comprising at least two sheets (31, 32), each sheet (31, 32) being rolled up into a spiral around the same principal axis (X), the sheets including a first sheet (31) and a second sheet (32) delimiting between them a first circulation channel (50) of a first fluid (A) and a second circulation channel (51) of a second fluid (B), separate from the first circulation channel (50), the first sheet (31) and the second sheet (32) having edges (310, 311) defining a first face of the body (3) and a second face of the body (3), opposite the first face, the first face and the second face extending transversally to the principal axis (X), the first face having first inlet openings (24) to allow circulation of the first fluid (A) from the outside of the body (3) towards the first circulation channel (50), and the second face having first outlet openings (25) to allow circulation of the first fluid (A) from the first circulation channel (50) towards the outside of the body (3), characterized by - a separator (4) for receiving the first fluid (A) flowing via the first outlet openings (25), the separator (4) being suitable for letting through a first fraction (A1) of the first fluid (A) towards first inlet openings of another heat exchanger module located below the heat exchanger module, and preventing a second fraction (A2) of the first fluid (A) from reaching the first inlet openings of the other heat exchanger module, the first fraction (A1) of the first fluid containing a gaseous phase, and the second fraction (A2) of the first fluid consisting of a liquid phase.

2. The heat exchanger module (2) according to claim 1, wherein the separator (4) comprises a passage allowing circulation of the first fraction of the first fluid towards first inlet openings of the other heat exchanger module, and a first partition wall (41) having a first collection surface arranged for receiving the first fluid (A) originating from the first outlet openings (25), the first collection surface being oriented relative to the principal axis (X) for guiding the first fraction (A1) of the first fluid (A) by gravity while moving the second fraction (A2) of the first fluid (A) away from the passage.

3. The heat exchanger module (2) according to claim 2, wherein the first collection surface is oriented relative to the principal axis (X) for guiding the second fraction (A2) of the first fluid (A) by gravity towards an outlet pipe of the first fluid.

4. The heat exchanger module according to any one of claims 2 or 3, wherein the first partition wall (41) has a conical shape, having an axis combined with the principal axis (X).

5. The heat exchanger module according to claim 4, wherein the passage comprises a passage opening (43) located at an apex of the cone.

6. The heat exchanger module according to any one of claims 2 to 5, wherein the separator (4) comprises a second partition wall (42) arranged to prevent the first fraction (A1) of the first fluid (A) originating from the first outlet openings (25) from reaching the passage.

7. The heat exchanger module according to claim 6, wherein the second partition wall (42) has a second collection surface oriented relative to the principal axis (X) for guiding the first fraction (A1) of the first fluid (A) by gravity towards the first collection surface.

8. The module according to any one of claims 6 or 7, wherein the second partition wall (42) has a conical shape having an axis combined with the principal axis (X).

9. The heat exchanger module according to any one of claims 1 to 8, comprising an inlet pipe (6) for injecting the second fluid (B) from the outside of the body towards the second circulation channel (51) and a first outlet pipe (8) for discharging the second fluid (B) from the second circulation channel (51) towards the outside of the body (3).

10. The heat exchanger module according to any one of claims 1 to 9, comprising a nozzle (10) for spraying a cleaning product in the first fluid (A) at the point where the first fluid (A) enters the first circulation channel (50) via the first inlet openings (24).

11. A heat exchanger unit (1) comprising at least two heat exchanger modules (2a, 2b) according to any one of claims 1 to 10, the heat exchanger modules (2a, 2b) being joined together such that the first fraction (A1) of the first fluid (A) containing the gaseous phase originating from a heat exchanger module (2a) of the heat exchanger unit (1) enters the first circulation channel (50) via the first inlet openings (24) of the body (3) of another heat exchanger module (2b) of the heat exchanger unit (1).

12. The heat exchanger unit (1) according to claim 11, wherein each heat exchanger module (2a, 2b) comprises nozzles (10) for spraying a cleaning product in the first fluid (A) at the point where the first fluid (A) enters the first circulation channel (50) via the first inlet openings (24), the heat exchanger unit (1) comprising a control unit configured to control flow and / or temperature of the cleaning product sprayed by each nozzle (10) of each heat exchanger module (2a, 2b) as a function of a difference between pressure of the first fluid (A) as it leaves the first outlet openings (25) and pressure of the first fluid (A) as it enters the first inlet openings (24) of the body of the heat exchanger module.

13. A method for treating a first fluid (A), comprising steps of: - having the first fluid (A) circulate (E1) in a first circulation channel (50) of a body of a first heat exchanger module (2a) according to any one of claims 1 to 10, - separating (E2) the first fluid (50) flowing via the first outlet openings (25) of the body of the first heat exchanger module (2a) into a first fraction (A1) of the first fluid (A) containing a gaseous phase, and into a second fraction (A2) of the first fluid (A) consisting of a liquid phase, - discharging (E3) the second fraction (A2) of the first fluid (A), and - injecting (E4) the first fraction (A1) of the first fluid (A) into a first circulation channel (50) of a body of a second heat exchanger module (2b).

14. The treatment method according to claim 13, wherein the second heat exchanger module (2b) is according to any one of claims 1 to 10.

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