High-efficiency annular spiral flow channel molten salt electric heater and heating method thereof

Abstract

The application discloses a high-efficiency annular spiral flow channel molten salt electric heater and a heating method thereof, which comprises a heater shell, the inside of the heater shell is provided with a wrapping cylinder, the inside of the wrapping cylinder is provided with a center cylinder, the outer circumferential side of the center cylinder is provided with spiral baffles, the outer circumferential side of the center cylinder is further provided with alternately symmetrical support net plates between the spiral baffles, and high-efficiency electric heating pipes are arranged on the spiral baffles and the support net plates. The spiral flow channel formed by the center cylinder and the spiral baffles in the wrapping cylinder is adopted for spiral heating, the heat transfer capacity of the center position is avoided from being poor due to excessively low flow velocity, local temperature is avoided from being excessively high to form a temperature dead zone, molten salt is avoided from directly flowing out through the inner wall of the electric heater shell, the electric heater fails to have a heating effect on the part of the molten salt, the high-efficiency electric heating pipes are arranged in an annular array distribution with the center cylinder as the center, the molten salt fluid is fully heated, the heat exchange performance is stronger, and the heat exchange efficiency is improved.

Description

Technical Field

[0001] This invention belongs to the field of heater technology, specifically relating to a high-efficiency annular spiral flow channel molten salt electric heater and its heating method. Background Technology

[0002] Molten salt is a molten substance formed by melting salts. It is now widely used in the chemical and metallurgical industries. It is a type of salt that is solid at standard temperature and atmospheric pressure, but becomes liquid when the temperature rises. Molten inorganic salts are usually called molten salts, but now it also includes oxide melts and molten organic substances. According to composition, it can be divided into binary salts, ternary salts, and polybasic salts.

[0003] Compared to other more efficient energy storage technologies, electrothermal energy storage has advantages such as no geographical limitations, low material costs, and mature related technologies. As the core equipment for converting electrical energy into thermal energy storage, electric heaters have advantages such as strong scalability, mature technology, and simple structure. In addition, when combined with thermal storage systems, they can smooth the output of renewable energy, assist thermal power units in frequency regulation and peak shaving, and maintain grid frequency stability. Molten salt electric heaters have emerged to address this need. Molten salt thermal energy storage technology can solve the energy storage problem in solar thermal power generation, so molten salt electric heaters are commonly used to solve the heating problem in thermal energy storage systems.

[0004] Currently, spiral baffle molten salt electric heaters have the following disadvantages:

[0005] 1. Existing electric heaters use bare tubes for heating tube bundles. The heat transfer performance of bare tubes is weaker than that of high-efficiency heat exchange tubes, resulting in low heat exchange efficiency.

[0006] 2. The medium flow rate is relatively small at the center of the electric heater, and the surface temperature of the heat exchange tubes is not easily carried away, which quickly forms a temperature dead zone. This leads to excessively high local temperature of the electric heater, which can easily damage the equipment when the heating power is high.

[0007] 3. The medium to be heated in the electric heater is prone to flow along the cylinder wall where the resistance is lower, and the electric heater does not heat this part of the medium, resulting in poor heating effect;

[0008] 4. The electric heater lacks internal support elements to support the electric heating tube. The spiral baffle must not only support the electric heating tube, but also guide the flow and enhance heat transfer. This makes the spiral baffle difficult to manufacture and costly.

[0009] Therefore, we propose a high-efficiency annular spiral flow channel molten salt electric heater and its heating method. Summary of the Invention

[0010] The purpose of this invention is to provide a high-efficiency annular spiral flow channel molten salt electric heater and its heating method to solve the problems mentioned in the background art.

[0011] To achieve the above objectives, the present invention provides the following technical solution: a high-efficiency annular spiral flow channel molten salt electric heater, comprising a heater housing, wherein a feed port and a discharge port are respectively provided on the outer periphery of both ends of the heater housing, a wrapping cylinder is provided inside the heater housing, a central cylinder is provided inside the wrapping cylinder, a spiral baffle is provided on the outer periphery of the central cylinder, and alternating symmetrical support mesh plates located between the spiral baffles are also provided on the outer periphery of the central cylinder, and high-efficiency electric heating tubes are arranged in a ring array around the central cylinder on the spiral baffles and the support mesh plates.

