JP6695160B2 - Stoker incinerator - Google Patents

Description

  The present invention relates to a stoker incinerator.

  In the refuse incinerator, combustion control is performed using the planned value of the refuse quality expressed by the apparent specific gravity and the lower heating value. That is, each operation end is adjusted (controlled) according to various target values set based on the planned value of the waste quality. Further, Patent Documents 1 and 2 propose a method of determining the specific gravity of the waste by detecting the weight of the waste and the volume of the waste and controlling the combustion means of the waste based on the specific gravity. In Patent Document 3, the lower heating value of waste is calculated by detecting the combustion exhaust gas amount, the water content in the exhaust gas, the carbon dioxide gas amount, and the incineration amount, and the drying air amount and the like are automatically controlled using the lower heating value. A method of doing so is disclosed.

Japanese Patent No. 3926173 Japanese Patent No. 3928709 Japanese Patent Publication No. 61-16889

  By the way, the quality of garbage varies depending on the season and weather. Further, even if the waste has a large apparent specific gravity, the lower heating value is not necessarily small, and similarly, even if the apparent specific gravity is small, the lower heating value is not necessarily large. Therefore, the methods of Patent Documents 1 to 3 may not always maintain a preferable combustion state. Therefore, there is a demand for a new method of more reliably maintaining a preferable combustion state in accordance with fluctuating waste quality.

  The present invention has been made in view of the above problems, and an object of the present invention is to more reliably maintain a preferable combustion state in accordance with fluctuating quality of waste.

The invention according to claim 1 is a stoker-type incinerator, which has a grate portion that conveys waste along a predetermined conveyance path, and the grate portion is a drying fire in which the waste is dried. A grate, a combustion chamber having a combustion grate adjacent to the downstream side of the dry grate in the transport path, and having a combustion grate in which the combustion of the dust is performed, and air is supplied to the dust at each position of the transport path. By supplying, an air supply unit for burning the waste in the combustion chamber, and a hopper for storing the waste, and a waste supply unit for supplying the waste in the hopper onto the dry grate, and While measuring the weight of the dust thrown into the hopper, a laser distance meter capable of scanning the inside of the hopper , or a volume measuring unit that is a stereo camera, to calculate the amount of change in the volume of dust in the hopper. , By measuring the volume of the dust thrown into the hopper, the apparent specific gravity acquisition unit to obtain the apparent specific gravity of the dust, the weight of the dust, the flow rate of exhaust gas discharged from the combustion chamber, and the exhaust gas By measuring the concentration of water vapor and the concentration of carbon dioxide contained in the lower calorific value acquisition unit for acquiring the lower calorific value of the garbage, based on the apparent specific gravity and the lower calorific value, by the air supply unit An EGR gas that supplies an EGR gas containing exhaust gas discharged from the combustion chamber into the combustion chamber through two gas nozzles, and a control unit that controls a supply flow rate of air and a transportation speed of dust by the grate unit. A gas supply unit, one of the two gas nozzles ejects the EGR gas toward the vicinity of the dust on the dry grate, and the other gas nozzle is downstream from the dry grate in the transport path. The EGR gas is jetted from above the position separated to the side, the EGR gas supply unit can individually adjust the flow rate of the EGR gas jetted from the two gas nozzles, and the control unit is configured to based on the specific gravity and the lower heating value, that controls the flow rate of the EGR gas from the two gas nozzle in the EGR gas supply unit.

  The invention according to claim 2 is the stoker-type incinerator according to claim 1, wherein the air supply unit causes the air supplied to the dry grate to be higher than the temperature of the air supplied to the combustion grate. Can be adjusted to a higher temperature, and the control unit controls the temperature of the air supplied to the drying grate by the air supply unit based on the apparent specific gravity and the lower heating value.

The invention according to claim 3 is the stoker type incinerator according to claim 1 or 2 , wherein a radio wave is emitted toward the surface of dust on the dry grate, and the radio wave is reflected from the surface. By further receiving a wave, by further comprising a dust height detection unit that detects the height of the dust on the dry grate, the control unit, based on the apparent specific gravity and the lower heating value, the dry fire change the target value of the height of the dust on the grid, based on the height and the target value of the waste is obtained by the dust level detector to control the feed rate of waste by the waste feed portion In the case where the apparent specific gravity decreases or the lower heating value increases, the target value of the height of the waste is reduced and the apparent specific gravity increases or the lower heating value decreases. to, the target value of the height of the dust Ru is increased.

The invention according to claim 4 is the stoker type incinerator according to any one of claims 1 to 3 , further comprising a thermal image capturing unit configured to capture a thermal image of the dust on the grate unit, The control unit, based on the position of the ignition point or burn-out point of the dust on the grate portion obtained from the thermal image, the flow rate of air supplied by the air supply unit, or the transfer of dust by the grate unit. Control the speed.

  According to the present invention, by performing control based on both the apparent specific gravity and the lower heating value, it is possible to more reliably maintain a preferable combustion state in accordance with fluctuating quality of waste.

It is a figure which shows the structure of an incinerator. It is a figure which shows the structure of a secondary air supply part. It is a figure which shows the structure of an EGR gas supply part. It is a figure which shows the structure of a dust height detection part. It is a figure which shows the function structure of a basic control unit. It is a figure which shows the one part functional structure of a correction control unit. It is a figure which shows the other functional structure of a correction control unit. It is a figure which shows the other functional structure of a correction control unit.

  FIG. 1 is a diagram showing a configuration of an incinerator 1 according to an embodiment of the present invention. As will be described later, the incinerator 1 of FIG. 1 is a stoker-type incinerator that conveys and combusts waste, which is waste, by a plurality of grate (stoker).

  The incinerator 1 includes a combustion chamber 2, an air supply unit 3, a dust supply unit 4, an exhaust path 5, an EGR gas supply unit 6 (see FIG. 3 described later), and a control system 8. The control system 8 is responsible for overall control of the incinerator 1. In the combustion chamber 2, combustion of waste and combustion of a combustion product gas containing carbon and hydrogen generated from the waste as main components are performed. Exhaust gas (combustion gas) discharged from the combustion chamber 2 is subjected to a predetermined exhaust gas treatment in the discharge path 5 and is introduced into the atmosphere.

  The refuse supply unit 4 includes a hopper 41 and a dust supply device 42. The hopper 41 stores garbage. Waste is thrown into the hopper 41 from the waste pit by the crane 431. The crane 431 is provided with a weight scale 432, and the weight of the dust thrown into the hopper 41 is acquired. Further, the volume of dust in the hopper 41 is measured by a scannable laser range finder or a volume measuring unit 433 which is a stereo camera. In reality, every time the crane 431 throws dust into the hopper 41, the amount of change in the dust volume inside the hopper 41 is calculated, and the thrown dust volume is acquired. The control system 8 obtains the sum of the weight and the sum of the volumes of the dust thrown into the hopper 41 per unit time. In the following description, the garbage thrown into the hopper 41 within each unit time is referred to as a “trash group”, and the weight and volume of the garbage group are referred to as a “trash group weight” and a “trash group volume”.

