Fluidized bed cold storage system based on direct heat exchange

Abstract

The utility model discloses a fluidized bed cold storage system based on direct heat exchange. The fluidized bed cold storage system comprises a fluidized bed unit, a particle storage tank unit and a gas-solid separator unit, wherein the fluidized bed unit, the particle storage tank unit and the gas-solid separator unit are communicated through pipelines to form closed circulation and realize strong convection heat exchange of gas-solid-liquid multiphase direct contact; a feed port of the fluidized bed unit is communicated with a discharge port of the particle storage tank unit; a feeding hole of the particle storage tank unit is communicated with a discharging hole of the fluidized bed unit; an inlet of the gas-solid separator unit is communicated with an outlet of the fluidized bed unit; and a bottom outlet of the gas-solid separator unit is communicated with an inlet of the particle storage tank unit. The problems that in the prior art, liquid-phase cold storage is poor in safety, a fixed solid-phase cold storage thermocline and an indirect fluidized bed are high in thermal resistance, and the system is complex are solved, and the efficiency of a cold storage system and the operation stability of the system are improved.

Description

Technical Field

[0001] This utility model relates to the field of energy storage technology, specifically to a fluidized bed cold storage system based on direct heat exchange. Background Technology

[0002] Against the backdrop of global pursuit of sustainable development and addressing climate change, my country is actively promoting energy transition, with "dual carbon" targets becoming a crucial strategic direction. In this process, the development of new energy sources such as photovoltaics and wind power has attracted significant attention; however, the intermittency and volatility of these new energy sources pose numerous challenges to the power system. Liquid air energy storage, as a novel large-scale energy storage technology, boasts advantages such as high energy density, long lifespan, and environmental friendliness, and is gradually becoming one of the key technologies for solving these problems. The cold storage system plays a crucial role in liquid air energy storage, and its performance directly affects the efficiency and reliability of the entire energy storage system.

[0003] Cold storage systems require characteristics such as large cold capacity, high cold storage efficiency, stability during multiple cycles, and low cost. Currently, based on the cold storage materials used, cold storage technologies are divided into two types: sensible heat cold storage and fixed packed bed cold storage. Sensible heat cold storage utilizes the sensible heat properties of materials to store cold energy. In liquid air energy storage systems, dual-tank cold storage technology using liquids such as methanol and propane as cold storage materials has high heat transfer coefficients and cold storage efficiency, and the temperature is easy to control. However, methanol and propane are flammable, explosive, and volatile, resulting in high maintenance costs and limiting their large-scale application. Fixed packed bed cold storage, using solids such as rocks as cold storage materials, has good economic and chemical stability, but the internal thermocline effect is significant, leading to lower cold storage efficiency.

[0004] Meanwhile, Chinese patent CN119412987A discloses a novel cold storage system and method for liquid air energy storage based on fluidization technology. Its indirect fluidized bed relies on heat exchanger surface conduction, which has the disadvantages of high thermal resistance and complex system (requiring additional fans and pipelines). Utility Model Content

[0005] The technical problem to be solved by this utility model is to provide a fluidized bed cold storage system based on direct heat exchange, so as to solve the problems of poor safety of liquid phase cold storage, high thermal resistance of fixed solid phase cold storage inclined temperature layer and indirect fluidized bed and system complexity in the prior art, and improve the efficiency and operational stability of the cold storage system.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows.

[0007] The fluidized bed cold storage system based on direct heat exchange includes a fluidized bed unit, a particle storage tank unit, and a gas-solid separator unit, which form a closed loop through pipelines and realize direct contact between gas, solid, and liquid phases.

[0008] The feed inlet of the fluidized bed unit is connected to the discharge outlet of the particle storage tank unit;

[0009] The feed inlet of the granular storage tank unit is connected to the discharge outlet of the fluidized bed unit;

[0010] The inlet of the gas-solid separator unit is connected to the outlet of the fluidized bed unit;

[0011] The bottom outlet of the gas-solid separator unit is connected to the inlet of the particle storage tank unit.

