Steam turbine system for regulating steam inlet pressure and control method thereof

Abstract

The present application relates to the field of steam turbine control technology, and in particular to a steam turbine system and control method for regulating steam inlet pressure. The steam turbine system includes a steam turbine and a compressor, as well as an electronic governor and a control module that communicate with each other; the process gas outlet of the chemical reactor is connected to the compressor through a first pipeline, and the steam outlet is connected to the extraction condensing steam turbine through a second pipeline; the second pipeline is provided with a quick-closing valve that communicates with the control module and a steam inlet regulating valve that communicates with the electronic governor, an overflow pipeline is connected between the high-pressure section and the low-pressure section of the steam turbine, and an overflow valve that communicates with the electronic governor is provided on it, and the steam extraction port of the high-pressure section is connected to the steam extraction pipeline, and a steam extraction check valve that communicates with the control module is provided on it; the steam turbine system of the present application can achieve the effect of maintaining both the forward pressure and the load, and also proposes a new solution for handling excess steam in the chemical reactor.

Description

Technical Field

[0001] The present application relates to the technical field of steam turbine control, and in particular to a steam turbine system and a control method for regulating steam inlet pressure. Background Art

[0002] Steam turbines are widely used in the fields of power generation and industrial drive. In the petroleum and chemical industries in the field of industrial drive, there is a chemical reactor that produces both steam and process gas, such as the cracking furnace of the ethylene cracking unit, the synthesis reaction tower of the methanol synthesis process, etc. The process gas produced by the reactor is sent to the compressor, which is compressed and pressurized by the compressor and then sent to the downstream equipment. The steam produced by the reactor is sent to the extraction condensing steam turbine used as the driving machine of the compressor.

[0003] At present, extraction condensing steam turbines in the industrial drive field all adopt a control method of adjusting the extraction pressure, but the system using this control method cannot achieve the effect of maintaining both the forward pressure and the load, and the surplus steam of the chemical reactor is sent to other steam-using equipment at a higher pressure level through the upstream of the steam turbine. Summary of the invention

[0004] The purpose of the present invention is to provide a steam turbine system and control method for adjusting the steam inlet pressure, so as to achieve the effect of maintaining both the forward pressure and the load by adjusting the steam inlet pressure of the steam turbine, and propose a new solution for processing excess steam in a chemical reactor.

[0005] The present invention provides a steam turbine system for regulating steam inlet pressure, comprising a steam turbine, a compressor, an electronic speed governor and a control module;

[0006] The air inlet of the compressor is used to communicate with the process gas outlet of the chemical reactor through a first pipeline, the steam turbine is an extraction condensing steam turbine, and the steam inlet of the high-pressure section of the steam turbine is used to communicate with the steam outlet of the chemical reactor through a second pipeline;

[0007] The second pipeline is provided with a quick closing valve and a steam inlet regulating valve, an overflow pipeline is connected between the high-pressure section and the low-pressure section of the steam turbine, an overflow valve is provided on the overflow pipeline, the steam extraction port of the high-pressure section of the steam turbine is used to connect to the steam extraction pipeline, and a steam extraction check valve is provided on the steam extraction pipeline;

[0008] The control module is connected to the electronic speed governor for communication, the steam inlet regulating valve and the overflow valve are connected to the electronic speed governor for communication, and the quick-closing valve and the steam extraction check valve are connected to the control module for communication.

[0009] Furthermore, a first pressure detection component is provided on the first pipeline to obtain the inlet pressure of the compressor, and the first pressure detection component is communicatively connected with the electronic speed regulator;

[0010] A second pressure detection component is provided on the second pipeline to obtain the steam inlet pressure of the steam turbine, and the second pressure detection component is communicatively connected with the electronic speed governor;

[0011] The steam extraction pipeline is provided with a third pressure detection component to obtain the steam extraction pressure of the steam turbine, and the third pressure detection component is communicatively connected with the control module.

[0012] Furthermore, the steam turbine is provided with a speed detection component to obtain the speed of the steam turbine, and the speed detection component is communicatively connected with the electronic speed governor.

[0013] Furthermore, a first temperature detection component is provided on the overflow pipeline to obtain the steam extraction temperature of the steam turbine, and the first temperature detection component is communicatively connected with the control module;

[0014] The exhaust port of the low-pressure section of the steam turbine is connected to an exhaust pipeline, and a second temperature detection component is provided on the exhaust pipeline to obtain the exhaust temperature of the steam turbine. The second temperature detection component is communicatively connected with the control module.

