Compressed air energy storage system utilizing underground aquifer and working method of compressed air energy storage system

Abstract

The invention discloses a compressed air energy storage system utilizing an underground aquifer and a working method of the compressed air energy storage system. The compressed air energy storage system comprises an air compression unit, an air expansion unit, a heat storage and circulation unit and an air injection unit. The underground aquifer is used as a gas storage for energy storage, compressed air is injected into the aquifer through the air injection system, so that a gas storage bag is formed in the aquifer, and the limitation of an energy storage system on geological conditions is reduced; and high-temperature-resistant hot oil with large specific heat capacity is used for enhancing heat exchange of compressed air, assisting an air compression expansion system, keeping isothermal characteristics in the system operation process, controlling heat loss of the system and improving the operation efficiency of the air compression system.

Description

Technical Field

[0001] The present invention belongs to the technical field of compressed air energy storage, and particularly relates to a compressed air energy storage system using an underground aquifer and a working method thereof. Background Art

[0002] With the increasing attention to greenhouse gas emissions, the share of renewable energy sources such as wind energy and solar energy has recently increased rapidly in the energy market. However, these renewable energy sources have the characteristics of volatility, randomness, and unpredictability, making it difficult to meet the stable energy demand of residential users. Therefore, there is an urgent need for an efficient energy storage technology to regulate the intermittency of clean energy and ensure stable power supply.

[0003] Compressed air energy storage (CAES) is a potential energy storage technology that has received extensive attention globally in recent years. CAES stores compressed air when the power supply is in excess and generates electricity by releasing the compressed air when the power is insufficient, enabling it to balance the supply and demand fluctuations and providing reliable backup support for intermittent renewable energy. The CAES technology has become one of the only two commercially available large-scale energy storage technologies globally and has been proven to be an effective solution to alleviate the power supply imbalance problem during the utilization of clean energy.

[0004] Currently, there are many types of storage media used in underground compressed air energy storage technology, such as salt caverns, depleted oil and gas reservoirs, or underground caves, etc. There are relevant literature disclosures on compressed air energy storage in the above storage media or other media, but there is no relevant technical literature disclosure on the air compression energy storage technology using underground aquifers. Summary of the Invention

[0005] Aiming at the deficiencies of the above-mentioned prior art, the purpose of the present invention is to provide a compressed air energy storage system using an underground aquifer and a working method thereof, so as to solve the limitation problem of geological compressed air energy storage in rock caves or salt cavities in the prior art. The present invention improves the operating efficiency of the air compression system by maintaining the isothermal characteristics during the system operation process and controlling the heat dissipation of the system.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] A compressed air energy storage system using an underground aquifer according to the present invention includes: an air compression unit, an air expansion unit, a heat storage and circulation unit, and an air injection unit, wherein;

[0008] An air compression unit, comprising an air compression energy storage turbine, a compression-side heat exchange device, and a compressed air temporary storage device connected in sequence; wherein, the air outlet end of the air compression energy storage turbine is connected to the air inlet end of the compression-side heat exchange device, and the air outlet end of the compression-side heat exchange device is connected to the air inlet end of the compressed air temporary storage device;

[0009] An air expansion unit, comprising an air expansion energy release turbine, an expansion-side heat exchange device, and an expanded air temporary storage device connected in sequence; wherein, the air inlet end of the air expansion energy release turbine is connected to the air outlet end of the expansion-side heat exchange device, and the air inlet end of the expansion-side heat exchange device is connected to the air outlet end of the expanded air temporary storage device;

[0010] A heat storage and circulation unit, comprising a high-temperature oil storage tank, a first heat storage oil circulation pump, a low-temperature oil storage tank, and a second heat storage oil circulation pump; wherein, the outlet end of the low-temperature oil storage tank is connected to the heat storage oil inlet end of the compression-side heat exchange device, and the inlet end of the low-temperature oil storage tank is connected to the outlet end of the expansion-side heat exchange device; the inlet end of the high-temperature oil storage tank is connected to the heat storage oil outlet end of the compression-side heat exchange device, and the outlet end of the high-temperature oil storage tank is connected to the inlet end of the expansion-side heat exchange device; the first heat storage oil circulation pump is located on the pipeline between the high-temperature oil storage tank and the expansion-side heat exchange device, and is used to provide the power for the heat storage oil circulation, so that the heat storage oil can flow in the pipeline at a certain flow rate; the second heat storage oil circulation pump is located on the pipeline between the low-temperature oil storage tank and the compression-side heat exchange device, and is used to provide the power for the heat storage oil circulation, so that the heat storage oil can flow in the pipeline at a certain flow rate;

[0011] An air injection unit, comprising a gas injection pipeline, the upper end of which is respectively connected to the air outlet end of the compressed air temporary storage device and the air inlet end of the expanded air temporary storage device, and the lower end of which is connected to a gas storage airbag.

