Method and device for controlling axial flow compressor with interstage deflation

Abstract

The invention is suitable for the field of anti-surge control of compressors, and provides a control method and device for an axial flow compressor with an interstage deflation function. In the embodiment of the invention, for the axial flow compressor with interstage deflation, the start-stop control line group and the continuous operation control line group are set in advance according to the surge boundary and the surge margin of the compressor, and when the compressor operates, the start-stop control line group and the continuous operation control line group are set according to the operation parameters of the compressor; a matched control line group is determined according to the running state and the on-off state of the interstage deflation valve; and then according to the pressure ratio, the folded rotating speed and the opening degree of the inlet guide vane of the compressor, all valves of the compressor, such as an exhaust air supply valve, an exhaust emptying valve and an interstage deflation valve, are adjusted, so that the problems of unstable operation of the compressor, possible stall or surge and the like are avoided.

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 bleed air. Background Art

[0002] In modern industrial production, compressors are an important equipment, widely used in various occasions that require compressed gas, such as petroleum, chemical, metallurgy, electric power, machinery manufacturing and other industries. Among them, axial flow compressors are widely used in large-scale industrial production due to their simple structure, high efficiency, large flow rate and other advantages. However, the operating characteristics of axial flow compressors are complex, and their operating status is affected by many factors, such as intake temperature, downstream process gas demand, adjustable guide vane / stator opening, etc. Therefore, how to effectively control the operating status of axial flow compressors to ensure their 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 the start-up and shutdown process by making all the stator blades adjustable. During continuous operation, the axial flow compressor controls the state of the compressor during operation through the anti-surge valve and the vent valve to prevent the unit from surging.

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

[0005] First, the parameters monitored by the existing control strategy for the unit are not applicable to the high-pressure ratio axial flow compressor unit with interstage bleed. The unit performance parameters monitored by the existing control strategy are the throat differential pressure and the exhaust pressure: the throat differential pressure can reflect the intake flow of the compressor, but in the high-pressure ratio compressor unit with interstage bleed, due to the existence of interstage bleed, the compressor working state corresponding to the intake flow is not unique. The exhaust pressure can reflect the pressure ratio of the compressor, but in the high-pressure ratio large margin axial flow compressor unit, due to the change of the intake pressure loss, the compressor pressure ratio corresponding to the exhaust pressure is not unique.

[0006] Secondly, the existing control strategy has a single description of the state of the compressor unit. It is unable to cope with the control line changes of the high pressure ratio large margin axial flow compressor unit under the state of fixed speed and variable adjustable inlet guide vane opening; it is unable to describe the control line changes of the high pressure ratio large margin axial flow compressor unit before and after the interstage bleed valve is opened during the start and stop process.

[0007] Finally, for high-pressure ratio and large-margin axial-flow compressor units equipped with interstage bleed, the existing control strategy lacks the operation and control of the interstage bleed-related valves and cannot cope with the start-stop and abnormal control of such compressor units. Summary of the invention

[0008] In view of this, the present application provides an axial flow compressor control method and device provided with inter-stage bleed, so as to solve the problem that the existing axial flow compressor control method lacks operation and control of the inter-stage bleed related valves and is not suitable for this type of compressor unit.

[0009] In a first aspect, the present application provides a control method for an axial flow compressor provided with interstage bleed, wherein the compressor comprises an interstage bleed valve and a plurality of other valves and corresponding ventilation pipelines, and the compressor sets a control line group through a preset surge boundary, wherein the control line group comprises a start-stop control line group and a continuous operation control line group; the method comprises: Determine the operating parameters and operating state of the compressor, wherein the operating parameters include the compressor inlet total pressure, the compressor outlet total pressure, the physical speed, the compressor inlet total temperature and the inlet guide vane opening, and the operating state includes the startup process, continuous operation and shutdown process; The pressure ratio of the compressor is determined by the compressor inlet total pressure and the compressor outlet total pressure in the operating parameters, the reduced speed is determined according to the physical speed and the inlet total temperature of the compressor, and the switch state of the interstage air release valve is adjusted according to the reduced speed and the operating state; Determine the control line group currently matched by the compressor through the operating parameters, the operating state and the switch state of the inter-stage air bleed valve; When the compressor matches the start-stop control line group, several other valves of the compressor are adjusted according to the reduced speed, pressure ratio and the start-stop control line group; When the compressor matches the continuous operation control line group, several other valves of the compressor are adjusted according to the inlet guide vane opening, the pressure ratio and the continuous operation control line group.

[0010] Optionally, the surge boundary includes a first surge boundary and a second surge boundary, wherein the first surge boundary is used to characterize the maximum value of the pressure ratio of the compressor at different converted speeds, and the second surge boundary is used to characterize the maximum value of the pressure ratio of the compressor at different inlet guide vane openings at rated speed; the compressor pre-sets a surge margin for each control line in the control line group; The control line group is set by preset surge boundary and surge margin, including: Determining a first surge line SL according to a preset first surge boundary, wherein the first surge boundary is used to characterize a maximum pressure ratio of the compressor at different reduced speeds; Determining other first surge control lines according to the reserved first surge margin and the first surge line SL, wherein 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 line groups; Determining a second surge line SL according to a 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 a rated speed; Determining other second surge control lines according to the reserved second surge margin and the second surge line SL, wherein 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 line groups form the continuous operation control line group.

