JPH081295B2 - Sootblower control device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soot blower control device for controlling the operation of a soot blower installed in a boiler.

[0002]

2. Description of the Related Art In a coal fired boiler, pulverized pulverized coal is used as fuel coal. When the boiler is operated, pulverized coal is burned, and ash or soot adheres to the heat transfer surface of the boiler to reduce heat transfer efficiency.

For this reason, in large boilers, sometimes about 100 soot blowers are installed, and air and steam are ejected from the soot blowers to remove the adhered ash and soot. Conventionally, the operation of the soot blower installed in the boiler is empirically determined by the operator when the soot blower should be operated according to the degree of contamination, and the operation timing can be changed at regular intervals or when the heat collection rate decreases. It was done by adjusting.

[0004]

As described above, the operation of the conventional soot blower is performed by the operator operating according to the degree of contamination or adjusting the operation timing according to the decrease in the heat collection rate. It was

Therefore, when the operation time is long, the adhesion of ash is large and the heat transfer efficiency is lowered, so that the thermal efficiency of the boiler is lowered, and when a large number of soot blowers are operated in a short time, air or steam is injected into the furnace. As the temperature decreases, the unburned content in ash rises and the thermal efficiency decreases.

[0006] Further, the operation of the soot blower also changes the unburned content contained in the ash in the combustion exhaust gas discharged from the boiler and the NOx value in the exhaust combustion exhaust gas. For this reason, it was not possible to operate the soot blower in which the unburned ash concentration and the NOx value in the discharged ash were within constant values and the thermal efficiency was the highest.

According to the present invention, the concentration of unburned matter in the discharged ash, N
An object of the present invention is to provide a soot blower control device that keeps the Ox value within a constant value and controls the operation of the soot blower that maximizes thermal efficiency.

[0008]

Means adopted by the present invention to solve the above problems will be described with reference to the principle of FIG. In a soot blower control device for a boiler having a plurality of soot blowers installed, an operation history recording means 1 for recording a past operation history of the soot blower, and a contamination degree judging means for judging that the temperature difference between the inner and outer walls of the furnace metal is out of a specified value Two
And the number determined by the stain degree determination means 2 to be outside the specified value,
A function recording means 3 for recording a membership function for the furnace heat collection rate, ash unburned matter concentration and load, and a soot blower injection time interval are inferred by fuzzy inference from the grade value from the function recording means 3 and output. The fuzzy inference means 4 and the priority of the soot blower to inject from the furnace metal temperature difference measurement position determined to be out of the specified value by the contamination degree determination means 2 and the past operation history of the soot blower recorded in the operation history recording means 1 And an injection position determining means 5 for determining the order.

[0009]

The operation history recording means 1 records the operation history of the soot blower that has been operated in the past. Dirt degree determination means 2
Then, it is determined whether the temperature difference between the inner and outer walls of the furnace metal is other than the specified value.

The function recording section 3 corresponds to the furnace heat collection rate of the boiler, the concentration of unburned components discharged, the load, and the number of the furnace metal temperature difference outside the specified value in the fouling degree judging means 2. Membership function is recorded. In the fuzzy inference means 4, the furnace heat collection rate, the unburned ash concentration, the load,
And the soot blower injection time interval is deduced from the number outside the specified value of the dirt level and output.

Further, in the injection position determining means 5, the injection position of the soot blower recorded in the furnace metal temperature difference measuring position and the operation history recording means 1 which is out of the specified value in the contamination degree determining means 2 is recorded. The injection soot blower position is determined from the operation history and output.

As described above, the soot blower injection time interval and the furnace metal temperature difference specified by fuzzy inference based on the furnace heat collection rate, the unburned ash concentration, the load, and the number outside the specified furnace metal temperature difference. Since the next soot blower injection position is output from the out-of-value position and the past soot blower operation history, the soot blower is controlled so that the concentration of unburned ash in the ash and NOx values are kept within the specified values and the thermal efficiency is optimized. be able to.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. 2 is a configuration diagram of an embodiment of the present invention, FIG. 3 is an operation flowchart of the embodiment, and FIG. 4 is an inference explanation diagram in a fuzzy inference unit of the embodiment.

In FIG. 2, reference numerals 11 to 14 are interfaces (I / O) to which the furnace heat collection rate from the boiler, the unburned ash concentration, the load, and the temperature difference between the inner and outer walls of the furnace metal are input. . 15 is also I / O,
Output data is output. 16 is a driving history recording section,
Reference numeral 17 is a dirt degree determination unit, 18 is a membership function unit, and 19
Is a fuzzy rule unit, 20 is a fuzzy inference unit, 21 is an injection position determination unit, 22 is a recording unit, and 23 is a microprocessor (CPU).

The driving history recording unit 16 records the driving history of the soot blower that has been driven in the past. The contamination degree determination unit 17 determines whether or not the temperature difference between the inner and outer walls of the furnace metal input from the I / O 14 is out of the specified value. Based on experience and experiments, the membership function unit 18 has a furnace metal heat ratio, an unburned ash concentration in the ash, a load and a degree of contamination of the furnace metal which are out of the specified values as shown in FIG. 4 in advance. The membership function for the number of temperature differences is recorded.

In the fuzzy rule section 19, the fuzzy rules indicated by if-then-which are inferred by the fuzzy inference section 20 are recorded. The fuzzy reasoning unit 20 follows the fuzzy rules recorded in the fuzzy rule unit 19 to collect data on the heat collection rate of the furnace, the concentration of unburned ash in the ash, the load, and the temperature of the outside-specified furnace metal temperature, and the membership function recording unit. Fuzzy inference is performed from the data recorded in 18, and the soot blower injection time interval is inferred and output.

