CN114607632A - Method, system and device for operating induced draft fan of thermal generator set - Google Patents

Method, system and device for operating induced draft fan of thermal generator set Download PDF

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Publication number
CN114607632A
CN114607632A CN202210284821.7A CN202210284821A CN114607632A CN 114607632 A CN114607632 A CN 114607632A CN 202210284821 A CN202210284821 A CN 202210284821A CN 114607632 A CN114607632 A CN 114607632A
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CN
China
Prior art keywords
induced draft
draft fan
pneumatic
fan
control strategy
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CN202210284821.7A
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Chinese (zh)
Inventor
张桂彬
易晓坚
邹毅辉
陈超
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China Energy Engineering Group Central China Electric Power Test Research Institute Co ltd
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China Energy Engineering Group Central China Electric Power Test Research Institute Co ltd
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Priority to CN202210284821.7A priority Critical patent/CN114607632A/en
Publication of CN114607632A publication Critical patent/CN114607632A/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D27/00—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D27/00—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids
    • F04D27/002—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids by varying geometry within the pumps, e.g. by adjusting vanes
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D27/00—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids
    • F04D27/004—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids by varying driving speed
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N3/00—Regulating air supply or draught
    • F23N3/005—Regulating air supply or draught using electrical or electromechanical means

Abstract

A method, a system and a device for operating a thermal generator set induced draft fan are provided, the method for operating the thermal generator set induced draft fan comprises the following steps: acquiring unit load of a thermal generator set; selecting an operation control strategy for the induced draft fan set according to the load of the unit; the first pneumatic draught fan can be arranged in parallel when the electric draught fan operates through a first parallel control strategy, the electric draught fan is arranged in parallel, and the negative pressure of the hearth is stable, so that the electric draught fan is switched to the first pneumatic draught fan. And a second parallel control strategy is adopted to enable a second pneumatic draught fan to be parallel to the first pneumatic draught fan when the first pneumatic draught fan runs so as to match the raised unit load. The third parallel control strategy can be used for paralleling the electric induced draft fans when the first pneumatic induced draft fan runs so as to match the reduced unit load, and the problems of low running stability, low energy-saving running efficiency and high energy consumption of the existing induced draft fan unit under the low-load working condition are solved.

Description

Method, system and device for operating induced draft fan of thermal generator set
Technical Field
The invention belongs to the field of thermal power generation, and particularly relates to a method, a system and a device for operating a thermal generator set induced draft fan.
Background
Along with the implementation of the ultra-low emission policy of the thermal generator set and the gradual increase of the capacity of the existing newly-built thermal generator set, the number of tail flue devices of the boiler is increased, the on-way resistance is increased, and the electric capacity of the induced draft fan is also gradually increased. The pressure drop of an induced draft system of a boiler is mainly dynamic pressure, the pressure head selection of an induced draft fan is too large, and the boiler can be seriously deviated from the optimal efficiency point under the working condition of maximum continuous evaporation capacity (MCR) of the boiler in practice, so that the energy consumption loss of the induced draft fan is caused, the operation efficiency is low, the operation stability of the existing induced draft fan operation method and operation system under the low-load working condition is low, the energy-saving operation efficiency is low, and the purpose of saving energy cannot be effectively achieved.
Disclosure of Invention
The present invention is directed to solving at least one of the problems of the prior art. Therefore, the invention provides a method for operating a thermal generator set induced draft fan, which solves the problems of low operation stability, low energy-saving operation efficiency and high energy consumption of the existing method and system for operating the induced draft fan under the low-load working condition.
The invention also provides a thermal generator set induced draft fan operation system and a thermal generator set induced draft fan operation device.
According to the first aspect of the invention, the method for operating the induced draft fan of the thermal generator set comprises the following steps:
acquiring unit load of a thermal generator set;
selecting an operation control strategy for the induced draft fan set according to the unit load; the operation control strategy comprises a first parallel control strategy, a second parallel control strategy and a third parallel control strategy; the induced draft fan set comprises an electric induced draft fan, a first pneumatic induced draft fan and a second pneumatic induced draft fan;
wherein the first parallel control strategy comprises the steps of: adjusting the negative pressure of the hearth to be within a preset stable range through the electric induced draft fan, and performing parallel operation on the first pneumatic induced draft fan; adjusting the stationary blade opening degree of the electric induced draft fan and the rotating speed and/or the stationary blade opening degree of the first pneumatic induced draft fan until the stationary blade opening degree of the electric induced draft fan is in a full-closed state, and closing the electric induced draft fan;
the second coordinated control strategy comprises the steps of: adjusting the negative pressure of the hearth to be within the preset stable range through the first pneumatic induced draft fan, and performing parallel operation on the second pneumatic induced draft fan; adjusting the rotating speed and/or the stationary blade opening of the first and second pneumatic draught fans until the rotating speed and the stationary blade opening of the first and second pneumatic draught fans are the same;
the third coordinated control strategy comprises the steps of: adjusting the negative pressure of the hearth to be within the preset stable range through the first pneumatic induced draft fan, and performing parallel operation on the electric induced draft fans; and adjusting the stationary blade opening degree of the electric induced draft fan and the first pneumatic induced draft fan until the negative pressure of the hearth is in the preset stable range.
The method for operating the induced draft fan of the thermal generator set provided by the embodiment of the invention at least has the following technical effects: after the unit load of the thermal generator set is obtained, the operation control strategy of the induced draft fan set can be selected according to the unit load. The first parallel control strategy can be used for parallelly controlling the first pneumatic draught fans when the electric draught fans operate, the electric draught fans are parallelly completed, the negative pressure of the hearth is stable, and then the electric draught fans are closed, so that the electric draught fans are switched to the first pneumatic draught fans. And a second parallel control strategy is adopted to enable a second pneumatic draught fan to be parallel to the first pneumatic draught fan when the first pneumatic draught fan runs so as to match the raised unit load. And the electric induced draft fans can be arranged in parallel when the first pneumatic induced draft fan runs through a third parallel control strategy so as to match the reduced unit load. By executing the operation control strategy of the induced draft fan unit, the automatic switching of the electric induced draft fan, the first pneumatic induced draft fan and the second pneumatic induced draft fan under different unit loads can be realized, the first pneumatic induced draft fan can be put into use in advance, the low-load working condition is adapted, the energy consumption is reduced, the energy-saving operation efficiency is improved, and the problems of low operation stability, low energy-saving operation efficiency and high energy consumption of the existing induced draft fan operation method and operation system under the low-load working condition are solved.
According to some embodiments of the invention, the selecting an operation control strategy for the induced air unit according to the unit load comprises the following steps:
if the unit load is larger than a preset first switching load value, executing the first parallel control strategy on the induced draft fan unit;
if the unit load is larger than a preset second switching load value, executing the second parallel control strategy on the induced draft fan unit;
if the unit load is smaller than a preset third switching load value, executing a third parallel control strategy on the induced draft fan unit; the first handover load value is smaller than the third handover load value, and the third handover load value is smaller than the second handover load value.
