JPH0743109B2 - Waste incineration method in waste incinerator equipped with gas mixing device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waste incineration method for a waste incinerator for incinerating general waste, industrial waste, and the like.

[0002]

2. Description of the Related Art In recent years, due to the heavy use of plastics and the progress of OA, etc., soaring and diversifying waste quality in general waste and industrial waste has been serious, and fluctuations in combustion state in the waste incinerator. Is getting fiercer.

Therefore, a part of the combustion gas generated in the incinerator cannot be completely combusted and is discharged while containing dioxin and other harmful gases such as carbon monoxide and unburned oxides such as soot. In some cases, it causes pollution problems for the local residents.

FIG. 6 shows a schematic construction of a conventional stoker type refuse incinerator.

This stoker type refuse incinerator is equipped with an incinerator a.
A water injection type gas cooling chamber is installed above the combustion chamber f. In this stoker-type waste incinerator, the waste grasped by the waste crane (not shown) from the waste pit (not shown) is thrown into the hopper b. The dust thrown into the hopper b is ignited and burned on the dry grate c and the combustion grate d by the primary combustion air (not shown) sent from below the grate c and d, and the remaining difficulty is left. Burned and unburned materials are
The ash cooling tank (not shown) extinguishes and absorbs the high temperature incinerated ash, which is then burnt on the post-combustion device e to be burned out, and then carried out to the outside.

The combustion gas generated by the combustion of waste is
In the upper part of the combustion chamber f, the flame of the primary combustion and the radiant heat from the furnace wall are received, and the secondary combustion is performed by the secondary combustion air supplied from the supply port g. As a result, unburned components contained in the combustion gas are oxidatively burned, and dioxins and odorous components are thermally decomposed and sent to the gas cooling chamber h as exhaust gas. The high-temperature exhaust gas sent to the gas cooling chamber h is cooled by injecting water from the water injection nozzle i, then is sucked by the suction force of the induction blower m through the air preheater j and the dust collector k, and the chimney. is discharged from n.

The secondary combustion air is generally called furnace temperature cooling air, and its supply amount is often adjusted so as to keep the temperature set range of the furnace temperature control alarm meter. In addition, if the temperature inside the furnace does not drop sufficiently even if the maximum supply amount of the above-mentioned temperature cooling air is supplied, and a high temperature alarm is issued, the water injection nozzle in the reactor for the purpose of reducing nitrogen oxides p
The general emergency measure is to suppress the temperature inside the furnace by increasing the injection amount of the injected water.

After that, in order to stabilize the temperature in the furnace, the amount of dust supplied and the feed rate of each grate are adjusted, and the amount and temperature of primary combustion air fed in are adjusted in general automatic combustion control. It is a technique.

[0009]

However, the generation position and amount of unburned gas, dioxins, and unburned oxides such as soot and carbon monoxide in the combustion chamber f fluctuate drastically depending on the quality of the waste. Despite the excessive supply of secondary combustion air, the combustion gas containing unburned gas, dioxins and unburned oxides and the secondary combustion air are not sufficiently mixed, the secondary combustion Even if you pass the area
Part of it is discharged to the gas cooling chamber h as it is unburned and undecomposed.

On the other hand, in order to reduce nitrogen oxides, it is common to use a gas on the dry grate c side, which is the main source, as a reducing atmosphere at a low temperature to self-denitrate with ammonia generated by thermal decomposition of dust. However, if the amount of secondary combustion air is increased in order to promote secondary combustion and suppress the temperature in the furnace, a high temperature oxidizing atmosphere is created and the amount of nitrogen oxide emissions increases, so the amount of secondary combustion air is limited to adjustment. There is a conflict with the stable operation of the incinerator.

Next, since the exhaust gas rising in the gas cooling chamber h is influenced by the gas flow from the combustion chamber f and goes straight toward the central portion or one side of the gas cooling chamber h, it goes straight. Not only is the entire system not being effectively used, but the amount of exhaust gas also fluctuates with fluctuations in the quality of dust. Therefore, in order to make the temperature of the exhaust gas at the inlet of the dust collector k constant, injection by the water injection nozzle i Adjust the amount of water and gas cooling chamber h
There is no choice but to adjust the temperature of the exhaust gas discharged from the exhaust gas to the dust collector k via the air preheater j.

