JP6671326B2 - Combustion control method and waste incinerator - Google Patents

Description

  The present invention relates to a method for properly maintaining stable combustion in a grate-type waste incinerator that incinerates waste while transporting the waste by a grate.

  Since various kinds of wastes are put into a waste incinerator, it is important that stable combustion can be appropriately maintained even when the properties of the put wastes change. Here, the grate-type waste incinerator is divided into a drying section for drying the waste, a combustion section for burning the waste by flame, and a post-combustion section for post-burning the waste (oki combustion). ing. However, depending on the nature of the waste, post-combustion may occur in a part of the combustion part, or flame combustion may occur in a part of the post-combustion part. In order to realize stable combustion, it is important to keep the position of the burn-off point, which is the end position of such flame combustion, within an appropriate range.

  Patent Literature 1 discloses an incinerator in which an in-furnace camera is arranged further downstream in the transport direction than a post-combustion unit to acquire an image of the inside of the furnace. In this incinerator, by analyzing the images acquired by the camera inside the furnace, the combustion position (the point on the camera inside the furnace where the combustion of waste is most active) and the burnout point are measured, and the measurement results Based on this, the speed of the stoker (grate) is controlled.

  Patent Literature 2 discloses an incinerator configured to detect a layer thickness and a burn-out point of waste in the furnace. In this incinerator, the oxygen content of the combustion air supplied through the stoker is controlled by the detection signal of one or both of the waste layer thickness and the burn-out point, thereby achieving the waste layer thickness. Is held at a set value, or the burn-out point is held at a set position.

  Patent Literature 3 discloses an incinerator in which an infrared camera is arranged on a ceiling wall in a furnace, and a temperature distribution in the furnace is detected and analyzed to detect the positions of an ignition point and a burn-out point. In this incinerator, the amount of air to be supplied is adjusted for each of a plurality of blocks constituting the combustion section, based on the positions of the ignition point and the burn-off point and other data.

  Patent Document 4 discloses measuring a temperature distribution in a furnace and determining at least one of a combustion start position and a burnout position on a grate in a front-back direction with respect to a preset reference range. Are disclosed. In this incinerator, it is determined whether at least one of the combustion start position and the burn-out position is a reference range, a position closer to the reference range, or a position closer to the reference range. Then, according to the determination result, the distribution ratio between the recirculated exhaust gas supplied from the front ceiling wall toward the rear and the recirculated exhaust gas supplied from the rear wall or the rear ceiling wall toward the front is changed. Is done.

Japanese Patent No. 3099229 JP-A-2002-206722 JP 2003-161422 A JP 2014-167353 A

  However, as disclosed in Patent Documents 1 and 2, it is difficult to control the position of the burn-off point based on the information on the combustion position and the burn-off point so that the burn-off point falls within an appropriate range. It was difficult with a grid-type waste incinerator. Further, in Patent Literature 1, since the in-furnace camera is disposed at a relatively low position downstream of the post-combustion section in the transport direction, it is difficult to obtain an image on the upstream side of the flame because the flame is in the way. It will be difficult.

  In Patent Literature 3, the purpose is to detect both the ignition point and the burn-off point, and an infrared camera is arranged on the ceiling wall of the combustion unit. When an infrared camera is arranged at this position, a flame (high-temperature portion) may be located between the infrared camera and the ignition point depending on the height of the flame. In this case, the position of the ignition point cannot be detected. Further, when an infrared camera is arranged on the ceiling wall, there is a possibility that the infrared camera is affected by infrared rays generated by pyrolysis gas, combustion gas, and the like. Further, Patent Document 4 describes that a combustion start position and a burn-out position are detected by using a temperature distribution measured by an infrared camera in the same manner as Patent Document 3, and thus the same problem as Patent Document 3 is described. Exists.

  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 detecting information necessary for keeping a burn-off point within an appropriate range.

  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.

