Charbed detecting device and boiler

Abstract

To provide a charbed detecting device capable of suppressing costs.SOLUTION: A charbed detecting device that detects the charbed deposited in a furnace includes: an imaging device that picks up successive images that are successive in time-series of the charbed from the side-wall side of the furnace; and an identifying device that identifies the surface position of the charbed based on the successive images. The identifying device includes: a grid creating unit that creates a plurality of grids obtained by dividing the successive images along the vertical direction and the intersecting direction with the vertical direction; a variability calculating unit that calculates the variability of color information based on a change over time for each of the plurality of grids; and an allocating unit that allocates each of the plurality of grids to either a flame region where the variability is large or a charbed region where the variability is small.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a char bed detection device that detects char beds that accumulate in a furnace, and a boiler that includes this char bed detection device. [Background technology]

[0002] Char beds have been monitored for some time, and for example, Patent Documents 1 and 2 disclose that the shape of a char bed is obtained based on infrared light obtained by an infrared camera. Patent Documents 3 and 4 disclose that the shape of a char bed is obtained based on infrared light obtained by a radiation thermometer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5028267 [Patent Document 2] Japanese Patent Application Publication No. 15046 / 1983 [Patent Document 3] Japanese Patent Application Publication No. 5-172303 [Patent Document 4] Japanese Patent Application Publication No. 4-73286 Summary of the Invention [Problem to be solved by the invention]

[0004] However, infrared cameras and radiation thermometers capable of capturing infrared light are expensive, which significantly increases the cost of the char bed detection device.

[0005] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a char bed detection device that can reduce costs compared to the above-mentioned conventional char bed detection devices. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the char bed detection device of the present disclosure is a char bed detection device that detects char bed accumulated in a furnace, and includes: an imaging device that captures successive images of the char bed in chronological order from the side wall of the furnace; and an identification device that identifies the surface position of the char bed based on the successive images.The identification device includes: a grid creation unit that creates a plurality of grids by dividing the successive images along each of the vertical direction and a cross direction that crosses the vertical direction; a variation calculation unit that calculates the variation in color information based on temporal changes for each of the plurality of grids; and an allocation unit that assigns each of the plurality of grids to either the flame region with large variation or the char bed region with small variation. [Effects of the Invention]

[0007] The char bed detection device of the present disclosure can reduce costs compared to conventional char bed detection devices that are equipped with an infrared camera or radiation thermometer that can capture infrared rays. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating a schematic configuration of a boiler equipped with a char bed detection device according to an embodiment. [Figure 2] FIG. 2 is a schematic functional block diagram of a specific device according to an embodiment. [Figure 3] FIG. 1 is a diagram illustrating a grid according to an embodiment. [Figure 4] FIG. 1 is a diagram illustrating dispersion according to an embodiment. [Figure 5] FIG. 2 is a diagram illustrating a flame region and a char bed region according to an embodiment. [Figure 6] 10 is a graph showing the relationship between Wx(y) and the y coordinate of the grid. DETAILED DESCRIPTION OF THE INVENTION

[0009] The following describes a char bed detection device according to an embodiment of the present disclosure, with reference to the drawings. The embodiment shows one aspect of the present disclosure, but does not limit the present disclosure and can be modified as desired within the scope of the technical concept of the present disclosure.

[0010] (composition) The char bed detection device according to the present disclosure detects char bed accumulated in a furnace. Fig. 1 is a diagram schematically showing the configuration of a boiler 100 equipped with a char bed detection device 1 according to one embodiment. In one embodiment, the boiler 100 is a soda recovery boiler that burns black liquor F, which is a pulp cooking waste liquor (sodium-containing waste liquor) discharged from a paper mill or the like, as fuel, recovers heat generated by the combustion of the black liquor F, and recovers sodium components from the burned black liquor F.

[0011] As shown in FIG. 1, the boiler 100 includes a furnace 102, a supply device 104, a flue 106, a heat exchanger 108, a chimney 110, a char bed detection device 1 according to one embodiment, and a temperature adjustment device 112.

[0012] The furnace 102 has a cylindrical shape extending in the vertical direction D1, and has a combustion space 103 formed therein for burning black liquor F to generate combustion gas G. In the combustion space 103, solids contained in the black liquor F are deposited on the bottom surface 114 of the furnace 102, forming a char bed C. The shape of the char bed C changes depending on the combustion state of the black liquor F.

