Tandem automobile towing compressor system and automatic surge control method

Abstract

The invention relates to the technical field of compressors, in particular to a series-connection automobile towing compressor system and an automatic surge control method. The series-connection automobile towing compressor system comprises a plurality of stages of automobile towing compressors, a plurality of temperature reduction devices, a bypass return valve, a plurality of temperature reduction adjusting valves and a plurality of orifice plate flowmeters. The problems that in the prior art, cost is high, energy consumption is large and the control effect is not ideal are effectively solved, the multiple stages of automobile dragging compressors are arranged in series and matched with the temperature reducing device and the bypass backflow valve, effective circulation and temperature control of media are achieved, cost of independently using a surge backflow valve in the prior art is reduced, and meanwhile the control effect is good. Through the arrangement of the vortex shedding flowmeter, the pressure sensor, the temperature sensor and the rotating speed sensor, the inlet flow, pressure, temperature and rotating speed of each stage of compressor are accurately measured, in combination with theoretical surge pressure ratio calculation, the surge risk is pre-judged in advance and automatically controlled, and energy consumption increase caused by premature intervention of a bypass return valve at the low rotating speed is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of compressors, in particular to a series steam-turbine compressor system and an automatic surge control method. BACKGROUND

[0002] With the rapid development of petrochemical industry, natural gas, food, heating and other industries, centrifugal compressor is more and more important in the commonly used mechanical equipment, and the requirement for compressor pressure ratio is also higher. For some power grid conditions, there are surplus steam, steam turbine is widely used as a prime mover, and steam-turbine compressor has the characteristics of high energy utilization efficiency and low operation cost compared with motor drive.

[0003] In the working condition of multiple steam-turbine compressors in series, each stage uses a separate surge backflow valve for surge control, which has the problem of high cost, and the compressor performance curve and surge point cannot be accurately obtained through tests during unit commissioning. The bypass backflow valve intervenes too early at low speed of the steam-turbine compressor, resulting in high energy consumption. In addition, there are errors in the inlet flow meters of each stage of the compressor, and the surge control effect of multiple steam-turbine compressors in series is poor.

[0004] In summary, in the working condition of multiple steam-turbine compressors in series, there are problems of high cost, high energy consumption and unsatisfactory control effect. SUMMARY

[0005] The present application relates to the technical field of compressors, in particular to a series steam-turbine compressor system and an automatic surge control method.

[0006] To achieve the above-mentioned purpose, the present application provides a series steam-turbine compressor system, which comprises multiple stages of steam-turbine compressors, multiple temperature reduction devices, a bypass backflow valve, multiple temperature reduction regulating valves and multiple orifice flow meters. The multiple stages of steam-turbine compressors are arranged in series between a compressor inlet pipeline and a compressor outlet pipeline. The temperature reduction device is arranged between each adjacent two stages of steam-turbine compressors. Each temperature reduction device is connected to a temperature reduction pipeline. The temperature reduction regulating valve and the orifice flow meter are arranged at each temperature reduction device. The bypass backflow valve is connected by a pipeline between the outlet of the last steam-turbine compressor and the inlet of the first steam-turbine compressor. A vortex flow meter, a pressure sensor and a temperature sensor are arranged in sequence at the input end of each steam-turbine compressor. A speed sensor is further arranged on each steam-turbine compressor.

[0007] Each vortex flow meter is provided with a first flow transmitter, each pressure sensor is provided with a pressure transmitter, each temperature sensor is provided with a temperature transmitter, and each speed sensor is provided with a speed transmitter.

[0008] The second flow transmitter is arranged on each of the orifice flow meters.

[0009] The application also provides a surge automatic control method for a series turbo-compressor, applied to the series turbo-compressor system as described above, comprising the following steps:

[0010] Obtaining actual running pressure ratios of the compressors, theoretical speed surge pressure ratios and theoretical flow surge pressure ratios;

[0011] Comparing the theoretical surge pressure ratios to determine the highest pressure ratio in the working area;

[0012] Comparing the actual running pressure ratios with the highest pressure ratio in the working area to determine the surge risk;

[0013] Using the surge automatic control logic to avoid the surge;

[0014] Using the vortex flow meter to limit the maximum flow of the desuperheating medium to avoid the over-spraying of the compressor when the control of the desuperheating device fails, thereby causing the system instability;

[0015] Using the pipeline flow of the inter-stage desuperheating device and the inlet flow of the compressors to compare with each other to determine the accuracy of the measurement results of the flow meters participating in the surge control.

