A steel slag thermal storage system and method based on dual-pipe pneumatic conveying

Abstract

This invention provides a high-temperature solid thermal storage system and method based on dual-pipe pneumatic conveying, belonging to the field of solid particle thermal storage technology. The system includes a cold powder silo, a preheater, a delivery tank, a fluidized bed heater, a cyclone separator, a hot powder silo, a moving bed heat exchanger, and a hoist. Pretreated spherical steel slag is used as the thermal storage medium, and low-speed dense-phase conveying is achieved through a dual-pipe pneumatic conveying pipeline. The inner pipe opening is actively anti-clogging. The fluidized bed heater and moving bed heat exchanger are separated into zones to achieve rapid thermal storage and stable thermal release, respectively. The preheater utilizes the high-temperature flue gas after cyclone separation to preheat the cold steel slag, forming a highly efficient cascaded waste heat recovery. This invention significantly improves the conveying stability and pipeline life of high-density particles, reduces energy consumption by approximately 30%, and simultaneously achieves high-value-added resource utilization of steel slag solid waste. It combines rapid thermal storage and high-quality thermal release capabilities, saving 10-20% of fuel, and is suitable for industrial waste heat recovery, power grid peak shaving, and other fields.

Description

Technical Field

[0001] This invention belongs to the field of solid particle thermal storage technology, specifically relating to a steel slag thermal storage system and method based on double-pipe pneumatic conveying. Background Technology

[0002] Solid particle thermal energy storage technology is considered one of the most promising thermal energy storage technologies in fields such as concentrated solar power (CSP), industrial waste heat recovery, and grid peak shaving due to its advantages such as low cost, wide temperature range (from room temperature to above 1500℃), high thermal density, and long service life. In recent years, several MWh-level high-temperature solid particle thermal energy storage pilot plants have been built in China, with the highest operating temperature reaching 1500℃ and a thermal density more than three times that of molten salt. In the field of industrial waste heat recovery, moving bed, fluidized bed, and packed bed are the three mainstream types of solid particle thermal energy storage reactors.

[0003] Researchers have attempted to combine pneumatic conveying technology with solid particle thermal storage technology. For example, one patent application discloses a high-efficiency transport, heat exchange, and heating system that combines pneumatic conveying with solid particle thermal storage, achieving an energy storage density of 700-900 MJ / m³. Another patent discloses a fluidized bed solid particle thermal storage and release system based on pneumatic conveying.

[0004] However, the aforementioned existing technologies have the following shortcomings: 1) Bottleneck of pneumatic conveying of high-hardness, high-density particles. When high-density, high-hardness solid particles (such as magnetite and steel slag) are used as the heat storage medium, the high-speed moving particles cause severe impact and friction on the inner wall of the pipeline, resulting in severe wear of the pipeline; at the same time, high-density particles are very easy to deposit and clog during long-distance conveying, especially in the horizontal and vertical lifting sections, which seriously affects the continuous operation of the system.

[0005] 2) In the existing technology, the gas being transported is usually room temperature compressed air. After contacting high temperature particles, it needs to be dusted and discharged. The heat carried by the particles is dissipated with the exhaust gas, which reduces the thermal efficiency of the system.

[0006] 3) Existing technologies mostly use a single fluidized bed or moving bed heat exchanger to simultaneously perform heat storage and heat release functions, failing to optimize the design according to the differentiated needs of heat storage (requiring rapid heating) and heat release (requiring stable output).

[0007] 4) Steel slag, as a bulk industrial solid waste, possesses good thermal stability and low cost after proper pretreatment, making it an ideal low-cost heat storage medium. However, current technology has not reported on the integrated design of pretreated spherical steel slag as a circulating heat storage medium with pneumatic conveying and heat exchange systems. The high bulk density (2.2-2.5 t / m³) and high hardness of steel slag place more stringent requirements on the conveying system than on natural sand and gravel.

[0008] 5) Insufficient utilization of waste heat from flue gas. Existing technologies for utilizing waste heat from high-temperature flue gas mostly rely on single-stage heat exchange, failing to achieve multi-stage cascade recovery, including heat storage in the high-temperature section, preheating of cold materials in the medium-temperature section, and production of hot water / steam in the low-temperature section.

