Large-capacity compressed gas energy storage power station expansion machine starting pipe warming and pressure relief system

Abstract

The utility model discloses a starting pipe warming and pressure relief system for an expansion machine of a high-capacity compressed gas energy storage power station, and relates to the technical field of expansion machines of compressed gas energy storage power stations. The system comprises a gas storage, an n-stage expansion machine and an n-stage heat exchanger, an outlet of the heat exchanger is connected with a first inlet of the expansion machine and a second inlet of the expansion machine, and the first outlet and the second outlet of the expansion machine are connected with an inlet of the next-stage heat exchanger; and the starting warm pipe / turning control valve group is connected with the main shut-off valve in parallel and comprises a bypass regulating valve and a bypass regulating valve inlet and outlet shut-off valve. The first heating pipe / pressure relief regulating valve and the second heating pipe / pressure relief regulating valve which are respectively arranged are used for regulating the heating pipe air quantity of the two air inlet pipelines of each stage of expansion machine, so that the heating rates of the heating pipes on the two sides are balanced, and the heating rates of the two air inlet pipelines with different lengths are the same; the pipe heating time and the pipe heating gas consumption are reduced, and the starting speed and the electricity-electricity conversion efficiency of a power station are improved.

Description

Technical Field

[0001] This utility model relates to the field of expander technology in compressed gas energy storage power stations, and more specifically, it is a start-up, warm-up, and pressure relief system for expanders in large-capacity compressed gas energy storage power stations. Background Technology

[0002] Compressed gas energy storage systems are currently recognized as a large-capacity, ultra-long-duration energy storage technology comparable to pumped storage. They can provide auxiliary services to the power grid such as peak shaving, frequency regulation, phase regulation, black start, and rotational inertia, and are considered an effective supplement to pumped storage power stations. They have received widespread attention from scholars at home and abroad.

[0003] Domestic research on compressed gas energy storage started relatively late, but engineering practice is at the forefront, covering everything from kilowatt-level pilot units to 300MW-level demonstration units. Large-capacity compressed gas energy storage power stations already connected to the grid include the 60MW Jintan project in Jiangsu, the 100MW Zhangjiakou North project in Hebei, the 300MW Yingcheng project in Hubei, and the 300MW Feicheng project in Shandong. Compared with pumped storage power stations, these demonstration projects still lag behind in terms of power-to-power conversion efficiency, grid response speed, and electricity pricing policies, and there is still a long way to go before large-scale application. Therefore, further improving power station conversion efficiency, accelerating unit start-up and shutdown response speed, and formulating reasonable electricity pricing policies are essential for supporting the large-scale development of compressed gas energy storage power stations.

[0004] To improve the power conversion efficiency of a power plant, in addition to focusing on improving the efficiency of the main and auxiliary equipment and optimizing the system design during normal operation, the impact of the unit start-up and shutdown phases on the power plant's conversion efficiency should not be ignored. This includes speeding up the start-up time of the compressor unit, reducing power consumption during the start-up phase, reducing the start-up time of the expander unit, and reducing gas consumption during the start-up phase. For the expander unit, reducing gas consumption during the start-up phase can be achieved by optimizing the expander start-up system.

[0005] Compressed gas energy storage power station expanders all employ multi-stage expansion, with each expander inlet equipped with a heat exchanger to heat the inlet gas. During the unit startup phase, especially under hot or warm-state startup conditions, it is essential to ensure that the gas temperature entering the expander is higher than the expander cylinder temperature. This prevents the cylinder from being affected by the low-temperature airflow, which could impact the dynamic and static clearances of the expander and thus affect the stable operation of the unit. Therefore, expanders are typically equipped with a warm-up system. Figure 2As shown, a conventional expander warm-up system typically employs a staged warm-up scheme. Gas from the storage tank is heated by a primary heat exchanger, preheating the pipeline from the heat exchanger outlet to the primary expander inlet. This preheated gas is then discharged to the atmosphere via a warm-up branch pipe before the primary expander inlet shut-off valve. After preheating of the pipeline before the primary expander inlet, the primary expander inlet shut-off valve and regulating valve are opened, allowing the gas to enter the secondary heat exchanger. After being heated by the heat exchanger, the gas preheats the secondary expander inlet pipeline before being discharged to the atmosphere via the warm-up branch pipe at the secondary expander inlet. After the secondary expander inlet pipeline is warmed up, the same steps are repeated to preheat the tertiary expander inlet pipeline.

