Heat exchanger, cold energy recovery device comprising heat exchanger and modular device comprising heat exchanger

Abstract

The utility model discloses a heat exchanger, a cold energy recovery device comprising the heat exchanger and a modular device.The heat exchanger comprises a plurality of U-shaped sections and connecting parts used for connecting the adjacent U-shaped sections, the U-shaped sections form a first fluid flow path and a second fluid flow path surrounding the first fluid flow path, and the U-shaped sections form a second fluid flow path surrounding the second fluid flow path. The connecting parts are configured to enable the first fluid flow paths and the second fluid flow paths of the adjacent U-shaped sections to be in butt joint respectively, so that in at least one part of the connecting parts, the first fluid flow paths are not surrounded by the second fluid flow paths. The heat exchanger and the cold energy recovery device are compact in structure, complete vaporization can be guaranteed through specific U-shaped section arrangement, and the cold energy utilization efficiency is improved. Therefore, the power consumption of the refrigerating unit of the coolant circulation system is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of cold energy recovery. In particular, it relates to a heat exchanger and a cold energy recovery device. More particularly, it relates to a modular device for converting low-temperature liquid into gaseous state while effectively recovering cold energy using a heat exchanger. BACKGROUND

[0002] The expansion and vaporization of low-temperature liquids such as liquid oxygen, liquid argon, liquid nitrogen, and liquid helium contain a large amount of energy. For example, the boiling point of liquid nitrogen is -195.8°C. On-site nitrogen production requires the use of high-energy consumption production equipment, which is usually far from the use site. Therefore, nitrogen is usually transported to the use site in the form of liquid nitrogen. However, nitrogen is ultimately used in gaseous form, so liquid nitrogen needs to be vaporized. During the phase change of liquid nitrogen into gaseous state through the vaporizer, heat needs to be absorbed, and cold energy is generated. The more nitrogen a factory needs, the more nitrogen it gets, and the more cold energy it releases. Too much cold energy can cause severe icing, frosting, or fogging on the surface of the vaporizer. The common solution used by users is to provide a backup vaporizer to replace the frosted vaporizer. The common problem is that the vaporizer occupies a large space.

[0003] In addition, it cannot be flexibly adjusted according to the user's gas consumption. If the gas consumption increases, the old cold energy recovery device cannot be directly expanded and upgraded, and it can only be completely removed and replaced. If the gas consumption decreases, the excess cold energy will be wasted. Moreover, some heat exchangers that rely only on flange connection at both ends of the prior art are suitable for conventional cooling towers and cannot be used in the case of phase change during heat exchange. CONTENT OF THE INVENTION

[0004] People have been thinking about how to effectively utilize this part of cold energy. Some industrial processes require the use of coolants. This part of the coolant is delivered to the same or different equipment. If the cold energy generated by the expansion and vaporization of low-temperature liquid can be effectively transferred to the coolant, the waste of cold energy can be minimized.

[0005] One of the features of the heat exchanger and cold energy recovery device of the present application is the structural design of the heat exchanger. In particular, a double-pipe heat exchanger is used, with the outer pipe carrying the coolant and the inner pipe carrying the low-temperature liquid (such as liquid oxygen, liquid nitrogen, liquid argon, and liquid helium). The coolant and the low-temperature liquid exchange heat. The low-temperature liquid vaporizes into gas and is supplied to the user. The coolant absorbs cold energy and becomes low-temperature coolant, which is used by the coolant circulation system. This reduces the power consumption of the chiller unit of the coolant circulation system, reducing energy consumption and carbon dioxide emissions.

[0006] The first aspect of the present application provides a heat exchanger, the heat exchanger comprising a plurality of U-shaped segments and connecting portions for connecting adjacent U-shaped segments, wherein the U-shaped segments form first fluid flow paths and second fluid flow paths surrounding the first fluid flow paths, and the connecting portions are configured to abut the first fluid flow paths and the second fluid flow paths of adjacent U-shaped segments respectively, such that in at least a portion of the connecting portions, the first fluid flow paths are not surrounded by the second fluid flow paths.

