Expansion section system for compressed air energy storage

Abstract

The utility model provides an expansion section system for compressed air energy storage. The expansion section system at least comprises an expansion pipeline and a heating pipeline. The expansion pipeline comprises gas storage equipment, a first gas-water heat exchanger, a first-stage expansion machine, a second gas-water heat exchanger, a second-stage expansion machine, a third gas-water heat exchanger, a third-stage expansion machine and a generator which are connected in sequence; a main gas adjusting module is further connected between the first gas-water heat exchanger and the gas storage equipment; the main gas adjusting module comprises a first main gas adjusting branch and a second main gas adjusting branch, wherein the first main gas adjusting branch and the second main gas adjusting branch are connected with a first ejector. An ejection fluid interface of the first ejector is at least connected with an exhaust port of the second-stage expansion machine; an air supply branch comprising an air supply adjusting module is further connected between the first-stage expansion machine and the air storage equipment; the air supply adjusting module comprises a first air supply adjusting branch and a second air supply adjusting branch which are connected with a second ejector; and an ejection fluid interface of the second ejector is at least connected with an exhaust port of the three-stage expansion machine. And residual energy of exhaust of the expansion machine can be effectively recycled.

Description

Technical Field

[0001] The present specification relates to the technical field of compressed air energy storage, and in particular to an expansion section system for compressed air energy storage. Background Art

[0002] Compressed air energy storage is an important energy storage method. Due to its advantages such as large storage energy, high power density, low operating cost and long service life, it is adopted by more and more energy storage power stations.

[0003] Compressed air energy storage usually includes two processes: compression energy storage process and expansion energy release process. Usually, during the low load period of the power grid, energy storage can be achieved by using electricity to compress gas and store it in the gas storage equipment; during the peak load period of the power grid, energy release can be achieved by using expansion energy release to release the compressed gas in the gas storage equipment to drive the air turbine to generate electricity and obtain the corresponding electricity.

[0004] In the specific process of expansion and energy release, the pressure of the compressed gas in the gas storage equipment will continue to decrease as the operating time increases. The rated operating parameters of the expansion section system are mostly designed based on certain operating parameters after technical and economic comparison, while the pressure of the actual gas storage reservoir is constantly changing, which will cause the expander to adapt to a wider load range and cannot continue to operate in the optimal operating range. For example, a throttling device may be set in front of the expander to change the inlet pressure, but this will lose some of the work capacity of the high-pressure gas. Alternatively, when the gas storage reservoir is lower than the rated pressure, the output power of the expansion section system will decrease, and even affect the stability of operation.

[0005] The existing technology is still unable to effectively solve the above problems. Utility Model Content

[0006] The purpose of the implementation mode of the present application is to provide an expansion section system for compressed air energy storage, which can effectively recycle and utilize the residual energy of the expander exhaust at different stages of the expansion energy release process, finely adjust the gas pressure in the expansion section system, and increase the expander intake flow rate, thereby enabling the expansion section system to operate continuously and stably for a long time according to the required operating parameters.

[0007] This specification provides an expansion section system for compressed air energy storage, comprising at least: an expansion pipeline and a heating pipeline;

[0008] The expansion pipeline at least includes a gas storage device, a first gas-water heat exchanger, a first-stage expander, a second gas-water heat exchanger, a second-stage expander, a third gas-water heat exchanger, a third-stage expander, and a generator connected in sequence;

[0009] The heating pipeline at least includes a high-temperature liquid storage tank, a first heating branch, and a low-temperature liquid storage tank connected in sequence; the first heating branch is connected to a first air-water heat exchanger; the heating pipeline also includes a second heating branch and a third heating branch; the second heating branch is connected to a second air-water heat exchanger, and the third heating branch is connected to a third air-water heat exchanger; the second heating branch and the third heating branch are respectively connected in parallel with the first heating branch;

[0010] A main gas regulating module is also connected between the first gas-water heat exchanger and the gas storage equipment; wherein the main gas regulating module comprises: a first main gas regulating branch and a second main gas regulating branch; the first main gas regulating branch is connected to a first ejector; the ejection fluid interface of the first ejector is at least connected to the exhaust port of the secondary expander;

[0011] In addition, an air supply branch is connected between the first-stage expander and the gas storage equipment; the air supply branch is at least connected to an air supply regulating module; wherein the air supply regulating module includes: a first air supply regulating branch and a second air supply regulating branch; the first air supply regulating branch is connected to a second ejector; the ejection fluid interface of the second ejector is at least connected to the exhaust port of the third-stage expander.

[0012] In one embodiment, a first regulating valve is further provided on the first main gas regulating branch between the first ejector and the gas storage equipment.

[0013] In one embodiment, a second regulating valve is further provided on the second main gas regulating branch.

[0014] In one embodiment, a first switch valve is further provided between the main gas regulating module and the gas storage equipment.

[0015] In one embodiment, the ejection fluid interface of the first ejector is also connected to the exhaust port of the third-stage expander and the exhaust port of the first-stage expander respectively.

[0016] In one embodiment, corresponding regulating valves are respectively provided between the ejection fluid interface of the first ejector and the exhaust port of the third-stage expander, the exhaust port of the second-stage expander, and the exhaust port of the first-stage expander.

[0017] In one embodiment, a fourth gas-water heat exchanger is further connected between the gas replenishment regulating module and the first-stage expander; wherein the fourth gas-water heat exchanger is connected to the high-temperature liquid storage tank and the low-temperature liquid storage tank through a fourth heating branch.

