Combustion facility and control method

Abstract

This combustion facility comprises: a furnace into which gas after combustion flows; a furnace body that includes a drying stage, a combustion stage, and a post-combustion stage and conveys an object to be incinerated while burning the object, the furnace body having, when referring to the upstream side in the conveyance direction of the object to be incinerated as the front and the downstream side in the conveyance direction as the rear, a front ceiling part extending frontward from the furnace, a rear ceiling part extending rearward from the furnace, and a rear wall extending downward from a rear end part of the rear ceiling part; a first nozzle that is provided to the rear wall or a region to the rear from the center of the rear ceiling part in the conveyance direction in the rear ceiling part, and discharges a first combusting gas toward the front; a second nozzle that is provided at a position on the front side from the first nozzle in the rear ceiling part and discharges a second combusting gas from the rear ceiling part toward the drying stage or the combustion stage; and a control unit that controls the amount of the second combusting gas to be discharged by the second nozzle on the basis of a target air ratio in a primary combustion region which is a region in the furnace body.

Description

Combustion equipment and control method

[0001] This application claims priority to Japanese Patent Application No. 2024-062780, filed on April 9, 2024, the contents of which are incorporated herein by reference.

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

[0003] Patent No. 5430210 Patent No. 7199305

[0004] However, in the incinerator 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 aims to provide combustion equipment and a control method that can achieve appropriate combustion.

[0006] In order to solve the above problems, the combustion equipment of the present disclosure comprises a furnace into which combusted gas flows, 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, the furnace body having 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 of ​​the rear ceiling section rearward of the center of the rear ceiling section in the transport direction or on 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 the 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.

[0007] The combustion control method according to the present disclosure is a control method for combustion equipment, the combustion equipment comprising a furnace body including a furnace into which combustion gas flows, 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, the furnace body having 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 an area of ​​the rear ceiling section rearward of the center of the rear ceiling section in the transport direction or on the rear wall, and which discharges a first combustion gas forward, and a second nozzle 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 toward the drying stage or the combustion stage, and one or more computers controlling the amount of the second combustion gas discharged by the second nozzle based on a target air ratio in a primary combustion zone, which is an area within the furnace body.

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

[0009] 1 is a diagram showing an example of the configuration of combustion equipment according to the first embodiment of the present disclosure. FIG. 2 is a diagram showing an example of the configuration of a storage unit according to the first embodiment of the present disclosure. FIG. 3 is a diagram showing an example of the configuration of combustion equipment according to the first embodiment of the present disclosure. FIG. 4 is a diagram showing an example of a gas flow in combustion equipment that does not include a second EGR nozzle. FIG. 5 is a diagram showing an example of a gas flow in combustion equipment that includes a second EGR nozzle according to the first embodiment of the present disclosure. FIG. 6 is a diagram showing an example of a relationship between an angle at which the second EGR nozzle according to the first embodiment of the present disclosure discharges gas and combustion. FIG. 7 is a diagram showing an example of a relationship between a position at which the second EGR nozzle according to the first embodiment of the present disclosure discharges gas and combustion. FIG. 8 is a diagram showing an example of a gas flow velocity in combustion equipment that does not include a second EGR nozzle. FIG. 9 is a diagram showing an example of a gas flow velocity in combustion equipment 1 that includes a second EGR nozzle according to the first embodiment of the present disclosure. FIG. 10 is a diagram showing an example of SRg in combustion equipment 1 that does not include a second EGR nozzle. FIG. 11 is a diagram showing an example of SRg in combustion equipment 1 that includes a second EGR nozzle according to the first embodiment of the present disclosure. FIG. 12 is a diagram showing an example of a NOx concentration distribution in combustion equipment that does not include a second EGR nozzle. FIG. 1 is a diagram showing an example of a NOx concentration distribution in combustion equipment 1 including a second EGR nozzle according to the first embodiment of the present disclosure. FIG. 2 is a diagram showing an example of installation positions of a first EGR nozzle and a second EGR nozzle according to the first embodiment of the present disclosure. FIG. 3 is a diagram showing an example of a gas flow around the EGR nozzle according to the first embodiment of the present disclosure. FIG. 4 is a diagram showing a first example of a gas flow discharged from the first EGR nozzle due to gas discharged from the second EGR nozzle according to the first embodiment of the present disclosure. FIG. 5 is a diagram showing an example of a relationship between the flow of gas discharged from the second EGR nozzle and the flow of gas discharged from the first EGR nozzle according to the first embodiment of the present disclosure. FIG. 6 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 to be mixed according to O2. FIG. 7 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 according to O2 and stoker speed. FIG. 8 is a diagram showing an image of processing performed by a control unit 130 according to the second embodiment of the present disclosure. FIG. 9 is a hardware configuration diagram showing the configuration of a computer according to an embodiment.

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following description, components having the same or similar functions will be assigned the same reference numerals. Duplicate descriptions of those components may be omitted. In this disclosure, "based on XX" means "based on at least XX" and may include cases where the component is based on another element in addition to XX. Furthermore, "based on XX" is not limited to cases where XX is directly used, but may also include cases where XX has been calculated or processed. In this disclosure, "XX or YY" is not limited to cases where either XX or YY is used, but may include cases where both XX and YY are used. This also applies when there are three or more optional elements. "XX" and "YY" are arbitrary elements (e.g., arbitrary information).