[0015] The present application also provides a steam turbine control method, which is used for the steam turbine system for adjusting the steam inlet pressure as described in any one of the above items; the electronic speed governor is configured with a speed control mode, and when the electronic speed governor executes the speed control mode, the steam turbine control method comprises the following steps:

[0016] The electronic speed governor controls the overflow valve to be fully open, and the control module controls the extraction steam check valve to be closed;

[0017] Preset the normal compressor inlet pressure P for the electronic speed controller A1 and turbine speed N A , and obtain the compressor inlet pressure P in real time A1 ′ and turbine speed N A ′;

[0018] When P A1 ′ is greater than P A1 When the electronic speed governor controls the steam inlet regulating valve to open wider, N A ' is greater than N A ;

[0019] When P A1 ′ is less than P A1 When the electronic speed governor controls the steam inlet regulating valve to close, N A ' is less than N A .

[0020] Furthermore, the electronic speed governor is also configured with a forward pressure and speed control mode. When the electronic speed governor executes the forward pressure and speed control mode, the steam turbine control method includes the following steps:

[0021] Preset the normal compressor inlet pressure P for the electronic speed controller B1 , Steam turbine inlet pressure P B2 and turbine speed N B , and obtain the compressor inlet pressure P in real time B1 ', turbine inlet steam pressure P B2 ′ and turbine speed N B ′;

[0022] When P B1 ′ is greater than P B1 When P B2 ′ is also greater than P B2 , the electronic speed governor controls the steam inlet regulating valve to open wide, so that N B ' is greater than N B When P B2 'Restore to P B2 Afterwards, the electronic speed governor controls the overflow valve to close;

[0023] When P B1 ′ is less than P B1 When P B2 ′ is also smaller than P B2 , the electronic speed governor controls the steam inlet regulating valve to close, so that N B ' is less than N B When P B2 'Restore to P B2 Afterwards, the electronic speed governor controls the overflow valve to open wider.

[0024] Furthermore, the electronic speed regulator is equipped with underload protection measures:

[0025] When the electronic speed regulator executes the forward pressure and speed control mode, when the opening degree H of the overflow valve is LP ≤H LP ', while the turbine speed increases and the acceleration rate A N ≥A N ', the electronic speed regulator switches from the forward pressure and speed control mode to the speed control mode;

[0026] Among them, H LP ' is the minimum opening of the overflow valve, A N ′ is the maximum permissible acceleration rate.

[0027] Furthermore, the electronic speed governor is equipped with a protection measure for low pressure of the steam extraction pipeline:

[0028] When the electronic speed governor executes the forward pressure and speed control mode, when the extraction steam pressure P3≤95%P 3min , while the turbine speed decreases and the acceleration rate A N ≥A N ', the electronic speed regulator switches from the forward pressure and speed control mode to the speed control mode;

[0029] Among them, P 3min A is the lower limit of extraction steam pressure fluctuation, N ′ is the maximum permissible acceleration rate.

[0030] Furthermore, the electronic speed governor is equipped with high extraction and exhaust steam temperature protection measures:

[0031] When the electronic speed governor executes the forward pressure and speed control mode, when the extraction steam temperature T1 ≥ T1′ or the exhaust steam temperature T2 ≥ T2′, the electronic speed governor switches to the speed control mode, and when the extraction steam temperature and the exhaust steam temperature return to the permitted level, the electronic speed governor switches back to the forward pressure and speed control mode;

[0032] If T1 and T2 continue to increase after the electronic speed governor switches to the speed control mode, the control module will issue a turbine shutdown command to control the quick-closing valve to quickly shut down the turbine;

[0033] Wherein, T1′ and T2′ are respectively the extraction steam temperature value and the exhaust steam temperature value calculated according to the Flugel formula.

[0034] Furthermore, the electronic speed regulator is equipped with load overload protection measures:

[0035] When the electronic speed regulator executes the forward pressure and speed control mode, when the overflow valve opening H LP ≥H LP ', while the extraction steam pressure P3≤P 3min , the electronic speed regulator switches from the forward pressure and speed control mode to the speed control mode;

[0036] Among them, H LP ' is the maximum opening of the overflow valve, P 3min It is the lower limit of extraction steam pressure fluctuation.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] The steam turbine system provided by the present invention comprises a steam turbine, a compressor, an electronic speed governor and a control module; the air inlet of the compressor is used to be connected to the process gas outlet of a chemical reactor through a first pipeline, the steam turbine is an extraction condensing steam turbine, and the steam inlet of the high-pressure section of the steam turbine is used to be connected to the steam outlet of the chemical reactor through a second pipeline; a quick-closing valve and a steam inlet regulating valve are provided on the second pipeline, an overflow pipeline is connected between the high-pressure section and the low-pressure section of the steam turbine, an overflow valve is provided on the overflow pipeline, the steam extraction port of the high-pressure section of the steam turbine is used to be connected to the steam extraction pipeline, and a steam extraction check valve is provided on the steam extraction pipeline.

