Double-layer boiler heating surface structure based on molten salt thermal buffering

Abstract

The invention discloses a double-layer boiler heating surface structure based on fused salt thermal buffering, which comprises a normal pressure heating layer and a high pressure heating layer, the high pressure heating layer is positioned in the normal pressure heating layer, a fused salt thermal buffering layer is arranged between the normal pressure heating layer and the high pressure heating layer, and the structure can ensure the safe operation of the heating surface when the load of a unit rapidly changes.

Description

Technical Field

[0001] The invention belongs to the technical field of thermal power generation, and relates to a double-layer boiler heating surface structure based on molten salt thermal buffering. Background Art

[0002] The heating surface of a boiler refers to: the fuel burns in the furnace, and the heat of its flame and flue gas is constantly absorbed and transferred to water, steam and air through some intermediate medium surfaces, and these intermediate medium surfaces are called boiler heating surfaces. In normal operation of the boiler system, it is subject to fluctuations in coal type and quality, various wind disturbances, and rapid load increases and decreases. When the heat exchange between the furnace radiation and flue gas convection and the boiler heating surface and the heat exchange between the heating surface and the working medium do not match, it is easy to cause the wall temperature of the heating surface to be high. In addition, with the continuous increase in the capacity of new energy power generation, more and more coal-fired power needs to participate in peak regulation. The internal pressure and external temperature of superheaters, reheaters, etc. need to withstand rapid changes, which seriously affects the life of the heating surfaces of the boiler. In severe cases, pipe bursts of the heating surfaces occur frequently, which can easily lead to non-stop accidents and affect the safe and stable operation of the boiler unit. With the rapid development of various new energy power generation, it is inevitable that traditional thermal power generating units play the role of peak regulation of the power grid.

[0003] After searching the prior art with the publication number CN102269396A, a boiler heating surface arrangement structure is disclosed. The specific disclosed technical feature is that at least two different boiler heating surfaces are arranged in parallel at the same section of the flue gas temperature area in the independent flue of the boiler; the at least two different boiler heating surfaces are boiler heating surfaces located at different positions in the same steam-water flow of the boiler, or boiler heating surfaces located in different steam-water flows of the boiler; the at least two different boiler heating surfaces are arranged in the same section of the flue gas temperature area in the independent flue of the boiler in a cross-parallel form. The at least two different boiler heating surfaces are arranged in the same section of the flue gas temperature area in the independent flue of the boiler in a front-to-back parallel form. The at least two different boiler heating surfaces are arranged in the same section of the flue gas temperature area in the independent flue of the boiler in a left-to-right parallel form. The at least two different boiler heating surfaces are arranged in the same section of the flue gas temperature area in the independent flue of the boiler in a combination of at least two of the cross-parallel, front-to-back parallel, and left-to-right parallel arrangement forms. The effect is that it arranges different heating surfaces in the same or different steam-water processes in the same flue gas temperature area of ​​the boiler flue, which can make full use of the heat transfer temperature difference of the boiler heating surface, improve the heat absorption efficiency of the boiler heating surface, and ultimately improve the heat exchange efficiency. The existing technology uses multiple heating surfaces, arranged in different positions, and undertakes different steam-water processes, but it still cannot solve the problem that the internal pressure and external temperature of the superheater, reheater, etc. need to withstand rapid changes, which seriously affects the life of each heating surface of the boiler. In severe cases, the heating surface bursts frequently. Therefore, when designing the heating surface of the existing thermal power generating unit, the safe operation of the heating surface when the unit load changes rapidly should be considered to ensure the safe and stable operation of the boiler unit under long-term peak-shaving operation. However, the existing technology does not provide a technical solution for how to solve the above problems. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a double-layer boiler heating surface structure based on molten salt thermal buffering, which can ensure the safe operation of the heating surface when the unit load changes rapidly.

[0005] To achieve the above-mentioned purpose, the double-layer boiler heating surface structure based on molten salt thermal buffering described in the present invention includes a normal pressure heating layer and a high pressure heating layer. The high pressure heating layer is located inside the normal pressure heating layer, and a molten salt thermal buffer layer is arranged between the normal pressure heating layer and the high pressure heating layer.

[0006] As a further improvement of the double-layer boiler heating surface structure based on molten salt heat buffering according to the present invention,

[0007] Furthermore, the normal-pressure heating layer includes a plurality of rectangular cavities, wherein a single cavity accommodates a single or multiple tube rows of the high-pressure heating layer.

[0008] Furthermore, the distance between the side wall of the cavity and the outer boundary of the tube row of the high-pressure heating layer is 20 mm.

