CN115899710A - Method for operating a furnace unit - Google Patents

Abstract

A method for operating a furnace unit having a feed chute and a camera for capturing images of the chute surface provides for the chute to comprise a chute over which material flows to a grate, and for the image evaluation to determine the coverage of the chute and in particular the chute covered by material, the combustion bed thickness and the burnout zone.

Description

Method for operating a furnace unit

Technical Field

The invention relates to a method for operating a furnace unit. Importantly, when the furnace unit is operated, a defined amount of material per unit time passes through the furnace unit, from the feed chute through the grate of the furnace to the bottom ash discharge opening.

Background

During the feeding operation, the hopper on the feeding chute is filled with material by means of the jaws. This material is a substance that can undergo chemical transformation with a positive energy balance and is preferably waste in the context of the present application. This material may be wet and heavy and slides quickly into the hopper; it may stick to the hopper walls, become stuck in the hopper, or otherwise fail to reach the grate area of the furnace in a continuous manner via the hopper.

The material ignites on the grate of the furnace and burns with variable intensity and heat release depending on the composition of the waste. When multiple grates are operated in close proximity to each other, the possibility also exists that: as the refuse moves on different grate tracks, the refuse is also burned in a variable manner.

In many cases the function of the furnace unit, in particular the function of the waste incineration plant, is to dispose of the waste in an environmentally friendly manner with as low emissions as possible and to generate energy. For this purpose, the heat release should be as constant as possible in order to achieve controlled incineration on the one hand and to provide a constant steam output which is as constant as possible on the other hand.

Disclosure of Invention

The invention is therefore based on the object of keeping the finally produced furnace output, which is usually reflected in the steam output, as constant as possible.

This object is achieved by a method for operating a furnace unit having a feed chute and a camera for capturing images of the chute surface, characterized in that the chute comprises a chute on which material flows to a grate, and in that the change in position and hence the movement of the chute and in particular the coverage of the chute by the material and/or individual components or surface areas within the chute is determined by means of an image evaluation device.

The chute here is a feeding chute surface inclined with respect to the vertical. The chute may be the bottom or lateral surface of a feed chute along which material placed onto the chute slides in order to reach the furnace unit.

If the wall material of the chute (which is usually a ferrous surface) is covered in a certain area and the wall material is static or the coverage varies depending on the movement of the pusher feeder, it can be assumed that the material is sliding correctly towards the oven unit. Movement of combustible material on the chute in the direction of the furnace is coupled with movement of the pusher feeder. If the latter moves, the material moves. If it does not move, the material does not move. If this relationship is not provided and the material is moving despite the feeder not moving, or the material is not moving despite the feeder moving, then there is a defect indicating that the material is not sliding correctly towards the furnace unit. Here, vertical wall areas or areas on the chute can be observed. The surface area of the chute is preferably observed, which forms part of the chute and has as small an angle as possible with respect to the horizontal, since the surface area detected in the event of a defective sliding is therefore larger.

As a result, the coverage of the chute bottom side covered by material is preferably evaluated, while the other sides of the chute generally constitute additional reference points.

A preferred embodiment provides that, in the image, the position of at least one boundary point is determined, at which the material covers the chute on one side and the surface of the chute is visible on the other side. Advantageously, a plurality of boundary points are determined, in which case the positions of the lines connecting the boundary points in the image can also be determined.

To determine the filling of the chute, defined points on the sides of the chute may also be calculated. In this case, the distance of at least one boundary point from a defined point on the chute side is determined.

In other words, it is advantageous to determine the visible line between the chute and the material. To improve the accuracy of the image evaluation, the image of the chute surface may be divided into a plurality of zones. This makes it possible to determine the coverage in the individual zones by means of the image evaluation device. The material flow at any point within the chute can be determined therefrom. When a plurality of images are taken over a time interval, the dynamic behavior of the furnace unit can be determined and the filling level in the chute is determined from the change in the images by means of the image evaluation device. This therefore also makes it possible to determine the rate of material flow to the furnace unit from the change in the image. This rate then constitutes the possibility of also measuring the amount of material flowing to the grate.

