JP6965842B2 - Waste incinerator and waste incinerator method - Google Patents

Description

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

The incineration ash generated when waste such as municipal waste and industrial waste is incinerated in an incinerator is discharged from the incinerator, put into an ash cooling tank, extinguished and cooled by the cooling water in the tank, and then extinguished from the ash cooling tank. It has been carried out and disposed of in landfill.

In the ash cooling tank that receives the incineration ash discharged from the incinerator and cools the incineration ash with cooling water, particulate matter called scum generated from the components dissolved or separated from the incinerator ash floats and accumulates on the water surface of the cooling water. do. Scum may be deposited with a thickness of several tens of centimeters, which may hinder the removal of incinerated ash after cooling from the ash cooling tank. It is removed by.

Patent Document 1 and Patent Document 2 disclose an ash extrusion device having an extrusion member for extruding and discharging incinerator ash settled in an ash cooling tank, and the incinerator ash is extruded by pushing the incinerator ash out of the tank with the extrusion member. It is stated that scum can be prevented from flowing into areas where the operation of the member may be hindered.

JP-A-2002-340323 JP 2006-317110

In order to remove the scum, in order to perform watering spray and aeration to remove the scum, it is necessary to install equipment for that purpose and its operating cost, and the burden on the operator is large due to the manual scum removal. There is a problem that the operating cost is high.

In addition, when the incinerator ash is carried out from the ash cooling tank, a scum adheres to the carry-out conveyor, which makes the conveyor inoperable, and the water level sensor for measuring the water level of the ash cooling tank is buried in the scum. There is a problem that the operation of the ash cooling tank is hindered, such as being unable to measure.

Under such circumstances, in Patent Documents 1 and 2, by using the described extrusion member, it is possible to prevent the scum from flowing into the region that interferes with the operation of the extrusion member, but the scum generation itself Cannot be suppressed.

In view of such circumstances, the present invention provides a waste incinerator and a waste incineration method for keeping the incinerator ash generated in the incinerator in a state in which scum is unlikely to occur when the incinerator ash is brought into the ash cooling tank. The challenge is to provide.

According to the present invention, the above-mentioned problems are solved by a waste incinerator having the following configuration and a waste incinerator method using the same.

[Waste incinerator]
The waste incinerator of the present invention is configured as in the following first invention or second invention.

<First invention>
Waste incinerator equipped with an incinerator having a dry grate, a combustion grate and a post-combustion grate to incinerate waste, and an ash cooling tank for storing cooling water and receiving and cooling incinerator ash discharged from the incinerator. In the device
Primary air supply means that supplies primary air below the dry grate and combustion grate, circulating exhaust gas supply means that supplies part of the exhaust gas from the incinerator below the post-combustion grate, and cooling water in the ash cooling tank. Circulating exhaust gas supply amount adjusting means for adjusting the amount of circulating exhaust gas supplied below the incinerator grate based on the cooling water temperature measuring means for measuring the temperature and the cooling water temperature measured value measured by the cooling water temperature measuring means. A waste incinerator characterized by having and.
In the first invention, the circulating exhaust gas supply amount adjusting means preferably adjusts the circulating exhaust gas supply amount so that the cooling water temperature of the ash cooling tank is 65 ° C. or lower.
Further, in the first invention, it is preferable that the circulating exhaust gas supply amount adjusting means adjusts the circulating exhaust gas supply amount to ^{5 to 20 m 3 per 1 kg of incineration ash discharge amount.}
Further, in the first invention, the circulating exhaust gas supply quantity adjusting means preferably adjusts the circulation flue gas supply amount to the waste incineration weight 1kg per circulation exhaust gas supply quantity 500~2000m ^3.