According to a first aspect of the present invention, there is provided the following combustion control method . That is, this combustion control method comprises a grate divided into a drying section, a combustion section, and a post-combustion section, and intermittently operates in a state where the waste is loaded, thereby causing the waste to enter the furnace. This is performed for a waste incinerator that is transported toward the outlet and supplies the primary combustion gas through the grate. This combustion control method performs a process including an image acquisition step, a calculation step, and a control step . In the image acquisition step, from the window provided on the side wall formed at the end of the drying unit in the furnace width direction, at least the appearance of the waste placed on the boundary between the drying unit and the combustion unit Get the video including. In the calculation step, the flame combustion start position is specified based on the image acquired in the image acquisition step, and it is calculated whether the flame combustion start position is moving upstream in the transport direction or downstream in the transport direction. I do. In the waste incinerator, the primary combustion performed in the drying section, the combustion section, and the post-combustion section, and the secondary combustion for burning the primary combustion gas including the unburned gas generated in the primary combustion, Do. In the control step, when it is calculated that the flame combustion start position has moved 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 unit. In the control step, when it is calculated that the flame combustion start position has moved to the downstream side in the transport direction, control is performed to reduce the transport speed of the waste by the grate of the drying unit. In the control step, the supply amount of the secondary combustion gas is adjusted based on whether the flame combustion start position is moving upstream in the transport direction or downstream in the transport direction.

According to a second aspect of the present invention, there is provided a waste incinerator having the following configuration. That is, this waste incinerator includes a transport unit, a wind box, an imaging device, and a control device. The transfer section is constituted by a grate divided into a drying section, a combustion section, and a post-combustion section, and intermittently operates in a state where the waste is placed, thereby directing the waste to a furnace outlet. Transport. The wind box is provided below each of said grate, primary combustion gas to be supplied to the waste through the grate is supplied. The imaging device is configured such that, from a window provided on a side wall formed at an end of the drying unit in the furnace width direction, a downstream side of a central portion in a transport direction of the drying unit and a transport of the combustion unit. An image of the appearance of the waste at least partially upstream of the central part in the direction. The control device specifies a flame combustion start position based on the image acquired by the imaging device, and calculates whether the flame combustion start position is moving upstream in the transport direction or downstream in the transport direction. When it is calculated that the flame combustion start position has moved to the upstream side in the transport direction, the control device performs control to increase the transport speed of the waste by the grate of the drying unit. When it is calculated that the flame combustion start position has moved to the downstream side in the transport direction, the control device performs control to reduce the transport speed of the waste by the grate of the drying unit. The controller adjusts the supply amount of the secondary combustion gas based on whether the flame combustion start position is moving upstream in the transport direction or downstream in the transport direction.

  In a grate-type incinerator, it is important to keep the burn-off point (the end position of flame combustion), which is the boundary between combustion and post-combustion, within an appropriate range in order to realize stable combustion. Here, according to the inventor of the present application, (1) the main cause of the burn-out point deviating from an appropriate range 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, a burn-off point based on change information of a burn-off point or a burn-off point at which a state change appears after a considerable time delay from the occurrence of a difference between the assumed drying time and the actual drying time. It has been discovered that it is actually difficult to control the position. Further, the moving direction of the flame combustion start position corresponds to the tendency of the difference between the assumed drying time and the actual drying time (that is, the appropriateness of the progress of the drying and burning of the waste). It can be handled as information necessary to fit within the range.

In addition, since the side wall of the combustion section becomes extremely hot and it is difficult to install a window and an image pickup device, etc., by providing a window on the side wall of the drying section, an image for specifying the flame combustion start position can be appropriately provided. Can be obtained. Further, unlike the ceiling wall and the like, the side wall is hardly affected by the pyrolysis gas and the combustion gas generated in the furnace, so that it is possible to appropriately acquire an image for specifying the flame combustion start position.
In addition, by performing control to change the transfer speed of the grate in the drying unit, 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 more appropriately performed. can do. As a result, the burn-off point can be set within an appropriate range, and stable combustion can be maintained.
In addition, since the progress of the primary combustion (that is, the amount of generated primary combustion gas, etc.) can be estimated based on the moving direction of the flame combustion start position, the supply amount of the secondary combustion gas is adjusted accordingly. Accordingly, in the secondary combustion, the unburned gas contained in the primary combustion gas can be sufficiently burned.