[0011] In this application, "acquire" is not limited to actively acquiring by sending a transmission request, but may also include passively receiving information transmitted from another device. Furthermore, "acquire" is not limited to directly acquiring target information (information to be acquired) from outside, but may also include generating and acquiring target information by performing calculations or processing on information acquired 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." Note that, for convenience of explanation, the upstream side in the transport direction of the incineration material may be referred to as the "front" and the downstream side in the transport direction as the "rear." Furthermore, the "front side" may be referred to as the "front furnace side" and the "rear side" as the "end of furnace side." 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 Facility) FIG. 1 is a diagram showing an example of the configuration of combustion facility 1 according to a first embodiment of the present disclosure. For example, the combustion facility 1 is a stoker furnace for incinerating materials S, such as municipal solid waste, industrial waste, or biomass. Note that the combustion facility 1 is not limited to a stoker furnace and may be another type of combustion facility. For ease 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 material S. The incinerator 3 is a furnace that combusts the incineration material S fed from the storage section 2 while transporting it. Exhaust gas is generated in the incinerator 3 as the incineration material S is burned inside the incinerator 3. The generated exhaust gas is sent to a heat recovery boiler 4 located at the top of the incinerator 3. The heat recovery boiler 4 heats the water and generates steam by exchanging heat between the exhaust gas generated in the incinerator 3 and water. The exhaust gas that passes through the heat recovery boiler 4 is cooled in a cooling 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 Unit) 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 garbage 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 control instructions 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 control instructions 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 area R where the material to be incinerated S can be grasped, and dumps the grasped material to be incinerated S into the hopper 21.

[0019] 1, the incinerator 3 will now be described in detail. The incinerator 3 includes, 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 temporarily stores the materials to be incinerated S transported by the crane 12 and sequentially supplies them to the 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 sprinkler device 25.

[0021] (Hopper) The hopper 21 is a storage section provided to supply the materials to be incinerated S into the furnace body 30. The hopper 21 has an inlet section for introducing the materials to be incinerated S and an outlet section that leads to the 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 introduced 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 the shape of a plate that fits along the bottom of the hopper 21. The feeder 22 is driven by a push-out device 23 and is capable of reciprocating movement in a direction from the hopper 21 toward the treatment space V of the furnace body 30. The feeder 22 is driven by the push-out device 23 and pushes the materials 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 materials S placed in the hopper 21. For example, the moisture meter 24 includes an irradiation unit, a detection unit, and an analysis unit, all of which are provided in the hopper 21. The irradiation unit irradiates electromagnetic waves in a predetermined frequency band onto the incineration materials S piled up in the hopper 21. The detection unit receives the electromagnetic waves irradiated from the irradiation unit and transmitted through or reflected by the incineration materials S. The analysis unit pre-stores correlation information indicating the relationship between the moisture percentage and changes in the characteristics of the electromagnetic waves (e.g., changes in amplitude or phase). The analysis unit detects the moisture percentage of the incineration materials S based on the correlation information and the changes in the characteristics of the electromagnetic waves between the irradiation unit and the detection unit. The moisture meter 24 may also detect the moisture content of the incineration materials S based on the moisture percentage and the weight of the incineration materials S placed in the hopper 21.

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

[0025] (Furnace body) The furnace body 30 is provided adjacent to the hopper 21 and is equipment for burning the materials to be incinerated S while transporting them. Hereinafter, the transport direction of the materials to be incinerated S in the combustion equipment 1 will be 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, from upstream to downstream in the conveying direction D, a drying stage 30a, a combustion stage 30b, and a post-combustion stage 30c, in this order. The furnace body 30 conveys the incineration material S from upstream to downstream while combusting it. The drying stage 30a is located upstream of the combustion stage 30b and the post-combustion stage 30c, and is a region where 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 where the incineration material S, dried after passing through the drying stage 30a, is combusted on the stoker 40. In the combustion stage 30b, diffusion combustion occurs due to pyrolysis gases generated from the incineration material S, generating a flame F. 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] (In-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." Note that 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 interior 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 foot") of the furnace body 30 in the conveying direction D, and photograph the area from the furnace foot 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 materials to be incinerated S (a layer of garbage) piled up on the drying stage 30a of the furnace main body 30 by transmitting light through the flame F. The infrared camera 33 may also capture an image of the outlet of the hopper 21 instead of or in addition to the materials to be incinerated S piled up on the drying stage 30a. That is, the infrared camera 33 may capture an image including the materials to be incinerated S piled up on the feeder 22 at the outlet of the hopper 21 (an image showing the piled state of the materials to be incinerated S). The images captured by the visible light camera 32 and the infrared camera 33 are transmitted to the control device 100. The images captured by the visible light camera 32 or the infrared camera 33 are an example of an "image captured inside the incinerator."

[0030] The infrared camera 33 may be configured, for example, by a plurality of infrared cameras arranged in a stereo system. 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 furnace bottom of the furnace body 30. Either or both of the visible light camera 32 and the infrared camera 33 may be omitted.

[0031] (Stoker) The stoker 40 includes multiple grates 41 and a grate drive device 42 (see FIG. 3). The multiple grates 41 form a stoker surface 40a, which is the bottom surface of the furnace body 30. The material to be incinerated 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, combustion stage 30b, and post-combustion stage 30c described above. The multiple grates 41 include a fixed grate and a movable grate. The fixed grate is fixed to the upper surface of the wind box 50, which will be described later. The movable grate moves back and forth at a constant speed along the transport direction D, stirring and mixing the material to be incinerated S located on the movable grate and the fixed grate (on the stoker surface 40a) while transporting 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 into an ash push-out device located below the furnace body 30. The discharge chute 43 is provided at the end of the furnace body 30. The wall behind the discharge chute 43 is the rear wall 59, which will be described later.

