MVR steam compressor

Abstract

The invention belongs to the technical field of compressors, and particularly relates to an MVR (mechanical vapor recompression) vapor compressor, a detection control system with multi-stage recognition capability is introduced on the basis of compressor basic equipment, and the system collects vapor parameters, mechanical states and process state data in real time through a multi-dimensional state sensing module; the operation stage identification module intelligently divides the system operation process into an initial starting stage, a transition stage and a stable operation stage according to the data; and the self-adaptive control module calls a corresponding preset strategy set according to the identified different stages and dynamically adjusts the rotating speed and the compression ratio of the compressor, for example, low-speed soft start is executed in the initial stage of start, smooth tracking adjustment is performed in the transition period, and accurate and stable control is implemented in the stable operation period. Self-adaptive and refined regulation and control of the whole process from starting to stabilization of the system are achieved, mechanical and electrical impact is effectively reduced, variable working condition adaptability and operation stability are improved, and the overall energy efficiency is optimized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of compressors, in particular to an MVR steam compressor. BACKGROUND

[0002] The MVR steam compressor is a core device in evaporation, concentration, crystallization and other processes. It compresses and heats the secondary steam through the compressor, so that it regains the heating capacity, thereby realizing heat energy recycling and greatly reducing system energy consumption. In the prior art (such as Chinese patents CN120926068A and CN120759750A), the control of the MVR steam compressor is mostly focused on maintaining parameters in stable working conditions, for example, by detecting steam temperature, pressure and motor current and other parameters, the compressor speed or inlet guide vane is adjusted to maintain the stability of the outlet steam parameters.

[0003] However, in the MVR system, similar adaptive control ideas have not been fully applied, especially in dealing with dynamic processes such as system startup, load mutation and process changes, the existing control system often shows lag or roughness, which can easily cause the following problems: Large impact during startup: when the system is cold started, the steam parameters are low, and if it is directly operated at rated speed or high compression ratio, the compressor efficiency is low, and the motor load increases sharply, which can easily cause electrical and mechanical impact and affect the service life of the equipment; Poor adaptability to variable conditions: when the feed concentration, flow or evaporation load changes, the steam generation changes, and the traditional control method responds slowly, which can cause compressor surge, motor overload or steam parameter fluctuations, affecting the process stability; Energy efficiency is not optimal: during the entire running cycle, especially during the transition from startup to stable, the control system cannot fine-tune according to real-time conditions, resulting in higher energy consumption in some periods, and there is still room for improvement in overall energy efficiency.

[0004] Therefore, there is an urgent need for an MVR steam compressor system that can sense the system running stage and adaptively adjust the control strategy according to the characteristics of different stages to achieve the goals of smooth startup, efficient operation and safe adaptation to variable conditions. SUMMARY

[0005] Based on the technical problems existing in the prior art, the present application provides an MVR steam compressor.

[0006] The MVR steam compressor provided by the present application comprises an evaporation unit, a compression unit, a heat exchange unit, a connecting pipeline and a detection control system, the compression unit comprises a compressor and a driving motor thereof, and the detection control system comprises: A multi-dimensional state sensing module for real-time acquisition of system running state data; A running phase identification module, a signal input end of which is electrically connected with the multi-dimension state sensing module, for identifying a running phase of the current system according to the data, the running phase at least including a start-up initial stage, a transition stage and a stable running stage; An adaptive control module, a signal input end of which is electrically connected with the running phase identification module, and a control output end of which is electrically connected with at least one of the driving motor and the intake adjusting device of the compressor; the adaptive control module pre-storing a control strategy set corresponding to different running phases, and calling a corresponding strategy to dynamically adjust at least one of the rotating speed and the compression ratio of the compressor according to the identified running phase.

[0007] Preferably, the multi-dimension state sensing module includes: A steam parameter sensor, at least including an inlet steam temperature sensor and an inlet steam pressure sensor installed on the steam inlet side of the compressor, and an outlet steam temperature sensor and an outlet steam pressure sensor installed on the steam outlet side of the compressor; A mechanical state sensor, at least including a vibration sensor and a current sensor installed on the driving motor.

[0008] Preferably, the multi-dimension state sensing module further includes a process state sensor, the process state sensor being a liquid level meter installed on the evaporation unit, or being a running time signal generated inside the detection control system.

