Breathing air storage tank

Abstract

The utility model provides a breathing air storage tank which comprises a metal tank body, a flexible air bag is arranged in the metal tank body, the flexible air bag divides the space in the metal tank body into an air cavity and a gaseous working medium cavity, the pressure of the air cavity is 0.7-3.5 Mpa, the pressure of the gaseous working medium cavity is the same as that of the air cavity, the air cavity is communicated with an air inlet and an air outlet respectively, and the air inlet is communicated with the air outlet. The gaseous working medium cavity is communicated with the working medium inlet and the working medium outlet. The gas working medium is dedusted in the metal tank at 0.7-3.5 Mpa, and compared with a normal-temperature and normal-pressure storage mode, the space occupied by the gas storage device is greatly reduced, so that the space cost is saved. Meanwhile, the cost of the air bag for air storage in the market is far higher than that of a metal tank body, the use amount of the air bag is reduced in the mode that the metal tank body can store pressurized air, and the overall cost of the air storage device is greatly reduced. In addition, the gaseous working medium in the breathing gas storage tank is in a pressurized state of 0.7-3.5 Mpa, so that the gaseous working medium is more convenient to pressurize again to liquefy the gaseous working medium.

Description

Technical Field

[0001] The utility model relates to the field of carbon dioxide energy storage, in particular to a breathing gas storage tank. Background Art

[0002] Carbon dioxide energy storage (CES) technology is a new type of physical energy storage technology based on compressed air energy storage (CAES) and Brayton power generation cycle. The energy storage time can exceed 16 hours, and the energy release power can reach GW level. It has the advantages of high energy storage density, long operating life, and compact system equipment. It is suitable for large-scale long-term energy storage and has good development and application prospects. In the existing technical application, during the low electricity price period, the normal pressure gaseous carbon dioxide is converted into high pressure liquid carbon dioxide through a multi-stage compressor, and the electrical energy is converted into the form of carbon dioxide internal energy for storage; during the peak electricity consumption period, the high pressure liquid carbon dioxide is expanded into normal pressure gaseous carbon dioxide through a multi-stage expander to generate electricity, and finally realize the storage and release of electrical energy.

[0003] However, the equipment cost investment required to operate this energy storage system cannot be ignored. Taking the 16MW carbon dioxide energy storage system as an example, 180 tons of liquid carbon dioxide needs to be circulated and phase-changed in the system. When converted into gaseous carbon dioxide at normal temperature and pressure, its volume will exceed 100,000 cubic meters. At the same time, the phase change between normal-pressure gaseous carbon dioxide and high-pressure liquid carbon dioxide needs to be achieved, which will require the investment of multi-stage large compressors and multi-stage large expanders. Due to the huge cost investment, the cost of technology promotion cannot be ignored, and there will be huge challenges in marketization. Utility Model Content

[0004] In order to solve the above technical problems, the utility model provides a breathing gas storage tank, which has the characteristic of reducing costs.

[0005] The specific technical scheme is as follows: A breathing gas storage tank comprises a metal tank body, wherein a flexible air bag is arranged inside the metal tank, wherein the flexible air bag divides the space inside the metal tank body into an air cavity and a gaseous working fluid cavity, wherein the pressure of the air cavity is 0.7-3.5Mpa, the pressure of the gaseous working fluid cavity is the same as that of the air cavity, the air cavity is respectively connected to an air inlet and an air outlet, and the gaseous working fluid cavity is respectively connected to a working fluid inlet and a working fluid outlet.

[0006] Through the above technical solution, the gaseous working medium is dusted at 0.7-3.5Mpa in the metal tank, which greatly reduces the space occupied by the gas storage device compared with the storage method at normal temperature and pressure, thereby saving space costs. At the same time, the cost of the airbag used for gas storage on the market is much greater than the cost of the metal tank body. The method of storing pressurized gas in the metal tank body reduces the use of airbags, which greatly reduces the overall cost of the gas storage device. In addition, the gaseous working medium in the breathing gas tank is in a pressurized state of 0.7-3.5Mpa, which makes it easier to pressurize the gaseous working medium again to liquefy it.

[0007] Preferably, the working fluid is carbon dioxide.

[0008] Through the above technical solution, using carbon dioxide as the working fluid is more conducive to liquefied energy storage. Specifically, the conditions for liquefaction of carbon dioxide are easier to achieve than those for air.

