JP2000291935A - Method and device for waste disposal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lower concentration of dioxins in exhaust gas efficiently, by dispersing sludge and/or sulfur component-containing substances to feed them in a waste hopper, in the case of mixed combustion treatment of wastes and the sludge and/or the sulfur component-containing substances by a waste incinerator. SOLUTION: Wastes containing dioxins are charged into a waste hopper 2 from a waste crane 1, while organic sludge that is generated in a sewage disposal process and/or sulfur component-containing substances (sludge and the like in the following), which are effective in lowering the concentration of dioxins are dispersed and fed on the wastes in the waste hopper 2 via a conveyor 4 from an introduction hole 5. At this time, the sludge and the like infiltrate in the wastes in the waste hopper 2 under their own weight to be mixed with combustible components, moisture, etc., on the average. In this way, the mixed sludge and the like and the wastes are fed into an incinerator from a waste cute 3 for mixed combustion. Thereby, the wastes can be burned efficiently and stably, and the concentration of the dioxins can be lowered.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and apparatus for treating waste, and more particularly to a method and apparatus for treating waste in a waste incinerator for efficiently reducing dioxins.

[0002]

2. Description of the Related Art As an incinerator for incinerating waste such as municipal solid waste and waste plastic (hereinafter referred to as waste), a fluidized bed incinerator disclosed in Japanese Patent Application Laid-Open No. 9-303743 is widely used. Used. A schematic diagram of a typical incinerator is shown in FIG. In the illustrated incinerator, the waste is charged from the charging device 11 and is dried and ignited in the fluidized bed 12 flowing by the flowing air sent from the wind box below the dispersion plate 13. The waste is burned in the freeboard section on the fluidized bed, and after incineration, the exhaust gas is discharged outside the furnace through the furnace outlet 14.

[0003]

In the waste incinerator as described above, the present inventors mixed-burn waste and organic sludge and / or sulfur-containing substances generated in a sewage treatment process. As a result, the dioxin concentration was found to be lower than when only wastes were incinerated.
This is for the following reasons.

[0004] The sulfur content in the sludge and / or sulfur content is H ₂ S, CS ₂ , COS, S during the incineration process.
O ₂ or SO ₃ is present in the furnace. Since these substances have a poisoning effect on copper and similar substances that catalyze the production of dioxins such as dioxin and furan, they can be effectively used in the exhaust gas line after the furnace exit from the high temperature combustion field in the furnace. Dioxins can be suppressed.

[0005] Sludge further contains nitrogen and moisture, which effectively act to suppress the generation of dioxins. Nitrogen in the sludge generates ammonia in the combustion process, particularly under a reducing atmosphere in the primary combustion zone, and this reacts with chlorine compounds. Thereby, the dioxin production reaction of Cl in the process of producing dioxins is suppressed. In addition, the moisture in the sludge can suppress the combustion reaction of combustibles and reduce the generation of soot. If the amount of soot generated can be suppressed, the concentration of aromatic organic compounds resulting therefrom decreases, and as a result, the concentration of dioxin-based substances, which are incomplete combustion products, also decreases.

However, when dioxins are suppressed by co-firing sludge and / or a sulfur component-containing material and waste as described above, unless the respective components are uniformly dispersed and supplied in the furnace, the combustion in the furnace is not performed. The state cannot be kept constant. Further, if the sludge and / or sulfur component-containing material is not supplied uniformly, it is sufficiently considered that a high-temperature and low-temperature region is partially formed in the furnace, and organic gas, unburned gas, and soot may be generated. Can be In this case, the concentration of the aromatic organic compound due to soot increases, and as a result,
In some cases, the concentration of dioxin substances, which are incomplete combustion products, may be rather high.

[0007] Further, in order to put waste and sludge into the furnace from the respective feeders, the incinerator to which the waste is applied is limited to a fluidized bed incinerator. This is because, in the case of a fluidized bed incinerator, a substance (sand) that stores heat is present, whereas in a grate incinerator or a kiln incinerator, such a substance is not present. If sludge with a high moisture content and low calorific value is directly introduced into a grate incinerator, combustion is partially suppressed and uniformity inside the furnace is lost, and in the worst case, the fire goes out. Is also conceivable. Further, sludge before being incinerated may fall from a gap such as a forced air hole of a grate to an ash chute below the grate, and may not be completely incinerated.

[0008] A method and an apparatus for incinerating waste by efficiently co-firing sludge and / or sulfur-containing substances and waste have not yet been obtained.

