Molten salt storage tank cyclone preheating device and preheating method

Abstract

The present application discloses a swirl preheating device and preheating method for a molten salt storage tank. The preheating device includes a main air inlet pipe, a distribution valve, an external air inlet pipe, an internal air inlet pipe, an outer sleeve, an inner sleeve, a central pipe, a swirl generator, an upper baffle of the nozzle and a lower baffle of the nozzle. The preheating method adopts the above-mentioned preheating device, arranges the flow channel of the swirl generator as a swirl flow channel, and does not arrange the flow channel of the swirl generator as a regulating flow channel, generates a rotating jet with a tangential velocity in the swirl flow channel, generates an irrotational jet without a tangential velocity in the regulating flow channel, and the rotating jet and the irrotational jet are mixed in the upper section of the nozzle to form a fusion swirl with a lower rotation intensity. The beneficial effects of the present application: uniform preheating, by changing the flow of the preheating gas, the preheating area can be adjusted to ensure uniform temperature; supports rapid preheating, good preheating uniformity, and due to the regulating function of the preheating area, rapid preheating will not cause uneven tank temperature.

Description

Technical Field

[0001] The present application belongs to the field of molten salt heat storage technology, and specifically relates to a molten salt storage tank cyclone preheating device and preheating method. Background Art

[0002] Wind and solar energy, as key components of clean energy, have attracted significant attention due to their abundant resources and high renewability. However, the intermittent and fluctuating nature of these energy sources, particularly their significant impact on weather, season, and geographical factors, leads to unstable power supply. This often results in large amounts of electricity being unavailable for immediate consumption and therefore abandoned, a phenomenon known as "wind and solar curtailment." To effectively address this issue, large-scale, low-cost, safe, and reliable energy storage technologies have become a research hotspot.

[0003] Currently, energy storage technologies are primarily categorized into two main categories: physical energy storage and chemical energy storage. While chemical energy storage has certain applications, its limited capacity and low full-cycle efficiency make it difficult to meet the demands for large-capacity, high-efficiency energy storage. In contrast, molten salt energy storage technology, a form of physical energy storage, has become a preferred solution for addressing the instability of wind and solar power generation due to its high storage temperature (reaching over 600°C), high energy density, excellent stability, and pollution-free nature, as well as my country's abundant molten salt resources and relatively low costs. Molten salt energy storage effectively achieves "peak shaving and valley filling" of electricity by storing heat during periods of abundant wind and sunlight or low electricity demand, and releasing that heat during peak electricity demand periods. This provides an effective solution to energy shortages and uneven distribution of electricity resources.

[0004] However, when a molten salt storage tank is first commissioned or restarted after a long shutdown, the significant temperature difference between the molten salt and the tank's ambient temperature can cause the tank to experience excessive thermal shock and thermal stress. This can lead to stress cracking or deformation, seriously shortening the tank's service life. Furthermore, after commissioning, the operating temperature of the molten salt tank, exceeding 600°C, makes in-depth structural safety inspections of the equipment very difficult. Therefore, preheating the tank is essential to mitigate the structural safety risks posed by high-temperature salt injection.

[0005] In the existing technology, the preheating of molten salt storage tanks mainly adopts the gas injection method, that is, injecting gas at the top of the tank near the wall, causing the gas to spiral down and release heat energy, thereby heating the tank wall. However, this method has obvious defects: the gas flow trajectory is difficult to maintain regularity and stability, and it is easy to turn into turbulence, resulting in uneven heating of the wall surface, affecting the preheating effect. Although the use of hot air preheating device is an attempt, its complex hot air transmission pipeline design limits the hot air flow rate, making it difficult to effectively preheat large storage tanks, and the pipeline cannot be removed after the preheating is completed, which increases the risk of failure in the operation of the energy storage system, and also increases the construction cost and maintenance cost of the power station. In addition, traditional electric heating or high-temperature steam heating methods also have problems such as high use and maintenance costs, low life, low efficiency or dangerous operation.

[0006] On the other hand, for the gas preheating technology, the method of changing the flow direction of the preheating gas through active actuators (hydraulic / pneumatic pistons, motors, etc.) is conducive to improving the preheating gas distribution and preheating performance. However, the working and preheating temperature of the molten salt storage tank is as high as 600°C or above. The active mechanisms and actuators in the equipment need to cope with this high temperature environment, resulting in low equipment reliability and high cost.

