JP6880142B2 - Combustion status evaluation method and combustion control method - Google Patents

Description

The present invention mainly relates to a method for evaluating a combustion state in order to appropriately maintain stable combustion in a grate-type incinerator that incinerates waste while transporting it by a grate.

Since a wide variety of wastes are put into the incinerator, it is important to be able to properly maintain stable combustion even if the properties of the put wastes change. In addition, the grate-type waste incinerator is divided into a drying section for drying the waste, a combustion section for burning the waste with flame, and a post-combustion section for post-combusting the waste (Oki combustion). There is. In order to perform combustion control for appropriately maintaining stable combustion, it is important to keep the position of the burnout position, which is the end position of such flame combustion, within an appropriate range.

It should be noted that (1) the main reason why the position of the burnout position deviates from the appropriate range is that there is a difference between the assumed drying time and the actual drying time due to the difference in the properties of the waste, (2). Therefore, the position of the burnout position should be controlled based on the change information of the combustion position and the burnout position where the state change appears after a considerable time delay after the difference between the assumed drying time and the actual drying time occurs. Is difficult in reality, (3) The direction of movement of the combustion start position tends to be the difference between the assumed drying time and the actual drying time (that is, the appropriateness of the progress of waste drying and combustion). Considering that it can be treated as information necessary to keep the burnout position within an appropriate range, etc., various types of drying progress in the waste accumulated in the grate of the dry part The information can be treated as information for keeping the position of the burnout position within an appropriate range.

In the method of Patent Document 1, an infrared camera is used to acquire a thermal image of waste in a dry portion. In the method of Patent Document 2, a thermal image of a dry portion is acquired by using an infrared camera equipped with a filter for blocking infrared rays emitted by a flame and an infrared camera not equipped with this filter. Then, the upstream end of the region where the temperature difference is detected in the two thermal images is specified as the ignition start region. In the method of Patent Document 3, a visible image of a dry portion is acquired using a visible image camera, and the visible image is analyzed to identify a combustion start position in the dry portion. The method of Patent Document 4 describes that a three-dimensional visible image of a dry portion is created by using a plurality of visible image cameras, and a combustion start position is specified based on a flame appearing in the three-dimensional visible image. Further, in the method of Patent Document 4, the time change of the thickness of the waste and the time change of the surface movement speed are calculated based on the three-dimensional visible image, and the progress of drying is estimated based on these. Is described.

JP-A-2017-116252 Japanese Patent No. 3315036 Japanese Unexamined Patent Publication No. 2019-52222 Japanese Patent No. 6543389

Patent Document 1 does not describe a specific method for specifying the combustion start position based on a thermal image. In Patent Document 2, an infrared camera equipped with a filter mainly contains information other than flame (that is, waste), while an infrared camera not equipped with a filter mainly contains information related to flame. Therefore, even if these two thermal images are compared, it is difficult to accurately identify the position where the flame is generated. In Patent Documents 3 and 4, the combustion start position is specified only based on the flame appearing in the visible image. However, the combustion start position thus identified does not accurately indicate "the position where the dry state in which drying is progressing is switched to the thermal decomposition state in which thermal decomposition is progressing". This is because, in order for combustion to occur, it is not enough to switch to a state in which thermal decomposition is in progress, and it is necessary to have a condition that a sufficient amount of oxygen is continuously present. In addition, since the amount of oxygen and temperature in the space directly above the waste fluctuate depending on the situation, there is a gap between the "position where the dry state is switched to the thermal decomposition state" and the position where combustion is occurring. Therefore, it is not possible to evaluate the amount of this deviation. It should be noted that Patent Documents 3 and 4 do not describe specifying the combustion start position based on the time change of the thickness and the time change of the surface movement speed.

The present invention has been made in view of the above circumstances, and its main purpose is to accurately evaluate the position where combustion has started in the entire incinerator based on a visible image obtained by using a visible light camera. To provide a method.

The problem to be solved by the present invention is as described above, and next, the means for solving this problem and its effect will be described.

From the viewpoint of the present invention, the following combustion condition evaluation method is provided. That is, this combustion condition evaluation method is divided into a dry part, a combustion part, and a post-combustion part, and incinerator provided with a grate for transporting the waste by operating intermittently in a state where the waste is accumulated. Performed on the incinerator. This combustion state evaluation method includes a production step, a division step, a flame determination step, a first calculation step, a second calculation step, a third calculation step, a state determination step, and an evaluation step. In the production step, a plurality of visible light cameras are used to observe the flame and at least the waste deposited on the dry portion, a plurality of visible images having different viewpoints are acquired, and the plurality of visible images are based on the plurality of visible images. Create a three-dimensional visible image. In the division step, the waste of the three-dimensional visible image is mesh-divided into a plurality of elements. In the flame determination step, it is determined for each element whether or not a flame is generated from the waste based on the three-dimensional visible image. In the first calculation step, the thickness of the waste and the surface moving speed of the waste are calculated for each of the elements based on the three-dimensional visible image. In the second calculation step, based on the calculation result of the first calculation step, the thickness elapsed indicating how the thickness of the waste located in the element changed in time series until it was located in the element. Information is calculated for each of the elements. In the third calculation step, based on the calculation results of the first calculation step and the second calculation step, how the volume flow rate before the waste located in the element is located in the element is in chronological order. Volumetric flow rate progress information indicating whether or not the change has occurred is calculated for each of the above elements. In the state determination step, the volumetric flow rate progress information is analyzed, and it is determined for each of the elements whether or not the waste is in a combustion startable state indicating a state in which the waste has shifted from a dry state to a thermal decomposition state. In the evaluation step, the combustion start evaluation position, which is an index of the position where combustion is started in the incinerator as a whole and is a position for evaluating combustion, is specified based on the judgment results of the flame judgment step and the state judgment step. To do.

As a result, the combustion start position is evaluated based on both the position where combustion can be started and the position where combustion is determined to have started based on the flame, so that the state of waste and combustion can be more accurately determined. Can be evaluated. In particular, since the combustion start evaluation position is specified based on how the volumetric flow rate of the waste has changed over time, the combustion start evaluation position can be specified with high reliability.

According to the present invention, it is possible to accurately evaluate the position where combustion has started in the entire incinerator based on a visible image obtained by using a visible light camera.

The schematic block diagram of the waste incinerator including the incinerator which performs the method of this invention. Functional block diagram of the incinerator. A three-dimensional schematic view of an incinerator showing the mounting position of a visible light camera. A flowchart showing a part of the control performed by the control device to stabilize combustion. A flowchart showing the rest of the control performed by the controller to stabilize combustion. Perspective view showing waste thickness, surface moving speed, and mesh division. The figure explaining the thickness progress information. The figure explaining the volume flow rate progress information. The plan view which explains the judgment result about the combustion start possible state and the flame generation start position, and the combustion start evaluation position. A schematic configuration diagram of a waste incineration facility showing the state when the combustion start position moves to the upstream side. A schematic configuration diagram of a waste incineration facility showing the state when the combustion start position moves to the downstream side.

<Overall Configuration of Waste Incinerator> First, the waste incinerator (waste incinerator) 100 including the incinerator (waste incinerator) 10 of the present embodiment will be described with reference to FIG. FIG. 1 is a schematic configuration diagram of a waste incinerator 100 including an incinerator 10 for performing the method of the present invention. In the following description, when the terms "upstream" and "downstream" are used, they mean upstream and downstream in the direction in which waste, combustion gas, exhaust gas, primary air, secondary air, circulating exhaust gas, etc. flow.

