JP2019219108A - In-furnace situation determination method and evaporation amount control method - Google Patents

Abstract

To provide a method for acquiring an exact index of calorie which is currently generated in a combustion chamber.SOLUTION: An in-furnace situation determination method includes an image acquisition process, a three-dimensional image creation process, a flame cross-section area calculation process and a flame flow velocity calculation process. In the image acquisition process, images of flames arriving at a secondary combustion zone 14 from a primary combustion zone 10 are acquired by using a plurality of imaging devices 96 which are different in viewpoints. In the three-dimensional image creation process, a three-dimensional image including the flames in the secondary combustion zone 14 is created by applying image synthesizing processing to the plurality of images different in viewpoints which are acquired in the image acquisition process. In the flame cross-section area calculation process, a temporal change of a flame cross-section area of the secondary combustion zone 14 which is made by cutting at a prescribed virtual plane intersecting with a flow passage of a combustion gas is calculated by analyzing the three-dimensional image. In the flame flow velocity calculation process, a temporal change of a flame flow velocity in a direction along the flow passage of the combustion gas is calculated by analyzing the three-dimensional image.SELECTED DRAWING: Figure 1

Description

  The present invention mainly relates to an in-furnace condition determination method for obtaining an index of the amount of heat currently generated in a combustion chamber.

  BACKGROUND ART Conventionally, there is known a waste incineration facility including a combustion chamber for performing primary combustion and secondary combustion for burning primary combustion gas including unburned gas generated in primary combustion. Patent Literatures 1 to 4 disclose obtaining an index of a situation in a furnace, particularly an amount of heat generated in a combustion chamber, based on various data.

  Patent Literature 1 discloses that in a facility including a boiler that generates steam using heat generated by the combustion of waste, a change in the boiler evaporation is predicted based on the boiler evaporation obtained in time series. ing. Note that the boiler evaporation amount increases as the amount of heat generated in the combustion chamber increases.

  Patent Document 2 discloses that a calorific value of waste is obtained from a component concentration of exhaust gas generated by burning the waste, and a boiler evaporation is estimated based on the calorific value of the waste.

  Patent Document 3 discloses that an image of a flame in a combustion chamber is captured by a single camera, and the brightness, color, flame shape, and the like of the flame are quantified based on the captured image of the flame. ing. The flame generated in the combustion chamber is related to the amount of heat generated in the combustion chamber.

  Patent Literature 4 discloses that an image of a flame in a combustion chamber is captured by one camera, and the height of the flame and the area of the flame in a predetermined range are calculated based on the captured image of the flame. I have.

JP 2001-289401 A JP-A-2017-96517 JP-A-2006-186382 JP-A-7-158835

  However, while the amount of boiler evaporation used in Patent Document 1 has a relatively high correlation with the amount of heat generated in the combustion chamber, it takes time for the amount of heat generated in the combustion chamber to contribute to the evaporation of the boiler. The boiler evaporation is correlated not with the amount of heat currently generated in the combustion chamber, but with the amount of heat generated before that. Therefore, it may not be appropriate to use the boiler evaporation as an index of the amount of heat currently generated in the combustion chamber.

  Further, according to the method of Patent Document 2, when the property of the input waste material changes and the relationship between the component concentration of the exhaust gas and the calorific value changes, an index of the calorific value currently generated in the combustion chamber is appropriately obtained. I can't.

  Further, in the methods of Patent Documents 3 and 4, since the shape of the flame cannot be appropriately acquired, there is a possibility that the index of the amount of heat currently generated in the combustion chamber cannot be appropriately obtained. Specifically, in this method, it is impossible to distinguish between a state where the flame is locally high in the depth direction of the image and a state where the flame is high in the entire depth direction.

  The present invention has been made in view of the above circumstances, and a main object of the present invention is to provide a method for obtaining an accurate index of the amount of heat currently generated in a combustion chamber.

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

  As described above, according to the aspects of the present invention, the following in-furnace state determination method is provided. In other words, this in-furnace situation determination method uses a primary combustion zone for performing primary combustion using a primary combustion gas, and a primary combustion gas containing an unburned gas generated in the primary combustion using a secondary combustion gas. This is performed for a waste incineration plant including a combustion chamber having a secondary combustion zone for performing secondary combustion. In this in-furnace situation determination method, a process including an image acquisition step, a three-dimensional image creation step, a flame cross-sectional area calculation step, and a flame velocity calculation step is performed. In the image acquisition step, images of the flames that have reached the secondary combustion zone from the primary combustion zone are acquired using a plurality of imaging devices having different viewpoints. In the three-dimensional image creation step, a three-dimensional image including the flame of the secondary combustion zone is created by performing image synthesis processing on a plurality of images from different viewpoints acquired in the image acquisition step. In the flame cross-sectional area calculation step, the three-dimensional image is analyzed to cut off the flame of the secondary combustion zone cut by a predetermined virtual plane that intersects the flow path of the combustion gas generated in the primary combustion or the secondary combustion. Calculate the time change of the area. In the flame velocity calculation step, the time change of the flame velocity in the direction along the flow path of the combustion gas generated in the primary combustion or the secondary combustion is calculated by analyzing the three-dimensional image.

