High-grade cold energy storage system based on liquid air energy storage system

Abstract

According to the high-grade cold energy storage system based on the liquid air energy storage system, liquid air in a liquid air storage tank (1) is pressurized to be in a high-pressure state through a liquid air pump (2) and then enters the tower from the tower top of a cold storage device (3), cold energy is recycled through a cold storage layer (4), and then cold energy is recycled through a reboiler (5); according to the high-grade cold energy storage system based on the liquid air energy storage system, all the cold storage layers are separated in the cold storage device (3), and the problem of axial heat conduction of thermocline layers in a solid phase cold storage mode is solved; and meanwhile, the regenerator realizes multi-stage storage of high-grade cooling capacity through the solid-phase cold accumulation layer and the single-stage phase change reboiler.

Description

Technical Field

[0001] This application relates to the technical field of cold energy storage equipment, and particularly to a high-grade cold energy storage system based on a liquid air energy storage system. Background Art

[0002] With the development of technology and economy, the demand for energy by humans is increasing. However, fossil energy is becoming increasingly depleted, and renewable energy sources such as solar energy and wind energy can be used as alternatives to make up for the use of fossil fuels. Statistical data from the International Energy Agency (IEA) shows that in July 2023, China's net power generation was 855,555.9 GWh, of which the power generation from renewable energy was 263,182.7 GWh, accounting for 30.8%. However, renewable energy has volatility and intermittency, which brings many problems to its grid connection and causes great difficulties in the utilization of renewable energy. At the same time, in China, the peak regulation of the power grid mainly relies on coal-fired generating units to achieve peak regulation of the power grid. However, the frequent start-stop and variable load operation of the units will reduce the service life and power generation efficiency of the equipment. For the above two problems, the liquid air energy storage technology is an effective solution.

[0003] The cold energy storage unit is the core unit of the liquid air energy storage system, and the recovery efficiency of cold energy will significantly affect the round-trip efficiency of the system. There are currently three ways of cold energy storage: solid-phase cold energy storage, liquid-phase cold energy storage, and phase-change cold energy storage. The solid-phase cold energy storage method uses materials such as stones as the cold energy storage medium and fills it in the cold energy storage device. It has the advantages of low cost and simple structure. However, there is a thermocline inside it, and axial heat conduction will inevitably occur, resulting in a low cold energy storage efficiency of the system. The liquid-phase cold energy storage method has a high cold energy storage efficiency, but it is expensive and has certain safety hazards. Phase-change cold energy storage has the advantage of stable cold energy storage temperature. However, phase-change cold energy storage materials are often used in multiple stages to ensure that the temperature difference between the cold energy storage medium and air is small and reduce the entropy increase of the system. Summary of the Invention

[0004] In view of this, it is necessary to provide a high-grade cold energy storage system based on a liquid air energy storage system that only uses single-stage phase-change cold energy storage to achieve multi-stage storage of high-grade cold energy, aiming at the technical problems existing in the current cold energy storage methods that often rely on only one cold energy storage method.

[0005] To solve the above problems, this application adopts the following technical solutions:

[0006] One of the purposes of this application is to provide a high-grade cold energy storage system based on a liquid air energy storage system, including: a liquid air storage tank (1), a liquid air pump (2), a cold energy storage device (3), a cold energy storage layer (4), and a reboiler (5). The cold energy storage layer (4) is arranged inside the cold energy storage device (3), where:

[0007] The liquid air in the liquid air storage tank (1) is pressurized to a high pressure state by the liquid air pump (2), then enters the tower from the top of the cold accumulator (3), recovers cold energy through the cold storage layer (4), and then recovers cold energy through the reboiler (5).

[0008] In some embodiments, it further includes another cold accumulator (6). Low-temperature gas is generated at the top of the cold accumulator (3), and the heated liquid air is generated at the bottom of the cold accumulator (3). The low-temperature gas and the liquid air enter the other cold accumulator (6) to recover low-grade cold energy.

[0009] In some embodiments, the cold accumulator (3) is of a tower structure, and the reboiler is at the bottom of the tower.