[0007] In summary, the existing molten salt storage tank preheating methods all have deficiencies to varying degrees. A new, efficient and safe molten salt storage tank preheating solution is needed to solve the above technical problems and improve the stability and economy of the energy storage system. Summary of the Invention

[0008] In view of the many deficiencies in the prior art, this application aims to propose a novel, efficient and safe molten salt storage tank cyclone preheating device and preheating method to overcome the defects in the existing molten salt storage tank preheating technology:

[0009] 1. Improve preheating uniformity: In order to address the problem that the gas flow trajectory during the preheating process of the existing gas injection method is irregular and prone to turbulence, resulting in uneven heating of the local tank wall surface, this application aims to optimize the preheater design and airflow organization method to ensure stable and uniform distribution of airflow during the preheating process, thereby achieving uniform heating of the tank wall surface and improving the preheating effect.

[0010] 2. Adapting to the preheating needs of large storage tanks: Existing hot air preheating devices are complex and require customization for each tank due to pipeline design limitations. Furthermore, their preheating performance for large storage tanks is unsatisfactory. This application aims to propose a universal preheating solution applicable to storage tanks of various sizes, particularly those requiring preheating of large molten salt storage tanks, thereby improving the flexibility and scalability of energy storage systems.

[0011] 3. Improve reliability: In response to the problems of high cost and low reliability in existing technologies that promote gas preheating through active actuation mechanisms, this application aims to simplify the preheating equipment structure by optimizing the preheater structure, eliminating complex active actuation mechanisms and moving parts, avoiding flexible materials, etc., thereby improving the operation and transportation stability of the preheating system and reducing costs.

[0012] 4. Improve versatility: This application aims to optimize the preheater structure, eliminate complex active actuating mechanisms and moving parts, and provide control over the preheater jet. This allows the application to adapt to storage tanks of different diameters by changing the preheating gas flow rate and its distribution, and further adapt to storage tanks of different heights by changing the outlet pipe length, greatly enhancing the versatility of the preheating system and enabling the use of the same preheating equipment for multiple projects.

[0013] To sum up, the purpose of this application is to provide a new type of molten salt storage tank cyclone preheating device and preheating method to solve the problems of uneven preheating, high cost, poor safety, inability to adapt to large storage tanks and complex system structure in the existing technology, thereby improving the overall performance and economy of the molten salt energy storage system and providing strong support for the widespread application of clean energy.

[0014] The purpose of this application is achieved through the following technical solutions:

[0015] A swirl preheating device for a molten salt storage tank comprises a main air inlet pipe, which is connected to a distribution valve, which is respectively connected to an outer air inlet pipe and an inner air inlet pipe, the outer air inlet pipe is connected to an outer sleeve, and the inner air inlet pipe is connected to an inner sleeve, the outer sleeve, the inner sleeve and the central pipe are coaxially nested and extend into the interior of the storage tank, an outer layer flow channel is formed between the outer sleeve and the inner sleeve, an inner layer flow channel is formed between the inner sleeve and the central pipe, a swirl generator is provided in the outer layer flow channel or the inner layer flow channel, an outward-extending nozzle upper baffle is provided at the outlet of the outer sleeve, and a nozzle lower baffle located below the nozzle upper baffle is provided on the central pipe.

[0016] Furthermore, the swirl generator includes a cylinder and spiral blades. The cylinder is fixed on the central tube or the inner sleeve, and a plurality of spiral blades are evenly arranged on the outer side of the cylinder along the circumferential direction.

[0017] Furthermore, the swirl generator is located in the inner flow channel.

[0018] Furthermore, the upper baffle of the nozzle is a trumpet-shaped structure, and the lower baffle of the nozzle is a table-shaped structure.

[0019] Furthermore, the central pipe is a central exhaust pipe, the outer sleeve, the inner sleeve and the central pipe extend into the storage tank from the center of the tank top, and the central pipe extends to the center of the tank bottom.

[0020] Furthermore, the central tube is supported on the bottom of the storage tank through the exhaust pipe, and a plurality of exhaust pipe openings located at the bottom of the tank are opened on the central tube.

[0021] Furthermore, it also includes a hot blast furnace heating system, the hot blast furnace heating system is connected to the main air inlet pipe, and the central pipe is connected to the hot blast furnace heating system.

[0022] A swirl preheating method for a molten salt storage tank adopts the above-mentioned swirl preheating device for the molten salt storage tank, wherein preheated gas enters the distribution valve through a main air inlet pipe, and the distribution valve distributes the preheated gas flow rate and then flows into the inner layer flow channel and the outer layer flow channel respectively, the flow channel where a swirl generator is arranged serves as a swirl flow channel, and the flow channel where no swirl generator is arranged serves as a regulating flow channel, the preheated gas in the swirl flow channel generates a rotating jet with a tangential velocity after passing through the swirl generator, and the preheated gas in the regulating flow channel generates an irrotational jet without a tangential velocity, the rotating jet and the irrotational jet are mixed in the upper section of the nozzle to form a fused swirl with a lower rotation intensity, and the two jet flows are distributed by the distribution valve to adjust the rotation intensity of the fused swirl.

