JPH0755125A - Method and device for burning control of waste incinerator - Google Patents

Abstract

PURPOSE:To provide a method which enables a proper burning control of a waste incinerator by detecting remains of unburnt waste correctly and detecting a burning position stably in the time aspect. CONSTITUTION:A television camera 23 takes pictures of the inside of a waste incinerator 13 for a prescribed time to obtain a plurality of inside images of the incinerator 13. Among picture elements corresponding to the plurality of inside images, one whose brightness is the lowest of all is selected as a minimum value image, which adopts the lowest brightness as its picture element. Similarly, one whose brightness is the highest of all is selected as a maximum value image, which adopts the highest brightness as its picture element. Then a burning position and a burnt point in a furnace are detected from these minimum and maximum value images, and a burning control of the waste incinerator is carried out based on these values.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for controlling combustion in a refuse incinerator, and more particularly to a combustion condition in the incinerator by processing image information obtained by imaging the inside of the refuse incinerator with a television camera. The present invention relates to a method and an apparatus for monitoring combustion and controlling combustion in an incinerator.

[0002]

2. Description of the Related Art In a refuse incinerator, in order to burn the refuse in the incinerator so that the unburned residue is not left, detection and control of the point where the refuse is burned out (hereinafter referred to as the burn-off point) are required. It becomes important.

Further, when the quality of the refuse supplied to the refuse incinerator changes, the position of the most burned portion (hereinafter referred to as the combustion position) also changes. Therefore, it is necessary to detect the combustion position and control it so that it is at an appropriate position near the center of the furnace in order to keep the combustion stable even if the waste quality changes.

Conventionally, in order to solve such a problem, the burn-out point is obtained from the image information obtained by imaging the inside of the refuse incinerator with a television camera so as to eliminate the unburned residue of the refuse in the refuse incinerator. Control method (Japanese Patent Laid-Open No. 64-67)
523, JP-A-1-111124, JP-A 1-21
No. 403) is known. Further, a method for obtaining a burn-out point from a red signal of a color image obtained by imaging the inside of a refuse incinerator and controlling the burning position to be constant (Japanese Patent Laid-Open No. 3-6)
No. 6566) is known.

[0005]

In the above conventional method, since the burn-out point is obtained from the brightness information of the image in the refuse incinerator, the unburned portion of the dust and the most burned portion, that is, It was not possible to distinguish from the combustion position, and it was difficult to perform combustion control accurately. That is, in the conventional combustion control method, since a single piece of control information, which is a burnout point, is detected and controlled from the image information in the refuse incinerator, stable and complete combustion is always maintained against fluctuations in the waste quality. It was difficult to do.

Therefore, the present invention improves these conventional drawbacks, and by detecting the combustion position and the burn-out point separately, a time-stable combustion position is secured against fluctuations in dust quality. At the same time, it is an object of the present invention to provide a method and an apparatus capable of performing accurate combustion control of a refuse incinerator so as not to generate unburned residue of the refuse.

[0007]

According to the present invention, the inside of the refuse incinerator is imaged by a television camera for a predetermined time to obtain a plurality of in-furnace images, and the plurality of in-furnace images correspond to each other. Select the pixel with the lowest brightness from each pixel to obtain the minimum value image with that brightness value as the pixel, and similarly select the pixel with the highest brightness from each corresponding pixel and select the maximum value with that brightness value as the pixel. An image is obtained, and the combustion position and burn-out point in the furnace are respectively detected from these minimum value image and maximum value image, and the combustion of the incinerator is controlled according to the magnitude of the value. A combustion control method for a rubbish incinerator is obtained.

Further, according to the present invention, the combustion position in the furnace is detected by the position in the image of the pixel of which the luminance is equal to or more than a predetermined value among the pixels forming the minimum value image. A combustion control method for a refuse incinerator characterized by the above is obtained.

Further, according to the present invention, the burn-out point in the furnace is detected by the position in the image of the pixel of which the brightness is less than or equal to a predetermined value among the pixels forming the maximum value image. A combustion control method for a refuse incinerator characterized by the above is obtained.

Further, according to the present invention, a television camera for imaging the inside of the refuse incinerator for a predetermined time and a plurality of in-furnace images obtained by the television camera at different times are collected as brightness information of each pixel. The image memory to be stored as, and the multiple in-furnace images stored in this image memory are read out, and the pixel with the lowest brightness and the pixel with the highest brightness are selected from the corresponding pixels of these images. Image processing means for forming a minimum value image and a maximum value image each having the brightness value as a pixel, and a combustion position and a burn-off point in the furnace from the minimum value image and the maximum value image obtained by the image processing means, respectively. Means for calculating
There is provided a combustion control device for a refuse incinerator, comprising: a means for controlling the combustion of the incinerator according to the combustion position and the size of the burn-off point calculated by the calculating means.