FIG. 4 shows C from the input values A _t and B _t.
A case where the value _t is calculated by fuzzy inference will be described as an example. In FIG. 4, A, B and C are aggregates respectively, S _A , M _A and L _A are fuzzy sets in set A, and S _B , M _B and L _B are sets B.
Fuzzy _{set, C 1, C 2, C} 3 and C ₄ are fuzzy sets in the set C, which are stored in the membership function unit as a membership function in.

The fuzzy rule section stores a fuzzy set of C corresponding to each fuzzy set of A and B.
_{That, if (A = M A,} B = M B) then (C = C 1) if (A = M A, B = L B) then (C = C 3) if (A = L A, B = M _{B) then (C = C 2} ) if (a = L a, B = L B) then (C = C 4) such rules are stored.

The inference first examines which fuzzy set the input values A _t and B _t belong to. To A _t is M _A and L _A is the case in FIG. 4, also B _t belongs to M _B and L _B. Next, as shown in FIGS. 4A to 4D, A =
Four kinds of membership functions C _{1 to} C ₄ corresponding to the combination of M _A and L _A and B = M _B and L _B are read according to the fuzzy rule.

Next, the read membership function C ₁ ~
Each C _4, to cut the head with the smaller width of grade values for A _t and B _t. Next, FIG. 4 (e)
As shown in, the cut C _{1 to} C ₄ are overlapped,
The on-axis value C ₁ of the center of gravity is calculated and used as the inferred value.

In the description, the set is A, B and C, but
In the example, the heat collection rate of the furnace, the concentration of unburned matter in the ash, the load, and the number outside the specified value of the furnace metal are collected. That is, in the fuzzy inference unit 20, as shown in FIGS. 4A, 4B, 4C, and 4D, each membership function is cut by the data value, and these cut membership functions are As shown in FIG. 4 (e), they are superposed and integrated, and the position of their center of gravity is calculated and output as an inference result.

Next, the operation of the embodiment will be described with reference to FIG. Process S1 In process S1, from I / O 11 to 14, the furnace heat collection ratio,
The unburned ash concentration, load, and furnace metal temperature difference data are read and recorded in the recording unit 22.

Process S2 In process S2, the degree-of-dirt determination unit 17 reads the furnace metal temperature difference data recorded in the recording unit 22, determines whether the temperature difference is outside the specified value, and determines whether the temperature difference is outside the specified value. The number and the number of points are recorded in the recording unit 22.

Process S3 In process S3, the fuzzy inference unit 20 follows the fuzzy rule recorded in the fuzzy rule unit 19 and records the furnace heat collection rate, the unburned ash concentration in the ash, the load and By reading the specified temperature outside furnace metal temperature difference number data and the data recorded in the membership function section 18, the unburned ash concentration and NOx value are within the specified values, and the efficiency of the boiler is optimally maintained. The soot blower operating time interval is estimated and output from the I / O 15.

Process S4 In process S4, the injection position determination unit 21 causes the furnace metal temperature difference position outside the specified value recorded in the recording unit 22 and the past soot blower operation history recorded in the operation history recording unit 16. The position of the soot blower to be driven next time is determined and output from the I / O 15.

As a method of determining the soot blower position, for example, the number of soot blowers to be injected is determined in advance, and the vicinity of the furnace metal temperature difference detection point which is out of the specified value in the contamination degree determination unit 17 is targeted, and the operation history recording unit is used. The injection positions are determined in order from the oldest injection history recorded in 16.

This position determination is an example, and the present invention is not limited to this embodiment, and various modifications can be made. Process S5 In process S5, when the sootblower at the position determined in process S4 is operated, the position and time are recorded in the operation history recording unit 16.

[0028]

As described above, according to the present invention, the following effects can be obtained. The soot blower injection time interval was determined by fuzzy reasoning based on the furnace heat collection rate, ash unburned matter concentration, load, and the number outside the specified furnace metal temperature difference, and the position outside the specified furnace metal temperature difference and past soot blower operation. Since the next soot blower injection position is output from the history, the soot blower can be controlled so that the concentration of unburned matter in the ash and the NOx value are within the specified values and the thermal efficiency is optimized.

[Brief description of drawings]

FIG. 1 is a principle diagram of the present invention.

FIG. 2 is a configuration diagram of an embodiment of the present invention.

FIG. 3 is an operation flowchart of the same embodiment.

FIG. 4 is an explanatory diagram of inference by a fuzzy inference unit according to the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Driving history recording means 2 Fouling degree determination means 3 Function recording means 4 Fuzzy inference section 5 Injection position determination means 11-15 Interface (I / O) 16 Driving history recording section 17 Fouling degree determination section 18 Membership function section 19 Fuzzy rule Part 20 Fuzzy inference part 21 Injection position determination part 22 Recording part 23 Processor (CPU)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshihiro Takano 2-4-25 Minamisuna-cho, Koto-ku, Tokyo Kawasaki Heavy Industries Ltd. Tokyo Design Office

Claims (1)

[Claims] 1. A soot blower control device for a boiler having a plurality of soot blowers, wherein an operation history recording means 1 for recording a past operation history of the soot blower and a temperature difference between an inner wall and an outer wall of a furnace metal are determined to be outside a specified value. And a function recording means 3 for recording a membership function with respect to the number, the heat collection rate of the furnace, the concentration of unburned ash in the ash, and the load, which is determined to be outside the specified value by the contamination degree determining means 2. Fuzzy inference means for inferring and outputting the soot blower injection time interval by fuzzy inference based on the grade value from the function recording means 3, and the furnace metal temperature difference measurement position determined by the contamination degree determination means 2 to be out of the specified value, and Injection position determination for determining the priority of soot blowers to be injected based on the past operation history of soot blowers recorded in the operation history recording means 1. Sootblower control apparatus characterized by comprising a stage 5.