[0039] The control module is connected to the electronic speed governor so that the control module and the electronic speed governor can communicate with each other. The steam inlet regulating valve and the overflow valve are connected to the electronic speed governor respectively, and the quick closing valve and the steam extraction check valve are connected to the control module respectively. The steam turbine system of the present application adopts an extraction-condensing steam turbine as the driving machine of the compressor, and proposes a new solution for processing surplus steam from a chemical reactor, namely, extracting surplus steam from the steam extraction port of the high-pressure section of the steam turbine and sending it to other steam-using equipment at a lower pressure level, rather than providing it to the outside from the upstream of the steam turbine, so that the process gas produced by the chemical reactor is all sent to the compressor, and the produced steam is all sent to the steam turbine; since the steam sent to the steam turbine and the process gas sent to the compressor come from the same chemical reactor, and the produced steam and process gas are all sent to one steam turbine and one compressor, the steam inlet pressure of the steam turbine fluctuates in a positive correlation with the inlet pressure of the compressor, that is, the steam inlet pressure of the steam turbine and the inlet pressure of the compressor increase or decrease synchronously, so that the steam turbine system of the present application can adopt a control method for adjusting the steam inlet pressure, which can not only realize the adjustment of the steam inlet pressure, but also ensure the power required by the output compressor, thereby achieving the effect of maintaining both the forward pressure and the load. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0041] Figure 1 A schematic structural diagram of a steam turbine system provided in an embodiment of the present invention.

[0042] Reference numerals:

[0043] 1-Chemical reactor, 2-Quick closing valve, 3-High pressure section, 4-Low pressure section, 5-Steam inlet regulating valve, 6-Overflow valve, 7-Steam extraction check valve, 8-Compressor, 9-Electronic speed governor, 10-Control module. DETAILED DESCRIPTION

[0044] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0045] The components of the embodiments of the present invention generally described and shown in the drawings herein may be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention.

[0046] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of the present invention.

[0047] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0048] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0049] Refer to the following Figure 1 A steam turbine system and a control method for adjusting steam inlet pressure according to some embodiments of the present application are described.

[0050] A first aspect of the present application provides a steam turbine system for regulating steam inlet pressure, such as Figure 1 As shown, the steam turbine system for regulating the steam inlet pressure includes a steam turbine, a compressor 8, an electronic speed governor 9 and a control module 10.

[0051] The air inlet of the compressor 8 is connected to the process gas outlet of the chemical reactor 1 through the first pipeline, wherein the chemical reactor 1 is a reactor that produces both process gas and steam. For example, the chemical reactor 1 can be a cracking furnace of an ethylene cracking unit or a synthesis reaction tower of a methanol synthesis process, etc. The raw materials are cracked or synthesized into process gas after endothermic or exothermic chemical reaction in the chemical reactor 1, and water is heated into high-pressure steam in the chemical reactor 1; the process gas produced by the chemical reactor 1 can be sent to the compressor 8 through the first pipeline, and then compressed and pressurized by the compressor 8 and sent to downstream equipment.

[0052] The steam turbine serves as a driving machine for the compressor 8, and the steam produced by the chemical reactor 1 can be sent to the steam turbine to convert the thermal energy of the steam into mechanical energy through the steam turbine to drive the compressor 8; specifically, the steam turbine is an extraction condensing steam turbine, and the steam turbine includes two expansion sections, namely a high-pressure section 3 and a low-pressure section 4, wherein the steam inlet of the high-pressure section 3 is connected to the steam outlet of the chemical reactor 1 through a second pipeline, so that the steam produced by the chemical reactor 1 can be sent to the steam turbine through the second pipeline.

[0053] As the steam inlet pipeline of the steam turbine, the second pipeline is serially connected with a quick-closing valve 2 and a steam inlet regulating valve 5 in sequence. The quick-closing valve 2 is used to cut off the main steam inlet of the steam turbine to shut down the steam turbine. The steam inlet regulating valve 5 is used to adjust the steam inlet amount of the high-pressure section 3 of the steam turbine, and by adjusting the steam inlet amount of the high-pressure section 3, the rotation speed of the steam turbine, the steam inlet pressure and the inlet pressure of the compressor 8 can be adjusted.

[0054] For example, when the steam inlet regulating valve 5 is opened, the steam inlet amount of the high-pressure section 3 will increase, the speed of the steam turbine will increase, and the steam inlet pressure of the steam turbine and the inlet pressure of the compressor 8 will decrease; when the steam inlet regulating valve 5 is closed, the steam inlet amount of the high-pressure section 3 will decrease, the speed of the steam turbine will decrease, and the steam inlet pressure of the steam turbine and the inlet pressure of the compressor 8 will increase.