[0016] In the step of obtaining the actual running pressure ratios of the compressors, the theoretical speed surge pressure ratios and the theoretical flow surge pressure ratios, the actual running pressure ratio of each compressor is obtained by dividing the inlet pressure of the (n+1)th turbo-compressor by the inlet pressure of the nth turbo-compressor, and the actual running pressure ratio of each compressor is denoted as ε 3n .

[0017] In the step of obtaining the actual running pressure ratios of the compressors, the theoretical speed surge pressure ratios and the theoretical flow surge pressure ratios, the calculation formula of the theoretical speed surge pressure ratio of each compressor is as follows:

[0018] ε 1n =k 1n *N+a

[0019] In the formula, ε 1n is the theoretical speed surge pressure ratio of the compressor corresponding to the nth stage, k 1n is the speed coefficient corresponding to the nth stage, N is the speed, and a is the speed constant.

[0020] In the step of obtaining the actual running pressure ratios of the compressors, the theoretical speed surge pressure ratios and the theoretical flow surge pressure ratios, the calculation formula of the theoretical flow surge pressure ratio of each compressor is as follows:

[0021] ε 2n =k 2n *Qn +b

[0022] wherein ε 2n is the theoretical surge pressure ratio of the compressor corresponding to the n-th stage, k 2n is the flow coefficient corresponding to the n-th stage, Q n is the measured inlet volume flow of the n-th stage, and b is a flow constant.

[0023] The specific content of the step of "comparing the theoretical surge pressure ratios of each stage to determine the highest pressure ratio in the working zone" is as follows:

[0024] The theoretical surge pressure ratio of the rotational speed of each stage is compared with the theoretical flow surge pressure ratio, and the lowest value is taken as the theoretical surge pressure ratio of the compressor of the stage;

[0025] The low value obtained above is subtracted by the buffer pressure ratio to obtain the highest pressure ratio in the working zone of the compressor of the stage.

[0026] The specific content of the step of "avoiding the occurrence of surge by using the surge automatic control logic" is as follows:

[0027] When it is determined that the surge of a certain stage of compressor is about to occur, the rotational speed of the compressor of the stage is first tried to be reduced within the adjustable range of the rotational speed, so as to reduce the actual running pressure ratio and make it lower than the highest pressure ratio in the working zone;

[0028] If the surge cannot be avoided after the rotational speed is reduced, part of the medium at the outlet of the last stage of compressor is returned to the inlet of the first stage of compressor by adjusting the opening of the bypass return valve, so as to increase the intake amount of the compressor and further reduce the actual running pressure ratio, and ensure that the compressor avoids the surge zone.

[0029] The specific content of the step of "limiting the maximum flow of the desuperheating medium by using the vortex flowmeter to avoid over-spraying of the compressor when the control of the desuperheating device fails" is as follows: the vortex flowmeter is used to measure the flow consumed for the desuperheating of the outlet of the compressor, and the maximum flow of the desuperheating medium is limited.

[0030] Further, the condition formula for judging the accuracy of the flowmeter is as follows:

[0031] |Q n+1 -Q n -q n |≤D

[0032] wherein Q n+1 is the inlet flow of the (n+1)-th stage of compressor, Q n is the measured inlet volume flow of the n-th stage, q n is the flow of the desuperheating device at the outlet of the n-th stage of compressor, and D is a flow difference constant. When the above condition formula is not established, the control system alarms and cuts off the rotational speed surge pressure ratio ε 1n and the flow surge pressure ratio ε 2n, actual operating pressure ratio epsilon 3n Participate in surge judgment, improve system stability.

[0033] The serial turbo-compressor system and the surge automatic control method provided by the application, comprising a multi-stage turbo-compressor, a plurality of temperature reduction devices, a bypass backflow valve, a plurality of temperature reduction regulating valves and a plurality of orifice flow meters, effectively solve the problems of high cost, high energy consumption and unsatisfactory control effect in the prior art by optimizing the configuration and control method of the serial turbo-compressor system. Specifically, the multi-stage turbo-compressors are arranged in series, and cooperate with the temperature reduction devices and the bypass backflow valve to realize effective circulation and temperature control of the medium, thereby reducing the cost of using a surge backflow valve alone in the prior art. At the same time, by arranging the orifice flow meters, the pressure sensors, the temperature sensors and the speed sensors, the inlet flow, pressure, temperature and speed of each stage of compressor are accurately measured, and in combination with the theoretical surge pressure ratio calculation, the surge risk is pre-judged and automatically controlled, thereby avoiding the increase of energy consumption caused by the early intervention of the bypass backflow valve at low speed. BRIEF DESCRIPTION OF DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0035] Figure 1 is a structure schematic diagram of the two-stage turbo-compressor in series in the serial turbo-compressor system provided by the application.