[0033] (Wind Boxes) A ​​plurality of wind boxes 50 are provided below the stoker 40 and supply primary air for combustion into the furnace body 30 through the stoker 40. The primary air is an example of "combustion air". In this embodiment, the plurality of wind boxes 50 are arranged in a line in the conveying direction D, for example, corresponding to the plurality of 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 plurality of 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 top of the furnace body 30. The furnace 60 is positioned above the grate 41, and post-combustion gas flows into it. That is, exhaust gas generated by the combustion of the materials to be incinerated S in the furnace body 30 flows through the furnace 60 to the heat recovery steam generator 4. The furnace 60 includes a front wall 60a located at the front of the space through which the exhaust gas flows, and a rear wall 60b located at the rear of the space through which the exhaust gas flows. The front wall 60a and the rear wall 60b each extend vertically, for example. If the upstream side in the transport direction of the materials to be incinerated S is referred to as the front, and the downstream side in that transport direction 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 into 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 into the furnace body 30 (e.g., the treatment space V) through the primary air line 72 and the multiple air boxes 50. The second blower 71B pressurizes and sends secondary air for combustion into 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 (e.g., multiple) primary air dampers 75A are provided along 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 dampers 75A change the flow rate of primary air flowing from the primary air line 72 into the corresponding wind box 50 depending on the opening degree of the primary air damper 75A. In other words, the distribution amount of primary air among the multiple wind boxes 50 (i.e., which wind box 50 is given priority for supplying primary air 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 a 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 compressed and sent 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 preheating temperature sensor 73a that detects the temperature of the preheated primary air. The detection result of the preheating temperature sensor 73a is another example of "information related to 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 to the space within the furnace 60 (exhaust gas flow path). 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 to the space within the furnace 60 (exhaust gas flow path).

[0040] One or more (e.g., multiple) secondary air dampers 75B are provided along the secondary air line 74. In this embodiment, the multiple secondary air dampers 75B are provided in one-to-one correspondence with the multiple supply ports (e.g., supply ports 74a, 74b) provided in the furnace 60. The secondary air dampers 75B change the amount of secondary air distributed among the multiple supply ports (e.g., supply ports 74a, 74b) (i.e., which supply port is given priority for supplying secondary air into the furnace 60) depending on the opening degree of the secondary air dampers 75B. The opening degree of each secondary air damper 75B and / or a set of opening degrees of multiple secondary air dampers 75B is another example of "information regarding the supply of combustion air." For ease of explanation, the primary air damper 75A and the secondary air damper 75B will hereinafter be collectively referred to as "damper 75."

[0041] The air flow sensor 76 detects the flow rate of combustion air supplied to 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 primary air line 72 and detects the flow rate of primary air supplied through the primary air line 72. The second air flow sensor 76B is provided in the secondary air line 74 and detects the flow rate of 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 related to 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 components), carbon dioxide concentration (hereinafter referred to as "CO2 concentration"), or NOx concentration contained in the exhaust gas, the air ratio in the primary combustion zone, etc. 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 post-combustion gas can be detected). The detection result of the gas sensor 81 is an example of "information about 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 on the rear wall 59 extending downward from the rear end of the rear ceiling portion 57. The first EGR nozzle 91 discharges EGR (an example of a first combustion gas), air, or EGR mixed with air (an example of a first combustion gas) 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 a first combustion gas), air, or EGR (an example of a 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 defined as "X," the vertical distance between the front end and the center of the opening of the first EGR nozzle 91 is defined as "H," the angle formed by the rear ceiling portion 57 and the horizontal plane is defined as "α," and the angle formed by the center line O of the first EGR nozzle 91 and the horizontal plane is defined as "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]

[0046] The horizontal distance here refers to a two-dimensional geometric distance in the horizontal direction. The vertical distance refers to a one-dimensional geometric distance in the vertical direction. The value of "a tan((H / X)+tan(α))-β" on the left side of equation (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 in 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 (an example of a second combustion gas) mixed with air 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 (an example of a second combustion gas) mixed with air 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 section 57 that is forward of the center of the rear ceiling section 57 in the transport direction of the incineration materials S. More specifically, for example, if the rear ceiling section 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 desirable to provide the second EGR nozzle 93 in such a position will be described later.

[0049] In addition, for example, when the forward direction in the horizontal direction is defined as 0°, 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) in a direction included in an angle range of 60° to 90° with respect to the horizontal direction. The reason why it is desirable 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. Figure 4 is a diagram showing an example of a gas flow in combustion equipment not having the second EGR nozzle 93. Figure 5 is a diagram showing an example of a gas flow in 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), air, or EGR mixed with air (an example of a first combustion gas) discharged from the first EGR nozzle 91. The dashed line B in Fig. 4 shows an example of the flow of volatile gases resulting from combustion with 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 gases. In a combustion equipment that does not include the second EGR nozzle 93 as shown in Fig. 4, both the gas discharged from the first EGR nozzle 91 and the volatile gases resulting from combustion with primary air flow toward the furnace 60 along the space within the furnace body 30.

[0052] The dashed line A' 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' in FIG. 5 shows an example of the flow of volatile matter from combustion of primary air injected from below the combustion stage 30b. The dashed line C 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 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 C discharged from the second EGR nozzle 93 pushes the gas flow A shown in FIG. 4 downward, changing the gas flow A' shown in FIG. 5. Gas flow A' shown in Figure 5 pushes gas flow B shown in Figure 4 downward, changing it to gas flow B' shown in Figure 5. In other words, when 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) in a direction within an angle range of 60° to 90° relative to the horizontal direction, assuming that the horizontal direction is 0°, the volatile gases resulting from combustion by the primary air are pushed downward, increasing their residence time within the furnace body 30. As a result, mixing of the volatile gases resulting from combustion by the primary air with the gas discharged from the first EGR nozzle 91 and the second EGR nozzle 93 is further promoted. In other words, combustion of the incineration material S is promoted. Furthermore, the gases of flow A' and flow B' and gas C prevent dry air D from flowing toward 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 injected from below the drying stage 30a, the combustion stage 30b, and the post-combustion stage 30c. In other words, the combustion of the material to be incinerated S in the combustion stage 30b can be controlled.