  The dust feeding device 42 feeds the dust in the hopper 41 onto the later-described grate part 21 in the combustion chamber 2 by the pushing operation by the drive mechanism 421 such as a pusher or a screw. By controlling the drive mechanism 421, the speed of supplying dust from the dust feeder 42 onto the grate part 21 (for example, the number of extrusion operations per predetermined time, hereinafter referred to as "dust feeder speed"). Is adjustable.

  The combustion chamber 2 has a grate part 21 and a discharge part 22. The grate part 21 is provided between the dust supply device 42 and the discharge part 22 and includes a plurality of grate continuously arranged between the two. The dust on the grate portion 21 moves toward the discharge portion 22 due to the reciprocating movement of the movable grate arranged at every other grate portion. In this way, the plurality of grate of the grate part 21 conveys the dust along the conveyance path extending from the dust supply device 42 to the discharge part 22. As will be described later, air is supplied to the dust by the air supply unit 3 at each position of the transport path, and the dust burns in the combustion chamber 2. The waste (mainly ash) after combustion is discharged to the outside of the combustion chamber 2 at the discharge part 22. Various shapes, arrangements, operations, etc. of the plurality of grate in the grate portion 21 can be adopted.

  The transport path on the grate part 21 is divided into three parts in the moving direction of dust. The dust is supplied to the portion 23 on the dust feeder 42 side in the transport path by the dust feeder 42, and the dust is mainly dried in the portion 23. Dust is burned mainly in the central portion 24 of the transport path, and after-burning of the dust is mainly performed in the portion 25 on the discharge unit 22 side. In the following description, the three parts 23, 24, 25 in the transport path are referred to as the dry grate 23, the combustion grate 24 and the post-combustion grate 25, respectively. In the transport path, the combustion grate 24 is adjacent to the downstream side of the dry grate 23, and the post-combustion grate 25 is adjacent to the downstream side of the combustion grate 24. Each of the dry grate 23, the combustion grate 24, and the post-combustion grate 25 is a set of a plurality of grate.

  In the incinerator 1 of FIG. 1, the combustion grate 24 is further divided into a first combustion grate 241 and a second combustion grate 242. The post-combustion grate 25 is further divided into a first post-combustion grate 251 and a second post-combustion grate 252. A drive mechanism 26 that drives the movable grate is provided for each of the dry grate 23, the first combustion grate 241, the second combustion grate 242, and the post-combustion grate 25. In the dry grate 23, the first combustion grate 241, the second combustion grate 242, and the post-combustion grate 25, the transport speed of dust can be adjusted individually. In the following description, the transportation speed of the dust in the dry grate 23, the combustion grate 24, and the post-combustion grate 25 is referred to as “dry grate speed”, “combustion grate speed”, and “post-combustion grate speed”.

  The air supply unit 3 includes a primary air supply unit 31 and a secondary air supply unit 32 (see FIG. 2 described later). The primary air supply unit 31 includes an air preheater 311, a heated air supply pipe 312, an auxiliary air supply pipe 313, and a bypass pipe 314 (a part of which is indicated by a broken line). The air preheater 311 heats the combustion air supplied from the outside via a fan (not shown) and discharges the heated air. One end of the heated air supply pipe 312 is connected to the air preheater 311. The other end of the heated air supply pipe 312 is branched into five branch pipes 315, and the five branch pipes 315 include the dry grate 23, the first combustion grate 241, the second combustion grate 242, and the second combustion grate 242. It is connected to the first post-combustion grate 251 and the second post-combustion grate 252, respectively. Through the heated air supply pipe 312, the heated air from the air preheater 311 causes the dry grate 23, the first combustion grate 241, the second combustion grate 242, the first post combustion grate 251, and the second post combustion grate 251. You are led to 252.

  One end of the auxiliary air supply pipe 313 is connected to the heated air supply pipe 312. Unheated air is supplied to the other end of the auxiliary air supply pipe 313. As a result, air having a temperature lower than that of the heated air is mixed with the heated air, with the position 316 of the heated air supply pipe 312 to which the auxiliary air supply pipe 313 is connected as the mixing position. In the heated air supply pipe 312, a thermometer 331 is provided between the mixing position 316 and the branch pipe 315. The flow rate of the heated air discharged from the air preheater 311 (that is, the flow rate of the air supplied to the air preheater 311) and the auxiliary air supply pipe so that the output value of the thermometer 331 reaches a predetermined target temperature. The flow rate of unheated air flowing through 313 is adjusted.

  One end of the bypass pipe 314 is connected to the heated air supply pipe 312 at a position between the air preheater 311 and the mixing position 316 (hereinafter, simply referred to as a “connection position”). The other end of the bypass pipe 314 is connected to a branch pipe 315 for the dry grate 23. The bypass pipe 314 substantially connects the connection position and the dry grate 23. At the connection position, heated air that is not mixed with unheated air is flowing, and the heated air is supplied to the bypass pipe 314. Further, the bypass pipe 314 is provided with a bypass flow rate adjusting unit 332 including a damper. In the air supply unit 3, the bypass flow rate adjusting unit 332 can adjust the air supplied to the dry grate 23 to a temperature higher than the temperatures of the air supplied to the combustion grate 24 and the post-combustion grate 25. In practice, a thermometer 333 is provided in the branch pipe 315 for the dry grate 23. The flow rate of the heated air flowing through the bypass pipe 314 is adjusted by the control of the control system 8 based on the output value of the thermometer 333, and the temperature of the air supplied to the dry grate 23 (hereinafter referred to as “dry grate air temperature”). ) Is adjusted.

  A damper 334 and a flow meter 335 are provided on each branch pipe 315. The control system 8 controls the damper 334 based on the output value of the flow meter 335, so that the flow rate of the air flowing through each branch pipe 315, that is, the dry grate 23, the first combustion grate 241, and the second combustion fire. The flow rate of air supplied to each of the grate 242, the first post-combustion grate 251, and the second post-combustion grate 252 is adjusted. In the branch pipe 315 connected to the dry grate 23, the heated air flowing from the bypass pipe 314 does not flow backward due to the pressure difference and proper ducting. Of course, a check valve may be provided in the branch pipe 315. In the following description, the air supplied from the primary air supply part 31 to the grate part 21 is called “primary air”. In addition, the flow rates of the primary air supplied to the dry grate 23, the combustion grate 24, and the post-combustion grate 25, respectively, are “dry grate air flow rate”, “combustion grate air flow rate”, and “post-combustion grate air flow rate”. And the total flow rate of these is called the "primary air flow rate". The combustion grate air flow rate may be individually set in the first combustion grate 241 and the second combustion grate 242, and the post combustion grate air flow rate may also be set in the first post combustion grate 251 and the second post combustion grate. It may be set individually at 252.

  FIG. 2 is a diagram showing the configuration of the secondary air supply unit 32. The secondary air supply unit 32 includes an air preheater 321, a heated air supply pipe 322, an auxiliary air supply pipe 323, and a fan 324. The air preheater 321 heats the combustion air supplied via the fan 324 and discharges the heated air. One end of the heated air supply pipe 322 is connected to the air preheater 321. The other end of the heated air supply pipe 322 is branched into two branch pipes 325, and the two branch pipes 325 are connected to a front wall side secondary air nozzle 326 and a rear wall side secondary air nozzle 327, respectively. .. The heated air from the air preheater 321 is guided to the front wall side secondary air nozzle 326 and the rear wall side secondary air nozzle 327 by the heated air supply pipe 322. The arrangement of the front wall side secondary air nozzle 326 and the rear wall side secondary air nozzle 327 in the combustion chamber 2 will be described later.

