JP2002028447A - How to decompose organic chlorine compounds - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method capable of prolonging the life of a catalyst used for decomposing an organochlorine compound, reducing the work load and lowering the cost. The object of the present invention is to contact an exhaust gas containing an organic chlorine compound and carbonaceous fine particles with a catalyst having a function of causing the carbonaceous fine particles to burn without flame, to burn and decompose the carbonaceous fine particles, and then convert vanadium to vanadium. The problem is solved by a method for decomposing an organochlorine compound, which is characterized by contacting with a catalyst as a main component.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

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

[0003] For example, Japanese Patent Publication No. 6-38863 discloses a polyhalogenated cycloalkyl compound having 4 to 8 carbon atoms and a polyhalogenated aromatic compound having at least 5 carbon atoms by heating in the presence of a catalyst. A method for decomposing an aromatic compound, comprising: a volatile component present in a solid substrate contaminated with the polyhalogenated compound, or a liquid substrate contaminated with the polyhalogenated compound, or the polyhalogenated compound itself. The resulting gas or the gaseous substance contaminated with said polyhalogenated compound is converted to a gaseous state by heating or roasting and the catalyst is used as a catalyst in the periodic table Ia, Ib,
IIa, IIb, IIIa, IVa, IVb, VIIb or VIIIb
Using an oxide of a metal of a group III element or a mixture thereof and heating in the presence of oxygen and water in intimate contact with the catalyst, the operating temperature being 200 to 550 ° C.
A method for decomposing a polyhalogenated compound is disclosed.

[0004] Japanese Patent No. 2633316 discloses that
In an exhaust gas treatment method in which a waste incinerator exhaust gas is cooled and then dust is removed by a dust collector, and the dust-eliminated exhaust gas is brought into contact with an oxidation catalyst to decompose harmful substances in the exhaust gas. From 150 to 290
A method of decomposing at least polychlorinated dibenzodioxin and / or polychlorinated dibenzofuran in the exhaust gas by contacting a catalyst in which vanadium pentoxide and tungsten trioxide are supported on a titanium oxide carrier at a temperature of 0 ° C is disclosed. I have. In addition, a method for catalytically decomposing an organic chlorine compound using a catalyst containing vanadium as a main component is also disclosed in JP-A-8-229402.

[0005]

However, there is a problem that the life of the catalyst is short and the catalyst must be replaced frequently. This has been a major problem in that the work is complicated and costly.

An object of the present invention is to provide a method for extending the life of a catalyst used for decomposing an organochlorine compound, thereby reducing the work load and reducing the cost.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, carbonaceous fine particles contained in exhaust gas adhere to the catalyst and cover the active sites, and this causes the catalyst to become inactive. We found that it was deteriorating.

Further, they have found that a specific catalyst can efficiently burn the carbonaceous fine particles without flame.

The present invention has been made based on these findings. An exhaust gas containing an organic chlorine compound and carbonaceous fine particles is brought into contact with a catalyst having a function of causing the carbonaceous fine particles to burn without flame. The present invention relates to a method for decomposing an organic chlorine compound, which comprises decomposing carbonaceous fine particles by combustion and thereafter bringing the fine particles into contact with a catalyst containing vanadium as a main component.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION A combustion catalyst having a function of flamelessly burning carbonaceous fine particles is at least one element selected from the group consisting of platinum, iridium, rhodium, palladium, ruthenium, cerium, lanthanum, cobalt and zinc. , A salt or an oxide, preferably at least one element selected from the group consisting of platinum and cerium,
Salt or oxide. Since these combustion catalysts also have the ability to decompose the organochlorine compounds targeted by the present invention, it is possible to decompose the carbonaceous fine particles together with the organochlorine compounds adsorbed on them and convert them into carbon dioxide, water and hydrogen chloride. it can.

The catalyst containing vanadium as a main component is capable of decomposing an organochlorine compound, and may be vanadium alone. Other components than vanadium include tungsten, molybdenum, boron, manganese, chromium, lanthanum, cerium, platinum, and palladium. , Rhodium, ruthenium, at least one element selected from the group consisting of rhenium,
Salts or oxides. The ratio of vanadium to the components other than vanadium is about 1: 100 to 100: 1 by weight, preferably about 1: 5 to 5: 1.

Each of the above catalysts can be supported on a carrier. Preferred carriers are titania, silica, alumina, diatomaceous earth and the like, with titania being particularly preferred. The amount of the carrier used may be about 1 to 100 parts by weight, usually about 2 to 20 parts by weight, based on 1 part by weight of each of the above catalyst components.

