Inner cylinder type fused salt heat storage and exchange device and fused salt heat storage steam generation system

Abstract

The invention relates to the technical field of fused salt heat storage, and provides an inner barrel type fused salt heat storage and exchange device which comprises a tank body, a first heat exchange pipeline and a second heat exchange pipeline. The heat transfer inner cylinder is arranged in the tank body, the heat transfer inner cylinder and the tank body are coaxially arranged, and a second heat exchange pipeline is arranged on the cylinder wall of the heat transfer inner cylinder; a first heat storage material is arranged in a space between the interior of the tank body and the exterior of the heat transfer inner cylinder; and the first heating device is inserted into the first heat storage material outside the heat transfer inner barrel in the vertical direction, and the first heating device is used for heating the first heat storage material. The temperature distribution uniformity of the fused salt in the tank in the height direction during heat storage is improved, the heat storage capacity of the fused salt is more utilized, meanwhile, the utilization degree of the heat release capacity of the fused salt of the core layer during heat release is also improved, and the heat storage and release capacity of the fused salt is effectively utilized. The invention further provides a fused salt heat storage steam generation system.

Description

Technical Field

[0001] The present application relates to the technical field of molten salt heat storage, and in particular to an inner cylinder type molten salt heat storage and heat exchange device and a molten salt heat storage steam generation system. Background Art

[0002] At present, there is a molten salt heat storage and heat exchange device, which includes a molten salt tank, an electric heating unit and a heat exchange pipe. The molten salt tank is filled with molten salt, the electric heating unit is used to heat the molten salt, and the heat exchange pipe includes an inlet and an outlet. When the low-temperature fluid enters the heat exchange pipe from the inlet, it will exchange heat with the high-temperature molten salt in the tank through the heat exchange pipe, thereby converting the low-temperature fluid into a high-temperature and high-pressure fluid and discharging it from the outlet of the heat exchange pipe.

[0003] When the molten salt heat storage and heat exchange device is storing heat, the electric heating unit heats the molten salt to melt, and the density of the molten salt decreases as the temperature increases. The higher the temperature of the molten salt, the larger the volume and the smaller the density. As the heating process continues, the molten salt with higher temperature and lower density will rise, while the molten salt with lower temperature and higher density will sink. When the upper molten salt is heated to the highest operating temperature, the electric heating unit stops working, but at this time the temperature of the lower molten salt in the tank is still relatively low. The temperature distribution of the molten salt in the tank is high at the top and low at the bottom, and the heat storage capacity of the molten salt in the tank is not fully utilized.

[0004] When the molten salt heat storage and heat exchange device releases heat, since the heat exchange pipe is arranged close to the periphery of the molten salt, the utilization rate of the molten salt close to the heat exchange pipe (outer molten salt) is higher during heat release, while the heat release capacity of the molten salt far away from the heat exchange pipe (inner core molten salt / core layer molten salt) or the molten salt near the axis of the tank is not fully utilized, resulting in cost waste. Summary of the invention

[0005] In order to solve the above problems, the present application provides an inner cylinder type molten salt heat storage and heat exchange device and a molten salt heat storage steam generation system, which are cleverly designed and simple in structure. The present application improves the uniformity of temperature distribution of the molten salt in the tank in the height direction during heat storage, and makes more use of the heat storage capacity of the molten salt. At the same time, the present application also improves the degree of utilization of the heat release capacity of the core layer molten salt during heat release, so that the heat storage and release capacity of the molten salt are effectively utilized. The technical solutions adopted in the present application are as follows:

[0006] An inner cylinder type molten salt heat storage and heat exchange device, comprising:

[0007] A tank body, wherein a first heat exchange pipe is arranged on the tank wall of the tank body; a heat transfer inner cylinder, wherein the heat transfer inner cylinder is arranged in the tank body and coaxially with the tank body, and a second heat exchange pipe is arranged on the cylinder wall of the heat transfer inner cylinder; a first heat storage material is arranged in the space between the tank body and the outside of the heat transfer inner cylinder; a first heating device, wherein the first heating device is inserted into the first heat storage material outside the heat transfer inner cylinder in a vertical direction, and the first heating device is used to heat the first heat storage material, and the first heat storage material is a molten salt heat storage material. A second heat storage material is arranged in the heat transfer inner cylinder, and the second heat storage material can be a molten salt heat storage material or other heat storage materials.