According to the present invention, the means for calculating the combustion position and the burn-out point in the furnace have the luminance of the pixels constituting the minimum value image and the maximum value image which are equal to or higher than a predetermined value. A combustion control device for a refuse incinerator, characterized in that it is constituted by means for obtaining the position in the image of a pixel when the pixel reaches a predetermined number when counted from a predetermined position in the image.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing the structure of a refuse incinerator to which the present invention is applied. The refuse 11 to be incinerated is pushed into the incinerator 13 by the feeder 12. The first to third stokers 14, 15 and 16 arranged on the entire floor of the incinerator 13 move the inside of the furnace and burn it while appropriately stirring the refuse 11 that has entered the furnace. The first stoker 14 is disposed on the furnace inlet side, the second stoker 15 is disposed on the furnace center, and the third stoker 16 is disposed on the furnace outlet side, and the transport speed of dust can be changed independently.

Combustion air is blown into the furnace from the lower side of the furnace by the forced air blower 17. The total amount of combustion air supplied into the furnace is adjusted by the combustion air main damper 18. Further, the first to fourth sub-dampers 19, 20, 21, 22 adjust the ratio of the amount of combustion air entering each part in the furnace to promote and control the combustion of dust on each damper. The number of sub-dampers may be three depending on the incinerator. The state of combustion in the incinerator 13 is imaged by the TV camera 23 installed on the furnace outlet side.

FIG. 2 is a block diagram showing the construction of the combustion control system of the incinerator using the image inside the incinerator taken by the television camera 23. The analog image information captured by the television camera 23 is converted into digital image information by the image input device 34 at regular intervals, and the image memory 3
Stored in 5. The computer 36 obtains the burn-out point Bp and the combustion position Bo from the digital image information stored in the image memory 35 by the procedure described below. Furthermore, Calculator 3
6 calculates the amount of dust supplied and the amount of combustion air to each part in the furnace based on the burn-out point Bp and the combustion position Bo, and gives a command value to the dust supply amount control device 37 and the combustion air control device 38, respectively.

The refuse supply amount control device 37, based on the command value obtained by the computer 36, the feeder 12 of the incinerator, the first
Through the operation of the third stokers 14, 15 and 16, the amount of dust supplied into the furnace and the moving speed of the dust in each part of the furnace are adjusted.

The amount of dust supplied to the furnace can be adjusted by increasing or decreasing the number of times the feeder 12 is repeated. The moving speed of the dust near the furnace entrance can be adjusted by the speed of the first stoker 14 and the number of times of turning on / off. Further, the moving speed of dust near the center of the furnace can be adjusted by the speed of the second stoker 15 and the number of times of turning on / off. further,
The moving speed of the dust near the furnace outlet can be adjusted by the speed of the third stoker 16 and the number of times of turning on / off.

The combustion air control device 38, based on the command value obtained by the computer 36, the combustion air main damper 1 of the incinerator.
8. The first to fourth sub-dampers 19, 20, 21, and 22 are operated to adjust the total amount of combustion air and the ratio of the air supplied to each part in the furnace. That is, the total amount of combustion air can be adjusted by opening and closing the combustion air main damper 18.
Further, the ratio of the combustion air supplied to each part in the furnace can be adjusted by changing the opening degrees of the first to fourth sub dampers 19, 20, 21, 22.

Next, a method of calculating the combustion position Bo and the burnout point Bp will be described. FIG. 3 is a diagram showing an example of an image in the combustion furnace taken by the television camera 23. The image inside the combustion furnace is
Depending on the height of each stoker, the installation position of the TV camera 23, the angle, etc., the upper part 41 of the screen is near the furnace entrance and the central part 4
The combustion state near the center of the furnace is shown in 2 and the combustion state near the exit of the furnace is shown in the lower part 43. The central part 44 of the strong flame in the furnace is a number 1
Since the place does not move in the furnace for a fixed time of about 0 seconds to several minutes, the images are taken at the same position on the image. On the other hand, the outer portion 45 of the flame tends to change its shape with time. Further, the flame 46 of the unburned residue of the dust easily changes in luminance with time.

In the present invention, a plurality of images captured at different times are obtained by capturing an image of the inside of the incinerator 13 with the television camera 23 for a predetermined time, and the images are processed as follows. By doing so, the combustion position and burn-out point are detected.

FIG. 4 is a diagram showing the relationship between the pixel coordinates of the in-furnace image captured by the television camera 23 at time T and the brightness information thereof. In the figure, the number of pixels in the horizontal direction of the image is Nx, and the number of pixels in the vertical direction is Ny. Also,
The luminance L at time T of the x-th pixel from the left to the right and the y-th pixel from the top to the bottom is expressed as L (x, y, T).

However, 0≤x≤Nx-1, 0≤y≤Ny
-1. In addition, the value of each pixel takes a larger value as the brightness increases.

