CN106091576A - The cryogenic liquefying air energy storage method of a kind of coupled solar photothermal technique and system - Google Patents

Abstract

The present invention provides energy storage method and the system of the deep cooling liquid air of a kind of solar energy techniques, said method comprising the steps of: step 1: utilize electric energy that gaseous air is converted under the conditions of cryogenic high pressure liquid air, collect described liquid air, and collect the heat energy of release in this conversion process, the described heat energy being collected is for providing hot conditions for step 2；Step 2: the described liquid air collected being converted under high-temperature and high-pressure conditions gaseous air, and collects the cold energy of release in this conversion process, the described cold energy being collected is for providing cryogenic conditions for step 1；Also include: step 3: collect and store solar energy optical-thermal, use heat energy collected in described solar energy optical-thermal and described step 1 jointly to provide hot conditions for described step 2.

Description

A cryogenic liquefied air energy storage method and system coupled with solar thermal technology

technical field

The invention relates to the technical field of energy storage of liquefied air, in particular to an energy storage method of coupling photothermal energy with cryogenic liquid air and a photothermal energy storage power generation system.

Background technique

Cryogenic liquefied air energy storage technology refers to the use of electric energy for compressed air during the low load period of the grid, and the high-pressure sealing of the air in abandoned mines, subsidence subsea gas storage tanks, caves, expired oil and gas wells or newly built gas storage wells. The energy storage method releases compressed air during the peak period to drive the steam turbine to generate electricity. The liquid air energy storage system has the advantages of large energy storage capacity, long energy storage period, small footprint and does not depend on geographical conditions. During energy storage, the electric energy compresses, cools and liquefies the air, and at the same time stores the heat energy released during the process, which is used to heat the air during energy release; during energy release, the liquid air is pressurized and vaporized, driving the expansion generator set to generate electricity, and at the same time The cold energy of the process is stored and used to cool the air while storing energy. However, the existing cryogenic liquid air energy storage system has the following defects: 1. The efficiency of the cryogenic liquid air energy storage system is low, and the heat energy used in the gasification process of liquid air in the prior art comes from the compression of gaseous air into liquid air The heat energy released during the process, due to the large loss of heat energy in the process of collection, storage and transmission, makes the conversion rate of liquid air gasification of the existing cryogenic liquid air energy storage system low, which cannot meet the use requirements. The way to solve this problem in the prior art is to add heat storage and heat exchange equipment, such as large cavernous gas storage rooms, etc., which greatly increases the cost and floor space of the system, and large cavernous gas storage rooms are also vulnerable to damage. Earthquakes and other geological disasters. 2. In addition, limited by the transfer efficiency of heat energy, the gasification rate of liquid air gasification is low, and the dynamic response speed is slow, so it is often impossible to drive the generator set to generate electricity in time.

Cryogenic liquid air energy storage systems are often used in conjunction with power stations. After storing electrical energy in the form of liquid air, a large amount of heat energy needs to be invested to complete the gasification of liquid air. In the existing cryogenic liquid air energy storage systems , the process of collecting heat energy in the process of compressing gaseous air into liquefied air is limited by heat energy loss and storage rate, and it is often necessary to provide heat energy supply in the form of burning minerals, so not only the operating cost is high, but also there is a certain degree of environmental pollution .

Contents of the invention

Therefore, the technical problem to be solved by the present invention is to overcome the technical defects of high operating cost and certain environmental pollution in the cryogenic liquefied air energy storage system in the prior art.

In order to solve the above-mentioned technical problems, the present invention provides an energy storage method for cryogenic liquid air of solar thermal technology, comprising the following steps:

Step 1: Using electric energy to convert gaseous air into liquid air under low temperature and high pressure conditions, collecting the liquid air, and collecting heat energy released during the conversion process, the collected heat energy is used to provide high temperature conditions for step 2;

Step 2: converting the collected liquid air into gaseous air under high temperature and high pressure conditions, and collecting the cold energy released during the conversion process, and the collected cold energy is used to provide low temperature conditions for step 1;

Also includes:

Step 3: Collecting and storing solar heat, using the solar heat and the heat energy collected in step 1 to provide high temperature conditions for step 2.

In the above energy storage method of coupling photothermal energy with cryogenic liquid air, the solar photothermal energy and the thermal energy collected in step 1 are stored together or separately.