[0036] Figure 2 is a step flow chart of the surge automatic control method of the serial turbo-compressor provided by the application.

[0037] 101-turbo-compressor, 102-temperature reduction device, 103-bypass backflow valve, 104-temperature reduction regulating valve, 105-orifice flow meter, 106-vortex flow meter, 107-pressure sensor, 108-temperature sensor, 109-speed sensor, 110-first flow transmitter, 111-pressure transmitter, 112-temperature transmitter, 113-speed transmitter, 114-second flow transmitter, 115-final pressure sensor, 116-final temperature sensor, 117-final pressure transmitter, 118-final temperature transmitter. DETAILED DESCRIPTION

[0038] Embodiments of the present application are described below in the detailed description and illustrated in the accompanying drawings by using examples, in which the same or similar components or components having the same or similar functions are denoted by the same or similar reference numerals throughout. The embodiments described below by referring to the drawings are exemplary and are intended to explain the present application, and cannot be understood as a limitation of the present application.

[0039] Referring to Figure 1 The present application provides a series steam turbine compressor system, which comprises a plurality of steam turbine compressors 101, a plurality of temperature reduction devices 102, a bypass backflow valve 103, a plurality of temperature reduction regulating valves 104 and a plurality of orifice flow meters 105, the plurality of steam turbine compressors 101 are arranged in series between a compressor inlet pipeline and a compressor outlet pipeline, the temperature reduction device 102 is arranged between each adjacent two steam turbine compressors 101, each temperature reduction device 102 is connected to a temperature reduction pipeline, the temperature reduction regulating valve 104 and the orifice flow meter 105 are arranged at each temperature reduction device 102, the bypass backflow valve 103 is connected by a pipeline between the outlet of the last steam turbine compressor 101 and the inlet of the first steam turbine compressor 101, a vortex flow meter 106, a pressure sensor 107 and a temperature sensor 108 are arranged in sequence at the input end of each steam turbine compressor 101, and a rotation speed sensor 109 is further arranged on each steam turbine compressor 101.

[0040] In the present embodiment, by optimizing the series steam turbine compressor system configuration and control method, the problems of high cost, high energy consumption and poor control effect in the prior art are effectively solved. Specifically, the plurality of steam turbine compressors 101 are arranged in series, and cooperate with the temperature reduction device 102 and the bypass backflow valve 103 to realize effective circulation and temperature control of the medium, thereby reducing the cost of using a surge backflow valve alone in the prior art. At the same time, by arranging the vortex flow meter 106, the pressure sensor 107, the temperature sensor 108 and the rotation speed sensor 109, the inlet flow, pressure, temperature and rotation speed of each compressor are accurately measured, and the theoretical surge pressure ratio is calculated to realize early prediction and automatic control of the surge risk, thereby avoiding the increase of energy consumption caused by the early intervention of the bypass backflow valve 103 at low rotation speed.

[0041] Further, a first flow transmitter 110 is arranged at each vortex flow meter 106, a pressure transmitter 111 is arranged at each pressure sensor 107, a temperature transmitter 112 is arranged at each temperature sensor 108, and a rotation speed transmitter 113 is arranged at each rotation speed sensor 109.

[0042] In the embodiment, the weak signal output by the orifice plate flowmeter 105 can be amplified, processed, standardized and converted into a standardized signal suitable for remote transmission through the setting of the second flow transmitter 114.

[0043] Further, the orifice plate flowmeter 105 is provided with the second flow transmitter 114, and the orifice plate flowmeter 105 and the vortex flowmeter 106 can be replaced by Venturi or vortex flowmeters.

[0044] In the embodiment, the weak signal output by the orifice plate flowmeter 105 can be amplified, processed, standardized and converted into a standardized signal suitable for remote transmission through the setting of the second flow transmitter 114.

[0045] Further, the endmost steam turbine compressor 101 is provided with a final pressure sensor 115 and a final temperature sensor 116 between the circuit pipeline communicating with the bypass return valve 103, the final pressure sensor 115 is provided with a final pressure transmitter 117, and the final temperature sensor 116 is provided with a final temperature transmitter 118.