The image memory 35 shown in FIG.
K in-furnace images taken at 1, T2 ... Tk are N
It is stored as luminance information L (x, y, T) of x × Ny pixels. Using the brightness information L (x, y, T) of the in-furnace images at these different times, the minimum brightness is obtained from the pixels at the corresponding coordinates (x, y) of each of the k images, and the minimum brightness is calculated. Let the luminance be the pixel at the coordinates (x, y). This operation is performed for all Nx × Ny pixels,
One image is composed by a group of these minimum luminance pixels. Hereinafter, the image thus synthesized will be referred to as a minimum value image. Similarly, one image obtained by obtaining the maximum brightness from the pixels of the corresponding coordinates (x, y) of each of the k images and combining them is called a maximum value image.

Letting Lmin (x, y) and Lmax (x, y) be the pixel values at the coordinates (x, y) of the minimum value image and the maximum value image thus obtained, respectively, It is expressed as in Equations 1 and 2.

[0024]

[Formula 1]

[0025]

[Formula 2] A portion of the minimum value image in which the pixel value is larger than the constant value Th1 is a flame portion that does not change with time. That is,
It is considered to be a stable burning portion like the central portion 44 of the flame in FIG. Therefore, if a value obtained by binarizing the pixel value at the coordinates (x, y) of the minimum value image with the constant value Th1 as a reference is M (x, y), M (x, y)
y) is expressed as the following Expression 3.

[0026]

[Formula 3] Next, 1 in the y row of the binarized value M (x, y)
The sum S (y) of the columns is calculated as in the following Expression 4.

[0027]

[Formula 4] Furthermore, Sall of the sum of M (x, y) in all images is calculated as in the following Expression 5.

[0028]

[Formula 5] Then, the maximum y that satisfies the expression in parentheses of the following equation 6
Is the combustion position Bp.

[0029]

[Formula 6] However, ε is a positive number from 0 to 1 and is, for example, 0.05.

The combustion position Bp obtained as described above is shown in FIG.
Is represented by the number of pixels counted from the upper end to the lower end of the image. The combustion position Bp is the position of the lower end of the central portion 44 of the flame in FIG.
As shown in (A), the position where the flame is burning out in the minimum value image is represented. Since the time variation of the flame is removed in the minimum value image, it represents the position of the point where combustion is stable in the furnace.

The burn-out point Bo is 2 for the maximum value image.
Th2 in place of the threshold value Th1 for quantizing, and Lmin
Instead of Lmax, Lmax is used to perform the same process as above.

The burn-out point Bo, as shown in FIG. 5 (B), represents the point where the flame of the maximum value image has started burning. The flame of the maximum value image also includes the flame of the unburned dust that changes with time. Therefore, the burn-out point Bo is the combustion position B
The value is larger than p (position from the furnace outlet, or position on the lower side of the screen). In the maximum value image, M (x,
Since the point of y) = 0 is considered to be a point where there is no flame, the dust is completely burned out in the portion below the burnout point Bo on the image.

The binarization thresholds Th1 and Th2 are set so that pixels having a high luminance representing a flame portion and pixels having a low luminance representing a portion other than flame can be separated from the minimum value image and the maximum value image, respectively. To make a decision. As an example, when the aperture of the television camera 23 is fixed and imaged, and the brightness of each pixel of the image is discretized with a numerical value in the range of 0 to 255, Th1 and Th2 are set to values of about 100 to 200. To do.

When refuse that is hard to burn, such as dust containing a large amount of water, enters the furnace, the combustion position Bp moves to the exit side of the furnace because the waste is not sufficiently dried near the entrance of the furnace.
Therefore, when the combustion position Bp becomes a large value, the operation is performed so that the moving speed of dust by the stoker 14 or the stoker 15 becomes small. Alternatively, the opening degree of the sub-damper 19 is increased to accelerate the drying of dust near the furnace entrance.

Further, when dry and flammable dust enters the furnace, it begins to burn near the entrance of the furnace, and the combustion position B
p moves to the entrance side of the furnace. Therefore, the combustion position B
When p becomes a small value, the stalker 14 or the stalker 15 is operated so as to increase the moving speed of dust. Alternatively, the opening degree of the sub-damper 19 is reduced to suppress the burning and drying of dust near the furnace entrance.

When the dust is not completely burned in the center of the furnace, the unburned dust appears near the furnace outlet and burns. In order to completely burn the refuse and improve the ash quality, it is necessary to completely burn the unburned residue. Normally, the flame when the unburned refuse burns has less momentum than the flame in the center of the furnace, the flame fluctuates, and the temporal change is large. In the minimum value image, since this flame is removed, the combustion position Bp is not affected and represents the position of the flame in the center of the furnace where the momentum is strong. On the other hand, in the maximum value image, this flame is displayed throughout the image as a bright portion on the image. Therefore, burnout point B
When there is an unburned residue, o is a value closer to the furnace outlet than the combustion position Bp (a numerically large value). Further, when there is no unburned residue, the value is approximately the same as the combustion position Bp.