[0053] FIG. 6 is a diagram illustrating 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 represents the angle at which the second EGR nozzle 93 discharges gas, with the horizontal forward angle being 0°. The left vertical axis in FIG. 6 represents the NOx concentration. The right vertical axis in FIG. 6 represents 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 being 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 equal to or greater than 60° and equal to or less than 90°. Note that the NOx concentration and the CO concentration have a trade-off relationship. Therefore, in practice, an appropriate concentration is determined by balancing the NOx concentration and the CO concentration.

[0054] FIG. 7 is a diagram illustrating 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 forefront of the drying stage 30a being designated 0 and the position at the rearmost end of the drying stage 30a being designated 1. The left vertical axis in FIG. 7 indicates the NOx concentration. The right vertical axis in FIG. 7 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 designated 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 ranges from 0 to approximately 0.25 (i.e., when the rear ceiling section 57 is virtually divided into four regions in the transport direction of the incineration material S and the second EGR nozzle 93 discharges gas in the forwardmost of the four regions). Furthermore, from FIG. 7, it can be seen that the NOx concentration begins to rise significantly when the position at which the second EGR nozzle 93 discharges gas reaches approximately 0.25 (i.e., when the position at which the second EGR nozzle 93 discharges gas exceeds approximately 0.25 in the rear ceiling portion 57). 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 one-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 portion 57 pushes volatile matter toward the end of the furnace and air on the front side of the furnace toward the secondary combustion zone, thereby promoting the formation of the expected air ratio distribution in the end-of-furnace space (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 control the gas flow rates individually.

[0055] FIG. 8 is a diagram showing an example of the gas flow velocity in a combustion equipment that does not include a second EGR nozzle 93. FIG. 9 is a diagram showing an example of the gas flow velocity in a combustion equipment 1 that includes a second EGR nozzle 93 according to the first embodiment of the present disclosure. In FIGS. 8 and 9 , the thickness of the arrows indicates the flow velocity. Also, in FIGS. 8 and 9 , the direction of the arrows indicates the direction of the gas flow. Also, the portion A shown in FIG. 9 indicates a region located between the drying stage 30a and the end of the furnace, where the flow velocity is approximately zero. This region A indicates that in the combustion equipment 1 that includes the second EGR nozzle 93, dry air does not flow toward the end of the furnace. On the other hand, in the combustion equipment that does not include the second EGR nozzle 93 shown in FIG. 8 , the region A shown in FIG. 9 does not exist. In other words, in the combustion equipment that does not include the second EGR nozzle 93, dry air flows toward the end of the furnace.

[0056] FIG. 10 is a diagram showing an example of SRg in combustion equipment that does not include a second EGR nozzle 93. FIG. 9 is a diagram showing an example of SRg in combustion equipment 1 that includes a second EGR nozzle 93 according to the first embodiment of the present disclosure. In FIGS. 8 and 9 , part A indicates a region where SRg is approximately 1. Also, in FIGS. 8 and 9 , part B indicates a region where SRg is greater than region A. Also, in FIGS. 8 and 9 , part C indicates a region where SRg is lower than region A. Note that SRg represents a local air ratio, and the closer SRg is to 1, the better the EGR and air are mixed. Compared to FIG. 8 , in FIG. 9 , region A is wider in the combustion stage 30b and the post-combustion stage 30c, meaning that the EGR and air are well mixed.

[0057] Fig. 12 is a diagram showing an example of NOx concentration distribution in combustion equipment that does not include a second EGR nozzle 93. Fig. 13 is a diagram showing an example of NOx concentration distribution in combustion equipment 1 that includes a second EGR nozzle 93 according to the first embodiment of the present disclosure. 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 wider due to the region where the air ratio is approximately 1 as shown in Fig. 9.

[0058] FIG. 14 is a diagram illustrating 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 viewed from above. The combustion equipment 1 may include multiple first EGR nozzles 91. In this case, the multiple 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 section 57 rearward of the center of the rear ceiling section 57 in the transport direction of the incineration material S or in the rear wall 59 extending downward from the rear end of the rear ceiling section 57. The multiple first EGR nozzles 91 discharge EGR (an example of a first combustion gas), air, or EGR mixed with air (an example of a first combustion gas) forward. Furthermore, multiple imaginary lines are defined extending forward from the multiple first EGR nozzles 91, and when viewed from above, the second EGR nozzle 93 is positioned between the multiple 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 first EGR nozzle 91 may be disposed so as to satisfy the above-described formula (I), thereby promoting the mixing of the gas.

[0059] 14 , when a plurality of first EGR nozzles 91 and a plurality of second EGR nozzles 93 are provided, it is desirable to define a plurality of imaginary lines extending forward from the plurality of first EGR nozzles 91, and to position 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] 15 is a diagram showing an example of the gas flow around the EGR nozzles 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 is sucked into the nozzle. In the embodiment of the present disclosure, this characteristic is utilized by providing the second EGR nozzle 93 at the front end of the rear ceiling portion 57 to prevent unburned gas from flowing into the secondary combustion zone (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 due to 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 due to 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, the post-combustion stage 30c, etc. may fly up, resulting in unnecessary ash being mixed into the gas. Furthermore, if the amount of gas discharged from the second EGR nozzle 93 is too small, the volatile gas from the combustion by the primary air described above is pushed downward, shortening the time it remains in the furnace body 30, thereby reducing the effect of the gas discharged from the second EGR nozzle 93. In other words, it is desirable that the second EGR nozzle 93 discharges gas so as to push the volatile gases from the combustion of the primary air as far downward as possible, without causing ash to fly up.

[0062] 18 is a diagram illustrating 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, flow velocity U0 is the flow velocity of gas discharged from the second EGR nozzle 93, and 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 as to push the volatile gas from the combustion of primary air as far downward as possible without causing ash to fly up, it is necessary to take into account 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 controls the combustion of the materials to be incinerated S in the furnace body 30. In this disclosure, "combustion control" broadly means control related to the combustion of the materials to be incinerated S, and means controlling, for example, one or more of the supply amount of the materials to be incinerated S, the moisture content of the materials to be incinerated S, the transport speed of the materials to be incinerated S, the flow rate and / or distribution amount of primary air, the temperature of the primary air, and the flow rate and / or distribution amount of secondary air.

