Combustion equipment and control method

Abstract

The object is to provide a combustion facility capable of achieving appropriate combustion. [Solution] The combustion equipment comprises a furnace into which combustion gas flows in, and a furnace body which includes a drying stage, a combustion stage, and a post-combustion stage and which transports the materials to be incinerated while burning them, where the upstream side in the transport direction of the materials to be incinerated is referred to as the front and the downstream side in the transport direction is referred to as the rear, and the furnace body has a front ceiling section extending forward from the furnace, a rear ceiling section extending rearward from the furnace, and a rear wall extending downward from the rear end of the rear ceiling section, a first nozzle which is provided in an area in the rear ceiling section rearward of the center of the rear ceiling section in the transport direction or in the rear wall and which discharges a first combustion gas forward, a second nozzle which is provided in the rear ceiling section at a position forward of the first nozzle and which discharges a second combustion gas from the rear ceiling section towards the drying stage or combustion stage, and a control unit which controls the amount of the second combustion gas discharged by the second nozzle based on a target air ratio in the primary combustion zone, which is an area within the furnace body.

Description

[Technical field]

[0001] The present disclosure relates to combustion equipment and control methods. [Background technology]

[0002] Patent Document 1 discloses an incineration device in which the oxygen concentration in the rotary kiln is controlled to a desired oxygen concentration. Patent Document 2 discloses an incinerator that suppresses an increase in the NOx concentration in the exhaust gas discharged from the secondary combustion chamber. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5430210 Publication [Patent Document 2] Patent No. 7199305 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the incineration apparatus described in Patent Document 1 and the incinerator described in Patent Document 2, it is desired to achieve more appropriate combustion.

[0005] The present disclosure has been made to solve the above-mentioned problems, and has an object to provide a combustion facility and a control method capable of achieving appropriate combustion. [Means for solving the problem]

[0006] In order to solve the above problems, the combustion equipment according to the present disclosure includes: a furnace into which combustion gas flows; a furnace body including a drying stage, a combustion stage, and a post-combustion stage for transporting the incinerated materials while combusting them, the furnace body having a front ceiling portion extending forward from the furnace, a rear ceiling portion extending rearward from the furnace, and a rear wall extending downward from the rear end of the rear ceiling portion, where the upstream side in the transport direction of the incinerated materials is referred to as the front and the downstream side in the transport direction as the rear; a first nozzle provided in the rear ceiling portion in an area rearward of the center of the rear ceiling portion in the transport direction or on the rear wall, which ejects a first combustion gas forward; and a second nozzle provided in the rear ceiling portion at a position forward of the first nozzle, which ejects a first combustion gas from the rear ceiling portion to the drying stage. or the combustion stage; a detection unit that detects a decrease in NOx concentration in a primary combustion zone, which is an area within the furnace body; and a control unit that controls the amount of the second combustion gas discharged from the second nozzle based on a target air ratio in the primary combustion zone, wherein, when a decrease in NOx concentration in the primary combustion zone is detected by the detection unit, the control unit performs control to reduce the flow rate of the first combustion gas, and when an increase in NOx concentration in the primary combustion zone or a sign of such an increase is not detected even after control to reduce the flow rate of the first combustion gas, the control unit performs control to reduce the flow rate of the second combustion gas. The combustion equipment according to the present disclosure is a furnace into which post-combustion gas flows, and a furnace body including a drying stage, a combustion stage, and a post-combustion stage for transporting materials to be incinerated while burning them, and in which, when the upstream side in the transport direction of the materials to be incinerated is referred to as the front and the downstream side in the transport direction is referred to as the rear, the furnace body has a front ceiling section extending forward from the furnace, a rear ceiling section extending rearward from the furnace, and a rear wall extending downward from the rear end of the rear ceiling section, a first nozzle provided in the rear ceiling section in an area rearward of the center of the rear ceiling section in the transport direction or on the rear wall, and ejecting a first combustion gas forward, and a second nozzle provided in the rear ceiling section at a position forward of the first nozzle and ejecting a first combustion gas forward from the rear ceiling section. a second nozzle that discharges a second combustion gas toward the drying stage or the combustion stage; a detection unit that detects a decrease in oxygen concentration in a primary combustion zone that is a region within the furnace body; and a control unit that controls the amount of the second combustion gas discharged from the second nozzle based on a target air ratio in the primary combustion zone, wherein, when the detection unit detects a decrease in the oxygen concentration in the primary combustion zone, the control unit performs control to increase the oxygen concentration of the first combustion gas, and when an increase in the oxygen concentration in the primary combustion zone or a sign of such an increase is not detected even after the control to increase the oxygen concentration of the first combustion gas, the control unit performs control to increase the oxygen concentration of the second combustion gas. .

[0007] The combustion control method according to the present disclosure includes: A method for controlling combustion equipment, the combustion equipment comprising: a furnace into which combustion gas flows, a drying stage, a combustion stage, and a post-combustion stage; a furnace body for transporting materials to be incinerated while combusting them; a furnace body having a front ceiling portion extending forward from the furnace, a rear ceiling portion extending rearward from the furnace, and a rear wall extending downward from a rear end portion of the rear ceiling portion, where the upstream side in the transport direction of the materials to be incinerated is referred to as the front and the downstream side in the transport direction as the rear; a first nozzle provided in the rear ceiling portion in an area rearward of the center of the rear ceiling portion in the transport direction or on the rear wall, the first nozzle discharging a first combustion gas forward; and a second nozzle provided in the rear ceiling portion at a position forward of the first nozzle, the first nozzle discharging a first combustion gas forward. The furnace further comprises a second nozzle which discharges a second combustion gas from the ceiling portion toward the drying stage or the combustion stage, and a detection unit which detects a decrease in oxygen concentration in the primary combustion zone, which is an area within the furnace body, and one or more computers control the amount of the second combustion gas discharged from the second nozzle based on a target air ratio in the primary combustion zone, and when a decrease in NOx concentration in the primary combustion zone is detected, control is performed to reduce the flow rate of the first combustion gas, and when an increase in NOx concentration in the primary combustion zone or a sign of such an increase is not detected even after control to reduce the flow rate of the first combustion gas, control is performed to reduce the flow rate of the second combustion gas. The combustion control method according to the present disclosure is a control method for combustion equipment, the combustion equipment including a furnace into which combustion gas flows, a drying stage, a combustion stage, and a post-combustion stage, a furnace body that transports the incineration materials while combusting them, the furnace body having a front ceiling portion extending forward from the furnace, a rear ceiling portion extending rearward from the furnace, and a rear wall extending downward from a rear end portion of the rear ceiling portion, where the upstream side in the transport direction of the incineration materials is referred to as the front and the downstream side in the transport direction is referred to as the rear, a first nozzle that is provided in the rear ceiling portion in an area rearward of the center of the rear ceiling portion in the transport direction or on the rear wall, and that ejects a first combustion gas forward, and a second nozzle that is provided in the rear ceiling portion in front of the first nozzle. and a second nozzle disposed at a position above the drying stage or the combustion stage and discharging a second combustion gas from the rear ceiling portion toward the drying stage or the combustion stage, and a detection unit that detects a decrease in oxygen concentration in a primary combustion zone, which is a region within the furnace body, wherein one or more computers control the amount of the second combustion gas discharged from the second nozzle based on a target air ratio in the primary combustion zone, and when the detection unit detects a decrease in the oxygen concentration in the primary combustion zone, perform control to increase the oxygen concentration of the first combustion gas, and when an increase in the oxygen concentration in the primary combustion zone or a sign of such an increase is not detected even after the above control, perform control to increase the oxygen concentration of the second combustion gas. Effect of the Invention

[0008] According to the combustion equipment system and the combustion control method of the present disclosure, appropriate combustion can be achieved. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing an example of the configuration of a combustion facility according to a first embodiment of the present disclosure. [Diagram 2] 3 is a diagram showing an example of a configuration of a storage section according to the first embodiment of the present disclosure. FIG. [Diagram 3] FIG. 1 is a diagram showing an example of the configuration of a combustion facility according to a first embodiment of the present disclosure. [Figure 4] FIG. 2 is a diagram showing an example of a gas flow in a combustion facility that does not have a second EGR nozzle. [Diagram 5] FIG. 2 is a diagram showing an example of a gas flow in a combustion facility in which a second EGR nozzle according to the first embodiment of the present disclosure is present. [Figure 6] FIG. 4 is a diagram showing an example of a relationship between the angle at which the second EGR nozzle discharges gas and combustion according to the first embodiment of the present disclosure. [Figure 7] FIG. 4 is a diagram showing an example of a relationship between a position at which the second EGR nozzle discharges gas and combustion according to the first embodiment of the present disclosure. [Figure 8] FIG. 4 is a diagram showing an example of gas flow velocity in a combustion facility that does not have a second EGR nozzle. [Figure 9] FIG. 2 is a diagram showing an example of gas flow velocity in a combustion apparatus 1 in which a second EGR nozzle according to the first embodiment of the present disclosure is present. [Figure 10] FIG. 1 is a diagram showing an example of SRg in a combustion facility that does not have a second EGR nozzle. [Figure 11] FIG. 2 is a diagram showing an example of SRg in a combustion equipment 1 in which a second EGR nozzle according to a first embodiment of the present disclosure is present. [Figure 12] FIG. 4 is a diagram showing an example of NOx concentration distribution in a combustion facility that does not have a second EGR nozzle. [Figure 13]FIG. 2 is a diagram showing an example of NOx concentration distribution in a combustion apparatus 1 in which a second EGR nozzle according to the first embodiment of the present disclosure is present. [Figure 14] FIG. 2 is a diagram showing an example of installation positions of a first EGR nozzle and a second EGR nozzle in the first embodiment of the present disclosure. [Figure 15] FIG. 2 is a diagram illustrating an example of a gas flow around the EGR nozzle in the first embodiment of the present disclosure. [Figure 16] FIG. 4 is a diagram showing a first example of a flow of gas discharged from a first EGR nozzle due to gas discharged from a second EGR nozzle according to the first embodiment of the present disclosure. [Figure 17] FIG. 4 is a diagram showing a second example of a flow of gas discharged from the first EGR nozzle due to gas discharged from the second EGR nozzle according to the first embodiment of the present disclosure. [Figure 18] FIG. 4 is a diagram illustrating an example of a relationship between the flow of gas discharged from a second EGR nozzle and the flow of gas discharged from a first EGR nozzle according to the first embodiment of the present disclosure. [Figure 19] FIG. 11 is a diagram showing an example of a process flow for controlling EGR mixed in accordance with O2 in a combustion equipment according to a second embodiment of the present disclosure. [Figure 20] FIG. 11 is a diagram showing an example of a process flow in which the combustion equipment according to the second embodiment of the present disclosure controls EGR in accordance with O2 and a stoker speed. [Figure 21] FIG. 11 is a diagram showing an image of processing performed by a control unit 130 according to a second embodiment of the present disclosure. [Figure 22] FIG. 2 is a hardware configuration diagram showing the configuration of a computer according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. In the following description, the same reference numerals are given to configurations having the same or similar functions. And, duplicated descriptions of those configurations may be omitted. In this disclosure, "based on XX" means "based on at least XX" and may include cases based on other elements in addition to XX. Also, "based on XX" is not limited to cases where XX is directly used, but may also include cases where XX is based on something that has been calculated or processed. In this disclosure, "XX or YY" is not limited to either one of XX and YY, but may also include both XX and YY. This also applies when there are three or more selective elements. "XX" and "YY" are any elements (for example, any information).

