Heat exchange core and LNG vaporizer

Abstract

The application provides a heat exchange core and an LNG vaporizer, and belongs to the technical field of heat exchangers. The heat exchange core is internally provided with a first medium flow channel and a second medium flow channel. The first medium flow channel is used for conveying a medium to be heated, and the second medium flow channel is used for conveying a heating medium. The heating medium in the second medium flow channel and the medium to be heated in the first medium flow channel are heat-exchanged through heat conduction. The second medium flow channel is provided with a first flow channel unit and a second flow channel unit which are stacked and communicated. The first flow channel unit and the second flow channel unit are also heat-exchanged through heat conduction. The heat is transferred through two modes of heat conduction and direct contact, the heat exchange efficiency is good, and the problem of freezing of the heating medium in the flow channel unit adjacent to the first medium flow channel is effectively avoided.

Description

Technical Field

[0001] This invention relates to the field of heat exchanger technology, specifically to a heat exchange core and an LNG vaporizer. Background Technology

[0002] Against the backdrop of environmental and energy issues increasingly dominating global economic development, natural gas, as a clean and efficient energy source, is receiving increasing attention. Liquefied natural gas (LNG) has unique physical properties (-162℃) when stored, requiring heating and vaporization to reach higher temperatures for use by other equipment. The heat source typically uses antifreeze such as ethylene glycol, transferring heat from the antifreeze to the LNG through heat exchange. The vaporizer is a key component in this heat exchange process.

[0003] Existing vaporizers have a heat exchange core that uses two parallel antifreeze channels with different media to exchange heat with liquefied natural gas via thermal conduction. However, since the heat exchange between the two different heating media is only carried out by thermal conduction, the heat exchange efficiency is low and the problem of freezing of the antifreeze channel near the liquefied natural gas cannot be effectively avoided. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is that the heat exchange efficiency between the two layers of different heating media in the existing LNG vaporizer is low, and the antifreeze cannot be effectively prevented from freezing. In order to overcome the above defects, a heat exchange core and an LNG vaporizer are provided.

[0005] To solve the above-mentioned technical problems, the present invention provides a heat exchange core, comprising:

[0006] The first medium flow channel is used to transport the medium to be heated;

[0007] The second medium flow channel is used to transport the heating medium, and the heating medium in the second medium flow channel exchanges heat with the medium to be heated in the first medium flow channel through heat conduction.

[0008] The second medium flow channel has a first flow channel unit and a second flow channel unit stacked together. The first flow channel unit and the second flow channel unit are connected to each other, and the first flow channel unit and the second flow channel unit also exchange heat through heat conduction.

[0009] Optionally, the first flow channel unit and the second flow channel unit of the second medium flow channel are connected in series, and the heating medium inlet and heating medium outlet of the second medium flow channel are both located near the inlet of the first medium flow channel.

[0010] Optionally, the first flow channel unit and the second flow channel unit have at least a radially overlapping section that coincides in the radial projection, and the radially overlapping sections of the first flow channel unit and the second flow channel unit are connected by a plurality of through holes.

[0011] Optionally, the radially overlapping segments of the first flow channel unit and the second flow channel unit are parallel straight line segments.

[0012] Optionally, the radially overlapping segments of the first flow channel unit and the second flow channel unit coincide with the radial projection of at least a portion of the first medium flow channel.

[0013] Optionally, it includes: a plurality of heat exchange plates stacked together, wherein the first medium flow channel and the second medium flow channel are respectively formed through the heat exchange plates.

[0014] Optionally, at least a portion of the heat exchange plate has channels formed on its surface, which together with the surfaces of adjacent heat exchange plates form a first medium flow channel for conveying the medium to be heated, and / or a second medium flow channel for conveying the heating medium.

[0015] This design saves on the volume of the core and reduces the thickness of the heat exchange plate, thereby reducing the heat conduction distance and resulting in higher heat exchange efficiency.

[0016] Optionally, the channel depth is 1 / 5 to 2 / 3 of the heat exchange plate thickness, the bottom wall thickness of the heat exchange plate after removing the channel is 0.1 to 0.5 mm, and the rib width between two adjacent channels on the same heat exchange plate is 0.5 to 10 mm.

[0017] The microchannel structure saves space and is suitable for environments with higher volume requirements.

[0018] Optionally, several heat exchange plates are fixedly connected by diffusion welding.

[0019] The core is made using a vacuum diffusion welding method, resulting in high strength.

