Heat exchanger for high-temperature-difference fused salt and water

Abstract

The invention relates to the technical field of heat exchangers, in particular to a high-temperature-difference fused salt and water heat exchanger. The heat exchanger for the high-temperature-difference fused salt and the water specifically comprises a shell pass and a tube pass, the shell pass comprises a shell barrel and a plurality of isolation sleeves, the isolation sleeves are located in the shell barrel, a plurality of annular runners are formed between every two adjacent isolation sleeves, the annular runners are communicated in series through gaps in the end of the shell barrel, and the high-temperature molten salt is located in the annular runners and flows from the annular runner of the outer ring to the annular runner of the inner ring; the tube pass comprises a water inlet end, a plurality of heat exchange tubes and a steam outlet end, the two ends of each heat exchange tube are connected with the water inlet end and the steam outlet end respectively, the heat exchange tubes are spirally wound in the annular flow channel, and heat exchange water enters the heat exchange tubes through the water inlet end and exchanges heat with the high-temperature fused salt in the annular flow channel to form steam which is discharged from the steam outlet end; and the flowing direction of the high-temperature fused salt is opposite to that of the heat exchange water. The heat exchanger has the advantages of no structural constraint and high heat exchange efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of heat exchangers, and in particular to a heat exchanger between molten salt and water at a high temperature difference. Background Art

[0002] High-temperature molten salt energy storage technology is an efficient way of energy storage, which uses the sensible heat of molten salt at high temperature to store thermal energy. This technology has many advantages, including high energy storage density, high thermal stability, low corrosion and environmental friendliness. Molten salt energy storage technology can be widely used in solar thermal power generation, peak and frequency regulation of thermal power units, heating and waste heat recovery.

[0003] The design of the heat exchanger is one of the key technologies in the molten salt heat storage system. It not only takes into account the heat transfer efficiency, but also the corrosiveness of the molten salt and the problem of solidification and blockage caused by the molten salt when the temperature changes. Therefore, the design of the molten salt heat exchanger has become a research hotspot. By optimizing the design and operation methods, the thermal efficiency and stability of the system can be improved, which is of great significance for promoting the commercialization and large-scale application of molten salt energy storage technology.

[0004] High-temperature molten salt-water steam heat exchanger technology is an effective method to convert the heat stored in molten salt into water steam under high temperature conditions. This technology is often used in solar thermal power generation, nuclear power generation and industrial heating systems because it can operate at a lower pressure while providing a higher temperature, thereby improving the thermal efficiency of the system.

[0005] Increasing the heat storage temperature of molten salt can not only increase the heat capacity of molten salt per unit mass and reduce the consumption of molten salt; according to the second law of thermodynamics, it can also improve the thermal efficiency of the thermal system, which is the development direction for improving the thermal efficiency of energy storage units in the future. Increasing the heat storage temperature of molten salt will bring problems such as material corrosion, high temperature creep, structural thermal stress, and thermal expansion to the molten salt-water / water steam heat exchanger. Increasing the heat storage temperature of molten salt also requires increasing the water side pressure that receives heat, which requires higher structural strength.

[0006] Currently, the commonly used high-temperature molten salt-water / steam heat exchangers are traditional structures such as shell and tube heat exchangers. Due to structural constraints, they cannot withstand the large thermal expansion and thermal stress caused by high temperature differences.

[0007] Therefore, in view of the shortcomings of the prior art, a heat exchanger of molten salt and water with a high temperature difference is provided. Summary of the invention

[0008] In order to overcome the deficiencies of the prior art, the present invention provides a heat exchanger between molten salt and water with a high temperature difference, aiming to solve the problem that the structure is constrained and cannot withstand the large thermal expansion and thermal stress caused by the high temperature difference.

