JPH1122933A - Combustion control method and apparatus for rotary grating furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effect automatic control of combustion for a long period of time, by accurately carrying out a control for stabilizing position of a center of gravity of a flame within a constant range, without regard to fluctuations of refuse layer in a rotary grating furnace and calorific value of refuse. SOLUTION: An interior of a grate furnace body 1 is imaged by a TV camera 17 and its signals are processed by an image processor 18, in order to measure a center 16c of gravity of a flame 16 from coordinates in a circumferential direction and a longitudinal direction. If difference is detected between a measured position of the center of gravity of the flame and a reference point, fuzzy operation is carried out by a fuzzy control arithmetic unit so as to nullify the difference. Values of membership functions of circumferential direction burning index and longitudinal direction burning index are combined to infer rotational speed of a rotary grate furnace, and a center of gravity of inference result is derived by a center-of-gravity method and extracted as an adjustment amount of rotational speed, and the rotational speed of the rotary grate furnace is regulated so as to control combustion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for controlling the combustion of a rotary grate furnace for controlling the refuse combustion state of a rotary grate furnace for incineration of municipal solid waste and the like to a certain range. It is.

[0002]

2. Description of the Related Art In a rotary grate furnace, a large number of water tubes 4 are circumferentially arranged at regular intervals between an inlet header tube 2 and an outlet header tube 3, as schematically shown in FIG. The two ends of each water pipe 4 are connected to the inlet header pipe 2 and the outlet header pipe 3 so as to communicate with each other.
A furnace wall plate provided with a large number of air holes is attached therebetween to form a cylindrical grate furnace main body 1, and the grate furnace main body 1 is rotatably housed in a cover casing 5, and is provided on an outlet side. The header tube 3 is placed sideways at an angle so as to be lower, and the tires 6 are attached to the outer periphery of the entrance side and the exit side of the grate furnace main body 1, respectively. The grate furnace main body 1 is placed on the grate furnace body 1 by rotating one of the turning rollers 7 by the motor 8.
Is rotated, and further, a wind box 9 is installed below the grate furnace main body 1 so that air is introduced from the wind box 9 through the wall of the grate furnace main body 1, and The refuse 11 put in from the connected hopper 10 is put into the grate furnace main body 1 by the pusher device 12, and the refuse 11 is incinerated while rotating the grate furnace main body 1.

[0003] 13 is a post-combustion device, 14 is a secondary combustion chamber, 1
Reference numeral 5 denotes a universal joint connected to the outlet header pipe 3 so as to circulate and circulate boiler water in the water pipe 4.

When incinerating refuse in a rotary grate furnace having such a configuration, harmful dioxin may be generated if the incineration temperature of the refuse is unstable and incomplete combustion occurs.

[0005] Therefore, in the incineration of refuse, a device is devised to surely and stably burn the refuse.

Conventionally, in incineration of refuse in a grate furnace main body 1 of a rotary grate furnace, one of the scales for knowing the combustion state of refuse is 1
One is to measure the burn-out point,
A method has been proposed in which the position of the burn-off point is located within the grate furnace main body 1 and controlled using fuzzy theory so as to stabilize the position of the burn-off point.

That is, as shown in FIG. 9, in the incineration of the refuse 11 in the grate furnace main body 1, when the place where the flame 16 is generated is in the range shown by oblique lines, the burn-off point which is the lowest point of the flame 16 The position of the burn-out point 16a is measured in the longitudinal direction (upstream / downstream direction) in the grate furnace main body 1 and the position of the burn-out point 16a is rotated using fuzzy theory so that the position of the burn-out point 16a is stabilized in a certain portion. The control of the number of rotations of the grate furnace, the control of the supply amount of the refuse 11 into the grate furnace, and the like are performed.

[0008]

[0009] However, FIG.
The measurement of the burn-off point 16a shown in Fig. 4 is based on the premise that the waste quality and the waste layer become uniform. Actually, the waste level is not uniform due to the unevenness of the waste layer and the increase in the calorie of the waste quality. As shown in FIG. 10, a change occurs in the spread of the debris in the bed and the furnace, and as shown in FIG. 10, when the combustion becomes poor, the circumferential distance of the burn-off point 16a is the same as that in FIG. To move to the right, measuring only the longitudinal distance of the furnace as the burn-off point, it is not possible to accurately grasp the combustion situation, and it is not possible to reflect the conventional combustion quality information based on the burn-off point in the control system, There is a problem.