[0011] Optionally, the plurality of other valves include an exhaust air supply valve and an exhaust vent valve, and the method further includes: When the compressor runs continuously at the rated speed, the air supply demand of the downstream process is detected, and the exhaust air supply valve, the exhaust vent valve and the inlet adjustable guide vane opening are adjusted according to the air supply demand, wherein the air supply demand includes the air supply pressure demand and the air supply flow demand.

[0012] Optionally, the determining other first surge control lines according to the reserved first surge margin and the first surge line SL includes: pass Calculate the control line pressure ratio of other first surge control lines under different converted speeds, and determine the corresponding other first surge control lines according to the control line pressure ratio and the converted speed, wherein: is the pressure ratio of the first surge line SL at the reduced speed, is the control line pressure ratio of the other first surge control line at the converted speed, and SM is the surge margin.

[0013] Optionally, the plurality of other valves include an exhaust air supply 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 cut off the connection between the compressor and the downstream process flow.

[0014] A second aspect of the present application provides an axial flow compressor control device provided with interstage bleed, the compressor comprising an interstage bleed valve and a plurality of other valves and corresponding ventilation pipelines, and the compressor sets a control line group through a preset surge boundary, the control line group comprising a start-stop control line group and a continuous operation control line group; the device comprises: a parameter state determination unit, configured to determine the operating parameters and operating state of the compressor, wherein the operating parameters include the compressor inlet total pressure, the compressor outlet total pressure, the physical speed, the compressor inlet total temperature and the inlet guide vane opening, and the operating state includes the startup process, continuous operation and shutdown process; a speed and pressure ratio determination unit, configured to determine the pressure ratio of the compressor according to the compressor inlet total pressure and the compressor outlet total pressure in the operating parameters, determine the reduced speed according to the physical speed and the inlet total temperature of the compressor, and adjust the switch state of the interstage air release valve according to the reduced speed and the operating state; A control line group matching unit, used to determine the control line group currently matched by the compressor according to the operating parameters, operating status and the switch status of the inter-stage air release valve; A first adjustment unit, used for adjusting a plurality of other valves of the compressor according to the reduced speed, the pressure ratio and the start-stop control line group when the compressor matches 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, the pressure ratio and the continuous operation control line group when the compressor matches the continuous operation control line group.

[0015] Optionally, the surge boundary includes a first surge boundary and a second surge boundary, wherein the first surge boundary is used to characterize the maximum value of the pressure ratio of the compressor at different converted speeds, and the second surge boundary is used to characterize the maximum value of the pressure ratio of the compressor at different inlet guide vane openings at rated speed; the compressor pre-sets a surge margin for each control line in the control line group; The control line group is set by preset surge boundary and surge margin, including: Determining a first surge line SL according to a preset first surge boundary, wherein the first surge boundary is used to characterize a maximum pressure ratio of the compressor at different reduced speeds; Determining other first surge control lines according to the reserved first surge margin and the first surge line SL, wherein 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 line groups; Determining a second surge line SL according to a 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 a rated speed; Determining other second surge control lines according to the reserved second surge margin and the second surge line SL, wherein 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 line groups form the continuous operation control line group.

[0016] Optionally, the plurality of 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 runs continuously at the rated speed, and adjust the exhaust air supply valve, the exhaust vent valve and the inlet adjustable guide vane opening according to the gas supply demand, wherein the gas supply demand includes the gas supply pressure demand and the gas supply flow demand.

[0017] Optionally, the determining other first surge control lines according to the reserved first surge margin and the first surge line SL includes: pass Calculate the control line pressure ratio of other first surge control lines under different converted speeds, and determine the corresponding other first surge control lines according to the control line pressure ratio and the converted speed, wherein: is the pressure ratio of the first surge line SL at the reduced speed, is the control line pressure ratio of the other first surge control line at the converted speed, and SM is the surge margin.

[0018] Optionally, the plurality of other valves include an exhaust air supply valve, and the device further includes: The independent start-stop unit is used to control the exhaust air supply valve and the exhaust vent valve to cut off the connection between the compressor and the downstream process flow before the compressor is started or stopped.

[0019] In the embodiments provided in the present application, for an axial flow compressor provided with interstage bleed, 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, a matching control line group is first determined according to the operating parameters, operating status and switching status of the interstage bleed valve of the compressor; then, the various valves of the compressor, such as the exhaust air supply valve, the exhaust vent valve and the interstage bleed valve, are adjusted according to the pressure ratio, converted speed and inlet guide vane opening of the compressor, so as to avoid unstable operation of the compressor and possible problems such as stall or surge. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A flow chart of the method provided in the embodiment of the present application; Figure 2 This is a schematic diagram of the start-stop control line group; Figure 3 It is a schematic diagram of the continuous operation control line group; Figure 4 This is a schematic diagram of the anti-asthma control strategy; Figure 5 A structural diagram of a device provided in an embodiment of the present application; DETAILED DESCRIPTION

[0021] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0022] The terms used in this application are only used to describe specific embodiments and are not intended to limit the scope of this application. In this application and the appended claims, the singular forms of "a", "the" and "the" used are also intended to include plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein refers to any or all possible combinations of one or more associated listed items.