  Thus, by using the flame cross-sectional area and the flame velocity of the secondary combustion zone, an accurate index of the amount of heat currently generated in the combustion chamber can be obtained.

  According to the present invention, an accurate index of the amount of heat currently generated in the combustion chamber can be obtained.

The schematic block diagram of the waste incineration equipment which performs the method of this invention. Functional block diagram of an incinerator. The three-dimensional schematic diagram of the incinerator which shows the attachment position of an imaging device, and a virtual plane. 9 is a flowchart showing control performed by the control device to stabilize the boiler evaporation amount.

  <Overall Configuration of Waste Incineration Facility> First, a waste incineration facility 100 of the present embodiment will be described with reference to FIG. FIG. 1 is a schematic configuration diagram of a waste incineration facility 100 according to one embodiment of the present invention. In the following description, the terms “upstream” and “downstream” simply mean upstream and downstream in the direction in which waste, combustion gas, combustion gas, exhaust gas, and the like flow.

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

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

  The steam turbine power generation equipment 35 is configured to include a turbine and a power generation device (not shown). The turbine is driven to rotate by steam supplied from the water pipe 31 and the superheater pipe 32. The power generation device generates power using the rotational driving force of the turbine.

  <Configuration of Incinerator> The incinerator 1 includes a dust supply device 40 for supplying waste into the incinerator. The dust feeding device 40 includes a waste input hopper 41 and a dust feeding device main body 42. The waste input hopper 41 is a portion into which waste is input from outside the furnace. The dust feeding 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 put in the waste input hopper 41 to the downstream side. The movement speed, the number of movements per unit time, the movement amount (stroke), and the position of the stroke end (movement range) of the dust feeding device main body 42 are controlled by the control device 90 shown in FIG. The dust feeding device may be of a type that moves at a certain angle with respect to the horizontal direction.

  The waste supplied into the furnace by the dust supply device 40 is supplied to the combustion chamber 2. The combustion chamber 2 includes a primary combustion zone 10 and a secondary combustion zone 14. The primary combustion zone 10 is a space for primary combustion. The primary combustion refers to reacting the input waste with a gas for primary combustion to burn the waste. The primary combustion gas is a gas containing oxygen supplied for the primary combustion. 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 a gas not used for combustion or the like (that is, excluding circulating exhaust gas). Therefore, the primary air includes a gas obtained by heating air taken in from the outside. In addition, the primary combustion generates a primary gas (primary combustion) containing unburned gas such as CO.

  The primary combustion zone 10 includes a drying section 11, a combustion section 12, and a post-combustion section 13. The waste 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 includes 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. I have. Therefore, the transport section 20 is composed of a plurality of stages of grate. Each grate is provided on the bottom surface of each part, and waste is placed thereon. 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 intermittently moves forward and backward to transport waste to the downstream side. At the same time, the waste can be stirred. The operation of the grate is controlled by the control device 90. The grate is provided with a gap large enough to allow gas to pass through.

  The drying section 11 is a section that dries the waste supplied to the incinerator 1. The waste in the drying unit 11 is dried by the primary air supplied from below the drying grate 21 and the radiant heat of combustion in the adjacent combustion unit 12. At this time, pyrolysis gas is generated from the waste in the drying unit 11 due to pyrolysis. The waste from the drying unit 11 is transported toward the combustion unit 12 by the drying grate 21.

  The combustion section 12 is a section for mainly burning the waste dried in the drying section 11. In the combustion section 12, the waste mainly causes flame combustion, and a flame is generated. The waste in the combustion unit 12, the ash generated by the combustion, and the unburned material that has not been completely burned are conveyed toward the post-combustion unit 13 by the combustion grate 22. Further, the primary combustion gas and the flame generated in the combustion section 12 flow toward the post-combustion section 13 through the throttle section 17. 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 unit 13 is a unit that burns waste (unburned material) that has not been completely burned in the combustion unit 12. In the post-combustion unit 13, the radiant heat of the primary combustion gas and the primary air promote the combustion of unburned substances that have not been completely burned in the combustion unit 12. As a result, most of the unburned matter becomes ash, and the unburned matter decreases. The ash generated in the post-combustion unit 13 is transported toward the chute 24 by a post-combustion grate 23 provided on the bottom surface of the post-combustion unit 13. The ash conveyed to the chute 24 is discharged outside the waste incinerator 100. Although the post-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 section 11, the combustion section 12, and the post-combustion section 13 are different, the respective wall surfaces and the like are configured according to the reactions that occur. For example, a flame having a higher fire resistance level than that of the drying unit 11 is employed in the combustion unit 12 because flame combustion occurs.

