JP3018039B2 - Soot blower activation control method and device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a soot blower start control method and apparatus, and more particularly, to a soot blower suitable for controlling the start of a soot blower for cleaning the inside of a furnace of a boiler for thermal power generation. The present invention relates to a soot blower activation control method and device.

[Conventional technology]

It is necessary for a boiler for thermal power generation to always keep the inside of a furnace clean and prevent the boiler efficiency from decreasing.
Therefore, in order to clean dirt in a furnace, a soot blower for cleaning a furnace wall, a soot blower for cleaning a superheater, and a soot blower for cleaning a reheater are used as auxiliary boilers.

Conventionally, when starting each soot blower, a method of operating the soot blower at the discretion of the exerciser or operating the soot blower at regular time intervals has been adopted. However, in this method, the soot blower may be started irrespective of dirt in the furnace, and there is a problem that steam injected from the soot blower is wasted and the furnace wall is worn.

Therefore, as described in the Thermal Nuclear Power Generation (Quartz Boiler Combustion Management System) Vol.38 No.2, published in February 1987, the start-up schedule of the soot blower was determined using a model that predicts the contamination of the heat transfer surface of the boiler. A method has been proposed in which a soot blower activation schedule is determined based on a knowledge base, or as described in JP-A-63-286608.

[Problems to be solved by the invention]

In the above prior art, it is not considered that the fouling in the furnace has an ambiguous point due to the type of heating material, operating conditions, aging, and the like. Even if a model or knowledge base is created, it may not be possible to accurately evaluate the dirt in the furnace.

SUMMARY OF THE INVENTION An object of the present invention is to provide a soot blower activation control method and apparatus capable of controlling the activation of a soot blower by accurately evaluating dirt in a furnace even when there is an ambiguity regarding dirt in the furnace. .

[Means for solving the problem]

In order to achieve the above object, the present invention provides, as a first method, when starting a soot blower for cleaning a water cooling wall in a furnace of a boiler for thermal power generation, when starting a dirt on the water cooling wall in the furnace. Along with inputting process data related to the superheater based on fuzzy inference from the data of the superheater spray flow rate change amount among the input process data, input time data indicating an elapsed time after the start of the soot blower for water cooling wall cleaning. While calculating the certainty factor for the spray flow rate change amount, calculating the certainty factor for the elapsed time after the start of the soot blower for water cooling wall cleaning based on the fuzzy inference from the input time data, and calculating the center of gravity position from the calculated certainty factor. The dirt on the water cooling wall is evaluated from the position of the center of gravity, and the activation of the water cooling wall cleaning soot blower is controlled according to the evaluation. Sootblower start control method for a constitution that the adopted.

As a second method, when starting the soot blower for cleaning the superheater of the boiler for thermal power generation, while inputting process data relating to contamination of the superheater, and inputting time data indicating an elapsed time after starting the soot blower for cleaning the superheater,
Among the input process data, the degree of certainty for the superheater spray flow rate change is calculated based on the fuzzy inference from the data of the superheater spray flow rate change, and the superheater cleaning is performed based on the fuzzy inference from the input time data. The degree of certainty with respect to the elapsed time after the start of the soot blower is calculated, the position of the center of gravity is obtained from the calculated degree of certainty, dirt on the superheater is evaluated from the position of the center of gravity, and the start of the soot blower for cleaning the superheater is controlled according to the evaluation. The soot blower activation control method is adopted.

As a third method, when starting the soot blower for cleaning the reheater of the boiler for thermal power generation, process data relating to contamination of the reheater is input, and time data indicating the elapsed time after the start of the soot blower for cleaning the reheater is input. type in,
Among the input process data, the confidence level for the GRF damper opening change is calculated based on the fuzzy inference from the data of the GRF damper opening change, and the reheater cleaning is performed based on the fuzzy inference from the input time data. Calculates the degree of certainty for the elapsed time after starting the soot blower,
A soot blower activation control method for controlling the activation of the reheater cleaning soot blower according to the evaluation, determining the center of gravity position from the calculated certainty factor, evaluating the dirt on the reheater from the center of gravity position, and evaluating the evaluation. is there.

Further, the present invention provides a process data input means for inputting process data relating to dirt in a furnace of a thermal power generation boiler, and a time data input for inputting time data indicating an elapsed time after activation of a soot blower arranged in the furnace. Means for calculating confidence in the superheater spray flow rate change based on the fuzzy inference from the data of the superheater spray flow rate change in the process data, and the elapsed time after the start of the soot blower based on the fuzzy inference from the time data. Means for calculating a certainty factor for the center of gravity, a center of gravity position calculating means for calculating the position of the center of gravity from the calculated certainty factor, and a dirt for evaluating dirt in the furnace from the position of the center of gravity calculated by the center of gravity calculating means. Evaluation means, and activation control means for controlling activation of the soot blower in accordance with the evaluation of the dirt evaluation means; It is obtained by constituting the soot blower activation control apparatus having.