[0018] In one embodiment, the ejection fluid interface of the second ejector is also connected to the exhaust port of the second-stage expander and the exhaust port of the first-stage expander respectively.

[0019] In one embodiment, an air pressure sensor is further provided between the main air conditioning module and the first air-water heat exchanger.

[0020] In one embodiment, a temperature sensor is further provided between the first gas-water heat exchanger and the first-stage expander.

[0021] The expansion section system for compressed air energy storage provided in this specification at least includes: an expansion pipeline and a heating pipeline; the expansion pipeline at least includes a gas storage device, a first gas-water heat exchanger, a first-stage expander, a second gas-water heat exchanger, a second-stage expander, a third gas-water heat exchanger, a third-stage expander, and a generator connected in sequence; the heating pipeline at least includes a high-temperature liquid storage tank, a first heating branch, and a low-temperature liquid storage tank connected in sequence; the first heating branch is connected to the first gas-water heat exchanger; the heating pipeline also includes a second heating branch and a third heating branch; the second heating branch is connected to the second gas-water heat exchanger, and the third heating branch is connected to the third gas-water heat exchanger; the second heating branch and the third heating branch are respectively connected to the first heating branch and the third heating branch. The heating branches are connected in parallel; a main gas regulating module is also connected between the first gas-water heat exchanger and the gas storage equipment; wherein the main gas regulating module includes: a first main gas regulating branch and a second main gas regulating branch; the first main gas regulating branch is connected to a first ejector; the ejection fluid interface of the first ejector is at least connected to the exhaust port of the second-stage expander; and, an air supply branch is also connected between the first-stage expander and the gas storage equipment; the air supply branch is at least connected to the air supply regulating module; wherein the air supply regulating module includes: a first air supply regulating branch and a second air supply regulating branch; the first air supply regulating branch is connected to a second ejector; the ejection fluid interface of the second ejector is at least connected to the exhaust port of the third-stage expander. Based on the expansion section system of the above structure, by utilizing the first ejector in the main gas regulating module and the second ejector in the supplementary gas regulating module, it is possible to effectively recycle and utilize the residual energy of the expander exhaust at different stages of the expansion energy release, and finely adjust the operating parameters such as gas pressure in the expansion section system. At the same time, it is also possible to effectively increase the air intake flow of the expander, thereby enabling the expansion section system to operate continuously and stably for a long time in accordance with the required operating parameters, thereby obtaining a better expansion energy release effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some implementation methods recorded in this application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0023] Figure 1 A schematic diagram of the structure of an expansion section system for compressed air energy storage provided in this specification is shown;

[0024] Figure 2 A schematic diagram of the structural composition of a gas ejector in an expansion section system for compressed air energy storage provided in this specification is shown. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of this application.

[0026] See also Figure 1 As shown, this specification provides an expansion section system for compressed air energy storage, which may at least include: an expansion pipeline and a heating pipeline;

[0027] The expansion pipeline at least includes a gas storage device, a first gas-water heat exchanger (which can be simply referred to as gas-water heat exchanger 1), a first-stage expander, a second gas-water heat exchanger (which can be simply referred to as gas-water heat exchanger 2), a second-stage expander, a third gas-water heat exchanger (which can be simply referred to as gas-water heat exchanger 3), a third-stage expander, and a generator (which can be simply referred to as G) connected in sequence;

[0028] The heating pipeline at least includes a high-temperature liquid storage tank, a first heating branch, and a low-temperature liquid storage tank connected in sequence; the first heating branch is connected to a first air-water heat exchanger; the heating pipeline also includes a second heating branch and a third heating branch; the second heating branch is connected to a second air-water heat exchanger, and the third heating branch is connected to a third air-water heat exchanger; the second heating branch and the third heating branch are respectively connected in parallel with the first heating branch;

[0029] A main gas regulating module is also connected between the first gas-water heat exchanger and the gas storage equipment; wherein the main gas regulating module comprises: a first main gas regulating branch and a second main gas regulating branch; the first main gas regulating branch is connected to a first ejector; the ejection fluid interface of the first ejector is at least connected to the exhaust port of the secondary expander;

[0030] In addition, an air supply branch (or air supply pipeline, air supply pipe, etc.) is connected between the first-stage expander and the gas storage equipment; the air supply branch is at least connected to an air supply regulating module; wherein the air supply regulating module includes: a first air supply regulating branch and a second air supply regulating branch; the first air supply regulating branch is connected to a second ejector; the ejection fluid interface of the second ejector is at least connected to the exhaust port of the third-stage expander.

[0031] The gas storage equipment stores high-pressure gas, which can be compressed by the compression section system through compression energy storage, and then stored in the gas storage equipment.

[0032] The high pressure gas may be air, carbon dioxide, or other suitable gas. The type of the high pressure gas is not limited in this specification.

[0033] The above-mentioned gas storage equipment may specifically include any one of the following: underground salt caverns, artificial chambers, steel containers, etc.

[0034] For details, see Figure 1 As shown, the expansion pipeline is sequentially connected with at least gas storage equipment, a first gas-water heat exchanger, a first-stage expander, a second gas-water heat exchanger, a second-stage expander, a third gas-water heat exchanger, a third-stage expander, a generator and other equipment.

[0035] Based on the expansion pipeline, when the expansion section system is used for expansion and energy release, the high-pressure gas in the gas storage equipment will flow into the first gas-water heat exchanger through the corresponding pipeline for the first heating treatment; the heated gas will enter the first-stage expander through the air inlet of the first-stage expander to perform work, complete the first-stage expansion energy release, and then be discharged through the exhaust port of the first-stage expander.

