A step-by-step control system for a super-high compression ratio multi-stage ejector

Abstract

The embodiment of the application discloses a step-by-step injection control system of a super-high compression ratio multi-stage injection device, which comprises a monitoring module, a control module, a plurality of valves and a multi-stage injector. The multi-stage injector adopts a series layout, and the outlet of a front-stage injector is connected with the inlet of a rear-stage injected fluid, so as to realize step-by-step pressurization. The multi-stage injector comprises a fixed first-stage injector and an adjustable injector provided with an adjusting cone mechanism. The injected fluid inlet of the first-stage injector is used for receiving the injected fluid, and the working fluid inlet of each stage of the injector is used for receiving the working fluid. The outlet of the last-stage injector is used for outputting qualified mixed fluid, so as to realize the back injection of the injected fluid in the qualified mixed fluid. The monitoring module collects the actual pressure and the adjusting cone position of a plurality of preset positions in real time. The control module generates a control signal according to the deviation between the actual pressure and the target pressure or based on the system operation mode, so as to control the adjusting valve opening degree and the adjusting cone position.

Description

Technical Field

[0001] This application relates to the field of internal combustion engine fluid supercharging, and relates to, but is not limited to, a step-by-step ejector control system for an ultra-high compression ratio multi-stage ejector device. Background Technology

[0002] In the field of internal combustion engine fluid supercharging, ejector technology is used to eject and pressurize low-pressure airflow in order to improve engine intake efficiency or achieve exhaust gas recirculation. Due to the high compression ratio requirements that are difficult to achieve with a single-stage ejector, multi-stage ejectors connected in series are used for step-by-step supercharging to achieve efficient mixing and pressurization of fluids at different pressure levels within the internal combustion engine system.

[0003] In existing technologies, multi-stage ejectors typically consist of ejectors with fixed geometric dimensions. The operation and regulation of these fixed ejectors rely on regulating valves installed on the inlet or outlet pipes of each stage. By controlling the opening of these regulating valves, the fluid pressure input to the ejector is changed, thereby achieving a rough adjustment of the overall system operating state.

[0004] However, this control method centered on regulating valves has the following problems when dealing with complex operating conditions such as system start-up and shutdown and large fluctuations in the pressure of the input fluid: poor safety during system start-up and shutdown, difficulty in flexibly adjusting the pressure of the input fluid, and difficulty in achieving coordinated control between multiple valves. Summary of the Invention

[0005] In view of this, embodiments of this application provide a step-by-step ejection control system for an ultra-high compression ratio multi-stage ejector device, which at least solves the problem of inaccurate fluid flow regulation under varying operating conditions caused by reliance on regulating valves.

[0006] The technical solution of this application embodiment is implemented as follows:

[0007] This application provides a step-by-step ejection control system for a multi-stage ejector device with an ultra-high compression ratio. The system includes a monitoring module, a control module, multiple valves, and a multi-stage ejector. Each stage of the multi-stage ejector is connected in series, with the outlet of the previous stage ejector connected to the inlet of the ejected fluid of the next stage ejector to achieve step-by-step pressurization. The multi-stage ejector includes a fixed first-stage ejector and an adjustable ejector with an adjusting cone mechanism. The ejected fluid inlet of the first-stage ejector is used to receive the ejected fluid, the working fluid inlet of each stage ejector is used to receive the working fluid, and the outlet of the last stage ejector is used to output a compliant mixed fluid to achieve the reinjection of the ejected fluid in the compliant mixed fluid. The system includes:

[0008] The monitoring module is used to monitor pressure and position parameters; the pressure and position parameters include: the actual pressure of the system fluid passing through multiple preset positions of the system, and the actual adjustment cone position corresponding to each of the adjustable ejectors; the monitored pressure and position parameters are sent to the control module; the system fluid includes any one of the working fluid, the ejected fluid, and the mixed fluid;

[0009] The control module is used to determine the target pressure of the system fluid passing through each of the preset positions;

[0010] The control module is further configured to receive each of the pressure and position parameters; generate a control signal for the corresponding valve based on the pressure deviation between each actual pressure and the corresponding target pressure, or based on the operating mode of the system; and generate a drive signal for the corresponding adjusting cone mechanism based on the actual pressure of each adjustable ejector and the actual position of the corresponding adjusting cone; send each of the control signals to the corresponding valve; and send each of the drive signals to the corresponding adjusting cone mechanism.

[0011] Each of the valves is configured to receive a corresponding control signal and, based on each control signal, adjust the opening degree of the corresponding valve.

[0012] Each of the aforementioned adjusting cone mechanisms is used to receive the corresponding drive signal, and, based on the drive signal, adjust the position of the corresponding adjusting cone after adjusting the valve corresponding to the adjustable ejector.

[0013] The beneficial effects of the technical solutions provided in this application include at least the following:

[0014] This application utilizes a monitoring module to monitor the pressure of the system fluid and the position of the regulating cone at multiple preset locations in real time, providing a real-time data foundation for the control module. The control module generates valve control signals based on the pressure deviation obtained from the real-time monitoring or according to the system operating mode, and combines this with the regulating cone position to generate drive signals. The sequential series connection of the multi-stage ejectors improves the system's response speed. Through the coordinated action of multiple valves and the regulating cone mechanism based on control and drive signals, the system can quickly stabilize and maintain anti-interference capabilities when dealing with working pressure fluctuations. It also achieves flow tracking and dynamic balance between each stage of the ejector when the flow rate of the natural gas to be recovered changes, significantly improving the system's operational efficiency. This application improves the system's regulation accuracy of the working fluid under varying operating conditions. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0016] Figure 1 A structural diagram of a staged ejection control system for an ultra-high compression ratio multi-stage ejector device provided in this application embodiment;

[0017] Figure 2 A detailed structural diagram of the system provided in the embodiments of this application;

[0018] Figure 3 A module connection diagram of the system provided in the embodiments of this application;

[0019] Figure 4 Performance diagram of the adjustable ejector of the system provided in the embodiments of this application;

[0020] Figure 5 A flowchart illustrating the start-stop pressure control of the system provided in this application embodiment;

[0021] Figure 6 The control structure diagram of the system provided in the embodiments of this application;

[0022] Figure 7 A flow chart of the system provided in the embodiments of this application for flow tracking control;

[0023] Figure 8 A flowchart illustrating the pressure limiting process of the system provided in this application embodiment;

[0024] Figure 9 A schematic diagram illustrating the impact of flow tracking control on system performance during pipeline pressure fluctuations, provided in an embodiment of this application.