[0012] Further, the air compression unit further includes: a first compression-side valve, the first compression-side valve is arranged between the compression-side heat exchange device and the compressed air temporary storage device, and the air compression energy storage turbine, the compression-side heat exchange device, and the compressed air temporary storage device are connected in sequence through pipelines.

[0013] Further, the air expansion unit further includes: a first expansion-side valve, the first expansion-side valve is arranged between the expansion-side heat exchange device and the expanded air temporary storage device, and the air expansion energy release turbine, the expansion-side heat exchange device, and the expanded air temporary storage device are connected in sequence through pipelines.

[0014] Further, the air injection unit further includes: a second compression-side valve, an injection control valve, a second expansion-side valve, and a three-way pipeline;

[0015] The three-way pipe is used to connect the gas injection pipe, the compressed air storage device, and the expanded air storage device;

[0016] The second valve on the compression side is arranged between the compressed air storage device and the three-way pipe;

[0017] The injection control valve is arranged between the gas injection pipe and the three-way pipe;

[0018] The second valve on the expansion side is arranged between the expanded air storage device and the three-way pipe.

[0019] Further, the heat storage and circulation unit further includes: a first stored hot oil circulation valve and a second stored hot oil circulation valve. The first stored hot oil circulation valve is arranged between the expansion-side heat exchange device and the first stored hot oil circulation pump; the second stored hot oil circulation valve is arranged between the low-temperature oil storage tank and the second stored hot oil circulation pump.

[0020] The present invention also provides a working method of a compressed air energy storage system using an underground aquifer. Based on the above system, the method includes an energy storage process and an energy release process, as follows:

[0021] Energy storage process: The air compression energy storage turbine compresses the air in the atmosphere and transports it through a pipeline to the compression-side heat exchange device. The air fully exchanges heat with the stored hot oil in the compression-side heat exchange device in the compression-side heat exchange device. The cooled compressed air in the compression-side heat exchange device is transported through a pipeline and stored in the compressed air storage device. After the pressure of the compressed air in the compressed air storage device is stable, it is injected into the underground aquifer through the gas injection pipe;

[0022] During the process of the air exchanging heat with the stored hot oil in the compression-side heat exchange device in the compression-side heat exchange device, the stored hot oil in the low-temperature oil storage tank is pumped to the compression-side heat exchange device by the second stored hot oil circulation pump. After the temperature exchange between the compressed air and the stored hot oil in the compression-side heat exchange device is complete, the low-temperature stored hot oil in the low-temperature oil storage tank is pumped to the compression-side heat exchange device. The stored hot oil with an increased oil temperature in the compression-side heat exchange device is pressed into the high-temperature oil storage tank;

[0023] Energy release process: The high-pressure air in the gas storage balloon is injected into the expanded air storage device through the gas injection pipe. The air is transported through a pipeline to the expansion-side heat exchange device to exchange heat with the stored hot oil in the expansion-side heat exchange device. The heated air enters the air expansion energy release turbine through a pipeline, converting the energy in the compressed air into electric energy;

[0024] During the process of heat exchange between the air of the expansion-side heat exchange device and the stored hot oil in the expansion-side heat exchange device, the stored hot oil in the high-temperature oil storage tank is pumped into the expansion-side heat exchange device by the first stored hot oil circulation pump. After the temperature exchange between the compressed air and the stored hot oil in the expansion-side heat exchange device is complete, the high-temperature stored hot oil in the high-temperature oil storage tank is pumped into the expansion-side heat exchange device, and the stored hot oil with reduced oil temperature in the expansion-side heat exchange device is pressed into the low-temperature oil storage tank.

[0025] Advantages of the present invention:

[0026] The present invention utilizes the widely distributed underground aquifers as gas storage reservoirs for energy storage. The compressed air is injected into the aquifers through the air injection system to form gas storage air bags therein, reducing the limitations of the energy storage system on geological conditions and making the development cost of the project more economical.

[0027] The present invention utilizes high-temperature hot oil with a relatively large specific heat capacity to enhance the heat exchange of compressed air, assist the air compression and expansion system, maintain the isothermal characteristics during the operation of the system, control the heat dissipation of the system, and improve the operation efficiency of the air compression system.

