Quick starting system and method for compressed air energy storage multi-stage expansion machine

Abstract

The invention discloses a compressed air energy storage multi-stage expansion machine quick starting system and method. The compressed air energy storage multi-stage expansion machine quick starting system comprises multi-stage expansion machines which are sequentially connected in series and a main air inlet pipeline connected to the first-stage expansion machine. The main air inlet module is used for supplying and adjusting air flow to the multi-stage expansion machine in a normal operation mode; the last-stage priority starting module is used for converting a high-pressure gas source into low-pressure large-flow mixed gas flow suitable for being driven by the expansion machine in the initial starting stage, and the converted mixed gas flow bypasses the previous expansion machine and directly drives the last-stage expansion machine to rotate and accelerate; the multi-stage preheating module is used for guiding part of gas to carry out reverse-sequence preheating on the previous-stage expansion machines, reverse airflow serves as starting damping and is further used for assisting in stabilizing the rotating speed, the gas completing the preheating task is exhausted through an exhaust valve, speed increasing and reverse-sequence preheating are carried out in parallel, the starting time is greatly shortened, and the starting efficiency is improved. And the starting time of the unit from the cold state to the grid-connected condition is reduced to the minute level.

Description

Technical Field

[0001] This invention relates to the field of energy storage technology, and in particular to a rapid start-up system and method for a multi-stage expander for compressed air energy storage. Background Technology

[0002] Compressed air energy storage technology, which releases high-pressure air during peak electricity demand periods to drive an expander for power generation, is an effective means of achieving grid peak shaving and large-scale energy storage. Expander units typically consist of multiple stages connected in series, where high-pressure air expands and depressurizes stage by stage to drive the generator.

[0003] The compressed air released from the gas storage chamber is at extremely high pressure. During the initial startup phase of the expander, especially in the stage of driving the generator to overcome inertial resistance and gradually increase speed, the actual required airflow pressure and flow rate are relatively small. High-pressure airflow in the initial startup phase may cause the expander speed to surge rapidly, making it difficult to achieve a smooth and controlled acceleration process, thus leading to safety risks such as unit vibration and bearing impact. To adapt to the low flow rate requirement during startup, traditional methods may require significant throttling, resulting in huge pressure losses and wasting valuable high-pressure air energy. Traditional startup methods also have long and uneven heat transfer paths, causing startup times that cannot meet the grid's demand for fast-response power.

[0004] Therefore, there is an urgent need in this field for an innovative startup strategy that can effectively solve the complex technical challenges of precise speed control, efficient energy utilization, and rapid and uniform preheating under high-voltage and low-flow startup conditions, and efficiently integrate the preheating and speed-up processes to fundamentally shorten the total time from cold state to grid-connected power generation. Summary of the Invention

[0005] Therefore, the technical problem to be solved by this invention is: how to solve the problems of precise speed control, efficient energy utilization, and rapid and uniform preheating under high pressure and low flow start-up.

[0006] The above-mentioned technical problems are solved by the following technical solution: The present invention proposes a rapid start-up system for a multi-stage expander with compressed air energy storage, which includes a multi-stage expander connected in series and a main air intake pipeline connected to the first-stage expander;

[0007] The main intake module is used to supply and regulate airflow to the multi-stage expander during normal operation.

[0008] The final stage priority start module is used to convert the high-pressure gas source into a low-pressure, high-flow mixed gas flow suitable for the expander drive in the initial stage of startup. The converted mixed gas flow bypasses the preceding expander and directly drives the last stage expander to rotate and accelerate.

[0009] The multi-stage preheating module is used to guide a portion of the gas to preheat the preceding stages of the expander in reverse order. The reverse airflow acts as a starting damper and also helps to stabilize the speed. The gas that has completed the preheating task is discharged through the exhaust valve.

[0010] The central control module is connected to each valve actuator and unit status sensor. It stores and executes preset control algorithms to coordinate and control the entire startup process.