  One end of the auxiliary air supply pipe 323 is connected to the heated air supply pipe 322. The other end of the auxiliary air supply pipe 323 is connected to the pipe between the fan 324 and the air preheater 321. The auxiliary air supply pipe 323 mixes the unheated air with the heated air flowing through the heated air supply pipe 322. In the heated air supply pipe 322, a thermometer 341 is provided between the branch pipe 325 and the position where the auxiliary air supply pipe 323 is connected. The flow rate of the heated air discharged from the air preheater 321 (that is, the flow rate of the air supplied to the air preheater 321) and the auxiliary air supply pipe so that the output value of the thermometer 341 reaches the predetermined target temperature. The flow rate of unheated air flowing through 323 is adjusted.

  Further, a damper 342 and a flow meter 343 are provided on each branch pipe 325. The control system 8 controls the damper 342 based on the output value of the flow meter 343, whereby the flow rate of the air flowing through each branch pipe 325, that is, the front wall side secondary air nozzle 326 and the rear wall side secondary air nozzle. The flow rate of air ejected from 327 can be adjusted individually. In the following description, the air supplied from the secondary air supply unit 32 to the front wall side secondary air nozzle 326 and the rear wall side secondary air nozzle 327 is referred to as “secondary air”, and the total flow rate of the secondary air is This is called "secondary air flow rate".

  FIG. 3 is a diagram showing the configuration of the EGR gas supply unit 6. The EGR gas supply unit 6 includes an EGR gas supply pipe 61 and a fan 62. At one end of the EGR gas supply pipe 61, a gas containing exhaust gas discharged from the combustion chamber 2 (that is, exhaust gas recirculation gas, which is hereinafter referred to as “EGR gas”) is passed through a fan 62. Supplied. The EGR gas is, for example, a mixture of exhaust gas that has passed through a bag filter (not shown) provided in the exhaust path 5 and air. The EGR gas may be a gas containing only the exhaust gas. That is, the EGR gas contains at least exhaust gas.

  The other end of the EGR gas supply pipe 61 is branched into two branch pipes 63, and the two branch pipes 63 are respectively connected to two gas nozzles, that is, a front wall side EGR gas nozzle 64 and a rear wall side EGR gas nozzle 65. To be done. A damper 66 and a flow meter 67 are provided in each branch pipe 63. The control system 8 controls the damper 66 based on the output value of the flow meter 67, so that the flow rate of the EGR gas flowing through each branch pipe 63, that is, the combustion from the front wall side EGR gas nozzle 64 and the rear wall side EGR gas nozzle 65. The flow rate of the EGR gas ejected (supplied) into the chamber 2 can be individually adjusted. In the following description, the flow rates of the EGR gas ejected from the front wall side EGR gas nozzle 64 and the rear wall side EGR gas nozzle 65 are referred to as the “front wall side EGR gas flow rate” and the “rear wall side EGR gas flow rate”, respectively, and The flow rate is called "EGR gas flow rate".

  In the combustion chamber 2 shown in FIG. 1, a front wall portion 201 that roughly covers the upper portion of the dry grate 23 and a rear wall portion 202 that roughly covers the upper portion of the post combustion grate 25 are provided. The front wall side secondary air nozzle 326 and the front wall side EGR gas nozzle 64 are individually provided in the front wall portion 201. In FIG. 1, the front wall side secondary air nozzle 326 and the front wall side EGR gas nozzle 64 are indicated by one arrow A1. The rear wall side secondary air nozzle 327 and the rear wall side EGR gas nozzle 65 are individually provided in the rear wall portion 202. In FIG. 1, the rear wall side secondary air nozzle 327 and the rear wall side EGR gas nozzle 65 are indicated by one arrow A2.

  In the combustion chamber 2, the secondary air is supplied (jetted) from the front wall side secondary air nozzle 326 and the rear wall side secondary air nozzle 327 to the gas flowing toward the exhaust path 5. As a result, the unburned gas generated in the combustion chamber 2 burns. Further, the EGR gas is ejected from the front-wall-side EGR gas nozzle 64 toward the vicinity of the dust on the dry grate 23, and the rear-wall-side EGR gas nozzle 65 causes the EGR gas to rise above the position separated from the dry grate 23 to the downstream side in the transport path. From, the EGR gas is ejected into the combustion chamber 2. By supplying the EGR gas into the combustion chamber 2, the combustion temperature is lowered. As a result, generation of thermal NOx (nitrogen oxide) is suppressed, and NOx concentration is reduced.

  A boiler 711 that uses exhaust gas as a heat source is provided above the combustion chamber 2. The steam from the boiler 711 is further heated by the superheater 712 that uses the exhaust gas, and superheated steam is generated. The flow rate of the superheated steam discharged from the superheater 712 (hereinafter, referred to as “boiler generated steam amount”) is measured by a flow meter 713. The superheated steam is used, for example, for power generation.

  Inside the combustion chamber 2, a plurality of thermometers 721 and 722, a dust layer thickness acquisition unit 73, a dust height detection unit 74, and a thermal image capturing unit 75 are further provided. The plurality of thermometers 721 and 722 are, for example, thermocouple thermometers. The one thermometer 721 is located in the combustion chamber 2 in the vicinity of the connecting portion with the discharge path 5, that is, in the vicinity of the outlet of the combustion chamber 2. The temperature acquired by the thermometer 721 is hereinafter referred to as "combustion chamber outlet temperature". The other thermometer 722 is located above the post-combustion grate 25 in the combustion chamber 2. Hereinafter, the temperature acquired by the thermometer 722 will be referred to as "upper combustion grate upper temperature". Another thermometer may be provided in the combustion chamber 2.

  The dust layer thickness acquisition unit 73 has two pressure gauges. One pressure gauge acquires the pressure above the combustion grate 24 in the combustion chamber 2, and the other pressure gauge acquires the pressure below the combustion grate 24 (branch pipe 315 side). The differential pressure between the two pressures obtained by the two pressure gauges depends on the amount (thickness) of dust existing on the combustion grate 24. In the dust layer thickness acquisition unit 73, the thickness of the dust layer on the combustion grate 24 (an estimated value of the thickness, based on the differential pressure, the supply amount of primary air to the combustion grate 24, and the like, Hereinafter, “calculated waste layer thickness”) is acquired.

  The thermal image capturing section 75 is attached to the rear wall section 202, for example, and captures a thermal image of dust on the grate section 21. The thermal image capturing unit 75 is an infrared camera, and has maximum sensitivity at a wavelength of 3.9 micrometers (μm), for example. The thermal image capturing unit 75 is provided with a cooling mechanism, and a thermal image of dust on the grate part 21 (hereinafter, referred to as “IR thermal image”) is stably acquired during operation of the incinerator 1. The IR thermal image is a thermal image in which the influence of a luminous flame is removed by a predetermined process, and the combustion state of dust in the combustion chamber 2 (specifically, the surface temperature) can be accurately grasped. As described later, the IR thermal image is used to detect the burning position of dust on the grate portion 21. In the incinerator 1, a plurality of thermal image capturing units 75 may be provided.