[0008] The structure of the first heating device heats only the lower part, and does not heat the upper part. During the heating process, the temperature of the molten salt in the lower part of the tank increases and the density decreases. It moves upward through natural convection, which makes the temperature of the molten salt more uniform, the average temperature of the molten salt increases, and the corresponding heat storage will also increase, thereby reducing the use of molten salt and reducing investment costs. In the heat storage stage, the first heating device heats the first heat storage material and transfers the heat to the second heat storage material through the heat transfer inner cylinder. After reaching the set temperature, the temperature distribution inside and outside the heat transfer inner cylinder will tend to be consistent. In the heat release stage, water exchanges heat with the first heat storage material through the first heat exchange pipe, and the second heat exchange pipe exchanges heat with the first heat storage material and the second heat storage material. The second heat exchange pipe is close to the core layer heat storage material, which greatly improves the heat release capacity of the core layer heat storage material, thereby improving the heat release density of the heat storage material.

[0009] In some embodiments, the first heat exchange pipe is disposed on the inner wall of the tank body, and the second heat exchange pipe is disposed on the outer wall of the heat transfer inner cylinder.

[0010] In some embodiments, the first heat exchange pipe is spirally arranged along the height direction of the tank body, the inlet of the first heat exchange pipe is arranged close to the bottom of the tank body, and the outlet of the first heat exchange pipe is arranged close to the top of the tank body; and / or the second heat exchange pipe is spirally arranged along the height direction of the heat transfer inner cylinder, the inlet of the second heat exchange pipe is arranged close to the bottom of the heat transfer inner cylinder, and the outlet of the second heat exchange pipe is arranged close to the top of the heat transfer inner cylinder.

[0011] In some embodiments, the flow cross section of the first heat exchange pipe or the flow cross section of the second heat exchange pipe is in an arch shape.

[0012] In some embodiments, the layout density of the first heat exchange pipe gradually increases from the bottom of the tank body to the top of the tank body along the height direction of the tank body; and / or the layout density of the second heat exchange pipe gradually increases from the bottom of the heat transfer inner cylinder to the top of the heat transfer inner cylinder along the height direction of the heat transfer inner cylinder.

[0013] In some embodiments, a second heat storage material is disposed in the heat transfer inner cylinder. By disposing the second heat storage material in the heat transfer inner cylinder, the heat storage and heat release capacity of the entire device is improved.

[0014] In some embodiments, the first heat storage material is a molten salt heat storage material, and the second heat storage material is a non-molten salt heat storage material.

[0015] In some embodiments, the inner cylinder type molten salt heat storage and heat exchange device further includes a second heating device, which is inserted into the second heat storage material in the heat transfer inner cylinder along a vertical direction.

[0016] In some embodiments, the first heat exchange pipe and the second heat exchange pipe are configured to be switchable between parallel connection and series connection.

[0017] On the other hand, the present application provides a molten salt heat storage steam generation system, which adopts the aforementioned molten salt heat storage and heat exchange device.

[0018] The present application provides an inner-cylinder type molten salt heat storage and heat exchange device and a molten salt heat storage steam generation system, which have at least one of the following beneficial effects:

[0019] 1. The present application provides an inner cylinder type molten salt heat storage and heat exchange device. By setting a heat transfer inner cylinder, when no molten salt heat storage material is set in the heat transfer inner cylinder or a non-molten salt heat storage material is set, on the one hand, the use of molten salt heat storage material can be reduced, and the investment cost can be reduced. On the other hand, the heat transfer inner cylinder plays a role of heat conduction, and the heat transfer inner cylinder can be used to transfer the heat of the molten salt heat storage material located at a high position to the molten salt heat storage material located at a low position, thereby improving the uniformity of the temperature distribution of the molten salt heat storage material in the tank in the height direction during heat storage, so that more use can be made of the heat storage capacity of the molten salt. In addition, by setting a second heat exchange pipe on the cylinder wall of the heat transfer inner cylinder, because the second heat exchange pipe is close to the core layer molten salt, the utilization degree of the heat release capacity of the core layer molten salt during heat release is improved. In this way, by setting the heat transfer inner cylinder and the second heat exchange pipe, the heat storage and release capacity of the molten salt are effectively utilized.

