JP6146671B2 - Waste incinerator and waste incineration method - Google Patents

Description

  The present invention relates to a grate-type waste incinerator and a waste incineration method for incinerating waste such as municipal waste.

  Grate-type waste incinerators are widely used as incinerators for incinerating waste such as municipal waste. The outline of the configuration of the representative one will be described below.

  The grate-type waste incinerator has a three-stage grate (dry grate, combustion grate, and post-combustion grate) that is arranged in the direction of waste movement at the bottom of the combustion chamber that burns the waste. The secondary combustion chamber is connected to the outlet of the combustion chamber located above the post-combustion grate. The combustion chamber is provided with a waste inlet located above the dry grate. An ash drop port is provided at the downstream side of the post-combustion grate waste in the moving direction. Usually, the secondary combustion chamber is also a part of a waste heat boiler for waste heat recovery, and is in the vicinity of the inlet. Further, a combustion primary air blowing mechanism for blowing combustion primary air from below the grate of each of the dry grate, the combustion grate, and the post-combustion grate is provided.

  In such a grate-type waste incinerator, waste thrown into the combustion chamber from the waste inlet is deposited on the dry grate and dried by air from the bottom of the dry grate and radiant heat in the furnace. At the same time, the temperature is raised and ignition occurs. That is, immediately above the dry grate, a dry region is formed in the upstream space in the waste movement direction, and combustion occurs from the downstream space directly above the dry grate to the upstream space directly above the combustion grate. A starting region is formed. The waste that ignites in the combustion start area and starts combustion is sent from the dry grate onto the combustion grate, and the waste is pyrolyzed to generate combustible gas, and the combustion sent from the bottom of the combustion grate The primary air for combustion burns combustible gas and solid content, and a main combustion region is formed in the space immediately above the combustion grate. Further, unburned components such as fixed carbon are completely burned on the post-combustion grate, and a post-combustion region is formed in a space immediately above the post-combustion grate. Thereafter, the ash remaining after combustion is discharged to the outside from the ash drop opening.

  Thus, in the grate-type waste incinerator, the waste is burned by the primary combustion air blown from below the three-stage grate in the combustion chamber. Further, the unburned portion of the combustible gas contained in the combustion gas from the combustion chamber receives and burns secondary combustion air in the secondary combustion chamber.

  In a conventional grate-type waste incinerator, the ratio (air ratio) obtained by dividing the amount of air actually supplied into the incinerator by the theoretical amount of air necessary for combustion of the waste is usually about 1.6. . This is larger than 1.05 to 1.2 which is an air ratio necessary for combustion of general fuel. The reason for this is that waste has a higher incombustibility than liquid fuel or gaseous fuel as a general fuel and is inhomogeneous, so the efficiency of air utilization is low, and a large amount of air is required for combustion. It is to become. However, if the supply air is simply increased, the amount of exhaust gas increases as the air ratio increases, and accordingly, a larger exhaust gas treatment facility is required.

  If waste can be burned without any problems in a waste incinerator with a reduced air ratio, the amount of exhaust gas will be reduced, and the exhaust gas treatment facility will become compact. As a result, the entire waste incineration facility will be downsized. Equipment costs can be reduced. In addition, since the amount of chemicals used for exhaust gas treatment is reduced, the operating cost can be reduced. Furthermore, since the heat recovery rate of the waste heat boiler can be improved by reducing the amount of exhaust gas, the amount of heat that can not be recovered and discarded to the atmosphere is reduced, and the efficiency of power generation using waste incineration waste heat is reduced accordingly. Can be raised.

  Thus, the advantage of performing the low air ratio combustion is great, but on the other hand, the low air ratio combustion with the air ratio of 1.5 or less causes a problem that the combustion becomes unstable. In other words, when waste is burned at a low air ratio, combustion becomes unstable, CO generation increases, flame temperature rises locally, NOx increases rapidly, and soot is generated in large quantities. As a result, there is a problem that harmful substances in the exhaust gas increase, and waste and ash melt and adhere to the furnace wall due to local high temperatures, and clinker is generated, and the refractory life of the furnace wall is shortened. There is a problem of becoming.

  Under such circumstances, a waste incinerator capable of stably combusting at a low air ratio of 1.5 or less has been studied and disclosed in Patent Document 1. In this patent document 1, it is said that the following effects can be obtained by blowing high temperature gas into the combustion chamber from the ceiling of the combustion chamber of the waste incinerator.

  That is, promoting the thermal decomposition of waste by sensible heat and radiation of high temperature gas, promoting the combustion of combustible gas generated by thermal decomposition of waste by blowing high temperature gas containing oxygen, Gas is blown into the combustion chamber from the nozzle provided on the ceiling of the combustion chamber, and the flow of this high-temperature gas collides with the upward flow of combustible gas and combustion gas generated from waste, and the flow of gas flows directly above the waste layer. By forming a slow stagnation region, the flow of combustible gas becomes gentle, and the combustible gas is sufficiently mixed with the oxidant component, so that stable combustion is performed, and a flat flame is formed and kept standing. It is said that by burning high temperature gas into the combustion chamber, waste can be stably burned under low air ratio combustion operation.

  In such a grate-type waste incinerator, a dry region, a combustion start region, a main combustion region, and a post-combustion region are sequentially formed in the furnace from the upstream side in the waste movement direction. In the main combustion zone, the waste on the combustion grate is pyrolyzed and partially oxidized to generate a combustible gas, and the combustible gas and the solid content of the waste are combusted. When combustible gas burns, it forms a flame and burns. Thereafter, in the post-combustion region, unburned solids such as fixed carbon in the remaining waste are completely burned on the post-combustion grate. When solids burn, no flame is generated and soot burns.

  The main combustion region is a combustion region in which waste is thermally decomposed and partially oxidized to generate a combustible gas, and the combustible gas is combusted with a flame and the solid content of the waste is combusted. . The point at which combustion with a flame is substantially completed is called a burnout point, and becomes a boundary between the main combustion region and the post-combustion region. In the area after the burn-off point, a soot combustion area (post-combustion area) in which the unburned solid content in the waste is combusted.

  By grasping the position of this burn-off point in the incinerator, the position of the boundary between the main combustion region and the post-combustion region can be grasped. The fact that the position of the fuel cut point is at a predetermined position indicates that the main combustion region and the post-combustion region are formed in a preferable range, and the combustion of waste is performed without any trouble.