According to some embodiments of the invention, the adjusting of the stationary blade opening of the electric induced draft fan and the rotation speed and/or the stationary blade opening of the first pneumatic induced draft fan comprises:
increasing the stator blade opening of the first pneumatic induced draft fan to the optimal stator blade opening position;
and increasing the rotating speed of the first pneumatic draught fan, reducing the static blade opening degree of the electric draught fan until the static blade opening degree of the electric draught fan is in a fully-closed state.
According to some embodiments of the invention, the boiler is ignited by the electrically induced draft fan when the boiler is started.
According to some embodiments of the invention, the first or second induced draft fan, in a start-up phase, performs the following steps:
adjusting an induced draft fan steam turbine corresponding to the first or second pneumatic induced draft fan to a preset minimum remote control rotation speed, and adjusting the negative pressure of the hearth to be within the preset stable range by adjusting the stationary blade opening of the first or second pneumatic induced draft fan;
adjusting the stationary blade opening of the first or second pneumatic draught fan to a preset stationary blade economic opening position according to the air volume of the boiler or the unit load, and adjusting the hearth negative pressure to be within the preset stable range by adjusting the rotating speed of a draught fan steam turbine corresponding to the first or second pneumatic draught fan;
adjusting the opening degree of the stationary blade of the first or second pneumatic induced draft fan to an opening degree preset value corresponding to the current unit load; the preset opening value is obtained by a fitting function between the opening of the stator blade and the load of the unit.
According to some embodiments of the invention, a supplementary burner or a plasma burner is introduced to stabilize the boiler before the first, second and third parallel control strategies are executed.
According to the second aspect of the invention, the system for operating the induced draft fan of the thermal generator set comprises:
the unit load acquisition unit is used for acquiring the unit load of the thermal generator set;
the control strategy selection unit is used for selecting an operation control strategy for the induced draft fan set according to the unit load; the operation control strategy comprises a first parallel control strategy, a second parallel control strategy and a third parallel control strategy; the induced draft fan set comprises an electric induced draft fan, a first pneumatic induced draft fan and a second pneumatic induced draft fan;
a first parallel operation control unit for executing the first parallel control strategy; the first parallel control strategy comprises the steps of: adjusting the negative pressure of the hearth to be within a preset stable range through the electric induced draft fan, and performing parallel operation on the first pneumatic induced draft fan; adjusting the stationary blade opening degree of the electric induced draft fan and the rotating speed and/or the stationary blade opening degree of the first pneumatic induced draft fan until the stationary blade opening degree of the electric induced draft fan is in a full-closed state, and closing the electric induced draft fan;
a second parallel operation control unit for executing the second parallel control strategy; the second coordinated control strategy comprises the steps of: adjusting the negative pressure of the hearth to be within the preset stable range through the first pneumatic induced draft fan, and performing parallel operation on the second pneumatic induced draft fan; adjusting the rotating speed and/or the stationary blade opening of the first and second pneumatic draught fans until the rotating speed and the stationary blade opening of the first and second pneumatic draught fans are the same;
a third parallel operation control unit for executing the third parallel control strategy; the third coordinated control strategy comprises the steps of: adjusting the negative pressure of the hearth to be within the preset stable range through the first pneumatic induced draft fan, and performing parallel operation on the electric induced draft fans; and adjusting the stationary blade opening degree of the electric induced draft fan and the first pneumatic induced draft fan until the negative pressure of the hearth is in the preset stable range.
The operation system of the induced draft fan of the thermal generator set provided by the embodiment of the invention at least has the following technical effects: the unit load of the thermal generator set can be obtained through the unit load obtaining unit, and the operation control strategy of the induced draft fan set can be selected through the control strategy selecting unit according to the unit load. The first parallel control strategy can be executed through the first parallel operation control unit, so that the first pneumatic draught fan is arranged in parallel when the electric draught fan operates, the electric draught fan is closed after parallel completion and the negative pressure of the hearth is stable, and switching from the electric draught fan to the first pneumatic draught fan is realized. And the second parallel operation control unit can execute a second parallel control strategy, so that the second pneumatic draught fan is parallel when the first pneumatic draught fan operates, and the raised unit load is matched. And the third parallel operation control unit can execute a third parallel control strategy, so that the electric induced draft fans are parallel when the first pneumatic induced draft fan runs, and the reduced unit load is matched. By executing the operation control strategy of the induced draft fan unit, the automatic switching of the electric induced draft fan, the first pneumatic induced draft fan and the second pneumatic induced draft fan under different unit loads can be realized, the first pneumatic induced draft fan can be put into use in advance, the low-load working condition is adapted, the energy consumption is reduced, the energy-saving operation efficiency is improved, and the problems of low operation stability, low energy-saving operation efficiency and high energy consumption of the existing induced draft fan operation method and operation system under the low-load working condition are solved.
According to the third aspect embodiment of the invention, the thermal generator set induced draft fan operation device comprises:
the induced draft fan unit comprises an electric induced draft fan, a first pneumatic induced draft fan and a second pneumatic induced draft fan; the draught fan set is used for exhausting steam generated by combustion of the boiler so as to maintain the pressure of the hearth;
the two steam-driven induced draft fans are connected with the first steam-driven induced draft fan and the second steam-driven induced draft fan in a one-to-one correspondence manner;
and the DCS is used for executing the operation method of the induced draft fan of the thermal generator set in the embodiment of the first aspect.
The operation device of the induced draft fan of the thermal generator set provided by the embodiment of the invention at least has the following technical effects: the DCS can realize automatic switching of the electric draught fan, the first pneumatic draught fan and the second pneumatic draught fan under different unit loads, the first pneumatic draught fan can be put into use in advance, the low-load working condition is adapted, the energy consumption is reduced, and the energy-saving operation efficiency is improved. The steam exhaust system of the steam-driven draught fan can realize steam exhaust under normal working conditions and accident working conditions, so that the steam exhaust is efficiently utilized, and the problems of low operation stability, low energy-saving operation efficiency, low energy utilization rate and high energy consumption of the existing draught fan operation method and operation system under the low-load working condition are solved.
According to some embodiments of the invention, each of the steam-driven induced draft fan steam exhaust systems comprises:
the steam seal system comprises a shaft seal heater and a stop valve group connected with the shaft seal heater, and is used for recovering shaft seal leakage steam and heating cooling water so as to reduce the shaft seal leakage steam and heat loss;
the drainage system comprises a main steam regulating valve front drainage device, a main steam regulating valve rear drainage device, a shaft seal pipeline drainage device and a drainage flash tank, wherein the drainage flash tank is used for collecting the exhaust steam liquid formed by the steam discharged by the first steam driven draught fan or the second steam driven draught fan, and the drainage system is used for dredging the exhaust steam liquid into the desulfurization water collecting well.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
The above and additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
FIG. 1 is a flow chart of an operation method of a thermal generator set induced draft fan according to an embodiment of the invention;
fig. 2 is a schematic structural diagram of a steam exhaust system of the steam-driven induced draft fan in the embodiment of the invention.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.
In the description of the present invention, it is to be understood that the directional descriptions, such as the directions of upper, lower, front, rear, left, right, etc., are referred to only for convenience of describing the present invention and for simplicity of description, and are not intended to indicate or imply that the device or element so referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be considered as limiting the present invention.