[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 device 25, the grate drive device 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 Unit) The information acquisition unit 110 acquires 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 incineration target material S), the detection results of the in-furnace temperature sensor 31 (information on the temperature inside the incinerator 3), the image capture results of the visible light camera 32 (information on the combustion flame as seen from the end of the furnace), the image capture 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 status 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 drive status of the feeder 22 by the extrusion device 23 (information regarding the supply amount of the incineration material S, for example, the movement speed and / or stroke length of the feeder 22), control information indicating the drive status of the grate drive device 42 (information regarding the transport speed of the incineration material S), control information indicating the drive rate of the blower 71 (information regarding the supply of combustion air), control information indicating the heating rate 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) The control unit 130 controls the flow velocity of gas discharged from the first EGR nozzle 91 and the second EGR nozzle 93 to a desired flow velocity. Controlling the gas flow velocity also controls the gas flow rate. The control unit 130 also controls the gas discharge direction 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, to suppress the CO concentration, the control unit 130 adjusts the orientation of the angle adjustment mechanism 97 to change the gas discharge direction within a range of 60° to 90°, thereby bringing it closer to 60°. For example, to suppress the NOx concentration, the control unit 130 adjusts the orientation of the angle adjustment mechanism 97 to change the gas discharge direction within a range of 60° to 90°, thereby bringing it closer to 90°. Note that the control by the control unit 130 is control such that the combustion equipment 1 having the second EGR nozzle 93 is dominant over the combustion equipment not having the second EGR nozzle 93. 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 controls so as to obtain the effects described with reference to Figures 9, 11, 13, 16, 17, and 18. Note that the flow velocity of the gas discharged from the first EGR nozzle 91 and the second EGR nozzle 93 may be changed by changing the nozzle diameter.

[0068] Furthermore, the control unit 130 performs combustion control for the incinerator 3 based on values ​​relating 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 materials S to be incinerated, the moisture content of the materials S to be incinerated, the transport speed of the materials S to be incinerated, the supply amount and / or distribution amount of primary air, the temperature of the combustion air (e.g., the temperature of the primary air), the supply amount and / or distribution amount of 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 of the flame F in the depth direction.

[0069] The control unit 130 also controls the extrusion device 23 to change the movement 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 sprinkling water using the sprinkler device 25. The control unit 130 changes the transport 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 controls the blower 71 to change the flow rate of the primary air and / or the flow rate of the secondary air. The control unit 130 changes the temperature of the primary air by 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.

[0070] Furthermore, the control unit 130 performs combustion control for the incinerator 3 based on the position G of the center of gravity of the flame F derived by the flame information derivation unit 120. For example, when the position G of the center of gravity 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 materials S to be incinerated, the moisture content of the materials S to be incinerated, the transport speed of the materials 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 G of the center of gravity of the flame F closer to the planned position.

[0071] For example, if the center of gravity G of the flame F is closer to the end 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 of the incineration material S (e.g., by slowing down the feeder 22's movement speed or shortening the stroke length), maintaining a low moisture content in the incineration material S (e.g., by suppressing water sprinkler 25), slowing the transport speed of the incineration material S (e.g., by slowing down the grate 41's drive speed), increasing the supply of primary air (e.g., by increasing the drive rate of the first blower 71A), increasing the distribution of primary air to the front of the furnace (e.g., by increasing the opening of the primary air damper 75A corresponding to one or more wind boxes 50 located on the front of the furnace), or increasing the preheating temperature of the air preheater 73. On the other hand, if the center of gravity G of the flame F is closer to the front of the furnace than the planned position, the control unit 130 performs the opposite control to the above.

[0072] 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 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 as the rear, the furnace body 30 has a front ceiling section 55 extending forward from the furnace 60, a rear ceiling section 57 extending rearward from the furnace 60, and a rear wall 59 extending downward from the rear end of the rear ceiling section 57, and a region of the rear ceiling section 57 behind the center of the rear ceiling section 57 in the transport direction or 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 in 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.

[0073] This combustion equipment 1 can stabilize exhaust gas components (for example, reduce NOx), that is, this combustion equipment 1 can achieve appropriate combustion.

[0074] The above-described processing performed by the combustion equipment 1 is an example, and the processing performed by the combustion equipment 1 is not limited to the above-described processing. For example, the combustion equipment 1 may perform the processing described below.

[0075] 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 the 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 the 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, if 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, then 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.

[0076] The detection unit 95 may be configured to detect any state (e.g., burnout of a solid layer, combustion flame) inside the furnace body 30. For example, the detection unit 95 may be configured to detect a decrease in the 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.

[0077] 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 exhaust gas discharged from a 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 a combustion region of the furnace body 30. The extraction unit converts the image into color image data that is divided into multiple color regions according to RGB values ​​using a clustering process, and extracts, as a feature, the total number of pixels in at least one color region from the multiple color regions that has a predetermined or higher correlation with the concentration of the gas component. 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 predetermined set time has elapsed since the image was captured. The model creation unit creates the exhaust gas concentration prediction model by machine learning learning data in which the feature extracted by the extraction unit is associated with the concentration of the gas component acquired by the exhaust gas concentration acquisition unit.

[0078] Although NOx emissions are reduced by injecting EGR gas from the end of the furnace and burning it, there is a problem of the burnout point being pushed back. To solve this problem, it is necessary to increase the O2 concentration, which can be achieved by mixing air into the EGR. Furthermore, since the position of the burnout point varies depending on the O2 concentration, 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 end of the furnace is controlled to the desired concentration by mixing air into the EGR. Note that this can be achieved by increasing the O2 concentration and increasing the temperature of the combustion gas in the furnace body 30.

