A heterogeneous particle partition relay asymmetric moving bed cold storage system and its operation method

Abstract

This invention discloses a heterogeneous particle partitioned relay asymmetric moving bed cold storage system and its operation method. The system includes a first moving bed heat exchanger, a cold particle storage tank, a second moving bed heat exchanger, a first / second hot particle storage tank, and a conveying device. The first moving bed heat exchanger, the cold particle storage tank, and the second moving bed heat exchanger are connected in series vertically, forming a gravity-driven trajectory path for the particles from top to bottom. The conveying device connects the second hot particle storage tank and the first hot particle storage tank, forming a mechanical return path for the particles from bottom to top. During operation, the particles in the cryogenic region rely solely on gravity to complete heat exchange, achieving dual decoupling of particle state transition and mechanical transport in both physical space and operating time. This architecture, while removing the mechanical drive components in the cryogenic region, utilizes the cold particle storage tank as an intermediate hub to achieve asynchronous scheduling and efficient management of charging and discharging cold conditions, significantly reducing cryogenic heat leakage losses and improving the system's engineering reliability and grid dispatch adaptability.

Description

Technical Field

[0001] This invention belongs to the field of energy storage and heat exchange technology, specifically relating to a heterogeneous particle partition relay asymmetric moving bed cold storage system and its operation method. Background Technology

[0002] Cold storage technology is key to achieving efficient energy conversion and is mainly divided into two categories: fixed bed and moving bed. Although fixed beds have a simple structure, they suffer from problems such as low utilization of heat exchange medium, large axial temperature difference, and severe degradation of the thermocline in ultra-low temperature environments, making them difficult to meet the needs of large-scale energy storage.

[0003] To overcome the inherent drawbacks of fixed beds in cold storage applications, such as low energy utilization and large axial temperature difference, moving bed solutions have become a research hotspot in recent years. Theoretical studies have shown that continuous particle renewal can maintain a highly efficient gas-solid heat exchange interface, and the thermodynamic efficiency can be optimized by utilizing a vertical series structure.

[0004] However, the design of existing moving bed cold storage technology has long been limited by a "steady-state continuous circulation" paradigm. In order to achieve the "continuous particle renewal" pursued in theory, existing schemes generally assume that the cold storage particles must maintain a synchronous, closed-loop mechanical reciprocating circulation between cold and hot temperature zones. Specifically, this usually relies heavily on mechanical transmission devices such as bucket elevators and conveyor belts to forcibly return the particles to each temperature zone.

[0005] This over-reliance on the "continuous mechanical cycle" path, when applied to the extreme cryogenic conditions of liquid air energy storage (LAES) at approximately -170°C, creates a profound contradiction with the objective physical laws of the environment, exposing the following difficult-to-reconcile technical problems:

[0006] (1) Bottleneck of mechanical transmission in extremely low temperature environment: At about -170℃, conventional metal materials will suffer severe cold brittle fracture. At the same time, the moisture in the air is very easy to sublimate into ice, which leads to serious jamming and structural failure risks of the moving bearings and drive mechanisms of mechanical transmission components such as bucket elevators and conveyor belts. This "physical infeasibility of mechanical drive" directly challenges the foundation of continuous cycle design.

[0007] (2) Cooling loss in static and dynamic heat exchange processes: Continuous circulation systems inevitably need to cross the cryogenic (-170℃) and normal temperature regions, making it extremely difficult to provide long-term and effective dynamic thermal insulation for moving parts. The resulting huge cooling loss (cooling leakage) problem seriously reduces the overall cooling storage efficiency of the LAES system.

[0008] (3) Insufficient adaptability to asynchronous scheduling conditions: The charging (liquefaction) and releasing (power generation) conditions on the grid side are usually asynchronous in time. However, the continuous circulation mode of the existing moving bed requires that the heat exchange and mechanical transport processes must be carried out synchronously. Under intermittent scheduling conditions, if forced linkage is required, frequent mechanical start-stop will not only bring huge parasitic energy consumption, but may also cause fluctuations in heat exchange stability, which runs counter to the energy storage system's need for flexible scheduling.