[0020] The present invention provides an LNG vaporizer, including the aforementioned heat exchange core.

[0021] The technical solution of the present invention has the following advantages:

[0022] 1. In the heat exchange core of this invention, the medium to be heated in the first medium flow channel exchanges heat with the heating medium in the adjacent first flow channel unit via heat conduction. The heating medium in the first flow channel unit exchanges heat with the heating medium in the second flow channel unit via both heat conduction and direct contact. When the temperature of the heating medium in the first flow channel unit drops significantly, causing local freezing, the higher-temperature heating medium in the second flow channel unit transfers heat to the heating medium in the first flow channel unit through both heat exchange methods. This effectively prevents the freeze from spreading and can also melt the frozen area, thereby preventing the antifreeze from freezing and expanding, which could cause the heat exchanger to leak and fail. The use of both heat conduction and direct contact for heat transfer results in high heat exchange efficiency and effectively avoids the problem of freezing of the heating medium in a flow channel unit adjacent to the first medium flow channel.

[0023] 2. In the heat exchange core of this invention, the first flow channel unit and the second flow channel unit are connected in series. Automated freezing can be achieved using only one heating medium, simplifying external control, resulting in a simpler structure, improved safety and reliability, and cost savings. The heating medium inlet and outlet of the second medium flow channel are both located near the inlet of the first medium flow channel, ensuring a large temperature difference between the medium to be heated and the heating medium, leading to high heat exchange efficiency. The heating medium enters from the first flow channel unit and flows out from the second flow channel unit. Partial convective heat exchange occurs between the first medium flow channel and a portion of the medium in the adjacent second medium flow channel. At least a portion of the medium in the first flow channel unit and at least a portion of the medium in the second flow channel unit also undergoes convective heat exchange, resulting in high heat exchange efficiency.

[0024] 3. The heat exchange core of the present invention has a radially overlapping section between the first flow channel unit and the second flow channel unit, which at least partially overlaps in radial projection. The radially overlapping sections of the first and second flow channel units are connected by a plurality of through holes. The arrangement of the radially overlapping section shortens the heat conduction distance and improves the heat exchange efficiency. The connection between the radially overlapping sections by a plurality of through holes allows the heating medium in the first flow channel unit to flow directly to the outlet of the second flow channel unit through the through holes, shortening the direct contact heat exchange distance, which is shorter than the distance of the series flow channels, thus improving the heat exchange efficiency and more directly preventing the freezing of the heating medium in the second medium flow channel.

[0025] 4. In the heat exchange core of the present invention, the radially overlapping sections of the first and second flow channel units coincide with the radial projection of at least a portion of the first medium flow channel. This shortens the heat conduction distance between the first and second medium flow channels, resulting in high heat exchange efficiency.

[0026] 5. The heat exchange core of the present invention includes multiple heat exchange plates stacked together, and the first medium flow channel and the second medium flow channel are respectively formed through the heat exchange plates. Using multiple heat exchange plates to form the first medium flow channel and the second medium flow channel simplifies manufacturing, and the number of heat exchange plates can be changed according to actual needs, thus providing better adaptability.

[0027] 6. In the heat exchange core of the present invention, at least a portion of the heat exchange plates have channels formed on their surfaces. These channels, together with the surfaces of adjacent heat exchange plates, form a first medium flow channel for conveying the medium to be heated, and / or a second medium flow channel for conveying the heating medium. The channels forming the medium flow channels on the heat exchange plates reduce the volume of the core and the thickness of the heat exchange plates between adjacent medium flow channels, thereby reducing the heat conduction distance and resulting in higher heat exchange efficiency.

[0028] 7. In the heat exchange core of this invention, the channel depth is 1 / 5-2 / 3 of the heat exchange plate thickness, the bottom wall thickness of the heat exchange plate after removing the channels is 0.1-0.5mm, and the rib width between adjacent channels on the same heat exchange plate is 0.5-10mm. The use of a small-sized microchannel structure saves core volume and is suitable for environments with higher requirements for core volume.