[0036] The exhausted gas will flow into the second gas-water heat exchanger through the corresponding pipeline for a second heating treatment; the heated gas will enter the secondary expander through the air inlet of the secondary expander to perform work, complete the second stage expansion and release energy, and then be discharged through the exhaust port of the secondary expander.

[0037] The exhausted gas will flow into the third gas-water heat exchanger through the corresponding pipeline for the third heating treatment; the heated gas will enter the third-stage expander through the air inlet of the third-stage expander to perform work, complete the third-stage expansion and release energy, and then be discharged through the exhaust port of the third-stage expander.

[0038] During the above expansion and energy release process, the generator can collect and utilize the energy released by the gas in the expander to obtain the required electrical energy.

[0039] For details, see Figure 1 As shown, the first gas-water heat exchanger can be connected to the first heating branch; the second gas-water heat exchanger can be connected to the second heating branch; and the third gas-water heat exchanger can be connected to the third heating branch.

[0040] The first heating branch, the second heating branch and the third heating branch are connected in parallel and are respectively connected to the high temperature liquid storage tank and the low temperature liquid storage tank to form a heating pipeline. The high temperature liquid storage tank stores a high temperature heat storage medium. The low temperature liquid storage tank stores a low temperature heat storage medium.

[0041] The heat storage medium may specifically include one or more of the following combinations: water, heat transfer oil, molten salt, etc. In specific implementation, a suitable type of heat storage medium may also be selected according to the temperature requirements in the actual working scenario.

[0042] Based on the heating pipeline, when the expansion section system is used for expansion and energy release, the high-temperature heat storage medium in the high-temperature liquid storage tank flows into the first gas-water heat exchanger through the corresponding pipeline, and heats the gas flowing through the first gas-water heat exchanger; after heating, the low-temperature heat storage medium with a reduced temperature flows into the low-temperature liquid storage tank through the corresponding pipeline. In a similar manner, the gas flowing through the second gas-water heat exchanger and the gas flowing through the third gas-water heat exchanger can be heated by the second gas-water heat exchanger and the third gas-water heat exchanger, respectively.

[0043] See also Figure 1 As shown, a main gas regulating module is also connected between the first gas-water heat exchanger and the gas storage equipment. The main gas regulating module is included, and the pipeline between the gas storage equipment and the first-stage expander can be recorded as the main gas pipeline. The main gas regulating module is used to regulate the gas input to the air inlet of the first-stage expander through the main gas pipeline.

[0044] Specifically, the main gas regulating module may include a first main gas regulating branch and a second main gas regulating branch, wherein the first main gas regulating branch is at least connected to a first ejector.

[0045] Correspondingly, in specific implementation, the gas in the main gas pipeline can be regulated through the first main gas regulating branch and / or the second main gas regulating branch in the main gas regulating module.

[0046] A gas supply branch may be connected between the primary expander and the gas storage equipment. The gas supply branch is connected in parallel with the main gas pipeline. The gas supply branch is also connected to a gas supply regulating module. The gas supply regulating module is specifically used to regulate the gas input to the primary expander through the gas supply branch.

[0047] Specifically, the above-mentioned air supply regulating module may include a first air supply regulating branch and a second air supply regulating branch. The first air supply regulating branch is at least connected to the second ejector.

[0048] Correspondingly, in a specific implementation, the gas in the gas supplement branch can be regulated through the first gas supplement regulating branch and / or the second gas supplement regulating branch in the gas supplement regulating module.

[0049] The first ejector and the second ejector may be a gas ejector. Figure 2 The gas ejector at least comprises: a suction section, a mixing section, and a diffuser section.

[0050] The suction section at least comprises a working nozzle, and the suction section is also provided with a working fluid interface and an ejection fluid interface. The diffuser section is also provided with a mixed fluid outlet.

[0051] In specific implementation, for the first ejector, the working fluid interface can be connected to the gas storage equipment through a pipeline, the mixed fluid outlet can be connected to the air inlet of the first-stage expansion machine through a pipeline after passing through the first gas-water heat exchanger, and the ejection fluid interface can be connected to the exhaust port of at least the third-stage expansion machine.

[0052] Based on the above-mentioned first ejector, while high-pressure gas from the gas storage equipment is connected as the working fluid through the working fluid interface, the gas with relatively low pressure after expansion and work output from the exhaust port of the three-stage expander can be connected through the ejection fluid interface as the ejection fluid. Then, the entrainment effect of the high-pressure gas (i.e., the working fluid) in the gas ejector on the low-pressure gas (i.e., the ejection fluid) can be utilized to achieve throttling and pressure reduction of the high-pressure gas inside the ejector, and at the same time, it can also effectively entrain part of the low-pressure gas, and realize that part of the throttling loss of the main gas flow is converted into the work capacity of the entrained gas flow, and the flow rate of the mixed fluid finally output by the gas ejector and acting on the first-stage expander is increased, which helps to improve the gas flow rate and work capacity of the gas connected to the gas inlet of the first-stage expander, thereby improving the expansion energy release effect of the first-stage expander.

