A compressed air energy storage system for filling and laying pipelines in abandoned mines with heat storage at normal temperature and its usage method

Abstract

The present invention discloses a normal-temperature heat storage type compressed air energy storage system for buried pipelines in abandoned mines and a using method thereof. The system includes: a compressed air storage pipeline, a heat storage chamber, a first heat exchange pipeline, a first expander or turbine, a second heat exchange pipeline, and a generator. A cyclic heat exchange is carried out between the compressed air storage pipeline and the heat storage chamber through the first heat exchange pipeline. A cyclic heat exchange is carried out between the heat storage chamber and the compressed air storage pipeline through the second heat exchange pipeline, and two ends of the second heat exchange pipeline are respectively connected to the inlet and outlet of the first expander or turbine. The heat exchange medium in the second heat exchange pipeline is a mixture of propane and butane, which is in a gaseous state at normal temperature. The generator is connected to the first expander or turbine. The above energy storage system can achieve normal-temperature heat storage, thereby reducing heat loss caused by the heat storage chamber being higher than the ambient temperature due to the stored heat and improving the utilization rate of heat.

Description

Technical Field

[0001] The present invention relates to the technical field of mine energy storage, and particularly to a compressed air energy storage system and a usage method thereof for filling and burying pipelines in an abandoned mine with normal temperature heat storage. Background Art

[0002] Although energy sources such as solar energy and wind energy that do not rely on fossil fuels for power generation have the advantages of being cleaner and greener, their power generation is unstable and poorly controllable due to weather changes. Therefore, it is not advisable to directly incorporate the electric energy generated by them into the power grid. Compressed gas energy storage technology provides a good solution to the above problems. That is, even if the redundant electric power is used to compress the gas into a gas storage pipeline, and then released again during the peak electricity consumption period, the compressed potential energy of the air is used for power generation, thereby improving the regulation ability of the power grid. At the same time, compressed air energy storage has technical advantages such as large scale, long-term energy storage, and high safety. Moreover, compared with traditional power generation technologies, compressed air energy storage technology does not produce carbon emissions and solid waste, so it is still a green renewable energy utilization technology.

[0003] During the process of compressing the gas by a compressor, the temperature of the gas will rise above 100°C. Eventually, these heats dissipated from the gas storage pipeline to the outside will cause a large amount of energy waste, which is an important factor leading to the low energy utilization rate of compressed gas energy storage technology. To solve the above problems, heat exchange technology is usually adopted at present to transfer these heats to a heat storage chamber for storage. Then, when releasing compressed air for power generation, these heats are used to reheat the compressed air to increase its power generation. However, this method also has problems such as heat loss caused by the gradual heat dissipation of the heat storage chamber and low heat exchange rate. Moreover, the longer the storage time, the greater the loss and the lower the heat utilization rate. Summary of the Invention

[0004] In view of the above problems, the present invention provides a compressed air energy storage system and a usage method thereof for filling and burying pipelines in an abandoned mine with normal temperature heat storage. This system can achieve normal temperature heat storage, thereby reducing the heat loss caused by the heat storage chamber being higher than the ambient temperature due to the stored heat and improving the heat utilization rate. Specifically, the technical solution of the present invention is as follows.

[0005] First, the present invention discloses a normal-temperature heat storage type compressed air energy storage system for filling and laying pipelines in abandoned mines and its usage method, including: a compressed air storage pipeline, a heat storage chamber, a first heat exchange pipeline, a first expander or turbine, a second heat exchange pipeline, a pump body, and a generator. Among them: A circulating heat exchange is carried out through the connection between the compressed air storage pipeline and the heat storage chamber by the first heat exchange pipeline. The heat storage chamber and the compressed air storage pipeline are connected through the second heat exchange pipeline for circulating heat exchange, and both ends of the second heat exchange pipeline are respectively connected to the inlet and outlet of the first expander or turbine. The heat exchange medium stored in the second heat exchange pipeline is a mixture of propane and butane, which has a low boiling point and is gaseous at normal temperature and turns into a liquid below the boiling point. The pump body is provided on both the first heat exchange pipeline and the second heat exchange pipeline to drive the flow of the heat exchange medium. The generator is connected to the first expander or turbine to drive the generator to generate electricity.