As shown in FIG. 1, the waste incinerator 100 includes an incinerator 10, a boiler 30, and a steam turbine power generation facility 35. The incinerator 10 incinerates the supplied waste. The detailed configuration of the incinerator 10 will be described later.

The boiler 30 uses the heat generated by the combustion of waste to generate steam. The boiler 30 generates steam (superheated steam) by exchanging heat between high-temperature combustion gas generated in the furnace and water in a large number of water pipes 31 and superheater pipes 32 provided on the flow path wall. The steam generated in the water pipe 31 and the superheater pipe 32 is supplied to the steam turbine power generation facility 35.

The steam turbine power generation facility 35 includes a turbine and a power generation device (not shown). The turbine is rotationally driven by steam supplied from the water pipe 31 and the superheater pipe 32. The power generation device uses the rotational driving force of the turbine to generate electricity.

Here, in order to generate stable power generation, it is necessary to stabilize the amount of steam (superheated steam) produced in the boiler 30. In order to stabilize the amount of steam (superheated steam) generated in the boiler 30, it is necessary to stabilize the heat input to the boiler 30. That is, in order to keep the amount of power generation constant, it is necessary to stabilize the amount of heat possessed by the combustion gas supplied from the incinerator 10 to the boiler 30 and keep the heat input to the boiler 30 stable.

<Structure of Incinerator 10> The incinerator 10 includes a dust supply device 40 for supplying waste into the furnace. The dust supply device 40 includes a waste input hopper 41 and a dust supply device main body 42. The waste input hopper 41 is a portion where waste is input from outside the furnace. The dust supply device main body 42 is located at the bottom of the waste input hopper 41 and is configured to be movable in the horizontal direction. The dust supply device main body 42 supplies the waste charged into the waste input hopper 41 to the downstream side. The movement speed of the dust supply device main body 42, the number of movements per unit time, the movement amount (stroke), and the position of the stroke end (movement range) are controlled by the control device 90. The dust supply device may be of a type that moves at a slight angle with respect to the horizontal direction.

The waste supplied into the furnace by the dust supply device 40 is supplied by the transport unit 20 in the order of the drying unit 11, the combustion unit 12, and the post-combustion unit 13. The transport unit 20 is composed of a dry grate 21 provided in the drying unit 11, a combustion grate 22 provided in the combustion unit 12, and a post-combustion grate 23 provided in the post-combustion unit 13. There is. Therefore, the transport unit 20 is composed of a plurality of stages of grate. Each grate is provided on the bottom of each part, and waste is placed on it.

The grate is composed of a movable grate and a fixed grate arranged side by side in the waste transport direction, and the movable grate operates in the order of forward, stop, reverse, stop, etc. to dispose of waste. The waste can be agitated while being transported to the downstream side. By increasing (decelerating) the operating speed of the movable grate, it is possible to increase (decelerate) the transport speed of waste. Further, by shortening (longening) the stop time of the movable grate, it is possible to increase (decelerate) the transport speed of waste. In addition, the grate is arranged side by side with a gap large enough for gas to pass through.

The drying unit 11 is a portion for drying the waste supplied to the incinerator 10. The waste of the drying unit 11 is dried by the primary air supplied from under the drying grate 21 and the radiant heat of combustion in the adjacent combustion unit 12. At that time, thermal decomposition gas is generated from the waste of the drying portion 11 by thermal decomposition. Further, the waste of the drying unit 11 is conveyed toward the combustion unit 12 by the drying grate 21.

The combustion unit 12 is a portion that mainly burns the waste dried by the drying unit 11. In the combustion unit 12, the waste mainly causes flame combustion to generate a flame. The waste in the combustion unit 12, the ash generated by combustion, and the unburned material that cannot be completely burned are conveyed toward the post-combustion unit 13 by the combustion grate 22. Further, the combustion gas and the flame generated in the combustion unit 12 pass through the throttle unit 17 and flow toward the post-combustion unit 13. The combustion grate 22 is provided at the same height as the dry grate 21, but may be provided at a position lower than the dry grate 21.

The post-combustion section 13 is a section that burns waste (unburned matter) that could not be completely burned by the combustion section 12. In the post-combustion unit 13, the radiant heat of the combustion gas and the primary air promote the combustion of the unburned material that could not be completely burned in the combustion unit 12. As a result, most of the unburned material becomes ash, and the unburned material decreases. The ash generated in the post-combustion unit 13 is conveyed toward the chute 24 by the post-combustion grate 23 provided on the bottom surface of the post-combustion unit 13. The ash conveyed to the chute 24 is discharged to the outside of the waste incineration facility 100. Although the rear combustion grate 23 of the present embodiment is provided at a position lower than the combustion grate 22, it may be provided at the same height as the combustion grate 22.

As described above, since the reactions that occur in the drying unit 11, the combustion unit 12, and the post-combustion unit 13 are different, the wall surfaces and the like are configured according to the reactions that occur. For example, since flame combustion occurs in the combustion unit 12, a structure having a higher refractory level than the drying unit 11 is adopted.

The reburning unit 14 is a part that burns the unburned gas contained in the combustion gas. The re-combustion unit 14 extends upward from the drying unit 11, the combustion unit 12, and the post-combustion unit 13, and secondary air is supplied in the middle thereof. As a result, the combustion gas is mixed and agitated with the secondary air, and the unburned gas contained in the combustion gas is burned in the reburning unit 14. The combustion generated in the combustion unit 12 and the post-combustion unit 13 is referred to as primary combustion, and the combustion generated in the recombustion unit 14 (that is, the combustion of the unburned gas remaining in the primary combustion) is referred to as secondary combustion.

The gas supply device 50 is a device that supplies gas into the furnace. The gas supply device 50 of the present embodiment includes a primary air supply unit 51, a secondary air supply unit 52, and an exhaust gas supply unit 53. Each supply unit is composed of a blower for attracting or sending out gas.

In the present specification, the gas supplied for primary combustion is referred to as a primary combustion gas. The primary combustion gas includes primary air, circulating exhaust gas, and a mixed gas thereof. The primary air is air taken in from the outside and is not used for combustion or the like (that is, excluding circulating exhaust gas). Therefore, the primary air also includes a gas obtained by heating the air taken in from the outside. Similarly, in the present specification, the gas supplied for secondary combustion is referred to as a secondary combustion gas. The secondary combustion gas includes secondary air, circulating exhaust gas, and a mixed gas thereof. The definition of secondary air is similar to that of primary air.

The primary air supply unit 51 supplies the primary air into the furnace via the primary air supply path 71. The primary air supply path 71 is branched into a first supply path 71a, a second supply path 71b, and a third supply path 71c. A heater may be provided in the primary air supply path 71 so that the temperature of the primary air supplied to each part can be adjusted.

The first supply path 71a is a path for supplying primary air to the drying step air box 25 provided below the drying grate 21. A first damper 81 is provided in the first supply path 71a, and the amount of primary air supplied to the drying stage air box 25 can be adjusted. Further, the first damper 81 is controlled by the control device 90.

