Detachable preheating system of high-temperature fused salt storage tank and using method

Abstract

The invention provides a detachable preheating system of a high-temperature fused salt storage tank and a using method, and belongs to the field of energy storage devices for flexible peak regulation of photo-thermal power generation and thermal power generating units. The problems of high preheating energy consumption, low efficiency, small application range and complex installation and disassembly of heating equipment of a common preheating system in the prior art through an electric heating method are solved; a preheating gas inlet is too close to a gas outlet, so that preheating gas is exhausted too early; after preheating, a blind plate is used for sealing a preheating air inlet and a preheating air outlet, the number of open holes and welding seams is increased, and potential safety hazards are increased. The device comprises a fused salt storage tank, a preheating air inlet device and a preheating smoke exhaust device, the preheating air inlet device comprises a hot air inlet pipe, a heat insulation device and an inlet pipe tail reducing section, the preheating air inlet device and the preheating smoke exhaust device are arranged close to the top edge of the fused salt storage tank, and the distance between the preheating air inlet device and the preheating smoke exhaust device is close. The tail reducing section of the inlet pipe faces the side away from the preheating smoke exhaust device. The device is mainly used for preheating the molten salt storage tank.

Description

Technical Field

[0001] The present invention belongs to the field of energy storage devices for flexible peak regulation of solar thermal power generation and thermal power units, and in particular relates to a detachable preheating system for a high-temperature molten salt storage tank and a use method thereof. Background Art

[0002] Molten salt energy storage is one of the key core technologies of the current new power system. As an important branch of long-term energy storage, molten salt energy storage has the advantages of high energy storage density, large capacity and good stability. It can effectively solve the common discontinuity, instability and supply and demand mismatch problems of new energy such as photovoltaic thermal energy, wind power and hydropower.

[0003] The high-temperature molten salt storage tank has a large heat storage capacity, high medium temperature, large geometric dimensions of the device, and an extremely heavy metal tank body. Before the high-temperature molten salt storage tank is started, the temperature of the metal shell is close to the ambient temperature. If the high-temperature molten salt is directly filled, the molten salt will easily crystallize on the cold tank wall. In addition, after contacting the high-temperature molten salt, the metal tank body will heat up rapidly and the temperature difference between the metal tank body above and below the molten salt liquid level is large, which can easily cause damage to the equipment. Therefore, it is necessary to take appropriate methods to preheat the metal tank body of the high-temperature molten salt storage tank before the first startup to prevent accidents.

[0004] The common preheating system of high-temperature molten salt storage tanks currently has the following shortcomings: preheating high-temperature molten salt storage tanks through electric heating methods such as electric blankets has high energy consumption, low efficiency, and a small scope of application, and the installation and disassembly of the heating equipment is very complicated; the positions of the preheating air inlet and the air outlet are too close, resulting in premature discharge of the preheating gas, reducing the preheating efficiency and increasing energy consumption; the preheating air inlet and the air outlet are directly connected to the top of the high-temperature molten salt storage tank, and the related components that are only used in the preheating process cannot be removed after preheating; after preheating, the preheating air inlet and the air outlet are sealed with blind plates, which increases the use and cost of materials, while increasing the number of openings and welds on the high-temperature molten salt storage tank, increasing safety hazards. Summary of the invention

[0005] In view of this, in order to solve the problems of the common high-temperature molten salt storage tank preheating system at present, the high-temperature molten salt storage tank is preheated by electric heating methods such as electric blankets, which has high energy consumption, low efficiency, and small scope of application, and the installation and disassembly of the heating equipment is very complicated; the position of the preheating air inlet and the air outlet is too close, resulting in premature discharge of the preheating gas, reducing the preheating efficiency and increasing energy consumption; the preheating air inlet and the air outlet are directly connected to the top of the high-temperature molten salt storage tank, and the related components used only in the preheating process cannot be removed after preheating; the preheating air inlet and the air outlet are sealed with a blind plate after preheating, which increases the use and cost of materials, and at the same time increases the number of openings and welds on the high-temperature molten salt storage tank, increasing safety hazards and other problems. The present invention proposes a detachable preheating system and a method of use of a high-temperature molten salt storage tank, which is simple to install and disassemble, optimizes the setting position of the preheating air inlet and the air outlet, and improves the preheating efficiency.