Accordingly, the present invention measures the position of the center of gravity of the flame not only in the longitudinal direction in the grate furnace but also in the circumferential direction instead of measuring the burn-out point which is the lowest point of the flame. ,
Follow the garbage thick layer and the change in garbage calorie accurately,
The purpose of the present invention is to improve the accuracy of combustion quality so as to improve control accuracy and achieve long-term automatic control of combustion.

[0010]

According to the present invention, in order to solve the above-mentioned problems, air is introduced from below into a grate furnace main body, and the refuse supplied thereto is incinerated while rotating the grate furnace main body. The position of the center of gravity of the flame of the grate furnace main body in the rotary grate furnace is determined from the coordinates in the longitudinal direction and circumferential direction of the main body of the grate furnace. In order to obtain stable combustion within a certain range, the value of each membership function of the circumferential burning index and the longitudinal burning index is calculated by fuzzy calculation for all fuzzy rules. , And then calculate the center of gravity of the inference result obtained by synthesizing the membership function of the rotating grate furnace rotation speed by the center of gravity method. Times A method and apparatus for adjusting the combustion control of the number, the fuzzy rules, the circumferential burning way indicator large,
A plurality of items are created by combining medium, small, and large, medium, and small indices on how to burn in the longitudinal direction, and the rotational speed of the rotating grate furnace is inferred for each item.

Since the position of the center of gravity of the flame can be determined not only in the longitudinal direction but also in the circumferential direction, the position of the center of gravity can be made to accurately follow fluctuations in the thickness of the garbage layer and the calories of the garbage. The accuracy of the judgment is improved.

Further, the accuracy of the adjustment amount can be improved by simultaneously synthesizing the values of the membership functions of the circumferential burning index and the longitudinal burning index for each fuzzy rule.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. In the rotary grate furnace having the same structure as the rotary grate furnace shown in FIG. ITV camera 1 for imaging the inside of the furnace from downstream to upstream
And an image processing apparatus 1 for processing image signals of the combustion state of the refuse in the grate furnace main body 1 captured by the camera 17
8 is set, and the point of the highest luminance of the flame 16 processed by the image processing device 18 is taken as the center of gravity 16c, and fuzzy inference is performed so that the position of the center of gravity 16c of the flame 16 is stabilized in a certain range. Fuzzy control arithmetic unit 1 that performs
The fuzzy control arithmetic unit 19 issues a rotation speed correction command to the motor 8 to adjust the rotation speed of the rotary grate furnace.

In FIG. 1, the same components as those in FIG. 8 are denoted by the same reference numerals.

The image processing device 18 regards the point where the luminance of the flame 16 is the highest as the center of gravity 16c, and determines the center of gravity 16c of the flame as the area of the flame 16 and the grate furnace main body 1c.
Is obtained from the coordinates in the longitudinal direction and the circumferential direction, and the position of the center of gravity 16c is detected in the circumferential direction and the position in the longitudinal direction is detected to measure the burning index a in the circumferential direction and the burning index b in the longitudinal direction. Is what you do.

As shown in the block diagram of FIG. 2, the fuzzy control arithmetic unit 19 includes indices a and b in the circumferential and longitudinal directions of the center of gravity 16c measured by the image processing unit 18, and
An addition point 20 for calculating a deviation between a reference value (a set value of how to burn) as a range in the circumferential direction and a longitudinal direction in which the center of gravity 16c is settled, and a fuzzy calculation unit for inferring the rotation speed of the rotary grate furnace. 21, an addition point 25 for adding the rotation speed adjustment amount of the rotary grate furnace and the rotation speed set value 24 of the rotary grate furnace obtained by the fuzzy calculation unit 21;
The apparatus includes a rotary controller 26 of a rotary grate furnace and a control object (rotary grate furnace) 27. The fuzzy calculation unit 21 performs fuzzy calculation according to fuzzy rules covering nine items for each detected value of the position of the center of gravity. Rule section 22
And a fuzzy synthesizing unit 23 for calculating the center of gravity of the inference result obtained by synthesizing the rotational speed of the rotary grate furnace calculated by the rule unit 22 and calculating the rotational speed adjustment amount.