In the energy storage method of the cryogenic liquid air of the above-mentioned solar thermal technology, the solar thermal energy and the thermal energy collected in the step 1 are exchanged with the heat exchange fluid, and the thermal energy carried by the heat exchange fluid is Release to the environment in which step 2 was performed.

In the energy storage method for cryogenic liquid air of the above-mentioned solar photothermal technology, the heat exchange fluid is water.

The present invention also provides a cryogenic liquid air energy storage system of solar thermal technology, including:

The energy input device is used for inputting energy into the energy storage system;

The first air compression device is driven by the energy input device to perform one-stage compression of gaseous air;

An air purification device, which purifies the gaseous air compressed in the first stage;

The second air compression device is driven by the energy input device to perform two-stage compression on the gaseous air that has undergone primary compression into liquid air, and collects it;

A heat energy recovery device that collects heat generated during the two-stage compression process and inputs the collected heat into the gasification device during the gasification process; a gasification device that pressurizes the liquid air and receives the heat energy recovery device Provide heat energy to vaporize liquid air;

The cold energy recovery device collects the cold energy generated during the gasification process of the liquid air in the gasification device, and can output the collected cold energy to the first air compression device;

The prime mover of the photothermal power station is driven by the gasification of the liquid air to generate power;

It also includes a coupled photothermal device for collecting solar photothermal energy and outputting the collected thermal energy to the liquid air to provide a high temperature environment for the gasification of the liquid air.

In the above-mentioned cryogenic liquid air energy storage system of solar photothermal technology, the heat energy recovery device is at least one heat storage tank, and the heat storage tank is connected to the coupled photothermal device and the heat energy recovery device.

In the above-mentioned energy storage system for cryogenic liquid air of solar photothermal technology, a heat exchange device is also included, and the heat exchange device is respectively connected to the heat storage tank and the gasification device; a heat exchange fluid is stored in the heat exchange device , the heat energy in the heat storage tank exchanges heat with the heat exchange fluid, and the heat exchange fluid outputs the heat energy it carries to the gasification device.

In the above-mentioned cryogenic liquid air energy storage system of solar photothermal technology, the energy input device is an electric motor, which converts electrical energy into mechanical energy and drives the first air compression device, the second air compression device and the liquefaction device to perform work .

In the above-mentioned cryogenic liquid air energy storage system of solar thermal technology, the first air compression device is a low-pressure compressor;

The second air compression device and the liquefaction device are high-pressure compressors.

In the above-mentioned cryogenic liquid air energy storage system of solar thermal technology, the prime mover of the solar thermal power station is one or any two or three of steam turbine, gas turbine or Stirling machine.

The technical solution of the present invention has the following advantages:

1. In the cryogenic liquefied air energy storage method coupled with solar photothermal technology provided by the present invention, high temperature conditions are provided for step 2 after collecting solar photothermal, thereby effectively improving the gasification rate of too air, and solar energy The collection and transportation costs of solar heat are relatively low. Compared with other ways of supplementing heat energy, solar thermal energy is obviously based on economic advantages.

2. In the cryogenic liquefied air energy storage system coupled with solar thermal technology provided by the present invention, the photothermal energy storage power generation system is used in combination with the cryogenic liquefied air energy storage system and the photothermal power station, and the solution is solved by the introduction of the photothermal power station. The heat demand of the cryogenic liquefied air energy storage system; and through the cryogenic liquefied air energy storage system, the problem that the photothermal power station is affected by the fluctuation and randomness of solar radiation is solved.

Description of drawings

In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the accompanying drawings that need to be used in the description of the specific embodiments or prior art. Obviously, the accompanying drawings in the following description The drawings show some implementations of the present invention, and those skilled in the art can also obtain other drawings based on these drawings without creative work.

Fig. 1 is a schematic diagram of the principle of the cryogenic liquefied air energy storage method and system coupled with solar thermal technology in Embodiment 2 of the present invention.

Explanation of reference signs:

1-energy input device; 2-first air compression device; 3-air purification device; 4-second air compression device and liquefaction device; 6-gasification device; 7-photothermal power plant prime mover; 8-coupled photothermal device; 9-cold energy recovery device; 12-heat storage tank; 13-heat exchange device.

detailed description

The technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Apparently, the described embodiments are some of the embodiments of the present invention, but not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to 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. The indicated orientation or positional relationship is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, or in a specific orientation. construction and operation, therefore, should not be construed as limiting the invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and should not be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that unless otherwise specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection. Connected, or integrally connected; it may be mechanically connected or electrically connected; it may be directly connected or indirectly connected through an intermediary, and it may be the internal communication of two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention in specific situations.