[0010] In some embodiments, the cold storage layer (4) is filled with multiple layers of solid-phase cold storage materials, and the cold storage materials of each layer are arranged at intervals.

[0011] In some embodiments, one end of the reboiler (5) is filled with a solid-liquid phase change material.

[0012] In some embodiments, the solid-phase cold storage material includes granite particles or limestone particles or basalt particles.

[0013] In some embodiments, the solid-liquid phase change material includes propane or butene or propylene or methane.

[0014] The present application adopts the above technical solutions, and the beneficial effects are as follows:

[0015] The high-grade cold energy storage system based on the liquid air energy storage system provided by the present application. The liquid air in the liquid air storage tank (1) is pressurized to a high pressure state by the liquid air pump (2), then enters the tower from the top of the cold accumulator (3), recovers cold energy through the cold storage layer (4), and then recovers cold energy through the reboiler (5). For the above high-grade cold energy storage system based on the liquid air energy storage system, the cold accumulator (3) separates each cold storage layer, solving the problem of axial heat conduction of the thermocline in the solid-phase cold storage method; at the same time, this cold accumulator realizes multi-stage storage of high-grade cold energy through the solid-phase cold storage layer and the single-stage phase change reboiler. Description of the Drawings

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required for describing the embodiments of the present application or the prior art. Obviously, the following described drawings are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0017] Figure 1Schematic structural diagram of a high-grade cold energy storage system based on a liquid air energy storage system provided by an embodiment of the present invention;

[0018] Figure 2 Schematic structural diagram of the cold storage layer provided by an embodiment of the present invention. Detailed implementation manners

[0019] The embodiments of the present application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present application, and should not be construed as a limitation to the present application.

[0020] In the description of the present application, it should be understood that the orientation or positional relationships indicated by the terms "upper", "lower", "horizontal", "inner", "outer", etc. are based on the orientation or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present application.

[0021] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, "a plurality of" means two or more unless otherwise specifically defined.

[0022] In order to make the purpose, technical solutions and advantages of the present application more clear, the present application will be further described in detail below with reference to the accompanying drawings and embodiments.

[0023] Please refer to Figure 1 , a schematic structural diagram of a high-grade cold energy storage system based on a liquid air energy storage system provided by an embodiment of the present application, including a liquid air storage tank (1), a liquid air pump (2), a cold accumulator (3), a cold storage layer (4) and a reboiler (5), and the cold storage layer (4) is arranged in the cold accumulator (3). The connection relationships and implementation manners of each component are described in detail below.

[0024] In this embodiment, the cold accumulator (3) has a tower structure, and the reboiler (5) is at the bottom of the tower.

[0025] Please refer to Figure 2 , a schematic structural diagram of the cold storage layer (4). In this embodiment, the cold storage layer (4) arranged in the tower of the cold accumulator (3) is filled with multiple layers of solid-phase cold storage materials, and a certain interval is provided between each layer of cold storage materials. One end of the reboiler (5) is filled with a solid-liquid phase change material.

[0026] In this embodiment, the solid-phase cold storage material includes materials such as granite particles, limestone particles, or basalt particles. It can be understood that the solid-phase cold storage material is not limited to the above materials, and other solid-phase cold storage materials that can achieve the same function are also within the protection scope of this application.

[0027] In this embodiment, the solid-liquid phase change material includes materials such as propane, butene, propylene, and methane. It can be understood that the solid-liquid phase change material is not limited to the above materials, and other solid-liquid phase change cold storage materials that can achieve the same function are also within the protection scope of this application.

[0028] The high-grade cold energy storage system based on the liquid air energy storage system provided in the above embodiments of this application has the following working process:

[0029] When the liquid air energy storage system is in the energy release period, the liquid air in the liquid air storage tank (1) is pressurized to a high-pressure state by the liquid air pump (2), and then the liquid air enters the tower from the top of the cold storage device (3) after pressurization. After passing through a distributor (not shown in the figure), the liquid air uniformly passes through the cold storage layer (4) from top to bottom, and its cold energy is recovered by each layer of the cold storage layer. When the liquid air reaches the bottom of the cold storage device (3), its cold energy is recovered by the phase change material in the reboiler (5), and a part of the liquid air vaporizes to form rising gas, passing through each layer of the cold storage layer. After the cold storage is completed, low-temperature and high-pressure air is generated at the top of the cold storage device (3), and the heated liquid air flows out at the bottom of the cold storage device (3), and then enters the next-stage cold storage device to recover low-grade cold energy. The cold storage device separates each cold storage layer, solving the problem of axial heat conduction of the thermocline in the solid-phase cold storage method; at the same time, only one-stage phase change cold storage material is used in this cold storage device to store high-grade cold energy.