[0012] Preferably, the fluidized bed unit includes:

[0013] Solid particles, wherein the solid particles are solid-phase cold storage materials that circulate between the fluidized bed unit, the particle storage tank unit and the gas-solid separator unit;

[0014] A fluidized bed, wherein the bottom inlet of the fluidized bed is connected to the outlet of the cryogenic pump of the liquid air energy storage system;

[0015] An ambient temperature particle collector is located at the top of the fluidized bed;

[0016] A cryogenic particle collector is located at the bottom of the fluidized bed;

[0017] Both the ambient temperature particle collector and the low temperature particle collector are at an angle of 30° to 45° to the vertical bed wall of the fluidized bed, and both are two-section annular structures consisting of an upper section and a lower section; the upper section is made of seamless material, and the lower section is a grid structure.

[0018] Preferably, the particle storage tank unit includes:

[0019] An ambient temperature granule storage tank, wherein the inlet of the ambient temperature granule storage tank is connected to the ambient temperature outlet at the top of the fluidized bed;

[0020] A cryogenic particle storage tank, wherein the inlet of the cryogenic particle storage tank is connected to the cryogenic outlet at the bottom of the fluidized bed; the pipe connecting the outlet of the cryogenic particle storage tank to the inlet of the fluidized bed is also connected to the compressor outlet of the liquid air energy storage system.

[0021] Both the ambient temperature particle storage tank and the cryogenic particle storage tank have a double-cone hopper structure with a cone angle of 60°~70°, and are equipped with vibrators to prevent particle bridging.

[0022] Preferably, the pellet storage tank unit further includes:

[0023] A room temperature particle collection control valve is installed on the pipeline between the inlet of the room temperature particle storage tank and the room temperature particle collector.

[0024] A cryogenic particle collection control valve is installed on the pipeline between the inlet of the cryogenic particle storage tank and the cryogenic particle collector.

[0025] A room temperature particle feeding control valve is installed on the pipeline between the outlet of the room temperature particle storage tank and the inlet of the fluidized bed.

[0026] A cryogenic particle feed control valve is installed on the pipeline between the outlet of the cryogenic particle storage tank and the inlet of the fluidized bed.

[0027] The pipes between the inlet of the ambient temperature particle storage tank and the ambient temperature particle collector, the pipes between the inlet of the cryogenic particle storage tank and the cryogenic particle collector, and the pipes between the outlet of the ambient temperature particle storage tank and the inlet of the fluidized bed all form an angle of 30° to 45° with the vertical wall of the fluidized bed.

[0028] Preferably, the gas-solid separator unit includes:

[0029] An ambient temperature gas-solid separator, wherein the inlet of the ambient temperature gas-solid separator is connected to the top ambient temperature outlet of the fluidized bed, the bottom outlet of the ambient temperature gas-solid separator is connected to the inlet of the ambient temperature particle storage tank, and the top outlet of the ambient temperature gas-solid separator is connected to the heater inlet of the liquid air energy storage system.

[0030] The cryogenic gas-solid separator has its inlet connected to the lower middle cryogenic outlet of the fluidized bed, its bottom outlet connected to the inlet of the cryogenic particle storage tank, and its top outlet connected to the inlet of the liquefaction heat exchanger of the liquid air energy storage system.

[0031] Preferably, the gas-solid separator unit further includes:

[0032] An ambient temperature separator inlet control valve is installed on the pipeline between the inlet of the ambient temperature gas-solid separator and the ambient temperature outlet of the fluidized bed.

[0033] A cryogenic separator inlet control valve is installed on the pipeline between the inlet of the cryogenic gas-solid separator and the cryogenic outlet of the fluidized bed.

[0034] Ambient temperature return material control valve, wherein the ambient temperature return material control valve is installed on the pipeline between the bottom outlet of the ambient temperature gas-solid separator and the inlet of the ambient temperature particle storage tank;

[0035] A cryogenic return control valve is installed on the pipeline between the bottom outlet of the cryogenic gas-solid separator and the inlet of the cryogenic particle storage tank.

[0036] Due to the adoption of the above technical solutions, the technological progress achieved by this utility model is as follows.

