JPH07323213A - Method for making harmless harmful material in waste incinerator and device therefor - Google Patents

Abstract

PURPOSE:To obviate the installation of a special device for removing harmful components contained in water by feeding the water produced by thermal decomposition into a combustion chamber of a waste incineration furnace. CONSTITUTION:After waste gas leaving a waste incineration furnace 2 is cooled by a temp. adjusting tower 4, a reaction agent is added to it, and the formed reaction product is collected together with flying ash by a bag filter 6. The reaction product is transferred together with the flying ash to a thermal decomposition device 12, where a harmful material, dioxins, is thermally decomposed. The produced water is stored in a storage tank 14 as drainage. The drainage contg. the dioxins is fed to a sewage tank 9 through drainage feeding piping 16. The drainage is sprayed together with the sewage to a high temp. zone in a combustion chamber of the waste incineration furnace 2 through sewage feeding piping 11. That is, the dioxins are thermally decomposed and made harmless in the waste incineration furnace 2. Therefore, harmful materials are made harmless without installing a special device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for detoxifying harmful substances in a refuse incineration facility.

[0002]

2. Description of the Related Art Generally, combustion exhaust gas discharged from a refuse incinerator is discharged from a chimney to the atmosphere through a boiler, a temperature control tower, a bag filter and a wet smoke washing device.

The fly ash collected by the bag filter contains harmful components such as dioxins. The dioxins are pyrolyzed by a pyrolysis device and then passed through a fly ash detoxification device. Have been discharged.

By the way, this pyrolysis apparatus has already been proposed by the present inventors. That is, this thermal decomposition device has a screw conveyor inside and holds fly ash under oxygen deficiency and at a temperature of 300 ° C. or higher for 30 minutes or more to decompose dioxins which are harmful substances in fly ash. Ash heating device, an ash cooling device that cools the fly ash discharged from this ash heating device, an ash bunker that stores the fly ash that has been cooled to a specified temperature or lower by this ash cooling device, and an evaporating device that uses the ash heating device. , A temperature control tower that cools the exhaust gas containing low boiling heavy metals such as volatilized mercury and undecomposed dioxins, and a drain tank that stores the condensate condensed in this temperature control tower,
It is composed of an activated carbon filter that adsorbs harmful substances contained in the exhaust gas that has not condensed in the temperature control tower.

[0005]

By the way, as described above, when dioxins are pyrolyzed by the ash heating device and then condensed in the temperature control tower, dioxins are contained in the condensate accumulated in the drain tank. Is found to contain
Therefore, this drain water also needs to be detoxified, and there is a problem that an expensive detoxification device must be separately provided.

Therefore, an object of the present invention is to provide a detoxifying method and a detoxifying device for harmful substances in a refuse incinerator which can solve the above problems.

[0007]

In order to solve the above problems, the method for detoxifying harmful substances in a refuse incinerator according to the present invention is a method in which a reaction aid is added to exhaust gas discharged from a refuse incinerator to remove harmful components. And the reaction material is collected together with the fly ash by a collection device, and the fly ash containing the collected reaction material is thermally decomposed by a thermal decomposition device, and the water generated by this thermal decomposition is converted into the above-mentioned dust. This is a method of supplying it into the combustion chamber of the incinerator.

The detoxifying device for harmful substances in the refuse incinerator of the present invention comprises a reaction aid adding device for adding the reaction aid to the exhaust gas discharged from the waste incinerator and the reaction aid. A collection device that collects the reactive substances in the exhaust gas together with the fly ash, a thermal decomposition device that thermally decomposes the reactive substances collected by the collection device together with the fly ash, and the water generated by the thermal decomposition device is stored. Of harmful substances in the waste incinerator, which consists of a storage tank and a supply pipe that supplies the water in this storage tank to the combustion chamber of the waste incinerator directly or via the waste water tank of the waste incinerator. It is an oxidizer.

[0009]

According to the method and apparatus for detoxifying harmful substances described above, since the water containing the harmful components generated from the thermal decomposition device is returned to the waste incinerator again, the harmful components contained in the moisture are included. Is rendered harmless by thermal decomposition.

Therefore, it is not necessary to provide a special detoxifying device for removing harmful components contained in water.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for detoxifying harmful substances and a detoxifying device according to an example of the present invention will be described below with reference to FIG.

First, a schematic structure of the entire refuse incineration facility will be described. That is, this waste incineration facility includes a waste pit 1, a waste incinerator 2, a crane device 3 for loading the waste in the waste pit 1 into the waste incinerator 2, a boiler unit 2a from the waste incinerator 2. A temperature control tower 4 that cools the combustion exhaust gas discharged through the reactor, and a reaction aid addition device 5 that adds a reaction aid [for example, Ca (OH) ₂ ] to the exhaust gas discharged from the temperature control tower 4, A bag filter 6 which is a trapping device for trapping together with the fly ash the reaction substance produced by adding the reaction aid, a wet cleaning device 7 for wet-cleaning the exhaust gas discharged from the bag filter 6, and the wet cleaning device. A chimney 8 for discharging the exhaust gas emitted from 7 to the atmosphere, a sewage tank 9 for storing the sewage discharged from the trash pit 1, and a sewage transfer pump 10 on the way are provided for sewage incineration of the sewage tank 9. Sewage supply to the high temperature area in the combustion chamber of furnace 2. The Hagenmeier method for guiding the tube 11 and fly ash (hereinafter, simply referred to as fly ash) containing the reaction substance collected by the bag filter 6 and thermally decomposing dioxins which are harmful components in the fly ash. A thermal decomposition device (having the same configuration as that described in the conventional example) 12 and a fly ash after the dioxins have been thermally decomposed by this thermal decomposition device 12 are introduced to make them harmless. Device 13, a storage tank 14 for storing the drain water (moisture) generated in the thermal decomposition device 12, and a drain water transfer pump 15 in the middle of the storage tank 14 for drain water from the storage tank 14 to the waste water. It is composed of a drain water supply pipe 16 which is supplied into the tank 9.