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

The catalyst of the present invention can be used in any form such as a fixed bed and a moving bed. Then, if the exhaust gas is brought into contact with a combustion catalyst and then treated by contacting with a vanadium catalyst, the combustion catalyst,
A vanadium catalyst may be provided, or a combustion catalyst and a vanadium catalyst may be provided in separate catalyst reactors.

[0015] The size and shape of the catalyst are generally determined by the amount of processing gas, the concentration of dust, the method of installing the catalyst, the size of the reactor, the location of the reactor, and the like. In particular, regarding the shape, a columnar shape, a spherical shape, a honeycomb shape, a plate shape, and the like can be considered, but in the case of a gas having a high dust concentration of 0.05 g / Nm ³ or more, a honeycomb shape is preferable.

In the present invention, of the two catalysts, the combustion catalyst for burning carbonaceous fine particles is disposed on the upstream side, and the vanadium catalyst for decomposing organic chlorine compounds is disposed on the downstream side. The use ratio of the combustion catalyst to the vanadium catalyst is about 1: 100 to 100: 1, preferably about 1: 5 to 5: 1 with respect to the vanadium catalyst 1 by weight.

The catalyst of the present invention is intended to decompose organic chlorine compounds in general, but particularly to polychlorinated aromatic compounds, such as 2,3,7,8-tetrachlorodibenzodioxin. Polychlorinated dibenzodioxins, polychlorinated dibenzofurans represented by 2,3,4,7,8-pentachlorodibenzofuran, represented by 3,3 ′, 4,4 ′, 5-pentachlorobiphenyl Polychlorinated biphenyls such as O-
Chlorinated phenols represented by chlorophenol, chlorinated benzenes represented by chlorobenzene, and the like.

The concentration of the organic chlorine 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
About 00 ng / Nm ³ , particularly 0.05 to 10 ng / Nm ³
Of the degree.

As the decomposition conditions, the reaction temperature of the combustion catalyst is about 100 to 350 ° C., preferably 150 to 250 ° C.
Extent, particularly preferably at about 170 to 190 ° C., (supply rate of the gas in the standard state of the catalyst per 1 m ³⁾ space velocity is suitably about 1,000~50,000h ^-1. In the case of a vanadium catalyst, the reaction temperature is 100 to 3
At a space velocity of about 50 ° C., preferably about 150 to 250 ° C., particularly preferably about 170 to 190 ° C. (catalyst 1 m
The gas supply rate in the standard condition per ³ ) is 1,000
About ⁰ to 50,000 h ^-1 is appropriate.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Was dissolved prepared chloroplatinic acid _{(H 2 PtCl 6 · 6H 2} O) 1.3kg of catalyst having a preparation combustion function of the installation Catalyst A Preparation of a catalyst acid, the resulting aqueous solution was added to titania 20kg of powder, After kneading with a kneader, it was formed into a honeycomb shape having an outer shape of 80 mm square, an aperture of 4.0 mm, a wall thickness of 1.0 mm, and a length of 500 mm using an extruder. Then 120 ° C,
After drying for 12 hours, it was further calcined in air at 500 ° C. for 3 hours to obtain a catalyst. The component ratio (weight ratio) of the catalyst is Pt: Ti
O ₂ = 0.5: 99.5.

Preparation of a catalyst containing vanadium as a main component 1.3 kg of ammonium metavanadate (NH ₄ VO ₃ )
And ammonium paratungstate (5 (NH ₄ ) ₂ O.
12WO ₃ · 5H ₂ O) 1.1kg was heated to 80 ° C. 1
The resulting solution was dissolved in a 0% by weight aqueous monoethanolamine solution, and the resulting solution was added to 18 kg of powdered titania, kneaded with a kneader, and then extruded with an extruder to have an outer shape of 80 mm square, an aperture of 4.0 mm, a wall thickness of 1.0 mm, and a length of 1.0 mm. It was formed into a honeycomb shape having a thickness of 500 mm. Next, after drying at 120 ° C. for 12 hours, it was further calcined in air at 500 ° C. for 3 hours to obtain a catalyst. The component ratio (weight ratio) of the catalyst is V ₂ O ₅ : WO ₃ : TiO ₂ = 5.
0: 5.0: 90.0.

Installation of Catalyst A platinum catalyst having a catalytic combustion function was installed in series on the exhaust gas inlet side of the catalytic reactor, and a catalyst containing vanadium as a main component was installed in series on the exhaust gas outlet side.