[0023] It should be understood that although the terms first, second, third, etc. may be used in the present application to describe various information, these information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining".

[0024] The present application provides a control method and device for an axial flow compressor provided with interstage bleed, so as to solve the problem that the existing control method for axial flow compressor lacks operation and control of valves related to interstage bleed and is not suitable for this type of compressor unit.

[0025] The technical solution of the present application is described in detail with specific embodiments below. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments.

[0026] like Figure 1As shown, it is a flow chart of a control method for an axial flow compressor with interstage bleed provided in the present application, the compressor includes an interstage bleed valve and several other valves and corresponding ventilation pipelines, and the compressor sets a control line group through a preset surge boundary, and the control line group includes a start-stop control line group and a continuous operation control line group.

[0027] In this embodiment, other valves include exhaust air supply valves, exhaust vent coarse adjustment valves, exhaust vent fine adjustment valves, and the like. The corresponding ventilation pipelines include exhaust vent pipelines, exhaust air supply pipelines, and interstage bleed pipelines. The surge boundary includes the surge boundary during startup and shutdown and the surge boundary at the rated speed. The surge boundary during startup and shutdown is the maximum pressure ratio of the compressor at each converted speed, so the horizontal coordinate of each control line in the startup and shutdown control line group is the converted speed, and the vertical coordinate is the pressure ratio of the compressor. The surge boundary at the rated speed is the maximum pressure ratio at different inlet guide vane openings, so the horizontal coordinate of each control line in the continuous operation control line group is the inlet guide vane opening, and the vertical coordinate is the pressure ratio of the compressor.

[0028] In the control line group, the surge line SL is the surge boundary, and other control lines are offset downward based on the surge boundary, that is, the corresponding pressure ratio is reduced at the same reduced speed. For example, a 5% offset is used as an emergency control line, 20% is a mild control line, and so on.

[0029] In another embodiment, the surge boundary includes a first surge boundary and a second surge boundary, wherein the first surge boundary is used to characterize the maximum value of the pressure ratio of the compressor at different converted speeds, and the second surge boundary is used to characterize the maximum value of the pressure ratio of the compressor at different inlet guide vane openings at the rated speed; the compressor pre-sets the surge margin of each control line in the control line group; The control line group is set by the preset surge boundary, comprising: Determining a first surge line SL according to a preset first surge boundary, and determining other first surge control lines according to the surge margin and the first surge line SL, wherein 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 line groups; Determining a second surge line SL according to a preset second surge boundary, and determining other second surge control lines according to the surge margin and the second surge line SL, wherein 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 line groups form the continuous operation control line group.

[0030] In this embodiment, the corresponding surge margin is pre-set for each control line, such as the surge light control line LCL is 15%, the surge medium control line MCL is 10%, and the surge intensity control line SCL is 5%. Then, through the formula Calculate the pressure ratio of each control line under the same conditions to determine the corresponding control line. is the pressure ratio of the surge line, is the pressure ratio of the control line, and SM is the surge margin.

[0031] Exemplarily, for the control line in the start-stop control line group, is the pressure ratio of the first surge line SL at different reduced speeds. The pressure ratio corresponding to the reduced speed can be calculated by the above formula, so that the control line under each surge margin can be determined according to the reduced speed and pressure ratio. The schematic diagram of the specific start-stop control line group is as follows: Figure 2 shown.

[0032] Similarly, for the control line in the continuous operation control line group, the speed of the compressor is fixed at the rated speed, so the second surge boundary is the maximum pressure ratio of the compressor at different inlet guide vane openings at the rated speed. is the pressure ratio of the second surge line SL under different inlet guide vane openings. The pressure ratio corresponding to the inlet guide vane opening can be calculated by the above formula, so that the control line under each surge margin can be determined according to the inlet guide vane opening and the pressure ratio. The schematic diagram of the specific continuous operation control line group is as follows Figure 3 shown.

[0033] After the control line group is determined, the steps of the above-mentioned axial flow compressor control method with interstage bleed are as follows: Step S101, determining the operating parameters and operating status of the compressor, wherein the operating parameters include the compressor inlet total pressure, the compressor outlet total pressure, the physical speed, the compressor inlet total temperature and the inlet guide vane opening, and the operating status includes the startup process, continuous operation and shutdown process.

[0034] In this embodiment, various operating parameters of the compressor can be determined by various sensors or other detection devices. For the operating state, it can be determined by the instructions received by the compressor (such as the start-up and shutdown instructions), the reduced speed and the preset rated speed. The reduced speed is determined by the physical speed and the total temperature of the compressor inlet. When the reduced speed of the compressor does not reach the rated speed, it is determined that the compressor is in the startup process or the shutdown process. When the reduced speed reaches the rated speed, it is determined that it is in a continuous operation state.