[0011] In this application, "obtain" is not limited to actively obtaining information by sending a transmission request, but may also include passively receiving information transmitted from another device. Also, "obtain" is not limited to directly obtaining target information (information to be obtained) from outside, but may also include generating and obtaining target information by performing calculations or processing on information obtained from outside.

[0012] In the embodiment described below, for convenience of explanation, the side where the furnace body 30 is located relative to the hopper 21 described below is defined as the "rear" and the opposite side as the "front". For convenience of explanation, the upstream side of the transport direction of the incinerated material may be referred to as the "front" and the downstream side of the transport direction as the "rear". Furthermore, the "front side" may be referred to as the "front of the furnace" and the "rear side" as the "end of the furnace". Furthermore, "left" and "right" are defined based on the direction from the hopper 21 toward the furnace body 30.

[0013] First Embodiment (Overall configuration of combustion equipment) FIG. 1 is a diagram showing an example of the configuration of a combustion facility 1 according to a first embodiment of the present disclosure. For example, the combustion facility 1 is a stoker furnace that treats municipal waste, industrial waste, biomass, or the like as incineration materials S. Note that the combustion facility 1 is not limited to a stoker furnace, and may be another type of combustion facility. For convenience of explanation, the "materials to be incinerated" may be referred to as "waste" below. For example, the combustion facility 1 includes a storage section 2 (see FIG. 2), an incinerator 3, a heat recovery boiler 4, a cooling tower 5, a dust collector 6, a flue 7, a chimney 8, and a control device 100.

[0014] The storage section 2 temporarily stores the collected incineration materials S. The incinerator 3 is a furnace that combusts the incineration materials S fed from the storage section 2 while transporting them. Exhaust gas is generated in the incinerator 3 as the incineration materials S are burned in the incinerator 3. The generated exhaust gas is sent to a heat recovery boiler 4 provided on the top of the incinerator 3. The heat recovery boiler 4 exchanges heat between the exhaust gas generated in the incinerator 3 and water to heat the water and generate steam. The exhaust gas that passes through the heat recovery boiler 4 is cooled in a temperature reducing tower 5 and then sent to a dust collector 6. After soot and dust are removed from the exhaust gas in the dust collector 6, it is discharged into the atmosphere through a flue 7 and a chimney 8.

[0015] (Storage section) First, the storage unit 2 will be described in detail. Fig. 2 is a diagram showing an example of the configuration of the storage unit 2 according to the first embodiment of the present disclosure. The storage unit 2 is a facility that temporarily stores collected incineration materials S and feeds the stored incineration materials S into the incinerator 3. For example, the storage unit 2 includes a garbage pit 11, one or more cranes 12, and a camera 13.

[0016] (Garbage pit) The waste pit 11 is provided upstream of the incinerator 3 and is a storage section in which the materials to be incinerated S are temporarily stored before being fed into the incinerator 3.

[0017] (crane) The crane 12 is provided on the ceiling of the storage section 2. The crane 12 is driven based on a control instruction from the control section 130, which will be described later. For example, when new incineration materials S are carried into the garbage pit 11 from a compactor truck, the crane 12 moves the carried-in incineration materials S to the storage section 2 based on a control instruction from the control section 130.

[0018] In addition, when the crane 12 receives a control instruction from the control unit 130 to dump the material to be incinerated S stored in the garbage pit 11 into the hopper 21 of the incinerator 3, it moves to the area R in the garbage pit 11 where the material to be incinerated S can be grasped, grasps the material to be incinerated S in the grasping area R, and dumps the grasped material to be incinerated S into the hopper 21.

[0019] (Incinerator) Next, returning to Fig. 1, a detailed description will be given of the incinerator 3. The incinerator 3 has, for example, a supply mechanism 20, a furnace body 30, a stoker 40, a discharge chute 43, a plurality of wind boxes 50, a furnace 60, a blower mechanism 70, a first EGR nozzle 91 (an example of a first nozzle), and a second EGR nozzle 93 (an example of a second nozzle).

[0020] (supply mechanism) The supply mechanism 20 is a mechanism for temporarily storing the incineration material S transported by the crane 12 and sequentially supplying the material S to a treatment space V of the furnace body 30, which will be described later. The supply mechanism 20 includes, for example, a hopper 21, a feeder 22, an extrusion device 23 (see FIG. 3), a moisture meter 24, and a water sprinkler 25.

[0021] (Hopper) The hopper 21 is a storage section provided to supply the materials to be incinerated S to the inside of the furnace body 30. The hopper 21 has an inlet section for feeding the materials to be incinerated S, and an outlet section that leads to a treatment space V of the furnace body 30, which will be described later. The materials to be incinerated S carried by the crane 12 are fed into the hopper 21.

[0022] (feeder) The feeder 22 is provided at the bottom of the hopper 21. The feeder 22 is formed, for example, in a plate shape that fits along the bottom of the hopper 21. The feeder 22 is driven by the pushing device 23 and can move back and forth along a direction from the hopper 21 toward the treatment space V of the furnace body 30. The feeder 22 is driven by the pushing device 23 and pushes out the material to be incinerated S accumulated inside the hopper 21 toward the treatment space V of the furnace body 30.

[0023] (Moisture meter) The moisture meter 24 is a meter that detects information (e.g., moisture percentage or moisture amount) related to the moisture content of the incineration target S that is put into the hopper 21. For example, the moisture meter 24 has an irradiation unit and a detection unit provided in the hopper 21, and an analysis unit. The irradiation unit irradiates electromagnetic waves of a predetermined frequency band to the incineration target S that is piled up in the hopper 21. The detection unit receives the electromagnetic waves irradiated from the irradiation unit and transmitted through the incineration target S or reflected by the incineration target S. The analysis unit stores in advance, for example, correlation information indicating the relationship between the characteristic change of the electromagnetic wave (e.g., change in amplitude or change in phase) and the moisture percentage. The analysis unit detects the moisture percentage of the incineration target S based on the characteristic change of the electromagnetic wave between the irradiation unit and the detection unit and the above correlation information. The moisture meter 24 may detect the moisture amount of the incineration target S based on the above moisture percentage and the weight of the incineration target S that is put into the hopper 21.

[0024] (Water sprinkler system) The water sprinkler 25 is a device that adjusts the moisture content of the incineration target S by sprinkling water on the incineration target S. The water sprinkler 25 is provided, for example, in the hopper 21. When adjusting the moisture content of the incineration target S, the water sprinkler 25 sprinkles water on the incineration target S in the hopper 21 based on a control instruction from the control unit 130 described later.

[0025] (furnace body) The furnace body 30 is provided adjacent to the hopper 21, and is a facility for combusting the incineration target S while transporting it. Hereinafter, the transport direction of the incineration target S in the combustion facility 1 is referred to as the "transport direction D." The transport direction D may also be referred to as the "depth direction."

[0026] The furnace body 30 has a drying stage 30a, a combustion stage 30b, and a post-combustion stage 30c in this order from the upstream side to the downstream side in the conveying direction D. The furnace body 30 conveys the incineration material S from the upstream side to the downstream side while burning it. The drying stage 30a is located upstream of the combustion stage 30b and the post-combustion stage 30c, and is a region in which the incineration material S supplied from the hopper 21 is dried prior to combustion on the stoker 40. The combustion stage 30b and the post-combustion stage 30c are regions in which the incineration material S in a dried state after passing through the drying stage 30a is burned on the stoker 40. In the combustion stage 30b, diffusion combustion occurs due to pyrolysis gas generated from the incineration material S, and a flame F is generated. In the post-combustion stage 30c, fixed carbon combustion occurs after diffusion combustion of the incineration material S, so no flame F is generated.

[0027] (furnace temperature sensor) The furnace body 30 has, for example, an in-furnace temperature sensor 31. The in-furnace temperature sensor 31 is, for example, a thermocouple, and detects the temperature inside the furnace body 30. In this embodiment, only one in-furnace temperature sensor 31 is provided as a temperature sensor that detects the temperature inside the furnace body 30. The temperature inside the furnace body 30 is an example of the "temperature inside the incinerator." The in-furnace temperature sensor 31 may be provided in the furnace 60 or another location instead of / in addition to the furnace body 30. The temperature detected in the furnace 60 or another location is another example of the "temperature inside the incinerator."

[0028] (camera) The furnace body 30 has, for example, a visible light camera 32 and an infrared camera 33. The visible light camera 32 and the infrared camera 33 photograph the inside of the furnace body 30. For example, the visible light camera 32 and the infrared camera 33 are provided at the downstream end (hereinafter referred to as the "furnace bottom") of the furnace body 30 in the conveying direction D, and photograph the area from the furnace bottom to the upstream side in the conveying direction D.

