阅读说明：本技术 一种液化空气储能系统 (Liquefied air energy storage system ) 是由 徐桂芝 白子为 邓占锋 梁丹曦 宋洁 彭笑东 蔡林海 于 2020-06-05 设计创作，主要内容包括：本发明公开了一种液化空气储能系统,包括储能单元、液化单元、储存液态工质的储液单元、气化单元和释能单元：储能单元包括依次连接的压缩装置、第一换热器和冷却器；释能单元包括依次连接的膨胀装置和第二换热器；液化单元包括进口端与冷却器的出口端相通的液化装置；气化单元包括出口端与第二换热器的进口端相通的蒸发装置；储液单元包括连接于液化装置和蒸发装置之间的储液装置；蒸发装置和第二换热器之间还连通有气体缓冲装置；蒸发装置中生成的气态工质在气体缓冲装置中暂存后进入第二换热器。通过在蒸发装置和第二换热器之间设置气体缓冲装置,可以缩短液化空气储能系统调节输出频率过程中的响应时间,提高液化空气储能系统的调频性能。(The invention discloses a liquefied air energy storage system, which comprises an energy storage unit, a liquefaction unit, a liquid storage unit for storing liquid working media, a gasification unit and an energy release unit: the energy storage unit comprises a compression device, a first heat exchanger and a cooler which are connected in sequence; the energy release unit comprises an expansion device and a second heat exchanger which are connected in sequence; the liquefaction unit comprises a liquefaction device with an inlet end communicated with the outlet end of the cooler; the gasification unit comprises an evaporation device of which the outlet end is communicated with the inlet end of the second heat exchanger; the liquid storage unit comprises a liquid storage device connected between the liquefying device and the evaporating device; a gas buffer device is communicated between the evaporation device and the second heat exchanger; and the gaseous working medium generated in the evaporation device temporarily stores in the gas buffer device and then enters the second heat exchanger. By arranging the gas buffer device between the evaporation device and the second heat exchanger, the response time of the liquefied air energy storage system in the process of adjusting the output frequency can be shortened, and the frequency modulation performance of the liquefied air energy storage system is improved.)

1. The utility model provides a liquefied air energy storage system, includes energy storage unit, liquefaction unit, the stock solution unit of storing liquid working medium, gasification unit and the unit of releasing energy:

the energy storage unit comprises a compression device (1), a first heat exchanger (2) and a cooler (3) which are sequentially connected through a pipeline;

the energy release unit comprises an expansion device (10) and a second heat exchanger (9) which are communicated in sequence through a pipeline;

the liquefaction unit comprises a liquefaction device (4) with an inlet end communicated with the outlet end of the cooler (3);

the gasification unit comprises an evaporation device (7) of which the outlet end is communicated with the inlet end of the second heat exchanger (9);

the liquid storage unit comprises a liquid storage device (5) connected between the liquefying device (4) and the evaporating device (7);

the energy storage unit, the liquefaction unit, the liquid storage unit, the gasification unit and the energy release unit form a channel for flowing, heat exchanging and storing working media in a gas phase-liquid phase-gas phase manner;

the system is characterized in that a gas buffer device (8) is communicated between the evaporation device (7) and the second heat exchanger (9); the gaseous working medium generated in the evaporation device (7) temporarily stores in the gas buffer device (8) and then enters the second heat exchanger (9) so as to shorten the response time of the expansion device (10) in the process of adjusting the output frequency and/or the output power.

2. The liquefied air energy storage system according to claim 1, further comprising a high-temperature heat storage device (12) and a low-temperature heat storage device (13) which form a heat exchange circulation channel with the first heat exchanger (2) and the second heat exchanger (9), wherein a heat exchange medium is arranged in the heat exchange circulation channel;

in the high-temperature heat storage process, the heat exchange medium collects high-temperature heat generated by a gaseous working medium in the process of passing through the first heat exchanger (2) and stores the high-temperature heat in the high-temperature heat storage device (12); in the low-temperature heat storage process, the heat exchange working medium collects low-temperature heat generated in the process that the gaseous working medium passes through the second heat exchanger (9) and stores the low-temperature heat in the low-temperature heat storage device (13).