[0053] In this way, by utilizing the above-mentioned first ejector, the residual energy of the expander exhaust can be effectively recovered and utilized while utilizing the main gas regulating module for gas replenishment or throttling, so as to finely adjust the gas pressure of the main gas flow output by the main gas regulating module and acting on the first-stage expander. On the one hand, it alleviates the rate of pressure drop in the gas storage reservoir, and on the other hand, it can stably maintain the gas pressure parameters of the main gas flow participating in the expansion energy release at the required operating parameters, which helps to keep the expansion section system able to operate continuously and stably. At the same time, since the gas discharged from the expander is introduced and reused, the gas flow rate of the main gas flow participating in the expansion work input to the first-stage expander is increased, thereby obtaining a better expansion energy release effect.

[0054] Similarly, for the second ejector, the working fluid interface can be connected to the gas storage equipment through a pipeline, the mixed fluid outlet can be connected to the first-stage expander through a pipeline, and the ejection fluid interface can be connected to the exhaust port of at least the third-stage expander.

[0055] In this way, the above-mentioned second ejector can be used to input the supplementary air flow and assist the main gas regulating module in the supplementary air processing, while effectively recovering and utilizing the residual energy of the expander exhaust, so as to finely adjust the gas pressure output by the supplementary air regulating module and acting on the first-stage expander to achieve the corresponding operating parameters; at the same time, the gas flow rate of the supplementary air flow input to the first-stage expander to participate in the expansion energy release is further increased, so that a relatively better expansion energy release effect can be obtained.

[0056] The expansion section system based on the above structure, by utilizing the first ejector in the main gas regulating module and the second ejector in the supplementary gas regulating module, can effectively recycle the residual energy of the expander exhaust in different stages of expansion energy release, such as the throttling stage and the supplementary gas stage, and finely adjust the gas pressure in the expansion section system; at the same time, it can also increase the expander air intake flow rate, thereby enabling the expansion section system to operate stably and continuously according to the required operating parameters, thereby obtaining a better expansion energy release effect.

[0057] In some embodiments, see Figure 1 As shown, a first regulating valve is also arranged on the first main gas regulating branch between the first ejector and the gas storage equipment.

[0058] In a specific implementation, the flow rate of the working fluid input to the first ejector can be adjusted by the first regulating valve, so that the first main gas regulating branch can be controlled and adjusted relatively precisely.

[0059] In some embodiments, see Figure 1 As shown, a second regulating valve is also provided on the second main gas regulating branch.

[0060] During specific implementation, the flow rate of the second main gas regulating branch can be adjusted by the second regulating valve, so that more precise control and adjustment of the second main gas regulating branch can be achieved.

[0061] In some embodiments, see Figure 1 As shown, a first switch valve is also arranged between the main gas regulating module and the gas storage equipment.

[0062] During specific implementation, the main gas pipeline can be opened and closed by the first switch valve.

[0063] In some embodiments, see Figure 1 As shown, a fourth gas-water heat exchanger (which can be simply referred to as gas-water heat exchanger 4) can be specifically connected between the gas replenishment regulation module and the first-stage expander; wherein the fourth gas-water heat exchanger is connected to the high-temperature liquid storage tank and the low-temperature liquid storage tank through a fourth heating branch.

[0064] In specific implementation, the gas output by the gas replenishment regulation module can be first heated by the fourth gas-water heat exchanger and then input into the first-stage expander to assist the gas output through the main gas pipeline and participate in the expansion energy release based on the first-stage expander.

[0065] In some embodiments, see Figure 1 As shown, a third regulating valve may also be provided on the first air supply regulating branch between the second ejector and the air storage equipment.

[0066] Accordingly, the third regulating valve can be used to perform more precise control and regulation on the first air supply regulating branch.

[0067] A fourth regulating valve may also be provided on the second gas supplement regulating branch circuit. Accordingly, the fourth regulating valve may be used to perform relatively fine control and regulation on the second gas supplement regulating branch circuit.

[0068] In addition, a second switch valve is also provided on the gas supply branch between the gas supply regulating module and the gas storage equipment.

[0069] Correspondingly, the second fast-tube valve can be used to control the on-off of the gas supplement branch.

[0070] In some embodiments, see Figure 1 As shown, the ejection fluid interface of the first ejector can also be connected to the exhaust port of the third-stage expander and the exhaust port of the first-stage expander respectively.

[0071] Based on the above structure, according to specific working conditions and processing requirements, gases of different pressures discharged from different expanders can be flexibly recovered and utilized as injection fluids, introduced into the first injector, and the main airflow can be adjusted to meet diverse adjustment requirements.

[0072] Furthermore, gases of different pressures discharged from different expanders may be used in combination, mixed first, and then used as ejection fluids to be introduced into the first ejector to adjust the main airflow to meet relatively more complex adjustment requirements.

[0073] In some embodiments, corresponding regulating valves are respectively provided between the ejection fluid interface of the first ejector and the exhaust port of the third-stage expander, the exhaust port of the second-stage expander, and the exhaust port of the first-stage expander.

[0074] For details, please refer to Figure 1 As shown, a fifth regulating valve is also arranged between the ejection fluid interface of the first ejector and the exhaust port of the first-stage expansion machine.

[0075] Similarly, a sixth regulating valve is provided between the ejection fluid interface of the first ejector and the exhaust port of the second-stage expander. A seventh regulating valve is provided between the ejection fluid interface of the first ejector and the exhaust port of the third-stage expander.

[0076] Accordingly, the regulating valve can be used to more finely adjust the flow rate of the exhaust gas from different expanders fed into the first ejector, so as to achieve more precise regulation.

[0077] In some embodiments, the ejection fluid interface of the second ejector can also be connected to the exhaust port of the secondary expander and the exhaust port of the primary expander respectively. Accordingly, according to specific working conditions and processing requirements, the gases of different pressures discharged from different expanders can be flexibly recovered and used as ejection fluids, introduced into the second ejector, and the supplementary gas flow can be adjusted to meet diverse adjustment requirements.

