A method and apparatus for controlling an axial compressor provided with inter-stage bleeding

Abstract

The present application is suitable for the compressor anti-surge control field, and provides a control method and device of axial flow compressor with inter-stage bleeding. In the embodiment, for the axial flow compressor with inter-stage bleeding, a start-stop control line group and a continuous operation control line group are set in advance according to the surge boundary and surge margin of the compressor. When the compressor is running, the matched control line group is determined according to the operation parameters, running state and switch state of the inter-stage bleeding valve of the compressor. Then, the valves of the compressor, such as the exhaust air supply valve, the exhaust air vent valve and the inter-stage bleeding valve, are adjusted according to the pressure ratio, equivalent speed and inlet guide vane opening of the compressor, so as to avoid the unstable operation of the compressor and the problems of possible stall or surge.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of compressor anti-surge control, and in particular to a control method and device for an axial flow compressor provided with inter-stage bleeding. BACKGROUND

[0002] In modern industrial production, compressors are an important equipment, widely used in various occasions requiring compression of gas, such as petroleum, chemical industry, metallurgy, power, machinery manufacturing, etc. Among them, axial flow compressors are widely used in large-scale industrial production due to their simple structure, high efficiency, large flow and other advantages. However, the operating characteristics of axial flow compressors are complex, and their operating state is affected by many factors, such as inlet temperature, downstream process gas demand, adjustable guide vane / stator vane opening, etc. Therefore, how to effectively control the operating state of the axial flow compressor to ensure its efficient and stable operation is an important research topic.

[0003] The existing anti-surge control strategy for axial flow compressors mainly prevents the compressor from surging during start-up and shutdown through full stator adjustable. However, during continuous operation, the axial flow compressor is controlled by anti-surge valve and vent valve to prevent the unit from surging during operation.

[0004] Although the existing control method of axial flow compressor can meet the demand to some extent, there are still some problems.

[0005] Firstly, the existing control strategy is not suitable for high pressure ratio axial flow compressor units provided with inter-stage bleeding. The performance parameters of the unit monitored by the existing control strategy are throat differential pressure and discharge pressure: the throat differential pressure can reflect the inlet flow of the compressor, but in the high pressure ratio compressor unit provided with inter-stage bleeding, the inlet flow corresponding to the compressor operating state is not unique due to the existence of inter-stage bleeding. The discharge pressure can reflect the pressure ratio of the compressor, but in the high pressure ratio large margin axial flow compressor unit, the compressor pressure ratio corresponding to the discharge pressure is not unique due to the change of inlet pressure loss.

[0006] Secondly, the existing control strategy describes the state of the compressor unit singlely. It cannot cope with the control line changes of high pressure ratio large margin axial flow compressor unit at constant speed, variable adjustable inlet guide vane opening state; it cannot describe the control line changes of high pressure ratio large margin axial flow compressor unit before and after the opening of inter-stage bleeding valve during start-up and shutdown.

[0007] Finally, for high pressure ratio large margin axial flow compressor units provided with inter-stage bleeding, the existing control strategy lacks operation and control of inter-stage bleeding related valves, and cannot cope with the start-up and abnormal control of such compressor units. SUMMARY

[0008] Therefore, the application provides an axial flow compressor control method and device with inter-stage bleeding to solve the problem that the existing axial flow compressor control method lacks operation and control of the inter-stage bleeding related valves and is not suitable for the compressor set.

[0009] The first aspect of the application provides an axial flow compressor control method with inter-stage bleeding. The compressor includes an inter-stage bleeding valve and a plurality of other valves and corresponding ventilation pipelines. The compressor is provided with a control line group set by a preset surge boundary. The control line group includes a start-stop control line group and a continuous operation control line group. The method includes:

[0010] Determining the operating parameters and operating state of the compressor. The operating parameters include compressor inlet total pressure, compressor outlet total pressure, physical speed, compressor inlet total temperature, and inlet guide vane opening. The operating state includes the start-up process, continuous operation, and shutdown process.

[0011] Determining the compression ratio of the compressor by the compressor inlet total pressure and compressor outlet total pressure in the operating parameters. Determining the equivalent speed according to the physical speed and inlet total temperature of the compressor. Adjusting the on-off state of the inter-stage bleeding valve according to the equivalent speed and the operating state.

[0012] Determining the currently matched control line group of the compressor by the operating parameters, operating state, and on-off state of the inter-stage bleeding valve.

[0013] When the compressor matches the start-stop control line group, adjusting the plurality of other valves of the compressor according to the equivalent speed, compression ratio, and start-stop control line group.

[0014] When the compressor matches the continuous operation control line group, adjusting the plurality of other valves of the compressor according to the inlet guide vane opening, compression ratio, and continuous operation control line group.

[0015] Optionally, the surge boundary includes a first surge boundary and a second surge boundary. The first surge boundary is used to represent the maximum compression ratio of the compressor at different equivalent speeds. The second surge boundary is used to represent the maximum compression ratio of the compressor at different inlet guide vane openings at the rated speed. The compressor is pre-set with a surge margin of each control line in the control line group.

[0016] The control line group set by the preset surge boundary and surge margin includes:

[0017] Determining a first surge line SL according to a preset first surge boundary. The first surge boundary is used to represent the maximum compression ratio of the compressor at different equivalent speeds.