[0013] In the embodiment illustrated in FIG. 1, the furnace 102 includes a smelt recovery unit 120 that recovers smelt S produced by the combustion of black liquor F. The smelt S is a melt of black liquor F and contains sodium carbonate (Na2CO3), sodium sulfide (Na2S), and the like. In one embodiment, the smelt recovery unit 120 includes a discharge line 122 and a recovery tank 124. The discharge line 122 is a pipe that discharges the smelt S from the bottom surface 114 of the furnace 102. The recovery tank 124 stores the smelt S discharged from the discharge line 122. Note that the present disclosure is not limited to the embodiment of the smelt recovery unit 120 illustrated in FIG. 1.

[0014] The supply device 104 supplies black liquor F into the furnace 102 (combustion space 103). In one embodiment, the supply device 104 includes a black liquor supply source 130, a black liquor nozzle 132, and a black liquor line 134. The black liquor supply source 130 is, for example, a tank and stores black liquor F. The black liquor nozzle 132 is provided on the side wall 115 of the furnace 102 and is configured to spray the black liquor F in the form of particles into the combustion space 103. The black liquor line 134 connects the black liquor supply source 130 and the black liquor nozzle 132, and is configured to allow the black liquor F to flow from the black liquor supply source 130 to the black liquor nozzle 132.

[0015] The flue 106 connects the furnace 102 and the chimney 110, and is configured so that the combustion gas G flows from the furnace 102 toward the chimney 110. The heat exchanger 108 recovers heat from the combustion gas G by exchanging heat between the combustion gas G flowing through the flue 6 and steam or feedwater. Such a heat exchanger 108 is, for example, any one of a superheater, a reheater, an economizer, and an air preheater. The boiler 100 may include multiple heat exchangers 108. The chimney 110 discharges the combustion gas G (exhaust gas EG) from which the heat has been recovered to the outside of the boiler 100, such as into the atmosphere. The boiler 100 may further include a heat exchanger disposed in the combustion chamber 103 for recovering heat from the combustion gas G flowing through the combustion chamber 103.

[0016] The char bed detection device 1 detects char bed C accumulated in a furnace 102. The char bed detection device 1 includes an imaging device 2 and an identification device 4. The imaging device 2 captures successive images I of the char bed C in time series from the side wall 115 of the furnace 102. The imaging device 2 is arranged on the side wall 115 of the furnace 102 so that the surface 150 of the char bed C is included in the successive images I. In one embodiment, the imaging device 2 is a visible light camera. In one embodiment, the successive images I are video images lasting from 0.5 minutes to 5 minutes. The char bed detection device 1 may include multiple imaging devices 2, for example, four imaging devices 2 arranged to capture the char bed C from all sides. In some embodiments, the successive images I are still images in different time series.

[0017] The identifying device 4 identifies the surface position P of the char bed C based on the successive images I. In one embodiment, the identifying device 4 is electrically connected to the imaging device 2 and acquires the successive images I from the imaging device 2. The identifying device 4 is a computer such as an electronic control device, and includes a processor such as a CPU or GPU (not shown), memory such as a ROM or RAM, and an I / O interface. The identifying device 4 realizes each functional unit of the identifying device 4 by the processor operating (calculating, etc.) according to instructions of a program loaded into the memory. In some embodiments, the identifying device 4 is a cloud server provided in a cloud environment.

[0018] 2 is a schematic functional block diagram of a identifying device 4 according to an embodiment. As shown in FIG. 2, the identifying device 4 includes a grid creating unit 40, a variation calculating unit 42, and an allocating unit 44.

[0019] FIG. 3 is a diagram illustrating a grid 41 according to an embodiment. As shown in FIG. 3, the grid creation unit 40 creates multiple grids 41 by dividing consecutive images I along a vertical direction D1 and a horizontal direction D2, which intersects the vertical direction D1. The grid creation unit 40 creates multiple grids 41 common to at least two consecutive images (hereinafter referred to as frame images FI) that are in different time series from each other among the consecutive images I. The multiple grids 41 are formed within a predetermined range in the vertical direction D1 so that at least a portion of each grid 41 includes the surface 150 of the char bed C. The multiple grids 41 include multiple grid rows GL, each of which includes two or more grids 41 aligned in the vertical direction D1. The multiple grid rows GL are aligned in the horizontal direction D2. The grid 41 may have a rectangular shape or a square shape. The size of the grid 41 is not particularly limited and may be formed by one pixel or multiple pixels. In the present disclosure, "common" means that the positions of the grids 41 in the vertical direction D1 and the horizontal direction D2 are the same.

