Fused salt electric heater system

Abstract

The embodiment of the invention provides a fused salt electric heater system which comprises a heater shell, an electric heating pipe and a pipe sleeve, the heater shell is provided with an inlet and an outlet, the inlet and the outlet are formed in the two ends of the heater shell respectively, the electric heating pipe is arranged in the heater shell, the sleeve is arranged in the heater shell, the electric heating pipe is sleeved with the sleeve, and the electric heating pipe is sleeved with the sleeve. And a fused salt flowing channel is formed between the sleeve and the electric heating pipe and is communicated with the inlet and the outlet respectively. By arranging the pipe sleeve on the outer side of the electric heating pipe in a sleeving manner, the fused salt only flows in the fused salt flowing channel between the electric heating pipe and the pipe sleeve, so that the flowing speed of the fused salt in the fused salt flowing channel is increased, namely, the flowing speed of the fused salt on the surface of the electric heating pipe is increased, and heat on the surface of the electric heating pipe is quickly taken away; the temperature of the surface of the electric heating pipe is prevented from exceeding the upper limit, and the molten salt is prevented from being decomposed, so that the heat storage performance of the molten salt is ensured, and meanwhile, the corrosion to each part of the electric heater and the pollution to the environment caused by the decomposition of the molten salt are reduced.

Description

Technical Field

[0001] The embodiments of the present disclosure belong to the technical field of electric heating equipment, and specifically relate to a molten salt electric heater system. Background Art

[0002] In existing shell and tube molten salt electric heaters, the temperature of the electric heater tube wall may exceed the upper limit of the molten salt operating temperature due to untimely heat transfer, resulting in molten salt decomposition. A small amount of molten salt decomposition is not easy to detect, causing the electric heating tube to operate at an overtemperature for a long time. Molten salt decomposition not only affects its heat storage performance, but also the chemical substances produced by molten salt decomposition, such as nitrite and oxygen, will corrode the materials of the electric heater and shorten the service life of the electric heating equipment. In addition, NO generated by molten salt decomposition x It will also cause pollution to the environment. Summary of the invention

[0003] The embodiments of the present disclosure aim to solve at least one of the technical problems existing in the prior art and provide a molten salt electric heater system.

[0004] An embodiment of the present disclosure provides a molten salt electric heater system, the molten salt electric heater system comprising:

[0005] A heater housing, wherein the heater housing has an inlet and an outlet, wherein the inlet and the outlet are respectively arranged at two ends of the heater housing;

[0006] An electric heating tube, the electric heating tube is arranged in the heater housing;

[0007] The sleeve is arranged in the heater housing, the sleeve is sleeved on the electric heating tube, a molten salt flow channel is formed between the sleeve and the electric heating tube, and the molten salt flow channel is connected with the inlet and the outlet respectively.

[0008] In some embodiments of the present disclosure, a plurality of sharp portions are provided on the outer wall of the electric heating tube, and the plurality of sharp portions are located in the molten salt flow channel.

[0009] In some embodiments of the present disclosure, the plurality of sharp portions are evenly and spaced apart along the length direction of the electric heating tube.

[0010] In some embodiments of the present disclosure, the plurality of sharp portions are evenly and spaced apart along the circumference of the electric heating tube.

[0011] In some embodiments of the present disclosure, the sharp portion is convex from the outer wall of the electric heating tube toward the inner wall of the sleeve, and the sharp portion is convex in the opposite direction of the flow of the molten salt.

[0012] In some embodiments of the present disclosure, the electric heating tube includes two non-heating tube segments and a heating tube segment, the two non-heating tube segments are connected to both ends of the heating tube segment, the sleeve is sleeved on the heating tube segment, the molten salt flow channel is formed between the sleeve and the heating tube segment, and a plurality of sharp portions are arranged on the outer wall of the heating tube segment.

[0013] In some embodiments of the present disclosure, the heating pipe segment includes a first pipe segment and a second pipe segment. The first pipe segment and the second pipe segment are arranged in sequence along the flow direction of the molten salt, and the surface heat load of the first pipe segment is less than the surface heat load of the second pipe segment.