Accordingly, the present invention is to reduce the concentration of dioxins in exhaust gas by efficiently co-firing sludge and / or sulfur-containing substances and waste such as municipal waste while maintaining the combustion state in the incinerator constant. It is an object of the present invention to provide a method and an apparatus for treating waste which can be made to be able to be processed.

[0010]

In order to solve the above-mentioned problems, the present invention relates to a method for treating waste in which waste and sludge and / or a sulfur component-containing material are co-fired in a waste incinerator. And / or dispersing the sulfur component-containing material and supplying it to a refuse hopper.

The present invention also provides a waste treatment apparatus for co-firing waste and sludge and / or sulfur components in a waste incinerator, wherein the sludge and / or sulfur components are dispersed to a waste hopper. Provided is a processing apparatus comprising a dispersing supply unit for supplying.

Hereinafter, the present invention will be described in detail.

In the present invention, the sludge and / or sulfur component-containing material is dispersed and supplied to the garbage chute by a dispersion supply device having a function of uniformly dispersing and supplying the same. The dispersion supply device is not particularly limited, and any device can be used as long as it has a function of uniformly dispersing the sludge and / or sulfur component-containing material in the garbage chute. For example, a screw conveyor, a mono pump, a sliding conveyor, or a combination thereof may be used.

It is desirable that waste is supplied into the refuse hopper prior to dispersing and supplying sludge and / or sulfur components.

When the sludge is supplied in a dispersed manner, the sludge penetrates into the waste in the refuse hopper by its own weight, and the combustibles, moisture, and the like are evenly dispersed and uniformly mixed with the waste. In the case of a sulfur component-containing material, it is evenly dispersed on the waste and uniformly mixed with the waste. In addition, sludge and / or sulfur-containing substances mixed with the supply of waste into the furnace are also supplied, so that parts with extremely low calorific value and parts with extremely high moisture content are in the furnace. Therefore, stable combustion can be performed in a wide range, and generation of soot can be prevented.

As a dispersion supply device for dispersing and supplying sludge and / or a sulfur component-containing material, it is preferable to use a lance for mixing these and gas and dispersing them to a refuse hopper. Using a lance that uses air, CO _2, or the like as the carrier gas, the sludge and / or sulfur component-containing material can be more uniformly and effectively dispersed in the refuse hopper together with the carrier gas.

It is preferable that the disperse supply of the sludge and / or the sulfur component-containing substance from the dispersion supply device to the waste hopper is performed in accordance with the timing of inputting the waste into the waste hopper by the waste crane. Usually, the waste stored in the waste pit is supplied to a waste hopper by a waste crane at predetermined intervals determined as appropriate. If the sludge and / or the sulfur component-containing material is continuously supplied when the amount of waste is small in the refuse hopper, only the sludge and / or the sulfur component-containing material will be supplied into the incinerator. In addition, if the waste crane is continuously supplying sludge and / or sulfur content while the waste is being thrown into the waste hopper, the sulfur content and waste may be scattered around the waste hopper. Can be Therefore, if the dispersion supply device is driven in accordance with the timing of inputting the waste into the waste hopper, an appropriate amount of the sludge and / or sulfur component-containing material can be efficiently supplied.

For example, the dispersion supply device can be driven by the following method.

(1) After the waste is supplied to the waste hopper by the waste crane, a certain amount of sludge and / or a sulfur component-containing material is dispersed and supplied.

(2) The amount of waste in the refuse hopper is sensed by a sensor, and the amount of sludge is optimal for the amount of waste in the refuse hopper at that time so that the sludge and / or the sulfur component-containing materials are uniformly mixed. And so on.

(3) When the refuse crane puts waste into the refuse hopper, supply of sludge and / or sulfur components is stopped.

(4) The weight of the waste put into the waste hopper by the waste crane is sensed by a weight sensor, and an appropriate amount of sludge and / or a sulfur component-containing material is dispersed and supplied after the waste is thrown. .

These methods can be performed in combination. Further, the present invention is not limited to the four methods described above, and it is also possible to use another method to disperse and supply wastes in accordance with the timing of the waste being put into the garbage hopper.

It is preferable that the dispersion and supply of the sludge and / or the sulfur component content by the above-described method is stopped at least one hour before the operation of the incinerator is stopped. In the incinerator,
Usually, operation adjustment is started several hours before the operation is stopped, and the amount of waste input is reduced. If the sludge and / or sulfur component-containing material is continuously supplied during this time, the following inconvenience occurs. When the sludge is continuously supplied, it is expected that the total heat generation decreases and the combustion state becomes unstable. Further, when the sulfur component-containing substance is continuously supplied, the burning rate of the sulfur component-containing substance increases in the incinerator, and the SO2 in the exhaust gas is reduced.
_x concentration increases.