[0025] Figure 10 This is a schematic diagram illustrating the impact of flow tracking control on system performance when the flow rate of the natural gas to be recovered changes, as provided in the embodiments of this application. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. The following embodiments are used to illustrate this application, but are not intended to limit the scope of this application. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0027] In the following description, references are made to “some embodiments,” which describe a subset of all possible embodiments. However, it is understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0028] It should be noted that the terms "first, second, and third" used in the embodiments of this application are merely to distinguish similar objects and do not represent a specific ordering of objects. It is understood that "first, second, and third" can be interchanged in a specific order or sequence where permitted, so that the embodiments of this application described herein can be implemented in an order other than that illustrated or described herein.

[0029] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which the embodiments of this application pertain. It should also be understood that terms such as those defined in general dictionaries should be understood to have a meaning consistent with their meaning in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless specifically defined as herein.

[0030] This application provides a step-by-step ejection control system 100 for a multi-stage ejector device with an ultra-high compression ratio. Figure 1 A structural diagram of a staged ejection control system for an ultra-high compression ratio multi-stage ejector device provided in this application embodiment is shown below. Figure 1 As shown, the system 100 includes at least: a monitoring module 110, a control module 120, multiple valves 130, and a multi-stage ejector 140; each stage of the multi-stage ejector 140 is connected in series, and the outlet of the previous stage ejector is connected to the inlet of the ejected fluid of the next stage ejector to achieve step-by-step pressurization; the multi-stage ejector 140 includes a fixed first-stage ejector and an adjustable ejector with an adjusting cone mechanism, the ejected fluid inlet of the first-stage ejector is used to receive the ejected fluid, the working fluid inlet of each stage ejector is used to receive the working fluid, and the outlet of the last stage ejector is used to output the compliant mixed fluid to achieve the reinjection of the ejected fluid in the compliant mixed fluid; the system includes:

[0031] The monitoring module 110 is used to monitor pressure and position parameters; the pressure and position parameters include: the actual pressure of the system fluid passing through multiple preset positions of the system, and the actual adjustment cone position corresponding to each of the adjustable ejectors; the monitored pressure and position parameters are sent to the control module; the system fluid includes any one of the working fluid, the ejected fluid, and the mixed fluid.

[0032] The monitoring module may include a pressure sensor for monitoring system fluid pressure and a position sensor for detecting the position of the adjusting cone in the adjustable ejector. The position sensor may be a linear variable differential transformer or a magnetostrictive sensor.

[0033] Figure 1 In this application, the connection between the monitoring module, the control module, and the multi-stage ejector is merely an example and does not represent a limitation on the specific connection relationship between the monitoring module, the control module, and the multi-stage ejector. The number of adjustable ejectors in this application is greater than or equal to one; that is, n is an integer greater than or equal to two.

[0034] The setup of multiple preset locations must ensure that the data monitored by the monitoring module can serve the system's control logic and safety diagnostics. Multiple preset locations can be selected from key nodes that have a decisive impact on system performance and safety; that is, monitoring points are deployed at corresponding locations for each core variable to achieve feedback and control. The setup of multiple preset locations must adhere to the principle of diagnostics, enabling rapid fault location by comparing the input and output pressures between multiple ejector stages. For example, if the outlet pressure of the first-stage ejector is normal while the outlet pressure of the second-stage ejector is abnormal, the fault can be located in the second-stage ejector.

[0035] For example, by setting up monitoring points at the working fluid inlet of each ejector, the working fluid pressure driving each ejector can be monitored in real time. The working fluid pressure of each ejector is a key basis for calculating the ejection coefficient, evaluating the working efficiency of the current stage, and carrying out coordinated control.

[0036] The control module 120 is used to determine the target pressure of the system fluid passing through each of the preset positions;

[0037] The control module 120 is further configured to receive each of the pressure and position parameters; generate a control signal for the corresponding valve based on the pressure deviation between each actual pressure and the corresponding target pressure, or based on the operating mode of the system; and generate a drive signal for the corresponding adjusting cone mechanism based on the actual pressure of each adjustable ejector and the actual position of the corresponding adjusting cone; send each of the control signals to the corresponding valve; and send each of the drive signals to the corresponding adjusting cone mechanism.

[0038] The control module is implemented using a programmable logic controller (PLC), a distributed control system, or an industrial computer. Its operation relies on its built-in control algorithm. The control module receives the actual pressure at each preset position and the actual position parameters of each regulating cone from the monitoring module, and then uses the control algorithm to calculate the control signals for each regulating valve and the drive signals for each regulating cone.

[0039] The system operates in four modes: startup, shutdown, normal operation, and safety. Startup mode uses a preset sequence of gradual pressurization to ensure a smooth transition from standby to operation. Normal operation mode uses real-time pressure deviation to coordinate the adjustment of valves and regulating cones to maintain stable system outlet pressure. Shutdown mode executes an orderly shutdown sequence, cutting off the working fluid input and releasing residual pressure to ensure a safe and complete system shutdown. Safety mode, in the event of overpressure, underpressure, or other serious faults or danger signals, quickly brings the system to a safe state to prevent accidents.

[0040] Each preset position corresponds to a different target pressure. For example, the target pressure set at the inlet of the first-stage ejector should be greater than the target pressure set at the outlet of the first-stage ejector. Correspondingly, the target pressure set at the outlet of the first-stage ejector should be less than the target pressure set at the outlet of the second-stage ejector, in order to achieve progressive pressurization.

[0041] Each preset position corresponds to the actual pressure being monitored. The difference between the actual pressure and the target pressure is the pressure deviation at the current position. The threshold for the pressure deviation at each position can be the same.

[0042] Each of the plurality of valves 130 is configured to receive a corresponding control signal and, based on each control signal, adjust the opening degree of the corresponding valve.