[0037] This invention constructs a highly efficient and stable cold energy storage and release system through a fluidized bed design with direct gas-solid-liquid multiphase contact and strong convective heat transfer. Compared to traditional liquid-phase cold storage technology, using solid particles as the cold storage medium completely avoids the risks of flammability and explosion, significantly improving system safety and environmental adaptability. It overcomes the limitations of the inclined temperature layer in fixed packed beds, utilizing the intense mixing and collisions formed by particle fluidization within the fluidized bed to achieve strong convective heat transfer characteristics. This enables rapid transfer and uniform distribution of cold energy, significantly increasing the heat transfer contact area and disturbance intensity, and significantly improving cold energy transfer efficiency and cycle stability. Simultaneously, the direct heat exchange mode without intermediate heat exchange media simplifies the system structure, is compatible with various heat exchange fluids such as liquid air and ambient temperature air, and has significant advantages such as high safety, simple operation, high cold storage efficiency, stable cycle, and wide applicability. It provides a safe and efficient core solution for liquid air energy storage systems, which is conducive to the large-scale development of liquid air energy storage technology. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the structure of this utility model.

[0039] Among them: 10. Fluidized bed, 11. Solid particles, 12. Low-temperature particle collector, 13. Normal-temperature particle collector, 20. Normal-temperature particle storage tank, 21. Normal-temperature particle collection control valve, 22. Normal-temperature particle feed control valve, 23. Normal-temperature return control valve, 30. Normal-temperature gas-solid separator, 31. Normal-temperature separator inlet control valve, 40. Low-temperature particle storage tank, 41. Low-temperature particle collection control valve, 42. Low-temperature particle feed control valve, 43. Low-temperature return control valve, 50. Low-temperature gas-solid separator, 51. Low-temperature separator inlet control valve, 100. Low-temperature pump outlet liquid air, 200. Heater inlet air, 300. Compressor outlet air, 400. Liquefaction heat exchanger inlet air. Detailed Implementation

[0040] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0041] A fluidized bed cold storage system based on direct heat exchange, combined with Figure 1 As shown, the system includes a fluidized bed unit, a particle storage tank unit, and a gas-solid separator unit. The inlet of the fluidized bed unit is connected to the outlet of the particle storage tank unit; the inlet of the particle storage tank unit is connected to the outlet of the fluidized bed unit; the inlet of the gas-solid separator unit is connected to the outlet of the fluidized bed unit; and the bottom outlet of the gas-solid separator unit is connected to the inlet of the particle storage tank unit. The fluidized bed unit, particle storage tank unit, and gas-solid separator unit are connected by pipelines to form a closed loop, achieving strong convective heat transfer through direct contact between the gas, solid, and liquid phases.

[0042] The fluidized bed unit includes solid particles 11, a fluidized bed 10, an ambient temperature particle collector 13, and a low temperature particle collector 12.

[0043] Solid particles 11 circulate among the fluidized bed unit, particle storage tank unit, and gas-solid separator unit. These solid particles 11 serve as a solid-phase cold storage material, acting as an energy and cold storage medium to store or release cold energy. Materials such as pebbles, glass, basalt, concrete, granite, sodium chloride, dolomite, or encapsulated particles are used. The particle size of the solid particles 11 is one of the key parameters affecting the fluidization performance within the fluidized bed 10. Too small a particle size easily leads to particle agglomeration, increasing the separator load; too large a particle size requires a higher gas velocity, thus reducing heat transfer efficiency. The uniformity of particle size distribution affects bed stability, necessitating particle size optimization to balance fluidization energy consumption and heat transfer efficiency.

[0044] The fluidized bed 10 is used to fluidize, heat exchange, and collect solid particles 11 within the bed. The bottom inlet of the fluidized bed 10 is connected to the outlet of the cryogenic pump of the liquid air energy storage system, thereby inputting cryogenic pump outlet liquid air 100 into the fluidized bed 10.

[0045] The ambient temperature particle collector 13 is located at the top of the fluidized bed 10. The material of the ambient temperature particle collector 13 can be stainless steel, nickel-based alloy, or wear-resistant high-chromium cast iron, etc. The ambient temperature particle collector 13 is used to collect the solid particles 11 that have completed the cooling process. The cryogenic particle collector 12 is located in the lower cryogenic section of the fluidized bed 10. The cryogenic particle collector 12 needs to be made of materials resistant to low temperatures, abrasion, and corrosion, such as cryogenic alloys or stainless steel, etc. The cryogenic particle collector 12 is used to collect the solid particles 11 that have completed the cold storage process. Specifically, both the ambient temperature particle collector 13 and the cryogenic particle collector 12 form an angle of 30° to 45° with the vertical bed wall of the fluidized bed 10, and both are two-section annular structures consisting of an upper section and a lower section. The upper section is made of seamless material and is used to capture solid particles; the lower section is a grid structure, mainly used to separate fine particles and prevent blockage of the feed inlet pipe of the particle storage tank unit.