[0006] Further, the compressed air storage pipeline can be laid in the roadway of the abandoned mine to utilize the abandoned mine resourcefully.

[0007] Further, the outside of the compressed air storage pipeline is filled with particulate matter, so as to play a role in heat preservation and reducing heat loss to a certain extent. Optionally, the particulate matter includes at least one of slag, steel slag, recycled concrete aggregate, etc.

[0008] Further, the boiling point range of the propane and butane is controlled between -10 and -1 °C.

[0009] Further, the outer walls of the part of the first heat exchange pipeline located outside the compressed air storage pipeline and the heat storage chamber and the outer wall of the heat storage chamber are all coated with a heat insulation layer to reduce heat dissipation. Optionally, the material of the heat insulation layer includes any one of rock wool, polyurethane foam material, etc.

[0010] Further, the exhaust port of the compressed air storage pipeline, the second expander or turbine, and the generator are connected in sequence.

[0011] Further, the inlet of the compressed air storage pipeline is connected to a gas compressor.

[0012] Further, the gas compressor is connected to an electric motor to drive the gas compressor to compress gas.

[0013] Optionally, the connection form between the first heat exchange pipeline and the compressed air storage pipeline is that the first heat exchange pipeline is wound around the compressed air storage pipeline to facilitate heat exchange between the two.

[0014] Optionally, the connection form between the first heat exchange pipeline and the heat storage chamber is that the first heat exchange pipeline passes through the liquid heat exchange medium in the heat storage chamber, so as to conduct heat exchange between the two.

[0015] Optionally, any one of water, heat-conducting oil, etc. is included in the heat storage medium and the liquid heat exchange medium in the first heat exchange pipeline in the heat storage chamber.

[0016] Secondly, the present invention discloses a method for using the regenerative waste mine filling pipeline compressed air energy storage system, including the following steps:

[0017] (1) In the stage of filling compressed air into the compressed air storage pipeline, start the circulation of the liquid heat exchange medium in the first heat exchange pipeline, and transfer the heat in the compressed air to the heat storage medium in the heat storage chamber. During this process, do not start the flow of the heat exchange medium in the second heat exchange pipeline.

[0018] (2) In the stage of the compressed air storage pipeline releasing compressed air to generate electricity, start the flow of the liquid heat exchange medium in the first heat exchange pipeline and the heat exchange medium in the second heat exchange pipeline at the same time. During this process, the compressed air storage pipeline heats the compressed air through heat exchange with the heat storage chamber to increase the power generation. The gaseous heat exchange medium in the second heat exchange pipeline does work through the first expander or turbine, and the first expander or turbine drives the generator to generate electricity. Then, heat exchange is carried out through the compressed air storage pipeline to heat the compressed air therein. Then the heat exchange medium in the second heat exchange pipeline turns into a liquid, continues to flow through the heat storage chamber and is heated to become gaseous again, and then enters the first expander or turbine again to repeat the above process, realizing the efficient utilization of the heat in the heat storage chamber.

[0019] Compared with the prior art, the present invention has at least the following beneficial technical effects:

[0020] The compressed air energy storage system of the present invention realizes heat storage at normal temperature, thereby reducing heat loss caused by the heat stored in the heat storage chamber being higher than the ambient temperature, and improving the utilization rate of heat. This is because: when transferring the heat energy generated during the stage of filling compressed air into the compressed air storage pipeline to the heat storage chamber for storage, the problem of heat loss will inevitably occur. Especially as the storage time increases, the retained heat will become less and less. In this case, during the stage of the compressed air storage pipeline releasing compressed air for power generation, the traditional method of directly heating the compressed air storage pipeline by using the water in the heat exchange pipeline as the heat exchange medium with the residual heat in the heat storage chamber obviously has problems of low heat exchange efficiency and low heat utilization rate, resulting in the inability to heat the gas in the compressed air storage pipeline in a timely manner and the inability to fully utilize the heat in the heat storage chamber. Therefore, the present invention provides a second heat exchange pipeline with a mixture of propane and butane as the heat exchange medium and a first expander or turbine, and connects the heat storage chamber and the compressed air storage pipeline through the second heat exchange pipeline for cyclic heat exchange, and at the same time connects both ends of the second heat exchange pipeline to the inlet and outlet of the first expander or turbine respectively.