[0009] Preferably, the air inlet is connected to an air compression device, and the air outlet is connected to a turbine generator.

[0010] Through the above scheme, in the low-electricity-price working fluid energy storage stage, the gaseous working fluid is consumed, and compressed air can be introduced into the air cavity in the breathing air tank through the air compression device to maintain the pressure in the breathing air tank. In the high-electricity-price working fluid energy release stage, the working fluid gasification volume increases, and the compressed air flows out from the air outlet and is converted into electrical energy by the turbine generator, so that the liquefied working fluid energy storage and compressed air energy storage can be carried out simultaneously.

[0011] Preferably, the gaseous working fluid chamber is connected to the energy storage system in a closed loop via a working fluid inlet and a working fluid outlet.

[0012] Through the above technical solution, the breathing gas storage tank is used to store 0.7-3.5Mpa gaseous working fluid.

[0013] Preferably, the middle portion of the flexible airbag is fixedly connected to the middle portion of the metal can body.

[0014] Through the above technical solution, when the gaseous working medium in the flexible airbag is consumed in large quantities, the flexible airbag is prevented from being folded multiple times under the action of its own gravity.

[0015] Preferably, a woven net bag is installed between the metal tank body and the flexible airbag, and the woven net bag is fixedly connected to the metal tank body.

[0016] Through the above technical solution, when the gaseous working medium in the flexible airbag is consumed in large quantities, the woven net bag can be used to support the flexible airbag to prevent the weight of the flexible airbag from being borne solely by the middle connection structure, thereby reducing the service life of the flexible airbag.

[0017] The beneficial effects of the utility model are:

[0018] 1. Use high-pressure metal gas storage tanks with a pressure of 0.7-3.5Mpa to replace the normal pressure gas storage membrane. The equipment volume will be reduced from 100,000 cubic meters to about 12,000 cubic meters, which will greatly reduce the equipment cost in the gas storage part.

[0019] 2. Compared with normal pressure carbon dioxide, the carbon dioxide gas pressure in the metal gas tank increases 10 times. During the operation of the whole system, the compression ratio and expansion ratio of carbon dioxide in the phase change process will be greatly reduced. Finally, the carbon dioxide phase change process can be realized through a single-stage small compressor and a low-temperature pressure reducing valve, which greatly reduces the equipment cost in the whole system. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the following briefly introduces the drawings required for the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0021] Figure 1 This is a schematic structural diagram of Example 1 when the gaseous working medium chamber is full of working medium;

[0022] Figure 2 This is a schematic diagram of the structure when the working medium in the gaseous working medium chamber of Example 1 is completely discharged;

[0023] Figure 3 It is a schematic diagram of the structure of the liquefied energy storage system;

[0024] 1. Metal tank body, 11. Air cavity, 12. Gaseous working medium cavity, 13. Air inlet, 14. Air outlet, 15. Working medium inlet, 16. Working medium outlet, 17. Air compression device, 18. Turbine generator, 2. Flexible airbag, 3. Woven net bag, 41. Compressor, 42. Cooling device, 43. Liquid storage tank, 44. Gasification conversion device. DETAILED DESCRIPTION

[0025] In order to make the above-mentioned purposes, features and advantages of the utility model more obvious and easy to understand, the specific implementation methods of the utility model are described in detail below in conjunction with the drawings of the specification. In the following description, many specific details are set forth to facilitate a full understanding of the utility model, but the utility model can also be implemented in other ways different from those described herein, and those skilled in the art can make similar generalizations without violating the connotation of the utility model, so the utility model is not limited by the specific embodiments disclosed below.

[0026] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0027] Example 1

[0028] like Figure 1-2 As shown, a breathing gas storage tank includes a metal tank body 1 for storing gaseous working fluid in a liquefied energy storage system. In this embodiment, the working fluid is carbon dioxide. A flexible airbag 2 is arranged in the metal tank body 1. The flexible airbag 2 is deformable and does not bear tension. The flexible airbag 2 divides the space in the metal tank body 1 into an air cavity 11 and a gaseous working fluid cavity 12. The pressure of the air cavity 11 is 0.7-3.5Mpa, and 1Mpa is used in this embodiment. The pressure of the gaseous working fluid cavity 12 is the same as that of the air cavity 11. The air cavity 11 is respectively connected to the air inlet 13 and the air outlet 14, and the gaseous working fluid cavity 12 is respectively connected to the working fluid inlet 15 and the working fluid outlet 16. The air inlet 13 is connected to the air compression device 17, and the air outlet 14 is connected to the turbine generator 18. The gaseous working fluid cavity 12 is connected to the energy storage system in a closed loop through the working fluid inlet 15 and the working fluid outlet 16.