[0009] In summary, while existing moving bed cold storage technology theoretically achieves particle renewal to enhance heat transfer, its inherent reliance on "continuous mechanical circulation" fails to fundamentally address issues related to engineering reliability, energy efficiency, and adaptability to asynchronous dispatching of modern power grids in extreme low-temperature environments. Therefore, there is an urgent need in this field for a cold storage system capable of physically partitioning particle temperatures, removing mechanical transmission in extremely low-temperature regions, and logically decoupling heat exchange and transport operations. Summary of the Invention

[0010] The purpose of this invention is to solve the technical problems of low engineering reliability, limited energy utilization, and rigidity in discontinuous operation of existing cryogenic moving bed cold storage systems. To this end, this invention provides a heterogeneous particle zoned relay asymmetric moving bed cold storage system and its operation method. By constructing a particle temperature-state physical zone and an asymmetric drive closed loop, mechanical conveying components within the cryogenic region are removed, eliminating the risk of brittle fracture and ice jamming of the transmission mechanism under extremely low temperature conditions. Furthermore, the particle storage nodes achieve time decoupling between heat exchange and conveying operations, thereby reducing parasitic heat loss in the cryogenic system and improving the system's adaptability to asynchronous grid-side charging and discharging scheduling.

[0011] To achieve the above objectives, the present invention adopts the following technical solution: a heterothermal particle partition relay asymmetric moving bed cold storage system, comprising a first hot particle storage tank, a first moving bed heat exchanger, a cold particle storage tank, a second moving bed heat exchanger, a second hot particle storage tank, and a conveying device, wherein the first moving bed heat exchanger, the cold particle storage tank, and the second moving bed heat exchanger are arranged in series in the vertical direction to form a gravity descent path for heterothermal particles from top to bottom;

[0012] The inlet end of the conveying device is connected to the outlet end of the second hot particle storage tank, and the outlet end of the conveying device is connected to the inlet end of the first hot particle storage tank, forming a mechanical return path for room temperature / hot particles from bottom to top.

[0013] The system has asymmetric drive closed-loop characteristics: the state transfer process of particles between the first moving bed heat exchanger, the cold particle storage tank and the second moving bed heat exchanger is driven by gravity.

[0014] The conveying device is configured to receive particles at the second hot particle storage tank and return the particles to the first hot particle storage tank.

[0015] Preferably, the first moving bed heat exchanger and the second moving bed heat exchanger are respectively provided with a first diffuser and a second diffuser at their gas inlets to guide the gas to pass through the bed uniformly.

[0016] Preferably, a first gas-solid separator and a second gas-solid separator are respectively provided at the gas outlet of the first moving bed heat exchanger and the second moving bed heat exchanger to separate particles and gases in the heat exchange gas flow.

[0017] Preferably, the gas pipelines of the first moving bed heat exchanger and the second moving bed heat exchanger are respectively provided with openable and closable valves for independently controlling the on / off state of the first moving bed heat exchanger and the second moving bed heat exchanger.

[0018] Preferably, the cold particle storage tank is located between the first moving bed heat exchanger and the second moving bed heat exchanger, and is used to receive ultra-low temperature particles from the first moving bed heat exchanger. The bottom of the cold particle storage tank is provided with a controlled discharge port for controlling the discharge, which serves as an intermediate buffer hub for ultra-low temperature particles when switching between charging and releasing modes.

[0019] The present invention also provides a method for operating an asymmetric moving bed cold storage system according to any one of the preceding claims, comprising the following steps:

[0020] Cooling mode: The particles to be cooled enter the first moving bed heat exchanger and come into countercurrent contact with the extremely low temperature gas. The cooled particles enter the cold particle storage tank for static storage under the action of gravity.

[0021] Cooling mode: The cold particles in the cold particle storage tank are supplied to the second moving bed heat exchanger as needed and come into countercurrent contact with the hot air flow. The heated particles enter the second hot particle storage tank.