[0006] As the capacity of compressed gas energy storage power stations continues to increase, the rated air intake of expanders also gradually increases. Most of the air intake and exhaust pipes of each stage of the expander adopt dual control, that is, each stage of the expander is equipped with two air intake pipes and two exhaust pipes. Due to the influence of the power station layout, the lengths of the two air intake pipes are not exactly the same. Therefore, the warm-up rate of the two pipes is also different. Air intake is only allowed after the temperature of both air intake pipes meets the air intake requirements, which undoubtedly prolongs the warm-up time and increases the air consumption for warm-up.

[0007] In summary, the conventional startup warm-up process is complex, with a long warm-up time and high gas consumption during the warm-up phase. This is especially true for large-capacity dual-inlet units, where the warm-up rates of the two inlet pipes are unbalanced, further increasing the warm-up time and gas consumption. This results in the waste of high-pressure gas in the gas storage tank, seriously affecting the power plant's startup speed and power-to-power conversion efficiency.

[0008] Meanwhile, to prevent high-pressure gas remaining in the pipeline from directly entering the cylinder and causing overspeed of the expander during startup, the high-pressure gas in the pipeline should be released after the expander unit stops. The conventional solution is to use the warm-up branch pipes installed at the inlet of each expander stage as pressure relief pipelines. However, when the generator set is disconnected from the grid due to abnormal operating conditions or when the unit overspeeds, the unit triggers the OPC action and quickly closes the main gas valves and regulating valves at each stage. When the speed drops to around 3000 rpm, the regulating valves need to be reopened to maintain the unit speed at 3000 rpm in order to quickly restore power supply. At this time, relying solely on the conventionally installed warm-up branch pipes for pressure relief cannot release the gas in the pipeline in time, causing the expander unit speed to soar, which seriously affects the safe and stable operation of the unit.

[0009] Therefore, it is necessary to develop an expander start-up warm-up and pressure relief system that effectively reduces the gas consumption during the expander start-up phase, increases the unit's warm-up rate, ensures uniform warm-up rates on both sides of the pipes in a large-capacity unit, and also has overspeed pressure relief protection, while ensuring the safe and stable operation of the unit and having good economic benefits. Utility Model Content

[0010] The primary objective of this invention is to address the problem of unbalanced heating rates of the pipes on both sides during the warm-up process of the expander unit in existing large-capacity compressed gas energy storage power stations. This invention improves the control precision of the unit's warm-up process and further reduces the gas consumption during the warm-up phase.

[0011] The second objective of this invention is to solve the problem that the existing compressed gas energy storage power station expander unit has a large gas consumption during the start-up warm-up period, which affects the power station's electro-electric conversion efficiency. This invention reduces the gas consumption during the start-up phase of the expander unit and improves the power station's electro-electric conversion efficiency.

[0012] The third objective of this invention is to solve the problem of long start-up and warm-up time in the existing compressed gas energy storage power station expander unit start-up system. This invention reduces the start-up time of the expander unit and improves the start-up response rate of the power station during the expansion power generation phase.

[0013] The fourth objective of this invention is to solve the problem of low adjustment accuracy in the control mode of the expander inlet regulating valve during the start-up and low-load stages of existing large-capacity expander units. This invention improves the adjustment accuracy of the expander during start-up and operation.

[0014] The fifth objective of this invention is to solve the problem of untimely pressure relief rate in existing large-capacity expander units. This invention improves the rapid pressure relief capability of the pipeline after the unit's OPC is activated, thereby improving the reliability of the expander unit in maintaining its rated speed and reconnecting to the grid for power generation.