Therefore, when a large amount of water is injected from the water injection nozzle i in response to fluctuations in the amount of exhaust gas, the non-evaporated injection water wets the side wall of the gas cooling chamber h and damages this side wall, or the air preheater j. In many cases, the tube wall was wetted to attach dust, and the non-evaporated water droplets dripped into the combustion chamber f due to mutual interference of the jet water.

Further, due to the effect of radiative cooling from the low temperature portion above the gas cooling chamber h and the above-mentioned dropping of the non-evaporated water droplets, the communication portion between the combustion chamber f and the gas cooling chamber h (the combustion gas from the combustion chamber e) There was a problem that the temperature of f1 was lowered and the secondary combustion was hindered.

On the other hand, in December 1990, the Ministry of Health and Welfare issued the "Guideline for the prevention of dioxins (draft)", which states that complete combustion in a refuse incinerator will reduce unburned oxide emissions. The index stipulates that the combustion gas be maintained at a high temperature to prevent and suppress the generation of dioxins and promote the mixing of unburned gas and secondary combustion air.

Further, in the dust collector, the gas temperature at the entrance of the dust collector is set to be lowered in order to prevent regeneration of dioxins, and it is necessary to increase the cooling capacity in the gas cooling chamber. I am under pressure.

[0016]

According to a first aspect of the present invention, there is provided a waste incineration method for a waste incinerator provided with a gas mixing device, wherein a gas cooling chamber is provided above a combustion chamber, and the combustion chamber and the gas cooling chamber are provided. A gas incinerator having a plurality of gas passages formed in the vicinity of a communicating portion with and a gas mixing device for injecting tertiary combustion air into each gas passage. , The combustion gas, which is about to flow from the combustion chamber into the gas cooling chamber, collides with the gas mixing device, stays in the combustion chamber or swirls in the combustion chamber for secondary combustion, and further flows into the gas passage of the gas mixing device. Tertiary combustion air is injected into the combustion gas to be subjected to tertiary combustion near the inlet of the gas passage, which is the outlet of the combustion chamber, and the combustion gas that has undergone the tertiary combustion is passed through the gas passage to the gas cooling chamber. To guide In case of the three primary combustion, the temperature of the gas flowing into the gas cooling chamber from the combustion chamber as a first priority, then, the CO concentration in the exhaust gas second priority, further O ₂ concentration in the exhaust gas first The third priority is to control the supply amount of the tertiary combustion air injected into the gas passage.

According to a second aspect of the present invention, there is provided a method for incinerating waste in a waste incinerator equipped with a gas mixing device, the method for incinerating waste in a waste incineration device having a gas mixing device in accordance with the first aspect, wherein a gas cooling chamber is provided. With the gas flow rate measuring device installed freely in and out, the exhaust gas flow rate distribution in the gas cooling chamber is measured and the flow rate distribution state is averaged.
The amount of tertiary combustion air injected into each gas passage is adjusted.

[0018]

In the waste incineration method according to the first aspect of the present invention, the gas mixing device is installed at the connecting portion between the combustion chamber and the gas cooling chamber provided above the combustion chamber, and the combustion gas generated by combustion in the combustion chamber is provided. Collide with the gas mixing device to reflect the amount of heat stored therein into the combustion chamber to almost complete the secondary combustion in the combustion chamber, and further inject the tertiary combustion air from the gas mixing device, The combustion gas temperature is stabilized by tertiary combustion near the inlet of the gas passage that serves as the outlet. Moreover, the temperature in the combustion chamber rises due to abnormal combustion,
When oxygen is insufficient, operation to restore the combustion chamber outlet temperature by increasing the tertiary combustion air injection amount (first priority)
Then, in order to reduce the CO concentration, which is an index of unburned substances, and re-burn the unburned oxides, which are the generation source of dioxins, an insufficient third combustion air amount correction operation (second priority) is performed. Further, in order to secure the minimum excess oxygen, the O ₂ concentration control (third priority) is performed to completely mix the high temperature exhaust gas and the tertiary combustion air to generate the gas in the gas mixing device. Complete the 3rd combustion near the entrance of the passage. According to the refuse incineration method of claim 2, the exhaust gas flow distribution state in the gas cooling chamber is measured by the gas flow rate measuring device installed so as to freely move in and out, and a plurality of gas flow sensors are formed in the gas mixing device based on this measurement. By individually controlling the amount of the tertiary combustion air injected into the gas passage, the exhaust gas flow rate distribution passing through the gas passage and swirling up in the gas cooling chamber is averaged.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a schematic structure of a refuse incinerator having a gas mixing device according to the present invention, and FIG. 2 shows an incinerator.