[0046] The particle storage tank unit includes an ambient temperature particle storage tank 20 and a cryogenic particle storage tank 40. The inlet at the top of the ambient temperature particle storage tank 20 is connected to the ambient temperature outlet at the top of the fluidized bed 10, which is also connected to the ambient temperature particle collector 13. The outlet at the bottom of the ambient temperature particle storage tank 20 is connected to the inlet at the bottom of the fluidized bed 10. The ambient temperature particle storage tank 20 is used to store solid particles 11 that have completed the cooling process. The inlet at the top of the cryogenic particle storage tank 40 is connected to the cryogenic outlet at the bottom of the fluidized bed 10, which is also connected to the cryogenic particle collector 12. The outlet at the bottom of the cryogenic particle storage tank 40 is connected to the inlet at the bottom of the fluidized bed 10. The cryogenic particle storage tank 40 is used to store the solid particles 11 that have completed the cold storage process. The pipe connecting the outlet of the cryogenic particle storage tank 40 to the inlet of the fluidized bed 10 is also connected to the compressor outlet of the liquid air energy storage system, thereby enabling the solid particles 11 in the cryogenic particle storage tank 40 to enter the fluidized bed 10 through the compressor outlet air 300. At the same time, both the ambient temperature particle storage tank 20 and the cryogenic particle storage tank 40 have a double-cone structure with a cone angle of 60°~70° and are equipped with vibrators to prevent particle bridging and improve the stability of receiving and unloading. Ambient temperature particle storage tank 20 is located outside the middle of fluidized bed 10, allowing solid particles 11 that have completed the cooling process within fluidized bed 10 to automatically flow into ambient temperature particle storage tank 20 by gravity. Simultaneously, solid particles 11 within ambient temperature particle storage tank 20 can also automatically flow into fluidized bed 10 by gravity, reducing energy consumption. Low temperature particle storage tank 40 is located below the fluidized bed 10, allowing solid particles 11 that have completed cooling within fluidized bed 10 to automatically flow into fluidized bed 10 by gravity. Solid particles 11 within low temperature particle storage tank 40 can be carried into fluidized bed 10 by compressor outlet air 300.

[0047] Specifically, the ambient temperature granular storage tank 20 is made of high-strength, wear-resistant, and corrosion-resistant materials. Its main body is made of stainless steel, nickel-based alloys, or wear-resistant high-chromium cast iron, which are oxidation-resistant, wear-resistant, and corrosion-resistant, ensuring long-term stable storage of ambient temperature granules. To reduce the impact of ambient heat on the temperature of the granules inside the tank, an insulation layer is installed on the outer side or wall of the ambient temperature granular storage tank 20, filled with insulation media such as fiberglass or polyurethane foam. Simultaneously, the ambient temperature granular storage tank 20 is equipped with a temperature monitoring device and a pressure balancing valve to monitor the internal pressure and temperature in real time, ensuring safe operation.

[0048] The cryogenic particle storage tank 40 is made of high-strength, wear-resistant, and low-temperature-resistant materials. Its main body is made of cryogenic stainless steel or cryogenic alloys to withstand extreme low-temperature environments. To maintain the internal cryogenic state, the outer surface or wall of the cryogenic particle storage tank 40 is wrapped or filled with high-efficiency insulation materials such as perlite or vacuum insulation panels to reduce heat loss. In addition, the cryogenic particle storage tank 40 is equipped with a pressure relief valve and a temperature sensor system, which can monitor changes in internal pressure and temperature in real time and automatically activate protective measures in case of abnormalities, ensuring the safe and stable operation of the storage tank under cryogenic conditions.