Furthermore, changes in the position and thus movement of individual components or surface areas within the chute can be tracked by means of imaging techniques. It is necessary to take a plurality of images within a time interval. These images may be taken as separate images or as movies. After introducing the materials and detecting their movement (until the selected component is covered), a significant component or surface area is selected within the chute. The selection is made in an automated manner and may be based on structures and objects learned by means of artificial intelligence, on the salient shape, color or contour of the material within the chute, or on random or defined areas within the chute. This method allows the material flow within the chute to be determined, as does the method of detecting individual points at the transition between the chute and the material. The method may be performed alone or in addition to detecting a single point at the transition between the chute and the material.

Defects detected in the area of the feed chute often directly lead to defects in the burning on the grate. Thus, as a further embodiment, it is proposed to trigger an action in case of a predetermined coverage or a predetermined change of coverage of the chute and in particular the chute by material or a specific material flow depending on the movement of the feeder. This action may be an early intervention in the unit adjustment. For example, a purge stroke may be initiated at this point, or in the event of uncontrolled waste flow, adjustments may be made by air management and/or grate speed. In order to optimize the incineration, it is also possible to intervene on the speed and/or position of the feeder in the case of uncontrolled waste flow. In addition, an auxiliary function (signal to the crane operator) or a direct intervention by the crane on the material supply of the chute as a function of the detected chute filling level is possible.

The use of an image evaluation device makes it possible to determine the transition from the material to the background at the end of the image in the direction of flow of the material as the location of at least one point and preferably on the line. Alternatively or in addition to the coverage of the chute, it is therefore possible, in the case of a stationary arrangement of the camera, to evaluate the height of the line on the determined image, which can be determined by the transition from material to chute. For this purpose, individual points or continuous lines can be determined, which can also be averaged.

As a further example, this allows a point or line to be compared with a limit value and an action to be triggered in case the limit value is exceeded. This action corresponds to the action mentioned above.

However, the results also show that the furnace unit can be controlled using the image evaluation device not only at the feed chute but also at the end of the grate of the furnace.

Furnace units with a grate having a camera arranged on its end are known. The end of the grate constitutes an area where bottom ash accumulates on the grate. A camera positioned here is directed from the bottom ash region to the combustion bed, showing how the material is burning in the combustion bed. The intensity here shows the intensity of burn-out and the location of the intensity shows where the material burns particularly well on the grate.

According to the invention, it is further proposed to combine the camera with an image evaluation device which determines the combustion bed thickness and/or the burnout line and/or the movement of individual components or surface areas. Using a stationary camera, the image shows the combustion bed and static features within the furnace. The static characteristic and the distance between the combustion beds is proportional to the height of the combustion beds. Too high a combustion bed indicates an operation where too much material is moved by feed or too little refueling that causes the material to move too slowly. From the low line in the image a particularly low combustion bed can be deduced, which indicates a material supply where not enough material is moved by the feed and/or by the refuelling which is too violent, which moves the material too fast.

Furthermore, it is proposed to combine the camera with an image evaluation device which determines the burnout line. Using a stationary camera, the image shows the transition between burning and burnout material as a burnout line. In practice, this contrast constitutes a line that is either closer to the upper edge of the image taken by the camera or closer to the lower edge of the image. Thus, the height of the line is proportional to the location of the fire. A fire that is too long in the longitudinal extension of the grate indicates a supply of material in which too much material is fed or in which the material does not burn well. From the images it can be concluded that a particularly short fire indicates a supply of material in which not enough material has been fed. Furthermore, the variation of the burnout line allows inferences about the refuelling action of the grate and the primary air management, so that these parameters can be adjusted in order to improve the incineration. The burnout line also allows for the uniformity of the amount of combustible material between different grate tracks.

In addition, the movement of individual components or sections within the combustion bed may be tracked by means of imaging techniques. Part of this is the surface area that is detectable due to its structure, or the surface area that is selected as the surface area. It is necessary to take a plurality of images within a time. After introducing the material, significant parts or portions are selected within the combustion bed and their movement is detected until the selected parts are covered. The selection is done in an automated manner and may be based on structures and objects learned by means of artificial intelligence, on the salient shape, color or contour of the material within the chute, or on random or defined areas within the chute. The method allows determining the material flow within the combustion bed. The method may be implemented alone or in addition to detecting the height of the combustion bed and the length of the fire.