[0020] 2. The present application provides an inner cylinder type molten salt heat storage and heat exchange device, in which the first heat exchange pipe is arranged on the inner wall of the tank body, and the second heat exchange pipe is arranged on the outer wall of the heat transfer inner cylinder, and a molten salt heat storage material is arranged in the space between the inside of the tank body and the outside of the heat transfer inner cylinder. That is to say, most areas of the pipe walls of the first heat exchange pipe and the second heat exchange pipe are in contact with the molten salt heat storage material and can perform heat exchange, thereby ensuring that the heat exchange pipes (the first heat exchange pipe and the second heat exchange pipe) have a large contact area with the molten salt heat storage material, thereby improving the heat exchange efficiency between the heat exchange pipes and the molten salt heat storage material.

[0021] 3. The present application provides an inner tube type molten salt heat storage and heat exchange device, which ensures the heat exchange path length of the heat exchange pipe by designing the heat exchange pipe (the first heat exchange pipe and the second heat exchange pipe) into a spiral shape, so that the fluid in the heat exchange pipe can absorb enough heat from the molten salt heat storage material to obtain the expected temperature and pressure of the fluid. By setting the inlet of the heat exchange pipe close to the bottom of the tank body (or the heat transfer inner tube), and setting the outlet of the heat exchange pipe close to the top of the tank body (or the heat transfer inner tube), the temperature distribution of the molten salt heat storage material in the tank body in the height direction is high at the top and low at the bottom. When the fluid enters the heat exchange pipe, it first exchanges heat with the molten salt with a relatively low temperature at the bottom of the tank body. As the fluid rises in the spiral heat exchange pipe, the fluid gradually exchanges heat with the molten salt with a relatively high temperature at the top of the tank body and gradually heats up, reducing the temperature difference between the fluid and the molten salt in the heat exchange pipe at the same height position, reducing the risk of vibration and abnormal noise in the heat exchange pipe, and improving the safety of the device.

[0022] 4. The present application provides an inner cylinder type molten salt heat storage and heat exchange device. When fluid flows through the heat exchange pipe, the pipe wall of the heat exchange pipe will be subjected to the pressure of the fluid. By designing the flow section of the heat exchange pipe (the first heat exchange pipe and the second heat exchange pipe) to be an arch shape, the pipe wall of the heat exchange pipe can maintain its original shape when subjected to fluid pressure and is not easily deformed, thereby reducing the probability of deformation and leakage of the heat exchange pipe.

[0023] 5. The present application provides an inner cylinder type molten salt heat storage and heat exchange device, which combines the temperature distribution of the molten salt heat storage material in the tank body in the height direction, which is high at the top and low at the bottom. By arranging the heat exchange pipes gradually denser from bottom to top, compared with the uniform arrangement of the heat exchange pipes along the height direction, more heat from the molten salt at the high position in the tank can be absorbed, thereby improving the utilization of the heat release capacity of the molten salt, which is consistent with the distribution characteristic of the molten salt temperature, which is high at the top and low at the bottom.

[0024] 6. The present application provides an inner cylinder type molten salt heat storage and heat exchange device, which improves the heat storage and heat release capacity of the entire device by arranging a second heat storage material in the heat transfer inner cylinder.

[0025] 7. The present application provides an inner cylinder type molten salt heat storage and heat exchange device, which arranges non-molten salt heat storage material in the heat transfer inner cylinder. Compared with the molten salt heat storage material, the volume unit price of the non-molten salt heat storage material is relatively low, which can save costs.