[0018] determining other first surge control lines according to the first surge margin and the first surge line SL, wherein the other first surge control lines comprise a first surge light control line LCL, a first surge medium control line MCL and a first surge strong control line SCL;

[0019] the first surge line SL and the other first surge control lines form the start-stop control line group;

[0020] determining a second surge line SL according to a preset second surge boundary, wherein the second surge boundary is used to represent a maximum compression ratio of the compressor at a rated speed and different inlet guide vane openings;

[0021] determining other second surge control lines according to a second surge margin and the second surge line SL, wherein the other second surge control lines comprise a second surge light control line LCL, a second surge medium control line MCL and a second surge strong control line SCL;

[0022] the second surge line SL and the other second surge control lines form the continuous operation control line group.

[0023] Optionally, the several other valves comprise an exhaust air supply valve and an exhaust air vent valve, and the method further comprises:

[0024] when the compressor is continuously operated at the rated speed, detecting a gas supply demand of a downstream process, and adjusting the exhaust air supply valve, the exhaust air vent valve and the inlet adjustable guide vane opening according to the gas supply demand, wherein the gas supply demand comprises a gas supply pressure demand and a gas supply flow demand.

[0025] Optionally, the determining of the other first surge control lines according to the first surge margin and the first surge line SL comprises:

[0026] by calculating a control line compression ratio of the other first surge control lines at different equivalent speeds, and determining corresponding other first surge control lines according to the control line compression ratio and the equivalent speed, wherein, the control line compression ratio of the first surge line SL at the equivalent speed, the the control line compression ratio of the other first surge control lines at the equivalent speed, and the SM is a surge margin.

[0027] Optionally, the several other valves comprise an exhaust air supply valve, and the method further comprises:

[0028] controlling the exhaust air supply valve and the exhaust air vent valve to cut off the connection between the compressor and a downstream process before the compressor starts or stops.

[0029] The second aspect of the present application provides a control device for an axial compressor with inter-stage bleed, the compressor comprising an inter-stage bleed valve and several other valves and corresponding venting pipelines, and the compressor being provided with a control line group by preset surge boundaries, the control line group comprising a start-stop control line group and a continuous operation control line group; the device comprising:

[0030] a parameter state determining unit for determining operating parameters and operating states of the compressor, wherein the operating parameters comprise compressor inlet total pressure, compressor outlet total pressure, physical rotational speed, compressor inlet total temperature and inlet guide vane opening, and the operating states comprise a start-up process, continuous operation and a shutdown process;

[0031] a rotational speed and pressure ratio determining unit for determining a pressure ratio of the compressor by the compressor inlet total pressure and the compressor outlet total pressure among the operating parameters, determining a reduced rotational speed according to the physical rotational speed and the inlet total temperature of the compressor, and adjusting an on-off state of the inter-stage bleed valve according to the reduced rotational speed and the operating state;

[0032] a control line group matching unit for determining a currently matched control line group of the compressor according to the operating parameters, the operating state and the on-off state of the inter-stage bleed valve;

[0033] a first adjusting unit for adjusting several other valves of the compressor according to the reduced rotational speed, the pressure ratio and the start-stop control line group when the compressor matches the start-stop control line group;

[0034] a second adjusting unit for adjusting several other valves of the compressor according to the inlet guide vane opening, the pressure ratio and the continuous operation control line group when the compressor matches the continuous operation control line group.

[0035] Optionally, the surge boundaries comprise a first surge boundary and a second surge boundary, wherein the first surge boundary is used to represent a maximum pressure ratio of the compressor at different reduced rotational speeds, and the second surge boundary is used to represent a maximum pressure ratio of the compressor at different inlet guide vane openings at a rated rotational speed; the compressor is provided with a surge margin of each control line in the control line group in advance;

[0036] the control line group being provided by preset surge boundaries and surge margins comprises:

[0037] determining a first surge line SL according to a preset first surge boundary, wherein the first surge boundary is used to represent a maximum pressure ratio of the compressor at different reduced rotational speeds;

[0038] determining other first surge control lines according to the first surge margin and the first surge line SL, wherein the other first surge control lines comprise a first surge light control line LCL, a first surge medium control line MCL and a first surge strong control line SCL;

[0039] composing the start-stop control line group by the first surge line SL and the other first surge control lines;

[0040] determining a second surge line SL according to a preset second surge boundary, wherein the second surge boundary is used to represent a maximum pressure ratio of the compressor at a rated rotating speed and different inlet guide vane openings;

[0041] determining other second surge control lines according to a second surge margin and the second surge line SL, wherein the other second surge control lines comprise a second surge light control line LCL, a second surge medium control line MCL and a second surge strong control line SCL;

[0042] composing the continuous operation control line group by the second surge line SL and the other second surge control lines.

[0043] Optionally, the several other valves comprise an exhaust air supply valve and an exhaust air vent valve, and the device further comprises:

[0044] an other valve adjusting unit, configured to detect a gas supply demand of a downstream process when the compressor is continuously operated at the rated rotating speed, and adjust the exhaust air supply valve, the exhaust air vent valve and the inlet adjustable guide vane opening according to the gas supply demand, wherein the gas supply demand comprises a gas supply pressure demand and a gas supply flow demand.

[0045] Optionally, the determining the other first surge control lines according to the first surge margin and the first surge line SL comprises:

[0046] composing the first surge line SL and the other first surge control lines by calculating a control line pressure ratio of the other first surge control lines at different equivalent rotating speeds, and determining corresponding other first surge control lines according to the control line pressure ratio and the equivalent rotating speed, wherein the control line pressure ratio of the first surge line SL at the equivalent rotating speed, the SM is a surge margin. the control line pressure ratio of the other first surge control lines at the equivalent rotating speed, the SM is a surge margin.

[0047] Optionally, the several other valves comprise an exhaust air supply valve, and the device further comprises:

[0048] an independent start-stop unit, configured to control the exhaust air supply valve and the exhaust air vent valve to cut off the connection between the compressor and a downstream process before the compressor starts or stops.