3. The liquefied air energy storage system according to claim 1, wherein a cryogenic pump (14) for increasing the fluid pressure of the liquid working medium flowing out of the liquid storage device (5) is further communicated between the evaporation device (7) and the liquid storage device (5).

4. The liquefied air energy storage system according to claim 1, wherein a cold storage device (6) is further communicated between the evaporation device (7) and the liquefaction device (4), cold energy generated by evaporation of a liquid working medium in the evaporation device (7) is collected by a cold storage medium and then stored in the cold storage device (6), and the cold energy stored by the cold storage medium in the cold storage device (6) is used for cooling the working medium in the liquefaction device (4); and a medium channel for returning cold storage medium which is released by the liquefaction device (4) and releases cold energy to the evaporation device (7) is also arranged between the liquefaction device (4) and the evaporation device (7).

5. Liquefied air energy storage system according to claim 1, wherein said gas buffer device (8) is a gas buffer tank having a cavity inside.

6. The liquefied air energy storage system according to claim 1, wherein the gas buffer tank is provided with an in-tank flow guiding structure for guiding flow so as to enable the working medium to uniformly and stably flow to the second heat exchanger (9).

7. The liquefied air energy storage system according to claim 1, wherein the working fluid is air, or a combination of air and one or more of nitrogen, oxygen, carbon dioxide, methane, and ethylene.

8. Liquefied air energy storage system according to claim 1, wherein an electric generator (11) is connected to the expansion output of the expansion device (10).

Technical Field

The invention relates to the technical field of energy power, in particular to a liquefied air energy storage system.

Background

The compressed air energy storage system is a large-scale energy storage system taking air as a medium, converts electric energy into potential energy of compressed air for storage at a power utilization low peak, and pushes a turbine to do work through compressed air to release electric energy at a power utilization high peak. The liquefied air energy storage system is a novel energy storage system provided on the basis of compressed air energy storage. Compared with a compressed air energy storage system, the liquid air energy storage system has high energy storage density, does not need a large-scale pressure storage container, breaks away from the limitation of geographical conditions, and has development and application advantages.

Participating in grid frequency modulation is one of the main application directions of the liquefied air energy storage system. In a power grid, most frequency modulation units are thermal power generating units and hydroelectric generating units, the power generating equipment is rotating machinery, and the adjustment performance is limited by mechanical inertia and physical abrasion. Meanwhile, the response time of the thermal power generating unit is long, the thermal power generating unit is not suitable for participating in frequency modulation control of a short period, and the frequency modulation capacity and performance of the hydroelectric generating unit are easily limited by regions and seasons. Wind power and photovoltaic power generation are connected to a power grid in a large scale, and higher requirements are provided for frequency modulation performance. The liquefied air energy storage system can perform bidirectional frequency modulation, namely when the load of a power grid is increased, the energy storage system discharges, and when the load of the power grid is reduced, the energy storage system charges.

In the process of frequency modulation of the turbine, the opening degree of a front valve of the turbine needs to be adjusted to realize the change of output power, and liquid air in the liquid tank needs to absorb heat and vaporize firstly and then expand to do work, so that the response time of the system in the frequency modulation process is prolonged, and the frequency modulation performance of the system is not facilitated. In order to solve the problem, the invention provides a novel liquefied air energy storage system with a gas buffer device added in front of a turbine, so that the response time of the liquefied air energy storage system is shortened, and the application and popularization of the liquefied air energy storage technology in the field of power grid frequency modulation are realized.

Disclosure of Invention

In view of the above, the present invention provides a liquefied air energy storage system using a gas buffer device to improve the frequency modulation performance, so as to shorten the system response time and improve the frequency modulation performance of the system, aiming at the technical problem that the response time is long in the frequency modulation process of the liquefied air energy storage system in the prior art.