  As described above, in the primary combustion zone 10 of the incinerator 1 of the present embodiment, the input waste is dried, burned, and post-burned. In the incinerator 1 of the present embodiment, since the respective constituent stages are clearly separated, the above three processes are performed stepwise. The present invention is applicable to incinerators of various configurations. For example, the present invention is also applicable to incinerators in which the constituent stages are not clearly divided. The present invention is also applicable to an incinerator where at least one of the drying stage and the post-combustion stage does not exist. The present invention is also applicable to an incinerator without a grate, for example, a fluidized bed incinerator or a fixed bed incinerator.

  The secondary combustion zone 14 is a space for secondary combustion. Secondary combustion refers to reacting unburned gas contained in the primary combustion gas with the gas for secondary combustion and burning. The secondary combustion gas is a gas containing oxygen supplied for secondary combustion. The secondary combustion gas includes secondary air, circulating exhaust gas, and a mixed gas thereof. The secondary air is air taken in from the outside and is not used for combustion or the like (that is, excluding circulating exhaust gas). By performing the secondary combustion, the combustion completeness can be advanced. The secondary combustion zone 14 extends upward from the drying section 11, the combustion section 12, and the post-combustion section 13, and secondary air is supplied along the way. Thereby, the primary combustion gas is mixed and stirred with the secondary air, and the unburned gas contained in the primary combustion gas is burned in the secondary combustion zone 14.

  <Supply of Primary Combustion Gas and Secondary Combustion Gas> The gas supply device 50 supplies gas (primary combustion gas and secondary combustion gas) into the combustion chamber 2. The gas supply device 50 of the present embodiment has a primary air supply unit 51, a secondary air supply unit 52, and an exhaust gas supply unit 53. Each supply unit is constituted by a blower for attracting or sending out gas.

  The primary air supply unit 51 supplies primary air to the combustion chamber 2 via the primary supply path 71. The primary supply path 71 is provided below the drying grate box 25 provided below the drying grate 21, the combustion step gaze box 26 provided below the combustion grate 22, and below the post-combustion grate 23. This is a path for supplying primary air to the post-combustion step wind box 27, respectively. In the primary supply path 71, a first damper 81 for adjusting the supply amount of primary air supplied to the drying step wind box 25, and a second damper 82 for adjusting the supply amount of primary air supplied to the combustion step wind box 26 are provided. , A third damper 83 for adjusting the supply amount of the primary air to be supplied to the post-combustion step wind box 27. As shown in FIG. 2, the first damper 81, the second damper 82, and the third damper 83 are controlled by the control device 90.

  Further, a heater may be provided in the primary supply path 71 so that the temperature of the primary air supplied to the combustion chamber 2 can be adjusted. Further, as described above, since the primary combustion gas also includes the circulating exhaust gas and the mixed gas, the primary combustion gas may be supplied to the combustion chamber 2. In the present embodiment, the primary combustion gas is supplied to the primary combustion zone 10 from below, but may be supplied from the side of the primary combustion zone 10 or the like. The primary combustion gas may be supplied to the upstream side of the primary combustion zone 10 as long as it is used for primary combustion.

  The secondary air supply unit 52 supplies the secondary air to the combustion chamber 2 via the secondary supply path 72. More specifically, the secondary air supply unit 52 supplies secondary air to the air gas holding space 16 of the incinerator 1 from an upper portion (ceiling part) thereof, and a portion where the combustion gas changes direction by the throttle unit 17. The secondary air is supplied to the secondary combustion zone 14 by supplying the secondary air to the vicinity of the throttle unit 17. The secondary supply path 72 is provided with a fifth damper 85 for adjusting the supply amount of the secondary air supplied to the vicinity of the air gas holding space 16 and the throttle unit 17. As shown in FIG. 2, the fifth damper 85 is controlled by the control device 90.

  The exhaust gas supply unit 53 supplies (recirculates) the exhaust gas discharged from the waste incinerator 100 through the circulating exhaust gas supply path 73 into the furnace. A part of the exhaust gas discharged from the waste incinerator 100 and purified by the dust collector 6 is supplied to the incinerator 1 from both sides (the front side and the rear side of the paper) of the combustion unit 12 by the exhaust gas supply unit 53. Is done. The position where the exhaust gas is supplied is not particularly limited. For example, the exhaust gas may be supplied from above the incinerator 1 (the ceiling) or may be supplied from only one side. By supplying the exhaust gas to the incinerator 1, the oxygen concentration in the incinerator 1 decreases, and a local excessive rise in the combustion temperature can be suppressed. As a result, generation of NOx can be suppressed. The circulation exhaust gas supply path 73 is provided with a fourth damper 84 that adjusts the supply amount of the circulation exhaust gas. As shown in FIG. 2, the fourth damper 84 is controlled by the control device 90.