[0079] Furthermore, mixing EGR into combustion air and burning it reduces NOx, but as a trade-off, CO increases. In order to control CO and NOx at an optimal point, it is necessary to control the amount of EGR mixed into the combustion air (OFA). Whether CO remains in the secondary combustion zone is closely related to CO in the primary combustion zone. Therefore, the amount of EGR to be mixed in the secondary combustion zone is determined by monitoring combustion in the primary combustion zone.

[0080] The above-described processing performed by the combustion equipment 1 is an example, and the processing performed by the combustion equipment 1 is not limited to the above-described processing. For example, the combustion equipment 1 may perform the processing described below.

[0081] (Processing Performed by the Combustion Equipment) Here, the detection unit 95 predicts at least one of the O2 concentration, NOx concentration, CO concentration, CO2 concentration, and air ratio of the primary combustion zone in the furnace body 30 using the exhaust gas concentration prediction model created by the prediction model creation device described above. Fig. 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 mixing in accordance with at least one of O2, NOx, CO, CO2, and the primary combustion zone. Fig. 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 zone and the stoker speed.

[0082] 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 zone (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 zone 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 the detection indicates an increase in O2, an increase in NOx, a decrease in CO, a decrease in CO2, or an increase in the air ratio in the primary combustion zone (step S3).

[0083] If the detection unit 95 does not detect any signs corresponding to the detection (NO in step S3), the process returns to step S2. On the other hand, if the detection unit 95 detects any signs 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 zone in accordance with the signs (step S4). The control unit 130 determines whether the O2 concentration, NOx concentration, CO concentration, CO2 concentration, or air ratio in the primary combustion zone detected by the gas sensor 81 is equal to or greater than a predetermined concentration or a predetermined air ratio (step S5).

[0084] When the control unit 130 determines that the O2 concentration, NOx concentration, CO concentration, CO2 concentration, or air ratio in the primary combustion zone 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 terminates 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 zone detected by the gas sensor 81 is 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 injected into the secondary combustion zone, 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 there is a sign of an increase in O2, an increase in NOx, a decrease in CO, a decrease in CO, or an increase in the air ratio in the primary combustion zone (step S7).

[0085] If the detection unit 95 does not detect any signs (NO in step S7), the process returns to step S6. On the other hand, if the detection unit 95 detects any signs (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 zone corresponding to the detected signs (step S8). The control unit 130 determines whether the O2 concentration, NOx concentration, CO concentration, CO2 concentration, or air ratio in the primary combustion zone detected by the gas sensor 81 is equal to or greater than a predetermined concentration or a predetermined air ratio (step S9).

[0086] When the control unit 130 determines that the O2 concentration, NOx concentration, CO concentration, CO2 concentration, or air ratio in the primary combustion zone 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 terminates 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 zone 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 (step S10). Then, the detection unit 95 detects whether there is a sign of an increase in O2, an increase in NOx, a decrease in CO, a decrease in CO, or an increase in the air ratio in the primary combustion zone (step S11).

[0087] If the detection unit 95 does not detect any signs (NO in step S11), the process returns to step S10. If the detection unit 95 detects any signs (YES in step S11), the gas sensor 81 detects the O2 concentration, NOx concentration, CO concentration, CO2 concentration, or the air ratio in the primary combustion zone at a predetermined concentration or predetermined air ratio (step S12). The control unit 130 determines whether the O2 concentration, NOx concentration, CO concentration, CO2 concentration, or the air ratio in the primary combustion zone detected by the gas sensor 81 is equal to or greater than the predetermined concentration or predetermined air ratio (step S13).

[0088] When the control unit 130 determines that the O2 concentration, NOx concentration, CO concentration, CO2 concentration, or air ratio in the primary combustion zone 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 zone detected by the gas sensor 81 is 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.

[0089] Next, the process performed by the combustion equipment 1 shown in FIG. 20 will be described. The detection unit 95 detects a deterioration in burnout performance (step S21). In response to the detection by the detection unit 95, 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 zone by mixing air with the EGR discharged from the first EGR nozzle 91 (step S22). The control unit 130 reduces the speed of the stoker 40 (step S23). The control unit 130 controls the second EGR nozzle 93 to increase the flow rate of the EGR discharged from 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 merely an example and is not limited thereto. For example, as shown below, the direction of increase or decrease (i.e., whether it increases or decreases) of the flow rate of EGR discharged from the second EGR nozzle 93 may coincide with or be opposite to the direction of increase or decrease of the O2 concentration, the NOx concentration, the CO concentration, the CO2 concentration, or the air ratio in the primary combustion region.

[0090] FIG. 21 is a diagram illustrating an example of processing performed by the control unit 130 according to the second embodiment of the present disclosure. To balance the air ratios, a target air ratio is set, and the amount of each gas is controlled, for example, by PID (Proportional Integral Differential) control (part (a) of FIG. 21 ). This ensures that the under-grate (primary) air is always controlled to the right amount relative to the waste. The processing unit that performs 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. Furthermore, the first combustion gas and the second combustion gas can be controlled by prioritizing them, as in the processing flow (control logic) shown in FIG. 19 (parts (b), (c), and (d) of FIG. 21 ). For example, when the under-grate air ratio is 1.0, the first combustion gas air ratio is 0.1, and the second combustion gas air ratio is 0.1, the air ratios can be prioritized within the range of the air ratio likelihood for each input gas, allowing for individual adjustments to the target air volume, thereby maintaining an optimal local air ratio state for reducing NOx. If the quality or amount of refuse on the grate fluctuates, for example, if the under-grate air volume decreases, simply increasing either or both of the first and second combustion gas volumes in tandem may increase NOx emissions from the EGR section depending on the furnace conditions, resulting in failure to achieve low NOx. It is necessary to increase or decrease the air volume in accordance with the combustion field air ratio at the first and second combustion gas injection positions, taking into account local deviations and time delays. In other words, the control unit 130 simply controls the second EGR nozzle 93 according to the target air ratio state within the furnace body 30. This type of control by the control unit 130 differs from the control performed in Patent Document 2, which operates independently for each target value and increases the gas volume from the intermediate nozzle section when the under-grate air volume decreases.