[0014] In some embodiments of the present disclosure, the length of the second pipe segment is smaller than the length of the first pipe segment.

[0015] In some embodiments of the present disclosure, the heater housing includes: an inlet space, a heating space and an outlet space. The inlet space, the heating space and the outlet space are arranged in sequence along the flow direction of the molten salt. The inlet space is connected to the inlet, and the outlet space is connected to the outlet. The two non-heating pipe sections are respectively arranged in the inlet space and the outlet space, the heating pipe section and the sleeve are both arranged in the heating space, and the molten salt flow channel connects the inlet space and the outlet space.

[0016] In some embodiments of the present disclosure, two ends of the heater housing are respectively provided with an inlet pipe and an outlet pipe, the inlet pipe is connected with the inlet, the outlet pipe is connected with the outlet, and an online analyzer is provided on the outlet pipe.

[0017] In the molten salt electric heater system of the embodiment of the present disclosure, an electric heating tube and a tube sleeve are arranged in the heater shell, wherein the tube sleeve is arranged on the electric heating tube, and a molten salt flow channel is formed between the tube sleeve and the electric heating tube, and the two ends of the molten salt flow channel are respectively connected to the inlet and outlet of the heater shell, and the molten salt enters the molten salt flow channel between the tube sleeve and the electric heating tube from the inlet of the heater shell, flows through the molten salt flow channel, and finally the molten salt is discharged from the heater shell through the outlet. By arranging the tube sleeve on the outer side of the electric heating tube, the molten salt flows only in the molten salt flow channel between the electric heating tube and the tube sleeve. Since the molten salt flow channel becomes smaller, the flow speed of the molten salt in the molten salt flow channel is increased, that is, the flow speed of the molten salt on the surface of the electric heating tube is increased, so as to quickly take away the heat on the surface of the electric heating tube, prevent the temperature on the surface of the electric heating tube from exceeding the upper limit, and avoid the decomposition of the molten salt, thereby ensuring the heat storage performance of the molten salt, and at the same time, reducing the corrosion of the chemical substances produced by the decomposition of the molten salt to various parts of the electric heater, ensuring the service life of the electric heating equipment, and reducing the NO produced by the decomposition of the molten salt. x It will also cause pollution to the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of a molten salt electric heater system according to an embodiment of the present disclosure;

[0019] Figure 2 for Figure 1 A magnified view of part A;

[0020] Figure 3 for Figure 1 A magnified view of part B;

[0021] Figure 4 for Figure 1 Enlarged view of part C.

[0022] The reference numerals in the accompanying drawings represent the following:

[0023] 100. Molten salt electric heater system;

[0024] 10. Heater housing; 11. Inlet pipe; 12. Outlet pipe; 101. Inlet space; 102. Heating space; 103. Outlet space; 104. Molten salt flow channel;

[0025] 20. Electric heating tube; 21. Heating tube section; 211. First tube section; 212. Second tube section; 22. Non-heating tube section; 23. Sharp portion;

[0026] 30. Casing;

[0027] 40. Online analyzer. DETAILED DESCRIPTION

[0028] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0029] It should be understood that the terms used herein are only for the purpose of describing specific example embodiments and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "one", "an" and "said" as used herein may also be meant to include plural forms. The terms "include", "comprise", "contain", and "have" are inclusive, and therefore specify the existence of stated features, steps, operations, elements and / or parts, but do not exclude the existence or addition of one or more other features, steps, operations, elements, parts, and / or combinations thereof. The method steps, processes, and operations described herein are not interpreted as necessarily requiring them to be performed in the specific order described or illustrated, unless the execution order is clearly indicated. It should also be understood that additional or alternative steps may be used.

[0030] Although the terms first, second, third, etc. can be used in the text to describe multiple elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms can only be used to distinguish an element, component, region, layer or section from another region, layer or section. Unless the context clearly indicates, terms such as "first", "second" and other numerical terms do not imply order or sequence when used in the text. Therefore, the first element, component, region, layer or section discussed below can be referred to as the second element, component, region, layer or section without departing from the teaching of the example embodiments.