  <Various sensors and control device> As shown in FIGS. 1 and 2, the incinerator 1 is provided with a plurality of sensors for grasping a combustion state and the like. Specifically, the incinerator 1 includes a primary combustion temperature sensor 91, a secondary combustion temperature sensor 92, a CO gas concentration sensor 93, a NOx gas concentration sensor 94, a boiler vapor amount sensor 95, and an imaging device 96. And are provided.

  The primary combustion temperature sensor 91 is disposed, for example, in the primary combustion zone 10 downstream of the air gas holding space 16 and upstream of the post-combustion unit 13, and detects a primary combustion temperature that is the temperature of the primary combustion zone 10. And outputs it to the control device 90. The secondary combustion temperature sensor 92 is disposed in the secondary combustion zone 14 downstream of the post-combustion section 13 and upstream of the boiler 30, and detects a secondary combustion temperature that is the temperature of the secondary combustion zone 14. And outputs it to the control device 90. The CO gas concentration sensor 93 is disposed downstream of the dust collector 6, and detects a CO gas concentration (CO gas concentration discharged from the incinerator) contained in the exhaust gas and outputs the detected CO gas concentration to the control device 90. The NOx gas concentration sensor 94 is disposed downstream of the dust collector 6 and detects the NOx gas concentration (NOx gas concentration discharged from the incinerator) contained in the exhaust gas and outputs the detected NOx gas concentration to the control device 90. The boiler steam amount sensor 95 is arranged on a path from the boiler 30 to the steam turbine power plant 35. The boiler steam amount sensor 95 detects the amount of steam passing through this route, that is, the amount of steam generated by the boiler 30 (boiler evaporation amount), and outputs the detected amount to the control device 90.

  In the present embodiment, two imaging devices 96 are provided. Each imaging device 96 has the same structure. Further, three or more imaging devices 96 may be provided. A plurality of imaging devices 96 are provided for the purpose of creating a three-dimensional video. Therefore, the relative positions of the plurality of imaging devices 96 are stored in advance. Note that the imaging device 96 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 a video (moving image). Is also good. Since image information obtained from continuously obtained still images is equivalent to video (moving image) information, any device has a function of obtaining a video.

  Further, the imaging device 96 is not an infrared camera for detecting a temperature or the like, but a camera for acquiring an image of the appearance (color, luminance, etc.) of the flame. Therefore, the image acquired by the imaging device 96 is an image showing the color, luminance, and the like of the flame in the furnace viewed from the viewpoint of the imaging device 96. Note that the viewpoint indicates a position where the imaging device 96 as a measuring instrument is arranged. Each imaging device 96 aims to acquire an image of a flame that has been generated in the primary combustion and that has reached the secondary combustion zone 14 from the primary combustion zone 10. Therefore, the imaging device 96 is arranged at a position where the secondary combustion zone 14 is included in at least a part of the imaging range. Specifically, the imaging device 96 is disposed on a wall constituting the secondary combustion zone 14. Here, as shown in FIG. 3, a direction perpendicular to both the transport direction of the waste on the grate and the vertical direction (vertical direction) is referred to as a furnace width direction. The imaging device 96 of the present embodiment acquires an image via a window 14b formed on the back wall 14a provided at the downstream end in the transport direction. The window portion 14b is a portion for observing the inside of the furnace. Specifically, a part of the back wall 14a is opened, and the opening is closed with a transparent (including translucent) heat-resistant glass or the like. Part of the configuration. Further, instead of the back wall 14a, the imaging device 96 may be provided on the side wall 14c which is the end in the furnace width direction.

  As described later, in the present embodiment, the flame cross-section is calculated based on the three-dimensional image of the flame. However, the control is performed using not the specific value of the flame cross-section but the amount of change, so that the flame is surrounded. It is not necessary to arrange the imaging device 96 as described above. Therefore, the object of the present invention can be achieved even when the imaging device 96 is arranged only on the back wall 14a as in the present embodiment. However, by arranging a plurality of imaging devices 96 on, for example, the side wall 14c in addition to the back wall 14a, an image of a flame in a wider range can be created. The positions of the two imaging devices 96 in the vertical direction may be the same, or the positions in the vertical direction may be different if the imaging ranges do not greatly differ.