[0043] A valve is a device that receives control signals and changes its opening degree to control the flow of fluid, either by opening or closing it. Types of valves include regulating valves, gate valves, and ball valves.

[0044] The valve opening is continuously adjusted by the control signal output by the control module, thereby achieving stepless control of any opening degree from fully closed to fully open. Specifically, fully closed is 0% and fully open is 100%. This application allows setting multiple preset opening degrees between fully closed and fully open, such as 30% or 50%.

[0045] Each of the aforementioned adjusting cone mechanisms is used to receive the corresponding drive signal, and, based on the drive signal, adjust the position of the corresponding adjusting cone after adjusting the valve corresponding to the adjustable ejector.

[0046] The adjusting cone mechanism can continuously change the effective flow area of ​​the working fluid at the working fluid inlet of the adjustable ejector by changing the relative position of the adjusting cone in the nozzle or diffuser.

[0047] This application utilizes a monitoring module to monitor the pressure of the system fluid and the position of the regulating cone at multiple preset locations in real time, providing a real-time data foundation for the control module. The control module generates valve control signals based on the pressure deviation obtained from the real-time monitoring or according to the system operating mode, and combines this with the regulating cone position to generate drive signals. The sequential series connection of the multi-stage ejectors improves the system's response speed. Through the coordinated action of multiple valves and the regulating cone mechanism based on control and drive signals, the system can quickly stabilize and maintain anti-interference capabilities when dealing with working pressure fluctuations. It also achieves flow tracking and dynamic balance between each stage of the ejector when the flow rate of the natural gas to be recovered changes, significantly improving the system's operational efficiency. This application improves the system's regulation accuracy of the working fluid under varying operating conditions. Simultaneously, it comprehensively optimizes the system's overall performance in terms of response speed, operational stability, operating condition adaptability, energy efficiency, and safety.

[0048] In some embodiments, the multi-stage ejector 140 includes a first-stage ejector 1401, a second-stage ejector 1402, and a third-stage ejector 1403 connected in series; wherein the second-stage ejector and the third-stage ejector are the adjustable ejectors.

[0049] The plurality of valves 130 include a first-stage regulating valve 1301, a second-stage regulating valve 1302, a third-stage regulating valve 1303, a pressure relief ball valve 1304, a reinjection ball valve 1305, and a recovery ball valve 1306.

[0050] The recovery ball valve is installed on the inlet pipe of the ejected fluid of the first stage ejector;

[0051] The first-stage regulating valve, the second-stage regulating valve, and the third-stage regulating valve are respectively installed on the pipes at the working fluid inlets of the first-stage ejector, the second-stage ejector, and the third-stage ejector;

[0052] The outlet of the first-stage ejector is connected to the inlet of the ejected fluid of the second-stage ejector, and the outlet of the second-stage ejector is connected to the inlet of the ejected fluid of the third-stage ejector. The pressure relief ball valve and the reinjection ball valve are connected in parallel on the outlet pipe of the third-stage ejector.

[0053] Figure 2 A detailed structural diagram of the system provided in the embodiments of this application. Figure 2In this diagram, the first-stage primary fluid regulating valve represents the first-stage regulating valve, the second-stage primary fluid regulating valve represents the second-stage regulating valve, and the third-stage primary fluid regulating valve represents the third-stage regulating valve. The natural gas to be recovered represents the ejected fluid from the first-stage ejector, and the pressure relief ball valve is connected to the low-pressure discharge pipeline.

[0054] A corresponding regulating valve is installed at the working fluid inlet of each ejector stage, allowing the control module to independently and precisely control the pressurization power of each ejector stage. By adjusting the opening of each regulating valve, the flow rate and pressure of the working fluid input to each ejector stage can be set, thereby achieving pressure matching and flow distribution between each ejector stage. This stage-by-stage ejection structure overcomes interference between different ejectors in a multi-stage system, ensuring that the stage-by-stage pressurization process can be carried out efficiently and stably.

[0055] The reinjection ball valve corresponds to the normal operating path; the pressure relief ball valve corresponds to the safety protection path. The reinjection ball valve and the pressure relief ball valve are connected in parallel at the system outlet to physically separate the normal operating path and the safety protection path. In normal operating mode, the reinjection ball valve delivers the compliant mixed fluid; the pressure relief ball valve acts as a safety valve. This separation design ensures that in abnormal operating conditions such as overpressure or shutdown, the safety pressure relief function is not affected by the main process and is triggered quickly and reliably.

[0056] By employing a three-stage series ejector (first-stage, second-stage, and third-stage), the large overall pressure ratio can be rationally distributed to each ejector stage, ensuring that each ejector operates at a relatively reasonable compression ratio and thus guaranteeing the efficiency of the entire system. The second and third-stage ejectors are designed as adjustable ejectors because the system fluid pressure changes after the first-stage pressurization. The latter two ejector stages face more complex pressure fluctuation conditions, and the adjustable ejector structure provides a crucial adjustment mechanism for the system to cope with uncertain pressure fluctuations.

[0057] In some embodiments, the recovery ball valve is used to control the pressure of the ejected fluid entering the first-stage ejector;

[0058] The first-stage regulating valve, the second-stage regulating valve, and the third-stage regulating valve are respectively used to control the working fluid pressure entering the first-stage ejector, the second-stage ejector, and the third-stage ejector;

[0059] The pressure relief ball valve is used to relieve pressure and prevent backflow;

[0060] The reinjection ball valve is connected to a medium- and high-pressure pipeline and is used to reinject the injected fluid.

[0061] In some embodiments, the first-stage regulating valve, the second-stage regulating valve, and the third-stage regulating valve are respectively used to receive control signals based on the deviation between the target pressure and the actual pressure at the working fluid inlet of the first-stage ejector, the second-stage ejector, and the third-stage ejector, and adjust their respective openings based on the corresponding control signals to control the working fluid pressure input to the first-stage ejector, the second-stage ejector, and the third-stage ejector;

[0062] The recovery ball valve is used to receive a control signal based on the deviation between the target pressure and the actual pressure at the inlet of the first-stage ejector fluid, and adjust its own opening based on the corresponding control signal to control the pressure of the first-stage ejector fluid.