[Operation] During the operation of the boiler, process data relating to dirt in the furnace is input, and time data indicating an elapsed time after the start of the soot blower arranged in the furnace is input. Quantity or
Based on fuzzy inference from data on the GRF damper opening change, calculate the certainty for the superheater spray flow rate change or GRF damper opening change, and based on the fuzzy inference from time data, belief about the elapsed time after sootblower startup. Is calculated, the position of the center of gravity is calculated from the calculated certainty factor, and the contamination in the furnace is evaluated from the position of the center of gravity.
Even when the boiler has ambiguity due to a change over time, it is possible to accurately evaluate the contamination in the furnace from the position of the center of gravity of the certainty factor. Therefore, by controlling the start of the soot blower based on this evaluation, it becomes possible to control the start of the soot blower in accordance with dirt in the furnace.

〔Example〕

 Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

In FIG. 1, a water cooling tube 14, a superheater 16, and a reheater 18 are provided in a furnace 12 of a thermal power generation boiler 10. The water cooling pipe 14 is buried in the furnace wall of the furnace 12 and a water supply pump 20
Is supplied with water. The water cooling pipe 14 is connected to the superheater 16, and a pipe 22 branched from a pipe connecting the water cooling pipe 14 and the superheater 16 is provided with a control valve 24 for controlling a spray flow rate of the superheater 16. Superheater from this pipe 22
Steam is injected into the heater 16, and the spray flow rate of the superheater 16 is controlled by the opening of the control valve 24.
The temperature of 16 is adjusted. The superheater 16 is connected to the high-pressure turbine 26, and the reheater 18 is connected to the high-pressure turbine 26 and the low-pressure turbine 28. A GRF damper (not shown) for controlling the exhaust gas recirculation amount is provided in the vicinity of the reheater 18 so that the temperature of the reheater 18 is adjusted by the opening degree of the GRF damper. Has become. A soot blower 30 for cleaning the furnace wall of the furnace 12, a soot blower 32 for cleaning the superheater 16, and a soot blower 34 for cleaning the reheater 18 are provided on the furnace wall of the furnace 12.
Is slidably installed. The various process data 100 associated with the operation of the boiler 10 are input to the boiler control device 36. The boiler control device 36 controls the amount of fuel and the amount of water supplied to the boiler 10 or controls the opening of the GRF damper and the control valve 24 according to the operation and program of the operator.
The degree of opening of the vehicle is controlled. As the process data 100, signals from various sensors (not shown) for detecting the process data 100, such as a feed water flow rate, a fuel flow rate, a GRF damper opening degree, and a gas temperature of the furnace 12, are input. The boiler control device 36 is connected to a soot blower activation control device 40 via a unit network 38, and the process data 100 is transferred to the soot blower activation control device 40 via the unit network 38.

The soot blower activation control device 40 includes a controller (not shown) for performing various controls based on process data, and includes a CRT 42 and a keyboard 44. The soot blowers 30, 32, and 34 are started by the generated start command 102. The controller is composed of a microcomputer having a CPU, a RAM, a ROM, an I / O, and the like. This microcomputer substantially constitutes process data input means, confidence calculation means, dirt evaluation means, and start control means. It is supposed to. Specifically, as shown in FIG. 2, the controller includes a process data input unit 46, a classifying unit 48, a fuzzy inference unit 50, an inference result evaluation unit 52, a soot blower activation schedule creating unit 54, a soot blower activation command unit. It consists of 56.

Hereinafter, a method of creating a soot blower activation schedule by fuzzy inference using various process data will be described with reference to FIG.

The unit network 38 is connected to the process data input section 46.
Process data is inputted through the soot blower activation schedule creating unit 54, soot blowers 30, 3
Time data has been input after the elapse of 2,34 startups. When these data are transferred to the classifying unit 48, each data is classified in association with the soot blowers 30, 32, and 34.
The various data classified are transferred to the fuzzy inference unit 50 and are converted into certainty data for each class.