[0020] The variation calculation unit 42 calculates a variation V in color information based on a temporal change for each of the plurality of grids 41. In one embodiment, the color information is one of an R value, a G value, and a B value. In one embodiment, the variation V is a variance Vx,y. In some embodiments, the color information is determined to be one of an R value, a G value, and a B value depending on the color of the inner wall surface of the side wall 115 captured in the continuous images I. In the following description, it is assumed that an R value is applied to the color information, and that the color information is a numerical value between 0 and 255.

[0021] A method for calculating the variance Vx,y according to one embodiment will now be described in detail. FIG. 4 is a diagram illustrating the variance Vx,y according to one embodiment. As shown in FIG. 4, consecutive images I include a plurality of frame images FIn (n is an integer equal to or greater than 1). The variation calculation unit 42 acquires the R values ​​of each of the plurality of grids 41 created in each of the plurality of frame images FIn. The variation calculation unit 42 then calculates the variance Vx,y of the R values ​​of one common grid 41 for the plurality of frame images FIn. That is, the variance Vx,y of the R values ​​of one common grid 41 is calculated using the following equation 1: TIFF2025185512000002.tif16170V x,y is the variance and f x,y,i is the R value of the common grid 41 of the i-th frame image FI, and m x,y is the average value of the R values ​​of the common grid 41. Furthermore, x is the coordinate of the grid 41 in the left-right direction D2, y is the coordinate of the grid 41 in the up-down direction D1, and i represents the number of frame images FI. In the present disclosure, the x coordinate increases from left to right in the left-right direction D2, and the y coordinate increases from top to bottom in the up-down direction D1.

[0022] FIG. 5 is a diagram illustrating a flame region FR and a char bed region CR according to an embodiment. As shown in FIG. 5, the allocation unit 44 allocates each of the plurality of grids 41 to either a flame region FR having a large R-value variance Vx,y (variation V) or a char bed region CR having a small R-value variance Vx,y (variation V). In one embodiment, the allocation unit 44 allocates each of the plurality of grid arrays GL to a flame region FR and a char bed region CR located below the flame region FR. More specifically, the allocation unit 44 calculates a boundary coordinate y for each of the plurality of grid arrays GL. The allocation unit 44 then allocates an upper grid group G1, which includes two or more consecutive grids 41 included in one grid array GL and is located above the boundary coordinate y, to the flame region FR. Furthermore, the allocation unit 44 allocates a lower grid group G2, which includes two or more consecutive grids 41 included in this one grid array GL and is located below the boundary coordinate y, to the char bed region CR.

[0023] An example of a method for calculating the boundary coordinate y will be described. In one embodiment, the boundary coordinate y is calculated using the so-called Otsu's method, and in this Otsu's method, the value of y1 that minimizes Wx(y) in the following equation 2 is obtained as the boundary coordinate y. Note that the present disclosure is not limited to calculating the boundary coordinate y using the Otsu's method. TIFF2025185512000003.tif14170Wx(y) is the weighted sum of the variances Vx,y, and W x,0 (y) is the variance of the variance Vx,y corresponding to the flame region FR, and W x,1 (y) is the variance of the variance Vx,y corresponding to the char bed area CR. That is, W x,0 (y) is calculated by the following formula (3), and W x,1 (y) is calculated by the following equation (4): where a0 and a1 are weighting coefficients. TIFF2025185512000004.tif19170TIFF2025185512000005.tif17170Furthermore, m' x,0(y) is the average value of the variance Vx,y, calculated by the following formula (5), and m' x,1 (y) is the average value of the variance Vx,y and is calculated by the following equation (6). TIFF2025185512000006.tif19170TIFF2025185512000007.tif19170

[0024] Here, Y appearing in each of the formulas (4) and (6) is the number of grids 41 (grids 41 aligned in the vertical direction D1) included in one grid row GL. That is, as described above, W x,0 (y) corresponds to the flame region FR, and W x,1 (y) corresponds to the charbed region CR.