[0015] To achieve the above objectives, the technical solution of this utility model is as follows: a large-capacity compressed gas energy storage power station expander start-up warm-up and pressure relief system, comprising a gas storage tank, n-stage expanders, and n-stage heat exchangers. The gas storage tank is sequentially connected to the first-stage expander via a main shut-off valve and a first-stage heat exchanger. The n-stage expanders are sequentially connected, and a heat exchanger is installed between adjacent expanders. The system is characterized by:

[0016] The heat exchanger outlet is connected to the first inlet of the expander through the first expansion inlet shut-off valve and to the second inlet of the expander through the second expansion inlet shut-off valve. The first outlet and the second outlet of the expander are combined or connected separately to the inlet of the next stage heat exchanger.

[0017] It also includes a start-up warm-up / start-up control valve assembly and an n-stage start-up warm-up / pressure relief system;

[0018] The start-up warm-up / run-up control valve group is connected in parallel with the main shut-off valve. The start-up warm-up / run-up control valve group includes a bypass regulating valve and bypass regulating valve inlet and outlet shut-off valves.

[0019] The start-up warm-up / pressure relief system includes a first warm-up / pressure relief shut-off valve, a second warm-up / pressure relief shut-off valve, a first warm-up / pressure relief regulating valve, and a second warm-up / pressure relief regulating valve; the heat exchanger and the first expansion inlet shut-off valve are sequentially connected to the inlet of the next-stage heat exchanger through the first warm-up / pressure relief shut-off valve and the first warm-up / pressure relief regulating valve; the heat exchanger and the second expansion inlet shut-off valve are sequentially connected to the inlet of the next-stage heat exchanger through the second warm-up / pressure relief shut-off valve and the second warm-up / pressure relief regulating valve.

[0020] The above technical solution also includes an emergency pressure relief system, which is installed at the inlet of the heat exchanger from the second stage to the nth stage. The emergency pressure relief system includes a fast pressure relief valve, which is connected to the heat exchanger inlet pipe.

[0021] In the above technical solution, the quick pressure relief valve is connected to the silencer.

[0022] In the above technical solution, the outlet of the heat exchanger of the first stage is connected to the first inlet of the first stage expander in sequence through the first expansion inlet shut-off valve and the first stage regulating valve, and is connected to the second inlet of the first stage expander in sequence through the second expansion inlet shut-off valve and the second stage regulating valve.

[0023] In the above technical solution, the pipe diameter of the start-up warm-up / run-up control valve group is selected according to the maximum flow rate of the expander warm-up and run-up.

[0024] In the above technical solution, the expander has three stages, the heat exchanger has three stages, and the start-up warm-up / pressure relief system has three stages.

[0025] In the above technical solution, the inlet pipe of the first warm-up / pressure relief shut-off valve is arranged adjacent to the inlet pipe of the first expansion inlet shut-off valve, and the inlet pipe of the second warm-up / pressure relief shut-off valve is arranged adjacent to the inlet pipe of the second expansion inlet shut-off valve.

[0026] The outlet pipes of the first and second warming / pressure relief regulating valves are located near the inlet pipe of the next stage heat exchanger.

[0027] Compared with the prior art, this utility model has the following advantages:

[0028] 1) This utility model adjusts the warming air volume of the two intake pipes of each stage expander by setting a first warming / pressure relief regulating valve and a second warming / pressure relief regulating valve respectively, so as to ensure that the warming rate of the two pipes on both sides is balanced, and that the two intake pipes of different lengths have the same warming rate; it reduces the warming time and warming air consumption, and improves the power plant start-up rate and electro-electric conversion efficiency.

[0029] 2) In emergency operating conditions of the unit, this utility model can quickly release the high-pressure gas in the inlet pipes of the secondary and tertiary expanders through the emergency pressure relief system, thus solving the problem of untimely release of existing relief systems and the risk of overspeed when the unit maintains its rated speed.

