JP2017145979A - Stoker type incinerator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To more reliably keep a desired combustion state corresponding to variable quality of waste.SOLUTION: In an incinerator 1, a weight of waste charged into a hopper 41 and a volume of the waste in the hopper 41 are measured to acquire an apparent gravity of the waste. Further a low calorific power of the waste is acquired by measuring the weight of waste, a flow rate of an exhaust gas discharged from a combustion chamber 2, and a concentration of water vapor and a concentration of carbonic acid gas included in the exhaust gas. A supply flow rate of air to the waste on a fire grate portion 21 and a waste conveying speed by the fire grate portion 21 are controlled on the basis of the apparent gravity and the low calorific power. By implementing the control on the basis of both of the apparent gravity and the low calorific power, the desired combustion state corresponding to the variable quality of waste can be reliably kept.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a stoker-type incinerator.

  In the waste incinerator, combustion control is performed using the planned value of the waste quality expressed by the apparent specific gravity and the lower heating value. That is, each operation end is adjusted (controlled) in accordance with various target values set based on the waste quality plan value. Further, Patent Documents 1 and 2 propose a method for obtaining the specific gravity of the waste by detecting the waste weight and the waste volume, 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 amount of combustion exhaust gas, the amount of moisture in the exhaust gas, the amount of carbon dioxide gas, and the amount of incineration, and the lower heating value is used to automatically control the amount of air for drying, etc. A technique is disclosed.

Japanese Patent No. 3926173 Japanese Patent No. 3928709 Japanese Examined 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. Similarly, even if the apparent specific gravity is a small waste, the lower heating value is not always large. Therefore, the methods of Patent Documents 1 to 3 may not always maintain a preferable combustion state. Therefore, there is a need for a new technique that more reliably maintains a favorable combustion state in accordance with the changing quality of garbage.

  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 the changing quality of dust.

  The invention according to claim 1 is a stoker-type incinerator having a grate part that conveys garbage along a predetermined conveyance path, and the grate part is a dry fire in which the garbage is dried. A combustion chamber having a lattice, a combustion grate adjacent to the downstream side of the dry grate in the conveyance path and where the dust is burned, and air at each position of the conveyance path An air supply unit that burns the garbage in the combustion chamber by supplying, a hopper that stores the waste, and a garbage supply unit that supplies the waste in the hopper onto the dry grate, An apparent specific gravity acquisition unit that acquires the apparent specific gravity of the waste by measuring the weight of the waste introduced into the hopper and the volume of the waste in the hopper, the weight of the waste, and the exhaust gas discharged from the combustion chamber Flow rate In addition, by measuring the concentration of water vapor and the concentration of carbon dioxide contained in the exhaust gas, based on the lower calorific value acquisition unit for acquiring the lower calorific value of waste, the apparent specific gravity and the lower calorific value, A control unit that controls an air supply flow rate by the air supply unit and a dust conveyance speed by the grate unit.

  Invention of Claim 2 is a stoker type incinerator of Claim 1, Comprising: The temperature which the said air supply part supplies to the said dry grate from the temperature of the air supplied to the said combustion grate 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.

  Invention of Claim 3 is a stoker type incinerator of Claim 1 or 2, Comprising: EGR gas containing the waste gas discharged | emitted from the said combustion chamber is supplied in the said combustion chamber via two gas nozzles An EGR gas supply unit, wherein one gas nozzle 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 disposed in the transport path on the dry grate. The EGR gas is ejected from above the position away from the downstream side, the EGR gas supply unit can individually adjust the flow rate of the EGR gas ejected from the two gas nozzles, the control unit, Based on the apparent specific gravity and the lower heating value, the flow rate of the EGR gas from the two gas nozzles in the EGR gas supply unit is controlled.

  Invention of Claim 4 is a stoker type incinerator in any one of Claim 1 thru | or 3, Comprising: A radio wave is transmitted toward the surface of the garbage on the said dry grate, The said surface of the said radio wave Further comprising a dust height detection unit for detecting the height of the dust on the dry grate by receiving a reflected wave from the control unit, the control unit based on the apparent specific gravity and the lower heating value, The target value of the height of the dust on the dry grate is changed, and the dust supply rate by the dust supply unit based on the dust height and the target value acquired by the dust height detection unit To control.

  Invention of Claim 5 is a stoker type incinerator in any one of Claim 1 thru | or 4, Comprising: The thermal image imaging part which images the thermal image of the garbage on the said grate part is further provided, Based on the position of the ignition point or the burnout point of the garbage on the grate unit, which is obtained from the thermal image, the control unit supplies the air supply flow rate by the air supply unit or the conveyance of the garbage 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 calorific value, a preferable combustion state can be more reliably maintained in accordance with the varying quality of dust.

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 garbage 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 function structure of a correction | amendment control unit. It is a figure which shows the other function structure of a correction | amendment control unit. It is a figure which shows the other function structure of a correction | amendment 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 shown in FIG. 1 is a stoker-type incinerator that burns waste as a waste while conveying it with a plurality of grate (stalkers).