[0029] The visible light camera 32, for example, captures an image of the flame F. The infrared camera 33, for example, captures an image of the incineration material S (garbage layer) that is piled up on the drying stage 30a of the furnace body 30 through the flame F. The infrared camera 33 may also capture an image of the outlet of the hopper 21 instead of / in addition to the incineration material S that is piled up on the drying stage 30a. That is, the infrared camera 33 may capture an image including the incineration material S that is piled up on the feeder 22 at the outlet of the hopper 21 (an image showing the piled up state of the incineration material S). The imaging results of the visible light camera 32 and the infrared camera 33 are transmitted to the control device 100. The imaging results of the visible light camera 32 or the infrared camera 33 are an example of an "image captured inside the incineration furnace."

[0030] The infrared camera 33 may be composed of a plurality of infrared cameras arranged in a stereo system, for example. The visible light camera 32 and the infrared camera 33 may be provided at another position (such as the left or right wall of the furnace body 30) instead of at the bottom of the furnace body 30. Either or both of the visible light camera 32 and the infrared camera 33 may be omitted.

[0031] (Stalker) The stoker 40 includes a plurality of grates 41 and a grate drive device 42 (see FIG. 3). The plurality of grates 41 form a stoker surface 40a, which is the bottom surface of the furnace body 30. The incineration material S is supplied in layers to the stoker surface 40a by the supply mechanism 20. The stoker surface 40a is provided across the drying stage 30a, the combustion stage 30b, and the post-combustion stage 30c described above. The plurality of grates 41 include a fixed grate and a movable grate. The fixed grate is fixed to the upper surface of the wind box 50 described later. The movable grate moves back and forth at a constant speed along the transport direction D, stirring and mixing the incineration material S on the movable grate and the fixed grate (on the stoker surface 40a) to transport it downstream.

[0032] (Discharge chute) The discharge chute 43 is a device that drops the incineration material S that has been burned and turned into ash to an ash pusher located below the furnace body 30. The discharge chute 43 is provided at the bottom of the furnace body 30. The wall on the rear side of the discharge chute 43 is the rear wall 59 described later.

[0033] (Wind box) The multiple wind boxes 50 are provided below the stoker 40 and supply primary air for combustion to the inside of the furnace body 30 through the stoker 40. The primary air is an example of "combustion air". In this embodiment, the multiple wind boxes 50 are arranged in a line in the conveying direction D corresponding to, for example, the multiple fire grates 41. Each wind box 50 is provided with a wind box pressure sensor 51 that detects the pressure inside the wind box 50. The pressure inside the wind box 50 corresponds to the pressure of the primary air supplied from the wind box 50 to the inside of the furnace body 30. The detection result of each wind box pressure sensor 51 and / or a set of detection results of the multiple wind box pressure sensors 51 is an example of "information regarding the supply of combustion air".

[0034] (furnace) The furnace 60 extends upward from the upper part of the furnace body 30. The furnace 60 is disposed above the grate 41, and the gas after combustion flows into the furnace 60. That is, the exhaust gas generated by the combustion of the incineration material S in the furnace body 30 flows through the furnace 60 to the heat recovery boiler 4. The furnace 60 includes a front wall 60a located at the front side of the space through which the exhaust gas flows, and a rear wall 60b located at the rear side of the space through which the exhaust gas flows. The front wall 60a and the rear wall 60b each extend vertically, for example. When the upstream side of the transport direction of the incineration material S is referred to as the front, and the downstream side of the transport direction is referred to as the rear, the furnace 60 has a front ceiling portion 55 extending forward from the furnace 60, a rear ceiling portion 57 extending rearward from the furnace 60, and a rear wall 59 extending downward from the rear end of the rear ceiling portion 57.

[0035] (Blower mechanism) The blower mechanism 70 supplies combustion air to the inside of the furnace body 30 and the furnace 60. The blower mechanism 70 has, for example, a blower 71, a primary air line 72, an air preheater 73, a secondary air line 74, a damper 75, and an air flow sensor 76.

[0036] The blower 71 is a forced draft blower that pressurizes and sends combustion air to the inside of the furnace body 30 and the furnace 60. The blower 71 includes, for example, a first blower 71A and a second blower 71B. The first blower 71A pressurizes and sends primary air for combustion to the inside of the furnace body 30 (for example, the treatment space V) through the primary air line 72 and the multiple wind boxes 50. The second blower 71B pressurizes and sends secondary air for combustion to the inside of the furnace 60 through the secondary air line 74. The secondary air is another example of "combustion air".

[0037] The primary air line 72 connects the first blower 71A and the multiple wind boxes 50. One or more (for example, multiple) primary air dampers 75A are provided in the middle of the primary air line 72. In this embodiment, the multiple primary air dampers 75A are provided in one-to-one correspondence with the multiple wind boxes 50. The primary air damper 75A changes the flow rate of primary air flowing from the primary air line 72 into the wind box 50 to which the primary air damper 75A corresponds, depending on the opening degree of the primary air damper 75A. In other words, the distribution amount of primary air in the multiple wind boxes 50 (from which wind box 50 primary air is preferentially supplied into the furnace body 30) is changed depending on the opening degree of the multiple primary air dampers 75A. The opening degree of each primary air damper 75A and / or the set of the opening degrees of the multiple primary air dampers 75A is another example of "information regarding the supply of combustion air".

[0038] The air preheater 73 is a heat exchanger that preheats the primary air pressure-fed from the first blower 71A. For example, the air preheater 73 is provided midway along the primary air line 72. The air preheater 73 has a preheat temperature sensor 73a that detects the temperature of the preheated primary air. The detection result of the preheat temperature sensor 73a is another example of "information regarding the temperature of the combustion air."

[0039] The secondary air line 74 connects the second blower 71B and the furnace 60. In this embodiment, the secondary air line 74 has a first supply port 74a and a second supply port 74b. The first supply port 74a opens to the front wall 60a of the furnace 60 and supplies secondary air from the front wall 60a of the furnace 60 to the space (exhaust gas flow path) within the furnace 60. On the other hand, the second supply port 74b opens to the rear wall 60b of the furnace 60 and supplies secondary air from the rear wall 60b of the furnace 60 to the space (exhaust gas flow path) within the furnace 60.

[0040] One or more (e.g., a plurality of) secondary air dampers 75B are provided in the middle of the secondary air line 74. In this embodiment, the plurality of secondary air dampers 75B are provided in one-to-one correspondence with the plurality of supply ports (e.g., supply ports 74a, 74b) provided in the furnace 60. The secondary air damper 75B changes the distribution amount of secondary air (from which supply port secondary air is preferentially supplied into the furnace 60) in the plurality of supply ports (e.g., supply ports 74a, 74b) depending on the opening degree of the secondary air damper 75B. The opening degree of each secondary air damper 75B and / or the set of the opening degrees of the plurality of secondary air dampers 75B is another example of "information regarding the supply of combustion air". For convenience of explanation, the primary air damper 75A and the secondary air damper 75B will be collectively referred to as "damper 75" below.

[0041] The air flow sensor 76 detects the flow rate of the combustion air supplied to the inside of the furnace body 30 and the furnace 60. The air flow sensor 76 includes, for example, a first air flow sensor 76A and a second air flow sensor 76B. The first air flow sensor 76A is provided in the middle of the primary air line 72 and detects the flow rate of the primary air supplied through the primary air line 72. The second air flow sensor 76B is provided in the middle of the secondary air line 74 and detects the flow rate of the secondary air supplied through the secondary air line 74. The detection results of the first air flow sensor 76A and the second air flow sensor 76B are another example of "information regarding the supply of combustion air".

[0042] (Gas sensor) Next, the gas sensor 81 will be described. The gas sensor 81 is a sensor that detects components in exhaust gas. The gas sensor 81 can detect, for example, the oxygen concentration (hereinafter referred to as "O2 concentration"), carbon monoxide concentration (hereinafter referred to as "CO concentration") (unburned fuel), carbon dioxide concentration (hereinafter referred to as "CO2 concentration"), or NOx concentration, and the air ratio in the primary combustion region contained in the exhaust gas. The gas sensor 81 is provided, for example, in the flue 7, but may also be provided inside the chimney 8 or in another location (for example, a location where gas after combustion can be detected). The detection result of the gas sensor 81 is an example of "information regarding components in exhaust gas".

[0043] The first EGR nozzle 91 is provided in an area of ​​the rear ceiling portion 57 rearward of the center of the rear ceiling portion 57 in the transport direction of the incineration material S, or in the rear wall 59 extending downward from the rear end portion of the rear ceiling portion 57. The first EGR nozzle 91 discharges EGR (an example of a first combustion gas), air, or EGR (an example of a first combustion gas) mixed with air forward.

[0044] When the first EGR nozzle 91 is provided on the rear wall 59 extending downward from the rear end of the rear ceiling portion 57, the first EGR nozzle 91 may discharge EGR (an example of the first combustion gas), air, or EGR (an example of the first combustion gas) mixed with air in a direction that forms a wall jet along the rear ceiling portion 57. For example, the horizontal distance between the rear end and the front end of the rear ceiling portion 57 is "X", the vertical distance between the front end and the center of the opening of the first EGR nozzle 91 is "H", the angle between the rear ceiling portion 57 and the horizontal plane is "α", and the angle between the center line O of the first EGR nozzle 91 and the horizontal plane is "β". In this case, the second EGR nozzle 93 may be disposed at the bottom of the furnace so as to satisfy the following formula (I).

[0045]

number

[0046] The horizontal distance here means a two-dimensional geometric distance in the horizontal direction. The vertical distance means a one-dimensional geometric distance in the vertical direction. In addition, "atan((H / X)+tan(α))-β" on the left side of formula (I) is greater than 0. The gas discharged from the first EGR nozzle 91 becomes a wall-surface jet, which facilitates mixing.

[0047] The second EGR nozzle 93 is provided at a position in front of the first EGR nozzle 91 in the rear ceiling portion 57. The second EGR nozzle 93 discharges EGR (an example of a second combustion gas), air, or EGR mixed with air (an example of a second combustion gas) from the rear ceiling portion 57 toward the drying stage 30a or the combustion stage 30b. The second EGR nozzle 93 includes an angle adjustment mechanism 97 that can change the direction in which the EGR (an example of a second combustion gas), air, or EGR mixed with air (an example of a second combustion gas) is discharged. An example of the angle adjustment mechanism 97 is a tilt mechanism.