In the description of the present invention, the meaning of a plurality of means is one or more, the meaning of a plurality of means is two or more, and larger, smaller, larger, etc. are understood as excluding the number, and larger, smaller, inner, etc. are understood as including the number. If the first and second are described for the purpose of distinguishing technical features, they are not to be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated or implicitly indicating the precedence of the technical features indicated.
In the description of the present invention, unless otherwise specifically limited, terms such as set, installation, connection and the like should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above terms in the present invention by combining the specific contents of the technical solutions.
First, before specifically describing the operation method of the induced draft fan of the thermal power generating unit in the embodiment of the present invention, a cold dynamic field experiment needs to be performed on a single electric induced draft fan and a first pneumatic induced draft fan, a total air volume, a current, an inlet pressure and an outlet pressure corresponding to a stationary blade opening of the electric induced draft fan from 0% to 100% are recorded, a total air volume corresponding to a stationary blade opening of the first pneumatic induced draft fan from 0% to 100% at different rotation speeds, a steam inlet damper opening of a steam turbine of the induced draft fan, an inlet pressure and an outlet pressure are recorded, and a corresponding first rotation speed is determined when stationary blade adjustment characteristics of the first pneumatic induced draft fan and the electric induced draft fan are close to each other. In addition, a thermal dynamic field experiment needs to be performed on the electric draught fan and the first pneumatic draught fan, so that the electric draught fan and the first pneumatic draught fan operate in parallel, the rotating speed of a draught fan steam turbine of the first pneumatic draught fan is adjusted to be a first rotating speed, and the distribution conditions of the forces exerted by the current electric draught fan and the first pneumatic draught fan are determined according to the static blade opening, the inlet pressure and the outlet pressure of the current electric draught fan and the first pneumatic draught fan, the current of the electric draught fan, the steam inlet regulating valve opening of the draught fan steam turbine of the first pneumatic draught fan and the experimental data of the cold dynamic field experiment.
A method for operating a thermal generator set induced draft fan according to an embodiment of the first aspect of the present invention is described below with reference to fig. 1 and 2.
The method for operating the induced draft fan of the thermal generator set comprises the following steps:
acquiring unit load of a thermal generator set;
selecting an operation control strategy for the induced draft fan set according to the load of the unit; the operation control strategy comprises a first parallel control strategy, a second parallel control strategy and a third parallel control strategy; the induced draft fan group comprises an electric induced draft fan, a first pneumatic induced draft fan and a second pneumatic induced draft fan;
wherein the first parallel control strategy comprises the steps of: adjusting the negative pressure of the hearth to be within a preset stable range through an electric induced draft fan, and performing parallel operation on a first pneumatic induced draft fan; adjusting the stationary blade opening degree of the electric induced draft fan and the rotating speed and/or the stationary blade opening degree of the first pneumatic induced draft fan until the stationary blade opening degree of the electric induced draft fan is in a fully-closed state, and closing the electric induced draft fan;
the second coordinated control strategy comprises the following steps: adjusting the negative pressure of the hearth to be within a preset stable range through a first pneumatic draught fan, and performing parallel operation on a second pneumatic draught fan; adjusting the rotating speed and/or the stationary blade opening of the first and second pneumatic draught fans until the rotating speed and the stationary blade opening of the first and second pneumatic draught fans are the same;
the third coordinated control strategy comprises the following steps: adjusting the negative pressure of the hearth to be within a preset stable range through a first steam-driven draught fan, and performing parallel operation on electric draught fans; and adjusting the stationary blade opening degree of the electric draught fan and the first pneumatic draught fan until the negative pressure of the hearth is within a preset stable range.
First, the unit load corresponding to the parallel operation of the induced draft fan units is determined by the correspondence relationship between the actual induced draft fan units and the unit loads. The rotating speed of the induced draft fan steam turbine corresponding to the first or second pneumatic induced draft fan before parallel operation is obtained by a cold dynamic field experiment. The preset stable range of the hearth pressure is preset according to the actual situation.
The load of the unit is lower in the initial stage after the boiler is started, and at the moment, the electric induced draft fan is adopted to pump out gas in the flue, so that the stability of the negative pressure of the hearth is maintained. Along with the increase of the load of the unit, when the load of the unit is greater than a preset first switching load value Q1, executing a first parallel control strategy on the induced draft fan unit, adjusting the negative pressure of the hearth to a preset stable range by the electric induced draft fan, starting the first pneumatic induced draft fan (at the moment, the rotating speed of the induced draft fan turbine of the first pneumatic induced draft fan reaches 3000r/min, the opening degree of the static blade keeps a fully closed state), executing parallel operation on the first pneumatic induced draft fan, adjusting the opening degree of the static blade of the electric induced draft fan to adjust the negative pressure of the hearth to positive 200Pa, adjusting the opening degree of the static blade of the first pneumatic induced draft fan to 80%, gradually increasing the rotating speed of the induced draft fan turbine of the first pneumatic induced draft fan, wherein the phenomenon that the negative pressure of the hearth is rapidly reduced at the moment when the first pneumatic induced draft fan generates the output force, and then, the opening degree of the static blade of the electric induced draft fan is reduced downwards to increase the negative pressure of the hearth to the preset stable range, the rotating speed of the induced draft fan steam turbine of the first pneumatic induced draft fan is continuously increased, the static blade opening of the electric induced draft fan is adjusted downwards at the same time (the negative pressure of the hearth is required to be maintained within a preset stable range in the process) until the static blade opening of the electric induced draft fan is in a fully-closed state, and the electric induced draft fan is closed.
The above-mentioned values of the rotation speed, the furnace negative pressure value, and the vane opening are not fixed and need to be determined according to actual conditions, and are not to be construed as limiting the present invention.
The first pneumatic induced draft fan operates independently, when the unit load is larger than a preset second switching load value Q2, the second pneumatic induced draft fan needs to be connected in parallel to match the unit load, and at the moment, a second parallel control strategy is executed on the induced draft fan unit. The rotating speed adjustment and the stationary blade opening adjustment of a first pneumatic draught fan are switched to an automatic state, the rotating speed of the first pneumatic draught fan is reduced downwards to enable the negative pressure of a hearth to reach positive 200Pa, a second pneumatic draught fan is started (at the moment, the rotating speed of a draught fan steam turbine of the second pneumatic draught fan reaches 3000r/min, the stationary blade opening keeps a fully closed state), parallel operation is carried out on the second pneumatic draught fan, the stationary blade opening of the second pneumatic draught fan is adjusted to be identical to the stationary blade opening of the second pneumatic draught fan (both are 80%), then the rotating speed of the second pneumatic draught fan is gradually increased, the rotating speed of the first pneumatic draught fan is gradually reduced, it needs to be noted that the pressure of the hearth is reduced and fluctuated at the moment when the second pneumatic draught fan is subjected to output force, the rotating speed of the first pneumatic draught fan is instantly reduced because of the output force, so that the rotating speed is fluctuated, and the rotating speeds of the first pneumatic draught fan and the second pneumatic draught fan need to be rapidly adjusted, the rotating speeds of the first and second steam-driven draught fans are kept consistent, the opening degree of the steam inlet regulating valves of the two draught fan turbines corresponding to the first and second steam-driven draught fans is required to be adjusted to be basically consistent, the two steam-driven draught fans output equivalent power, and finally the furnace negative pressure is adjusted to be within a stable range, and the first and second steam-driven draught fans are completed in parallel. The first pneumatic draught fan and the second pneumatic draught fan are connected in parallel, a mode of firstly combining the stationary blades and then combining the rotating speeds is adopted, the operation process is simple, and time is saved.