  The incinerator 1 includes a combustion chamber 2, an air supply unit 3, a dust supply unit 4, a discharge 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 combustion product gas mainly composed of carbon and hydrogen generated from the waste are performed. Exhaust gas (combustion gas) discharged from the combustion chamber 2 is subjected to predetermined exhaust gas treatment in the discharge path 5 and guided to the atmosphere.

  The garbage supply unit 4 includes a hopper 41 and a dust supply device 42. The hopper 41 stores garbage. Garbage is thrown into the hopper 41 from the garbage pit by the crane 431. The crane 431 is provided with a weight scale 432, and the weight of garbage thrown into the hopper 41 is acquired. Further, the volume of dust in the hopper 41 is measured by a volume measuring unit 433 that is a scanable laser distance meter or a stereo camera. Actually, every time garbage is thrown into the hopper 41 by the crane 431, the amount of change in the volume of the garbage in the hopper 41 is calculated, and the volume of the thrown garbage is acquired. In the control system 8, the sum of the weight and the sum of the volume of the waste introduced into the hopper 41 per unit time is obtained. In the following description, the garbage thrown into the hopper 41 within each unit time is called “garbage group”, and the weight and volume of the garbage group are called “garbage group weight” and “garbage group volume”.

  The dust supply device 42 supplies dust in the hopper 41 onto a later-described grate portion 21 in the combustion chamber 2 by an extrusion operation by a drive mechanism 421 such as a pusher or a screw. By controlling the drive mechanism 421, the supply speed of dust from the dust supply device 42 onto the grate portion 21 (for example, the number of extrusion operations per predetermined time, hereinafter referred to as “dust supply device 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 grates arranged continuously between the two. The garbage on the grate portion 21 moves toward the discharge portion 22 by the reciprocating motion of the movable grate arranged every other one in the plurality of grate. As described above, the plurality of grate of the grate unit 21 conveys garbage along the conveyance path from the dust feeder 42 toward the discharge unit 22. As will be described later, air is supplied to the dust at each position of the transport path by the air supply unit 3, and the dust burns in the combustion chamber 2. Garbage after combustion (mainly ash) is discharged out of the combustion chamber 2 by the discharge unit 22. In addition, various things can be employ | adopted about the shape of the some grate in the grate part 21, arrangement | sequence, operation | movement, etc. FIG.

  The conveyance path on the grate 21 is divided into three parts in the direction of garbage movement. Dust is supplied to the portion 23 on the side of the dust supply device 42 in the transport path by the dust supply device 42, and the dust is mainly dried in the portion 23. In the central portion 24 in the transport path, dust is mainly burned, and in the portion 25 on the discharge unit 22 side, waste is mainly burned. In the following description, the three portions 23, 24, and 25 in the conveyance path are referred to as a dry grate 23, a combustion grate 24, and a post-combustion grate 25, respectively. In the conveying 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. For each of the dry grate 23, the first combustion grate 241, the second combustion grate 242, and the post-combustion grate 25, a drive mechanism 26 that drives the movable grate is provided. In the dry grate 23, the first combustion grate 241, the second combustion grate 242, and the post-combustion grate 25, the conveyance speed of garbage can be individually adjusted. In the following description, the dust conveyance speeds in the dry grate 23, the combustion grate 24, and the post-combustion grate 25 are 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 is indicated by a broken line). The air preheater 311 heats combustion air supplied from 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, which are the dry grate 23, the first combustion grate 241, the second combustion grate 242, the first The first post-combustion grate 251 and the second post-combustion grate 252 are respectively connected. The heated air supply pipe 312 causes the heated air from the air preheater 311 to become dry grate 23, first combustion grate 241, second combustion grate 242, first post-combustion grate 251 and second post-combustion grate. 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 at a temperature lower than that of the heated air is mixed with the heated air using the position 316 where the auxiliary air supply pipe 313 is connected in the heated air supply pipe 312 as a mixing position. A thermometer 331 is provided between the mixing position 316 and the branch pipe 315 in the heated air supply pipe 312. The flow rate of heated air discharged from the air preheater 311 (that is, the flow rate of air supplied to the air preheater 311) and the auxiliary air supply pipe so that the output value of the thermometer 331 becomes 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 a position (hereinafter simply referred to as “connection position”) between the air preheater 311 and the mixing position 316 in the heated air supply pipe 312. 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 flows, and the heated air is supplied to the bypass pipe 314. The bypass pipe 314 is provided with a bypass flow rate adjustment unit 332 including a damper. In the air supply unit 3, the air supplied to the dry grate 23 can be adjusted to a temperature higher than the temperature of the air supplied to the combustion grate 24 and the post-combustion grate 25 by the bypass flow rate adjustment unit 332. Actually, 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.