[0028] In the present invention, the thermal energy utilization efficiency is greatly increased, and there is no need to use fossil fuel for supplementary combustion, which is more environmentally friendly and efficient. Brief Description of the Drawings

[0029] Figure 1 It is a structural block diagram of the system of the present invention. Detailed Embodiments

[0030] For the convenience of understanding by those skilled in the art, the present invention will be further described below in conjunction with the embodiments and the drawings. The content mentioned in the embodiments does not limit the present invention.

[0031] Referring to Figure 1 As shown, a compressed air energy storage system using underground aquifers of the present invention includes: an air compression unit, an air expansion unit, a heat storage and circulation unit, and an air injection unit, wherein;

[0032] The air compression unit includes an air compression energy storage turbine 1, a compression-side heat exchange device 2, and a compressed air temporary storage device 4 connected in sequence; wherein, the air outlet end of the air compression energy storage turbine 1 is connected to the air inlet end of the compression-side heat exchange device 2, and the air outlet end of the compression-side heat exchange device 2 is connected to the air inlet end of the compressed air temporary storage device 4;

[0033] Among them, the air compression unit further includes: a first compression-side valve 3, the first compression-side valve 3 is arranged between the compression-side heat exchange device 2 and the compressed air temporary storage device 4, and the air compression energy storage turbine 1, the compression-side heat exchange device 2, and the compressed air temporary storage device 4 are connected in sequence through pipelines.

[0034] An air expansion unit, comprising an air expansion energy release turbine 17, an expansion-side heat exchange device 8, and an expansion air temporary storage device 15 that are connected in sequence; wherein, the intake end of the air expansion energy release turbine 17 is connected to the outlet end of the expansion-side heat exchange device 8, and the intake end of the expansion-side heat exchange device 8 is connected to the outlet end of the expansion air temporary storage device 15;

[0035] Wherein, the air expansion unit further includes: a first expansion-side valve 16, the first expansion-side valve 16 is arranged between the expansion-side heat exchange device 8 and the expansion air temporary storage device 15, and the air expansion energy release turbine 17, the expansion-side heat exchange device 8, and the expansion air temporary storage device 15 are connected in sequence through pipelines.

[0036] A heat storage and circulation unit, comprising a high-temperature oil storage tank 11, a first oil storage and circulation pump 10, a low-temperature oil storage tank 7, and a second oil storage and circulation pump 5; wherein, the outlet end of the low-temperature oil storage tank 7 is connected to the oil storage inlet end of the compression-side heat exchange device 2, and the inlet end of the low-temperature oil storage tank 7 is connected to the outlet end of the expansion-side heat exchange device 8; the inlet end of the high-temperature oil storage tank 11 is connected to the oil storage outlet end of the compression-side heat exchange device 2, and the outlet end of the high-temperature oil storage tank 11 is connected to the inlet end of the expansion-side heat exchange device 8; the first oil storage and circulation pump 10 is located on the pipeline between the high-temperature oil storage tank 11 and the expansion-side heat exchange device 8, and is used to provide the power for the oil storage circulation, so that the oil storage can flow in the pipeline at a certain flow rate; the second oil storage and circulation pump 5 is located on the pipeline between the low-temperature oil storage tank 7 and the compression-side heat exchange device 2, and is used to provide the power for the oil storage circulation, so that the oil storage can flow in the pipeline at a certain flow rate;

[0037] Wherein, the heat storage and circulation unit further includes: a first oil storage and circulation valve 9 and a second oil storage and circulation valve 6, the first oil storage and circulation valve 9 is arranged between the expansion-side heat exchange device 8 and the first oil storage and circulation pump 10; the second oil storage and circulation valve 6 is arranged between the low-temperature oil storage tank 7 and the second oil storage and circulation pump 5.

[0038] An air injection unit, comprising a gas injection pipeline 19, the upper end of which is respectively connected to the outlet end of the compressed air temporary storage device 4 and the intake end of the expansion air temporary storage device 15, and the lower end is connected to a gas storage balloon 20;

[0039] Wherein, the air injection unit further includes: a second compression-side valve 12, an injection control valve 13, a second expansion-side valve 14, and a three-way pipeline 18;

[0040] The three-way pipeline 18 is used to connect the gas injection pipeline 19, the compressed air temporary storage device 4, and the expansion air temporary storage device 15;

[0041] The second valve 12 on the compression side is arranged between the compressed air temporary storage device 4 and the three-way pipeline 18;

[0042] The injection control valve 13 is arranged between the gas injection pipeline 19 and the three-way pipeline 18;

[0043] The second valve 14 on the expansion side is arranged between the expanded air temporary storage device 15 and the three-way pipeline 18.