[0021] Through the cooperation between the heat exchange route of the compressed air storage pipeline and the heat storage chamber through the first heat exchange pipeline and another heat exchange route of the compressed air storage pipeline and the heat storage chamber through the first expander or turbine and the second heat exchange pipeline, not only can the energy in the heat storage chamber be fully utilized, and it can still be utilized even when the temperature in the heat storage chamber has dropped to room temperature. Moreover, it also realizes the reverse absorption and utilization of the energy in the environment, which is equivalent to indirectly reducing the heat loss caused by the heat storage chamber dissipating heat to the environment during the heat storage process. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The specification drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0023] Figure 1 It is a schematic structural diagram of a heat storage type waste mine filling and laying pipeline compressed air energy storage system in the following embodiments. Among them, the reference numerals respectively represent: 1 - compressed air storage pipeline, 2 - heat storage chamber, 3 - first heat exchange pipeline, 4 - first expander or turbine, 5 - second heat exchange pipeline, 6 - pump body, 7 - generator, 8 - second expander or turbine, 9 - gas compressor, 10 - motor. DETAILED DESCRIPTION OF THE INVENTION

[0024] It should be noted that the following detailed description is illustrative and aims to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention pertains.

[0025] For the convenience of description, if terms such as "upper", "lower", "left", and "right" appear in the present invention, they only represent the same directions as the upper, lower, left, and right of the accompanying drawings themselves, and do not limit the structure. They are only for facilitating the description of the present invention and simplifying the description, rather than indicating or implying that the device or element referred to needs to have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention.

[0026] Now, in combination with the accompanying drawings of the specification and specific embodiments, a compressed air energy storage system and its usage method for a normal temperature heat storage type buried pipeline in an abandoned mine are further described.

[0027] Reference Figure 1 , an example of a heat storage type compressed air energy storage system for buried pipelines in an abandoned mine is shown, including: a compressed air storage pipeline 1, a heat storage chamber 2, and a first heat exchange pipeline 3. Specifically: The compressed air storage pipeline 1 is laid in the roadway of the abandoned mine to utilize the abandoned mine resourcefully. The heat storage chamber 2 is arranged on one side of the compressed air storage pipeline 1, and the first heat exchange pipeline 3 is wound around the outer wall of the compressed air storage pipeline 1 to facilitate heat exchange between the two, and other any suitable heat exchange forms can also be adopted. At the same time, the first heat exchange pipeline 3 passes through the liquid heat exchange medium in the heat storage chamber 2, thereby forming a first loop heat exchange system between the compressed air storage pipeline 1 and the heat storage chamber 2. When in use, the liquid heat exchange medium in the heat storage chamber 2 and the first heat exchange pipeline 3 can be selected from water, heat-conducting oil, etc. At the same time, in order to drive the circulating flow of the liquid heat exchange medium in the first heat exchange pipeline 3, a pump body 6 is arranged on the first heat exchange pipeline 3.

[0028] Furthermore, the energy storage system further includes a first expander or turbine 4, a second heat exchange pipeline 5, a pump body 6, and a generator 7. Specifically, the second heat exchange pipeline 5 is wound around the outer wall of the compressed air storage pipeline 1 to facilitate heat exchange between the two, and other any suitable heat exchange forms can also be adopted. At the same time, the second heat exchange pipeline 5 passes through the liquid heat exchange medium in the heat storage chamber 2, and both ends of the second heat exchange pipeline 5 are respectively connected to the inlet and outlet of the first expander or turbine 4, thereby forming a second loop heat exchange system between the compressed air storage pipeline 1 and the heat storage chamber 2.