[0030] 3) This utility model organically combines the start-up warm-up / start-up control valve group, the start-up warm-up / pressure relief system and the emergency pressure relief system, making it suitable for all operating conditions of the expander in a large-capacity compressed gas energy storage power station.

[0031] 4) This utility model can use the same amount of gas to complete the sequential warm-up of the inlet pipes of multi-stage expanders, reducing the gas consumption for warm-up; and the warm-up gas volume of the two inlet pipes of each stage expander can be adjusted by setting the first warm-up / pressure relief regulating valve and the second warm-up / pressure relief regulating valve respectively, so as to ensure the balance of the warm-up heating rate of the pipes on both sides; for a three-stage expander system, compared with the conventional warm-up system, this utility model can reduce the warm-up gas consumption by 2 / 3, and the more expansion stages there are, the more obvious the gas-saving effect is, which can effectively improve the power plant's electricity-to-electricity conversion efficiency.

[0032] 5) This utility model can simultaneously warm up the inlet pipes of each stage of the expander within the same time, saving the start-up warm-up time; for a three-stage expander system, compared with a conventional warm-up system, it can save 2 / 3 of the warm-up time, and the more expansion stages there are, the more obvious the time-saving effect is, effectively improving the response speed of the power plant during the start-up phase.

[0033] 6) This utility model utilizes the start-up warm-up / run-up control valve group to control the warm-up and run-up air flow during the warm-up and run-up periods, and assists the first-stage regulating valve and the second-stage regulating valve in flow control; for large-capacity expander units, it solves the problem of poor regulation accuracy and control difficulty of the first-stage regulating valve and the second-stage regulating valve during the run-up and low-load stages, and further improves the regulation accuracy. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the structure of this utility model.

[0035] Figure 2 This is a schematic diagram of a conventional expander warm-up system.

[0036] Among them, 100-gas storage tank, 110-main shut-off valve, 200-expander, 210-first expansion inlet shut-off valve, 211-first stage regulating valve, 220-second expansion inlet shut-off valve, 221-second stage regulating valve, 300-heat exchanger, 400-start-up warm-up / surge control valve group, 410-bypass regulating valve, 420-bypass regulating valve inlet and outlet shut-off valve, 500-start-up warm-up / pressure relief system, 510-first warm-up / pressure relief shut-off valve, 520-second warm-up / pressure relief shut-off valve, 530-first warm-up / pressure relief regulating valve, 540-second warm-up / pressure relief regulating valve, 600-emergency pressure relief system, 610-quick pressure relief valve, 620-silencer. Detailed Implementation

[0037] The following detailed description, in conjunction with the accompanying drawings, illustrates the implementation of this utility model. However, these descriptions do not constitute a limitation of the present utility model and are merely illustrative. Furthermore, the advantages of this utility model will become clearer and easier to understand through this explanation.

[0038] Referring to the attached drawings, a large-capacity compressed gas energy storage power station expander start-up warm-up and depressurization system includes a gas storage tank 100, n-stage expanders 200, and n-stage heat exchangers 300. The gas storage tank 100 is connected to the first-stage expander 200 in sequence through a main shut-off valve 110 and the first-stage heat exchanger 300. The n-stage expanders 200 are connected in sequence. A heat exchanger 300 is installed between adjacent expanders 200. The outlet of the heat exchanger 300 is connected to the first inlet of the expander 200 through a first expansion inlet shut-off valve 210 and to the second inlet of the expander 200 through a second expansion inlet shut-off valve 220. The first and second outlets of the expander 200 are combined or connected separately to the inlet of the next stage heat exchanger 300.

[0039] It also includes a start-up warm-up / start-up control valve assembly 400 and an n-stage start-up warm-up / pressure relief system 500;

[0040] The start-up warm-up / run-up control valve group 400 is connected in parallel with the main shut-off valve 110. The start-up warm-up / run-up control valve group 400 includes a bypass regulating valve 410 and bypass regulating valve inlet and outlet shut-off valves 420.