[0049] In the embodiments provided in the present application, for the axial compressor provided with inter-stage bleeding, a start-stop control line group and a continuous operation control line group are set in advance according to the surge boundary and surge margin of the compressor, when the compressor is running, first, the matching control line group is determined according to the operating parameters, running state and switch state of the inter-stage bleeding valve of the compressor; then, the valves of the compressor, such as the exhaust air supply valve, exhaust air vent valve and inter-stage bleeding valve, are adjusted according to the pressure ratio, equivalent speed and inlet guide vane opening of the compressor, so as to avoid the unstable operation of the compressor and the problems such as possible stall or surge. BRIEF DESCRIPTION OF DRAWINGS

[0050] Figure 1 Method flowchart provided in the embodiments of the present application;

[0051] Figure 2 Schematic diagram of the start-stop control line group;

[0052] Figure 3 Schematic diagram of the continuous operation control line group;

[0053] Figure 4 Schematic diagram of the anti-surge control strategy;

[0054] Figure 5 Structural diagram of the device provided in the embodiments of the present application; DETAILED DESCRIPTION

[0055] The exemplary embodiments will be described in detail herein with reference to the attached drawings. The following description is only exemplary and is not intended to limit the scope, applicability or configuration of the application. Rather, the following description is intended to describe some exemplary embodiments consistent with the present application and is not intended to limit the scope, applicability or configuration of the application. Various changes can be made in the embodiments and details of the application described herein without departing from the scope of the application as defined by the appended claims.

[0056] The terminology used in the present application is only used to describe specific embodiments and is not intended to limit the scope of the present application. In the present application and the appended claims, the singular forms "a", "an" and "the" are also intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein means any or all possible combinations of one or more associated listed items.

[0057] It should be understood that although the terms first, second, third, etc., may be used in this application to describe various information, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0058] This application provides a control method and apparatus for an axial compressor with interstage venting, to solve the problem that existing axial compressor control methods lack operation and control of interstage venting valves and are not applicable to this type of compressor unit.

[0059] The technical solutions of this application will be described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.

[0060] like Figure 1 The diagram shows a flowchart of a control method for an axial compressor with interstage venting provided in this application. The compressor includes an interstage venting valve, several other valves, and corresponding ventilation pipes. The compressor is equipped with a control line group through a preset surge boundary. The control line group includes a start-stop control line group and a continuous operation control line group.

[0061] In this embodiment, other valves include exhaust air supply valves, exhaust venting coarse adjustment valves, exhaust venting fine adjustment valves, etc. The corresponding ventilation pipelines include exhaust venting pipelines, exhaust air supply pipelines, and interstage venting pipelines. Surge boundaries include surge boundaries during startup and shutdown, as well as surge boundaries at rated speed. The surge boundaries during startup and shutdown are the maximum pressure ratio of the compressor at various equivalent speeds; therefore, the abscissa of each control line in the startup / shutdown control line group is the equivalent speed, and the ordinate is the compressor pressure ratio. The surge boundaries at rated speed are the maximum pressure ratio at different inlet guide vane openings; therefore, the abscissa of each control line in the continuous operation control line group is the inlet guide vane opening, and the ordinate is the compressor pressure ratio.

[0062] In the control line group, the surge line SL is the surge boundary. The other control lines are offset downwards from this surge boundary, that is, the corresponding pressure ratio is reduced at the same equivalent speed. For example, an offset of 5% serves as an emergency control line, 20% as a mild control line, and so on.

[0063] In another embodiment, the surge boundary comprises a first surge boundary and a second surge boundary, wherein the first surge boundary is used to represent the maximum pressure ratio of the compressor at different corrected speeds, and the second surge boundary is used to represent the maximum pressure ratio of the compressor at different inlet guide vane openings at rated speed; the compressor is pre-configured with surge margins for each control line in the control line group;

[0064] The control line group set by the pre-configured surge boundary comprises:

[0065] A first surge line SL is determined according to the pre-configured first surge boundary, and other first surge control lines are determined according to the surge margin and the first surge line SL, wherein the other first surge control lines comprise a first surge light control line LCL, a first surge medium control line MCL and a first surge strong control line SCL;

[0066] The first surge line SL and the other first surge control lines form the start-stop control line group;

[0067] A second surge line SL is determined according to the pre-configured second surge boundary, and other second surge control lines are determined according to the surge margin and the second surge line SL, wherein the other second surge control lines comprise a second surge light control line LCL, a second surge medium control line MCL and a second surge strong control line SCL;

[0068] The second surge line SL and the other second surge control lines form the continuous operation control line group.

[0069] In this embodiment, a corresponding surge margin is pre-configured for each control line, such as 15% for the surge light control line LCL, 10% for the surge medium control line MCL and 5% for the surge strong control line SCL. Then the pressure ratio of each control line under the same condition is calculated by the formula , so as to determine the corresponding control line. Wherein, is the pressure ratio of the surge line, is the pressure ratio of the control line, and SM is the surge margin.

[0070] For example, for the control line in the start-stop control line group, is the pressure ratio of the first surge line SL at different corrected speeds, which can be calculated and determined according to the above formula, so as to determine the control line under each surge margin according to the corrected speed and the pressure ratio. The specific start-stop control line group is shown in Figure 2 .

[0071] Similarly, for the control lines in the continuous operation control line group, the compressor speed is at a fixed rated speed. Therefore, the second surge boundary is the maximum pressure ratio of the compressor at different inlet guide vane openings at the rated speed. This represents the pressure ratio of the second surge line SL under different inlet guide vane openings. The pressure ratio corresponding to this inlet guide vane opening can be calculated using the above formula, and thus the control lines for each surge margin can be determined based on the inlet guide vane opening and the pressure ratio. A schematic diagram of the specific continuous operation control line group is shown below. Figure 3 As shown.