[0025] 6 is a graph showing the relationship between Wx(y) and the y coordinate of the grid 41, with the vertical axis representing Wx(y) and the horizontal axis representing the y coordinate of the grid 41. As shown in FIG. 6, Wx(y) is minimum at y1. This y1 is the boundary (boundary coordinate y) between the flame region FR and the char bed region CR. In other words, y1 is the surface position P of the char bed C. The y coordinate greater than y1 is the char bed region CR, and the y coordinate smaller than y1 is the flame region FR.

[0026] In one embodiment, the char bed detection device 1 detects the surface shape Cs (ridge line) of the char bed C by connecting together the surface positions P of the char bed C calculated for each of the plurality of grid rows GL. Although not shown, in some embodiments, the char bed detection device 1 further includes a monitor that displays the surface shape Cs of the char bed C identified by the identification device 4.

[0027] 1, the boiler 100 includes a temperature adjustment device 112 provided in the black liquor line 134. The temperature adjustment device 112 is configured to adjust the temperature of the black liquor F supplied to the furnace 102 based on the height position of the char bed C detected by the char bed detection device 1. The temperature adjustment device 112 may heat the black liquor F flowing through the black liquor line 134 with steam or cool it with feedwater.

[0028] The temperature adjustment device 112 is electrically connected to the identification device 4 and acquires the surface shape Cs of the char bed C from the identification device 4. The temperature adjustment device 112 increases the temperature of the black liquor F when the highest part of the surface shape Cs of the char bed C exceeds a preset upper limit position. The temperature adjustment device 112 decreases the temperature of the black liquor F when the highest part of the surface shape Cs of the char bed C is located below a preset lower limit position.

[0029] Although not shown, in some embodiments, the identification device 4 further includes an exclusion unit that excludes frame images FI that include unintended obstacles (e.g., a lens of a visible light camera or a cleaning tool cleaning a window on the side wall 115 of the furnace 102) from the series of images I.

[0030] (Actions and Effects) The operation and effect of the char bed detection device 1 according to one embodiment will be described. Black liquor F supplied into the combustion chamber 103 burns, forming a flame FL above the surface 150 of the char bed C (see FIG. 1). Because the flame FL flickers, even when the flame FL is being imaged, the side wall 115 behind the flame FL may be captured in the consecutive images I. This results in a large variance Vx,y of the R value. On the other hand, because the char bed C rarely flickers like the flame FL, when the char bed C is being imaged, it is rare for anything other than the char bed C to be captured. This results in a small variance Vx,y of the R value.

[0031] According to one embodiment, the imaging device 2 is a visible light camera that can capture continuous images I from which the R value can be obtained. Therefore, costs can be reduced compared to conventional char bed detection devices that use an infrared camera or a radiation thermometer to detect char beds C.

[0032] If the color of the inner wall surface of the side wall 115 is red, the difference in value is clearer in the variance Vx,y of only the R value than in the variance Vx,y that includes the R value, the G value, and the B value. According to one embodiment, the color information is one of the R value, the G value, and the B value. Therefore, it is possible to calculate a variance Vx,y with a clearer difference in value compared to when the color information is two or more of the R value, the G value, and the B value, thereby improving the detection accuracy of the char bed C. In some embodiments, the color information is two or more of the R value, the G value, and the B value.

[0033] Note that the present disclosure does not limit the color information to RGB values. In some embodiments, the color information is one of C, M, Y, and K values. Furthermore, the color information may be something other than color, such as brightness or saturation. If the color information is brightness, the image capture device 2 may be a brightness meter.

[0034] As described above, the char bed detection device 1 according to the present disclosure utilizes the flickering of the flame FL. Therefore, it is desirable that the continuous images I are continuous in time series so that the sidewall 115 is captured. According to one embodiment, the continuous images I are moving images of 0.5 minutes or more and 5 minutes or less, so that the difference between the variance Vx,y of the R values ​​in the flame region FR and the variance Vx,y of the R values ​​in the char bed region CR becomes clear, and the surface shape Cs of the char bed C can be detected with high accuracy.

