CN110296436B - Method for improving success rate and starting stability of boiler fire suppression restart by computer - Google Patents

Method for improving success rate and starting stability of boiler fire suppression restart by computer Download PDF

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Publication number
CN110296436B
CN110296436B CN201910614709.3A CN201910614709A CN110296436B CN 110296436 B CN110296436 B CN 110296436B CN 201910614709 A CN201910614709 A CN 201910614709A CN 110296436 B CN110296436 B CN 110296436B
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boiler
coal
unlocking
bed
air
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CN110296436A (en
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李治儒
杨虹
施治学
王琳琳
高战胜
高超
曲波
武振剑
赵国明
杨忠全
万发光
秦立国
王海涛
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Veolia Harbin Thermal Power Co Ltd
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Veolia Harbin Thermal Power Co Ltd
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
    • F23C10/00—Fluidised bed combustion apparatus
    • F23C10/18—Details; Accessories
    • F23C10/28—Control devices specially adapted for fluidised bed, combustion apparatus
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
    • F23C10/00—Fluidised bed combustion apparatus
    • F23C10/18—Details; Accessories
    • F23C10/28—Control devices specially adapted for fluidised bed, combustion apparatus
    • F23C10/30—Control devices specially adapted for fluidised bed, combustion apparatus for controlling the level of the bed or the amount of material in the bed
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N1/00—Regulating fuel supply
    • F23N1/02—Regulating fuel supply conjointly with air supply
    • F23N1/022—Regulating fuel supply conjointly with air supply using electronic means

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Fluidized-Bed Combustion And Resonant Combustion (AREA)

Abstract

The invention relates to a method for improving the success rate of restarting boiler fire suppression and the starting stability by a computer. The pressure and fire raising of the circulating fluidized bed boiler are important operations, the requirement on the operation level of operators is high, and if the air and coal consumption is not well mastered in the operation time, accidents are easily caused, so that the possibility of manual misoperation is avoided through data obtained by cold state experiments and multiple times of pressure and fire raising, and the safety and the economical efficiency of the operation of the boiler during fire raising are improved through computer control.