[0072] After determining the control line group, the steps of the above-mentioned control method for an axial flow compressor with interstage venting are as follows:

[0073] Step S101: Determine the operating parameters and operating status of the compressor. The operating parameters include the compressor inlet total pressure, compressor outlet total pressure, physical speed, compressor inlet total temperature, and inlet guide vane opening. The operating status includes the start-up process, continuous operation, and shutdown process.

[0074] In this embodiment, various operating parameters of the compressor can be determined using various sensors or other detection devices. The operating status can be determined by commands received by the compressor (such as start / stop commands), the converted speed, and the preset rated speed. The converted speed is determined by the physical speed and the compressor inlet total temperature. When the compressor's converted speed does not reach the rated speed, it is determined that the compressor is in the start-up or shutdown process; when the converted speed reaches the rated speed, it is determined that it is in continuous operation.

[0075] Step S102: Determine the compressor pressure ratio using the compressor inlet total pressure and compressor outlet total pressure in the operating parameters; determine the equivalent speed based on the compressor's physical speed and inlet total temperature; and adjust the opening and closing state of the interstage vent valve using the equivalent speed and the operating state.

[0076] In this embodiment, through the formula Determine the compressor's pressure ratio in this formula. This refers to the total pressure at the compressor inlet. This is the total outlet pressure of the compressor.

[0077] Through formula Determine the compressor's equivalent speed, where n is the physical speed in the formula, in r / min; To compress the total temperature of the compressor inlet, unit K. When the operating state of the compressor is the starting state, and the equivalent speed reaches the preset value, such as 90% of the rated speed, the inter-stage bleed valve is closed, the speed is increased to the rated speed, and the unit reaches the air load working state. Then, by simultaneously controlling the exhaust air venting coarse adjustment valve and the exhaust air supply valve, the flow distribution of the exhaust air venting pipeline and the exhaust air supply pipeline is gradually adjusted, and the high-pressure exhaust of the compressor unit is led to the downstream process. Then, by changing the opening of the inlet adjustable guide vane, the exhaust flow of the compressor is controlled. At the same time, by reducing the flow capacity of the exhaust air supply pipeline or the flow resistance of the downstream process, the exhaust pressure of the compressor unit is increased until the rated speed of the unit is reached.

[0078] Step S103, determining the control line group currently matched by the compressor through the operating parameter, the operating state and the on-off state of the inter-stage bleed valve.

[0079] In this embodiment, the specific determination of the control line group currently matched by the compressor is as follows:

[0080] 1. Match the start-stop control line group:

[0081] During the start-up process of the unit, that is, the operating state is the start-up process, and the on-off state of the inter-stage bleed valve is open, the compressor unit matches the start-stop control line group as the anti-surge control line;

[0082] During the shutdown process of the unit, that is, the operating state is the shutdown process, and the on-off state of the inter-stage bleed valve is open, the compressor unit matches the start-stop control line group as the anti-surge control line.

[0083] 2. Match the continuous operation control line group:

[0084] During the start-up process of the unit, and the on-off state of the inter-stage bleed valve is closed, the compressor unit matches the continuous operation control line group as the anti-surge control line;

[0085] During the shutdown process of the unit, and the on-off state of the inter-stage bleed valve is closed, the compressor unit matches the continuous operation control line group as the anti-surge control line;

[0086] During the continuous operation process of the unit at rated speed, the compressor unit matches the continuous operation control line group as the anti-surge control line.

[0087] When the compressor matches the start-stop control line group, step S104A is executed; when it matches the continuous operation control line group, step S104B is executed.

[0088] Step S104A, when the compressor matches the start-stop control line group, adjusting a plurality of other valves of the compressor according to the equivalent speed, the pressure ratio and the start-stop control line group.

[0089] In this embodiment, the control line reached by the compressor train is determined and adjusted according to the equivalent speed of the compressor and the pressure ratio. When the train state exceeds the mild surge control line LCL but does not reach the moderate surge control line MCL, the PI controller of the control system is activated to target the mild surge control line LCL and adjust the exhaust air bleed fine control valve to reduce the train state below the mild surge control line LCL. When the train state exceeds the moderate surge control line MCL but does not reach the severe surge control line SCL, the exhaust air bleed fine control valve is continuously opened by 5% until the train state is reduced below the mild surge control line LCL. When the train state exceeds the severe surge control line SCL but does not reach the surge line SL, the exhaust air bleed coarse control valve is opened by 10% and the exhaust air bleed fine control valve is opened by 5%. When the train state further rises to the surge line SL, the exhaust air bleed coarse control valve is fully opened, the exhaust air bleed fine control valve is fully opened, and the speed is stopped or continues to be reduced for the operator to handle.

[0090] Step S104B, when the compressor matches the continuous operation control line set, the inlet guide vane opening, the pressure ratio, and the continuous operation control line set are used to adjust several other valves of the compressor.

[0091] In this embodiment, when the train state exceeds the mild surge control line LCL but does not reach the moderate surge control line MCL, the PI controller of the control system is activated to target the mild surge control line LCL and adjust the exhaust air bleed fine control valve to reduce the train state below the mild surge control line LCL. When the train state exceeds the moderate surge control line MCL but does not reach the severe surge control line SCL, the exhaust air bleed fine control valve is continuously opened by 5% until the train state is reduced below the mild surge control line LCL. When the train state exceeds the severe surge control line SCL but does not reach the surge line SL, the exhaust air bleed coarse control valve is opened by 15% and the exhaust air bleed fine control valve is opened by 5%. When the train state further rises to the surge line SL, the exhaust air bleed coarse control valve is opened to 50% opening, the exhaust air bleed fine control valve is fully opened, and the inter-stage bleed valve is fully opened for the operator to handle manually.