[0055] Preferably, there may be multiple steam inlet regulating valves 5 , and the multiple steam inlet regulating valves 5 may be arranged in parallel, and a set of lever mechanisms may be provided to operate the multiple steam inlet regulating valves 5 to be opened or closed in sequence through the lever mechanisms.

[0056] In this embodiment, an overflow pipeline is connected between the high-pressure section 3 and the low-pressure section 4 of the turbine, and an overflow valve 6 is provided on the overflow pipeline. The overflow valve 6 can be used to adjust the steam intake amount of the low-pressure section 4 of the turbine, and by adjusting the steam intake amount of the low-pressure section 4, the speed of the turbine, the steam intake pressure and the inlet pressure of the compressor 8 can be adjusted.

[0057] For example, when the relief valve 6 is closed, the speed of the turbine will decrease, and the steam inlet pressure of the turbine and the inlet pressure of the compressor 8 will increase; when the relief valve 6 is opened, the speed of the turbine will increase, and the steam inlet pressure of the turbine and the inlet pressure of the compressor 8 will decrease.

[0058] Preferably, the number of the overflow valve 6 is one or two. When the number of the overflow valve 6 is two, the two overflow valves 6 are arranged in parallel.

[0059] In this embodiment, the exhaust port of the low-pressure section 4 of the steam turbine is connected to an exhaust pipeline, the extraction port of the high-pressure section 3 is connected to an extraction pipeline, and an extraction check valve 7 is provided on the extraction pipeline. The extraction check valve 7 is used to prevent the steam in the extraction pipeline from flowing back into the low-pressure section 4 of the steam turbine, thereby isolating the steam turbine from the extraction pipeline; preferably, the extraction check valve is a hydraulically driven valve or a gas driven valve.

[0060] In this embodiment, the electronic speed governor 9 is used to receive the speed signal of the turbine, the steam inlet pressure signal of the turbine and the inlet pressure signal of the compressor 8. At the same time, the electronic speed governor 9 can output control signals to the steam inlet regulating valve 5 and the overflow valve 6.

[0061] For example, a first pressure detection device is provided on the first pipeline serving as the process gas inlet pipeline of the compressor 8 to obtain the inlet pressure of the compressor 8 through the first pressure detection device; the electronic speed regulator 9 is communicatively connected with the first pressure detection device so that the electronic speed regulator 9 can receive the real-time pressure of the compressor 8 inlet measured by the first pressure detection device.

[0062] For example, a second pressure detecting device is provided on the second pipeline serving as the steam inlet pipeline of the steam turbine. Specifically, the second pressure detecting device is provided on the pipeline between the steam outlet of the chemical reactor 1 and the quick-closing valve 2 to obtain the steam inlet pressure of the steam turbine through the second pressure detecting device; the electronic speed governor 9 is communicatively connected with the second pressure detecting device so that the electronic speed governor 9 can receive the real-time steam inlet pressure of the turbine measured by the second pressure detecting device.

[0063] For example, a speed detection device is provided at the front end of the high pressure section 3 of the steam turbine, so as to obtain the speed of the steam turbine through the speed detection device, which is also the speed value of the steam turbine-compressor 8 group; the electronic speed governor 9 is connected to the speed detection device in communication, so that the electronic speed governor 9 can receive the real-time speed of the steam turbine-compressor 8 group measured by the speed detection device. Preferably, the speed detection device is a Hall effect speed sensor, the number of which can be three, and its signal is sent to the electronic speed governor 9 in a "three-in-one" mode.

[0064] For example, the electronic speed governor 9 is respectively connected to the steam inlet regulating valve 5 and the overflow valve 6 for communication, so that the electronic speed governor 9 can transmit control signals to the steam inlet regulating valve 5 and the overflow valve 6 to control the opening of the steam inlet regulating valve 5 and the overflow valve 6.

[0065] In this embodiment, the control module 10 is communicatively connected with the electronic speed governor 9 so that the control module 10 and the electronic speed governor 9 can communicate with each other; at the same time, the control module 10 is used to receive various monitoring signals of the turbine and the compressor 8, including but not limited to extraction temperature signals, exhaust temperature signals and extraction pressure signals, and the control module 10 can output control signals to the quick-closing valve 2 and the extraction check valve 7.

[0066] For example, a first temperature detection component is provided on the overflow pipeline between the high-pressure section 3 and the low-pressure section 4 of the steam turbine. Specifically, the first temperature detection component is provided in front of the overflow valve 6 to obtain the extraction temperature of the high-pressure section 3 of the steam turbine through the first temperature detection component; the control module 10 is connected to the first temperature detection component in communication, so that the control module 10 can receive the real-time value of the extraction temperature measured by the first temperature detection component. Preferably, the number of the first temperature detection components can be three. When the extraction temperature is too high, the signals of the three first temperature detection components are sent to the control module 10 in a two-out-of-three mode, and the turbine shutdown command is triggered.