[0078] Specifically, corresponding regulating valves are respectively provided between the ejection fluid interface of the second ejector and the exhaust port of the third-stage expander, the exhaust port of the second-stage expander, and the exhaust port of the first-stage expander.

[0079] For example, see Figure 1 As shown, an eighth regulating valve is also arranged between the ejection fluid interface of the second ejector and the exhaust port of the first-stage expansion machine.

[0080] Similarly, a ninth regulating valve is provided between the ejection fluid interface of the second ejector and the exhaust port of the second-stage expander. A tenth regulating valve is provided between the ejection fluid interface of the second ejector and the exhaust port of the third-stage expander.

[0081] In this way, the gas flow rate of the exhaust gas from different expanders fed into the second ejector can be more accurately regulated and controlled.

[0082] In some embodiments, considering that the air pressure of the supplementary air flow output by the supplementary air regulation module is often relatively lower than the air pressure of the main air flow output by the main air regulation module; and the main air regulation module is connected to the air inlet of the first-stage impeller of the first-stage expansion machine after the first air-water heat exchanger; the main air flow output by the main air regulation module will pass through the air inlet of the first-stage impeller into the first-stage expansion machine to perform work.

[0083] In this case, if the air supply regulating module is directly connected to the air inlet of the first-stage impeller of the first-stage expander through the fourth air-water heat exchanger, the air supply flow with a lower air pressure output by the air supply regulating module will be directly mixed with the main air flow. Direct mixing of airflows of different pressures will produce airflow fluctuations, which may easily lead to safety accidents; on the other hand, direct mixing will cause partial potential energy loss of the high-pressure airflow, reducing the overall work capacity.

[0084] Considering that after the main airflow enters the first-stage expander and starts to do work, the potential energy of the main airflow will be continuously converted into corresponding electrical energy through expansion work, resulting in a decrease in the potential energy of the main airflow and a decrease in the air pressure of the main airflow.

[0085] Therefore, the air supply regulating module can be connected to the air inlet of the middle-stage impeller of the first-stage expander through the fourth air-water heat exchanger.

[0086] Based on the above structure, the main airflow encountered by the supplementary airflow output by the supplementary air flow adjustment module after entering the first-stage expander through the air inlet of the intermediate-stage impeller is an airflow with a pressure that is the same or similar to the air pressure of the supplementary airflow after a period of work. In this way, on the one hand, the gas potential energy can be effectively utilized to generate more electrical energy, reduce the waste of potential energy, and obtain a better expansion energy release effect; on the other hand, it can also avoid safety hazards and ensure that the expansion section system can operate safely and stably.

[0087] In some embodiments, see Figure 1 As shown, a third switch valve may be connected between the first gas-water heat exchanger and the high-temperature liquid storage tank; and a fourth switch valve may be connected between the first gas-water heat exchanger and the low-temperature liquid storage tank.

[0088] Similarly, a fifth switch valve may be connected between the second gas-water heat exchanger and the high-temperature liquid storage tank; and a sixth switch valve may be connected between the second gas-water heat exchanger and the low-temperature liquid storage tank.

[0089] A seventh switch valve may be connected between the third gas-water heat exchanger and the high-temperature liquid storage tank; and an eighth switch valve may be connected between the third gas-water heat exchanger and the low-temperature liquid storage tank.

[0090] A ninth switch valve may be connected between the fourth gas-water heat exchanger and the high-temperature liquid storage tank; and a tenth switch valve may be connected between the fourth gas-water heat exchanger and the low-temperature liquid storage tank.

[0091] Based on the above-mentioned switch valve, the corresponding heating branch can be controlled more effectively, so as to heat the input airflow of the relevant expander more accurately.

[0092] In some embodiments, an air pressure sensor is further provided between the main air conditioning module and the first air-water heat exchanger.

[0093] In specific implementation, the air pressure sensor can be used to detect the actual air pressure of the main airflow input to the first-stage expander, and then the output main airflow can be more specifically adjusted through the main air regulation module according to the actual air pressure of the main airflow to meet the corresponding operating parameters.

[0094] Specifically, a corresponding air pressure sensor may be provided between the air supply regulating module and the fourth air-water heat exchanger. Accordingly, the air supply regulating module may be adjusted in a targeted manner according to the actual air pressure of the supply air flow detected by the air pressure sensor.

[0095] In some embodiments, a temperature sensor is further provided between the first gas-water heat exchanger and the first-stage expander.

[0096] In a specific implementation, the corresponding first heating branch can be adjusted in a targeted manner according to the temperature of the airflow input to the first-stage expander detected by the temperature sensor, so that the airflow temperature meets the corresponding operating parameters.

[0097] Similarly, corresponding temperature sensors may be provided between the second gas-water heat exchanger and the second-stage expander, and between the third gas-water heat exchanger and the third-stage expander, respectively.

[0098] In some embodiments, the expansion section system may further include a processor, wherein the processor may be connected to the temperature sensor, the air pressure sensor, and the corresponding switch valve and regulating valve respectively.

[0099] Accordingly, during specific implementation, the processor can adjust one or more of the relevant heating branches, air supply adjustment modules, and main air adjustment modules by adjusting the corresponding regulating valves and switch valves according to the temperature parameters and air pressure parameters collected by the temperature sensor and the air pressure sensor, so as to realize automatic adjustment of the expansion section system, effectively recycle and utilize the residual energy of the expander exhaust at different stages of expansion energy release, finely adjust the gas pressure in the expansion section system, and increase the air intake flow of the expander, so that the expansion section system can operate stably and continuously according to the required operating parameters to obtain better expansion energy release effect.