[0026] 8. The present application provides an inner cylinder type molten salt heat storage and heat exchange device. By setting a second heating device in the heat transfer inner cylinder, the second heating device can be used to fully heat the second heat storage material in the heat transfer inner cylinder, thereby improving the utilization of the heat storage capacity of the second heat storage material.

[0027] 9. The present application provides an inner cylinder type molten salt heat storage and heat exchange device, which can improve the ability of the entire device to supply a fluid of a preset temperature and pressure when releasing heat by configuring the first heat exchange pipe and the second heat exchange pipe to be switchable between parallel connection and series connection. For example, when the entire device just starts to release heat, the first heat exchange pipe and the second heat exchange pipe can both independently and efficiently supply a fluid of a preset temperature and pressure. At this time, the first heat exchange pipe and the second heat exchange pipe are connected in parallel. As the heat release proceeds, the temperature of the heat storage material in the device gradually decreases, and one or both of the first heat exchange pipe and the second heat exchange pipe cannot efficiently supply a fluid of a preset temperature and pressure. At this time, the first heat exchange pipe and the second heat exchange pipe can be switched to a series connection. By extending the heat exchange path, it is ensured that the entire device can continue to efficiently supply a fluid of a preset temperature and pressure. Such a design improves the utilization of the heat release capacity of the heat storage material. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The following will explain the preferred implementation mode in a clear and understandable manner in conjunction with the accompanying drawings, and further explain the above characteristics, technical features, advantages and implementation methods of an inner cylinder type molten salt heat storage and heat exchange device and a molten salt heat storage steam generation system:

[0029] Figure 1 It is a structural schematic diagram of an embodiment in which the flow cross section of the heat exchange pipe is in an arch shape;

[0030] Figure 2 It is a structural schematic diagram of an embodiment in which the flow cross section of the heat exchange pipe is a triangle;

[0031] Figure 3 is a structural schematic diagram of an embodiment in which the flow cross section of the heat exchange pipe is a rectangle;

[0032] Figure 4 It is a structural schematic diagram of an embodiment in which the heat exchange pipe gradually becomes denser from bottom to top;

[0033] Figure 5 It is a structural schematic diagram of an embodiment in which heat exchange pipes are provided on both the inner and outer cylinder walls of the heat transfer inner cylinder;

[0034] Figure 6 It is a structural schematic diagram of an embodiment in which a heat exchange pipe is provided on the inner cylinder wall of the heat transfer inner cylinder;

[0035] Figure 7 It is a structural schematic diagram of an embodiment in which a heating device is provided in a heat transfer inner cylinder.

[0036] Description of Figure Numbers:

[0037] Tank body 1, first heat exchange pipe 2, heat transfer inner tube 3, second heat exchange pipe 4, first heating device 5, second heating device 6, heat conduction fins 7. DETAILED DESCRIPTION

[0038] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the specific implementation methods of the present application will be described below with reference to the accompanying drawings. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings and other implementation methods can be obtained based on these drawings without creative work.

[0039] In order to simplify the drawings, only the parts related to the present application are schematically shown in each figure, and they do not represent the actual structure of the product. In addition, in order to simplify the drawings and facilitate understanding, in some figures, only one of the parts with the same structure or function is schematically drawn or marked. In this article, "one" not only means "only one", but also means "more than one".

[0040] It should be further understood that the term “and / or” used in the specification and appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0041] In this document, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0042] In addition, in the description of the present application, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0043] refer to Figure 1-Figure 7 The present application provides an inner cylinder type molten salt heat storage and heat exchange device, comprising: a tank body 1, a first heat exchange pipe 2 is provided on the tank wall of the tank body 1; a heat transfer inner cylinder 3, the heat transfer inner cylinder 3 is arranged in the tank body 1 and coaxially arranged with the tank body 1, and a second heat exchange pipe 4 is provided on the cylinder wall of the heat transfer inner cylinder 3; a first heat storage material is provided in the space between the tank body 1 and the outside of the heat transfer inner cylinder 3; a first heating device 5, the first heating device 5 is inserted into the first heat storage material outside the heat transfer inner cylinder 3 in a vertical direction, and the first heating device 5 is used to heat the first heat storage material.