[0048] For example, the second EGR nozzle 93 is provided in a region of the rear ceiling portion 57 that is forward of the center of the rear ceiling portion 57 in the transport direction of the incineration materials S. More specifically, for example, if the rear ceiling portion 57 is virtually divided into four regions in the transport direction of the incineration materials S, the second EGR nozzle 93 is provided in the forwardmost region of the four divided regions. The reason why it is preferable to provide the second EGR nozzle 93 in such a position will be described later.

[0049] Also, for example, when the horizontal direction forward is set to 0°, the second EGR nozzle 93 discharges EGR (an example of the second combustion gas), air, or EGR (an example of the second combustion gas) mixed with air in a direction included in an angle range of 60° or more and 90° or less with respect to the horizontal direction. The reason why it is preferable for the second EGR nozzle 93 to discharge gas at such an angle will be described later.

[0050] Here, an advantage of the combustion equipment 1 having the second EGR nozzle 93 will be described over combustion equipment not having the second EGR nozzle 93. Fig. 4 is a diagram showing an example of a gas flow in the combustion equipment not having the second EGR nozzle 93. Fig. 5 is a diagram showing an example of a gas flow in the combustion equipment 1 having the second EGR nozzle 93 according to the first embodiment of the present disclosure.

[0051] The dashed line A in Fig. 4 shows an example of the flow of EGR (an example of a first combustion gas) discharged from the first EGR nozzle 91, air, or EGR mixed with air (an example of a first combustion gas). The dashed line B in Fig. 4 shows an example of the flow of volatile matter gas from combustion by primary air injected from below the combustion stage 30b. In this case, the gas discharged from the first EGR nozzle 91 is not sufficiently mixed with the volatile matter gas, and as shown in Fig. 4, in the case of a combustion equipment without the second EGR nozzle 93, both the gas discharged from the first EGR nozzle 91 and the volatile matter gas from combustion by primary air flow toward the furnace 60 along the space in the furnace body 30.

[0052] The dashed line A' shown in FIG. 5 shows an example of the flow of EGR (an example of a first combustion gas), air, or EGR mixed with air (an example of a first combustion gas) discharged from the first EGR nozzle 91. The dashed line B' shown in FIG. 5 shows an example of the flow of volatile matter of combustion by primary air injected from below the combustion stage 30b. The dashed line C shown in FIG. 5 shows an example of the flow of EGR (an example of a second combustion gas), air, or EGR mixed with air (an example of a second combustion gas) discharged from the second EGR nozzle 93. The dashed line D shown in FIG. 5 shows an example of the flow of dried air injected from below the drying stage 30a. As shown in FIG. 5, the gas flow A shown in FIG. 4 is pushed downward by the gas flow C discharged from the second EGR nozzle 93, and the gas discharged from the first EGR nozzle 91 changes to the gas flow A' shown in FIG. 5. The gas flow B shown in FIG. 4 is pushed downward by the gas flow A' shown in FIG. 5, and changes to the gas flow B' shown in FIG. 5. That is, when the second EGR nozzle 93 discharges EGR (an example of the second combustion gas), air, or EGR mixed with air (an example of the second combustion gas) in a direction included in the angle range of 60° or more and 90° or less with respect to the horizontal direction when the horizontal direction is set at 0°, the volatile gas of the combustion by the primary air is pushed downward, and the time of staying in the furnace body 30 is extended. As a result, the mixing of the volatile gas of the combustion by the primary air and the gas discharged from the first EGR nozzle 91 and the second EGR nozzle 93 is further promoted. In other words, the combustion of the incineration material S is promoted. In addition, the gas of the flow A' and the flow B' and the gas C suppress the dry air D from flowing to the end of the furnace. As a result, the amount of air relative to the volatile gas can be controlled by the gas discharged from the first EGR nozzle 91 and the second EGR nozzle 93 and the air introduced from below the drying stage 30a, the combustion stage 30b, and the post-combustion stage 30c. In other words, the combustion of the materials to be incinerated S in the combustion stage 30b can be controlled.

[0053] FIG. 6 is a diagram showing an example of the relationship between the angle at which the second EGR nozzle 93 discharges gas and combustion according to the first embodiment of the present disclosure. The horizontal axis in FIG. 6 indicates the angle at which the second EGR nozzle 93 discharges gas when the horizontal forward direction is set to 0°. The left vertical axis in FIG. 6 indicates the NOx concentration. The right vertical axis in FIG. 6 indicates the CO concentration. Note that the CO concentration on the right vertical axis is a relative value with the CO concentration when no gas is discharged by the second EGR nozzle 93 set to 1. From FIG. 6, it can be seen that the NOx concentration is reduced when the angle at which the second EGR nozzle 93 discharges gas is 60° or more and 90° or less. Note that there is a trade-off between the NOx concentration and the CO concentration. Therefore, in practice, an appropriate concentration is determined by the balance between the NOx concentration and the CO concentration.

[0054] FIG. 7 is a diagram showing an example of the relationship between the position at which the second EGR nozzle 93 discharges gas and combustion according to the first embodiment of the present disclosure. The horizontal axis in FIG. 7 indicates the position at which the second EGR nozzle 93 discharges gas, with the position at the front end of the drying stage 30a being 0 and the position at the rear end of the drying stage 30a being 1. The left vertical axis in FIG. 7 indicates the NOx concentration. The right vertical axis in FIG. 7 indicates the CO concentration. The CO concentration on the right vertical axis is a relative value with the CO concentration when no gas is discharged by the second EGR nozzle 93 being 1. From FIG. 7, it can be seen that the NOx concentration is lowest when the position at which the second EGR nozzle 93 discharges gas is in the range of 0 to about 0.25 (i.e., when the rear ceiling portion 57 is virtually divided into four in the conveying direction of the incineration material S and the second EGR nozzle 93 discharges gas in the most forward region of the four divided regions). Also, from FIG. 7, it can be seen that the NOx concentration begins to increase significantly when the position at which the second EGR nozzle 93 discharges gas exceeds a position of approximately 0.25 (i.e., when the position at which the second EGR nozzle 93 discharges gas in the rear ceiling portion 57 exceeds approximately 0.25). Therefore, it is desirable to provide the second EGR nozzle 93 in an area within half the front side of the rear ceiling portion 57 (if possible, within a quarter of the area). This is in order to increase the residence time in the furnace end space, which has an ideal air ratio distribution for NOx reduction. In addition, the second EGR nozzle 93 provided near the front end of the rear ceiling 57 pushes the volatile matter to the end of the furnace and the air on the front side of the furnace to the secondary combustion area, which has the effect of promoting the formation of the expected air ratio distribution in the end-of-furnace space (the effect of preventing the end-of-furnace air ratio from being left to chance). Furthermore, in order to form an ideal air ratio distribution for NOx reduction in the end-of-furnace space, it is necessary to set air ratio targets for the gases injected from the first EGR nozzle 91 and the second EGR nozzle 93, and to control the gas flow rates individually.

[0055] FIG. 8 is a diagram showing an example of the flow velocity of gas in a combustion equipment in which the second EGR nozzle 93 is not present. FIG. 9 is a diagram showing an example of the flow velocity of gas in a combustion equipment 1 in which the second EGR nozzle 93 according to the first embodiment of the present disclosure is present. In FIG. 8 and FIG. 9, the thickness of the arrow indicates the flow velocity. In addition, in FIG. 8 and FIG. 9, the direction of the arrow indicates the direction of the gas flow. In addition, the part A shown in FIG. 9 is located between the drying stage 30a and the end of the furnace, and indicates a region where the flow velocity is almost 0. This region A shows that in the combustion equipment 1 in which the second EGR nozzle 93 is present, the dry air does not flow to the end of the furnace. On the other hand, in the combustion equipment in which the second EGR nozzle 93 shown in FIG. 8 is not present, the region A shown in FIG. 9 does not exist. In other words, in the combustion equipment in which the second EGR nozzle 93 is not present, the dry air flows to the end of the furnace.

[0056] FIG. 10 is a diagram showing an example of SRg in a combustion facility in which the second EGR nozzle 93 is not present. FIG. 9 is a diagram showing an example of SRg in a combustion facility 1 in which the second EGR nozzle 93 according to the first embodiment of the present disclosure is present. In FIG. 8 and FIG. 9, part A shows a region in which SRg is approximately 1. In addition, in FIG. 8 and FIG. 9, part B shows a region in which SRg is larger than region A. In addition, in FIG. 8 and FIG. 9, part C shows a region in which SRg is lower than region A. Note that SRg represents a local air ratio, and the closer to 1, the better the mixing of EGR and air. Compared to FIG. 8, in FIG. 9, it can be seen that region A is wider in the combustion stage 30b and the post-combustion stage 30c, that is, EGR and air are well mixed.

[0057] Fig. 12 is a diagram showing an example of NOx concentration distribution in a combustion equipment in which a second EGR nozzle 93 is not present. Fig. 13 is a diagram showing an example of NOx concentration distribution in a combustion equipment 1 in which a second EGR nozzle 93 according to the first embodiment of the present disclosure is present. In Fig. 12 and Fig. 13, the NOx concentration gradually increases in the order of part A, part B, part C, and part D. Compared to Fig. 12, Fig. 13 shows that part A, where the Nox concentration is low, is expanded due to the region in which the air ratio is approximately 1 as shown in Fig. 9.

[0058] FIG. 14 is a diagram showing an example of the installation positions of the first EGR nozzle 91 and the second EGR nozzle 93 in the first embodiment of the present disclosure. FIG. 14 is a bird's-eye view of the combustion equipment 1 seen from above. The combustion equipment 1 may be provided with a plurality of first EGR nozzles 91. In this case, the plurality of first EGR nozzles 91 include the first EGR nozzle 91 according to the first embodiment of the present disclosure, and are provided in a region of the rear ceiling portion 57 behind the center of the rear ceiling portion 57 in the conveying direction of the incineration target S, or in the rear wall 59 extending downward from the rear end portion of the rear ceiling portion 57. The plurality of first EGR nozzles 91 discharge EGR (an example of the first combustion gas), air, or EGR (an example of the first combustion gas) mixed with air toward the front. In addition, a plurality of imaginary lines are defined that respectively extend toward the front from the plurality of first EGR nozzles 91, and when viewed from above, the second EGR nozzle 93 is disposed between the plurality of imaginary lines. In this case, the curvature of the gas discharged from the second EGR nozzle 93 shown in Fig. 18 described later is reduced. In this case, the mixing of the gas can be promoted by installing the first EGR nozzle 91 so as to satisfy the above-mentioned formula (I).