[0011] In a preferred embodiment of the compressed air energy storage multi-stage expander rapid start system of the present invention: the main air intake module includes a main air intake pipeline connected to the high-pressure air source outlet, a main air intake valve and a main regulating valve disposed on the main air intake pipeline;

[0012] The main intake valve is used to control the opening and closing state of the main intake pipeline, and the main regulating valve is used to supply and regulate the airflow to the multi-stage expander in normal operating mode.

[0013] In a preferred embodiment of the compressed air energy storage multi-stage expander rapid start system of the present invention: the final stage priority start module includes a bypass pipeline led out from the main air intake pipeline, a start control valve, an ejector and a final stage start valve arranged sequentially on the bypass pipeline;

[0014] The opening and closing state of the final stage start valve can control the airflow in the bypass pipeline to enter the inlet of the final stage expander.

[0015] In a preferred embodiment of the compressed air energy storage multi-stage expander rapid start-up system of the present invention: the jet is used to convert the high-pressure air source into a low-pressure, high-flow mixed airflow suitable for expanding machine drive in the initial stage of start-up, so that the mixed airflow can bypass the preceding expander and directly drive the last stage expander to rotate and accelerate.

[0016] In a preferred embodiment of the compressed air energy storage multi-stage expander rapid start-up system of the present invention: the multi-stage preheating module includes a preheating valve disposed at the outlet of the intermediate stage expander and an exhaust valve disposed on the inlet pipe of the first stage expander;

[0017] By opening the preheating valve, a portion of the gas can be guided to preheat the preceding stages of the expander in reverse order.

[0018] In a preferred embodiment of the compressed air energy storage multi-stage expander rapid start-up system of the present invention: the gas undergoing reverse preheating can act as a start-up damper to help stabilize the rotational speed, and the gas that has completed the preheating task is discharged through the exhaust valve.

[0019] To solve the above-mentioned technical problems, the present invention also proposes a rapid start-up method for a compressed air energy storage multi-stage expander, which is applied to a rapid start-up system for a compressed air energy storage multi-stage expander. The method further includes, when the system is in a cold state, confirming that the main regulating valve is in a closed state through the central control module, and then issuing a start-up command through the central control module.

[0020] After receiving the start command, the central control module opens the final-level priority start module and the multi-level preheating module;

[0021] The high-pressure air is mixed into a low-pressure, high-flow mixed airflow through the final stage priority start module;

[0022] A portion of the gas is preheated by being guided to flow in the opposite direction through the preceding expander via a multi-stage preheating module.

[0023] The central control module continuously monitors the generator speed and the temperature of each stage of the expander.

[0024] Once the rotational speed reaches the rated value and the temperature of each stage of the expander reaches the preset temperature threshold, the control unit of the central control module executes the mode switching program to the conventional series expansion power generation mode.

[0025] In a preferred embodiment of the rapid start-up method for a multi-stage compressed air energy storage expander described in this invention: high-pressure air enters the ejector via a start-up control valve;

[0026] The jet injector converts the high-pressure, low-flow working fluid into a low-pressure, high-flow mixed airflow. This airflow acts on the last-stage expander through the final-stage start-up valve, driving the last-stage expander and generator to start rotating.

[0027] In a preferred embodiment of the rapid start-up method for a multi-stage compressed air energy storage expander described in this invention: the central control module collects the generator speed signal in real time and uses the speed signal as the process variable of the PID controller;

[0028] The controller calculates and outputs a control signal based on the deviation from the preset speed-time curve, and precisely adjusts the opening of the start control valve and the final stage start valve so that the generator speed increases strictly according to the preset smooth curve.

[0029] In a preferred embodiment of the rapid start-up method for a multi-stage expander with compressed air energy storage described in this invention: after the preheating valve is opened, a portion of the gas diverted from the high-pressure air source enters the outlet side of the intermediate nth stage expander in reverse direction, and continues to flow in reverse direction through the first stage expander.