[0049] The pellet storage tank unit also includes an ambient temperature pellet collection control valve 21, a cryogenic pellet collection control valve 41, an ambient temperature pellet feed control valve 22, and a cryogenic pellet feed control valve 42. The ambient temperature pellet collection control valve 21 is installed on the pipeline between the inlet of the ambient temperature pellet storage tank 20 and the ambient temperature pellet collector 13, and is used to control the flow rate of the solid pellets 11 that have completed the cooling process. The cryogenic pellet collection control valve 41 is installed on the pipeline between the inlet of the cryogenic pellet storage tank 40 and the cryogenic pellet collector 12. The low-temperature particle collection control valve 41 is used to control the flow rate of solid particles 11 that complete the cold storage process; the ambient temperature particle feeding control valve 22 is installed on the pipeline between the outlet of the ambient temperature particle storage tank 20 and the inlet of the fluidized bed 10, and is used to control the flow rate of solid particles that carry out the cold storage process; the low-temperature particle feeding control valve 42 is installed on the pipeline between the outlet of the low-temperature particle storage tank 40 and the inlet of the fluidized bed 10, and is used to control the flow rate of solid particles that carry out the cold release process. Meanwhile, the pipes between the inlet of the ambient temperature particle storage tank 20 and the ambient temperature particle collector 13, the pipes between the inlet of the low temperature particle storage tank 40 and the low temperature particle collector 12, and the pipes between the outlet of the ambient temperature particle storage tank 20 and the inlet of the fluidized bed 10 are all at an angle of 30° to 45° to the vertical bed wall of the fluidized bed 10. In this way, the solid particles 11 can automatically flow into or out of the ambient temperature particle storage tank 20 and the low temperature particle storage tank 40 under the action of gravity.

[0050] The gas-solid separator unit includes an ambient temperature gas-solid separator 30 and a low temperature gas-solid separator 50. The ambient temperature gas-solid separator 30 is used to separate the gas and solid two-phase flow in the cold storage process. Specifically, the inlet of the ambient temperature gas-solid separator 30 is connected to the top ambient temperature outlet of the fluidized bed 10; the bottom outlet of the ambient temperature gas-solid separator 30 is connected to the inlet of the ambient temperature particle storage tank 20; and the top outlet of the ambient temperature gas-solid separator 30 is connected to the heater inlet of the liquid air energy storage system, thereby enabling the clean air separated at the top of the ambient temperature gas-solid separator 30 to be used as the heater inlet air 200 and transported to the heater inlet of the liquid air energy storage system through a pipeline. The cryogenic gas-solid separator 50 is used to separate the gas-solid two-phase flow during the cooling process. Specifically, the inlet of the cryogenic gas-solid separator 50 is connected to the lower-middle cryogenic outlet of the fluidized bed 10; the bottom outlet of the cryogenic gas-solid separator 50 is connected to the inlet of the cryogenic particle storage tank 40; and the top outlet of the cryogenic gas-solid separator 50 is connected to the inlet of the liquefied heat exchanger of the liquid air energy storage system. This allows the clean air separated at the top of the cryogenic gas-solid separator 50 to be used as the inlet air 400 of the liquefied heat exchanger and transported to the inlet of the liquefied heat exchanger of the liquid air energy storage system through a pipeline.

[0051] The main functions of the ambient temperature gas-solid separator 30 and the cryogenic gas-solid separator 50 are to separate solid particles from the gas-solid two-phase flow, achieving gas phase purification and solid particle 11 recycling. Both separators are designed to balance solid particle 11 separation efficiency with gas flow resistance. Typically, a cyclone separation structure combined with guide nozzles is used, and internal flow channels are optimized to reduce gas turbulence losses. Furthermore, a multi-stage series design further improves separation accuracy. Considering the ambient temperature characteristics of the gas phase during cold storage and the low temperature characteristics during cold release, as well as the wear caused by particle flow, the ambient temperature gas-solid separator 30 is made of high-strength, wear-resistant, and corrosion-resistant materials. Its main body material is selected from stainless steel, nickel-based alloys, or wear-resistant high-chromium cast iron, which are oxidation-resistant, wear-resistant, and corrosion-resistant. The cryogenic gas-solid separator 50 is made of high-strength, wear-resistant, and low-temperature-resistant materials. Its main body material is selected from low-temperature-resistant stainless steel or low-temperature-resistant alloys to withstand extreme low-temperature environments.