It should be noted that, when the second pneumatic draught fan is started to operate in parallel when the unit load is large, it is necessary to determine whether the stationary blade and the inlet/outlet baffle of the second pneumatic draught fan will alarm due to the excessive front-back differential pressure or will not open, and correct the fault in time.
When the unit load starts to gradually decrease until the unit load is smaller than the preset fourth switching load value Q4, the second pneumatic induced draft fan needs to be exited to match the current unit load, and the specific control process is opposite to the second parallel control strategy, which is not described herein again.
And the first pneumatic induced draft fan operates independently, and when the unit load is smaller than a preset third switching load value Q3, a third parallel control strategy is executed on the induced draft fan unit. The rotary speed regulation and the quiet leaf aperture of first vapour draught fan are adjusted and are cut to automatic status, adjust the rotary speed of first vapour draught fan to the first rotary speed under first vapour draught fan and the electronic draught fan phase-match pressure head, adjust furnace pressure to positive 200Pa, start electronic draught fan, gradually enlarge the quiet leaf aperture of electronic draught fan, gradually reduce the quiet leaf aperture of first vapour draught fan simultaneously, until electronic draught fan takes out power, it is required to explain, can appear furnace negative pressure fast reduction phenomenon in the twinkling of an eye when electronic draught fan goes out power, need adjust the quiet leaf aperture of electronic draught fan and first vapour draught fan, in order to guarantee that furnace pressure maintains and predetermineeing stability range.
According to cold dynamic power field experiments, when the electric induced draft fan is parallel to the first pneumatic induced draft fan, the matching degree of the static blade adjusting characteristic of the induced draft fan steam turbine of the first pneumatic induced draft fan and the static blade adjusting characteristic of the electric induced draft fan is the highest, the rotating speed of the induced draft fan steam turbine of the first pneumatic induced draft fan can be adjusted to 4000r/min constant speed operation, and only the static blade opening degrees of the electric induced draft fan and the first pneumatic induced draft fan are required to be adjusted so that the electric induced draft fan and the first pneumatic induced draft fan can stably operate in parallel.
Here, it should be noted that the positive 200Pa is a negative pressure value at which the furnace pressure is stable, but the negative pressure value cannot be regarded as a fixed negative pressure value at which the furnace pressure is stable, and may fluctuate within a preset stable range, and the preset stable range is determined according to actual conditions and cannot be regarded as a limitation of the present invention. In addition, when the induced draft fan sets are operated in parallel, the pressure of the hearth can be rapidly reduced by 200-400 Pa at the moment of the output force of the parallel fans, so that the pressure of the hearth can be adjusted to be 0-200 Pa before the parallel operation is carried out, and the hearth negative pressure fluctuation during the parallel operation is adapted.
According to the method for operating the induced draft fan of the thermal generator set, after the unit load of the thermal generator set is obtained, the operation control strategy of the induced draft fan set can be selected according to the unit load. The first pneumatic draught fan can be arranged in parallel when the electric draught fan operates through a first parallel control strategy, the electric draught fan is arranged in parallel, and the negative pressure of the hearth is stable, so that the electric draught fan is switched to the first pneumatic draught fan. And a second parallel control strategy is adopted to enable a second pneumatic draught fan to be parallel to the first pneumatic draught fan when the first pneumatic draught fan runs so as to match the raised unit load. And the electric induced draft fans can be arranged in parallel when the first pneumatic induced draft fan runs through a third parallel control strategy so as to match the reduced unit load. By executing the operation control strategy of the induced draft fan unit, the automatic switching of the electric induced draft fan, the first pneumatic induced draft fan and the second pneumatic induced draft fan under different unit loads can be realized, the first pneumatic induced draft fan can be put into use in advance, the low-load working condition is adapted, the energy consumption is reduced, the energy-saving operation efficiency is improved, and the problems of low operation stability, low energy-saving operation efficiency and high energy consumption of the existing induced draft fan operation method and operation system under the low-load working condition are solved.
In some embodiments of the present invention, selecting an operation control strategy for the induced air handling unit according to the unit load comprises the following steps:
if the unit load is greater than a preset first switching load value Q1, executing a first parallel control strategy on the induced draft fan unit;
if the unit load is greater than a preset second switching load value Q2, executing a second parallel control strategy on the induced draft fan unit;
if the unit load is smaller than a preset third switching load value Q3, executing a third parallel control strategy on the induced draft fan unit; the first switching load value Q1 is smaller than the third switching load value Q3, and the third switching load value Q3 is smaller than the second switching load value Q2.
The load of the unit is lower in the initial stage after the boiler is started, and at the moment, the electric induced draft fan is adopted to pump out gas in the flue, so that the stability of the negative pressure of the hearth is maintained. Along with the rise of the unit load, when the unit load is larger than the maximum load value which can be born by the electric induced draft fan, the electric induced draft fan cannot work normally, and a certain time is needed in the parallel process, so that the first pneumatic induced draft fan needs to be arranged in parallel in advance before the unit load reaches the maximum load value which can be born by the electric induced draft fan so as to adapt to the raised unit load. When the unit load is larger than the maximum load value which can be borne by a single first pneumatic draught fan, the first pneumatic draught fan cannot normally work, so that a second pneumatic draught fan needs to be arranged in parallel in advance before the unit load reaches the maximum load value which can be borne by the first pneumatic draught fan so as to adapt to the raised unit load.
If the unit load begins to gradually decrease, the energy-saving operation efficiency of the parallel operation of the first and second pneumatic draught fans is low, the energy consumption is high, and when the unit load decreases to be less than a preset fourth switching load value Q4, the second pneumatic draught fan needs to be withdrawn in advance. When a single first pneumatic draught fan works, the unit load is continuously reduced, the energy-saving operation efficiency of the single first pneumatic draught fan is low, the energy consumption is high, and the electric draught fan needs to be arranged in parallel before the unit load is reduced to the maximum load value which can be borne by the electric draught fan, so that the energy-saving operation efficiency is improved while the unit load is matched.
Here, it should be noted that, in an extreme condition, the induced draft fan group is not required to be operated in parallel for a certain time, and then the first switching load value Q1 is equal to the third switching load value Q3, and the second switching load value Q2 is equal to the fourth switching load value Q4.
In some embodiments, the preset first switching load value Q1 is 30% load, the second switching load value Q2 is 40% load, the third switching load value Q3 is 35% load, and the fourth switching load value Q4 is 45% load. The unit load that needs to be handled in parallel is determined by the correspondence relationship between the actual air inducing unit and the unit load, and the specific values of the preset first switching load value Q1, second switching load value Q2, third switching load value Q3, and fourth switching load value Q4 are not to be construed as limiting the present invention.
In some embodiments of the present invention, adjusting the stationary blade opening of the electric induced draft fan and the rotational speed and/or the stationary blade opening of the first pneumatic induced draft fan includes the steps of:
increasing the stator blade opening of the first pneumatic induced draft fan to the optimal stator blade opening position;
and increasing the rotating speed of the first pneumatic induced draft fan, and reducing the stationary blade opening degree of the electric induced draft fan until the stationary blade opening degree of the electric induced draft fan is in a full-closed state.