The second supply path 71b is a path for supplying primary air to the combustion stage air box 26 provided below the combustion grate 22. A second damper 82 is provided in the second supply path 71b, and the amount of primary air supplied to the combustion stage air box 26 can be adjusted. Further, the second damper 82 is controlled by the control device 90.

The third supply path 71c is a path for supplying primary air to the post-combustion stage air box 27 provided below the post-combustion grate 23. A third damper 83 is provided in the third supply path 71c, and the amount of primary air supplied to the post-combustion stage air box 27 can be adjusted. Further, the third damper 83 is controlled by the control device 90.

The secondary air supply unit 52 supplies the secondary air to the air gas holding space 16 of the incinerator 10 from the upper part (ceiling part) via the secondary air supply path 72, and the combustion gas is generated by the throttle unit 17. Secondary air is supplied to the portion that changes direction (near the throttle portion 17). Further, the secondary air supply path 72 is provided with a fourth damper 84 controlled by the control device 90, and the amount of secondary air supplied to each part can be adjusted.

The exhaust gas supply unit 53 supplies (recirculates) the exhaust gas discharged from the waste incineration facility 100 into the furnace via the circulating exhaust gas supply path 73. The exhaust gas discharged from the waste incinerator 100 is purified by the filtration type dust collector 60, and a part of the exhaust gas is incinerated by the exhaust gas supply unit 53 from both side surfaces (front side of the paper surface and the back side of the paper surface) of the combustion unit 12. It is supplied to the incinerator 10. The position where the exhaust gas is supplied is not particularly limited. For example, the exhaust gas may be supplied from above (ceiling portion) of the incinerator 10, or may be supplied from only one side surface. By supplying the exhaust gas to the incinerator 10, the oxygen concentration in the incinerator 10 is lowered, and the local excessive rise in the combustion temperature can be suppressed. As a result, the generation of NOx can be suppressed. The circulating exhaust gas supply path 73 is provided with a fifth damper 85 controlled by the control device 90, and the supply amount of the circulating exhaust gas can be adjusted.

As shown in FIGS. 1 and 2, the incinerator 10 is provided with a plurality of sensors for grasping a combustion state and the like. Specifically, an incinerator gas temperature sensor 91, an incinerator outlet gas temperature sensor 92, a CO gas concentration sensor 93, a NOx gas concentration sensor 94, and a visible light camera 95 are provided.

The gas temperature sensor 91 in the incinerator is arranged in the incinerator 10 (for example, downstream of the air gas holding space 16 and upstream of the post-combustion unit 13), detects the gas temperature in the incinerator, and controls the control device 90. Output to. The incinerator outlet gas temperature sensor 92 is arranged near the outlet of the incinerator 10 (for example, downstream of the reburning unit 14 and upstream of the boiler 30), detects the incinerator outlet gas temperature, and sends it to the control device 90. Output. The CO gas concentration sensor 93 is arranged downstream of the dust collector 60, detects the CO gas concentration contained in the exhaust gas (CO gas concentration discharged from the incinerator), and outputs the CO gas concentration sensor 93 to the control device 90. The NOx gas concentration sensor 94 is arranged downstream of the dust collector 60, detects the NOx gas concentration contained in the exhaust gas (NOx gas concentration discharged from the incinerator), and outputs the NOx gas concentration sensor 94 to the control device 90.

In this embodiment, two visible light cameras 95 are provided. Each visible light camera 95 has the same structure. Further, three or more visible light cameras 95 may be provided. A plurality of visible light cameras 95 are provided for the purpose of creating a three-dimensional image. Therefore, the relative positions of the plurality of visible light cameras 95 are stored in advance. The visible light camera 95 may be a device whose main purpose is to continuously capture still images at appropriate intervals, or a device whose main purpose is to capture moving images. .. Since a moving image is a plurality of continuous still images, the function of acquiring a visible image is the same regardless of the device.

Each of the visible light cameras 95 aims to acquire a visible image of the flame combustion start position and a visible image of the waste mainly transported through the dry grate 21. Further, the visible light camera 95 is not an infrared camera for detecting temperature or the like, but a camera for acquiring an image of the appearance (color, brightness, etc.) of waste. Therefore, the visible image acquired by the visible light camera 95 is an image showing the color, brightness, and the like in the furnace as seen from the viewpoint of the visible light camera 95. The viewpoint indicates a position where the visible light camera 95, which is a measuring instrument, is arranged.

Further, in the incinerator 10, it is assumed that drying is completed at the downstream end of the drying unit 11 to generate pyrolysis gas, and flame combustion is started at the upstream end of the combustion unit 12. There is. However, depending on the properties of the supplied waste (for example, the amount of water contained in the waste, the flammability of the waste, the amount of oxygen around the waste), flame combustion may start in the middle of the drying portion 11. Flame combustion may not have started even in the middle of the combustion unit 12. The visible image acquired by the visible light camera 95 does not include waste located at the root of the flame because the flame is an obstacle.

Therefore, in order to image the flame combustion start position, the imaging ranges of the two visible light cameras 95 include images of the boundary between the drying unit 11 and the combustion unit 12 and the vicinity thereof, respectively. Further, in the present embodiment, in order to image the waste of the drying portion 11, the imaging range of the two visible light cameras 95 also includes the surface of the waste of the drying portion 11. More specifically, the imaging range of the two visible light cameras 95 of the present embodiment includes the area from the upstream end of the drying unit 11 to the center of the combustion unit 12 in the waste transport direction. The imaging range of the two visible light cameras 95 may be narrower or wider than that of the present embodiment. Further, the visible light camera 95 may have a configuration in which the imaging range of the image can be changed. In this case, the visible light camera 95 may be able to change the imaging range without stopping the incinerator 10. The visible light camera 95 is arranged at a position higher than the waste for the purpose of appropriately acquiring an image even when the accumulated amount of the waste is large. Therefore, the visible light camera 95 is arranged so as to be inclined downward. The visible light camera 95 may be arranged without being tilted.

As shown in FIG. 3, the direction perpendicular to the waste transport direction and the vertical direction (vertical direction) is referred to as the furnace width direction. The visible light camera 95 acquires an image from the side wall 11a, which is a wall portion formed at the end of the drying portion 11 in the furnace width direction. Specifically, the side wall 11a is provided with two window portions 11b, and the two visible light cameras 95 acquire images through the respective window portions 11b. The window portion 11b is a portion for observing the inside of the furnace. Specifically, a part of the side wall 11a is opened and the opening is closed with transparent (including translucent) heat-resistant glass or the like. It is a part. Two visible light cameras 95 may be arranged in one window portion 11b. Further, in the present embodiment, the visible light cameras 95 are arranged side by side in the transport direction, but they may be arranged side by side in the vertical direction.

In the present embodiment, two visible light cameras 95 are arranged only on one side wall 11a of the left and right side walls 11a, but even if one or a plurality of visible light cameras 95 are arranged on both side walls 11a, respectively. Good. Further, the visible light camera 95 may be arranged on a wall other than the side wall 11a.