[0009] Therefore, how to achieve long-distance stable transportation and efficient heat exchange of high-hardness, high-density solid heat storage particles, while taking into account the differentiated needs of rapid heat storage and stable heat release in the same system, and at the same time realizing high-value-added resource utilization of steel slag and multi-stage cascade recovery of flue gas waste heat, are technical problems that urgently need to be solved in this field. Summary of the Invention

[0010] To address the problems existing in the prior art, this invention provides a steel slag heat storage system and method based on double-pipe pneumatic conveying, which solves the problems of high wear and easy blockage when conveying high-hardness and high-density particles, heat loss during the conveying process, limited heat exchangers used, and insufficient waste heat recovery from flue gas in solid heat storage systems based on pneumatic conveying.

[0011] To achieve the above objectives, in a first aspect, the present invention provides a high-temperature solid thermal storage system based on a double-pipe pneumatic conveying system, comprising a cold powder silo, a preheater, a sending tank, a fluidized bed heater, a cyclone separator, a hot powder silo, a moving bed heat exchanger, and a hoist; the cold powder silo, preheater, sending tank, fluidized bed heater, cyclone separator, hot powder silo, moving bed heat exchanger, and hoist are sequentially connected along the flow direction of the solid particles; an industrial flue gas inlet is provided on the fluidized bed heater, and an air inlet is provided on the sending tank and connected to the air outlet of an air compressor station; the cyclone separator, preheater, dust collector, and chimney are sequentially connected along the flow direction of the flue gas; the sending tank and the fluidized bed heater are connected by a double-pipe pneumatic conveying pipeline, which consists of an outer pipe and an inner pipe coaxially disposed inside the outer pipe, the inner pipe having multiple openings spaced apart along its length, with the openings facing downwards; the solid thermal storage particles are pretreated spherical steel slag with a particle size of 0.5-2 mm.

[0012] Furthermore, the cold powder silo is used to store low-temperature solid heat storage particles. The cold powder silo uses a ceramic lining as a wear-resistant material with a temperature range of -50℃ to 700℃; it uses a rock wool pipe shell as a heat insulation material with a temperature range of <400℃; and it uses basalt as an outer protective material.

[0013] Furthermore, the hot powder silo is used to store high-temperature solid heat storage particles. The hot powder silo uses silicon carbide coating as wear-resistant material, with a temperature resistance of up to 1600℃, aluminum silicate fiber as insulation material, with a temperature resistance range of 1000℃-1260℃, and basalt as outer protective material.

[0014] Furthermore, the double-pipe pneumatic conveying pipeline uses silicon carbide as a wear-resistant material with a temperature resistance of up to 1600℃, aluminum silicate fiber as a heat insulation material with a temperature resistance range of 1000℃-1260℃, and basalt as an outer protective material. Furthermore, the fluidized bed heater is used for heat exchange between low-temperature solid heat storage particles and high-temperature flue gas. The flue gas enters from the side or bottom, while the solid heat storage particles enter from the top. The pressure at the top of the fluidized bed heater is higher than the inlet pressure of the cyclone separator. The moving bed heat exchanger 7 is used for heat release from high-temperature solid heat storage particles. The high-temperature solid heat storage particles enter from the top using gravity, while the heated fluid enters from the bottom.

[0015] Furthermore, the preheater is used to recover the waste heat in the flue gas after heat exchange. The low-temperature solid heat storage material is preheated by absorbing the waste heat in the separated flue gas, which reduces energy consumption and realizes the gradient recovery of waste heat. The sending tank is used to transport the solid heat storage particles with compressed air. The compressed air carries the preheated solid heat storage particles through a double-pipe pneumatic conveying pipeline to the fluidized bed heat exchanger. The cyclone separator is used to separate the heated high-temperature solid heat storage particles and the medium- and low-temperature flue gas. The high-temperature solid heat storage particles enter the hot powder bin for storage by gravity, and the medium- and low-temperature flue gas enters the preheater to preheat the low-temperature solid heat storage particles.