[0092] In another embodiment, the above method further comprises: before the compressor starts or stops, controlling the exhaust air supply valve and the exhaust air bleed valve to cut off the connection between the compressor and the downstream process flow.

[0093] In this embodiment, before starting the speed-up, the connection between the compressor train and the downstream process flow is cut off by closing the exhaust air supply valve, thereby ensuring independent start of the train.

[0094] Before stopping the speed-down, the flow distribution of the exhaust air bleed pipeline and the exhaust air supply pipeline is gradually adjusted by simultaneously controlling the exhaust air bleed coarse control valve and the exhaust air supply valve, the exhaust air supply valve is closed to cut off the connection between the compressor train and the downstream process flow while maintaining the exhaust pressure of the compressor, thereby ensuring independent stop of the train.

[0095] The embodiment switches the exhaust air exhaust pipeline and the exhaust air supply pipeline by controlling the exhaust air supply valve and the exhaust air exhaust valve, ensures independent start and stop of the unit, and can more accurately control the start and stop process of the compressor, and avoids occurrence of phenomena such as stall or surge.

[0096] At this point, the flowchart shown is completed. Figure 1

[0097] In the embodiment, for the axial flow compressor provided with inter-stage bleeding, a start and stop control line group and a continuous running control line group are set in advance according to the surge boundary and the surge margin of the compressor, when the compressor is running, the matching control line group is determined according to the running parameters, the running state and the opening and closing state of the inter-stage bleeding valve of the compressor, and then the valves of the compressor, such as the exhaust air supply valve, the exhaust air exhaust valve and the inter-stage bleeding valve, are adjusted according to the pressure ratio, the equivalent speed and the inlet guide vane opening of the compressor, so that the unstable running of the compressor and the problems such as stall or surge that may occur are avoided.

[0098] The above method is described below through a specific embodiment, and a schematic diagram of the anti-surge control strategy in the embodiment is shown in Figure 4 The specific implementation steps are as follows:

[0099] Step 1: Based on the strategy requirements, the required air pipelines and corresponding valves are set on the periphery of the axial flow compressor unit.

[0100] ① Inter-stage bleeding pipeline and inter-stage bleeding valve: divided into three routes of low pressure, medium pressure and high pressure, and the total pipe diameter is DN150 to DN250. The valve is selected as an adjustable valve.

[0101] ② Exhaust air exhaust pipeline and exhaust air exhaust coarse adjustment valve and exhaust air exhaust fine adjustment valve: the pipe diameter of the exhaust air exhaust coarse adjustment valve is DN400 to DN500, and the pipe diameter of the exhaust air exhaust fine adjustment valve is DN200 to DN250. The exhaust air exhaust coarse adjustment valve and the exhaust air exhaust fine adjustment valve are adjustable valves.

[0102] ③ Exhaust air supply pipeline and exhaust air supply valve: the pipe diameter is DN600 to DN1000. The exhaust air supply valve is an adjustable valve.

[0103] Step 2: Set two groups of control lines in the control system: “start and stop control line group” and “continuous running control line group”.

[0104] ​"Start-up and shut-down control line set": The control line has the converted speed as the horizontal coordinate and the pressure ratio of the compressor as the vertical coordinate. The surge line SL is the actual surge boundary of the unit during start-up and shut-down, the surge strength control line SCL reserves 2% surge margin, the surge medium control line MCL reserves 5% surge margin, and the surge light control line LCL reserves 10% surge margin.

[0105] "Continuous operation control line set": The control line has the inlet guide vane opening as the horizontal coordinate and the pressure ratio of the compressor as the vertical coordinate. The surge line SL is the actual surge boundary of the unit at the rated speed, the surge strength control line SCL reserves 2% surge margin, the surge medium control line MCL reserves 5% surge margin, and the surge light control line LCL reserves 10% surge margin.

[0106] Step three: Close the exhaust air supply valve to cut off the connection between the compressor unit and the downstream process.

[0107] Step four: Close the inlet adjustable guide vane, open the inter-stage bleeding valve to 100% opening, open the exhaust air venting coarse adjustment valve to 50% opening, and close the exhaust air venting fine adjustment valve. Then, increase the speed to the rated speed.

[0108] Step five: During the speed increase process, the control system uses the "start-up and shut-down control line set" as the anti-surge control line. When the unit state exceeds the surge light control line LCL but does not reach the surge medium control line MCL, the PI controller of the control system is activated to adjust the exhaust air venting fine adjustment valve to reduce the unit state below the light control line LCL. When the unit state exceeds the surge medium control line MCL but does not reach the surge strength control line SCL, the exhaust air venting fine adjustment valve is continuously opened by 5% until the unit state is reduced below the light control line LCL. When the unit state exceeds the strength control line SCL but does not reach the surge line SL, the exhaust air venting coarse adjustment valve is opened by 10% and the exhaust air venting fine adjustment valve is opened by 5%. When the unit state further rises to the surge line SL, the exhaust air venting coarse adjustment valve is fully opened, the exhaust air venting fine adjustment valve is fully opened, and the speed increase is stopped for the operator to handle.

[0109] Step six: When the converted speed reaches the rated speed, close the inter-stage bleeding valve, and the unit reaches the empty load operation state. The control system switches to use the "continuous operation control line set" as the anti-surge control line.