  ADVANTAGE OF THE INVENTION According to this invention, the method of detecting the information required in order to put a burn-off point in an appropriate range can be provided.

The schematic block diagram of the waste incineration equipment containing the incinerator of one Embodiment of this invention. Functional block diagram of an incinerator. FIG. 2 is a three-dimensional schematic view of an incinerator showing an attachment position of an imaging device. 9 is a flowchart showing control performed by the control device to stabilize combustion. The schematic block diagram of the waste incineration equipment which shows a state when the flame combustion start position moves to the upstream side. The schematic block diagram of the waste incineration equipment which shows a state when the flame combustion start position moves to the downstream side.

  <Overall Configuration of Waste Incineration Facility> First, a waste incineration facility 100 including an 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 according to one embodiment of the present invention. In the following description, simply describing upstream and downstream means upstream and downstream in the direction in which waste, combustion gas, exhaust gas, primary air, secondary air, circulating exhaust gas, and the like flow.

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

  The boiler 30 generates steam using heat generated by burning 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 in the water pipe 31 and the superheater pipe 32 is supplied to a steam turbine power generation facility 35.

  The steam turbine power generation facility 35 is configured to include a turbine and a power generation device (not shown). The turbine is rotationally driven by the 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.

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

  <Configuration of Incinerator 10> The incinerator 10 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 moving speed, the number of movements per unit time, the moving amount (stroke), and the position of the stroke end (moving range) of the dust feeding device main body 42 are controlled by the control device 90. 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 drying unit 11, the combustion unit 12, and the post-combustion unit 13 by the transport unit 20 in this order. 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 operates in the order of forward, stop, reverse, stop, etc. The waste can be agitated while being transported downstream. By increasing (decreasing) the operating speed of the movable grate, the conveying speed of the waste can be increased (decreased). Further, by shortening (longing) the stop time of the movable grate, the transport speed of the waste can be increased (decreased). The grate is arranged side by side with a gap large enough to allow gas to pass through.

  The drying unit 11 is a unit that dries the waste supplied to the incinerator 10. The waste in the drying section 11 is dried by the primary air supplied from below the drying grate 21 and the radiant heat of combustion in the adjacent combustion section 12. At this time, pyrolysis gas is generated from the waste in the drying unit 11 by the 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 section 12, the ash generated by the combustion, and the unburned matter that has not been completely burned are conveyed by the combustion grate 22 toward the post-combustion section 13. Further, the combustion gas and the flame generated in the combustion section 12 pass through the throttle section 17 and flow toward the post-combustion section 13. Although the combustion grate 22 is provided at the same height as the dry grate 21, it 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 combustion gas and the primary air promote the combustion of the unburned substances that cannot be 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, since flame combustion occurs in the combustion section 12, a structure having a higher fire resistance level than the drying section 11 is employed.

  The reburning section 14 is a section for burning unburned gas contained in the combustion gas. The reburning portion 14 extends upward from the drying portion 11, the burning portion 12, and the afterburning portion 13, and secondary air is supplied along the way. 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 section 14. The combustion that occurs in the combustion unit 12 and the post-combustion unit 13 is referred to as primary combustion, and the combustion that occurs in the reburn unit 14 (that is, the combustion of 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 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.

  In this specification, the gas supplied for primary combustion is referred to as 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 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. Similarly, in this specification, the gas supplied for secondary combustion is referred to as 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 primary air.

  The primary air supply unit 51 supplies primary air into the furnace via a 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. Note that a heater may be provided in the primary air supply path 71 so that the temperature of the primary air supplied to each section can be adjusted.