[0016] Furthermore, high-temperature resistant airlock unloading valves are installed at the bottom solid outlet of the cyclone separator, the top inlet of the hot powder bin, and the side inlet of the cold powder bin. The high-temperature resistant airlock unloading valve includes a heat-resistant steel dividing wheel and a housing; the dividing plate of the dividing wheel is provided with wear-resistant blades; a ring shaft sealing structure is provided at the shaft extension position on the end plate of the housing, and the ring shaft sealing structure is connected to the air source to form an air film seal through compressed air; the bearing is set on the support end plate outside the housing and at a distance from the end plate of the housing; the working temperature of the heat-resistant steel dividing wheel is ≥800℃.

[0017] Furthermore, the elevator is a bucket elevator, which uses wear-resistant steel plates or wear-resistant ceramics as lining, and has an arc-shaped bottom structure. Buffer devices are installed at the feed and discharge points of the bucket elevator.

[0018] Furthermore, a waste heat recovery device is installed before the dust collector.

[0019] Furthermore, a flue gas circuit is connected between the fluidized bed heater and the preheater.

[0020] Secondly, the present invention provides a heat storage method based on the above-mentioned steel slag heat storage system based on double-pipe pneumatic conveying, comprising: Solid thermal storage particles are stored in a cold powder silo. Preheating: Low-temperature solid heat storage particles from the cold powder silo are fed into the preheater, and 600 from the cyclone separator... 800℃ high-temperature flue gas preheats low-temperature solid heat storage particles to 300℃ 400℃; After being transported, the preheated solid heat storage particles enter the delivery tank and are then transported to the fluidized bed heater via a double-pipe pneumatic conveying pipeline in a low-speed dense phase manner. In fluidized bed heaters, solid heat storage particles directly contact and exchange heat with industrial waste gas, heating it to 700°C. 800℃; Separation: The gas-solid mixture enters the cyclone separator, the separated high-temperature solid heat storage particles fall into the hot powder bin, and the high-temperature flue gas is sent to the preheater for preheating. Heat release: the high-temperature solid heat storage particles in the hot powder silo flow into the moving bed heat exchanger by gravity, where they exchange heat with the low-temperature air in a counter-current manner. The air is then heated and supplied to the user. The solid heat storage particles, after being cooled and released from heat, are then sent back to the cold powder silo via an elevator, completing the cycle.

[0021] Compared with the prior art, the present invention has at least the following beneficial effects: By using a conveying tank combined with a double-pipe system, stable long-distance and high-height conveying of high-density steel slag particles can be achieved. The conveying air velocity is ≤12m / s, the service life of the pipeline is extended by 2-3 times, energy consumption is reduced by about 30%, and the double-pipe system can actively clear blockages. The system adopts a zoned design, with fluidized bed heating to achieve rapid heat storage and a heat transfer coefficient of 200-500 W / m²·K, and moving bed heat release to achieve stable output and stable outlet temperature, taking into account both rapid capture of waste heat and stable heating demand. Pre-treated spherical steel slag with a diameter of 0.5-2mm is used. The spherical shape improves fluidity and reduces wear. The steel slag is inexpensive, enabling high-value utilization of industrial solid waste. The preheater utilizes high-temperature flue gas (600-800℃) to preheat low-temperature steel slag (150-200℃) to 300-400℃, saving 10-20% of fuel; and a waste heat boiler can be connected in series after the preheater to further recover medium and low-temperature waste heat. The hot powder silo and the moving bed rely on gravity for material feeding, requiring no additional power; the control system achieves fully automated operation and fault early warning. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of a system for realizing heat storage and release of steel slag based on double-pipe pneumatic conveying according to the present invention; Figure 2 This is a schematic diagram of a workable method according to the present invention.

[0023] In the diagram: 1-Cold powder silo; 2-Preheater; 3-Sending tank; 4-Fluidized bed heat exchanger; 5-Cyclone separator; 6-Hot powder silo; 7-Moving bed heat exchanger; 8-Bucket elevator; 9-Dust collector; 10-Chimney; 11-Air compressor station. Detailed Implementation

[0024] 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, not all, of the embodiments of the present invention. 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.