[0009] Preferably, the identification logic of the running phase identification module is: The determination condition of the start-up initial stage is that at least one of the following conditions is met since the system starts up: the inlet steam temperature is lower than a first temperature threshold, the inlet steam pressure is lower than a first pressure threshold, and the running time is less than a first time threshold; The determination condition of the stable running stage is that the inlet steam temperature and the inlet steam pressure are continuously stable in their respective target intervals for more than a second time threshold, and the current and the vibration value of the driving motor are in a normal range; The transition stage is a stage that does not meet the determination condition of the start-up initial stage and does not reach the determination condition of the stable running stage.

[0010] Preferably, the control strategy pre-stored in the adaptive control module for the start-up initial stage includes: controlling the driving motor to start up at an initial rotating speed lower than a rated rotating speed, and limiting a rotating speed climbing rate thereof; and simultaneously controlling the intake adjusting device to maintain a small opening degree.

[0011] Preferably, the pre-stored control strategy in the adaptive control module for the transition period comprises: adopting closed-loop feedback control based on the deviation of the inlet steam parameters from the target values, and combining feed-forward compensation based on the change rate of the inlet steam parameters, to jointly adjust the rotating speed of the driving motor; and the opening of the air intake adjusting device and the rotating speed adjustment are cooperatively operated.

[0012] Preferably, in the transition period control strategy, the control parameters of the closed-loop feedback control can be dynamically adjusted according to the duration of the transition period or the closeness of the current steam parameters to the target values.

[0013] Preferably, the pre-stored control strategy in the adaptive control module for the stable operation period comprises: precise feedback control with at least one of maintaining the temperature and pressure of the compressor outlet steam stable at a set value as the main target; and continuously monitoring the change trend of the inlet steam pressure for preventive adjustment.

[0014] Preferably, the air intake adjusting device is an adjusting valve installed on the compressor outlet pipeline, or is an inlet adjustable guide vane mechanism of the compressor, or is a linkage combination of the two.

[0015] Compared with the prior art, the present application provides an MVR steam compressor, which has the following beneficial effects: 1. By identifying the initial start-up period and applying a gentle start-up strategy, the overload and stress impact of the driving motor and the mechanical parts of the compressor under cold-state and low-parameter working conditions are effectively avoided, and the service life of the equipment is prolonged.

[0016] 2. By distinguishing the transition period and the stable operation period, and adopting a specially optimized smooth transition strategy for the transition period, the system can reach a new stable point more quickly and stably when the load changes or the process is adjusted, the fluctuation amplitude and duration of the steam parameters are reduced, and the process stability is improved.

[0017] 3. Different control targets and parameters are adopted for different operating stages, which avoids energy waste in the start-up stage and the variable working condition stage, makes the system operate close to the optimal efficiency point in a wider working condition range, and improves the overall energy efficiency.

[0018] 4. Through multi-dimensional state perception and stage recognition, the system can identify abnormal working conditions (such as difficult start-up and prolonged transition abnormalities) earlier, and can trigger more targeted alarm or protection actions, thereby improving the reliability and safety of the system. BRIEF DESCRIPTION OF DRAWINGS

[0019] Fig. 1 Figure 1 is a first angle structural schematic view of an MVR steam compressor according to the present application; Fig. 2A second angle structure schematic diagram of the MVR steam compressor is provided for the present application. Fig. 3 A principle block diagram of the detection control system of the present application is provided. Fig. 4 A flow chart of the running stage identification and strategy switching in the system workflow of the present application is provided.

[0020] In the figure: 1, base; 2, evaporator; 3, compressor; 4, heat exchanger; 5, first pipeline; 6, second pipeline; 7, connecting pipe; 8, machine base; 9, support frame; 10, driving motor; 11, regulating valve. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments of the present application.

[0022] In the description of the present application, it should be understood that the terms “up”, “down”, “front”, “back”, “left”, “right”, “top”, “bottom”, “inner”, “outer” and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0023] Referring to Figs. 1 to 4 The present application provides a MVR steam compressor.

[0024] I. Mechanical structure of the equipment The MVR steam compressor mainly comprises an evaporation unit, a compression unit, a heat exchange unit, a connecting pipeline and a support structure, and all the units are integrated on a stable base 1.

[0025] The evaporation unit: the core is an evaporator 2, which is fixedly installed on the left side or front part of the base 1 (according to the layout), and the evaporator 2 is used to receive the material to be concentrated, evaporate the water in the material by using the heat recovered by the system, and generate low-temperature and low-pressure secondary steam. A liquid level meter is installed on the evaporator 2, which is used to monitor the liquid level of the material, and the signal can be used as an indirect reference for evaluating the stability of steam generation.