[0012] Preferably, both ends of the wrapping cylinder are outwardly expanding conical structures, both ends of the wrapping cylinder are welded to the inner sidewall of the heater housing, and the two ends of the wrapping cylinder are respectively located between the feed port and the discharge port on the heater housing.

[0013] Preferably, one end of the central cylinder is disposed inside the heater housing near the feed port via a fixing plate, and the fixing plate is provided with a heating end of an electric heating tube, which is connected to the high-efficiency electric heating tube.

[0014] Preferably, the high-efficiency electric heating tube is one of the following: a corrugated electric heating tube, a segmented electric heating tube, a longitudinal ribbed groove electric heating tube, a transverse ribbed groove electric heating tube, or a spiral groove electric heating tube.

[0015] Preferably, the inner ring side of the spiral baffle is welded to the outer circumference side of the central cylinder, and the spiral baffle is provided with a first through hole for the high-efficiency electric heating tube to pass through.

[0016] Preferably, the supporting mesh plate is a semi-circular supporting mesh plate, with the inner ring side of the supporting mesh plate welded to the outer periphery of the central cylinder, and the outer ring side of the supporting mesh plate welded to the inner wall of the wrapping cylinder.

[0017] Preferably, the support mesh plate has a second through hole through which the high-efficiency electric heating tube passes.

[0018] A heating method for a high-efficiency annular spiral flow channel molten salt electric heater includes the following steps:

[0019] A: The molten salt medium to be heated is conveyed into the heater housing from the feed port and directly enters the inside of the wrapping cylinder;

[0020] B: Then the molten salt medium to be heated flows through the spiral flow channel formed by the central cylinder and the spiral baffle inside the wrapping cylinder. During this process, the high-efficiency electric heating tubes distributed in a ring array with the central cylinder as the center fully heat the molten salt medium to be heated, and obtain the heated molten salt medium.

[0021] C: The heating molten salt medium is discharged from the rear end of the wrapping cylinder through the outlet port of the heater housing, and the heating is completed.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] 1. In this invention, high-efficiency electric heating tubes such as corrugated drum-shaped electric heating tubes, corrugated electric heating tubes, longitudinal rib transverse groove electric heating tubes, transverse rib transverse groove electric heating tubes, or spiral groove electric heating tubes are used to replace traditional bare tubes. These tubes have stronger heat exchange performance and improve heat exchange efficiency. Moreover, the high-efficiency electric heating tubes can prevent and remove scale on their own and compensate for temperature stress. This saves resources while reducing manufacturing costs, the risk of damage caused by temperature stress, and the difficulty of maintenance and cleaning caused by dirt after use.

[0024] 2. This invention uses a spiral flow channel formed by the central cylinder inside the wrapping cylinder and the spiral baffle for spiral heating. Compared with the existing spiral flow channel, on the one hand, it eliminates the low flow velocity area in the center, avoiding poor heat transfer capacity and local high temperature dead zone caused by excessively low flow velocity in the center. On the other hand, it avoids the molten salt from flowing directly through the inner wall of the electric heater shell, which would prevent the electric heater from heating this part of the molten salt, thereby improving the molten salt heating effect of the electric heater.

[0025] 3. The present invention uses a wrapping tube with enlarged ends, with the two ends of the wrapping tube connected to the inner wall of the heater housing, which further enhances the flow guiding effect and avoids the molten salt fluid flowing along the inner wall of the heater housing from the edge of the baffle plate in the heating area, thus effectively enhancing the heating effect of the heater.

[0026] 4. The present invention adopts a semi-annular support mesh plate designed based on the spiral flow channel formed by the central cylinder inside the wrapping cylinder and the spiral baffle. The support mesh plate provides support for each high-efficiency electric heating tube, so that the functions of the spiral baffle and the support mesh plate are separated. The spiral baffle plays the role of guiding flow and enhancing heat transfer, while the support mesh plate plays the role of supporting the heating tube. This reduces the manufacturing difficulty of the spiral baffle and reduces the overall equipment manufacturing cost. Attached Figure Description

[0027] Figure 1 This is a partial cross-sectional structural schematic diagram of the present invention;

[0028] Figure 2 This is a three-dimensional structural diagram of the present invention;

[0029] Figure 3 This is a partial three-dimensional structural schematic diagram of the present invention;

[0030] Figure 4 This is a partial three-dimensional structural schematic diagram of the present invention;

[0031] Figure 5This is a partial three-dimensional structural schematic diagram of the present invention;

[0032] Figure 6 This is a three-dimensional structural diagram of the wrapping tube of the present invention;

[0033] Figure 7 This is a schematic diagram of the structure of the support mesh plate of the present invention;

[0034] Figure 8 This is a schematic diagram of the structure of the high-efficiency electric heating tube of the present invention.