[0063] The pressure relief ball valve is used to receive a control signal based on the deviation between the target pressure and the actual pressure at the outlet of the third-stage ejector, and adjust its own opening based on the corresponding control signal to relieve pressure or prevent backflow.

[0064] The reinjection ball valve is used to receive the fully open control signal or the fully closed control signal output by the control module for open-loop control, so as to maintain the connection between the outlet of the third-stage ejector and the medium- and high-pressure pipeline.

[0065] The pressure relief ball valve is connected to a low-pressure pipeline. The outlet pressure of the pressure relief ball valve is atmospheric pressure, and it is used to relieve pressure and prevent backflow. The pressure relief ball valve is a safety valve, which opens when the system is abnormal.

[0066] The reinjection ball valve is connected to a medium- and high-pressure pipeline, and the outlet pressure of the ball valve is the design compression pressure, thereby enabling natural gas reinjection.

[0067] A recovery ball valve is installed at the inlet of the first-stage ejector, which is the intake port of the natural gas to be recovered, to control the pressure and flow rate of the natural gas to be recovered entering the system.

[0068] Figure 3 This is a module connection diagram of the system provided in an embodiment of this application. Figure 3 As shown, in order to achieve the connection between ejectors and between ejectors and valves, in Figure 3The volumetric module in the middle represents the pipeline, effectively avoiding iterative pressure calculations and making the model more realistic. Data transmitted between modules includes pressure p, temperature T, mass flow rate m, and regulating cone position x; solid lines represent fluid flow in the same direction as data transmission, while dashed lines represent fluid flow in the opposite direction. Pressure, temperature, and mass flow rate represent the locations of corresponding sensors installed at those points, such as temperature sensors monitoring temperature. The monitored values ​​of pressure, temperature, and mass flow rate are transmitted to the control system in real time as the basis for control. Temperature is used for compensation calculations; since gas density or speed of sound is significantly affected by temperature, combining pressure and temperature allows for the calculation of the system fluid density, thus converting volumetric flow rate into a more accurate mass flow rate. Mass flow rate is a key indicator for measuring system performance and efficiency. This is achieved by monitoring the ejector coefficient, system working fluid consumption, and implementing stable flow rate tracking control.

[0069] Figure 4 Performance diagram of the adjustable ejector of the system provided in the embodiments of this application. Figure 4 As shown, for adjustable ejectors under varying operating conditions, the predicted values ​​of the adjustable ejector can be compared intuitively with the simulated values ​​at several operating points. Taking the second-stage ejector as an example... Figure 4 In the graph, the horizontal axis represents the critical pressure, and the vertical axis represents the ejector coefficient. The blue line segment represents the performance prediction values ​​calculated by the ejector model for different working fluid pressures, and the red dots represent the simulation values ​​of the adjustable ejector under different working fluid pressures and adjusting cone positions. The intersection of the blue line segment and the red dot represent the same operating condition. The different working fluid pressures... They are 7.0×10 6 Pa, 8.0×10 6 Pa, 9.0 × 10 6 Pa and 10.0×10 6 Pa. The average relative errors between the ejector coefficient and the critical pressure at these working fluid pressure points are 3.36% and 2.43%, respectively, showing relatively small average relative errors. Furthermore, the performance variations of the ejector under different operating conditions calculated using this model are similar to those obtained through numerical simulation. Therefore, based on a modular approach, the ejector's steady-state equations, corrected using both machine learning and numerical simulation results, are used to model each structural component. The resulting dynamic model can be used for predictive analysis of ejector performance.

[0070] In some embodiments, the control module 120 includes a start / stop control unit 1201;

[0071] Before the system is started, the first-stage regulating valve, the second-stage regulating valve, the third-stage regulating valve, the pressure relief ball valve, the reinjection ball valve, and the recovery ball valve are all initially in the closed state.

[0072] The start / stop control unit 1201 is used to execute the first to third stages when the system's operating mode is switched to the start mode, and to control the opening of the first stage ejector, the second stage ejector and the third stage ejector in the order of pressurization.

[0073] The start / stop control unit 1201 is used to execute the fourth stage of starting the system after the fluid pressure at the outlet of the third-stage ejector reaches the pressure of the standard mixed fluid, by controlling the pressure relief ball valve to close and the reinjection ball valve to open.

[0074] The start / stop control unit 1201 is used to control the recovery ball valve to open during the fifth stage of starting the system in order to receive the ejected fluid;

[0075] The start / stop control unit 1201 is used to perform the reverse operation of the first stage to the fifth stage when the system's operating mode is switched to the stop mode. It sequentially controls the recovery ball valve to close, the reinjection ball valve to close while the pressure relief ball valve opens, the third-stage regulating valve to close, the second-stage regulating valve to close, and the first-stage regulating valve to close, so that the fluid pressure in the system is released step by step.

[0076] Figure 5 A flowchart illustrating the start-stop pressure control process of the system provided in this application embodiment. Figure 5 middle, The threshold value representing the pressure deviation or the pressure change rate deviation for each preset position; starting pressurization represents the start mode; stopping depressurization represents the stop mode.

[0077] Below, we will introduce the five stages of the startup mode in detail.

[0078] In the first stage, the first-stage regulating valve is opened. The monitoring module continuously monitors the pressure at the outlet of the first-stage ejector, which is the inlet pressure of the ejected fluid in the second-stage ejector. The system determines whether the pressure at this point has reached the preset target pressure and continuously adjusts the opening of the first-stage regulating valve until the pressure at the outlet of the first-stage ejector stabilizes within the set range.

[0079] In the second stage, after the pressure at the outlet of the first-stage ejector stabilizes, the second-stage regulating valve is opened. The monitoring module continuously monitors the outlet pressure of the second-stage ejector, which is also the inlet pressure of the ejected fluid in the third-stage ejector. The system waits and adjusts the regulating valve and the regulating cone of the second-stage ejector to gradually increase the outlet pressure of the second-stage ejector and stabilize it at its preset target value.

[0080] In the third stage, once the outlet pressure of the second-stage ejector stabilizes, the third-stage regulating valve is opened. The monitoring module then monitors the outlet pressure of the third-stage ejector and determines whether it meets the design requirements for reinjection pressure, i.e., the pressure of the compliant mixed fluid. When the outlet pressure of the third-stage ejector meets the requirements, it indicates that the mixed fluid can be reinjected into the medium- and high-pressure pipelines.