[0007] Further, the U-shaped segments comprise an outer tube and an inner tube extending axially inside the outer tube, the first fluid (low-temperature liquid) to be vaporized flows in the inner tube to form the first fluid flow paths, and an annular gap is formed between the inner tube and the outer tube, the second fluid (coolant) to be cooled flows in the annular gap to form the second fluid flow paths.

[0008] Further, the connecting portions comprise connecting portion bodies and terminal portions, the connecting portion bodies comprise U-shaped segment connecting ports and terminal portion connecting ports, the U-shaped segment connecting ports are used for connecting the U-shaped segments, and the terminal portion connecting ports are used for connecting the terminal portions.

[0009] Further, the cross-sectional shape of the connecting portion bodies is I-shaped, H-shaped or convex-shaped.

[0010] Further, the terminal portion connecting ports are welded to the terminal portions. The welded joint can be accurately inspected and can ensure proper sealing at low temperatures, without crevice corrosion, and has long-lasting reliability.

[0011] Further, only the first fluid flows in the terminal portions.

[0012] Further, the connecting portion bodies are I-shaped hollow structures. Preferably, at least one end of the hollow structure is connected to the U-shaped segments, such that the first fluid flow paths and the second fluid flow paths extend in the connecting portion bodies, and at least one other end of the hollow structure extends out of the connecting portion bodies and is welded to the terminal portions.

[0013] Further, the connecting portion bodies are formed by welding two tee valves.

[0014] Further, the first fluid and the second fluid flow in the same direction in the heat exchanger.

[0015] Further, the U-shaped segments have integrally formed closed U-shaped ends.

[0016] The second aspect of the present application provides a cold energy recovery device, the cold energy recovery device comprising:

[0017] a low-temperature liquid source;

[0018] a coolant source;

[0019] a heat exchanger for exchanging heat between the cryogenic liquid and the coolant, said heat exchanger comprising a plurality of U-shaped segments and connecting portions for connecting the U-shaped segments, comprising:

[0020] a first fluid inlet, wherein the cryogenic liquid source supplies the cryogenic liquid to the heat exchanger via the first fluid inlet;

[0021] a first fluid outlet, wherein the gas after the cryogenic liquid is vaporized is supplied to a gas usage end via the first fluid outlet;

[0022] a second fluid inlet, wherein the coolant source supplies the coolant to the heat exchanger via the second fluid inlet;

[0023] a second fluid outlet, wherein the heat exchanger supplies the coolant to a coolant usage end via the second fluid outlet.

[0024] Further, the coolant is water or glycol.

[0025] A third aspect of the present application provides a modular device for recovering cryogenic liquid cold energy. The modular device is constructed or modified by adding or removing each set of heat exchangers to achieve full vaporization. The longitudinal cross-section of the heat exchanger in each modular device is substantially constant in height.

[0026] Further, the modular device is arranged in parallel or series by a plurality of said heat exchangers. Multiple modules can be connected together to meet different gas flow requirements. The preferred way is parallel arrangement. That is, the cryogenic liquid and the coolant are proportionally distributed to each heat exchanger, so as not to increase the pressure drop, thereby resulting in higher efficiency.

[0027] Further, the modular device can include a hexahedral box having a length, a width and a height. The box has opposite horizontal top and bottom faces, two opposite vertical end faces, and two opposite vertical side faces. The top and bottom faces of the box are defined by the length and the width of the box. The two vertical end faces of the box are defined by the length and the height of the box. The two vertical side faces of the box are defined by the width and the height of the box. The box encloses at least one chamber having a hexahedral volume within it, the at least one chamber having a length, a width and a height. The chamber includes at least one cold energy recovery device as described above capable of achieving heat exchange, respectively fixing adjacent modular devices.

[0028] Further, at least one common support frame is located on the outer periphery of each modular device, providing process and / or control and / or utility functions. Each modular device can be connected to the common support frame through flanges. For example, the capacity of a group of modular devices means that the (gas) flow of the first fluid outlet is 100 Nm 3 / h~150 Nm3 / h.