  Each branch pipe 315 is provided with a damper 334 and a flow meter 335. 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 gage. The flow rate of the air supplied to each of the grid 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 unit 31 to the grate unit 21 is referred to as “primary air”. Further, the flow rates of the primary air supplied to the dry grate 23, the combustion grate 24 and the post-combustion grate 25 are “dry grate air flow rate”, “combustion grate air flow rate” and “post-combustion grate air flow rate”, respectively. These total flow rates are called “primary air flow rates”. The combustion grate air flow rate may be set individually in the first combustion grate 241 and the second combustion grate 242, and the post combustion grate air flow rate is also 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 illustrating a 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 the front wall side secondary air nozzle 326 and the rear wall side secondary air nozzle 327, respectively. . 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 a pipe between the fan 324 and the air preheater 321. Unheated air is mixed with the heated air flowing through the heated air supply pipe 322 by the auxiliary air supply pipe 323. In the heated air supply pipe 322, a thermometer 341 is provided between a position where the auxiliary air supply pipe 323 is connected and the branch pipe 325. The flow rate of heated air discharged from the air preheater 321 (that is, the flow rate of air supplied to the air preheater 321) and the auxiliary air supply pipe so that the output value of the thermometer 341 becomes a predetermined target temperature. The flow rate of unheated air flowing through H.323 is adjusted.

  Each branch pipe 325 is provided with a damper 342 and a flow meter 343. The control system 8 controls the damper 342 based on the output value of the flow meter 343, so that 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 the air ejected from 327 can be individually adjusted. 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 determined. 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, hereinafter referred to as “EGR gas”) is passed through the fan 62. Supplied. The EGR gas is, for example, a mixture of exhaust gas and air that has passed through a bag filter (not shown) provided in the discharge path 5. The EGR gas may be a gas containing only the exhaust gas. That is, 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 connected to two gas nozzles, that is, a front wall side EGR gas nozzle 64 and a rear wall side EGR gas nozzle 65, respectively. Is done. Each branch pipe 63 is provided with a damper 66 and a flow meter 67. 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, combustion from the front wall side EGR gas nozzle 64 and the rear wall side EGR gas nozzle 65 is performed. 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 “front wall side EGR gas flow rate” and “rear wall side EGR gas flow rate”. The flow rate is referred to as “EGR gas flow rate”.

  In the combustion chamber 2 shown in FIG. 1, a front wall portion 201 that covers the upper portion of the dry grate 23 and a rear wall portion 202 that covers the upper portion of the rear 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, secondary air is supplied (spouted) from the front wall side secondary air nozzle 326 and the rear wall side secondary air nozzle 327 to the gas traveling toward the discharge path 5. Thereby, the unburned gas generated in the combustion chamber 2 burns. Further, EGR gas is ejected from the front wall side EGR gas nozzle 64 toward the vicinity of the dust on the drying grate 23, and the rear wall side EGR gas nozzle 65 is located above the position away from the drying grate 23 downstream in the conveying path. Thus, EGR gas is ejected into the combustion chamber 2. By supplying EGR gas into the combustion chamber 2, the combustion temperature is lowered. Thereby, generation | occurrence | production of thermal NOx (nitrogen oxide) is suppressed and NOx density | concentration reduction etc. are implement | achieved.

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

  In 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. One thermometer 721 is located in the combustion chamber 2 in the vicinity of the connection with the discharge path 5, that is, in the vicinity of the outlet of the combustion chamber 2. Hereinafter, the temperature acquired by the thermometer 721 is referred to as “combustion chamber outlet temperature”. Another thermometer 722 is located above the rear combustion grate 25 in the combustion chamber 2. Hereinafter, the temperature acquired by the thermometer 722 is referred to as “post-combustion grate upper temperature”. Another thermometer may be provided in the combustion chamber 2.

  The garbage 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 acquired 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, based on the differential pressure, the amount of primary air supplied to the combustion grate 24, and the like, the thickness of the dust layer on the combustion grate 24 (the estimated value of the thickness, Hereinafter, “calculated garbage layer thickness”) is acquired.

  The thermal image capturing unit 75 is attached to, for example, the rear wall unit 202 and captures a thermal image of dust on the grate unit 21. The thermal image capturing unit 75 is an infrared camera, and has a 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 unit 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 the bright flame is removed by a predetermined process, and the combustion state (specifically, the surface temperature) of the dust in the combustion chamber 2 can be accurately grasped. As will be described later, the IR thermal image is used to detect the combustion 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 illustrating a configuration of the dust height detection unit 74. In FIG. 4, the dust height detector 74 is shown in an enlarged manner. The dust height detection unit 74 is provided on the front wall 201 and includes a measurement unit 741 and an annular nozzle 742. The measuring unit 741 is disposed above the garbage 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 measurement plane 743. The transmitter and receiver may share an antenna. In the measurement unit 741, a radio wave in the microwave band is transmitted from the measurement surface 743 toward the surface of the dust 9 on the dry grate 23, and a reflected wave from the surface of the dust 9 is received by the measurement surface 743. . Thereby, the height of the dust 9 on the dry grate 23 (hereinafter referred to as “dry grate dust height”) is detected. In particular, the measurement unit 741 can detect that the dust 9 is stably supplied onto the dry grate 23 by detecting the level of the upper part of the dust 9 on the dry grate 23 obliquely. Is preferred. The garbage height detection unit 74 may use millimeter wave radio waves or the like.