[0009] In order to achieve the above object, the present invention adopts the following technical solutions:

[0010] A heat exchanger for molten salt and water with a high temperature difference, comprising: a shell side and a tube side;

[0011] The shell side includes a shell body and a plurality of isolation sleeves, wherein the plurality of isolation sleeves are located inside the shell body, the shell body and the plurality of isolation sleeves are coaxially arranged, and a plurality of annular flow channels are formed between the adjacent two, and the plurality of annular flow channels are connected in series through the gap at the end of the shell body, and the high-temperature molten salt is located in the annular flow channels, and the high-temperature molten salt flows from the annular flow channels of the outer circle to the annular flow channels of the inner circle;

[0012] The tube pass includes a water inlet, a plurality of heat exchange tubes and a steam outlet. Both ends of the heat exchange tube are connected to the water inlet and the steam outlet respectively. The heat exchange tube is spirally wound in the annular flow channel. The exchange water enters the heat exchange tube through the water inlet to perform heat exchange with the high-temperature molten salt in the annular flow channel to form steam and then is discharged from the steam outlet.

[0013] The flow direction of the high-temperature molten salt is opposite to the flow direction of the hot water.

[0014] As a further improvement of the technical solution of the present invention, it also includes an end plate, which connects the shell side and the tube side, and is fixedly connected to the shell cylinder. The end plate is provided with a plurality of through holes for the heat exchange tubes and the molten salt outlet pipe to pass through.

[0015] As a further improvement of the technical solution of the present invention, the shell side also includes a molten salt inlet pipe and a molten salt outlet pipe, the molten salt inlet pipe is fixedly connected to the top of the shell cylinder, the molten salt inlet pipe and the molten salt outlet pipe are both connected to the annular flow channel, and the molten salt outlet pipe passes through the end plate.

[0016] As a further improvement of the technical solution of the present invention, the shell side also includes an annular plate, which is located at the end of the shell cylinder and is used to connect the shell cylinder and the isolation sleeve.

[0017] As a further improvement of the technical solution of the present invention, the shell side further includes a positioning block, the positioning block includes a first positioning block and a second positioning block, the annular plate includes a first annular plate and a second annular plate, and the isolation sleeve further includes an inner sleeve, a first intermediate sleeve, a second intermediate sleeve and a third intermediate sleeve;

[0018] The first annular plate is used to connect the shell cylinder and the second intermediate sleeve, the second annular plate is used to connect the second intermediate sleeve and the inner sleeve, the first positioning block and the first intermediate sleeve are located between the inner sleeve and the second intermediate sleeve, and the second positioning block and the third intermediate sleeve are located between the shell cylinder and the second intermediate sleeve.

[0019] As a further improvement of the technical solution of the present invention, the shell side also includes an inner bottom plate, and both ends of the inner sleeve are fixedly connected to the inner bottom plate.

[0020] As a further improvement of the technical solution of the present invention, the water inlet end includes a water inlet pipe and a water collecting pipe, the water inlet pipe is connected to the water collecting pipe, and the water collecting pipe is connected to a plurality of the heat exchange tubes.

[0021] As a further improvement of the technical solution of the present invention, the steam outlet end includes a steam outlet pipe and a steam collecting pipe, the steam outlet pipe is connected to the steam collecting pipe, and the steam collecting pipe is connected to a plurality of the heat exchange tubes.

[0022] As a further improvement of the technical solution of the present invention, it also includes a fixed support and a sliding support, the fixed support is fixedly connected to the outer wall of the shell cylinder, and the sliding support is slidably connected to the outer wall of the shell cylinder.

[0023] As a further improvement of the technical solution of the present invention, the shell side also includes a sewage outlet, the sewage outlet is located below the shell cylinder, and the sewage outlet is connected to the annular flow channel of the outer ring.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] In the heat exchanger of high temperature difference molten salt and water of the present invention, a plurality of annular flow channels connected in series are arranged in the shell side, and the high temperature molten salt flows from the annular flow channel of the outer circle to the annular flow channel of the inner circle. The heat exchange tube is spirally wound in the annular flow channel, and can expand freely in the axial direction without constraint. The hot water enters the heat exchange tube through the water inlet end and exchanges heat with the high temperature molten salt in the annular flow channel to form steam, which is then discharged from the steam outlet end. The flow direction of the high temperature molten salt is opposite to that of the hot water. The high temperature molten salt is gradually cooled during the flow process, releasing heat. The whole process reverse flow mode maximizes the effective heat transfer temperature difference, thereby improving the heat exchange efficiency of the heat exchanger. The heat exchanger of high temperature difference molten salt and water of the present invention has the characteristics of being free from structural constraints and having high heat exchange efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The technology of the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments:

[0027] Figure 1 is a cross-sectional view of a heat exchanger of a molten salt and water with a high temperature difference according to the present invention;

[0028] Figure 2 Schematic diagram of the structure of the heat exchanger of high temperature difference molten salt and water of the present invention;

[0029] Figure 3 It is a cross-sectional view of a tube pass in a heat exchanger of a molten salt and water with a high temperature difference according to the present invention;

[0030] Figure 4 It is a cross-sectional view of the shell side of the heat exchanger between high temperature difference molten salt and water of the present invention.