[0059] 14, when a plurality of first EGR nozzles 91 and a plurality of second EGR nozzles 93 are provided, it is preferable to define a plurality of imaginary lines extending forward from the plurality of first EGR nozzles 91, and to arrange the second EGR nozzle 93 between the plurality of imaginary lines. This makes it possible to suppress interference between the gas discharged from the first EGR nozzle 91 and the gas discharged from the second EGR nozzle 93. In other words, it becomes possible to easily control the direction of the gas discharged from each of the first EGR nozzle 91 and the second EGR nozzle 93.

[0060] Fig. 15 is a diagram showing an example of the gas flow around the EGR nozzle in the first embodiment of the present disclosure. The EGR nozzles in this case are a first EGR nozzle 91 and a second EGR nozzle 93. As shown in Fig. 15, it is known that gas around the first EGR nozzle 91 and the second EGR nozzle 93, respectively, is sucked into the nozzle. In the embodiment of the present disclosure, this characteristic is utilized to provide the second EGR nozzle 93 at the front end of the rear ceiling portion 57, thereby preventing unburned gas from flowing into the secondary combustion region (i.e., the furnace 60).

[0061] FIG. 16 is a diagram showing a first example of the flow of gas discharged from the first EGR nozzle 91 by the gas discharged from the second EGR nozzle 93 according to the first embodiment of the present disclosure. FIG. 17 is a diagram showing a second example of the flow of gas discharged from the first EGR nozzle 91 by the gas discharged from the second EGR nozzle 93 according to the first embodiment of the present disclosure. In the example shown in FIG. 16, the amount of gas discharged from the second EGR nozzle 93 is larger than that in the example shown in FIG. 17. If the amount of gas discharged from the second EGR nozzle 93 is too large, ash present in the combustion stage 30b and the post-combustion stage 30c may fly up, and as a result, unnecessary ash may be mixed into the gas. In addition, if the amount of gas discharged from the second EGR nozzle 93 is too small, the gas of the volatile matter of combustion by the primary air described above is pushed downward, and the time of residence in the furnace body 30 is shortened, and the effect of the gas discharged from the second EGR nozzle 93 is reduced. In other words, it is desirable for the second EGR nozzle 93 to discharge gas so as to push the volatile gases of the combustion by the primary air as far downward as possible without causing ash to fly up.

[0062] 18 is a diagram showing an example of the relationship between the flow of gas discharged from the second EGR nozzle 93 and the flow of gas discharged from the first EGR nozzle 91 according to the first embodiment of the present disclosure. In FIG. 18, a flow velocity U0 is the flow velocity of gas discharged from the second EGR nozzle 93, and a flow velocity U1 is the flow velocity of gas discharged from the first EGR nozzle 91. As shown in FIG. 18, it can be seen that the flow of gas discharged from the second EGR nozzle 93 is determined by the relationship between the flow velocity U0 and the flow velocity U1. In other words, it can be seen that in order for the second EGR nozzle 93 to discharge gas so that the gas of the volatile matter of combustion by the primary air can be pushed as far downward as possible without causing ash to fly up, it is necessary to take into consideration the flow velocity U0 and the flow velocity U1.

[0063] (Control device) Next, the control device 100 will be described. FIG. 4 is a block diagram showing the functional configuration of the combustion equipment 1. The control device 100 performs overall control of the combustion equipment 1. For example, the control device 100 performs combustion control of the incineration material S in the furnace body 30. In this disclosure, "combustion control" broadly means control related to the combustion of the incineration material S, and means, for example, control of one or more of the supply amount of the incineration material S, the moisture content of the incineration material S, the conveying speed of the incineration material S, the flow rate and / or distribution amount of the primary air, the temperature of the primary air, the flow rate and / or distribution amount of the secondary air, and the like.

[0064] In this embodiment, the control device 100 includes, for example, an information acquisition unit 110 and a control unit 130. Devices to be controlled by the control unit 130 (hereinafter referred to as "controlled devices VD") include the crane 12, the pusher 23, the sprinkler 25, the grate driver 42, the blower 71, the air preheater 73, the damper 75, the first EGR nozzle 91, and the second EGR nozzle 93.

[0065] (Information acquisition department) The information acquisition unit 110 acquires the detection results detected by various sensors provided in the combustion equipment 1. For example, the information acquisition unit 110 acquires the detection results of the camera 13 provided in the storage unit 2, the detection results of the moisture meter 24 (information on the moisture content of the incinerated material S), the detection results of the incinerator temperature sensor 31 (information on the temperature inside the incinerator 3), the imaging results of the visible light camera 32 (information on the combustion flame seen from the end of the furnace), the imaging results of the infrared camera 33 (information on the garbage layer), the detection results of each wind box pressure sensor 51 (information on the flow rate and / or distribution amount of primary air), the detection results of the preheating temperature sensor 73a (information on the temperature of primary air (temperature of combustion air)), the detection results of the air flow sensor 76 (information on the flow rate of combustion air), and the detection results of the gas sensor 81 (information on the components in the exhaust gas). Hereinafter, these are collectively referred to as "various detection information".

[0066] The information acquisition unit 110 also acquires control information indicating the state of each device included in the controlled device VD from each device or the control unit 130. For example, the information acquisition unit 110 acquires control information indicating the gripping point of the crane 12 in the garbage pit 11, control information indicating the driving state of the feeder 22 by the extrusion device 23 (information regarding the supply amount of the incineration target material S, for example, the moving speed and / or stroke length of the feeder 22), control information indicating the driving state of the grate driving device 42 (information regarding the conveying speed of the incineration target material S), control information indicating the driving amount of the blower 71 (information regarding the supply of combustion air), control information indicating the heating amount of the air preheater 73 (information regarding the supply of primary air), and control information indicating the opening degree of the damper 75 (information regarding the supply of combustion air). Hereinafter, these are collectively referred to as "various control information".

[0067] (Control unit)

[0068] The control unit 130 controls the flow rate of the gas discharged from the first EGR nozzle 91 and the second EGR nozzle 93 to a desired flow rate. The flow rate of the gas is also controlled by controlling the flow rate of the gas. The control unit 130 controls the discharge direction of the gas from the second EGR nozzle 93, for example, by controlling the orientation of the angle adjustment mechanism 97, depending on the components contained in the gas detected by the gas sensor 81. For example, when suppressing the CO concentration, the control unit 130 controls the discharge direction of the gas to approach 60° within a range of 60° to 90° by adjusting the orientation of the angle adjustment mechanism 97. For example, when suppressing the NOx concentration, the control unit 130 controls the discharge direction of the gas to approach 90° within a range of 60° to 90° by adjusting the orientation of the angle adjustment mechanism 97. The control by the control unit 130 is such that the combustion equipment 1 in which the second EGR nozzle 93 is present is dominant over the combustion equipment in which the second EGR nozzle 93 is not present. That is, the second EGR nozzle 93 is arranged so as to obtain the effects described with reference to Figures 14 and 15, and the control unit 130 performs control so as to obtain the effects described with reference to Figures 9, 11, 13, 16, 17, and 18. Note that the flow speed of the gas discharged from the first EGR nozzle 91 and the second EGR nozzle 93 may be changed by changing the nozzle diameter.

[0069] Furthermore, the control unit 130 performs combustion control for the incinerator 3 based on values ​​related to the position or shape of the flame F derived by the flame information derivation unit 120. For example, the control unit 130 controls one or more of the supply amount of the incinerated material S, the moisture content of the incinerated material S, the transport speed of the incinerated material S, the supply amount and / or distribution amount of the primary air, the temperature of the combustion air (e.g., the temperature of the primary air), the supply amount and / or distribution amount of the secondary air, etc., based on one or more of the center of gravity G of the flame F, the burnout position PE of the flame F, or the width W in the depth direction of the flame F.

[0070] The control unit 130 also controls the extrusion device 23 to change the moving speed or stroke length of the feeder 22, thereby changing the supply amount of the incineration material S. The control unit 130 changes the moisture content of the incineration material S by performing water sprinkling using the water sprinkler 25. The control unit 130 changes the conveying speed of the incineration material S by controlling the grate drive device 42 to change the drive speed of the grate 41. The control unit 130 changes the flow rate of the primary air and / or the flow rate of the secondary air by controlling the blower 71. The control unit 130 changes the temperature of the primary air by performing heating using the air preheater 73. The control unit 130 controls the opening degree of the damper 75 to control the distribution amount of the primary air and / or the distribution amount of the secondary air.

[0071] Furthermore, the control unit 130 performs combustion control for the incinerator 3 based on the position of the center of gravity G of the flame F derived by the flame information derivation unit 120. For example, when the position of the center of gravity G of the flame F derived by the flame information derivation unit 120 differs from the planned position (planned position of the center of gravity), the control unit 130 controls one or more of the supply amount of the material S to be incinerated, the moisture content of the material S to be incinerated, the transport speed of the material S to be incinerated, the flow rate and / or distribution amount of the primary air, and the temperature of the combustion air (for example, the temperature of the primary air) so as to bring the position of the center of gravity G of the flame F closer to the planned position.

[0072] For example, when the center of gravity G of the flame F is closer to the bottom of the furnace than the planned position, the control unit 130 performs one or more of the following to dry the incineration material S upstream: reducing the supply amount of the incineration material S (for example, reducing the moving speed of the feeder 22 or shortening the stroke length), maintaining the moisture content of the incineration material S low (for example, suppressing the sprinkling by the sprinkler 25), reducing the conveying speed of the incineration material S (for example, reducing the driving speed of the grate 41), increasing the supply amount of primary air (for example, increasing the driving speed of the first blower 71A), increasing the distribution amount of primary air to the position on the front side of the furnace (for example, increasing the opening degree of the primary air damper 75A corresponding to one or more wind boxes 50 located on the front side of the furnace), and increasing the preheating temperature by the air preheater 73. On the other hand, when the center of gravity G of the flame F is closer to the front side of the furnace than the planned position, the control unit 130 performs the opposite control to the above.

