JP3025149B2 - Method and device for detoxifying harmful substances in refuse incineration plant - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

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

[0003] The fly ash collected by the bag filter contains harmful components such as dioxins. The dioxins are thermally decomposed by a pyrolysis device and then passed through a fly ash detoxification device. Has been discharged.

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

[0005]

As described above, when dioxins are thermally decomposed by an ash heating device and condensed in a temperature control tower, dioxins are condensed in a drain tank. Is included,
Therefore, this drain water also needs to be subjected to detoxification treatment, and there is a problem that an expensive detoxification device must be separately provided.

Accordingly, an object of the present invention is to provide a method and a device for detoxifying harmful substances in a refuse incineration plant which can solve the above-mentioned problems.

[0007]

Means for Solving the Problems To solve the above problems, a method for detoxifying harmful substances in a refuse incineration plant according to the present invention comprises adding a reaction aid 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, the fly ash containing the collected reaction material is thermally decomposed by a pyrolysis device, and the moisture generated by the pyrolysis is removed from the refuse. This is a method of supplying into the combustion chamber of an incinerator.

Further, the detoxifying apparatus for harmful substances in the refuse incineration plant of the present invention includes a reaction aid adding apparatus for adding a reaction aid to exhaust gas discharged from a refuse incinerator, and a reaction aid. A collector that collects the reactants in the exhaust gas with fly ash, a pyrolyzer that thermally decomposes the reactants collected by this collector together with fly ash, and stores the water generated by this pyrolyzer Hazardous substances in refuse incineration facilities consisting of a storage tank to be used and a supply pipe for supplying water in this storage tank to the combustion chamber of the refuse incinerator through a wastewater tank in the refuse incinerator or directly Device.

[0009]

According to the method and apparatus for detoxifying harmful substances described above, the water containing harmful components generated from the pyrolysis device is returned to the refuse incinerator again. Is rendered harmless by thermal decomposition.

Therefore, there is no need to provide a special detoxifying device for removing harmful components contained in water.

[0011]

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

First, a schematic configuration of the entire refuse incineration facility will be described. That is, this refuse incineration equipment includes a refuse pit 1, a refuse incinerator 2, a crane device 3 for putting refuse in the refuse pit 1 into the refuse incinerator 2, and a boiler unit 2a from the refuse incinerator 2. A temperature control tower 4 for cooling the combustion exhaust gas discharged through the reaction apparatus, a reaction aid addition device 5 for adding 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 collecting device for collecting a reaction substance generated by adding a reaction assistant together with fly ash, a wet cleaning device 7 for wet cleaning exhaust gas discharged from the bag filter 6, and a wet cleaning device 7 has a chimney 8 for discharging exhaust gas discharged to the atmosphere, a sewage tank 9 for storing sewage discharged from the refuse pit 1, and a transfer pump 10 for sewage in the middle of the sewage tank 9. Supply of sewage to be supplied to the high temperature area in the combustion chamber of furnace 2 A Hagen-Meier method for guiding a fly ash (hereinafter, simply referred to as fly ash) containing a reactant collected by the tube 11 and the bag filter 6 and thermally decomposing dioxins which are harmful components in the fly ash. Pyrolysis apparatus (having the same configuration as that described in the conventional example) 12 and fly ash which is detoxified by introducing fly ash after dioxins are thermally decomposed by the pyrolysis apparatus 12 , A storage tank 14 for storing drain water (moisture) generated in the pyrolysis device 12, and a drain water transfer pump 15 provided on the way to drain the drain water in the storage tank 14 into the sewage water. And a drain water supply pipe 16 to be supplied into the tank 9.

Further, the fly ash detoxifying apparatus is capable of removing harmful heavy metals (eg, Pb, H) when dumping fly ash into a landfill.
g, Cd, etc.) are solidified by, for example, a cement solidification method. Other detoxifying methods include a melting method, a chelating method, and an acid extracting method.

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

This reactant is combined with fly ash in the thermal decomposition unit 1
2, where it is held at a predetermined temperature for a predetermined time to thermally decompose harmful dioxins. 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.
This drain water contains a small amount of dioxins.

The drain water containing dioxins is
The water is supplied to the sewage tank 9 via a drain water supply pipe 16. The drain water supplied into the sewage tank 9 together with the sewage is supplied to the refuse incinerator 2 via the sewage supply pipe 11.
Is sprayed and heated in a high temperature region in the combustion chamber. That is, dioxins are decomposed by being thermally decomposed in the refuse incinerator 2.

As described above, the drainage water generated in the pyrolysis apparatus 12 for pyrolyzing dioxins and containing a small amount of dioxins is supplied to the sewage tank 9 and the wastewater is burned in the refuse incinerator 2 together with the sewage. Since it is made to spray and supply indoors and thermally decompose, there is no need to separately provide a detoxification device for dioxins, so that detoxification of drain water containing dioxins can be performed at very low cost. Also, the running cost can be almost eliminated.

By the way, in the above embodiment, the drain water discharged from the thermal decomposition unit 12 is once supplied to the sewage tank 9 and then supplied to the refuse incinerator 2. , The drain water supply pipe 16
May be directly connected to the refuse incinerator 2 and sprayed on a high temperature region in the combustion chamber.

In this case, the sewage supply system on the sewage tank 9 side, that is, the sewage supply pipe 11 has some trouble (for example,
When the sewage transfer pump 10 fails, the drain water can be detoxified without any trouble.

The above harmless substance detoxifying method is as follows.
In addition to the drain water discharged from the thermal decomposition device 12, the present invention can be applied to detoxification of drain water generated in the same refuse incineration equipment and containing dioxins.

[0021]

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

[Brief description of the drawings]

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

[Explanation of symbols]

 Reference Signs List 1 refuse incinerator 5 reaction aid addition device 6 bag filter 9 sewage tank 10 sewage transfer pump 11 sewage supply pipe 12 thermal decomposition device 13 fly ash detoxification device 14 storage tank 15 drain water transfer pump 16 drain water supply pipe

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Noriyuki Nakamura 5-3-28 Nishikujo, Konohana-ku, Osaka-shi, Hitachi Zosen Corporation (56) Reference JP-A-5-146772 (JP, A) JP-A-5-33914 (JP, A) JP-A-5-23540 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B01D 53/34-53/88 B09B 3/00

Claims (2)

(57) [Claims] 1. An exhaust gas discharged from a refuse incinerator is added with a reaction aid to react with harmful components, and this reactant is collected together with fly ash by a collector, and the collected reactant is collected. A method for detoxifying harmful substances in a refuse incineration plant, comprising thermally decomposing fly ash containing water by a pyrolysis apparatus and supplying water generated by the pyrolysis to the combustion chamber of the refuse incinerator. 2. A reaction assistant addition device for adding a reaction assistant to exhaust gas discharged from a refuse incinerator, and a collection device for collecting a reaction substance in the exhaust gas to which the reaction assistant has been added together with fly ash. And a pyrolysis device that pyrolyzes the reactants collected by the collection device together with fly ash, a storage tank that stores the water generated by the pyrolysis device, and incinerates the water in the storage tank. A detoxifying apparatus for harmful substances in refuse incineration facilities, comprising a supply pipe for supplying directly into a combustion chamber of a refuse incinerator through a sewage tank in the facility or directly.