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 there is no conflict with each other.

Example 1

This embodiment provides an energy storage method for cryogenic liquefied air, comprising the following steps:

Step 1: Using electric energy to convert gaseous air into liquid air under low temperature and high pressure conditions, and collecting the liquid air, collecting heat energy released during the conversion process, and the collected heat energy is used to provide high temperature conditions for step 2;

Step 2: converting the collected liquid air into gaseous air under high temperature and high pressure conditions, and collecting the cold energy released during the conversion process, and the collected cold energy is used to provide low temperature conditions for step 1;

Step 3: Collecting and storing solar heat, using the solar heat and the heat energy collected in step 1 to provide high temperature conditions for step 2.

The above-mentioned implementation mode is the core technical solution of this embodiment, by collecting and storing

Affected by fluctuations and randomness of solar radiation, photothermal power stations often cannot sustain stable power transmission. The photothermal energy storage power generation system of this embodiment uses a combination of cryogenic liquefied air energy storage system It solves the heat demand of the cryogenic liquefied air energy storage system; and through the cryogenic liquefied air energy storage system, it solves the problem that the photothermal power station is affected by the fluctuation and randomness of solar radiation.

In the process of gasifying liquid air, more heat energy is required, resulting in slower gasification efficiency of liquid air. In order to solve this problem, step 3 in this embodiment collects inexhaustible solar light and heat as heat energy , part of the heat energy required in the liquid air gasification process comes from the heat energy collected in step 1, and the other part comes from solar heat. In this embodiment, step 3 collects solar heat and heat to provide high temperature conditions for step 2, thereby effectively improving the gasification rate of solar air, and the cost of collecting and transporting solar heat is low, compared to other As a way to supplement thermal energy, solar thermal energy is obviously based on economic advantages.

Further, the step 3 also includes storing the solar thermal energy and the thermal energy collected in the step 1 together or separately. For example, solar thermal energy and the thermal energy collected in step 1 can be stored separately, and the thermal energy of the two can be mixed/separately output when used; it can also be stored together with solar thermal energy and the thermal energy collected in step 1, and when used Then output the heat energy of the two together.

In order to improve the heat exchange efficiency, the step 3 also includes: exchanging the solar thermal energy and the heat energy collected in the step 1 with the heat exchange fluid, and the heat exchange fluid releases the heat energy carried by it to the In the environment where step 2 is performed. Wherein, the heat exchange fluid is preferably water. In actual use, the solar thermal energy and the heat energy collected in step 1 will rapidly heat the water from the liquid state to the gaseous state, and then the high-temperature water vapor will be passed into the described step together. 2 environment. Next, the water vapor can exchange the heat it carries with the liquid air, prompting the rapid gasification of the liquid air, and then output the gaseous air obtained by vaporizing the water vapor and the liquid air together, and the mixed gas of the two will drive the work device to do work. Complete power generation. The reason why the heat exchange fluid is preferably used in this implementation is that: on the one hand, water has a large specific heat capacity and can carry more heat energy during the process of changing from liquid to gas; on the other hand, liquid water is pollution-free and easy to obtain, and high-temperature water The steam can be output to the work device together with the gaseous air obtained after the gasification of the liquid air, which can assist the liquid air to do work.

Example 2

This embodiment provides a photothermal energy storage power generation system. The energy storage system of this embodiment will be described in detail below in conjunction with FIG. 1:

The photothermal energy storage power generation system of this embodiment includes:

The energy input device 1, that is, the motor, converts electrical energy into mechanical energy and drives the first air compression device 2 and the second air compression device 4 to do work, wherein the first air compression device 2 is a low-pressure compressor; the second air compression device 4 is High pressure compressor. Specifically, the first air compression device 2 performs primary compression on the gaseous air driven by the energy input device 1. At this time, the air compressed by the primary stage is still in a gaseous state, and then the gas compressed by the primary stage is purified by the air purification device 3. Then carry out secondary compression, the second air compression device and liquefaction device 4 compress the purified air into liquid air in a low-temperature and high-pressure environment, and collect the liquid air, for example, into storage chambers, tanks and other devices . While the two-stage compression process is in progress, the heat energy recovery device collects and stores the heat energy generated during the two-stage compression process. The mechanical energy consumed by the energy input device 1 , that is, the motor, is transformed into the internal energy of the liquid air, thereby completing the energy storage process.