[0073] The combustion equipment 1 according to the first embodiment of the present disclosure has been described above. The combustion equipment 1 includes a furnace 60 into which post-combustion gas flows, a furnace body 30 including a drying stage 30a, a combustion stage 30b, and a post-combustion stage 30c, which transports the incineration material S while combusting it, and the furnace body 30 has a front ceiling part 55 extending forward from the furnace 60, a rear ceiling part 57 extending rearward from the furnace 60, and a rear wall 59 extending downward from the rear end part of the rear ceiling part 57, where the upstream side in the transport direction of the incineration material S is referred to as the front and the downstream side in the transport direction is referred to as the rear. The furnace comprises a first EGR nozzle 91 (an example of a first nozzle) provided on the rear wall 59 and discharging a first combustion gas forward, a second EGR nozzle 93 (an example of a second nozzle) provided at a position forward of the first EGR nozzle 91 in the rear ceiling portion 57 and discharging a second combustion gas from the rear ceiling portion 57 toward the drying stage 30a or the combustion stage 30b, and a control unit 130 that controls the amount of the second combustion gas discharged by the second EGR nozzle 93 based on a target air ratio in the primary combustion zone, which is an area within the furnace body 30.

[0074] It is possible to stabilize exhaust gas components (eg, reduce NOx) by using this combustion equipment 1. In other words, it is possible to achieve appropriate combustion by using this combustion equipment 1.

[0075] The above-described process performed by the combustion equipment 1 is merely an example, and the process performed by the combustion equipment 1 is not limited to the above-described process. For example, the combustion equipment 1 may perform the process described below.

[0076] <Second embodiment> Next, a combustion equipment 1 according to a second embodiment of the present disclosure will be described. In addition to the configuration of the combustion equipment 1 according to the first embodiment, the combustion equipment 1 according to the second embodiment further includes a detection unit 95 that detects a decrease in O2 concentration inside the furnace body 30 (e.g., the treatment space V, an example of a primary combustion region). When the detection unit 95 detects a decrease in O2 concentration inside the furnace body 30, the control unit 130 according to the second embodiment performs control to increase the O2 concentration of EGR (an example of a first combustion gas), air, or EGR mixed with air (an example of a first combustion gas) discharged from the first EGR nozzle 91. Furthermore, when the control unit 130 according to the second embodiment performs control to increase the O2 concentration but does not detect an increase or signs of an increase in the O2 concentration of the EGR (an example of a first combustion gas), air, or EGR mixed with air (an example of a first combustion gas) discharged from the first EGR nozzle 91, the control unit 130 performs control to increase the O2 concentration of the EGR (an example of a second combustion gas), air, or EGR mixed with air (an example of a second combustion gas) discharged from the second EGR nozzle 93.

[0077] The detection unit 95 may detect any state (e.g., burnout of a solid layer, combustion flame) inside the furnace body 30. For example, the detection unit 95 may detect a decrease in O2 concentration inside the furnace body 30 based on an exhaust gas concentration prediction model created by a prediction model creation device described in Japanese Patent No. 7085039.

[0078] For example, the prediction model creation device is a device that creates an exhaust gas concentration prediction model that predicts the concentration of a gas component contained in the exhaust gas discharged from the furnace body 30. The prediction model creation device includes an image acquisition unit, an extraction unit, an exhaust gas concentration acquisition unit, and a model creation unit. The image acquisition unit acquires an image of the combustion region of the furnace body 30. The extraction unit converts the image into color image data divided into a plurality of color regions according to RGB values ​​by clustering processing, and extracts the total number of pixels of at least one of the plurality of color regions that has a predetermined correlation or higher with the concentration of the gas component as a feature. The exhaust gas concentration acquisition unit acquires the concentration of the gas component contained in the exhaust gas downstream of the combustion region after a preset set time has elapsed from the time when the image was captured. The model creation unit creates the exhaust gas concentration prediction model by machine learning learning data in which the feature amount extracted by the extraction unit and the concentration of the gas component acquired by the exhaust gas concentration acquisition unit are associated with each other.

[0079] Although the NOx emissions are reduced by injecting EGR gas from the bottom of the furnace and burning it, there is a problem that the burnout point is pushed back. To solve this problem, it is necessary to increase the O2 concentration, which can be achieved by mixing air with the EGR. In addition, the position of the burnout point varies depending on the O2 concentration, so there is an optimum point. Therefore, in order to set the burnout performance to an arbitrary value, the O2 concentration of the gas injected from the bottom of the furnace is controlled to a desired concentration by mixing air with the EGR. This can be achieved by increasing the temperature of the combustion gas in the furnace body 30 by increasing the O2 concentration.

[0080] In addition, mixing EGR into the combustion air and burning it reduces NOx, but as a trade-off, CO increases. In order to control this CO and NOx at the optimum point, it is necessary to control the amount of EGR mixed into the combustion air (OFA). Whether or not CO remains in the secondary combustion zone is closely related to CO in the primary combustion zone. Therefore, the amount of EGR to mix in the secondary combustion zone is determined by monitoring combustion in the primary combustion zone.

[0081] The above-described process performed by the combustion equipment 1 is merely an example, and the process performed by the combustion equipment 1 is not limited to the above-described process. For example, the combustion equipment 1 may perform the process described below.

[0082] (Processing performed by combustion equipment) Here, the detection unit 95 predicts at least one of the O2 concentration, NOx concentration, CO concentration, CO2 concentration, and the air ratio of the primary combustion region in the furnace body 30 by the exhaust gas concentration prediction model created by the prediction model creation device described above. Figure 19 is a diagram showing an example of a process flow in which the combustion equipment 1 according to the second embodiment of the present disclosure controls EGR to be mixed in accordance with at least one of O2, NOx, CO, CO2, and the primary combustion region. Also, Figure 20 is a diagram showing an example of a process flow in which the combustion equipment 1 according to the second embodiment of the present disclosure controls EGR in accordance with at least one of O2, NOx, CO, CO2, and the primary combustion region and the stoker speed.

[0083] First, the process performed by the combustion equipment 1 shown in Fig. 19 will be described. The detection unit 95 detects at least one of a decrease in O2, a decrease in NOx, an increase in CO, an increase in CO2, and a decrease in the air ratio in the primary combustion area in the primary combustion area (step S1). The control unit 130 increases the O2 concentration, increases the NOx concentration, decreases the CO concentration, decreases the CO2 concentration, or increases the air ratio in the primary combustion area in response to the detection by mixing air with the EGR discharged from the first EGR nozzle 91 (step S2). The detection unit 95 detects whether or not there is a sign of an increase in O2, whether or not there is a sign of an increase in NOx, whether or not there is a sign of a decrease in CO, whether or not there is a sign of a decrease in CO2, or whether or not there is a sign of an increase in the air ratio in the primary combustion area in response to the detection (step S3).

[0084] If the detection unit 95 does not detect a sign corresponding to the detection (NO in step S3), the process returns to step S2. If the detection unit 95 detects a sign corresponding to the detection (YES in step S3), the gas sensor 81 detects the O2 concentration, NOx concentration, CO concentration, CO2 concentration, or air ratio in the primary combustion region according to the sign (step S4). The control unit 130 determines whether the O2 concentration, NOx concentration, CO concentration, CO2 concentration, or air ratio in the primary combustion region detected by the gas sensor 81 is equal to or greater than a predetermined concentration or a predetermined air ratio (step S5).

[0085] When the control unit 130 determines that the O2 concentration, NOx concentration, CO concentration, CO2 concentration, or air ratio in the primary combustion region detected by the gas sensor 81 is equal to or greater than a predetermined concentration or a predetermined air ratio (YES in step S5), the control unit 130 ends the process. When the control unit 130 determines that the O2 concentration, NOx concentration, CO concentration, CO2 concentration, or air ratio in the primary combustion region detected by the gas sensor 81 is equal to or less than a predetermined concentration or a predetermined air ratio (NO in step S5), the control unit 130 reduces the flow rate of EGR mixed with the air to be injected into the secondary combustion region, for example, by controlling the flow rate of the first EGR nozzle 91 or the second EGR nozzle 93 (step S6). Then, the detection unit 95 detects whether or not there is a sign of an increase in O2, whether or not there is a sign of an increase in NOx, whether or not there is a sign of a decrease in CO, whether or not there is a sign of a decrease in CO2, or whether or not there is a sign of an increase in the air ratio in the primary combustion region (step S7).

[0086] If the detection unit 95 does not detect a sign (NO in step S7), the process returns to step S6. If the detection unit 95 detects a sign (YES in step S7), the gas sensor 81 detects the O2 concentration, NOx concentration, CO concentration, CO2 concentration, or air ratio in the primary combustion region corresponding to the detected sign (step S8). The control unit 130 determines whether the O2 concentration, NOx concentration, CO concentration, CO2 concentration, or air ratio in the primary combustion region detected by the gas sensor 81 is equal to or greater than a predetermined concentration or a predetermined air ratio (step S9).

[0087] When the control unit 130 determines that the O2 concentration, NOx concentration, CO concentration, CO2 concentration, or air ratio in the primary combustion region detected by the gas sensor 81 is equal to or greater than a predetermined concentration or a predetermined air ratio (YES in step S9), the control unit 130 ends the process. When the control unit 130 determines that the O2 concentration, NOx concentration, CO concentration, CO2 concentration, or air ratio in the primary combustion region detected by the gas sensor 81 is less than a predetermined concentration or a predetermined air ratio (NO in step S9), the control unit 130 controls the second EGR nozzle 93 to reduce the flow rate of EGR discharged from the rear ceiling portion 57 by the second EGR nozzle 93 (step S10). Then, the detection unit 95 detects whether or not there is a sign of an increase in O2, whether or not there is a sign of an increase in NOx, whether or not there is a sign of a decrease in CO, whether or not there is a sign of a decrease in CO, or whether or not there is a sign of an increase in the air ratio in the primary combustion region (step S11).

[0088] If the detection unit 95 does not detect a sign (NO in step S11), the process returns to step S10. If the detection unit 95 detects a sign (YES in step S11), the gas sensor 81 detects the O2 concentration, the NOx concentration, the CO concentration, the CO2 concentration, or the air ratio in the primary combustion region at a predetermined concentration or a predetermined air ratio (step S12). The control unit 130 determines whether the O2 concentration, the NOx concentration, the CO concentration, the CO2 concentration, or the air ratio in the primary combustion region detected by the gas sensor 81 is equal to or greater than the predetermined concentration or a predetermined air ratio (step S13).