[0023] Furthermore, the swirl intensity of the fusion swirl is defined by the swirl number S_w calculated from the cross-sectional velocity distribution at a height of 0.1 times the inner diameter of the outer casing above the connection between the nozzle upper baffle and the outer casing:

[0024] ;

[0025] in, is the outer diameter of the annular flow channel, is the inner diameter of the annular flow channel, is the average axial velocity, is the average tangential velocity, is the medium density;

[0026] When all the preheated gas completely enters the nozzle through the regulating flow channel and the preheated gas is not distributed to the swirl flow channel, the swirl number S_w=0, and the preheated gas forms an irrotational jet. When it is sprayed to the lower baffle of the nozzle, it is guided by the lower baffle of the nozzle to spray toward the large angle weld between the bottom of the tank and the tank wall, and preheats the edge of the tank bottom and the large angle weld area; when the flow rate distributed by the swirl flow channel increases to a swirl number S_w greater than or equal to 0.2 and less than 0.6, the fused jet at the nozzle is affected by the rotation, and expands circumferentially under the influence of the centrifugal effect, spraying toward the lower part of the tank wall and the large angle weld, preheating the lower area of ​​the tank wall; when the flow rate distributed by the swirl flow channel increases to a swirl number S_w greater than or equal to 0.6 and less than 0.9, the fused jet at the nozzle is affected by the rotation, the centrifugal effect is further strengthened, and the fused jet further expands circumferentially When the centrifugal effect breaks through the gas viscosity limitation, the jet is no longer stable and forms an open jet with high velocity fluctuation. At this time, the fusion jet kinetic energy dissipates rapidly and cannot be stably sprayed to the wall. The preheated gas is quickly dispersed in the central area of ​​the tank. When the flow rate distributed by the swirl flow channel is further increased to a swirl number S_w greater than or equal to 0.9, until all the preheated gas passes through the swirl flow channel to generate a rotating jet, the fusion jet at the nozzle is affected by the centrifugal effect and the Coanda effect, forming a Coanda jet flowing circumferentially along the upper baffle of the nozzle. At this time, the fusion jet is guided by the upper baffle of the nozzle and flows to the upper part of the tank wall. Near the tank wall, after the fusion jet kinetic energy dissipates, the preheated gas flows to the top of the tank under buoyancy drive, and the upper part of the tank wall and the tank top area are preheated.

[0027] Furthermore, the horizontal downward inclination angle d of the upper baffle of the nozzle is greater than 10 degrees and less than 30 degrees, the connection between the upper baffle of the nozzle and the outer sleeve is chamfered, and the radius of the chamfer is greater than 0.1 times the inner diameter of the outer sleeve; the angle between the lower baffle of the nozzle and the axial direction is between 45 degrees and k-10 degrees, where k is the angle between the line connecting the connection point between the upper part of the lower baffle of the nozzle and the center pipe and the large angle weld between the bottom and the side wall of the tank and the central axis; the outermost radius of the lower baffle of the nozzle is smaller than the outermost radius of the upper baffle of the nozzle; the lowermost height of the inner sleeve is higher than the connection between the outer sleeve and the upper baffle of the nozzle by at least 0.5 times the inner diameter of the outer sleeve; the bottom of the swirl generator is higher than the lowermost bottom of the inner sleeve by at least 0.05 times the inner diameter of the outer sleeve; the connection between the top of the lower baffle of the nozzle and the center pipe is lower than the lowest point of the upper baffle of the nozzle by at least 1 times the inner diameter of the outer sleeve.

[0028] Beneficial effects of this application:

[0029] 1. Preheating is uniform. By changing the flow of preheating gas, the preheating area can be adjusted to ensure uniform temperature.

[0030] 2. It supports fast preheating with good preheating uniformity. Due to the adjustment function of the preheating area, fast preheating will not cause uneven temperature of the tank.

[0031] 3. Good applicability. The device is set in the center of the storage tank and has an adjustable function. There is no need to reset the air inlet and outlet holes and design a preheating plan according to the size and height of the storage tank. By changing the rotation intensity and flow rate of the swirl, it can match molten salt storage tanks of different sizes.