Preparation of Catalyst B Preparation of Catalyst Having Combustion Function Rhodium chloride trihydrate (RhCl ₃ .3H ₂ O) 1.3 k
g was dissolved in distilled water, and the obtained aqueous solution was added to 20 kg of powdered titania, kneaded with a kneader, and then extruded with an extruder to have an outer shape of 80 mm square, an aperture of 4.0 mm, and a wall thickness of 1.0 kg.
mm and a length of 500 mm. Then, after drying at 120 ° C. for 12 hours, it is further dried at 500 ° C.
After calcination for an hour, a catalyst was obtained. The component ratio (weight ratio) of the catalyst was Rh: TiO ₂ = 0.5: 99.5.

Preparation of a catalyst containing vanadium as a main component 1.3 kg of ammonium metavanadate (NH ₄ VO ₃ )
And ammonium paratungstate (5 (NH ₄ ) ₂ O.
12WO ₃ · 5H ₂ O) 1.1kg was heated to 80 ° C. 1
The resulting solution was dissolved in a 0% by weight aqueous monoethanolamine solution, and the resulting solution was added to 18 kg of powdered titania, kneaded with a kneader, and then extruded with an extruder to have an outer shape of 80 mm square, an aperture of 4.0 mm, a wall thickness of 1.0 mm, and a length of 1.0 mm. It was formed into a honeycomb shape having a thickness of 500 mm. Next, after drying at 120 ° C. for 12 hours, it was further calcined in air at 500 ° C. for 3 hours to obtain a catalyst. The component ratio (weight ratio) of the catalyst is V ₂ O ₅ : WO ₃ : TiO ₂ = 5.
0: 5.0: 90.0.

Installation of Catalyst A rhodium catalyst having a catalytic combustion function was installed in series on the exhaust gas inlet side of the catalytic reactor, and a catalyst containing vanadium as a main component was installed in series on the exhaust gas outlet side.

Preparation of Catalyst C Preparation of Catalyst Having Combustion Function Ruthenium Chloride Trihydrate (RuCl ₃ .3H ₂ O) 0.2
6 kg was dissolved in distilled water, and the obtained aqueous solution was added to 20 kg of powdered titania, kneaded with a kneader, and then extruded with an extruder to have an outer shape of 80 mm square, an opening of 4.0 mm, a wall thickness of 1.0 mm, and a length of 500 mm. Into a honeycomb shape.
Then, after drying at 120 ° C. for 12 hours, it is further dried in air for 500 hours.
C. for 3 hours to obtain a catalyst. The component ratio (weight ratio) of the catalyst was Ru: TiO ₂ = 0.5: 99.5.

Preparation of Vanadium-based Catalyst 1.3 kg of ammonium metavanadate (NH ₄ VO ₃ )
And ammonium paratungstate (5 (NH ₄ ) ₂ O.
12WO ₃ · 5H ₂ O) 1.1kg was heated to 80 ° C. 1
The resulting solution was dissolved in a 0% by weight aqueous monoethanolamine solution, and the resulting solution was added to 18 kg of powdered titania, kneaded with a kneader, and then extruded with an extruder to have an outer shape of 80 mm square, an aperture of 4.0 mm, a wall thickness of 1.0 mm, and a length of 1.0 mm. It was formed into a honeycomb shape having a thickness of 500 mm. Next, after drying at 120 ° C. for 12 hours, it was further calcined in air at 500 ° C. for 3 hours to obtain a catalyst. The component ratio (weight ratio) of the catalyst is V ₂ O ₅ : WO ₃ : TiO ₂ = 5.
0: 5.0: 90.0.

Installation of Catalyst A ruthenium catalyst having a catalytic combustion function was installed in series on the exhaust gas inlet side of the catalytic reactor, and a catalyst containing vanadium as a main component was installed in series on the exhaust gas outlet side.

Preparation of Catalyst D Preparation of Catalyst Having Combustion Function Cerium nitrate hexahydrate (Ce (NO ₃ ) ₂ .6H ₂ O)
2.5 kg was dissolved in distilled water, and the obtained aqueous solution was added to 19 kg of powdered titania, kneaded with a kneader, and then extruded with an extruder to have an outer shape of 80 mm square, an aperture of 4.0 mm, a thickness of 1.0 mm, and a length of 1.0 mm. It was formed into a honeycomb shape having a thickness of 500 mm. Then, after drying at 120 ° C. for 12 hours, the mixture was further dried in air for 5 hours.
It was calcined at 00 ° C. for 3 hours to obtain a catalyst. The component ratio (weight ratio) of the catalyst was CeO ₂ : TiO ₂ = 5.0: 95.0.