[0029] In this embodiment, the heat exchange medium stored in the second heat exchange pipe 5 is a mixture of propane and butane. For example, when the boiling points of propane and butane are between -10°C and -1°C (such as -10°C, -5°C, -1°C, etc.), this heat exchange medium is gaseous at room temperature and turns into a liquid below the boiling point, so that the heat exchange medium can also perform heat exchange above 0°C. A pump body 6 is also provided on the second heat exchange pipe 5 to drive the flow of the heat exchange medium in the second heat exchange pipe 5. The first expander or turbine 4 is connected to the generator 7 to drive the generator 7 to generate electricity.

[0030] In another embodiment, with continued reference to Figure 1 , the regenerative waste mine landfill pipeline compressed air energy storage system of the above embodiment further includes a second expander or turbine 8. The inlet of the second expander or turbine 8 is communicated with the exhaust port of the compressed air storage pipeline 1, and the outlet of the second expander or turbine 8 is connected to the generator 7, so as to drive the second expander or turbine 8 to rotate by using the compressed gas released from the compressed air storage pipeline 1, and further drive the generator 7 to generate electricity.

[0031] In another embodiment, the regenerative waste mine landfill pipeline compressed air energy storage system of the above embodiment further includes a heat insulation layer. The outer walls of the parts of the first heat exchange pipe 3 outside the compressed air storage pipeline 1 and the heat storage chamber 2 and the outer wall of the heat storage chamber 2 are all coated with a heat insulation layer to reduce heat dissipation. Optionally, the material of the heat insulation layer can be selected from rock wool, polyurethane foam materials, etc.

[0032] In another embodiment, the outside of the compressed air storage pipeline 1 of the regenerative waste mine landfill pipeline compressed air energy storage system of the above embodiment is filled with particulate matter, and the particulate matter can be selected from one or more of slag, steel slag, recycled concrete aggregate, etc., so as to play a certain heat insulation role, help reduce the heat loss of the compressed air in the compressed air storage pipeline 1, and increase the power generation.

[0033] In another embodiment, with continued reference to Figure 1 , the regenerative waste mine landfill pipeline compressed air energy storage system of the above embodiment further includes a gas compressor 9 and a motor 10. Among them: the motor 10 is connected to the gas compressor 9, and the gas compressor 9 is connected to the inlet of the compressed air storage pipeline 1 to fill compressed gas into the compressed air storage pipeline 1.

[0034] During use, (1) in the stage of filling compressed air into the compressed air storage pipeline 1, the temperature of the gas rises rapidly after being compressed (PV = nRT, where P is pressure, V is volume, n is the amount of substance, R is a constant, and T is temperature). Therefore, after starting the pump body 6 on the first heat exchange pipeline 3, the liquid heat exchange medium in the first heat exchange pipeline 3 is driven to circulate. After being heated by the high-temperature gas in the compressed air storage pipeline 1, it becomes a high-temperature heat exchange medium and then enters the heat storage chamber 2 to heat the heat storage medium therein, thereby transferring the heat in the compressed air to the heat storage medium in the heat storage chamber 2. During this process, the flow of the heat exchange medium in the second heat exchange pipeline 5 is not started.

[0035] (2) When the temperature difference between the gas in the compressed air storage pipeline 1 and the heat storage medium in the heat storage chamber 2 approaches zero, the operation of the pump body 6 on the first heat exchange pipeline 3 is stopped, thereby stopping the heat exchange between the compressed air storage pipeline 1 and the heat storage chamber 2. At this time, the heat storage medium in the heat storage chamber 2 is in a high-temperature state. However, as the storage time increases, the problem of heat loss will inevitably occur, resulting in less and less heat retained by the heat storage medium in the heat storage chamber 2. In this case, in the stage of the compressed air storage pipeline 1 releasing compressed air for power generation, when the traditional method is to use the remaining heat in the heat storage chamber 2 and directly heat the compressed air storage pipeline 1 with the heat exchange medium in the first heat exchange pipeline 3, there are obvious problems of low heat exchange efficiency and low heat utilization rate, resulting in the inability to heat the gas in the compressed air storage pipeline 1 in a timely manner and the inability to fully utilize the heat in the heat storage chamber 2.