[0030] In this embodiment, it further includes other cold storage devices (6). Low-temperature gas is generated at the top of the cold storage device (3), and heated liquid air is generated at the bottom of the cold storage device (3). The low-temperature gas and the liquid air enter the other cold storage devices (6) to recover low-grade cold energy.

[0031] It can be understood that during the energy storage process, the cold storage device (3) is turned upside down, and the liquid air enters from the top reboiler. When passing through each cold storage layer, the high-grade cold energy inside is respectively recovered, and the liquid air with a lower temperature is obtained at the bottom of the tower, realizing the recovery of high-grade cold energy.

[0032] The present application provides a high-quality cold energy storage system based on a liquid air energy storage system. The liquid air in the liquid air storage tank (1) is pressurized to a high pressure state by the liquid air pump (2) and then enters the tower from the top of the cold storage device (3). The cold energy is recovered through the cold storage layer (4) and then recovered through the reboiler (5). In the high-quality cold energy storage system based on a liquid air energy storage system, the cold storage layers are separated in the cold storage device (3), thereby solving the problem of axial heat conduction of the thermocline in the solid phase cold storage method. At the same time, the cold storage device realizes multi-stage storage of high-quality cold energy through the solid phase cold storage layer and the single-stage phase change reboiler.

[0033] It can be understood that the technical features of the above-described embodiments can be arbitrarily combined. In order to make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0034] The above are only preferred embodiments of the present application, and only specifically describe the technical principles of the present application. These descriptions are only for explaining the principles of the present application and cannot be interpreted as limiting the scope of protection of the present application in any way. Based on the explanation here, any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application, and other specific implementation methods of the present application that can be associated with the technicians in this field without creative work, should be included in the scope of protection of the present application.

Claims

1. A high-grade cold energy storage system based on a liquid air energy storage system, characterized in that, Comprising: A liquid air storage tank (1), a liquid air pump (2), a cold accumulator (3), a cold storage layer (4) and a reboiler (5), wherein the cold storage layer (4) is arranged in the cold accumulator (3), and: The liquid air in the liquid air storage tank (1) is pressurized to a high pressure state by the liquid air pump (2), then enters the tower from the top of the cold accumulator (3), recovers cold energy through the cold storage layer (4), and then recovers cold energy through the reboiler (5).

2. The high-grade cold energy storage system based on the liquid air energy storage system according to claim 1, characterized in that, It further comprises other cold accumulators (6). Low-temperature gas is generated at the top of the cold accumulator (3), and the liquid air after temperature rise is generated at the bottom of the cold accumulator (3). The low-temperature gas and the liquid air enter the other cold accumulators (6) to recover low-grade cold energy.

3. The high-grade cold energy storage system based on the liquid air energy storage system according to claim 1, characterized in that, The cold accumulator (3) is of a tower structure, and the reboiler (5) is at the bottom of the tower.

4. The high-grade cold energy storage system based on a liquid air energy storage system according to claim 3, characterized in that The cold storage layer (4) is filled with multiple layers of solid-phase cold storage materials, and the cold storage materials of each layer are arranged at intervals.

5. The high-grade cold energy storage system based on a liquid air energy storage system according to claim 4, characterized in that, One end of the reboiler (5) is filled with a solid-liquid phase change material.

6. The high-grade cold energy storage system based on a liquid air energy storage system according to claim 4, characterized in that The solid-phase cold storage material comprises granite particles or limestone particles or basalt particles.

7. The high-grade cold energy storage system based on a liquid air energy storage system according to claim 5, characterized in that, The solid-liquid phase change material comprises propane or butene or propylene or methane.

Images