In the figure, 1 is a hopper, 3 is an incinerator 2
A dry grate provided therein, 4 a combustion grate provided on the discharge side of the dry grate 3, 5 a post-combustion device, 6 a supply port for secondary combustion air 14, 9 a combustion chamber, 20 Gas cooling room,
Reference numeral 21 is a water injection nozzle, 22 is an air preheater communicated with the outlet of the gas cooling chamber 20, 23 is a dust collector, 24 is an induced air blower, and 25 is a chimney.

The incinerator 2 is provided with an in-reactor water injection nozzle 10 above the dry grate 3. The in-reactor water injection nozzle 10 is connected to a water supply source (not shown) via an in-reactor water injection control valve 11.

The supply port 6 is connected to a secondary combustion air blower 13 via a secondary combustion air adjusting damper 12.

Further, the combustion chamber 9 of the incinerator 2 is provided with a reducing atmosphere temperature detector 15 and a secondary combustion zone temperature detector 16, respectively. The detection signals detected by the reducing atmosphere temperature detector 15 and the secondary combustion zone temperature detector 16 are output to a first control unit 60 (see FIG. 4) described later, and the first control unit 60 uses the detection signals based on these detection signals. The in-reactor water injection control valve 11 to control the amount of water injected from the in-reactor water injection nozzle 10 and the secondary combustion air adjusting damper 12
Is controlled to control the supply amount of the secondary combustion air 14 discharged from the supply port 6 by the secondary combustion air blower 13.

A communication portion 9a between the combustion chamber 9 and the gas cooling chamber 20
A gas mixing device 30 is provided (that is, at the outlet of the combustion chamber 9).

The gas mixing device 30, as shown in FIG.
A main body 31 made of a refractory material for reflecting the amount of heat of the combustion gas 8 in the combustion chamber 9 to block the cooling effect from the gas cooling chamber 20 and keeping the inside of the combustion chamber 9 at a high temperature;
A plurality of gas passages 32, a plurality of gas passages 32, a plurality of ventilation pipes 33, which are arranged in the main body 31 with the gas passages 32 interposed therebetween, and are connected to a tertiary combustion air blower 40 that supplies the tertiary combustion air 42, It is composed of an injection port 35 which is branched from the ventilation pipe 33 and injects the tertiary combustion air 42.

The gas passage 32 serves as a ventilation resistance when the combustion gas 8 passes, and the passed gas is used as the gas cooling chamber 20.
It is formed so as to be inclined in a predetermined direction so as to generate a gas flow such as swirling inside.

The above-mentioned tertiary combustion air blower 40 and each ventilation pipe 3
3 combustion air blowing control valve 4 in each pipe that communicates with 3
1 is installed respectively. The supply amount to be supplied to each ventilation pipe 33 is individually adjustable by these tertiary combustion air blowing control valves 41, and the injection amount of the tertiary combustion air 42 injected from the injection port 35 of each ventilation pipe 33 is configured. Can be adjusted.

Each injection port 35 is formed so as to face the combustion gas 8 passing through the gas passage 32 and inject it. The injection port 35 is connected to the communication unit 9 facing the gas mixing device 30.
It is also provided on the side wall of a and communicates with the tertiary combustion air blower 40 via a tertiary combustion air blowing control valve 41.

A gas flow rate measuring device 50 for measuring the flow rate of the exhaust gas 19 flowing in the gas cooling chamber 20 is provided in the middle of the gas cooling chamber 20.

The gas flow rate measuring device 50 is normally submerged outside the gas cooling chamber 20 and protrudes to each measurement position in the gas cooling chamber 20 indicated by the alternate long and short dash line only at a designated time. The flow distribution state of the exhaust gas 19 is measured.

A combustion chamber outlet temperature detector 51 is provided above the gas mixing device 30.

Further, a chimney inlet CO concentration detector 52 and a chimney inlet O ₂ concentration detector 5 are provided at the inlet of the chimney 25.
3 is provided.

These combustion chamber outlet temperature detector 51, chimney inlet CO concentration detector 52, and chimney inlet O ₂ concentration detector 5
The respective detection signals detected in 3 are the second control unit 70 described later.
(See FIG. 5), and the second control unit 70 controls the respective tertiary combustion air blowing control valves 41 based on these detection signals, and at the same time controls the total air flow rate of the tertiary combustion air blower 40.