The fuzzy rules of nine items indicating the relationship between the burning index a and the burning index b based on the position of the center of gravity of the flame and the rotation speed c of the rotary grate furnace associated therewith are as follows. It is as follows. If a is large (PB) and b is large (PB), c remains the same (NN) If a is large (PB) and b is medium (NN), c is lowered (NB) a is large In (PB), if b is small (NB), c is lowered (NB) a is medium (NN), if b is large (PB), c is raised (PB) a is medium (NN) , If b is medium (NN), c is the status quo (NN) a is medium (NN), if b is small (NB), c is lowered (NB) a is small (NB), b is If large (PB), increase c (PB) a is small (NB), if b is medium (NN), increase c (PB) a is small (NB), b is small (NB) Then, c is the status quo (NN) If the above fuzzy rules are replaced by a fuzzy rule table, the matrix becomes as shown in the matrix table of FIG. 3, and the result of the rotating grate furnace rotation speed is as shown in FIG.

The rule unit 22 performs a fuzzy calculation by performing fine calculations on all of the nine fuzzy rules described above for each deviation between the measured value of the position of the center of gravity 16c of the flame 16 and the reference value. A process is performed to show the membership function value of the index a and the membership function value of the longitudinal burning index b in the membership function of the rotating grate furnace rotation speed c by the max-min method, respectively. The synthesis unit 23 obtains the inference result of the membership function of the rotating grate furnace rotation speed c indicated by the rule unit 22 as the actual rotation speed adjustment amount by the centroid method.

Next, the control of the rotational speed of the rotary grate furnace by the fuzzy rules performed by the fuzzy calculation unit 21 will be described.

FIG. 4 shows where the center of gravity 16c of the flame 16 has moved from the reference position X when the grate furnace main body 1 is viewed in a plan view, and the circumferential burning index a and the longitudinal burning index are measured. In the case where the direction index b is used, for example, the flame 1
6 is located at the X position (a = 0.0 m, b = 2.0
m) to the position of γ (a = 0.15 m, b = 2.25 m)
Shows the case of moving to.

The fuzzy control range of the burning index a and b and the rotation speed (rpm) c of the rotary grate furnace is -1.0 ≦ a
≦ 1.0, 0.75 ≦ b ≦ 3.25, 0.025 ≦ c ≦
0.045, and fuzzy control is applied within these ranges. If these ranges are not met, a warning will be issued and the operator will make manual adjustments.

Now, as shown in FIG. 4, when the position of the center of gravity 16c moves from the X position to the position of γ, it corresponds to the above-mentioned fuzzy rule, so that the rotational speed of the rotary grate furnace is reduced. In this case, the following operation is performed.

First, the membership function of the burning index a is as shown in FIG. 5A, the membership function of the burning index b is as shown in FIG. The membership function of the furnace rotation speed c is as shown in FIG.

In each of the membership functions shown in FIGS. 5A and 5B, the large, medium and small ranges are determined based on the intersections A and B, and the burning index a shown in FIG. Then, a> 0.1 is large, -0.1 ≦ a ≦ 0.1, medium, a <
It is judged to be small at −0.1, and according to the burning index b of FIG. 5B, large at b> 2.25 and medium at 1.75 ≦ b ≦ 2.25.
If b <1.75, it is determined to be small.

In FIG. 4, when the position of the center of gravity 16c of the flame 16 moves from X to the position of γ, the position of γ becomes a
Since a = 0.15 and b = 2.25, a is shown in FIG.
Since 0.15 exceeds the numerical value of 0.1, it is assumed to be large (PB), and b is 2.25 in FIG. 5 (b) and 1.75 ≦ b ≦ 2.2.
Since it is in the range of 5, it is set to medium (NN), and this is finely calculated by the membership function for nine items from the fuzzy rule based on the rule of FIG.

FIG. 6 shows the values of the membership function calculated for the fuzzy rules described above.
6A shows the value of the membership function based on the fuzzy rule at the position of γ, and FIG. 6B shows the value of the membership function based on the fuzzy rule. Similarly, FIGS. E) (he) (g)
(H) and (I) show the values of the membership function according to the fuzzy rules, respectively.

Since the fuzzy rule is that a is large and b is large, the value of the membership function of a is 0.7 at a = 0.15, and the value of the membership function of b is b Is 0.5 at 2.25, but 0.5 is obtained by applying the min method. If this is shown as a membership function of the number of rotations c of the rotary grate furnace, the value becomes as shown in the figure.