[0026] Compression Unit: The core is the compressor 3 and its drive motor 10. In this embodiment, the compressor 3 is preferably a multi-stage centrifugal steam compressor with a wide operating condition adjustment range. The compressor 3 is fixedly mounted in the middle of the base 1 via a sturdy base 8. The drive motor 10 is coaxially connected to the compressor 3, providing it with power. A vibration sensor can be installed on the non-drive end of the drive motor 10, and a current sensor can be installed on the power line.

[0027] Heat exchange unit: The core is the heat exchanger 4, which is securely mounted on the right side or rear of the base 1 via a support frame 9. The heat exchanger 4 is usually a shell-and-tube type or a plate type, used to realize the heat exchange between high-temperature and high-pressure steam and the material to be heated (or the circulating material in the system).

[0028] Connecting pipes: First pipe 5: Connects the steam outlet of evaporator 2 to the steam inlet of compressor 3, used to deliver low-temperature, low-pressure secondary steam to compressor 3. An inlet steam temperature sensor and an inlet steam pressure sensor are installed on first pipe 5 near the inlet of compressor 3.

[0029] Second pipe 6 connects the steam outlet of compressor 3 to the steam inlet of heat exchanger 4, and is used to transport compressed high-temperature and high-pressure steam to heat exchanger 4. A regulating valve 11 is installed on second pipe 6 (which, along with the adjustable inlet guide vane mechanism of compressor 3, can function independently as an intake regulating device, or the two can be linked), used to regulate steam flow and system pressure. An outlet steam temperature sensor and an outlet steam pressure sensor are installed on second pipe 6 near the inlet of heat exchanger 4.

[0030] Connecting pipe 7: Connects the condensate outlet (or secondary side) of heat exchanger 4 to other parts of the equipment (such as the preheater, the heating chamber of evaporator 2) to complete the recovery of condensate or further utilization of heat.

[0031] Support structure: Base 1 provides a rigid foundation for the entire system; base 8 is used for precise alignment and fixing of compressor 3; support frame 9 is used to support heat exchanger 4, and its height and angle design must ensure smooth pipeline connection and no stress concentration.

[0032] II. Composition of the Detection and Control System The core of this equipment's intelligence lies in its detection and control system, which consists of a sensor network (multi-dimensional state sensing modules) and a controller.

[0033] Sensor installation method: Steam parameter sensor: Inlet steam temperature sensor (e.g., Pt100 RTD): A threaded tube socket is used, inserted vertically or at an angle into the wall of the first pipe 5. The sensing element extends into the central flow field region of the pipe, ensuring that the mainstream steam temperature is measured. The installation position is approximately 3-5 times the pipe diameter from the compressor 3 inlet to avoid the influence of local disturbances.

[0034] Inlet steam pressure sensor (such as a piezoresistive pressure transmitter): A pressure tapping short tube is welded to the top or side of the first pipe 5, with the tapping port perpendicular to the flow direction to avoid erosion. The pressure tapping tube is connected to the sensor using a capillary tube or a direct thread, and proper insulation is provided to prevent condensation from causing measurement errors.

[0035] The outlet steam temperature sensor and outlet steam pressure sensor are installed on the second pipe 6. Their installation method is similar to that of the inlet sensor, but protection against higher temperatures and pressures is required. Generally, higher-grade temperature and pressure sensors are selected. The installation position is after the regulating valve 11 and before the heat exchanger 4 to reflect the final state of the steam entering the heat exchanger.

[0036] Mechanical condition sensors: Vibration sensors (such as accelerometers): These are mounted on the horizontal and vertical directions of the bearing housing at the non-drive end of the drive motor 10, using a magnetic base or bolts for fixing, and are used to monitor the intensity of mechanical vibration during the operation of the drive motor 10.

[0037] Current sensor (such as Hall effect current transformer): It is connected to a phase conductor of the main power supply of drive motor 10 and is used to monitor the load current of drive motor 10 in real time.

[0038] Process status sensors: Level gauge (such as radar level gauge): Installed on the top of evaporator 2, it continuously measures the material level. The stability or trend of the level can indirectly reflect the stability of steam generation.

[0039] In addition, logic and time signals such as system startup commands and running time are generated and recorded by the controller's internal program, forming a virtual process state perception.

[0040] Controller and its logic (operational phase identification module and adaptive control module): The controller can be a high-performance industrial PLC (programmable logic controller) or DCS (distributed control system) controller. Its input module is connected to all the sensor signals mentioned above, and its output module is connected to the frequency converter of the drive motor 10 (for speed regulation) and the actuator of the regulating valve 11 (for opening adjustment).