[0022] Return mode: The conveying device is activated to return the particles in the second hot particle storage tank to the first hot particle storage tank. The return mode can operate independently of the charging mode and the releasing mode, or can be executed in parallel and synchronously with any of the charging mode and the releasing mode.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. By constructing an "asymmetric driven closed-loop" architecture, the system relies entirely on gravity to drive particle flow at approximately -170°C, thereby avoiding the risk of brittle fracture of metal materials in the cryogenic region and the possibility of failure of moving parts due to sublimation into ice, significantly improving the service life of the equipment and the stability of the system. Under gravity drive, the continuous renewal of particles maintains an efficient gas-solid heat exchange interface and reduces the axial temperature gradient of the bed, improving the heat exchange capacity for the same volume.

[0025] 2. By introducing a “zonal relay” architecture, the present invention uses a cold particle storage tank as an intermediate buffer node to separate the physical displacement of particles from the gas-solid heat exchange process in time and space. The conveying device operates only in the normal / hot temperature range, avoiding the complexity of deep cryogenic insulation of moving parts, thereby reducing heat leakage caused by mechanical equipment passing through low temperature regions and improving the efficiency of cold energy utilization.

[0026] 3. When performing charging or releasing heat exchange, the system only controls the gas path state; the return operation of room temperature / hot particles is carried out independently during the system standby interval according to external scheduling instructions, so that the system is no longer limited by the synchronization of mechanical transmission cycle, and can flexibly adapt to the time mismatch of grid-side charging and discharging, thus enhancing the operating condition adaptability of the energy storage system. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of a heterogeneous particle partitioning relay asymmetric moving bed cold storage system according to the present invention;

[0028] Figure 2 This is a graph showing the changes in gas temperature and particle temperature along the bed position; the horizontal axis represents the dimensionless position of the bed, and the vertical axis represents the temperature; the blue curve represents the change in gas temperature, and the red curve represents the change in particle temperature.

[0029] Figure 3 This is a comparison chart of the heat transfer performance of a fixed bed and a moving bed; the horizontal axis represents the apparent velocity of the fluid, and the vertical axis represents the heat transfer coefficient; the solid line represents the heat transfer coefficient variation curve of the fixed bed, and the dashed line represents the heat transfer coefficient variation curve of the moving bed.

[0030] In the diagram: 01 is the liquid air evaporator, 02 is the first hot particle storage tank, 03 is the first gas-solid separator, 04 is the first moving bed heat exchanger, 05 is the first diffuser, 06 is the cold particle storage tank, 07 is the second gas-solid separator, 08 is the second moving bed heat exchanger, 09 is the second diffuser, 10 is the second hot particle storage tank, 11 is the liquefaction main heat exchanger, and 12 is the conveying device. Detailed Implementation

[0031] This invention provides a specific hardware structure and operating logic for an asymmetric moving bed cryogenic storage system with zoned relay for heterogeneous particle storage. The system adopts a "zoned relay" and "asymmetric" layout, including a gas-solid heat exchange module installed in an extremely low temperature environment (approximately -170°C), and a group of particle storage tanks (including cold particle storage tanks and hot particle storage tanks) that serve as thermal buffers and connectors. Simultaneously, the system also includes an independent mechanical conveying module installed in a normal temperature or hot environment for conveying normal temperature / hot particles. In terms of operation, this system separates the heat exchange cycle of particles from the mechanical return process in both time and space: when the system performs the heat exchange steps of charging or releasing heat, the particles rely on gravity to flow downwards within the cryogenic gas-solid heat exchange module, completing efficient gas-solid heat exchange with the working fluid (such as gas). During this process, the mechanical transport module remains inactive. However, during gaps allowed by external power grid scheduling, system standby, or according to process requirements, the ambient temperature mechanical transport module is activated to transport the particles from a designated location (such as a hot particle storage tank) to the inlet of the heat exchange module or other storage locations to complete a complete particle cycle. Through this structural design and operational mode, this embodiment achieves decoupling of the airflow heat exchange process and the mechanical particle transport process in both physical space and time dimensions, thus providing a concrete hardware implementation solution for solving engineering challenges such as mechanical jamming, parasitic heat leakage, and adaptation to discontinuous power grid scheduling in cryogenic environments.

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be understood that the following embodiments are for illustrative purposes only and are not intended to limit the scope of protection of this invention.