Similarly, in the fuzzy rule, since a is large and b is medium, the value of the membership function of a is 0.7, the value of the membership function of b is 0.5,
A smaller value of 0.5 is taken for the min method, and this is shown in the membership function of the rotational speed c of the rotary grate furnace.

Thus, the measured flame center-of-gravity point position γ
For all of the fuzzy rules ~, the value of the membership function of a and the value of the membership function of b are applied to the min method, and the smaller value is shown in the membership function of the rotational speed c of the rotating grate furnace. To go
From the results shown in the membership functions of the rotational speed c of the rotary grate furnace in FIGS. 6A to 6H, the inference result is represented as a graphic as shown in FIG.
The position of the center of gravity of the figure is obtained by the center of gravity method, and the value at that point is taken out as the rotational speed adjustment amount.

In FIG. 7, as for the rotational speed c of the rotary grate furnace, only the value of 0.035 is regarded as “just a good value (optimum value)”, and a value larger than that (c> 0.03) is set.
5) is set as large (PB), and a smaller value (c <0.035) is set as small (NB).

FIG. 7 shows the membership of the rotational speed c of the rotary grate furnace by applying the min method to all of the fuzzy rules when the flame center of gravity moves from X to γ as shown in FIG. The figure of the inference result shown in the function is shown, in which the position of γ falls within the range shown in the fuzzy rule ~, and based on the fuzzy rule, the rotational speed c of the rotary grate furnace is In FIG. 4 showing the result of the rotation speed c, NB is selected and the rotation speed is "decreased", and the center of gravity of the figure in FIG. Is obtained as the number of rotations (adjustment amount) to be corrected.

When the position of the flame center of gravity 16c is shifted from X to a position different from γ shown in FIG. 4, for that position, similar to the above, each membership of the burning index a and b for the fuzzy rule to all. Calculated by the function
By applying the in method to the membership function of the rotational speed c of the rotating grate furnace and obtaining the center of gravity of the inference result by the centroid method, the result corresponding to FIG. 7 is obtained, and the moved position is applicable. The adjustment value of the rotation speed c of the rotary grate furnace is obtained based on the fuzzy rules.

The value obtained by the fuzzy operation unit 21 is output as a rotational speed adjustment amount of the rotary grate furnace.
At the addition point 25, the rotational speed setting value 24 of the rotary grate furnace is added and input to the rotary grate furnace rotation controller 26 as control information, from which a control command is sent to the motor 8 of the control object 27, and The number of rotations of the lattice furnace body is controlled, the combustion state of the refuse 11 is changed, and the center of gravity 16c of the flame 16 is adjusted so as to settle within a reference range. In the above embodiment, the case where the number of fuzzy rules is set to 9 is shown, but the number of fuzzy rules may be arbitrarily determined.

[0035]

As described above, according to the method and apparatus for controlling combustion of a rotary grate furnace of the present invention, the position of the center of gravity of the flame caused by the combustion of dust in the rotary grate furnace is measured in the circumferential direction and the longitudinal direction. In order to determine the difference from the set value of the center of gravity point position and to set the measured center of gravity point position within a certain range,
For each fuzzy rule stored in advance in the rule unit of the fuzzy calculation unit, calculation is performed with each membership function of the circumferential burning index and the longitudinal burning index for the flame center of gravity position, and the min method is applied. The membership function of the rotating grate furnace speed for each rule is shown in the table, and the membership function of the rotating grate furnace speed c is synthesized by the fuzzy synthesis unit, and the center of gravity is obtained by the centroid method to adjust the speed. Since the amount is obtained and the combustion is controlled by adjusting the rotation speed of the rotary grate furnace based on the rotation speed adjustment amount, the following excellent effects can be obtained. (i) Since the measurement of the flame is performed not only in the longitudinal direction of the rotary grate furnace but also in the circumferential direction, and the position of the center of gravity where the luminance of the flame is the highest is measured, the dust layer and the calorie fluctuation are reduced. Thus, the position of the flame center of gravity of refuse combustion can be accurately grasped. (ii) The accuracy of the determination of whether or not to burn the refuse is improved due to the above (i). (iii) By simultaneously synthesizing the membership functions of the circumferential burning index and the longitudinal burning index by fuzzy control, it is possible to improve the accuracy of the control correction amount and perform long-term automatic control of combustion.

[Brief description of the drawings]

FIG. 1 shows an embodiment of a method and an apparatus for controlling combustion of a rotary grate furnace according to the present invention, wherein (a) is a block diagram,
(B) is a schematic view of the inside of the grate furnace main body as viewed in plan.