Next, an explanation will be given of the case of incinerating waste by the waste incinerator equipped with the gas mixing device thus constructed.

First, the incineration of dust in the combustion chamber 9 will be briefly described.

The trash grasped by the trash crane (not shown) from the trash pit (not shown) is thrown into the hopper 1. The dust thrown into the hopper 1 is fed on the dry grate 3 and the combustion grate 4 from below each grate 3, 4.
The flame-retardant materials and unburned materials that are ignited and burned by the next combustion air (not shown) are placed on the post-combustion device 5 and burned to form incinerated ash. After extinguishing the fire and absorbing moisture, it is carried out of the site.

Further, the flame and the combustion gas 8 generated by the combustion of dust rise in the combustion chamber 9 while radiating the high-temperature energy that the combustion chamber 9 retains, and flow into the gas cooling chamber 20. Due to the ventilation resistance of 30, most of the gas cannot stay in the gas cooling chamber 20 and stay there, or some of it stays upside down and swirls in the combustion chamber 9.

As the combustion gas 8 swirls in this way,
The heat quantity of the combustion gas 8 is radiated to the front part of the combustion chamber 9 to accelerate the drying of dust, and the swirling combustion gas 8 and undecomposed dioxins existing in the combustion chamber 9
The unburned gas 7 containing odorous components and unburned oxides such as soot and carbon monoxide and the secondary combustion air 14 are mixed to form a combustion chamber 9
Secondary combustion occurs on the entire inner surface.

Then, the gas passage 32 of the gas mixing device 30.
The combustion gas 8 flowing into the combustion chamber 9 is injected with the tertiary combustion air 42 from the injection port 35 in a counter flow.
Combustion gas 8 that has undergone secondary combustion in the interior, but still contains minute dioxins and unburned oxides, and tertiary combustion air 4
2 and 2 are completely mixed, and undecomposed substances and unburned oxides are re-combusted near the inlet of the gas passage 32, which is kept at a high temperature by the radiant heat of the gas mixing device body 31.

FIG. 4 shows a block diagram of the first controller 60, and FIG. 5 shows a block diagram of the second controller 70. The first controller 60 and the second controller 70 are shown.
In addition to the above description, the waste incineration method in the waste incineration apparatus equipped with the gas mixing device of the present invention will be described.

First, as shown in FIG. 4, the temperature measured by the reducing atmosphere temperature detector 15 is input to the comparing and calculating section 61, and in the comparing and calculating section 61, the reducing atmosphere temperature setter 62 is used.
In the internal combustion water injection control valve 11, the internal combustion water injection control valve 63 controls the in-reactor water injection control valve 11 to output a correction signal to the internal combustion water injection amount control unit 63 to compare the temperature with a preset temperature. The amount of water injected from the water injection nozzle 10 is preferentially controlled, and the correction signal is sent to the secondary combustion air amount control unit 6
5, and the secondary combustion air amount control unit 65 controls the secondary combustion air adjusting damper 12 to control the supply amount of the secondary combustion air 14 to the extent that the reduction state is not destroyed.

The temperature detected by the secondary combustion zone temperature detector 16 is integrated by the comparison / delay operation circuit 66 for a unit time, and the integrated average value is preset by the secondary combustion zone temperature setter 67. When it deviates from the temperature range, the correction signal is output to the comparison calculation unit 61. The comparison calculation unit 61 outputs a command signal to the secondary combustion air amount control unit 65 based on the correction signal, and the secondary combustion air amount control unit 65 controls the secondary combustion air adjustment damper 12 to destroy the reduction state. The supply amount of the secondary combustion air 14 is preferentially controlled to the extent that it does not exist, and the correction shortage is corrected by the injection water amount control unit 63 in the combustion chamber.
The in-reactor water injection control valve 11 is controlled to control the amount of water injected from the in-reactor water injection nozzle 10.

By this series of operations, most of the thermal decomposition of odorous components and recombustion of unburned oxides are completed, and
The main generation area of nitrogen oxides can be maintained in a reducing atmosphere at a relatively low temperature, so that oxidation of dust or nitrogen in the air can be suppressed.