[0041] The start-up warm-up / pressure relief system 500 includes a first warm-up / pressure relief shut-off valve 510, a second warm-up / pressure relief shut-off valve 520, a first warm-up / pressure relief regulating valve 530, and a second warm-up / pressure relief regulating valve 540; the heat exchanger 300 and the first expansion inlet shut-off valve 210 are sequentially connected to the inlet of the next-stage heat exchanger 300 through the first warm-up / pressure relief shut-off valve 510 and the first warm-up / pressure relief regulating valve 530; the heat exchanger 300 and the second expansion inlet shut-off valve 220 are sequentially connected to the inlet of the next-stage heat exchanger 300 through the second warm-up / pressure relief shut-off valve 520 and the second warm-up / pressure relief regulating valve 540.

[0042] It also includes an emergency pressure relief system 600, which is installed at the inlet of the heat exchanger 300 from the second stage to the nth stage. The emergency pressure relief system 600 includes a fast pressure relief valve 610, which is connected to the inlet pipe of the heat exchanger 300.

[0043] The quick-release valve 610 is connected to the silencer 620.

[0044] The outlet of the heat exchanger 300 of the first stage is connected to the first inlet of the expander 200 of the first stage in sequence through the first expansion inlet shut-off valve 210 and the first stage regulating valve 211, and is connected to the second inlet of the expander 200 of the first stage in sequence through the second expansion inlet shut-off valve 220 and the second stage regulating valve 221.

[0045] The pipe diameter of the start-up warm-up / run-up control valve group 400 is selected according to the maximum flow rate of the expander 200 during warm-up and run-up; it does not need to be selected according to the maximum air intake of the expander 200, so as to reduce the valve diameter, improve the flow control accuracy, and reduce the cost of the valve group.

[0046] The expander 200 has three stages, the heat exchanger 300 has three stages, and the start-up warm-up / pressure relief system 500 has three stages.

[0047] The inlet pipe of the first warm-up / pressure relief shut-off valve 510 is located adjacent to the inlet pipe of the first expansion inlet shut-off valve 210, and the inlet pipe of the second warm-up / pressure relief shut-off valve 520 is located adjacent to the inlet pipe of the second expansion inlet shut-off valve 220.

[0048] The outlet pipes of the first warm-up / pressure relief regulating valve 530 and the second warm-up / pressure relief regulating valve 540 are located near the inlet pipe of the next stage heat exchanger 300.

[0049] In actual use, the function of the start-up warm-up / run-up control valve group 400 is to control the flow rate of warm-up air and run-up air during the start-up warm-up and run-up phases; the flow rate of warm-up air and run-up air can be controlled by the opening of the bypass regulating valve 410.

[0050] In the start-up warm-up / pressure relief system 500, the first warm-up / pressure relief shut-off valve 510 and the first warm-up / pressure relief regulating valve 530 control the warm-up rate on the intake A side of the expander 200, while the second warm-up / pressure relief shut-off valve 520 and the second warm-up / pressure relief regulating valve 540 control the warm-up rate on the intake B side of the expander 200. The warm-up rates on the intake A and intake B sides of the expander 200 are balanced by adjusting the opening of the first warm-up / pressure relief regulating valve 530 and the second warm-up / pressure relief regulating valve 540. The function of the start-up warm-up / pressure relief system 500 is to, during the start-up warm-up phase, sequentially heat the warm-up airflow from the gas storage tank 100 through the heat exchangers 300 at each stage, and then heat the expanders at each stage. Simultaneously, the 200 inlet pipe is preheated to reduce preheating gas consumption and save preheating time. After the expander unit stops, the preheating / pressure relief systems 500 at each stage are opened to release the high-pressure gas remaining in the inlet pipes of each expander 200. The inlets of the preheating / pressure relief systems 500 at each stage should be located adjacent to the first expansion inlet shut-off valve 210 and the second expansion inlet shut-off valve 220 of each expander 200, and the outlets should be located as close as possible to the inlet of the next stage heat exchanger 300 to ensure the preheating effect of the pipes before the first expansion inlet shut-off valve 210 and the second expansion inlet shut-off valve 220, while minimizing the impact on the low-temperature pipes between the expander 200 outlet and the heat exchanger 300 inlet.