<Second invention>
Waste incinerator equipped with an incinerator having a dry grate, a combustion grate and a post-combustion grate to incinerate waste, and an ash cooling tank for storing cooling water and receiving and cooling incinerator ash discharged from the incinerator. In the device
A primary air supply means that supplies primary air below the dry grate, combustion grate, and post-combustion grate, a circulating exhaust gas supply means that supplies part of the incinerator exhaust gas below the post-combustion grate, and ash. Circulation that adjusts the amount of circulating exhaust gas supplied below the post-combustion grate based on the cooling water temperature measuring means that measures the cooling water temperature of the cooling tank and the cooling water temperature measurement value that is measured by the cooling water temperature measuring means. Having a primary air / circulating exhaust gas supply control means for post-combustion that controls the exhaust gas supply amount adjusting means and the primary air supply amount adjusting means for adjusting the primary air supply amount to be supplied below the post-combustion grate. A waste incineration device characterized by.
In the second invention, the primary air / circulating exhaust gas supply amount controlling means for the post-combustion gas preferably controls the circulating exhaust gas supply amount so that the cooling water temperature of the ash cooling tank is 65 ° C. or lower.

[Waste incinerator method]
The waste incinerator method of the present invention is configured as in the following third or fourth invention.

<Third invention>
In a waste incineration method in which waste is incinerated in an incinerator having a dry grate, a combustion grate, and a post-combustion grate, and the incineration ash discharged from the incinerator is cooled in an ash cooling tank.
The primary air is supplied from the primary air supply means below the dry grate and the combustion grate, and a part of the incinerator exhaust gas is supplied from the circulating exhaust gas supply means below the post-combustion grate. The cooling water temperature of the ash cooling tank is measured, and the circulating exhaust gas supply amount supplied below the post-combustion grate is adjusted by the circulating exhaust gas supply amount adjusting means based on the cooling water temperature measurement value measured by the cooling water temperature measuring means. A waste incinerator method characterized by doing so.
In the third invention, it is preferable to adjust the circulating exhaust gas supply amount by the circulating exhaust gas supply amount adjusting means so that the cooling water temperature of the ash cooling tank is 65 ° C. or lower.
In the third invention, it is preferable to adjust the ^{circulating exhaust gas supply amount to 5 to 20 m 3} per 1 kg of incineration ash discharge by the circulating exhaust gas supply amount adjusting means.
Further, in the third invention, the circulating exhaust gas supply amount adjusting means, it is preferable to adjust the circulation flue gas supply amount to the waste incineration weight 1kg per circulation exhaust gas supply quantity 500~2000m ^3.

<Fourth invention>
In a waste incineration method in which waste is incinerated in an incinerator having a dry grate, a combustion grate, and a post-combustion grate, and the incineration ash discharged from the incinerator is cooled in an ash cooling tank.
Primary air is supplied below the dry grate, combustion grate, and post-combustion grate from the primary air supply means, and part of the exhaust gas from the incinerator is supplied below the post-combustion grate from the circulating exhaust gas supply means for cooling. The cooling water temperature of the ash cooling tank is measured by the water temperature measuring means, and the circulating exhaust gas supply amount by the primary air / circulating exhaust gas supply amount control means for post-combustion based on the cooling water temperature measurement value measured by the cooling water temperature measuring means. It is characterized in that the adjustment of the circulating exhaust gas supply amount supplied below the post-combustion grate by the adjusting means and the adjustment of the primary air supply amount supplied below the post-combustion grate by the primary air supply amount adjusting means are controlled. Waste incineration method.
In the fourth invention, it is preferable to adjust the circulating exhaust gas supply amount so that the cooling water temperature of the ash cooling tank is 65 ° C. or lower by the primary air / circulating exhaust gas supply amount controlling means for post-combustion.

[Principle of invention]
<Root cause analysis of scum occurrence>
(I) High-temperature incinerator ash is put into the ash cooling tank from the incinerator, and small particle particles, etc. generated by the reaction from the incinerator or contained in the incinerator are suspended and accumulated on the surface of the cooling water to form a scum. Become. Most of the scum is calcium hydroxide particles generated in cooling water from calcium oxide contained in incineration ash, and aluminate-based cement hydrate particles generated by reaction from incineration ash components in cooling water, and calcium hydroxide particles. Partially dissolves in cooling water, but insoluble matter floats, and aluminate-based cement hydrate particles do not dissolve in water and float, and both become scum.