Therefore, when Bo has a large value (there is an unburned residue near the furnace outlet), the remaining speed of the unburned residue is completely burned. Therefore, the average speed of the stoker 16 is reduced to reduce the moving speed of the dust near the furnace outlet. Slow down. Alternatively, the fourth sub-damper 22 is opened to increase combustion air near the furnace outlet and promote combustion of dust near the furnace outlet.

The computer 36 uses the above-described method to set the combustion position B.
p and the burn-out point Bo are obtained, and a command to the feeder 12 and the first to third stokers 14, 15 and 16 is output to the dust supply amount control device 17 according to the values. Further, the combustion air main damper 18, the first to fourth sub-dampers 19, 2
The commands 0, 21, and 22 are output to the combustion air control device 38.

[0039]

According to the present invention described above, the minimum value image and the maximum value image are obtained from a plurality of images taken inside the incinerator at different times, so that the center position of combustion and the burn-off point are accurately determined. Can be detected. Therefore, the control for burning the dust at the proper position in the center of the furnace and the control for improving the ash quality of the dust can be accurately performed.

That is, according to the present invention, the burn-out point and the combustion position, which have been conventionally used without distinction, are clearly distinguished, and they are separately detected by an image processing method that emphasizes the respective features. Is used for the combustion control, it is possible to eliminate the unburned residue of the waste in the waste incinerator and to more accurately control the fluctuation of the combustion position due to the quality of the waste.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing the structure of a refuse incinerator to which the present invention is applied.

FIG. 2 is a block diagram showing a configuration of a combustion control system of the refuse incinerator according to the present invention.

FIG. 3 is a diagram showing an example of an image in a refuse incinerator to which the present invention is applied.

FIG. 4 is a diagram showing the relationship between the coordinates of pixels of an in-furnace image and the brightness information thereof according to the present invention.

FIG. 5 is a diagram showing positions of a combustion position Bp and a burnout point Bo in the present invention.

[Explanation of symbols]

 11 refuse 12 feeder 13 refuse incinerator 14 first stoker 15 second stoker 16 third stoker 17 forced air blower 18 combustion air main damper 19 first auxiliary damper 20 second auxiliary damper 21 third auxiliary damper 22 Fourth sub-damper 23 TV camera 34 Image input device 35 Image memory 36 Computer 37 Waste supply amount control device 38 Combustion air control device

Claims (5)

[Claims] 1. The inside of the refuse incinerator is imaged by a television camera for a predetermined time to obtain a plurality of in-furnace images, and the pixel having the lowest brightness among the corresponding pixels of the plurality of in-furnace images. To obtain the minimum value image with the brightness value as a pixel, and similarly obtain the maximum value image with the brightness value as the pixel by selecting the pixel with the highest brightness among the corresponding pixels,
The waste incinerator characterized by detecting the combustion position and burn-out point in the furnace from these minimum value image and maximum value image, respectively, and controlling the combustion of the incinerator according to the magnitude of these values. Combustion control method. 2. The combustion control method according to claim 1, wherein
Combustion of a refuse incinerator, characterized in that among the pixels forming the minimum value image, the combustion position in the furnace is detected by the position in the image of the pixel whose luminance is a predetermined value or more. Control method. 3. The combustion control method according to claim 2,
Of each of the pixels forming the maximum value image, the burn-in point in the furnace is detected by the position in the image of the pixel whose brightness is less than or equal to a predetermined value. Combustion control method. 4. A television camera for imaging the inside of the refuse incinerator for a predetermined time, and an image for storing a plurality of in-furnace images obtained by this television camera at different times as a set of luminance information of each pixel. Read out the memory and multiple in-furnace images stored in this image memory, select the pixel with the lowest brightness and the pixel with the highest brightness from the corresponding pixels in these images, and select the brightness values respectively. Image processing means for forming a minimum value image and a maximum value image having pixels as pixels, and means for calculating the combustion position and burn-out point in the furnace from the minimum value image and the maximum value image obtained by the image processing means, respectively. And a means for controlling the combustion of the incinerator according to the combustion position and the size of the burn-off point calculated by the calculating means, and the combustion control of the refuse incinerator. Your device. 5. The combustion control device according to claim 4,
Means for calculating the combustion position and burnout point in the furnace,
The position of the pixel in the image when the number of pixels whose brightness is equal to or higher than a predetermined brightness reaches a predetermined number from the predetermined position of the image among the pixels forming the minimum value image and the maximum value image, respectively. Combustion control device for a refuse incinerator, characterized in that it is configured by means for obtaining.