[0044] It should be noted that the first heat storage material mentioned in this application is a molten salt heat storage material, referred to as molten salt, that is, the molten salt heat storage material and molten salt mentioned below refer to the same substance. The heat transfer inner cylinder 3 can be made of metal material only, or a heat conductive coating is provided on the surface of the metal material. The heat conductive coating can be graphene, high temperature resistant heat conductive coating, etc. The heat transfer inner cylinder 3 can also be made of other heat conductive materials.

[0045] It can be understood that by setting the heat transfer inner cylinder 3, when the molten salt heat storage material is not set in the heat transfer inner cylinder 3 or when the non-molten salt heat storage material is set, on the one hand, the use of the molten salt heat storage material can be reduced, and the investment cost can be reduced. On the other hand, the heat transfer inner cylinder 3 plays a role of heat conduction, and the heat transfer inner cylinder 3 can be used to transfer the heat of the molten salt heat storage material located at a high position to the molten salt heat storage material located at a low position, thereby improving the uniformity of the temperature distribution of the molten salt heat storage material in the tank in the height direction during heat storage, so that the heat storage capacity of the molten salt can be more utilized. In addition, by setting the second heat exchange pipe 4 on the wall of the heat transfer inner cylinder 3, because the second heat exchange pipe 4 is close to the core layer molten salt, the utilization degree of the heat release capacity of the core layer molten salt during heat release is improved. In this way, by setting the heat transfer inner cylinder 3 and the second heat exchange pipe 4, the heat storage and release capacity of the molten salt are effectively utilized.

[0046] refer to Figure 1-Figure 4 , Figure 7 In one embodiment, the first heat exchange pipe 2 is arranged on the inner wall of the tank body 1, and the second heat exchange pipe 4 is arranged on the outer wall of the heat transfer inner tube 3. It can be understood that by arranging the first heat exchange pipe 2 on the inner wall of the tank body 1 and the second heat exchange pipe 4 on the outer wall of the heat transfer inner tube 3, and the molten salt heat storage material is arranged in the space between the inside of the tank body 1 and the outside of the heat transfer inner tube 3, that is, most of the pipe walls of the first heat exchange pipe 2 and the second heat exchange pipe 4 are in contact with the molten salt heat storage material and can exchange heat, ensuring that the heat exchange pipes (the first heat exchange pipe 2 and the second heat exchange pipe 4) have a large contact area with the molten salt heat storage material, thereby improving the heat exchange efficiency between the heat exchange pipes and the molten salt heat storage material.

[0047] In other embodiments, the first heat exchange pipe 2 may also be arranged on the outer wall of the tank body 1, and the second heat exchange pipe 4 may also be arranged on the inner wall of the heat transfer inner tube 3 (refer to Figure 6 ). refer to Figure 5 Heat exchange pipes may also be provided on both the inner and outer tube walls of the heat transfer inner tube 3 to form a second heat exchange pipe 4.

[0048] refer to Figure 1-Figure 7In one embodiment, the first heat exchange pipe 2 is spirally arranged along the height direction of the tank body 1, the inlet of the first heat exchange pipe 2 is arranged near the bottom of the tank body 1, and the outlet of the first heat exchange pipe 2 is arranged near the top of the tank body 1; and / or the second heat exchange pipe 4 is spirally arranged along the height direction of the heat transfer inner cylinder 3, the inlet of the second heat exchange pipe 4 is arranged near the bottom of the heat transfer inner cylinder 3, and the outlet of the second heat exchange pipe 4 is arranged near the top of the heat transfer inner cylinder 3.