[0091] The combustion equipment 1 according to the second embodiment of the present disclosure has been described above. The combustion equipment 1 includes a detector 95 that detects a decrease in the O2 concentration in a primary combustion zone, which is a region within the furnace body 30, and a controller 130 that, when the detector 95 detects a decrease in the O2 concentration in the primary combustion zone, increases the O2 concentration of the first combustion gas. If the controller 95 does not detect an increase in the O2 concentration in the primary combustion zone or a sign of such an increase, the controller 130 increases the O2 concentration of the second combustion gas. This combustion equipment 1 can optimize NOx and CO concentrations.

[0092] The combustion equipment 1 according to another embodiment of the present disclosure may use machine learning to learn the relationship between the control variable and the outlet gas concentration, and detect signs of improvement in exhaust gas performance. Note that in this case, the control variable is the flow rate of mixed air or EGR, or the stoker speed.

[0093] 22 is a hardware configuration diagram showing the configuration of a computer 1100 according to this embodiment. The computer 1100 includes, for example, a processor 1110, a main memory 1120, a storage 1130, and an interface 1140.

[0094] 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 into the main memory 1120, and executes the above-described processing in accordance with the program. The processor 1110 also allocates storage areas in the main memory 1120 to be used by each of the functional units described above in accordance with the program.

[0095] The program may be for realizing part of the functions to be performed by the computer 1100. For example, the program may be a program that performs the functions in combination with another program already stored in the storage 1130 or in combination with another program installed in another device. Furthermore, the computer 1100 may include a custom LSI (Large Scale Integrated Circuit) such as a PLD (Programmable Logic Device) in addition to or instead of the above configuration. Examples of PLDs include programmable array logic (PAL), generic array logic (GAL), complex programmable logic device (CPLD), and field programmable gate array (FPGA). In this case, some or all of the functions implemented by processor 1110 may be implemented by the integrated circuit.

[0096] Examples of storage 1130 include a magnetic disk, a magneto-optical disk, and a semiconductor memory. Storage 1130 may be an internal medium directly connected to the bus of computer 1100, or an external medium connected to computer 1100 via interface 1140 or a communication line. Furthermore, when this program is distributed to computer 1100 via a communication line, computer 1100 that receives the program may deploy the program in main memory 1120 and execute the above-described processing. Furthermore, the program may be a program for realizing part of the above-described functions. Furthermore, the program may be a so-called differential file (differential program) that realizes the above-described functions in combination with another program already stored in storage 1130.

[0097] <Additional Notes> The combustion equipment and control method described in each embodiment can be understood, for example, as follows.

[0098] (1) A first aspect of the combustion equipment (1) comprises: a furnace (60) into which combustion gas flows; a furnace body (30) including a drying stage (30a), a combustion stage (30b), and a post-combustion stage (30c) for transporting incineration material (S) while combusting the material; and a furnace body (30) having a front ceiling section (55) extending forward from the furnace (60), a rear ceiling section (57) extending rearward from the furnace (60), and a rear wall (59) extending downward from the rear end of the rear ceiling section (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 as the rear; a first nozzle (91) provided in a region of the rear ceiling section (57) behind the center of the rear ceiling section (57) in the transport direction or on the rear wall (59), for discharging a first combustion gas forward; a second nozzle (93) provided in the rear ceiling portion (57) at a position forward of the first nozzle (91) 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 nozzle (93) based on a target air ratio in a primary combustion zone, which is a region within the furnace body (30).

[0099] With 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, promoting the combustion of the materials to be incinerated. As a result, appropriate combustion, such as low NOx emissions, can be achieved.

[0100] (2) A second aspect of the combustion equipment (1) is the combustion equipment (1) described in (1), wherein the second nozzle (93) may be provided in a region of the rear ceiling portion (57) forward of the center of the rear ceiling portion (57) in the conveying direction.

[0101] With this configuration, the second nozzle can be more appropriately installed.

[0102] (3) The 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 conveying direction.

[0103] With this configuration, the second nozzle can be more appropriately installed.

[0104] (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 forward horizontal direction is 0°.

[0105] With this configuration, the second nozzle can be more appropriately installed.

[0106] (5) A fifth aspect of the combustion equipment (1) is the combustion equipment (1) described in any one of (1) to (4), which includes the first nozzle (91) and is provided with a plurality of first nozzles (91) that are provided in an area of ​​the rear ceiling portion (57) rearward of the center of the rear ceiling portion (57) in the conveying direction or on the rear wall (59) and discharge the first combustion gas forward, and a plurality of imaginary lines are defined that respectively extend forward from the plurality of first nozzles (91), and when viewed from above, the second nozzle (93) may be arranged between the plurality of imaginary lines.

[0107] With this 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.

[0108] (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 on the rear wall (59) and may discharge the first combustion gas in a direction that forms a wall jet along the rear ceiling portion (57).

[0109] With this configuration, it is possible to promote mixing of the first combustion gas discharged from the first nozzle with the air.

[0110] (7) A seventh aspect of the combustion equipment (1) is the combustion equipment (1) described in any one of (1) to (6), and includes a detection unit (95) that detects a decrease in the oxygen concentration in the primary combustion area, and the control unit (130) may perform control to increase the oxygen concentration of the first combustion gas when the detection unit (95) detects a decrease in the oxygen concentration in the primary combustion area, and may perform control to increase the oxygen concentration of the second combustion gas when the control is performed but an increase in the oxygen concentration in the primary combustion area or a sign of such an increase is not detected.