[0035] Step S102, determining the pressure ratio of the compressor through the compressor inlet total pressure and the compressor outlet total pressure in the operating parameters, determining the reduced speed according to the physical speed and the inlet total temperature of the compressor, and adjusting the switching state of the interstage air release valve according to the reduced speed and the operating state.

[0036] In this embodiment, the formula Determine the pressure ratio of the compressor. In this formula, is the total pressure at the compressor inlet, is the total pressure at the compressor outlet.

[0037] By formula Determine the reduced speed of the compressor, where n is the physical speed in r / min; is the total temperature at the compressor inlet, in K. When the compressor is in the startup state and the converted speed reaches the preset value, such as 90% of the rated speed, the interstage bleed valve is closed, and the speed is increased to the rated speed until the unit reaches the no-load working state. Then, by simultaneously controlling the exhaust vent coarse adjustment valve and the exhaust air supply valve, the flow distribution of the exhaust vent pipeline and the exhaust air supply pipeline is gradually adjusted to pass the high-pressure exhaust of the compressor unit to the downstream process. Then, the exhaust flow of the compressor is controlled by changing the opening of the inlet adjustable guide vane. At the same time, the exhaust pressure of the compressor unit is increased by reducing the flow capacity of the exhaust air supply pipeline or the flow resistance of the downstream process flow until the rated speed of the unit is reached.

[0038] Step S103, determining the control line group currently matched with the compressor according to the operating parameters, the operating state and the switch state of the inter-stage air bleed valve.

[0039] In this embodiment, the scenario of determining the control line group currently matched by the compressor is as follows: 1. Match the start and stop control line group: During the unit startup process, that is, when the operating state is the startup process and the interstage air release valve is in the open state, the compressor unit matches the startup and shutdown control line group as the anti-surge control line; During the shutdown process of the unit, that is, when the operating state is the shutdown process and the switch state of the interstage air bleed valve is open, the compressor unit matches the start-up shutdown control line group as the anti-surge control line.

[0040] 2. Matching continuous operation control line group: During the unit startup process, when the interstage air bleed valve is in the closed state, the compressor unit matches the continuous operation control line group as the anti-surge control line; During the unit shutdown process, when the interstage air bleed valve is in the closed state, the compressor unit matches the continuous operation control line group as the anti-surge control line; During the continuous operation of the unit at rated speed, the compressor unit matches the continuous operation control line group as the anti-surge control line.

[0041] When the compressor matches the start-stop control line group, step S104A is executed; when the compressor matches the continuous operation control line group, step S104B is executed.

[0042] Step S104A, when the compressor matches the start-stop control line group, several other valves of the compressor are adjusted according to the converted speed, pressure ratio and the start-stop control line group.

[0043] In this embodiment, the control line reached by the compressor unit is determined and adjusted according to the reduced speed and pressure ratio of the compressor. When the unit state exceeds the surge mild control line LCL but does not reach the surge moderate control line MCL, the PI controller of the control system is activated, and the exhaust vent fine-adjusting valve is adjusted to reduce the unit state to below the mild control line LCL with the mild control line LCL as the target. When the unit state exceeds the surge moderate control line MCL but does not reach the surge intensity control line SCL, the exhaust vent fine-adjusting valve is continuously opened with an adjustment step of 5% until the unit state drops 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 vent coarse-adjusting valve is opened by 10%, and the exhaust vent fine-adjusting valve is opened by 5%. When the unit state further rises to the surge line SL, the exhaust vent coarse-adjusting valve is fully opened, the exhaust vent fine-adjusting valve is fully opened, and the speed increase is stopped or the speed reduction continues to wait for the operator to deal with.

[0044] Step S104B: when the compressor matches the continuous operation control line group, several other valves of the compressor are adjusted according to the inlet guide vane opening, the pressure ratio and the continuous operation control line group.

[0045] In this embodiment, when the unit state exceeds the surge mild control line LCL but does not reach the surge moderate control line MCL, the PI controller of the control system is activated, and the exhaust vent fine-adjusting valve is adjusted to reduce the unit state to below the mild control line LCL with the mild control line LCL as the target. When the unit state exceeds the surge moderate control line MCL but does not reach the surge intensity control line SCL, the exhaust vent fine-adjusting valve is continuously opened with an adjustment step of 5% until the unit state drops 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 vent coarse-adjusting valve is opened by 15%, and the exhaust vent fine-adjusting valve is opened by 5%. When the unit state further rises to the surge line SL, the exhaust vent coarse-adjusting valve is opened to 50% opening, the exhaust vent fine-adjusting valve is fully opened, and the inter-stage bleed valve is fully opened, waiting for manual disposal by the operator.

[0046] In another embodiment, the method further comprises: before the compressor is started or stopped, controlling the exhaust air supply valve and the exhaust vent valve to cut off the connection between the compressor and the downstream process flow.