  The first supply path 71 a is a path for supplying primary air to the drying step wind box 25 provided below the drying grate 21. The first supply path 71a is provided with a first damper 81, and can adjust the supply amount of the primary air supplied to the drying step wind box 25. 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 step box 26 provided below the combustion grate 22. A second damper 82 is provided in the second supply path 71b, so that the supply amount of the primary air supplied to the combustion step wind box 26 can be adjusted. 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 staircase box 27 provided below the post-combustion grate 23. The third supply path 71c is provided with a third damper 83, and can adjust the supply amount of the primary air supplied to the post-combustion step wind box 27. 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) of the incinerator 10 through the secondary air supply path 72, and the combustion gas is supplied by the throttle unit 17. The secondary air is supplied to the portion that changes direction (near the throttle unit 17). Further, a fourth damper 84 controlled by the control device 90 is provided in the secondary air supply path 72, so that the supply amount of the secondary air to each section can be adjusted.

  The exhaust gas supply unit 53 supplies (recirculates) the exhaust gas discharged from the waste incinerator 100 via the circulating exhaust gas supply path 73 into the furnace. Exhaust gas discharged from the waste incinerator 100 is purified by a filtration type dust collector 60, and a part of the exhaust gas is incinerated from both sides of the combustion unit 12 (the front side and the rear side of the paper) by the exhaust gas supply unit 53. It is supplied to the furnace 10. The position where the exhaust gas is supplied is not particularly limited. For example, the exhaust gas may be supplied from above the incinerator 10 (the ceiling) or may be supplied from only one side. By supplying the exhaust gas to the incinerator 10, the oxygen concentration in the incinerator 10 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 fifth damper 85 controlled by the control device 90, and can adjust the supply amount of the circulation exhaust gas.

  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, and a NOx gas concentration sensor 94 are provided.

  The incinerator gas temperature sensor 91 is disposed in the incinerator 10 (for example, downstream of the air gas holding space 16 and upstream of the post-combustion unit 13), and detects the gas temperature in the incinerator to control the controller 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), and detects the incinerator outlet gas temperature and outputs it to the control device 90. I do. The CO gas concentration sensor 93 is disposed downstream of the dust collector 60, 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 60, detects the NOx gas concentration (NOx gas concentration discharged from the incinerator) contained in the exhaust gas, and outputs it to the control device 90.

  The imaging device 95 aims to acquire an image (still image or moving image) of the flame combustion start position. Further, the imaging device 95 is not an infrared camera for detecting a temperature or the like, but a camera for acquiring an image of the appearance of the waste. In the incinerator 10, it is assumed that the drying is completed at the downstream end of the drying unit 11 and the flame combustion is started at the upstream end of the combustion unit 12. However, depending on the properties of the supplied waste (for example, the amount of water contained in the waste and the easiness of burning the waste), drying is completed in the middle of the drying unit 11 to start flame combustion or combustion. Drying may not be completed and flame combustion may not start even in the middle of the part 12.

  Therefore, the imaging device 95 acquires at least an image of the boundary between the drying unit 11 and the combustion unit 12 (specifically, an image of the waste placed on this boundary). In the present embodiment, since the flame combustion start position is imaged even when the flame combustion start position moves significantly, the imaging range of the imaging device 95 is set such that the combustion range starts from the downstream side of the center of the drying unit 11 in the transport direction. The range extends from the center of the portion 12 in the transport direction to the upstream side. Further, the imaging device 95 of the present embodiment is different from a general imaging device in that a range downstream of the center in the transport direction of the combustion unit 12 (that is, a boundary between the combustion unit 12 and the post-combustion unit 13, The post-combustion unit 13) is not included in the imaging range. Note that, depending on the shape of the furnace (for example, the length of the grate in the transport direction), a configuration in which an image in a narrower range in the transport direction than in the present embodiment may be obtained.

  As shown in FIG. 3, a direction perpendicular to the direction in which the waste is transported and the vertical direction (vertical direction) is referred to as a furnace width direction. The imaging device 95 acquires an image from a side wall 11a which is a wall formed at an end of the drying unit 11 in the furnace width direction. Specifically, a window 11b is provided on the side wall 11a, and the imaging device 95 acquires an image via the window 11b. The window portion 11b is a portion for observing the inside of the furnace. Specifically, the window portion 11b has a configuration in which a part of the side wall 11a is opened and the opening is closed with a transparent (including translucent) heat-resistant glass or the like. Part.