Increase first vapour dynamic draught fan's quiet leaf aperture to 80% position, the rotational speed of the draught fan steam turbine of first vapour dynamic draught fan progressively risees, it needs to explain that, can appear furnace negative pressure and reduce the phenomenon fast in the twinkling of an eye at first vapour dynamic draught fan output, the quiet leaf aperture of electronic draught fan is adjusted down this moment, make furnace negative pressure rise to predetermine the stability within range after, continue to rise the rotational speed of the draught fan steam turbine of first vapour dynamic draught fan, adjust down the quiet leaf aperture of electronic draught fan simultaneously (this process need maintain the furnace negative pressure and predetermine the stability within range), it is the totally-closed state to the quiet leaf aperture of electronic draught fan. The optimum vane opening position is the 80% position, but this is not to be construed as limiting the present invention.
In some embodiments of the invention, the boiler is ignited by an electrically powered induced draft fan when the boiler is started. The electric draught fan is adopted to ignite and support combustion of the boiler, so that the air induction quantity can be effectively controlled, the combustion degree of the boiler is controlled, the unit load at the starting stage of the boiler is low, and the electric draught fan can be matched with the low-load working condition of the boiler.
In some embodiments of the present invention, the first or second induced draft fan performs the following steps in the start-up phase:
adjusting an induced draft fan steam turbine corresponding to the first or second pneumatic induced draft fan to a preset remote control minimum rotating speed, and adjusting the negative pressure of the hearth to be within a preset stable range by adjusting the stationary blade opening of the first or second pneumatic induced draft fan;
adjusting the stationary blade opening of the first or second pneumatic draught fan to a preset stationary blade economic opening position according to the air volume of the boiler or the unit load, and adjusting the negative pressure of the hearth to be within a preset stable range by adjusting the rotating speed of a draught fan steam turbine corresponding to the first or second pneumatic draught fan;
adjusting the opening of a stationary blade of the first or second pneumatic draught fan to an opening preset value corresponding to the current unit load; the preset opening value is obtained by a fitting function between the opening of the stator blade and the load of the unit.
The method comprises the steps that after warming-up of an induced draft fan turbine corresponding to a first pneumatic induced draft fan or a second pneumatic induced draft fan is completed, the speed is automatically increased to 2650r/min, furnace negative pressure is stabilized by adjusting the stationary blade opening of the first pneumatic induced draft fan or the second pneumatic induced draft fan, along with the rising of the air volume of a boiler or unit load, the stationary blade opening of the first pneumatic induced draft fan or the second pneumatic induced draft fan is gradually increased to 52%, the furnace negative pressure is stabilized by adjusting the rotating speed of the induced draft fan turbine corresponding to the first pneumatic induced draft fan or the second pneumatic induced draft fan, the stationary blade opening of the first pneumatic induced draft fan or the second pneumatic induced draft fan is adjusted to a preset opening value corresponding to the current unit load, and therefore a starting control strategy in the starting process of the boiler is completed. It should be noted that the specific values mentioned above are obtained from experimental data of cold dynamic field experiments, but should not be construed as limiting the present invention. In addition, for the shutdown control strategy in the unit load reduction shutdown process, the switching process of the rotation speed adjustment and the stationary blade adjustment of the first pneumatic draught fan or the second pneumatic draught fan is opposite to the starting process, and details are not described herein. The starting control strategy and the stopping control strategy of the first pneumatic draught fan or the second pneumatic draught fan realize the purposes of safe, reliable, automatic starting and stopping, economy and energy conservation.
In some embodiments of the present invention, the vane economic opening and the opening preset value are obtained by:
obtaining a plurality of first unit loads, and determining the stationary blade economic opening of a first pneumatic induced draft fan or a second pneumatic induced draft fan which corresponds to the plurality of first unit loads one by one; the economic opening of the static blade is used for representing the corresponding static blade opening when the energy consumption of the induced draft fan steam turbine is the lowest;
and (4) making a fitting function according to the economic opening of the plurality of stationary blades, and determining corresponding preset opening values under different unit loads according to the fitting function.
The economical efficiency of the operation of the steam-driven draught fan is mainly determined by the opening degree of the static blade under the variable load working condition, and the economical efficiency of the operation of the steam turbine of the draught fan corresponding to the steam-driven draught fan is mainly related to the rotating speed of the steam turbine and the throttling degree of the steam inlet regulating valve. The method comprises the steps of analyzing an operation performance curve of the steam-driven draught fan and performance parameters of a steam turbine of the draught fan, adopting stationary blade opening degrees close to stationary blade economic opening degrees for different unit loads, determining the stationary blade economic opening degrees of the steam-driven draught fan with different unit loads by comparing steam consumption tests of the steam turbine of the draught fan, and obtaining an optimal solution set through fitting piecewise functions to obtain opening degree preset values of the steam-driven draught fan under each unit load and each working condition.
When the load of the unit is increased to a normal operation condition, the inlet stationary blade of the steam-driven induced draft fan is controlled in an open loop mode, and the opening instruction is generated by superposing the load instruction of the unit and the movable blade instruction of the air feeder. The method comprises the steps of respectively setting 2-3 opening deviation points at two ends of the economic opening of the stationary blade of the steam-driven induced draft fan at a typical unit load point, testing and comparing steam flow, searching for an optimal economic opening point, fitting a piecewise function, and ensuring that the stationary blade opening runs at the position of the economic opening of the stationary blade, wherein the opening point is required to be within the required range of the air quantity, the opening of the stationary blade and the air pressure characteristic curve of the induced draft fan.
Under the condition of full load, because the vibration characteristic of the steam-driven induced draft fan is limited, the stationary blade opening corresponding to the highest rotating speed 5200R/min of the turbine of the induced draft fan exceeds the economic opening range, so on the premise of ensuring safety, the boundary limitation needs to be carried out on the highest rotating speed and the minimum stationary blade opening during full load, and the boundary opening is the maximum rotating speed RmaxMost correspondingSmall opening YminI.e. Y ≧ Ymin，R≤RmaxWherein R ismaxAnd YminThe full-load stator blade opening degree is determined to be 90% through the test.
The minimum steam consumption constraint function relationship is as follows: y ism＝F(X0)，(FminF (X, y)), wherein X0As unit load, Y0Table 1 shows the partial correspondence relationship between the unit load and the vane economic opening, and table 1 shows the partial correspondence relationship between the unit load and the vane economic opening.
TABLE 1
Figure BDA0003557821940000141
Under the working condition of auxiliary machine fault load Reduction (RB), the rotating speed and the stationary blade opening of the induced draft fan steam turbine are increased by an opening preset value through a closed-loop fast loop at the same time, so that the requirement of rapidly increasing the output of a pneumatic induced draft fan in opposite operation under the working condition of RB is met, wherein the magnitude of the increase is related to the unit load when the induced draft fan RB occurs. According to actual test, actual operation record and the minimum fluctuation target range of negative pressure of the hearth, a fitting function relation (shown in table 2) corresponding to the excess relaxation quantity of the unit load and the opposite side stationary blade opening is preliminarily determined, and through repeated RB actual action record of the induced draft fan, the opening preset value is further optimized, experimental data are configured into a program of a DCS (distributed control system), so that the operation effect of the steam-driven induced draft fan is optimized through the experimental result.