[0009] Furthermore, a Z-shaped high-temperature molten salt equalizing tube is arranged between two adjacent rows of cavities.

[0010] Furthermore, the angle between the inclined section of the Z-shaped high-temperature molten salt equalizing tube and the horizontal direction is 30°-50°.

[0011] Furthermore, it also includes a high-temperature molten salt overflow pipe and a molten salt buffer bin. A high-temperature molten salt overflow port is provided at the very end of the normal-pressure heating layer. The high-temperature molten salt overflow port is connected to the high-temperature molten salt overflow pipe, and the outlet of the high-temperature molten salt overflow pipe is connected to the molten salt buffer bin.

[0012] Furthermore, the high temperature molten salt overflow pipe is distributed with an upward inclination of 20°.

[0013] Furthermore, a pressure relief valve is arranged on the molten salt buffer bin.

[0014] Furthermore, the molten salt thermal buffer layer plays the role of transferring heat, the normal-pressure heating layer is subjected to high temperature, its own gravity and the gravity of the molten salt; the high-pressure heating layer is subjected to the high pressure of the working fluid and the heat transfer of the boiling molten salt.

[0015] The double-layer boiler heating surface structure based on molten salt heat buffering of the present invention comprises a high-temperature molten salt overflow pipe, a molten salt buffer bin, a normal-pressure heating layer and a high-pressure heating layer, wherein the high-pressure heating layer is located within the normal-pressure heating layer, and a molten salt heat buffer layer is provided between the normal-pressure heating layer and the high-pressure heating layer;

[0016] The normal pressure heating layer includes a plurality of rectangular cavities, wherein a single cavity can accommodate a single or multiple tube rows of the high pressure heating layer, and a Z-shaped high temperature molten salt equalizing tube is arranged between two adjacent rows of cavities;

[0017] A high-temperature molten salt overflow port is provided at the end of the normal-pressure heating layer, and the high-temperature molten salt overflow port is connected to a high-temperature molten salt overflow pipe, and an outlet of the high-temperature molten salt overflow pipe is connected to a molten salt buffer bin.

[0018] The present invention discloses a boiler, which includes a double-layer boiler heating surface structure based on molten salt thermal buffering, wherein the double-layer boiler heating surface structure based on molten salt thermal buffering includes a normal-pressure heating layer and a high-pressure heating layer, wherein the high-pressure heating layer is located within the normal-pressure heating layer, and a molten salt thermal buffer layer is arranged between the normal-pressure heating layer and the high-pressure heating layer.

[0019] The present invention has the following beneficial effects:

[0020] The double-layer boiler heating surface structure based on molten salt heat buffering described in the present invention comprises a normal-pressure heating layer and a high-pressure heating layer during specific operation. The high-pressure heating layer is located within the normal-pressure heating layer, and a molten salt heat buffer layer is arranged between the normal-pressure heating layer and the high-pressure heating layer. The traditional single-layer heating surface that bears both temperature and pressure is optimized and designed to be a double-layer heating surface composed of a normal-pressure heating layer, a molten salt heat buffer layer and a high-pressure heating layer. The normal-pressure heating layer only needs to withstand high temperature, its own gravity and the gravity of molten salt; the high-pressure heating layer only needs to withstand the high pressure of the working fluid and the heat transfer of boiling molten salt, so that when the load of the unit fluctuates rapidly, the metal temperature of the heating surface in the high-pressure heating layer will not overheat, thereby extending the life of the heating surface and ensuring the safe and stable operation of the boiler unit.

[0021] Furthermore, a Z-shaped high-temperature molten salt equalizing tube is arranged between two adjacent rows of cavities. The angle between the inclined section of the Z-shaped high-temperature molten salt equalizing tube and the horizontal direction is 30°-50°. By setting the Z-shaped high-temperature molten salt equalizing tube, the high-temperature molten salt inside the normal pressure heating layer can be homogenized, and at the same time, the disturbance of the flue gas flow passing through the heating surface can be enhanced, thereby avoiding the formation of a flue gas corridor and enhancing the heat exchange between the flue gas and the heating surface.

[0022] Furthermore, the distance between the side wall of the cavity and the outer boundary of the tube row of the high-pressure heating layer is 20 mm to allow for expansion of the high-pressure heating layer.

