JP2003083524A - Combustion state monitor device and combustion controller for boiler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a combustion state monitor device for a boiler capable of highly accurately monitoring the combustion state of a solid fuel and a combustion controller for a boiler capable of properly deciding the combustion state of the solid fuel and performing an optimum combustion control. SOLUTION: The combustion state monitor device for a boiler for monitoring the combustion state of the solid fuel in a black liquid recovery boiler comprises an image pick-up means which has sensitivity characteristics of the sensitivity of an infrared ray area higher than those of the sensitivity of a visible ray area and picks up the solid fuel in a sherbet state in the black liquid recovery boiler and a switching means for switching a state that infrared rays are incident on the image pick-up means and a state that visible rays are incident on the image pick-up means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion state monitoring device and a combustion control device for a boiler used for a solid fuel boiler, a black liquor recovery boiler used as a power generation power plant in a paper mill, and the like.

[0002]

2. Description of the Related Art An example of a conventional combustion state monitoring device for a black liquor recovery boiler will be described. (Conventional Example 1) FIG. 6 is a diagram showing a configuration example of a conventional combustion state monitoring device for a boiler. In FIG. 6, the black liquor recovery boiler 10 burns solid fuel in the furnace. Black liquor (waste liquor after pulp cooking) is added to the boiler as fuel. The solid content (referred to as char) of the constituents of this black liquor is burned while accumulating on the bottom of the boiler furnace. This accumulated formation is called charbed. The char bed 11 decreases due to combustion. By observing the shape of the char bed 11, the combustion state of the solid fuel can be monitored. General-purpose ITV camera 12
a to 12d photograph the shape of the char bed 11. In the illustrated example, the general-purpose ITV cameras 12a to 12d photograph the char bed 11 from four directions. Black liquor recovery boiler 1
No. 0 furnace wall is provided with windows 13a to 13d for monitoring and measurement. The windows 13a to 13d are made of, for example, heat resistant glass or the like. The imaging units 12a to 12d capture images of the char bed 11 in the furnace through the windows 13a to 13d.

In the in-reactor monitoring using the general-purpose ITV camera in the conventional example shown in FIG. 6, the combustion of solid fuel is a mixture of the combustion of volatile components and the combustion of solid components, and an image of a flame in which volatile components are burned has pixels. White halation occurs. Therefore, the image of the solid content is affected by halation, and clear and stable image information cannot be obtained. As described above, in the black liquor recovery boiler, the shape of the char bed is blurred by the flame of the volatile fuel component or becomes an image indistinguishable from the background furnace wall. Therefore, there is a problem in that the shape of the charbed that is originally desired to be monitored cannot be sufficiently monitored.

FIG. 7 is a diagram showing an example of a photographed image by the apparatus of FIG. As shown in Fig. 7, in the image taken with a general-purpose ITV camera, the effect of halation due to the burning flame of volatile components is strong, and the effect of the furnace wall in the background is also strong, so the char bed molding condition is sufficient. I can't monitor.

(Prior art example 2) A light emitting element and a light receiving element of a laser beam are arranged to face each other on the furnace walls facing each other of a black liquor recovery boiler. Plural pairs of the light emitting element and the light receiving element are arranged on the furnace wall. It is determined that there is a charbet at a position where the light receiving element can receive the laser beam emitted from the light emitting element, and no charbet exists at a position where the laser beam cannot be received. In this way, the shape of the char bed is pseudo-estimated by detecting the position where the char bed exists and the position where the char bed does not exist.

FIG. 8 is a diagram showing an example of an image showing the charbed shape obtained by the estimation. In FIG. 8, the light receiving element is arranged at a position where there is a circle. Black circles are light receiving elements that receive a laser beam, and white circles are light receiving elements that do not receive a laser beam. It is estimated that there is a charbed contour between the black circle and the white circle, and the contour line 14 is drawn. The charbed shape is estimated from the contour line 14.

However, in the monitoring of the charbed shape using a laser beam, it can be determined whether or not there is a charbed in the section divided by the light receiving element, but the amount of information is scarce and sufficient monitoring is performed in comparison with the image information. Can not do it. If the number of light emitting elements and light receiving elements is increased to increase the amount of information, the device becomes expensive.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and by using an imaging means having high sensitivity in the infrared region, the combustion state of solid fuel can be accurately measured. It is an object of the present invention to provide a boiler combustion state monitoring device that can be monitored and a boiler combustion control device that can appropriately determine the combustion state of solid fuel and perform optimal combustion control.

[0009]

SUMMARY OF THE INVENTION The present invention is a boiler combustion state monitoring device and combustion control device configured as follows.

(1) In a boiler combustion state monitoring device for monitoring the state of solid fuel combustion in a black liquor recovery boiler, the sensitivity in the infrared region has a higher sensitivity characteristic than the sensitivity in the visible light region, A boiler characterized by having an image pickup means for picking up a solid fuel in a charbed state in the recovery boiler, and a switching means for switching between a state in which infrared rays are incident on the image pickup means and a state in which visible light is incident. Combustion condition monitoring device.