FIG. 2 is a block diagram showing a configuration of a fuzzy control arithmetic device in FIG.

FIG. 3 is a matrix table showing results of a rotating grate furnace rotation speed according to nine fuzzy rules stored in advance in a rule unit of a fuzzy operation unit in FIG. 2;

FIG. 4 is a schematic diagram showing each value of a circumferential burning index and a longitudinal burning index when the inside of a grate furnace main body is viewed in a plane, and a case where a flame center of gravity moves from an X position to a γ position. It is.

FIG. 5 shows membership functions of a circumferential burning index, a longitudinal burning index, and a rotating grate furnace speed.
(A) is a diagram showing large, medium, and small judgment criteria for the circumferential burning index, and (B) is a large and large burning index for the longitudinal burning index.
FIG. 3C is a diagram showing medium and small judgment criteria, and FIG. 3C is a diagram showing large, medium and small judgment criteria with respect to the rotating grate furnace rotation speed.

6 shows an example of a fuzzy calculation of the circumferential burning index a and the longitudinal burning index b based on the fuzzy regulation for the γ position in FIG. 4 and combining them to form a membership function of the rotating grate furnace speed. It shows the state shown, (b)
(I) is a diagram corresponding to the fuzzy rule.

7 is a diagram in which a rotational speed adjustment amount is obtained by a centroid method from an inference result obtained by synthesizing the rotary grate furnace rotational speed c shown in FIG.

FIG. 8 is a schematic diagram showing an example of a rotary grate furnace.

FIG. 9 is a view showing the measurement of a burn-off point at a flame generation point in a conventional grate furnace body.

FIG. 10 is a view showing a flame generating portion when a change of a dust layer occurs in a conventional grate furnace body.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Grate furnace main body 8 Motor 11 Garbage 16 Flame 16c Center of gravity 17 ITV camera 18 Image processing device 19 Fuzzy control arithmetic unit 20 Addition point 21 Fuzzy arithmetic unit 22 Rule part 23 Fuzzy synthesis unit 25 Addition point 26 Rotating grate furnace Rotation controller 27 Control target (rotary grate furnace) a Circumferential burning index b Longitudinal burning index c Rotating grate furnace rotation speed

Claims (3)

[Claims] 1. The inside of a grate furnace body in a rotary grate furnace in which air is introduced into the grate furnace body from below to incinerate refuse supplied inside while rotating the grate furnace body. The position of the center of gravity of the flame at the place where the refuse is burned is determined from the coordinates in the longitudinal direction and the circumferential direction of the grate furnace main body. The value of each membership function of the circumferential burning index and the longitudinal burning index is shown in the membership function of the rotating grate furnace speed for all the fuzzy rules and inferred. The center of gravity of the inference result obtained by synthesizing the membership function is obtained by the center of gravity method, and the value of the center of gravity is used as a rotation speed adjustment amount to adjust the rotation speed of the rotary grate furnace and perform combustion control. Grate Furnace combustion control method. 2. Fuzzy rules are made up of 9 items in combination of large, medium, and small circumferential burning index and large, medium, and small longitudinal burning index, and the rotating grate furnace speed is calculated for each item. The method for controlling combustion in a rotary grate furnace according to claim 1, wherein the inference is performed. 3. An image signal of the combustion state of the refuse in the grate furnace main body captured by a camera for imaging the inside of the grate furnace main body of the rotary grate furnace is processed to determine the position of the center of gravity of the fire in the grate furnace main body. An image processing device is provided that measures a circumferential burning index and a longitudinal burning index obtained from coordinates from the circumferential direction and the longitudinal direction, and each of the circumferential and longitudinal burning measured by the image processing device. From the values of the membership function of the circumferential burning index and the membership function of the longitudinal burning index for all fuzzy rules for each deviation between the direction index and these reference values, the membership function for the rotating grate furnace speed And a fuzzy synthesizing unit for obtaining the center of gravity of the inference result of the membership function of the rotating grate furnace rotation speed indicated by the rule unit as a rotation speed adjustment amount. A fuzzy calculation unit, and a rotation grate furnace rotation amount adjustment amount obtained by the fuzzy calculation unit and a rotation grate furnace rotation speed set value. A combustion control device for a rotary grate furnace, characterized by having a configuration provided with a fuzzy control arithmetic device having a combination point.