In this way, the image evaluation means at the end of the grate allows to draw inferences about the feeding means.

Thus, with a well-tuned image evaluation device, and preferably also with a learning system such as e.g. a neural network, it is possible to detect too thin or too thick combustion beds and too long or too short fires, i.e. incorrect positions of the burnout wire.

This information may be compared to a target value so that an action may be triggered depending on the location of the fire and/or the combustion bed thickness and/or the movement of the individual components or surface areas. This action, in turn, can interfere with the transport or gas ratios on the grate, as described above. As a further embodiment, it is therefore proposed that the intervention of the control or regulation of the furnace unit takes place automatically as a function of the position of the fire on the grate, in particular in the longitudinal direction of the grate, and/or as a function of the combustion bed thickness. It is therefore proposed to control or adjust the grate speed depending on the location of the fire and/or the combustion bed thickness. In this context, it is particularly advantageous to control or adjust the grate velocity of individual grate zones or adjacent grate tracks.

Additionally or alternatively, the gas flow of the furnace unit may also be controlled or adjusted depending on the combustion bed thickness and/or the position of the fire. In particular, in this context, the primary air of the furnace unit is controlled or regulated depending on the location of the fire and/or the combustion bed thickness.

It is particularly advantageous if the furnace comprises an individual grate rail which is analyzed by means of image evaluation, so that the feed of the individual grate rail can be controlled or adjusted depending on the combustion bed thickness and/or the position of the fire. To this end, for example, the stroke length may be adjusted or a zero offset setting of the feeder may be selected.

It is particularly advantageous if the individual grate tracks have a plurality of drives, so that the intensity of the refuelling movement of the individual grate zones can be controlled or adjusted as a function of the combustion bed thickness and/or the position of the fire. For this purpose, for example, the refueling speed can be adjusted.

The coupling of the two optical camera systems is advantageous. In this way, the intervention triggered by the camera above the chute can be checked by means of the camera at the end of the combustion bed. The triggered intervention can be optimized by means of a control loop or a neural network.

Even independently of the aforementioned method steps, a method for operating a furnace unit with at least one grate comprising a plurality of grate zones and/or a plurality of grate rails and a plurality of combustible material feeders is proposed, in which method, in order to establish a uniform heat release on the grate, the temperature of each grate zone and/or each grate rail is measured, and the combustible material feeders are controlled in dependence on the measured temperatures.

In this context, it is particularly advantageous to use at least one temperature measuring device per grate zone and/or per grate track. The temperature measurement can be performed parallel to the grate section or in the first waste flow conduit. In order to avoid that the accuracy of the temperature measurement is impaired by the turbulent air, it is proposed that the recording of the temperature change takes place in the vicinity of the furnace and at the latest at the level of the waste stream duct where the flue gas arrives after 1 to 15 seconds.

Drawings

Advantageous embodiment variants are shown in the drawings and described in more detail below, wherein:

FIG. 1 schematically illustrates a grate furnace in which the temperatures on the chute A, fire B and grate track C are analyzed;

FIG. 2 shows a cross section through a feed chute region of a furnace unit;

FIG. 3 is a top plan view of the chute shown in FIG. 2;

FIG. 4 is an enlarged view from FIG. 3;

fig. 5 shows an image taken by the camera arranged at B in fig. 1;

figure 6 shows a furnace unit with two waste flow conduits;

fig. 7 illustrates the furnace unit shown in fig. 6 in a perspective view.

Detailed Description

The furnace unit 1 shown in fig. 1 is a grate furnace with a grate 2, below which grate 2 a primary air supply 3 is arranged. The material 4 combusted on the grate 2 is transported on the grate 3 to a bottom ash discharge opening 5. Flue gas 6 generated during incineration of the material 4 on the grate 2 reaches the first duct 7 and from there flows into further ducts 8 and 9 in order to heat water, which is used as steam for an energy generating unit (not shown).