  The annular nozzle 742 is an annular shape that surrounds the periphery of the measurement unit 741 and has an annular ejection port. The annular spout constantly ejects purge gas. The purge gas ejected from each part of the annular ejection port collides with the purge gas ejected from another part of the annular ejection port at the focal point in the vicinity of the measurement surface 743. Thereby, the measurement surface 743 is disposed in a space surrounded by the flow of the purge gas. The purge gas is preferably EGR gas containing exhaust gas. In the dust height detection unit 74, the measurement surface 743 is prevented from being contaminated by the purge gas, and the dry grate dust height is detected stably and accurately. 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 in the vicinity of the combustion chamber 2 in the discharge 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 measurement unit 52 and the flow meter 53 are provided downstream 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 gas (hereinafter referred to as “exhaust gas moisture concentration” and “exhaust gas CO ₂ concentration”) contained in the exhaust gas. The flow meter 53 measures the flow rate of the 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, a heat loss 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 each control unit of the basic control unit 81 and the types of values (operation parameters) commanded (output) by the control unit. 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 changed as appropriate. In the case where operation parameters are duplicated in a plurality of control units included in the basic control unit 81, the weights determined for the plurality of control units (which may be different for each operation parameter) are taken into consideration. Thus, the actual command value of the operation parameter is determined.

  In the steam amount control unit 811, an operation for approximating the boiler generated steam amount to a target steam amount described later is performed. For example, when the boiler generated steam amount is larger than the target steam amount, the command value of the waste feed reference speed is reduced from the current value. Here, the command value for the waste feed reference speed is the reference value for calculating the command value for the dust feeder speed, the command value for the dry grate speed, the command value for the combustion grate speed, and the command value for the post-combustion grate speed. It will be. When the command value of the garbage 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 are reduced. When the boiler generated steam volume is smaller than the target steam volume and the command value of the garbage feed reference speed is increased, the command value of the dust feeder speed, the command value of the drying grate speed, the command value of the combustion grate speed, and The command value for the post-combustion grate speed increases.

  Further, when the boiler generated steam amount is larger than the target steam amount, 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 primary air flow rate command value serves as a reference in the calculation of the dry grate air flow rate command value, the combustion grate air flow rate command value, and the post-combustion grate air flow rate command value. As the primary air flow rate command value increases or decreases, the dry grate air flow rate command value, the combustion grate air flow rate command value, and the post-combustion grate air flow rate command value also increase or decrease in the same manner. The command value of the secondary air flow rate is a command value of the total flow rate of 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 determined as a reference air amount, and the change in the command value of the primary air flow rate and the command value of the secondary air flow rate is a change in the ratio of each flow rate to the reference air amount ( The same applies below). When the boiler generated steam amount is smaller than the target steam amount, the command value for the primary air flow rate is increased from the current value, and the command value for the secondary air flow rate is decreased 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 determining the volume of garbage 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 incineration amount constant control, which will be described later, and details will be described later.

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

  In the thermal reduction control unit 816, when the post-combustion grate upper temperature is higher than the preset upper set temperature, the post-combustion grate air flow command value is increased from the current value, and the post-combustion grate speed is increased. Command value is reduced from the current value. When the post-combustion grate upper temperature is lower than the set upper temperature, the post-combustion grate air flow command value 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 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 Each is reduced from the current value. When the post-combustion grate upper temperature is lower than the set upper temperature, the dry grate speed command value, the combustion grate speed command value, and the post-combustion grate speed command value each increase from the current value. Is done.

  In the waste layer thickness control unit 818, when the calculated waste layer thickness is larger than the target waste layer thickness, 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 set. Each is reduced from the current value. The target waste layer thickness is determined according to the target incineration amount described later. When the calculated waste layer thickness is smaller than the target waste layer thickness, each of the command value for the feeding device speed, the command value for the dry grate speed, and the command value for the combustion grate speed is increased from the current value. . In this way, based on the calculated garbage layer thickness, the conveyance speed of the garbage by the grate part 21 is controlled.

  FIG. 6 is a diagram illustrating 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 garbage quality calculation unit 821 obtains the apparent specific gravity (specific gravity with respect to water here) of each garbage group based on the garbage group weight and the garbage group volume. As will be described later, the apparent specific gravity of the garbage group is used for calculating various reference values. In the incinerator 1, an apparent specific gravity acquisition unit that acquires the apparent specific gravity of the waste is realized by the weight scale 432 that acquires the waste group weight, the volume measurement unit 433 that acquires the waste group volume, the waste quality calculation unit 821, and the like. The

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

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

Further, when 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 garbage is expressed by Equation 2.