<Processing performed by the control device> The control device 90 is composed of a CPU, a RAM, a ROM, and the like, performs various calculations, and controls the entire waste incineration facility 100. Similarly, the image processing device 96 is composed of a CPU, a RAM, a ROM, and the like, and performs a process (image composition process) of creating a three-dimensional visible image based on the visible images acquired by the two visible light cameras 95. Can be done. In the present embodiment, the control device 90 and the image processing device 96 are separate hardware, but one piece of hardware may have the functions of both the control device 90 and the image processing device 96. Hereinafter, the combustion control performed by the control device 90, particularly the control performed by analyzing the three-dimensional visible image, will be described with reference to the flowcharts of FIGS. 4 and 5. 4 and 5 are flowcharts showing the control performed by the control device 90 to stabilize the combustion.

<S101> First, the control device 90 stores a three-dimensional visible image created by the image processing device 96 based on the visible images acquired by the plurality (two) visible light cameras 95 (S101). Since the process of creating a three-dimensional visible image from a plurality of visible images is a known technique, it will be briefly described. Here, in order to distinguish between the two visible light cameras 95, the first and the second may be added and described. The visible image acquired by the first visible light camera shows the color and shape of the surface of the flame and waste as seen from the position of the first visible light camera. The same applies to the second visible light camera. Then, the specific location A on the surface of the flame or the waste is specified where each of the two visible images is displayed. As described above, since the positional relationship between the first visible light camera and the second visible light camera is known, the distance from the first or second visible light camera to the specific location A of the flame or waste based on the trigonometry or the like. Can be calculated. By performing this treatment on other parts of the surface of the waste, the position (three-dimensional coordinates) of the flame or the surface of the waste can be specified. As described above, the visible image acquired by the visible light camera 95 does not include the waste located at the root of the flame. Therefore, the three-dimensional visible image shows the shape of only a part of the waste in the imaging range, not the whole.

<S102> Next, the control device 90 mesh-divides the surface of the waste in the three-dimensional visible image into a plurality of elements (division units), and (1) the thickness of the waste and (2) the surface for each element. The movement speed is calculated and stored in association with the control value (S102). The mesh division is to divide the waste of the three-dimensional visible image into a plurality of regions under predetermined conditions. In the present embodiment, as shown in FIG. 6, the waste is divided into a grid pattern by drawing a plurality of parallel lines in the transport direction and a plurality of parallel lines in the furnace width direction. In the present embodiment, the mesh-divided elements are quadrangular, but may have different shapes. The shapes and areas of the plurality of elements may be the same or different. For example, only the parts considered to be important may be finely divided into meshes. Further, since the waste thickness and the surface moving speed are used to correct the control values of the combustion control as described later, these values are referred to as correction data.

Regarding (1) above, the thickness of the waste is the length along the vertical direction from the grate to the surface of the waste, as shown in FIG. The position of the surface (upper surface) of the grate is stored in advance in the control device 90 or the like. In addition, the position of the surface of the waste can be specified based on the three-dimensional visible image. Therefore, by comparing these two positions (coordinates), the thickness of the waste can be calculated for each element. As described above, the distribution of the thickness of waste for each element at a certain time can be calculated based on one three-dimensional visible image. Since the three-dimensional visible images are sequentially created, the thickness of the waste is calculated in the same manner for the newly created three-dimensional visible images. In this way, the control device 90 calculates the thickness of the waste for each element and stores it in a predetermined storage unit in chronological order.

The significance of calculating the thickness of waste is as follows. That is, the waste accumulated in the drying portion 11 is dried by evaporating the water contained in the waste as the drying operation (feeding operation) of the drying grate 21 is performed, and the mass is reduced and the volume is also reduced. .. That is, the time change of the thickness of the waste indicates the progress of the drying of the waste, and is a kind of index of the progress of the drying operation.

Regarding (2) above, the surface moving speed of the waste is the speed at which the surface of the waste moves in the transport direction, as shown in FIG. In FIG. 6, a thick line is drawn on a relatively thick portion for easy understanding, and a state in which this portion moves is shown. Since the shape of the surface of the waste is shown in the three-dimensional visible image, it is possible to obtain how the surface of the waste is moving based on the three-dimensional visible image created in time series. Therefore, the surface movement speed for each mesh-divided element can be calculated based on the movement distance of a specific portion of the surface of the waste, the time interval at which the three-dimensional visible image is acquired, and the like. As described above, the distribution of the surface moving speed of waste for each element can be calculated. Since the three-dimensional visible images are sequentially created, a new surface movement speed of the waste is calculated using the newly created three-dimensional visible images and the past three-dimensional visible images. In this way, the control device 90 calculates the surface moving speed of the waste and stores it in a predetermined storage unit in chronological order.

The significance of calculating the surface moving speed of waste is as follows. That is, the time change of the moving speed of the waste is the actual speed at which the waste accumulated in the drying portion 11 is sent in the transport direction while reducing the volume by the drying operation (feeding operation) of the drying grate 21. It is an indicator of how waste has been "moved" by the drying operation. Since it is not possible to calculate how the surface other than the surface of the waste moves from the three-dimensional visible image, in the present embodiment, the "surface movement speed of the waste" indicates the "movement speed of the entire waste". Assuming that, the subsequent calculations are performed.

The control value is a value changed to control the combustion state of the incinerator 10, and is, for example, the transfer speed of each grate, the supply amount of the primary combustion gas, the supply amount of the secondary combustion gas, and the like. It is a value for determining. The thickness of the waste, the surface moving speed, and the volumetric flow rate described later are affected by this control value. Therefore, in order to evaluate and control in consideration of the influence of the control value, the control device 90 stores the thickness of the waste and the surface movement speed in association with the control value set in the incinerator 10. Further, when the control value differs depending on the mesh-divided elements (for example, the transfer speed of the grate differs between the element on the dry grate 21 and the element on the combustion grate 22), the control device 90 determines. The waste thickness and surface movement speed are stored in association with the control values corresponding to the corresponding elements.

<S103> Next, the control device 90 calculates the thickness progress information for each element based on the thickness of the waste for each element and the surface moving speed, and stores the information in association with the control value (S103). As shown in FIG. 7, the thickness progress information is information indicating how the thickness changes in time series until the waste located in the element is located in the element. In FIG. 7, the thickness progress information of each element is schematically shown graphically. As shown in this graph, the thickness progress information is information in which "thickness" and "position in the transport direction with the passage of time" are associated with each other. That is, the thickness progress information is information indicating, for example, the thickness of the waste in the element A at the present time when the waste in the element A was present at the upstream position in the past when the element A is focused on. .. The thickness progress information may be information in which the thickness and the time are associated with each other.

The thickness progress information can be calculated as follows, for example. For example, when focusing on a certain element A, the progress of transporting the waste at the position of the element A at the present time (that is, which element was located at which time) is the current state of the element A and the element on the upstream side thereof. It can be calculated based on the past surface movement speed. Further, the thickness of the waste for each element and each time is calculated and stored in step S102. Therefore, the thickness progress information can be calculated by associating the time and the element indicated by the transportation progress of the waste with the thickness of the waste. In this way, the control device 90 calculates the thickness progress information based on the thickness of the waste and the surface moving speed. Since the three-dimensional visible images are sequentially created, new thickness progress information of the waste is calculated by performing the same calculation using the newly created three-dimensional visible images. The control device 90 stores the calculated thickness progress information in a predetermined storage unit in chronological order. The process and the reason for associating the thickness progress information with the control value are the same as in step S102.