[0035] According to one embodiment, the surface shape Cs of the char bed C can be easily detected by applying the variance Vx,y to the variance V. Note that the present disclosure does not limit the variance V to the variance Vx,y. The variance V may be something other than the variance Vx,y, for example, a standard deviation.

[0036] According to one embodiment, the surface position P of the char bed C, which is the boundary between the flame region FR and the char bed region CR, is acquired for each of multiple grid rows GL, and the surface shape Cs of the char bed C can be acquired by connecting multiple surface positions P together.

[0037] When a typical binarization method such as discriminant analysis (Otsu's binarization method), mode method, or P-tile method is applied to the variance Vx,y of the R values, multiple boundaries between the flame region FR and the char bed region CR may be detected within one grid row GL due to the influence of noise such as flickering flames FL. This can make it difficult to obtain the surface shape Cs of the char bed C. According to one embodiment, Otsu's method is used to calculate one boundary coordinate y that is most likely to be the surface position P of the char bed C for each grid row GL. This suppresses the influence of noise, making it possible to obtain the surface shape Cs of the char bed C.

[0038] For example, the combustion state of the black liquor F differs between the central portion of the combustion chamber 103 and the adjacent portion that is closer to the side wall 115 than the central portion. In other words, the manner in which the flame FL is formed differs between the central portion and the adjacent portion of the combustion chamber 103. According to one embodiment, the boundary coordinate y is calculated for each grid row GL to obtain the boundary between the flame region FR and the char bed region CR, thereby improving the detection accuracy of the surface shape Cs of the char bed C.

[0039] 1, the boiler 100 includes the char bed detection device 1 according to one embodiment, which reduces the cost of the device installed to detect the surface shape Cs of the char bed C. In addition, the boiler 100 is provided with a temperature adjustment device 112, which allows the height position of the char bed C to be adjusted to a desired position according to the surface shape Cs of the char bed C detected by the char bed detection device 1, thereby optimizing the operating condition of the boiler 100.

[0040] The contents described in each of the above embodiments can be understood, for example, as follows.

[0041] [1] The char bed detection device (1) according to the present disclosure is A char bed detection device for detecting a char bed (C) accumulated in a furnace (102), an imaging device (2) for capturing time-series consecutive images (I) of the char bed from the side wall (115) of the furnace; and an identification device (4) for identifying the surface position (P) of the char bed based on the continuous images, The specific device is a grid creating unit (40) that creates a plurality of grids (41) by dividing the continuous image along a vertical direction (D1) and a cross direction (D2) that crosses the vertical direction; a variation calculation unit (42) that calculates a variation (V) of color information based on a time change for each of the plurality of grids; and an allocating unit (44) that allocates each of the plurality of grids to either the flame region (FR) where variation is large or the char bed region (CR) where variation is small.

[0042] According to the configuration described in [1] above, the imaging device only needs to be capable of capturing continuous images from which color information can be obtained, and for example, a visible light camera or a brightness sensor can be applied. Therefore, costs can be reduced compared to conventional char bed detection devices that use an infrared camera or a radiation thermometer to detect char beds.

[0043] [2] In some embodiments, in the configuration described in [1] above, The imaging device is a visible light camera.

[0044] According to the configuration described in [2] above, the cost of the char bed detection device can be reduced compared to the conventional case.

[0045] [3] In some embodiments, in the configuration described in [2] above, The color information is one of an R value, a G value, and a B value.

[0046] If the color of the furnace wall is red, the difference in value is clearer in the variation of the R value alone than in the variation of the R value including the G value and the B value. According to the configuration described in [3] above, it is possible to calculate the variation of color information with a clearer difference in value compared to when the color information is two or more of the R value, G value, and B value, so the accuracy of char bed detection can be improved.

[0047] [4] In some embodiments, in the configuration described in any one of [1] to [3] above, The continuous images are moving images of 0.5 minutes or more and 5 minutes or less.

[0048] The char bed detection device detects char beds by utilizing the flickering of flames. Therefore, it is desirable that the continuous images are continuous in time series so that the wall surface of the furnace is captured. According to the configuration described in [4] above, the difference in values ​​between the variation in color information in the flame region and the variation in color information in the char bed region becomes clear, allowing for accurate detection of char beds.

[0049] [5] In some embodiments, in the configuration described in any one of [1] to [4] above, The variation is the variance (Vx, y).