[0006] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a detachable preheating system for a high-temperature molten salt storage tank and a method of use, comprising a molten salt storage tank, a preheating air intake device and a preheating smoke exhaust device, wherein the preheating air intake device is fixed to the top of the molten salt storage tank;

[0007] The top of the molten salt storage tank is provided with a smoke exhaust sleeve, and the bottom is provided with a smoke exhaust pipe guide device, and the preheating smoke exhaust device is interlaced and fixed with the molten salt storage tank through the smoke exhaust sleeve and the smoke exhaust pipe guide device;

[0008] The preheating air intake device comprises a hot gas inlet pipe, a heat insulation device and a reducing section at the tail of the inlet pipe, wherein the hot gas inlet pipe is fixedly connected to the reducing section at the tail of the inlet pipe, and the heat insulation device is fixedly connected to the top of the molten salt storage tank and is fixedly connected to the hot gas inlet pipe;

[0009] The preheating smoke exhaust device comprises a smoke exhaust pipe, a mounting guide device and a lifting ear. The top of the smoke exhaust pipe is fixedly connected to the lifting ear, and a plurality of vents are arranged on the bottom side wall. The mounting guide device is fixedly connected to the smoke exhaust sleeve. The smoke exhaust pipe passes through the smoke exhaust sleeve after being guided by the mounting guide device.

[0010] The preheating air intake device and the preheating smoke exhaust device are both arranged near the top edge of the molten salt storage tank, and the preheating air intake device and the preheating smoke exhaust device are close to each other. The reducing section at the tail of the inlet pipe faces away from the preheating smoke exhaust device to prevent the preheating gas from being directly blown into the preheating smoke exhaust device and discharged.

[0011] Furthermore, the smoke exhaust pipe guide device includes a pre-welded plate, a plurality of rib plates and a bottom bell-mouth sleeve, the bottom of the bottom bell-mouth sleeve is fixedly connected to the pre-welded plate, and the side wall is supported and fixed to the pre-welded plate by a plurality of rib plates.

[0012] Furthermore, the thermal insulation device includes a sleeve and an annular blind plate, the sleeve is fixed to the top of the molten salt storage tank, and the annular blind plate connects and fixes the sleeve to the hot gas inlet pipe to form an air interlayer.

[0013] Furthermore, the installation guide sealing device includes a top bell-mouth sleeve, a flange and a plurality of rib plates 2, the top bell-mouth sleeve is fixedly connected to the flange, the side wall is supported and fixed on the flange by a plurality of rib plates 2, and the flange is fixedly connected to the smoke exhaust sleeve.

[0014] Furthermore, the detachable preheating system for a high-temperature molten salt storage tank also includes a breathing valve and a flange cover. The top of the hot gas inlet pipe is a flange type. After the preheating process is completed, the hot gas inlet pipe is fixedly connected with the breathing valve and used as a breathing hole of the molten salt storage tank; the flange cover is fixedly connected to the smoke exhaust sleeve and used as a manhole of the molten salt storage tank.

[0015] Furthermore, a high temperature resistant gasket is provided between the flange and the smoke exhaust sleeve for sealing.

[0016] Furthermore, the plurality of ventilation holes are located at different heights, divided into 4 layers with 8 holes in total, and evenly distributed in 4 directions.

[0017] A method for using a detachable preheating system for a high-temperature molten salt storage tank comprises the following steps:

[0018] S1. Connect the hot gas inlet pipe to the pipeline of the external natural gas preheating device;

[0019] S2, start the external natural gas preheating device to continuously introduce preheated gas into the molten salt storage tank;

[0020] S3, after preheating for a period of time, the preheating gas with increased temperature is introduced to continue preheating;

[0021] S4, repeat step S3 until the temperature of the molten salt storage tank reaches the standard, and turn off the external natural gas preheating device;

[0022] S5. Disassemble the hot gas inlet pipe and the pipeline of the external natural gas preheating device;

[0023] S6. Use a breathing valve to seal and fix the hot gas inlet pipe as a breathing hole for the molten salt storage tank;

[0024] S7. Use mechanical equipment to lift and remove the exhaust pipe through the lifting lugs;

[0025] S8, dismantle and install the guide sealing device;

[0026] S9. Seal and fix the smoke exhaust sleeve with a flange cover to serve as the manhole of the molten salt storage tank.