[0036] In the second-loop cyclic heat exchange system with the above-described embodiment, after using a mixture of propane and butane as the heat exchange medium in the second heat exchange pipe 5 (denoted as propane-butane medium), during the stage when the compressed air storage pipe 1 releases compressed air for power generation, since the liquid propane-butane medium can absorb heat from the environment, the medium remains in a gaseous expansion state at this time. When the pump body 6 on the second heat exchange pipe 5 is started, the gaseous propane-butane medium therein is driven to flow through the first expander or turbine 4 first. At this time, the volume expansion of the propane-butane medium can be used to do work on the first expander or turbine 4, thereby driving the generator 7 to generate electricity, realizing the utilization of the internal energy of the propane-butane medium and also realizing the reverse recovery and utilization of the heat in the environment. Then, when the gaseous propane-butane medium continues to pass through the compressed air storage pipe 1, since the compressed air storage pipe 1 releases gas, its temperature drops below zero (as above, PV = nRT), resulting in a large temperature difference between the propane-butane medium and the compressed air storage pipe 1, thus realizing more rapid and efficient heat exchange between the two, quickly increasing the temperature of the gas in the compressed air storage pipe 1 and improving the power generation efficiency. At this time, after a large amount of heat is released, the temperature of the propane-butane medium drops below the boiling point and becomes liquid. Then, the liquid propane-butane medium exchanges heat with the heat storage chamber 2. At this time, even if the temperature in the heat storage chamber 2 has dropped to room temperature due to heat exchange or long-term heat storage, the liquid propane-butane medium can quickly absorb heat from the heat storage chamber 2 and turn back into gas. Then it re-enters the first expander or turbine 4 to do work. In addition, since the propane-butane medium changes from liquid to gas and continuously absorbs heat from the heat storage chamber 2, the heat storage medium in the heat storage chamber 2 will be in a state lower than normal temperature, which also promotes the reverse absorption and utilization of the energy in the environment by the heat storage medium in the heat storage chamber 2, and during the next cycle of charging compressed air, it fully exchanges heat with the high-temperature gas in the compressed air storage pipe 1 to improve the heat exchange efficiency.

[0037] Through the cooperation between the first-loop cyclic heat exchange system in which the compressed air storage pipe 1 and the heat storage chamber 2 exchange heat through the first heat exchange pipe 3, and the second-loop cyclic heat exchange system in which the compressed air storage pipe 1 and the heat storage chamber 2 exchange heat through the first expander or turbine 4 and the second heat exchange pipe 5, not only can the energy in the heat storage chamber 2 be fully utilized, but also it can be utilized even if the temperature in the heat storage chamber 2 has dropped to room temperature. Moreover, the reverse absorption and utilization of the energy in the environment are realized, which is equivalent to indirectly reducing the heat loss caused by heat dissipation from the heat storage chamber 2 to the environment during the heat storage process. In summary, the compressed air energy storage system of the present invention achieves the purpose of heat storage at normal temperature and can also fully utilize heat, thereby overcoming the problem that the heat in the heat storage chamber cannot be fully utilized due to heat dissipation caused by the heat in the heat storage chamber being higher than the environmental temperature.

[0038] Finally, it should be noted that any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention. Although the specific implementation manners of the present invention have been described above in conjunction with the accompanying drawings, it is not a limitation on the protection scope of the present invention. Those skilled in the art should understand that various modifications or deformations that can be made without creative efforts on the basis of the technical solution of the present invention are still within the protection scope of the present invention.