[0081] In the fourth stage, after the system outlet pressure reaches the target, first close the pressure relief ball valve connected to the low-pressure pipeline, and then open the reinjection ball valve leading to the medium- and high-pressure pipelines. This sequence of closing before opening ensures that high-pressure fluid in the pipeline is effectively prevented from flowing back into the system during the switching process between the pressure relief ball valve and the reinjection ball valve, thus ensuring the safety and reliability of the process switching.

[0082] In the fifth stage, after the system outlet switching is completed and the main flow is unobstructed, the system opens the recovery ball valve located on the inlet pipe of the first-stage ejector. The low-pressure ejected fluid to be recovered is introduced into the system and begins to undergo a stage-by-stage ejection and pressurization process. The system then switches to normal operating mode.

[0083] Below, we will introduce the five stages of the stop mode in detail.

[0084] In the first stage, the recovery ball valve is closed to cut off the supply of ejected fluid from the raw material gas source, so that the system stops receiving the gas to be processed, creating a safe premise for subsequent depressurization and shutdown operations.

[0085] In the second stage, the control module closes the reinjection ball valve to isolate the system from the high-pressure reinjection pipeline, preventing backflow of high-pressure fluid from the pipeline. Then, it opens the pressure relief ball valve to establish a pressure relief channel, ensuring that any subsequent pressure release can be safely diverted.

[0086] In the third stage, the regulating valves corresponding to the ejectors are closed one by one in the reverse order of the pressurization process. First, the third-stage regulating valve is closed, cutting off the final pressurization power source of the system, and the third-stage ejector stops working. The monitoring module monitors the outlet pressure of the third-stage ejector and confirms that the outlet pressure of the third-stage ejector begins to decrease steadily, meaning that the third-stage ejector has effectively stopped.

[0087] In the fourth stage, after confirming that the third-stage ejector has effectively stopped, the second-stage regulating valve is closed, the second-stage ejector stops working, and the system pressure is released back towards the inlet. This ensures the orderly release of system pressure between each ejector stage, preventing pressure buildup in intermediate stages.

[0088] In the fifth stage, the first-stage regulating valve is closed, cutting off the power to the front end. All pressurization units have stopped operating. The monitoring module continues to monitor until the pressure at each location has been safely released to atmospheric pressure or the predetermined safety value. At this point, the shutdown mode is complete.

[0089] Simulations of the system's start-up and shutdown modes revealed that in start-up mode, as the multi-stage ejectors gradually reach their operating pressure, the system's outlet pressure initially increases from atmospheric pressure (0.101 MPa) to 0.65 MPa at the outlet of the first-stage ejector, then to 2.1 MPa at the outlet of the second-stage ejector, and finally to 3.8 MPa at the outlet of the third-stage ejector. Only after all three stages of ejectors have started are the pressure relief ball valve and the reinjection ball valve switched, and the recovery ball valve opened, allowing the natural gas to be recovered to begin being ejected.

[0090] In some embodiments, the control module 120 includes an outer pressure control unit 1202 and an inner pressure control unit 1203, for adjusting the valve opening;

[0091] The outer pressure control unit 1202 is used to determine the corresponding pressure deviation based on each actual pressure and the corresponding target pressure;

[0092] The pressure inner loop control unit 1203 is used to determine the actual pressure change rate based on the actual pressure at the current moment and the actual pressure at the previous moment; to determine the pressure change rate deviation based on the preset pressure change rate and the actual pressure change rate; and to determine the control signal corresponding to the valve based on the pressure deviation and the pressure change rate deviation.

[0093] Figure 6 The control structure diagram of the system provided in the embodiments of this application is shown. Figure 6 The system includes eight control loops: the first control loop PID1, the second control loop PID2, the third control loop PID3, the fourth control loop PID4, the fifth control loop PID5, the sixth control loop PID6, the seventh control loop PID7, and the eighth control loop PID8.

[0094] Figure 6 The specific explanations of the corresponding parameters are shown in Table 1. Table 1 shows the actual parameters, target parameters, and control or drive signals of the control loop.

[0095] Table 1. Actual parameters, target parameters, and control or drive signals of the control loop.

[0096] ;

[0097] As shown in Table 1, since the reinjection ball valve's opening is directly controlled by the control module, it is not necessary to monitor the actual opening of the reinjection ball valve in real time. Actual parameters include the actual pressure of the working fluid in each stage of the ejector, the actual pressure of the first-stage ejected fluid, the actual position of each regulating cone, and the actual pressure of the mixed fluid. Target parameters include the target pressure of the working fluid in each stage of the ejector, the target pressure of the first-stage ejected fluid, the target position of each regulating cone, and the target pressure of the mixed fluid. Control or drive signals include the control signals for each valve, the drive signals for each regulating cone mechanism, and the control signals for the pressure relief ball valve, reinjection ball valve, and recovery ball valve.

[0098] This table details the configuration of eight control loops (PID1 to PID8) in the multi-stage ejector control system. Each control loop clearly defines its controlled variable and corresponding control output. Loops PID1 to PID3 are responsible for regulating the working fluid pressure of the first, second, and third stage ejectors, respectively, by adjusting the control signals of the corresponding regulating valves at each stage. Loop PID4 uses the mixed fluid pressure at the system outlet during pressure relief as the controlled variable, ensuring safe outlet pressure by adjusting the control signal of the pressure relief ball valve. Loop PID5 directly controls the opening of the reinjection ball valve, ensuring the precise execution of the reinjection process. Loop PID6 stabilizes the inlet pressure of the first-stage ejected fluid by adjusting the control signal of the recovery ball valve. Loops PID7 and PID8 are used for fine-tuning the internal structure of the ejectors, using the adjusting cone positions of the second and third stage ejectors, respectively, as controlled variables, optimizing ejector performance by changing the drive signals of the corresponding adjusting cone mechanisms. This configuration demonstrates how the control system achieves control over valve opening and adjusting cone positions through multi-loop collaboration.