[0051] In the emergency pressure relief system 600, the functions of the quick-release valve 610 and the silencer 620 are to quickly release the high-pressure gas in the intake pipes of the second-stage expander 200 to the nth-stage expander 200 after the expander 200 triggers the OPC action, and the purpose of the silencer 620 is to reduce the exhaust noise during the rapid release process. The quick-release valve 610 only operates under emergency conditions and does not operate during normal shutdown and release, so as to ensure the sealing of the quick-release valve 610 and improve its service life.

[0052] Taking a three-stage expander 200, a three-stage heat exchanger 300, and a three-stage start-up warm-up / pressure relief system 500 as an example, the operating method of this utility model includes the following working conditions:

[0053] Operating Condition 1, Start-up and Warm-up Phase:

[0054] Open the bypass regulating valve 410 and the bypass regulating valve inlet and outlet shut-off valve 420 of the start-up warm-up / run-up control valve group 400. Control the flow rate of warm-up air through the opening of the bypass regulating valve 410. After being heated by the heat exchanger 300 of the first stage, it is divided into two paths to preheat the pipes before the first expansion inlet shut-off valve 210 and the second expansion inlet shut-off valve 220 of the first expansion unit 200 respectively.

[0055] Open the first warm-up / pressure relief shut-off valve 510 and the first warm-up / pressure relief regulating valve 530, the second warm-up / pressure relief shut-off valve 520 and the second warm-up / pressure relief regulating valve 540 of the first-stage start-up warm-up / pressure relief system 500. The cooled airflow enters the second-stage heat exchanger 300 through the first-stage start-up warm-up / pressure relief system 500. After heating, the airflow is divided into two paths to preheat the pipes before the first expansion inlet shut-off valve 210 and the second expansion inlet shut-off valve 220 of the second-stage expander 200 respectively.

[0056] Open the first warm-up / pressure relief shut-off valve 510 and the first warm-up / pressure relief regulating valve 530, the second warm-up / pressure relief shut-off valve 520 and the second warm-up / pressure relief regulating valve 540 of the secondary start-up warm-up / pressure relief system 500. The cooled airflow enters the tertiary heat exchanger 300 through the secondary start-up warm-up / pressure relief system 500. After heating, the airflow is divided into two paths to preheat the pipes before the first expansion inlet shut-off valve 210 and the second expansion inlet shut-off valve 220 of the tertiary expander 200 respectively.

[0057] Open the first warm-up / pressure relief shut-off valve 510 and the first warm-up / pressure relief regulating valve 530, the second warm-up / pressure relief shut-off valve 520 and the second warm-up / pressure relief regulating valve 540 of the three-stage start-up warm-up / pressure relief system 500, and the cooled airflow is discharged into the atmosphere through the exhaust pipe of the three-stage expander 200.

[0058] Throughout the entire start-up warm-up phase, the same airflow is used to preheat the inlet pipes of each stage of the expander 200. The estimated heating rates of the inlet pipes on the A and B sides of each stage of the expander 200 are controlled by the opening of the first warm-up / pressure relief regulating valve 530 and the second warm-up / pressure relief regulating valve 540 of the corresponding start-up warm-up / pressure relief system 500, respectively, to ensure that the preheating rates of the pipes on both sides remain balanced.