(Ii) In the grate-type waste incinerator, after the waste is burned in the combustion grate, the unburned portion is post-combusted in the post-combustion grate. The unburned part is completely burned by ventilating a small amount of air. Since the cooling action by air blowing from below the post-combustion grate is small, the incinerated ash on the post-combustion grate is kept at a high temperature. In addition, the calcium contained in the waste exists in the form of calcium oxide in the incinerated ash due to combustion at a high temperature, and the incinerated ash is discharged to the ash cooling tank, and the calcium oxide and water of the incinerated ash are discharged in the ash cooling tank. Calcium hydroxide produced by the reaction with is present, so that the pH of the cooling water in the ash cooling tank is kept high.

(Iii) When incineration ash containing a large amount of calcium oxide is added to the high pH cooling water of the ash cooling tank, most of the calcium hydroxide particles generated by the reaction between calcium oxide in the incineration ash and water become water. It does not dissolve, and a large amount of insoluble calcium hydroxide particles are generated and float to scum.

<Suppression of scum generation>
Therefore, a part of the exhaust gas from the incinerator (called circulating exhaust gas) is supplied from below the post-combustion grate of the grate-type waste incinerator, and the incineration ash on the post-combustion grate is unlikely to generate scum. To. When a part of the exhaust gas is supplied from below the post-combustion grate, the incineration ash on the post-combustion grate becomes less likely to generate scum for the following reasons.

(1) By blowing the circulating exhaust gas from below the post-combustion grate, calcium oxide in the incineration ash is carbonated by the reaction with carbon dioxide contained in the circulating exhaust gas to obtain calcium carbonate. In this way, the calcium oxide content in the incinerated ash is reduced, the amount of calcium hydroxide particles generated by reacting with water in the ash cooling tank is reduced, and the presence of calcium hydroxide particles as insoluble matter is suppressed. , Suppresses the generation of scum.

(2) The higher the temperature of the cooling water in the ash cooling tank, the smaller the solubility of the calcium hydroxide particles, the larger the amount of calcium hydroxide insoluble matter present, and the more likely scum is to occur. Therefore, by blowing circulating exhaust gas from below the post-combustion grate instead of the conventional air, the amount of air blown to the post-combustion grate is increased and the temperature of the incineration ash is lowered as compared with the case where air is blown. , The temperature of the cooling water in the ash cooling tank is lowered, the solubility of calcium hydroxide in the cooling water is increased, and the amount of calcium hydroxide present as an insoluble component is reduced to suppress the generation of scum.

(3) The reaction rate for the formation of aluminate-based cement hydrate is highly temperature-dependent, and the higher the temperature of the cooling water in the ash cooling tank, the higher the reaction rate for the formation of aluminate-based cement hydrate, resulting in scum. It will be easier. Therefore, by blowing circulating exhaust gas from below the post-combustion grate instead of the conventional air, the amount of air blown to the post-combustion grate is increased and the temperature of the incinerated ash is lowered as compared with the case where air is blown. The temperature of the cooling water in the ash cooling tank is lowered, the reaction rate of the formation of aluminate-based cement hydrate is lowered, the amount of formation is reduced, and the generation of scum is suppressed.

In this way, by blowing the circulating exhaust gas from below the post-combustion grate instead of the conventional air, the amount of air blown to the post-combustion grate is increased and the temperature of the incineration ash is lowered as compared with the case where air is blown. By lowering the temperature of the cooling water in the ash cooling tank, the abundance of insoluble calcium hydroxide is reduced, and the amount of aluminate-based cement hydrate produced is reduced to suppress scum generation. be able to. Preferably, by setting the temperature of the cooling water in the ash cooling tank to 65 ° C. or lower, it is highly effective in increasing the solubility of calcium hydroxide and reducing the reaction rate of the formation of aluminate-based cement hydrate. I found that.