When converting various data into certainty data, as shown in FIG. 3, it is converted into certainty data based on certainty map data stored in advance in the ROM. According to the fuzzy inference, these map data are based on the confidence in the amount of change in the superheater spray flow, the confidence in the change in the opening of the GRF damper, the confidence in the elapsed time after the start of the superheater soot blower, and the confidence in the elapsed time after the start of the reheater soot blower The data of the degree of certainty with respect to the elapsed time after the activation of the water cooling wall soot blower is stored in the ROM in advance. Various input data are converted into certainty data based on the certainty map data. The superheater spray flow rate change indicates the change from the time when the soot blower 30 or 32 is started, and the GRF damper opening change indicates the change from the time when the soot blower 30 or 34 is started. Also, it is better not to consider the amount of change while the temperature of each part is stabilized after the start of the soot blower. Further, since the characteristics of the relationship between the certainty factor data and each process data differ depending on the plant, it is desirable to make adjustments at the time of trial operation or the like.

Next, when evaluating the contamination of the water cooling wall (furnace wall of the furnace 12), the superheater 16 and the reheater 18 from the confidence data, the ROM
Is evaluated using the inference rules stored in the.

Water cooling wall dirt inference rule Elapsed time after activation of water cooling wall soot blower (B) * Positive change in superheater spray flow rate (P) then Large water cooling wall stain During elapsed time after activation of water cooling wall soot blower (M) * Change in superheater spray flow rate Zero (Z) then Water cooling wall dirty Medium elapsed time after water cooling wall soot blower started (S) * Superheater spray flow rate change negative (N) then Water cooling wall dirty small Superheater dirty inference rule Large elapsed time after starting superheater soot blower B) * Negative change in superheater spray flow rate (P) then Large amount of superheater dirt Elapsed time after starting superheater soot blower (M) * Zero superheater spray flow change (Z) then Superheater dirty During superheater soot blower startup Elapsed time is small (S) * Superheater spray flow rate change is large (N) then Superheater dirt is small Reheater dirt inference rule Elapsed time is long after reheater soot blower starts (B) * GRF damper opening change Positive amount (P) then Superheater dirt large Elapsed time after starting reheater soot blower (M) * Zero GRF damper opening change (Z) then Superheater dirt Small elapsed time after reheater soot blower started (S * GRF damper opening change negative (N) then Superheater dirt small
Although the certainty of the change of the superheater spray flow rate and the elapsed time of starting the water wall soot blower (30) were used, depending on the plant, the certainty of the GRF damper opening change amount may be used instead of the superheater spray flow change amount. Is also possible.

Next, an example in which the inference result evaluation unit 52 evaluates dirt by fuzzy inference using inference rules will be described with reference to FIG.

For example, when evaluating the contamination of the water cooling wall, first, from the process data and the time data, the amount of change in the superheater spray flow rate is X, and the elapsed time after the activation of the water cooling wall soot blower (30) is Y
Is obtained, the certainty factor data x1, x2, y1, y2 are calculated based on the map data. Among these certainty data, certainty data having a low certainty is selected, and dirt on the water cooling wall is evaluated based on the selected certainty data x2 and y1. And when evaluating the dirt on the water cooling wall from this confidence data,
As shown in FIG. 4 (C), the position of the center of gravity u of each certainty factor data is obtained, and the position of the center of gravity u is determined as the degree of contamination u of the water cooling wall.
(%).

The contamination degree of the superheater 16 and the reheater 18 can be evaluated by the same method.

When the dirt level is evaluated, the value of the dirt level is transferred to the soot blower activation schedule creating unit 54,
It is determined whether the soot blowers 30, 32, 34 need to be activated. For example, a threshold value is set for the degree of contamination of each part, and the soot blower can be activated only when the degree of contamination exceeds the threshold value. When starting each soot blower,
A method of starting the soot blower in descending order of the degree of contamination can be adopted. Furthermore, it is also possible to determine the start-up time of each soot blower 30, 32, 34, etc. according to the degree of contamination. It is also possible to provide superheaters 16 on the left and right sides of the furnace 12 for the superheater 16, evaluate the spray flow rates of these superheaters separately, and evaluate the imbalance of dirt on the left and right of the superheater. In this case, it is necessary to control the activation of the soot blower so as to eliminate imbalance.

When the soot blower activation schedule creating section 54 creates an activation schedule for each soot blower, the soot blower activation instruction section 56 outputs a soot blower activation instruction 102 according to the activation schedule. As a result, the soot blowers 30, 32, and 34 started up, and the water cooling wall, superheater 16, and reheater
18 cleanings are performed.

According to the present embodiment, the process data is converted into certainty data based on fuzzy inference, so that the dirt of each part is evaluated from the certainty data, even if the dirt in the furnace 12 has ambiguity, Dirt of each part in the furnace 12 can be accurately evaluated, and the start-up of each soot blower 30, 32, 34 can be controlled according to this evaluation.