[0041] The operation phase identification module is built into the controller as a software algorithm. Its identification logic is as follows (the specific threshold needs to be set according to the equipment model and process; this is just an example): a. Initial Startup Judgment: Upon receiving the system start command, the controller immediately enters the "Initial Startup" stage. It continuously monitors the inlet steam temperature T_in and pressure P_in. If T_in < 85°C and P_in < 20 kPa (absolute pressure), or the start-up time < 120 seconds, the "Initial Startup" judgment is maintained. If any condition is not met, the system prepares to proceed to the next stage judgment.

[0042] b. Stable Operation Period Determination: After the system is no longer in the "initial startup" stage, the stability conditions are determined. The target inlet temperature T_target is set to 95°C, and the target pressure P_target is set to 30 kPa, with allowable deviations of ±2°C and ±1 kPa, respectively. If, for 300 consecutive seconds, T_in and P_in continuously fall within the target range, and the drive motor current I_motor fluctuates by less than 5% between 80% and 100% of its rated value, with a vibration value below 4.5 mm / s, then the system is determined to have entered the "stable operation period."

[0043] c. Transition Period Determination: From the end of the "Initial Start-up" conditions until the "Stable Operation Period" conditions are met, the system is in a "transition period." Furthermore, during the "Stable Operation Period," if the inlet steam parameters are detected to deviate continuously from the target value by a certain range due to load changes (e.g., T_in changes by more than ±5°C or P_in changes by more than ±3 kPa), and this deviation lasts for more than 30 seconds, the system is determined to have entered a "transition period" caused by load changes, until the stable operation conditions are met again.

[0044] The adaptive control module is also built into the controller in the form of a control algorithm. It calls different control subroutines based on the current stage flag output by the operation stage identification module. a. Initial control strategy: Speed ​​control: The drive motor 10 is given a low initial speed n_start, for example, 30% of the rated speed (achieved through the frequency converter), and then the speed command is gradually increased at a slow slope (e.g., 5% of the rated speed per minute). Rapid steam heating is not pursued in this stage.

[0045] Pressure / flow control: Keep the regulating valve 11 at a small opening (e.g., 30%) to limit the steam flow into the compressor 3, thereby maintaining a low compression ratio and reducing the load.

[0046] Objective: To allow compressor 3 and drive motor 10 to "warm up" under low load, while waiting for the steam parameters generated by evaporator 2 to rise naturally and slowly.

[0047] b. Transition period control strategies: Speed ​​feedforward-feedback composite control: The controller performs PID calculations based on the difference (e_T) between the real-time inlet steam temperature T_in and its target value T_target, outputting a reference speed adjustment. Simultaneously, feedforward compensation is introduced: based on the rate of increase of T_in (dT_in / dt), an additional speed increment proportional to this rate is added to respond in advance to the increase in steam energy, making the speed increase curve more closely match the steam generation curve, achieving smooth catching-up.

[0048] Valve coordinated control: The opening of regulating valve 11 is coordinated with the increase in rotational speed. Initially, as the rotational speed increases, the valve is gradually opened wider (for example, the valve opening increases by 2% for every 5% increase in rotational speed) to gradually improve the system's processing capacity and compression ratio. When the steam parameters approach the target value, the valve control gradually transitions from open-loop coordination to closed-loop PID control with the goal of stabilizing the outlet pressure P_out.

[0049] Parameter Adaptation: In this stage, the parameters of the PID controller (such as the proportional gain Kp) can be set to dynamically adjust as the duration of the "transition period" or the current steam parameters approach the target value. For example, a smaller Kp is used in the early stages of the transition to avoid overshoot; a larger Kp is used when approaching stability to improve regulation accuracy.

[0050] c. Control strategies during stable operation: Precise feedback control: The primary control objective is to maintain the outlet steam temperature T_out and / or pressure P_out stable at the process setpoint. An independent, parameter-tuned PID controller is used to finely adjust the speed of the drive motor 10 (fine-tuning) and / or the opening of the regulating valve 11 based on the deviation between the measured values ​​of T_out / P_out and the setpoint.

[0051] Pre-regulation for minor load changes: Continuously monitor the trend of inlet steam pressure P_in. If a slow upward trend of P_in is detected (indicating a possible slight increase in evaporation load), the controller can slightly increase the speed setpoint before the outlet parameters change significantly, thus proactively suppressing disturbances.