[0099] In some embodiments, the control module 120 further includes a flow control unit 1204;

[0100] The flow control unit 1204 is configured to, when the pressure change rate deviation of the ejected fluid in the first-stage ejector exceeds a preset pressure change rate deviation, and simultaneously the pressure change rate deviation of the working fluid in any of the multi-stage ejectors exceeds a preset pressure change rate deviation, firstly adjust the opening of the regulating valve and the position of the regulating cone corresponding to any ejector in sequence to prioritize stabilizing the pressure of the working fluid; then, by adjusting the opening of the recovery ball valve and continuously adjusting the position of the regulating cone of the adjustable ejector, control the flow rate of the ejected fluid.

[0101] Figure 7 A flowchart illustrating the flow tracking control process of the system provided in this application embodiment. Figure 7As shown, in the face of two types of variable operating conditions, namely the change in compressor unit speed and the pressure fluctuation of high-pressure natural gas pipeline, the system adopts a differentiated regulation strategy to achieve stable tracking control of the system fluid flow.

[0102] When changes in compressor unit speed cause the vented natural gas flow rate to fluctuate within 50% to 100% of its maximum value, the system primarily adjusts the regulating cone of the two-stage adjustable ejector and the recovery ball valve. Specifically, by adjusting the opening of the recovery ball valve, the pressure of the ejected fluid is stabilized at a set value, while simultaneously driving the regulating cone mechanism to precisely move the regulating cone to a set position adapted to this flow rate change.

[0103] When the pressure in a high-pressure natural gas pipeline fluctuates significantly within the range of 7 to 10 MPa, the system primarily adjusts the regulating cones of the two-stage adjustable ejector and the corresponding working fluid regulating valves. After stabilizing the working fluid pressure by adjusting the valves, the regulating cone mechanism is then driven to adjust it to a preset position to cope with the pressure fluctuations.

[0104] The key difference between the two adjustment strategies mentioned above lies in the control mode of the regulating cone: coarse adjustment with discrete position is used to deal with pressure fluctuations, while fine adjustment with continuous position is used to deal with flow rate changes.

[0105] Throughout the flow control process, when high-pressure pipeline pressure fluctuations and vented natural gas flow changes occur simultaneously, the high-pressure pipeline pressure fluctuation condition is addressed first, followed by the vented natural gas flow change condition. This hierarchical control strategy, which first stabilizes the main parameters through coarse adjustments and then optimizes the flow rate through fine adjustments, effectively ensures the system's control stability and adaptability under complex and variable operating conditions.

[0106] In some embodiments, the control module 120 further includes an input pressure limit control unit 1205 and an output pressure limit control unit 1206;

[0107] The input pressure limit control unit 1205 is used to output an interrupt signal to each of the regulating valves and close each of the regulating valves when any of the actual pressures exceeds the preset limit pressure, so as to cut off the input of the working fluid to each of the multi-stage ejectors.

[0108] The output pressure limit control unit 1206 is used to output a pressure relief control signal to the pressure relief ball valve when the mixed fluid pressure at the system outlet is greater than the preset pressure relief pressure; the pressure relief control signal is used to control the pressure relief ball valve to open to the preset pressure relief opening degree.

[0109] Figure 8 The pressure limiting flowchart of the system provided in the embodiments of this application is as follows: Figure 8 As shown,

[0110] The system's pressure safety protection mechanism is implemented through the input pressure limit control unit and the output pressure limit control unit.

[0111] The input pressure limit control unit is responsible for protecting the working fluid from pressure over-limits. The monitoring module continuously monitors the actual pressure at the working fluid inlet of the first-stage ejector, second-stage ejector, and third-stage ejector. If the actual pressure at all monitoring points does not exceed the preset limit pressure, the control module outputs a hold signal to each regulating valve to maintain the current state and continue monitoring; if the actual pressure at any monitoring point exceeds the limit pressure, the control module sends an interrupt signal to the corresponding regulating valve, closing all regulating valves to quickly cut off the supply of working fluid and achieve protection against upstream pressure over-limits.

[0112] The output pressure limit control unit is responsible for over-limit protection of the outlet pressure. The monitoring module continuously monitors the pressure of the mixed fluid at the outlet of the third-stage ejector. If the pressure of the mixed fluid does not exceed the preset relief pressure, the control module instructs the relief ball valve to remain fully closed; if the outlet pressure exceeds the relief pressure, the control module sends a control signal to the relief ball valve, controlling it to open to the preset relief opening degree to relieve pressure, thereby preventing ejector backflow or equipment damage due to excessive outlet pressure. The set value of the relief pressure should be lower than the ejector backflow pressure to allow for a margin to prevent backflow.

[0113] Figure 9 This is a schematic diagram illustrating the impact of flow tracking control on system performance during pipeline pressure fluctuations, provided in an embodiment of this application. Figure 9 As shown, the horizontal axis represents the working fluid inlet pressure of the second-stage and third-stage ejectors, in megapascals (MPa), ranging from 7 to 10 MPa; the left vertical axis represents the mass flow rate of the ejected fluid in the first-stage ejector, in kilograms per second (kg / s); and the right vertical axis represents the total mass flow rate of the working fluid in the system. Figure 9 In this context, the mass flow rate of the natural gas to be recovered represents the mass flow rate of the ejected fluid in the first-stage ejector, the total flow rate required without control represents the total mass flow rate required by the first-stage ejector, and the total flow rate required with control represents the total mass flow rate required by the second-stage and third-stage ejectors.

[0114] Since pipeline pressure fluctuations primarily affect the second and third stage ejectors, while the recoverable mass flow rate of low-pressure natural gas is mainly related to the first stage ejector, it remains essentially constant at approximately 0.003 kg / s under fixed operating conditions. If the second and third stage ejectors are also fixed and uncontrolled, the total primary flow rate of high-pressure natural gas consumed by the entire system will increase with rising pipeline pressure. As the pipeline pressure increases from 7.0 MPa to 10 MPa, the primary flow rate consumption will increase from 0% to 42%. However, when the second and third stage ejectors are adjustable and controlled, dynamically adjusting to follow pipeline pressure fluctuations, the total primary flow rate consumed by the entire system can remain nearly constant with rising pipeline pressure, requiring no additional primary flow rate consumption and maintaining the system's flow rate at its fixed design conditions. Furthermore, the increase in pipeline pressure can potentially increase the compression capacity of the entire system, providing a wider margin to prevent backflow.