[0031] For ease of description, spatial relative terms may be used herein to describe the relationship of one element or feature relative to another element or feature as shown in the figure, such as "inside", "outside", "inner side", "outer side", "below", "below", "above", "above", etc. Such spatial relative terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the figure. For example, if the device in the figure is turned over, then the elements described as "below other elements or features" or "below other elements or features" will subsequently be oriented as "above other elements or features" or "above other elements or features". Therefore, the example term "below..." can include both upper and lower orientations. The device can be oriented otherwise (rotated 90 degrees or in other directions) and the spatial relative descriptors used in the text are interpreted accordingly.

[0032] like Figure 1As shown, an embodiment of the present disclosure provides a molten salt electric heater system 100, which includes: a heater shell 10, an electric heating tube 20 and a sleeve 30. Specifically, the heater shell 10 has an inlet (not shown in the figure) and an outlet (not shown in the figure), the inlet and the outlet are respectively arranged at both ends of the heater shell 10, the electric heating tube 20 is arranged in the heater shell 10, the sleeve 30 is arranged in the heater shell 10, the sleeve 30 is sleeved on the electric heating tube 20, and a molten salt flow channel 104 is formed between the sleeve 30 and the electric heating tube 20, and the molten salt flow channel 104 is connected to the inlet and the outlet respectively.

[0033] In the molten salt electric heater system 100 of the embodiment of the present disclosure, an electric heating tube 20 and a tube sleeve are arranged in the heater shell 10, wherein the tube sleeve is sleeved on the electric heating tube 20, and a molten salt flow channel 104 is formed between the tube sleeve and the electric heating tube 20, and both ends of the molten salt flow channel 104 are respectively connected to the inlet and outlet of the heater shell 10, and the molten salt enters the molten salt flow channel 104 between the tube sleeve and the electric heating tube 20 from the inlet of the heater shell 10, flows through the molten salt flow channel 104, and finally the molten salt is discharged from the heater shell 10 through the outlet. By arranging a pipe sleeve on the outer side of the electric heating tube 20, the molten salt flows only in the molten salt flow channel 104 between the electric heating tube 20 and the pipe sleeve. As the molten salt flow channel 104 becomes smaller, the flow speed of the molten salt in the molten salt flow channel 104 is increased, that is, the flow speed of the molten salt on the surface of the electric heating tube 20 is increased, so as to quickly take away the heat on the surface of the electric heating tube 20, prevent the temperature on the surface of the electric heating tube 20 from exceeding the upper limit, and avoid the decomposition of the molten salt, thereby ensuring the heat storage performance of the molten salt. At the same time, the corrosion of the chemical substances produced by the decomposition of the molten salt to various parts of the electric heater is reduced, the service life of the electric heating equipment is guaranteed, and the NO generated by the decomposition of the molten salt is reduced. X It will also cause pollution to the environment.

[0034] In some embodiments of the present disclosure, the heater housing 10 includes: an inlet space 101, a heating space 102, and an outlet space 103. The inlet space 101, the heating space 102, and the outlet space 103 are sequentially arranged along the flow direction of the molten salt, and the heating space 102 is not connected to the inlet space 101 and the outlet space 103 at both ends thereof. The inlet space 101 is connected to the inlet, and the molten salt enters the inlet space 101 from the inlet. The outlet space 103 is connected to the outlet, and the molten salt in the outlet space 103 is discharged from the heater housing 10 through the outlet. The molten salt in the inlet space 101 will not directly enter the outlet space 103 through the heating space 102.

