Waste heat boiler feed water control method and system and medium

Abstract

The embodiment of the invention provides a waste heat boiler feed water control method and system and a medium. The method comprises the steps that steam turbine operation condition information is obtained, and the steam turbine operation load is analyzed based on the steam turbine operation condition information; a matched water supply control mode is selected based on the steam turbine operation load, and a main pipe water supply differential pressure value is obtained in real time; whether the water supply differential pressure value of the main pipe is within a set safety range interval or not is judged; if yes, steam drum water level information is monitored in real time; if not, switching to a frequency converter pressure control mode, and dynamically adjusting the feed water pressure; according to the high-pressure and medium-pressure steam drum water level adjusting system, water supply modes are rapidly switched under different load conditions, so that the high-pressure and medium-pressure steam drum water level adjusting system of the unit adapts to various working conditions of frequent starting and stopping, and the working efficiency is improved. And the energy-saving loss is reduced as much as possible.

Description

Technical Field

[0001] The present application relates to the technical field of boiler feed water control, and in particular to a waste heat boiler feed water control method, system and medium. Background Art

[0002] At present, the feedwater control strategy of our waste heat boiler is single impulse control, the feedwater inverter controls the outlet pressure, and the feedwater regulating valve controls the drum water level. Since the capacity and range of the high-pressure feedwater pump configured in the system have a large margin, the unit is in peak operation, the high-pressure drum water level regulating valve is not opened enough, the throttling loss of the feedwater regulating valve is too large, and it is easy to wash the door core, resulting in a high failure rate. In addition, if the speed of the high-pressure feedwater pump is too low or too high, it deviates from the designed high-efficiency speed area, which affects the economic operation of the unit to a certain extent or causes vibration of the feedwater pipeline due to excessive output. Summary of the invention

[0003] The purpose of the embodiments of the present application is to provide a waste heat boiler feed water control method, system and medium, which can quickly switch the feed water mode under different load conditions to enable the high and medium pressure drum water level regulation system of the unit to adapt to various frequent start and shutdown conditions, ensure that the feed water main pipe pressure is as low as possible to reduce energy saving losses.

[0004] The embodiment of the present application also provides a waste heat boiler feed water control method, comprising:

[0005] Obtain turbine operating condition information and analyze turbine operating load based on the turbine operating condition information;

[0006] Select the matching feedwater control mode based on the turbine operating load, obtain the inlet and outlet feedwater pressure values ​​of the main pipe in real time, and calculate the main pipe feedwater differential pressure value;

[0007] Determine whether the main pipe water supply differential pressure value is within the set safety range;

[0008] If it is within the set safety range, the drum water level information is monitored in real time;

[0009] If it is not within the set safety range, it will switch to the inverter pressure control mode to dynamically adjust the water supply pressure.

[0010] Optionally, in the waste heat boiler feed water control method described in the embodiment of the present application, obtaining the steam turbine operating condition information, and analyzing the steam turbine operating load based on the steam turbine operating condition information includes:

[0011] Obtain the water level of the high-pressure drum variable frequency pump, the water level of the medium-pressure drum variable frequency pump, the pressure of the high-pressure drum feed water regulating valve, and the pressure of the medium-pressure drum feed water regulating valve to analyze the turbine operating load;

[0012] The steam turbine operating load is divided into levels based on the high, medium and low load division limits, and the level of the current steam turbine load is generated to obtain high load condition, medium load condition and low load condition.

[0013] Optionally, in the waste heat boiler feed water control method described in the embodiment of the present application, selecting a matching feed water control mode based on the steam turbine operating load specifically includes:

[0014] Set the steam turbine load and high-pressure feedwater pressure set value function to generate the high-pressure feedwater pressure set value that matches the steam turbine load;

[0015] Based on the high-pressure water supply pressure setting value matching water supply control mode, the water supply control mode includes the pump frequency conversion in the high-pressure water supply pressure control mode and the water supply regulating valve in the single impulse water level regulation mode; the pump frequency conversion in the high-pressure water supply pressure control mode and the water supply regulating valve in the three-impulse water level regulation mode; the pump frequency conversion in the three-impulse water level regulation and the water supply regulating valve in the high-pressure water supply pressure control mode;

[0016] Obtain the main steam flow of the steam turbine. If the main steam flow of the steam turbine is less than 68t / h, the turbine load is determined to be in low load condition, and the feedwater mode is matched to the high-pressure feedwater pressure control mode of the feedwater pump frequency conversion and the feedwater regulating valve in the single impulse water level regulation mode;

[0017] If the main steam flow of the steam turbine is greater than 103t / h and less than 240t / h, the turbine load is determined to be medium load condition, the feedwater mode matches the feed pump frequency conversion in the high-pressure feedwater pressure control mode and the feedwater regulating valve is in the three-impulse water level regulation mode;

[0018] If the main steam flow of the steam turbine is greater than 240t / h, the steam turbine load is determined to be in a high load condition, and the feed water mode matches the feed pump frequency conversion in three-impulse water level regulation and the feed water regulating valve is in high-pressure feed water pressure control mode.