[0100] In some embodiments, in the process of expanding and releasing energy using the expansion section system of the above structure, in the throttling stage, according to the gas pressure in the gas storage equipment, the first switch valve can be opened first and the second switch valve can be closed; at the same time, the first regulating valve is adjusted to 0, and the second main gas regulating branch is used alone to perform throttling processing by adjusting the second regulating valve, and the air pressure of the main gas flow is adjusted at the same time, so that the air pressure and the air flow meet the corresponding operating parameters. After a period of operation, when the gas pressure in the gas storage equipment drops, the second regulating valve can be adjusted to 0, and the first regulating valve, and at least one of the fifth regulating valve, the sixth regulating valve, and the seventh regulating valve are adjusted, and the throttling processing is performed based on the first ejector using the first main gas regulating branch, and the air pressure of the main gas flow is adjusted at the same time, so that the air pressure and the air flow meet the corresponding operating parameters.

[0101] After a period of operation, when the gas consumption of the gas storage equipment is large and the gas pressure of the gas storage equipment is less than the preset reference threshold, the gas replenishment stage is entered. For a period of time at the beginning of the gas replenishment stage, the second switch valve can be opened to adjust the third regulating valve to 0; by adjusting the first regulating valve, and at least one of the fifth regulating valve, the sixth regulating valve, and the seventh regulating valve, while adjusting the main gas flow based on the first ejector using the first main gas regulating branch, the fourth regulating valve can also be adjusted to use the second gas replenishment branch to adjust the supplementary gas flow, and the adjusted supplementary gas flow is input to the first-stage expander for gas replenishment, so as to cooperate with the main gas flow to complete the expansion energy release according to the corresponding operating parameters. After running for a period of time and the gas pressure of the gas storage equipment is further reduced, the fourth regulating valve can be adjusted to 0, and the supplementary air flow can be adjusted by adjusting the third regulating valve using the first supplementary air branch to cooperate with the adjustment of the main air flow to supplement air, so that the expansion section system can operate based on the corresponding operating parameters to complete the expansion energy release, and avoid the situation in which, during the expansion energy release process, the gas volume of the gas storage equipment continues to decrease and the gas pressure continues to decrease as the operating time of the expansion section system increases, resulting in the expander being unable to continuously and stably perform work and release energy according to the rated operating parameters, so that the overall operating efficiency and output power of the expansion section system are relatively stable.

[0102] In summary, based on the expansion section system of the above structure, by utilizing the first ejector in the main gas regulating module and the second ejector in the supplementary gas regulating module, it is possible to effectively recycle and utilize the residual energy of the expander exhaust at different stages of the expansion energy release, and finely adjust the gas pressure in the expansion section system. At the same time, it is also possible to increase the air intake flow of the expander, thereby enabling the expansion section system to operate stably and continuously in accordance with the required operating parameters, thereby obtaining better expansion energy release effects.

[0103] In a specific scenario example, the expansion section system for compressed air energy storage provided in this specification can be used to construct a compressed gas energy storage operation and regulation system suitable for actual engineering.

[0104] In this scenario example, considering that during the energy discharge process of the compressed gas energy storage power station, the pressure of the compressed gas in the gas storage equipment will continue to decrease with the operating time, and the rated operating conditions (operating parameters) of the expansion system are usually designed based on a certain gas storage equipment, which will cause a certain deviation between the actual operating conditions and the theoretical design conditions, affecting the operating efficiency and output power of the expansion system.

[0105] Furthermore, considering the current compressed gas energy storage power station, in order to keep the expander in a relatively economical and efficient operating state throughout the expansion and power generation stage, the expansion system (or expansion section system) usually adopts two adjustment modes: throttling adjustment and air supply valve adjustment. If only throttling adjustment is used, the flow area will be too large, and the throttling loss will be large in the early stage of discharge; if only air supply valve adjustment is used, the flow area will be too small, and the air supply loss will be large in the later stage of discharge.

[0106] In view of the root cause of the above problems, it is considered to construct a compressed gas energy storage power station operation and regulation system based on the principle of gas ejectors. The system can use the entrainment effect of the gas ejector on the low-pressure gas, and can effectively entrain part of the low-pressure gas while throttling and reducing the pressure inside the high-pressure gas ejector, so as to realize the conversion of part of the throttling loss of the main gas flow into the work capacity of the entrained gas flow, and increase the gas mass flow rate at the ejector outlet, which helps to improve the gas flow rate and work capacity at the expander inlet. This regulation method takes into account the advantages of both gas replenishment operation and throttling operation, and effectively recovers the work capacity of exhaust gas at each stage of the expander. The various combinations of gas ejectors and regulating valves make the system highly adaptable in all operating ranges.