[0035] Specifically, the electric heating tube 20 is arranged in the inlet space 101, the heating space 102 and the outlet space 103, that is, along the length direction of the electric heating tube 20, the inlet space 101, the heating space 102 and the outlet space 103 are sequentially sleeved on the electric heating tube 20, that is, the electric heating tube 20 runs through the inlet space 101, the heating space 102 and the outlet space 103. Further, the sleeve 30 is sleeved on the electric heating tube 20, the heating space 102 is sleeved on the sleeve 30, and the sleeve 30 is only arranged in the heating space 102, and a molten salt flow channel 104 is formed between the sleeve 30 and the electric heating tube 20, that is, the sleeve 30 isolates a flow channel in the heating space 102, and the molten salt flow channel 104 is not connected with the heating space 102, so as to ensure that the molten salt flows only in the molten salt flow channel 104, so as to achieve the purpose of increasing the flow rate of the molten salt. Both ends of the molten salt flow channel 104 are connected to the inlet space 101 and the outlet space 103 respectively. The molten salt enters the molten salt flow channel 104 from the inlet space 101, flows through the molten salt flow space, and finally flows into the outlet space 103 from the molten salt flow channel 104, and is discharged from the heater housing 10 through the outlet space 103.

[0036] In some embodiments of the present disclosure, the two ends of the heater housing 10 are respectively provided with an inlet pipe 11 and an outlet pipe 12, the inlet pipe 11 is connected to the inlet, and the outlet pipe 12 is connected to the outlet. Specifically, the inlet pipe 11 transports the molten salt to the inlet of the heater housing 10, enters the inlet space 101 of the heater housing 10 through the inlet, and then enters the molten salt flow through, enters the outlet space 103 through the molten salt flow channel 104, and the molten salt enters the outlet pipe 12 from the outlet space 103 through the outlet. Among them, the heater housing 10 is a vertical structure, the inlet pipe 11 is provided at the bottom of the heater housing 10, and the outlet pipe 12 is provided at the top of the heater housing 10. The molten salt enters the heater housing 10 from the inlet pipe 11 at the bottom of the heater housing 10, and is discharged from the outlet pipe 12 at the top of the heater housing 10. Through simulation and experimental research, when the molten salt electric heater is arranged vertically, due to the gravity factor, the molten salt will be forced to flow downward, it is not easy to form a flow dead zone, and the local high temperature phenomenon is alleviated.

[0037] Furthermore, the molten salt electric heater system 100 also includes an online analyzer 40, which is arranged on the outlet pipe 12. The online analyzer 40 analyzes the composition of the molten salt discharged from the outlet pipe 12 in real time to obtain whether the molten salt has decomposed. When the molten salt is decomposed according to the composition of the molten salt, the flow rate of the molten salt in the inlet pipe 11 can be adjusted to increase the flow rate of the molten salt on the surface of the electric heating tube 20 and reduce the overheating of the electric heating tube 20; the heating power of the electric heating tube 20 can also be adjusted, such as increasing the surface heat load of the electric heating tube 20 to reduce the surface temperature of the electric heating tube 20. Specifically, the online analyzer 40 is an online NO XAnalyzer, by NO X Analyze and determine whether molten salt decomposition occurs. X The analyzer detected NO in the outlet pipe 12. X , it indicates that the molten salt has decomposed. At this time, the flow rate of the molten salt or the heating power on the surface of the electric heating tube 20 needs to be adjusted.

[0038] In some embodiments of the present disclosure, the electric heating tube 20 includes two non-heating tube segments 22 and a heating tube segment 21, and the two non-heating tube segments 22 are connected at both ends of the heating tube segment 21, wherein one non-heating tube segment 22 is located in the inlet space 101, and the other non-heating tube segment 22 is located in the outlet space 103, the heating tube segment 21 is located in the heating space 102, the sleeve 30 is located in the heating space 102, and the sleeve 30 is sleeved on the heating tube segment 21, and a molten salt flow channel 104 is formed between the sleeve 30 and the heating tube segment 21. When the molten salt enters the inlet space 101, the molten salt contacts the non-heating pipe segment 22 in the inlet space 101, and the non-heating pipe segment 22 does not heat the molten salt. When the molten salt enters the molten salt flow channel 104 from the inlet space 101, the heating pipe segment 21 contacts the molten salt, and the heating pipe segment 21 heats the molten salt in the molten salt flow channel 104. When the molten salt enters the outlet space 103 from the molten salt flow channel 104, the molten salt contacts the non-heating pipe segment 22 in the outlet space 103, and the non-heating pipe segment 22 does not heat the molten salt.