[0019] Optionally, in the waste heat boiler feed water control method described in the embodiment of the present application, switching to the inverter pressure control mode specifically includes:

[0020] Obtain the high-pressure pump outlet pressure and the drum pressure, calculate the pressure difference, and obtain the main pipe feed water differential pressure value;

[0021] Analyze whether the main pipe water supply differential pressure value is within the set safety range;

[0022] When the difference between the high-pressure pump outlet pressure and the drum pressure is lower than 0.5Mpa, and the drum water level is not higher than 100mm, the frequency reduction of the variable frequency pump will be locked;

[0023] When the main steam flow rate is lower than 235t / h, it will switch to the inverter pressure control mode.

[0024] Optionally, in the waste heat boiler feed water control method described in the embodiment of the present application, switching to the inverter pressure control mode also includes:

[0025] Obtain the outlet pressure of the medium-pressure pump and the drum pressure, calculate the pressure difference, and obtain the main pipe feed water differential pressure value;

[0026] Analyze whether the main pipe water supply differential pressure value is within the set safety range;

[0027] When the outlet pressure of the medium pressure pump is lower than 4.3Mpa and the drum water level is not higher than 100mm, the frequency of the variable frequency pump is locked and reduced;

[0028] When the main steam flow rate is lower than 235t / h, it will switch to the inverter pressure control mode.

[0029] Optionally, in the waste heat boiler feed water control method described in the embodiment of the present application, real-time monitoring of drum water level information further includes:

[0030] Real-time monitoring of drum water level information based on water level control mode;

[0031] Obtain the operating status of the steam turbine, high-pressure drum feedwater variable frequency pump and medium-pressure drum feedwater variable frequency pump, and analyze whether the steam turbine, high-pressure drum feedwater variable frequency pump and medium-pressure drum feedwater variable frequency pump have tripped;

[0032] If the steam turbine or high-pressure drum feedwater variable frequency pump or medium-pressure drum feedwater variable frequency pump trips and connects the power frequency pump;

[0033] Based on the drum water level information, the drum water level set value is reduced by 50mm, and the water level control mode is switched to the feed water regulating valve water level maintenance mode, the variable frequency pump high-pressure feed water pressure mode, or the variable frequency pump medium-pressure feed water pressure mode to maintain the drum water level stable.

[0034] In a second aspect, an embodiment of the present application provides a waste heat boiler feed water control system, the system comprising: a memory and a processor, the memory comprising a program of a waste heat boiler feed water control method, and the program of the waste heat boiler feed water control method is executed by the processor to implement the following steps:

[0035] Obtain turbine operating condition information and analyze turbine operating load based on the turbine operating condition information;

[0036] Select the matching feedwater control mode based on the turbine operating load, obtain the inlet and outlet feedwater pressure values ​​of the main pipe in real time, and calculate the main pipe feedwater differential pressure value;

[0037] Determine whether the main pipe water supply differential pressure value is within the set safety range;

[0038] If it is within the set safety range, the drum water level information is monitored in real time;

[0039] If it is not within the set safety range, it will switch to the inverter pressure control mode to dynamically adjust the water supply pressure.

[0040] Optionally, in the waste heat boiler feed water control system described in the embodiment of the present application, obtaining the steam turbine operating condition information, and analyzing the steam turbine operating load based on the steam turbine operating condition information includes:

[0041] Obtain the water level of the high-pressure drum variable frequency pump, the water level of the medium-pressure drum variable frequency pump, the pressure of the high-pressure drum feed water regulating valve, and the pressure of the medium-pressure drum feed water regulating valve to analyze the turbine operating load;

[0042] The steam turbine operating load is divided into levels based on the high, medium and low load division limits, and the level of the current steam turbine load is generated to obtain high load condition, medium load condition and low load condition.

[0043] Optionally, in the waste heat boiler feed water control system described in the embodiment of the present application, selecting a matching feed water control mode based on the steam turbine operating load specifically includes:

[0044] Set the steam turbine load and high-pressure feedwater pressure set value function to generate the high-pressure feedwater pressure set value that matches the steam turbine load;

[0045] Based on the high-pressure water supply pressure setting value matching water supply control mode, the water supply control mode includes the pump frequency conversion in the high-pressure water supply pressure control mode and the water supply regulating valve in the single impulse water level regulation mode; the pump frequency conversion in the high-pressure water supply pressure control mode and the water supply regulating valve in the three-impulse water level regulation mode; the pump frequency conversion in the three-impulse water level regulation and the water supply regulating valve in the high-pressure water supply pressure control mode;