[0023] Furthermore, a pressure relief valve is arranged on the molten salt buffer tank. When the pressure in the molten salt buffer tank is greater than 1.5 atmospheres, the pressure relief valve opens to avoid the risk of explosion due to excessive pressure in the normal pressure heating layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0025] Figure 1 is a cross-sectional view of the present invention;

[0026] Figure 2 It is a structural diagram of the present invention;

[0027] Figure 3 for Figure 2 Cross-sectional view along the AA direction.

[0028] Among them, 1 is the boiler furnace, 2 is the normal pressure heating layer, 3 is the high pressure heating layer, 4 is the high temperature molten salt overflow pipe, 5 is the molten salt buffer bin, 6 is the pressure relief valve, 7 is the molten salt thermal buffer layer, and 8 is the Z-shaped high temperature molten salt equalizing pipe. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] In the description of the present invention, it should be understood that the terms “include” and “comprises” indicate the presence of described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or collections thereof.

[0031] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0032] It should be further understood that the term "and / or" used in the present specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes these combinations. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in the present invention generally indicates that the associated objects are in an "or" relationship.

[0033] It should be understood that, although the terms first, second, third, etc. may be used to describe preset ranges, etc. in the embodiments of the present invention, these preset ranges should not be limited to these terms. These terms are only used to distinguish preset ranges from each other. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0034] The word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)", depending on the context.

[0035] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention described and shown in the drawings here can usually be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0036] Various structural schematic diagrams of the embodiments disclosed in the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0037] Embodiment 1

[0038] refer to Figure 2 The double-layer boiler heating surface structure based on molten salt heat buffering described in the present invention is characterized in that it includes a high-temperature molten salt overflow pipe 4, a molten salt buffer bin 5, a normal-pressure heating layer 2 and a high-pressure heating layer 3, the high-pressure heating layer 3 is located in the normal-pressure heating layer 2, and a molten salt heat buffer layer 7 is arranged between the normal-pressure heating layer 2 and the high-pressure heating layer 3; the normal-pressure heating layer 2 contains a plurality of rectangular cavities, wherein a single cavity can accommodate a single or multiple pipe rows of the high-pressure heating layer 3, and a Z-shaped high-temperature molten salt equalizing pipe 8 is arranged between two adjacent rows of cavities; a high-temperature molten salt overflow port is arranged at the very end of the normal-pressure heating layer 2, and the high-temperature molten salt overflow port is connected to the high-temperature molten salt overflow pipe 4, and the outlet of the high-temperature molten salt overflow pipe 4 is connected to the molten salt buffer bin 5.

[0039] It should be noted that the double-layer heating surface in the present invention includes a normal-pressure heating layer 2, a molten salt thermal buffer layer 7 and a high-pressure heating layer 3, wherein the normal-pressure heating layer 2 only needs to withstand high temperature, its own gravity and the gravity of the molten salt; the high-pressure heating layer 3 only needs to withstand the high pressure of the working fluid and the heat transfer of the boiling molten salt, so that when the load of the unit fluctuates rapidly, the high-pressure heating layer 3 will not have the phenomenon of over-temperature of the heating surface metal temperature. The corresponding loads are borne by different heating layers to extend the life of the heating surface and ensure the safe and stable operation of the boiler unit.

[0040] Embodiment 2

[0041] refer to Figure 1 , Figure 2 and Figure 3 The double-layer boiler heating surface structure based on molten salt heat buffering described in the present invention includes a normal-pressure heating layer 2 and a high-pressure heating layer 3. The high-pressure heating layer 3 is located in the normal-pressure heating layer 2. A molten salt heat buffer layer 7 is arranged between the normal-pressure heating layer 2 and the high-pressure heating layer 3. The molten salt heat buffer layer 7 plays a role in efficiently transferring heat. The normal-pressure heating layer 2 only needs to withstand high temperature, its own gravity and the gravity of molten salt; the high-pressure heating layer 3 only needs to withstand the high pressure of the working fluid and the heat transfer of boiling molten salt, without the risk of overheating.

[0042] As an embodiment of the present invention, along the flue gas flow on the horizontal flue of the boiler, the normal-pressure heating layer 2 includes a plurality of rectangular cavities, wherein a single cavity can accommodate a single or multiple tube rows of the high-pressure heating layer 3, and the distance between the side wall of the cavity and the outer boundary of the tube row of the high-pressure heating layer 3 is 20 mm to allow the high-pressure heating layer 3 to expand.

[0043] As an embodiment of the present invention, a Z-shaped high-temperature molten salt equalizing tube 8 is arranged between two adjacent rows of cavities. The angle between the inclined section of the Z-shaped high-temperature molten salt equalizing tube 8 and the horizontal direction is 30°-50°. It can promote the homogenization of the high-temperature molten salt inside the normal pressure heating layer 2 while promoting flue gas disturbance and avoiding the formation of flue gas corridors. In addition, the angle between the inclined section of the Z-shaped high-temperature molten salt equalizing tube 8 and the horizontal direction is adjusted according to the size of the installation position.