During operation of the furnace unit 1, waste is passed as material 4 from the chute 10 through the feed channel 11 to the grate 2 and from there to the bottom ash discharge opening 5. In the process, a camera 12 is used to capture the surface 13 of the chute and depict it as an image 14.

An additional camera 34 located at the end 15 of the grate 2 is directed at the material 4 on the grate 2 and the flame 16 generated by the combustion of the material 4. Between them, the flame 16 generated on the grate 2 can be observed from above by a third camera 17.

Fig. 2 shows how the material 4 can be thrown into the feed chute 10 by means of the jaws 20 and then run on the chute 21 into the channel 4 and from there to the furnace grate 2 of the furnace.

The camera 12 is connected to an image evaluation device 22, the image evaluation device 22 determining the coverage of the chute 10 and in particular the chute 21 with the material 4.

Fig. 3 and in particular into the enlarged view of fig. 3 shown in fig. 4, show the area 23 and the area 24 in which the chute 21 is covered by the material 4, and the area 43 in which the upper side of the chute 21 is visible, since it is not covered by the material 4 in this area 24.

The rods 25, 26 and 27 constitute boundary points in the image 4 where the material 4 covers the chute 10 on one side and the surface of the chute 10 is visible on the other side.

The defined points 29, 30 and 31 are indicated as vertical bars on the side 28 of the chute 10. This makes it possible to determine the points of intersection between the horizontal bars 25, 26 and 27 and the vertical bars 29, 30 and 31 in order to deduce therefrom the filling of the chute 10.

In the image 14 of fig. 3, the line 33 shows the transition between the material 4 and the background 33. The height of this line 33 in the image 4 and the deviation from a straight line provide information about the material in the chute 10.

Fig. 5 shows an image 35 taken with the camera 14 at the end of the grate 2 in the direction of flow of the material 4. From this image 35, the image evaluation device 36 determines the combustion bed thickness 37 as the distance between the line 38 and the line 41. The line 38 results from the contrast between a bright area 39 of the flame 16 and a dark area 40 of bottom ash. The height of the lines 41 in the image 35 can be determined by testing and also appear in cells on the grate 2 that do not yet have any material 4.

The image evaluation devices 22 and 36 are connected to a control system 41 of the furnace unit 1 such that, if a limit value is exceeded, an adjustment 41 of the furnace unit can be intervened in order to control or adjust the grate speed and/or the air supply of the furnace unit 1 as a function of the limit value detected at the chute 10 and/or the combustion bed thickness 37.

Fig. 6 shows the grate 2 of the furnace and the first flue gas duct 7 located above the grate 2 of the furnace, followed by the second flue gas duct 8. Parallel to the grate 2 or horizontally, a temperature measuring device 49 is arranged. Thereby producing a temperature measurement level 52 above the secondary air level 54. Fig. 7 shows a schematic arrangement of a temperature measuring device for a unit having 3 grate rails 46, 47 and 48. Each grate rail is associated with a temperature measuring device 49, 50, and 51.

Claims (26)

1. A method for operating a furnace unit (1), the furnace unit (1) having a feed chute (10) and a camera (12) for capturing an image (14) of the surface (13) of the chute (10), characterized in that the chute (10) comprises a chute (21), on which chute (21) material (4) flows towards a grate (2), and that the coverage of the chute (10) and in particular of the chute (21) by material (4) and/or the change of position and thus the movement of individual components or surface areas (42) within the chute are determined by means of an image evaluation device (22).

2. Method according to claim 1, characterized in that in the image (14) the position of at least one boundary point (25, 26, 27) is determined, at which position the material (4) covers the chute (10) on one side and the surface (43) of the chute (10) is visible on the other side.

3. Method according to claim 2, characterized in that the boundary points (25, 26, 27) are determined in the area of the slide (10).

4. A method according to claim 2 or 3, characterized by determining a plurality of boundary points (25, 26, 27).

5. Method according to claim 4, characterized in that the position of the line connecting the boundary points (25, 26, 27) in the image is determined.

6. A method according to any one of claims 2 to 5, characterized by determining the distance of at least one boundary point (25, 26, 27) from a defined point (29, 30, 31) on a side (28) of the chute (10).