  FIG. 4 is a diagram showing a configuration of the dust height detection unit 74. In FIG. 4, the dust height detection unit 74 is shown in an enlarged manner. The dust height detection unit 74 is provided on the front wall portion 201 and includes a measurement unit 741 and an annular nozzle 742. The measuring unit 741 is arranged above the dust 9 on the dry grate 23 and includes a transmitter and a receiver. The transmitter antenna and the receiver antenna are provided on a common measuring surface 743. The transmitter and receiver may share an antenna. In the measurement unit 741, a microwave band radio wave is emitted from the measurement surface 743 toward the surface of the dust 9 on the dry grate 23, and a reflected wave of the radio wave from the surface of the dust 9 is received by the measurement surface 743. .. As a result, the height of the dust 9 on the dry grate 23 (hereinafter referred to as “dry grate dust height”) is detected. In particular, the measuring unit 741 obliquely detects the level of the upper portion of the dust 9 on the dry grate 23 so that the dust 9 can be stably supplied to the dry grate 23. Is preferred. The dust height detecting unit 74 may use radio waves in the millimeter wave band.

  The annular nozzle 742 is an annular shape that surrounds the circumference of the measurement unit 741 and has an annular ejection port. The annular ejection port constantly ejects the purging gas. The purging gas ejected from each part of the annular ejection port collides with the purging gas ejected from another part of the annular ejection port at the focal point in the vicinity of the measurement surface 743. As a result, the measurement surface 743 is arranged in the space surrounded by the flow of the purging gas. The purging gas is preferably EGR gas containing exhaust gas. In the dust height detection unit 74, the measuring surface 743 is prevented from being contaminated by the purging gas, and the dry grate dust height is stably and accurately detected. The annular nozzle 742 also serves as a part of the heat insulating unit, and the heat insulating unit suppresses damage to the measuring unit 741 due to heat.

As shown in FIG. 1, an oxygen concentration meter 51, a concentration measurement unit 52, and a flow meter 53 are provided in the discharge path 5. The oxygen concentration meter 51 is provided near the combustion chamber 2 in the exhaust path 5. The oxygen concentration meter 51 measures the oxygen concentration (hereinafter, referred to as “combustion chamber outlet oxygen concentration”) using laser light. The concentration measuring unit 52 and the flowmeter 53 are provided on the downstream side of the bag filter (not shown), that is, between the bag filter and the chimney. The concentration measuring unit 52 measures the concentration of water vapor and the concentration of carbon dioxide contained in the exhaust gas (hereinafter referred to as “exhaust gas moisture concentration” and “exhaust gas CO ₂ concentration”). The flowmeter 53 measures the flow rate of exhaust gas.

  FIG. 5 is a diagram showing a functional configuration of the basic control unit 81 included in the control system 8. The basic control unit 81 includes a steam amount control unit 811, an incineration amount calculation unit 812, an incineration amount control unit 813, a combustion chamber temperature control unit 814, an oxygen concentration control unit 815, and an ablation reduction control unit 816. A combustion position control unit 817 and a dust layer thickness control unit 818 are provided. FIG. 5 also shows the types of values input to the respective control units of the basic control unit 81 and the types of values (operation parameters) commanded (output) by the control units. In each control unit of the basic control unit 81, the command value of each operation parameter is constantly adjusted based on the input value. The operation of the control system 8 described below is an example, and may be appropriately changed. When the operation parameters are duplicated in the plurality of control units included in the basic control unit 81, the weights (which may be different for each operation parameter) respectively determined for the plurality of control units are considered. Thus, the actual command value of the operation parameter is determined.

  The steam amount control unit 811 performs an operation to approximate the boiler generated steam amount to a target steam amount described later. For example, when the amount of steam generated by the boiler is larger than the target amount of steam, the command value of the refuse feed reference speed is reduced from the current value. Here, the command value of the refuse feed reference speed is a reference value in the calculation of the command value of the dust feeder speed, the command value of the dry grate speed, the command value of the combustion grate speed, and the command value of the post combustion grate speed. It will be. When the command value of the refuse feed reference speed is reduced, the command value of the dust feeder speed, the command value of the dry grate speed, the command value of the combustion grate speed, and the command value of the post-combustion grate speed become smaller. When the amount of steam generated by the boiler is smaller than the target amount of steam and the command value of the refuse feed reference speed is increased, the dust collector speed command value, the dry grate speed command value, the combustion grate speed command value, and The post-combustion grate velocity command value increases.

  When the amount of steam generated by the boiler is larger than the target amount of steam, the command value of the primary air flow rate is reduced from the current value and the command value of the secondary air flow rate is increased from the current value. The command value of the primary air flow rate serves as a reference for calculating the command value of the dry grate air flow rate, the command value of the combustion grate air flow rate, and the command value of the post-combustion grate air flow rate. As the command value of the primary air flow rate increases or decreases, the command value of the dry grate air flow rate, the command value of the combustion grate air flow rate, and the command value of the post-combustion grate air flow rate also increase or decrease. The command value of the secondary air flow rate is a command value of the total flow rate of the air supplied from the secondary air supply unit 32 to the front wall side secondary air nozzle 326 and the rear wall side secondary air nozzle 327.

  The total amount of the primary air flow rate and the secondary air flow rate is defined as the reference air amount, and the change of the command value of the primary air flow rate and the command value of the secondary air flow rate is the change of the ratio of each flow rate to the reference air amount ( The same applies below). When the amount of steam generated by the boiler is smaller than the target amount of steam, the command value of the primary air flow rate is increased from the current value and the command value of the secondary air flow rate is reduced from the current value.

  In the incineration amount calculation unit 812, the weight of the waste supplied from the waste supply unit 4 onto the dry grate 23 per unit time is obtained as the actual incineration amount. The actual incineration amount is obtained, for example, by obtaining the volume of dust supplied on the grate unit 21 per unit time based on the measurement value of the volume measuring unit 433 and multiplying the volume by an apparent specific gravity described later. The incineration amount control unit 813 is configured to be activated in the incineration amount constant control described later, and the details will be described later.

  In the combustion chamber temperature control unit 814, when the combustion chamber outlet temperature is higher than the preset set outlet temperature, the command value of the EGR gas flow rate is set so that the combustion chamber outlet temperature approximates the set outlet temperature. The command value of the EGR gas flow rate is decreased from the current value when the combustion chamber outlet temperature is increased from the value and the combustion chamber outlet temperature is lower than the set outlet temperature. In the oxygen concentration control unit 815, when the combustion chamber outlet oxygen concentration is higher than a preset outlet concentration, the command value of the secondary air flow rate is reduced from the current value, and the command value of the primary air flow rate is changed to the current value. Increased from the value. When the oxygen concentration in the outlet of the combustion chamber is smaller than the set outlet concentration, the command value of the secondary air flow rate is increased from the current value and the command value of the primary air flow rate is reduced from the current value.