The significance of obtaining thickness progress information is as follows. That is, the thickness progress information reduces the volume of the waste accumulated in the drying portion 11 as it accumulates and passes on the grate by the drying operation (feeding operation) of the drying grate 21. However, it shows the process of being sent in the feeding direction, and is an index of how the volume of waste has been reduced by the drying operation.

<S104> Next, the control device 90 calculates the volume flow rate progress information for each element based on the surface movement speed and the thickness progress information of the waste for each element, and stores it in association with the control value (S104). As shown in FIG. 8, the volumetric flow rate progress information is information indicating how the volumetric flow rate has changed in time series until the waste located in the element is located in the element. In FIG. 8, the volumetric flow rate progress information of each element is schematically shown graphically. As shown in this graph, the volume flow rate progress information is information in which the “volume flow rate” and the “transportation direction position with the passage of time” are associated with each other. That is, the volumetric flow rate progress information is information indicating what kind of volumetric flow rate the waste in the element A at the present time had when it was present at the upstream position in the past, for example, when focusing on the element A. Is. The volume flow rate progress information may be information indicating the correspondence between the volume flow rate and the time.

Volumetric flow rate is the volume of waste that moves per unit time. Therefore, the volumetric flow rate can be calculated by multiplying the "waste thickness", "waste surface moving speed", and "furnace width length", respectively. Further, the furnace width length when calculating the volume flow rate for each element is the furnace width length of each element. Therefore, the volume flow rate progress information is the value obtained by multiplying the "thickness of waste indicated by the thickness progress information" and the "surface movement speed of waste" by combining the elements (position) and the time, and "the furnace width of each element". It can be calculated by multiplying by "length". In this way, the control device 90 calculates the volume flow rate progress information for each element and stores it in a predetermined storage unit. Since the three-dimensional visible images are sequentially created, new volume flow rate progress information of the waste is calculated by performing the same calculation using the newly created three-dimensional visible images. The control device 90 stores the calculated volumetric flow rate progress information in a predetermined storage unit in time series in association with the control value. The process and the reason for associating the volume flow rate progress information with the control value are the same as in step S102. Moreover, since the furnace width and length are constant, the volumetric flow rate progress information is a function of only the waste thickness and the surface moving speed. In other words, the volumetric flow rate progress information is conceptual information that includes not only the thickness of waste but also the moving speed.

If the furnace width length of each grate is constant and the furnace width length of each element is constant, the process of multiplying the furnace width length may be omitted. This is because what is required for combustion control is not a specific value of the volumetric flow rate, but a variation mode thereof. In other words, the vertical axis of the graph in the upper figure of FIG. 8 is not limited to a specific volume flow rate, and may be a value proportional (correlated) to the volume flow rate.

The significance of acquiring volumetric flow rate progress information is as follows. That is, the waste accumulated in the drying portion 11 is compressed by the evaporation of water as the drying operation (feeding operation) of the drying grate 21 is performed, and the mass and volume are reduced. That is, the volumetric flow rate progress information indicates the progress of the waste drying, and is a direct index of the degree of progress of the drying operation. Here, as the drying of the waste progresses and the moisture from the waste evaporates (dry state), the amount of evaporation of the moisture decreases and the internal temperature of the waste layer rises, so that the waste heats up. It shifts to the state where decomposition gas is generated (thermal decomposition state). Further, since combustion can be started when the pyrolysis state is reached, the state after the transition to the pyrolysis state is referred to as a "combustion startable state". Further, by shifting to the state where combustion can be started, the degree of change in the volume of waste becomes smaller. Therefore, the volumetric flow rate progress information is the most suitable index for evaluating the degree of the state in which combustion can be started.

<S105> Next, the control device 90 determines whether or not the current state is capable of starting combustion for each element based on the volume flow rate progress information for each element, and stores the determination result (S105). As described above, the degree of change in the volumetric flow rate of waste is greatly reduced at the timing of transition to the combustible startable state. Therefore, it is possible to determine whether or not the element is in the combustion start state based on the volume flow rate progress information for each element. However, since the degree of change in the volumetric flow rate differs depending on the control value of the incinerator 10, it is preferable to perform the determination using a condition (for example, a threshold value) according to the control value. Even if the waste is ready for combustion, it does not necessarily mean that combustion has actually started. This is because even if the waste is in a state where combustion can be started, combustion does not occur depending on the amount of oxygen around the waste and the temperature conditions.

Here, as described above, the visible image acquired by the visible light camera 95 does not include the waste located at the root of the flame. Therefore, it is not possible to calculate the volumetric flow rate progress information for the waste at the position where the flame is generated and the waste in the vicinity thereof. Here, when the time from when the waste is in the combustible startable state to when the flame is generated is relatively long, the element in which the combustion can be started can be identified based on the volume flow rate progress information. However, if a flame is generated at the same time that the waste is in a state where combustion can be started , the fact that the degree of change in the volumetric flow rate has changed significantly cannot be detected. Therefore, the state where combustion can be started is possible based only on the volume flow rate progress information. It is difficult to identify the factors.

<S106> Therefore, in order to compensate for the omission of the volume flow rate progress information, the control device 90 determines and stores each element whether or not a flame is generated based on the three-dimensional visible image (S106). The control device 90 identifies the position of the flame, for example, based on the difference in color and brightness between the flame and the waste. Then, for each element of the waste, it is determined whether or not a flame is generated from the waste, and the determination result is stored. It is possible to detect the presence or absence of a flame even by using a visible image acquired by one visible light camera 95. However, since it is not possible to accurately determine the position where the flame is generated, it is not possible to determine whether or not the flame is generated for each element. Therefore, it is necessary to make a determination based on a three-dimensional visible image as in the present embodiment.

<S107> Next, the control device 90 identifies and stores the position where the flame starts (flame generation start position) and the time based on the determination result for each element of whether or not the flame is generated. (S107). The position where the flame starts to be generated is the position of the flame on the most upstream side in the transport direction among the flames included in the three-dimensional visible image (more specifically, it exists on the surface of the waste of the flames). The position of the part). In other words, among the elements determined to generate the flame in step S106, the element on the most upstream side in the transport direction is specified. As a result, the flame generation start position at a certain time is specified. By performing this process using a three-dimensional visible image created in chronological order, the position and time at which the flame starts to occur can be specified.

<S108> Next, the control device 90 specifies the combustion start evaluation position based on the determination result for each element as to whether or not the combustion start is possible state and the determination result of the flame generation start position (S108). .. The combustion start evaluation position is an index of the position where combustion has started in the incinerator 10 as a whole, and is a position for evaluating combustion. In other words, the combustion start evaluation position is a position where "where combustion started" is represented by the entire incinerator 10 in the waste incineration process. When incinerating waste, which is a mixture of substances with various properties, the time required for each substance to reach the "combustion startable state" varies, so the "combustion startable state" and "flame" The "position where the generation starts" also varies, and the positions in the transport direction do not always match. For example, the distribution shown in FIG. 9 may occur. Note that FIG. 9 is a schematic view of the transport unit 20 viewed in the vertical direction, and each of the squares shown in FIG. 9 is a mesh-divided element. As described above, there are some elements in which the flame is not generated (combustion has not started) even though the combustion can be started. As shown in FIG. 9, since the position where the combustion can be started and the combustion start position based on the presence or absence of the flame vary, the judgment result for each element is comprehensively evaluated to evaluate the combustion start of the incinerator 10 as a whole. Identify the location. In particular, for elements for which the flame is an obstacle and sufficient volume flow rate progress information of the waste product is not obtained, the combustion start evaluation position of the incinerator 10 as a whole is specified by referring to the combustion start position based on the presence or absence of the flame. ..