In order to solve the technical problems, the technical scheme of the invention is as follows:

the utility model provides a liquefied air energy storage system, includes energy storage unit, liquefaction unit, the stock solution unit of storing liquid working medium, gasification unit and the unit of releasing energy:

the energy storage unit comprises a compression device, a first heat exchanger and a cooler which are sequentially connected through a pipeline;

the energy release unit comprises an expansion device and a second heat exchanger which are communicated in sequence through a pipeline;

the liquefaction unit comprises a liquefaction device with an inlet end communicated with the outlet end of the cooler;

the gasification unit comprises an evaporation device of which the outlet end is communicated with the inlet end of the second heat exchanger;

the liquid storage unit comprises a liquid storage device connected between the liquefying device and the evaporating device;

the energy storage unit, the liquefaction unit, the liquid storage unit, the gasification unit and the energy release unit form a channel for flowing, heat exchanging and storing working media in a gas phase-liquid phase-gas phase manner;

a gas buffer device is communicated between the evaporation device and the second heat exchanger; the gaseous working medium generated in the evaporation device temporarily stores in the gas buffer device and then enters the second heat exchanger so as to shorten the response time of the expansion device in the process of adjusting the output frequency and/or the output power;

in the energy storage stage, the gaseous working medium is compressed by the compression device and then sequentially passes through the first heat exchanger and the cooler to be gradually cooled, and the cooled gaseous working medium is liquefied by the liquefying device and then stored in the liquid storage device; in the energy releasing stage, the liquid working medium in the liquid storage device is evaporated by the evaporation device to form a gaseous working medium, and then the gaseous working medium enters the gas buffer device for temporary storage, and then the gaseous working medium is heated by the second heat exchanger and then enters the expansion device for expansion work.

The heat exchanger comprises a first heat exchanger, a second heat exchanger, a high-temperature heat storage device and a low-temperature heat storage device, wherein the first heat exchanger and the second heat exchanger form a heat exchange circulation channel;

in the high-temperature heat storage process, the heat exchange medium collects high-temperature heat generated in the process that the gaseous working medium passes through the first heat exchanger and stores the high-temperature heat in the high-temperature heat storage device; in the low-temperature heat storage process, the heat exchange working medium collects low-temperature heat generated in the process that the gaseous working medium passes through the second heat exchanger and stores the low-temperature heat in the low-temperature heat storage device.

Further, a cryogenic pump for increasing the fluid pressure of the liquid working medium flowing out of the liquid storage device is communicated between the evaporation device and the liquid storage device.

Further, a cold storage device is communicated between the evaporation device and the liquefaction device, cold energy generated by evaporation of the liquid working medium in the evaporation device is collected by a cold storage medium and then stored in the cold storage device, and the cold energy stored in the cold storage medium in the cold storage device is used for cooling the working medium in the liquefaction device; and a medium channel for returning cold storage medium which is released by the liquefaction device (4) and releases cold energy to the evaporation device is also arranged between the liquefaction device and the evaporation device.

Further, the gas buffer device is a gas buffer tank with a cavity inside.

Furthermore, the gas buffer tank is provided with an in-tank flow guide structure for guiding flow so as to enable the working medium to uniformly and stably flow to the second heat exchanger.

Further, the working medium is air or a combination of air and one or more of R123 refrigerant, propane and pentane.

Further, an expansion output end of the expansion device is connected with a generator.

The technical scheme of the invention has the following advantages:

1. in the liquefied air energy storage system provided by the invention, in the energy storage stage, a gaseous working medium is compressed by the compression device and then sequentially passes through the first heat exchanger and the cooler to be gradually cooled, and the cooled gaseous working medium is liquefied by the liquefaction device and then stored in the liquid storage device; in the energy releasing stage, liquid working media in the liquid storage device are evaporated by the evaporation device to form gaseous working media, then the gaseous working media enter the gas buffering device for temporary storage, and then the gaseous working media are heated by the second heat exchanger and enter the expansion device for expansion work; compared with the prior art, the method that the liquid working medium absorbs heat and vaporizes firstly and then expands to do work can shorten the response time of the liquefied air energy storage system in the process of adjusting the output frequency and/or the output power, improve the frequency modulation performance of the liquefied air energy storage system, and realize the application and popularization of the liquefied air energy storage technology in the field of power grid frequency modulation.