In the above embodiment, if the inference result is displayed on the CRT 42 or the soot blower activation threshold is adjusted by operating the keyboard 44, the man-machine property can be improved. Further, when the contamination is evaluated, if the turbine load is actually changed in operation, the operation obstacle can be eliminated by providing the inference result with a constraint condition such as invalidity.

〔The invention's effect〕

As described above, according to the present invention, dirt in the furnace is evaluated based on fuzzy inference, and the soot blower is started according to the evaluation. Therefore, even when the dirt in the furnace has ambiguity, the soot blower can be used. Startup can be controlled precisely according to the dirt in the furnace,
The heat absorption efficiency of the boiler can always be maintained in an optimum state, which can contribute to a reduction in fuel consumption and can increase the operating efficiency of the soot blower.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, FIG. 2 is a specific block diagram of a soot blower activation control device, FIG. 3 is a characteristic diagram showing the degree of certainty with respect to process data, and FIG. It is a figure for explaining the method of evaluating the dirt degree of a water cooling wall. 10 …… boiler, 12 …… furnace, 14 …… water-cooled tube, 16 …… superheater, 18 …… reheater, 20 …… supply pump, 24 …… control valve,
26 …… High pressure turbine, 28 …… Low pressure turbine, 30,32,34…
... soot blower, 36 ... boiler control device, 40 ... soot blower activation control device.

Continuation of the front page (56) References JP-A-64-41712 (JP, A) JP-A-1-151700 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F23J 3 / 00

Claims (4)

(57) [Claims] When starting a soot blower for cleaning a water cooling wall in a furnace of a boiler for thermal power generation, process data relating to dirt on the water cooling wall in the furnace is inputted, and the water cooling wall is cleaned. Time data indicating the elapsed time after starting the soot blower is input, and the confidence level for the superheater spray flow rate change is calculated based on fuzzy inference from the data of the superheater spray flow rate change data among the input process data, From the input time data, calculate the certainty factor with respect to the elapsed time after starting the soot blower for water cooling wall cleaning based on fuzzy inference, determine the position of the center of gravity from the calculated certainty factor, and evaluate the dirt on the water cooling wall from the position of the center of gravity. A soot blower activation control method for controlling activation of the water cooling wall cleaning soot blower according to the evaluation. 2. When the soot blower for cleaning the superheater of the boiler for thermal power generation is started, process data relating to contamination of the superheater is input, and time data indicating an elapsed time after the start of the soot blower for cleaning the superheater is input. Among the input process data, the degree of certainty for the superheater spray flow rate change is calculated based on the fuzzy inference from the data of the superheater spray flow rate change, and the soot blower for superheater cleaning based on the fuzzy inference from the input time data. The degree of certainty with respect to the elapsed time after the start is calculated, the position of the center of gravity is obtained from the calculated degree of certainty, the contamination of the superheater is evaluated from the position of the center of gravity, and the start of the soot blower for cleaning the superheater is controlled according to the evaluation. Soot blower start control method. 3. When starting the soot blower for cleaning the reheater of the boiler for thermal power generation, process data relating to contamination of the reheater is input, and time data indicating the elapsed time after the start of the soot blower for cleaning the reheater is input. Calculating the certainty factor for the GRF damper opening change amount based on the fuzzy inference from the data of the GRF damper opening change amount in the input process data, and reheating based on the fuzzy inference from the input time data. The degree of certainty with respect to the elapsed time after starting the soot blower for cleaning the appliance is calculated, the position of the center of gravity is obtained from the calculated degree of certainty, and the dirt on the reheater is evaluated from the position of the center of gravity. A soot blower activation control method for controlling the activation of a soot blower. 4. Process data input means for inputting process data relating to contamination in a furnace of a thermal power boiler;
Time data input means for inputting time data indicating the elapsed time after the start of the soot blower disposed in the furnace; and superheater spray flow rate change based on fuzzy inference from the superheater spray flow rate change data among the process data. A certainty factor calculating means for calculating the certainty factor for the quantity, and calculating the certainty factor for the elapsed time after the start of the soot blower based on the fuzzy inference from the time data; and a center of gravity position for calculating the center of gravity position from the calculated certainty factor. A soot blower activation control device comprising: a calculation unit; a dirt evaluation unit that evaluates dirt in the furnace from the position of the center of gravity calculated by the centroid position calculation unit; and a start control unit that controls activation of the soot blower in accordance with the evaluation of the dirt evaluation unit.