[0033] Example 1

[0034] This embodiment provides a temperature-dependent particle partitioning relay asymmetric moving bed cold storage system. The system includes a liquid air evaporator 01, a first hot particle storage tank 02, a first gas-solid separator 03, a first moving bed heat exchanger 04, a first diffuser 05, a cold particle storage tank 06, a second gas-solid separator 07, a second moving bed heat exchanger 08, a second diffuser 09, a second hot particle storage tank 10, a liquefaction main heat exchanger 11, and a conveying device 12. The specific connection structure between each component is as follows:

[0035] The first moving bed heat exchanger 04, the cold particle storage tank 06, and the second moving bed heat exchanger 08 are arranged vertically in sequence to form a zoned relay path for particles with different temperatures. The cold particle storage tank 06 is located between the two moving bed heat exchange units and serves as a storage unit for intermediate cold particles and a zoned transition node.

[0036] The first moving bed heat exchanger 04 has a gas inlet at its lower part and is connected to the liquid air evaporator 01. A first diffuser 05 is also provided at the gas inlet of the first moving bed heat exchanger 04 to improve the uniformity of gas distribution entering the corresponding moving bed heat exchanger, allowing the gas and particles to form counter-current contact heat exchange within the bed. The gas outlet of the first moving bed heat exchanger 04 is connected to the first gas-solid separator 03. The particle inlet end of the first moving bed heat exchanger 04 is connected to the particle outlet end of the first hot particle storage tank 02, and the particle outlet end of the first moving bed heat exchanger 04 is connected to the inlet end of the cold particle storage tank 06. The cold particle storage tank 06 is located in the first... Above the second moving bed heat exchanger 08, a controlled discharge port is provided at its bottom. The controlled discharge port is connected to the particle inlet end of the second moving bed heat exchanger 08 to form a natural gravity discharge channel. The particle outlet end of the second moving bed heat exchanger 08 is connected to the inlet end of the second hot particle storage tank 10. The outlet end of the second hot particle storage tank 10 is connected to the inlet end of the conveying device 12. The outlet end of the conveying device 12 is connected to the first hot particle storage tank 02. The second hot particle storage tank 10 and the conveying device 12 form an external return path for ambient / hot particles, so that the ambient / hot particle return path is different from the cold particle storage path.

[0037] The second moving bed heat exchanger 08 is also provided with a gas inlet at the bottom and is connected to the liquefaction main heat exchanger 11. The gas inlet of the second moving bed heat exchanger 08 is also provided with a second diffuser 09, which is used to improve the uniformity of gas distribution entering the corresponding moving bed heat exchanger, so that the gas and particles form countercurrent contact heat exchange in the bed.

[0038] In this embodiment, a first gas-solid separator 03 and a second gas-solid separator 07 are respectively provided at the gas outlet of the first moving bed heat exchanger 04 and the second moving bed heat exchanger 08, which are used to realize the gas-solid separation of gas and particles after heat exchange and prevent particles from entering subsequent equipment with the airflow.

[0039] In addition, the gas pipelines of the first moving bed heat exchanger 04 and the second moving bed heat exchanger 08 are respectively equipped with openable and closable valves, which are used to independently control the on / off state of the first moving bed heat exchanger 04 and the second moving bed heat exchanger 08.

[0040] In this embodiment, the system is equipped with a central control unit, which monitors the operating conditions of each functional unit in real time through temperature sensors and material level sensors installed at the first moving bed heat exchanger 04, the cold particle storage tank 06 and the second moving bed heat exchanger 08.

[0041] In addition, this system also includes an auxiliary power system and a measurement and control system: the gas path system is equipped with a gas drive device (such as a fan or compressor) to drive the gas to flow in the heat exchanger; each gas path pipeline is equipped with an electromagnetic control valve to switch the airflow direction; each storage tank and the particle outlet of the heat exchanger is equipped with a controlled feed valve (such as a rotary feed valve) to control the particle flow rate; the system is uniformly scheduled by the central control unit, which automatically opens and closes the gas path drive device and the particle feed valve by monitoring the temperature and material level signals of each unit in real time, so as to realize the logical switching of the system operating conditions.