In addition, the photothermal energy storage power generation system of this embodiment also includes:

Coupled photothermal device 8, the coupled photothermal device 8 is used to collect solar photothermal energy, and output the collected thermal energy to liquid air to provide a high temperature environment for the liquid air to vaporize. The coupled photothermal device 8 provides high temperature conditions for the gasification of liquid air after strong solar photothermal collection, thus effectively improving the gasification rate of too much air, and the cost of solar photothermal collection and transportation is low, compared to other supplementary In the way of thermal energy, solar thermal is clearly based on economic advantages. Specifically, the heat energy collected in the coupled photothermal device 8 can be stored together with the heat energy collected in the gaseous air compression process in the heat energy recovery device, and then in the liquid air gasification process, the heat energy is exchanged through the heat exchange device 13 .

The energy release process is:

The liquid air is stored in the liquid air storage tank, and the liquid air is output to the gasification device 6 through a cryogenic pump, and the gasification device 6 is preferably an evaporator. The gasification device 6 can pressurize the liquid air, thereby promoting the gasification and expansion of the liquid air. At the same time, since the heat storage tank and the gasification device 6 are connected through the heat exchange device 13, the thermal energy collected in the energy storage process The thermal energy collected by the coupled photothermal device 8 is exchanged with the liquid air, thereby promoting the increase of the vaporization rate of the liquid air, increasing the enthalpy of the gaseous air, and improving the work efficiency and dynamic response speed of the gaseous air.

While the liquid air is gasifying, the cold energy recovery device 9 collects the cold energy produced by the gasification of the liquid air. Since the cold energy recovery device 9 and the second air compression device 4 are connected by a cold exchanger, the cold energy recovery The cold energy collected in the device 9 can be used in the energy storage process in the first air compression device 2 and the second air compression device 4 . Furthermore, after the liquid air is vaporized into a gaseous state, it can drive the expansion unit 7 to expand and perform work, thereby completing the energy release process.

As a preferred embodiment, the heat energy recovery device is at least one heat storage tank, and the heat storage tank 12 is connected to the photothermal coupling device 8 and the heat energy recovery device. The heat exchange device 13 is respectively connected to the heat storage tank 12 and the gasification device 6; a heat exchange fluid is stored in the heat exchange device 13, and the heat energy in the heat storage tank 12 exchanges heat with the heat exchange fluid, so The heat exchange fluid outputs the heat energy it carries to the gasification device 6 .

In the actual working process, liquid air is gasified through multiple expansion processes. For example, the photoelectric hotspot prime mover 7 used in this embodiment is one or any two of a steam turbine, a gas turbine or a Stirling machine. or three. The heat exchange device 13 can be connected with the above-mentioned steam turbine, gas turbine or Stirling machine to provide heat energy for the gasification of liquid air.

In the prior art, the photothermal power station is affected by the fluctuation and randomness of solar radiation, and often cannot sustain stable power transmission. The photothermal energy storage power generation system of this embodiment uses the cryogenic liquefied air energy storage system and the photothermal power station in combination, through The introduction of the solar thermal power station solves the heat demand of the cryogenic liquefied air energy storage system; and through the cryogenic liquefied air energy storage system, the problem that the solar thermal power station is affected by the fluctuation and randomness of solar radiation is solved.

In addition, the technical means to solve the low energy storage conversion rate and slow conversion rate of cryogenic liquefied air are often: use the compression heat of the compressor to store heat to increase the temperature of the gas used for expansion power generation; need to increase heat storage and heat exchange equipment , increase the system cost, and because the demand for high-grade compression heat at the compression end increases the equipment cost, the cost of system efficiency improvement is further increased, and the large cavernous gas storage room of the compressed air energy storage system will be affected by geological disasters such as earthquakes . However, in this embodiment, the conversion rate and conversion rate of liquid air are significantly improved through the installation of the coupled photothermal device 8, without adding expensive heat storage and heat exchange equipment, which also significantly reduces the cost.