[0059] Operating condition 2, pressure relief after pipe warm-up:

[0060] After the warm-up is completed and before the expander is started, open the first warm-up / pressure relief shut-off valve 510 and the first warm-up / pressure relief regulating valve 530, the second warm-up / pressure relief shut-off valve 520 and the second warm-up / pressure relief regulating valve 540 in the secondary and tertiary start-up warm-up / pressure relief systems 500. The high-pressure gas in the inlet pipes of the secondary and tertiary expanders 200 is released step by step through the start-up warm-up / pressure relief systems 500 to the exhaust pipe of the tertiary expander 200 and then discharged into the atmosphere.

[0061] Operating condition 3, start-up and revving stage:

[0062] Close the first warm-up / pressure relief shut-off valve 510 and the first warm-up / pressure relief regulating valve 530, the second warm-up / pressure relief shut-off valve 520 and the second warm-up / pressure relief regulating valve 540 of each stage of the start-up warm-up / pressure relief system 500. Open the first expansion inlet shut-off valve 210 and the second expansion inlet shut-off valve 220 of the second-stage and third-stage expanders 200. Control the flow rate of the run-up airflow through the small-flow bypass regulating valve 410 of the start-up warm-up / run-up control valve group 400. Adjust the opening of the bypass regulating valve 410 according to the rise rate requirement of the expander 200. At the same time, to ensure the run-up rate requirement, open the main shut-off valve 110 simultaneously. Adjust the speed of the expander 200 through the first expansion inlet shut-off valve 210 and the first-stage regulating valve 211, as well as the second expansion inlet shut-off valve 220 and the second-stage regulating valve 221 set at the inlet of the first-stage expander 200 to complete the run-up operation.

[0063] Operating condition 4, shutdown and pressure relief:

[0064] The normal shutdown and pressure relief process is the same as the pressure relief process after warming up the pipes in step 2. Open the first warming up / pressure relief shut-off valve 510 and the first warming up / pressure relief regulating valve 530, the second warming up / pressure relief shut-off valve 520 and the second warming up / pressure relief regulating valve 540 in the secondary and tertiary start-up warming up / pressure relief systems 500. The high-pressure gas in the inlet pipes of the secondary and tertiary expanders 200 is released step by step through the start-up warming up / pressure relief system 500 to the exhaust pipe of the tertiary expander 200 and then discharged into the atmosphere. The high-pressure gas in the inlet pipe of the primary expander 200 is retained and used as the warming up airflow for the next start-up, saving gas consumption during the start-up phase.

[0065] When the system before the primary heat exchanger 300 or the primary expander 200 needs maintenance, open the primary, secondary, and tertiary start-up warm-up / pressure relief system 500 to release the high-pressure gas in the inlet pipe of the primary expander 200 through the start-up warm-up / pressure relief system 500 of each stage to the exhaust pipe of the tertiary expander 200 and then into the atmosphere.

[0066] Operating condition 5, emergency pressure relief condition:

[0067] When the expander 200 disconnects from the grid due to an emergency or overspeeds, the expander 200 unit triggers the OPC action. To ensure that the expander 200 unit can quickly restore its power generation capacity, the expander 200 unit needs to maintain a speed of 3000 rpm. At this time, the emergency pressure relief system 600 is opened, and the high-pressure gas in the inlet pipes of the secondary expander 200 and the tertiary expander 200 is discharged to the atmosphere through the quick pressure relief valve 610 and the silencer 620, respectively, to ensure that the expander 200 unit does not overspeed.

[0068] In summary, this invention effectively reduces the gas consumption for warming up the expansion tank during the start-up phase and increases the unit's warm-up rate. For a three-stage expansion tank unit, compared with conventional solutions, the gas consumption for warming up can be reduced by more than 60%, and the start-up time can be shortened by more than 60%. At the same time, this invention ensures a uniform warm-up rate for the pipes on both sides of the large-capacity expansion tank unit and also has an overspeed pressure relief function. Under the premise of ensuring the safe and stable operation of the expansion tank unit, it has good economic benefits.

[0069] All other unspecified parts belong to the prior art.