By stopping the supply of the sludge and / or sulfur component-containing material by the dispersion supply device at least one hour before the operation of the incinerator is stopped, it is possible to avoid the above-mentioned inconveniences and to stop the operation until the operation is stopped. During this time, the combustion state of the incinerator can be prevented from becoming unstable.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to the drawings.

FIG. 1 is a schematic diagram showing an example of a waste disposal apparatus according to the present invention, and shows a portion of a waste hopper of a waste incinerator. The waste is put into the waste hopper 2 from the waste crane 1, while the sludge and / or sulfur component-containing material passes through the sludge and / or sulfur component-containing material inlet 5 through the conveyor 4 and is discharged into the waste hopper. Distributed over

The sludge then penetrates into the waste in the refuse hopper 2 by its own weight, and combustibles and moisture are mixed together on average. Sulfur content is also dispersed evenly over the waste in the garbage hopper and evenly mixed, and in some cases, after that, the sulfur content is mixed as the waste is fed into the furnace. Things are also supplied. In this manner, the sludge and / or sulfur component-containing material is supplied from the refuse chute 3 together with the waste into the furnace (not shown).

FIG. 2 is a schematic view showing another example of the waste disposal apparatus of the present invention, and shows a portion of a waste hopper of a waste incinerator. As in the processing apparatus shown in FIG. 1, the waste is put into a refuse hopper 2 from a refuse crane 1. On the other hand, the sludge and / or sulfur component-containing material is introduced from the sludge and / or sulfur component-containing material introduction port 5, is conveyed from the lance 6 together with the carrier gas supplied from the carrier gas supply port 7, and is transferred to the refuse hopper 2. Distributed and supplied. In this manner, the sludge and / or sulfur component-containing material is efficiently dispersed over the waste in the refuse hopper 2 over a wide range. At this time, as the carrier gas, in addition to air, CO ₂ , nitrogen and the like, an exhaust gas recirculation gas and the like can be used, and the flow rate is not particularly limited as long as the sludge and / or the sulfur component-containing substance can be dispersed. Not done.

The sludge is then removed from the waste hopper 2 by its own weight.
Infiltration into the waste in the garbage, the combustibles, moisture and the like are mixed on average, and the sulfur component-containing material is also dispersed and uniformly mixed on the waste in the garbage hopper. In this manner, the sludge and / or sulfur component-containing material is supplied from the refuse chute 3 together with the waste into the furnace (not shown).

The sludge mixed with waste in the present invention includes sewage sludge, human waste sludge generated during sewage treatment, sludge generated when organic wastewater is treated with activated sludge,
Any type of sludge can be used, such as sludge generated when solid-liquid separation of wastewater containing organic matter, sludge generated in closed water areas during river dredging, and sludge generated in the course of sewage treatment. The water content of the sludge is not particularly limited, either.
Sludge containing water in the usual range of 10 to 90% can be used.

As the sulfur component-containing material, any sulfur component-containing material such as sulfur powder, industrial waste wastewater (because it contains sulfur), and rubber waste such as waste tires can be used. However, when rubber waste such as waste tires is used, it is necessary to operate in consideration of the calorific value.

Further, the above-mentioned sludge and the sulfur component-containing substance can be used in combination.

In the present invention, the type of the incinerator is not limited at all, and it is applicable to any incinerator such as a fluidized bed incinerator, a grate incinerator, a kiln incinerator, etc. Alternatively, it can be co-fired with a sulfur component-containing material, and the temperature of the combustion chamber can be in a normal range.

[0035]

Now, the present invention will be described in further detail with reference to specific examples.

Example 1 A grate incinerator was used as a waste incinerator, and municipal solid waste and sludge as waste were co-fired and treated according to the method of the present invention.

First, sludge was supplied to a garbage hopper in which waste was previously charged by using a lance having a function of mixing sludge and air and dispersing the sludge. At this time, CO ₂ was used as a carrier gas for carrying the sludge. The municipal solid waste is 2300 kcal / kg, and the sludge content is 80%. Drying stage temperature 700-850 ° C, combustion chamber temperature 85
The temperature was changed to 0 to 1000 ° C., and the municipal waste and the sludge were co-fired.

As a result, the average CO concentration was reduced to less than half and the dioxin concentration was reduced by 30% as compared with the case where municipal solid waste and sludge were put into the furnace from separate chutes. During the incineration, the furnace could be operated under stable conditions, and there was no abnormality in the exhaust gas concentration or ash condition.