[0110] Step seven: Open the exhaust air supply valve while closing the exhaust air venting coarse adjustment valve until the exhaust air venting coarse adjustment valve is fully closed and the exhaust air supply valve is fully opened. Then, adjust the inlet adjustable guide vane opening to 80% opening, and the unit reaches the full load operation state to meet the downstream process requirements.

[0111] Step eight: Continuous operation at the rated speed. When the downstream process requirements change, make corresponding adjustments:

[0112] ① When the downstream gas supply pressure demand increases, close the exhaust air supply valve to an appropriate opening, and adjust to the target exhaust air pressure to increase the exhaust air pressure of the compressor train.

[0113] ② When the downstream gas supply pressure demand decreases, open the exhaust air bleed fine control valve to an appropriate opening, and adjust to the target exhaust air pressure to decrease the exhaust air pressure of the compressor train.

[0114] ③ When the downstream gas supply flow demand increases, increase the inlet adjustable guide vane opening, and adjust to the target exhaust air flow.

[0115] ④ When the downstream gas supply flow demand decreases, decrease the inlet adjustable guide vane opening, and adjust to the target exhaust air flow.

[0116] Step Nine: During continuous operation, the control system uses the "continuous operation control line set" as the anti-surge control line. When the train state exceeds the mild surge control line LCL but does not reach the moderate surge control line MCL, the PI controller of the control system is activated to target the mild control line LCL to adjust the exhaust air bleed fine control valve to reduce the train state below the mild control line LCL. When the train state exceeds the moderate surge control line MCL but does not reach the intensity control line SCL, the exhaust air bleed fine control valve is continuously opened by 5% adjustment steps until the train state is reduced below the mild control line LCL. When the train state exceeds the intensity control line SCL but does not reach the surge line SL, the exhaust air bleed coarse control valve is opened by 15% and the exhaust air bleed fine control valve is opened by 5%. When the train state further rises to the surge line SL, the exhaust air bleed coarse control valve is opened to 50% opening, the exhaust air bleed fine control valve is fully opened, and the inter-stage bleed valve is fully opened. The operator handles it manually.

[0117] Step Ten: Before speed reduction shutdown, close the exhaust air supply valve while opening the exhaust air bleed coarse control valve until the exhaust air bleed coarse control valve is opened to 50% opening, the exhaust air supply valve is fully closed, and the connection between the compressor train and the downstream process is cut off.

[0118] Step Eleven: Close the inlet adjustable guide vane, open the inter-stage bleed valve to 100% opening, and close the exhaust air bleed fine control valve. Then, the speed reduction shutdown is performed. The control system switches to use the "start-stop control line set" as the anti-surge control line.

[0119] Step twelve: During the speed reduction process, the control system uses the "start-stop control line group" as the anti-surge control line. When the unit state exceeds the mild surge control line LCL but does not reach the moderate surge control line MCL, the PI controller of the control system is activated to target the mild control line LCL, and the exhaust air venting fine adjustment valve is adjusted to reduce the unit state below the mild control line LCL. When the unit state exceeds the moderate surge control line MCL but does not reach the intensity control line SCL, the exhaust air venting fine adjustment valve is continuously opened by 5% until the unit state is reduced below the mild control line LCL. When the unit state exceeds the intensity control line SCL but does not reach the surge line SL, the exhaust air venting coarse adjustment valve is opened by 10% and the exhaust air venting fine adjustment valve is opened by 5%. When the unit state further rises to the surge line SL, the exhaust air venting coarse adjustment valve is fully opened and the exhaust air venting fine adjustment valve is fully opened, and the speed reduction continues until the operator handles it.

[0120] Step thirteen: After the unit completes the speed reduction and low-speed turning, all air pipeline valves are closed.

[0121] Compared with the prior art, the technical scheme has the following beneficial effects:

[0122] 1. Independent start and stop. Through the switching of the exhaust air venting pipeline and the exhaust air supply pipeline, the independent start and stop of the unit is ensured, and compared with the prior art, the start and stop process of the compressor can be more accurately controlled, avoiding the occurrence of phenomena such as stall or surge.

[0123] 2. Inter-stage anti-surge. The inter-stage venting optimizes the inter-stage matching of the unit during the start and stop process, and compared with the prior art, the stable operation of the compressor during the start and stop process can be better ensured.

[0124] 3. Exhaust air anti-surge. Through the combined application of the exhaust air venting coarse adjustment valve and the fine adjustment valve, compared with the prior art, the compressor unit can be more flexibly controlled away from the surge boundary.

[0125] 4. Control line classification. By classifying the anti-surge control lines according to the operating state of the unit, they are divided into two groups, and compared with the prior art, the state change of the compressor can be more accurately controlled, and the anti-surge strategy is more targeted.

[0126] In summary, the technical scheme has the advantages of more accurate and stable control of the operating state of the compressor compared with the prior art, and can better ensure the efficiency and stability of the compressor unit.

[0127] For example, Figure 5As shown, the application also provides an axial compressor control device with inter-stage bleed, the compressor comprising an inter-stage bleed valve and several other valves and corresponding ventilation pipelines, and the compressor is provided with a control line group by preset surge boundary, the control line group comprising a start-stop control line group and a continuous operation control line group; the device comprises:

[0128] A parameter state determination unit 501 is configured to determine the operating parameters and operating states of the compressor, wherein the operating parameters comprise compressor inlet total pressure, compressor outlet total pressure, physical rotation speed, compressor inlet total temperature and inlet guide vane opening degree, and the operating states comprise a start-up process, continuous operation and a shutdown process;

[0129] A rotation speed and pressure ratio determination unit 502 is configured to determine the pressure ratio of the compressor by the compressor inlet total pressure and the compressor outlet total pressure in the operating parameters, determine the equivalent rotation speed according to the physical rotation speed and the inlet total temperature of the compressor, and adjust the opening and closing state of the inter-stage bleed valve according to the equivalent rotation speed and the operating state;

[0130] A control line group matching unit 503 is configured to determine the currently matched control line group of the compressor by the operating parameters, the operating state and the opening and closing state of the inter-stage bleed valve;

[0131] A first adjustment unit 504A is configured to adjust several other valves of the compressor according to the equivalent rotation speed, the pressure ratio and the start-stop control line group when the compressor matches the start-stop control line group;

[0132] A second adjustment unit 504B is configured to adjust several other valves of the compressor according to the inlet guide vane opening degree, the pressure ratio and the continuous operation control line group when the compressor matches the continuous operation control line group.