In addition, this method uses "volume flow rate progress information" that shows the same behavior even when the properties and mixing ratio of substances with various properties contained in each "lump" of waste change. Since the combustion startable state is determined, the combustion startable state can be determined with high reliability. The combustion start evaluation position indicates a position in the transport direction, but can also be treated as, for example, a straight line or a curved line extending in the furnace width direction.

The combustion start evaluation position may exist in the combustion unit 12 instead of the drying unit 11. Even in that case, in order to specify the combustion start evaluation position, it is preferable that the above-mentioned treatments of steps S101 to S108 are performed not only on the drying unit 11 but also on the waste in the combustion unit 12.

<S109> Next, the control device 90 determines whether or not the combustion start evaluation position has moved to the upstream side based on the time change of the combustion start evaluation position (S109). This determination is made by comparing the combustion start evaluation position calculated in the past with the current combustion start evaluation position. For example, when the amount of water contained in the waste supplied to the incinerator 10 is reduced or flammable waste is supplied, the waste is dried (and thermally decomposed by drying) in the drying unit 11. The time actually required (actual drying time) is shortened in order to make it (the same applies hereinafter). Therefore, the actual drying time is shorter than the estimated drying time of the waste (difference occurs). In this case, as shown in FIG. 10, since the drying is completed in the middle part of the drying part 11, flame combustion occurs in the middle part of the drying part 11 (the combustion start position moves to the upstream side).

If this state is left unattended, flame combustion will proceed in the drying unit 11, so that the residence time required for flame combustion in the combustion unit 12 will be shortened, and the flame combustion will occur in the middle of the combustion unit 12. Combustion gradually starts after the stage of. As a result, the positions of drying, combustion, and post-combustion on the grate gradually move to the upstream side as a whole, and the burnout position (end position of flame combustion) deviates from the appropriate range. It becomes impossible to maintain stable combustion.

<S110> In order to prevent this, the control device 90 basically determines that the combustion start evaluation position has moved to the upstream side (in the case of Yes in S109), the waste of the dry grate 21. The transport speed (hereinafter, simply the transport speed) is increased (S110). As described above, in order to increase the transport speed, the operating speed of the movable grate of the dry grate 21 is increased, or in lieu of or in addition, the downtime of the movable grate of the dry grate 21 is increased. To shorten. This makes it possible to prevent the positions of drying, burning, and post-combustion on the grate from moving to the upstream side. Therefore, since the burnout position can be contained in an appropriate range, stable combustion can be maintained. The operating speed or stop time of the movable grate is an example of a control value in controlling the transport speed.

However, based on the fact that the information on the combustion start evaluation position used for the determination when the transport speed of the drying grate 21 is increased is the information on the waste that has already been dried (past information), it is actually dried. Further stable combustion can be maintained by correcting the degree of increase in the transport speed based on the above-mentioned correction data which is information on the properties of the waste in the part 11. In the process of step S110 and other processes, when performing correction based on the correction data, at least one of the time change of the thickness of the waste and the time change of the moving speed of the surface of the waste is used. Make corrections.

Specifically, when the decrease in the thickness of waste is accelerating (that is, when the amount of decrease in thickness per unit time (positive) is large), the actual drying time is even shorter than the assumed drying time. Therefore, it may be preferable to further increase the transport speed. Further, since the moving speed of the surface of the waste is information on the current transport speed of the waste, it is preferable to change the transport speed of the dry grate 21 in consideration of these values.

The drying and combustion generated in the incinerator 10 greatly differ depending on the shape and structure of the incinerator 10 and the waste to be charged. In addition, the target state differs greatly depending on the required processing amount, the durability of the incinerator 10, the laws and regulations regarding exhaust gas, and the like. Therefore, even if the combustion start evaluation position is moved to the upstream side, it is conceivable that the control for increasing the transport speed is not performed. Similarly, with respect to the correction of the transport speed based on the correction data, the correction opposite to the above may be performed. In addition, the control device 90 is not limited to the correction data as well as whether or not the combustion start evaluation position is moved to the upstream side and the degree of the necessity and degree of increase in the transport speed of the dry grate 21. It is preferable to determine based on the detection data (for example, the detection data from the incinerator gas temperature sensor 91 to the NOx gas concentration sensor 94 and the like).

<S111> When the control device 90 determines that the combustion start evaluation position has not moved to the upstream side (No in S109), the combustion start evaluation position is on the downstream side based on the time change of the combustion start evaluation position. It is determined whether or not the vehicle has moved to (S111). This determination is made by comparing the combustion start evaluation position calculated in the past with the current combustion start evaluation position in the same manner as described above.

For example, when the amount of water contained in the waste supplied to the incinerator 10 increases or the waste that is hard to burn is supplied, the actual drying time for drying the waste in the drying unit 11 is increased. become longer. Therefore, the actual drying time is longer than the assumed drying time of the waste that is assumed in advance (difference occurs). In this case, as shown in FIG. 11, since the drying is not completed even at the downstream end of the drying unit 11, flame combustion starts in the middle of the combustion unit 12 (the combustion start position moves to the downstream side). ) Will be.

If this state is left unattended, the residence time required for flame combustion is not secured in the combustion unit 12, so that the flame combustion that should be completed in the combustion unit 12 shifts to the post-combustion unit 13, and later. Post-combustion starts in the middle of the combustion unit 13. As a result, the respective positions of drying, combustion, and post-combustion on the grate gradually move to the downstream side as a whole, and the combustion start position and the burnout position deviate from the appropriate range. It becomes impossible to maintain stable combustion.

<S112> In order to prevent this, the control device 90 basically determines the transport speed of the dry grate 21 when it is determined that the combustion start evaluation position is moving to the downstream side (Yes in S111). Decelerate (S112). As described above, in order to reduce the transport speed, the operating speed of the movable grate of the dry grate 21 is reduced, or in place of or in addition, the stop time of the movable grate of the dry grate 21 is lengthened. To do. This makes it possible to prevent the positions of drying, burning, and post-combustion on the grate from moving to the downstream side. Therefore, the combustion start position and the burnout position can be kept in an appropriate range, so that stable combustion can be maintained.

Further, even when the transport speed is reduced, it is preferable to perform the correction based on the correction data for the same reason as described above. Specifically, when the decrease in the thickness of the waste is accelerating, the actual drying time tends to be shorter than the assumed drying time, so it may be preferable to reduce the degree of deceleration of the transport speed. Similarly, when the moving speed of the surface of the waste is accelerating, the actual drying time tends to be shorter than the assumed drying time. Therefore, it may be preferable to reduce the degree of deceleration of the transport speed. .. For the reason explained in the correction at the time of increasing the transport speed, the correction of the transport speed based on the correction data may be performed in the opposite direction to the above depending on the conditions such as the environment. Further, also in the control at the time of deceleration of the transport speed, it is preferable to determine the control value based on still another detection data.