[0035] In the diagram: 1. Heater housing; 2. Feed port; 3. Discharge port; 4. Wrapping cylinder; 5. Central cylinder; 6. Spiral baffle; 7. Support mesh plate; 8. High-efficiency electric heating tube; 9. Fixed plate; 10. Heating end of electric heating tube. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] Please see Figures 1-8The present invention provides a high-efficiency annular spiral flow channel molten salt electric heater, comprising a heater housing 1, with an inlet port 2 and an outlet port 3 respectively provided on the outer periphery of both ends of the heater housing 1. A wrapping cylinder 4 is provided inside the heater housing 1, with both ends of the wrapping cylinder 4 being outwardly expanding conical structures. Both ends of the wrapping cylinder 4 are welded to the inner wall of the heater housing 1, and the two ends of the wrapping cylinder 4 are respectively located between the inlet port 2 and the outlet port 3 on the heater housing 1. A central cylinder 5 is provided inside the wrapping cylinder 4, with one end of the central cylinder 5 located inside the heater housing 1 near the inlet port 2 via a fixing plate 9. An electric heating tube heating end 10 is provided on the fixing plate 9, and the electric heating tube heating end 10 is connected to a high-efficiency electric heating tube 8. A spiral baffle 6 is provided on the outer periphery of the central cylinder 5. The inner ring side of the tube is welded to the outer circumference of the central cylinder 5. The outer circumference of the central cylinder 5 is also provided with alternating symmetrical support mesh plates 7 located between the spiral baffles 6. The support mesh plate 7 is a semi-circular support mesh plate. The inner ring side of the support mesh plate 7 is welded to the outer circumference of the central cylinder 5, and the outer ring side of the support mesh plate 7 is welded to the inner wall of the wrapping cylinder 4. The spiral baffles 6 and the support mesh plate 7 are provided with high-efficiency electric heating tubes 8 arranged in a ring array with the central cylinder 5 as the center. The spiral baffles 6 has a first through hole for the high-efficiency electric heating tubes 8 to pass through, and the support mesh plate 7 has a second through hole for the high-efficiency electric heating tubes 8 to pass through. The high-efficiency electric heating tubes 8 are one of the following: corrugated electric heating tubes, nodular electric heating tubes, longitudinal rib transverse groove electric heating tubes, transverse rib transverse groove electric heating tubes, or spiral groove electric heating tubes.

[0038] In this invention, a high-efficiency electric heating tube 8, such as a corrugated drum-shaped electric heating tube, a corrugated electric heating tube, a longitudinal rib transverse groove electric heating tube, a transverse rib transverse groove electric heating tube, or a spiral groove electric heating tube, is used to replace the traditional bare tube. This has stronger heat exchange performance and improved heat exchange efficiency. Moreover, the high-efficiency electric heating tube 8 can independently prevent and clean scale, and self-compensate for temperature stress. This saves resources while reducing manufacturing costs, the risk of damage caused by temperature stress, and the difficulty of maintenance and cleaning caused by dirt after use.

[0039] This invention employs a spiral flow channel formed by the central cylinder 5 inside the wrapping cylinder 4 and the spiral baffle 6 for spiral heating. Compared with the existing spiral flow channel, this invention eliminates the low-velocity area in the center, avoiding poor heat transfer capacity and localized high temperature dead zones caused by excessively low flow velocity in the center. It also prevents molten salt from flowing directly through the inner wall of the electric heater shell, thus preventing the electric heater from failing to heat this part of the molten salt and thereby improving the molten salt heating effect of the electric heater.

[0040] The present invention employs a wrapping cylinder 4 with enlarged ends, the two ends of which are connected to the inner wall of the heater housing 1, to further enhance the flow guiding effect and prevent the molten salt fluid from flowing into the heating area along the inner wall of the heater housing 1 at the edge of the baffle plate, thereby effectively enhancing the heating effect of the heater.