[0047] In this embodiment, before starting the speed increase, the connection between the compressor unit and the downstream process flow is cut off by closing the exhaust air supply valve, thereby ensuring independent startup of the unit.

[0048] Before shutting down and slowing down, the exhaust vent coarse adjustment valve and the exhaust air supply valve are controlled simultaneously to gradually adjust the flow distribution of the exhaust vent pipeline and the exhaust air supply pipeline. While maintaining the exhaust pressure of the compressor, the exhaust air supply valve is closed to cut off the connection between the compressor unit and the downstream process flow, thereby ensuring independent shutdown of the unit.

[0049] This embodiment switches the exhaust vent pipeline and the exhaust air supply pipeline by controlling the exhaust air supply valve and the exhaust vent valve, thereby ensuring independent start and stop of the unit. Compared with the prior art, it can more accurately control the start and stop process of the compressor, avoiding the occurrence of stall or surge and the like.

[0050] So far, completed Figure 1 The process shown.

[0051] In an embodiment of the present application, for an axial flow compressor provided with interstage bleed, 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, a matching control line group is first determined according to the operating parameters, operating status and switching status of the interstage bleed valve of the compressor; then, according to the pressure ratio, converted speed and inlet guide vane opening of the compressor, various valves of the compressor, such as the exhaust air supply valve, the exhaust vent valve and the interstage bleed valve are adjusted, so as to avoid unstable operation of the compressor and possible problems such as stall or surge.

[0052] The above method is described below by a specific embodiment. The schematic diagram of the anti-surge control strategy in this embodiment is shown in FIG. Figure 4 As shown, the specific implementation steps are as follows: Step 1: Based on strategic requirements, set up the required air pipelines and corresponding valves outside the axial compressor unit: ① Interstage bleed pipe and interstage bleed valve: divided into three lines: low pressure, medium pressure and high pressure, with the total pipe diameter ranging from DN150 to DN250. The valve should be an adjustable valve.

[0053] ② Exhaust vent pipeline and exhaust vent rough adjustment valve, exhaust vent fine adjustment valve: The diameter of the exhaust vent rough adjustment valve is DN400 to DN500, and the diameter of the exhaust vent fine adjustment valve is DN200 to DN250. Both the exhaust vent rough adjustment valve and the exhaust vent fine adjustment valve are adjustable valves.

[0054] ③ Exhaust air supply pipeline and exhaust air supply valve: pipe diameter DN600 to DN1000. The exhaust air supply valve is an adjustable valve.

[0055] Step 2: Set up two groups of control lines in the control system: "start and stop control line group" and "continuous operation control line group".

[0056] "Start-stop control line group": The horizontal coordinate of the control line is the converted speed, and the vertical coordinate is the pressure ratio of the compressor. The surge line SL is the actual surge boundary of the unit during startup and shutdown. The surge intensity control line SCL reserves a 2% surge margin, the moderate surge control line MCL reserves a 5% surge margin, and the mild surge control line LCL reserves a 10% surge margin.

[0057] "Continuous operation control line group": The horizontal coordinate of the control line is the inlet guide vane opening, and the vertical coordinate is the compressor pressure ratio. The surge line SL is the actual surge boundary of the unit at rated speed, the surge intensity control line SCL reserves a 2% surge margin, the moderate surge control line MCL reserves a 5% surge margin, and the mild surge control line LCL reserves a 10% surge margin.

[0058] Step 3: Close the exhaust air supply valve to disconnect the compressor unit from the downstream process flow.

[0059] Step 4: Close the inlet adjustable guide vane, open the interstage bleed valve to 100% opening, open the exhaust vent coarse adjustment valve to 50% opening, and close the exhaust vent fine adjustment valve. Then increase the speed to the rated speed.

[0060] Step 5: During the speed increase process, the control system uses the "start-stop control line group" as the anti-surge control line. When the unit status exceeds the surge mild control line LCL but does not reach the surge moderate control line MCL, the PI controller of the control system is activated, and the exhaust vent fine-adjusting valve is adjusted to reduce the unit status to below the mild control line LCL with the mild control line LCL as the target. When the unit status exceeds the surge moderate control line MCL but does not reach the surge intensity control line SCL, the exhaust vent fine-adjusting valve is continuously opened with an adjustment step of 5% until the unit status drops below the mild control line LCL. When the unit status exceeds the intensity control line SCL but does not reach the surge line SL, the exhaust vent coarse-adjusting valve is opened by 10%, and the exhaust vent fine-adjusting valve is opened by 5%. When the unit status further rises to the surge line SL, the exhaust vent coarse-adjusting valve is fully opened, the exhaust vent fine-adjusting valve is fully opened, and the speed increase is stopped for the operator to deal with.

[0061] Step 6: When the reduced speed reaches the rated speed, close the interstage bleed valve and the unit reaches the no-load operation state. The control system switches to use the "continuous operation control line group" as the anti-surge control line.