[0029] Adding modular devices can increase the ability and / or efficiency of cold energy recovery thereof. Or,

[0030] Removing modular devices can reduce the ability and / or efficiency of cold energy recovery thereof, and / or reduce the volume of the device.

[0031] The tank is made of metal, preferably stainless steel or carbon steel.

[0032] Compared with the prior art, the technical solution provided by the present application has the following advantages:

[0033] 1. The heat exchanger and cold energy recovery device of the present application are compact in structure, and the specific U-shaped segment arrangement can not only ensure complete vaporization, but also improve the cold energy utilization efficiency. Therefore, the power consumption of the refrigerating unit of the coolant circulation system is reduced.

[0034] 2. The cold energy recovery device can be designed in a modular manner, so that the change in gas consumption can be responded to by increasing or reducing the modules. After installation, the configuration of the modules can be adjusted according to the demand of the user end. And it can be quickly disassembled and replaced in the use site. BRIEF DESCRIPTION OF DRAWINGS

[0035] The advantages and spirits of the present application can be further understood through the following detailed description and drawings.

[0036] Figure 1 is a front view of the heat exchanger of the present application.

[0037] Figure 2 is a top view of the heat exchanger of the present application.

[0038] Figure 3 is an axonometric view of the heat exchanger of the present application.

[0039] In the figure: 101 represents a U-shaped segment, 102 represents a connecting part, 1021 represents an end part, 1022 represents a connecting part body, 103 represents a U-shaped segment connecting port, 104 represents an end part connecting port, 105 represents a first fluid inlet, 106 represents a first fluid outlet, 107 represents a second fluid inlet, 108 represents a second fluid outlet, 109 represents an inner tube, and 110 represents an outer tube. DETAILED DESCRIPTION

[0040] The specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. However, the present application should be understood as not being limited to the following described embodiments, and the technical concept of the present application can be implemented in combination with other known technologies or other technologies having the same functions as those known technologies.

[0041] In the following description of specific embodiments, directional terms, such as "front", "back", "left", "right", "outward", "inward", "axial", "radial", etc., are used for convenience only to describe the orientation of the structure and its working mode, and should not be construed as limiting terms.

[0042] In the following description of specific embodiments, it should be understood that the terms "length", "width", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as a limitation on the present application. In addition, when a first structure is described as being positioned "above" or "below" a second structure, this should be understood to mean that the first structure is positioned further away from or closer to the horizontal plane.

[0043] In addition, the terms "first", "second", etc. are only for descriptive purposes and are not intended to indicate or imply relative importance, quantity, or importance, and are not intended to indicate or imply relative importance or implicitly indicate the number of technical features indicated, but only to distinguish one technical feature in the present technical solution from another technical feature. Therefore, the features limited by "first", "second" can explicitly or implicitly include one or more features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specified. Similarly, the limiting language appearing in this text, such as "one", is not intended to limit the quantity, but to describe the technical features that have not appeared in the preceding text. Similarly, the adjectives appearing before the numerals in this text, such as "about", "approximately", generally include the number, and the specific meaning thereof should be understood in conjunction with the context.

[0044] It should be understood that in the present application, "at least one" means one or more, and "multiple" means two or more. "And / or" is used to describe the relationship between the associated objects, which means that there can be three relationships, for example, "A and / or B" can mean: only A, only B, and A and B exist at the same time, where A and B can be singular or plural. The character " / " generally represents an "or" relationship between the preceding and following associated objects. "At least one of the following" or similar expressions means any combination of these items, including any combination of single or multiple items. For example, at least one of a, b, or c, can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0045] In this application, unless specifically stated and limited otherwise, the terms "mounting", "connected", "connected", "fixed" and like terms should be broadly interpreted. For example, it can be fixed connection, or detachable connection, or integrated; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances. "Fixedly connected" or "fixed connection" or "non-actively connected" is understood to mean the connection between two or more structural members is not configured to provide relative movement. An example of a fixed connection is a welded joint or a bolted joint, and in some cases a welded joint and a bolted joint. "Active connection" or "active" or "movable connection" is understood to mean the connection between two or more structural members that allows horizontal and / or vertical relative movement between the members under extreme dynamic loads. Such connections generally do not allow movement under static loads or general dynamic loads (e.g., as applied by light / medium wind).