As described above, the present invention supplies the primary air from the primary air supply means below the dry grate and the combustion grate, or below the dry grate, the combustion grate and the post-combustion grate, and supplies the circulating exhaust gas. A part of the exhaust gas from the incinerator is supplied from the means to the lower part of the post-combustion grate, the cooling water temperature of the ash cooling tank is measured by the cooling water temperature measuring means, and the cooling water temperature measured by the cooling water temperature measuring means. Based on the measured values, the circulating exhaust gas supply amount supplied below the post-combustion grate is adjusted by the circulating exhaust gas supply adjusting means, or the circulating exhaust gas supply amount is adjusted by the primary air / circulating exhaust gas supply controlling means for post-combustion. Since it was decided to control the adjustment of the circulating exhaust gas supply amount supplied to the lower part of the post-combustion grate by means and the adjustment of the primary air supply amount to be supplied to the lower part of the post-combustion grate by the primary air supply amount adjusting means. By supplying the circulating exhaust gas to the incineration ash on the combustion grate, the calcium oxide in the incineration ash that causes scum is carbonated by the carbon dioxide contained in the circulating exhaust gas to reduce the calcium oxide, and the circulating exhaust gas is blown in. As a result, the temperature of the incinerated ash is lowered, the temperature of the cooling water in the ash cooling tank is lowered, the solubility of calcium hydroxide in the cooling water is increased, and the undissolved content of calcium hydroxide is reduced. The formation reaction rate of cement hydrate is reduced, the formation of aluminate-based cement hydrate is suppressed, and the generation of scum in the ash cooling tank can be suppressed. Therefore, the conventionally used equipment such as watering spray and aeration is not required, and the operating cost for operating the equipment and the scum removal work cost by the operator can be reduced. In addition, problems such as the conveyor that carries out the incinerator ash from the cooling tank becoming inoperable and the water level sensor becoming inoperable do not occur.

It is a schematic block diagram of the waste incinerator which concerns on 1st Embodiment of this invention. It is a schematic block diagram of the waste incinerator which concerns on 2nd Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

<First Embodiment>
FIG. 1 shows the overall configuration of the waste incinerator according to the first embodiment of the present invention, and the waste incinerator 1 is an incinerator 1 for incinerating waste and discharged from the incinerator 1. A boiler 10 that recovers heat by exchanging heat with exhaust gas to generate steam, a bug filter 11 that removes the exhaust gas that has been heat-recovered by the boiler 10, and an exhaust gas that has been dust-removed by the bug filter 11 are released into the atmosphere. A chimney 12 for this purpose and an ash cooling tank 20 for cooling the incinerated ash discharged from the incinerator 1 are provided.

The incinerator 1 is arranged above a combustion chamber 2 for burning waste such as industrial waste and household waste, and an upstream side (left side in FIG. 1) of the combustion chamber 2 in the waste flow direction. , A waste inlet 3 for charging waste into the combustion chamber 2 and a secondary combustion chamber 4 connected above the downstream side (right side in FIG. 1) of the combustion chamber 2 in the waste flow direction. It is a grate-type incinerator equipped with. In the secondary combustion chamber 4 connected to the combustion chamber 2, the unburned component (unburned gas) of the combustible gas generated in the combustion chamber 2 is burned (secondary combustion).

At the bottom of the combustion chamber 2, a grate (stalker) 5 for burning waste while moving it is provided. The grate 5 is a dry grate 5a forming a dry region, a combustion grate 5b forming a combustion region, and a post-combustion fire forming a post-combustion region from the side closer to the waste input port 3, that is, from the upstream side. The grids 5c are provided in this order, and a waste layer is formed mainly on the dry grate 5a and the combustion grate 5b, and an incineration ash layer is formed in the downstream portion of the post-combustion grate.

In the dry grate 5a, waste is mainly dried and ignited. In the combustion grate 5b, the waste is mainly thermally decomposed and partially oxidized, and the combustible gas generated by the thermal decomposition and the solid content are burned to form a flame when the combustible gas burns. On the post-combustion grate 5c, the unburned solids in the unburned waste are completely burned, and when the solids in the waste burn, no flame is generated. Burn. As a result, a layer of incinerated ash after complete combustion is formed on the downstream side portion (right half portion in FIG. 1) of the post-combustion grate 5c. The incinerator ash is dropped and discharged from the incinerator ash discharge unit 6 to the ash cooling tank 20.