[0025] like Figure 1 As shown, this embodiment provides a high-temperature solid thermal storage system based on dual-pipe pneumatic conveying, including a cold powder silo 1, a preheater 2, a conveying tank 3, a fluidized bed heater 4, a cyclone separator 5, a hot powder silo 6, a moving bed heat exchanger 7, a bucket elevator 8, a dust collector 9, a chimney 10, an air compressor station 11, and an airlock discharge valve. The cold powder silo 1 is used to store low-temperature solid thermal storage particles. In this embodiment, the solid thermal storage particles are pretreated spherical steel slag with a particle size of 0.5 mm. 2mm, temperature approximately 150 200℃. The outlet of the cold powder silo 1 is connected to the inlet of the preheater 2 via a solid conveying pipeline. A rotary discharge valve is installed on the solid conveying pipeline to control the feed rate and prevent airflow disturbance. The preheater 2 is a gas-solid direct contact heat exchanger; its gas inlet is connected to the gas outlet of the cyclone separator 5 to receive gas from the cyclone separator 5. High-temperature flue gas of 800℃. Preheater 2 uses this high-temperature flue gas to preheat the solid heat storage particles fed into the cold powder silo 1, raising their temperature to 300℃. 400℃. The outlet of preheater 2 is connected to the inlet of sending tank 3. Sending tank 3 is a silo pump type pressure sender, and the air inlet of sending tank 3 is connected to the air outlet of air compressor station 11. Compressed air supplied by air compressor station 11 enters sending tank 3, and the preheated solid heat storage particles are conveyed at a conveying air velocity of 5. A low-speed, dense-phase method of 12 m / s is used to pressurize the double-pipe pneumatic conveying pipeline.

[0026] The dual-tube pneumatic conveying pipeline consists of an outer tube and an inner tube coaxially disposed inside the outer tube. Multiple openings are spaced along the length of the bottom of the inner tube. When material deposits and causes blockage in the outer tube, compressed air automatically flows through the inner tube and is ejected at high speed from the opening downstream of the blockage, disturbing the deposited material and actively clearing the blockage. The outlet of the dual-tube pneumatic conveying pipeline is connected to the inlet of the fluidized bed heater 4.

[0027] The fluidized bed heater 4 is equipped with a gas distribution plate at its bottom, and its gas inlet is connected to an industrial flue gas source with a temperature ≤800℃. Solid heat storage particles are in direct contact with the industrial flue gas in the fluidized bed heater 4, are in a fluidized state, and are rapidly heated to 700℃. 800℃. The outlet of the fluidized bed heater 4 is connected to the inlet of the cyclone separator 5 through a gas pipeline.

[0028] The pressure at the top of the fluidized bed heater is higher than the inlet pressure of the cyclone separator. Driven by the pressure difference, the gas-solid mixture automatically flows from the fluidized bed heater 4 to the cyclone separator 5 without the need for an additional pneumatic conveying device.

[0029] The cyclone separator 5 separates the high-temperature flue gas from the solid heat storage particles: the separated high-temperature flue gas is sent to the preheater 2 through its gas outlet to preheat the cold steel slag; the separated high-temperature steel slag particles fall into the hot powder bin 6 through its bottom solid outlet.

[0030] High-temperature resistant airlock unloading valves are installed at the bottom solid outlet of cyclone separator 5, the top inlet of hot powder bin 6, and the side inlet of cold powder bin 1. The high-temperature resistant airlock unloading valve includes a heat-resistant steel dividing wheel and a housing. The dividing plate of the dividing wheel is provided with wear-resistant blades. A ring shaft sealing structure is provided at the shaft extension position on the end plate of the housing. The ring shaft sealing structure is connected to the air source and forms an air film seal by compressed air. The bearing is set on the support end plate outside the housing and at a distance from the end plate of the housing. The working temperature of the heat-resistant steel dividing wheel is ≥800℃.

[0031] Hot powder silo 6 is an insulated storage tank used to store 700 Solid heat storage particles at 800℃. The bottom outlet of the hot powder silo 6 is connected to the top inlet of the moving bed heat exchanger 7 via a chute, and the installation height of the hot powder silo 6 is higher than that of the moving bed heat exchanger 7, so that the high-temperature steel slag particles flow into the moving bed heat exchanger 7 by gravity without the need for additional power.

[0032] The moving bed heat exchanger 7 is a counter-current moving bed heat exchanger. Its top inlet receives high-temperature steel slag particles, its bottom air inlet is connected to a low-temperature air source, and its top air outlet is connected to the user's heating equipment. The solid heat storage particles move slowly downwards within the moving bed heat exchanger 7, exchanging heat counter-currently with the low-temperature air (approximately 25°C) entering from the bottom. The air is heated to 500°C. The steel slag particles are supplied to users after reaching 700℃ and then cooled to approximately 150℃. It is discharged from the bottom outlet after reaching 200℃.