[0046] Term explanation

[0047] The terms "unit", "piece", "thing" and "module" described in the specification mean a unit for processing at least one function and operation, and can be implemented by a hardware component or a software component and a combination thereof.

[0048] "Upstream" and "downstream" described herein are defined with respect to the intended flow of fluid, with the upstream end corresponding to the end closest to the introduction of fluid into the inlet, and the downstream end corresponding to the end where fluid exits the outlet.

[0049] The terms "high pressure" and "low pressure" mean that high pressure is higher than low pressure, so the difference between the two can be relatively small.

[0050] The terms "high temperature" and "low temperature" mean that high temperature is higher than low temperature, so the difference between the two can be relatively small.

[0051] As used in this article, "heat exchange device," "heat exchanger," "heat exchanger," and "multi-tube heat exchanger" can refer to a double-pipe / tube-in-tube heat exchanger. It involves inserting an inner tube into an outer tube, allowing heat exchange between the fluid flowing within the inner tube and between the inner and outer tubes. A heat exchanger mainly consists of multiple long tubes spaced a certain distance apart and arranged parallel or non-parallel to each other. These long tubes have a flattened, elongated elliptical cross-section in the axial direction. Taking a double-tube heat exchanger as an example, a tube-in-tube heat exchanger includes an inner tube and an outer tube surrounding the outer circumference of the inner tube, forming a flow path between the inner and outer tubes.

[0052] As used herein, fluid refers to a continuous, amorphous substance whose molecules move freely toward each other and tend to take the shape of their container, such as, but not limited to, liquids or gases.

[0053] As used in this article, "cryogenic liquids" are partially liquid during transport due to low or even cryogenic temperatures. These can be liquid nitrogen or liquid argon, hydrogen, helium, neon, methane, and carbon monoxide, etc. Even if a phase change occurs in the cryogenic liquid within the heat exchanger, this article refers to both the cryogenic liquid and the gas produced after the phase change as the first fluid.

[0054] Unless otherwise clearly indicated, each aspect or embodiment defined herein may be combined with any other aspect or embodiment. In particular, any feature indicated as preferred or advantageous may be combined with any other feature indicated as preferred or advantageous.

[0055] like Figure 1 and Figure 3 As shown, the heat exchanger used herein includes multiple U-shaped segments 101 and connecting portions 102 for connecting the U-shaped segments.

[0056] Each U-shaped segment 101 may be the same as or different from each other. For example, the U-shaped segments 101 may differ from each other in terms of length or diameter of one or more tubes. Adjacent U-shaped segments 101 are separated by a gap.

[0057] like Figure 2 As shown, the U-shaped segment 101 includes an inner tube 109 and an outer tube 110 surrounding the outer surface of the inner tube. The inner tube 109 extends axially inside the outer tube 110. In the U-shaped segment 101, the inner tube 109 is inserted into the outer tube 110, that is, the axis of the inner tube 109 and the axis of the outer tube 110 coincide. The inner tube 109 of any U-shaped segment 101 exits from the outer tube 110 of the preceding U-shaped segment 101, passes through the connecting portion 102, and then enters the outer tube 110 of the following U-shaped segment 101, to ensure that at least one section of the inner tube 109 and the outer tube 110 does not involve circling or nesting. As an example, such as Figure 1As shown, the end portion 1021 of the connecting portion 102 is not nested. Exemplarily, this end portion 1021 is equivalent to a section of "bare" inner tube construction. This end portion 1021, which is not nested, facilitates the observation of the vaporization state. If supercooling occurs, frost can form on the end portion 1021. Furthermore, the solder joints of the end portion connecting port 104 are exposed, which facilitates the detection of leaks and the repair of the solder joints.