TABLE 2
Figure BDA0003557821940000142
Under the working condition of Main Fuel Tripping (MFT), the opening of the static blade of the turbine of the induced draft fan automatically gives a static blade reduction set value according to the unit load before tripping under the action of a closed loop fast loop, so that the variation of the furnace hearth negative pressure overrun under the working condition of the MFT is effectively controlled, the fitting functional relation (shown in a table 3) of the unit load and the static blade opening overrun is determined through field tests and data analysis of the actual MFT working condition, parameters are recorded through the actual action of the MFT, and the opening preset value is further optimized.
TABLE 3
Figure BDA0003557821940000151
The static blade can be quickly adjusted by overriding under special working conditions, so that the severe fluctuation range of negative pressure of a hearth is reduced, the safety of a boiler under the variable-load working condition is ensured, and the aim of the whole-course economic operation of the steam-driven draught fan is fulfilled.
In some embodiments of the invention, an auxiliary burner or a plasma burner is introduced to stabilize the boiler before the first, second, and third parallel control strategies are executed. When the two fans are operated in parallel, the pressure fluctuation of the hearth is large, and before the first parallel control strategy, the second parallel control strategy and the third parallel control strategy are executed, an auxiliary combustor or a plasma combustor is put into the hearth to stabilize the combustion of the boiler.
A thermal generator set induced draft fan operation system according to an embodiment of the second aspect of the present invention is described below with reference to fig. 1 and 2.
According to the embodiment of the invention, the operation system of the induced draft fan of the thermal generator set comprises the following components:
the unit load acquisition unit is used for acquiring the unit load of the thermal generator set;
the control strategy selection unit is used for selecting an operation control strategy of the induced draft fan set according to the load of the unit; the operation control strategy comprises a first parallel control strategy, a second parallel control strategy and a third parallel control strategy; the induced draft fan group comprises an electric induced draft fan, a first pneumatic induced draft fan and a second pneumatic induced draft fan;
a first parallel operation control unit for executing a first parallel control strategy; the first parallel control strategy comprises the steps of: adjusting the negative pressure of the hearth to be within a preset stable range through an electric induced draft fan, and performing parallel operation on a first pneumatic induced draft fan; adjusting the stationary blade opening degree of the electric induced draft fan and the rotating speed and/or the stationary blade opening degree of the first pneumatic induced draft fan until the stationary blade opening degree of the electric induced draft fan is in a fully-closed state, and closing the electric induced draft fan;
a second parallel operation control unit for executing a second parallel control strategy; the second coordinated control strategy comprises the following steps: adjusting the negative pressure of the hearth to be within a preset stable range through a first pneumatic draught fan, and performing parallel operation on a second pneumatic draught fan; adjusting the rotating speed and/or the stationary blade opening of the first and second pneumatic draught fans until the rotating speed and the stationary blade opening of the first and second pneumatic draught fans are the same;
a third parallel operation control unit for executing a third parallel control strategy; the third coordinated control strategy comprises the following steps: adjusting the negative pressure of the hearth to be within a preset stable range through a first steam-driven draught fan, and performing parallel operation on electric draught fans; and adjusting the stationary blade opening degrees of the electric draught fan and the first pneumatic draught fan until the negative pressure of the hearth is within a preset stable range.
The load of the unit is lower in the initial stage after the boiler is started, and at the moment, the electric induced draft fan is adopted to pump out gas in the flue, so that the stability of the negative pressure of the hearth is maintained. And when the unit load is greater than a preset first switching load value Q1, executing a first parallel control strategy on the induced draft fan unit. Firstly, an electric draught fan adjusts the negative pressure of a hearth to be within a preset stable range, a first pneumatic draught fan is started (at the moment, the rotating speed of a draught fan steam turbine of the first pneumatic draught fan reaches 3000r/min, the opening degree of a static blade keeps a fully closed state), parallel operation is carried out on the first pneumatic draught fan, the opening degree of the static blade of the electric draught fan is adjusted to adjust the negative pressure of the hearth to be 200Pa, the opening degree of the static blade of the first pneumatic draught fan is adjusted to be 80%, the rotating speed of the draught fan steam turbine of the first pneumatic draught fan is gradually increased, the phenomenon that the negative pressure of the hearth is rapidly reduced at the moment when the first pneumatic draught fan outputs force needs to be described, the opening degree of the static blade of the electric draught fan is reduced at the moment, the rotating speed of the draught fan steam turbine of the first pneumatic draught fan is continuously increased after the negative pressure of the hearth is increased to be within the preset stable range, and the opening degree of the static blade of the electric draught fan is reduced at the same time (the process needs to maintain the negative pressure of the hearth to be within the preset stable range), and (4) turning off the electric induced draft fan until the opening degree of the static blade of the electric induced draft fan is in a full-closed state.
The first pneumatic induced draft fan operates independently, when the unit load is larger than a preset second switching load value Q2, the second pneumatic induced draft fan needs to be connected in parallel to match the unit load, and at the moment, a second parallel control strategy is executed on the induced draft fan unit. Switching the rotation speed regulation and the stationary blade opening regulation of a first pneumatic draught fan to an automatic state, reducing the rotation speed of the first pneumatic draught fan to ensure that the negative pressure of a hearth reaches positive 200Pa, starting a second pneumatic draught fan (at the moment, the rotation speed of a draught fan steam turbine of the second pneumatic draught fan reaches 3000r/min, and the stationary blade opening keeps a fully closed state), executing parallel operation on the second pneumatic draught fan, regulating the stationary blade opening of the second pneumatic draught fan to be the same as the stationary blade opening of the second pneumatic draught fan (both are 80%), gradually increasing the rotation speed of the second pneumatic draught fan, and simultaneously reducing the rotation speed of the first pneumatic draught fan step by step, wherein the rotation speed of the first pneumatic draught fan is required to be regulated rapidly because the hearth pressure reduction fluctuation occurs at the moment of the output of the second pneumatic draught fan and the rotation speed fluctuation occurs because the output of the first pneumatic draught fan is reduced at the moment, the rotating speeds of the first and second steam-driven draught fans are kept consistent, the opening degree of the steam inlet regulating valves of the two draught fan turbines corresponding to the first and second steam-driven draught fans is required to be adjusted to be basically consistent, the two steam-driven draught fans output equivalent power, and finally the furnace negative pressure is adjusted to be within a preset stable range, and the first and second steam-driven draught fans are completed in parallel. The first pneumatic draught fan and the second pneumatic draught fan are connected in parallel, a mode of firstly combining the stationary blades and then combining the rotating speeds is adopted, the operation process is simple, and time is saved.
When the unit load starts to gradually decrease until the unit load is smaller than the preset fourth switching load value Q4, the second pneumatic induced draft fan needs to be exited to match the current unit load, and the specific control process is opposite to the second parallel control strategy, which is not described herein again.