(2) The switching means detachably mounts the infrared cut filter between the infrared cut filter that allows visible light to pass therethrough and blocks infrared light, and the image pickup means and the solid fuel in the form of a char bed. (1) The combustion state monitoring device for a boiler according to (1), further comprising:

(3) The combustion state monitoring device for a boiler according to (1), characterized in that the imaging means outputs contour image information of solid fuel in which halation has not occurred.

(4) The boiler combustion state monitoring device according to (1), characterized in that a plurality of the imaging means are provided to image the solid fuel in the form of char bed from different directions.

(5) The boiler combustion state monitoring device according to any one of (1) to (4) is provided, and the stable state of combustion is determined based on the contour image of the solid fuel obtained from the imaging means. A combustion control device for a boiler, further comprising combustion control means for controlling the injection of fuel into the black liquor recovery boiler based on the determination result.

[0015]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing an embodiment of a boiler combustion state monitoring apparatus according to the present invention. In FIG. 1, the same parts as those in the previous figure are designated by the same reference numerals. In FIG. 1, the camera 2
0a to 20d photograph the shape of the char bed 11.
In the illustrated example, the cameras 20a to 20d are the charbed 11
Is being photographed from all sides. The cameras 20a to 20d have sensitivity characteristics in which the sensitivity in the infrared region is higher than the sensitivity in the visible light region.

FIG. 2 is a block diagram showing the construction of an embodiment of a boiler combustion state monitoring apparatus according to the present invention. Figure 2
The photographing optical system 21 is a lens through which the light from the monitored object 30 is transmitted. The monitored object 30 is a solid fuel that burns in the furnace of the black liquor recovery boiler. The switching unit 22 switches between a state in which infrared rays are incident on the imaging unit 23 and a state in which visible light is incident. The switching unit 22 includes an infrared cut filter 221 and a mounting unit 222. The infrared cut filter 221 is a filter that passes visible light and blocks infrared light. The mounting means 222 is the imaging means 23.
Between the infrared ray cut filter 221 and the monitored object 30
Put on and take off freely.

The mounting means 222 inserts an infrared cut filter 221 between the image pickup means 23 and the monitored object 30 when the visible light is made incident on the image pickup means 23, and makes visible light and infrared rays enter the image pickup means 23. In some cases, the infrared cut filter 221 is removed from between the image pickup means 23 and the monitored object 30. The mounting means 222 includes a motor or the like that moves the infrared cut filter 221 back and forth in the direction of the arrow in the drawing.

The image pickup means 23 takes an image of the combustion state of the solid fuel. The image pickup unit 23 is, for example, a CCD camera including a CCD image pickup device (charge coupled device), and outputs the picked-up image to the signal processing circuit 24 as image information (image signal). The image pickup means 23 has sensitivity characteristics in which the sensitivity in the infrared region is higher than the sensitivity in the visible light region.

The signal processing circuit 24 adjusts the brightness of the image based on the image information output by the image pickup means 23 (γ correction).
It is a circuit to do. The signal processing circuit 24 outputs the adjusted image information to the display device 40. The display device 40 displays the combustion state of the solid fuel on the screen based on the image information output by the signal processing circuit 24. Although FIG. 2 shows the configuration in which one camera is connected to the display device,
Not limited to this, a plurality of cameras may be connected to the display device as shown in FIG.

FIG. 3 is a diagram showing the sensitivity characteristics of the image pickup means and the infrared cut filter in the boiler combustion state monitoring apparatus according to the embodiment of the present invention. The vertical axis of FIG. 3 is the sensitivity (gain), and the horizontal axis is the wavelength. Graph 50 indicated by a two-dot chain line
Is a graph showing the sensitivity of the image sensor, and a graph 51 shown by a solid line.
Is a graph showing the sensitivity of the infrared cut filter.

As shown in FIG. 3, the infrared cut filter 2
Reference numeral 21 has a band characteristic for blocking infrared rays, and the image pickup means 23 has a sensitivity characteristic such that the sensitivity in the infrared region is higher than the sensitivity in the visible light region. When the combustion state is imaged with the infrared cut filter 221 attached, halation occurs in the imaged image, but when the combustion state is imaged with the infrared cut filter 221 removed, the imaged image does not have halation.

When the infrared cut filter 221 is mounted, the image pickup means 23 receives visible light with the dynamic range set to the sensitivity range S1. Therefore, when the image pickup unit 23 adjusts the aperture and the shutter speed so that the combustion flame of the volatile fuel component can be seen, halation occurs in a bright portion.