  Patent Document 2 discloses a method for detecting the position of a fuel cut point. In this patent document 2, the image of the in-furnace image obtained by photographing the inside of the incinerator with the ITV camera is image-processed, and the region of the flame part is extracted by using the tendency of the brightness distribution of the in-furnace image. Is going to be detected. The ITV camera is directed from the rear end position of the furnace to the upstream side in the direction of movement of the waste on the grate to photograph the flame part.

JP2013-213652A JP 2000-179820 A

  In the combustion of waste in a waste incinerator, stable combustion of combustible gas generated by thermal decomposition of the waste suppresses the generation of harmful substances such as CO and NOx generated by the combustion. To make a big contribution. Therefore, in the waste incinerator described in Patent Document 1, high temperature gas is blown into the combustion chamber from a nozzle provided on the ceiling of the combustion chamber to stabilize combustion.

  According to such a waste incinerator of Patent Document 1, the high-temperature gas blown from the ceiling of the incinerator is increased in pyrolysis gas (combustible gas) and combustion gas generated by pyrolysis or combustion of waste. The counter flow field is effectively formed by colliding with the flow, and the stagnation region or the vertical circulation region is generated over a wide area. As a result, the flow of the combustible gas becomes gentle in the stagnation region or the circulation region, and stable combustion is performed. The flame is fixed in a flat shape, and an extremely stable combustion state is maintained.

  In addition, the position of this fuel cut point in the incinerator is grasped, and that the position of the fuel cut point is a predetermined position, the main combustion region and the post combustion region are formed in a preferable range, and the combustion of waste is It is said that it is done without hindrance.

  However, in a waste incinerator where high temperature gas is blown from the furnace ceiling as described in Patent Document 1, the in-furnace photographed image as in Patent Document 2 is image-processed to extract the flame area and When trying to apply the method of detecting the position, the following problems occur. That is, the flow of high-temperature gas blown from the furnace ceiling collides with the upward flow of combustible gas and combustion gas generated from waste, and forms a stagnation region where the flow is slow immediately above the waste layer. A flame is formed and settled and stable combustion is possible, but the flame in the incinerator forms a flat flame, so even if taken from the rear end position of the furnace toward the upstream side, It is difficult to accurately detect the position of the burnout point from the photographed image because only the image in which the range from the side to the downstream side is overlapped and the image becomes a narrow range in the vertical direction.

  In view of such circumstances, the present invention provides a grate-type waste incinerator and a waste incineration method capable of accurately detecting the position of a fuel cut point in a waste incinerator that blows high-temperature gas from the furnace ceiling. The task is to do.

  According to the present invention, the above-described problems are solved by the following configuration regarding the grate-type waste combustion furnace and the waste incineration method.

<Grate-type waste incinerator>
A grate-type waste incinerator comprising a grate and a combustion chamber for burning waste on the grate, and primary air blowing means for blowing primary air for combustion into the combustion chamber from under the grate And a high temperature gas blowing means for blowing high temperature gas downward from the ceiling of the combustion chamber, the furnace temperature in the furnace length direction, which is the direction of movement of waste on the grate, A fuel cut point position detecting means for detecting the highest position as a fuel cut point position is provided, and the high temperature gas blowing means is provided at a plurality of positions in the furnace length direction of the ceiling of the combustion chamber. And a high-temperature gas supply means for supplying a high-temperature gas to the high-temperature gas inlet, the fuel cut point position detecting means is adjacent in the furnace length direction within the range from the dry grate to the post-combustion grate The position between the hot gas inlets A fuel cut-off point position that determines the position of a plurality of temperature detection means arranged at the front position of the inlet and the rear position of the last hot gas inlet and the temperature detection means showing the highest temperature as the fuel cutoff point A grate-type waste incinerator comprising a determination unit.

<Waste incineration method>
A waste incineration method using a grate-type waste incinerator having a combustion chamber, in which primary air for combustion is blown into the combustion chamber from below the grate, and the movement direction of the waste on the grate on the ceiling of the combustion chamber In the waste incineration method in which high temperature gas is blown downward from high temperature gas injection ports provided at a plurality of positions in the furnace length direction, adjacent in the furnace length direction within the range from the dry grate to the post-combustion grate Temperature detection that detects the temperature at each position by a plurality of temperature detection means arranged at the position between the hot gas inlets, the front position of the frontmost hot gas inlet, and the rear position of the last hot gas inlet A waste incineration method comprising: a step, and a fuel cut-off point position determination step of determining a position of a temperature detecting means showing the highest temperature as a fuel cut-off point.

  As described above, in the present invention, in the grate waste incinerator and the waste incineration method in which high temperature gas is blown from the furnace ceiling, in the furnace length direction, adjacent in the range from the dry grate to the post-combustion grate. The temperature is detected at each position by a plurality of temperature detection means arranged at the position between the hot gas inlets, the front position of the frontmost hot gas inlet, and the rear position of the last hot gas inlet. It becomes possible to determine the position of the temperature detecting means indicating the temperature of the temperature as the burn-out point.

  In the present invention, since the high temperature gas is blown from the ceiling of the combustion chamber, the following effects are obtained.

[Combustion stabilization effect by high-temperature gas injection]
Combustion generated by thermal decomposition of waste can be promoted by injecting hot gas downward from the blow-off port provided on the ceiling of the combustion chamber of the waste incinerator and promoting sensible heat and radiation of the hot gas. In addition, the downward flow of the hot gas and the upward flow of the combustible gas generated from the waste layer collide with the upward flow of the combustion gas, and the gas flow directly above the waste layer. Can be formed over a wide range in the width direction and the length direction of the combustion chamber, so that stable combustion is performed, and a planar combustion region (flame) Can be established. Further, the thermal decomposition of the waste can be further promoted by radiation of a standing flat flame or the like. Thus, by blowing high-temperature gas, waste and generated combustible gas can be stably burned even in low air ratio combustion where the air ratio is 1.5 or less, regardless of the size of the incinerator. And since combustion is stabilized, the generation amount of harmful substances such as CO and NOx in the exhaust gas discharged from the waste incinerator can be suppressed.

  As described above, by blowing high temperature gas, for example, even in low air ratio combustion where the air ratio is 1.5 or less, waste and generated combustible gas can be stably burned and discharged from the waste incinerator. It is possible to suppress the amount of harmful substances such as CO and NOx in the exhaust gas. In addition, because thermal decomposition and combustion of waste can be promoted, the volume of the combustion chamber can be reduced relative to the amount of waste incineration, the furnace height of the incinerator can be reduced, and waste incineration can be achieved. Equipment costs and operating costs can be reduced by making the equipment compact.