[0029] 8. In this invention, several heat exchange plates in the heat exchange core are fixedly connected by diffusion welding. The core is manufactured using vacuum diffusion welding, resulting in high strength. Attached Figure Description

[0030] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0031] Figure 1 This is a flow diagram of the heat exchange medium in an embodiment of the present invention;

[0032] Figure 2 This is a schematic diagram of the first flow channel unit in an embodiment of the present invention;

[0033] Figure 3 for Figure 2 Enlarged view of part A;

[0034] Figure 4 This is a perspective view of the heat exchange core in an embodiment of the present invention;

[0035] Figure 5 for Figure 4 Enlarged view of part B;

[0036] Figure 6This is a perspective view of the first plate in an embodiment of the present invention;

[0037] Figure 7 for Figure 6 Enlarged view of part C;

[0038] Figure 8 This is a perspective view of the second plate in an embodiment of the present invention;

[0039] Figure 9 for Figure 8 Enlarged view of part D;

[0040] Figure 10 This is a perspective view of the third plate in an embodiment of the present invention;

[0041] Figure 11 for Figure 10 Enlarged view of part E;

[0042] Figure 12 This is another heat exchange medium flow diagram of the heat exchange unit in an embodiment of the present invention;

[0043] Explanation of reference numerals in the attached drawings: 1. First medium flow channel; 2. Second medium flow channel; 21. First flow channel unit; 211. First intermediate straight section; 212. First inlet baffle section; 213. First outlet baffle section; 22. Second flow channel unit; 221. Second intermediate straight section; 222. Second inlet baffle section; 223. Second outlet baffle section; 3. Heat exchange plate; 31. First plate body; 32. Second plate body; 321. Through hole; 322. First connecting hole; 33. Third plate body; 331. Second connecting hole; 4. Side plate. Detailed Implementation

[0044] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0046] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0047] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0048] Example 1

[0049] like Figure 1 As shown, this embodiment provides a heat exchange core, which includes a first medium flow channel 1 and a second medium flow channel 2. The first medium flow channel 1 is used to transport the medium to be heated, and the second medium flow channel 2 is used to transport the heating medium. The heating medium in the second medium flow channel 2 exchanges heat with the medium to be heated in the first medium flow channel 1 through heat conduction. The second medium flow channel 2 has a first flow channel unit 21 and a second flow channel unit 22 stacked together. The first flow channel unit 21 and the second flow channel unit 22 are connected, and the first flow channel unit 21 and the second flow channel unit 22 also exchange heat through heat conduction.

[0050] When the aforementioned heat exchange core is used in an LNG vaporizer, the medium to be heated is -160℃ cryogenic liquefied natural gas, and the heating medium is antifreeze, which is 50℃ ethanol or heat transfer oil. The -160℃ liquefied natural gas in the first medium flow channel 1 exchanges heat with the antifreeze in the adjacent first flow channel unit 21. The antifreeze in the first flow channel unit 21 exchanges heat with the antifreeze in the second flow channel unit 22 through both heat conduction and direct contact. When the temperature of the antifreeze in the first flow channel unit 21 drops significantly, causing local freezing, the antifreeze in the second flow channel unit 22, which has a higher temperature, transfers heat to the antifreeze in the first flow channel unit 21 through both heat conduction and direct contact. This results in high heat exchange efficiency, effectively preventing the freeze from spreading and melting the frozen area, thus preventing the antifreeze from freezing and expanding, which could cause the heat exchanger to leak and fail.

[0051] like Figure 1As shown, in the heat exchange core provided in this embodiment, the first flow channel unit 21 and the second flow channel unit 22 are connected in series. Automated freezing can be achieved using only one heating medium, simplifying external control, resulting in a simpler structure, greater safety and reliability, and cost savings. The second medium flow channel 2 has a heating medium inlet and a heating medium outlet, both located near the inlet of the first medium flow channel 1. With this arrangement, the liquefied natural gas at the inlet of the first medium flow channel 1 has the lowest temperature, while the antifreeze at the inlet of the heating medium has the highest temperature. When the antifreeze at the outlet of the heating medium exchanges heat with the liquefied natural gas at the inlet of the first medium flow channel 1, a significant drop in the temperature of the antifreeze at the outlet can cause localized freezing. The higher-temperature antifreeze at the inlet of the heating medium is transferred to the frozen area at the outlet of the heating medium via heat conduction through the heat exchange plate 3, preventing the freezing from expanding and simultaneously melting the frozen area, thus avoiding heat exchanger leakage and failure due to freezing expansion. Figure 1 In the diagram, t represents the heating medium inlet, w represents the heating medium outlet, x represents the inlet of the first medium flow channel 1, and z represents the outlet of the first medium flow channel.

[0052] like Figure 1 As shown, in the heat exchange core provided in this embodiment, the first flow channel unit 21 and the second flow channel unit 22 have a radially overlapping section that at least partially overlaps in radial projection. This arrangement shortens the heat conduction and heat transfer distance between the fluid in the first flow channel unit 21 and the fluid in the second flow channel unit 22, as well as the flow distance of the heating medium.