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

When the ratio of carbon in the elemental composition of combustible waste is _RC and the weight percent concentration of combustible waste is B, the amount of carbon dioxide gas V (CO ₂ ) per 1 kg of waste is expressed by Equation 3. The

(Equation 3)
V (CO ₂ ) = (R _C /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 combustibles in the garbage is _RH , the amount of water vapor V ′ (H ₂ O) resulting from hydrogen in the combustibles in the garbage is expressed by Equation 4.

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

Further, when the weight percent concentration of water in the waste is W, the water vapor amount V ″ (H ₂ O) caused by the water is expressed by the following equation (5).

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

Therefore, the amount of water vapor V (H ₂ O) per 1 kg of garbage is expressed by Equation 6.

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

  The weight percent concentration B of the combustible portion of the garbage is expressed by Equation 7 from Equation 3.

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

  Further, from the equations (6) and (7), the weight percent concentration W of water in the waste is expressed by the following equation (8).

(Equation 8)
W = 80.4 × V (H ₂ O) −478 × (R _H / R _C ) × V (CO ₂ )

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

(Equation 9)
Hu = 50 × B-6 × W

Therefore, the flow rate G of exhaust gas per unit time at a certain time, the exhaust gas moisture concentration C (H ₂ O), and the exhaust gas CO ₂ concentration C (CO ₂ ) are supplied onto the grate unit 21 per unit time. By using the rubbish weight Q (the actual incineration amount described above), the lower heating value Hu is calculated (estimated) from Equation 1, Equation 2, Equation 7, Equation 8, and Equation 9. In addition, the value acquired by the prior analysis etc. is used for the ratio _RC of carbon and the ratio _RH of hydrogen in the elemental composition of the combustible part in refuse. In the incinerator 1, a weight meter 432 that acquires the weight of waste, a flow meter 53 that acquires the flow rate of exhaust gas, a concentration measurement unit 52 that acquires the concentration of water vapor and carbon dioxide contained in the exhaust gas, and the waste quality The calculation unit 821 and the like realize a low heat generation amount acquisition unit that acquires a low heat generation amount of garbage.

  The waste quality calculation unit 821 uses the average value of the lower heating value acquired within the most recent predetermined period at each time and the average value of the apparent specific gravity of the garbage group corresponding to the lower heating value at that time. Power lower heat value and apparent specific gravity (hereinafter referred to as “target lower heat value” and “target apparent specific gravity”, respectively). The target apparent specific gravity may be an average value of apparent specific gravity acquired within the most recent predetermined period. Moreover, it is preferable that the acquired specific gravity and the lower heating value match the dust groups corresponding to the lower heating value by considering a time difference according to the speed of the feeding device. In this way, by obtaining the moving average value of low calorific value and apparent specific gravity, it is possible to grasp medium- to long-term fluctuations in garbage quality (seasonal, collection date, fluctuation due to weather, etc.), and perform correction control described later. It becomes possible to carry out with high accuracy. In addition, even if the lower calorific value or apparent specific gravity becomes an abnormal value, it suppresses rapid fluctuations in the target lower calorific value and target apparent specific gravity (and various reference values calculated using these values). Can do. From the viewpoint of grasping medium- to long-term fluctuations in the quality of garbage, the target low calorific value and target apparent specific gravity at each time are processed slightly before the garbage actually processed at that time. It is not a problem that the value is based on garbage.

  In the waste quality correction control unit 822, for example, in the case of performing control to make the boiler generated steam amount constant at a set steam amount set in advance by the user (constant steam amount control), the set steam amount, the target lower heating value And the reference value of the waste feed reference speed to be used in the current control, the reference value of the primary air flow rate, and the reference value of the secondary air flow rate are calculated and updated using the target apparent specific gravity. In the steam amount constant control, the set steam amount becomes the target steam amount.

  In an example of calculating various reference values, the total heat quantity is obtained by multiplying the set steam quantity by a predetermined conversion coefficient, and the target incineration quantity is obtained by dividing the total heat quantity by the target lower heating value. Further, the reference value of the waste feed reference speed is obtained by dividing the target incineration amount by the target apparent specific gravity and further by a predetermined conversion coefficient. When the reference value of the new (updated) waste feed reference speed is increased or decreased from the previous reference value (before update), the command value of the waste feed reference speed is similarly increased or decreased.

  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, by multiplying the reference air amount by two values obtained by inputting the target lower heating value into the other two functions, the reference value of the primary air flow rate and the reference value of the secondary air flow rate are obtained. 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 updated reference value of the primary air flow rate increases or decreases from the reference value before the update, the command value of the primary air flow rate also increases or decreases in the same manner (the same applies to the secondary air flow rate). The reference air amount may be 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. Various reference values and the like may be obtained by various calculations as long as the target low calorific value and the target specific gravity are used.