BRIEF DESCRIPTION OF THE DRAWINGS The outline structure of the waste incinerator which concerns on one Embodiment of this invention is shown, (A) is a longitudinal cross-sectional view in a furnace length direction, (B) is a BB arrow line view in (A). It is sectional drawing of the furnace width direction explaining the combustion state in the waste incinerator shown in FIG.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. The technical scope of the present invention is not limited by these embodiments, and can be implemented in various forms without changing the gist of the invention. Further, the technical scope of the present invention extends to an equivalent range.

  Hereinafter, the basic configuration, each component device, and operation of the grate-type incinerator of one embodiment of the present invention will be described.

<Basic configuration of grate-type incinerator>
1A and 1B show a schematic configuration of a waste incinerator according to an embodiment of the present invention. First, a basic configuration of a waste incinerator and an overview of an incineration method according to an embodiment of the present invention will be described, and then details of each component device will be described. In this embodiment, the upstream side of the combustion chamber in the movement direction (furnace length direction) of the waste in the combustion chamber is referred to as a front portion, and the downstream side is referred to as a rear portion.

  The waste incinerator 1 according to the present embodiment is disposed above the combustion chamber 2 and the upstream side of the combustion chamber 2 in the flow direction of waste (left side in FIG. 1A), and the waste is disposed in the combustion chamber 2. A grate provided with a waste inlet 3 for charging into the inside, and a waste heat boiler 4 provided continuously above the downstream side of the combustion chamber 2 in the waste flow direction (the right side of FIG. 1A) It is a type incinerator.

  At the bottom of the combustion chamber 2, there is provided a grate (stoker) 5 that burns while moving the waste. The grate 5 is provided in the order of the dry grate 5a, the combustion grate 5b, and the post-combustion grate 5c from the side closer to the waste inlet 3, that is, from the upstream side. A waste layer W is formed on the lattice 5b.

  In the dry grate 5a, waste is mainly dried and ignited. In the combustion grate 5b, waste is thermally decomposed and partially oxidized, and the combustible gas and solid matter generated by the thermal decomposition are combusted. When the combustible gas burns, a flame is formed. On the post-combustion grate 5c, the unburned solids in the remaining waste are completely burned. When the solids in the waste burn, no flame is generated and the soot burns. The combustion ash after complete combustion is discharged from the ash drop opening 6.

  In the incinerator of this embodiment, the following regions are formed in the space in the combustion chamber 2 and in the space immediately above the waste layer.

  A dry region A1 is formed above the upstream range (front part) of the dry grate 5a in the waste flow direction, which is positioned directly above the dry grate 5a and below the waste input port 3. Is done.

  A combustion start region A2 is formed above the upstream range (front part) of the combustion grate 5b from the downstream range (rear part) of the dry grate 5a. That is, the waste in the dry grate 5a is dried in the upstream range, ignited in the downstream range, and combustion starts in the range up to the upstream range (front) of the combustion grate 5b.

  The waste on the combustion grate 5b is thermally decomposed and partially oxidized here to generate a combustible gas, and the combustible gas and the solid content of the waste are combusted. The waste is substantially burned on the combustion grate 5b. Thus, the main combustion region A3 is formed above the combustion grate 5b.

  Thereafter, the unburned matter such as fixed carbon in the remaining waste is completely burned on the post-burning grate 5c. A post-combustion region A4 is formed above the post-combustion grate 5c.

  When the waste is incinerated, water evaporation occurs first, followed by thermal decomposition and partial oxidation reaction, and combustible gas begins to be generated. Here, the combustion start area A2 is an area where combustion of waste starts and combustible gas begins to be generated by thermal decomposition and partial oxidation of the waste. The main combustion region A3 is a combustion in which waste is thermally decomposed and partially oxidized to generate a combustible gas, and the combustible gas is combusted with a flame and the solid content of the waste is combusted. This is an area up to the point where the combustion with the flame is completed (burn-off point). In the area after the burnout point, the soot combustion area (post-combustion area A4) in which the solid unburned matter in the waste is combusted.

  The dry region A1, the combustion start region A2, the main combustion region A3, and the post-combustion region A4 will be described later again.

  Wind boxes 7a, 7b, 7c, and 7d are provided below the dry grate 5a, the combustion grate 5b, and the post-combustion grate 5c in the combustion chamber 2, respectively. The combustion primary air P supplied by the blower 8 is supplied to the wind boxes 7a, 7b, 7c and 7d through the combustion primary air supply pipe 9, and combusts through the fire grates 5a, 5b and 5c. It is supplied into the chamber 2. The primary combustion air P supplied from below the grate is used for drying and burning the waste on the grate 5a, 5b, 5c, cooling action of the grate 5a, 5b, 5c, Has a stirring action.

  A waste heat boiler 4 is connected to an outlet on the downstream side of the combustion chamber 2, and an unburned portion (unburned gas) of the combustible gas in the gas discharged from the combustion chamber 2 near the inlet of the waste heat boiler 4. It becomes the secondary combustion area | region 10 which burns. The secondary combustion gas is blown into the secondary combustion region 10 which is a part of the waste heat boiler, and the unburned gas is subjected to secondary combustion. After this secondary combustion, the combustion exhaust gas is recovered by the waste heat boiler 4 as heat. . After heat recovery, the combustion exhaust gas discharged from the waste heat boiler is neutralized with acid gas by slaked lime, etc. and dioxins are adsorbed by activated carbon in an exhaust gas treatment system (not shown), and further to a dust removal equipment (not shown). The neutralized reaction product, activated carbon, dust and the like are collected. The combustion exhaust gas that has been dedusted and detoxified by the dust removing device is attracted by an attraction fan (not shown) and released from the chimney into the atmosphere. Further, a part of the combustion exhaust gas after being dust-removed by the dust removing device is used as a return exhaust gas to be described later.

In the grate-type incinerator having such a basic configuration, the waste incinerator 1 according to the present embodiment includes a primary air blowing unit that blows primary combustion air into the combustion chamber from below the grate, and a furnace A plurality of hot gas blowing ports in the longitudinal direction, and hot gas blowing means for blowing the hot gas downward from the ceiling of the combustion chamber.

<Primary air blowing means>
In the present embodiment, the waste incinerator 1 includes a primary air supply system of primary air that serves as combustion air. The primary air supply system passes the primary air P from the air supply source through the primary air supply pipe 9 for combustion, and the wind boxes 7a, 7b, 7c of the dry grate 5a, the combustion grate 5b, and the post-combustion grate 5c, respectively. , 7d from the branch supply pipe, and the combustion primary air supply pipe 9 is provided with a blower 8 and a damper 11 as a flow rate adjusting mechanism.