Claims

1. A normal temperature thermal storage abandoned mine filling buried pipeline compressed air energy storage system, characterized in that: include: A compressed air storage pipeline; the compressed air storage pipeline is arranged in a tunnel of an abandoned mine; A heat storage chamber, wherein the compressed air storage pipeline and the heat storage chamber are connected via a first heat exchange pipeline for cyclic heat exchange; The first expander or turbine, the heat storage chamber and the compressed air storage pipeline are connected through a second heat exchange pipeline for cyclic heat exchange, and the two ends of the second heat exchange pipeline are respectively connected to the inlet and outlet of the first expander or turbine; the heat exchange medium stored in the second heat exchange pipeline is a mixture of propane and butane, which is gaseous at room temperature and changes into liquid when it is below the boiling point; The pump body is provided on the first heat exchange pipe and the second heat exchange pipe; and the outer wall of the first heat exchange pipe located outside the compressed air storage pipe and the heat storage chamber is covered with an insulation layer; the first heat exchange pipe and the compressed air storage pipe are connected in a manner that the first heat exchange pipe is wound around the compressed air storage pipe; the first heat exchange pipe and the heat storage chamber are connected in a manner that the first heat exchange pipe passes through the liquid heat exchange medium in the heat storage chamber; A generator is connected to the first expansion machine or the turbine.

2. The thermal storage abandoned mine filling buried pipeline compressed air energy storage system according to claim 1 is characterized in that: The outside of the compressed air storage pipeline is filled with heat-insulating particles.

3. The thermal storage abandoned mine filling buried pipeline compressed air energy storage system according to claim 2 is characterized in that: The particulate matter includes at least one of slag, steel slag, and recycled concrete aggregate.

4. The thermal storage abandoned mine filling buried pipeline compressed air energy storage system according to claim 1 is characterized in that: The boiling point range of the propane and butane is controlled between -10 and -1°C.

5. The thermal storage abandoned mine filling buried pipeline compressed air energy storage system according to claim 1 is characterized in that: The outer wall of the heat storage chamber is coated with a heat insulation layer.

6. The thermal storage abandoned mine filling buried pipeline compressed air energy storage system according to claim 1 is characterized in that: The material of the thermal insulation layer includes any one of rock wool and polyurethane foam material.

7. The thermal storage abandoned mine filling buried pipeline compressed air energy storage system according to claim 1 is characterized in that: The exhaust port of the compressed air storage pipeline, the second expander or turbine, and the generator are connected in sequence.

8. The thermal storage abandoned mine filling buried pipeline compressed air energy storage system according to claim 1 is characterized in that: The air inlet of the compressed air storage pipeline is connected to the gas compressor.

9. The thermal storage abandoned mine filling buried pipeline compressed air energy storage system according to claim 8 is characterized in that: The gas compressor is connected to the electric motor.

10. The thermal storage abandoned mine filling buried pipeline compressed air energy storage system according to claim 1 is characterized in that: The heat storage medium in the heat storage chamber and the liquid heat exchange medium in the first heat exchange pipe include any one of water and heat transfer oil.

11. The method for using the thermal storage abandoned mine filling and buried pipeline compressed air energy storage system according to any one of claims 1 to 10, characterized in that: The steps include: (1) When the compressed air is charged into the compressed air storage pipeline, the circulation of the liquid heat exchange medium in the first heat exchange pipeline is started to transfer the heat in the compressed air to the heat storage medium in the heat storage chamber; during this process, the flow of the heat exchange medium in the second heat exchange pipeline is not started; (2) During the stage of releasing compressed air from the compressed air storage pipeline to generate electricity, the flow of the liquid heat exchange medium in the first heat exchange pipeline and the heat exchange medium in the second heat exchange pipeline are started at the same time; during this process, the compressed air storage pipeline heats the compressed air by heat exchange with the heat storage chamber; the gaseous heat exchange medium in the second heat exchange pipeline passes through the first expander or turbine to perform work, and the first expander or turbine drives the generator to generate electricity; then the compressed air therein is heated by heat exchange through the compressed air storage pipeline; then the heat exchange medium in the second heat exchange pipeline is converted into liquid, continues to flow through the heat storage chamber, is heated and becomes gaseous again, and then enters the first expander or turbine again to repeat the above process.

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