[0049] In this embodiment, by designing the heat exchange pipe (the first heat exchange pipe 2 and the second heat exchange pipe 4) to be spiral, the heat exchange path length of the heat exchange pipe is ensured, so that the fluid in the heat exchange pipe can absorb enough heat from the molten salt heat storage material to obtain the fluid of the expected temperature and pressure. By setting the inlet of the heat exchange pipe close to the bottom of the tank body 1 (or the heat transfer inner tube 3), and setting the outlet of the heat exchange pipe close to the top of the tank body 1 (or the heat transfer inner tube 3), the temperature distribution of the molten salt heat storage material in the tank body 1 in the height direction is high at the top and low at the bottom. When the fluid enters the heat exchange pipe, it first exchanges heat with the molten salt with a relatively low temperature at the bottom of the tank body 1. As the fluid rises in the spiral heat exchange pipe, the fluid gradually exchanges heat with the molten salt with a relatively high temperature at the top of the tank body 1 and gradually heats up, reducing the temperature difference between the fluid and the molten salt in the heat exchange pipe at the same height position, reducing the risk of vibration and abnormal sound of the heat exchange pipe, and improving the safety of the device. In other embodiments, the heat exchange pipe (the first heat exchange pipe 2 and the second heat exchange pipe 4 ) may also be serpentine and arranged in a circuitous manner up and down along the height direction of the tank body 1 or the heat transfer inner tube 3 .

[0050] refer to Figure 1 , Figure 4-Figure 7 In one embodiment, the flow cross-section of the first heat exchange pipe 2 or the flow cross-section of the second heat exchange pipe 4 is in the shape of a circular arch. It is understandable that when a fluid flows through the heat exchange pipe, the pipe wall of the heat exchange pipe will be subjected to the pressure of the fluid. By designing the flow cross-section of the heat exchange pipe (the first heat exchange pipe 2 and the second heat exchange pipe 4) to be in the shape of a circular arch, the pipe wall of the heat exchange pipe can maintain its original shape when subjected to the fluid pressure and is not easily deformed, thereby reducing the probability of deformation and leakage of the heat exchange pipe. In other embodiments, the flow cross-section of the heat exchange pipe (the first heat exchange pipe 2 and the second heat exchange pipe 4) can also be a triangle (refer to Figure 2 ) or rectangle (reference Figure 3 The flow cross section of the heat exchange pipe is designed to be an arch or a triangle, and there is more room for movement between the upper and lower adjacent heat exchange pipes, which is convenient for welding the pipe wall of the heat exchange pipe and the tank wall (or the wall of the heat transfer inner tube 3) to form the heat exchange pipe.

[0051] refer to Figure 5In one embodiment, the layout density of the first heat exchange pipe 2 gradually increases from the bottom of the tank body 1 to the top of the tank body 1 along the height direction of the tank body 1; and / or the layout density of the second heat exchange pipe 4 gradually increases from the bottom of the heat transfer inner cylinder 3 to the top of the heat transfer inner cylinder 3 along the height direction of the heat transfer inner cylinder 3.

[0052] It is worth noting that, combined with the temperature distribution of the molten salt heat storage material in the tank body 1 in the height direction, which is high at the top and low at the bottom, by arranging the heat exchange pipes gradually denser from bottom to top, compared with the uniform arrangement of the heat exchange pipes along the height direction, more heat from the molten salt at the high position in the tank can be absorbed, thereby improving the utilization of the heat release capacity of the molten salt, which is consistent with the distribution characteristic of the molten salt temperature, which is high at the top and low at the bottom.

[0053] In one embodiment, a second heat storage material is provided in the heat transfer inner cylinder 3. By providing the second heat storage material in the heat transfer inner cylinder 3, the heat storage and heat release capacity of the entire device is improved. It is understandable that the second heat storage material and the first heat storage material can be the same heat storage material or different types of heat storage materials. In other words, the second heat storage material can be a molten salt heat storage material or a non-molten salt heat storage material. Preferably, the second heat storage material is a non-molten salt heat storage material. By providing the non-molten salt heat storage material in the heat transfer inner cylinder 3, the non-molten salt heat storage material has a relatively low volume unit price relative to the molten salt heat storage material, which can save costs.

[0054] It should be noted that when the second heat storage material is the same as the first heat storage material, the bottom of the heat transfer inner cylinder 3 may not be closed, that is, the second heat storage material is connected to the first heat storage material. When the second heat storage material is not the same as the first heat storage material, it is preferred to seal the bottom of the heat transfer inner cylinder 3 so that the second heat storage material is not connected to the first heat storage material. If the different types of the first heat storage material and the second heat storage material do not chemically react, the bottom of the heat transfer inner cylinder 3 may not be sealed.