In the present embodiment, a primary air supply line 8 is provided as a primary air supply means for supplying primary air for combustion from below the dry grate 5a and the combustion grate 5b. The primary air supply line 8 includes a blower 7, and has branch lines 8a and 8b connected below the dry grate 5a and below the combustion grate 5b on the downstream side of the blower 7. The primary air is fed from below the dry grate 5a and below the combustion grate 5b, respectively.

The primary air for combustion is used for drying and burning the waste on the dry grate 5a and the combustion grate 5b, and also has a cooling action on the dry grate 5a and the combustion grate 5b and a stirring action on the waste.

The circulating exhaust gas supply line 13 that sends a part of the exhaust gas after dust removal by the bag filter 11 to the lower part of the post-combustion grate 5c from the exhaust gas duct (flue) on the outlet side of the bag filter 11 is the circulating exhaust gas. It is provided as a supply means. The circulating exhaust gas supply line 13 is provided with a damper or a valve 14 as a means for adjusting the circulating exhaust gas supply amount for adjusting the flow rate. A blower 15 is also provided in the circulating exhaust gas supply line 13.

The ash cooling tank 20 includes an incineration ash cooling unit 21 that stores cooling water WA, an incineration ash receiving unit 22 that extends upward from the incineration ash cooling unit 21 and opens upward, and the incineration ash cooling unit 21. It has a cooling ash discharge unit 23 that opens downward at the upper left and discharges the incineration ash as cooling ash after cooling, and the inside of the incineration ash cooling unit 21 is a cooling that measures the temperature of the cooling water WA. A cooling water thermometer 24 as a water temperature measuring means is provided. The opening of the incineration ash receiving portion 22 is located below the incineration ash discharging portion 6 of the incinerator 1. Further, in the incinerator ash cooling unit 21, the bottom of the tank facing the cooling ash discharging unit 23 has an inclined surface, and the cooling ash is conveyed toward the cooling ash discharging unit 23 along the inclined surface. (Not shown) is provided.

Such a waste incinerator device of the present embodiment is operated as follows.

In the embodiment of FIG. 1, first, when the waste W is charged into the waste input port 3, the waste W is supplied to the drying grate 5a and dried by the operation of each grate 5a, 5b, 5c. It moves from the grate 5a onto the combustion grate 5b and onto the post-combustion grate 5c, forming a waste layer on each grate 5a, 5b, 5c.

The dry grate 5a and the combustion grate 5b are supplied with primary air as combustion gas, respectively, whereby the waste on the dry grate 5a and the combustion grate 5b is dried and then burned. In the post-combustion grate 5c, a part of the incinerator 1 exhaust gas is received as circulating exhaust gas from the circulating exhaust gas supply line 13, the waste is post-combusted, and the incinerated ash falls from the incinerator ash discharge unit 6 to the ash cooling tank 20. It is discharged.

The unburned gas generated in the combustion chamber 2 is guided to the secondary combustion chamber 4, where it is mixed and stirred with the secondary air for secondary combustion, and the exhaust gas after combustion from the secondary combustion chamber 4 is a waste heat boiler. Heat is recovered at 10. After the heat is recovered, the exhaust gas discharged from the waste heat boiler 10 is sent to the bag filter 11 to remove dust. The exhaust gas after being detoxified by the bag filter 11 is discharged from the chimney 12 into the atmosphere.

In the present embodiment, the incinerated ash on the post-combustion grate 5c receives the circulating exhaust gas from below, and in a state where the temperature is lowered to some extent, it falls from the incinerator ash discharge unit 6 and incinerates the ash cooling tank 20. It is deposited in the cooling water and cooled by the incinerator ash cooling unit 21 via the ash receiving unit 22. The cooling ash is discharged from the cooling ash discharge unit 23 to the outside of the tank by a conveyor.