[0032] 4. It is beneficial to the strength and safety of the storage tank. The air inlet and outlet pipes in this application use a coaxial design, and only require one opening set at the center of the tank top. This reduces the number of openings compared to traditional solutions, and the location has little damage to the overall strength, and it is also easy to set up structural reinforcement devices.

[0033] 5. High reliability: There are no movable structures or active actuators within the tank, resulting in a fully fixed structure with extremely high reliability. The distribution valves required in the system are commercially available in a large number of mature solutions, offering higher reliability than custom-designed mechanisms, ensuring the overall system reliability is extremely high.

[0034] The aforementioned main solution and its various further options may be freely combined to form multiple solutions, all of which are solutions that may be adopted and claimed for protection in this application. Furthermore, in this application, (non-conflicting options) may also be freely combined with each other and with other options. After understanding the solutions of this application, those skilled in the art will understand, based on prior art and common knowledge, that there are many possible combinations, all of which are technical solutions to be protected by this application, and these are not exhaustive here. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of the overall structure of this application.

[0036] Figure 2 It is a schematic diagram of the structure of a part of this application.

[0037] Figure 3 It is a schematic diagram of a three-dimensional cross-sectional structure of a part of this application.

[0038] Figure 4 It is a schematic diagram of the three-dimensional structure of the swirl generator of this application.

[0039] Figure 5 It is a schematic diagram of the air intake support structure of the central tube of this application.

[0040] Figure 6 This is a schematic diagram of the arrangement of the upper and lower baffles of the nozzle of this application.

[0041] In the figure: 1- main air inlet pipe; 2- distribution valve; 3- external air inlet pipe; 4- internal air inlet pipe; 5- swirl generator; 6- nozzle upper baffle; 7- nozzle lower baffle; 8- outer casing; 9- inner casing; 10- center pipe; 11- exhaust pipe support; 12- exhaust pipe opening; 13- tank top; 14- tank wall; 15- tank bottom; 16- hot air furnace heating system. DETAILED DESCRIPTION

[0042] The following non-limiting examples illustrate the present application.

[0043] Example 1

[0044] refer to Figures 1 to 6 As shown, a swirl preheating device for a molten salt storage tank includes a main air inlet pipe 1, a distribution valve 2, an external air inlet pipe 3, an internal air inlet pipe 4, a swirl generator 5, an upper baffle 6 for a nozzle, a lower baffle 7 for a nozzle, an outer sleeve 8, an inner sleeve 9, a central pipe 10, an exhaust pipe support 11, an exhaust pipe opening 12, a hot air furnace heating system 16 and a storage tank, wherein the storage tank includes a tank top 13, a tank wall 14 and a tank bottom 15.

[0045] The hot blast furnace heating system 16 is the output source of the preheated gas. The hot blast furnace heating system 16 is connected to the main air inlet pipe 1. The far end of the main air inlet pipe 1 in the air flow direction is connected to the distribution valve 2. The distribution valve 2 is respectively connected to the external air inlet pipe 3 and the internal air inlet pipe 4. The distribution valve 2 can adjust the flow of the two branch air inlet pipes.

[0046] The outer air inlet pipe 3 is connected to the outer sleeve 8, and the inner air inlet pipe 4 is connected to the inner sleeve 9. The outer sleeve 8, the inner sleeve 9 and the center pipe 10 are coaxially nested and extend into the interior of the storage tank. The outer sleeve 8, the inner sleeve 9 and the center pipe 10 are all circular tubes. An outer layer flow channel is formed between the outer sleeve 8 and the inner sleeve 9, and an inner layer flow channel is formed between the inner sleeve 9 and the center pipe 10. A swirl generator 5 is provided in the outer layer flow channel or the inner layer flow channel.

[0047] The flow channel of the swirl generator 5 is arranged as a swirl flow channel, while the flow channel without the swirl generator 5 is arranged as a regulating flow channel. In this embodiment, the swirl generator 5 is located in the inner layer flow channel, so that the distributed preheated gas is introduced into the gap between the inner sleeve 9 and the center tube 10 to form an annular swirl flow channel, and the distributed preheated gas is introduced into the gap between the outer sleeve 8 and the inner sleeve 9 to form an annular regulating flow channel.

[0048] The swirl generator 5 includes a cylinder and spiral blades. The cylinder is fixed to the central tube 10 or the inner sleeve 9. In this embodiment, the cylinder is coaxially fixed to the central tube 10. Several spiral blades are evenly arranged along the circumference of the outer side of the cylinder. The spiral channels formed between the spiral blades promote the formation of a swirl flow in the gas. A gap is left between the outer edge of the spiral blade and the inner sleeve 9 or the outer sleeve 8. In this embodiment, a gap is left between the spiral blade and the inner sleeve 9 to facilitate the installation of the swirl generator 5.