  <Process Performed by Control Device> The control device 90 includes 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 97 includes a CPU, a RAM, a ROM, and the like, and can perform a process of creating a three-dimensional image (image combining process) based on the images acquired by the two imaging devices 96. In the present embodiment, the control device 90 and the image processing device 97 are separate hardware, but one piece of hardware may have the functions of both the control device 90 and the image processing device 97. Hereinafter, the combustion control performed by the control device 90, particularly the control performed by analyzing a three-dimensional image, will be described with reference to the flowchart of FIG. FIG. 4 is a flowchart showing control performed by control device 90 to stabilize the boiler evaporation amount.

  First, the control device 90 stores a three-dimensional image created by the image processing device 97 based on images acquired by a plurality (two) of imaging devices 96 (S101). The process of creating a three-dimensional video (a plurality of temporally continuous three-dimensional images) from a plurality of videos (each image) will be briefly described because it is a known technique. Here, in order to distinguish the two imaging devices 96, the first and second imaging devices 96 are sometimes described. The image acquired by the first imaging device shows the color and shape of the surface of the flame viewed from the position of the first imaging device. The same applies to the video acquired by the second imaging device. Then, the image processing device 97 specifies where the specific portion A on the surface of the flame is displayed in each of the two images. Since the positional relationship between the first imaging device and the second imaging device is known as described above, the distance from the first or second imaging device to the specific location A of the flame can be calculated based on trigonometry or the like. By performing this process on other portions of the flame surface, the position (three-dimensional coordinates) of the flame surface can be specified.

  Next, the control device 90 calculates (1) a temporal change in the flame cross-sectional area and (2) a temporal change in the flame velocity based on the three-dimensional image stored in step S101 (S102).

  The flame cross-sectional area is a cross-sectional area when the flame of the three-dimensional image is cut along a predetermined virtual plane. Generally, the larger the flame in the secondary combustion zone 14, the greater the amount of heat generated in the combustion chamber 2. Therefore, the flame cross section serves as an index of the amount of heat currently being generated. In particular, the cross-sectional area obtained from the flame of the three-dimensional image is different from the conventional two-dimensional image of the flame and serves as an index of the amount of heat in consideration of the size of the flame in the depth direction viewed from the imaging device 96.

  As shown in FIG. 3, the virtual plane 101 is a plane that intersects the flow path of the combustion gas (specifically, the primary combustion gas generated by the primary combustion and the secondary combustion gas generated by the secondary combustion). The flow path of the combustion gas is a direction in which the combustion gas is directed as a whole (in other words, a direction in the secondary combustion zone 14 toward the boiler 30). Further, it is more preferable that the virtual plane 101 is orthogonal to the flow path of the combustion gas. In FIG. 3, in order to make the position of the virtual plane 101 easy to understand, the outline of the virtual plane 101 is drawn to divide the range of the virtual plane 101. However, in practice, in order to properly calculate the flame cross-sectional area even when the position or shape of the flame changes, a range having a large spread in the furnace width direction and the transport direction should be the virtual plane 101. It is preferable to set an imaginary plane extending to infinity without defining a contour or the like.

  The area of the virtual cross section 102 when the flame of the three-dimensional image is cut by the virtual plane 101 is the flame cross section. Here, as described above, in the present embodiment, since the entire image around the flame has not been obtained, the shape of the flame on the throttle unit 17 side, for example, cannot be specified. Accordingly, the control device 90 creates the virtual cross section 102 by drawing the contour of the virtual cross section 102 in the range of the flame created by the three-dimensional image, and performing linear interpolation or the like on the portion not specified in the three-dimensional image. I do. The control device 90 stores the calculated flame cross-sectional area in association with the time. The control device 90 performs this process on the three-dimensional image at each time to calculate and store the time change of the flame cross-sectional area (flame cross-sectional area at each time).

  The flame velocity is the gas velocity in the direction along the flow path of the combustion gas passing through the flame surface at the position of the virtual plane 101 described above. In general, the more the combustion gas is generated in the combustion chamber 2 (that is, the larger the amount of heat generated in the combustion chamber 2), the faster the flame velocity is likely to be. Therefore, the flame velocity is an index of the amount of heat currently being generated.

  The control device 90 calculates the flame velocity from the movement of the flame based on the virtual plane 101 and the three-dimensional image near the vertical plane. The flame velocity varies depending on the position of the virtual plane 101 in the horizontal direction. For example, the average velocity in a predetermined range is calculated to determine the flame velocity at the corresponding time. In the present embodiment, the position at which the flame velocity is calculated matches the position at which the flame cross-sectional area is calculated, but may be different. That is, the control device 90 may perform a process of calculating the flame velocity on the upstream or downstream side of the virtual plane 101. The control device 90 performs this process on the three-dimensional image at each time to calculate and store the time change of the flame velocity (flame velocity at each time).