[0115] Figure 10 This diagram illustrates the impact of flow tracking control on system performance when the flow rate of the natural gas to be recovered changes, as provided in the embodiments of this application. Figure 10 As shown, the horizontal axis represents the actual pressure of the ejected fluid in the first-stage ejector, the left vertical axis represents the mass flow rate of the ejected fluid in the first-stage ejector, and the right vertical axis represents the total mass flow rate of the working fluid in the system.

[0116] Since changes in the flow rate of the natural gas to be recovered primarily affect the first-stage ejector, as the flow rate decreases, the upstream pressure of the recovery ball valve also decreases. Consequently, the pressure and flow rate of the ejected fluid in the first-stage ejector decrease simultaneously, specifically from approximately 0.003 kg / s to approximately 0.0015 kg / s. Taking 0.003 kg / s as the maximum value, this represents a decrease from 100% to 50% of the maximum value. If the second and third-stage ejectors are also fixed and without control, the total primary flow rate of the high-pressure natural gas consumed by the entire system will not change due to the change in the flow rate of the natural gas to be recovered, but will remain at the same value, reducing the system's operating performance. However, when the second and third-stage ejectors are adjustable and controlled, achieving dynamic adjustment in response to changes in the flow rate of the natural gas to be recovered, the primary flow rate consumed by the entire system decreases as the flow rate of the natural gas to be recovered decreases. There is no decrease when the recovery flow rate is at its maximum, and the primary flow rate decreases by no more than 22% when the recovery flow rate is half, effectively improving the system's operating performance.

[0117] The beneficial effects of this application include the following: 1) Simulations of the start-up and shutdown process show that, compared with conventional control, cascade control has a faster response speed. When the pressure signal changes from a ramp to a stable state, cascade control can reach a steady state more quickly. 2) In the control loop of the pressure relief ball valve at the system outlet, cascade control can better prevent backflow and ensure safety compared with conventional control. 3) Simulations of variable operating conditions show that, under pipeline pressure fluctuations, these mass flow rates exhibit slight fluctuations during the switching of the main pressure values, but quickly stabilize and remain essentially unchanged after the switching is completed. 4) During the change of the flow rate of the natural gas to be recovered, the flow-following control can balance the flow between the ejectors, and the entire system can quickly and stably reach the target flow rate. When the second and third stage ejectors use adjustable ejectors with control to achieve dynamic adjustment following the change of the flow rate of the natural gas to be recovered, the primary flow rate consumed by the entire system decreases as the flow rate of the natural gas to be recovered decreases. There is no decrease when the recovery flow rate is at its maximum, and the primary flow rate decreases by no more than 22% when the recovery flow rate is half, effectively improving the system's operating performance.

[0118] It should be noted that the descriptions of the above device embodiments are similar to those of the above method embodiments, and have similar beneficial effects. For technical details not disclosed in the system embodiments of this application, please refer to the descriptions of the method embodiments of this application for understanding.

[0119] It should be understood that the phrase "one embodiment" or "an embodiment" throughout the specification means that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of this application. Therefore, "in one embodiment" or "in an embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. It should be understood that in the various embodiments of this application, the sequence numbers of the above-described processes do not imply a sequential order of execution; the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application. The sequence numbers of the above-described embodiments are merely descriptive and do not represent the superiority or inferiority of the embodiments.

[0120] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0121] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods, such as: multiple units or components can be combined, or integrated into another system, or some features can be ignored or not executed. In addition, the coupling, direct coupling, or communication connection between the various components shown or discussed can be through some interfaces, and the indirect coupling or communication connection between devices or units can be electrical, mechanical, or other forms.

[0122] The units described above as separate components may or may not be physically separate, and the components shown as units may or may not be physical units; they may be located in one place or distributed across multiple network units; some or all of the units may be selected to achieve the purpose of the embodiments of this application according to actual needs. In addition, each functional unit in the embodiments of this application may be fully integrated into one processing unit, or each unit may be a separate unit, or two or more units may be integrated into one unit; the integrated unit may be implemented in hardware or in the form of hardware plus software functional units.

[0123] Alternatively, if the integrated units described above are implemented as software functional modules and sold or used as independent products, they can also be stored in a computer-readable storage medium. Based on this understanding, the technical solutions of the embodiments of this application, or the parts that contribute to related technologies, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause the device automatic test line to execute all or part of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as mobile storage devices, ROMs, magnetic disks, or optical disks.

[0124] The methods disclosed in the several method embodiments provided in this application can be arbitrarily combined to obtain new method embodiments without conflict. The features disclosed in the several method or device embodiments provided in this application can be arbitrarily combined to obtain new method embodiments or device embodiments without conflict.

[0125] The above description is merely an embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A step-by-step control system for a super-high compression ratio multi-stage ejector, the system comprising a monitoring module, a control module, a plurality of valves, and a multi-stage ejector; characterized in that, The multiple-stage ejectors are connected in series, and the outlet of a former-stage ejector is connected with the injected fluid inlet of a latter-stage ejector to realize step-by-step pressure boosting; the multiple-stage ejectors comprise a fixed first-stage ejector and adjustable ejectors provided with adjusting cone mechanisms, the injected fluid inlet of the first-stage ejector is used to receive the injected fluid, the working fluid inlets of each stage of the ejectors are used to receive working fluid, and the outlet of the last-stage ejector is used to output the qualified mixed fluid to realize the reinjection of the injected fluid in the qualified mixed fluid; The system comprises: The monitoring module is used to monitor pressure and position parameters; the pressure and position parameters comprise actual pressures of system fluid passing through multiple preset positions of the system and actual adjusting cone positions corresponding to each adjustable ejector; and the monitoring module is used to send the monitored pressure and position parameters to the control module; the system fluid comprises any one of the working fluid, the injected fluid and the mixed fluid; The control module is used to determine target pressures of system fluid passing through each preset position; The control module is also used to receive each pressure and position parameter; generate a control signal corresponding to the valve based on a pressure deviation of each actual pressure from a corresponding target pressure or based on an operation mode of the system; and generate a driving signal corresponding to the adjusting cone mechanism based on the actual pressure of each adjustable ejector and the actual position of the adjusting cone corresponding to the adjustable ejector; send each control signal to the corresponding valve; and send each driving signal to the corresponding adjusting cone mechanism; Each valve is used to receive the corresponding control signal and adjust the opening degree of the corresponding valve based on each control signal; Each adjusting cone mechanism is used to receive the corresponding driving signal and adjust the position of the corresponding adjusting cone based on the driving signal after adjusting the valve corresponding to the adjustable ejector.