[0033] The discharge port of the moving bed heat exchanger 7 is connected to the feed port of the bucket elevator 8. The bucket elevator 8 is lined with wear-resistant steel plates and lifts the cooled solid heat storage particles back to the cold powder silo 1 to complete one cycle.

[0034] 200 kW discharged from preheater 2 Medium-temperature flue gas at 300℃ enters the dust collector 9 for purification, and the purified flue gas is discharged through the chimney 10. To make full use of waste heat, a waste heat recovery device (not shown in the figure) can be connected in series before the dust collector 9 to generate hot water or steam.

[0035] The moving bed heat exchanger is a two-stage moving bed heat exchanger. The interior of the moving bed heat exchanger is divided into an upper section and a lower section. The upper section is a dense phase zone with buried tubes and a vibrating buried tube layer inside. The bottom of the lower section is equipped with an air distribution device. The gas inlet of the air distribution device is connected to a compressed air source. By introducing loose air, the flowability of particles is improved, and solid heat storage particles are prevented from accumulating and clogging in the lower section.

[0036] The three-layer composite double-tube structure includes a wear-resistant inner lining, an insulation layer, and an outer protective layer. Preferably, from the inside out, the layers are a silicon carbide wear-resistant inner lining, an aluminum silicate fiber insulation layer, and a basalt protective layer.

[0037] It is also equipped with a control system that automatically adjusts the feeding frequency of the feeding tank, the flow rate of the fluidized bed flue gas, and the flow rate of the moving bed cooling medium based on temperature, pressure, and flow signals.

[0038] A fluidization transition section is designed at the outlet of the sending tank (3). An auxiliary airflow is introduced into the fluidization transition section so that the preheated steel slag particles reach the fluidization state before entering the double-tube system. The inner tube opening of the double-tube system is designed as a one-way throttling orifice so that the airflow ejected can not only disturb the sediment, but also provide continuous air cushion support for the dense phase particles flowing along the lower wall of the outer tube, thus optimizing the conveying state from low-speed dense phase to quasi-continuous ultra-low-speed dense phase.

[0039] Pressure sensors are installed below the gas distribution plate of the fluidized bed heater 4 and in the particle bed of the moving bed heat exchanger 7. When the system detects a decrease in fluidized bed pressure or an increase in moving bed discharge port pressure, the control system automatically adjusts the output pressure of the air compressor station 11 or the feeding frequency of the delivery tank 3 to achieve on-demand feeding. The temperature and flow rate of industrial waste heat sources often fluctuate. The adaptive system can dynamically adjust the circulation volume of steel slag according to the actual heat load to avoid over-transportation or insufficient supply, ensuring the matching of heat storage and heat release processes, and avoiding operation at rated power during off-peak hours, thus saving compressed air and transportation energy consumption. At the same time, it prevents the risk of fluidized bed cavitation due to low material level or moving bed blockage due to excessive feeding.

[0040] The elbows, tees, and vertical sections of the double-pipe pneumatic conveying pipeline, as well as the wear-resistant lining of the bucket elevator 8, are designed as modular components that are easy to disassemble and replace. The wear-resistant guide plates inside the moving bed heat exchanger 7 can also be modularly designed. By modularizing easily worn parts, when wear occurs, there is no need to shut down the machine, cut, or weld the entire piping system; only the local module needs to be replaced. This significantly reduces maintenance time.

[0041] A composite heat exchanger is added after preheater 2 and before dust collector 9. The composite heat exchanger includes two independent heat exchange channels: flue gas-air and flue gas-water. Medium-temperature flue gas at 200-300℃ first enters the flue gas-air side, preheating the required combustion air or return air for the moving bed to 150-200℃, and then enters the flue gas-water side, heating industrial water to 80-90℃ for heating or domestic hot water.

[0042] like Figure 2 As shown, the present invention also provides a heat storage method based on the above-mentioned steel slag heat storage system based on double-pipe pneumatic conveying, including storage, preheating, conveying, heat storage, separation, heat release, and circulation processes. The system operation method of this embodiment includes the following steps: Storage: For particles with a diameter of 0.5 mm... 2mm spherical steel slag is stored in cold powder silo 1.