The above-mentioned fly ash detoxification device is also equipped with a harmful heavy metal (for example, Pb, H) when the fly ash is dumped in the landfill.
g, Cd, etc.) are not solidified by, for example, a cement solidification method. Other detoxifying methods include a melting method, a chelating method, and an acid extracting method.

Next, detoxification of dioxins which are harmful components (hazardous substances) in exhaust gas will be described.
The exhaust gas discharged from the refuse incinerator 2 is cooled in the temperature control tower 4 and then the reaction aid is added, and the reaction substance generated thereby is collected by the bag filter 6 together with the fly ash.

This reaction material is pyrolyzed together with the fly ash 1
2, the dioxin, which is a harmful component, is thermally decomposed by being held at a predetermined temperature for a predetermined time. And
The water generated in the thermal decomposition device 12, that is, the water generated when the exhaust gas discharged from the ash heating device is condensed by cooling, is stored in the storage tank 14 as drain water.
The drain water contains dioxins, though a trace amount.

The drain water containing the dioxins is
It is supplied to the dirty water tank 9 through the drain water supply pipe 16. Then, the drain water supplied into the sewage tank 9 together with the sewage flows through the sewage supply pipe 11 to the waste incinerator 2
It is sprayed and heated in the high temperature region of the combustion chamber. That is, dioxins are thermally decomposed and rendered harmless in the refuse incinerator 2.

As described above, the drain water containing a small amount of dioxins generated in the thermal decomposition device 12 for thermally decomposing dioxins is supplied to the waste water tank 9, and the waste water is burned in the waste incinerator 2 together with the waste water. Since it is spray-supplied into the room and pyrolyzed, it is not necessary to separately provide a detoxification device for dioxins, and it is possible to detoxify the drain water containing dioxins at a very low cost. The running cost can be almost eliminated.

By the way, in the above embodiment, the drain water discharged from the thermal decomposition apparatus 12 is once supplied to the waste water tank 9 and then to the refuse incinerator 2. For example, the wavy line in FIG. As shown in, drain water supply pipe 16
May be directly connected to the refuse incinerator 2 and sprayed in a high temperature region in the combustion chamber.

In this case, some trouble (for example, in the sewage supply system on the sewage tank 9 side, that is, the sewage supply pipe 11)
If the waste water transfer pump 10 fails), the drain water can be rendered harmless without any trouble.

The above-mentioned method for detoxifying harmful substances is
In addition to the drain water discharged from the thermal decomposition apparatus 12, it can be applied to detoxification of the drain water that is generated in the same refuse incinerator and also contains dioxins.

[0021]

As described above, according to the method and apparatus for detoxifying harmful substances of the present invention, the water containing harmful components such as dioxins generated from the thermal decomposition device is stored in the combustion chamber of the refuse incinerator. Since the toxic substance contained in the water is supplied, the toxic substance contained in the water is detoxified by thermal decomposition. Therefore, the toxic substance can be detoxified without providing a special detoxification device. That is, the harmful components can be rendered harmless at a very low cost and with almost no running cost.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic overall configuration of a refuse incineration facility according to an embodiment of the present invention.

[Explanation of symbols]

 1 Waste Incinerator 5 Reaction Aid Addition Device 6 Bag Filter 9 Sewage Tank 10 Sewage Transfer Pump 11 Sewage Supply Pipe 12 Pyrolysis Device 13 Fly Ash Detoxification Device 14 Storage Tank 15 Drain Water Transfer Pump 16 Drain Water Supply Pipe

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location B09B 3/00 B09B 3/00 ZAB 303 L 304 G (72) Inventor Noriyuki Nakamura Osaka-shi, Osaka 5-3-2, Nishikujo, Nishi-ku, Hitachi Shipbuilding Co., Ltd.

Claims (2)

[Claims] 1. A reaction auxiliary agent is added to exhaust gas discharged from a refuse incinerator to react with harmful components, the reaction material is collected together with fly ash by a collector, and the collected reaction material is collected. A method for detoxifying harmful substances in a refuse incinerator, which comprises thermally decomposing fly ash containing slag with a thermal decomposition device and supplying moisture generated by the thermal decomposition to the combustion chamber of the refuse incinerator. 2. A reaction auxiliary agent adding device for adding a reaction auxiliary agent to the exhaust gas discharged from the refuse incinerator, and a collecting device for collecting the reaction substances in the exhaust gas to which the reaction auxiliary agent has been added together with fly ash. And a pyrolysis device that pyrolyzes the reaction material collected by this collection device together with fly ash, a storage tank that stores the water generated in this pyrolysis device, and the water in this storage tank that is incinerated by garbage. An apparatus for detoxifying harmful substances in a waste incinerator, comprising a supply pipe for supplying the wastewater to a combustion chamber of the waste incinerator through a waste water tank in the facility or directly.