JP3531791B2 - Method and apparatus for melting incinerated fly ash - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method of melting the incineration fly ash, in particular, a method of melting the stoker fly ash and fluidized fly ash generated when incinerating solid wastes such as municipal waste
Regarding the device .

[0002]

2. Description of the Related Art Conventionally, fly ash collected by a dust collector when incinerating municipal solid waste in an incinerator has a problem that heavy metals and the like are eluted, and at present, it cannot generally be landfilled as it is. , Could not be disposed of without detoxifying it by the following four methods specified by the Minister of Health and Welfare. Melt solidification Cement solidification Chemical treatment Stabilization with acids and other solvents Among them, incineration fly ash contains highly poisonous dioxins, so it is possible to insolubilize heavy metals and decompose dioxins at the same time, and landfill. The most effective method is the melting and solidification method of incineration fly ash that can prolong the life of the earth. Furthermore, slag formed by melting and solidifying fly ash has been attracting attention as a recycled material that can be effectively used.

There are the following methods for melting and solidifying incineration fly ash. Fly ash discharged from the stoker type municipal waste incinerator,
Melting process by mixing with glass or incineration ash to lower melting point, melting fly ash discharged from fluidized bed incinerator alone, and stoker fly ash is difficult to melt unless However, it is difficult to operate the melting furnace continuously for a long period of time. That is, since fly ash generally contains slaked lime used to remove harmful gases such as hydrogen chloride in the treatment of exhaust gas from incinerators, it has a high melting point, an increase in the unit energy of melting energy, and the temperature inside the furnace and the temperature of the molten metal. There were adverse effects such as wear of refractory in the melting furnace due to the rise.

Therefore, it has been considered difficult to melt unless the melting temperature is lowered by lowering the basicity by mixing with stoker incinerated ash or glass containing silicon. However, the stoker fly ash is
Even if mixed with incinerated ash or glass waste (about 1), which has a small apparent specific gravity (0.3 to 0.4) and a large apparent specific gravity, it cannot be sufficiently mixed due to the difference in specific gravity, and the basicity fluctuates and melts. The temperature changed and stable operation was not possible. On the other hand, fluid fly ash, like stoker fly ash, cannot be landfilled without detoxification treatment specified by the Minister of Health and Welfare, but because of the inclusion of fluid sand used in fluidized bed incinerators, the stoker is a component. It is known that it is similar to the incineration ash of the incinerator, and that the melting operation is possible without increasing the melting temperature as it is.

[0005]

In view of the above-mentioned prior art, the present invention is capable of lowering the melting point of stoker fly ash without mixing with ash or incinerator ash incinerator furnace, reducing melting energy and refractory materials. It is an object of the present invention to provide a method and an apparatus for melting incineration fly ash, which suppresses the wear of the incinerator and enables stable operation.

[0006]

In order to solve the above-mentioned problems, in the present invention, fly ash generated from a stoker type incinerator for incinerating waste such as municipal solid waste and fly ash generated from a fluidized bed type incinerator. This is a method for melting incineration fly ash, which is characterized in that ash and ash are mixed at a fixed ratio and melted in an ash melting furnace. In the melting method, the stoker fly ash and the fluid fly ash are preferably mixed uniformly, and the fixed ratio is 1 or more of the fluid fly ash, preferably 2 to 1 of the stoker fly ash. A ratio of 3 is good. In the present invention, the ash is melted.
A melting furnace that melts and a stove that incinerates waste such as municipal waste
Fly ash from mosquito type incinerator and from fluidized bed type incinerator
Means for mixing the fly ash to be mixed at a constant ratio,
And a means for supplying ash to the melting furnace.
This is a melting device for incinerated fly ash.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to fly ash generated by incinerating waste such as municipal waste in a stoker type incinerator and fly ash generated by incinerating municipal waste in a fluidized bed type incinerator. As a pre-melting treatment, the mixture is uniformly mixed at a fixed ratio and then placed in an ash melting furnace to perform the melting treatment. Generally, a stoker type incinerator and a fluidized bed type incinerator are not installed in the neighborhood, but in the case where fly ash generated from multiple municipal waste incinerators is ash melted in one place, Fluid fly ash is mixed and processed (called the center method). Thus, in the present invention, the stoker fly ash and the fluidized fly ash are uniformly mixed by a mixer as a pre-melting treatment at a constant ratio to lower the melting point of the fly ash and prolong the life of the melting furnace refractory. In addition, the bulk density can be increased and stable treatment can be performed.

Next, the present invention will be described in detail with reference to the drawings. FIG. 1 shows a schematic configuration diagram of an apparatus for carrying out the melting method of the present invention. In FIG. 1, 1 is fluid fly ash, 2
Is a stoker fly ash, 3 and 4 are storage hoppers, 5 and 6 are ash scales, 7 and 8 are ash supply conveyors, 9 is a mixing device, 10 is an ash supply device, 11 is an ash melting furnace, 12 is a plasma torch, 1
3 is slag and 14 is exhaust gas. The method of the present invention will be described with reference to FIG.