  The imaging device 95 is arranged on the side wall of the drying unit 11 and is arranged to be inclined toward the downstream side in the transport direction in order to acquire an image downstream of the drying unit 11. Further, the imaging device 95 is arranged at a position higher than the waste for the purpose of appropriately acquiring an image even when the amount of the waste accumulated becomes large. Therefore, the imaging device 95 is arranged to be inclined downward. In addition, if the image of the flame combustion start position can be acquired, the imaging device 95 may be arranged without being inclined.

  In the present embodiment, the imaging device 95 is arranged only on one of the left and right side walls 11a, but the imaging device 95 may be arranged on both the side walls 11a. Further, a configuration in which a plurality of imaging devices 95 are arranged at different angles on one side wall 11a to capture a wide range of video may be adopted. Alternatively, a configuration in which the imaging range can be changed without stopping the incinerator 10 by arranging the imaging device 95 that can change the imaging range may be adopted.

  <Control 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 incinerator 100. Hereinafter, the combustion control performed by the control device 90 (particularly, the control performed by analyzing the image acquired by the imaging device 95) will be described with reference to the flowchart of FIG. FIG. 4 is a flowchart showing control performed by the control device to stabilize combustion.

  First, the control device 90 specifies and stores the flame combustion start position based on the image acquired by the imaging device 95 (S101). The flame combustion start position is a position in the transport direction at which flame combustion starts. Since the image acquired by the imaging device 95 includes flame combustion, the flame is specified based on the luminance and hue and the like, and the position of the upstream end of the flame is determined to obtain the flame combustion start position. Can be specified. Although the flame combustion start position is not uniform in the furnace width direction, the flame combustion start position calculated by obtaining, for example, the average of the flame combustion start position in the furnace width direction is stored.

  Next, the control device 90 determines whether or not the flame combustion start position has moved to the upstream side based on the time change of the flame combustion start position (S102). For example, when the amount of water contained in the waste supplied to the incinerator 10 is reduced or when flammable waste is supplied, the drying unit 11 dries the waste (and pyrolysis accompanying the drying). (The same applies hereinafter)), the time (actual drying time) actually required to shorten the time is shortened. Therefore, the actual drying time is shorter than the assumed drying time of the waste assumed in advance (a difference occurs). In this case, as shown in FIG. 5, since drying is completed in the middle of the drying unit 11, flame combustion occurs in the middle of the drying unit 11 (the flame combustion start position moves to the upstream side). .

  If this state is left unchecked, flame combustion proceeds in the drying unit 11, so that the residence time required for flame combustion in the combustion unit 12 is shortened. The post-combustion, which is the stage, starts gradually. As a result, the respective positions of drying, combustion, and post-combustion on the grate gradually move to the upstream side as a whole. The burn-off point (end position of flame combustion) is out of an appropriate range, and stable combustion cannot be maintained.

  In order to prevent this, the control device 90 basically determines that the flame combustion start position has moved to the upstream side (in the case of Yes in S102), and conveys the waste conveyance speed of the dry grate 21 ( Hereinafter, the transport speed is simply increased (S103). 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 alternatively or additionally, the stop time of the movable grate of the dry grate 21 is shortened. I do. Thus, it is possible to prevent a situation where the combustion position of each part on the grate moves to the upstream side. Therefore, since the burn-off point can be set within an appropriate range, stable combustion can be maintained.

  The combustion that occurs in the incinerator 10 varies greatly depending on the shape and structure of the incinerator 10 and the waste that is charged. Further, the target combustion state greatly differs depending on the required processing amount, the durability of the incinerator 10, the regulations on exhaust gas, and the like. Therefore, the controller 90 determines whether or not the transport speed of the dry grate 21 needs to be increased, not only whether the flame combustion start position has moved to the upstream side, but also other detection data (for example, gas temperature in the incinerator). It is preferable that the determination be made based on data from the sensor 91 to the NOx gas concentration sensor 94 and the like.

  When it is determined that the flame combustion start position has not moved to the upstream side (No in S102), the control device 90 moves the flame combustion start position to the downstream side based on the time change of the flame combustion start position. It is determined whether or not there is (S104).