[0053] like Figure 2 and Figure 3 As shown, in the heat exchange core provided in this embodiment, a plurality of through holes 321 are provided on the radially overlapping section of the first flow channel unit 21 and the second flow channel unit 22. These holes are used to connect the radially overlapping section of the first flow channel unit 21 and the second flow channel unit 22, allowing the high-temperature liquid at the inlet of the first flow channel unit 21 to flow quickly to the outlet of the second flow channel unit 22 through the through holes 321. This results in high heat exchange efficiency and more direct prevention of freezing, leading to more efficient heat transfer. Alternatively, as an alternative implementation, the first flow channel unit 21 and the second flow channel unit 22 may not have a radially overlapping section or through holes 321. Direct connection of the heating medium between the middle section of the first flow channel unit 21 and the second flow channel unit 22 is not required; instead, other methods of connection can be used in other sections, such as through external pipes.

[0054] like Figure 1As shown, in the heat exchange core provided in this embodiment, the radially overlapping sections of the first flow channel unit 21 and the second flow channel unit 22 are parallel straight lines. The radially overlapping sections of the first flow channel unit 21 and the second flow channel unit 22 coincide with the radial projection of a portion of the first medium flow channel 1, shortening the heat conduction and heat transfer distance and making the heat exchange more efficient. Alternatively, as an alternative implementation, the radially overlapping sections of the first flow channel unit 21 and the second flow channel unit 22 can be curved sections.

[0055] like Figure 4 and Figure 5 As shown, in the heat exchange core provided in this embodiment, the heat exchange core includes a plurality of heat exchange plates 3 stacked together, and the first medium flow channel 1 and the second medium flow channel 2 are respectively formed through the heat exchange plates 3.

[0056] like Figure 1 , Figure 7 , Figure 9 and Figure 11 As shown, in the heat exchange core provided in this embodiment, channels are formed on the surface of the heat exchange plate 3. These channels can be arranged in parallel rows, and the number of channels can be adjusted according to usage requirements. The channels, together with the surfaces of adjacent heat exchange plates 3, form a first medium flow channel 1 for transporting liquefied natural gas and a second medium flow channel 2 for transporting the heating medium. Through this arrangement, the channels formed by slotting on the heat exchange plate 3 result in a compact space, reducing the volume of the heat exchange core and decreasing the heat transfer distance between the stacked flow channels, thus improving the heat conduction speed. As an alternative implementation, the first medium flow channel 1 and the second medium flow channel 2 can be formed in different ways. For example, the second medium flow channel 2 can be formed within the heat exchange plate 3. Alternatively, the first medium flow channel 1 or the second medium flow channel 2 can be directly formed inside the heat exchange plate 3. The second medium flow channel 2 includes multiple flow channel units, which can be formed simultaneously on one heat exchange plate 3, or one flow channel unit can be formed on each heat exchange plate 3.

[0057] It should be noted that in the heat exchange core provided in this embodiment, the channel depth is 1 / 5 to 2 / 3 of the thickness of the heat exchange plate 3. The thickness of the bottom wall of the heat exchange plate 3, excluding the thickness of the channel, i.e., the thickness of the thin wall surrounding the channel, is 0.1mm to 0.5mm. Since the heat exchange plate 3 is very thin, the thermal resistance of the material can be ignored. The rib width between two adjacent channels on the same heat exchange plate 3 is 0.5-10mm. The cross-sectional shape of the channel can be semi-circular, rectangular, inverted triangular, or other shapes. The distance between the channel and the edge of the heat exchange plate 3 is adjusted according to the size of the heat exchange plate 311 and the required heat exchange.

[0058] Specifically, when the channel cross-section is semi-circular, half of the channel diameter is 1 / 5 to 2 / 3 of the thickness of the heat exchange plate 3; when the channel cross-section is rectangular, the depth of the rectangular channel is 1 / 5 to 2 / 3 of the thickness of the heat exchange plate 3, and the length and width of the rectangular channel can be adjusted according to the process and heat exchange requirements.

[0059] In the heat exchange core provided in this embodiment, the heat exchange plate 3 can be made of various materials such as stainless steel, titanium, aluminum, or various alloys. Several heat exchange plates 3 are fixedly connected by vacuum diffusion welding, resulting in high pressure resistance and reliability of the heat exchange core. Alternatively, several heat exchange plates 3 can also be fixedly connected using other conventional welding methods.