Example 2 A grate incinerator was used as a waste incinerator, and municipal solid waste and a sulfur component-containing material were mixed and treated according to the method of the present invention.

First, sulfur powder was used as the sulfur component-containing material.
With a function to disperse the sulfur component content
The waste to a waste hopper to which
A yellow component content was supplied. At this time, the sulfur content
The carrier gas to be sent is CO _TwoWas used. Municipal waste is 2
300 kcal / kg, the content of the sulfur component is 80
%. Drying stage temperature 700-850 ° C, combustion chamber temperature
Of municipal solid waste and sulfur powder
And mixed.

As a result, compared with the case where municipal solid waste and sulfur powder were put into the furnace from separate chutes, the average CO
The concentration was reduced to less than half, and the dioxin concentration was also reduced by 20%. During the incineration, the furnace could be operated under stable conditions, and there was no abnormality in the exhaust gas concentration or ash condition.

[0042]

As described above, according to the present invention, the combustion state in the incinerator is kept constant, and the sludge and / or sulfur component-containing material and the waste such as municipal waste are efficiently co-fired, A method and apparatus for treating waste which can reduce the concentration of dioxins in exhaust gas are provided.

By using the present invention, sludge and / or
Alternatively, the sulfur component content and the waste can be uniformly supplied to the refuse hopper, so that they are uniformly supplied even in the furnace. Therefore, the combustion proceeds stably without generating an extremely low calorific value region in the incinerator, and as a result, the generation of dioxins in the exhaust gas can be reduced efficiently.

According to the present invention, it is possible to apply co-firing of sludge and / or a sulfur component-containing material to an incinerator of any type such as a grate incinerator as well as a conventional fluidized bed incinerator. The industrial value is great.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a configuration of an example of a waste disposal apparatus according to the present invention.

FIG. 2 is a schematic diagram illustrating a configuration of another example of the waste disposal apparatus of the present invention.

FIG. 3 is a schematic diagram showing a configuration of a conventional fluidized bed incinerator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Garbage crane 2 ... Garbage hopper 3 ... Garbage chute 4 ... Conveyor 5 ... Sludge and / or sulfur component containing inlet 6 ... Lance 7 ... Carrier gas supply port 11 ... Inputting machine 12 ... Fluidized bed 13 ... Dispersion plate 14 ... Furnace outlet

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme court ゛ (Reference) F23G 7/04 601 F23G 7/04 601N F23K 3/18 F23K 3/18 (72) Inventor Takashi Noto Tokyo 1-1-2 Marunouchi, Chiyoda-ku Nippon Kokan Co., Ltd. (72) Inventor Seiichi Noguchi 3-7 Bentencho, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture F-ku Plant Construction Co., Ltd. AC01 AC02 AC20 BA05 BA07 CA01

Claims (8)

[Claims] 1. A waste treatment method in which waste is mixed with sludge and / or sulfur components in a waste incinerator, wherein the sludge and / or sulfur components are dispersed and supplied to a garbage hopper. A processing method characterized in that: 2. The method of claim 1, wherein the sludge and / or sulfur component-containing material is dispersed and supplied to the refuse hopper by mixing and supplying the sludge and / or sulfur component-containing material with a gas. Waste treatment method as described. 3. The waste hopper according to claim 1, wherein the sludge and / or the sulfur component-containing material are dispersed and supplied to the waste hopper in synchronization with a waste crane that loads waste into the waste hopper. the method of. 4. The dispersion supply of the sludge and / or sulfur component-containing material to the waste hopper is stopped at least one hour before the operation of the waste incinerator is stopped.
4. The method according to any one of the above items 3. 5. A waste treatment apparatus for mixing and burning waste and sludge and / or sulfur component-containing material in a waste incinerator, wherein the sludge and / or sulfur component-containing material is dispersed and supplied to a waste hopper. A processing apparatus comprising a supply unit. 6. The dispersing and supplying means, wherein the sludge and / or
Alternatively, a mixture of a sulfur component-containing substance and a gas is used to mix sludge and / or
6. The waste treatment apparatus according to claim 5, wherein the lance has a function of dispersing and supplying a sulfur component-containing substance to the refuse hopper. 7. The waste treatment apparatus according to claim 5, wherein said dispersion supply means is means for driving the waste hopper in accordance with a charging timing of a waste crane for charging the waste into the waste hopper. 8. The dispersing and supplying means, wherein the sludge and / or
The waste treatment apparatus according to any one of claims 5 to 7, wherein the supply of the sulfur component-containing substance to the refuse hopper is stopped at least one hour before the operation of the waste incinerator is stopped.