  For example, when the amount of water contained in the waste supplied to the incinerator 10 increases, or when non-flammable waste is supplied, the actual drying time for drying the waste in the drying unit 11 is reduced. become longer. Therefore, the actual drying time is longer (a difference occurs) than the assumed drying time of the waste assumed in advance. In this case, as shown in FIG. 6, since the drying is not completed at the downstream end of the drying unit 11, flame combustion starts in the middle of the combustion unit 12 (the flame combustion start position moves to the downstream side). Do).

  If this state is left unchecked, the required residence time for flame combustion in the combustion unit 12 is not ensured, so that flame combustion that should be completed in the combustion unit 12 shifts to the post-combustion unit 13, The post-combustion starts in the middle of the combustion section 13. As a result, the respective positions of drying, burning, and post-burning on the grate gradually move to the downstream side as a whole. The burn-out point falls out of an appropriate range, and stable combustion cannot be maintained.

  To prevent this, the control device 90 basically reduces the transport speed of the dry grate 21 when it is determined that the flame combustion start position is moving downstream (Yes in S104) ( S105). 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 alternatively or additionally, the stop time of the movable grate of the dry grate 21 is increased. I do. Thus, it is possible to prevent a situation where the combustion position of each part on the grate moves downstream. Therefore, since the burn-off point can be set within an appropriate range, stable combustion can be maintained. Further, the control device 90 determines whether or not the transport speed of the dry grate 21 needs to be reduced not only based on whether the flame combustion start position is moving downstream but also based on other detection data. Is preferred.

  In addition, assuming that a difference occurs between the actual drying time and the assumed drying time of the waste that has been assumed in advance, changing the transport speed of the drying grate 21 means that the drying grate 21 is actually supplied from the drying grate 21 to the combustion grate 22. This implies that the properties of the waste being used are already different from conventional assumptions. As a result, if the conveying speeds of the combustion grate 22 and the post-combustion grate 23 are made the same as in the related art in this state, the time required for combustion and post-combustion has already been changed, so that stable combustion cannot be maintained. .

  In order to prevent this, when the transport speed of the dry grate 21 is changed (Yes in S102 or S104), the control device 90 determines the property of the waste that is the cause of the change in the transport speed of the dry grate 21. The conveying speed of the combustion grate 22 and the post-combustion grate 23 is changed according to the state of the change (S106). Note that the control device 90 determines whether or not the transport speed of the combustion grate 22 and the post-combustion grate 23 need to be changed and the amount to be changed. It is preferable to determine based on also.

  Next, the control device 90 adjusts at least one of the first damper 81 to the fifth damper 85 in accordance with the state of the change in the property of the waste that causes the change in the transport speed of the dry grate 21. Then, the supply amounts of the primary combustion gas and the secondary combustion gas are adjusted (S107). Conventionally, the supply amounts of the primary combustion gas and the secondary combustion gas are adjusted using, for example, 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 the other detection data, the primary combustion gas and the primary combustion gas are determined based on the moving direction of the flame combustion start position (moving upstream or downstream). Adjust the supply amount of secondary combustion gas. Here, when the flame burning start position is moved to the upstream side and the transport speed of each grate is increased, generally the amount of generated pyrolysis gas is increased although it depends on the property of the waste. At the same time, primary combustion gas (including unburned gas such as CO) generated by performing primary combustion increases. Therefore, it is necessary to increase the supply amounts of the primary combustion gas and the secondary combustion gas. On the other hand, when the flame combustion start position is moved downstream and the transport speed of each grate is reduced, generally the amount of generated pyrolysis gas is reduced although it depends on the properties of the waste. At the same time, the amount of primary combustion gas generated by performing the primary combustion is reduced. Therefore, it is necessary to reduce the supply amounts of the primary combustion gas and the secondary combustion gas.

  In addition, since there is a possibility that the property of the waste is constantly changed, the control device 90 performs the processing of step S101 and thereafter again after the processing of step S107. As a result, even if the properties of the waste change, the progress of the drying and burning of the waste can be corrected so as to be appropriate. Combustion can be maintained.