[0133] In another embodiment, the surge boundary comprises a first surge boundary and a second surge boundary, wherein the first surge boundary is used to represent the maximum pressure ratio of the compressor at different equivalent rotation speeds, and the second surge boundary is used to represent the maximum pressure ratio of the compressor at different inlet guide vane opening degrees at rated rotation speed; the compressor is provided with a surge margin of each control line in the control line group in advance;

[0134] The control line group provided by the preset surge boundary and the surge margin comprises:

[0135] A first surge line SL is determined according to the preset first surge boundary, wherein the first surge boundary is used to represent the maximum pressure ratio of the compressor at different equivalent rotation speeds;

[0136] Other first surge control lines are determined based on the reserved first surge margin and the first surge line SL, wherein the other first surge control lines include the first mild surge control line LCL, the first moderate surge control line MCL, and the first surge intensity control line SCL;

[0137] The start-stop control line group is formed by the first surge line SL and the other first surge control lines.

[0138] The second surge line SL is determined according to the preset second surge boundary, wherein the second surge boundary is used to characterize the maximum pressure ratio of the compressor at different inlet guide vane openings at the rated speed;

[0139] Other second surge control lines are determined based on the reserved second surge margin and the second surge line SL, wherein the other second surge control lines include the second mild surge control line LCL, the second moderate surge control line MCL, and the second surge intensity control line SCL;

[0140] The second surge line SL and the other second surge control lines together form the continuous operation control line group.

[0141] In another embodiment, the plurality of other valves include an exhaust air supply valve and an exhaust vent valve, and the device further includes:

[0142] Other valve adjustment units 505 are used to detect the gas supply demand of the downstream process when the compressor is running continuously at the rated speed, and adjust the exhaust air supply valve, exhaust vent valve and inlet adjustable guide vane opening according to the gas supply demand, wherein the gas supply demand includes gas supply pressure demand and gas supply flow demand.

[0143] In another embodiment, determining other first surge control lines based on the reserved first surge margin and the first surge line SL includes:

[0144] pass Calculate the control line voltage ratio of other first surge control lines at different reduced speeds, and determine the corresponding other first surge control lines based on the control line voltage ratio and the reduced speed. The pressure ratio of the first surge line SL at the reduced rotational speed, the SM is the control line voltage ratio of other first surge control lines at the reduced rotational speed, and SM is the surge margin.

[0145] In another embodiment, the plurality of other valves includes an exhaust air supply valve, and the device further includes:

[0146] An independent start-stop unit 506 is configured to control the exhaust air supply valve and the exhaust air vent valve to cut off the connection between the compressor and the downstream process before the compressor starts or stops.

[0147] The above embodiment of the present application provides a control method of an axial flow compressor provided with inter-stage bleeding, and a control device of an axial flow compressor provided with inter-stage bleeding based on the method. Through the method and device, the problem that the existing control method of an axial flow compressor lacks operation and control of valves related to inter-stage bleeding and is not applicable to this type of compressor unit is solved.

[0148] The embodiment also discloses a computer device, which comprises a processor and a memory, and the memory stores at least one instruction, which is loaded and executed by the processor to implement the control method of the axial flow compressor provided with inter-stage bleeding.

[0149] In addition, in the above embodiment of the control device of the axial flow compressor provided with inter-stage bleeding, the logical division of each program module is only illustrative, and in actual application, the above functions can be completed by different program modules according to needs, for example, for the configuration requirements of corresponding hardware or the convenience of software implementation, so as to divide the internal structure of the control device of the axial flow compressor provided with inter-stage bleeding into different program modules to complete all or part of the above functions.

[0150] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A control method for an axial flow compressor with interstage venting, characterized in that, The compressor includes an interstage vent valve and several other valves and corresponding ventilation piping. The compressor is configured with a control line group based on a preset surge boundary. This control line group includes a start / stop control line group and a continuous operation control line group. The surge boundary includes a first surge boundary and a second surge boundary. The first surge boundary characterizes the maximum pressure ratio of the compressor at different equivalent speeds, and the second surge boundary characterizes the maximum pressure ratio of the compressor at different inlet guide vane openings at rated speeds. The compressor pre-sets the surge margin for each control line in the control line group. Specifically, configuring the control line group based on the preset surge boundary includes: A first surge line SL is determined based on a preset first surge boundary. Other first surge control lines are determined based on the surge margin and the first surge line SL. The other first surge control lines include a first mild surge control line LCL, a first moderate surge control line MCL, and a first surge intensity control line SCL. The start-stop control line group is formed by the first surge line SL and the other first surge control lines. A second surge line SL is determined based on a preset second surge boundary. Other second surge control lines are determined based on the surge margin and the second surge line SL. The other second surge control lines include a second mild surge control line LCL, a second moderate surge control line MCL, and a second surge intensity control line SCL. The second surge line SL and the other second surge control lines together form the continuous operation control line group; The method includes: The operating parameters and operating status of the compressor are determined. The operating parameters include the compressor inlet total pressure, compressor outlet total pressure, physical speed, compressor inlet total temperature, and inlet guide vane opening. The operating status includes the start-up process, continuous operation, and shutdown process. The compressor pressure ratio is determined by the compressor inlet total pressure and compressor outlet total pressure in the operating parameters. The equivalent speed is determined by the compressor physical speed and inlet total temperature. The opening and closing state of the interstage vent valve is adjusted by the equivalent speed and the operating state. The control line group currently matched to the compressor is determined by the operating parameters, operating status, and on / off status of the interstage vent valve. When the compressor is matched with the start-stop control line group, several other valves of the compressor are adjusted according to the equivalent speed, pressure ratio, and the start-stop control line group; When the compressor is matched with a continuous operation control line, several other valves of the compressor are adjusted according to the inlet guide vane opening, pressure ratio, and the continuous operation control line.