[0046] In the embodiment, the outlet pressure of the endmost steam turbine compressor 101 can be monitored through the setting of the final pressure sensor 115 and the final pressure transmitter 117, and the outlet temperature of the endmost steam turbine compressor 101 can be monitored through the setting of the final temperature sensor 116 and the final temperature transmitter 118.

[0047] Please refer to Figure 2 The application also provides a surge automatic control method for a series steam turbine compressor 101, which is applied to the series steam turbine compressor system as described above and includes the following steps.

[0048] Obtaining actual operation pressure ratio, theoretical rotation speed surge pressure ratio and theoretical flow surge pressure ratio of each stage compressor;

[0049] Comparing the theoretical surge pressure ratios of each stage to determine the highest pressure ratio in the working area;

[0050] Comparing the actual operation pressure ratio with the highest pressure ratio in the working area to determine the surge risk;

[0051] The surge automatic control logic is used to avoid the occurrence of surge;

[0052] The maximum flow of the temperature reducing medium is limited by the vortex flow meter to avoid the over-spraying of the compressor when the control of the temperature reducing device fails, thereby causing the system to be unstable.

[0053] The accuracy of the measurement results of the flow meters participating in the surge control is determined by comparing the pipeline flow of the inter-stage temperature reducing device and the inlet flow of each stage of compressor.

[0054] In the embodiment, by acquiring the actual operating pressure ratio of each stage of compressor in real time and comparing it with the theoretical rotating speed surge pressure ratio and the theoretical flow surge pressure ratio, it can be accurately determined whether each stage of compressor has a risk of surge, the highest pressure ratio of the working area is determined by comparing the theoretical surge pressure ratios of each stage, and a clear limit is provided for the safe operation of the compressor. When it is determined that a stage of compressor is about to occur surge, the system automatically adjusts the rotating speed of the compressor or the opening degree of the bypass return valve 103 to ensure that the compressor avoids the surge area, and the automatic control of the surge is realized.

[0055] Further, in the step of "acquiring the actual operating pressure ratio of each stage of compressor, the theoretical rotating speed surge pressure ratio and the theoretical flow surge pressure ratio", the actual operating pressure ratio of each stage of compressor is obtained by dividing the inlet pressure of the (n+1) stage of turbo-compressor 101 by the inlet pressure of the n stage of turbo-compressor 101, and the actual operating pressure ratio of each stage of compressor is denoted as ε 3n .

[0056] Further, in the step of "acquiring the actual operating pressure ratio of each stage of compressor, the theoretical rotating speed surge pressure ratio and the theoretical flow surge pressure ratio", the calculation formula of the theoretical surge rotating speed pressure ratio of the first stage of compressor is:

[0057] ε 1n =k 1n *N+a

[0058] In the formula, ε 1n is the corresponding n stage of theoretical surge rotating speed pressure ratio of the compressor, k 1n is the corresponding n stage of rotating speed coefficient, N is the rotating speed, and a is the rotating speed constant.

[0059] Further, in the step of "acquiring the actual operating pressure ratio of each stage of compressor, the theoretical rotating speed surge pressure ratio and the theoretical flow surge pressure ratio", the calculation formula of the theoretical flow surge pressure ratio of each stage of compressor is:

[0060] ε 2n =k 2n *Q n +b

[0061] In the formula, ε 2nk is the theoretical surge flow pressure ratio of the compressor corresponding to level n, 2n is the flow coefficient corresponding to level n, Q n is the measured inlet volume flow rate of this stage, and b is the flow constant.

[0062] Furthermore, the specific content of the step "comparing the theoretical surge pressure ratios of each level and determining the maximum pressure ratio of the working area" is:

[0063] Compare the theoretical speed surge pressure ratio of each stage with the theoretical flow surge pressure ratio, and take the lowest value as the theoretical surge pressure ratio of the compressor at that stage;

[0064] Subtract the buffer pressure ratio from the low value obtained above to obtain the maximum pressure ratio of the working area of ​​the compressor at this stage.

[0065] In this embodiment, by comparing the theoretical speed surge pressure ratio and the theoretical flow surge pressure ratio of each stage of the compressor, and taking the lower value of the two as the theoretical surge pressure ratio, this approach ensures that the setting of the surge threshold is more accurate, avoiding misjudgment that may be caused by a single factor, and further subtracting the buffer pressure ratio from the low value of the theoretical surge pressure ratio to obtain the highest pressure ratio in the working area. This step reserves a margin for the safe operation of the compressor, ensuring that in actual operation, even if certain fluctuations occur, the compressor can remain in the safe working area, effectively preventing the occurrence of surge. By accurately determining the surge threshold and considering the safety margin, the technical solution significantly improves the safety of the series steam-driven compressor system, reduces the surge risk, and ensures the stable operation of the equipment.

