A compressed air energy storage system with partial pressure operation

Abstract

The present invention provides a partial pressure operation compressed air energy storage system, which belongs to the technical field of compressed air energy storage, and comprises: a first air storage chamber and a second air storage chamber with a pressure level greater than that of the first air storage chamber; a first compression unit, which is connected to the first air storage chamber through a cold storage heat exchanger; a second compression unit, which is connected to the second air storage chamber; the power consumption of the first compression unit is less than the power consumption of the second compression unit; during energy storage, when the power provided by renewable energy is low, the air is compressed by the first compression unit, enters the cold storage heat exchanger and is converted into liquid, and then stored in the first air storage chamber in liquid state; when the power provided by renewable energy is high, the air is compressed by the second compression unit, and directly enters the second air storage chamber for storage. Thus, the fluctuation of renewable energy is adapted, and compressed air energy is stored by partial pressure.

Description

Technical Field

[0001] The present invention relates to the technical field of compressed air energy storage, and in particular to a partial pressure operation compressed air energy storage system. Background Art

[0002] In my country, both wind and solar energy resources are relatively abundant, but the intermittent and volatile nature of renewable energy hinders its development.

[0003] Compressed air energy storage, as a large-scale energy storage technology with great potential, can effectively curb the instability of renewable energy.

[0004] However, the current compressed air energy storage technology has a limited range of operating conditions and cannot adapt to the volatility of renewable energy. Summary of the invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the defect that the compressed air energy storage system in the prior art cannot adapt to the volatility of renewable energy, thereby providing a partial pressure operation compressed air energy storage system.

[0006] In order to solve the above technical problems, the present invention provides a partial pressure operation compressed air energy storage system, comprising: a first air storage chamber and a second air storage chamber with a pressure level greater than that of the first air storage chamber;

[0007] a first compression unit, connected to the first air storage chamber via a cold storage heat exchanger, the first compression unit being used to charge liquid compressed air into the first air storage chamber;

[0008] a second compression unit, connected to the second air storage chamber, and configured to charge compressed air into the second air storage chamber;

[0009] The power consumption of the first compression unit is less than the power consumption of the second compression unit.

[0010] Optionally, the first compression unit comprises: a first compressor and a second compressor connected in series.

[0011] Optionally, the second compression unit comprises: a third compressor connected in series with the first compression unit.

[0012] Optionally, outlets of the first compressor, the second compressor and the third compressor are respectively connected to aftercoolers.

[0013] Optionally, the cold storage heat exchanger is connected to the first air storage chamber via a pressure reducing device.

[0014] Optionally, the pressure reduction device includes: a liquid expander.

[0015] Optionally, it also includes:

[0016] a first expansion unit, connected to the first air storage chamber;

[0017] a second expansion unit, connected to the second air storage chamber;

[0018] An expansion ratio of the first expansion unit is smaller than an expansion ratio of the second expansion unit.

[0019] Optionally, the first expansion unit comprises: a first expander and a second expander connected in series.

[0020] Optionally, the second expansion unit comprises: a third expander connected in series with the first expansion unit.

[0021] Optionally, the inlets of the first expander, the second expander and the third expander are respectively connected to reheaters.

[0022] The technical solution of the present invention has the following advantages:

[0023] The partial pressure operation compressed air energy storage system provided by the present invention stores energy. When the power provided by renewable energy is low, the air is compressed by the first compression unit, enters the cold storage heat exchanger to be converted into liquid, and then stored in the first air storage chamber in liquid state; when the power provided by renewable energy is high, the air is compressed by the second compression unit, and directly enters the second air storage chamber for storage. This adapts to the volatility of renewable energy and stores compressed air energy at partial pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 This is a schematic diagram of an implementation of a partial pressure operation compressed air energy storage system provided in an embodiment of the present invention.

[0026] Description of reference numerals:

[0027] 1. First air storage chamber; 2. Second air storage chamber; 3. First compressor; 4. Second compressor; 5. Third compressor; 6. Aftercooler; 7. Cold storage heat exchanger; 8. Pressure reduction device; 9. Low temperature pump; 10. First expander; 11. Second expander; 12. Third expander; 13. Reheater; 14. Regenerator; 15. Solar thermal collector; 16. Heat storage device. DETAILED DESCRIPTION

[0028] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0030] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0031] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0032] The partial pressure operation compressed air energy storage system provided in this embodiment can be used to store energy in conjunction with renewable energy to eliminate the intermittent defects of renewable energy. By adopting the partial pressure operation mode, the volatility of renewable energy can be adapted.