[0044] The present invention also provides a working method of a compressed air energy storage system using an underground aquifer. Based on the above system, it includes an energy storage process and an energy release process, as follows:

[0045] Energy storage process: The air compression energy storage turbine compresses the air in the atmosphere and transports it through a pipeline to the compression side heat exchange device. The air fully exchanges heat with the stored hot oil in the compression side heat exchange device. The cooled compressed air in the compression side heat exchange device is transported through a pipeline and stored in the compressed air temporary storage device. After the pressure of the compressed air in the compressed air temporary storage device is stable, it is injected into the underground aquifer through the gas injection pipeline;

[0046] During the process of the air exchanging heat with the stored hot oil in the compression side heat exchange device, the stored hot oil in the low-temperature oil storage tank is pumped to the compression side heat exchange device by the second stored hot oil circulation pump. After the temperature exchange between the compressed air and the stored hot oil in the compression side heat exchange device is complete, the low-temperature stored hot oil in the low-temperature oil storage tank is pumped to the compression side heat exchange device, and the stored hot oil with an increased oil temperature in the compression side heat exchange device is pressed into the high-temperature oil storage tank; When it is necessary to store excess electric energy during the low electricity consumption period, the energy storage mode is used;

[0047] Energy release process: The high-pressure air in the gas storage airbag is injected into the expanded air temporary storage device through the gas injection pipeline. The air is transported through a pipeline to the expansion side heat exchange device to exchange heat with the stored hot oil in the expansion side heat exchange device. The heated air enters the air expansion energy release turbine through a pipeline to convert the energy in the compressed air into electric energy;

[0048] During the process of the air in the expansion side heat exchange device exchanging heat with the stored hot oil in the expansion side heat exchange device, the stored hot oil in the high-temperature oil storage tank is pumped to the expansion side heat exchange device by the first stored hot oil circulation pump. After the temperature exchange between the compressed air and the stored hot oil in the expansion side heat exchange device is complete, the high-temperature stored hot oil in the high-temperature oil storage tank is pumped to the expansion side heat exchange device, and the stored hot oil with a decreased oil temperature in the expansion side heat exchange device is pressed into the low-temperature oil storage tank; When it is necessary to release excess electric energy during the high electricity consumption period, the energy release mode is used.

[0049] The gas injection pipeline 19 of the air injection unit of the compressed air energy storage system using an underground aquifer is placed into the underground aquifer. By injecting a large amount of air into the aquifer, the original water in the aquifer is displaced, and a gas storage balloon 20 is formed in the underground aquifer.

[0050] Among them, the underground aquifer includes: an upper overburden layer 21, a target reservoir layer 22, and a lower confined layer 23; the upper overburden layer 21 is arranged above the target reservoir layer 22, and the lower confined layer 23 is arranged below the target reservoir layer 22; the gas storage balloon 20 is arranged in the target reservoir layer 22.

[0051] During the energy storage process and the energy release process, air is periodically injected into or withdrawn from the gas storage balloon to meet the power storage and power generation requirements. During operation, it is necessary to maintain the effective volume of the gas storage balloon to maintain the storage space and prevent the water displaced during the air extraction process from returning to the expansion air storage tank.

[0052] The specific application ways of the present invention are numerous. The above description is only the preferred implementation manner of the present invention. It should be pointed out that for those of ordinary skill in the art of this technology, without departing from the principle of the present invention, several improvements can still be made, and these improvements should also be regarded as the protection scope of the present invention.

Claims

1. A compressed air energy storage system utilizing underground aquifers, characterized in that: include: Air compression unit, air expansion unit, heat storage and circulation unit and air injection unit; The air compression unit comprises an air compression energy storage turbine, a compression side heat exchange device and a compressed air temporary storage device connected in sequence; the air outlet end of the air compression energy storage turbine is connected to the air inlet end of the compression side heat exchange device, and the air outlet end of the compression side heat exchange device is connected to the air inlet end of the compressed air temporary storage device; The air expansion unit comprises an air expansion energy-releasing turbine, an expansion-side heat exchange device and an expansion air temporary storage device connected in sequence; the air inlet end of the air expansion energy-releasing turbine is connected to the air outlet end of the expansion-side heat exchange device, and the air inlet end of the expansion-side heat exchange device is connected to the air outlet end of the expansion air temporary storage device; The heat storage and circulation unit comprises a high-temperature oil storage tank, a first heat storage oil circulation pump, a low-temperature oil storage tank and a second heat storage oil circulation pump; the outlet end of the low-temperature oil storage tank is connected to the heat storage oil inlet end of the compression side heat exchange device, and the inlet end of the low-temperature oil storage tank is connected to the outlet end of the expansion side heat exchange device; the inlet end of the high-temperature oil storage tank is connected to the heat storage oil outlet end of the compression side heat exchange device, and the outlet end of the high-temperature oil storage tank is connected to the inlet end of the expansion side heat exchange device; the first heat storage oil circulation pump is located on the pipeline between the high-temperature oil storage tank and the expansion side heat exchange device, and is used to provide heat storage oil circulation power so that the heat storage oil can flow in the pipeline at a certain flow rate; the second heat storage oil circulation pump is located on the pipeline between the low-temperature oil storage tank and the compression side heat exchange device, and is used to provide heat storage oil circulation power so that the heat storage oil can flow in the pipeline at a certain flow rate; The air injection unit comprises a gas injection pipeline, the upper end of which is respectively connected to the air outlet end of the compressed air temporary storage device and the air inlet end of the expanded air temporary storage device, and the lower end is connected to the air storage bag.