Further, assuming that there is a difference between the actual drying time and the estimated drying time of the waste that is assumed in advance, changing the transport speed of the dry grate 21 actually supplies the dry grate 21 to the combustion grate 22. It means that the properties of the waste that have been made are already different from the conventional assumptions. As a result, if the transport speeds of the combustion grate 22 and the post-combustion grate 23 are the same as those in the conventional state, stable combustion cannot be maintained because the time required for combustion and post-combustion has already changed. ..

<S113> In order to prevent this, when the transfer speed of the dry grate 21 is changed (Yes in S109 or S111), the control device 90 is the waste that is the cause of the change in the transfer speed of the dry grate 21. The transport speeds of the combustion grate 22 and the post-combustion grate 23 are changed according to the state of change in the properties of the above (S113). The control device 90 determines whether or not the transfer speed of the combustion grate 22 and the post-combustion grate 23 needs to be changed and the amount to be changed, not only the amount of change in the transfer speed of the dry grate 21, but also other detection data. It is preferable to make a decision based on.

Further, even when the transport speeds of the combustion grate 22 and the post-combustion grate 23 are changed, it is preferable to perform the correction based on the correction data for the same reason as described above. Basically, like the dry grate 21, it is preferable to change the transport speed of the combustion grate 22 and the post-combustion grate 23, but the waste existing in the dry grate 21 is transferred to the post-combustion grate 23. There is a correlation between the time lag until arrival (in other words, the difference in the properties of waste in each part), the drying time in the drying part 11, the burning time in the burning part 12, and the post-burning time in the post-burning part 13. It may be preferable to perform control different from the above for reasons such as being unable to say.

<S114> Next, the control device 90 uses at least one of the first damper 81 to the fifth damper 85 according to the state of the change in the properties of the waste that is the cause of the change in the transport speed of the dry grate 21. By adjusting, the supply amounts of the primary combustion gas and the secondary combustion gas are adjusted (S114). That is, the opening degree of the first damper 81 to the fifth damper 85 is an example of the control value. Conventionally, for example, the supply amounts of the primary combustion gas and the secondary combustion gas are adjusted by using the detection data of the NOx gas concentration sensor 94 from the gas temperature sensor 91 in the incinerator.

On the other hand, in the present embodiment, in addition to other detection data, the primary combustion gas and the primary combustion gas are based on the moving direction of the combustion start evaluation position (whether it is moving to the upstream side or the downstream side). Adjust the supply amount of secondary combustion gas. Here, when the combustion start evaluation position is moved to the upstream side and the transport speed of each grate is increased, it is generally generated per hour of pyrolysis gas, although it is related to the properties of waste. As the amount increases, the amount of primary combustion gas (including unburned gas such as CO) generated by the primary combustion increases per hour. Therefore, it is necessary to increase the supply amount of the primary combustion gas and the secondary combustion gas. On the other hand, when the combustion start evaluation position is moved to the downstream side and the transport speed of each grate is slowed down, the amount of pyrolysis gas generated per hour is generally related to the properties of waste. And the amount of primary combustion gas generated per hour due to the primary combustion is reduced. Therefore, it is necessary to reduce the supply amount of the primary combustion gas and the secondary combustion gas.

Further, even when the supply amounts of the primary combustion gas and the secondary combustion gas are changed, it is preferable to perform the correction based on the correction data for the same reason as described above. For example, primary air, which is one of the primary combustion gases, is used not only for drying in the drying unit 11 but also for combustion in the combustion unit 12, so if it is preferable to shorten the actual drying time, the primary air It may be preferable to increase the supply of. However, since the primary air is also used for combustion in the combustion unit 12, such correction may not be performed.

Further, since the properties of the waste may change at all times, the control device 90 performs the processing of step S101 and subsequent steps again after the case of No in step S112 and the processing of step S114. As a result, even if the properties of the waste change, it can be corrected so that the progress of drying and burning of the waste becomes appropriate, so that the combustion start position and the burnout position are set within an appropriate range. It can be stored and stable combustion can be maintained.

As shown above, the combustion condition evaluation method of the present embodiment is divided into a drying unit 11, a combustion unit 12, and a post-combustion unit 13, and operates intermittently in a state where waste is accumulated. This is done for the incinerator 10 provided with a grate for transporting the waste. This combustion state evaluation method includes a production step, a division step, a flame determination step, a first calculation step, a second calculation step, a third calculation step, a state determination step, and an evaluation step. In the creation step, a plurality of visible light cameras 95 are used to observe the flame and at least the waste deposited on the dry portion 11, and a plurality of visible images having different viewpoints are acquired, and based on the plurality of visible images, the plurality of visible images are obtained. Create a 3D visible image. In the dividing step, the waste of the three-dimensional visible image is mesh-divided into a plurality of elements. In the flame determination step, it is determined for each element whether or not a flame is generated from the waste based on the three-dimensional visible image. In the first calculation step, the thickness of the waste and the surface movement speed of the waste are calculated for each element based on the three-dimensional visible image. In the second calculation step, based on the calculation result of the first calculation step, the element includes thickness progress information indicating how the thickness of the waste located in the element changes in time series until it is located in the element. Calculated for each. In the third calculation step, based on the calculation results of the first calculation step and the second calculation step, it is shown how the volume flow rate changes in time series until the waste located in the element is located in the element. Volumetric flow rate progress information is calculated for each element. In the state determination step, the volume flow rate progress information is analyzed, and it is determined for each element whether or not the waste is in a combustion startable state indicating a state in which the waste has shifted from the dry state to the thermal decomposition state. In the evaluation step, the combustion start evaluation position, which is an index of the position where combustion has started in the incinerator 10 as a whole and is a position for evaluating combustion, is specified based on the judgment results of the flame determination step and the state determination step.

As a result, the combustion start position is evaluated based on both the position where combustion can be started and the position where combustion is determined to have started based on the flame, so that the state of waste and combustion can be more accurately determined. Can be evaluated. In particular, since the combustion start evaluation position is specified based on how the volumetric flow rate of the waste has changed over time, the combustion start evaluation position can be specified with high reliability.

Further, in the combustion condition evaluation method of the present embodiment, in the flame determination step, among the elements in which the flame is generated from the waste, the position of the element located on the most upstream side in the waste transport direction is set as the flame generation start position. Identify as. In the evaluation step, the combustion start evaluation position is specified based on the judgment result of the flame generation start position and the state determination step.

As a result, the combustion start evaluation position can be specified by effectively utilizing the determination result of whether or not a flame has occurred.

Further, in the combustion control method of the present embodiment, when it is specified that the combustion start evaluation position is moved to the upstream side in the transport direction, the dry grate 21 controls to increase the transport speed of the waste. .. When it is specified that the combustion start evaluation position is moved to the downstream side in the transport direction, the dry grate 21 controls to reduce the transport speed of the waste.

As a result, the difference between the assumed drying time and the actual drying time can be reduced, so that the progress of drying and burning of the waste can be made more appropriate. As a result, the burnout position can be kept within an appropriate range, and stable combustion can be maintained.

Further, in the combustion control method of the present embodiment, the waste transport speed by the dry grate 21 is based on at least one of the waste thickness and the surface movement speed of the waste calculated in the first calculation step. The control value for shifting the speed is corrected.

As a result, the control value can be corrected by using the information on the properties of the waste actually in the drying unit 11 in addition to the combustion start evaluation position, so that the waste actually in the drying unit 11 can be used as compared with the case where the correction is not performed. A consistent and stable combustion can be maintained.