[0052] To reduce the impact of ambient heat on the particle temperature within the ambient temperature fluidized bed and the ambient temperature gas-solid separator 30, an insulation layer is installed on the outer side or wall of the ambient temperature gas-solid separator 30 and the ambient temperature fluidized bed, filled with insulation media such as glass fiber and polyurethane foam. To maintain the low-temperature state within the low-temperature fluidized bed and the low-temperature gas-solid separator 50, the outer side or wall of the low-temperature gas-solid separator 50 and the low-temperature fluidized bed are wrapped or filled with high-efficiency insulation materials such as perlite and vacuum insulation panels. All low-temperature equipment is placed in a low-temperature cold box to reduce cooling loss. Simultaneously, all equipment is equipped with temperature and pressure monitoring devices, which can monitor the pressure and temperature within the equipment in real time and automatically activate protective measures in case of abnormalities to ensure safe system operation.

[0053] The gas-solid separator unit also includes an ambient temperature separator inlet control valve 31, a cryogenic separator inlet control valve 51, an ambient temperature return material control valve 23, and a cryogenic return material control valve 43. The ambient temperature separator inlet control valve 31 is located on the pipeline between the inlet of the ambient temperature gas-solid separator 30 and the ambient temperature outlet of the fluidized bed 10, and is used to control the flow rate for gas-solid two-phase flow separation during the cold storage process. The cryogenic separator inlet control valve 51 is located on the pipeline between the inlet of the cryogenic gas-solid separator 50 and the cryogenic outlet of the fluidized bed 10. The inlet control valve 51 is used to control the flow rate of the gas-solid two-phase flow after the cold release process is completed; the ambient temperature return control valve 23 is installed on the pipeline between the bottom outlet of the ambient temperature gas-solid separator 30 and the inlet of the ambient temperature particle storage tank 20, and the ambient temperature return control valve 23 is used to control the circulation flow rate of the solid particles after the gas-solid separation of the cold storage process is completed; the low temperature return control valve 43 is installed on the pipeline between the bottom outlet of the low temperature gas-solid separator 50 and the inlet of the low temperature particle storage tank 40, and the low temperature return control valve 43 is used to control the circulation flow rate of the solid particles after the gas-solid separation of the cold release process is completed.

[0054] In this system, the ambient temperature particle collection control valve 21, the low temperature particle feed control valve 42, the low temperature return control valve 43, and the low temperature separator inlet control valve 51 are linked, as are the ambient temperature particle feed control valve 22, the low temperature particle collection control valve 41, the ambient temperature return control valve 23, and the ambient temperature separator inlet control valve 31. That is, during the cooling process, the ambient temperature particle collection control valve 21, the low temperature particle feed control valve 42, the low temperature return control valve 43, and the low temperature separator inlet control valve 51 are opened, and the ambient temperature particle feed control valve 22, the low temperature particle collection control valve 41, the ambient temperature return control valve 23, and the ambient temperature separator inlet control valve 31 are closed; during the cold storage process, the ambient temperature particle feed control valve 22, the low temperature particle collection control valve 41, the ambient temperature return control valve 23, and the ambient temperature separator inlet control valve 31 are opened, and the ambient temperature particle collection control valve 21, the low temperature particle feed control valve 42, the low temperature return control valve 43, and the low temperature separator inlet control valve 51 are closed. Furthermore, the control valves mentioned above and the control valves on the subsequent gas-solid separator are preferably gate valves.

[0055] In this system, the airflow velocity within the fluidized bed 10 is one of the key parameters for the formation of fluidized state of the solid particles 11 within the bed. During the cold storage process, the airflow within the bed originates from the cryogenic pump outlet liquid air 100 of the cryogenic pump outlet of the liquid air energy storage system. This cryogenic pump outlet liquid air 100 directly contacts the solid particles 11 at the bottom of the bed and exchanges heat. The vaporized gas formed by vaporization serves as the fluidizing medium to drive the fluidization of the particles. During the cold release process, the airflow within the bed originates from the compressor outlet air 300 of the compressor outlet of the liquid air energy storage system. By coordinating and controlling the airflow velocity and the flow rate of the solid particles 11, the heat exchange efficiency and heat exchange rate between the heat exchange fluid and the solid particles 11 can be effectively controlled. Meanwhile, by using solid particles 11 as the energy storage and cold storage medium, the risks of flammability, explosiveness, and volatility of traditional liquid-phase cold storage materials are avoided, resulting in high safety and strong environmental adaptability. Furthermore, the type and size of the solid particles 11 can be flexibly adjusted according to the cold storage capacity requirements. Through the fluidized bed strong convection heat transfer design with direct contact between gas, solid, and liquid phases, the limitations of fixed packed bed inclined temperature layer are overcome. The intense mixing and collision formed by particle fluidization significantly increases the heat transfer contact area and disturbance intensity, thereby significantly improving the cold energy transfer efficiency and cycle stability. The direct heat exchange mode without intermediate heat exchange medium simplifies the system structure, is compatible with various heat exchange fluids such as liquid air and room temperature air, and has a wide range of applications. Moreover, through the closed-loop circulation of each unit and precise control valve regulation, efficient cold storage and release switching is achieved, which has significant advantages such as high safety, simple operation, high cold storage efficiency, stable cycle, and wide applicability.

