JP2003071245A - Bag filter for removing organic chlorine compounds and its removal method - Google Patents

Abstract

(57) [Summary] [Problem] Bag filter with sufficient heat resistance 1
A bag filter for decomposing and removing organochlorine compounds having a sufficient ability to decompose organochlorine compounds at 70 to 210 ° C;
Provided is a method for removing an organic chlorine compound using the same. The above object is achieved by a bag filter for decomposition and removal of an organic chlorine compound carrying a catalyst containing chromium as a main component, and a method for removing an organic chlorine compound using the same.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filter for decomposing and removing harmful organic chlorine compounds such as dioxins contained in exhaust gas discharged from incineration facilities for treating industrial waste, municipal waste, etc. The present invention relates to a method for removing harmful organic chlorine compounds.

[0002]

2. Description of the Related Art Recently, harmful organic compounds such as dioxins generated in refuse incineration facilities have become a big social problem, and various countermeasures have been taken.

Various methods for removing this harmful organic chlorine compound have been developed, and a method for removing the organic chlorine compound using a bag filter carrying a catalyst or the like is disclosed in Japanese Patent Laid-Open Publication No. 10-187242.
No. 180039 is disclosed.

[0004]

However, since the above-mentioned bag filter has a low ability to decompose organic chlorine compounds at low temperatures, there is a problem that the organic chlorine compounds collected by the bag filter must be decomposed again. It was On the other hand, when it reaches a high temperature of about 230 ° C., it exhibits a sufficient ability to decompose the organic chlorine compound, but at this temperature, the heat resistance of the bag filter becomes a problem and it is difficult to use it for a long period of time.

It is an object of the present invention to provide a bag filter for decomposing and removing an organic chlorine compound having a sufficient heat resistance to decompose the organic chlorine compound at 170 to 210 ° C.

[0006]

As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention have found that by using a bag filter carrying a catalyst containing chromium as a main component, 170
The present inventors have completed the present invention by finding that the decomposition ability of the catalyst in the temperature range of about 210 ° C. is increased and the concentration of the organic chlorine compound on the outlet side of the bag filter can be kept low.

That is, the present invention relates to a bag filter for decomposing and removing an organic chlorine compound, which carries a catalyst containing chromium as a main component, and a method for removing an organic chlorine compound using the bag filter.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Chromium in a catalyst containing chromium as a main component is an element, salt or oxide. The catalyst may be chromium alone. Examples of components other than chromium include elements such as cerium, manganese, lanthanum, palladium and rhenium, salts and oxides, preferably at least one element selected from the group consisting of cerium, manganese and palladium. , Salt or oxide. The weight ratio of chromium to components other than chromium is about 1: 4 to 100: 1, preferably 1: 1 to 10: 1.
The degree is appropriate.

Each of the above catalysts can be supported on a carrier. Preferred carriers are titania, silica, alumina, diatomaceous earth, etc., with titania being particularly preferred. The amount of the carrier used may be about 0.5 to 100 parts by weight, usually about 1 to 20 parts by weight, relative to 1 part by weight of each of the above catalyst components.

For the production of each of the above catalysts, a general method for preparing such a catalyst can be applied. For example, as a raw material for producing a catalyst, inorganic acid salts such as nitrates, carbonates, and halides and organic acid salts such as acetates and oxalates are used as compounds of the above-mentioned respective metals. In addition, for the loading operation on the catalyst carrier, ordinary techniques such as a precipitation method, a kneading method, an impregnation method and an ion exchange method can be used. The catalyst composition thus prepared is calcined by a conventional method if necessary. The firing is preferably performed by heating in nitrogen or air at a temperature of 300 to 700 ° C. for 1 to 10 hours.

As the bag filter, a commercially available one can be used by supporting a catalyst containing chromium as a main component. For example, a non-woven fabric filter such as polyimide, polyamide, polyphenylsulfide, polytetrafluoroethylene, and polyparaphenylene benzobisoxazole excellent in heat resistance, or a woven fabric filter such as glass fiber is used. Also, 200 per 1 m ^{2 of} filter area
It is possible to support more than g catalyst and the filter thickness is 2
Those of mm or more are convenient.

The method of supporting the catalyst on the filter is most preferably a method of immersing the filter in an aqueous slurry of the catalyst, uniformly impregnating the filter with the catalyst, and then drying.
The method is not particularly limited to this.

The bag filter of the present invention can be used in any of the intermittent dust-removal method such as backwashing type and vibration type, or the continuous dust-removing method such as pulse jet, sonic jet and reverse jet.