  When the current target low calorific value is greater than the previous target low calorific value, or the current target apparent specific gravity is smaller than the previous target apparent specific gravity, the dust feeding device is updated by updating the reference value of the waste feed reference speed. The speed command value, the dry grate speed command value, the combustion grate speed command value, and the post-combustion grate speed command value are lower than the current value. Further, by updating the reference value for the primary air flow rate and the reference value for the secondary air flow rate, the command value for the primary air flow rate becomes lower and the command value for the secondary air flow rate becomes higher. When the target lower heating value or the target apparent specific gravity varies in the opposite direction, the command value of each operation parameter varies in the opposite direction (the same applies hereinafter).

  The garbage quality correction control unit 822 further includes 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, and 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 low calorific value, or when the current target apparent specific gravity is smaller than the previous target apparent specific gravity, the command value of the dry grate air flow rate, the front wall side EGR gas 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 a change of the ratio of each flow rate to the command value of the primary air flow rate (change of the command value of the post-combustion grate air flow rate The same in). The change in 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 are also changes in 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 low calorific value, and the current target apparent specific gravity is larger (smaller) than the previous target apparent specific gravity, the target low calorific value and target apparent A command value for each operation parameter is determined in consideration of a weight determined for each specific gravity (which may be different for each operation parameter).

  The waste quality correction control unit 822 may perform control (incineration amount constant control) that makes the actual incineration amount constant at a preset incineration amount set in advance by the user. In this case, the incineration amount control unit 813 in 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. If the integrated value of the actual incineration amount is smaller than the integrated value of the set incineration amount, the actual incineration amount will increase, and if 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 waste feed reference speed is reduced from the current value, and by increasing the target steam amount, the command value of the waste feed reference speed is increased from the current value. In addition, the reference value of the waste 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 varies 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 command value variation of each operation parameter is the same as in FIG. is there.

  As described above, in the incinerator 1, the reference value of the waste 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. And based on these reference values, the conveyance speed of the garbage by the grate part 21, and the supply flow rate of the air by the air supply part 3 with respect to the garbage on the grate part 21 are controlled. In this way, by performing control based on both the target apparent specific gravity and the target lower calorific value, it is possible to more reliably maintain a preferable combustion state in accordance with the quality of dust that varies in the medium and long term. As a result, stable low air ratio combustion can be realized, and the generation of NOx, CO (carbon monoxide) and dioxins in the exhaust gas can be reduced. In addition, high efficiency of power generation, small amount of chemicals related to exhaust gas treatment, life extension of boiler 711 by suppressing abnormal temperature rise in combustion chamber 2, and minimization of life cycle cost (LCC) of incinerator 1 are realized. can do.

  Further, the temperature of the air supplied to the dry grate 23 by the air supply unit 3 (dry grate air temperature) is controlled based on the target apparent specific gravity and the target lower heating value. Thereby, the dust on the dry grate 23 can be appropriately dried in accordance with the changing quality of the dust, and a preferable combustion state can be more reliably 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 is obtained. The air having a temperature lower than that of the heated air is mixed with the heated air. Further, a position between the air preheater 311 and the mixing position 316 in the heated air supply pipe 312 is connected to the dry grate 23 by a bypass pipe 314. Then, by controlling the bypass flow rate adjustment unit 332 based on the target apparent specific gravity and the target lower heating value, the dry grate air temperature is adjusted. With such a structure, in the air supply unit 3, dust is appropriately dried in the drying grate 23 and the number of the air preheaters 321 is reduced (compared to the case where the air preheaters 321 are provided in the branch pipes 315). Thus, the manufacturing cost of the incinerator 1 can be reduced.

  By the way, if the dry grate air flow rate is excessively increased, the dust in the hopper 41 may be ignited (backfire), and 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 rates of the EGR gas from the front wall side EGR gas nozzle 64 and the rear wall side EGR gas nozzle 65 are also controlled based on the target apparent specific gravity and the target lower heating value. Further, in the EGR gas, the amount of high-temperature combustion gas drawn in is adjusted to increase or decrease the radiant heat to the dust on the dry grate 23, thereby controlling the degree of drying of the dust. Thereby, the garbage on the dry grate 23 can be appropriately dried while suppressing the occurrence of backfire. In addition, an excessive increase in the amount of air supplied into the combustion chamber 2 is also prevented. In the EGR gas supply unit 6, EGR gas may be supplied into the combustion chamber 2 through 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 fuel cut point position calculation unit 825, and a fuel cut point control unit 826. In the ignition point position calculation unit 823, the position of the garbage ignition point is obtained based on the IR thermal image. In the ignition point control unit 824, feedback control based on the position of the ignition point is performed. For example, when the ignition point position is upstream of the preset ignition point position, that is, on the side of the refueling device 42, the command value of the rear wall EGR gas flow rate is increased, and the dry grate air temperature command Value, front wall EGR gas flow rate command value, and 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 EGR gas flow rate on the front wall side, and the command value of the dry grate air flow rate, the drying of garbage in the dry grate 23 is suppressed, and the position of the ignition point is downstream. Move to the side. Further, when the ignition point position is on the downstream side of the set ignition point position, that is, on the discharge part 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, the front wall side The command value for the EGR gas flow rate and the command value for the dry grate air flow rate are increased. Thereby, the drying of the garbage in the drying grate 23 is promoted, and the position of the ignition point moves to the upstream side.

