JP2741293B2 - Thermal decomposition method of organic chlorine compounds - 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 for thermally decomposing dioxin in ash discharged from a garbage incinerator and organochlorine compounds such as trichlorophenol contained in wood as a preservative, which have recently become a problem. is there.

[0002]

2. Description of the Related Art Conventionally, there has been no environmental regulation on dioxins, so incinerated ash discharged from refuse incineration plants and fly ash collected by electric dust collectors or bag filters have been landfilled without treatment. Dioxin in the ash could be spilled.

Recently, studies have been made on the detoxification of dioxin in ash by thermal decomposition treatment.
In addition to the necessity of a high temperature of 00 ° C. or more, a new problem of volatilization of heavy metals occurs, and a long processing time of 2 hours or more is required.

[0004] Further, with respect to organochlorine-based preservatives such as trichlorophenol which is a precursor of dioxin, waste wood containing the same is simply burned or landfilled. For this reason, there is a possibility that trichlorophenol may flow out of the treated product, and there is a risk that dioxin may be generated from the trichlorophenol that flows out.

[0005]

In recent years, dioxin has become a problem because it has an adverse effect on the human body and the environment, and regulations on the prevention of dioxin generation have been issued. As a result of this regulation, it is no longer possible to landfill waste wood containing dioxin-containing ash or dioxin precursors. Also,
When waste wood is incinerated, dioxin is generated from organochlorine preservatives such as trichlorophenol, so that waste wood cannot be incinerated.

Further, the conventional method for thermally decomposing an organic chlorine compound requires long-term high-temperature treatment conditions as described above.

An object of the present invention is to provide a method capable of rapidly decomposing and detoxifying dioxin in incinerated ash or fly ash and organochlorine-based preservatives in rotten wood at a relatively low temperature in view of the above circumstances. It is in.

[0008]

The method for thermally decomposing an organochlorine compound according to the present invention has been devised to achieve the above-mentioned object, and comprises mixing urea into an object to be treated containing an organochlorine compound. Thereafter, the organic chlorine compound is thermally decomposed.

Representative examples of the organochlorine compounds to be treated by this thermal decomposition method include dioxin contained in ash discharged from a garbage incinerator and trichlorophenol contained in wood as a preservative. Trichlorophenol is a precursor of dioxin as described above.

As a method for mixing urea into the object containing an organic chlorine compound, an impregnation method in which the object is immersed in an aqueous urea solution is preferred.

The amount of urea mixed in the material to be treated is preferably about 3% by weight.

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

[0013]

EXAMPLES Next, examples of the present invention will be described in order to specifically explain the present invention.

Example An operation was performed using trichlorophenol, one of the harmful organic chlorine compounds contained in waste wood, in the following manner.

(I) First, 2,4,6-trichlorophenol (hereinafter abbreviated as TCP) was impregnated and supported on diatomaceous earth, which is a simulated non-treated substance, and dried to prepare an experimental sample. This sample was subjected to alcohol extraction, 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 sample was immersed in an aqueous urea solution, and the sample was impregnated with 0.075 g of urea.

(Iii) Next, the urea-impregnated sample is filled in a quartz reaction tube installed in a test tube electric furnace,
The heat treatment was performed at 300 ° C. for 30 minutes while flowing nitrogen gas through the reaction tube at a rate of 0.25 liter / min. At the outlet of the reaction tube, TCP in the outlet gas was collected by an alcohol cold trap. When the TCP concentration in the outlet gas and the residual amount of TCP in the processed sample were analyzed by the same method as described above, the TCP concentration in the outlet gas was 0.1.
004 mg / g (diatomaceous earth).
The residual amount of P was 0.013 mg / g (diatomaceous earth).

Therefore, the TCP decomposition rate is [(9.9
−0.004-0.013) /9.9] × 100 = 9
9.83%.

Comparative Example The urea impregnation treatment in step (ii) of the example was omitted, and other operations were performed in the same manner as in the example.

As a result of the analysis in step (iii), the TCP concentration in the outlet gas of the reaction tube was 10.2 mg / g (diatomaceous earth), and the residual TCP amount of the treated sample was 0.014 mg / g.
(Diatomaceous earth). The sum of the two TCPs is larger than the TCP content of the sample before the treatment, but this is considered to be due to an analysis error. In this treatment, the TCP in the sample is only volatilized in the outlet gas and no TCP decomposition occurs It was determined.

[0021]

According to the thermal decomposition method of the present invention, dioxins in incinerated ash or fly ash and organochlorine-based preservatives in decayed wood can be rapidly decomposed and made harmless at a relatively low temperature.

Therefore, by this method, waste wood containing an organic chlorine-based preservative, incinerated ash or fly ash containing dioxin can be detoxified, and these can be landfilled or reused.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Toshio Hama 5-3-28 Nishikujo, Konohana-ku, Osaka-shi Inside Tachibashi Shipbuilding Co., Ltd. (72) Toshihiko Yasuda 5-28-3, Nishikujo, Konohana-ku, Osaka-shi No. Tachi Shipbuilding Co., Ltd. (72) Inventor Kanji Ota 5-28 Nishikujo 5-chome, Konohana-ku, Osaka-shi Inside Tachibashi Shipbuilding Co., Ltd. (72) Rikio Shinohara 5-3-1 Nishikujo, Konohana-ku, Osaka-shi No. 28 Nippon Shipbuilding Co., Ltd. (72) Inventor Shoichi Tanaka 5-28 Nishikujo, Konohana-ku, Osaka City Nippon Shipbuilding Co., Ltd. (56) References JP-A-3-270719 (JP, A )

Claims (1)

(57) [Claims] 1. A method for thermally decomposing an organic chlorine compound, which comprises mixing urea into an object to be treated containing an organic chlorine compound and then thermally decomposing the organic chlorine compound.