  In the thermal ablation reduction control unit 816, when the post combustion grate upper temperature is higher than the preset upper temperature, the command value of the post combustion grate air flow rate is increased from the current value, and the post combustion grate velocity is increased. The command value of is reduced from the current value. When the post-combustion grate upper temperature is lower than the set upper temperature, the command value of the post-combustion grate air flow rate is reduced from the current value, and the post-combustion grate velocity command value is increased from the current value. In the combustion position control unit 817, when the post combustion grate upper temperature is higher than the set upper temperature, the dry grate velocity command value, the combustion grate velocity command value, and the post combustion grate velocity command value Each is reduced from the current value. If the post combustion grate upper temperature is lower than the set upper temperature, the dry grate velocity command value, the combustion grate velocity command value, and the post combustion grate velocity command value increase from the current values. To be done.

  In the dust layer thickness control unit 818, when the calculated dust layer thickness is larger than the target dust layer thickness, the dust collector speed command value, the dry grate speed command value, and the combustion grate speed command value Each is reduced from the current value. The target dust layer thickness is determined according to the target incineration amount and the like described later. When the calculated dust layer thickness is smaller than the target dust layer thickness, each of the dust feeder speed command value, the dry grate speed command value, and the combustion grate speed command value is increased from the current value. .. In this way, the transport speed of dust by the grate portion 21 is controlled based on the calculated dust layer thickness.

  FIG. 6 is a diagram showing a partial functional configuration of the correction control unit 82 included in the control system 8. The correction control unit 82 performs control (correction control) in addition to the control operation of the basic control unit 81. The correction control unit 82 includes a dust quality calculation unit 821 and a dust quality correction control unit 822. The dust quality calculation unit 821 obtains the apparent specific gravity (here, specific gravity for water) of each dust group based on the dust group weight and the dust group volume. As will be described later, the apparent specific gravity of the waste group is used for calculating various reference values and the like. In the incinerator 1, the weight scale 432 for obtaining the weight of the refuse group, the volume measuring unit 433 for obtaining the volume of the refuse group, the refuse quality calculator 821, etc. realize an apparent specific gravity obtaining unit for obtaining the apparent specific gravity of the refuse. It

In addition, the dust quality calculation unit 821 calculates the lower heating value of dust. Here, the calculation of the lower heating value will be described. In the calculation of the lower heating value, for example, the method described in Japanese Patent Publication No. 61-16889 is used. Here, assuming that the flow rate of exhaust gas per unit time is G and the weight of the waste supplied on the grate part 21 per unit time is Q, the exhaust gas amount per 1 kg (kg) of waste is (G / Q) Shall be given. Assuming that the concentration of carbon dioxide gas contained in the exhaust gas is C (CO ₂ ) [%], the amount V (CO ₂ ) of carbon dioxide gas per 1 kg of waste is represented by Formula 1.

(Equation 1)
V (CO ₂ ) = (C (CO ₂ ) / 100) × (G / Q)

Further, assuming that the concentration of water vapor contained in the exhaust gas is C (H ₂ O) [%], the water vapor amount V (H ₂ O) per 1 kg of waste is expressed by Formula 2.

(Equation 2)
V (H ₂ O) = (C (H ₂ O) / 100) × (G / Q)

When the ratio of carbon in the elemental composition of the combustibles in the waste is R _C and the weight percent concentration of the combustibles in the waste is B, the carbon dioxide gas amount V (CO ₂ ) per 1 kg of the waste is expressed by Formula 3. It

(Equation 3)
V (CO ₂ ) = ( _{RC /} 100) × ( _{B /} 100) × (22.4 / 12)
= 1.87 × 10 ⁻⁴ × R _C B

On the other hand, when the ratio of hydrogen in the elemental composition of the combustible components in the waste is R _H , the amount V ′ (H ₂ O) of water vapor due to hydrogen in the combustible components in the waste is represented by Formula 4.

(Equation 4)
V ′ (H ₂ O) = ( _{RH /} 100) × ( _{B /} 100) × (22.4 / 2.016)
= 1.111 × 10 ⁻³ × R _H B

When the weight percent concentration of water in the waste is W, the water vapor amount V ″ (H ₂ O) resulting from the water is expressed by the equation 5.

(Equation 5)
V ″ (H ₂ O) = (W / 100) × (22.4 / 18)
= 1.244 x 10 ^-2 x W

Therefore, the amount of water vapor V (H ₂ O) per 1 kg of waste is represented by the equation 6.

(Equation 6)
V (H ₂ O) = 1.111 × 10 ⁻³ × _RH B + 1.244 × 10 ⁻² × W

  The weight percent concentration B of the combustible components of the waste from the expression 3 is expressed by the expression 7.

(Equation 7)
B = 5.35 × 10 ³ × V (CO ₂ ) / _RC

  In addition, the weight percent concentration W of the water content in the waste is expressed by Expression 8 from Expressions 6 and 7.

(Equation 8)
W = 80.4 × V (H ₂ O) −478 × ( _RH / _RC ) × V (CO ₂ ).

  The lower heating value Hu per 1 kg of waste is expressed by Equation 9.

(Equation 9)
Hu = 50 × B-6 × W

Therefore, the flow rate G of the exhaust gas per unit time at a certain time, the exhaust gas moisture concentration C (H ₂ O), the exhaust gas CO ₂ concentration C (CO ₂ ) and the unit time are supplied to the grate part 21. The lower heating value Hu is calculated (estimated) from the equations 1, 2, 7, 8 and 9 by using the weight Q of rubbish (the above-mentioned actual incineration amount). As the carbon ratio R _C and the hydrogen ratio R _H in the elemental composition of the combustible components in the waste, the values obtained by prior analysis or the like are used. In the incinerator 1, a weight scale 432 for acquiring the weight of the waste, a flow meter 53 for acquiring the flow rate of the exhaust gas, a concentration measuring unit 52 for acquiring the concentration of water vapor and carbon dioxide contained in the exhaust gas, and the quality of the waste. The calculation unit 821 and the like implement a low-level heat generation amount acquisition unit that acquires the low-level heat generation amount of dust.

  At the waste quality calculation unit 821, the average value of the lower heating value and the average value of the apparent specific gravity of the waste group corresponding to the lower heating value obtained at each time within the latest predetermined period are used at that time. Low calorific value and apparent specific gravity (hereinafter referred to as “target low calorific value” and “target apparent specific gravity”, respectively). The target apparent specific gravity may be an average value of the apparent specific gravities acquired within the latest predetermined period. In addition, it is preferable that the apparent specific gravity and the lower heating value that are obtained are matched with those of the dust group corresponding to the lower heating value by considering the time difference according to the dust feeder speed. In this way, by obtaining the moving average value of the lower heating value and the apparent specific gravity, it is possible to grasp the medium- and long-term fluctuations of the quality of the waste (season, collection date, fluctuations due to the weather, etc.) and perform the correction control described later. It becomes possible to perform with high accuracy. In addition, even if the lower heating value or the apparent specific gravity becomes an abnormal value, it is possible to suppress rapid fluctuations in the target lower heating value and the target apparent specific gravity (and various reference values calculated using these values). You can From the viewpoint of understanding medium- to long-term fluctuations in waste quality, the target lower heating value and target apparent specific gravity at each time are processed slightly before the waste actually processed at that time. It is not a problem that the value is based on garbage.