In the present embodiment, the temperature of the cooling water in the incineration ash cooling unit 21 is measured by the cooling water thermometer 24, and even if the cooling water rises after the incineration ash falls and accumulates in the cooling water, the measured cooling water temperature value. Is set to fall into the incineration ash cooling unit 21 after being cooled by the circulating exhaust gas to the incineration ash on the post-combustion grate 5c so that the temperature falls within an appropriate range. The supply amount of the circulating gas lowers the temperature of the incinerator ash on the post-combustion grate 5c so as to suppress the generation of scum even if the incinerator ash falls to the incinerator ash cooling unit 21 and accumulates in the cooling water. Sufficient amount. In the present embodiment, since the temperature of the incineration ash is not directly measured, the temperature of the cooling water is measured and the temperature of the incineration ash is set to a state in which scum is unlikely to occur by using the cooling water temperature as an index. The amount of circulating exhaust gas supplied to the incineration ash on the post-combustion grate 5c is adjusted so that the temperature is adjusted. The temperature of the cooling water in the incineration ash cooling unit 21 is measured by the cooling water thermometer 24 as the cooling water temperature measuring means, and the circulating exhaust gas supply amount adjusting means so as to keep the measured cooling water temperature within a predetermined temperature range. The circulating exhaust gas supply amount is adjusted by the damper or the valve 14. The principle that can make incinerator ash less prone to scum is as follows.

(1) By blowing the circulating exhaust gas from below the post-combustion grate, calcium oxide in the incineration ash is carbonated by the reaction with carbon dioxide contained in the circulating exhaust gas to obtain calcium carbonate. In this way, the calcium oxide content in the incinerated ash is reduced, the amount of calcium hydroxide particles generated by reacting with water in the ash cooling tank is reduced, and the presence of calcium hydroxide particles as insoluble matter is suppressed. , Suppresses the generation of scum.

(2) The higher the temperature of the cooling water in the ash cooling tank, the smaller the solubility of the calcium hydroxide particles, the larger the amount of calcium hydroxide insoluble matter present, and the more likely scum is to occur. Therefore, by blowing circulating exhaust gas from below the post-combustion grate instead of the conventional air, the amount of air blown to the post-combustion grate is increased and the temperature of the incineration ash is lowered as compared with the case where air is blown. , The temperature of the cooling water in the ash cooling tank is lowered, the solubility of calcium hydroxide in the cooling water is increased, and the amount of calcium hydroxide present as an insoluble component is reduced to suppress the generation of scum.

(3) The formation reaction rate of aluminate-based cement hydrate is highly temperature-dependent, and the higher the temperature of the cooling water in the ash cooling tank, the higher the formation reaction rate of aluminate-based cement hydrate, causing generation. It will be easier. Therefore, by blowing circulating exhaust gas from below the post-combustion grate instead of the conventional air, the amount of air blown to the post-combustion grate is increased and the temperature of the incinerated ash is lowered as compared with the case where air is blown. The temperature of the cooling water in the ash cooling tank is lowered, the reaction rate of the formation of aluminate-based cement hydrate is lowered, the amount of formation is reduced, and the generation of scum is suppressed.

In the present embodiment, the temperature of the cooling water in the ash cooling tank is preferably 65 ° C. or lower, and at this temperature, the solubility of calcium hydroxide is increased and the reaction rate for forming the aluminate-based cement hydrate is increased. It is effective in lowering it. Further, in order to reduce the temperature of the cooling water to 65 ° C. or lower, the amount of circulating gas supplied to the post-combustion grate 5c ^{should be adjusted to 5} to 20 m 3 per 1 kg of incineration ash emission, or the amount of waste incineration 1 kg. It is preferable to adjust the amount of circulating exhaust gas supplied to 500 ^{to 2000 m 3.} If the amount of circulating gas supplied is less than the lower limit, the effect of lowering the cooling water temperature is not sufficient, and if it is more than the upper limit, the temperature in the combustion chamber is lowered and problems occur in stable combustion of waste, which is unsuitable.