[0046] Obtain the main steam flow of the steam turbine. If the main steam flow of the steam turbine is less than 68t / h, the turbine load is determined to be in low load condition, and the feedwater mode is matched to the high-pressure feedwater pressure control mode of the feedwater pump frequency conversion and the feedwater regulating valve in the single impulse water level regulation mode;

[0047] If the main steam flow of the steam turbine is greater than 103t / h and less than 240t / h, the turbine load is determined to be medium load, the feedwater mode matches the feed pump frequency conversion in the high-pressure feedwater pressure control mode, and the feedwater regulating valve is in the three-impulse water level regulation mode;

[0048] If the main steam flow of the steam turbine is greater than 240t / h, the steam turbine load is determined to be in a high load condition, the feed water mode matches the feed pump frequency conversion in three-impulse water level regulation, and the feed water regulating valve is in high-pressure feed water pressure control mode.

[0049] In a third aspect, an embodiment of the present application further provides a computer-readable storage medium, wherein the computer-readable storage medium includes a waste heat boiler feed water control method program, and when the waste heat boiler feed water control method program is executed by a processor, the steps of the waste heat boiler feed water control method as described in any one of the above items are implemented.

[0050] As can be seen from the above, a waste heat boiler feed water control method, system and medium provided in an embodiment of the present application obtains the turbine operating condition information, analyzes the turbine operating load based on the turbine operating condition information; selects a matching feed water control mode based on the turbine operating load, and obtains the inlet feed water pressure value and the outlet feed water pressure value of the mother pipe in real time, and calculates the mother pipe feed water differential pressure value; determines whether the mother pipe feed water differential pressure value is within a set safety range; if it is within the set safety range, monitors the drum water level information in real time; if it is not within the set safety range, switches to the inverter pressure control mode and dynamically adjusts the feed water pressure; uses a three-impulse feed water variable frequency pump to adjust the water level under high load, so as to achieve the effect of variable frequency adjustment of the feed water pump water level and achieve energy-saving and consumption-reducing operation. The present application quickly switches the feed water mode under different load conditions, so that the high and medium pressure drum water level regulation systems of the unit can adapt to various conditions with frequent start and shutdown, and ensure that the mother water feed pipe pressure is as low as possible to reduce energy-saving losses. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0052] Figure 1 A flow chart of a waste heat boiler feed water control method provided in an embodiment of the present application;

[0053] Figure 2 A flow chart of steam turbine operation load analysis of a waste heat boiler feed water control method provided in an embodiment of the present application;

[0054] Figure 3 A flow chart of switching water supply control modes of a waste heat boiler water supply control method provided in an embodiment of the present application;

[0055] Figure 4 A relationship table between the turbine load and the feed water pressure setting value of the waste heat boiler feed water control method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0056] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

[0057] It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. At the same time, in the description of this application, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0058] Please refer to Figure 1 , Figure 1 This is a flow chart of a waste heat boiler feed water control method in some embodiments of the present application. The waste heat boiler feed water control method is used in a terminal device, and the waste heat boiler feed water control method includes the following steps:

[0059] S101, obtaining turbine operating condition information, and analyzing turbine operating load based on the turbine operating condition information;

[0060] S102, selecting a matching feedwater control mode based on the turbine operating load, obtaining the inlet feedwater pressure value and the outlet feedwater pressure value of the main pipe in real time, and calculating the main pipe feedwater differential pressure value;

[0061] S103, determining whether the main pipe water supply differential pressure value is within a set safety range;

[0062] S104, if it is within the set safety range, monitor the drum water level information in real time;

[0063] S105: If it is not within the set safety range, switch to the inverter pressure control mode to dynamically adjust the water supply pressure.

[0064] It should be noted that the three-impulse loop control logic of the inverter water level control is added to the high-pressure steam drum water level control regulation loop and the medium-pressure steam drum water level control regulation loop, which is used to adjust the water level of the variable frequency pump under high-load conditions of the unit, and to achieve disturbance-free switching and tracking with the original logic control method. The high-pressure feed water pressure control loop logic and the medium-pressure feed water pressure control loop logic are added to the feed water regulating valve control loop. When the variable frequency pump adjusts the steam drum water level, the feed water regulating valve can achieve disturbance-free switching to control the high-pressure feed water pressure or the medium-pressure feed water pressure.

[0065] Please refer to Figure 2 , Figure 2 It is a flow chart of turbine operation load analysis of a waste heat boiler feed water control method in some embodiments of the present application. According to an embodiment of the present invention, obtaining turbine operation condition information, and analyzing the turbine operation load based on the turbine operation condition information include:

[0066] S201, obtaining the water level of the high-pressure drum variable frequency pump, the water level of the medium-pressure drum variable frequency pump, the pressure of the high-pressure drum feed water regulating valve, and the pressure of the medium-pressure drum feed water regulating valve, and analyzing the steam turbine operating load;

[0067] S202, classifying the steam turbine operating load into levels based on the high, medium and low load classification limits, generating the level of the current steam turbine load, and obtaining high load condition, medium load condition and low load condition.