<High-temperature gas blowing means>
In the present embodiment, the waste incinerator 1 includes a high temperature gas blowing means for blowing a high temperature gas downward from the ceiling of the combustion chamber. The hot gas blowing means includes a plurality of hot gas blowing ports in the furnace length direction, which is the moving direction of the waste on the grate, and a hot gas supply means for supplying the hot gas to the hot gas blowing port. An inlet is provided in the ceiling from the rear of the dry grate to the front of the rear combustion grate.

  In the present embodiment, the high temperature gas blowing means includes a high temperature gas supply device 24 provided outside the combustion chamber 2, a high temperature gas blowing port 13 for blowing high temperature gas into the combustion chamber 2, and a damper 14 as a flow rate adjusting mechanism. And a conduit for guiding the high temperature gas to the high temperature gas inlet 13.

  The hot gas supply device 24 mixes return exhaust gas and hot air to prepare a hot gas, and supplies the hot gas to the hot gas inlet 13. Here, the “returned exhaust gas” is a part of the exhaust gas after the exhaust gas discharged from the incinerator is neutralized by the exhaust gas treatment system and removed by the dust removing device. The high-temperature air is generated by heating air with a heater. The hot gas supply device 24 adjusts the mixing ratio by adjusting the flow rates of the return exhaust gas and the hot air to adjust the temperature and oxygen concentration of the hot gas. Moreover, the high temperature gas supply device 24 may supply only high temperature air or only return exhaust gas as a high temperature gas.

  The high temperature gas supplied from the high temperature gas supply means preferably has an oxygen concentration of 5 to 21 dry volume%, more preferably 12 to 21 dry volume%.

Hot gas blowing port 13, the ceiling of the combustion chamber 2, up to the moving direction of the waste drying grate 5a (furnace length direction) downstream the upstream side of the post-combustion grate 5 c from (posterior) (front) It is provided at a position just above the grate within the range. Moreover, the high temperature gas injection port 13 (13a, 13b, 13c, 13d) is arrange | positioned in the multiple positions (four places) of the furnace length direction within said range.

  In the hot gas blowing means, the direction of the hot gas blowing port 13 is determined so that the hot gas is blown downward. Thus, the high-temperature gas is provided from the high-temperature gas inlet 13 so as to blow from the combustion start region A2 toward the front region of the post-combustion region A4. Moreover, the hot gas from the hot gas blowing port 13d located on the most downstream side may be blown toward the region immediately after the fuel cut point.

  As shown in FIG. 2, the high-temperature gas inlets 13 are provided at a plurality of locations also in the furnace width direction (a direction perpendicular to the paper surface in FIG. 1A and a vertical direction in FIG. 1B). ing. Moreover, the high temperature gas injection port 13 may be arrange | positioned in the several position of a furnace length direction, respectively within said range (refer FIG. 1 (B)).

<Flame cut point detection means>
In the main combustion region A3, the waste is thermally decomposed and partially oxidized to generate a combustible gas. The combustible gas is combusted with a flame and the solid content of the waste is combusted. The detection of the position of the burnout point, which is the point at which combustion with a flame is substantially completed, will be described. The burnout point is the boundary between the main combustion region and the post-combustion region. In the area after the burn-off point, a soot combustion area (post-combustion area) in which the unburned solid content in the waste is combusted. In the furnace length direction, the furnace temperature changes in the range from the drying area A1 to the post-combustion area A4 in the furnace, and combustion with a flame is substantially completed at the fuel cut point, and the furnace temperature becomes the highest. In this embodiment, it has the fuel cut point position detection means which detects the position of the fuel cut point in the furnace length direction, and the fuel cut point position control means which controls the position.

  The fuel cut point position detection means includes a plurality of temperature detection means and a fuel cut point position determination means.

  The temperature detecting means includes a position between adjacent hot gas inlets in the range from the dry grate to the post-combustion grate in the furnace length direction, a front position of the frontmost hot gas inlet, and the last hot gas. A plurality of them are arranged in each of the rear positions of the air inlets. The fuel cut point position determining means determines the position of the temperature detecting means showing the highest temperature among the plurality of temperature detecting means as the fuel cut point.

  In FIG. 1B, the plurality of temperature detecting means 16a to 16e, for example, thermocouples, are provided on both side walls facing each other in the furnace width direction.

  As shown in FIG. 1B, two rows of hot gas inlets 13a to 13d provided at intervals in the furnace length direction are provided at intervals in the furnace width direction. The temperature detecting means 16a to 16e provided in the are disposed between the high-temperature gas injection ports 13a and 13b adjacent in the furnace length direction, between 13b and 13c, between 13c and 13d, and the foremost high-temperature gas injection port 13a. Are arranged at the respective positions in front of and behind the last hot gas inlet 13d. Thus, the in-furnace temperature at each position is detected by each temperature detecting means 16a to 16e.

  The temperature detecting means 16a to 16e are preferably provided on both side walls as illustrated in the case of a large furnace having a large furnace width, but provided on one side wall in the case of a small furnace having a small furnace width. It is also good.

  Although not shown, the fuel cut point position determination means has a determination means for determining the position in the furnace length direction of the temperature detection means that has detected the maximum temperature as the fuel cut point from the detected temperatures received from the temperature detection means 16a to 16e. doing.

  In the present embodiment, as described above, the temperature detection means 16a to 16e are used for relative comparison determination by comparing the temperatures of the temperature detection means in order to find the position of the highest furnace temperature in the furnace length direction. Yes, not to know the absolute value of the temperature itself. Therefore, it is sufficient for all the temperature detection means to be disposed at the same furnace height direction position and furnace width direction position. Moreover, it is preferable that the furnace height direction position of the temperature detection means is an upper position within 1 m from the upper surface of the waste layer so that the temperature detection means does not contact the waste layer deposited on the grate.

<Flame cut point position control means>
The fuel cut point position control means (not shown) has a combustion operation amount adjusting means for operating the state of combustion of waste, and is based on the fuel cut point position information output from the fuel cut point position determination means. It can be controlled by an operation by the combustion operation amount adjusting means so that the cut point is a predetermined position. When the fuel cut point determined by the fuel cut point position determining unit is different from the predetermined position, the combustion operation amount adjusting unit adjusts the combustion operation amount as described below, thereby setting the fuel cut point to the predetermined position. Control to do.

  The combustion operation amount adjustment means of the fuel cut point position control means is means for adjusting at least one of the feed rate of the grate 5 (5a to 5c) and the amount of primary air P injected. Adjustment of the amount of blowing in primary air P is performed, for example, by adjusting the opening degree of dampers 7a-1 to 7d-1 provided in wind boxes 7a to 7d, respectively.