  As described above, the incinerator 10 of the present embodiment includes a grate (a dry grate 21, a combustion grate 22, and a post-combustion grate) divided into a drying unit 11, a combustion unit 12, and a post-combustion unit 13. Grate 23), which is operated intermittently with the waste loaded thereon, thereby transporting the waste toward the furnace outlet and supplying primary combustion gas through the grate. . In the in-furnace situation determination method of the present embodiment, a process including an image acquisition step and a calculation step is performed. In the image acquisition step, at least the appearance of the waste placed on the boundary between the drying unit 11 and the combustion unit 12 is obtained from the window 11b provided on the side wall 11a formed at the end of the drying unit 11 in the furnace width direction. Get the video including. In the calculation step, the flame combustion start position is specified based on the image acquired in the image acquisition step, and it is calculated whether the flame combustion start position is moving upstream in the transport direction or downstream in the transport direction.

  In the grate-type incinerator 10, it is important to keep the burn-off point (end position of flame combustion), which is the boundary between combustion and post-combustion, in an appropriate range in order to realize stable combustion. It has been discovered by the inventor of the present application that the main reason that the position of the burn-out point is out of the appropriate range is that the difference between the assumed drying time and the actual drying time is caused by the difference in the properties of the waste. Was. Here, since the moving direction of the flame combustion start position corresponds to the tendency of the difference between the assumed drying time and the actual drying time (that is, the appropriateness of the progress of the drying and burning of the waste), the burn-off point is appropriately set. It can be handled as information necessary to keep it within a reasonable range.

  In addition, since the side wall of the combustion unit 12 becomes extremely hot and it is difficult to install the window unit and the imaging device, the window unit 11b is provided on the side wall 11a of the drying unit 11 to specify the flame combustion start position. Images can be properly acquired. Furthermore, since the side wall 11a is unlikely to be affected by pyrolysis gas, combustion gas, and the like generated in the furnace unlike the ceiling wall or the like, an image for specifying the flame combustion start position can be appropriately acquired.

  Further, in the combustion control method of the present embodiment, when it is detected that the flame combustion start position has moved to the upstream side, control is performed to increase the transport speed of the waste by the dry grate 21. Further, when it is detected that the flame combustion start position has moved to the downstream side, control is performed to reduce the conveyance speed of the waste by the dry grate 21.

  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 burn-off point can be set within an appropriate range, 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 property of the waste, which is the cause of the change in the transport speed of the dry grate 21. The conveying speed of the grate 22 and the post-combustion grate 23 is changed.

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

  In the combustion control method according to the present embodiment, at least one of the drying unit 11, the combustion unit 12, and the post-combustion unit 13 is determined based on whether the flame combustion start position is moving upstream or downstream. The supply amount of the primary combustion gas supplied to the fuel cell is adjusted.

  This makes it possible to correct the excess or deficiency of the primary combustion gas resulting from the change in the transport speed of the waste, so that drying, combustion, and post-combustion can be performed more appropriately.

  Further, in the incinerator 10 of the present embodiment, the primary combustion performed in the drying unit 11, the combustion unit 12, and the post-combustion unit 13, and the secondary combustion that burns the primary combustion gas including the unburned gas generated in the primary combustion. And combustion. In the combustion control method of this embodiment, the supply amount of the secondary combustion gas is adjusted based on whether the flame combustion start position is moving upstream or downstream.

  This makes it possible to estimate the progress of the primary combustion (ie, the amount of primary combustion gas, etc.) based on the moving direction of the flame combustion start position, and adjusts the supply amount of the secondary combustion gas accordingly. Thus, the unburned gas contained in the primary combustion gas can be sufficiently burned in the secondary combustion.

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

  In the above embodiment, only the imaging device 95 for acquiring the image including the flame combustion start position is provided as the device for acquiring the image in the furnace. Instead of this, a conventional imaging device (specifically, an imaging device that captures an area on the downstream side of the center of the combustion grate 22 in the transport direction) may be further provided.