2. According to the liquefied air energy storage system provided by the invention, cold energy generated by evaporation of the stored gas working medium is arranged between the evaporation device and the liquefaction device and used for reducing the temperature in the liquefaction device, so that the liquefaction rate of the gas working medium in the liquefaction device can be improved.

3. According to the liquefied air energy storage system provided by the invention, the first heat exchanger and the high-temperature heat storage device are used for storing high-temperature heat generated in the compression process of the gaseous medium, the second heat exchanger and the low-temperature heat storage device are used for storing low-temperature heat generated in the expansion process of the gaseous medium, and the first heat exchanger, the high-temperature heat storage device, the second heat exchanger and the low-temperature heat storage device can form an energy circulation channel, so that the recovery and utilization of system energy can be realized, and the energy storage efficiency of the system is improved.

4. According to the liquefied air energy storage system provided by the invention, the in-tank flow guide structure is arranged in the gas buffer tank, and after the working medium generated by vaporization of the evaporation device is subjected to the flow guide effect of the in-tank flow guide structure in the gas buffer tank, the working medium can be uniformly and stably conveyed into the second heat exchanger for a long time, so that the frequency modulation performance of the liquefied air energy storage system is improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

Fig. 1 is a schematic structural diagram of a liquefied air energy storage system according to an embodiment of the present invention.

Description of reference numerals: 1. a compression device; 2. a first heat exchanger; 3. a cooler; 4. a liquefaction plant; 5. a liquid storage device; 6. a cold storage device; 7. an evaporation device; 8. a gas buffer device; 9. a second heat exchanger; 10. an expansion device; 11. a generator; 12. a high temperature heat storage device; 13. a low temperature heat storage device; 14. a cryogenic pump.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

In addition, the technical features involved in the different embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

The liquefied air energy storage system shown in fig. 1 includes an energy storage unit, a liquefaction unit, a liquid storage unit for storing a liquid working medium, a gasification unit, and an energy release unit. The energy storage unit comprises a compression device 1, a first heat exchanger 2 and a cooler 3 which are sequentially connected through pipelines. The energy release unit comprises a second heat exchanger 9 and an expansion device 10 which are communicated in sequence through a pipeline, and the expansion output end of the expansion device 10 is connected with a generator 11. The liquefaction unit comprises a liquefaction device 4 having an inlet end in communication with the outlet end of the cooler 3. The gasification unit comprises an evaporation device 7, the outlet end of which is communicated with the inlet end of the second heat exchanger 9. The liquid storage unit comprises a liquid storage device 5 connected between the liquefaction device 4 and the evaporation device 7. The energy storage unit, the liquefaction unit, the liquid storage unit, the gasification unit and the energy release unit form a channel for flowing, heat exchanging and storing working media in a gas phase-liquid phase-gas phase manner; a gas buffer device 8 is also communicated between the evaporation device 7 and the second heat exchanger 9; the gaseous working medium generated in the evaporation device 7 temporarily stores in the gas buffer device 8 and then enters the second heat exchanger 9, so that the response time of the expansion device 10 in the process of adjusting the output frequency and/or the output power is shortened.