[0042] Example 2

[0043] This embodiment provides an operation method for a heterogeneous particle zoned relay asymmetric moving bed cold storage system, as detailed below:

[0044] 2.1 Cooling Mode

[0045] (1) When the system starts the cooling mode, the hot particles in the first hot particle storage tank 02 enter the first moving bed heat exchanger 04; the liquid air evaporator 01 provides extremely low temperature gas (about -170°C) directly into the first diffuser 05. After the extremely low temperature gas is evenly distributed through the first diffuser 05, it passes through the particle bed of the first moving bed heat exchanger 04 from bottom to top and has countercurrent contact heat exchange with the particles to be cooled moving from top to bottom.

[0046] (2) The gas after heat exchange may carry a small amount of dust. It enters the first gas-solid separator 03 located at the top of the first moving bed heat exchanger 04 for fine filtration to achieve gas-solid separation and ensure that the output gas is clean before flowing to the subsequent process.

[0047] (3) After heat exchange, the particle temperature drops to an extremely low temperature (about -170°C) and is discharged from the bottom outlet of the first moving bed heat exchanger 04 under the action of gravity, and is stored in the cold particle storage tank 06.

[0048] At this time, the gas path of the second moving bed heat exchanger 08 remains closed, and the particles (which may be pre-stored room temperature particles) remain stationary or in standby mode.

[0049] During the cooling phase, the system refreshes the heat exchange interface through the flow of particles within the first moving bed 04. The gas and particles undergo efficient direct countercurrent heat exchange, achieving rapid cooling of the particles. Particles at extremely low temperatures fall directly into the cold particle storage tank 06 under their own gravity, avoiding the use of mechanical equipment for transportation. This eliminates engineering challenges caused by mechanical component brittleness, freezing, sealing failure, and dynamic heat leakage under extremely cold conditions. The cold particle storage tank 06, as an independent storage unit, statically stores the extremely low-temperature particles, providing a cold source for the subsequent cooling release phase and achieving temporary energy storage over time.

[0050] 2.2 Cooling Mode

[0051] (1) When the system starts the cooling mode, the discharge control valve at the bottom of the cold particle storage tank 06 is opened in a controlled manner, and the ultra-low temperature particles fall into the second moving bed heat exchanger 08 by gravity; the gas to be liquefied in the system process enters the second diffuser 09 at the bottom of the second moving bed heat exchanger 08. After the gas is evenly distributed by the second diffuser 09, it passes through the particle bed of the second moving bed heat exchanger 08 from bottom to top and has countercurrent contact heat exchange with the ultra-low temperature particles moving from top to bottom.

[0052] (2) After heat exchange, the gas is filtered and dust removed by the second gas-solid separator 07 located at the top of the second moving bed heat exchanger 08, and then enters the liquefaction main heat exchanger 11 for the reliquefaction process of liquid air.

[0053] (3) After absorbing heat, the particles are heated to room temperature or become hot particles, and are discharged from the bottom of the second moving bed heat exchanger 08 and enter the second hot particle storage tank 10.

[0054] At this time, the gas path of the first moving bed heat exchanger 04 remains closed. The cold particle storage tank 06, as the storage unit for ultra-low temperature particles, replenishes ultra-low temperature particles to the second moving bed heat exchanger 08 as needed during the cooling process, based on the bed level of the second moving bed heat exchanger 08, in order to maintain a stable heat exchange state within the second moving bed heat exchanger 08.

[0055] (4) When the controller detects that the material level of the second hot particle storage tank 10 reaches the preset threshold, the conveying device 12 is started to transport these normal temperature / hot particles from the second hot particle storage tank 10 back to the first hot particle storage tank 02 at the top of the system to complete one operating cycle.

[0056] The return operation of the conveying device 12 is physically independent of the heat exchanger's gas path system. Its operation can be carried out independently during system standby intervals, or, according to the energy management strategy, it can be executed in parallel and synchronously with any of the operating conditions in the charging and releasing modes, provided that the stability of the heat exchange gas flow is not disturbed. This independent or parallel operation capability ensures that the mechanical conveying and heat exchange conditions do not affect each other in actual operation, achieving complete time decoupling.