  The method of calculating the flame cross-sectional area and the flame velocity and obtaining an index of the amount of heat currently generated in the combustion chamber 2 is performed using the flame present in the primary combustion zone 10 instead of the secondary combustion zone 14. You can also. However, in the primary combustion zone 10, the flame is not stable due to the presence of various unburned wastes, and the accuracy of this index may be significantly reduced. The flame reaching zone 14 is used.

  The control device 90 acquires the secondary combustion temperature detected by the secondary combustion temperature sensor 92 (S103). The control device 90 stores the time change of the secondary combustion temperature (the secondary combustion temperature at each time). Naturally, the higher the secondary combustion temperature, the greater the amount of heat generated in the combustion chamber 2. Therefore, the secondary combustion temperature is an index of the amount of heat currently being generated.

  Further, the control device 90 acquires the boiler evaporation amount detected by the boiler steam amount sensor 95 (S104). The control device 90 stores the time change of the boiler evaporation amount (the boiler evaporation amount at each time). Since steam is generated in the boiler 30 in accordance with the amount of heat generated in the combustion chamber 2, there is a high correlation between the amount of heat generated in the combustion chamber 2 and the amount of boiler evaporation. However, since there is a time lag before steam is generated in the boiler 30 due to the heat generated in the combustion chamber 2, strictly speaking, the amount of heat generated shortly before in the combustion chamber 2 and the current boiler evaporation amount And have a high correlation. Therefore, for example, even when the supply amount of the primary air or the secondary air is changed based on the current boiler evaporation amount, the effect of changing the supply amount does not affect the boiler evaporation amount. Since it takes time, it is not easy to sufficiently stabilize the boiler evaporation. In this regard, in the present embodiment, the combustion state can be controlled on the basis of the amount of heat currently generated in the combustion chamber 2 by performing the processing in step S105 and subsequent steps, so that the boiler evaporation amount is further stabilized. It becomes possible.

  Next, the controller 90 calculates a relative change amount for each of the flame cross-sectional area / flame velocity / secondary combustion temperature (S105, analysis step). The relative change is a difference between an instantaneous value and a steady value. The steady value is a measure of a value obtained in a state where the amount and properties of the waste put into the incinerator 1 and the combustion state of the waste are averaged. The steady value is calculated, for example, by obtaining an average value for a relatively long period. When calculating the average value, the average value may be calculated by excluding data clearly higher or lower than the others. The instantaneous value is a value obtained at a certain time. As described above, the flame cross-sectional area / flame flow velocity / secondary combustion temperature are all values relating to the amount of heat currently generated in the combustion chamber 2. Therefore, the relative change amount is an index indicating how much or less heat is currently generated in the combustion chamber 2 as compared with the past average state. The control device 90 stores the time change of the calculated relative change amount (the relative change amount at each time) for each of the flame cross-sectional area / flame flow velocity / secondary combustion temperature.

  Next, the control device 90 calculates correlation information indicating the relationship between the relative change amount and the change amount of the boiler evaporation amount for each of the flame cross-sectional area / flame velocity / secondary combustion temperature (S106, analysis). Process). Each of the flame cross section / flame flow rate / secondary combustion temperature is a value related to the amount of heat currently generated in the combustion chamber 2, and the amount of change in the boiler evaporation is determined by the amount of heat generated in the combustion chamber 2 just before. Related value. Therefore, by comparing the behavior in which the relative change amount fluctuates according to the time and the behavior in which the boiler evaporation amount fluctuates according to the time, it is possible to calculate a standard of the time delay. Then, by offsetting the boiler evaporation by the time delay and comparing the magnitude of the relative change with the magnitude of the boiler evaporation change, the effect of the relative change on the boiler evaporation change Can be specifically calculated. For example, it is possible to calculate a relational expression (corresponding to correlation information) for obtaining the change amount of the boiler evaporation amount using the relative change amount as a variable. For example, in a time zone in which the flame cross-sectional area changes, and in a time zone in which the flame velocity and the secondary combustion temperature hardly change, the correlation between the relative change amount of the flame cross-sectional area and the change amount of the boiler evaporation amount. Information can be obtained more appropriately. The correlation information of each of the flame cross-sectional area / flame flow velocity / secondary combustion temperature may be newly calculated each time a change in the boiler evaporation is predicted, or the correlation information once calculated may be calculated for at least a predetermined time. May be used continuously.