[0043] Preheating: The low-temperature steel slag in cold powder silo 1 is fed into preheater 2, utilizing the high-temperature flue gas 600 from cyclone separator 6. Preheat it to 300℃ at 800℃ 400℃.

[0044] Conveying: The preheated steel slag enters the sending tank 3 and is transported to the fluidized bed heater 4 through a double-pipe pneumatic conveying pipeline in a low-speed dense phase manner.

[0045] Heat storage: In fluidized bed heater 4, steel slag and industrial waste gas exchange heat directly at ≤800℃, and are heated to 700℃. 800℃.

[0046] Separation: The gas-solid mixture enters the cyclone separator 5, the separated high-temperature steel slag falls into the hot powder bin 6, and the high-temperature flue gas is sent to the preheater 2 for the preheating step.

[0047] Heat release: The high-temperature steel slag in the hot powder silo 6 flows into the moving bed heat exchanger 7 by gravity, where it exchanges heat with the low-temperature air in a countercurrent manner. The heated air is then supplied to the user.

[0048] Circulation: After the steel slag is cooled and heated, it is sent back to the cold powder silo 1 via bucket elevator 8, completing the circulation.

[0049] This invention provides a steel slag thermal storage system and method based on dual-pipe pneumatic conveying, representing an improvement and innovation over existing solid particle thermal storage technologies. The main bottlenecks of existing technologies are: severe wear and blockage of the solid particles used for thermal storage during pneumatic conveying; furthermore, conventional system designs fail to optimize for the differentiated thermodynamic requirements of thermal storage and release, resulting in insufficient efficiency or unstable output; and waste heat recovery is also relatively crude. This invention provides a solution: in the conveying stage, a dual-pipe pneumatic conveying pipeline is used to actively clear accumulated and blocked materials, and combined with a low-speed dense-phase conveying mode, it solves the problem of conveying high-density, high-hardness particles, improving the system's operational reliability and economy. Secondly, in the heat exchange stage, a fluidized bed heater is used for rapid thermal storage to cope with intermittent, high-temperature heat sources; a moving bed heat exchanger is used for stable heat release, providing stable and controllable high-quality thermal energy, enabling the system to simultaneously meet the dual requirements of efficient energy storage and stable energy release. Finally, in the energy management stage, a multi-stage waste heat recovery system is constructed by directly preheating cold steel slag using high-temperature flue gas through a preheater, minimizing energy loss. Simultaneously, this invention selects and pre-treats spherical steel slag as the heat storage medium, providing a high-value-added utilization method for bulk industrial solid waste and significantly reducing energy storage costs, making the solution practically feasible.

[0050] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A high-temperature solid thermal storage system based on dual-pipe pneumatic conveying, characterized in that, The system includes a cold powder silo (1), a preheater (2), a delivery tank (3), a fluidized bed heater (4), a cyclone separator (5), a hot powder silo (6), a moving bed heat exchanger (7), and a hoist. The cold powder silo (1), preheater (2), delivery tank (3), fluidized bed heater (4), cyclone separator (5), hot powder silo (6), moving bed heat exchanger (7), and hoist are connected sequentially along the direction of solid particle flow. An industrial flue gas inlet is located on the fluidized bed heater (4), and the delivery tank (3) is... The air inlet is connected to the air outlet of the air compressor station (11). The cyclone separator (5), preheater (2), dust collector (9) and chimney (10) are connected in sequence along the flue gas flow direction. The sending tank (3) and the fluidized bed heater (4) are connected by a double-pipe pneumatic conveying pipeline. The double-pipe pneumatic conveying pipeline consists of an outer pipe and an inner pipe coaxially set inside the outer pipe. The inner pipe has multiple openings spaced apart along its length, with the openings facing downwards. The solid heat storage particles are pretreated spherical steel slag with a particle size of 0.5-2mm.

2. The high-temperature solid thermal storage system based on dual-pipe pneumatic conveying according to claim 1, characterized in that, The cold powder silo (1) is used to store low-temperature solid heat storage particles. The cold powder silo (1) uses ceramic lining as wear-resistant material with a temperature range of 50℃-700℃; uses rock wool pipe shell as insulation material with a temperature range of <400℃; and uses basalt as outer protective material.