[0066] Furthermore, the specific contents of the step "using surge automatic control logic to avoid surge occurrence" are:

[0067] When it is determined that a certain compressor stage is about to surge, first try to reduce the speed of the compressor stage within the adjustable speed range to reduce the actual operating pressure ratio to below the maximum pressure ratio in the working area;

[0068] If surge cannot be avoided even after reducing the speed, part of the medium at the outlet of the last-stage compressor is returned to the inlet of the first-stage compressor by adjusting the opening of the bypass return valve 103 to increase the compressor intake volume, further reduce the actual operating pressure ratio, and ensure that the compressor avoids the surge zone.

[0069] Furthermore, the vortex flowmeter 106 is used to measure the flow consumed by the outlet desuperheating of the corresponding compressor and to limit the maximum flow of the desuperheating medium;

[0070] Furthermore, the conditional formula for judging the accuracy of the flow meter is:

[0071] |Q n+1 -Q n -q n |≤D

[0072] In the formula, Q n+1 is the (n+1) stage compressor inlet flow, Q n is the n stage measured inlet volume flow, q n is the n stage compressor outlet desuperheating device flow, D is a flow difference constant, when the above condition formula is not established, the control system alarms, and the speed of the stage is removed from the surge pressure ratio ε 1n , the flow surge pressure ratio ε 2n , the actual operation pressure ratio ε 3n participate in the surge judgment, and improve the system stability.

[0073] In the embodiment, when the system determines that the surge of the compressor is about to occur, measures can be taken immediately, first trying to reduce the speed of the compressor within the speed adjustable range, the rapid response mechanism effectively shortens the response time before the surge occurs, and by reducing the compressor speed, the actual operation pressure ratio is reduced, which is lower than the maximum pressure ratio in the working area. This adjustment method is flexible and effective, which can smoothly adjust the operation state of the compressor without interrupting the system operation, avoids the occurrence of surge, and at the same time, if the surge cannot be avoided after reducing the speed, the system further adjusts the opening of the bypass return valve 103 to return part of the medium at the outlet of the last stage compressor to the inlet of the first stage compressor to increase the intake amount of the compressor. This double protection mechanism ensures that even in extreme cases, the occurrence of surge can be effectively avoided, and the stable operation of the system is ensured.

[0074] Further, the whole series of diesel engine-driven compressor 101 adopts Siemens S7-1500 series DEH control system, the flow, temperature, pressure, speed feedback, valve feedback and other signals enter the DEH control system analog input module, the speed given, valve opening given and other signals are output by the DEH control system analog output module, and the control and display of the system are carried out on the matching upper computer operator station.

[0075] The above only discloses one preferred embodiment of the present application, and of course cannot limit the scope of the present application, and those skilled in the art can understand that all or part of the above-mentioned embodiments can be implemented, and equivalent changes made according to the claims of the present application still belong to the scope covered by the present application.

Claims

1. A series steam-driven compressor system, characterized in that: It includes a multi-stage steam-driven compressor, multiple temperature reduction devices, a bypass return valve, multiple temperature reduction regulating valves and multiple orifice flow meters. The multiple stages of the steam-driven compressor are arranged in series between the compressor inlet pipe and the compressor outlet pipe. The temperature reduction device is provided between each two adjacent stages of the steam-driven compressors. Each of the temperature reduction devices is connected to the temperature reduction pipe. Each temperature reduction device is provided with the temperature reduction regulating valve and the orifice flow meter. The bypass return valve is connected between the outlet of the steam-driven compressor at the end and the inlet of the steam-driven compressor at the front end through a pipe. A vortex flowmeter, a pressure sensor and a temperature sensor are sequentially provided at the input end of each stage of the steam-driven compressor. A speed sensor is also provided on each stage of the steam-driven compressor.

2. The tandem steam-driven compressor system according to claim 1, characterized in that: Each of the vortex flowmeters is provided with a first flow transmitter, each of the pressure sensors is provided with a pressure transmitter, each of the temperature sensors is provided with a temperature transmitter, and each of the speed sensors is provided with a speed transmitter.

3. The tandem steam-driven compressor system according to claim 2, characterized in that: Each of the orifice flowmeters is provided with a second flow transmitter, and both the orifice flowmeter and the vortex flowmeter can be replaced by a Venturi or vortex flowmeter.