[0058] The connecting portion body 1022 comprises a U-shaped segment connecting port 103 and an end portion connecting port 104. The U-shaped segment connecting port 103 is used to connect the U-shaped segment 101. The end portion connecting port 104 is used to connect the end portion 1021. The cross-sectional shape of the connecting portion body 1022 is an I-beam shape, an H-shape or a convex shape. Exemplarily, the connecting portion body 1022 can be formed by welding two tee valves.

[0059] The first fluid flow path and the second fluid flow path of the adjacent U-shaped segments 101 are respectively connected by the connecting portion 102. Here, "respectively connected" means that at least a part of the first fluid flow path is not surrounded by the second fluid flow path, but is connected to the first fluid flow path of the next U-shaped segment as an independent flow path. That is, the total axial length of the inner tube in the heat exchanger is greater than the total axial length of the outer tube.

[0060] The U-shaped end of the U-shaped segment 101 is an integrally formed closed end. The U-shaped segment 101 can be bent as a whole while maintaining the coaxiality of the inner tube 109 axis and the outer tube 110 axis, so as to cope with the stress caused by thermal expansion and contraction of the low-temperature liquid. This is because the temperature difference will cause the inner tube to expand along the horizontal axis relative to the outer tube. According to an advantageous design scheme, the inner tube is inserted into the outer tube in the initial state during processing and manufacturing, and then the outer tube is formed. In this way, the end sections of the inner tube and the outer tube are formed in the same shape. In this way, the inner tube and the outer tube have a space for synchronous expansion and contraction, thereby stabilizing and improving the stress of the fluid thermal expansion and contraction. For example, the inner tube of a U-shaped segment with a length of 1.5 meters will generate a cold contraction force of 1 to 4 cm. If a conventional welding or other fixed connection method is used, deformation or cracking is likely to occur.

[0061] The first fluid inlet 105 and the second fluid inlet 107 are arranged at the bottom of the heat exchanger. The first fluid and the second fluid pass through each U-shaped segment 101 from bottom to top, and are led out from the first fluid outlet 106 and the second fluid outlet 108.

[0062] The outer tube 110 and the inner tube 109 are preferably made of metal, in particular steel, in particular stainless steel.

[0063] In the heat exchanger, the low-temperature liquid and the coolant flow in the same direction in the heat exchanger. Moreover, the low-temperature liquid and the coolant both flow from bottom to top. In this way, the gas after vaporization continues to flow along the inner tube 109 to the first fluid outlet 106, and finally reaches thermal equilibrium with the coolant. This is very different from the conventional double-pipe heat exchanger, which presents the form of two fluids flowing in opposite directions.

[0064] The fluids can exchange heat without direct contact with each other. The pipe diameter size of the double pipe is selected according to the processing capacity. The outer pipe with a large pipe diameter is sleeved outside the inner pipe with a small pipe diameter. Both the outer pipe wall and the inner pipe wall are included in the vertical and horizontal cross sections. In this way, the vaporization area can be effectively increased, and the vaporization efficiency can be improved.

[0065] The specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. The embodiments can be throughout the multiple views of the drawings. The same reference signs in the embodiments generally represent the same or corresponding elements. Therefore, the description of the embodiments is incorporated into each other, and the description of the common subject matter of each embodiment is generally not repeated here.

[0066] Take a set of cold energy recovery device modules as an example. The capacity of each set of modular devices represents the (gas) flow rate of the first fluid outlet as 100 Nm 3 / h. Water is used as the coolant to achieve the vaporization of liquid nitrogen while recovering the cold energy in the liquid nitrogen into the water.

[0067] Take a U-shaped segment 101 and a connecting part 102 for connecting the U-shaped segment as an example. The outer pipe 110 is a continuous seamless pipe with a length of 2460 mm, a diameter of 34 mm, and a wall thickness of 2 mm. The inner pipe 109 is a continuous seamless pipe with a diameter of 18 mm, a wall thickness of 2 mm, and a length of 2840 mm. By using the above multiple U-shaped segments 101 and connecting parts 102, a plurality of resistance temperature detectors RTD are surface-mounted to test heat transfer and the minimum required pipe length. It is found that the heat exchanger inner pipe with a total length of 15 to 18 meters can achieve complete vaporization.