However, according to the above-mentioned method, when the temperature in the reduction zone and the secondary combustion zone rises, not only the temperature in the combustion chamber 9 cannot be controlled, but also the thermal decomposition of dioxins does not proceed and the combustion gas 8 Some unburned oxides such as soot and carbon monoxide will remain inside.

These are the second control section 7 shown in FIG.
Controlled by 0.

The temperature of the exhaust gas 19 detected by the combustion chamber outlet temperature detector 51 is input to the comparison / delay circuit 71, integrated by the comparison / delay circuit 71 for a unit time, and the integrated average value thereof is set in the combustion chamber outlet temperature setter. If the temperature range deviates from the preset temperature range by 72, a correction signal is output to the tertiary combustion air total amount calculation unit 73. The tertiary combustion air total amount calculation unit 73 calculates the required air volume based on the correction signal, and the tertiary combustion air total amount control unit 74 controls the tertiary combustion air blower 40 to control the tertiary combustion air 42 (that is, the furnace temperature cooling). The amount of air supplied is controlled to restore the combustion chamber outlet temperature.

That is, the three-stage combustion system is implemented in the reducing atmosphere sphere, the secondary combustion sphere, and the peripheral portion of the gas mixing device 30, and the combustion chamber outlet temperature control is performed by the conventional secondary combustion. Most of the new methods are adopted, in which control is changed from air to control by tertiary combustion air.

On the other hand, the oxygen monoxide concentration measured by the chimney inlet CO concentration detector 52 is input to the CO concentration integrator 75, and the CO concentration integrator 75 integrates it for a certain period of time, and the integrated average value is used as the CO concentration comparator 76. Output to. The CO concentration comparator 76 compares the input integrated average value with the preset value set by the CO average concentration setter 77, and if the integrated average value differs from the set value, the tertiary combustion air total amount calculation unit 73 corrects it. A signal is output, and the third combustion air total amount control unit 74 outputs 3
The secondary combustion air blower 40 is controlled to control the supply amount of the tertiary combustion air 42. As a result, the combustion gas 8 in the combustion chamber 9 and the tertiary combustion air 42 can be sufficiently mixed to burn the combustion gas 8 completely, and the carbon monoxide emission amount can be reduced.

Here, the carbon monoxide concentration measured by the CO concentration detector 52 at the chimney inlet is an alternative means for grasping the emission amount of dioxins which cannot be continuously measured at present, and the carbon monoxide emission amount. That is, the amount of dioxins emitted is reduced.

Further, whether or not the complete combustion has been carried out remains.
It can be judged by measuring the oxygen concentration. Therefore, the chimney
Entrance O₂Residual oxygen concentration measured by the concentration detector 53
Is O ₂It is input to the concentration integrator 78 and O₂Concentration integrator 78
For a certain period of time, and the integrated average value is O₂Concentration comparator 7
Output to 9. O₂In the density comparator 79, the input integration
Average value and O₂Dust collector 23, etc. with the average concentration setting device 80
The preset value by correcting the amount of leaked air in the middle of
And when the integrated average value is different from the set value, the third combustion
The correction signal is output to the total air amount calculation unit 73, and the tertiary combustion air is output.
Control the tertiary combustion air blower 40 by the total amount control unit 74
Then, the supply amount of the tertiary combustion air 42 is controlled.

Although there are three command signals input to the above-described tertiary combustion air total amount calculation unit 73, the combustion chamber outlet temperature correction has the first priority, the chimney inlet CO concentration correction has the second priority, and the chimney inlet O ₂ The density correction is controlled with the third priority.

On the other hand, in order to equalize the distribution state of the exhaust gas 19 in the gas cooling chamber 20, the comparison / delay circuit 71 is provided.
Then, when the correction signal is output to the tertiary combustion air total amount calculation unit 73, the command signal is also output to the gas flow rate measurement device control unit 81. In the gas flow rate measurement device control unit 81, the gas flow rate measurement device 50 is inserted into the gas cooling chamber 20 based on the command signal to measure the distribution state of the exhaust gas 19, and the tertiary combustion air amount distribution calculation is performed based on this measurement result. The part 82 controls each tertiary combustion air blowing control valve 41, and controls the injection amount of the tertiary combustion air 42 for each ventilation pipe 33. Exhaust gas 19
By equalizing the distribution state of (3), the residence time of the exhaust gas 19 in the gas cooling chamber 20 can be lengthened and the cooling efficiency can be improved.