Here, the incineration ash emission amount or the waste incineration amount may be a set amount set based on the operation plan of the waste incinerator, or the actual emission amount or the incineration amount is measured by each measuring means. It may be, or it may be the calculated amount calculated from the operation data for calculating the incinerator ash emission amount or the waste incinerator amount.

Further, according to the present embodiment, by blowing the circulating exhaust gas into the incineration ash on the post-combustion grate, the detoxification treatment of heavy metals such as lead contained in the incineration ash is also performed. The detoxification treatment is performed by suppressing the elution of lead from the incinerator ash by reacting carbon dioxide contained in the circulating exhaust gas with lead contained in the incinerator ash to form carbonic acid and making it sparingly soluble. .. At that time, carbon dioxide contained in the circulating exhaust gas reacts with calcium oxide contained in the incinerator ash to form calcium carbonate, so that the pH of the incinerator ash is lowered and the lead is poorly soluble in the incinerator region. Therefore, the elution of lead from the incinerator ash is further suppressed.

<Second embodiment>
Next, a second embodiment of the present invention will be described with reference to FIG.

In the second embodiment, as compared with the first embodiment described with reference to FIG. 1, the branch line 8c is branched from the primary air supply line 8 and also supplies the primary air from below the post-combustion grate type 5c. The branch line 8c is provided with a damper or a valve 9c as a primary air supply amount adjusting means for adjusting the supply amount of the primary air to the post-combustion lower grate 5c, and the valve 9c and the circulating exhaust gas. It is characterized in that a primary air / circulating exhaust gas supply amount control device 16 for post-combustion that controls a damper or a valve 14 as a circulating exhaust gas supply amount adjusting means provided in the supply line 13 is provided, and other than these two points. Is the same as in the first embodiment. Therefore, in FIG. 2 showing the second embodiment, the same reference numerals as those in FIG. 1 showing the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

In the second embodiment, in addition to the circulating exhaust gas, primary air is also supplied from below the post-combustion grate 5c, and the post-combustion primary air / circulating exhaust gas supply amount control device 16 is based on the measured cooling water temperature. The circulating exhaust gas supply amount is adjusted by the damper or valve 14 as the circulating exhaust gas supply amount adjusting means so that the measured temperature of the cooling water is within the predetermined temperature range, and the damper or valve 9c as the primary air supply amount adjusting means is adjusted. Adjust the amount of primary air supply. By measuring the temperature of the cooling water and adjusting the circulating exhaust gas supply amount and the primary air supply amount so that the cooling water temperature is within the predetermined temperature range, the temperature of the incineration ash is set to a temperature at which scum is unlikely to occur. , Make the incinerated ash in a state where scum is unlikely to occur.

1 Incinerator 5a Dry grate 5b Combustion grate 5c Post-combustion grate 8 Primary air supply means (primary air supply line)
13 Circulated exhaust gas supply means (circulated exhaust gas supply line)
14 Circulating exhaust gas supply amount adjusting means (valve)
16 Primary air / circulating exhaust gas supply control device for post-combustion 24 Cooling water temperature measuring means (cooling water thermometer)
WA cooling water

Claims (12)