[0057] In the cold release mode, the particles in the cold particle storage tank 06 of this system fall to the second moving bed 08, and gravity is used again to transfer the particles from the storage state to the heat exchange unit, avoiding the mechanical transport of the extremely cold particles. In the second moving bed 08, the gas and the gradually descending extremely low temperature particles have countercurrent contact heat exchange. The particles absorb heat and rise in temperature, while the gas is cooled (or converted to a lower temperature), realizing the release of cold energy. The conveying device 12 only needs to transport the particles that have been heated to room temperature or hot state, without the need for extremely low temperature protection, which greatly reduces mechanical loss and heat preservation difficulty. Room temperature / hot particles are sent back from the second hot particle storage tank 10 below to the first hot particle storage tank 02 above via the conveying device 12, forming an asymmetric loop with the gravity falling path of the cold particles, ensuring independent and efficient circulation of particles at different temperatures.

[0058] In this application, "thermal particles" refers to particles in a normal or high-temperature state relative to an extremely low-temperature state.

[0059] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. All equivalent substitutions, improvements, and modifications made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A heterogeneous particle partitioned relay asymmetric moving bed cold storage system, characterized in that, It includes a first hot particle storage tank (02), a first moving bed heat exchanger (04), a cold particle storage tank (06), a second moving bed heat exchanger (08), a second hot particle storage tank (10), and a conveying device (12). The first moving bed heat exchanger (04), the cold particle storage tank (06), and the second moving bed heat exchanger (08) are arranged in series in the vertical height direction to form a gravity descent path for the particles with different temperatures from top to bottom. The inlet end of the conveying device (12) is connected to the outlet end of the second hot particle storage tank (10), and the outlet end of the conveying device (12) is connected to the inlet end of the first hot particle storage tank (02), forming a mechanical return path for room temperature / hot particles from bottom to top. The system has asymmetric drive closed-loop characteristics: the state transfer process of particles between the first moving bed heat exchanger (04), the cold particle storage tank (06) and the second moving bed heat exchanger (08) is driven by gravity; The conveying device (12) is configured to receive particles at the second hot particle storage tank (10) and return the particles to the first hot particle storage tank (02).

2. The asymmetric moving bed cold storage system according to claim 1, characterized in that, The first moving bed heat exchanger (04) and the second moving bed heat exchanger (08) are respectively provided with a first diffuser (05) and a second diffuser (09) at the gas inlet to guide the gas to pass through the bed uniformly.

3. The asymmetric moving bed cold storage system according to claim 1, characterized in that, The first moving bed heat exchanger (04) and the second moving bed heat exchanger (08) are respectively provided with a first gas-solid separator (03) and a second gas-solid separator (07) at their gas outlets, for separating particles and gas in the heat exchange gas flow.

4. The asymmetric moving bed cold storage system according to claim 1, characterized in that, The gas pipelines of the first moving bed heat exchanger (04) and the second moving bed heat exchanger (08) are respectively equipped with openable and closable valves, which are used to independently control the on / off state of the first moving bed heat exchanger (04) and the second moving bed heat exchanger (08).

5. The asymmetric moving bed cold storage system according to claim 1, characterized in that, The cold particle storage tank (06) is located between the first moving bed heat exchanger (04) and the second moving bed heat exchanger (08) and is used to receive ultra-low temperature particles from the first moving bed heat exchanger (04). The bottom of the cold particle storage tank (06) is provided with a controlled discharge port for controlling the discharge, which serves as an intermediate buffer hub for ultra-low temperature particles when switching between the charging mode and the releasing mode.

6. A method for operating an asymmetric moving bed cold storage system according to any one of claims 1 to 5, characterized in that, Includes the following steps: Cooling mode: The particles to be cooled enter the first moving bed heat exchanger (04) and come into countercurrent contact with the extremely low temperature gas. The cooled particles enter the cold particle storage tank (06) for static storage under the action of gravity. Cooling mode: The cold particles in the cold particle storage tank (06) are supplied to the second moving bed heat exchanger (08) as needed and come into countercurrent contact with the hot air flow. The heated particles enter the second hot particle storage tank (10). Return mode: Start the conveying device (12) to return the particles in the second hot particle storage tank (10) to the first hot particle storage tank (02). The return mode can be operated independently of the charging mode and the releasing mode, or can be executed in parallel and synchronously with any of the charging mode and the releasing mode.

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