  In the dust quality correction control unit 822, for example, when performing control for making the boiler generated steam amount constant with a set steam amount preset by the user (steam amount constant control), the set steam amount, the target lower heating value Using the target apparent specific gravity, the reference value of the refuse feed reference speed, the reference value of the primary air flow rate, and the reference value of the secondary air flow rate to be used in the current control are calculated and updated. In the constant steam amount control, the set steam amount becomes the target steam amount.

  In an example of calculation of various reference values and the like, the total amount of heat is obtained by multiplying the set amount of steam by a predetermined conversion coefficient, and the target amount of incineration is obtained by dividing the total amount of heat by the target lower heating value. Further, the reference value of the refuse feed reference speed is obtained by dividing the target incineration amount by the target apparent specific gravity and further dividing by the predetermined conversion coefficient. When the reference value of the new (post-update) waste feed reference speed increases or decreases from the immediately preceding (pre-update) reference value of the waste feed reference speed, the command value of the waste feed reference speed also increases or decreases.

  Further, the reference air amount is obtained by multiplying the total heat amount by a value obtained by inputting the target lower heating value into a predetermined function. Then, the reference value of the primary air flow rate and the reference value of the secondary air flow rate are obtained by multiplying the reference air amount by two values obtained by inputting the target lower heating value into the other two functions. The two values indicate the ratio of the primary air flow rate and the secondary air flow rate in the reference air amount. When the reference value of the primary air flow rate after the update increases or decreases from the reference value before the update, the command value of the primary air flow rate also increases or decreases (same for the secondary air flow rate). The reference air amount may be kept constant, and only the ratio of the primary air flow rate and the secondary air flow rate may be changed based on the target lower heating value and the target apparent specific gravity. The various reference values and the like may be obtained by various calculations as long as the target lower heating value and the target apparent specific gravity are used.

  When the current target low calorific value is larger than the immediately preceding target lower calorific value or the current target apparent specific gravity is smaller than the immediately preceding target apparent specific gravity, the dust feeding device is updated by updating the reference value of the waste feed reference speed. The velocity command value, the dry grate velocity command value, the combustion grate velocity command value, and the post-combustion grate velocity command value become lower (than the current value). Further, by updating the reference value of the primary air flow rate and the reference value of the secondary air flow rate, the command value of the primary air flow rate becomes low and the command value of the secondary air flow rate becomes high. When the target lower heating value or the target apparent specific gravity fluctuates in the opposite direction to the above, the command value of each operation parameter fluctuates in the opposite direction to the above (the same applies hereinafter).

  In the dust quality correction control unit 822, further, a dry grate air flow rate command value, a combustion grate air flow rate command value, a dry grate air temperature command value, a front wall side EGR gas flow rate command value, a rear wall side. The command value of the EGR gas flow rate and the target dust layer thickness are also changed. When the current target low calorific value is larger than the immediately preceding target lower calorific value or the current target apparent specific gravity is smaller than the immediately preceding target apparent specific gravity, the command value of the dry grate air flow rate and the EGR gas on the front wall side The command value of the flow rate and the target dust layer thickness are reduced, and the command value of the combustion grate air flow rate, the command value of the dry grate air temperature, and the command value of the rear wall side EGR gas flow rate are increased.

  The change of the command value of the dry grate air flow rate and the command value of the combustion grate air flow rate is the change of the ratio of each flow rate to the command value of the primary air flow rate (the change of the command value of the post combustion grate air flow rate. Same as in). The change of the command value of the front wall side EGR gas flow rate and the command value of the rear wall side EGR gas flow rate is also a change of the ratio of each flow rate to the command value of the EGR gas flow rate. If the current target low calorific value is larger (smaller) than the previous target lower calorific value and the current target apparent specific gravity is larger (smaller) than the immediately preceding target apparent specific gravity, the target low calorific value and the target apparent amount The command value for each operation parameter is determined in consideration of the weights (which may be different for each operation parameter) determined for the specific gravity.

  The refuse quality correction control unit 822 may perform control (constant amount of incineration constant control) to make the actual amount of incineration constant with a set amount of incineration preset by the user. In this case, the incineration amount control unit 813 of FIG. 5 is activated. Then, the value obtained by integrating the actual incineration amount in the latest set period is compared with the value obtained by integrating the set incineration amount. When the integrated value of the actual incineration amount is smaller than the integrated value of the set incineration amount, the actual incineration amount increases, and when the integrated value of the actual incineration amount is larger than the integrated value of the set incineration amount. The target steam amount in the steam amount control unit 811 is changed so that the actual incineration amount is reduced. By reducing the target steam amount, the command value of the refuse feed reference speed is reduced from the current value, and by increasing the target steam amount, the dust feed reference speed command value is increased from the current value. Further, the target value of the refuse feed reference speed, the reference value of the primary air flow rate, and the reference value of the secondary air flow rate are calculated using the target steam amount, the target lower heating value, and the target apparent specific gravity. When the current target low calorific value fluctuates from the immediately preceding target low calorific value, or when the current target apparent specific gravity varies from the immediately preceding target apparent specific gravity, the fluctuation of the command value of each operation parameter is the same as in FIG. 6. is there.

  As described above, in the incinerator 1, the reference value of the refuse feed reference speed and the reference value of the primary air flow rate are obtained based on the target apparent specific gravity and the target lower heating value. Then, based on these reference values, the transport speed of dust by the grate portion 21 and the flow rate of air supplied by the air supply portion 3 to the dust on the grate portion 21 are controlled. In this way, by performing control based on both the target apparent specific gravity and the target low-order calorific value, it is possible to more reliably maintain a preferable combustion state in accordance with the quality of waste that fluctuates in the medium to long term. As a result, stable low air ratio combustion can be realized, and the generation of NOx, CO (carbon monoxide), and dioxins in exhaust gas can be reduced. In addition, the efficiency of power generation is improved, the amount of chemicals related to exhaust gas treatment is reduced, the life of the boiler 711 is extended by suppressing the abnormal temperature rise in the combustion chamber 2, and the life cycle cost (LCC) of the incinerator 1 is minimized. can do.

  Further, the temperature of the air supplied to the dry grate 23 (dry grate air temperature) by the air supply unit 3 is controlled based on the target apparent specific gravity and the target lower heating value. As a result, the dust on the dry grate 23 can be appropriately dried in accordance with the varying quality of the dust, and a preferable combustion state can be more surely maintained.

  In the primary air supply unit 31 of FIG. 1, the heated air from the air preheater 311 is guided to the dry grate 23 and the combustion grate 24 via the heated air supply pipe 312, and the mixing position 316 of the heated air supply pipe 312. At, air having a lower temperature than the heated air is mixed with the heated air. Further, in the heated air supply pipe 312, a position between the air preheater 311 and the mixing position 316 is connected to the dry grate 23 by a bypass pipe 314. Then, the dry grate air temperature is adjusted by controlling the bypass flow rate adjusting unit 332 based on the target apparent specific gravity and the target lower heating value. With such a structure, in the air supply unit 3, the dust is appropriately dried in the dry grate 23, and the number of the air preheaters 321 (as compared with the case where the air preheaters 321 are provided in the respective branch pipes 315) is reduced. Therefore, the manufacturing cost of the incinerator 1 can be reduced.