2. The compressed air energy storage system using underground aquifers according to claim 1, characterized in that: The air compression unit further includes: a first compression side valve, which is arranged between the compression side heat exchange device and the compressed air temporary storage device. The air compression energy storage turbine, the compression side heat exchange device and the compressed air temporary storage device are connected in sequence through pipelines.

3. The compressed air energy storage system using underground aquifers according to claim 1, characterized in that: The air expansion unit also includes: a first valve on the expansion side, which is arranged between the expansion side heat exchange device and the expansion air temporary storage device. The air expansion energy release turbine, the expansion side heat exchange device and the expansion air temporary storage device are connected in sequence through pipelines.

4. The compressed air energy storage system using underground aquifers according to claim 1, characterized in that: The air injection unit further comprises: a second valve on the compression side, an injection control valve, a second valve on the expansion side and a three-way pipeline; The three-way pipeline is used to connect the gas injection pipeline, the compressed air temporary storage device and the expanded air temporary storage device; The second valve on the compression side is arranged between the compressed air temporary storage device and the three-way pipeline; The injection control valve is arranged between the gas injection pipeline and the three-way pipeline; The second valve on the expansion side is arranged between the expansion air temporary storage device and the three-way pipeline.

5. The compressed air energy storage system using underground aquifers according to claim 1, characterized in that: The heat storage and circulation unit also includes: a first heat storage oil circulation valve and a second heat storage oil circulation valve, wherein the first heat storage oil circulation valve is arranged between the expansion side heat exchange device and the first heat storage oil circulation pump; the second heat storage oil circulation valve is arranged between the low-temperature oil storage tank and the second heat storage oil circulation pump.

6. A method for operating a compressed air energy storage system using an underground aquifer, based on the system according to any one of claims 1 to 5, characterized in that: The method includes an energy storage process and an energy release process, as follows: Energy storage process: The air compression energy storage turbine compresses the air in the atmosphere and transports it to the compression side heat exchange device through a pipeline. The air fully exchanges heat with the heat storage oil in the compression side heat exchange device in the compression side heat exchange device. The compressed air cooled in the compression side heat exchange device is transported through a pipeline and stored in a compressed air temporary storage device. After the compressed air pressure in the compressed air temporary storage device is stabilized, it is injected into the underground aquifer through a gas injection pipeline. During the process of air exchanging heat with the heat storage oil in the compression side heat exchange device in the compression side heat exchange device, the heat storage oil in the low temperature oil storage tank is pumped into the compression side heat exchange device through the second heat storage oil circulation pump. After the compressed air in the compression side heat exchange device and the heat storage oil are completely exchanged in temperature, the low temperature heat storage oil in the low temperature oil storage tank is pumped into the compression side heat exchange device, and the heat storage oil with increased oil temperature in the compression side heat exchange device is pressed into the high temperature oil storage tank. Energy release process: The high-pressure air in the air storage bag is injected into the expansion air temporary storage device through the gas injection pipeline. The air is transported to the expansion side heat exchange device through the pipeline to exchange heat with the heat storage oil in the expansion side heat exchange device. The heated air enters the air expansion energy release turbine through the pipeline to convert the energy in the compressed air into electrical energy. During the process of heat exchange between the air of the expansion side heat exchange device and the heat storage oil in the expansion side heat exchange device, the heat storage oil in the high-temperature oil storage tank is pumped into the expansion side heat exchange device through the first heat storage oil circulation pump. After the compressed air in the expansion side heat exchange device and the heat storage oil are completely exchanged in temperature, the high-temperature heat storage oil in the high-temperature oil storage tank is pumped into the expansion side heat exchange device, and the heat storage oil with reduced oil temperature in the expansion side heat exchange device is pressed into the low-temperature oil storage tank.

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