[0067] For example, a second temperature detection component is provided on the exhaust pipe of the low-pressure section 4 of the steam turbine to obtain the exhaust temperature of the low-pressure section 4 of the steam turbine through the second temperature detection component; the control module 10 is connected to the second temperature detection component in communication, so that the control module 10 can receive the real-time value of the exhaust temperature measured by the second temperature detection component. Preferably, the number of the second temperature detection components can be three, and when the exhaust temperature is too high, the signals of the three second temperature detection components are sent to the control module 10 in a two-out-of-three mode, and the turbine shutdown command is triggered.

[0068] For example, a third pressure detection device is provided on the steam extraction pipeline between the steam extraction port of the high-pressure section 3 of the steam turbine and the steam extraction check valve 7 to obtain the steam extraction pressure of the steam turbine through the third pressure detection device; the control module 10 is communicatively connected with the third pressure detection device, so that the control module 10 can receive the real-time steam extraction pressure of the steam turbine measured by the third pressure detection device.

[0069] For example, the control module 10 is respectively connected to the steam extraction check valve 7 and the quick-closing valve 2 for communication, so that the control module 10 can transmit control signals to the steam extraction check valve 7 and the quick-closing valve 2 to control the opening or closing of the steam extraction check valve 7 and the quick-closing valve 2.

[0070] The steam turbine system of the present application is capable of executing the speed control mode:

[0071] The electronic governor is preset with normal compressor inlet pressure and turbine speed, and the electronic governor controls the overflow valve to be fully open, and the control module controls the extraction steam check valve to be closed.

[0072] When the actual pressure at the compressor inlet is greater than the preset pressure, the electronic governor can control the steam inlet regulating valve to open wider; as the steam inlet regulating valve is opened wider, the actual speed of the turbine will increase, causing the compressor inlet pressure to drop and return to the preset normal value. When the compressor inlet pressure is restored, the turbine speed will gradually return to normal.

[0073] When the actual pressure at the compressor inlet is lower than the preset pressure, the electronic governor can control the steam inlet regulating valve to close; as the steam inlet regulating valve is closed, the actual speed of the turbine will decrease, so that the compressor inlet pressure will increase and return to the preset normal value. When the compressor inlet pressure is restored, the speed of the turbine will gradually return to normal.

[0074] The steam turbine system of the present application can also execute forward pressure and speed control modes:

[0075] The electronic governor is preset with normal turbine inlet steam pressure, compressor inlet pressure and turbine speed.

[0076] When the steam output of the chemical reactor increases and the steam inlet pressure of the turbine increases, the inlet pressure of the compressor also increases; at this time, the electronic governor is used to control the steam inlet regulating valve to open wider, so that the steam inlet pressure of the turbine drops and returns to the preset normal value; at the same time, due to the opening of the steam inlet regulating valve, the speed of the turbine will increase, so that the inlet pressure of the compressor drops and returns to the preset normal value. When the inlet pressure of the compressor is restored, the speed of the turbine will gradually return to normal.

[0077] When the steam output of the chemical reactor becomes smaller and the steam inlet pressure of the turbine decreases, the inlet pressure of the compressor also decreases; at this time, the electronic governor is used to control the steam inlet regulating valve to be closed, so that the steam inlet pressure of the turbine increases and returns to the preset normal value; at the same time, since the steam inlet regulating valve is closed, the speed of the turbine will decrease, so that the inlet pressure of the compressor increases and returns to the preset normal value. When the inlet pressure of the compressor is restored, the speed of the turbine will gradually return to normal.

[0078] Therefore, the steam turbine system of the present application adopts an extraction-condensing steam turbine as the driving machine of the compressor 8, and proposes a new scheme for processing surplus steam of the chemical reactor, that is, extracting surplus steam from the steam extraction port of the high-pressure section 3 of the steam turbine and sending it to other steam-using equipment at a lower pressure level, rather than providing it to the outside from the upstream of the steam turbine, so that the process gas produced by the chemical reactor 1 is all sent to the compressor 8, and the produced steam is all sent to the steam turbine; because the steam sent to the steam turbine and the process gas sent to the compressor 8 come from the same chemical reactor 1, and the produced steam and process gas are all sent to one steam turbine and one compressor 8, the steam inlet pressure of the steam turbine fluctuates in a positive correlation with the inlet pressure of the compressor 8, that is, the steam inlet pressure of the steam turbine and the inlet pressure of the compressor 8 increase or decrease synchronously, so that the steam turbine system of the present application can adopt a control method for adjusting the steam inlet pressure, which can not only realize the adjustment of the steam inlet pressure, but also ensure the power required by the output compressor 8, so as to achieve the effect of both maintaining the forward pressure and the load.