[0027] Compared with the prior art, the detachable preheating system for a high-temperature molten salt storage tank and the use method of the present invention have the following beneficial effects:

[0028] 1. The present invention specifically designs the positions of the preheating air intake device and the preheating smoke exhaust device, thereby preventing the preheating gas from being discharged directly or without sufficient heat exchange, thereby improving the preheating efficiency and reducing energy consumption.

[0029] 2. The present invention is provided with structures such as lifting ears, installation guide devices and smoke exhaust pipe guide devices, and the preheating components can be flexibly disassembled and assembled.

[0030] 3. A pre-welded plate is provided at the bottom of the molten salt storage tank of the present invention to reduce the impact and friction loss on the tank bottom during the installation of the smoke exhaust pipe.

[0031] 4. The preheating air intake device of the present invention is provided with a heat insulation device to prevent the top of the molten salt storage tank from directly contacting the high-temperature hot air inlet pipe in the initial stage of preheating, which may cause damage due to excessive temperature difference stress.

[0032] 5. The preheating air intake device of the present invention can also be used as a breathing hole, and the smoke exhaust sleeve can also be used as a manhole, which reduces the number of openings in the storage tank and reduces safety hazards. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0034] Figure 1 The general schematic diagram of the overall structure of the preheating system of the present invention is shown;

[0035] Figure 2 A schematic diagram of the flow direction of preheating gas in the preheating system of the present invention;

[0036] Figure 3 It is a schematic diagram of the main mechanism of the preheating smoke exhaust device of the preheating system of the present invention;

[0037] Figure 4 Preheating system for the present invention Figure 3 A partial enlarged view of the middle part;

[0038] Figure 5 Preheating system for the present invention Figure 3 A partial enlarged view of point B in the middle;

[0039] Figure 6 A schematic diagram of the main mechanism of the preheating air intake device of the preheating system of the present invention;

[0040] Figure 7 Preheating system for the present invention Figure 6 A partial enlarged view of point C in the middle;

[0041] Figure 8 It is a schematic diagram of the structure of the smoke exhaust pipe guide device of the preheating system of the present invention;

[0042] Fig. 9 It is a schematic diagram of the structure of the heat insulation device of the preheating system of the present invention;

[0043] Fig.10 It is a schematic diagram of the structure of the installation guide device of the preheating system of the present invention;

[0044] Fig.11 This is a schematic diagram of the change of the preheating gas temperature and the tank body temperature over time during the preheating process of the preheating system of the present invention;

[0045] In the figure: 1-molten salt storage tank; 2-preheating air intake device; 3-preheating smoke exhaust device;

[0046] 11-smoke exhaust sleeve; 12-smoke exhaust pipe guide device; 21-hot gas inlet pipe; 22-insulation device; 23-reducing section at the tail of the inlet pipe; 31-smoke exhaust pipe; 32-installation guide device; 33-lifting ear;

[0047] 121-pre-welded plate; 122-rib plate one; 123-bottom bell-mouthed sleeve; 211-sleeve; 222-annular blind plate; 223-air interlayer; 321-top bell-mouthed sleeve; 322-flange; 323-rib plate two; 324-high temperature resistant gasket. DETAILED DESCRIPTION

[0048] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely explain the technical solutions in the embodiments of the present invention. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict, and the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0049] 1. Specific implementation method 1, see Figure 1-10 To illustrate this embodiment, a detachable preheating system for a high-temperature molten salt storage tank comprises a molten salt storage tank 1, a preheating air intake device 2 and a preheating smoke exhaust device 3, wherein the preheating air intake device 2 is fixed to the top of the molten salt storage tank 1;

[0050] The molten salt storage tank 1 is provided with a smoke exhaust sleeve 11 on the top and a smoke exhaust pipe guide device 12 on the bottom. The preheating smoke exhaust device 3 is interlaced and fixed with the molten salt storage tank 1 through the smoke exhaust sleeve 11 and the smoke exhaust pipe guide device 12; the smoke exhaust pipe guide device 12 improves the installation convenience and facilitates installation.