[0049] An outwardly extending upper nozzle baffle 6 is provided at the outlet of the outer sleeve 8, and a lower nozzle baffle 7 is provided on the central tube 10, located below the upper nozzle baffle 6. Preferably, the upper nozzle baffle 6 is a trumpet-shaped structure, and the lower nozzle baffle 7 is a platform-shaped structure. The trumpet-shaped structure of the upper nozzle baffle 6 is not limited to a circle and may also be a polygon. The upper nozzle baffle 6 and the lower nozzle baffle 7 are used to guide the jet at the nozzle, thereby forming different jet patterns to meet different preheating requirements.

[0050] Central pipe 10 serves as the central exhaust pipe. Outer sleeve 8, inner sleeve 9, and central pipe 10 extend from the center of the tank roof 13 into the tank and to the center of the tank bottom 15, allowing preheated gas to enter through the tank roof and exit at the bottom. Central pipe 10 is connected to the hot blast furnace heating system 16, and the exhausted gas flows back to the hot blast furnace heating system 16 for heating and recycling.

[0051] The central tube 10 is mounted on the bottom 15 of the storage tank via an exhaust pipe support 11 to maintain the stability of the central tube 10. The central tube 10 is provided with a plurality of exhaust pipe openings 12 at the bottom of the tank. After the high-temperature preheated gas enters the tank body, the original gas in the tank is squeezed out through the exhaust pipe and returned to the hot air furnace heating system 16.

[0052] Example 2

[0053] refer to Figures 1 to 6 As shown, a cyclone preheating method for a molten salt storage tank adopts the cyclone preheating device for a molten salt storage tank of Example 1.

[0054] Preheated gas is produced by the hot blast furnace heating system 16 and enters the distribution valve 2 through the main air inlet pipe 1. After being distributed by the distribution valve 2, the preheated gas flow rate flows into the inner and outer flow channels respectively. The flow channel where the swirl generator 5 is located serves as the swirl flow channel, while the flow channel where the swirl generator 5 is located does not serve as the regulating flow channel. In this embodiment, the swirl generator 5 is located within the inner flow channel, that is, the inner flow channel serves as the swirl flow channel, and the outer flow channel serves as the regulating flow channel.

[0055] The preheated gas in the swirl flow channel generates a rotating jet with a tangential velocity after passing through the swirl generator 5. The preheated gas in the regulating flow channel generates an irrotational jet without a tangential velocity. The rotating jet and the irrotational jet are mixed in the upper part of the nozzle to form a fusion swirl with a lower rotation intensity. The two jet flows are distributed through the distribution valve 2 to adjust the rotation intensity of the fusion swirl.

[0056] The swirl intensity of the fusion swirl is defined by the swirl number S_w calculated from the cross-sectional velocity distribution at a height 0.1 times the inner diameter of the outer sleeve above the connection between the nozzle upper baffle 6 and the outer sleeve 8:

[0057] ;

[0058] in, is the outer diameter of the annular flow channel, is the inner diameter of the annular flow channel, is the average axial velocity, is the average tangential velocity, is the medium density;

[0059] When all the preheated gas completely enters the nozzle through the regulating flow channel and no preheated gas is distributed to the swirl flow channel, the swirl number S_w=0, and the preheated gas forms an irrotational jet (the jet forms a Close Jet Flow). When it is sprayed onto the lower baffle 7 of the nozzle, it is guided by the lower baffle 7 to spray toward the large fillet weld between the tank bottom 15 and the tank wall 14, preheating the tank bottom edge and the large fillet weld area.

[0060] When the flow rate distributed by the swirl flow channel increases to a swirl number S_w greater than or equal to 0.2 and less than 0.6, the fused jet at the nozzle is affected by the rotation and expands circumferentially under the influence of the centrifugal effect (the jet forms Open Jet Flow-low swirl), spraying toward the lower part of the tank wall 14 and the large angle weld, preheating the lower area of ​​the tank wall.

[0061] When the flow rate distributed by the swirl flow channel increases to a swirl number S_w greater than or equal to 0.6 and less than 0.9, the merging jet at the nozzle is affected by the rotation, the centrifugal effect is further enhanced, and the merging jet further expands circumferentially. When the centrifugal effect breaks through the gas viscosity limitation, the jet is no longer stable and forms an open jet with high velocity fluctuations (jet formation Open Jet Flow-High swirl). At this time, the merging jet kinetic energy dissipates rapidly and will not be able to spray stably toward the wall. The preheated gas is quickly dispersed in the central area of ​​the tank.