  When it detects that waste with high calorific value (calorie), that is, low moisture content, has been supplied to the combustion chamber by changing the amount of evaporation of the boiler, the fuel cut point position is moved to the predetermined position In order to perform the control, the waste on the grate is agitated by increasing the feed rate of the grate 5 to promote the drying / combustion of the waste, or the drying grate and the combustion grate of the primary air P Control to move the fuel cut point position to the upstream side by increasing the amount blown into the rear and reducing the amount blown into the post-combustion grate to promote waste drying and combustion . Further, in order to move the fuel cut point position to the downstream side and control it to a predetermined position, the stirring speed of the waste on the grate is suppressed by slowing the feed rate of the grate 5, and the drying / To mitigate combustion, or to reduce the amount of primary air P blown into the dry grate and increase the amount blown into the combustion grate and post-combustion grate to mitigate waste drying and combustion Control which moves a fuel cut point position to the downstream is performed by at least one of these.

  When detecting that the waste with a low calorific value (calorie), that is, with a large amount of moisture, has been supplied to the combustion chamber by fluctuations in the amount of evaporation of the boiler, etc., the fuel cut point position is moved upstream to a predetermined position. In order to perform the control, the residence time of the waste on the grate is increased by slowing the feed rate of the grate 5 to reliably dry and burn the waste, or the dry grate of the primary air P Increase the amount of fuel injected into the combustion grate and decrease the amount of injection into the post-combustion grate to promote the drying and combustion of waste and move the fuel cut point position upstream. To control. In addition, in order to control the fuel cut point position to the downstream side to make it a predetermined position, the residence time of the waste on the grate is shortened by increasing the feed rate of the grate 5 and the waste is dried.・ Mitigate combustion, or reduce the amount of primary air P blown into the dry grate and increase the amount blown into the combustion grate and post-combustion grate to mitigate waste drying and combustion Control which moves a fuel cut point position to the downstream is performed by at least one of these.

  In the present embodiment, the fuel cut point position control means sets the predetermined position of the fuel cut point position to the rearmost position of the combustion grate 5b or the boundary position between the combustion grate 5b and the rear combustion grate 5c.

<Secondary combustion gas supply means>
Further, the waste incinerator 1 of the present embodiment includes a secondary combustion gas supply system that blows the secondary combustion gas into the secondary combustion region 10 corresponding to the vicinity of the inlet of the waste heat boiler 4. The secondary combustion gas supply system feeds the secondary combustion gas Q from the secondary combustion gas supply source to the secondary combustion gas inlet 17 provided in the secondary combustion region 10 via the pipe 12. The pipe 12 is provided with a blower 18 and a damper 19 as a flow rate adjusting mechanism. The secondary combustion gas inlet 17 is provided on the peripheral wall of the waste heat boiler 4 so as to blow the secondary combustion gas Q into the secondary combustion region 10 in the vicinity of the inlet of the waste heat boiler 4. Most of the combustible gas generated in the combustion chamber 2 is combusted in the combustion chamber 2, and the remaining unburned gas corresponds to the vicinity of the inlet of the waste heat boiler 4 connected above the post-combustion grate 5c. The gas flows into the secondary combustion region 10 where secondary combustion gas is supplied and secondary combustion is performed.

  In the present invention, the configuration of the pipeline for supplying the primary air for combustion, the high-temperature gas, and the secondary combustion gas is not limited to those shown in the drawings, and may be appropriately selected depending on the scale, shape, application, etc. Can be selected.

  Next, an overview of the incineration situation in the apparatus of the present embodiment configured in this way, fuel cut point position detection, fuel cut point position control, combustion primary air, hot gas, combustion secondary air blowing The operation will be described sequentially.

<Overview of incineration>
First, when waste is input into the waste input port 3, the dropped waste is supplied into the combustion chamber 2 by a waste supply device (not shown) and deposited on the dry grate 5a. The operation moves onto the combustion grate 5b and onto the post-combustion grate 5c, forming a waste layer on each grate. Each grate receives the primary air for combustion via the wind boxes 7a, 7b, 7c, 7d, whereby the waste in each grate is dried and burned.

  Wastes are mainly dried and ignited on the dry grate 5a. That is, the waste of the dry grate 5a is dried in the upstream range of the dry grate 5a, ignited in the downstream range of the dry grate 5a, and up to the upstream range (front part) of the combustion grate 5b. Combustion starts in the range. A dry region A1 is formed above the upstream range (front part) of the dry grate 5a in the waste flow direction. A combustion start region A2 is formed above the upstream range (front part) of the combustion grate 5b from the downstream range (rear part) of the dry grate 5a. On the combustion grate 5b, pyrolysis and partial oxidation of waste are mainly performed to generate a combustible gas. The combustible gas burns with a flame, and solids in the waste are combusted. A main combustion region A3 is formed above the combustion grate 5b. This combustion region is a region up to a point (combustion point) where combustion with a flame is completed. The combustion of the waste is substantially completed on the combustion grate 5b. On the post-combustion grate 5c, unburned components such as fixed carbon in the remaining waste are completely burned. In the region after the burn-off point, the solid unburned portion (char) in the waste is burned, and a post-combustion region A4 is formed above the post-combustion grate 5c. The combustion ash after complete combustion is discharged from the ash drop opening 6. With the waste burning in this manner, as seen in FIG. 1, the space immediately above each grate 5a, 5b, 5c has a dry region A1, a combustion start region A2, a main combustion region A3, and a rear region. A combustion region A4 is formed.

  As described above, the waste heat boiler 4 is connected to the outlet of the combustion chamber 2, and the vicinity of the inlet of the waste heat boiler 4 is the secondary combustion region 10. Therefore, the unburned portion (unburned gas) of the combustible gas generated in the combustion chamber 2 is guided to the secondary combustion region 10 where it is mixed and stirred with the secondary combustion gas Q, and is subjected to secondary combustion. After the secondary combustion, the exhaust gas is recovered by the waste heat boiler 4. After heat recovery, the exhaust gas discharged from the waste heat boiler 4 is neutralized with acid gas by slaked lime, adsorbed dioxins with activated carbon, and sent to a dust removal device (not shown). The reaction product, activated carbon, dust, etc. are recovered. The exhaust gas that has been dedusted and detoxified by the dust remover is attracted by an attracting fan (not shown) and released from the chimney into the atmosphere. In addition, as said dust removal apparatus, dust removal apparatuses, such as a bag filter system and an electrostatic dust collection system, can be used, for example. Further, a part of the exhaust gas after being removed by the dust removing device is used as the return exhaust gas.