[0051] The preheating air intake device 2 includes a hot gas inlet pipe 21, a heat insulation device 22 and a reducing section 23 at the tail of the inlet pipe. The hot gas inlet pipe 21 is fixedly connected to the reducing section 23 at the tail of the inlet pipe. The heat insulation device 22 is fixed to the top of the molten salt storage tank 1 and is fixedly connected to the hot gas inlet pipe 21. The present invention utilizes the heat insulation device to isolate the hot gas inlet pipe 21 from the top of the molten salt storage tank 1, so as to prevent the cold top of the molten salt storage tank in the initial stage of preheating from directly contacting the high-temperature hot gas inlet pipe, and preventing failure caused by excessive temperature difference stress.

[0052] The preheating smoke exhaust device 3 includes a smoke exhaust pipe 31, an installation guide device 32 and a lifting ear 33. The top of the smoke exhaust pipe 31 is fixedly connected to the lifting ear 33, and a plurality of ventilation holes 311 are provided on the bottom side wall. The installation guide device 32 is fixedly connected to the smoke exhaust sleeve 11. The smoke exhaust pipe 31 passes through the smoke exhaust sleeve 11 after being guided by the installation guide device 32. The installation guide device 32 greatly facilitates installation and can protect the flange sealing surface of the smoke exhaust sleeve 11.

[0053] The preheating air intake device 2 and the preheating smoke exhaust device 3 are both arranged near the top edge of the molten salt storage tank 1, and the preheating air intake device 2 and the preheating smoke exhaust device 3 are close to each other, and the reducing section 23 at the tail of the inlet pipe faces the side away from the preheating smoke exhaust device 3 to prevent the preheating gas from being directly blown into the preheating smoke exhaust device 3 and discharged. The present invention optimizes the setting position of the preheating air intake device 2 and the preheating smoke exhaust device 3, so that the preheating gas flows along the circumference of the side wall in the molten salt storage tank 1, making full use of the heat of the preheating gas. According to the principle of thermal expansion and contraction, the industry generally believes that the preheating gas has a low density and will all gather at the top of the tank after entering the storage tank, gradually filling the storage tank from top to bottom, and discharging the cold air originally in the tank. Therefore, it is only necessary to set the air inlet at the top of the tank and the exhaust port at the bottom of the tank, without considering the influence of the two in the horizontal direction. Therefore, there is a layout method in which the air inlet and the exhaust port are symmetrically arranged on both sides of the tank top.

[0054] However, in actual operation, since the diameter of the molten salt storage tank is very large, usually about 30 meters, and some can reach more than 40 meters, there will be uneven distribution of cold and hot air during preheating. In addition, the density difference between the cold and hot air is not large, and the obvious stratification effect of preheated gas at the top of the tank and cold air at the bottom cannot be achieved. In addition, the preheated gas flows at a fast speed when entering the storage tank. The above-mentioned symmetrical layout method can easily lead to the preheated gas being discharged before sufficient heat exchange, especially in the part close to the tank wall.

[0055] Refer to the attached Figure 2 It can be seen that the layout of the present invention can make the preheated gas flow along the tank wall for nearly a circle before reaching the position near the outlet. After sufficient flow and heat exchange with the side wall, it is mixed with the cold air in the tank. The heat exchange process is more stable and the preheating effect on the side wall is better.

[0056] The smoke exhaust pipe guide device 12 of the present application includes a pre-welded plate 121, a plurality of rib plates 122 and a bottom bell-mouth sleeve 123. The bottom of the bottom bell-mouth sleeve 123 is fixedly connected to the pre-welded plate 121, and the side wall is supported and fixed on the pre-welded plate 121 by a plurality of rib plates 122. The bell-mouth structure is conducive to installation guidance and is convenient for rapid and accurate positioning during installation. The addition of rib plates improves the rigidity and impact resistance of the structure.

[0057] The heat insulation device 22 described in the present application includes a sleeve 221 and an annular blind plate 222. The sleeve 221 is fixed to the top of the molten salt storage tank 1. The annular blind plate 222 connects the sleeve 221 and the hot gas inlet pipe 21 to form an air interlayer 223. The air interlayer 223 has a simple structure, and the thermal conductivity of air is small, which can significantly reduce heat conduction. The air will not undergo physical or chemical changes over time, and its heat insulation performance remains effective for a long time.

