JPH05137813A - Thermal decomposition of organic chlorine compound - Google Patents

Abstract

PURPOSE:To reclaim or recycle waste wood containing organic chlorine antiseptics and burnt-up or flying ashes containing dioxin by making them innoxious. CONSTITUTION:An organic chlorine compound is thermally decomposed while reducing gas is allowed to pass through disposals containing the organic chlorine compound. By this thermal decomposition, dioxin in burnt-up or flying ashes and organic chlorine antiseptics in waste wood can be decomposed and made innoxious quickly at a relatively low temperature.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for thermally decomposing dioxin contained in ash discharged from a refuse incinerator and organic chlorine compounds such as trichlorophenol contained in wood as an antiseptic, which have become a problem recently. It is about.

[0002]

2. Description of the Related Art Conventionally, since there is no environmental regulation for dioxin, incineration ash discharged from a refuse incinerator and fly ash collected by an electric dust collector or a bag filter are untreated and landfilled. There was a risk that dioxins in the ash could flow out.

Recently, a research report has been made on detoxification of dioxin in ash by thermal decomposition treatment.
In addition to the need for a high temperature of 00 ° C. or higher, a new problem of volatilization of heavy metals occurred, and a long processing time of 2 hours or more was required.

Regarding the organic chlorine-based preservatives such as trichlorophenol, which is a precursor of dioxin, the waste wood containing this was simply burnt or landfilled. Therefore, there is a possibility that trichlorophenol may flow out from this treated product, and that dioxins may be generated from the outflowing trichlorophenol.

[0005]

In recent years, dioxin has become a problem because it adversely affects the human body and the environment, and regulations have been issued to prevent the generation of dioxins. As a result of this regulation, ash containing dioxin and waste wood containing dioxin precursors cannot be landfilled. Also,
When waste wood is incinerated, it becomes impossible to incinerate the waste wood because dioxins are generated from organic chlorine preservatives such as trichlorophenol.

Further, the conventional thermal decomposition method of the organic chlorine compound requires the treatment conditions of high temperature and long time as described above.

In view of the above situation, an object of the present invention is to provide a method capable of rapidly decomposing / detoxifying dioxin in incinerated ash or fly ash and organochlorine preservative in rot wood at a relatively low temperature. It is in.

[0008]

The method for thermally decomposing organic chlorine compounds according to the present invention has been devised to achieve the above object, and a reducing gas is passed through an object to be treated containing an organic chlorine compound. However, it is characterized by thermally decomposing an organic chlorine compound.

Typical examples of the organic chlorine compound to be treated by this thermal decomposition method are dioxin contained in the ash discharged from the refuse incinerator and trichlorophenol contained in wood as a preservative. Trichlorophenol is a dioxin precursor as described above.

A typical example of the reducing gas is ammonia gas. Ammonia gas is supplied to the thermal decomposition reaction in the form of being contained in the circulating gas. Nitrogen gas is preferable as the circulating gas in terms of price. The amount of ammonia gas in the circulating gas is preferably about 1% by volume.

The thermal decomposition condition of the organic chlorine compound is, for example, about 300 ° C. for about 30 minutes.

[0012]

EXAMPLES Next, examples of the present invention will be given to specifically explain the present invention.

Example Trichlorophenol, which is one of the harmful organochlorine compounds contained in waste wood, was used for the following procedure.

(I) First, 2,4,6-trichlorophenol (hereinafter abbreviated as TCP) was impregnated and supported on diatomaceous earth, which is a simulated untreated substance, and dried to prepare a sample for experiment. This sample was subjected to alcohol extraction treatment, and the extract was analyzed by liquid chromatography. TCP
Was impregnated and supported in the sample in an amount of 9.9 mg / g (diatomaceous earth).

(Ii) 2.5 g of the above sample was filled in a quartz reaction tube set in a test tubular electric furnace, and a heat treatment was carried out at 300 ° C., while a nitrogen gas containing 1% by volume of ammonia gas was added at a rate of 0. The reaction tube was flowed at a rate of 3 l / min for 30 minutes.

(Iii) Next, at the outlet of the reaction tube, the TCP concentration in the outlet gas and the residual TCP amount in the treated sample were analyzed by the same method as described above. As a result, TCP was decomposed in the outlet gas. The less polar substance produced by
The amount corresponding to the TCP content of the sample before treatment was detected, and the residual TCP amount in the sample after treatment was not detected.

Therefore, the TCP decomposition rate is almost 100%.
Met.

Comparative Example In step (ii) of the example, nitrogen gas containing no ammonia gas was flown through the reaction tube, and other operations were performed in the same manner as in the example.

As a result of the analysis in the step (iii), it was confirmed that the TCP concentration in the outlet gas of the reaction tube was almost equal to the TCP content of the untreated sample, and TCP was volatilized without being decomposed by the flowing gas. It was

[0020]

According to the thermal decomposition method of the present invention, dioxins in incinerated ash or fly ash and organochlorine preservatives in humus can be rapidly decomposed and rendered harmless at relatively low temperatures.

Therefore, by detoxifying the waste wood containing the organochlorine preservative and the incinerated ash or fly ash containing dioxins by this method, they can be landfilled or reused.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Toshio Hama 5-3-8 Nishikujo, Konohana-ku, Osaka City Hitachi Shipbuilding Co., Ltd. (72) Toshihiko Yasuda 5-3-28 Nishikujo, Konohana-ku, Osaka Inside Hitachi Shipbuilding Co., Ltd. (72) Kanshi Ota, 5-3 28 Nishi-Kujo, Konohana-ku, Osaka City Inside Hitachi Shipbuilding Co., Ltd. (72) Rikio Shinohara 5-3 28, West Kujo, Konohana-ku, Osaka Inside Hitachi Shipbuilding Co., Ltd. (72) Inventor Shoichi Tanaka 5-3-2, Nishikujo 5-chome, Konohana-ku, Osaka City Inside Hitachi Shipbuilding Co., Ltd.

Claims (1)

[Claims] 1. A method for thermally decomposing an organic chlorine compound, which comprises thermally decomposing an organic chlorine compound while circulating a reducing gas through an object to be treated containing the organic chlorine compound.