Further, in the combustion control method of the present embodiment, the transport speed of the dry grate 21 is changed, and the combustion fire is changed according to the state of the change in the properties of the waste that is the cause of the change in the transport speed of the dry grate 21. The transport speed of the grate of the grate 22 and the post-combustion grate 23 is changed.

Thereby, by changing not only the transport speed of the dry grate 21, but also the transport speed of the combustion grate 22 and the post-combustion grate 23, it is possible to correct the overall fluctuation of the combustion state.

Further, in the combustion control method of the present embodiment, the drying unit 11, the combustion unit 12, and the post-combustion unit are based on whether the combustion start evaluation position is moved to the upstream side in the transport direction or the downstream side in the transport direction. The amount of primary combustion gas supplied to at least one of 13 is adjusted.

As a result, it is possible to correct the excess or deficiency of the primary combustion gas caused by changing the transport speed of the waste, so that drying, combustion, and post-combustion can be performed more appropriately.

Further, in the combustion control method of the present embodiment, in the incinerator 10, the primary combustion performed in the drying unit 11, the combustion unit 12, and the post-combustion unit 13 and the primary combustion gas including the unburned gas generated in the primary combustion. Secondary combustion, which burns, is performed. The supply amount of the secondary combustion gas is adjusted based on whether the combustion start evaluation position is moved to the upstream side in the transport direction or the downstream side in the transport direction.

As a result, the progress of primary combustion (that is, the amount of primary combustion gas generated, etc.) can be estimated based on the moving direction of the combustion start evaluation position, and the supply amount of secondary combustion gas is adjusted accordingly. As a result, the unburned gas contained in the primary combustion gas can be sufficiently burned in the secondary combustion.

Although the preferred embodiment of the present invention has been described above, the above configuration can be changed as follows, for example.

In the above embodiment, the process of creating a three-dimensional visible image of the entire transport direction (from the upstream end to the downstream end) of the drying portion 11 has been described. Instead, the control device 90 displays a three-dimensional visible image of a part of the drying unit 11 in the transport direction (for example, a portion excluding the upstream end and its vicinity, or a portion downstream from the center of the transport direction). It may be a configuration to be created.

In the above embodiment, the transport speed from the dry grate 21 to the post-combustion grate 23 (particularly the dry grate 21) and the supply of the primary combustion gas and the secondary combustion gas are based on the moving direction of the flame combustion evaluation position. Although the process of changing the amount and is performed, the process of changing these values may be performed by using the moving speed in addition to the moving direction of the combustion start evaluation position.

The flowchart shown in the above embodiment is an example, and some processes may be omitted, the contents of some processes may be changed, or new processes may be added. For example, in the above embodiment, the correction is performed based on the correction data in all of steps S110, S112, S113, and S114, but the correction based on the correction data may be omitted for at least one of these processes. Further, in step S111, correction based on the correction data may be performed on only one of the combustion grate 22 and the post-combustion grate 23, not both.

In the above embodiment, as the detection data used in the combustion control, the detection data of the incinerator gas temperature sensor 91, the incinerator outlet gas temperature sensor 92, the CO gas concentration sensor 93, and the NOx gas concentration sensor 94 have been described. , Combustion control may be performed by omitting at least one detection data, or combustion control may be performed by adding detection data other than the above. As another detection data, for example, the amount of boiler evaporation associated with the recovery of heat from the exhaust gas, or the amount of water for water spray cooling when cooling by water spray can be used.

10 Incinerator 11 Drying part 12 Combustion part 13 Post-combustion part 21 Dry grate 22 Combustion grate 23 Post-combustion grate 90 Control device 95 Visible light camera 96 Image processing device

Claims (7)

For incinerators equipped with a grate that is divided into a drying section, a combustion section, and a post-combustion section and that transports the waste by operating intermittently in a state where the waste is accumulated.
Using a plurality of visible light cameras, the flame and at least the waste deposited on the dry portion are observed, a plurality of visible images having different viewpoints are acquired, and a three-dimensional visible image is obtained based on the plurality of visible images. And the creation process to create
A division step of mesh-dividing the waste of the three-dimensional visible image into a plurality of elements, and
Based on the three-dimensional visible image, a flame determination step of determining whether or not a flame is generated from the waste for each element, and a flame determination step.
A first calculation step of calculating the thickness of the waste and the surface moving speed of the waste for each element based on the three-dimensional visible image, and
Based on the calculation result of the first calculation step, thickness progress information indicating how the thickness of the waste located in the element changes in time series until it is located in the element is provided for each element. The second calculation process to calculate and
Based on the calculation results of the first calculation step and the second calculation step, the volume flow rate showing how the volume flow rate changed in time series until the waste located in the element was located in the element. The third calculation step of calculating the progress information for each of the elements, and
A state determination step of analyzing the volumetric flow rate progress information and determining for each element whether or not the waste is in a combustion startable state indicating a state in which the waste has shifted from a dry state to a thermal decomposition state.
Based on the determination results of the flame determination step and the state determination step, an evaluation step of specifying a combustion start evaluation position, which is an index of a position where combustion has started in the incinerator as a whole and is a position for evaluating combustion, and an evaluation step.
A combustion condition evaluation method characterized by performing a process including. The combustion condition evaluation method according to claim 1.
In the flame determination step, among the elements in which the flame is generated from the waste, the position of the element located on the most upstream side in the transport direction of the waste is specified as the flame generation start position.
The evaluation step is a combustion state evaluation method characterized in that a combustion start evaluation position is specified based on a flame generation start position and a determination result of the state determination step. A combustion control method for controlling combustion in the incinerator by using the combustion condition evaluation method according to claim 2.
When it is specified that the combustion start evaluation position is moving to the upstream side in the transport direction, control is performed to increase the transport speed of the waste by the grate of the drying portion.
When it is specified that the combustion start evaluation position is moved to the downstream side in the transport direction, the combustion control is characterized in that the control is performed to reduce the transport speed of the waste by the grate of the drying portion. Method. The combustion control method according to claim 3.
In order to shift the transport speed of the waste by the grate of the drying portion based on at least one of the thickness of the waste and the surface movement speed of the waste calculated in the first calculation step. A combustion control method characterized by correcting the control value of. The combustion control method according to claim 3 or 4.
The fire of the combustion part is changed according to the state of change in the properties of the waste that is the cause of the change of the transport speed of the grate of the drying portion and the change of the transport speed of the grate of the drying portion. A combustion control method comprising changing the transport speed of the lattice and the grate of the post-combustion unit. The combustion control method according to any one of claims 3 to 5.
Primary combustion supplied to at least one of the drying section, the combustion section, and the post-combustion section based on whether the combustion start evaluation position is moved to the upstream side in the transport direction or the downstream side in the transport direction. A combustion control method characterized by adjusting the supply amount of gas for use. The combustion control method according to any one of claims 3 to 6.
In the incinerator, primary combustion performed in the drying unit, the combustion unit, and the post-combustion unit, and secondary combustion for burning the primary combustion gas including the unburned gas generated in the primary combustion are performed. ,
A combustion control method characterized in that the supply amount of a secondary combustion gas is adjusted based on whether the combustion start evaluation position is moved to the upstream side in the transport direction or the downstream side in the transport direction.

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