[0060] In the heat exchange core provided in this embodiment, such as Figure 6 and Figure 7 As shown, the first medium flow channel 1 is a straight flow channel, formed by the straight channels opened on the heat exchange plate 3 and the plate surface of the adjacent heat exchange plate 3; as Figure 8 and Figure 9 As shown, the first flow channel unit 21 in the second medium flow channel 2 is a Z-shaped flow channel, formed by the Z-shaped channels opened on the heat exchange plate 3 and the plate surface of the adjacent heat exchange plate 3; as Figure 10 and Figure 11 As shown, the second flow channel unit 22 is a U-shaped flow channel, which is formed by the U-shaped channel opened on the heat exchange plate 3 and the plate surface of the adjacent heat exchange plate 3.

[0061] In the heat exchange core provided in this embodiment, such as Figure 8 As shown, the first flow channel unit 21 includes a first intermediate straight section 211 and a first inlet deflector section 212 and a first outlet deflector section 213 located at both ends of the first intermediate straight section 211. Figure 10 As shown, the second flow channel unit 22 includes a second intermediate straight section 221 and a second inlet baffle section 222 and a second outlet baffle section 223 located at both ends of the second intermediate straight section 221. The first intermediate straight section 211 of the first flow channel unit 21, the second intermediate straight section 221 of the second flow channel unit 22, and the first medium flow channel 1 overlap in radial projection to form a radially overlapping section. This arrangement shortens the heat conduction distance between the first medium flow channel 1, the first flow channel unit 21, and the second flow channel unit 22, thereby improving the heat exchange efficiency.

[0062] In the heat exchange core provided in this embodiment, such as Figure 6 As shown, the heat exchange plate 3 with straight channels is the first plate 31, and the straight channels are symmetrically distributed in the center on the first plate 31; as Figure 8 As shown, the heat exchange plate 3 with Z-shaped channels is the second plate 32, as... Figure 10 As shown, the heat exchange plate 3 with the U-shaped channel is the third plate 33. (As...) Figure 4As shown, it also includes a side plate 4, which is a solid metal block. The second plate 32, the third plate 33 and the first plate 31 are stacked in sequence to form a heat exchange unit. After several heat exchange units are stacked together, a side plate 4 is added to the top and bottom, and the heat exchange core is made in a vacuum diffusion furnace.

[0063] In the heat exchange core provided in this embodiment, such as Figure 8 As shown, a first connecting hole 322 is formed on the second plate 32, and the outlet of the first flow channel unit 21 is connected to the first connecting hole 322; as Figure 10 As shown, a second connecting hole 331 is opened on the third plate 33, and the inlet of the second flow channel unit 22 is connected to the second connecting hole 331; the first connecting hole 322 and the second connecting hole 331 are aligned, and the outlet of the first flow channel unit 21 is connected to the inlet of the second flow channel unit 22 opened on the adjacent third plate 33 through the first connecting hole 322, so that the antifreeze enters from the inlet of the first flow channel unit 21 and flows into the second flow channel unit 22 through the first connecting hole 322 and the second connecting hole 331 at the outlet of the first flow channel unit 21, and then flows out from the outlet of the second flow channel unit 22.

[0064] In the heat exchange core provided in this embodiment, such as Figures 8-11 As shown, both the first flow channel unit 21 and the second flow channel unit 22 include multiple flow channels. The heating medium flows and converges in the multiple flow channels into the first connecting hole 322 and the second connecting hole 331, and then flows from the second connecting hole 331 into the multiple flow channels of the second flow channel unit 22. Through the mixing of fluids during the convergence process, the temperature of the fluids in the multiple flow channels becomes uniform, thereby making the heat exchange plate 3 heat up evenly, avoiding deformation caused by uneven temperature of the heat exchange plate 3, and improving the heat exchange effect.

[0065] As an alternative implementation, the second connecting hole 331 can also be replaced by a connecting groove, which is aligned with the first connecting hole 322 and connected to the inlet of the second flow channel unit 22. The heating medium flows from the first flow channel unit 21 into the first connecting hole 322 and the connecting groove, and then flows from the connecting groove into the second flow channel unit 22.

[0066] like Figure 12 As shown, in an alternative implementation, the second plate 32 is adjacent to the first plate 31, and the third plate 33 is adjacent to the second plate 32. The second plate 32 is located between the first plate 31 and the third plate 33. The heating medium flows in from the channel of the third plate 33, and flows out from the channel of the second plate 32 through the first connecting hole 322 and the second connecting hole 331.