[0062] When the flow rate distributed by the swirl flow channel is further increased to a swirl number S_w greater than or equal to 0.9, until all the preheated gas passes through the swirl flow channel to generate a rotating jet, the merging jet at the nozzle is affected by the centrifugal effect and the Coanda effect, forming a Coanda jet (jet forming a Coanda Jet Flow) that flows circumferentially along the upper baffle 6 of the nozzle. At this time, the merging jet is guided by the upper baffle 6 of the nozzle and flows toward the upper part of the tank wall 14. After the kinetic energy of the merging jet is dissipated near the tank wall, the preheated gas flows toward the tank top 13 under buoyancy drive, and at this time, the upper part of the tank wall 14 and the tank top 13 area are preheated.

[0063] To optimize the jet effect, the horizontal downward inclination angle d of the nozzle upper baffle 6 is greater than 10 degrees and less than 30 degrees. The connection between the nozzle upper baffle 6 and the outer sleeve 8 is rounded with a radius greater than 0.1 times the outer sleeve inner diameter to ensure the formation of a Coanda jet at high swirl numbers. The nozzle lower baffle 7 is positioned at an angle between 45 degrees and k-10 degrees with respect to the axial direction, where k is the angle between the connection point of the nozzle lower baffle 7 with the center pipe 10 and the large fillet weld between the tank bottom and the side wall, and the central axis. The outermost radius of the nozzle lower baffle 7 is smaller than the outermost radius of the nozzle upper baffle 6. The lowest height of the inner sleeve 9 is at least 0.5 times the outer sleeve inner diameter of the outer sleeve 8 at the connection point between the nozzle upper baffle 6 and the nozzle upper baffle 6.

[0064] The swirl generator 5 should be positioned at a controlled height, with the bottom of the swirl generator 5 at least 0.05 times the inner diameter of the outer sleeve 8 above the lowest point of the inner sleeve 9. The swirl generator 5 must generate sufficient rotational velocity to ensure that all preheated gas flows through the swirl channel into the storage tank, forming a Coanda jet at the nozzle. The junction between the top of the nozzle lower baffle 7 and the center tube 10 should be at least 1 times the inner diameter of the outer sleeve 8 below the lowest point of the nozzle upper baffle 6.

[0065] Example 3

[0066] refer to Figures 1 to 5 The figure shows a cyclone preheating device and method for a molten salt storage tank with a diameter of 27 meters and a height of 18 meters. Multiple temperature measurement points are installed within the tank to monitor the temperature of the tank wall and large fillet welds, providing real-time feedback. This allows for flexible adjustments to the preheating process based on the measurement results.

[0067] The preheating device (outer sleeve 8, inner sleeve 9, and center tube 10) extends into the tank through the center opening at the top. After preheating is complete, the device can be lifted directly out of the tank without interfering with the structure. All pipes are made of 347h stainless steel, with a thickness of 10mm. The distribution valve 2 is an electrically controlled valve connected to the control system. The outer air inlet pipe 3, inner air inlet pipe 4, outer sleeve 8, inner sleeve 9, and center tube 10 are all welded and sealed.

[0068] The swirl generator 5 is manufactured using CNC (Computer Numerical Controlled Precision Machining) technology. The inner side is welded to the outer wall of the central tube 10, and a gap is left between the outer side and the inner sleeve 9 to facilitate assembly. The outer sleeve 8 is welded to the upper nozzle baffle 6, and the inner surface is polished to ensure a smooth finish. The lower nozzle baffle 7 is welded to the central tube 10, and the joint is polished to a smooth finish. The central tube 10 extends into the tank bottom and is welded to the exhaust pipe support 11. The exhaust pipe support 11 is placed on the tank bottom, unfixed, to facilitate lifting the entire unit out after preheating.

[0069] In this example, the inner diameter of the central tube 10 is 500 mm, the inner diameter of the main air inlet pipe 1 is 400 mm, and the inner and outer air inlet pipes 4 and 3 each have an inner diameter of 250 mm. The inner sleeve 9 has an inner diameter of 700 mm, with a gap of 90 mm between it and the central tube 10. The outer sleeve 8 has an inner diameter of 750 mm, with a gap of 40 mm between it and the inner sleeve 9.

[0070] In this example, the cone-shaped surface of the nozzle lower baffle 7 has a 40-degree inclination angle and an outer radius of 710 mm. The nozzle upper baffle 6 has a 15-degree horizontal downward inclination angle and an outer radius of 910 mm, with a 120 mm fillet at the connection with the outer sleeve 8. The outer sleeve 8 is 1.5 m long, and the inner sleeve 9 is 2.5 m long.