  Next, the control device 90 calculates a predicted change amount of the boiler evaporation amount based on the latest relative change amount and the correlation information for each of the flame cross-sectional area / flame velocity / secondary combustion temperature (S107, analysis). Process). The correlation information indicates the relationship between the relative change amount and the change amount of the boiler evaporation amount. Therefore, based on the latest relative change amount and the correlation information, it is possible to calculate how much the boiler evaporation amount will change from now. In particular, in the present embodiment, since this processing is performed for each of the flame cross-sectional area / flame velocity / secondary combustion temperature, it is possible to calculate an accurate predicted change amount of the boiler evaporation amount.

  Next, the control device 90 determines the supply conditions of the primary combustion gas and the secondary combustion gas for stabilizing the boiler evaporation amount based on the instantaneous value and the predicted change amount of the boiler evaporation amount (S108). , Control process). The predicted value of the boiler evaporation amount can be estimated based on both the instantaneous value of the boiler evaporation amount and the predicted change amount. For example, by comparing the predicted value with the target value, it is possible to accurately determine whether to increase or decrease the boiler evaporation amount. For example, when it is determined that the boiler evaporation amount should be increased, the control device 90 increases the supply amounts of the primary combustion gas and the secondary combustion gas, for example, to promote the combustion. In addition to or instead of the process of changing the gas supply amount, for example, the ratio of the circulating exhaust gas to the primary combustion gas, the setting of the heater when the primary combustion gas is heated by the heater, or the primary combustion gas The ratio (supply condition) of the secondary combustion gas to the gas may be changed. By performing this process, the combustion control can be performed based on the amount of heat currently generated in the combustion chamber 2 instead of the amount of heat generated in the combustion chamber 2 in the past (current amount of boiler evaporation). The amount can be made more stable.

  Further, after step S108, the control device 90 newly acquires data (S101-S104), updates the correlation information as necessary (S105, S106), and estimates the newly calculated boiler evaporation amount. The supply conditions of the primary combustion gas and the secondary combustion gas are further changed based on the change amount and the like (S107, S108). Thus, even when the amount of heat generated in the combustion chamber 2 changes, the control necessary for stabilizing the boiler evaporation amount can be performed immediately in response to the change.

  Note that the combustion generated in the incinerator 1 greatly differs depending on the shape and structure of the incinerator 1 and the waste to be charged. Further, the target state greatly differs depending on the required processing amount, the durability of the incinerator 1, the regulations on exhaust gas, and the like. Further, the supply conditions of the primary combustion gas and the secondary combustion gas are determined in consideration of not only the boiler evaporation amount but also the detection results of other sensors (for example, the primary combustion temperature sensor 91 to the NOx gas concentration sensor 94). You. Due to such circumstances, even when the predicted value of the boiler evaporation amount is lower than the target value, the control for increasing the primary combustion gas and the secondary combustion gas may not be performed in some cases.

  As described above, according to the aspects of the present invention, the following in-furnace state determination method is provided. In other words, the method for determining the state of the furnace includes a primary combustion zone 10 for performing primary combustion using the primary combustion gas, and a primary combustion gas containing an unburned gas generated in the primary combustion. The combustion is performed on a waste incinerator 100 including a combustion chamber 2 having a secondary combustion zone 14 for performing secondary combustion. The in-furnace situation determination method performs a process including an image acquisition step, a three-dimensional image creation step, a flame cross-sectional area calculation step, and a flame velocity calculation step. In the image acquisition step, images of the flames that have reached the secondary combustion zone 14 from the primary combustion zone 10 are acquired using a plurality of imaging devices 96 having different viewpoints. In the three-dimensional image creation step, a three-dimensional image including the flame of the secondary combustion zone 14 is created by performing image synthesis processing on a plurality of images from different viewpoints acquired in the image acquisition step. In the flame cross-sectional area calculation step, by analyzing the three-dimensional image, the flame cross-sectional area of the secondary combustion zone 14 cut by a predetermined virtual plane intersecting the flow path of the combustion gas generated in the primary combustion or the secondary combustion is calculated. Calculate the time change. In the flame velocity calculation step, the time change of the flame velocity in the direction along the flow path of the combustion gas generated in the primary combustion or the secondary combustion is calculated by analyzing the three-dimensional image.

  Thus, an accurate index of the amount of heat currently generated in the combustion chamber 2 can be obtained by using the flame cross-sectional area and the flame velocity of the secondary combustion zone 14.

  Further, the in-furnace condition determining method of the present embodiment includes a secondary combustion temperature detecting step and an analyzing step. In the secondary combustion temperature detecting step, a time change of the secondary combustion temperature, which is the temperature of the secondary combustion zone 14, is detected. In the analysis step, a process of calculating a relative change amount which is a magnitude of an instantaneous value with respect to a steady value is performed based on each time change of the flame cross-sectional area, the flame velocity, and the secondary combustion temperature.