[0029] The middle part of the flexible airbag 2 is fixedly connected to the middle part of the metal tank body 1. A woven net bag 3 is installed between the metal tank body 1 and the flexible airbag 2, and the woven net bag 3 is fixedly connected to the metal tank body 1. Specifically, the flexible airbag 2 is connected to the metal tank body 1 through a connecting structure, and the connecting structure passes through the mesh holes on the woven net bag 3; or the flexible airbag 2 is bonded to the metal tank body 1 at the mesh holes of the woven net bag 3.

[0030] like Figure 3 As shown, the liquefied energy storage system includes a liquefaction device, a liquid storage tank, a gasification conversion device and a thermal cycle device. The liquefaction device includes a compressor 41 and a cooling device 42. The compressor 41 is connected to the working medium outlet 16. The compressor 41 pressurizes the carbon dioxide in the breathing gas storage tank and transports it to the cooling device 42 for cooling and liquefaction. The liquefied liquid carbon dioxide flows into the liquid storage tank 43 for storage to complete the process of working medium liquefaction energy storage. The liquid carbon dioxide is decompressed and gasified in the gasification conversion device 44 and then flows into the breathing gas storage tank. The thermal cycle device can absorb the heat generated by the compressor 41 during pressurization to heat the gaseous carbon dioxide after the liquid carbon dioxide is gasified.

[0031] The operation process of the breathing air tank is divided into two stages according to the operation of the whole system, the energy storage process and the energy release process.

[0032] Energy storage process: At night when electricity prices are low, the low-pressure gaseous carbon dioxide in the breathing gas storage tank is discharged from the working fluid outlet 16. At this time, the pressure of the gaseous working fluid chamber 12 decreases. In order to maintain the pressure of the gaseous working fluid chamber 12 at 1Mpa, the air compression device 17 starts working and pumps air into the air cavity of the breathing gas storage tank.

[0033] Release process: During the day when electricity prices are high, the high-pressure liquid carbon dioxide in the liquefied energy storage system expands and vaporizes to generate low-pressure gaseous carbon dioxide, which enters the gaseous working fluid cavity of the breathing gas storage tank. The pressure of the gaseous working fluid cavity gradually increases. In order to maintain the pressure in the tank, the air cavity outlet is opened to discharge air. The discharged air can be used to generate electricity through a turbine generator.

[0034] It should be noted that the above embodiments are only used to illustrate the technical solution of the utility model rather than to limit it. Although the utility model has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the utility model, which should be included in the scope of the claims of the utility model.

Claims

1. A breathing air storage tank, characterized in that: The invention comprises a metal tank body (1) for storing gaseous working fluid in a liquefied energy storage system, wherein a flexible airbag (2) is arranged in the metal tank body (1), and the flexible airbag (2) divides the space in the metal tank body (1) into an air cavity (11) and a gaseous working fluid cavity (12), wherein the pressure of the air cavity (11) is 0.7-3.5 Mpa, and the pressure of the gaseous working fluid cavity (12) is the same as that of the air cavity (11), and the air cavity (11) is respectively connected to an air inlet (13) and an air outlet (14), and the gaseous working fluid cavity (12) is respectively connected to a working fluid inlet (15) and a working fluid outlet (16).

2. A breathing gas storage tank according to claim 1, characterized in that: The working fluid is carbon dioxide.

3. A breathing gas storage tank according to claim 1, characterized in that: The air inlet (13) is connected to an air compression device (17), and the air outlet (14) is connected to a turbine generator (18).

4. A breathing gas storage tank according to claim 1, characterized in that: The gaseous working medium chamber (12) is connected to the energy storage system in a closed loop via a working medium inlet (15) and a working medium outlet (16).

5. A breathing gas storage tank according to claim 1, characterized in that: The middle part of the flexible airbag (2) is fixedly connected to the middle part of the metal tank body (1).

6. A breathing gas storage tank according to claim 5, characterized in that: A woven net bag (3) is installed between the metal tank body (1) and the flexible airbag (2), and the woven net bag (3) is fixedly connected to the metal tank body (1).

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