[0071] In this example, the axial installation position of each component is determined by the height between the lowest point of the component and the bottom surface of the tank. The nozzle lower baffle 7 is 16.1m, the nozzle upper baffle 6 is 16.9m, the outer sleeve 8 is 17.15m, the inner sleeve 9 is 17.5m, and the swirl generator 5 is 17.6m.

[0072] In this embodiment, the preheating gas flow rate is 15,000 cubic meters per hour and 45,000 cubic meters per hour, and the preheating gas flow rate used during conventional preheating operation is 15,000 cubic meters per hour. The preheater temperature is set to be 50 degrees higher than the average temperature in the tank. The tank temperature is increased by 50 degrees every 24 hours on average to complete a heating cycle. The tank heating is completed within 7 days. During operation, the flow rate on both sides of the inner air inlet pipe 4 and the outer air inlet pipe 3 is changed by the distribution valve 2, thereby changing the fusion vortex swirl number S_w to change the popular shape of the swirl. During work, the swirl number S_w is adjusted to 0, 0.4, 0.8, and 1.2 in turn, and the time proportion of each stage is 30min, 30min, 120min, and 120min respectively. 6 hours is a small heating cycle. At the same time, when the temperature difference between the wall temperature measuring points is greater than 50 degrees, the preheating gas manifold is adjusted to the gas manifold corresponding to the area of ​​the measuring point where the low temperature occurs through the swirl number S_w, and the flow rate is adjusted to 45,000 cubic meters per hour. The area is heated for 15 minutes and then returns to the normal operation mode.

[0073] In this embodiment, the preheating working medium can be air, carbon dioxide, or at least one of the three rare gases argon, nitrogen, and helium.

[0074] Other details are the same as in Example 2.

[0075] The aforementioned basic examples and their further selected examples can be freely combined to form multiple embodiments, all of which are embodiments that can be adopted and claimed for protection in this application. In this application, each selected example can be arbitrarily combined with any other basic examples and selected examples.

[0076] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A molten salt storage tank cyclone preheating method, using a molten salt storage tank cyclone preheating device, the device comprising a main air inlet pipe (1), characterized in that: The main air inlet pipe (1) is connected to the distribution valve (2), and the distribution valve (2) is connected to the outer air inlet pipe (3) and the inner air inlet pipe (4) respectively. The outer air inlet pipe (3) is connected to the outer sleeve (8), and the inner air inlet pipe (4) is connected to the inner sleeve (9). The outer sleeve (8), the inner sleeve (9) and the central pipe (10) are coaxially nested and extend into the interior of the storage tank. An outer layer flow channel is formed between the outer sleeve (8) and the inner sleeve (9), and an inner layer flow channel is formed between the inner sleeve (9) and the central pipe (10). A swirl generator (5) is provided in the outer layer flow channel or the inner layer flow channel. An outward-extending nozzle upper baffle (6) is provided at the outlet of the outer sleeve (8), and a nozzle lower baffle (7) located below the nozzle upper baffle (6) is provided on the central pipe (10); The preheating method comprises the following steps: preheating gas enters the distribution valve (2) through the main air inlet pipe (1), and the distribution valve (2) distributes the preheating gas flow rate and then flows into the inner layer flow channel and the outer layer flow channel respectively; the flow channel where the swirl generator (5) is arranged serves as the swirl flow channel, and the flow channel where the swirl generator (5) is not arranged serves as the regulating flow channel; the preheating gas in the swirl flow channel generates a swirling jet with a tangential velocity after passing through the swirl generator (5); the preheating gas in the regulating flow channel generates an irrotational jet without a tangential velocity; the swirling jet and the irrotational jet are mixed in the upper section of the nozzle to form a fusion swirl with a relatively low swirl intensity; the swirl intensity of the fusion swirl is adjusted by distributing the two jet flows through the distribution valve (2); The swirl intensity of the fusion swirl is defined by the swirl number S_w calculated from the cross-sectional velocity distribution at a height 0.1 times the inner diameter of the outer sleeve above the connection between the nozzle upper baffle (6) and the outer sleeve (8): ； in, is the outer diameter of the annular flow channel, is the inner diameter of the annular flow channel, is the average axial velocity, is the average tangential velocity, is the medium density; When all the preheated gas completely enters the nozzle through the regulating flow channel and the preheated gas is not distributed to the swirl flow channel, the swirl number S_w=0, and the preheated gas forms an irrotational jet. When it is sprayed to the lower baffle (7) of the nozzle, it is guided by the lower baffle (7) to spray toward the large angle weld between the tank bottom (15) and the tank wall (14), and preheats the tank bottom edge and the large angle weld area; when the flow rate distributed by the swirl flow channel increases to a swirl number S_w greater than or equal to 0.2 and less than 0.6, the fused jet at the nozzle is affected by the rotation and expands circumferentially under the influence of the centrifugal effect, and sprays toward the lower part of the tank wall (14) and the large angle weld, and preheats the lower area of ​​the tank wall; when the flow rate distributed by the swirl flow channel increases to a swirl number S_w greater than or equal to 0.6 and less than 0.9, the fused jet at the nozzle is affected by the rotation, the centrifugal effect is further strengthened, and the fused jet further expands circumferentially. When the centrifugal effect breaks through the gas viscosity limit, the jet is no longer stable and forms an open jet with high velocity fluctuation. At this time, the fusion jet kinetic energy dissipates rapidly and cannot be stably sprayed to the wall. The preheated gas is quickly dispersed in the central area of ​​the tank. When the flow rate distributed by the swirl flow channel is further increased to a swirl number S_w greater than or equal to 0.9, until all the preheated gas passes through the swirl flow channel to generate a rotating jet, the fusion jet at the nozzle is affected by the centrifugal effect and the Coanda effect, forming a Coanda jet flowing circumferentially along the nozzle upper baffle (6). At this time, the fusion jet is guided by the nozzle upper baffle (6) and flows to the upper part of the tank wall (14). In the area near the tank wall, after the fusion jet kinetic energy dissipates, the preheated gas flows to the tank top (13) under buoyancy drive. At this time, the upper part of the tank wall (14) and the tank top (13) area are preheated.