[0056] The working principle of this system is as follows:

[0057] (1) In cold storage mode: Close the ambient temperature particle collection control valve 21, the low temperature particle feed control valve 42, the low temperature return control valve 43 and the low temperature separator inlet control valve 51. First, open the ambient temperature particle feed control valve 22 to let a small amount of ambient temperature solid particles 11 flow into the fluidized bed 10. The liquid air 100 at the outlet of the low temperature pump is pressurized by the low temperature pump and enters the fluidized bed 10 through the outlet pipe of the low temperature pump to undergo a violent vaporization phenomenon with the ambient temperature solid particles 11. By detecting the change in pressure in the fluidized bed, open the ambient temperature particle collection control valve 22 in a timely manner. The inlet control valve 31 of the cryogenic separator and the ambient temperature return control valve 23 gradually increase the flow rates of liquid air and ambient temperature solid particles. Once the ambient temperature separator 30 and the ambient temperature particle storage tank 20 are operating normally, the gas-solid-liquid circulation is established. The heater inlet air 200, which meets the system requirements, enters the liquid air energy storage system. The separated ambient temperature solid particles are recycled after entering the ambient temperature particle storage tank 20. The liquid air 100 at the outlet of the cryogenic pump continuously evaporates and vaporizes at the bottom of the fluidized bed 10, meeting the needs of fluidized bed vaporization and heat exchange. By monitoring the particle temperature at the bottom of the fluidized bed 10, when the particle temperature drops at a rate less than 0.1℃ / min, the cryogenic particle collection control valve 41 is opened to complete the cold storage process of the solid particles.

[0058] (2) Cooling mode: Close the ambient temperature particle feed control valve 22, the low temperature particle collection control valve 41, the ambient temperature return control valve 23, and the ambient temperature separator inlet control valve 31. First, open the low temperature particle feed control valve 42. The compressor outlet air 300 carries the low temperature particles to the fluidized bed for fluidization and heat exchange. By detecting the pressure change in the fluidized bed, open the low temperature separator inlet control valve 51 and the low temperature return control valve 43 in a timely manner to gradually increase the flow rate of ambient temperature air and low temperature solid particles. When the low temperature separator 50 and the low temperature particle storage tank 40 are running normally, the gas-solid cycle has been established. The liquefied heat exchanger inlet air 400 that meets the system requirements enters the liquid air energy storage system. The separated low temperature solid particles enter the low temperature particle storage tank 40 and are recycled. The air and solid particles are controlled in tandem to meet the needs of fluidized bed gasification and heat exchange. By monitoring the particle temperature at the top of the fluidized bed 10, when the particle temperature rise rate is less than 0.1℃ / min, open the ambient temperature particle collection control valve 41 to collect the solid particles that have completed the cooling process.

Claims

1. A fluidized bed cold storage system based on direct heat exchange, characterized in that: This includes fluidized bed units, particle storage tank units, and gas-solid separator units that form a closed loop through pipelines and achieve direct contact between gas, solid, and liquid phases through strong convective heat transfer. The feed inlet of the fluidized bed unit is connected to the discharge outlet of the particle storage tank unit; The feed inlet of the granular storage tank unit is connected to the discharge outlet of the fluidized bed unit; The inlet of the gas-solid separator unit is connected to the outlet of the fluidized bed unit; The bottom outlet of the gas-solid separator unit is connected to the inlet of the particle storage tank unit.