[0030] During the process of the gas flowing in the opposite direction through the first-stage expander, it undergoes sufficient heat exchange with the internal components of the expander, and is uniformly preheated. The preheated gas is finally discharged from the system through the exhaust valve.

[0031] The beneficial effects of this invention are: the speed-up and reverse preheating are carried out in parallel, which greatly shortens the start-up time and reduces the start-up time of the unit from cold state to grid connection condition to the minute level.

[0032] By converting high-pressure gas into low-pressure, high-flow gas through an ejector, precise control under high-pressure, low-flow startup is achieved, solving the problem of speed loss and energy waste that may occur when the high-pressure source directly acts on the expander during the initial startup phase.

[0033] The reverse preheating method not only improves the heat transfer efficiency and uniformity of the preheating gas, but also helps stabilize the acceleration process due to its reverse damping effect. At the same time, it increases the overall airflow during startup, which has a synergistic effect on improving speed control accuracy and preheating effect. Attached Figure Description

[0034] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments of the present invention will be briefly described below. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention. Wherein:

[0035] Figure 1 A schematic diagram of the rapid start-up system for a multi-stage compressed air energy storage expander is shown.

[0036] Figure 2 A flowchart of the module flow chart for a rapid start-up system for a multi-stage expander with compressed air energy storage is shown.

[0037] In the diagram: 1. High-pressure air source; 2. Heat exchanger; 3. Main intake valve; 4. Main regulating valve; 5. First-stage expander; 6. nth-stage expander; 7. Last-stage expander; 8. Generator; 9. Start-up control valve; 10. Ejector; 11. Preheating valve; 12. Last-stage start-up valve; 13. Exhaust valve; 100. Main intake module; 200. Last-stage priority start-up module; 300. Multi-stage preheating module; 400. Central control module. Detailed Implementation

[0038] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0039] The terminology used in this invention is that which is currently widely used in the art in consideration of the function of the invention; however, these terms may vary according to the intent of those skilled in the art, precedent, or new technology in the art. Furthermore, specific terms may be chosen by the applicant, and in such cases, their detailed meanings will be described in the detailed description of the invention. Therefore, the terms used in this specification should not be construed as simple names, but rather based on their meanings and the overall description of the invention.

[0040] Reference Figure 2 This embodiment provides a rapid start-up system for a multi-stage compressed air energy storage expander, including a multi-stage expander connected in series and a main air intake pipeline connected to the first-stage expander;

[0041] The main intake module 100 is used to supply and regulate airflow to the multi-stage expander in normal operating mode;

[0042] The final stage priority start module 200 is used to convert the high-pressure gas source into a low-pressure, high-flow mixed gas flow suitable for the expander drive at the initial stage of startup. The converted mixed gas flow bypasses the preceding expander and directly drives the final stage expander 7 to rotate and increase speed.

[0043] The multi-stage preheating module 300 is used to guide part of the gas to preheat the preceding stages of the expander in reverse order. The reverse airflow acts as a starting damper and also helps to stabilize the speed. The gas that has completed the preheating task is discharged through the exhaust valve 13.

[0044] The central control module 400 is connected to each valve actuator and unit status sensor. It stores and executes preset control algorithms to coordinate and control the entire startup process.

[0045] In some implementations, refer to Figure 1 The main intake module 100 includes a main intake pipeline connected to the outlet of the high-pressure air source 1, a main intake valve 3 and a main regulating valve 4 disposed on the main intake pipeline;

[0046] The main intake valve 3 is used to control the opening and closing state of the main intake pipeline, and the main regulating valve 4 is used to supply and regulate the airflow to the multi-stage expander in normal operation mode.

[0047] Specifically, the final stage priority start module 200 includes a bypass pipeline led out from the main intake pipeline, a start control valve 9, an ejector 10 and a final stage start valve 12 sequentially arranged on the bypass pipeline;

[0048] The opening and closing state of the final stage start valve 12 can control the airflow of the bypass pipeline into the inlet of the final stage expander 7.