[0044] As an embodiment of the present invention, a high-temperature molten salt overflow port is provided at the very end of the normal-pressure heating layer 2, and the high-temperature molten salt overflow port is connected to the high-temperature molten salt overflow pipe 4, and the high-temperature molten salt overflow pipe 4 is inclined upward at 20°, and the outlet of the high-temperature molten salt overflow pipe 4 is connected to the molten salt buffer bin 5.

[0045] As an embodiment of the present invention, a pressure relief valve 6 is arranged on the molten salt buffer bin 5. When the pressure in the molten salt buffer bin 5 is greater than 1.5 atmospheres, the pressure relief valve 6 opens to avoid the risk of explosion due to excessive pressure in the normal pressure heating layer 2.

[0046] As an embodiment of the present invention, the boiling point of the molten salt in the molten salt thermal buffer layer 7 is the long-term allowable operating temperature T-30° C. of the high-pressure heating layer 3 .

[0047] Principle and working process of the present invention:

[0048] The present invention optimizes the design of the traditional single-layer heating surface that can bear both temperature and pressure into a double-layer heating surface composed of a normal-pressure heating layer 2, a molten salt thermal buffer layer 7 and a high-pressure heating layer 3. The normal-pressure heating layer 2 only needs to withstand high temperature, its own gravity and the gravity of the molten salt; the high-pressure heating layer 3 only needs to withstand the high pressure of the working fluid and the heat transfer of the boiling molten salt, so that the high-pressure heating layer 3 will not have the phenomenon of over-temperature of the heating surface metal temperature when the unit load fluctuates rapidly, thereby extending the service life of the heating surface and ensuring the safe and stable operation of the boiler unit. At the same time, a Z-shaped high-temperature molten salt equalizing tube 8 is arranged between two adjacent rows of cavities. The angle between the inclined section on the Z-shaped high-temperature molten salt equalizing tube 8 and the horizontal direction is 30-50°, which can promote the homogenization of the high-temperature molten salt inside the normal-pressure heating layer 2 while promoting flue gas disturbance and avoiding the formation of flue gas corridors. By setting the Z-shaped high-temperature molten salt equalizing tube 8, the homogenization of the high-temperature molten salt inside the normal-pressure heating layer 2 can be promoted, and at the same time, the disturbance of the flue gas when it flows through the heating surface can be enhanced, avoiding the formation of flue gas corridors and enhancing the heat exchange between the flue gas and the heating surface.

[0049] In summary, the present invention can ensure that under various working conditions and when the boiler load changes drastically, each heating surface of the boiler operates within its allowable temperature range, avoiding the risk of tube burst caused by overheating of the heating surface, and realizing safe, stable, efficient and environmentally friendly operation of the boiler unit under variable load and various conditions.

[0050] Embodiment 3

[0051] The present embodiment discloses a boiler, which includes a double-layer boiler heating surface structure based on molten salt thermal buffering, wherein the double-layer boiler heating surface structure based on molten salt thermal buffering includes a normal-pressure heating layer 2 and a high-pressure heating layer 3, wherein the high-pressure heating layer 3 is located within the normal-pressure heating layer 2, and a molten salt thermal buffer layer 7 is arranged between the normal-pressure heating layer 2 and the high-pressure heating layer 3.

[0052] Specifically, the normal-pressure heating layer 2 includes a plurality of rectangular cavities, wherein a single cavity contains a single or multiple tube rows of the high-pressure heating layer 3; the distance between the side wall of the cavity and the outer boundary of the tube row of the high-pressure heating layer 3 is 20 mm; a Z-shaped high-temperature molten salt equalizing pipe 8 is arranged between two adjacent rows of cavities; the angle between the inclined section of the Z-shaped high-temperature molten salt equalizing pipe 8 and the horizontal direction is 30°-50°; it also includes a high-temperature molten salt overflow pipe 4 and a molten salt buffer bin 5, and the normal-pressure heating layer 2 A high-temperature molten salt overflow port is provided at the very end, and the high-temperature molten salt overflow port is connected with the high-temperature molten salt overflow pipe 4, and the outlet of the high-temperature molten salt overflow pipe 4 is connected with the molten salt buffer bin 5; the high-temperature molten salt overflow pipe 4 is inclined upward at 20°; a pressure relief valve 6 is arranged on the molten salt buffer bin 5; the molten salt thermal buffer layer 7 plays the function of transferring heat, and the normal-pressure heating layer 2 is subjected to high temperature, its own gravity and the gravity of the molten salt; the high-pressure heating layer 3 is subjected to the high pressure of the working fluid and the heat transfer of the boiling molten salt.