[0062] Step 7: Open the exhaust air supply valve and close the exhaust venting coarse adjustment valve at the same time, until the exhaust venting coarse adjustment valve is completely 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 full load operation to meet the downstream process requirements.

[0063] Step 8: Run continuously at rated speed. When downstream process requirements change, make corresponding adjustments: ① When the downstream gas supply pressure demand increases, close the exhaust air supply valve to an appropriate opening and adjust it based on the required exhaust pressure to increase the exhaust pressure of the compressor unit.

[0064] ② When the downstream gas supply pressure demand decreases, open the exhaust vent fine-adjusting valve to an appropriate opening, and adjust it based on the required exhaust pressure to reduce the exhaust pressure of the compressor unit.

[0065] ③ When the downstream air supply flow demand increases, increase the opening of the inlet adjustable guide vane and adjust it according to the required exhaust flow.

[0066] ④ When the downstream air supply flow demand decreases, reduce the opening of the inlet adjustable guide vane and adjust it based on the required exhaust flow.

[0067] Step 9: During continuous operation, the control system uses the "continuous operation control line group" as the anti-surge control line. When the unit status exceeds the surge mild control line LCL but does not reach the surge moderate control line MCL, the PI controller of the control system is activated, and the exhaust vent fine-adjusting valve is adjusted to reduce the unit status to below the mild control line LCL with the mild control line LCL as the target. When the unit status exceeds the surge moderate control line MCL but does not reach the surge intensity control line SCL, the exhaust vent fine-adjusting valve is continuously opened with a 5% adjustment step until the unit status drops below the mild control line LCL. When the unit status exceeds the intensity control line SCL but does not reach the surge line SL, the exhaust vent coarse-adjusting valve is opened by 15%, and the exhaust vent fine-adjusting valve is opened by 5%. When the unit status further rises to the surge line SL, the exhaust vent coarse-adjusting valve is opened to 50% opening, the exhaust vent fine-adjusting valve is fully opened, and the interstage vent valve is fully opened, waiting for manual disposal by the operator.

[0068] Step 10: Before slowing down and shutting down, close the exhaust air supply valve and open the exhaust vent coarse adjustment valve at the same time, until the exhaust vent coarse adjustment valve is opened to 50% opening, the exhaust air supply valve is completely closed, and the connection between the compressor unit and the downstream process flow is cut off.

[0069] Step 11: Close the inlet adjustable guide vane, open the interstage bleed valve to 100% opening, and close the exhaust vent fine adjustment valve. Then reduce the speed and shut down. The control system switches to use the "start-stop control line group" as the anti-surge control line.

[0070] Step 12: During the speed reduction process, the control system uses the "start-stop control line group" as the anti-surge control line. When the unit status exceeds the surge mild control line LCL but does not reach the surge moderate control line MCL, the PI controller of the control system is activated, and the exhaust vent fine-adjusting valve is adjusted to reduce the unit status to below the mild control line LCL with the mild control line LCL as the target. When the unit status exceeds the surge moderate control line MCL but does not reach the surge intensity control line SCL, the exhaust vent fine-adjusting valve is continuously opened with an adjustment step of 5% until the unit status drops below the mild control line LCL. When the unit status exceeds the intensity control line SCL but does not reach the surge line SL, the exhaust vent coarse-adjusting valve is opened by 10%, and the exhaust vent fine-adjusting valve is opened by 5%. When the unit status further rises to the surge line SL, the exhaust vent coarse-adjusting valve is fully opened, the exhaust vent fine-adjusting valve is fully opened, and the speed reduction continues to wait for the operator to deal with it.

[0071] Step 13: After the unit has completed deceleration and low-speed cranking, close all air pipeline valves.

[0072] Compared with the existing technology, the beneficial effects of this technical solution are as follows: 1. Independent start and stop. The switch between the exhaust venting pipeline and the exhaust air supply pipeline ensures the independent start and stop of the unit. Compared with the existing technology, the start and stop process of the compressor can be controlled more accurately, avoiding the occurrence of stall or surge.

[0073] 2. Interstage anti-surge. The interstage matching of the unit during startup and shutdown is optimized through interstage bleed, which can better ensure the stable operation of the compressor during startup and shutdown compared with the existing technology.

[0074] 3. Exhaust anti-surge: Through the combined application of exhaust venting coarse adjustment valve and fine adjustment valve, the compressor unit can be controlled more flexibly to stay away from the surge boundary compared with the existing technology.

[0075] 4. Control line classification. By classifying the anti-surge control lines according to the operating status of the unit into two groups, the state change of the compressor can be controlled more accurately compared with the existing technology, and the anti-surge strategy is more targeted.

[0076] In summary, compared with the prior art, the present technical solution has the advantage of more accurately and stably controlling the operating state of the compressor, and can better ensure the high efficiency and stability of the compressor unit.