<Fuel cut point position detection>
As described above, when the waste burns on the grate 5 (5a to 5c), a plurality of temperature detecting means 16a to 16e provided on the side wall of the furnace at the upper position of the grate by the burnout point position detecting means. In each case, the temperature at each position in the furnace length direction is detected. As described above, the fuel cut point position detection means also has a fuel cut point position determination means, and in the furnace length direction of the temperature detection means that detects the highest temperature among the temperature detection means 16a to 16e. Is determined to be the burnout point position.

<Fire cut point position control>
When the fuel cutoff point position is obtained by the fuel cutoff point position determining means, the fuel cutoff point position control means is controlled so that the position becomes a predetermined position. The control is performed by the combustion operation amount adjusting means of the fuel cut point position control means.

  In the present embodiment, the predetermined position is set at the rearmost position of the combustion grate 5b or the boundary position between the combustion grate 5b and the post-combustion grate 5c. The combustion state is manipulated by performing at least one of the adjustment of the feed speed 5c and the opening adjustment of the dampers 7a-1 to 7d-1 for adjusting the flow rate.

  When detecting that the waste with high calorific value (calorie), that is, low moisture content is supplied to the combustion chamber by fluctuation of boiler evaporation, etc., the determined fuel cut point is downstream from the predetermined position. In order to control the fuel cut point position to the upstream position, the waste on the grate is stirred by increasing the feed rate of the grate 5 to promote the drying and combustion of the waste. Or increasing the amount of primary air P blown into the dry grate and combustion grate and reducing the amount blown into the post-combustion grate to promote the drying and combustion of waste Thus, the fuel cut point position is moved to the upstream side and controlled to a predetermined position.

  Further, in order to control the determined fuel cut point upstream from the predetermined position and move the fuel cut point position to the downstream side to make the predetermined position, the grate can be controlled by slowing the feed rate of the grate 5 Suppressing the agitation of the above waste and mitigating the drying and combustion of the waste, or reducing the amount of primary air P blown into the dry grate and the amount blown into the combustion grate and post-combustion grate In order to reduce the drying / combustion of the waste and control the fuel cut point position to the downstream side to achieve a predetermined position.

  When the amount of calorific value (calorie) is low, that is, when waste with a large amount of water is supplied to the combustion chamber is detected by fluctuations in the amount of boiler evaporation, the determined fuel cut-off point is downstream of the predetermined position. In order to control the fuel cut point position to the upstream side to make it a predetermined position, the residence time of the waste on the grate is increased by slowing the feed rate of the grate 5, and the waste drying / Increase the amount of primary air P blown into the dry grate and combustion grate and reduce the amount blown into the post-combustion grate to promote the drying and combustion of waste. By at least one of the above, control is performed to move the fuel cut point position to the upstream side so as to be a predetermined position.

  Further, in order to control the determined fuel cut point upstream from the predetermined position and move the fuel cut point position downstream to the predetermined position, the waste is increased by increasing the feed rate of the grate 5 The residence time on the grate is shortened to reduce the drying / combustion of the waste, or the amount of primary air P blown into the dry grate is reduced and blown into the combustion grate and the post-combustion grate By increasing the amount and at least one of reducing the drying / combustion of the waste, the fuel cut-off point position is moved to the downstream side and controlled to a predetermined position.

  Thus, the fuel cut point determined by the fuel cut point position determination means is controlled to be a predetermined position. By setting the fuel cut point to a predetermined position, the main combustion region and the post-combustion region are formed in a preferable range, and the combustion of waste is stably performed.

<Blowing primary air for combustion>
The primary air P for combustion passes from the blower 8 through the primary air supply pipe 9 for combustion, and wind boxes 7a, 7b, 7c provided at the lower portions of the dry grate 5a, the combustion grate 5b, and the post-combustion grate 5c, respectively. , 7d and then supplied into the combustion chamber 2 through the grate 5a, 5b, 5c. The flow rate of the combustion primary air P supplied into the combustion chamber 2 is adjusted by a flow rate adjusting damper 11 provided in the combustion primary air supply pipe 9, and further a command from the fuel cut point position control means. Based on the above, the flow rate supplied to each wind box 7a, 7b, 7c, 7d is adjusted by the dampers 7a-1 to 7d-1 provided in the respective supply pipes that are branched from each wind box. Further, the configurations of the air boxes 7a, 7b, 7c, 7d and the combustion primary air supply pipe 9 for supplying the combustion primary air P are not limited to those shown in the figure, but the incinerator scale, shape, application, etc. Can be appropriately selected.

  As the primary air P for combustion, it is preferable to use a gas having a temperature in the range of room temperature to 200 ° C. and an oxygen concentration in the range of 15 to 21 dry volume%. As the primary air P for combustion, any one of air, oxygen-containing gas and return exhaust gas may be used, or a mixed gas thereof may be used.

<Combustion stabilization by hot gas injection>
As shown in FIG. 1A, hot gas is blown from the hot gas inlet 13 (13a, 13b, 13c, 13d) from the combustion start region A2 toward the front region of the rear combustion region A4. , Blown downward toward the waste layer W. In order to stabilize the combustion, it is preferable to blow high-temperature gas into a region where there is a flame and a large amount of combustible gas. Therefore, before the combustion start region A2 which is a region where a large amount of combustible gas is present, Hot gas is blown into the area up to the section.

  The hot gas is blown downward from the hot gas blowing port 13 by blowing the hot gas downward into the region from the combustion start region A2 in the combustion chamber 2 to the front portion of the post-combustion region A4 and directly above the waste layer W. The high-temperature gas is opposed to the upward flow of combustible gas and combustion gas generated by thermal decomposition and partial oxidation of waste, and both gas flows collide with each other, and the flat flow is slow immediately above the waste layer W. A stagnation region or a circulation region that circulates in the vertical direction is generated. Since the gas flow speed is slow in these regions, a flame in which the combustible gas burns is fixed, that is, a planar combustion region (planar flame) E (see FIG. 2) is defined immediately above the waste layer W. Present, and combustible gas is stably burned.

  In addition to the fact that wastes are heated by thermal radiation and sensible heat of high-temperature gas, and thermal decomposition and partial oxidation are promoted, a planar combustion region (planar flame) is present directly above the waste layer. The waste is heated by thermal radiation and sensible heat from the flat flame, and thermal decomposition and partial oxidation are further promoted. In addition, the combustion of the combustible gas generated by the thermal decomposition of the waste is promoted by blowing in the high-temperature gas containing oxygen.

  Thus, the waste W can be stably burned even under the low air ratio combustion operation. As a result, it is possible to suppress the generation of harmful substances such as CO, NOx, and dioxins even in low air ratio combustion. For this reason, low air ratio combustion can be performed without hindrance.