[0050] According to the configuration described in [5] above, char beds can be easily detected.

[0051] [6] In some embodiments, in the configuration described in any one of [1] to [5] above, the plurality of grids include a plurality of grid rows (GL) in which two or more of the grids are aligned in a line along the vertical direction, The plurality of grid rows are aligned along the intersecting direction.

[0052] According to the configuration described in [6] above, the boundary between the flame region and the char bed region can be obtained for each of multiple grid rows, and the surface shape of the char bed can be obtained by connecting multiple boundaries with each other.

[0053] [7] In some embodiments, in the configuration described in [6] above, The allocation unit calculates boundary coordinates for each of the plurality of grid rows, and allocates two or more consecutive upper grid groups included in the grid row that are located above the boundary coordinates to the flame region, and allocates two or more consecutive lower grid groups included in the grid row that are located below the boundary coordinates to the char bed region.

[0054] According to the configuration described in [7] above, the boundary coordinates are set to one, which suppresses the influence of noise such as flame flickering, making it possible to obtain the surface shape of the char bed.

[0055] [8] The boiler (100) according to the present disclosure includes: Furnace (102) and a supply device (104) for supplying black liquor into the furnace; The char bed detection device (1) according to any one of [1] to [7] above, and a temperature adjusting device (112) that adjusts the temperature of the black liquor based on the height position of the char bed detected by the char bed detecting device.

[0056] According to the configuration described in [8] above, the cost of the char bed detector to be installed in the boiler can be reduced. In addition, since a temperature adjustment device is provided, the height position of the char bed can be set to a desired position. [Explanation of symbols]

[0057] 1. Charbed detector 2. Imaging device 4 Specific equipment 40 Grid Creation Section 41 Grid 42 Variation calculation section 44 Allocation Section 100 boiler 102 Furnace 103 Combustion space 104 Feeding device 106 Flue 108 Heat exchanger 110 Chimney 112 Temperature adjustment device 114 bottom 115 Side wall 120 Smelt Recovery Section 122 Discharge Line 124 Recovery Tank 130 Black liquor source 132 Black liquor nozzle 134 Black Liquor Line 150 Charbed Surface C Charbed CR charbed area Cs surface shape D1 Vertical direction D2 Left / right direction EG exhaust gas F Black liquor FI frame image FIn nth frame image FL flame FR flame area G Combustion gas GL Grid Columns I Continuous images P Charbed surface position S Smelt V Variation Vx,y variance

Claims

1. A char bed detection device for detecting char beds accumulated in a furnace, an imaging device that captures successive images of the char bed in time series from the side wall side of the furnace; and an identification device for identifying the surface position of the char bed based on the continuous images, The specific device is a grid creating unit that creates a plurality of grids by dividing the continuous images along a vertical direction and along an intersecting direction intersecting the vertical direction; a variation calculation unit that calculates a variation in color information based on a time change for each of the plurality of grids; an allocating unit that allocates each of the plurality of grids to either the flame region having large variation or the char bed region having small variation, Charbed detection device.

2. The imaging device is a visible light camera.

10. The char bed detection device of claim 1.

3. the color information is one of an R value, a G value, and a B value; 3. The char bed detection device of claim 2.

4. The continuous images are moving images of 0.5 minutes or more and 5 minutes or less.

4. A char bed detection device according to any one of claims 1 to 3.

5. The variation is a variance.

4. A char bed detection device according to any one of claims 1 to 3.

6. the plurality of grids include a plurality of grid rows in which two or more of the grids are aligned in a line along the vertical direction; the plurality of grid rows are aligned along the cross direction; 4. A char bed detection device according to any one of claims 1 to 3.

7. the allocating unit calculates boundary coordinates for each of the plurality of grid rows, and allocates an upper grid group including two or more consecutive grids included in the grid row and located above the boundary coordinates to the flame region, and allocates a lower grid group including two or more consecutive grids included in the grid row and located below the boundary coordinates to the char bed region.

7. The char bed detection device of claim 6.

8. The furnace and a supply device for supplying black liquor into the furnace; A char bed detection device according to any one of claims 1 to 3; and a temperature adjusting device that adjusts the temperature of the black liquor based on the height position of the char bed detected by the char bed detecting device. Boiler.

Images