And the first pneumatic induced draft fan operates independently, and when the unit load is smaller than a preset third switching load value Q3, a third parallel control strategy is executed on the induced draft fan unit. The rotary speed regulation and the quiet leaf aperture of first vapour draught fan are adjusted and are cut to automatic status, adjust the rotary speed of first vapour draught fan to the first rotary speed under first vapour draught fan and the electronic draught fan phase-match pressure head, adjust furnace pressure to positive 200Pa, start electronic draught fan, gradually increase electronic draught fan's quiet leaf aperture, gradually reduce the quiet leaf aperture of first vapour draught fan simultaneously, until electronic draught fan area is exerted power, need explain, can appear furnace negative pressure fast reduction phenomenon in the twinkling of an eye in electronic draught fan output, need adjust the quiet leaf aperture of electronic draught fan and first vapour draught fan, in order to guarantee that furnace pressure maintains and predetermine stability range.
According to the thermal generator set induced draft fan operation system provided by the embodiment of the invention, the unit load of the thermal generator set can be acquired through the unit load acquisition unit, and the operation control strategy of the induced draft fan set can be selected through the control strategy selection unit according to the unit load. The first parallel control strategy can be executed through the first parallel operation control unit, so that the first pneumatic draught fan is arranged in parallel when the electric draught fan operates, the electric draught fan is closed after parallel completion and the negative pressure of the hearth is stable, and switching from the electric draught fan to the first pneumatic draught fan is realized. And the second parallel operation control unit can execute a second parallel control strategy, so that the second pneumatic draught fan is parallel when the first pneumatic draught fan operates, and the increased unit load is matched. And the third parallel operation control unit can execute a third parallel control strategy, so that the electric induced draft fans are parallel when the first pneumatic induced draft fan runs, and the reduced unit load is matched. By executing the operation control strategy of the induced draft fan unit, the automatic switching of the electric induced draft fan, the first pneumatic induced draft fan and the second pneumatic induced draft fan under different unit loads can be realized, the first pneumatic induced draft fan can be put into use in advance, the low-load working condition is adapted, the energy consumption is reduced, the energy-saving operation efficiency is improved, and the problems of low operation stability, low energy-saving operation efficiency and high energy consumption of the existing induced draft fan operation method and operation system under the low-load working condition are solved.
A thermal power generating unit induced draft fan operation device according to an embodiment of a third aspect of the present invention is described below with reference to fig. 1 and 2.
According to the embodiment of the invention, the operation device of the induced draft fan of the thermal generator set comprises:
the induced draft fan unit comprises an electric induced draft fan, a first pneumatic induced draft fan and a second pneumatic induced draft fan; the air guide unit is used for exhausting steam generated by combustion of the boiler so as to maintain the pressure of the hearth;
the two steam-driven induced draft fans are connected with the first steam-driven induced draft fan and the second steam-driven induced draft fan in a one-to-one correspondence manner;
and the DCS is used for executing the operation method of the induced draft fan of the thermal generator set in the embodiment of the invention.
And after the unit load of the thermal generator set is acquired through the DCS, selecting an operation control strategy for the induced draft fan set according to the unit load. The first parallel control strategy is adopted to realize that the first pneumatic draught fans are arranged in parallel when the electric draught fans operate, the parallel operation is finished, and the electric draught fans are closed after the negative pressure of the hearth is stable. And realizing the parallel connection of the second pneumatic draught fan when the first pneumatic draught fan operates by a second parallel control strategy so as to match the raised unit load. And realizing parallel electric induced draft fans when the first pneumatic induced draft fan operates by a third parallel control strategy so as to match the reduced unit load. The automatic switching of the electric induced draft fan, the first pneumatic induced draft fan and the second pneumatic induced draft fan under different unit loads can be realized, the first pneumatic induced draft fan can be put into use in advance, the low-load working condition is adapted, the energy consumption is reduced, and the energy-saving operation efficiency is improved. It should be noted that the DCS system is known in the art, and will not be described herein.
When the induced draft fan steam turbine is in the operation process, high-pressure steam may leak outwards through the high-pressure shaft end and even enter the bearing box to cause water to enter lubricating oil. In addition, the induced draft fan steam turbine can gather condensed water in equipment and pipelines in the starting process and low-parameter operation, if drainage is not smooth, the equipment and the pipelines can be deformed, and a water hammer phenomenon can be generated seriously, so that severe vibration is caused, and the equipment and the pipelines are damaged. Can prevent through the steam-driven draught fan steam exhaust system that high-pressure steam from outwards leaking through the high-pressure axle head, can retrieve working medium and heat simultaneously, improve the economic nature and the security of draught fan steam turbine to in time hydrophobic, prevent to gather the condensate water and lead to equipment and system to break down in equipment and the pipeline.
As shown in fig. 2, under normal working conditions, exhaust steam is led to the deaerator, the primary air fan heater, the GGH auxiliary heater and the low-pressure steam supply pipeline, and under accident working conditions, exhaust steam is led to the drainage flash tank, so that the exhaust steam can be utilized more efficiently, and the energy utilization rate is improved.
According to the thermal generator set induced draft fan operation device provided by the embodiment of the invention, the automatic switching of the electric induced draft fan, the first pneumatic induced draft fan and the second pneumatic induced draft fan under different unit loads can be realized through the DCS, the first pneumatic induced draft fan can be used in advance, the device is suitable for low-load working conditions, the energy consumption is reduced, and the energy-saving operation efficiency is improved. The steam exhaust system of the steam-driven draught fan can realize steam exhaust under normal working conditions and accident working conditions, so that the steam exhaust is efficiently utilized, and the problems of low operation stability, low energy-saving operation efficiency, low energy utilization rate and high energy consumption of the existing draught fan operation method and operation system under the low-load working condition are solved.
In some embodiments of the present invention, referring to fig. 2, each of the steam-driven induced draft fan steam-discharging systems includes:
the steam seal system comprises a shaft seal heater and a stop valve group connected with the shaft seal heater, and is used for recovering shaft seal steam leakage and heating cooling water so as to reduce the shaft seal steam leakage and heat loss;
the drainage system comprises a front drainage device of the main steam control valve, a rear drainage device of the main steam control valve, a shaft seal pipeline drainage device and a drainage flash tank, wherein the drainage flash tank is used for collecting exhaust liquid formed by steam discharged by the first steam-driven draught fan or the second steam-driven draught fan, and the drainage system is used for draining the exhaust liquid into the desulfurization water collecting well.