[0041] This invention employs a semi-annular support mesh plate 7 designed based on the spiral flow channel formed by the central cylinder 5 inside the wrapping cylinder 4 and the spiral baffle 6. The support mesh plate 7 provides support for each high-efficiency electric heating tube 8, allowing the spiral baffle 6 and the support mesh plate 7 to function separately. The spiral baffle 6 plays the role of guiding flow and enhancing heat transfer, while the support mesh plate 7 plays the role of supporting the heating tube. This reduces the manufacturing difficulty of the spiral baffle 6 and lowers the overall equipment manufacturing cost.

[0042] The heating method of the high-efficiency annular spiral flow channel molten salt electric heater provided by the present invention includes the following steps:

[0043] A: The molten salt medium to be heated is conveyed into the heater housing 1 from the feed port 2 and directly enters the inside of the wrapping cylinder 4;

[0044] B: Then the molten salt medium to be heated flows through the spiral flow channel formed by the central cylinder 5 and the spiral baffle 6 inside the wrapping cylinder 4. During this process, the high-efficiency electric heating tubes 8, which are arranged in a ring array with the central cylinder 5 as the center, fully heat the molten salt medium to be heated to obtain the heated molten salt medium.

[0045] C: The heating molten salt medium is discharged from the rear end of the wrapping cylinder 4 to the discharge port 3 of the heater housing 1, and the heating is completed.

[0046] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A high-efficiency annular spiral flow channel molten salt electric heater, characterized in that, The device includes a heater housing (1), with an inlet port (2) and an outlet port (3) respectively provided on the outer periphery of both ends of the heater housing (1). A wrapping cylinder (4) is provided inside the heater housing (1), and a central cylinder (5) is provided inside the wrapping cylinder (4). A spiral baffle (6) is provided on the outer periphery of the central cylinder (5). Alternating symmetrical support mesh plates (7) are also provided on the outer periphery of the central cylinder (5) between the spiral baffles (6). High-efficiency electric heating tubes (8) are arranged in a ring array with the central cylinder (5) as the center on the spiral baffles (6) and the support mesh plates (7). Both ends of the wrapping cylinder (4) are tapered structures that expand outwards. Both ends of the wrapping cylinder (4) are welded to the inner wall of the heater housing (1), and the two ends of the wrapping cylinder (4) are respectively located between the feed port (2) and the discharge port (3) on the heater housing (1).

2. The high-efficiency annular spiral flow channel molten salt electric heater according to claim 1, characterized in that: One end of the central cylinder (5) is set inside the heater housing (1) near the feed port (2) via a fixed plate (9). The fixed plate (9) is provided with an electric heating tube heating end (10), which is connected to the high-efficiency electric heating tube (8).

3. The high-efficiency annular spiral flow channel molten salt electric heater according to claim 2, characterized in that: The high-efficiency electric heating tube (8) is one of the following: a corrugated electric heating tube, a wavy electric heating tube, a longitudinal ribbed groove electric heating tube, a transverse ribbed groove electric heating tube, or a spiral groove electric heating tube.

4. The high-efficiency annular spiral flow channel molten salt electric heater according to claim 1, characterized in that: The inner ring side of the spiral baffle (6) is welded to the outer circumference side of the central cylinder (5), and the spiral baffle (6) has a first through hole for the high-efficiency electric heating tube (8) to pass through.

5. The high-efficiency annular spiral flow channel molten salt electric heater according to claim 1, characterized in that: The supporting mesh plate (7) is a semi-circular supporting mesh plate. The inner ring side of the supporting mesh plate (7) is welded to the outer circumference side of the central cylinder (5), and the outer ring side of the supporting mesh plate (7) is welded to the inner wall of the wrapping cylinder (4).

6. The high-efficiency annular spiral flow channel molten salt electric heater according to claim 1, characterized in that: The support mesh plate (7) has a second through hole through which the high-efficiency electric heating tube (8) passes.

7. A heating method for a high-efficiency annular spiral flow channel molten salt electric heater according to any one of claims 1-6, characterized in that, Includes the following steps: A: The molten salt medium to be heated is conveyed from the feed port (2) into the heater housing (1) and directly into the inside of the wrapping cylinder (4); B: Then the molten salt medium to be heated flows through the spiral flow channel formed by the central cylinder (5) and the spiral baffle (6) inside the wrapping cylinder (4). During this process, the high-efficiency electric heating tubes (8) arranged in a ring array with the central cylinder (5) as the center fully heat the molten salt medium to be heated, and obtain the heated molten salt medium. C: The heating molten salt medium is discharged from the rear end of the wrapping cylinder (4) to the discharge port (3) of the heater housing (1), and the heating is completed.

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