  In addition, in the fuel cut point position calculation unit 825, the position of the fuel cut point of garbage is obtained based on the IR thermal image. The fuel cut point control unit 826 performs feedback control based on the position of the fuel cut point. For example, when the fuel cut-off point position is upstream of the preset fuel cut-off point position, a command value for the feed device speed, a command value for the dry grate speed, and a command value for the combustion grate speed Then, the command value of the post-combustion grate speed is increased (that is, the command value of the garbage feed reference speed is increased), and the command value of the post-combustion grate air flow rate is decreased. 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 fuel cut point moves downstream. In addition, when the fuel cut-off point position is downstream of the set fuel cut-off point position, a command value for the dust feeder speed, a command value for the dry grate speed, a command value for the combustion grate speed, and The command value for the combustion grate velocity is reduced and the command value for the post-combustion grate air flow rate is increased. By increasing the command value of the post-combustion grate air flow rate, the combustion of garbage in the post-combustion grate 25 is promoted, and the position of the burnout point moves upstream. 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 fuel cut point.

  Here, the incinerator of the comparative example which abbreviate | omitted the correction | amendment control unit 82 of FIG. 7 is assumed. As described above, in the basic control unit 81 of FIG. 5, the combustion position is controlled by the combustion position control unit 817 based on the upper temperature of the rear 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 the dust varies, a delay occurs in the combustion control, and in particular, the position of the ignition point of the dust becomes unstable. As a result, in the incinerator of the comparative example, fluctuations in the amount of steam generated by the boiler, an increase in unburned material due to the combustion position moving downstream, and the like may occur.

  On the other hand, in the incinerator 1 including the correction control unit 82 of FIG. 7, the position of the garbage ignition point on the grate portion 21 is quickly acquired from the IR thermal image, and the air supply is performed based on the position of the garbage ignition point. The bypass flow rate adjusting unit 332 of the unit 3 is controlled (that is, the dry grate air temperature is controlled). Thereby, the control which maintains the position of the ignition point of garbage constant can be performed stably and accurately. Further, the position of the ignition point of the garbage is controlled by controlling the front wall side 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 garbage ignition point on the grate portion 21. Control that keeps constant can be performed with higher accuracy. Furthermore, based on the position of the burnout point of the garbage on the grate part 21 acquired from the IR thermal image, the speed of the feeder, the drying 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 burnout point of the waste.

  In this way, by keeping the position of the ignition point and burnout point of the garbage constant, stabilization of the amount of steam generated in the boiler, reduction of unburned substances, and reduction in the amount of NOx and CO generated in the exhaust gas in low air ratio combustion In addition, stabilization of the temperature in the combustion chamber 2 can be realized. In practice, the operation of the ignition point control unit 824 and the fuel cut point control unit 826 can 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 garbage ignition point and the burnout point, or the moving acceleration and direction. Moreover, the conveyance speed of the garbage by the grate part 21 may be controlled based on the position of the ignition point of garbage. As described above, in the incinerator 1, based on the position of the ignition point or burnout point of the dust obtained from the IR thermal image, the air supply flow rate by the air supply unit 3 (in the above example, the dry grate air flow rate or The post-combustion grate air flow rate) or the dust conveyance speed by the grate portion 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 dust quality correction control unit 822 in FIG. 6 based on the target lower heating value and the target apparent specific gravity. The updated target dust layer thickness is input to the target dust height correcting unit 827, and when it becomes larger than the value before the update, the height of the dust on the dry grate 23 (that is, the dry grate dust height). The target garbage height, which is the target value of, is increased from the current value. When the updated target dust layer thickness is smaller than the value before the update, the target dust height is reduced from the current value.

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

  In the incinerator 1, in the combustion chamber 2, the dust height detector 74 is provided above the dust on the dry grate 23 (see FIG. 4) without being affected by clinker adhesion, The height of the dust on the dry grate 23 can be detected accurately and stably. In the dust height detection unit 74, a purge gas is ejected from the periphery of the measurement surface 743 that transmits radio waves and receives reflected waves by an annular nozzle 742. As a result, the measurement surface 743 can be prevented from being contaminated by dust, and the height of the dust on the dry grate 23 can be detected with higher accuracy. By using the EGR gas as the purge gas, it is possible to prevent the air from being excessively supplied into the combustion chamber 2 and to realize the low air ratio combustion more reliably. Depending on the design of the incinerator 1, the purge gas may be nitrogen gas or may contain air.