[0077] like Figure 5 As shown, the present application also provides an axial flow compressor control device provided with interstage bleed, the compressor comprises an interstage bleed valve and several other valves and corresponding ventilation pipelines, and the compressor sets a control line group through a preset surge boundary, the control line group comprises a start-stop control line group and a continuous operation control line group; the device comprises: A parameter state determination unit 501 is used to determine the operating parameters and operating state of the compressor, wherein the operating parameters include the compressor inlet total pressure, the compressor outlet total pressure, the physical speed, the compressor inlet total temperature and the inlet guide vane opening, and the operating state includes the startup process, continuous operation and shutdown process; A speed and pressure ratio determination unit 502, configured to determine the pressure ratio of the compressor according to the compressor inlet total pressure and the compressor outlet total pressure in the operating parameters, determine the reduced speed according to the physical speed and the inlet total temperature of the compressor, and adjust the switch state of the interstage air release valve according to the reduced speed and the operating state; A control line group matching unit 503, used to determine the control line group currently matched by the compressor according to the operating parameters, operating status and the switch status of the inter-stage air release valve; The first adjustment unit 504A is used to adjust several other valves of the compressor according to the reduced speed, pressure ratio and the start-stop control line group when the compressor matches the start-stop control line group; The second adjustment unit 504B is used to adjust 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.

[0078] In another embodiment, the surge boundary includes a first surge boundary and a second surge boundary, wherein the first surge boundary is used to characterize the maximum value of the pressure ratio of the compressor at different converted speeds, and the second surge boundary is used to characterize the maximum value of the pressure ratio of the compressor at different inlet guide vane openings at the rated speed; the compressor pre-sets the surge margin of each control line in the control line group; The control line group is set by preset surge boundary and surge margin, including: Determining a first surge line SL according to a preset first surge boundary, wherein the first surge boundary is used to characterize a maximum pressure ratio of the compressor at different reduced speeds; Determining other first surge control lines according to the reserved first surge margin and the first surge line SL, wherein 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 line groups; Determining a second surge line SL according to a 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 a rated speed; Determining other second surge control lines according to the reserved second surge margin and the second surge line SL, wherein 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 line groups form the continuous operation control line group.

[0079] In another embodiment, the plurality of other valves include an exhaust air supply valve and an exhaust vent valve, and the device further includes: The other valve adjustment unit 505 is used to detect the gas supply demand of the downstream process when the compressor is continuously running at the rated speed, and adjust the exhaust air supply valve, the exhaust vent valve and the inlet adjustable guide vane opening according to the gas supply demand, wherein the gas supply demand includes the gas supply pressure demand and the gas supply flow demand.

[0080] In another embodiment, determining other first surge control lines according to the reserved first surge margin and the first surge line SL comprises: pass Calculate the control line pressure ratio of other first surge control lines under different converted speeds, and determine the corresponding other first surge control lines according to the control line pressure ratio and the converted speed, wherein: is the pressure ratio of the first surge line SL at the reduced speed, is the control line pressure ratio of the other first surge control line at the converted speed, and SM is the surge margin.

[0081] In another embodiment, the plurality of other valves include an exhaust air supply valve, and the device further includes: The independent start-stop unit 506 is used to control the exhaust air supply valve and the exhaust vent valve to cut off the connection between the compressor and the downstream process flow before the compressor is started or stopped.

[0082] The above-mentioned embodiment of the present invention provides a control method for an axial flow compressor provided with inter-stage air bleed, and based on the method, provides an axial flow compressor control device provided with inter-stage air bleed. Through the above-mentioned method and device, the problem that the existing axial flow compressor control method lacks the operation and control of the inter-stage air bleed related valves and is not suitable for this type of compressor unit is solved.

[0083] This embodiment also discloses a computer device, which includes a processor and a memory, wherein the memory stores at least one instruction, and the at least one instruction is loaded and executed by the processor to implement any of the above-mentioned axial flow compressor control methods with inter-stage bleed air.

[0084] In addition, in the above-mentioned example implementation of the axial-flow compressor control device with inter-stage bleed, the logical division of each program module is only an example. In actual application, the above-mentioned functions can be assigned to different program modules as needed, for example, for the configuration requirements of the corresponding hardware or the convenience of software implementation. That is, the internal structure of the axial-flow compressor control device with inter-stage bleed is divided into different program modules to complete all or part of the functions described above.

[0085] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A control method for an axial flow compressor provided with interstage bleed, characterized in that: The compressor comprises an interstage bleed valve and several other valves and corresponding ventilation pipelines, and the compressor sets a control line group through a preset surge boundary, and the control line group comprises a start-stop control line group and a continuous operation control line group; The method comprises: Determine the operating parameters and operating state of the compressor, wherein the operating parameters include the compressor inlet total pressure, the compressor outlet total pressure, the physical speed, the compressor inlet total temperature and the inlet guide vane opening, and the operating state includes the startup process, continuous operation and shutdown process; The pressure ratio of the compressor is determined by the compressor inlet total pressure and the compressor outlet total pressure in the operating parameters, the reduced speed is determined according to the physical speed and the inlet total temperature of the compressor, and the switch state of the interstage air release valve is adjusted according to the reduced speed and the operating state; Determine the control line group currently matched by the compressor through the operating parameters, the operating state and the switch state of the inter-stage air bleed valve; When the compressor matches the start-stop control line group, several other valves of the compressor are adjusted according to the reduced speed, pressure ratio and the start-stop control line group; When the compressor matches the continuous operation control line group, several other valves of the compressor are adjusted according to the inlet guide vane opening, the pressure ratio and the continuous operation control line group.