[0049] Furthermore, the jet injector 10 is used to convert the high-pressure gas source into a low-pressure, high-flow-rate mixed gas flow suitable for the expander drive at the initial stage of startup, so that the mixed gas flow can bypass the preceding expander and directly drive the final stage expander 7 to rotate and increase speed.

[0050] It should be noted that by converting the high-pressure gas source into a low-pressure, high-flow gas source through the ejector 10, precise control under high-pressure, low-flow start-up is achieved, which solves the problem of speed control failure and energy waste that may be caused by the high-pressure source acting directly on the expander in the initial stage of start-up.

[0051] Furthermore, the multi-stage preheating module 300 includes a preheating valve 11 located at the outlet of the intermediate stage expander and an exhaust valve 13 located on the inlet pipe of the first stage expander 5; by opening the preheating valve 11, a portion of the gas can be guided to perform reverse preheating of the preceding stages of expanders.

[0052] Furthermore, the gas undergoing reverse preheating can act as a starting damper to help stabilize the rotational speed, and the gas that has completed the preheating task can be discharged through the exhaust valve 13.

[0053] It should be noted that the reverse preheating method not only improves the heat transfer efficiency and uniformity of the preheating gas, but also the reverse damping effect it generates helps stabilize the acceleration process. At the same time, it increases the overall airflow during startup, which has a synergistic effect on improving speed control accuracy and preheating effect.

[0054] This embodiment provides a rapid start-up method for a compressed air energy storage multi-stage expander, applied to a rapid start-up system for a compressed air energy storage multi-stage expander, and also includes...

[0055] When the system is cold, the central control module confirms that the main regulating valve 4 is closed, and then issues a start command through the central control module.

[0056] After receiving the start command, the central control module 400 opens the final priority start module 200 and the multi-stage preheating module 300;

[0057] The final stage priority start module 200 mixes high-pressure air into low-pressure, high-flow mixed airflow.

[0058] A portion of the gas is preheated by the multi-stage preheating module 300, which guides a portion of the gas to flow in the opposite direction through the preceding expander.

[0059] The central control module continuously monitors the generator speed and the temperature of each stage of the expander.

[0060] Once the rotational speed reaches the rated value and the temperature of each stage of the expander reaches the preset temperature threshold, the control unit of the central control module executes the mode switching program to the conventional series expansion power generation mode.

[0061] Specifically, the ejector 10 converts the high-pressure, low-flow working fluid into a low-pressure, high-flow mixed airflow. This airflow acts on the last-stage expander 7 through the final-stage start-up valve 12, driving the last-stage expander 7 and the generator 8 to start rotating.

[0062] Furthermore, the central control module 400 collects the speed signal of the generator 8 in real time and uses the speed signal as the process variable of the PID controller.

[0063] The controller calculates and outputs a control signal based on the deviation from the preset speed-time curve, and precisely adjusts the opening of the start control valve 9 and the final stage start valve 12 so that the speed of the generator 8 increases strictly according to the preset smooth curve.

[0064] Furthermore, some of the gas diverted from the high-pressure air source 1 enters the outlet side of the intermediate n-stage expander 6 in reverse after the preheating valve 11 is opened, and continues to flow in reverse through the first-stage expander 5; it should be noted that the intermediate-stage expander is the n-stage expander 6.

[0065] During the process of the gas flowing in the opposite direction through the first-stage expander 5, it undergoes sufficient heat exchange with the internal components of the expander, and is uniformly preheated. The preheated gas is finally discharged from the system through the exhaust valve 13.

[0066] Working steps: S1, Startup mode initialization.

[0067] Specifically, when the system is cold, the central control module 400 confirms that the main regulating valve 4 is closed. Upon receiving the start command, the control unit opens the start control valve 9, the preheating valve 11, the final stage start valve 12, and the exhaust valve 13. High-pressure air is guided to the final stage priority start subsystem and the multi-stage preheating subsystem.