The detection position of the CO concentration detector 52 at the chimney inlet may be the inlet or the outlet of the dust collector 23 or the outlet of the chimney 25. Further, the detection position of the chimney inlet O ₂ concentration detector 53 may be the outlet of the combustion chamber 9, the inlet or outlet of the dust collector 23, or the outlet of the chimney 25.

[0055]

As described above, according to the waste incineration method of the first aspect of the present invention, the gas mixing device is installed at the connecting portion between the combustion chamber and the gas cooling chamber installed above the combustion chamber, The combustion gas generated by the combustion in the combustion chamber is made to collide with the gas mixing device to reflect the amount of heat stored therein to the combustion chamber, so that the secondary combustion is almost completed in the combustion chamber. By injecting combustion air and performing tertiary combustion in the vicinity of the inlet of the gas passage that serves as the outlet of the combustion chamber, it is possible to stabilize the temperature of the combustion gas and perform control for complete combustion. Moreover, if the temperature in the combustion chamber rises due to abnormal combustion and the oxygen is in a deficient state, an operation (first priority) is performed to increase the tertiary combustion air injection amount to restore the combustion chamber outlet temperature, and then C which is an index of fuel
In order to reduce the O concentration and re-burn the unburned oxides that are the source of dioxins, perform a deficient tertiary combustion air amount correction operation (second priority), and secure a minimum excess oxygen. Therefore, by performing the O ₂ concentration control (third priority), the high-temperature exhaust gas and the tertiary combustion air are completely mixed, and the tertiary combustion can be completed in the gas passage in the gas mixing device. For this reason, thorough pollution control can be reasonably carried out without specially installing a reburning chamber or a secondary incinerator.

According to the waste incineration method of the second aspect, the exhaust gas flow distribution state in the gas cooling chamber is measured by the gas flow rate measuring device installed freely in and out, and formed in the gas mixing device based on this measurement. By individually controlling the amount of the tertiary combustion air injected into the plurality of gas passages, the exhaust gas flow rate distribution that swirls and rises in the gas cooling chamber through the gas passages can be averaged. The volume of the chamber can be effectively used.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an overall outline of a refuse incinerator provided with a gas mixing device according to the present invention.

FIG. 2 is a vertical side view showing an incinerator.

FIG. 3 is a cross-sectional view showing a gas mixing device.

FIG. 4 is a block diagram showing a configuration of a first control unit.

FIG. 5 is a block diagram showing a configuration of a second control unit.

FIG. 6 is a configuration diagram showing a conventional refuse incinerator.

[Explanation of Codes] 9 Combustion chamber 9a Communication part 20 Gas cooling chamber 30 Gas mixing device 32 Gas passage 40 Third combustion air blower 42 Third combustion air

Claims (2)

[Claims] 1. A gas cooling chamber is provided in the upper part of the combustion chamber, and a gas mixing device is provided in which a plurality of gas passages are formed in the vicinity of a communicating portion between the combustion chamber and the gas cooling chamber. A refuse incinerator equipped with a gas mixing device for injecting combustion air, wherein the combustion gas that is about to flow into the gas cooling chamber from the combustion chamber collides with the gas mixing device when incinerating the dust, and stays in the combustion chamber. Alternatively, the secondary combustion is performed by swirling in the combustion chamber, and the tertiary combustion air is injected into the combustion gas which is about to flow into the gas passage of the gas mixing device, and the vicinity of the inlet of the gas passage serving as the outlet of the combustion chamber. In the third combustion, the combustion gas that has been third-combusted is guided to the gas cooling chamber through the gas passage, and at the time of the third combustion, the temperature of the gas flowing from the combustion chamber into the gas cooling chamber is set to the first temperature. Prioritize, then , Give priority to CO concentration in exhaust gas,
Furthermore, the waste incineration method in a waste incinerator equipped with a gas mixing device, characterized in that the supply amount of the tertiary combustion air injected into the gas passage is controlled by giving the O ₂ concentration in the exhaust gas the third priority. 2. A waste incineration method in a waste incinerator equipped with the gas mixing device according to claim 1, wherein the exhaust gas flow rate distribution in the gas cooling chamber is measured by a gas flow rate measuring device that is installed in and out of the gas cooling chamber. However, the amount of tertiary combustion air injected into each of the gas passages is adjusted so that the flow distribution state is averaged. .