[0079] A second aspect of the present application provides a steam turbine control method, which is used for the steam turbine system of any of the above embodiments.

[0080] The electronic speed governor is configured with a ratio logic circuit capable of receiving a speed control signal and a forward pressure control signal and a relief valve bypass decoupling control circuit, and thus has two modes, one is a speed control mode, and the other is a forward pressure and speed control mode.

[0081] When the electronic speed governor executes the speed control mode, the forward pressure and speed control modes are invalid, and the turbine control method includes the following steps:

[0082] A control signal is output to the relief valve through the relief valve bypass decoupling control circuit of the electronic governor to control the relief valve to be fully opened, and a control signal is output to the steam extraction check valve through the control module to control the steam extraction check valve to be closed;

[0083] Preset the normal compressor inlet pressure P for the electronic speed controller A1 and turbine speed N A The actual compressor inlet pressure P is obtained in real time through the first pressure detection element and the speed detection element. A1 ′ and turbine speed N A ′;

[0084] The electronic speed controller compares the actual pressure information with the preset pressure information. A1 ′ is greater than P A1 When the electronic speed governor sends an opening command to the steam inlet regulating valve to control the steam inlet regulating valve to open wider; due to the opening of the steam inlet regulating valve, the actual speed of the steam turbine N A ′ will be greater than N A , so that P A1′ decreases and returns to P A1 When P A1 'Restore to P A1 After that, the actual speed of the turbine will also change from N A ′ gradually recovers to N A .

[0085] When P A1 ′ is less than P A1 When the electronic speed governor sends a closing command to the steam inlet regulating valve, the steam inlet regulating valve is controlled to close. As the steam inlet regulating valve is closed, the actual speed of the steam turbine N A ′ will be less than N A , so that P A1 ′ increases and returns to P A1 When P A1 'Restore to P A1 After that, the actual speed of the turbine will also change from N A ′ gradually recovers to N A .

[0086] Therefore, when the electronic speed governor executes the speed control mode, the electronic speed governor can control the speed of the turbine and the inlet pressure of the compressor by controlling the opening of the steam inlet regulating valve.

[0087] When the electronic speed governor executes the forward pressure and speed control mode, the turbine control method includes the following steps:

[0088] The opening of the steam inlet regulating valve and the overflow valve is controlled by coupling the ratio logic circuit of the electronic governor;

[0089] Preset the normal compressor inlet pressure P for the electronic speed controller B1 , Steam turbine inlet pressure P B2 and turbine speed N B The actual compressor inlet pressure P is obtained in real time through the first pressure detection element, the second pressure detection element and the speed detection element. B1 ', turbine inlet steam pressure P B2 ′ and turbine speed N B ′(It should be noted that at this time P B1 Can be combined with the above P A1 Same, N B Can be combined with the above N A same);

[0090] The electronic speed governor compares the actual pressure information with the preset pressure information. Since the reactor of the steam turbine system of the present application sends all the steam produced to the steam turbine and all the process gas to the compressor, the steam inlet pressure of the steam turbine fluctuates in a positive correlation with the inlet pressure of the compressor, that is, the steam inlet pressure of the steam turbine and the inlet pressure of the compressor increase or decrease synchronously. Therefore, when the steam and process gas output of the chemical reactor increases, the P can be obtained by comparing the electronic speed governor. B1 ′ is greater than P B1 , while P B2 ′ is also greater than P B2 At this time, the electronic speed governor sends an opening command to the steam inlet regulating valve to control the steam inlet regulating valve to open wider. As the steam inlet regulating valve is opened wider, P B2 ′ decreases and returns to P B2 , the actual speed of the turbine N B ' will be greater than the preset N B , so that P B1 ′ decreases and returns to P B1 When P B1 'Restore to P B1 , P B2 'Restore to P B2 After that, the electronic speed controller sends a closing command to the overflow valve to control the overflow valve to close, so that N B 'Restore to the preset N B At this time, the amount of surplus steam sent out through the steam extraction pipeline will increase.

[0091] When the steam and process gas output of the chemical reactor decreases, the P can be obtained by comparing the electronic speed regulator. B1 ′ is less than P B1 , while P B2 ′ is also smaller than P B2 At this time, the electronic speed governor sends a closing command to the steam inlet regulating valve to control the steam inlet regulating valve to close. As the steam inlet regulating valve is closed, P B2 ′ rises and returns to P B2 , the actual speed of the turbine N B ' will be less than the preset N B , so that P B1 ′ rises and returns to P B1 When P B1 'Restore to P B1 , P B2 'Restore to P B2 After that, the electronic speed regulator controls the overflow valve to open wider, so that N B 'Rise and return to the preset N B At this time, the amount of surplus steam sent out through the steam extraction pipeline will become smaller.