2. The fluidized bed cold storage system based on direct heat exchange according to claim 1, characterized in that: The fluidized bed unit includes: Solid particles (11), wherein the solid particles (11) are solid-phase cold storage materials that circulate between the fluidized bed unit, the particle storage tank unit and the gas-solid separator unit; Fluidized bed (10), the bottom inlet of which is connected to the outlet of the cryogenic pump of the liquid air energy storage system; A room temperature particle collector (13) is located above the fluidized bed (10); A low-temperature particle collector (12) is located at the bottom of the fluidized bed (10); Both the ambient temperature particle collector (13) and the low temperature particle collector (12) are at an angle of 30° to 45° to the vertical bed wall of the fluidized bed (10), and both are two-section annular structures including an upper half and a lower half; the upper half is made of seamless material and the lower half is a grid structure.

3. The fluidized bed cold storage system based on direct heat exchange according to claim 2, characterized in that: The particle storage tank unit includes: Ambient temperature particle storage tank (20), wherein the inlet of the ambient temperature particle storage tank (20) is connected to the ambient temperature outlet at the top of the fluidized bed (10); The low-temperature particle storage tank (40) has its inlet connected to the low-temperature outlet at the bottom of the fluidized bed (10); the pipe connecting the outlet of the low-temperature particle storage tank (40) to the inlet of the fluidized bed (10) is also connected to the compressor outlet of the liquid air energy storage system. Both the ambient temperature particle storage tank (20) and the low temperature particle storage tank (40) have a double cone structure with a cone angle of 60°~70°, and are equipped with vibrators to prevent particle bridging.

4. The fluidized bed cold storage system based on direct heat exchange according to claim 3, characterized in that: The pellet storage tank unit also includes: A room temperature particle collection control valve (21) is installed on the pipeline between the inlet of the room temperature particle storage tank (20) and the room temperature particle collector (13); The low-temperature particle collection control valve (41) is installed on the pipeline between the inlet of the low-temperature particle storage tank (40) and the low-temperature particle collector (12). Ambient temperature particle feeding control valve (22) is installed on the pipeline between the outlet of the ambient temperature particle storage tank (20) and the inlet of the fluidized bed (10); Low-temperature particle feeding control valve (42) is installed on the pipeline between the outlet of the low-temperature particle storage tank (40) and the inlet of the fluidized bed (10); The pipes between the inlet of the ambient temperature particle storage tank (20) and the ambient temperature particle collector (13), the pipes between the inlet of the low temperature particle storage tank (40) and the low temperature particle collector (12), and the pipes between the outlet of the ambient temperature particle storage tank (20) and the inlet of the fluidized bed (10) all form an angle of 30° to 45° with the vertical bed wall of the fluidized bed (10).

5. The fluidized bed cold storage system based on direct heat exchange according to claim 3, characterized in that: The gas-solid separator unit includes: Ambient temperature gas-solid separator (30), the inlet of the ambient temperature gas-solid separator (30) is connected to the top ambient temperature outlet of the fluidized bed (10), the bottom outlet of the ambient temperature gas-solid separator (30) is connected to the inlet of the ambient temperature particle storage tank (20), and the top outlet of the ambient temperature gas-solid separator (30) is connected to the heater inlet of the liquid air energy storage system. The low-temperature gas-solid separator (50) has its inlet connected to the low-temperature outlet of the middle and lower part of the fluidized bed (10), its bottom outlet connected to the inlet of the low-temperature particle storage tank (40), and its top outlet connected to the inlet of the liquefaction heat exchanger of the liquid air energy storage system.

6. The fluidized bed cold storage system based on direct heat exchange according to claim 5, characterized in that: The gas-solid separator unit also includes: Ambient temperature separator inlet control valve (31) is provided on the pipeline between the inlet of the ambient temperature gas-solid separator (30) and the ambient temperature outlet of the fluidized bed (10). The cryogenic separator inlet control valve (51) is installed on the pipeline between the inlet of the cryogenic gas-solid separator (50) and the cryogenic outlet of the fluidized bed (10). Ambient temperature return material control valve (23) is installed on the pipeline between the bottom outlet of the ambient temperature gas-solid separator (30) and the inlet of the ambient temperature particle storage tank (20); The cryogenic return control valve (43) is located on the pipeline between the bottom outlet of the cryogenic gas-solid separator (50) and the inlet of the cryogenic particle storage tank (40).

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