[0111] With this configuration, the NOx concentration and the CO concentration can be optimized.

[0112] (8) The combustion equipment (1) of the eighth aspect may be the combustion equipment (1) described in any one of (1) to (7), further comprising: an angle adjustment mechanism (97) capable of changing the discharge direction of the second combustion gas from the second nozzle (93); a sensor (81) that detects components contained in the gas after the combustion or the gas that has passed through the furnace (60); and a control unit (130) that controls the angle adjustment mechanism (97) based on the detection result of the sensor (81).

[0113] With this configuration, the direction of the second combustion gas discharged from the second nozzle can be appropriately adjusted.

[0114] (9) A ninth aspect of the control method is a control method for a combustion facility (1), the combustion facility (1) comprising: a furnace (60) into which 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 target (S) while combusting the material to be incinerated (S), and in which, when the upstream side in the transport direction of the incineration target (S) is referred to as the front and the downstream side in the transport direction as the rear, the furnace body (30) has a front ceiling section (55) extending forward from the furnace (60), a rear ceiling section (57) extending rearward from the furnace (60), and a rear wall (59) extending downward from the rear end of the rear ceiling section (57); The furnace comprises: a first nozzle (91) provided in a region of the rear ceiling portion (57) rearward of the center of the rear ceiling portion (57) in the conveying direction or on the rear wall (59), and discharging a first combustion gas forward; and a second nozzle (93) provided in the rear ceiling portion (57) at a position forward of the first nozzle (91), and discharging a second combustion gas from the rear ceiling portion (57) toward the drying stage (30a) or the combustion stage (30b), wherein one or more computers (1100) control the amount of the second combustion gas discharged by the second nozzle (93) based on a target air ratio in a primary combustion zone, which is a region within the furnace body (30).

[0115] With 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, promoting the combustion of the materials to be incinerated. As a result, appropriate combustion, such as low NOx emissions, can be achieved.

[0116] According to the combustion equipment system and combustion control method of the present disclosure, appropriate combustion can be achieved.

[0117] DESCRIPTION OF SYMBOLS 1...Combustion equipment 2...Storage section 3...Incinerator 11...Waste pit 12...Crane 21...Hopper 22...Feeder 23...Extrusion device 24...Moisture meter 25...Sprinkler device 30...Furnace body 31...Inner furnace temperature sensor 32...Visible light camera 33...Infrared camera 40...Stoker 50...Wind box 51...Wind box pressure sensor 55...Front ceiling section 57...Rear ceiling section 59...Rear wall 60...Furnace 60a...Front wall 60b...Rear wall 70...Blower mechanism 71...Blower 73...Air preheater 75...Damper 81...Gas sensor 91...First EGR nozzle 93...Second EGR nozzle 95...Detection section 97...Angle adjustment mechanism 100...Control device 110...Information acquisition section 120...Flame information derivation section 130...Control section 140... Powder layer height output section S... Material to be incinerated

Claims

1. Combustion equipment comprising: a furnace into which post-combustion gas flows; 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, wherein 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, and which 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 of ​​the rear ceiling section rearward of the center of the rear ceiling section in the transport direction or on the rear wall, and which discharges 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 second combustion gas from the rear ceiling section towards the drying stage or the combustion stage; and a control unit which controls the amount of 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.

2. The combustion equipment according to claim 1, wherein the second nozzle is provided in a region of the rear ceiling portion that is forward of the center of the rear ceiling portion in the transport direction.

3. The combustion equipment according to claim 2, wherein the second nozzle is provided in the frontmost area of ​​the four virtually divided areas in the transport direction of the rear ceiling portion.

4. A combustion facility as described in any one of claims 1 to 3, wherein 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 the forward horizontal direction is 0°.

5. A combustion facility as described in any one of claims 1 to 3, which includes the first nozzle and is provided with a plurality of first nozzles which are provided in an area of ​​the rear ceiling section rearward of the center of the rear ceiling section in the conveying direction or on the rear wall and which discharge the first combustion gas forward, and which defines a plurality of imaginary lines each extending forward from the plurality of first nozzles, and when viewed from above, the second nozzle is positioned between the plurality of imaginary lines.

6. Combustion equipment as described in any one of claims 1 to 3, wherein the first nozzle is provided on the rear wall and discharges the first combustion gas in a direction that forms a wall jet along the rear ceiling portion.

7. Combustion equipment as claimed in any one of claims 1 to 3, comprising a detection unit that detects a decrease in the oxygen concentration in the primary combustion zone, wherein the control unit performs control to increase the oxygen concentration of the first combustion gas when the detection unit detects a decrease in the oxygen concentration in the primary combustion zone, and when, even after performing the above control, no increase in the oxygen concentration in the primary combustion zone or signs of such an increase are detected, the control unit performs control to increase the oxygen concentration of the second combustion gas.

8. A combustion facility as claimed in any one of claims 1 to 3, further comprising: an angle adjustment mechanism capable of changing the 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; and a control unit for controlling the angle adjustment mechanism based on the detection results of the sensor.

9. A method for controlling combustion equipment, the combustion equipment comprising: a furnace into which post-combustion gas flows; a furnace body including a drying stage, a combustion stage, and a post-combustion stage, which transports materials to be incinerated while burning them, wherein 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, the furnace body having 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 an area of ​​the rear ceiling section rearward of the center of the rear ceiling section in the transport direction or on the rear wall, which discharges first combustion gas forward; and a second nozzle provided in the rear ceiling section at a position forward of the first nozzle, which discharges second combustion gas from the rear ceiling section toward the drying stage or the combustion stage, wherein one or more computers control the amount of second combustion gas discharged by the second nozzle based on a target air ratio in a primary combustion zone, which is an area within the furnace body. A control method comprising:

Images