Apparently, the above-mentioned embodiments are only examples for clear description, rather than limiting the implementation. For those of ordinary skill in the art, other changes or changes in different forms can be made on the basis of the above description. It is not necessary and impossible to exhaustively list all the implementation manners here. And the obvious changes or changes derived therefrom are still within the scope of protection of the present invention.

Claims (10)

1. A method for energy storage of cryogenic liquid air coupled with solar photothermal technology, comprising the following steps: Step 1: Using electric energy to convert gaseous air into liquid air under low temperature and high pressure conditions, collecting the liquid air, and collecting heat energy released during the conversion process, the collected heat energy is used to provide high temperature conditions for step 2; Step 2: converting the collected liquid air into gaseous air under high temperature and high pressure conditions, and collecting the cold energy released during the conversion process, and the collected cold energy is used to provide low temperature conditions for step 1; It is characterized in that it also includes: Step 3: Collecting and storing solar heat, using the solar heat and the heat energy collected in step 1 to provide high temperature conditions for step 2. 2. The energy storage method of cryogenic liquid air coupled with solar thermal technology according to claim 1, characterized in that: The step 3 also includes: storing the solar thermal energy and the thermal energy collected in the step 1 together or separately. 3. The energy storage method of cryogenic liquid air coupled with solar thermal technology according to claim 2, characterized in that: After collecting and storing solar thermal energy in step 3, further: exchanging the solar thermal energy and the thermal energy collected in step 1 with the heat exchange fluid, and the heat exchange fluid releases the thermal energy it carries to In the environment where step 2 is performed. 4. The energy storage method of cryogenic liquid air coupled with solar photothermal technology according to claim 2 or 3, characterized in that: The heat exchange fluid is water. 5. A cryogenic liquid air energy storage system coupled with solar thermal technology, including: An energy input device (1), used for inputting energy into the energy storage system; The first air compression device (2) is driven by the energy input device (1) to perform one-stage compression of gaseous air; An air purification device (3), which purifies the gaseous air compressed in the first stage; The second air compression device (4), driven by the energy input device (1), performs two-stage compression on the gaseous air that has undergone primary compression into liquid air, and collects it; The heat energy recovery device collects the heat energy generated in the two-stage compression process, and inputs the collected heat into the gasification device (6) during the gasification process; the gasification device (6) pressurizes the liquid air, and receiving the thermal energy provided by the thermal energy recovery device to vaporize the liquid air; The cold energy recovery device (9) collects the cold energy generated during the gasification process of the liquid air in the gasification device (6), and can output the collected cold energy to the first air compression device (4); The prime mover (7) of the photothermal power station is driven by the gasification of the liquid air to generate power; It is characterized by: It also includes a coupled photothermal device (8), which is used to collect solar photothermal energy and output the collected thermal energy to liquid air to provide a high temperature environment for the liquid air to vaporize. 6. The energy storage system of cryogenic liquid air of solar thermal technology according to claim 5, characterized in that: The heat energy recovery device is at least one heat storage tank, and the heat storage tank (12) is connected to the photothermal coupling device (8) and the heat energy recovery device. 7. The energy storage system of cryogenic liquid air of solar thermal technology according to claim 6, characterized in that: It also includes a heat exchange device (13), the heat exchange device (13) is respectively connected to the heat storage tank (12) and the gasification device (6); a heat exchange fluid is stored in the heat exchange device (13), so The heat energy in the heat storage tank (12) exchanges heat with the heat exchange fluid, and the heat exchange fluid outputs the heat energy it carries to the gasification device (6). 8. The energy storage system for cryogenic liquid air of solar thermal technology according to claim 5, characterized in that: The energy input device (1) is an electric motor, which converts electrical energy into mechanical energy and drives the first air compression device (2), the second air compression device and the liquefaction device (4) to perform work. 9. The cryogenic liquid air energy storage system of solar thermal technology according to claim 8, characterized in that: The first air compression device (2) is a low-pressure compressor; The second air compression device and liquefaction device (4) are high-pressure compressors. 10. The energy storage system of cryogenic liquid air of solar thermal technology according to claim 5, characterized in that: The prime mover (7) of the photothermal power station is one or any two or three of steam turbine, gas turbine or Stirling machine.