2. The cyclone preheating method for a molten salt storage tank according to claim 1, characterized in that: The swirl generator (5) comprises a cylinder and spiral blades. The cylinder is fixed on a central tube (10) or an inner sleeve (9), and a plurality of spiral blades are evenly arranged on the outer side of the cylinder along the circumferential direction.

3. The cyclone preheating method for a molten salt storage tank according to claim 1 or 2, characterized in that: The swirl generator (5) is located in the inner flow channel.

4. The cyclone preheating method for a molten salt storage tank according to claim 1, characterized in that: The upper baffle plate (6) of the nozzle is a trumpet-shaped structure, and the lower baffle plate (7) of the nozzle is a table-shaped structure.

5. The cyclone preheating method for a molten salt storage tank according to claim 1, characterized in that: The central tube (10) is a central exhaust pipe. The outer sleeve (8), the inner sleeve (9) and the central tube (10) extend into the storage tank from the center of the tank top (13), and the central tube (10) extends to the center of the tank bottom (15).

6. The cyclone preheating method for a molten salt storage tank according to claim 5, characterized in that: The central tube (10) is arranged on the bottom (15) of the storage tank via an exhaust pipe support (11), and a plurality of exhaust pipe openings (12) located at the bottom of the tank are opened on the central tube (10).

7. The cyclone preheating method for a molten salt storage tank according to claim 1, characterized in that: It also includes a hot blast furnace heating system (16), the hot blast furnace heating system (16) is connected to the main air inlet pipe (1), and the central pipe (10) is connected to the hot blast furnace heating system (16).

8. The cyclone preheating method for a molten salt storage tank according to claim 1, characterized in that: The horizontal downward inclination angle d of the nozzle upper baffle (6) is greater than 10 degrees and less than 30 degrees. The connection between the nozzle upper baffle (6) and the outer sleeve (8) is rounded, and the rounded corner radius is greater than 0.1 times the inner diameter of the outer sleeve; the nozzle lower baffle (7) and the axial angle are between 45 degrees and k-10 degrees, where k is the angle between the connection point of the nozzle lower baffle (7) and the center pipe (10) and the connection line of the large angle weld between the bottom and the side wall of the tank and the central axis; the outermost radius of the nozzle lower baffle (7) is The outermost radius of the nozzle upper baffle (6) is smaller than that of the inner sleeve (9); the lowermost height of the inner sleeve (9) is higher than the outer sleeve (8) and the nozzle upper baffle (6) by at least 0.5 times the inner diameter of the outer sleeve (8); the bottom of the swirl generator (5) is higher than the lowermost point of the inner sleeve (9) by at least 0.05 times the inner diameter of the outer sleeve (8); the top of the nozzle lower baffle (7) and the center tube (10) are lower than the lowest point of the nozzle upper baffle (6) by at least 1 times the inner diameter of the outer sleeve (8).

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