First, both the stoker fly ash 2 and the fluidized fly ash 1 are transported by a truck from an urban refuse incineration plant,
Accepted to each hopper 3, 4. When the amount of incineration is the same, the generation ratio of stoker fly ash and fluid fly ash from the incineration plant is about 1: 2 to 1: 3. In the present invention, basically, the larger the amount of the fluid fly ash, the more the handling (treatment) becomes easier, but it is not preferable that one remains, so that the fluid fly ash is treated in a large amount within the processable range. Is good. Table 1 shows the melting point measurement results of stoker fly ash, fluid fly ash and a mixture thereof. Both the stoker fly ash and the fluid fly ash in Table 1 are fly ash generated by incineration of municipal solid waste, and both contain slaked lime used dry as a neutralizing agent when treating incineration exhaust gas and have a general composition. .

[0010]

[Table 1]

Next, the two types of fly ash cut out from these hoppers 3 and 4 are ash scales 5 and 6 and conveyors 7 and 8, respectively.
The mixture was mixed in a twin-screw type mixing device 9 in the subsequent stage so as to be substantially uniform for a certain period of time. Mixing device 9
May be a paddle rotating type, a rotating drum type or the like as long as a uniform mixing effect can be obtained. It is even more effective if the mixed fly ash is molded with a molding machine. The mixing ratio in this case is, as shown in FIG. 2, basicity (CaO / Si
It is preferable that the stoker fly ash: fluid fly ash = 1: 2 to 1: 3 so that O ₂ ) is 2 or less, preferably about 1.5 to 2. When the exhaust gas treatment of the incinerator does not use slaked lime for both the stoker and the fluidized bed incinerator, the basicity is 1 or less for both the stoker fly ash and the fluid fly ash, so the mixing ratio can be set arbitrarily (in other words, mixing is necessary. Not). Melting furnace 11
Operated in an electric melting plasma torch batch melting furnace. The melting furnace may be a fuel type or a continuous type.

[0012]

EXAMPLES The present invention will be specifically described below with reference to examples. Example 1 Using the apparatus shown in FIG. 1, mixed fly ash (Example) in which the mixing ratio of stoker fly ash and fluidized fly ash was 1: 3, and mixing ratio of stoker fly ash and stoker incinerated ash was 1: 3. And a mixed ash (comparative example) was used to perform a melting test. Table 2 shows the processing conditions and results at that time.

[0013]

[Table 2]

From these results, at a mixing ratio in the range of basicity of 1.5 to 2, the melting point is constantly about 1400 ° C. or less, the wear of refractory is suppressed, and the melting furnace repair interval is twice as long as the conventional one. Extended to a degree. On the other hand, when the stoker fly ash and the stoker incineration ash are mixed as in the conventional case, the higher the fly ash mixing ratio (incineration fly ash 1 to incineration ash 4 or less), the more difficult it is to uniformly mix the base. As a result of variations in the degree and the melting point of the molten metal, the melting power fluctuates, and the wear of the refractory is promoted. The refractory in the melting furnace is worn away at the interface between the liquid phase which is the molten metal and the vapor phase of the atmospheric gas, that is, the part where the molten metal flows. The bulk specific gravity of the stoker fly ash is 0.35 to 0.5, and the bulk specific gravity of the fluid fly ash is 0.7.
Since it is a degree, it became 0.5 to 0.65 in the above mixing ratio. With the above-mentioned bulk specific gravity, fly ash is difficult to fly in the furnace,
The inside of the furnace and the tap hole can now be monitored. In the conventional mixed ash fusion of stoker fly ash and incineration ash, mixing is not sufficient, so if it is supplied into the furnace in a mixed state with a low bulk specific gravity, scattering occurs, monitoring is difficult and stable melting operation was not possible. .

[0015]

According to the present invention, the stoker fly ash and the fluid fly ash are uniformly mixed at a constant ratio and melt-treated,
The melting point was lowered, melting operation with less wear of refractory was possible, and the bulk specific gravity was increased and stable treatment was possible.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an example of an apparatus for carrying out a melting method of the present invention.

FIG. 2 is a graph showing the relationship between ash basicity and melting point (° C.).

[Explanation of symbols]

1: Fly fly ash, 2: Stalker fly ash, 3, 4: Storage hopper, 5, 6: Ash meter, 7, 8: Ash supply conveyor, 9:
Mixing device, 10: Ash supply device, 11: Ash melting furnace, 12:
Plasma torch, 13: Slag, 14: Exhaust gas

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Claims (4)

(57) [Claims] 1. Fly ash generated from a stoker-type incinerator that incinerates waste such as municipal waste and fly ash generated from a fluidized-bed-type incinerator are mixed at a fixed ratio and melted in an ash melting furnace. A method for melting incinerated fly ash, which is characterized in that 2. The mixing of the stoker fly ash and the fluid fly ash,
The method for melting incinerated fly ash according to claim 1, wherein the method is a uniform mixing. 3. The fixed ratio is 1 or more fluid fly ash to 1 stoker fly ash.
Alternatively, the method for melting incinerated fly ash according to 2 above. 4. A melting furnace for melting ash, and waste such as municipal waste
Fly ash and flow from a stoker incinerator that incinerates waste.
The fly ash obtained from the moving bed incinerator is mixed at a constant ratio.
And means for supplying the mixed ash to the melting furnace
Melter baked却飛ash comprising the and.