[0089] When the control unit 130 determines that the O2 concentration, NOx concentration, CO concentration, CO2 concentration, or air ratio in the primary combustion region detected by the gas sensor 81 is equal to or greater than a predetermined concentration or a predetermined air ratio (YES in step S13), the control unit 130 ends the process. When the control unit 130 determines that the O2 concentration, NOx concentration, CO concentration, CO2 concentration, or air ratio in the primary combustion region detected by the gas sensor 81 is equal to or less than a predetermined concentration or a predetermined air ratio (NO in step S13), the control unit 130 returns to the process of step S10.

[0090] Next, the process performed by the combustion equipment 1 shown in FIG. 20 will be described. The detection unit 95 detects the deterioration of the burnout performance (step S21). The control unit 130 increases the O2 concentration, increases the NOx concentration, decreases the CO concentration, decreases the CO2 concentration, or increases the air ratio in the primary combustion region by mixing air with the EGR discharged from the first EGR nozzle 91 in response to the detection by the detection unit 95 (step S22). The control unit 130 reduces the speed of the stoker 40 (step S23). The control unit 130 increases the flow rate of the EGR discharged from the second EGR nozzle 93 by controlling the second EGR nozzle 93 (step S24). Note that the control of the first EGR nozzle 91 and the second EGR nozzle 93 by the control unit 130 described here with reference to FIG. 20 is an example, and is not limited thereto. For example, as shown below, the direction of increase / decrease (i.e., whether it increases or decreases) of the EGR flow rate discharged from the second EGR nozzle 93 may be the same as or opposite to the direction of increase / decrease in the O2 concentration, the NOx concentration, the CO concentration, the CO2 concentration, or the air ratio in the primary combustion region.

[0091] FIG. 21 is a diagram showing an image of the process performed by the control unit 130 according to the second embodiment of the present disclosure. In order to balance the air ratios, a target air ratio is set, and each gas amount is controlled, for example, by PID (Proportional Integral Differential) control (part (a) of FIG. 21). As a result, the under-grate (primary) air is always controlled without excess or deficiency with respect to the garbage. The processing unit that performs the PID control may be, for example, a change amount determiner. The change amount determiner may perform at least one of P control, I control, and D control. In addition, the first combustion gas and the second combustion gas can be controlled by prioritizing each of them as in the process flow (control logic) shown in FIG. 19 (parts (b) of FIG. 21, (c) of FIG. 21, and (d) of FIG. 21). For example, when the air ratio under the grate is 1.0, the first combustion gas air ratio is 0.1, and the second combustion gas air ratio is 0.1, it is possible to adjust the air amount to the target by prioritizing the range of the air ratio likelihood of each input gas, and the optimal local air ratio state for reducing NOx is maintained. If the quality or amount of garbage on the grate fluctuates, for example, if the air under the grate decreases, a control such as simply increasing either or both of the first and second combustion gases in conjunction with each other may increase the NOx emitted from the EGR section depending on the situation inside the furnace, and may not be able to reduce NOx. It is necessary to increase or decrease the air ratio in accordance with the air ratio of the combustion field at the first and second combustion gas injection positions, taking into account local deviations and time delays. In other words, the control unit 130 may control the second EGR nozzle 93 according to the state of the target air ratio inside the furnace body 30. This type of control by the control unit 130 is different from the control performed in the invention described in Patent Document 2, which behaves independently with respect to each target value and increases the gas amount of the intermediate nozzle when the air under the grate decreases.

[0092] The combustion equipment 1 according to the second embodiment of the present disclosure has been described above. The combustion equipment 1 includes a detection unit 95 that detects a decrease in the O2 concentration in the primary combustion region, which is a region in the furnace body 30, and a control unit 130 that performs control to increase the O2 concentration of the first combustion gas when the detection unit 95 detects a decrease in the O2 concentration in the primary combustion region, and performs control to increase the O2 concentration of the second combustion gas when an increase in the O2 concentration in the primary combustion region or a sign of such an increase is not detected even after the above control is performed. This combustion equipment 1 can optimize the NOx concentration and the CO concentration.

[0093] (Other embodiments) The combustion equipment 1 according to another embodiment of the present disclosure may learn the relationship between the controlled variable and the outlet gas concentration by machine learning, and detect a sign of improvement in exhaust gas performance. In this case, the controlled variable is the flow rate of the mixed air or EGR, or the stoker speed.

[0094] 22 is a hardware configuration diagram showing the configuration of a computer 1100 according to an embodiment. The computer 1100 includes, for example, a processor 1110, a main memory 1120, a storage 1130, and an interface 1140.

[0095] Each of the functional units of the control device 100 described above is implemented in a computer 1100. The operation of each of the functional units described above is stored in the form of a program in a storage 1130. The processor 1110 reads the program from the storage 1130, loads it in the main memory 1120, and executes the above-mentioned processing in accordance with the program. The processor 1110 also secures a storage area in the main memory 1120 for use by each of the functional units described above in accordance with the program.

[0096] The program may be for realizing a part of the functions to be performed by the computer 1100. For example, the program may be for realizing the functions by combining with other programs already stored in the storage 1130 or by combining with other programs implemented in other devices. The computer 1100 may include a custom LSI (Large Scale Integrated Circuit) such as a PLD (Programmable Logic Device) in addition to the above configuration or instead of the above configuration. Examples of PLDs include a PAL (Programmable Array Logic), a GAL (Generic Array Logic), a CPLD (Complex Programmable Logic Device), and an FPGA (Field Programmable Gate Array). In this case, a part or all of the functions to be realized by the processor 1110 may be realized by the integrated circuit.

[0097] Examples of the storage 1130 include a magnetic disk, a magneto-optical disk, and a semiconductor memory. The storage 1130 may be an internal medium directly connected to the bus of the computer 1100, or an external medium connected to the computer 1100 via the interface 1140 or a communication line. When the program is distributed to the computer 1100 via a communication line, the computer 1100 that receives the program may load the program in the main memory 1120 and execute the above-mentioned process. The program may be for realizing part of the above-mentioned functions. Furthermore, the program may be a program that realizes the above-mentioned functions in combination with other programs already stored in the storage 1130, that is, a so-called difference file (difference program).

[0098] <Additional Notes> The combustion equipment and the control method described in each embodiment can be understood, for example, as follows.

[0099] (1) The combustion equipment (1) of the first aspect is a furnace (60) into which the combustion gas flows; A furnace body (30) which includes a drying stage (30a), a combustion stage (30b), and a post-combustion stage (30c) and transports the incineration material (S) while combusting it, the furnace body (30) having a front ceiling part (55) extending forward from the furnace (60), a rear ceiling part (57) extending rearward from the furnace (60), and a rear wall (59) extending downward from the rear end part of the rear ceiling part (57), where the upstream side in the transport direction of the incineration material (S) is referred to as the front and the downstream side in the transport direction is referred to as the rear; a first nozzle (91) provided in a region of the rear ceiling portion (57) rearward of a center of the rear ceiling portion (57) in the transfer direction or in the rear wall (59), and discharging a first combustion gas forward; a second nozzle (93) that is provided in the rear ceiling portion (57) at a position forward of the first nozzle (91) and that discharges a second combustion gas from the rear ceiling portion (57) toward the drying stage (30a) or the combustion stage (30b); a control unit (130) that controls an amount of the second combustion gas discharged from the second nozzle (93) based on a target air ratio in a primary combustion zone that is a zone within the furnace body (30); Equipped with.

[0100] According to this configuration, the flow of the first combustion gas discharged from the first nozzle is changed by the second combustion gas discharged from the second nozzle. This changes the way the air and EGR are mixed, and the combustion of the material to be incinerated can be promoted. As a result, appropriate combustion, such as low NOx, can be achieved.

[0101] (2) A second aspect of the combustion equipment (1) is the combustion equipment (1) described in (1), wherein the second nozzle (93) is provided in a region of the rear ceiling portion (57) forward of the center of the rear ceiling portion (57) in the conveying direction.

[0102] According to this configuration, the second nozzle can be more appropriately installed.

[0103] (3) A third aspect of the combustion equipment (1) is the combustion equipment described in (2), wherein the second nozzle (93) may be provided in the frontmost area of ​​the four areas when the rear ceiling portion (57) is virtually divided into four areas in the transport direction.

[0104] According to this configuration, the second nozzle can be more appropriately installed.

[0105] (4) A fourth aspect of the combustion equipment (1) is the combustion equipment (1) described in any one of (1) to (3), wherein the second nozzle (93) may discharge the second combustion gas in a direction included in an angle range of 60° or more and 90° or less with respect to the horizontal direction, when the horizontal front is defined as 0°.

[0106] According to this configuration, the second nozzle can be more appropriately installed.

[0107] (5) A fifth aspect of the combustion equipment (1) is the combustion equipment (1) according to any one of (1) to (4), further comprising: a plurality of first nozzles (91) that include the first nozzle (91) and are provided in a region of the rear ceiling portion (57) rearward of a center of the rear ceiling portion (57) in the transport direction or in the rear wall (59) and discharge the first combustion gas forward; A plurality of imaginary lines may be defined, each extending forward from the first nozzles (91), and the second nozzle (93) may be disposed between the imaginary lines when viewed from above.

[0108] According to such a configuration, it is possible to reduce interference between the first combustion gas discharged from the first nozzle and the second combustion gas discharged from the second nozzle.

[0109] (6) A sixth aspect of the combustion equipment (1) is the combustion equipment (1) described in any one of (1) to (5), wherein the first nozzle (91) is provided in the rear wall (59) and discharges the first combustion gas in a direction to form a wall jet along the rear ceiling portion (57).

[0110] According to this configuration, it is possible to promote mixing of the first combustion gas discharged from the first nozzle with the air.

[0111] (7) A seventh aspect of the combustion equipment (1) is the combustion equipment (1) according to any one of (1) to (6), A detection unit (95) for detecting a decrease in the oxygen concentration in the primary combustion area; Equipped with The control unit (130) When the detection unit (95) detects a decrease in the oxygen concentration in the primary combustion area, control is performed to increase the oxygen concentration of the first combustion gas, and when the above control does not detect an increase in the oxygen concentration in the primary combustion area or a sign of such an increase, control is performed to increase the oxygen concentration of the second combustion gas.