2. The method according to claim 1, characterized in that The surge boundary includes a first surge boundary and a second surge boundary, wherein the first surge boundary is used to characterize the maximum value of the pressure ratio of the compressor at different reduced speeds, and the second surge boundary is used to characterize the maximum value of the pressure ratio of the compressor at different inlet guide vane openings at rated speed; the compressor pre-sets the surge margin of each control line in the control line group; The control line group is set by the preset surge boundary, comprising: Determining a first surge line SL according to a preset first surge boundary, and determining other first surge control lines according to the surge margin and the first surge line SL, wherein 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 line groups; Determining a second surge line SL according to a preset second surge boundary, and determining other second surge control lines according to the surge margin and the second surge line SL, wherein 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 line groups form the continuous operation control line group.

3. The method according to claim 1, characterized in that: The plurality of other valves include an exhaust air supply valve and an exhaust vent valve, and the method further includes: When the compressor runs continuously at the rated speed, the air supply demand of the downstream process is detected, and the exhaust air supply valve, the exhaust vent valve and the inlet adjustable guide vane opening are adjusted according to the air supply demand, wherein the air supply demand includes the air supply pressure demand and the air supply flow demand.

4. The method according to claim 2, characterized in that: The determining other first surge control lines according to the reserved first surge margin and the first surge line SL comprises: pass Calculate the control line pressure ratio of other first surge control lines under different converted speeds, and determine the corresponding other first surge control lines according to the control line pressure ratio and the converted speed, wherein: is the pressure ratio of the first surge line SL at the reduced speed, is the control line pressure ratio of the other first surge control line at the converted speed, and SM is the surge margin.

5. The method according to claim 1, characterized in that The plurality of 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 cut off the connection between the compressor and the downstream process flow.

6. A control device for an axial flow compressor provided with interstage bleed, characterized in that: The compressor comprises an interstage bleed valve and several other valves and corresponding ventilation pipelines, and the compressor sets a control line group through a preset surge boundary, and the control line group comprises a start-stop control line group and a continuous operation control line group; the device comprises: a parameter state determination unit, configured to determine the operating parameters and operating state of the compressor, wherein the operating parameters include the compressor inlet total pressure, the compressor outlet total pressure, the physical speed, the compressor inlet total temperature and the inlet guide vane opening, and the operating state includes the startup process, continuous operation and shutdown process; a speed and pressure ratio determination unit, configured to determine the pressure ratio of the compressor according to the compressor inlet total pressure and the compressor outlet total pressure in the operating parameters, determine the reduced speed according to the physical speed and the inlet total temperature of the compressor, and adjust the switch state of the interstage air release valve according to the reduced speed and the operating state; A control line group matching unit, used to determine the control line group currently matched by the compressor according to the operating parameters, operating status and the switch status of the inter-stage air release valve; A first adjustment unit, used for adjusting a plurality of other valves of the compressor according to the reduced speed, the pressure ratio and the start-stop control line group when the compressor matches 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, the pressure ratio and the continuous operation control line group when the compressor matches the continuous operation control line group.

7. The device according to claim 6, characterized in that The surge boundary includes a first surge boundary and a second surge boundary, wherein the first surge boundary is used to characterize the maximum value of the pressure ratio of the compressor at different reduced speeds, and the second surge boundary is used to characterize the maximum value of the pressure ratio of the compressor at different inlet guide vane openings at rated speed; the compressor pre-sets the surge margin of each control line in the control line group; The control line group is set by preset surge boundary and surge margin, including: Determining a first surge line SL according to a preset first surge boundary, wherein the first surge boundary is used to characterize a maximum pressure ratio of the compressor at different reduced speeds; Determining other first surge control lines according to the reserved first surge margin and the first surge line SL, wherein 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 line groups; Determining a second surge line SL according to a 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 a rated speed; Determining other second surge control lines according to the reserved second surge margin and the second surge line SL, wherein 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 line groups form the continuous operation control line group.

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

9. The device according to claim 7, characterized in that The determining other first surge control lines according to the reserved first surge margin and the first surge line SL comprises: pass Calculate the control line pressure ratio of other first surge control lines under different converted speeds, and determine the corresponding other first surge control lines according to the control line pressure ratio and the converted speed, wherein: is the pressure ratio of the first surge line SL at the reduced speed, is the control line pressure ratio of the other first surge control line at the converted speed, and SM is the surge margin.

10. The device according to claim 6, characterized in that The plurality of other valves include an exhaust air supply valve, and the device further includes: The independent start-stop unit is used to control the exhaust air supply valve and the exhaust vent valve to cut off the connection between the compressor and the downstream process flow before the compressor is started or stopped.

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