3. The high-temperature solid thermal storage system based on dual-pipe pneumatic conveying according to claim 1, characterized in that, The hot powder silo (6) is used to store high-temperature solid heat storage particles. The hot powder silo (6) uses silicon carbide coating as wear-resistant material, with a temperature resistance of up to 1600℃. It uses aluminum silicate fiber as insulation material, with a temperature resistance range of 1000℃-1260℃. It uses basalt as outer protective material.

4. A high-temperature solid thermal storage system based on dual-pipe pneumatic conveying according to claim 1, characterized in that, The double-pipe pneumatic conveying pipeline uses silicon carbide as a wear-resistant material with a temperature resistance of up to 1600℃, aluminum silicate fiber as a heat insulation material with a temperature resistance range of 1000℃-1260℃, and basalt as an outer protective material.

5. A high-temperature solid thermal storage system based on dual-pipe pneumatic conveying according to claim 1, characterized in that, The fluidized bed heater (4) is used for heat exchange between low-temperature solid heat storage particles and high-temperature flue gas. The flue gas enters from the side or bottom, and the solid heat storage particles enter from the top. The pressure at the top of the fluidized bed heater (4) is higher than the inlet pressure of the cyclone separator. The moving bed heat exchanger 7 is used for heat release of high-temperature solid heat storage particles. The high-temperature solid heat storage particles enter from the top by gravity, and the heated fluid enters from the bottom.

6. A high-temperature solid thermal storage system based on dual-pipe pneumatic conveying according to claim 1, characterized in that, High-temperature resistant airlock unloading valves are provided at the bottom solid outlet of the cyclone separator (5), the top inlet of the hot powder bin (6), and the side inlet of the cold powder bin (1). The high-temperature resistant airlock unloading valve includes a heat-resistant steel dividing wheel and a housing. The dividing plate of the dividing wheel is provided with wear-resistant blades. The shaft extension position on the end plate of the housing is provided with a ring shaft sealing structure, which is connected to the air source and forms an air film seal by compressed air. The bearing is set on the support end plate outside the housing and is kept at a distance from the end plate of the housing. The working temperature of the heat-resistant steel dividing wheel is ≥800℃.

7. A high-temperature solid thermal storage system based on dual-pipe pneumatic conveying according to claim 1, characterized in that, The elevator is a bucket elevator (8), which is made of wear-resistant steel plate or wear-resistant ceramic as inner lining, and has an arc-shaped bottom structure. Buffer devices are set at the feed and discharge points of the bucket elevator (8).

8. A high-temperature solid thermal storage system based on dual-pipe pneumatic conveying according to claim 1, characterized in that, A waste heat recovery device is installed in front of the dust collector (9).

9. A high-temperature solid thermal storage system based on dual-pipe pneumatic conveying according to claim 1, characterized in that, A flue gas circuit is connected between the fluidized bed heater (4) and the preheater (2).

10. A heat storage method based on the above-mentioned steel slag heat storage system based on double-pipe pneumatic conveying, characterized in that, include: Storage: Solid heat storage particles are stored in a cold powder silo (1); Preheating: Low-temperature solid heat storage particles in the cold powder silo (1) are fed into the preheater (2), and 600 ppm of the cyclone separator (6) is used for preheating. 800℃ high-temperature flue gas preheats low-temperature solid heat storage particles to 300℃ 400℃; After being transported and preheated, the solid heat storage particles enter the delivery tank (3) and are transported to the fluidized bed heater (4) through the double-pipe pneumatic conveying pipeline in a low-speed dense phase manner. In the fluidized bed heater (4), solid heat storage particles directly contact and exchange heat with industrial waste gas, heating it to 700°C. 800℃; Separation: The gas-solid mixture enters the cyclone separator (5), the separated high-temperature solid heat storage particles fall into the hot powder bin (6), and the high-temperature flue gas is sent to the preheater (2) for preheating; Heat is released, and the high-temperature solid heat storage particles in the hot powder bin (6) flow into the moving bed heat exchanger (7) by gravity, where they exchange heat with the low-temperature air in a countercurrent manner. The air is then heated and supplied to the user. The solid heat storage particles, after being cooled and released from heat, are returned to the cold powder silo (1) by an elevator, thus completing the cycle.

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