  Thus, the in-furnace situation can be determined using an accurate index of the amount of heat currently generated in the combustion chamber 2 as compared with the average state (normal state).

  In addition, the in-furnace state determination method of the present embodiment includes a boiler evaporation amount obtaining step of obtaining a boiler evaporation amount accompanying heat recovery from exhaust gas discharged from the combustion chamber 2. In the analysis step, correlation information indicating the relationship between the relative change amount and the change amount of the boiler evaporation amount after the time delay is further calculated for each of the flame cross-sectional area, the flame velocity, and the secondary combustion temperature. For each of the flame cross-sectional area, the flame velocity, and the secondary combustion temperature, the predicted change amount of the boiler evaporation is calculated based on the calculated or detected instantaneous value and the correlation information.

  Thus, the boiler evaporation amount can be estimated using an accurate index of the amount of heat currently generated in the combustion chamber 2.

  Further, in the evaporation amount control method of the present embodiment, the boiler evaporation amount is controlled based on information obtained by using the in-furnace state determination method. This evaporation amount control method is based on the predicted change amount of the boiler evaporation amount calculated in the analysis step and the boiler evaporation amount obtained in the boiler evaporation amount acquisition step, and based on the primary combustion gas and the secondary combustion gas. And a control step of adjusting at least one of the supply conditions.

  This makes it possible to adjust the gas supply conditions using the estimated accurate boiler evaporation amount, so that the boiler evaporation amount can be stabilized.

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

  Note that the processing in steps S101 to S104 is processing for acquiring or storing (updating) data necessary for the processing in step S105 and thereafter, and therefore the order of the processing may be different. Further, in step S102, the process of calculating the flame cross-sectional area and the process of calculating the flame flow velocity may be performed first or simultaneously.

  In the above embodiment, the supply conditions of the primary combustion gas and the secondary combustion gas are changed based on the predicted value of the boiler evaporation amount. In addition, the speed of the dry grate 21, the combustion grate 22, and the post-combustion grate 23 may be controlled based on the predicted value of the boiler evaporation.

1 incinerator (waste incinerator)
Reference Signs List 90 Control device 95 Boiler steam amount sensor 96 Imaging device 97 Image processing device 100 Waste incineration equipment

Claims (4)

A primary combustion zone for performing primary combustion using the primary combustion gas, and a secondary combustion for performing primary combustion gas containing unburned gas generated in the primary combustion using the secondary combustion gas. For waste incineration equipment with a combustion chamber with a secondary combustion zone,
Using a plurality of imaging devices having different viewpoints, an image acquisition step of acquiring an image of a flame that has reached the secondary combustion zone from the primary combustion zone,
A three-dimensional image creating step of creating a three-dimensional image including a flame of the secondary combustion zone by performing image combining processing on a plurality of images from different viewpoints acquired in the image acquiring step;
By analyzing the three-dimensional image, a flame for calculating a time change of a flame cross-sectional area of the secondary combustion zone cut by a predetermined virtual plane intersecting a flow path of a combustion gas generated in the primary combustion or the secondary combustion A cross-sectional area calculation step;
By analyzing the three-dimensional image, a flame velocity calculation step of calculating a time change of the flame velocity in a direction along a flow path of the combustion gas generated in the primary combustion or the secondary combustion,
A method for judging an in-furnace situation, characterized by performing a process including: It is a furnace situation determination method according to claim 1,
A secondary combustion temperature detection step of detecting a temporal change in a secondary combustion temperature that is a temperature of the secondary combustion zone,
An analysis step of performing a process of calculating a relative change amount, which is a magnitude of an instantaneous value with respect to a steady-state value, based on each time change of the flame cross-sectional area, the flame velocity, and the secondary combustion temperature,
A method for judging an in-furnace situation, comprising: The method for judging an in-furnace situation according to claim 2, wherein
Including a boiler evaporation amount obtaining step of obtaining a boiler evaporation amount associated with heat recovery from exhaust gas discharged from the combustion chamber,
In the analysis step, further,
For each of the flame cross-sectional area, the flame velocity, and the secondary combustion temperature, the relative change amount, and the change amount of the boiler evaporation amount after the time delay, calculate correlation information indicating a relationship,
For each of the flame cross-sectional area, the flame velocity, and the secondary combustion temperature, a predicted change in the boiler evaporation is calculated based on the calculated or detected instantaneous value and the correlation information. Judgment method. An evaporation amount control method for controlling a boiler evaporation amount using the in-furnace state determination method according to claim 3,
At least one of the primary combustion gas and the secondary combustion gas based on the predicted change amount of the boiler evaporation amount calculated in the analysis step and the boiler evaporation amount acquired in the boiler evaporation amount acquisition step. A control step of adjusting supply conditions of the evaporation amount.

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