[0033] like Figure 1As shown, a specific implementation of the partial pressure operation compressed air energy storage system provided in this embodiment includes: a first air storage chamber 1 and a second air storage chamber 2, wherein the pressure level of the second air storage chamber 2 is greater than the pressure level of the first air storage chamber 1. The first compression unit is connected to the first air storage chamber 1 through the cold storage heat exchanger 7, and the first compression unit is used to fill liquid compressed air into the first air storage chamber 1; the second compression unit is connected to the second air storage chamber 2, and the second compression unit is used to fill compressed air into the second air storage chamber 2; and the power consumption of the first compression unit is less than the power consumption of the second compression unit. Among them, the second air storage chamber 2 can be a constant volume device such as an underground cave, a gas storage tank, a gas storage pipeline, or a constant pressure device such as an underwater air bag.

[0034] During energy storage, when the power provided by renewable energy is low, the air is compressed by the first compression unit, enters the cold storage heat exchanger 7 and is converted into liquid, and then stored in the first air storage chamber 1 in liquid state; when the power provided by renewable energy is high, the air is compressed by the second compression unit and directly enters the second air storage chamber 2 for storage. This adapts to the volatility of renewable energy and stores compressed air energy at a divided pressure.

[0035] like Figure 1 As shown, in the partial pressure operation compressed air energy storage system provided in this embodiment, the first compression unit includes: a first compressor 3 and a second compressor 4 connected in series. The outlets of the first compressor 3 and the second compressor 4 are respectively connected to an aftercooler 6, and the compression process of the compressor is made nearly isothermal compression by the aftercooler 6, thereby avoiding excessively high temperature of the compressed gas.

[0036] like Figure 1 As shown, the second compression unit includes: a third compressor 5 connected in series with the first compression unit. That is to say, the second compression unit includes the first compressor 3, the second compressor 4 and the third compressor 5 connected in series. Therefore, the power consumed by the second compression unit is relatively large. The outlets of the third compressor 5 are respectively connected to aftercoolers 6. The compression process of the compressor is made nearly isothermal compression by the aftercoolers 6, thereby avoiding excessively high temperature of the compressed gas.

[0037] like Figure 1 As shown, in the partial pressure operation compressed air energy storage system provided in this embodiment, the cold storage heat exchanger 7 is connected to the first air storage chamber 1 through a pressure reducing device 8. Specifically, the pressure reducing device 8 can be: a liquid expander or other pressure reducing device 8, such as a throttle valve, etc. The pressure in the first air storage chamber 1 can be appropriately reduced by the pressure reducing device 8, and its heat can be increased for better storage. The outlet of the first air storage chamber 1 is connected to the second medium flow channel of the cold storage heat exchanger 7 through a low-temperature pump 9, and enters the expansion unit to perform work after passing through the cold storage heat exchanger 7.

[0038] like Figure 1 As shown, the partial pressure operation compressed air energy storage system provided in this embodiment also includes: an expansion unit, which is used to release the energy of the air storage chamber. Specifically, the expansion unit includes: a first expansion unit and a second expansion unit, wherein the first expansion unit is connected to the first air storage chamber 1, and the second expansion unit is connected to the second air storage chamber 2; and the expansion ratio of the first expansion unit is less than the expansion ratio of the second expansion unit. Thus, the compression energy in the first air storage chamber 1 and the second air storage chamber 2 can be fully utilized.

[0039] like Figure 1 As shown, the first expansion unit includes: a first expander 10 and a second expander 11 connected in series, and the inlets of the first expander 10 and the second expander 11 are respectively connected to a reheater 13, and the reheater 13 is used to increase the temperature of the compressed gas, so that the compressed gas energy can be better utilized to do work.