The object of decomposition and removal by the bag filter is all organochlorine compounds, but especially polychlorinated aromatic compounds, such as 2,3,7,8-tetrachlorodibenzodioxin. Polychlorinated dibenzodioxins, represented by 2,3,4,7,8-pentachlorodibenzofuran, represented by polychlorinated dibenzofurans, 3,3 ', 4,4', 5-pentachlorobiphenyl Such polychlorinated biphenyls, chlorinated phenols represented by O-chlorophenol, chlorinated benzenes represented by chlorobenzene, and the like.

The concentration of the organochlorine compound in the gas to be treated according to the present invention is not particularly limited, and may be a saturated concentration, or may exceed the saturated concentration and be contained in the form of mist or the like. However, usually 2, 3, 7, 8-
0.01 to 5 in terms of tetrachlorodibenzodioxin
00 ng / Nm ³ or so, especially 0.05 to 10 ng / Nm ³
It is of a degree.

As the decomposition conditions, the reaction temperature is 120 to 3
The temperature is about 50 ° C., preferably about 150 to 250 ° C., particularly preferably about 170 to 210 ° C., and the linear velocity (gas supply rate in a standard state per 1 m ^{2 of} bag filter) is about 0.1 to 5 m / min. Is.

[0017]

[Example] 1. Preparation of Bag Filter for Removing Organochlorine Compound [Example] A catalyst for removing organochlorine compound (chromium + cerium + palladium / titania) was added to water in a predetermined amount to form a slurry, and an inner diameter of 20 cm and a length of 1.5 m were added to the slurry. The polyimide felt filter of was immersed in the slurry. The bag filter impregnated with the slurry was dried so that the slurry did not drip. The bag filter adjusted by this means has a filter area of 4 per 1 m ^2.
_{00g (CrO 3: CeO 2:} PdO: TiO 2 = 5.
(0: 0.5: 0.5: 94.0) catalyst was supported.

[Comparative Example] A predetermined amount of (vanadium / titania catalyst) for removing an organic chlorine compound was added to water to form a slurry, and a filter made of polyimide felt having an inner diameter of 20 cm and a length of 1.5 m was dipped in the slurry. Was impregnated. The bag filter impregnated with the slurry was dried so that the slurry did not drip. A bag filter adjusted by this means has a filter area of 425 per 1 m ^2.
g (V ₂ O ₅ : TiO ₂ = 6.0: 94.0) of the catalyst was supported.

2. Reaction Conditions and Experimental Results The above bag filters for removing organic chlorine compounds (Examples and Comparative Examples) were installed in a filter testing device, and a performance test was conducted. The reaction temperature is 170 ℃, 190 ℃, 21
The exhaust gas is set to 0 ° C and the linear velocity (LV) is 1.2 m / min.
The concentration of DXNs was measured at the inlet and outlet of the filter, converted into the toxicity equivalent conversion concentration, and the removal rate was obtained from them (Result-Table 1).

The exhaust gas is characterized by the concentration of DXNs at the inlet:
1-5 ng-TEQ / Nm ³ , soot and dust amount: 3 g / Nm ³ or less, SOx concentration: 20 ppm or less, NOx concentration: 90 p
It was pm or less and the HCl concentration was 50 ppm or less. In addition, the DXN removal rate was in accordance with the following definition. DXN removal rate (%) = ((inlet DXN concentration-outlet DX
N type concentration) ÷ Inlet DXN type concentration) x 100

[0021]

[Table 1]

[0022]

According to the present invention, the organic chlorine compound contained in the exhaust gas can be decomposed and removed at a low temperature with a high decomposition rate, and the bag filter can be stably used for a long period of time.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Tsutomu Shikata             1-2-1, Marunouchi, Chiyoda-ku, Tokyo             Main Steel Pipe Co., Ltd. (72) Inventor Yasuhiro Mogi             1-2-1, Marunouchi, Chiyoda-ku, Tokyo             Main Steel Pipe Co., Ltd. F-term (reference) 4D019 AA01 BA04 BA13 BB02 BB03                       BC07 CA04                 4D048 AA11 AB01 AB03 BA07X                       BA19X BA25X BA31X BA41X                       CD05                 4D058 JA04 NA10 TA06

Claims (2)

[Claims] 1. A bag filter for decomposing and removing an organic chlorine compound, which carries a catalyst containing chromium as a main component. 2. A gas containing an organic chlorine compound is added to 170
A method for removing an organochlorine compound, which comprises contacting the bag filter according to claim 1 at ˜210 ° C.