[0052] Energy Efficiency Optimization (Optional Advanced Function): During periods of stable operation and constant load, the controller can fine-tune the combination of speed and valve opening, calculate the system's unit compression work or comprehensive energy efficiency index, and find the optimal operating point under the current working conditions through optimization algorithms.

[0053] III. System Workflow and Dynamic Control Process With reference to the accompanying diagrams and control logic, describe the complete dynamic process control of the equipment from a cold start-up to stable operation, and then to responding to a load change.

[0054] 1. Cold start and initial start-up control: The operator issues the system start command, the controller records the start time, and immediately sets the operation phase flag to "initial start".

[0055] The controller invokes the "initial start control strategy," which sends a command to the drive motor inverter to start the drive motor 10 at 30% of its rated speed (n_start). At the same time, it controls the actuator of the regulating valve 11 to set the valve opening to 30%.

[0056] Evaporator 2 begins to receive feed and be heated (the heat source may come from an external source or the system itself for preheating), gradually generating low-temperature, low-pressure steam. The steam flows to compressor 3 through the first pipe 5. At this time, the T_in and P_in detected by inlet sensors 11 and 12 are very low, meeting the "initial start-up" conditions.

[0057] During this stage, compressor 3 operates at low speed and low flow rate with a very light load. The current and vibration values ​​of drive motor 10 are both low, and the system warms up slowly, avoiding the risk of liquid slugging and excessive stress on the bearings that may be caused by high-speed impact on cold steam.

[0058] 2. Transition period control to stable operation: Approximately 90 seconds later, the steam production of evaporator 2 increased, the inlet steam temperature T_in rose to 88°C, and the pressure P_in rose to 22 kPa, exceeding the threshold of "initial start-up" (85°C, 20 kPa). The operation phase identification module switched the flag to "transition period".

[0059] The adaptive control module immediately switches to the "transitional control strategy": The speed control loop starts working. Assuming T_target = 95°C, the current T_in = 88°C, and the deviation e_T = 7°C, the PID calculation generates a speed increase. At the same time, the controller calculates that dT_in / dt is approximately 0.05°C / s. Based on this, the feedforward compensation module generates an additional speed increment. The two are combined, causing the drive motor 10 to accelerate from 30% speed with a curve that is more aggressive than a simple PID response but more realistic than a fixed slope.

[0060] Valve control is coordinated with rotational speed. Following preset rules, the controller gradually opens the valve from 30% to 50%, 70%, and so on, as the rotational speed increases. As the compression ratio gradually increases, the outlet steam temperature T_out and pressure P_out begin to rise significantly.

[0061] Throughout the transition period, the controller continuously monitors all sensor data. Data from vibration and current sensors is used for safety monitoring, ensuring the acceleration process remains within mechanical and electrical safety limits. The level gauge signal is used to confirm stable evaporation conditions.

[0062] 3. Stable operation period control: About 8 minutes after startup, the inlet steam temperature T_in stabilized between 94-96°C, the pressure P_in stabilized between 29-31kPa and lasted for more than 5 minutes, the drive motor 10 current was stable and the vibration was normal. The operation phase identification module's judgment conditions were met, and the flag was switched to "stable operation period".

[0063] When the control strategy is switched to "precise feedback control", the main control objective becomes maintaining the outlet steam temperature T_out at 120°C (set value). The controller finely adjusts the speed of the drive motor 10 (e.g., fluctuating within the range of 98%-102% of the rated speed) based on the measured value of T_out. The regulating valve 11 is mainly used to fine-tune the pressure and maintain the system resistance balance.

[0064] The system then enters a state of efficient and stable continuous operation.

[0065] 4. Dynamic readjustment in response to load changes: Suppose that after 2 hours of operation, the feed concentration suddenly increases, causing the boiling point in evaporator 2 to rise. Under the same heating load, the amount of steam produced temporarily decreases, which is manifested as the inlet steam pressure P_in starting to slowly decrease.

[0066] The controller detected that P_in continuously decreased from 30kPa to 27kPa within 1 minute, exceeding the fluctuation range of the stable operation period. The operation phase identification module determined that the system had entered the "transition period" again due to load changes.

[0067] The adaptive control module re-invokes the "transition period strategy," but the initial state is high pressure. The control objective is adjusted to smoothly guide the system from the current (T_in, P_in) point to another stable point that adapts to the new load (which may require new T_target, P_target, or be calculated in real time by an advanced algorithm).