[0068] S2, Parallel acceleration and reverse preheating.

[0069] Specifically, the central control module 400 performs the following two parallel control tasks:

[0070] a. Speed ​​Increase Control: Drives the final stage expander 7 and the connected generator 8 to increase speed. High-pressure air enters the ejector 10 through the start control valve 9, where it mixes with the surrounding air to form a mixed airflow with moderate pressure and a large flow rate. This airflow passes through the final stage start valve 12 and impacts the final stage expander 7 at high speed, driving it and the generator 8 to rotate and increase speed. The central control module 400 adopts a proportional-integral-derivative (PID) control algorithm, using the actual speed feedback from the generator 8 speed sensor as the process variable (PV) and the preset speed increase curve (the target speed value that changes over time) as the setpoint (SP). The algorithm outputs adjustment signals to control the opening of the start control valve 9 and the final stage start valve 12, ensuring that the speed increase rate of the generator 8 is strictly maintained within the set range, avoiding speed runaway or fluctuation.

[0071] b. Reverse Preheating Control: A portion of the gas is guided to flow in the reverse direction through the preceding expander for preheating. The gas enters the intermediate expander via preheating valve 11, and then flows in the reverse direction through the first-stage expander 5. During this process, the airflow efficiently transfers heat to the expander body. Simultaneously, this reverse airflow provides some reverse damping to the forward driving force during initial startup, helping to smooth the acceleration curve and prevent speed overshoot. Furthermore, this reverse airflow is discharged through exhaust valve 13 at the inlet of the first-stage expander 5, increasing the total airflow during startup and further improving the preheating effect and speed stability. Similarly, a PID control algorithm can be used, with the temperature sensor value on the preceding expander body as the process variable and the preset lower limit of the operating temperature as the setpoint. The algorithm outputs an adjustment signal to control the opening of preheating valve 11 and exhaust valve 13 to maintain the preheating gas flow rate and exhaust volume, ensuring that the temperature reaches the setpoint within a specified time.

[0072] S3, Switching between operating modes.

[0073] Specifically, the central control module 400 continuously monitors the speed of generator 8 and the temperature of each stage of expander.

[0074] When the speed reaches the rated value (e.g., 3000 rpm) and the temperature of each stage expander reaches the preset temperature threshold, the control unit executes the mode switching procedure: closes the start control valve 9, preheat valve 11, final stage start valve 12 and exhaust valve 13; then, opens the main intake valve 3 and main regulating valve 4, so that the high-pressure air switches to the normal operating path and flows through each stage expander in sequence. At this time, the unit is ready to be connected to the grid.

[0075] Finally, it should be noted that the methods and devices described in detail above are merely embodiments, and those skilled in the art can modify these embodiments in different ways as long as they do not depart from the scope of the present invention.

Claims

1. A rapid start-up system for a multi-stage compressed air energy storage expander, characterized in that: This includes a series of multi-stage expanders connected in series and a main intake pipe connected to the first-stage expander; The main intake module (100) is used to supply and regulate airflow to the multi-stage expander in normal operating mode; The final stage priority start module (200) is used to convert the high-pressure gas source into a low-pressure, high-flow mixed gas flow suitable for the expander drive in the initial stage of startup. The converted mixed gas flow bypasses the preceding expander and directly drives the last stage expander (7) to rotate and speed up. The multi-stage preheating module (300) is used to guide part of the gas to preheat the preceding stages of the expander in reverse order. The reverse airflow is used as a starting damping and also to help stabilize the speed. The gas that has completed the preheating task is discharged through the exhaust valve (13). The central control module (400) is connected to each valve actuator and unit status sensor. It stores and executes preset control algorithms to coordinate and control the entire startup process.

2. The rapid start-up system for a multi-stage compressed air energy storage expander according to claim 1, characterized in that: The main intake module (100) includes a main intake pipeline connected to the outlet of the high-pressure air source (1), a main intake valve (3) and a main regulating valve (4) disposed on the main intake pipeline; The main intake valve (3) is used to control the opening and closing state of the main intake pipeline, and the main regulating valve (4) is used to supply and regulate the airflow to the multi-stage expander in normal operating mode.