In this embodiment, the liquefied air energy storage system further includes a heat storage unit, the heat storage unit includes a high-temperature heat storage device 12 and a low-temperature heat storage device 13, which form a heat exchange circulation channel with the first heat exchanger 2 and the second heat exchanger 9, and a heat exchange medium is arranged in the heat exchange circulation channel. In the high-temperature heat storage process, the heat exchange medium collects high-temperature heat generated by the gaseous working medium in the process of passing through the first heat exchanger 2 and stores the high-temperature heat in the high-temperature heat storage device 12; in the low-temperature heat storage process, the heat exchange working medium collects low-temperature heat generated in the process that the gaseous working medium passes through the second heat exchanger 9 and stores the low-temperature heat in the low-temperature heat storage device 13. Moreover, the high-temperature heat stored in the high-temperature heat storage device 12 can be used for heating the gaseous working medium in the second heat exchanger 9, and the low-temperature heat stored in the low-temperature heat storage device 13 can be used for cooling the gaseous working medium in the first heat exchanger 2. By storing high-temperature heat generated in the compression process of the gaseous medium by using the first heat exchanger 2 and the high-temperature heat storage device 12 and storing low-temperature heat generated in the expansion process of the gaseous medium by using the second heat exchanger 9 and the low-temperature heat storage device 13, the recovery and utilization of system energy can be realized, and the energy storage efficiency of the system is improved.

In this embodiment, a cold storage device 6 is further communicated between the evaporation device 7 and the liquefaction device 4, cold energy generated by evaporation of a liquid working medium in the evaporation device 7 is collected by a cold storage medium and then stored in the cold storage device 6, and the cold energy stored by the cold storage medium in the cold storage device 6 is used for cooling the working medium in the liquefaction device 4; a medium channel for the cold storage medium which is released by the liquefaction device 4 and flows back to the evaporation device 7 is also arranged between the liquefaction device 4 and the evaporation device 7. The arrangement of the cold storage device 6 can improve the liquefaction efficiency of the liquefied air energy storage system.

In this embodiment, a cryogenic pump 14 for increasing the fluid pressure of the liquid working medium flowing out of the liquid storage device 5 is further communicated between the evaporation device 7 and the liquid storage device 5. The cryogenic pump 14 can pressurize the low-temperature liquid working medium flowing out of the liquid storage device 5, improve the flow and pressure of the subsequent low-temperature liquid working medium when the low-temperature liquid working medium is vaporized to form a gaseous working medium, and can better provide high-pressure gas as a power generation medium for the power generation device.

Specifically, the gas buffer device 8 is a gas buffer tank having a cavity therein. The number of the gas buffer tanks can be one or more, and a plurality of gas buffer tanks can be communicated between the evaporation device 7 and the second heat exchanger 9 in a parallel or serial mode. Preferably, the gas buffer tank is provided with an in-tank flow guide structure for guiding flow so as to enable the working medium to uniformly and stably flow to the second heat exchanger 9. After gaseous working media generated by vaporization of the evaporation device are subjected to the flow guide effect of the flow guide structure in the tank in the gas buffer tank, the working media can be uniformly and stably conveyed into the second heat exchanger 9 for a long time, so that the frequency modulation performance of the liquefied air energy storage system is improved.

Specifically, the working medium flowing in the liquefied air energy storage system can be R123 refrigerant, propane, pentane or a combination thereof.

In summary, the working principle of the liquefied air energy storage system provided by the embodiment of the invention is as follows: in the process of the energy storage stage, the gaseous working medium is compressed by the compression device 1 and then sequentially passes through the first heat exchanger 2 and the cooler 3 to be gradually cooled, and the cooled gaseous working medium is liquefied by the liquefying device 4 and then stored in the liquid storage device 5; in the process of the energy release stage, the liquid working medium in the liquid storage device 5 is evaporated by the evaporation device 7 to form a gaseous working medium, and then the gaseous working medium enters the gas buffer device 8 for temporary storage, and then the gaseous working medium is heated by the second heat exchanger 9 and then enters the expansion device 10 for expansion to do work; compared with the prior art, the method that the liquid working medium absorbs heat and vaporizes firstly and then expands to do work can shorten the response time of the liquefied air energy storage system in the process of adjusting the output frequency and/or the output power, improve the frequency modulation performance of the liquefied air energy storage system, and realize the application and popularization of the liquefied air energy storage technology in the field of power grid frequency modulation.

It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.