Description

Method for improving success rate and starting stability of boiler fire suppression restart by computer
The technical field is as follows:
the invention relates to a method for improving the success rate of boiler fire suppression and restarting and the starting stability by a computer.
Background art:
compared with a pulverized coal furnace, the circulating fluidized bed boiler has a function of suppressing fire heat standby, but in the fire raising operation after suppressing fire, if the fluidization condition of bed materials is singly considered, the control of primary air quantity and coal supply quantity is not well mastered, the operation and adjustment time is not correct, so that too much heat is taken away, the bed temperature cannot be raised, and the fire raising failure condition is caused; the existing fire raising method only depends on a cold fluidization test singly, the obtained lowest fluidization air volume is used as the air volume during fire raising, the comparison between the air volume during the hot state of a boiler and the air volume during the cold state is not considered, the temperature is different, the air density is different, the required air volume is different, even the experienced operators consider the difference between the supercooled state and the hot state, the actually required air volume is judged by experience, a reliable theory and a test basis are not available, the experience of each operator is different, the understanding of the working state of equipment is also different, the operation method and the opportunity are also different, the failure rate of the fire suppressing during starting operation is high, the fluctuation of bed temperature and other parameters during the fire raising process is large, and the fire raising oil consumption and the risk of over-temperature coking and deflagration of a material layer are increased.
The invention content is as follows:
the invention aims to provide a method for improving the success rate of the boiler pressure fire restarting and the starting stability by a computer, which can ensure the fire raising starting, reduce the accident risk of material layer coking and save the oil consumption of the fire raising starting. The technical scheme of the invention is as follows:
a method for improving the success rate and the starting stability of the boiler fire suppression restart by a computer comprises the following steps:
1) and during the cold fluidization test of the boiler, the air quantity is changed along with the primary air quantity FltIncrease of (2), plenum pressure PltIncrease correspondingly at the air quantity FltWhen the air speed is increased to a certain value, the pressure of the air chamber has a tendency of instantaneous decrease, i.e. when the flow speed of the air passing through the fixed bed material is very low, the bed pressure drop is increased proportionally with the increase of the air speed, and when the air speed reaches a certain value, the bed pressure drop reaches a maximum value which is slightly larger than the bed static pressure, if the air speed is continuously increased, the bed pressure drops to a certain valueThe pressure drop of the bed layer is reduced to the static pressure of the bed layer, the phenomenon is called as the unlocking phenomenon of the circulating fluidized bed boiler, and the air volume F during the unlocking phenomenon is recordedltjsAnd corresponding plenum pressure Pltjs(ii) a As shown in fig. 1.
2) After the boiler is started to operate, the working condition of the boiler is changed from a cold state to a hot state, and when the boiler is subjected to fire suppression, the method comprises the following steps: the fluidized bed boiler cuts off fuel, stops the fan and stops the boiler from running in a short time; taking the parameter when the unlocking phenomenon occurs as a reference, and converting the primary air quantity FrtyhReducing the unlocking air quantity F to be less than that of the cold testltjsThen, the primary air quantity F is increasedrtyhAt this time, the air chamber pressure Prtyh has a trend of increasing, then decreasing, and then increasing, that is, an unlocking phenomenon point of thermal state pressure fire appears, as shown in fig. 2;
3) after finding the unlocking phenomenon point in the hot state, recording the hot state unlocking air quantity FrtjsAnd a thermal state unlocking pressure PrtjsThermal unlocking air quantity FrtjsAs the wind quantity when the fire is raised, and recording the current fan frequency frtAnd recording the ratio K of the coal quantity to the air quantity in normal and stable operationmf(ton/hour)/(cubic meter/hour) as the amount of coal corresponding to a certain air flow, i.e., the amount of coal Nml＝F1rt*KmfMeanwhile, the coal amount N of the thermal state unlocking point is calculatedmlrtjs＝Frtjs*Kmf；
4) When the fire is raised, namely after the fire suppression in the step 2) is finished and before the bed temperature is lower than 600 ℃, starting a fan, putting in fuel and quickly starting the boiler; all fans are automatically started in sequence, and the frequency F1 of the primary fan is increased until the primary air volume F1rtAchieve the thermal state unlocking air volume FrtjsIn the process, the frequency f1 of the primary air fan is stabilized, the coal feeder is automatically started, and the coal feeding quantity N is increasedmlAnd make the coal supply amount NmlThe coal quantity N corresponding to the thermal state unlocking point corresponding to the air quantity is reachedmlrtjsAt this time, the bed temperature rises according to the bed temperature TcwRate of rise kcwChange, wait for bed temperature TcwRising to above 650 ℃ and increasing the bed temperature at a rate kcwAlways kept at more than 3 ℃ per minute and contains oxygen O2The time delay is not increased for 3 seconds below 4 percent, the frequency f1 of the primary air fan is automatically increased at the moment, and the increasing process is carried out according to the bed temperature rising rate kcwChange if the rate of rise kcwIn a descending trend, the frequency f1 of the primary air fan stops rising, and the coal feeding quantity N is correspondingly increasedmlAccording to the air volume F1rtCorresponding coal quantity NmlIs automatically added to F1rt*KmfTo ensure the bed temperature TcwThe temperature of the bed is higher than 850 ℃, and the air quantity and the coal quantity are matched to the bed temperature rise rate kcwThe area is stable and does not exceed 1 ℃ per minute of fluctuation from top to bottom, and the fire is raised to work at the moment.
The working principle of the invention is as follows:
obtaining the air quantity of the circulating fluidized bed boiler in the cold state when the circulating fluidized bed boiler is unlocked through a boiler cold state test; when the boiler is in a hot-state operation state, finding out the air volume when the circulating fluidized bed boiler is in an 'unlocking phenomenon' in the hot state when the boiler is in a fire suppression time; the air quantity, the coal feeding quantity and the fan frequency parameter which correspond to the air quantity when the 'unlocking phenomenon' occurs to the circulating fluidized bed boiler in the thermal state are used as the automatic adjustment basis when the boiler raises fire, and in the fire raising process, the oxygen content and the bed temperature change rate are tracked through the automatic control of a computer, the air quantity and the coal feeding quantity are automatically adjusted, the automatic fire raising is realized, and the success rate and the stability of the fire raising are ensured.
The invention has the technical effects that:
the invention uses a computer to automatically record the air volume and the air chamber pressure value during the fire suppression, and carries out the slope calculation of the corresponding curve, and when the maximum slope occurs, the corresponding air volume is taken as the optimal air volume and is taken as the fluidized air volume during the fire raising starting; calculating the coal feeding amount according to the air quantity, taking the ratio of the air quantity to the coal feeding amount as a reference when the fan is started, and automatically feeding the calculated coal feeding amount after the fan is started; the optimal fluidization air quantity and the corresponding coal quantity are combined, so that the accumulated heat of the fire-pressing material layer is kept to the maximum extent, the heat brought by the new coal is supplemented in time, the material layer is ensured to be heated stably, and the success of fire raising is ensured. In the fire raising process of the circulating fluidized bed boiler, factors for taking away heat include air volume, circulating water volume, heat absorption before burning of coal as fired, heat taken away by circulating ash and the like, wherein the heat taken away by primary air is the largest. Because the bed temperature is lower at this moment, the primary air temperature is also low, if the primary air quantity is not controlled well, the air quantity is too large, a large amount of heat is taken away, and the bed temperature is rapidly reduced; meanwhile, if the coal feeding amount is not enough, the volatilization analysis output amount is small, the discharged heat is not enough to improve the bed temperature, the coal amount is too much, the heat absorption amount in the initial stage of entering the boiler is too large, the oxygen amount is not enough, the bed temperature is not suitable to rise, the coal entering the boiler can cause fire extinguishing due to insufficient temperature, only oil can be put into the boiler to support combustion, and accidents such as deflagration, coking and the like can be caused due to too much combustible gas accumulation in serious conditions, so that the safety and economic operation of the boiler are adversely affected. Aiming at the point, the optimal coal quantity and air quantity are obtained through experiments, and the success probability of boiler fire raising is improved through computer control. After the invention, the fire-raising starting is ensured, the accident risk of material layer coking is reduced, and the oil consumption of the fire-raising starting is saved. The invention provides the best fluidization air quantity for fire raising starting aiming at the actual working condition before fire suppression, and ensures the success of fire raising starting and the stable promotion of bed temperature.
Description of the drawings:
FIG. 1 flow chart of cold test
FIG. 2 is a flow chart of the thermal state fire suppression finding unlocking phenomenon
FIG. 3 is a flow chart of automatic fire raising
The specific implementation mode is as follows:
a method for improving the success rate and the starting stability of the boiler fire suppression restart by a computer comprises the following steps:
1) as shown in FIG. 1, in the cold fluidization test of the boiler, the flow rate of the primary air F was variedltIncrease of (2), plenum pressure PltIncrease correspondingly at the air quantity FltWhen the air speed reaches a certain value, the bed pressure drop reaches the maximum value which is slightly larger than the bed static pressure, if the air speed is continuously increased, the bed pressure drop is reduced to the bed static pressure, the phenomenon is called the unlocking phenomenon of the circulating fluidized bed boiler, and the air volume F during the unlocking phenomenon is recordedltjsAnd corresponding plenum pressure Pltjs；
2) As shown in fig. 2, after the boiler is started, the working condition of the boiler is changed from a cold state to a hot state, and when the boiler is subjected to a fire suppression, the working condition is as follows: the fluidized bed boiler cuts off fuel, stops the fan and stops the boiler from running in a short time; taking the parameter when the unlocking phenomenon occurs as a reference, and converting the primary air quantity FrtyhReducing the unlocking air quantity F to be less than that of the cold testltjsThen, the primary air quantity F is increasedrtyhAt the moment, the pressure Prtyh of the air chamber has a change trend of increasing, then decreasing and then increasing, namely an unlocking phenomenon point of thermal state fire suppression appears;
3) after finding the unlocking phenomenon point in the hot state, recording the hot state unlocking air quantity FrtjsAnd a thermal state unlocking pressure PrtjsThermal unlocking air quantity FrtjsAs the wind quantity when the fire is raised, and recording the current fan frequency frtAnd recording the ratio K of the coal quantity to the air quantity in normal and stable operationmf(ton/hour)/(cubic meter/hour) as the amount of coal corresponding to a certain air flow, i.e., the amount of coal Nml＝F1rt*KmfMeanwhile, the coal amount N of the thermal state unlocking point is calculatedmlrtjs＝Frtjs*Kmf；
4) As shown in fig. 3, when the fire is raised, namely after the fire suppression in the step 2) is completed, before the bed temperature is lower than 600 ℃, starting a fan, feeding fuel and quickly starting the boiler; all fans are automatically started in sequence, and the frequency F1 of the primary fan is increased until the primary air volume F1rtAchieve the thermal state unlocking air volume FrtjsIn the process, the frequency f1 of the primary air fan is stabilized, the coal feeder is automatically started, and the coal feeding quantity N is increasedmlAnd make the coal supply amount NmlThe coal quantity N corresponding to the thermal state unlocking point corresponding to the air quantity is reachedmlrtjsAt this time, the bed temperature rises according to the bed temperature TcwRate of rise kcwChange, wait for bed temperature TcwRising to above 650 ℃ and increasing the bed temperature at a rate kcwAlways kept at more than 3 ℃ per minute and contains oxygen O2The time delay is not increased for 3 seconds below 4 percent, the frequency f1 of the primary air fan is automatically increased at the moment, and the increasing process is carried out according to the bed temperature rising rate kcwVariations inIf the rate of rise kcwIn a descending trend, the frequency f1 of the primary air fan stops rising, and the coal feeding quantity N is correspondingly increasedmlAccording to the air volume F1rtCorresponding coal quantity NmlIs automatically added to F1rt*KmfTo ensure the bed temperature TcwThe temperature of the bed is higher than 850 ℃, and the air quantity and the coal quantity are matched to the bed temperature rise rate kcwThe area is stable and does not exceed 1 ℃ per minute of fluctuation from top to bottom, and the fire is raised to work at the moment.
Calculating the slope of a corresponding curve according to the air volume and the air chamber pressure value during fire suppression, and taking the corresponding air volume as the optimal air volume when the maximum slope occurs, and taking the optimal air volume as the fluidized air volume during fire raising starting; calculating the coal feeding amount according to the air quantity, taking the ratio of the coal feeding amount to the coal feeding amount as a reference when the fan is started, and automatically feeding the calculated coal feeding amount after the fan is started; the optimal fluidization air volume and the corresponding coal volume.
According to the invention, the air quantity parameter of the cold test is taken as a reference point, the lowest fluidization air quantity in the hot state is found out according to the air quantity parameter of the cold test during the hot state operation, the coal feeding quantity, the air quantity and the fan frequency corresponding to the lowest fluidization air quantity in the hot state are simultaneously collected, the air quantity and the coal feeding quantity are automatically adjusted according to the accurate and reliable parameter basis of the most-igniting start under the control of a computer according to the change trend of the bed temperature and the oxygen quantity, and the adjustment results greatly improve the success rate and the stability of the boiler ignition operation because of the reliable test parameters.