7. The method according to any one of claims 2 to 4, characterized by determining a visible line between the chute (10) and the material (4).

8. The method according to any one of claims 1 to 7, characterized in that the image (14) of the surface of the chute (10) is divided into a plurality of zones (25, 26, 27, 28, 29) and the coverage in the individual zones (25, 26, 27, 28, 29) is determined by means of an image evaluation device (22).

9. Method according to any one of the preceding claims, characterized in that a plurality of images (14) or videos are taken over a time interval and the filling level in the chute (10) is determined from the change of the images (14) by means of an image evaluation device (22).

10. The method of claim 9, wherein the rate at which the material (4) flows toward the grate (2) is determined based on a change in the image (14).

11. Method according to any one of claims 1 to 10, characterized in that an action is triggered in the case of a predetermined coverage or a predetermined change in coverage of the chute (10) and in particular of the chute (21) by the material (4) or a specific material flow depending on the movement of the feeder.

12. Method according to any one of claims 9 to 11, characterized in that the transition from the material (4) to the background (32) is determined as the position of at least one point in the flow direction of the material (4), and preferably the position of a line (33), at the end of the image (14).

13. Method according to claim 12, characterized in that the point or line (33) is compared with a limit value and an action is triggered in case the limit value is exceeded.

14. The method according to any of the preceding claims, characterized in that the refuse quality and/or refuse composition is determined from the image (14) of the surface (13) of the chute (10) by means of a learning system, such as a neural network.

15. A method for operating a furnace unit, in particular according to any of the preceding claims, comprising a grate (2) on the end (15) of which a camera (14) is arranged, characterized in that the combustion bed thickness (37) and/or the burnout line (38) and/or the movement of individual components or surface areas are determined by an image evaluation device (36).

16. The method according to claim 15, characterized in that an overfilled combustion bed is detected by means of an image evaluation device (36) by means of a learning system, such as a neural network, or via the characteristic shape of the burnout wire (38).

17. A method according to claim 15 or 16, characterized in that the action is triggered in dependence of the combustion bed thickness (37) and/or the burnout line (38) and/or the movement of a separate component or surface area.

18. Method according to any of claims 15-17, characterized in that the control (41) or regulation of the furnace unit (1) is automatically intervened according to the combustion bed thickness (37) and/or the burnout line (38) and/or the movement of the individual components or surface areas.

19. A method according to any one of claims 15-18, c h a r a c t e r i z e d in that the grate speed is controlled or adjusted in dependence of the combustion bed thickness (37) and/or the burnout line (38) and/or the movement of separate parts or surface areas.

20. The method according to any of the claims 15 to 19, characterized in that the air supply (3) of the furnace unit (1) is controlled or adjusted according to the combustion bed thickness (37) and/or the burnout line (38) and/or the movement of the individual components or surface areas.

21. Method according to claim 20, characterized in that the primary air (3) of the furnace unit (1) is controlled or regulated in dependence of the combustion bed thickness (37) and/or the burnout line (38) and/or the movement of individual components or surface areas.

22. Method according to any of claims 15-21, characterized in that the feeding of the individual grate rails (46, 47, 48) of the furnace unit (1) is controlled or adjusted according to the combustion bed thickness (37) and/or the burnout line (38) and/or the movement of individual parts or surface areas.

23. Method for operating a furnace unit (1) with at least one grate (2), in particular according to any of the preceding claims, comprising a plurality of grate zones and/or a plurality of grate tracks (46, 47, 48) and a plurality of combustible material feeders (45), characterized in that, in order to establish a uniform heat release on the grate (2), the temperature of each grate zone and/or each grate track (46, 47, 48) is measured and the combustible material feeder (45) is controlled depending on the measured temperature.

24. A method according to claim 23, characterized in that at least one temperature measuring device (49, 50, 51) is used per grate zone and/or per grate track (46, 47, 48).

25. The method according to any of the preceding claims, wherein the temperature measurement is performed parallel to the grate (2).

26. A method according to any of the preceding claims, characterized in that the temperature measurement takes place in the first waste stream conduit (7).

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