[0058] The installation guide sealing device 32 of the present application comprises a top bell-mouth sleeve 321, a flange 322 and a plurality of rib plates 323. The top bell-mouth sleeve 321 is fixedly connected to the flange 322, the side wall is supported and fixed on the flange 322 by a plurality of rib plates 323, and the flange 322 is fixedly connected to the smoke exhaust sleeve 11. The bell-mouth structure is conducive to installation guidance and is convenient for quick and accurate positioning during installation.

[0059] A detachable preheating system for a high-temperature molten salt storage tank described in the present application also includes a breathing valve and a flange cover. The top of the hot gas inlet pipe 21 is a flange type. After the preheating process is completed, the hot gas inlet pipe 21 is fixedly connected with the breathing valve and used as a breathing hole for the molten salt storage tank 1; the flange cover is fixedly connected to the smoke exhaust sleeve 11 and used as a manhole for the molten salt storage tank 1. The present invention is easy to disassemble and assemble, so one hole can be used for multiple purposes, the number of tank top openings is reduced, and safety hazards are reduced.

[0060] A high temperature resistant gasket 324 is also provided between the flange 322 and the exhaust sleeve 11 for sealing. The high temperature resistant gasket 324 seals the exhaust sleeve 11 on the top of the molten salt storage tank to prevent the preheated gas from leaving the tank prematurely between the exhaust sleeve 11 and the exhaust pipe 31. The uniform arrangement ensures that the gas enters from four directions.

[0061] The multiple vent holes 311 described in the present application are located at different heights, with a total of 8 holes in 4 layers, and are evenly distributed in 4 directions. The even arrangement ensures that the gas enters the smoke exhaust pipe 31 from four directions, avoiding uneven airflow or the formation of a local low-pressure area caused by a single-direction through hole, which is conducive to the stable heat exchange process in the tank.

[0062] A method for using a detachable preheating system for a high-temperature molten salt storage tank comprises the following steps:

[0063] S1, connecting the hot gas inlet pipe 21 to the pipeline of the external natural gas preheating device;

[0064] S2, start the external natural gas preheating device to continuously introduce preheated gas into the molten salt storage tank 1;

[0065] S3, after preheating for a period of time, the preheating gas with increased temperature is introduced to continue preheating;

[0066] S4, repeat step S3 until the temperature of the molten salt storage tank 1 reaches the standard, and turn off the external natural gas preheating device;

[0067] S5, dismantling the hot gas inlet pipe 21 and the pipeline of the external natural gas preheating device;

[0068] S6. Use a breathing valve to seal and fix the hot gas inlet pipe 21 as a breathing hole for the molten salt storage tank 1;

[0069] S7, using mechanical equipment to lift and remove the smoke exhaust pipe 31 through the lifting lug 33;

[0070] S8, dismantling and installing the guide sealing device 32;

[0071] S9. Seal and fix the smoke exhaust sleeve 11 with a flange cover to serve as a manhole for the molten salt storage tank 1.

[0072] The method for using the preheating system of the present invention has simple steps and quick assembly and disassembly. After the preheating is completed, the system can be quickly disassembled and the opening can be sealed with components as a breathing hole and a manhole to achieve new uses.

[0073] The embodiments of the present invention disclosed above are only used to help illustrate the present invention. The embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. According to the content of this specification, many modifications and changes can be made. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well.