  By the way, if the dry grate air flow rate is excessively increased, dust in the hopper 41 may be ignited (backfire), so that there is a certain limit to the increase of the dry grate air flow rate. On the other hand, in the incinerator 1, the flow rate of EGR gas from the front wall side EGR gas nozzle 64 and the rear wall side EGR gas nozzle 65 is also controlled based on the target apparent specific gravity and the target lower heating value. Further, in the EGR gas, the amount of radiation of the high temperature combustion gas is adjusted to increase or decrease the radiant heat to the dust on the dry grate 23 to control the dry condition of the dust. As a result, it is possible to appropriately dry the dust on the dry grate 23 while suppressing the occurrence of flashback. Further, it is also possible to prevent the amount of air supplied into the combustion chamber 2 from increasing excessively. In the EGR gas supply unit 6, EGR gas may be supplied into the combustion chamber 2 via three or more EGR gas nozzles.

  FIG. 7 is a diagram showing another functional configuration of the correction control unit 82. The correction control unit 82 includes an ignition point position calculation unit 823, an ignition point control unit 824, a burn-off point position calculation unit 825, and a burn-off point control unit 826. The ignition point position calculation unit 823 obtains the position of the ignition point of the dust based on the IR thermal image. The ignition point control unit 824 performs feedback control based on the position of the ignition point. For example, when the position of the ignition point is on the upstream side of the preset ignition point position, that is, on the dust supply device 42 side, the command value of the rear wall side EGR gas flow rate is increased and the command of the dry grate air temperature is increased. Value, the front wall side EGR gas flow rate command value, and the dry grate air flow rate command value are reduced. By reducing the command value of the dry grate air temperature, the command value of the front wall side EGR gas flow rate, and the command value of the dry grate air flow rate, the drying of dust in the dry grate 23 is suppressed, and the position of the ignition point is located downstream. Move to the side. Further, when the position of the ignition point is on the downstream side of the set ignition point position, that is, on the discharge portion 22 side, the command value of the rear wall side EGR gas flow rate is reduced, and the command value of the dry grate air temperature and the front wall side are reduced. The command value of the EGR gas flow rate and the command value of the dry grate air flow rate are increased. As a result, the drying of dust on the dry grate 23 is promoted, and the position of the ignition point moves to the upstream side.

  Further, the burn-out point position calculation unit 825 obtains the position of the burn-out point of the dust based on the IR thermal image. The burn-out point control unit 826 performs feedback control based on the position of the burn-out point. For example, when the position of the burn-out point is upstream of the preset burn-out point position, the dust feeder speed command value, the dry grate speed command value, the combustion grate speed command value , And the command value of the post-combustion grate speed is increased (that is, the command value of the refuse feed reference speed is increased), and the command value of the post-combustion grate air flow rate is reduced. By reducing the command value of the post-combustion grate air flow rate, the combustion of dust in the post-combustion grate 25 is suppressed, and the position of the burn point moves to the downstream side. Further, when the burn-out point position is on the downstream side of the set burn-out point position, the dust feeder speed command value, the dry grate speed command value, the combustion grate speed command value, and the rear The command value for the combustion grate velocity is reduced and the command value for the post-combustion grate air flow rate is increased. The increase of the command value of the post combustion grate air flow rate promotes the combustion of dust in the post combustion grate 25, and the position of the burn point moves to the upstream side. Further, similarly to the ignition point control unit 824, the front wall side EGR gas flow rate and the rear wall side EGR gas flow rate are also controlled based on the position of the burnout point.

  Here, assume an incinerator of a comparative example in which the correction control unit 82 of FIG. 7 is omitted. As described above, in the basic control unit 81 of FIG. 5, the combustion position control unit 817 controls the combustion position based on the upper temperature of the post combustion grate. However, it is difficult to stably control the combustion position only by referring to the upper temperature of the post combustion grate. Specifically, when the quality of dust fluctuates, combustion control is delayed, and in particular, the position of the ignition point of dust becomes unstable. As a result, in the incinerator of the comparative example, the amount of steam generated in the boiler may fluctuate, and the unburned substances may increase due to the combustion position moving to the downstream side.

  On the other hand, in the incinerator 1 including the correction control unit 82 of FIG. 7, the position of the dust ignition point on the grate part 21 is quickly acquired from the IR thermal image, and the air supply is performed based on the position of the dust ignition point. The bypass flow rate adjusting unit 332 of the unit 3 is controlled (that is, the dry grate air temperature is controlled). As a result, the control for keeping the position of the ignition point of the dust constant can be performed stably and accurately. The position of the dust ignition point is also controlled by controlling the front wall EGR gas flow rate, the rear wall side EGR gas flow rate, and the dry grate air flow rate based on the position of the dust ignition point on the grate portion 21. It is possible to perform the control for maintaining the constant value with higher accuracy. Further, based on the position of the burn-out point of the dust on the grate portion 21 acquired from the IR thermal image, the dust feeder speed, the dry grate speed, the combustion grate speed, the post-combustion grate speed, the front wall side. By controlling the EGR gas flow rate, the rear wall side EGR gas flow rate, and the post-combustion grate air flow rate, it is possible to accurately control the position of the burn-out point of dust to be constant.

  In this way, by maintaining the positions of the ignition point and burn-out point of the dust at a constant level, the amount of steam generated by the boiler is stabilized, the amount of unburned substances is reduced, and the amount of NOx and CO generated in the exhaust gas in low air ratio combustion is reduced. Therefore, it is possible to stabilize the temperature in the combustion chamber 2. In practice, the operations of the ignition point control unit 824 and the burn-out point control unit 826 also make it possible to stabilize the control of the combustion position based on the post combustion grate upper temperature by the combustion position control unit 817.

  In the incinerator 1, the command value of each operation parameter may be changed according to the moving speed and direction of the dust ignition point and the burnout point, or the moving acceleration and direction. Further, the transportation speed of the dust by the grate portion 21 may be controlled based on the position of the ignition point of the dust. As described above, in the incinerator 1, the air supply flow rate of the air by the air supply section 3 (in the above example, the dry grate air flow rate or The post-combustion grate air flow rate) or the speed of transporting dust by the grate part 21 is controlled.

  FIG. 8 is a diagram showing another functional configuration of the correction control unit 82. The correction control unit 82 includes a target dust height correction unit 827 and a dust height control unit 828. As described above, the target dust layer thickness is changed (updated) by the waste quality correction control unit 822 of FIG. 6 based on the target lower heating value and the target apparent specific gravity. The target waste layer thickness after updating is input to the target waste height correcting unit 827, and when it becomes larger than the value before updating, the height of the waste on the dry grate 23 (that is, the dry grate waste height). The target waste height, which is the target value of, is increased from the current value. When the target dust layer thickness after updating is smaller than the value before updating, the target dust height is reduced below the current value.

  In the dust height control unit 828, when the dry grate dust height detected by the dust height detection unit 74 is larger than the target dust height, the dry grate dust height is approximated to the target dust height. , The command value of the dust feeder speed, the command value of the dry grate speed, and the command value of the combustion grate speed are reduced (from the current value). Similarly, when the dry grate dust height is smaller than the target dust height, the dust feeder speed command value, the dry grate speed command value, and the combustion grate speed command value are increased. Typically, the ratio of the dust feeder speed command value, the dry grate speed command value, and the combustion grate speed command value is constant, but depending on the characteristics of the dust feeder 42, the ratio is It may be changed. For example, when the dry grate dust height is smaller than the target dust height, the rate of increase of the dust collector speed command value may be set higher than the other command values.