[0055] Specifically, non-molten salt heat storage materials have lower volume cost than molten salt heat storage materials. Non-molten salt heat storage materials are solid. Non-molten salt heat storage materials will not melt after heat storage. Compared with molten salt heat storage materials, they will not flow, and release heat slower than molten salt heat storage materials. The molten salt heat storage material mentioned in this application can be a molten salt formed by mixing 50% sodium nitrate and 50% potassium nitrate, or a molten salt formed by mixing 60% sodium nitrate and 40% potassium nitrate, or a low melting point molten salt (melting point as low as about 80°) disclosed in the patent with application number CN201911219662, or a multi-component mixed molten salt (melting point as low as 47.3°) disclosed in the patent with application number CN202311105206, or other types of molten salts. It can be understood that the molten salt heat storage material can be composed of one molten salt or a mixture of multiple molten salts. The non-molten salt heat storage material is a solid heat storage medium, which can be ceramsite, metal block, corundum block, high alumina block, dolomite block, ore, glass, gravel, sand, etc. It should be noted that the non-molten salt heat storage material can also be heat storage bricks and concrete. The non-molten salt heat storage material can also be a combination of one or more of the above example materials.

[0056] refer to Figure 7 In one embodiment, the inner tube type molten salt heat storage and heat exchange device further includes a second heating device 6, which is inserted into the second heat storage material in the heat transfer inner tube 3 in the vertical direction. By arranging the second heating device 6 in the heat transfer inner tube 3, the second heating device 6 can be used to fully heat the second heat storage material in the heat transfer inner tube 3, thereby improving the utilization of the heat storage capacity of the second heat storage material. Specifically, the first heating device 5 and the second heating device 6 can be the same type of heating device, or different types of heating devices.

[0057] In one embodiment, the first heat exchange pipe 2 and the second heat exchange pipe 4 are configured to be switchable between parallel connection and series connection.

[0058] In this embodiment, by configuring the first heat exchange pipe 2 and the second heat exchange pipe 4 to be switchable between parallel connection and series connection, the ability of the entire device to supply a fluid of a preset temperature and pressure during heat release can be improved. For example, when the entire device just starts to release heat, the first heat exchange pipe 2 and the second heat exchange pipe 4 can both independently and efficiently supply a fluid of a preset temperature and pressure. At this time, the first heat exchange pipe 2 and the second heat exchange pipe 4 are connected in parallel. As the heat release proceeds, the temperature of the heat storage material in the device gradually decreases, and one or both of the first heat exchange pipe 2 and the second heat exchange pipe 4 cannot efficiently supply a fluid of a preset temperature and pressure. At this time, the first heat exchange pipe 2 and the second heat exchange pipe 4 can be switched to a series connection. By extending the heat exchange path, it is ensured that the entire device can continue to efficiently supply a fluid of a preset temperature and pressure. Such a design improves the utilization of the heat release capacity of the heat storage material. For example, a first connecting pipe for series-parallel switching is provided between the outlet of the first heat exchange pipe 2 and the inlet of the second heat exchange pipe 4, and a switch valve is provided on the first connecting pipe. When the first heat exchange pipe 2 and the second heat exchange pipe 4 are connected in parallel, the switch valve on the first connecting pipe is closed. When the first heat exchange pipe 2 and the second heat exchange pipe 4 need to be switched in series, it is only necessary to close the valve at the front end of the inlet of the second heat exchange pipe 4 and open the switch valve on the first connecting pipe.

[0059] refer to Figure 1-Figure 4 , Figure 6 , Figure 7 In one embodiment, a plurality of heat-conducting fins 7 are provided circumferentially on the wall of the heat-transfer inner cylinder 3 .