Claims

1. A start-up, warm-up, and depressurization system for an expander in a large-capacity compressed gas energy storage power station, comprising a gas storage tank (100), n-stage expanders (200), and n-stage heat exchangers (300), wherein the gas storage tank (100) is sequentially connected to the first-stage expander (200) via a main shut-off valve (110) and a first-stage heat exchanger (300), the n-stage expanders (200) are sequentially connected, and a heat exchanger (300) is provided between adjacent expanders (200), characterized in that: The outlet of the heat exchanger (300) is connected to the first inlet of the expander (200) through the first expansion inlet shut-off valve (210) and to the second inlet of the expander (200) through the second expansion inlet shut-off valve (220). The first outlet and the second outlet of the expander (200) are combined or connected separately to the inlet of the next stage heat exchanger (300). It also includes a start-up warm-up / start-up control valve assembly (400) and an n-stage start-up warm-up / pressure relief system (500); The start-up warm-up / run-up control valve group (400) is connected in parallel with the main shut-off valve (110). The start-up warm-up / run-up control valve group (400) includes a bypass regulating valve (410) and bypass regulating valve inlet and outlet shut-off valves (420). The start-up warm-up / pressure relief system (500) includes a first warm-up / pressure relief shut-off valve (510), a second warm-up / pressure relief shut-off valve (520), a first warm-up / pressure relief regulating valve (530), and a second warm-up / pressure relief regulating valve (540); the heat exchanger (300) and the first expansion inlet shut-off valve (210) are sequentially connected to the inlet of the next stage heat exchanger (300) through the first warm-up / pressure relief shut-off valve (510) and the first warm-up / pressure relief regulating valve (530); the heat exchanger (300) and the second expansion inlet shut-off valve (220) are sequentially connected to the inlet of the next stage heat exchanger (300) through the second warm-up / pressure relief shut-off valve (520) and the second warm-up / pressure relief regulating valve (540).

2. The large-capacity compressed gas energy storage power station expander start-up warm-up and depressurization system according to claim 1, characterized in that: It also includes an emergency pressure relief system (600), which is installed at the inlet of the heat exchanger (300) from the second stage to the nth stage. The emergency pressure relief system (600) includes a quick pressure relief valve (610), which is connected to the inlet pipe of the heat exchanger (300).

3. The large-capacity compressed gas energy storage power station expander start-up warm-up and depressurization system according to claim 2, characterized in that: The quick-release valve (610) is connected to the silencer (620).

4. The large-capacity compressed gas energy storage power station expander start-up warm-up and depressurization system according to claim 1, characterized in that: The outlet of the heat exchanger (300) of the first stage is connected to the first inlet of the expander (200) of the first stage in sequence through the first expansion inlet shut-off valve (210) and the first stage regulating valve (211), and is connected to the second inlet of the expander (200) of the first stage in sequence through the second expansion inlet shut-off valve (220) and the second stage regulating valve (221).

5. The large-capacity compressed gas energy storage power station expander start-up warm-up and depressurization system according to claim 4, characterized in that: The pipe diameter of the start-up warm-up / run-up control valve group (400) is selected according to the maximum flow rate of the expander (200) during warm-up and run-up.

6. A large-capacity compressed gas energy storage power station expander start-up warm-up and depressurization system according to claim 5, characterized in that: The expander (200) has three stages, the heat exchanger (300) has three stages, and the start-up warm-up / pressure relief system (500) has three stages.

7. The large-capacity compressed gas energy storage power station expander start-up warm-up and depressurization system according to claim 6, characterized in that: The inlet pipe of the first warm-up / pressure relief shut-off valve (510) is located adjacent to the inlet pipe of the first expansion inlet shut-off valve (210), and the inlet pipe of the second warm-up / pressure relief shut-off valve (520) is located adjacent to the inlet pipe of the second expansion inlet shut-off valve (220). The outlet pipes of the first warm-up / pressure relief regulating valve (530) and the second warm-up / pressure relief regulating valve (540) are located close to the inlet pipe of the next stage heat exchanger (300).

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