[0107] Specifically, in terms of overall layout, the above-mentioned compressed gas energy storage operation and regulation system mainly includes equipment such as an expander, an air-water heat exchanger, a high-temperature heat storage tank (for example, a high-temperature liquid storage tank), a low-temperature heat storage tank (for example, a low-temperature liquid storage tank), a gas ejector and a gas storage equipment, and also includes a number of switch valves and regulating valves. Taking the compressed gas energy storage system with a three-stage expander and a one-time gas replenishment operation as an example, the first-stage expander, the second-stage expander, and the third-stage expander are arranged in series with the air-water heat exchanger 1 (for example, the first air-water heat exchanger), the air-water heat exchanger 2 (for example, the second air-water heat exchanger), and the air-water heat exchanger 3 (for example, the third air-water heat exchanger). The air side pipeline inlet and outlet of each stage of the air-water heat exchanger are respectively connected to the upper and lower expanders, and the heat storage medium side pipeline inlet and outlet are respectively connected to the high-temperature heat storage tank and the low-temperature heat storage tank. The gas storage equipment can be one or more combinations of underground salt caves, artificial chambers, steel containers, etc. The compressed gas can be air or carbon dioxide gas.

[0108] In the connection of the first-stage expander, the first-stage expander can be provided with two gas inlets, which are respectively connected to the gas storage equipment through the main gas pipeline (for example, the main gas pipeline) and the supplementary gas pipeline (for example, the supplementary gas pipeline), wherein the main gas pipeline is the first gas supply pipeline of the expander, and the high-pressure gas enters the first-stage expander for expansion and power generation after passing through the main gas pipeline, the main gas regulating module and the gas-water heat exchanger 1, and the supplementary gas pipeline is the first gas supply pipeline of the expander, and the high-pressure gas enters the first-stage expander for expansion and power generation after passing through the supplementary gas pipeline, the supplementary gas regulating module and the gas-water heat exchanger 4 (for example, the fourth heat exchanger). Among them, the gas in the main gas pipeline enters the expander from the first-stage impeller of the first-stage expander, and the gas in the supplementary gas pipeline enters the expander from the middle stage of the first-stage expander.

[0109] On the main gas regulating module and the supplementary gas regulating module, the main gas regulating module includes the first regulating valve, the second regulating valve and the first ejector, and the supplementary gas regulating module includes the third regulating valve, the fourth regulating valve and the second ejector, and the two groups of regulating modules have the same configuration. The functions are similar, and the operation mode and working flow of the main gas flow and the supplementary gas flow are adjusted in the expansion section respectively. The first and second ejectors are both gas ejectors, which include working fluid, ejection fluid and mixed fluid, and are intended to form a suction effect on the low-pressure ejection fluid through the acceleration and throttling and pressure reduction effect of the working fluid in the nozzle, and after being fully mixed in the mixing section, the pressure is further increased by the diffuser section and then ejected. The working fluid comes from the high-pressure fluid in the gas storage reservoir, and the ejection fluid comes from the exhaust of the first-stage expander, the second-stage expander, and the third-stage expander. The mixed fluid can lead to the main gas inlet or the supplementary gas inlet of the first-stage expander. The second regulating valve and the fourth regulating valve and their pipelines are bypass pipelines, which are used for operation control that does not participate in the operation regulation of gas ejection but is only regulated by the opening of the regulating valve. The first regulating valve is connected to the first ejector, the third regulating valve is connected to the second ejector, and the first regulating valve and the third regulating valve respectively control the flow rate of the working fluid entering the ejector.

[0110] Regarding the source of the ejector fluid for the gas ejector, considering that the gas parameters at the outlets of the expanders at each stage are quite different (for example, when the exhaust pressure of the third-stage expander is 0.1MPa, the exhaust at the outlet of the second-stage expander can be 0.4-0.6MPa), in order to maximize the conversion of the working capacity of the high-pressure gas into electrical energy, it is usually not recommended to mix the exhaust of the two stages as the ejector fluid, which will sacrifice the working capacity of the high-pressure parameter gas. Therefore, the embodiments of this scheme all use a single gas source of the exhaust of a certain stage as the ejector fluid. However, if after technical and economic comparison, the exhaust of multiple expanders is mixed as the ejector fluid, it can still have the advantage of improving the performance of the expander, and the exhaust of multiple expanders can also be mixed as the ejector fluid.

[0111] Regarding the expander system, the first-stage expander, the second-stage expander, and the third-stage expander are respectively connected in series with the air-water heat exchanger 1, the air-water heat exchanger 2, and the air-water heat exchanger 3. The first-stage expansion is provided with a main gas inlet and a supplementary gas inlet, which respectively receive the main gas flow and the supplementary gas flow from the gas storage reservoir. The air-water heat exchanger 1 and the air-water heat exchanger 4 are respectively used to heat the main gas flow and the supplementary gas flow, and heat them to the rated temperature of the expander inlet to enhance the working capacity of the gas flow. The air-water heat exchanger 2 and the air-water heat exchanger 3 are respectively used to heat the exhaust gas flow of the first-stage expander and the second-stage expander, and heat them again to the rated temperature to enhance the working capacity of the gas flow. The outlet of the first-stage expander is provided with a fifth regulating valve and a sixth regulating valve, the outlet of the second-stage expander is provided with a seventh regulating valve and an eighth regulating valve, and the outlet of the third-stage expander is provided with a ninth regulating valve and a tenth regulating valve. The sixth regulating valve, the eighth regulating valve and the tenth regulating valve respectively control the amount of air entering the inlet of the first ejector fluid, and the fifth regulating valve, the seventh regulating valve and the ninth regulating valve respectively control the amount of air entering the inlet of the second ejector fluid.

[0112] Regarding the heat storage and heat exchange system, the inlets of the four gas-water heat exchangers are all connected to the high-temperature liquid storage tank, and the outlets are all connected to the low-temperature liquid storage tank, and switch valves are respectively set at the inlet and outlet to control the on-off of the heat storage medium. The heat storage medium realizes the recovery and storage of heat in the compression process and the release of heat in the expansion stage. The heat storage medium can be one of water, heat transfer oil or molten salt, etc., or a combination of them according to the heat storage temperature.