[0068] Please refer to Figure 3 , Figure 3 This is a flow chart of switching water supply control modes of a waste heat boiler water supply control method in some embodiments of the present application. According to an embodiment of the present invention, selecting a matching water supply control mode based on the steam turbine operating load specifically includes:

[0069] S301, setting a function of a steam turbine load and a high-pressure feedwater pressure setting value to generate a high-pressure feedwater pressure setting value that matches the steam turbine load;

[0070] S302, matching the water supply control mode based on the high-pressure water supply pressure setting value, the water supply control mode includes the pump frequency conversion in the high-pressure water supply pressure control mode and the water supply regulating valve in the single-impulse water level regulation mode; the pump frequency conversion in the high-pressure water supply pressure control mode and the water supply regulating valve in the three-impulse water level regulation mode; the pump frequency conversion in the three-impulse water level regulation and the water supply regulating valve in the high-pressure water supply pressure control mode;

[0071] S303, obtaining the main steam flow of the steam turbine. If the main steam flow of the steam turbine is less than 68 t / h, it is determined that the steam turbine load is in a low load condition, the feedwater mode is matched, the feedwater pump frequency conversion is in a high-pressure feedwater pressure control mode, and the feedwater regulating valve is in a single impulse water level regulation mode;

[0072] S304, if the main steam flow of the steam turbine is greater than 103 t / h and less than 240 t / h, it is determined that the steam turbine load is in medium load condition, the feedwater mode matches the feed pump frequency conversion in the high-pressure feedwater pressure control mode and the feedwater regulating valve is in the three-impulse water level regulation mode;

[0073] S305, if the main steam flow of the steam turbine is greater than 240t / h, it is determined that the steam turbine load is in a high load condition, and the feed water mode matches the feed pump frequency conversion in three-impulse water level regulation and the feed water regulating valve is in high-pressure feed water pressure control mode.

[0074] According to an embodiment of the present invention, switching to the frequency converter pressure control mode specifically includes:

[0075] Obtain the high-pressure pump outlet pressure and the drum pressure, calculate the pressure difference, and obtain the main pipe feed water differential pressure value;

[0076] Analyze whether the main pipe water supply differential pressure value is within the set safety range;

[0077] When the difference between the high-pressure pump outlet pressure and the drum pressure is lower than 0.5Mpa, and the drum water level is not higher than 100mm, the frequency reduction of the variable frequency pump will be locked;

[0078] When the main steam flow rate is lower than 235t / h, it will switch to the inverter pressure control mode.

[0079] According to an embodiment of the present invention, switching to the frequency converter pressure control mode also includes:

[0080] Obtain the outlet pressure of the medium-pressure pump and the drum pressure, calculate the pressure difference, and obtain the main pipe feed water differential pressure value;

[0081] Analyze whether the main pipe water supply differential pressure value is within the set safety range;

[0082] When the outlet pressure of the medium pressure pump is lower than 4.3Mpa and the drum water level is not higher than 100mm, the frequency of the variable frequency pump is locked and reduced;

[0083] When the main steam flow rate is lower than 235t / h, it will switch to the inverter pressure control mode.

[0084] According to an embodiment of the present invention, real-time monitoring of drum water level information also includes:

[0085] Real-time monitoring of drum water level information based on water level control mode;

[0086] Obtain the operating status of the steam turbine, high-pressure drum feedwater variable frequency pump and medium-pressure drum feedwater variable frequency pump, and analyze whether the steam turbine, high-pressure drum feedwater variable frequency pump and medium-pressure drum feedwater variable frequency pump have tripped;

[0087] If the steam turbine or high-pressure drum feedwater variable frequency pump or medium-pressure drum feedwater variable frequency pump trips and connects the power frequency pump;

[0088] Based on the drum water level information, the drum water level set value is reduced by 50mm, and the water level control mode is switched to the feed water regulating valve water level maintenance mode, the variable frequency pump high-pressure feed water pressure mode, or the variable frequency pump medium-pressure feed water pressure mode to maintain the drum water level stable.

[0089] It should be noted that if a steam turbine trip occurs suddenly or the high-pressure drum feedwater variable frequency pump trips and connects to the industrial frequency pump, the water level control mode will immediately switch to the mode in which the feedwater regulating valve maintains the water level and the variable frequency pump adjusts the high-pressure feedwater pressure. In order to ensure large bypass water flow, the logic is designed to reduce the drum water level set value by 50mm at a certain rate after the trip signal is sent, in order to maintain the drum water level under the trip condition without excessive fluctuations, to ensure normal drum water level.