[0060] It should be noted that by providing the heat transfer fins 7 on the heat transfer inner cylinder 3, the heat transfer fins 7 and the heat transfer inner cylinder 3 form a whole that increases the heat transfer area compared to the heat transfer inner cylinder 3 without the heat transfer fins 7, which is not only conducive to quickly transferring the heat of the heat storage material at a high position to the heat storage material at a low position, but also improves the temperature uniformity of the heat storage material in the height direction. At the same time, when the non-molten salt heat storage material is provided in the heat transfer inner cylinder 3, it is also conducive to quickly transferring the heat of the non-molten salt heat storage material to the molten salt heat storage material, thereby improving the heat conduction efficiency.

[0061] On the other hand, the present application provides a molten salt heat storage steam generation system, which adopts the aforementioned molten salt heat storage heat exchange device. The specific structure of the molten salt heat storage heat exchange device refers to the aforementioned embodiment. Since the molten salt heat storage steam generation system adopts the technical solution of the aforementioned embodiment, it at least has the beneficial effects brought by the technical solution of the aforementioned embodiment, which will not be repeated here one by one.

[0062] It should be noted that the above embodiments can be freely combined as needed. The above are only preferred implementations of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application, and these improvements and modifications should also be regarded as the protection scope of the present application.

Claims

1. An inner cylinder type molten salt heat storage and heat exchange device, characterized in that: include: A tank body, wherein a first heat exchange pipe is provided on the tank wall of the tank body; A heat transfer inner cylinder, the heat transfer inner cylinder is arranged in the tank body and coaxially with the tank body, a second heat exchange pipe is arranged on the cylinder wall of the heat transfer inner cylinder; a first heat storage material is arranged in the space between the tank body and the outside of the heat transfer inner cylinder; A first heating device is inserted into the first heat storage material outside the heat transfer inner cylinder along a vertical direction, and the first heating device is used to heat the first heat storage material.

2. The inner cylinder type molten salt heat storage and heat exchange device according to claim 1 is characterized in that: The first heat exchange pipe is arranged on the inner wall of the tank body, and the second heat exchange pipe is arranged on the outer wall of the heat transfer inner cylinder.

3. The inner cylinder type molten salt heat storage and heat exchange device according to claim 1 is characterized in that: The first heat exchange pipe is arranged in a spiral shape along the height direction of the tank body, the inlet of the first heat exchange pipe is arranged close to the bottom of the tank body, and the outlet of the first heat exchange pipe is arranged close to the top of the tank body; and / or The second heat exchange pipe is arranged in a spiral shape along the height direction of the heat transfer inner cylinder, the inlet of the second heat exchange pipe is arranged near the bottom of the heat transfer inner cylinder, and the outlet of the second heat exchange pipe is arranged near the top of the heat transfer inner cylinder.

4. The inner cylinder type molten salt heat storage and heat exchange device according to claim 3 is characterized in that: The flow cross section of the first heat exchange pipe or the flow cross section of the second heat exchange pipe is in an arch shape.

5. The inner cylinder type molten salt heat storage and heat exchange device according to claim 3 is characterized in that: The arrangement density of the first heat exchange pipe gradually increases from the bottom of the tank body to the top of the tank body along the height direction of the tank body; and / or The arrangement density of the second heat exchange pipes gradually increases from the bottom end of the heat transfer inner cylinder to the top end of the heat transfer inner cylinder along the height direction of the heat transfer inner cylinder.

6. An inner cylinder type molten salt heat storage and heat exchange device according to any one of claims 1 to 5, characterized in that: A second heat storage material is arranged in the heat transfer inner cylinder.

7. The inner cylinder type molten salt heat storage and heat exchange device according to claim 6, characterized in that: The first heat storage material is a molten salt heat storage material, and the second heat storage material is a non-molten salt heat storage material.

8. The inner cylinder type molten salt heat storage and heat exchange device according to claim 6, characterized in that: It also includes a second heating device, which is inserted into the second heat storage material in the heat transfer inner cylinder along a vertical direction.

9. An inner cylinder type molten salt heat storage and heat exchange device according to any one of claims 1-5, 7, and 8, characterized in that: The first heat exchange pipe and the second heat exchange pipe are configured to be switchable between parallel connection and series connection.

10. A molten salt heat storage steam generation system, characterized in that: A molten salt heat storage and heat exchange device according to any one of claims 1 to 9 is used.

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