  In the incinerator 1, since the dust height detecting unit 74 is provided above the dust on the dry grate 23 in the combustion chamber 2 (see FIG. 4), the clinker is not affected, and the like. The height of dust on the dry grate 23 can be detected accurately and stably. Further, in the dust height detecting unit 74, the purging gas is ejected from the circumference of the measurement surface 743 that emits radio waves and receives reflected waves by the annular nozzle 742. As a result, it is possible to prevent the measurement surface 743 from being soiled by dust, and it is possible to more accurately detect the height of dust on the dry grate 23. Since the purging gas is the EGR gas, it is possible to prevent the air from being excessively supplied into the combustion chamber 2 and more reliably realize the low air ratio combustion. Depending on the design of the incinerator 1, the purging gas may be nitrogen gas or may contain air.

  Further, the dust supply speed (dust feeder speed) by the dust supply unit 4 is controlled based on the height of the dry grate dust. Therefore, even if the amount of waste supplied by the waste supply unit 4 is temporarily excessive or insufficient due to fluctuations in the waste quality, the density of the waste in the hopper 41, etc., the speed of the dust collector (and the dry grate). It is possible to rapidly change the speed) to suppress a rapid change in the combustion state due to excess or deficiency of dust in the grate portion 21, particularly the first combustion grate 241. As a result, it is possible to stabilize the combustion state such as the combustion position, the amount of combustion, the temperature in the combustion chamber 2, etc., stabilize the amount of steam generated by the boiler, improve the efficiency of power generation, and reduce the amount of exhaust gas in the low air ratio combustion. It is possible to reduce the generation amount of NOx and CO, reduce the amount of chemicals related to exhaust gas treatment, and minimize the life cycle cost (LCC) of the incinerator 1.

  Further, the target waste height is changed based on the target waste layer thickness. As described above, since the target waste layer thickness is changed based on the target lower heating value and the target apparent specific gravity, the target waste height is substantially changed based on the target lower heating value and the target apparent specific gravity. .. Then, based on the dry grate dust height and the target dust height, the dust feed rate by the dust feed unit 4 is controlled. As a result, when the target dust layer thickness is changed, the calculated dust layer thickness can be approximated to the target dust layer thickness in a short time. In the incinerator 1, the bypass flow rate adjusting unit 332 (dry grate air temperature) may be controlled based on the dry grate dust height. Also in this case, it is possible to stabilize the combustion state in the combustion chamber 2.

  Various modifications can be made in the incinerator 1.

  In the refuse quality calculation unit 821, a weighted average value of the lower heating value and a representative value such as a median value acquired within a predetermined period may be obtained as the target lower heating value (similar in apparent specific gravity). Depending on the operation of the incinerator 1, the apparent specific gravity and the lower heating value at each time may be used as they are without obtaining the moving average value or the like.

  Depending on the design of the incinerator 1, the air preheater 321 is provided for each of the dry grate 23 and the combustion grate 24 so that the air supplied to the dry grate 23 is supplied to the combustion grate 24. It may be possible to adjust the temperature to a higher temperature.

  Depending on the quality of the waste processed in the incinerator 1, the waste height detector 74 may be provided on the side surface inside the combustion chamber 2.

  The configurations of the above-described embodiment and each modification may be appropriately combined unless they contradict each other.

1 Incinerator 2 Combustion Chamber 3 Air Supply Section 4 Waste Supply Section 6 EGR Gas Supply Section 8 Control System 9 Waste 21 Grate Section 23 Dry Grate 24 Combustion Grate 41 Hopper 52 Concentration Measuring Unit 53 Flowmeter 64 Front Wall EGR Gas nozzle 65 Rear wall side EGR gas nozzle 74 Waste height detection unit 75 Thermal image capturing unit 432 Weight scale 433 Volume measuring unit 821 Waste quality calculating unit

Claims (4)

A stoker incinerator,
It has a grate part that conveys waste along a predetermined conveyance route, and the grate part is adjacent to a dry grate on which the dust is dried and a downstream side of the dry grate in the conveyance route. Along with, a combustion chamber having a combustion grate in which the waste is burned,
At each position of the transport path, by supplying air to the dust, an air supply unit that burns the dust in the combustion chamber,
A hopper for storing the trash, a trash supply unit for supplying the trash in the hopper onto the dry grate,
While measuring the weight of dust thrown into the hopper, a laser rangefinder capable of scanning the inside of the hopper , or a volume measuring unit that is a stereo camera, to calculate the amount of change in the volume of dust in the hopper. By measuring the volume of the waste thrown into the hopper, an apparent specific gravity acquisition unit that acquires the apparent specific gravity of the waste,
Obtaining the lower heating value of waste by measuring the weight of the waste, the flow rate of exhaust gas discharged from the combustion chamber, and the concentration of water vapor and carbon dioxide contained in the exhaust gas. Department,
Based on the apparent specific gravity and the lower heating value, a flow rate of air supplied by the air supply unit, and a control unit that controls the transport speed of dust by the grate unit,
An EGR gas supply unit that supplies EGR gas containing exhaust gas discharged from the combustion chamber into the combustion chamber via two gas nozzles;
Equipped with
One of the two gas nozzles ejects the EGR gas toward the vicinity of dust on the dry grate, and the other gas nozzle is located at a position distant from the dry grate on the downstream side in the transport path. Ejecting the EGR gas from above,
The EGR gas supply unit can individually adjust the flow rate of the EGR gas ejected from the two gas nozzles,
Wherein the control unit, the apparent based on the specific gravity and the lower heating value, stoker incinerator, wherein said Rukoto to control the flow rate of the EGR gas from the two gas nozzle in the EGR gas supply unit. The stoker incinerator according to claim 1,
The air supply unit, the air supplied to the dry grate can be adjusted to a temperature higher than the temperature of the air supplied to the combustion grate,
The stoker incinerator, wherein the control unit controls the temperature of the air supplied to the dry grate by the air supply unit based on the apparent specific gravity and the lower heating value. The stoker incinerator according to claim 1 or 2 ,
A dust height detection for detecting the height of the dust on the dry grate by transmitting a radio wave to the surface of the dust on the dry grate and receiving a reflected wave of the radio wave from the surface. More parts,
The control unit changes the target value of the height of the dust on the dry grate based on the apparent specific gravity and the lower heating value, and the height of the dust acquired by the dust height detection unit. Based on the target value and the target value, controlling the supply speed of the waste by the waste supply unit ,
When the apparent specific gravity decreases, or when the lower heating value increases, the target value of the height of the dust is reduced, the apparent specific gravity increases, or when the lower heating value decreases. , stoker incinerator, wherein Rukoto the target value of the height of the dust is increased. The stoker incinerator according to any one of claims 1 to 3 ,
Further comprising a thermal image capturing unit for capturing a thermal image of dust on the grate unit,
The control unit, based on the position of the ignition point or burn-out point of the dust on the grate portion obtained from the thermal image, the flow rate of air supplied by the air supply unit, or of the dust by the grate unit A stoker-type incinerator characterized by controlling the transfer speed.

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