[0053] It should be noted that the boiler described in the present invention adopts a double-layer boiler heating surface structure based on molten salt heat buffering, which can effectively improve the safety and life of the boiler and ensure the safe and stable operation of the boiler unit under long-term peak-shaving operation conditions.

[0054] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and disclosure of the invention. This application is intended to cover any variations, uses or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art that are not disclosed by the present invention. The specification and examples are to be considered exemplary only, and the true scope and spirit of the present invention are indicated by the following claims.

[0055] It should be understood that the present invention is not limited to the exact construction that has been described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

[0056] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural change made to the above embodiment based on the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A double-layer boiler heating surface structure based on molten salt heat buffer, characterized in that: It comprises a normal-pressure heating layer (2) and a high-pressure heating layer (3), wherein the high-pressure heating layer (3) is located inside the normal-pressure heating layer (2), and a molten salt heat buffer layer (7) is provided between the normal-pressure heating layer (2) and the high-pressure heating layer (3).

2. The double-layer boiler heating surface structure based on molten salt heat buffer according to claim 1 is characterized in that: The normal-pressure heating layer (2) includes a plurality of rectangular cavities, wherein a single cavity contains a single or multiple tube rows of the high-pressure heating layer (3).

3. The double-layer boiler heating surface structure based on molten salt heat buffer according to claim 2 is characterized in that: The distance between the side wall of the cavity and the outer boundary of the tube row of the high-pressure heating layer (3) is 20 mm.

4. The double-layer boiler heating surface structure based on molten salt heat buffer according to claim 2 is characterized in that: A Z-shaped high-temperature molten salt equalizing pipe (8) is arranged between two adjacent rows of cavities.

5. The double-layer boiler heating surface structure based on molten salt heat buffer according to claim 4 is characterized in that: The angle between the inclined section of the Z-shaped high-temperature molten salt equalizing pipe (8) and the horizontal direction is 30°-50°.

6. The double-layer boiler heating surface structure based on molten salt heat buffer according to claim 1 is characterized in that: It also includes a high-temperature molten salt overflow pipe (4) and a molten salt buffer bin (5); a high-temperature molten salt overflow port is provided at the end of the normal-pressure heating layer (2); the high-temperature molten salt overflow port is connected to the high-temperature molten salt overflow pipe (4); and the outlet of the high-temperature molten salt overflow pipe (4) is connected to the molten salt buffer bin (5).

7. The double-layer boiler heating surface structure based on molten salt heat buffer according to claim 1 is characterized in that: The high-temperature molten salt overflow pipe (4) is distributed with an upward inclination of 20°.

8. The double-layer boiler heating surface structure based on molten salt heat buffer according to claim 1 is characterized in that: A pressure relief valve (6) is arranged on the molten salt buffer bin (5).

9. The double-layer boiler heating surface structure based on molten salt heat buffer according to claim 1 is characterized in that: The molten salt heat buffer layer (7) performs the function of transferring heat, and the normal-pressure heating layer (2) bears high temperature, its own gravity and the gravity of the molten salt; the high-pressure heating layer (3) bears the high pressure of the working fluid and the heat transfer of the boiling molten salt.

10. A double-layer boiler heating surface structure based on molten salt thermal buffer, characterized in that: It comprises a high-temperature molten salt overflow pipe (4), a molten salt buffer bin (5), a normal-pressure heating layer (2) and a high-pressure heating layer (3), wherein the high-pressure heating layer (3) is located inside the normal-pressure heating layer (2), and a molten salt thermal buffer layer (7) is provided between the normal-pressure heating layer (2) and the high-pressure heating layer (3); The normal pressure heating layer (2) includes a plurality of rectangular parallelepiped cavities, wherein a single cavity can accommodate a single or multiple tube rows of the high pressure heating layer (3), and a Z-shaped high temperature molten salt equalizing tube (8) is arranged between two adjacent rows of cavities; A high-temperature molten salt overflow port is provided at the end of the normal-pressure heating layer (2), and the high-temperature molten salt overflow port is connected to a high-temperature molten salt overflow pipe (4), and the outlet of the high-temperature molten salt overflow pipe (4) is connected to a molten salt buffer bin (5).

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