[0092] Therefore, when the electronic speed governor executes the forward pressure and speed control mode, the electronic speed governor can control the steam inlet pressure, speed and compressor inlet pressure of the turbine by controlling the opening of the steam inlet regulating valve and the overflow valve.

[0093] In this embodiment, preferably, the electronic speed regulator is also equipped with a load underload protection measure:

[0094] When the electronic speed controller is in the forward pressure and speed control mode, when the opening of the overflow valve is H LP ≤H LP ', while the turbine speed increases and the acceleration rate A N ≥A N ′, the electronic speed regulator will switch from the forward pressure and speed control mode to the speed control mode; LP ' is the minimum opening of the overflow valve, A N ′ is the maximum permissible acceleration rate.

[0095] In this embodiment, preferably, the electronic speed governor is also equipped with a low pressure protection measure for the steam extraction pipeline:

[0096] When the electronic speed governor executes the forward pressure and speed control mode, when the extraction steam pressure P3≤95%P 3min , while the turbine speed decreases and the acceleration rate A N ≥A N ′, the electronic speed regulator will switch from the forward pressure and speed control mode to the speed control mode; where P 3min A is the lower limit of extraction steam pressure fluctuation, N ′ is the maximum permissible acceleration rate.

[0097] In this embodiment, preferably, the electronic speed governor is also equipped with high extraction and exhaust steam temperature protection measures:

[0098] When the electronic speed governor executes the forward pressure and speed control mode, since the surplus steam supplied from the extraction pipeline accounts for a large proportion of the total steam intake, the steam inlet regulating valve and the overflow valve are easily in a small opening state, causing the high-pressure section and the low-pressure section of the steam turbine to work in a blast state; in order to avoid the high-pressure section and the low-pressure section of the steam turbine from working in a blast state, when the extraction temperature T1 ≥ T1′ or the exhaust temperature T2 ≥ T2′, the electronic speed governor switches to the speed control mode; wherein T1′ and T2′ are the extraction temperature value and the exhaust temperature value calculated according to the Flügel formula, respectively.

[0099] When the opening of the steam inlet regulating valve or the overflow valve is restored to a larger opening, the extraction steam temperature and the exhaust steam temperature return to the permissible level, and the electronic speed governor switches back to the forward pressure and speed control mode.

[0100] If T1 and T2 continue to increase after the electronic speed governor switches to the speed control mode, the control module will issue a turbine shutdown command and control the quick-closing valve to quickly shut down the turbine.

[0101] In this embodiment, preferably, the electronic speed regulator is also equipped with load overload protection measures:

[0102] When the electronic speed regulator executes the forward pressure and speed control mode, when the overflow valve opening H LP ≥H LP ', while the extraction steam pressure P3≤P 3min When H LP ' is the maximum opening of the overflow valve, P 3min It is the lower limit of extraction steam pressure fluctuation.

[0103] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A steam turbine control method, used in a steam turbine system, wherein the steam turbine system is a steam turbine system for adjusting steam inlet pressure; characterized in that: The steam turbine system for regulating the steam inlet pressure comprises a steam turbine, a compressor, an electronic speed governor and a control module; The air inlet of the compressor is used to communicate with the process gas outlet of the chemical reactor through a first pipeline, the steam turbine is an extraction condensing steam turbine, and the steam inlet of the high-pressure section of the steam turbine is used to communicate with the steam outlet of the chemical reactor through a second pipeline; The second pipeline is provided with a quick closing valve and a steam inlet regulating valve, an overflow pipeline is connected between the high-pressure section and the low-pressure section of the steam turbine, an overflow valve is provided on the overflow pipeline, the steam extraction port of the high-pressure section of the steam turbine is used to connect to the steam extraction pipeline, and a steam extraction check valve is provided on the steam extraction pipeline; The control module is connected to the electronic speed governor in communication, the steam inlet regulating valve and the overflow valve are connected to the electronic speed governor in communication, and the quick-closing valve and the steam extraction check valve are connected to the control module in communication; A first pressure detection component is provided on the first pipeline to obtain the inlet pressure of the compressor, and the first pressure detection component is communicatively connected with the electronic speed regulator; The steam turbine is provided with a speed detection component to obtain the speed of the steam turbine, and the speed detection component is communicatively connected with the electronic speed governor; The electronic speed governor is configured with a speed control mode. When the electronic speed governor executes the speed control mode, the steam turbine control method comprises the following steps: The electronic speed governor controls the overflow valve to be fully open, and the control module controls the extraction steam check valve to be closed; Preset the normal compressor inlet pressure P for the electronic speed controller A1 and turbine speed N A , and obtain the compressor inlet pressure P in real time A1 ′ and turbine speed N A ′; When P A1 ′ is greater than P A1 When the electronic speed governor controls the steam inlet regulating valve to open wider, N A ' is greater than N A ; When P A1 ′ is less than P A1 When the electronic speed governor controls the steam inlet regulating valve to close, N A ' is less than N A .