[0090] Please refer to Figure 4 , Figure 4 It is a relationship table between the steam turbine load and the feed water pressure setting value of a waste heat boiler feed water control method in some embodiments of the present application. According to an embodiment of the present invention, it also includes:

[0091] Obtain turbine operating condition information, and analyze the current turbine load based on the turbine operating condition information; set turbine load and feedwater pressure set value function, and analyze the feedwater pressure set value that matches the current turbine load according to the turbine load and feedwater pressure set value function; set adjustment parameters through the three-impulse loop control logic of the inverter water level control according to the feedwater pressure set value, and adjust the variable frequency pump water level of the unit based on the adjustment parameters; perform unit load increase and decrease tests based on turbine operating condition information, and obtain mother pipe pressure information in real time; dynamically adjust adjustment parameters based on mother pipe pressure information.

[0092] It should be noted that the functional relationship between the various openings and loads of the feedwater regulating valve under high-load conditions is determined through experiments to ensure that the pressure of the feedwater main pipe is as low as possible to reduce energy-saving losses, thereby saving energy and meeting the normal pressure of each main pipe user (such as high- and medium-pressure superheated steam desuperheating water). The unit load increase and decrease test is carried out, and the relevant subsystem parameters after the new strategy are adjusted to enable the feedwater control system to meet the unit's needs for rapid load increase and decrease.

[0093] In a second aspect, an embodiment of the present application provides a waste heat boiler feed water control system, the system comprising: a memory and a processor, the memory comprising a program of a waste heat boiler feed water control method, and when the program of the waste heat boiler feed water control method is executed by the processor, the following steps are implemented:

[0094] Obtain turbine operating condition information and analyze turbine operating load based on the turbine operating condition information;

[0095] Select the matching feedwater control mode based on the turbine operating load, obtain the inlet and outlet feedwater pressure values ​​of the main pipe in real time, and calculate the main pipe feedwater differential pressure value;

[0096] Determine whether the main pipe water supply differential pressure value is within the set safety range;

[0097] If it is within the set safety range, the drum water level information is monitored in real time;

[0098] If it is not within the set safety range, it will switch to the inverter pressure control mode to dynamically adjust the water supply pressure.

[0099] It should be noted that the three-impulse loop control logic of the inverter water level control is added to the high-pressure steam drum water level control regulation loop and the medium-pressure steam drum water level control regulation loop, which is used to adjust the water level of the variable frequency pump under high-load conditions of the unit, and to achieve disturbance-free switching and tracking with the original logic control method. The high-pressure feed water pressure control loop logic and the medium-pressure feed water pressure control loop logic are added to the feed water regulating valve control loop. When the variable frequency pump adjusts the steam drum water level, the feed water regulating valve can achieve disturbance-free switching to control the high-pressure feed water pressure or the medium-pressure feed water pressure.

[0100] According to an embodiment of the present invention, obtaining turbine operating condition information and analyzing turbine operating load based on the turbine operating condition information includes:

[0101] Obtain the water level of the high-pressure drum variable frequency pump, the water level of the medium-pressure drum variable frequency pump, the pressure of the high-pressure drum feed water regulating valve, and the pressure of the medium-pressure drum feed water regulating valve to analyze the turbine operating load;

[0102] The steam turbine operating load is divided into levels based on the high, medium and low load division limits, and the level of the current steam turbine load is generated to obtain high load condition, medium load condition and low load condition.

[0103] According to an embodiment of the present invention, selecting a matching feedwater control mode based on the turbine operating load specifically includes:

[0104] Set the steam turbine load and high-pressure feedwater pressure set value function to generate the high-pressure feedwater pressure set value that matches the steam turbine load;

[0105] Based on the high-pressure water supply pressure setting value matching water supply control mode, the water supply control mode includes the pump frequency conversion in the high-pressure water supply pressure control mode and the water supply regulating valve in the single-impulse water level regulation mode; the pump frequency conversion in the high-pressure water supply pressure control mode and the water supply regulating valve in the three-impulse water level regulation mode; the pump frequency conversion in the three-impulse water level regulation and the water supply regulating valve in the high-pressure water supply pressure control mode;

[0106] Obtain the main steam flow of the steam turbine. If the main steam flow of the steam turbine is less than 68t / h, the turbine load is determined to be in low load condition, and the feedwater mode is matched to the high-pressure feedwater pressure control mode of the feedwater pump frequency conversion and the feedwater regulating valve in the single impulse water level regulation mode;

[0107] If the main steam flow of the steam turbine is greater than 103t / h and less than 240t / h, the turbine load is determined to be medium load, the feedwater mode matches the feed pump frequency conversion in the high-pressure feedwater pressure control mode, and the feedwater regulating valve is in the three-impulse water level regulation mode;

[0108] If the main steam flow of the steam turbine is greater than 240t / h, the steam turbine load is determined to be in a high load condition, the feed water mode matches the feed pump frequency conversion in three-impulse water level regulation, and the feed water regulating valve is in high-pressure feed water pressure control mode.