Claims (1)

1. A method for improving the success rate of boiler fire suppression restart and the starting stability by a computer is characterized by comprising the following steps:
1) and during the cold fluidization test of the boiler, the air quantity is changed along with the primary air quantity FltIncrease of (2), plenum pressure PltIncrease correspondingly at the air quantity FltWhen the wind speed reaches a certain value, the bed pressure drop reaches the maximum value which is slightly larger than the bed static pressure, if the wind speed is continuously increased, the wind speed is continuously increasedThe pressure drop of the bed layer is reduced to the static pressure of the bed layer, the phenomenon is called the unlocking phenomenon of the circulating fluidized bed boiler, and the air quantity F during the unlocking phenomenon is recordedltjsAnd corresponding plenum pressure Pltjs；
2) After the boiler is started to operate, the working condition of the boiler is changed from a cold state to a hot state, and when the boiler is subjected to fire suppression, the method comprises the following steps: the fluidized bed boiler cuts off fuel, stops the fan and stops the boiler from running in a short time; taking the parameter when the unlocking phenomenon occurs as a reference, and converting the primary air quantity FrtyhReducing the unlocking air quantity F to be less than that of the cold testltjsThen, the primary air quantity F is increasedrtyhAt the moment, the pressure Prtyh of the air chamber has a change trend of increasing, then decreasing and then increasing, namely an unlocking phenomenon point of thermal state fire suppression appears;
3) after finding the unlocking phenomenon point in the hot state, recording the hot state unlocking air quantity FrtjsAnd a thermal state unlocking pressure PrtjsThermal unlocking air quantity FrtjsAs the wind quantity when the fire is raised, and recording the current fan frequency frtAnd recording the ratio K of the coal quantity to the air quantity in normal and stable operationmf(ton/hour)/(cubic meter/hour) as the amount of coal corresponding to a certain air flow, i.e., the amount of coal Nml＝F1rt*KmfMeanwhile, the coal amount N of the thermal state unlocking point is calculatedmlrtjs＝Frtjs*Kmf；
4) When the fire is raised, namely after the fire suppression in the step 2) is finished and before the bed temperature is lower than 600 ℃, starting a fan, putting in fuel and quickly starting the boiler; all fans are automatically started in sequence, and the frequency F1 of the primary fan is increased until the primary air volume F1rtAchieve the thermal state unlocking air volume FrtjsIn the process, the frequency f1 of the primary air fan is stabilized, the coal feeder is automatically started, and the coal feeding quantity N is increasedmlAnd make the coal supply amount NmlThe coal quantity N corresponding to the thermal state unlocking point corresponding to the air quantity is reachedmlrtjsAt this time, the bed temperature rises according to the bed temperature TcwRate of rise kcwChange, wait for bed temperature TcwRising to above 650 ℃ and increasing the bed temperature at a rate kcwAlways kept at more than 3 ℃ per minute and contains oxygen O2Delay time of less than 4% for 3 seconds without risingAt the moment, the frequency f1 of the primary air fan is automatically increased, and the increasing process is carried out according to the bed temperature rise rate kcwChange if the rate of rise kcwIn a descending trend, the frequency f1 of the primary air fan stops rising, and the coal feeding quantity N is correspondingly increasedmlAccording to the air volume F1rtCorresponding coal quantity NmlIs automatically added to F1rt*KmfTo ensure the bed temperature TcwThe temperature of the bed is higher than 850 ℃, and the air quantity and the coal quantity are matched to the bed temperature rise rate kcwThe area is stable and does not exceed 1 ℃ per minute of fluctuation from top to bottom, and the fire is raised to work at the moment.
CN201910614709.3A 2019-07-09 2019-07-09 Method for improving success rate and starting stability of boiler fire suppression restart by computer Active CN110296436B (en)

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