  Further, based on the dry grate garbage height, the garbage supply speed (dust supply apparatus speed) by the garbage supply unit 4 is controlled. Therefore, even if an excess or deficiency in the amount of dust supplied by the dust supply unit 4 temporarily occurs due to dust quality or fluctuations in the pressure density of the dust in the hopper 41, the speed of the dust feeder (and the drying grate) (Speed) can be changed quickly to suppress rapid fluctuations 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 combustion amount, the temperature in the combustion chamber 2, etc., stabilize the amount of steam generated in the boiler, increase the efficiency of power generation, and reduce the ratio of exhaust gas in the combustion at low air ratio combustion. Reduction of the amount of NOx and CO generated, reduction of the amount of chemicals related to exhaust gas treatment, minimization of the life cycle cost (LCC) of the incinerator 1 can be realized.

  Further, the target garbage height is changed based on the target garbage layer thickness. As described above, since the target waste layer thickness is changed based on the target low heat generation amount and the target apparent specific gravity, the target waste height is substantially changed based on the target low heat generation amount and the target apparent specific gravity. . Based on the dry grate garbage height and the target garbage height, the garbage supply speed by the garbage supply unit 4 is controlled. As a result, when the target waste layer thickness is changed, the calculated waste layer thickness can be approximated to the target waste layer thickness in a short time. In the incinerator 1, the bypass flow rate adjustment unit 332 (dry grate air temperature) may be controlled based on the dry grate dust height. Also in this case, the combustion state in the combustion chamber 2 can be stabilized.

  Various modifications are possible in the incinerator 1.

  The garbage quality calculation unit 821 may obtain a weighted average value of the lower heating value acquired within a predetermined period, a representative value such as a median value, and the like as the target lower heating value (the same applies to the apparent specific gravity). Further, 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, an 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 to a higher temperature.

  Depending on the quality of the waste to be processed in the incinerator 1, the dust height detection unit 74 may be provided on the side surface in the combustion chamber 2.

  The configurations in the above-described embodiments and modifications may be combined as appropriate as long as they do not contradict each other.

DESCRIPTION OF SYMBOLS 1 Incinerator 2 Combustion chamber 3 Air supply part 4 Garbage supply part 6 EGR gas supply part 8 Control system 9 Garbage 21 Grate part 23 Dry grate 24 Combustion grate 41 Hopper 52 Concentration measurement unit 53 Flowmeter 64 Front wall side EGR Gas nozzle 65 Rear wall side EGR gas nozzle 74 Garbage height detection unit 75 Thermal imaging unit 432 Weigh scale 433 Volume measurement unit 821 Garbage quality calculation unit

Claims (5)

A stoker-type incinerator,
A grate part that conveys garbage along a predetermined conveyance path, and the grate part is adjacent to a dry grate in which the garbage is dried and downstream of the dry grate in the conveyance path And a combustion chamber having a combustion grate in which the waste is burned,
An air supply unit that burns the waste in the combustion chamber by supplying air to the waste at each position of the transport path;
A hopper for storing trash, and a trash supply unit for supplying the trash in the hopper onto the dry grate,
An apparent specific gravity acquisition unit that acquires the apparent specific gravity of the waste by measuring the weight of the waste put into the hopper and the volume of the waste in the hopper;
Acquire low calorific value 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 to obtain the low calorific value of the waste And
Based on the apparent specific gravity and the lower heating value, a control unit for controlling the air supply flow rate by the air supply unit, and the dust conveyance speed by the grate unit,
A stoker-type incinerator characterized by comprising: A stoker-type incinerator according to claim 1,
The air supply unit can adjust the air supplied to the dry grate to a temperature higher than the temperature of the air supplied to the combustion grate,
The stoker-type incinerator, wherein the control unit controls the temperature of air supplied to the dry grate by the air supply unit based on the apparent specific gravity and the lower heating value. A stoker-type incinerator according to claim 1 or 2,
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;
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 located at a position away from the dry grate downstream in the transport path. The EGR gas is ejected from above,
The EGR gas supply unit can individually adjust the flow rate of the EGR gas ejected from the two gas nozzles,
The stoker type incinerator, wherein the control unit controls the flow rate of the EGR gas from the two gas nozzles in the EGR gas supply unit based on the apparent specific gravity and the lower heating value. A stoker-type incinerator according to any one of claims 1 to 3,
Waste height detection for detecting the height of the dust on the dry grate by transmitting a radio wave toward the surface of the dust on the dry grate and receiving a reflected wave from the surface of the radio wave Further comprising
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 And a stoker-type incinerator that controls a waste supply speed by the waste supply unit based on the target value. A stoker-type incinerator according to any one of claims 1 to 4,
A thermal image capturing unit that captures a thermal image of garbage on the grate unit;
Based on the position of the ignition point or the burnout point of the dust on the grate portion obtained from the thermal image, the control unit supplies the air supply flow rate by the air supply unit, A stoker-type incinerator characterized by controlling the conveyance speed.

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