2. The method according to claim 1, characterized in that, The other valves include an exhaust air supply valve and an exhaust vent valve, and the method further includes: When the compressor is running continuously at its rated speed, it detects the gas supply demand of the downstream process and adjusts the exhaust air supply valve, exhaust vent valve and inlet adjustable guide vane opening according to the gas supply demand. The gas supply demand includes gas supply pressure demand and gas supply flow demand.

3. The method according to claim 1, characterized in that, The step of determining other first surge control lines based on the surge margin and the first surge line SL includes: pass Calculate the control line voltage ratio of other first surge control lines at different reduced speeds, and determine the corresponding other first surge control lines based on the control line voltage ratio and the reduced speed. The pressure ratio of the first surge line SL at the reduced rotational speed, the SM is the control line voltage ratio of other first surge control lines at the reduced rotational speed, and SM is the surge margin.

4. The method according to claim 1, characterized in that, The other valves include an exhaust air supply valve and an exhaust vent valve, and the method further includes: Before the compressor is started or stopped, the exhaust air supply valve and the exhaust vent valve are controlled to disconnect the compressor from the downstream process flow.

5. A control device for an axial flow compressor equipped with interstage venting, characterized in that, The compressor includes an interstage vent valve and several other valves and corresponding ventilation piping. The compressor is configured with a control line group based on a preset surge boundary. This control line group includes a start / stop control line group and a continuous operation control line group. The surge boundary includes a first surge boundary and a second surge boundary. The first surge boundary characterizes the maximum pressure ratio of the compressor at different equivalent speeds, and the second surge boundary characterizes the maximum pressure ratio of the compressor at different inlet guide vane openings at rated speeds. The compressor pre-sets the surge margin for each control line in the control line group. Specifically, configuring the control line group based on the preset surge boundary includes: A first surge line SL is determined based on a preset first surge boundary. Other first surge control lines are determined based on the surge margin and the first surge line SL. The other first surge control lines include a first mild surge control line LCL, a first moderate surge control line MCL, and a first surge intensity control line SCL. The start-stop control line group is formed by the first surge line SL and the other first surge control lines. A second surge line SL is determined based on a preset second surge boundary. Other second surge control lines are determined based on the surge margin and the second surge line SL. The other second surge control lines include a second mild surge control line LCL, a second moderate surge control line MCL, and a second surge intensity control line SCL. The second surge line SL and the other second surge control lines together form the continuous operation control line group; The device includes: The parameter status determination unit is used to determine the operating parameters and operating status of the compressor. The operating parameters include the compressor inlet total pressure, compressor outlet total pressure, physical speed, compressor inlet total temperature, and inlet guide vane opening. The operating status includes the start-up process, continuous operation, and shutdown process. The speed and pressure ratio determination unit is used to determine the pressure ratio of the compressor through the compressor inlet total pressure and compressor outlet total pressure in the operating parameters, determine the equivalent speed according to the physical speed and inlet total temperature of the compressor, and adjust the opening and closing state of the interstage vent valve through the equivalent speed and the operating state; The control line matching unit is used to determine the control line currently matched to the compressor based on the operating parameters, operating status and the on / off status of the interstage vent valve; The first adjustment unit is used to adjust several other valves of the compressor according to the equivalent speed, pressure ratio and the start-stop control line group when the compressor is matched with the start-stop control line group; The second adjustment unit is used to adjust several other valves of the compressor according to the inlet guide vane opening, pressure ratio, and the continuous operation control line group when the compressor is matched with the continuous operation control line group.

6. The apparatus according to claim 5, characterized in that, The other valves include an exhaust air supply valve and an exhaust vent valve, and the device further includes: Other valve adjustment units are used to detect the gas supply demand of the downstream process when the compressor is running continuously at the rated speed, and adjust the exhaust air supply valve, exhaust vent valve and inlet adjustable guide vane opening according to the gas supply demand, wherein the gas supply demand includes gas supply pressure demand and gas supply flow demand.

7. The apparatus according to claim 5, characterized in that, The step of determining other first surge control lines based on the surge margin and the first surge line SL includes: pass Calculate the control line voltage ratio of other first surge control lines at different reduced speeds, and determine the corresponding other first surge control lines based on the control line voltage ratio and the reduced speed. The pressure ratio of the first surge line SL at the reduced rotational speed, the SM is the control line voltage ratio of other first surge control lines at the reduced rotational speed, and SM is the surge margin.

8. The apparatus according to claim 5, characterized in that, The other valves include an exhaust / air supply valve, and the device further includes: An independent start / stop unit is used to control the exhaust air supply valve and the exhaust vent valve to disconnect the compressor from the downstream process flow before the compressor starts or stops.

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