[0031] In the figure:

[0032] 11. Shell body; 12. Isolation sleeve; 13. Molten salt inlet pipe; 14. Molten salt outlet pipe; 151. First annular plate; 152. Second annular plate; 161. First positioning block; 162. Second positioning block; 171. Inner sleeve; 172. First intermediate sleeve; 173. Second intermediate sleeve; 174. Third intermediate sleeve; 18. Inner bottom plate; 19. Drain port; 20. Temperature measuring hole;

[0033] 21. Water inlet end; 211. Water inlet pipe; 212. Water collecting pipe; 22. Several heat exchange pipes; 23. Steam outlet end; 231. Steam outlet pipe; 232. Steam collecting pipe;

[0034] 3. End plate;

[0035] 41. Fixed bearing; 42. Sliding bearing. DETAILED DESCRIPTION

[0036] The following will be combined with the embodiments and drawings to clearly and completely describe the concept, specific structure and technical effects of the present invention, so as to fully understand the purpose, scheme and effect of the present invention. It should be noted that the embodiments in this application and the features in the embodiments can be combined with each other without conflict. The same reference numerals used throughout the drawings indicate the same or similar parts.

[0037] It should be noted that, unless otherwise specified, when a feature is referred to as being "fixed" or "connected" to another feature, it may be directly fixed or connected to the other feature, or it may be indirectly fixed or connected to the other feature. In addition, the descriptions of up, down, left, right, etc. used in the present invention are only relative to the relative positional relationship of the components of the present invention in the drawings.

[0038] Reference Figures 1 to 4 , a heat exchanger of molten salt and water with a high temperature difference, a shell side and a tube side;

[0039] In one embodiment, the shell side includes a shell body 11 and a plurality of isolation sleeves 12, the plurality of isolation sleeves 12 are located inside the shell body 11, the shell body 11 and the plurality of isolation sleeves 12 are coaxially arranged, and a plurality of annular flow channels are formed between adjacent ones, the plurality of annular flow channels are connected in series through the gap at the end of the shell body 11, the high-temperature molten salt is located in the annular flow channel, and the high-temperature molten salt flows from the annular flow channel of the outer circle to the annular flow channel of the inner circle; the tube side includes a water inlet end 21, a plurality of heat exchange tubes 22 and a steam outlet end 23, the two ends of the heat exchange tubes are respectively connected to the water inlet end 21 and the steam outlet end 23, the heat exchange tubes are spirally wound in the annular flow channel, the hot water enters the heat exchange tube through the water inlet end 21, exchanges heat with the high-temperature molten salt in the annular flow channel to form steam, and then is discharged from the steam outlet end 23; the flow direction of the high-temperature molten salt is opposite to the flow direction of the hot water. Preferably, the inlet temperature of the high-temperature molten salt is 650°C, the outlet temperature of the high-temperature molten salt is 230°C, the maximum temperature difference is 420°C, and the tube outlet is superheated steam of 10MPa. Preferably, the cross-section of the annular flow channel is an annular cylindrical chamber. The spirally wound heat exchange tube can expand freely in the axial direction without constraint, and the structure can withstand high temperature difference. The number and length of the heat exchange tubes can be adjusted according to the actual heat load requirements to achieve the working requirements of high-temperature molten salt with small flow and large temperature difference and high temperature difference heat exchange.