[0039] In some embodiments of the present disclosure, the heating pipe segment 21 includes a first pipe segment 211 and a second pipe segment 212. The first pipe segment 211 and the second pipe segment 212 are arranged in sequence along the flow direction of the molten salt, that is, when the molten salt flows along the molten salt flow channel 104, it first passes through the first pipe segment 211 and then passes through the second pipe segment 212. Since the greater the surface heat load, the higher the surface temperature of the electric heating pipe 20, the over-temperature area of ​​the vertical structure molten salt electric heater system 100 is mainly in its upper part. Therefore, the surface heat load of the second pipe segment 212, which is prone to surface over-temperature, is set to be smaller, and the surface heat load of the first pipe segment 211, which is not prone to surface over-temperature, is set to be larger, that is, the surface heat load of the first pipe segment 211 is less than the surface heat load of the second pipe segment 212, so as to ensure that the second pipe segment 212, which is prone to surface over-temperature, will not be over-heated. Specifically, the surface heat load of the first pipe segment 211 is 6W / cm 2 The surface heat load of the second pipe section 212 is 2W / cm 2 Specifically, the surface heat load of the heating pipe section 21 is changed by setting the resistance value of the heating wire.

[0040] In some embodiments of the present disclosure, the length of the second pipe segment 212 is less than the length of the first pipe segment 211, that is, the length of the pipe segment with a small surface heat load is less than the length of the pipe segment with a large surface heat load. The length of the first pipe segment 211 and the length of the second pipe segment 212 are both related to the over-temperature area, wherein the length of the second pipe segment 212 covers the area prone to over-temperature, and the length of the first pipe segment 211 does not involve the area prone to over-temperature. Specifically, the length of the first pipe segment 211 is twice the length of the second pipe segment 212, that is, the first pipe segment 211 occupies two-thirds of the heating pipe segment 21, and the second pipe segment 212 occupies one-third of the heating pipe segment 21.

[0041] It should be noted that in this embodiment, the non-heating pipe segment 22 and the heating pipe segment 21 are controlled by controlling the resistance of the heating wire to control whether they are heated or the surface heat load of the heating. Similarly, the surface heat loads of the first pipe segment 211 and the second pipe segment 212 are different, which is also achieved by controlling the resistance of the resistance wire of the first pipe segment 211 and the second pipe segment 212 to be different.

[0042] like Figure 2 and Figure 3 As shown, in some embodiments of the present disclosure, a plurality of sharp portions 23 are provided on the outer wall of the electric heating tube 20, and the plurality of sharp portions 23 are located in the molten salt flow channel 104. When the molten salt flows along the electric heating tube 20 in the molten salt flow channel 104, the molten salt passes through the sharp portions 23, and the sharp portions 23 have sharp edges, which can destroy the boundary layer of the fluid molten salt, thereby increasing the turbulence of the molten salt fluid, and further improving the heat exchange efficiency between the electric heating tube 20 and the fluid molten salt, so as to avoid overheating on the surface of the electric heating tube 20.

[0043] Specifically, multiple sharp portions 23 can be set on the non-heating tube segment 22 and the heating tube segment 21 of the electric heating tube 20. However, since the non-heating tube of the electric heating tube 20 does not heat the molten salt, there is no overtemperature on the surface of the non-heating tube. Therefore, in order to simplify the processing process of the non-heating tube segment 22 and improve the overall production efficiency of the electric heating tube 20, multiple sharp portions 23 are only set on the outer wall of the heating tube segment 21.

[0044] In some embodiments of the present disclosure, a plurality of sharp portions 23 are evenly and spacedly arranged along the length direction of the electric heating tube 20. Specifically, a plurality of sharp portions 23 are evenly and spacedly arranged along the length direction of the heating tube segment 21 to ensure that the flow velocity along the length direction of the heating tube segment 21 is relatively uniform, thereby ensuring that the surface temperature of the heating tube segment 21 is relatively uniform. Further, a plurality of sharp portions 23 are evenly and spacedly arranged along the length direction of the electric heating tube 20 in the first tube segment 211 and the second tube segment 212.