  Next, the preparation of the high-temperature gas, the blowing port, the blowing flow velocity / blowing amount, and the blowing of the secondary combustion gas will be sequentially described.

<Preparation of hot gas>
The temperature of the hot gas blown from the hot gas blowing port 13 is preferably in the range of 100 to 400 ° C, more preferably about 150 to 200 ° C. When a gas having a temperature of less than 100 ° C. is blown, the temperature in the furnace decreases, combustion becomes unstable, and the amount of CO generated increases. When a gas exceeding 400 ° C. is blown, the flame temperature in the combustion chamber becomes extremely high, which causes problems such as promotion of clinker generation. By setting the temperature of the high-temperature gas to about 150 to 200 ° C., the occurrence of the above-described problem can be suppressed and the energy for heating the air can be set to an appropriate range, which is more preferable.

  Moreover, it is preferable that the oxygen concentration of the high temperature gas blown from the high temperature gas blowing port 13 is adjusted to 5 to 21 dry volume%, more preferably to 12 to 21 dry volume%. Thereby, the above-mentioned effect is exhibited more effectively, and the reduction of NOx and the reduction of CO of exhaust gas is further promoted.

  The grounds for setting the oxygen concentration of the high-temperature gas in the above range are as follows. If the oxygen concentration of the high-temperature gas is lower than the lower limit, the region from the combustion start region A2 to the main combustion region A3 becomes excessively low-oxygen atmosphere due to the high-temperature gas blowing, and the amount of combustible gas generated by the thermal decomposition of the waste Is unsuitable because the amount of unburned combustible gas (unburned gas) that flows into the secondary combustion region without being burned in the combustion chamber becomes excessive, and is unsuitable. If the oxygen concentration is higher than the upper limit, Combustion of the combustible gas is excessive and a high temperature field is generated, and the amount of NOx generated is unsuitable. Therefore, the oxygen concentration of the high temperature gas is preferably 5 to 21 dry volume%, and the oxygen concentration of 12 to 21 dry volume% This is more preferable because the problem can be reliably avoided.

In this embodiment, a mixed gas or high-temperature air of return exhaust gas and high-temperature air that returns a part of the exhaust gas discharged from the incinerator is used as the high-temperature gas so that the high-temperature gas has the gas temperature and oxygen concentration described above. I can . As the return exhaust gas, a part of the exhaust gas that has been subjected to neutralization treatment of acid gas, dioxins treatment, and dust removal treatment by the above-described exhaust gas treatment system and dust removal device is used for the exhaust gas discharged from the incinerator. . The high-temperature air is generated by heating air by heat exchange with steam generated by a waste heat boiler. In this embodiment, the return exhaust gas, the return exhaust gas and high-temperature air mixed gas, and the high-temperature air are heated by heat exchange with the steam generated in the waste heat boiler as necessary, and the temperature and oxygen concentration are set to the predetermined values. It is blown into the combustion chamber as a high-temperature gas that satisfies the following conditions.

  In this way, adjusting the mixing ratio of the return exhaust gas and hot air when preparing the high temperature gas, the return exhaust gas, the return exhaust gas and high temperature air mixed gas, the heating conditions of the high temperature air, etc., the temperature of the high temperature gas, oxygen Bring the concentration to the desired range.

<High temperature gas inlet>
Hot gas blowing port 13, the ceiling of the combustion chamber 2, within the scope of the downstream side in the movement direction of the waste drying grate 5a from (posterior) to the moving direction upstream side of the post-combustion grate 5c (front) It is provided at a position directly above the grate.

A plurality of hot gas inlets 13 are arranged in the width direction of the combustion chamber 2 . Atsushi Ko gas injection port 13 can be a slit type in nozzle type.

  The state of the flow of high-temperature gas facing the upward flow from the waste is made favorable so that a planar combustion region is formed over a wide range in the width direction and the furnace length direction directly above the waste layer in the combustion chamber In order to control, at least one of the arrangement position, the number of arrangements, the arrangement interval, the blowing direction, the shape of the blowing port, the blowing flow rate and the blowing flow rate of the hot gas is set or adjusted.

  In FIG. 1, the hot gas is blown downward from the hot gas blowing port 13 toward the waste layer. Here, as a blowing direction of the high temperature gas, it is desirable to blow in a blowing direction in an angle range from a perpendicular to the waste layer to 20 °. This is because the flow field generated by the collision of the blown hot gas with the combustible gas generated by thermal decomposition and partial oxidation of waste and the upward flow of the combustion gas is used as the counter flow field. This is because an appropriate counter flow field is not formed when the entraining direction is in a range larger than 20 ° from the perpendicular to the waste layer.

  The high-temperature gas blowing speed is adjusted, for example, by adjusting the opening of the damper 14 as the flow rate adjusting mechanism provided in the pipe line or the flow rate adjustment mechanism of the blower that sends the high-temperature gas to the high-temperature gas supply device 24. It is adjusted by adjusting the flow rate.

  When there are a plurality of high-temperature gas inlets 13 in the furnace width direction or furnace length direction of the combustion chamber, the high-temperature gas does not necessarily have to be injected from each of the high-temperature gas inlets 13 at an equal flow rate. Alternatively, the blowing flow rate from each hot gas blowing port 13 can be changed as appropriate depending on the waste property, amount, waste layer thickness, and the like.

  When there are a plurality of high-temperature gas injection ports 13 in the furnace width direction or the furnace length direction of the combustion chamber, the high-temperature gas does not necessarily have to be injected from each high-temperature gas injection port 13 at an equal flow rate. Depending on the use or waste properties, amount, waste layer thickness, and the like, the flow rate of blow from each hot gas blow-in port 13 can be appropriately changed.

  In response to fluctuations in the amount of combustible gas and combustion gas generated from the waste in the combustion chamber 2, high-temperature gas injection is performed so that the planar combustion region is fixed immediately above the waste layer W without fluctuation. It is preferable to adjust the flow rate. When the state of the planar combustion region changes, the combustion state of the combustible gas changes and the CO concentration, oxygen concentration, etc. in the combustion exhaust gas change, so the CO concentration and oxygen concentration of the exhaust gas discharged from the boiler are monitored as monitoring factors. You may make it adjust the blowing flow rate of hot gas according to the measurement and the change.

  The hot gas blowing flow rate is adjusted, for example, by the high temperature gas supply device 24 adjusting the flow rate by adjusting the blower amount of the blower sending the high temperature gas and the opening degree of the damper 14.