[0068] The temperature of the liquid nitrogen at the first fluid inlet 105 is lower than -150℃, and the inlet pressure is about 1.2 MPa. The nitrogen flow rate at the first fluid outlet 106 is 100 Nm 3 / h, the temperature is greater than 7℃, and the outlet pressure is about 1.2 MPa.

[0069] The water flow rate at the second fluid inlet 107 is 2.5 Nm 3 / h, the temperature is about 14℃, and the inlet pressure is about 0.2-0.5 MPa. The water flow rate at the second fluid outlet 108 is 2.5 Nm 3 / h, the temperature is about 7℃, and the outlet pressure is about 0.2-0.5 MPa.

[0070] The heat transfer efficiency can be determined according to the ratio of the energy recovered by the cooling water to the heat generated by the vaporization of nitrogen. Tests show that the heat transfer efficiency of the cold energy recovery device is close to 90%.

[0071] The preferred embodiments described in the specification are only preferred embodiments of the present application, and the above embodiments are only used to illustrate the technical solutions of the present application but not to limit the present application. Any technical solutions obtained by logical analysis, reasoning or limited experiments based on the concept of the present application should be within the scope of the present application.

Claims

1. A heat exchanger, characterized by, The heat exchanger comprises a plurality of U-shaped segments and connecting portions for connecting adjacent U-shaped segments, wherein the U-shaped segments form first fluid flow paths and second fluid flow paths surrounding the first fluid flow paths, and the connecting portions are configured to abut the first fluid flow paths and the second fluid flow paths of adjacent U-shaped segments respectively, so that in at least a portion of the connecting portions, the first fluid flow paths are not surrounded by the second fluid flow paths.

2. The heat exchanger of claim 1, wherein The U-shaped segment comprises an outer tube and an inner tube extending axially inside the outer tube, and a first fluid to be vaporized flows in the inner tube to form the first fluid flow path; an annular gap is formed between the inner tube and the outer tube, and a second fluid to be cooled flows in the annular gap to form the second fluid flow path.

3. The heat exchanger according to claim 1 or 2, characterized in that The connecting portion comprises a connecting portion body and a terminal portion, the connecting portion body comprises a U-shaped segment connecting port and a terminal portion connecting port, the U-shaped segment connecting port is used for connecting the U-shaped segment, and the terminal portion connecting port is used for connecting the terminal portion.

4. The heat exchanger of claim 3, wherein The cross-sectional shape of the connecting portion body is an I-shaped section, an H-shaped section or a convex section.

5. The heat exchanger of claim 3, wherein The terminal portion connecting port is welded to the terminal portion.

6. The heat exchanger of claim 3, wherein Only the first fluid flows in the terminal portion.

7. The heat exchanger according to claim 1 or 2, characterized in that The first fluid and the second fluid flow in the same direction in the heat exchanger.

8. The heat exchanger according to claim 1 or 2, characterized in that The U-shaped segment has an integrally formed closed U-shaped end.

9. A cold energy recovery device characterized by comprising: The cold energy recovery device comprises: a low-temperature liquid source; a coolant source; the heat exchanger of any one of claims 1-8, which exchanges heat between the low-temperature liquid and the coolant, and comprises a plurality of U-shaped segments and connecting portions for connecting the U-shaped segments, and a first fluid inlet, wherein the low-temperature liquid source supplies low-temperature liquid to the heat exchanger through the first fluid inlet; a first fluid outlet, wherein the gas after the low-temperature liquid is vaporized is supplied to a gas use end through the first fluid outlet; a second fluid inlet, wherein the coolant source supplies coolant to the heat exchanger through the second fluid inlet; a second fluid outlet, wherein the heat exchanger supplies the coolant to a coolant use end through the second fluid outlet.

10. A modular device, characterized by The modular device is arranged in parallel or series by a plurality of heat exchangers of any one of claims 1-8, and the modular device is used for recovering cold energy of the low-temperature liquid.

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