Claims

1. A detachable preheating system for a high-temperature molten salt storage tank, characterized in that: It comprises a molten salt storage tank (1), a preheating air intake device (2) and a preheating smoke exhaust device (3), wherein the preheating air intake device (2) is fixed to the top of the molten salt storage tank (1); The top of the molten salt storage tank (1) is provided with a smoke exhaust sleeve (11), and the bottom is provided with a smoke exhaust pipe guide device (12); the preheating smoke exhaust device (3) is interlaced and fixed with the molten salt storage tank (1) through the smoke exhaust sleeve (11) and the smoke exhaust pipe guide device (12); The preheating air intake device (2) comprises a hot air inlet pipe (21), a heat insulating device (22) and a reducing section (23) at the tail end of the inlet pipe, the hot air inlet pipe (21) is fixedly connected to the reducing section (23) at the tail end of the inlet pipe, and the heat insulating device (22) is fixedly connected to the top of the molten salt storage tank (1) and the hot air inlet pipe (21); The preheating smoke exhaust device (3) comprises a smoke exhaust pipe (31), a mounting guide device (32) and a lifting ear (33); the top of the smoke exhaust pipe (31) is fixedly connected to the lifting ear (33); a plurality of vent holes (311) are provided on the bottom side wall; the mounting guide device (32) is fixedly connected to the smoke exhaust sleeve (11); the smoke exhaust pipe (31) passes through the smoke exhaust sleeve (11) after being guided by the mounting guide device (32); The preheating air intake device (2) and the preheating smoke exhaust device (3) are both arranged near the top edge of the molten salt storage tank (1), and the preheating air intake device (2) and the preheating smoke exhaust device (3) are close to each other, and the reducing section (23) at the tail end of the inlet pipe faces away from the preheating smoke exhaust device (3), so as to prevent the preheating gas from being directly blown into the preheating smoke exhaust device (3) and discharged.

2. A detachable preheating system for a high-temperature molten salt storage tank according to claim 1, characterized in that: The smoke exhaust pipe guide device (12) comprises a pre-welded plate (121), a plurality of rib plates (122) and a bottom bell-mouth sleeve (123); the bottom of the bottom bell-mouth sleeve (123) is fixedly connected to the pre-welded plate (121), and the side wall is supported and fixed on the pre-welded plate (121) by the plurality of rib plates (122).

3. A detachable preheating system for a high-temperature molten salt storage tank according to claim 2, characterized in that: The heat insulation device (22) comprises a sleeve (221) and an annular blind plate (222), wherein the sleeve (221) is fixed to the top of the molten salt storage tank (1), and the annular blind plate (222) connects and fixes the sleeve (221) and the hot gas inlet pipe (21) to form an air interlayer (223).

4. A detachable preheating system for a high-temperature molten salt storage tank according to claim 3, characterized in that: The installation guide sealing device (32) comprises a top bell-mouth sleeve (321), a flange (322) and a plurality of rib plates (323); the top bell-mouth sleeve (321) is fixedly connected to the flange (322); the side wall is supported and fixed to the flange (322) by the plurality of rib plates (323); and the flange (322) is fixedly connected to the smoke exhaust sleeve (11).

5. A detachable preheating system for a high-temperature molten salt storage tank according to claim 4, characterized in that: The detachable preheating system for a high-temperature molten salt storage tank further comprises a breathing valve and a flange cover. The top end of the hot gas inlet pipe (21) is a flange type. After the preheating process is completed, the hot gas inlet pipe (21) is fixedly connected with the breathing valve and used as a breathing hole of the molten salt storage tank (1); the flange cover is fixedly connected with the smoke exhaust sleeve (11) and used as a manhole of the molten salt storage tank (1).

6. A detachable preheating system for a high-temperature molten salt storage tank according to claim 4, characterized in that: A high temperature resistant gasket (324) is also provided between the flange (322) and the smoke exhaust sleeve (11) for sealing.

7. A detachable preheating system for a high-temperature molten salt storage tank according to claim 1, characterized in that: The multiple ventilation holes (311) are located at different heights, divided into four layers with eight holes in total, and evenly distributed in four directions.

8. A method for using the detachable preheating system for a high-temperature molten salt storage tank according to claim 5, characterized in that: Use the following steps: S1, connecting the hot gas inlet pipe (21) to the pipeline of the external natural gas preheating device; S2, starting the external natural gas preheating device to continuously introduce preheated gas into the molten salt storage tank (1); S3, after preheating for a period of time, the preheating gas with increased temperature is introduced to continue preheating; S4, repeat step S3 until the temperature of the molten salt storage tank (1) reaches the standard, and turn off the external natural gas preheating device; S5, dismantling the hot gas inlet pipe (21) and the pipeline of the external natural gas preheating device; S6. Use a breathing valve to seal and fix the hot gas inlet pipe (21) to serve as a breathing hole for the molten salt storage tank (1); S7, using mechanical equipment to lift and remove the smoke exhaust pipe (31) through the lifting lug (33); S8, dismantling and installing the guide sealing device (32); S9. Use a flange cover to seal and fix the smoke exhaust sleeve (11) to serve as a manhole for the molten salt storage tank (1).

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