[0109] According to an embodiment of the present invention, switching to the frequency converter pressure control mode specifically includes:

[0110] Obtain the high-pressure pump outlet pressure and the drum pressure, calculate the pressure difference, and obtain the main pipe feed water differential pressure value;

[0111] Analyze whether the main pipe water supply differential pressure value is within the set safety range;

[0112] When the difference between the high-pressure pump outlet pressure and the drum pressure is lower than 0.5Mpa, and the drum water level is not higher than 100mm, the frequency reduction of the variable frequency pump will be locked;

[0113] When the main steam flow rate is lower than 235t / h, it will switch to the inverter pressure control mode.

[0114] According to an embodiment of the present invention, switching to the frequency converter pressure control mode also includes:

[0115] Obtain the outlet pressure of the medium-pressure pump and the drum pressure, calculate the pressure difference, and obtain the main pipe feed water differential pressure value;

[0116] Analyze whether the main pipe water supply differential pressure value is within the set safety range;

[0117] When the outlet pressure of the medium pressure pump is lower than 4.3Mpa and the drum water level is not higher than 100mm, the frequency of the variable frequency pump is locked and reduced;

[0118] When the main steam flow rate is lower than 235t / h, it will switch to the inverter pressure control mode.

[0119] According to an embodiment of the present invention, real-time monitoring of drum water level information also includes:

[0120] Real-time monitoring of drum water level information based on water level control mode;

[0121] Obtain the operating status of the steam turbine, high-pressure drum feedwater variable frequency pump and medium-pressure drum feedwater variable frequency pump, and analyze whether the steam turbine, high-pressure drum feedwater variable frequency pump and medium-pressure drum feedwater variable frequency pump have tripped;

[0122] If the steam turbine or high-pressure drum feedwater variable frequency pump or medium-pressure drum feedwater variable frequency pump trips and connects the power frequency pump;

[0123] Based on the drum water level information, the drum water level set value is reduced by 50mm, and the water level control mode is switched to the feed water regulating valve water level maintenance mode, the variable frequency pump high-pressure feed water pressure mode, or the variable frequency pump medium-pressure feed water pressure mode to maintain the drum water level stable.

[0124] It should be noted that if a steam turbine trip occurs suddenly or the high-pressure drum feedwater variable frequency pump trips and connects to the industrial frequency pump, the water level control mode will immediately switch to the mode in which the feedwater regulating valve maintains the water level and the variable frequency pump adjusts the high-pressure feedwater pressure. In order to ensure large bypass water flow, the logic is designed to reduce the drum water level set value by 50mm at a certain rate after the trip signal is sent, in order to maintain the drum water level under the trip condition without excessive fluctuations, to ensure normal drum water level.

[0125] According to an embodiment of the present invention, it also includes:

[0126] Obtain turbine operating condition information, and analyze the current turbine load based on the turbine operating condition information; set turbine load and feedwater pressure set value function, and analyze the feedwater pressure set value that matches the current turbine load according to the turbine load and feedwater pressure set value function; set adjustment parameters through the three-impulse loop control logic of the inverter water level control according to the feedwater pressure set value, and adjust the variable frequency pump water level of the unit based on the adjustment parameters; perform unit load increase and decrease tests based on turbine operating condition information, and obtain mother pipe pressure information in real time; dynamically adjust adjustment parameters based on mother pipe pressure information.

[0127] It should be noted that the functional relationship between the various openings and loads of the feedwater regulating valve under high-load conditions is determined through experiments to ensure that the pressure of the feedwater main pipe is as low as possible to reduce energy-saving losses, thereby saving energy and meeting the normal pressure of each main pipe user (such as high- and medium-pressure superheated steam desuperheating water). The unit load increase and decrease test is carried out, and the relevant subsystem parameters after the new strategy are adjusted to enable the feedwater control system to meet the unit's needs for rapid load increase and decrease.

[0128] A third aspect of the present invention provides a computer-readable storage medium, which includes a waste heat boiler feed water control method program. When the waste heat boiler feed water control method program is executed by a processor, the steps of any of the waste heat boiler feed water control methods described above are implemented.

[0129] The present invention discloses a waste heat boiler feed water control method, system and medium, which obtains the turbine operating condition information, analyzes the turbine operating load based on the turbine operating condition information; selects a matching feed water control mode based on the turbine operating load, and obtains the inlet feed water pressure value and the outlet feed water pressure value of the mother pipe in real time, and calculates the mother pipe feed water differential pressure value; determines whether the mother pipe feed water differential pressure value is within a set safety range; if it is within the set safety range, monitors the drum water level information in real time; if it is not within the set safety range, switches to the inverter pressure control mode, and dynamically adjusts the feed water pressure; uses a three-impulse feed water variable frequency pump to adjust the water level under high load, so as to achieve the effect of variable frequency adjustment of the feed water pump water level and energy-saving and consumption-reducing operation. The present application performs rapid switching of feed water modes under different load conditions, so that the high and medium pressure drum water level regulation systems of the unit can adapt to various conditions with frequent start and shutdown, and ensure that the mother water feed pipe pressure is as low as possible to reduce energy-saving losses.