[0113] In addition, in this scenario, a compressed gas energy storage system with a three-stage expander and a single air supply is used as an example. Only one air supply port is set in the first-stage expander. If there are multiple air supply ports or air supply is provided at the inlet of other stages of expanders or at a certain intermediate stage, the system can still be applied to achieve operational regulation of the expansion process, which should be regarded as an extended use of this scheme and should also be regarded as within the protection scope of this scheme.

[0114] Through the above scenario examples, it is verified that the expansion section system for compressed air energy storage provided in this specification can solve the problem that the throttling loss caused by the throttling adjustment and air supply valve adjustment methods currently used by the expander is large and cannot be effectively recovered, and the throttling method is not flexible and adjustable, resulting in poor performance of the unit during the entire operation period. By designing a compressed gas energy storage power station operation adjustment device based on the principle of a gas ejector, efficient and flexible operation adjustment of the expansion and power generation operation process of the compressed gas energy storage power station can be achieved. Specifically, the entrainment effect of the high-pressure gas in the gas ejector on the low-pressure gas can be utilized to achieve the high-pressure gas throttling and depressurization inside the ejector while effectively entraining part of the low-pressure gas, so that part of the throttling loss of the main gas flow is converted into the work capacity of the entrained gas flow, and the gas mass flow rate at the ejector outlet is increased, which helps to improve the gas flow rate and work capacity at the inlet of the expander. This regulation method takes into account the advantages of both gas-supply operation and throttling operation, and effectively recovers the working capacity of exhaust gas at each stage of the expander. The various combinations of gas ejectors and regulating valves make the system highly adaptable in all operating ranges.

[0115] Each embodiment in this specification is described in a progressive manner, and the same and similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the relevant embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the relevant embodiment. In the description of this specification, the description of the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of this specification. In this specification, the schematic representation of the above terms does not necessarily target the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, in the absence of contradiction, a person skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0116] The above is only an example of the embodiment of the present specification and is not intended to limit the embodiment of the present specification. For those skilled in the art, the embodiment of the present specification may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the embodiment of the present specification shall be included in the scope of the claims of the embodiment of the present specification.

Claims

1. An expansion section system for compressed air energy storage, characterized in that: At least: Expansion lines and heating lines; The expansion pipeline at least includes a gas storage device, a first gas-water heat exchanger, a first-stage expander, a second gas-water heat exchanger, a second-stage expander, a third gas-water heat exchanger, a third-stage expander, and a generator connected in sequence; The heating pipeline at least includes a high-temperature liquid storage tank, a first heating branch, and a low-temperature liquid storage tank connected in sequence; the first heating branch is connected to a first air-water heat exchanger; the heating pipeline also includes a second heating branch and a third heating branch; the second heating branch is connected to a second air-water heat exchanger, and the third heating branch is connected to a third air-water heat exchanger; the second heating branch and the third heating branch are respectively connected in parallel with the first heating branch; A main gas regulating module is also connected between the first gas-water heat exchanger and the gas storage equipment; wherein the main gas regulating module comprises: a first main gas regulating branch and a second main gas regulating branch; the first main gas regulating branch is connected to a first ejector; the ejection fluid interface of the first ejector is at least connected to the exhaust port of the secondary expander; In addition, an air supply branch is connected between the first-stage expander and the gas storage equipment; the air supply branch is at least connected to an air supply regulating module; wherein the air supply regulating module includes: a first air supply regulating branch and a second air supply regulating branch; the first air supply regulating branch is connected to a second ejector; the ejection fluid interface of the second ejector is at least connected to the exhaust port of the third-stage expander.

2. The expansion section system for compressed air energy storage according to claim 1, characterized in that: A first regulating valve is also provided on the first main gas regulating branch between the first ejector and the gas storage equipment.

3. The expansion section system for compressed air energy storage according to claim 2, characterized in that: A second regulating valve is also provided on the second main gas regulating branch.

4. The expansion section system for compressed air energy storage according to claim 3, characterized in that: A first switch valve is also arranged between the main gas regulating module and the gas storage equipment.

5. The expansion section system for compressed air energy storage according to claim 3, characterized in that: The ejection fluid interface of the first ejector is also connected to the exhaust port of the first-stage expander and the exhaust port of the third-stage expander respectively.

6. The expansion section system for compressed air energy storage according to claim 5, characterized in that: Corresponding regulating valves are also provided between the ejection fluid interface of the first ejector and the exhaust port of the third-stage expander, the exhaust port of the second-stage expander, and the exhaust port of the first-stage expander.

7. The expansion section system for compressed air energy storage according to claim 1, characterized in that: A fourth gas-water heat exchanger is also connected between the gas replenishment regulating module and the first-stage expander; wherein the fourth gas-water heat exchanger is connected to the high-temperature liquid storage tank and the low-temperature liquid storage tank through a fourth heating branch.

8. The expansion section system for compressed air energy storage according to claim 1, characterized in that: The ejection fluid interface of the second ejector is also connected to the exhaust port of the second-stage expander and the exhaust port of the first-stage expander respectively.

9. The expansion section system for compressed air energy storage according to claim 1, characterized in that: An air pressure sensor is also arranged between the main air regulating module and the first air-water heat exchanger.

10. The expansion section system for compressed air energy storage according to claim 1, characterized in that: A temperature sensor is also arranged between the first gas-water heat exchanger and the first-stage expander.

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