  In the above embodiment, the process of changing the transport speed of the dry grate 21 and the supply amounts of the primary combustion gas and the secondary combustion gas based on the moving direction of the flame combustion start position is performed. A process of changing the transport speed of the dry grate 21 and the supply amounts of the primary combustion gas and the secondary combustion gas may be performed using the moving speed in addition to the moving direction.

  In the above-described embodiment, the detection data used in the combustion control includes 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. The combustion control may be performed by omitting at least one detection data, or may be performed by adding detection data different from the above. As other detection data, for example, a boiler evaporation amount accompanying heat recovery from exhaust gas, or a water spray cooling water amount when cooling by water spray can be used.

10 incinerators (waste incinerators)
DESCRIPTION OF SYMBOLS 11 Drying part 11a Side wall 11b Window part 12 Burning part 13 Post-burning part 20 Conveying part 21 Dry grate 22 Burning grate 23 Post-burning grate 90 Control device 95 Imaging device

Claims (4)

It is composed of a grate divided into a drying section, a combustion section, and a post-combustion section, and intermittently operates while the waste is placed, thereby transporting the waste toward the furnace outlet and For a waste incinerator that supplies primary combustion gas through a grate,
An image for acquiring an image including at least an appearance of the waste placed on a boundary between the drying unit and the combustion unit from a window provided on a side wall formed at an end of the drying unit in a furnace width direction. The acquisition process,
A calculation step of identifying the flame combustion start position based on the image acquired in the image acquisition step, and calculating whether the flame combustion start position is moving upstream in the transport direction or downstream in the transport direction,
Control process;
There line processing including,
In the waste incinerator, the primary combustion performed in the drying section, the combustion section, and the post-combustion section, and the secondary combustion for burning the primary combustion gas including the unburned gas generated in the primary combustion, Done,
In the control step,
If it is calculated that the flame combustion start position is moving upstream in the transport direction, perform control to increase the transport speed of the waste by the grate of the drying unit,
If it is calculated that the flame combustion start position is moving downstream in the transport direction, perform control to reduce the transport speed of the waste by the grate of the drying unit,
A combustion control method comprising: adjusting a supply amount of a secondary combustion gas based on whether a flame combustion start position is moving upstream in a transport direction or downstream in a transport direction . The combustion control method according to claim 1 , wherein
Wherein in the control step, the thereby change the conveying speed of the grate of the drying section, according to the state of change of the nature of the which is the fire causes the change of the conveying speed of the grating of the drying unit the waste, the A combustion control method characterized by changing a conveying speed of the grate of the combustion part and the conveyance speed of the grate of the post-combustion part. The combustion control method according to claim 1 or 2 ,
In the control step, based on whether the flame combustion start position is moving upstream in the transport direction or downstream in the transport direction, at least one of the drying section, the combustion section, and the post-combustion section. A combustion control method comprising adjusting a supply amount of a supplied primary combustion gas. A transport section that is composed of a grate divided into a drying section, a combustion section, and a post-combustion section, and that intermittently operates in a state where the waste is placed, thereby transporting the waste toward a furnace outlet. When,
Is provided below each of said grate, and wind boxes in which the primary combustion gas to be supplied to the waste through the grate is supplied,
Imaging to acquire an image including at least the appearance of the waste placed on the boundary between the drying unit and the combustion unit from a window provided on a side wall formed at an end of the drying unit in the furnace width direction. Equipment and
A control device that specifies the flame combustion start position based on the image obtained by the imaging device, and calculates whether the flame combustion start position is moving upstream in the transport direction or moving downstream in the transport direction,
With
In the furnace, the primary combustion performed in the drying unit, the combustion unit, and the post-combustion unit, and the secondary combustion for burning the primary combustion gas including the unburned gas generated in the primary combustion is performed.
The control device includes:
If it is calculated that the flame combustion start position is moving upstream in the transport direction, perform control to increase the transport speed of the waste by the grate of the drying unit,
If it is calculated that the flame combustion start position is moving downstream in the transport direction, perform control to reduce the transport speed of the waste by the grate of the drying unit,
A waste incinerator characterized in that the supply amount of secondary combustion gas is adjusted based on whether the flame combustion start position is moving upstream in the transport direction or downstream in the transport direction .

Images