[0130] In the several embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are only schematic. For example, the division of units is only a logical function division. There may be other division methods in actual implementation, such as: multiple units or components can be combined, or can be integrated into another system, or some features can be ignored or not executed. In addition, the coupling, direct coupling, or communication connection between the components shown or discussed can be through some interfaces, and the indirect coupling or communication connection of devices or units can be electrical, mechanical or other forms.

[0131] The units described above as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units; they may be located in one place or distributed on multiple network units; some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0132] In addition, all functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may be separately used as a unit, or two or more units may be integrated into one unit; the above-mentioned integrated units may be implemented in the form of hardware or in the form of hardware plus software functional units.

[0133] Those skilled in the art can understand that: all or part of the steps of implementing the above method embodiments can be completed by hardware related to program instructions, the aforementioned program can be stored in a readable storage medium, and when the program is executed, it executes the steps of the above method embodiments; and the aforementioned storage medium includes: mobile storage devices, read-only memories (ROM, Read-Only Memory), random access memories (RAM, Random Access Memory), disks or optical disks, and other media that can store program codes.

[0134] Or, if the above-mentioned integrated unit of the present invention is implemented in the form of a software function module and sold or used as an independent product, it can also be stored in a readable storage medium. Based on this understanding, the technical solution of the embodiment of the present invention can be essentially or partly reflected in the form of a software product that contributes to the prior art. The software product is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the methods described in each embodiment of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as mobile storage devices, ROM, RAM, magnetic disks or optical disks.

Claims

1. A waste heat boiler feed water control method, characterized in that: include: Obtain turbine operating condition information and analyze turbine operating load based on the turbine operating condition information; Select the matching feedwater control mode based on the turbine operating load, obtain the inlet and outlet feedwater pressure values ​​of the main pipe in real time, and calculate the main pipe feedwater differential pressure value; Determine whether the main pipe water supply differential pressure value is within the set safety range; If it is within the set safety range, the drum water level information is monitored in real time; If it is not within the set safety range, it will switch to the inverter pressure control mode to dynamically adjust the water supply pressure.

2. The waste heat boiler feed water control method according to claim 1, characterized in that: Obtain turbine operating condition information and analyze turbine operating load based on the turbine operating condition information, including: Obtain the water level of the high-pressure drum variable frequency pump, the water level of the medium-pressure drum variable frequency pump, the pressure of the high-pressure drum feed water regulating valve, and the pressure of the medium-pressure drum feed water regulating valve to analyze the turbine operating load; The steam turbine operating load is divided into levels based on the high, medium and low load division limits, and the level of the current steam turbine load is generated to obtain high load condition, medium load condition and low load condition.

3. The waste heat boiler feed water control method according to claim 2, characterized in that: The feedwater control mode is selected based on the turbine operating load, including: Set the steam turbine load and high-pressure feedwater pressure set value function to generate the high-pressure feedwater pressure set value that matches the steam turbine load; Based on the high-pressure water supply pressure setting value matching water supply control mode, the water supply control mode includes the pump frequency conversion in the high-pressure water supply pressure control mode and the water supply regulating valve in the single impulse water level regulation mode; the pump frequency conversion in the high-pressure water supply pressure control mode and the water supply regulating valve in the three-impulse water level regulation mode; the pump frequency conversion in the three-impulse water level regulation and the water supply regulating valve in the high-pressure water supply pressure control mode; Obtain the main steam flow of the steam turbine. If the main steam flow of the steam turbine is less than 68t / h, the turbine load is determined to be in low load condition, and the feedwater mode is matched to the high-pressure feedwater pressure control mode of the feedwater pump frequency conversion and the feedwater regulating valve in the single impulse water level regulation mode; If the main steam flow of the steam turbine is greater than 103t / h and less than 240t / h, the turbine load is determined to be medium load condition, the feedwater mode matches the feed pump frequency conversion in the high-pressure feedwater pressure control mode and the feedwater regulating valve is in the three-impulse water level regulation mode; If the main steam flow of the steam turbine is greater than 240t / h, the steam turbine load is determined to be in a high load condition, and the feed water mode matches the feed pump frequency conversion in three-impulse water level regulation and the feed water regulating valve is in high-pressure feed water pressure control mode.

4. The waste heat boiler feed water control method according to claim 3, characterized in that: Switch to the inverter pressure control mode, including: Obtain the high-pressure pump outlet pressure and the drum pressure, calculate the pressure difference, and obtain the main pipe feed water differential pressure value; Analyze whether the main pipe water supply differential pressure value is within the set safety range; When the difference between the high-pressure pump outlet pressure and the drum pressure is lower than 0.5Mpa, and the drum water level is not higher than 100mm, the frequency reduction of the variable frequency pump will be locked; When the main steam flow rate is lower than 235t / h, it will switch to the inverter pressure control mode.