4. A method for automatically controlling surge of a series steam-driven compressor, applied to the series steam-driven compressor system according to claim 1, characterized in that: The steps include: Obtain the actual operating pressure ratio, theoretical speed surge pressure ratio and theoretical flow surge pressure ratio of each compressor level; Compare the theoretical surge pressure ratios of each level to determine the highest pressure ratio in the working area; Compare the actual operating pressure ratio with the maximum pressure ratio in the working area to determine the surge risk; Use surge automatic control logic to avoid surge; Use vortex flowmeter to limit the maximum flow of cooling medium to avoid excessive spraying on the compressor when cooling device control fails, which may cause system instability; The accuracy of the measurement results of the flowmeter involved in surge control is determined by comparing the flow rate of the interstage desuperheater pipeline and the inlet flow rate of each stage compressor.

5. The method for automatically controlling surge of a series steam-driven compressor according to claim 4, wherein: In the step of "obtaining the actual operating pressure ratio, theoretical speed surge pressure ratio and theoretical flow surge pressure ratio of each compressor", the actual operating pressure ratio of each compressor is obtained by dividing the inlet pressure of the (n+1) stage steam-driven compressor by the inlet pressure of the n stage steam-driven compressor. The actual operating pressure ratio of each compressor is calculated as ε 3n .

6. The method for automatically controlling surge of a series steam-driven compressor according to claim 5, characterized in that: In the step "obtaining the actual operating pressure ratio, theoretical speed surge pressure ratio, and theoretical flow surge pressure ratio of each compressor stage," the calculation formula for the theoretical surge speed pressure ratio of each compressor stage is: e 1n =k 1n *N+a Where, ε 1n k is the theoretical surge speed-pressure ratio of the compressor corresponding to level n, 1n is the speed coefficient corresponding to level n, N is the speed, and a is the speed constant.

7. The method for automatically controlling surge of a series steam-driven compressor according to claim 6, wherein: In the step "obtaining the actual operating pressure ratio, theoretical speed surge pressure ratio, and theoretical flow surge pressure ratio of each compressor level," the calculation formula for the theoretical flow surge pressure ratio of each compressor level is: ε 2n =k 2n *Q n +b Where, ε 2n k is the theoretical surge flow pressure ratio of the compressor corresponding to level n, 2n is the flow coefficient corresponding to level n, Q n is the measured inlet volume flow rate of this stage, and b is the flow constant.

8. The method for automatically controlling surge of a series steam-driven compressor according to claim 7, wherein: The specific contents of the step "Compare the theoretical surge pressure ratios at each level and determine the maximum pressure ratio in the working area" are as follows: Compare the theoretical speed surge pressure ratio of each stage with the theoretical flow surge pressure ratio, and take the lowest value as the theoretical surge pressure ratio of the compressor at that stage; Subtract the buffer pressure ratio from the low value obtained above to obtain the maximum pressure ratio of the working area of ​​the compressor at this stage.

9. The method for automatically controlling surge of a series steam-driven compressor according to claim 8, wherein: The specific contents of the step "Using surge automatic control logic to avoid surge occurrence" are as follows: When it is determined that a certain compressor stage is about to surge, first try to reduce the speed of the compressor stage within the adjustable speed range to reduce the actual operating pressure ratio to below the maximum pressure ratio in the working area; If surge cannot be avoided after reducing the speed, part of the medium at the outlet of the last-stage compressor is returned to the inlet of the first-stage compressor by adjusting the opening of the bypass return valve to increase the compressor intake volume, further reduce the actual operating pressure ratio, and ensure that the compressor avoids the surge zone.

10. The method for automatically controlling surge of a series steam-driven compressor according to claim 9, wherein: The specific content of the step "using a vortex flowmeter to limit the maximum flow rate of the desuperheating medium to avoid excessive spraying of the compressor when the desuperheating device control fails" is: using the vortex flowmeter to measure the flow rate consumed by the desuperheating of the corresponding compressor outlet and limit the maximum flow rate of the desuperheating medium; Furthermore, the conditional formula for judging the accuracy of the flow meter is: |Q n+1 -Q n -q n |≤D Where Q n+1 is the inlet flow of the (n+1) stage compressor, Q n is the measured inlet volume flow rate of level n, q n is the outlet flow of the n-stage compressor desuperheater, D is the flow difference constant, when the above conditional formula is not established, the control system alarms and cuts off the speed surge pressure ratio ε of this stage 1n , flow surge pressure ratio ε 2n , actual operating pressure ratio ε 3n Participate in surge judgment and improve system stability.

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