Waste incinerator equipped with an incinerator having a dry grate, a combustion grate and a post-combustion grate to incinerate waste, and an ash cooling tank for storing cooling water and receiving and cooling incinerator ash discharged from the incinerator. In the device
Primary air supply means that supplies primary air below the dry grate and combustion grate, circulating exhaust gas supply means that supplies part of the exhaust gas from the incinerator below the post-combustion grate, and cooling water in the ash cooling tank. Circulating exhaust gas supply amount adjusting means for adjusting the amount of circulating exhaust gas supplied below the incinerator grate based on the cooling water temperature measuring means for measuring the temperature and the cooling water temperature measured value measured by the cooling water temperature measuring means. A waste incinerator characterized by having and. The waste incinerator according to claim 1, wherein the circulating exhaust gas supply amount adjusting means adjusts the circulating exhaust gas supply amount so that the cooling water temperature of the ash cooling tank is 65 ° C. or lower. The waste incinerator according to claim 1 or 2, wherein the circulating exhaust gas supply amount adjusting means adjusts the circulating exhaust gas supply amount to ^{5 to 20 m 3 per 1 kg of incineration ash discharge amount.} The waste incinerator according to claim 1 or 2, wherein the circulating exhaust gas supply amount adjusting means adjusts the circulating exhaust gas supply amount to 500 ^{to 2000 m 3 per 1 kg of waste incineration amount.} Waste incinerator equipped with an incinerator having a dry grate, a combustion grate and a post-combustion grate to incinerate waste, and an ash cooling tank for storing cooling water and receiving and cooling incinerator ash discharged from the incinerator. In the device
A primary air supply means that supplies primary air below the dry grate, combustion grate, and post-combustion grate, a circulating exhaust gas supply means that supplies part of the incinerator exhaust gas below the post-combustion grate, and ash. Circulation that adjusts the amount of circulating exhaust gas supplied below the post-combustion grate based on the cooling water temperature measuring means that measures the cooling water temperature of the cooling tank and the cooling water temperature measurement value that is measured by the cooling water temperature measuring means. Having a primary air / circulating exhaust gas supply control means for post-combustion that controls the exhaust gas supply amount adjusting means and the primary air supply amount adjusting means for adjusting the primary air supply amount to be supplied below the post-combustion grate. A waste incineration device characterized by. The request for controlling the circulating exhaust gas supply amount adjusting means and the primary air supply amount adjusting means so that the cooling water temperature of the ash cooling tank is 65 ° C. or lower as the primary air / circulating exhaust gas supply amount controlling means for post-combustion. Item 5. The waste incinerator according to Item 5. In a waste incineration method in which waste is incinerated in an incinerator having a dry grate, a combustion grate, and a post-combustion grate, and the incineration ash discharged from the incinerator is cooled in an ash cooling tank.
The primary air is supplied from the primary air supply means below the dry grate and the combustion grate, and a part of the incinerator exhaust gas is supplied from the circulating exhaust gas supply means below the post-combustion grate. The cooling water temperature of the ash cooling tank is measured, and the circulating exhaust gas supply amount supplied below the post-combustion grate is adjusted by the circulating exhaust gas supply amount adjusting means based on the cooling water temperature measurement value measured by the cooling water temperature measuring means. A method of incinerating waste by a waste incinerator, which is characterized by doing so. The waste incineration method according to claim 7, wherein the circulating exhaust gas supply amount is adjusted so that the cooling water temperature of the ash cooling tank is 65 ° C. or lower by the circulating exhaust gas supply amount adjusting means. The waste incineration method according to claim 7 or 8, wherein the ^{circulating exhaust gas supply amount is adjusted to 5} to 20 m 3 per 1 kg of incineration ash discharge by the circulating exhaust gas supply amount adjusting means. The waste incinerator method according to claim 7 or 8, wherein the ^{circulating exhaust gas supply amount is adjusted to 500 to 2000 m 3} per 1 kg of waste incinerator by the circulating exhaust gas supply amount adjusting means. In a waste incineration method in which waste is incinerated in an incinerator having a dry grate, a combustion grate, and a post-combustion grate, and the incineration ash discharged from the incinerator is cooled in an ash cooling tank.
Primary air is supplied below the dry grate, combustion grate, and post-combustion grate from the primary air supply means, and part of the exhaust gas from the incinerator is supplied below the post-combustion grate from the circulating exhaust gas supply means for cooling. The cooling water temperature of the ash cooling tank is measured by the water temperature measuring means, and the circulating exhaust gas supply amount by the primary air / circulating exhaust gas supply amount control means for post-combustion based on the cooling water temperature measurement value measured by the cooling water temperature measuring means. It is characterized in that the adjustment of the circulating exhaust gas supply amount supplied below the post-combustion grate by the adjusting means and the adjustment of the primary air supply amount supplied below the post-combustion grate by the primary air supply amount adjusting means are controlled. Waste incineration method. The 11. Waste incineration method.

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