[0040] Among them, by setting a number of annular flow channels in series in the shell side, the high-temperature molten salt flows from the annular flow channel of the outer circle to the annular flow channel of the inner circle, and the heat exchange tube is spirally wrapped in the annular flow channel, and can expand freely in the axial direction without constraints. The hot water enters the heat exchange tube through the water inlet end 21 and exchanges heat with the high-temperature molten salt in the annular flow channel to form steam and is discharged from the steam outlet end 23. The flow direction of the high-temperature molten salt is opposite to the flow direction of the hot water. The high-temperature molten salt is gradually cooled during the flow process and releases heat. The full-process reverse flow method maximizes the effective heat transfer temperature difference and improves the heat exchange efficiency of the heat exchanger. The heat exchanger of the high temperature difference molten salt and water has the characteristics of being free from structural constraints and high heat exchange efficiency.

[0041] In one embodiment, the heat exchanger further includes an end plate 3, which connects the shell side and the tube side, is fixedly connected to the shell cylinder 11, and is provided with a plurality of through holes for the heat exchange tubes and the molten salt outlet pipe 14 to pass through.

[0042] In one embodiment, the shell side also includes a molten salt inlet pipe 13 and a molten salt outlet pipe 14. The molten salt inlet pipe 13 is fixedly connected to the top of the shell cylinder 11. The molten salt inlet pipe 13 and the molten salt outlet pipe 14 are both connected to the annular flow channel. The molten salt outlet pipe 14 passes through the end plate 3.

[0043] In one embodiment, the shell side also includes an annular plate and an inner bottom plate 18. The annular plate is located at the end of the shell cylinder 11. The annular plate is used to connect the shell cylinder 11 and the isolation sleeve 12. The two ends of the inner sleeve 171 are fixedly connected to the inner bottom plate 18 so that the high-temperature molten salt fluid can be confined in the annular flow channel. A ventilation hole with a diameter of about 8 mm must be opened on the inner bottom plate 18 on the side not in contact with the high-temperature molten salt (right side) so that the air cavity in the inner sleeve 171 can communicate with the external atmosphere.

[0044] In one embodiment, the shell side also includes a positioning block and a temperature measuring hole 20, which are respectively located on the two end surfaces of the annular plate, the positioning block includes a first positioning block 161 and a second positioning block 162, the annular plate includes a first annular plate 151 and a second annular plate 152, and the isolation sleeve 12 also includes an inner sleeve 171, a first intermediate sleeve 172, a second intermediate sleeve 173 and a third intermediate sleeve 174; the first annular plate 151 is used to connect the shell cylinder 11 and the second intermediate sleeve 173, the second annular plate 152 is used to connect the second intermediate sleeve 173 and the inner sleeve 171, the first positioning block 161 and the first intermediate sleeve 172 are located between the inner sleeve 171 and the second intermediate sleeve 173, and the second positioning block 162 and the third intermediate sleeve 174 are located between the shell cylinder 11 and the second intermediate sleeve 173. One end of the first intermediate sleeve 172 is connected to the end plate 3 , and the other end is connected to the first positioning block 161 . One end of the third intermediate sleeve 174 is connected to the end plate 3 , and the other end is connected to the second positioning block 162 .

[0045] In one embodiment, the water inlet end 21 includes a water inlet pipe 211 and a water collecting pipe 212, the water inlet pipe 211 is connected to the water collecting pipe 212, and the water collecting pipe 212 is connected to a plurality of heat exchange pipes 22. The steam outlet end 23 includes a steam collecting pipe 232 and a steam outlet pipe 231, the steam outlet pipe 231 is connected to the steam collecting pipe 232, and the steam collecting pipe 232 is connected to a plurality of heat exchange pipes 22. The heat exchange pipe connected to the water collecting pipe 212 is located in the inner ring annular flow channel, and the heat exchange pipe connected to the steam collecting pipe 232 is located in the outer ring annular flow channel.

[0046] In one embodiment, the heat exchanger further comprises a fixed saddle support and a sliding saddle support, wherein the fixed saddle support is fixedly connected to the outer wall of the shell cylinder 11, and the sliding saddle support is slidably connected to the outer wall of the shell cylinder 11. The function of the sliding saddle support is to make the thermal expansion of the heat exchanger unconstrained during the cold start heating process and eliminate thermal stress.

[0047] In one embodiment, the shell side further includes a sewage outlet 19, which is located below the shell cylinder 11 and is connected to the annular flow channel of the outer ring.

[0048] For other details of the heat exchanger between high temperature difference molten salt and water described in the present invention, please refer to the prior art and will not be described in detail here.