[0040] like Figure 1 As shown, the second expansion unit includes: a third expansion machine 12 connected in series with the first expansion unit. That is to say, the second expansion unit includes a first expansion machine 10, a second expansion machine 11 and a third expansion machine 12 connected in series. Therefore, the expansion ratio of the second expansion unit is greater than that of the first expansion unit. The inlet of the third expansion machine 12 is connected to a reheater 13, which is used to increase the temperature of the compressed gas, so that the compressed gas energy can be better utilized to do work.

[0041] like Figure 1 As shown, the partial pressure operation compressed air energy storage system provided in this embodiment also includes: a solar thermal collector 15, the solar thermal collector 15 is connected to the reheater 13, so as to use solar energy to heat the compressed gas in the energy release process. In addition, in order to overcome the intermittent problem of the solar thermal collector 15, a heat storage device 16 is connected to the outlet of the solar thermal collector 15, and the outlet of the heat storage device 16 is connected to the reheater 13. Thus, the energy of the solar thermal collector 15 is collected by the heat storage device 16, and when the energy release changes, it can be adjusted by adjusting the solar energy input heat. Among them, the solar thermal collector 15 can directly input heat to the reheater 13, or it can be operated in conjunction with the heat storage device 16. The heat storage device 16 can be sensible heat storage, phase change heat storage, thermochemical heat storage, etc. Specifically, it can be packed bed heat storage, or double tank indirect heat storage, etc. The heat source of the heat storage device 16 can also come from other external heat sources, such as electric heating.

[0042] like Figure 1As shown, in the partial pressure operation compressed air energy storage system provided in this embodiment, the expansion unit is connected to the first air storage chamber 1 through the regenerator 14, and the second channel of the regenerator 14 is connected to the outlet of the third expander 12. Thus, the high-temperature gas that has released energy is fully utilized to heat the compressed gas entering the expansion unit, thereby improving the utilization effect of the compressed gas.

[0043] It should be noted that the number of compressors in the compression unit provided in this embodiment is not limited to three, and the number of expanders in the expansion unit is not limited to three. At the same time, the number of compressors and the number of expanders may not be equal.

[0044] Obviously, the above embodiments are merely examples for clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the scope of protection of the present invention.

Claims

1. A partial pressure operation compressed air energy storage system, characterized in that: include: A first air storage chamber (1) and a second air storage chamber (2) having a pressure level greater than that of the first air storage chamber (1); a first compression unit, connected to the first air storage chamber (1) via a cold storage heat exchanger (7), the first compression unit being used to charge liquid compressed air into the first air storage chamber (1); a second compression unit, connected to the second air storage chamber (2), the second compression unit being used to fill compressed air into the second air storage chamber (2); The power consumption of the first compression unit is less than the power consumption of the second compression unit.

2. The partial pressure operation compressed air energy storage system according to claim 1 is characterized in that: The first compression unit comprises: a first compressor (3) and a second compressor (4) connected in series.

3. The partial pressure operation compressed air energy storage system according to claim 2 is characterized in that: The second compression unit comprises: a third compressor (5) connected in series with the first compression unit.

4. The partial pressure operation compressed air energy storage system according to claim 3 is characterized in that: The outlets of the first compressor (3), the second compressor (4) and the third compressor (5) are respectively connected to aftercoolers (6).

5. The partial pressure operation compressed air energy storage system according to claim 1, characterized in that: The cold storage heat exchanger (7) is connected to the first air storage chamber (1) via a pressure reducing device (8).

6. The partial pressure operation compressed air energy storage system according to claim 5, characterized in that: The pressure reducing device (8) comprises: a liquid expander.

7. The partial pressure operation compressed air energy storage system according to any one of claims 1 to 6, characterized in that: Also includes: A first expansion unit, connected to the first air storage chamber (1); a second expansion unit, connected to the second air storage chamber (2); An expansion ratio of the first expansion unit is smaller than an expansion ratio of the second expansion unit.

8. The partial pressure operation compressed air energy storage system according to claim 7, characterized in that: The first expansion unit comprises: a first expander (10) and a second expander (11) connected in series.

9. The partial pressure operation compressed air energy storage system according to claim 8, characterized in that: The second expansion unit comprises: a third expansion machine (12) connected in series with the first expansion unit.

10. The partial pressure operation compressed air energy storage system according to claim 9, characterized in that: The inlets of the first expander (10), the second expander (11) and the third expander (12) are respectively connected to a reheater (13).

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