The shaft seal heater can recover shaft seal leakage steam and heat cooling water so as to reduce the shaft seal leakage steam and heat loss and improve the economy and safety of the induced draft fan steam turbine. Through the front drainage device of the main steam control valve, the rear drainage device of the main steam control valve and the shaft seal pipeline drainage device, the discharged steam liquid formed by the steam discharged by the first steam-driven draught fan or the second steam-driven draught fan can be drained into the drainage flash tank and discharged into the desulfurization water collecting well, so that the equipment and the system are prevented from being broken down due to the fact that condensed water is collected in the equipment and the pipeline.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
Although the embodiments of the present invention have been described in detail with reference to the accompanying drawings, the present invention is not limited to the embodiments, and those skilled in the art will understand that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims (10)

1. An operation method of a thermal generator set induced draft fan is characterized by comprising the following steps:
acquiring unit load of a thermal generator set;
selecting an operation control strategy for the induced draft fan set according to the unit load; the operation control strategy comprises a first parallel control strategy, a second parallel control strategy and a third parallel control strategy; the induced draft fan set comprises an electric induced draft fan, a first pneumatic induced draft fan and a second pneumatic induced draft fan;
wherein the first parallel control strategy comprises the steps of: adjusting the negative pressure of the hearth to be within a preset stable range through the electric induced draft fan, and performing parallel operation on the first pneumatic induced draft fan; adjusting the stationary blade opening degree of the electric induced draft fan and the rotating speed and/or the stationary blade opening degree of the first pneumatic induced draft fan until the stationary blade opening degree of the electric induced draft fan is in a full-closed state, and closing the electric induced draft fan;
the second coordinated control strategy comprises the steps of: adjusting the negative pressure of the hearth to be within the preset stable range through the first pneumatic induced draft fan, and performing parallel operation on the second pneumatic induced draft fan; adjusting the rotating speed and/or the stationary blade opening of the first and second pneumatic draught fans until the rotating speed and the stationary blade opening of the first and second pneumatic draught fans are the same;
the third coordinated control strategy comprises the following steps: adjusting the negative pressure of the hearth to be within the preset stable range through the first pneumatic induced draft fan, and performing parallel operation on the electric induced draft fans; and adjusting the stationary blade opening degree of the electric induced draft fan and the first pneumatic induced draft fan until the negative pressure of the hearth is in the preset stable range.
2. The method for operating the induced draft fan of the thermal generator set according to claim 1, wherein the step of selecting the operation control strategy for the induced draft fan set according to the unit load comprises the following steps:
if the unit load is larger than a preset first switching load value, executing the first parallel control strategy on the induced draft fan unit;
if the unit load is larger than a preset second switching load value, executing the second parallel control strategy on the induced draft fan unit;
if the unit load is smaller than a preset third switching load value, the third parallel control strategy is executed on the induced draft fan unit; the first handover load value is smaller than the third handover load value, and the third handover load value is smaller than the second handover load value.
3. The method for operating the induced draft fan of the thermal generator set according to claim 1, wherein the adjusting of the stationary blade opening degree of the electric induced draft fan and the rotating speed and/or the stationary blade opening degree of the first pneumatic induced draft fan comprises the following steps:
increasing the stator blade opening of the first pneumatic induced draft fan to the optimal stator blade opening position;
and increasing the rotating speed of the first pneumatic draught fan, reducing the static blade opening degree of the electric draught fan until the static blade opening degree of the electric draught fan is in a fully-closed state.
4. The method for operating the induced draft fan of the thermal generator set according to claim 1, wherein the boiler is ignited by the electric induced draft fan when the boiler is started.
5. The method for operating the induced draft fan of the thermal generator set according to claim 1, wherein the first or second steam induced draft fan executes the following steps in a starting stage:
adjusting an induced draft fan steam turbine corresponding to the first or second pneumatic induced draft fan to a preset minimum remote control rotation speed, and adjusting the negative pressure of the hearth to be within the preset stable range by adjusting the stationary blade opening of the first or second pneumatic induced draft fan;
adjusting the stationary blade opening of the first or second pneumatic draught fan to a preset stationary blade economic opening position according to the air volume of the boiler or the unit load, and adjusting the hearth negative pressure to be within the preset stable range by adjusting the rotating speed of a draught fan steam turbine corresponding to the first or second pneumatic draught fan;
adjusting the opening degree of the stationary blade of the first or second pneumatic induced draft fan to an opening degree preset value corresponding to the current unit load; the preset opening value is obtained by a fitting function between the opening of the stator blade and the load of the unit.
6. The method for operating the induced draft fan of the thermal generator set according to claim 1, wherein before the first parallel control strategy, the second parallel control strategy and the third parallel control strategy are executed, an auxiliary burner or a plasma burner is put into the method to stabilize combustion of the boiler.
7. A computer-readable storage medium, wherein the computer-readable storage medium stores computer-executable instructions for causing a computer to execute the method for operating a thermal generator set induced draft fan according to any one of claims 1 to 6.
8. The utility model provides a thermal generator set draught fan operating system which characterized in that includes:
the unit load acquisition unit is used for acquiring the unit load of the thermal generator set;
the control strategy selection unit is used for selecting an operation control strategy for the induced draft fan set according to the unit load; the operation control strategy comprises a first parallel control strategy, a second parallel control strategy and a third parallel control strategy; the induced draft fan set comprises an electric induced draft fan, a first pneumatic induced draft fan and a second pneumatic induced draft fan;
a first parallel operation control unit for executing the first parallel control strategy; the first parallel control strategy comprises the steps of: adjusting the negative pressure of the hearth to be within a preset stable range through the electric induced draft fan, and performing parallel operation on the first pneumatic induced draft fan; adjusting the stationary blade opening degree of the electric induced draft fan and the rotating speed and/or the stationary blade opening degree of the first pneumatic induced draft fan until the stationary blade opening degree of the electric induced draft fan is in a fully-closed state, and closing the electric induced draft fan;
a second parallel operation control unit for executing the second parallel control strategy; the second coordinated control strategy comprises the steps of: adjusting the negative pressure of the hearth to be within the preset stable range through the first pneumatic induced draft fan, and performing parallel operation on the second pneumatic induced draft fan; adjusting the rotating speed and/or the stationary blade opening of the first and second pneumatic draught fans until the rotating speed and the stationary blade opening of the first and second pneumatic draught fans are the same;
a third parallel operation control unit for executing the third parallel control strategy; the third coordinated control strategy comprises the steps of: adjusting the negative pressure of the hearth to be within the preset stable range through the first pneumatic induced draft fan, and performing parallel operation on the electric induced draft fans; and adjusting the stationary blade opening degree of the electric induced draft fan and the first pneumatic induced draft fan until the negative pressure of the hearth is in the preset stable range.
9. The utility model provides a thermal generator set draught fan running device which characterized in that includes:
the induced draft fan unit comprises an electric induced draft fan, a first pneumatic induced draft fan and a second pneumatic induced draft fan; the draught fan set is used for exhausting steam generated by combustion of the boiler so as to maintain the pressure of the hearth;
the two steam-driven induced draft fans are connected with the first steam-driven induced draft fan and the second steam-driven induced draft fan in a one-to-one correspondence manner;
the DCS is used for executing the method for operating the induced draft fan of the thermal generator set according to any one of claims 1 to 6.
10. The thermal power generating unit induced draft fan operating device of claim 9, wherein each said steam-operated induced draft fan steam exhaust system all includes:
the steam sealing system comprises a shaft seal heater and a stop valve group connected with the shaft seal heater, and is used for recovering shaft seal steam leakage and heating cooling water so as to reduce the shaft seal steam leakage and heat loss;
the drainage system comprises a main steam regulating valve front drainage device, a main steam regulating valve rear drainage device, a shaft seal pipeline drainage device and a drainage flash tank, wherein the drainage flash tank is used for collecting the exhaust steam liquid formed by the steam discharged by the first steam driven draught fan or the second steam driven draught fan, and the drainage system is used for dredging the exhaust steam liquid into the desulfurization water collecting well.
CN202210284821.7A 2022-03-22 2022-03-22 Method, system and device for operating induced draft fan of thermal generator set Pending CN114607632A (en)

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