[0112] According to this configuration, the NOx concentration and the CO concentration can be optimized.

[0113] (8) The eighth aspect of the combustion equipment (1) is the combustion equipment (1) according to any one of (1) to (7), an angle adjustment mechanism (97) capable of changing a discharge direction of the second combustion gas from the second nozzle (93); a sensor (81) for detecting components contained in the gas after the combustion or the gas that has passed through the furnace (60); a control unit (130) that controls the angle adjustment mechanism (97) based on a detection result of the sensor (81); It may further comprise:

[0114] According to this configuration, the direction of the second combustion gas discharged from the second nozzle can be appropriately adjusted.

[0115] (9) A control method according to a ninth aspect of the present invention comprises the steps of: A method for controlling a combustion facility (1), comprising the steps of: The combustion equipment (1) comprises: a furnace (60) into which the combustion gas flows; A furnace body (30) including a drying stage (30a), a combustion stage (30b), and a post-combustion stage (30c), which transports the incineration material (S) while combusting it, the furnace body (30) having a front ceiling portion (55) extending forward from the furnace (60), a rear ceiling portion (57) extending rearward from the furnace (60), and a rear wall (59) extending downward from the rear end of the rear ceiling portion (57), when the upstream side in the transport direction of the incineration material (S) is referred to as the front and the downstream side in the transport direction is referred to as the rear, a first nozzle (91) provided in a region of the rear ceiling portion (57) rearward of a center of the rear ceiling portion (57) in the transfer direction or in the rear wall (59), and discharging a first combustion gas forward; a second nozzle (93) that is provided in the rear ceiling portion (57) at a position forward of the first nozzle (91) and that discharges a second combustion gas from the rear ceiling portion (57) toward the drying stage (30a) or the combustion stage (30b); Equipped with One or more computers (1100) an amount of the second combustion gas discharged from the second nozzle (93) is controlled based on a target air ratio in a primary combustion zone, which is a zone in the furnace body (30); This includes:

[0116] According to this configuration, the flow of the first combustion gas discharged from the first nozzle is changed by the second combustion gas discharged from the second nozzle. This changes the way the air and EGR are mixed, and the combustion of the material to be incinerated can be promoted. As a result, appropriate combustion, such as low NOx, can be achieved. [Explanation of symbols]

[0117] 1. Combustion equipment 2. Storage section 3. Incinerator 11. Garbage pit 12…Crane 21…Hopper 22…Feeder 23...Extrusion device 24...Moisture meter 25…Water sprinkler system 30…Furnace body 31...Oven temperature sensor 32…Visible light camera 33…Infrared camera 40…Stalker 50...Wind box 51...Wind box pressure sensor 55...Front ceiling part 57…Rear ceiling 59...Back wall 60...furnace 60a…Front wall 60b…Back wall 70...Blower mechanism 71...Blower 73...Air preheater 75…Damper 81...Gas sensor 91…No. 1 EGR nozzle 93…Second EGR nozzle 95…Detection unit 97…Angle adjustment mechanism 100...Control device 110…Information acquisition department 120...Flame information derivation section 130...Control unit 140...Powder layer height output section S: Items to be incinerated

Claims

1. a furnace into which the combustion gas flows; A furnace body including a drying stage, a combustion stage, and a post-combustion stage, which transports the incineration material while burning it, and in which the upstream side of the transport direction of the incineration material is referred to as the front and the downstream side of the transport direction is referred to as the rear, the furnace body having a front ceiling portion extending forward from the furnace, a rear ceiling portion extending rearward from the furnace, and a rear wall extending downward from the rear end of the rear ceiling portion; a first nozzle provided in a region of the rear ceiling portion rearward of a center of the rear ceiling portion in the transport direction or in the rear wall, the first nozzle discharging a first combustion gas forward; A second nozzle is provided in the rear ceiling portion at a position forward of the first nozzle, and discharges a second combustion gas from the rear ceiling portion toward the drying stage or the combustion stage; A detection unit that detects a decrease in NOx concentration in a primary combustion region that is a region within the furnace body; a control unit that controls the amount of the second combustion gas discharged from the second nozzle based on a target air ratio in the primary combustion zone, and when a decrease in the NOx concentration in the primary combustion zone is detected by the detection unit, performs control to reduce the flow rate of the first combustion gas, and when an increase in the NOx concentration in the primary combustion zone or a sign of such an increase is not detected even after performing control to reduce the flow rate of the first combustion gas; Combustion equipment equipped with:

2. A furnace into which combustion gas flows; A furnace body including a drying stage, a combustion stage, and a post-combustion stage, which transports the incineration material while burning it, and in which the upstream side of the transport direction of the incineration material is referred to as the front and the downstream side of the transport direction is referred to as the rear, the furnace body having a front ceiling portion extending forward from the furnace, a rear ceiling portion extending rearward from the furnace, and a rear wall extending downward from the rear end of the rear ceiling portion; a first nozzle provided in a region of the rear ceiling portion rearward of a center of the rear ceiling portion in the transport direction or in the rear wall, the first nozzle discharging a first combustion gas forward; A second nozzle is provided in the rear ceiling portion at a position forward of the first nozzle, and discharges a second combustion gas from the rear ceiling portion toward the drying stage or the combustion stage; A detection unit that detects a decrease in oxygen concentration in a primary combustion region, which is a region in the furnace body; a control unit that controls the amount of the second combustion gas discharged from the second nozzle based on a target air ratio in the primary combustion zone, and when a decrease in the oxygen concentration in the primary combustion zone is detected by the detection unit, performs control to increase the oxygen concentration of the first combustion gas, and when an increase in the oxygen concentration in the primary combustion zone or a sign of such an increase is not detected even after the control to increase the oxygen concentration of the first combustion gas is performed, performs control to increase the oxygen concentration of the second combustion gas; Combustion equipment equipped with:

3. The second nozzle is provided in a region of the rear ceiling portion that is forward of a center of the rear ceiling portion in the transport direction. The combustion facility according to claim 2.

4. When the rear ceiling portion is virtually divided into four in the transport direction, the second nozzle is provided in a frontmost area of ​​the four divided areas. The combustion facility according to claim 3.

5. the second nozzle discharges the second combustion gas in a direction included in an angle range of 60° or more and 90° or less with respect to the horizontal direction, when a horizontal forward direction is defined as 0°; The combustion facility according to any one of claims 2 to 4.

6. a plurality of first nozzles including the first nozzle and provided in a region of the rear ceiling portion rearward of a center of the rear ceiling portion in the transport direction or in the rear wall, the first nozzles discharging the first combustion gas forward; defining a plurality of imaginary lines each extending forward from the plurality of first nozzles, and when viewed from above, the second nozzle is disposed between the plurality of imaginary lines; The combustion facility according to any one of claims 1 to 4.

7. The first nozzle is provided on the rear wall and discharges the first combustion gas in a direction to form a wall jet along the rear ceiling portion. The combustion facility according to any one of claims 1 to 4.

8. an angle adjustment mechanism capable of changing a discharge direction of the second combustion gas from the second nozzle; a sensor for detecting components contained in the gas after combustion or the gas that has passed through the furnace; A control unit that controls the angle adjustment mechanism based on a detection result of the sensor; Further comprising: The combustion facility according to any one of claims 1 to 4.

9. A method for controlling a combustion facility, comprising: The combustion facility includes: a furnace into which the combustion gas flows; A furnace body including a drying stage, a combustion stage, and a post-combustion stage, which transports the incineration material while burning it, and in which the upstream side of the transport direction of the incineration material is referred to as the front and the downstream side of the transport direction is referred to as the rear, the furnace body having a front ceiling portion extending forward from the furnace, a rear ceiling portion extending rearward from the furnace, and a rear wall extending downward from the rear end of the rear ceiling portion; a first nozzle provided in a region of the rear ceiling portion rearward of a center of the rear ceiling portion in the transport direction or in the rear wall, the first nozzle discharging a first combustion gas forward; A second nozzle is provided in the rear ceiling portion at a position forward of the first nozzle, and discharges a second combustion gas from the rear ceiling portion toward the drying stage or the combustion stage; A detection unit that detects a decrease in oxygen concentration in a primary combustion region, which is a region in the furnace body; Equipped with One or more computers controlling an amount of the second combustion gas discharged from the second nozzle based on a target air ratio in the primary combustion zone; When a decrease in the NOx concentration in the primary combustion area is detected, a control is performed to decrease the flow rate of the first combustion gas, and when an increase in the NOx concentration in the primary combustion area or a sign of such an increase is not detected even after the control to decrease the flow rate of the first combustion gas, a control is performed to decrease the flow rate of the second combustion gas. The control method includes:

10. A method for controlling a combustion facility, comprising: The combustion facility includes: a furnace into which the combustion gas flows; A furnace body including a drying stage, a combustion stage, and a post-combustion stage, which transports the incineration material while burning it, and in which the upstream side of the transport direction of the incineration material is referred to as the front and the downstream side of the transport direction is referred to as the rear, the furnace body having a front ceiling portion extending forward from the furnace, a rear ceiling portion extending rearward from the furnace, and a rear wall extending downward from the rear end of the rear ceiling portion; a first nozzle provided in a region of the rear ceiling portion rearward of a center of the rear ceiling portion in the transport direction or in the rear wall, the first nozzle discharging a first combustion gas forward; A second nozzle is provided in the rear ceiling portion at a position forward of the first nozzle, and discharges a second combustion gas from the rear ceiling portion toward the drying stage or the combustion stage; A detection unit that detects a decrease in oxygen concentration in a primary combustion region, which is a region in the furnace body; Equipped with One or more computers controlling an amount of the second combustion gas discharged from the second nozzle based on a target air ratio in the primary combustion zone; When the detection unit detects a decrease in the oxygen concentration in the primary combustion area, the control unit increases the oxygen concentration of the first combustion gas, and when the control unit does not detect an increase in the oxygen concentration in the primary combustion area or a sign of such an increase, the control unit increases the oxygen concentration of the second combustion gas. The control method includes:

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