3. The rapid start-up system for a multi-stage compressed air energy storage expander according to claim 2, characterized in that: The final stage priority start module (200) includes a bypass pipeline led out from the main intake pipeline, a start control valve (9), an ejector (10) and a final stage start valve (12) sequentially arranged on the bypass pipeline; The opening and closing state of the final stage start valve (12) can control the airflow of the bypass pipeline to enter the inlet of the last stage expander (7).

4. The rapid start-up system for a multi-stage compressed air energy storage expander according to claim 3, characterized in that: The jet injector (10) is used to convert the high-pressure gas source into a low-pressure, high-flow mixed gas flow suitable for the expander drive at the initial stage of startup, so that the mixed gas flow can bypass the preceding expander and directly drive the last stage expander (7) to rotate and increase speed.

5. The rapid start-up system for a multi-stage compressed air energy storage expander according to claim 4, characterized in that: The multi-stage preheating module (300) includes a preheating valve (11) located at the outlet of the intermediate stage expander and an exhaust valve (13) located on the inlet pipe of the first stage expander (5). By opening the preheating valve (11), a portion of the gas can be guided to preheat the preceding stages of the expander in reverse order.

6. The rapid start-up system for a multi-stage compressed air energy storage expander according to claim 5, characterized in that: The gas that is preheated in reverse order can act as a starting damper to help stabilize the rotation speed, and the gas that has completed the preheating task can be discharged through the exhaust valve (13).

7. A rapid start-up method for a compressed air energy storage multi-stage expander, characterized in that: The rapid start-up system for a multi-stage compressed air energy storage expander, applicable to any one of claims 1 to 6, further includes: When the system is cold, the central control module confirms that the main regulating valve (4) is closed, and then the central control module issues a start command. After receiving the start command, the central control module opens the final priority start module (200) and the multi-stage preheating module (300); The high-pressure air is mixed into a low-pressure, high-flow-rate mixed airflow through the final stage priority start module (200); A portion of the gas is preheated by being guided to flow in the opposite direction through the preceding expander via a multi-stage preheating module (300). The central control module (400) continuously monitors the generator (8) speed and the temperature of each stage of the expander; Once the rotational speed reaches the rated value and the temperature of each stage of the expander reaches the preset temperature threshold, the control unit of the central control module executes the mode switching program to the conventional series expansion power generation mode.

8. The rapid start-up method for a multi-stage compressed air energy storage expander according to claim 7, characterized in that: High-pressure air enters the ejector (10) through the start-up control valve (9); The jet injector (10) converts the high-pressure, low-flow working fluid into a low-pressure, high-flow mixed airflow. This airflow acts on the last stage expander (7) through the final stage start valve (12), driving the last stage expander (7) and the generator (8) to start rotating.

9. The rapid start-up method for a multi-stage compressed air energy storage expander according to claim 8, characterized in that: The central control module collects the speed signal of the generator (8) in real time and uses the speed signal as the process variable of the PID controller; The controller calculates and outputs a control signal based on the deviation from the preset speed-time curve, and precisely adjusts the opening of the start control valve (9) and the final stage start valve (12) so that the generator (8) speed increases strictly according to the preset smooth curve.

10. The rapid start-up method for a multi-stage compressed air energy storage expander according to claim 9, characterized in that: After the preheating valve (11) is opened, part of the gas diverted from the high-pressure air source (1) enters the outlet side of the intermediate nth stage expander (6) in reverse direction and continues to flow in reverse through the first stage expander (5). During the process of the gas flowing in the reverse direction through the first-stage expander (5), it undergoes sufficient heat exchange with the internal components of the expander and is uniformly preheated. The preheated gas is finally discharged from the system through the exhaust valve (13).

Images