5. The waste heat boiler feed water control method according to claim 3, characterized in that: Switch to the inverter pressure control mode, which also includes: Obtain the outlet pressure of the medium-pressure pump and the drum pressure, calculate the pressure difference, and obtain the main pipe feed water differential pressure value; Analyze whether the main pipe water supply differential pressure value is within the set safety range; When the outlet pressure of the medium pressure pump is lower than 4.3Mpa and the drum water level is not higher than 100mm, the frequency of the variable frequency pump is locked and reduced; When the main steam flow rate is lower than 235t / h, it will switch to the inverter pressure control mode.

6. The waste heat boiler feed water control method according to claim 1, characterized in that: Real-time monitoring of drum water level information, including: Real-time monitoring of drum water level information based on water level control mode; Obtain the operating status of the steam turbine, high-pressure drum feedwater variable frequency pump and medium-pressure drum feedwater variable frequency pump, and analyze whether the steam turbine, high-pressure drum feedwater variable frequency pump and medium-pressure drum feedwater variable frequency pump have tripped; If the steam turbine or high-pressure drum feedwater variable frequency pump or medium-pressure drum feedwater variable frequency pump trips and connects the power frequency pump; Based on the drum water level information, the drum water level set value is reduced by 50mm, and the water level control mode is switched to the feed water regulating valve water level maintenance mode, the variable frequency pump high-pressure feed water pressure mode, or the variable frequency pump medium-pressure feed water pressure mode to maintain the drum water level stable.

7. A waste heat boiler feed water control system, characterized in that: The system includes: a memory and a processor, wherein the memory includes a program of a waste heat boiler feed water control method, and when the program of the waste heat boiler feed water control method is executed by the processor, the following steps are implemented: Obtain turbine operating condition information and analyze turbine operating load based on the turbine operating condition information; Select the matching feedwater control mode based on the turbine operating load, obtain the inlet and outlet feedwater pressure values ​​of the main pipe in real time, and calculate the main pipe feedwater differential pressure value; Determine whether the main pipe water supply differential pressure value is within the set safety range; If it is within the set safety range, the drum water level information is monitored in real time; If it is not within the set safety range, it will switch to the inverter pressure control mode to dynamically adjust the water supply pressure.

8. The waste heat boiler feed water control system according to claim 7, characterized in that: Obtain turbine operating condition information and analyze turbine operating load based on the turbine operating condition information, including: Obtain the water level of the high-pressure drum variable frequency pump, the water level of the medium-pressure drum variable frequency pump, the pressure of the high-pressure drum feed water regulating valve, and the pressure of the medium-pressure drum feed water regulating valve to analyze the turbine operating load; The steam turbine operating load is divided into levels based on the high, medium and low load division limits, and the level of the current steam turbine load is generated to obtain high load condition, medium load condition and low load condition.

9. The waste heat boiler feed water control system according to claim 8, characterized in that: The feedwater control mode is selected based on the turbine operating load, including: Set the steam turbine load and high-pressure feedwater pressure set value function to generate the high-pressure feedwater pressure set value that matches the steam turbine load; Based on the high-pressure water supply pressure setting value matching water supply control mode, the water supply control mode includes the pump frequency conversion in the high-pressure water supply pressure control mode and the water supply regulating valve in the single impulse water level regulation mode; the pump frequency conversion in the high-pressure water supply pressure control mode and the water supply regulating valve in the three-impulse water level regulation mode; the pump frequency conversion in the three-impulse water level regulation and the water supply regulating valve in the high-pressure water supply pressure control mode; Obtain the main steam flow of the steam turbine. If the main steam flow of the steam turbine is less than 68t / h, the turbine load is determined to be in low load condition, and the feedwater mode is matched to the high-pressure feedwater pressure control mode of the feedwater pump frequency conversion and the feedwater regulating valve in the single impulse water level regulation mode; If the main steam flow of the steam turbine is greater than 103t / h and less than 240t / h, the turbine load is determined to be medium load, the feedwater mode matches the feed pump frequency conversion in the high-pressure feedwater pressure control mode, and the feedwater regulating valve is in the three-impulse water level regulation mode; If the main steam flow of the steam turbine is greater than 240t / h, the steam turbine load is determined to be in a high load condition, the feed water mode matches the feed pump frequency conversion in three-impulse water level regulation, and the feed water regulating valve is in high-pressure feed water pressure control mode.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium includes a waste heat boiler feed water control method program, and when the waste heat boiler feed water control method program is executed by a processor, the steps of the waste heat boiler feed water control method according to any one of claims 1 to 6 are implemented.

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