[0067] like Figure 12As shown, t is the antifreeze inlet, u is the outlet of the Z-shaped channel, v is the inlet of the U-shaped channel, w is the antifreeze outlet, x is the liquefied natural gas inlet, and z is the liquefied natural gas outlet.

[0068] As an alternative implementation, a core can be integrally formed, with the first medium flow channel 1 and the second medium flow channel 2 formed within the core. Alternatively, a core with other structures and shapes can be used, as long as the first medium flow channel 1 and the second medium flow channel 2 can be formed.

[0069] Example 2

[0070] This invention provides an LNG vaporizer, including the heat exchange core as described in Example 1. The first medium flow channel 1 in the heat exchange core is used to transport -160℃ cryogenic liquefied natural gas, and the second medium flow channel 2 is used to transport antifreeze. The antifreeze can be 50℃ ethanol or heat transfer oil.

[0071] In the LNG vaporizer of this embodiment, the -160℃ cryogenic liquefied natural gas in the first medium flow channel 1 exchanges heat with the antifreeze in the adjacent first flow channel unit 21 via thermal conduction. The antifreeze in the first flow channel unit 21 exchanges heat with the antifreeze in the second flow channel unit 22 via both thermal conduction and direct contact. When the temperature of the antifreeze in the first flow channel unit 21 drops significantly, causing local freezing, the antifreeze in the second flow channel unit 22, with its higher temperature, transfers heat to the antifreeze in the first flow channel unit 21 simultaneously through the heat exchange plate 3. This results in high heat exchange efficiency, effectively preventing the freeze from spreading and melting the frozen area, thus preventing the antifreeze from freezing and expanding, which could cause the heat exchanger to leak and fail. Furthermore, the first flow channel unit 21 and the second flow channel unit 22 are connected in series, allowing for automated freezing using only one type of antifreeze, eliminating the need for external control, simplifying the structure, improving safety and reliability, and saving costs.

[0072] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A heat exchange core, characterized in that, include: The first medium flow channel (1) is used to transport the medium to be heated, wherein the medium to be heated is liquefied natural gas; The second medium flow channel (2) is used to transport the heating medium, which is antifreeze. The heating medium in the second medium flow channel (2) and the medium to be heated in the first medium flow channel (1) exchange heat through heat conduction. The second medium flow channel (2) has a first flow channel unit (21) and a second flow channel unit (22) stacked together. The first flow channel unit (21) and the second flow channel unit (22) are connected in series. The first flow channel unit (21) and the second flow channel unit (22) have a radially overlapping section that at least partially overlaps in the radial projection. The radially overlapping sections are connected by a plurality of through holes (321) to realize heat conduction heat transfer and direct contact heat transfer between the first flow channel unit (21) and the second flow channel unit (22). The heating medium inlet and heating medium outlet of the second medium flow channel (2) are both located near the inlet of the first medium flow channel (1).

2. The heat exchange core according to claim 1, characterized in that, The radial overlap segments of the first flow channel unit (21) and the second flow channel unit (22) are parallel straight line segments.

3. The heat exchange core according to claim 1, characterized in that, The radially overlapping segments of the first flow channel unit (21) and the second flow channel unit (22) coincide with the radial projection of at least a portion of the first medium flow channel (1).

4. The heat exchange core according to any one of claims 1-3, characterized in that, include: Multiple heat exchange plates (3) are stacked, and the first medium flow channel (1) and the second medium flow channel (2) are formed by the heat exchange plates (3).

5. The heat exchange core according to claim 4, characterized in that, At least a portion of the heat exchange plate (3) has channels formed on its surface, which together with the surfaces of adjacent heat exchange plates (3) form a first medium flow channel (1) for conveying the medium to be heated, and / or a second medium flow channel (2) for conveying the heating medium.

6. The heat exchange core according to claim 5, characterized in that, The depth of the channel is 1 / 5 to 2 / 3 of the thickness of the heat exchange plate (3). The bottom wall thickness of the heat exchange plate (3) after removing the channel is 0.1-0.5 mm. The width of the rib between two adjacent channels on the same heat exchange plate (3) is 0.5-10 mm.

7. The heat exchange core according to claim 4, characterized in that, Several heat exchange plates (3) are fixedly connected by diffusion welding.

8. An LNG vaporizer, characterized in that, Includes the heat exchange core as described in any one of claims 1-7.

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