2. The steam turbine control method according to claim 1, characterized in that: A second pressure detection component is provided on the second pipeline to obtain the steam inlet pressure of the steam turbine, and the second pressure detection component is communicatively connected with the electronic speed governor; The steam extraction pipeline is provided with a third pressure detection component to obtain the steam extraction pressure of the steam turbine, and the third pressure detection component is communicatively connected with the control module.

3. The steam turbine control method according to claim 2, characterized in that: A first temperature detection component is provided on the overflow pipeline to obtain the steam extraction temperature of the steam turbine, and the first temperature detection component is communicatively connected with the control module; The exhaust port of the low-pressure section of the steam turbine is connected to an exhaust pipeline, and a second temperature detection component is provided on the exhaust pipeline to obtain the exhaust temperature of the steam turbine. The second temperature detection component is communicatively connected with the control module.

4. The steam turbine control method according to claim 3, characterized in that: The electronic speed governor is also configured with a forward pressure and speed control mode. When the electronic speed governor executes the forward pressure and speed control mode, the steam turbine control method includes the following steps: Preset the normal compressor inlet pressure P for the electronic speed controller B1 , Steam turbine inlet pressure P B2 and turbine speed N B , and obtain the compressor inlet pressure P in real time B1 ', turbine inlet steam pressure P B2 ′ and turbine speed N B ′; When P B1 ′ is greater than P B1 When P B2 ′ is also greater than P B2 , the electronic speed governor controls the steam inlet regulating valve to open wide, so that N B ' is greater than N B When P B2 'Restore to P B2 Afterwards, the electronic speed governor controls the overflow valve to close; When P B1 ′ is less than P B1 When P B2 ′ is also smaller than P B2 , the electronic speed governor controls the steam inlet regulating valve to close, so that N B ' is less than N B When P B2 'Restore to P B2 Afterwards, the electronic speed governor controls the overflow valve to open wider.

5. The steam turbine control method according to claim 4, characterized in that: The electronic speed regulator is equipped with underload protection measures: When the electronic speed regulator executes the forward pressure and speed control mode, when the opening degree H of the overflow valve is LP ≤H LP ', while the turbine speed increases and the acceleration rate A N ≥A N ', the electronic speed regulator switches from the forward pressure and speed control mode to the speed control mode; Among them, H LP ' is the minimum opening of the overflow valve, A N ′ is the maximum permissible acceleration rate.

6. The steam turbine control method according to claim 4, characterized in that: The electronic speed governor is equipped with a protection measure for low pressure of the steam extraction pipeline: When the electronic speed governor executes the forward pressure and speed control mode, when the extraction steam pressure P3≤95%P 3min , while the turbine speed decreases and the acceleration rate A N ≥A N ', the electronic speed regulator switches from the forward pressure and speed control mode to the speed control mode; Among them, P 3min A is the lower limit of extraction steam pressure fluctuation, N ′ is the maximum permissible acceleration rate.

7. The steam turbine control method according to claim 4, characterized in that: The electronic speed governor is equipped with high extraction and exhaust steam temperature protection measures: When the electronic speed governor executes the forward pressure and speed control mode, when the extraction steam temperature T1 ≥ T1′ or the exhaust steam temperature T2 ≥ T2′, the electronic speed governor switches to the speed control mode, and when the extraction steam temperature and the exhaust steam temperature return to the permitted level, the electronic speed governor switches back to the forward pressure and speed control mode; If T1 and T2 continue to increase after the electronic speed governor switches to the speed control mode, the control module will issue a turbine shutdown command to control the quick-closing valve to quickly shut down the turbine; Wherein, T1′ and T2′ are respectively the extraction steam temperature value and the exhaust steam temperature value calculated according to the Flugel formula.

8. The steam turbine control method according to claim 4, characterized in that: The electronic speed regulator is equipped with load overload protection measures: When the electronic speed regulator executes the forward pressure and speed control mode, when the overflow valve opening H LP ≥H LP ', while the extraction steam pressure P3≤P 3min , the electronic speed regulator switches from the forward pressure and speed control mode to the speed control mode; Among them, H LP ' is the maximum opening of the overflow valve, P 3min It is the lower limit of extraction steam pressure fluctuation.

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