[0068] The controller may first slightly reduce the drive motor speed by 10 rpm and close the valves slightly to accommodate the temporary reduction in steam volume and prevent the compressor from approaching the surge zone. Then, based on adjustments to the evaporation system (such as increasing heating) and the recovery trend of steam parameters, the speed and valves are smoothly adjusted to seek a new stable equilibrium point. Compared to direct, forceful regulation without stage recognition, this process results in less fluctuation and a smoother recovery.

[0069] As can be seen from the detailed description above, this invention achieves intelligent and precise control of the MVR steam compressor system throughout its entire lifecycle dynamic process through careful sensor placement, operational phase identification logic, and a phased adaptive control strategy. It not only solves the problems of start-up shock and fluctuations in operating conditions, but also improves overall energy efficiency through process optimization.

[0070] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A MVR vapor compressor comprising an evaporation unit, a compression unit, a heat exchange unit, connecting pipelines and a detection control system, the compression unit comprising a compressor (3) and a driving motor (10) thereof, characterized in that, The detection control system comprises: A multi-dimensional state sensing module for real-time acquisition of system operation state data; An operation phase identification module, with a signal input end electrically connected to the multi-dimensional state sensing module, for identifying the operation phase of the current system according to the data, the operation phase at least including a start-up initial stage, a transition stage and a stable operation stage; An adaptive control module, with a signal input end electrically connected to the operation phase identification module and a control output end electrically connected to at least one of the drive motor (10) and the intake regulating device of the compressor (3); the adaptive control module pre-stores a control strategy set corresponding to different operation phases, and dynamically adjusts at least one of the rotation speed and compression ratio of the compressor (3) according to the identified operation phase.

2. A MVR vapor compressor as claimed in claim 1, wherein, The multi-dimensional state sensing module comprises: Steam parameter sensors, at least including an inlet steam temperature sensor and an inlet steam pressure sensor installed on the steam inlet side of the compressor (3), and an outlet steam temperature sensor and an outlet steam pressure sensor installed on the steam outlet side of the compressor (3); Mechanical state sensors, at least including a vibration sensor and a current sensor installed on the drive motor (10).

3. A MVR vapor compressor as claimed in claim 2, wherein, The multi-dimensional state sensing module further comprises a process state sensor, which is a liquid level meter installed on the evaporation unit, or a running time signal generated inside the detection control system.

4. The MVR vapor compressor of claim 1, wherein, The identification logic of the operation phase identification module is: The determination condition of the start-up initial stage is that at least one of the following conditions is met since the system starts: the inlet steam temperature is lower than a first temperature threshold, the inlet steam pressure is lower than a first pressure threshold, and the running time is less than a first time threshold; The determination condition of the stable operation stage is that the inlet steam temperature and pressure are continuously stable in their respective target intervals for more than a second time threshold, and the current and vibration values of the drive motor (10) are within a normal range; The transition stage is a stage that does not meet the determination condition of the start-up initial stage and has not reached the determination condition of the stable operation stage.

5. The MVR vapor compressor of claim 1, wherein, The control strategy pre-stored in the adaptive control module for the start-up initial stage includes controlling the drive motor (10) to start at an initial rotation speed lower than the rated rotation speed, and limiting the rotation speed climbing rate; at the same time, controlling the intake regulating device to maintain a small opening degree.

6. The MVR vapor compressor of claim 1, wherein, The control strategy pre-stored in the adaptive control module for the transition stage includes adopting a closed-loop feedback control based on the deviation of the inlet steam parameters from their target values, and combining a feedforward compensation based on the change rate of the inlet steam parameters, to jointly adjust the rotation speed of the drive motor (10); the opening degree of the intake regulating device and the rotation speed adjustment act in coordination.

7. A MVR vapor compressor as claimed in claim 6, wherein, In the control strategy of the transition stage, the control parameters of the closed-loop feedback control can be dynamically adjusted according to the duration of the transition stage or the closeness of the current steam parameters to the target values.

8. The MVR vapor compressor of claim 1, wherein, The pre-stored control strategy in the adaptive control module for the stable operation period includes: precise feedback control with at least one of maintaining the temperature and pressure of the outlet steam of the compressor (3) at a set value as the main target; and continuously monitoring the change trend of the inlet steam pressure and making preventive adjustment.

9. A MVR vapor compressor according to any one of claims 1-8, characterized in that, The air intake adjusting device is an adjusting valve (11) installed on the outlet pipeline of the compressor (3), or is an inlet adjustable guide vane mechanism provided in the compressor (3), or is a linkage combination of the two.

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