On the other hand, when the infrared cut filter 221 is removed, the image pickup means 23 receives visible rays and infrared rays. As shown in FIG. 3, the image pickup unit 23 has sensitivity characteristics such that the sensitivity to infrared rays is higher than the sensitivity to visible light. As a result, when the image pickup unit 23 adjusts the aperture and the shutter speed so that the solid content that generates a large amount of infrared rays can be seen, the imageable range shifts from the sensitivity range S1 to the sensitivity range S2, and thus the infrared range. It becomes high sensitivity to, and becomes low sensitivity to visible light. For this reason, the image pickup unit 23 mainly takes an image of a portion such as a solid matter that emits a large amount of infrared rays, and hardly captures a flame of a volatile fuel component that emits a small amount of infrared rays. As a result, an image without halation is output as image information.

FIG. 4 is a diagram showing an example of an image picked up by the image pickup means 23. This image is infrared cut filter 22
1 is an image taken in a state where it is detached. Imaging means 2
Since 3 has a higher sensitivity in the infrared region than in the visible light region, the contour shape of the charbed without halation can be monitored on the screen.

FIG. 5 is a block diagram showing the construction of an embodiment of a combustion control device for a boiler according to the present invention. In FIG. 5, the combustion control means 60 includes a signal processing circuit 24 from the image pickup means 23.
The stable state of combustion is determined based on the contour image of the char bed obtained through the, and the black liquor recovery boiler 1 is determined based on the determination result.
Controls injection of fuel into zero.

In the embodiment, the case where four cameras are installed has been described, but the number of cameras other than this may be installed.

[0027]

According to the present invention, the following effects can be obtained.

In the inventions according to claims 1 to 3, a state in which visible light and infrared rays are incident and a state in which visible light is incident on the image pickup means whose sensitivity in the infrared region is higher than that in the visible light region. The switching means switches to and. Using this image pickup means, an image of solid fuel in the form of a char bed is picked up in the black liquor recovery boiler. Therefore, a portion having a high infrared emission amount such as a solid content is imaged, the flame of the volatile fuel component having a low infrared emission amount becomes invisible, and a clear image without halation can be obtained. Thereby, the combustion state of the solid fuel in the black liquor recovery boiler can be monitored with high accuracy.

According to the fourth aspect of the present invention, a plurality of image pickup means are provided and the charbed solid fuel is imaged from different directions. Therefore, the combustion state of the solid fuel can be monitored in multiple directions.

According to the fifth aspect of the invention, the combustion control means determines the stable state of combustion based on the contour image of the solid fuel without halation obtained from the imaging means, and based on the determination result, the fuel to the boiler is determined. Control the input of. Therefore, it is possible to appropriately determine the combustion state of the solid fuel and perform optimal combustion control.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of a combustion state monitoring device for a boiler according to the present invention.

FIG. 2 is a configuration block diagram showing an embodiment of a combustion state monitoring device for a boiler according to the present invention.

FIG. 3 is a diagram showing sensitivity characteristics of an imaging unit and an infrared cut filter in the boiler combustion state monitoring apparatus according to the embodiment of the present invention.

FIG. 4 is a diagram showing an example of an image picked up by an image pickup means.

FIG. 5 is a configuration block diagram showing an embodiment of a combustion control device for a boiler according to the present invention.

FIG. 6 is a diagram showing a configuration example of a conventional boiler combustion state monitoring device.

7 is a diagram showing an example of a captured image by the apparatus of FIG.

FIG. 8 is a diagram showing an example of an image showing a charbed shape obtained by estimation.

[Explanation of symbols]

10 Black liquor recovery boiler 11 char bed 20, 20a-20d camera 22 Switching means 23 Imaging means 60 Combustion control means 221 infrared cut filter 222 mounting means

Claims (5)

[Claims] Claim: What is claimed is: 1. A combustion state monitoring device for a boiler, which monitors a state of burning solid fuel in a black liquor recovery boiler, wherein the sensitivity in the infrared region is higher than that in the visible light region, and the black liquor recovery is performed. A boiler characterized by having an image pickup means for picking up an image of solid fuel in a charbed state in the boiler, and a switching means for switching between a state where infrared rays are incident on the image pickup means and a state where visible light is incident. Combustion condition monitoring device. 2. The switching means detachably mounts the infrared cut filter between the infrared cut filter that allows visible light to pass therethrough and blocks infrared light, and the image pickup means and a solid fuel in a charbed shape. The combustion state monitoring device for a boiler according to claim 1, further comprising mounting means. 3. The boiler combustion state monitoring device according to claim 1, wherein the imaging unit outputs contour image information of solid fuel in which halation has not occurred. 4. The combustion state monitoring device for a boiler according to claim 1, wherein a plurality of the image pickup means are provided to image the charbed solid fuel from different directions. 5. The boiler combustion state monitoring device according to any one of claims 1 to 4 is provided, and a stable combustion state is determined based on a solid fuel contour image obtained from the imaging means. A combustion control device for a boiler, comprising combustion control means for controlling injection of fuel into the black liquor recovery boiler based on a determination result.