<Injection of secondary combustion gas>
The secondary combustion gas Q is blown into the secondary combustion region 10, and the unburned gas from the combustion chamber 2 is subjected to secondary combustion. As the secondary combustion gas, it is preferable to use a gas having a temperature in the range of room temperature to 200 ° C. and an oxygen concentration in the range of 15 to 21 dry volume%. As the secondary combustion gas, air, a gas containing oxygen, a return exhaust gas, or a mixed gas thereof may be used.

  It is preferable to install one or more secondary combustion gas inlets 17 so that gas can be blown in the direction in which the swirling flow is generated in the secondary combustion region. By blowing the secondary combustion gas Q in the direction in which the swirling flow is generated in the secondary combustion region 10, the gas temperature and oxygen concentration distribution in the secondary combustion region 10 can be made uniform and averaged. Subsequent combustion is performed stably, generation of a local high temperature region is suppressed, and exhaust gas can be further reduced in NOx. Furthermore, since the mixing of the unburned gas and the oxidant is promoted, the combustion stability is improved and complete combustion can be achieved, so that the exhaust gas can be reduced in CO.

  As the secondary combustion gas Q, only the secondary air for combustion supplied by the blower, the gas adjusted by adjusting the oxygen concentration by mixing the diluent with the secondary air for combustion after the blower is supplied, and after passing through the dust removing device Only the return exhaust gas from which a part of the exhaust gas is extracted, or a gas in which the secondary air for combustion and the return exhaust gas are mixed can be used.

  Diluents such as nitrogen and carbon dioxide are conceivable.

  It is preferable to adjust the flow rate of the secondary combustion gas so that the gas temperature in the secondary combustion region 10 is in the range of 800 to 1050 ° C. When the gas temperature in the secondary combustion region 10 is less than 800 ° C., the combustion of the unburned gas becomes insufficient and the CO in the exhaust gas increases. Moreover, when the gas temperature in the secondary combustion area | region 10 exceeds 1050 degreeC, the production | generation of clinker in the secondary combustion area | region 10 will be encouraged, and NOx will increase further.

  As described above, according to the present invention, in the grate waste incinerator and the waste incineration method for blowing high temperature gas from the furnace ceiling, in the furnace length direction, within the range from the dry grate to the post-combustion grate. The temperature is detected at each position by a plurality of temperature detection means arranged at positions between adjacent high temperature gas injection ports, a front position of the frontmost high temperature gas injection port, and a rear position of the last high temperature gas injection port. The position of the temperature detecting means showing the highest temperature is determined as the fuel cut point, and the combustion operation amount adjusting means for operating the combustion state of the waste is operated based on the determination result so that the fuel cut point is set to the predetermined position. Therefore, the position of the fuel cut point is accurately detected, and the operation of the waste incinerator is controlled so that the position of the fuel cut point is a predetermined position, thereby stabilizing the combustion of the waste. Of harmful substances such as CO and NOx The amount can be suppressed, it is possible to carry out without any problems the low air ratio combustion operation.

  According to the present invention, the hot gas is further blown downward from the blow-in opening provided in the ceiling of the waste incinerator combustion chamber, so that the downward flow of the hot gas, the combustible gas generated from the waste layer, and combustion Forming a stagnation area where the gas flow circulates just above the waste layer or a circulation area where it circulates in the vertical direction over a wide range in the width direction of the combustion chamber and the furnace length direction by colliding with the upward flow of gas. Therefore, it is possible to establish a planar combustion zone, and even in the low air ratio combustion where the air ratio is 1.5 or less, regardless of the size of the incinerator, that is, the width and height of the combustion chamber. And the combustible gas generated can be stably burned. And since combustion is stabilized, the generation amount of harmful substances such as CO and NOx in the exhaust gas discharged from the waste incinerator can be suppressed. Furthermore, the thermal decomposition of waste can be promoted by radiation of a standing flat flame, etc., so the amount of waste supplied to the grate (grate load) and the amount of waste heat supplied to the combustion chamber (furnace) Load) can be increased. For this reason, the volume of the combustion chamber can be reduced relative to the amount of waste incineration, the furnace height of the incinerator can be reduced, and the waste incineration equipment can be made compact to reduce equipment costs and operating costs. Can do. Furthermore, since the combustion can be performed at a lower air ratio than before, the total amount of exhaust gas discharged from the incinerator can be further greatly reduced, and a waste incinerator and a waste incineration method that can improve the recovery efficiency of waste heat are provided. The

DESCRIPTION OF SYMBOLS 1 Waste incinerator 2 Combustion chamber 5 Grate 5a Dry grate 5b Combustion grate 5c Post combustion grate 7a-1-7d-1 Combustion operation amount adjustment means (damper)
13 High temperature gas inlet 16a-16e Temperature detection means 24 High temperature gas supply device

Claims (2)

A grate-type waste incinerator,
A combustion chamber comprising a grate and burning waste on the grate;
Primary air blowing means for blowing primary air for combustion into the combustion chamber from under the grate,
In a grate-type waste incinerator having hot gas blowing means for blowing hot gas downward from the ceiling of the combustion chamber,
The fuel cut point position detecting means for detecting the position where the furnace temperature becomes the highest in the furnace length direction which is the moving direction of the waste on the grate as the fuel cut point position,
The high temperature gas blowing means includes a high temperature gas blowing port provided at a plurality of positions in the furnace length direction of the ceiling of the combustion chamber, and a high temperature gas supply unit for supplying a high temperature gas to the high temperature gas blowing port. ,
The burn-off point position detection means includes, in the furnace length direction, positions between adjacent hot gas inlets in the range from the dry grate to the post-combustion grate, the front position of the frontmost hot gas inlet, and the last A plurality of temperature detecting means respectively disposed at the rear position of the high temperature gas inlet, and a fuel cut point position determining means for determining the position of the temperature detecting means showing the highest temperature as the fuel cut point. Grate-type waste incinerator. A waste incineration method using a grate-type waste incinerator with a combustion chamber,
Blow primary air for combustion into the combustion chamber from below the grate,
In the waste incineration method in which hot gas is blown downward from the hot gas blowing port provided at a plurality of positions in the furnace length direction which is the moving direction of the waste on the grate on the ceiling of the combustion chamber,
In the furnace length direction, the position between adjacent hot gas inlets in the range from the dry grate to the post-combustion grate, the front position of the foremost hot gas inlet, and the rear position of the last hot gas inlet A temperature detection step of detecting the temperature at each position by a plurality of temperature detection means respectively disposed in
A fuel cut point position determining step for determining the position of the temperature detecting means showing the highest temperature as the fuel cut point;
A waste incineration method characterized by comprising:

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