[0049] The above are only preferred embodiments of the present invention and are not intended to limit the present invention in any form. Therefore, any modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the technical solution of the present invention are still within the scope of the technical solution of the present invention.

[0050] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0051] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

Claims

1. A heat exchanger between molten salt and water with a high temperature difference, characterized in that: include: Shell side and tube side; The shell side includes a shell cylinder and a plurality of isolation sleeves, wherein the plurality of isolation sleeves are located inside the shell cylinder, and a plurality of annular flow channels are formed between adjacent two of the shell cylinders, and the plurality of annular flow channels are connected in series through the gaps at the ends of the shell cylinder, and the high-temperature molten salt is located in the annular flow channels, and the high-temperature molten salt flows from the annular flow channels of the outer circle to the annular flow channels of the inner circle; The tube pass includes a water inlet, a plurality of heat exchange tubes and a steam outlet. Both ends of the heat exchange tube are connected to the water inlet and the steam outlet respectively. The heat exchange tube is spirally wound in the annular flow channel. The exchange water enters the heat exchange tube through the water inlet to perform heat exchange with the high-temperature molten salt in the annular flow channel to form steam and then is discharged from the steam outlet. The flow direction of the high-temperature molten salt is opposite to the flow direction of the hot water.

2. A heat exchanger of molten salt and water with a high temperature difference according to claim 1, characterized in that: It also includes an end plate, which connects the shell side and the tube side, is fixedly connected to the shell cylinder, and is provided with a plurality of through holes for the heat exchange tubes and the molten salt outlet pipe to pass through.

3. A heat exchanger of molten salt and water with a high temperature difference according to claim 2, characterized in that: The shell side also includes a molten salt inlet pipe and a molten salt outlet pipe, the molten salt inlet pipe is fixedly connected to the top of the shell cylinder, the molten salt inlet pipe and the molten salt outlet pipe are both connected to the annular flow channel, and the molten salt outlet pipe passes through the end plate.

4. The heat exchanger of a molten salt and water with a high temperature difference according to claim 1, characterized in that: The shell side also includes an annular plate, which is located at the end of the shell cylinder and is used to connect the shell cylinder and the isolation sleeve.

5. A heat exchanger of molten salt and water with a high temperature difference according to claim 4, characterized in that: The shell side further includes a positioning block, the positioning block includes a first positioning block and a second positioning block, the annular plate includes a first annular plate and a second annular plate, and the isolation sleeve further includes an inner sleeve, a first intermediate sleeve, a second intermediate sleeve and a third intermediate sleeve; The first annular plate is used to connect the shell cylinder and the second intermediate sleeve, the second annular plate is used to connect the second intermediate sleeve and the inner sleeve, the first positioning block and the first intermediate sleeve are located between the inner sleeve and the second intermediate sleeve, and the second positioning block and the third intermediate sleeve are located between the shell cylinder and the second intermediate sleeve.

6. A heat exchanger of molten salt and water with a high temperature difference according to claim 5, characterized in that: The shell side also includes an inner bottom plate, and both ends of the inner sleeve are fixedly connected to the inner bottom plate.

7. The heat exchanger of molten salt and water with a high temperature difference according to claim 1, characterized in that: The water inlet end includes a water inlet pipe and a water collecting pipe, the water inlet pipe is connected to the water collecting pipe, and the water collecting pipe is connected to a plurality of the heat exchange tubes.

8. The heat exchanger of molten salt and water with a high temperature difference according to claim 1, characterized in that: The steam outlet end comprises a steam outlet pipe and a steam collecting pipe, the steam outlet pipe is connected to the steam collecting pipe, and the steam collecting pipe is connected to a plurality of the heat exchange pipes.

9. The heat exchanger of molten salt and water with a high temperature difference according to claim 1, characterized in that: It also includes a fixed support and a sliding support, wherein the fixed support is fixedly connected to the outer wall of the shell cylinder, and the sliding support is slidably connected to the outer wall of the shell cylinder.

10. The heat exchanger of molten salt and water with a high temperature difference according to claim 1, characterized in that: The shell side also includes a sewage outlet, which is located below the shell cylinder and is connected to the annular flow channel of the outer ring.

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