[0045] In some embodiments of the present disclosure, a plurality of sharp portions 23 are evenly and spacedly arranged along the circumference of the electric heating tube 20. Specifically, a plurality of sharp portions 23 are evenly and spacedly arranged along the circumference of the heating tube segment 21 to ensure that the circumferential flow velocity of the heating tube segment 21 is relatively uniform, thereby ensuring that the surface temperature of the heating tube segment 21 is relatively uniform. Further, a plurality of sharp portions 23 are evenly and spacedly arranged along the circumference of the electric heating tube 20 in the first tube segment 211 and the second tube segment 212.

[0046] In some embodiments of the present disclosure, the sharp portion 23 is protruded from the outer wall of the heating tube segment 21 of the electric heating tube 20 toward the inner wall of the sleeve 30, and the sharp portion 23 is protruded in the opposite direction of the molten salt flow, that is, the sharp portion 23 is a protruding structure formed on the surface of the heating tube segment 21, and the protruding structure is formed by extending in the direction of the sleeve 30, and the protruding structure is formed by extending in the opposite direction of the molten salt flow, that is, the protruding structure is formed by extending obliquely downward toward the heating tube segment 21.

[0047] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present disclosure, but the present disclosure is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and substance of the present disclosure, and these modifications and improvements are also considered to be within the scope of protection of the present disclosure.

Claims

1. A molten salt electric heater system, characterized in that: The molten salt electric heater system comprises: A heater housing, wherein the heater housing has an inlet and an outlet, wherein the inlet and the outlet are respectively arranged at two ends of the heater housing; An electric heating tube, the electric heating tube is arranged in the heater housing; The sleeve is arranged in the heater housing, the sleeve is sleeved on the electric heating tube, a molten salt flow channel is formed between the sleeve and the electric heating tube, and the molten salt flow channel is connected with the inlet and the outlet respectively.

2. The molten salt electric heater system according to claim 1, characterized in that: A plurality of sharp portions are arranged on the outer wall of the electric heating tube, and the plurality of sharp portions are located in the molten salt flow channel.

3. The molten salt electric heater system according to claim 2, characterized in that: The plurality of sharp portions are evenly and spaced apart along the length direction of the electric heating tube.

4. The molten salt electric heater system according to claim 2, characterized in that: The plurality of sharp portions are evenly and spacedly arranged along the circumference of the electric heating tube.

5. The molten salt electric heater system according to claim 2, characterized in that: The sharp portion is convex from the outer wall of the electric heating tube toward the inner wall of the sleeve, and the sharp portion is convex in the reverse direction of the molten salt flow.

6. The molten salt electric heater system according to claim 2, characterized in that: The electric heating tube includes two non-heating tube sections and a heating tube section, the two non-heating tube sections are connected to the two ends of the heating tube section, the sleeve is sleeved on the heating tube section, the molten salt flow channel is formed between the sleeve and the heating tube section, and a plurality of the sharp portions are arranged on the outer wall of the heating tube section.

7. The molten salt electric heater system according to claim 6, characterized in that: The heating pipe segment includes a first pipe segment and a second pipe segment. The first pipe segment and the second pipe segment are arranged in sequence along the flow direction of the molten salt. The surface heat load of the first pipe segment is smaller than the surface heat load of the second pipe segment.

8. The molten salt electric heater system according to claim 7, characterized in that: The length of the second pipe section is shorter than the length of the first pipe section.

9. The molten salt electric heater system according to claim 6, characterized in that: The heater housing comprises: an inlet space, a heating space and an outlet space. The inlet space, the heating space and the outlet space are arranged in sequence along the flow direction of the molten salt. The inlet space is connected to the inlet, and the outlet space is connected to the outlet. The two non-heating pipe sections are respectively arranged in the inlet space and the outlet space. The heating pipe section and the sleeve are both arranged in the heating space. The molten salt flow channel connects the inlet space and the outlet space.

10. The molten salt electric heater system according to claim 1, characterized in that: The two ends of the heater housing are respectively arranged at an inlet pipe and an outlet pipe, the inlet pipe is communicated with the inlet, the outlet pipe is communicated with the outlet, and an online analyzer is arranged on the outlet pipe.

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