2. The system of claim 1, wherein, The multiple-stage ejectors comprise a first-stage ejector, a second-stage ejector and a third-stage ejector connected in series; the second-stage ejector and the third-stage ejector are adjustable ejectors; the multiple valves comprise a first-stage adjusting valve, a second-stage adjusting valve, a third-stage adjusting valve, a pressure relief ball valve, a reinjection ball valve and a recovery ball valve; The recovery ball valve is arranged on the injected fluid inlet pipeline of the first-stage ejector; The first-stage adjusting valve, the second-stage adjusting valve and the third-stage adjusting valve are respectively arranged on the pipelines of the working fluid inlets of the first-stage ejector, the second-stage ejector and the third-stage ejector; The outlet of the first-stage ejector is connected with the injected fluid inlet of the second-stage ejector, the outlet of the second-stage ejector is connected with the injected fluid inlet of the third-stage ejector, and the pressure relief ball valve and the reinjection ball valve are arranged in parallel on the outlet pipeline of the third-stage ejector.

3. The system of claim 2, wherein, The recovery ball valve is used to control the pressure of the injected fluid entering the first-stage ejector. The first-stage regulating valve, the second-stage regulating valve and the third-stage regulating valve are respectively used for controlling the working fluid pressure entering the first-stage ejector, the second-stage ejector and the third-stage ejector; The pressure relief ball valve is used for pressure relief and backflow prevention; The reinjection ball valve is connected with the medium-high pressure pipeline and is used for realizing reinjection of the injected fluid.

4. The system of claim 3, wherein, The first-stage regulating valve, the second-stage regulating valve and the third-stage regulating valve are respectively used for receiving a control signal based on a deviation between a target pressure and an actual pressure at a working fluid inlet of the first-stage ejector, the second-stage ejector and the third-stage ejector, and adjusting an opening degree of each valve based on the corresponding control signal, so as to control the working fluid pressure entering the first-stage ejector, the second-stage ejector and the third-stage ejector; The recovery ball valve is used for receiving a control signal based on a deviation between a target pressure and an actual pressure at a working fluid inlet of the first-stage ejector, and adjusting an opening degree of the recovery ball valve based on the corresponding control signal, so as to control the working fluid pressure of the first-stage ejector; The pressure relief ball valve is used for receiving a control signal based on a deviation between a target pressure and an actual pressure at an outlet of the third-stage ejector, and adjusting an opening degree of the pressure relief ball valve based on the corresponding control signal, so as to realize pressure relief or backflow prevention; The reinjection ball valve is used for receiving an open control signal or a close control signal output by the control module to realize open-loop control, so as to maintain the connection between the third-stage ejector outlet and the medium-high pressure pipeline.

5. The system of claim 2, wherein, The control module comprises a start-stop control unit; Before starting the system, initial states of the first-stage regulating valve, the second-stage regulating valve, the third-stage regulating valve, the pressure relief ball valve, the reinjection ball valve and the recovery ball valve are all closed states; The start-stop control unit is used for executing a first stage to a third stage to control the first-stage ejector, the second-stage ejector and the third-stage ejector to be opened in a pressurization sequence when an operation mode of the system is switched to a start mode; The start-stop control unit is used for executing a fourth stage to control the pressure relief ball valve to be closed and the reinjection ball valve to be opened when a fluid pressure at the third-stage ejector outlet reaches a pressure of the qualified mixed fluid, so as to start the system; The start-stop control unit is used for executing a fifth stage to control the recovery ball valve to be opened to receive the injected fluid when starting the system; The start-stop control unit is used for executing reverse operations of the first stage to the fifth stage to control the recovery ball valve to be closed, the reinjection ball valve to be closed and the pressure relief ball valve to be opened at the same time, the third-stage regulating valve to be closed, the second-stage regulating valve to be closed and the first-stage regulating valve to be closed in sequence when the operation mode of the system is switched to a stop mode, so as to make the fluid pressure in the system be gradually released.

6. The system of claim 1, wherein, The control module comprises a pressure outer loop control unit and a pressure inner loop control unit, and is used for adjusting the valve opening degree; The pressure outer loop control unit is used for determining the pressure deviation based on each actual pressure and the corresponding target pressure. The pressure inner ring control unit is configured to determine an actual pressure change rate based on an actual pressure at a current time and an actual pressure at a previous time; and determine a pressure change rate deviation based on a preset pressure change rate and the actual pressure change rate. The control signal corresponding to the valve is determined based on the pressure deviation and the pressure change rate deviation.

7. The system of claim 6, wherein, The control module further comprises a flow control unit. The flow control unit is configured to, when the pressure change rate deviation of the induced fluid of the first-stage ejector exceeds a preset pressure change rate deviation, and when the pressure change rate deviation of the working fluid of any of the multi-stage ejectors exceeds a preset pressure change rate deviation, first adjust the opening degree of the valve corresponding to any of the ejectors and the adjusting cone position in sequence to stabilize the pressure of the working fluid preferentially; and then adjust the opening degree of the recovery ball valve and continuously adjust the adjusting cone position of the adjustable ejector to control the flow of the induced fluid.

8. The system of claim 2, wherein, The control module further comprises an input pressure limit control unit and an output pressure limit control unit. The input pressure limit control unit is configured to output an interrupt signal to each of the valves to close each of the valves to cut off the input of the working fluid to each of the multi-stage ejectors when any of the actual pressures is greater than a preset limit pressure. The output pressure limit control unit is configured to output a pressure relief control signal to the pressure relief ball valve when the pressure of the mixed fluid at the outlet of the system is greater than a preset pressure relief pressure; and the pressure relief control signal is configured to control the pressure relief ball valve to open to a preset pressure relief opening degree.

Images