Preparation of a catalyst containing vanadium as a main component 1.3 kg of ammonium metavanadate (NH ₄ VO ₃ )
And ammonium paratungstate (5 (NH ₄ ) ₂ O.
12WO ₃ · 5H ₂ O) 1.1kg was heated to 80 ° C. 1
The resulting solution was dissolved in a 0% by weight aqueous monoethanolamine solution, and the resulting solution was added to 18 kg of powdered titania, kneaded with a kneader, and then extruded with an extruder to have an outer shape of 80 mm square, an aperture of 4.0 mm, a wall thickness of 1.0 mm, and a length of 1.0 mm. It was formed into a honeycomb shape having a thickness of 500 mm. Next, after drying at 120 ° C. for 12 hours, it was further calcined in air at 500 ° C. for 3 hours to obtain a catalyst. The component ratio (weight ratio) of the catalyst is V ₂ O ₅ : WO ₃ : TiO ₂ = 5.
0: 5.0: 90.0.

Installation of Catalyst A cerium catalyst having a catalytic combustion function was installed in series on the exhaust gas inlet side of the catalytic reactor, and a catalyst containing vanadium as a main component was installed in series on the exhaust gas outlet side.

Comparative Example 2.6 kg of ammonium metavanadate (NH ₄ VO ₃ )
And ammonium paratungstate (5 (NH ₄ ) ₂ O.
12WO ₃ · 5H ₂ O) 2.3kg was heated to 80 ° C. 1
Dissolved in a 0% by weight aqueous monoethanolamine solution, and the resulting solution was added to 36 kg of powdered titania, kneaded with a kneader, and then extruded with an extruder to have an outer shape of 80 mm square and openings of 4.
It was formed into a honeycomb shape having a thickness of 0 mm, a thickness of 1.0 mm, and a length of 1000 mm. Next, after drying at 120 ° C. for 12 hours, it was further calcined in air at 500 ° C. for 3 hours to obtain a catalyst. The component ratio (weight ratio) of the catalyst is V ₂ O ₅ : WO ₃ : TiO ₂ = 5.
0: 5.0: 90.0.

Installation of Catalyst The above catalyst was installed in a catalytic reactor.

2. Reaction conditions and experimental results The above catalyst was packed in a fixed-bed flow catalyst reactor under normal pressure, and an activity test of the catalyst was performed. The reaction tube was heated to a reaction temperature of 18
Set to 0 ° C, and waste incineration exhaust gas with a space velocity (SV) of 5,0
The concentration of DXNs was measured at the inlet and the outlet of the catalyst layer at 1 hour and 1,000 hours after the start of the reaction, and was converted to a toxic equivalent concentration, and the removal rate was calculated therefrom (00h ^-1 ). Results-Table 1).

The properties of the garbage incineration exhaust gas are as follows:
0.03 g / Nm ³ or less, SOx concentration: 30 ppm or less, NOx concentration: 80 ppm or less, HCl concentration: 50 p
pm or less, dioxin concentration: 1.05 ng-TEQ
/ Nm ³ . In addition, the DXN removal rate was in accordance with the following definition. DXN removal rate (%) = ((inlet DXN concentration-outlet D)
XNs concentration) ÷ Inlet DXNs concentration) × 100

[0036]

[Table 1]

[0037]

According to the method of the present invention, by installing a catalyst having a catalytic combustion function in series at the exhaust gas inlet side of the reactor and a catalyst mainly composed of vanadium at the exhaust gas outlet side,
Unburned particulate matter such as hydrocarbons is efficiently burned and decomposed by the catalyst at the former stage, catalyst deterioration is reduced, and organic chlorine compounds in exhaust gas can be decomposed and removed efficiently for a long period of time.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) B01J 23/46 301 C07B 35/06 311 37/06 C07B 35/06 C07C 25/02 37/06 25/18 C07C 25/02 39/28 25/18 C07D 319/24 39/28 B01D 53/36 ZABG C07D 319/24 103C (72) Inventor: Tsutomu Shida 1-1-2 Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Inventor Yasuhiro Mogi 1-2-1, Marunouchi, Chiyoda-ku, Tokyo F-term (reference) 4D048 AA11 AA14 AB01 AB03 BA04Y BA07X BA13X BA16Y BA18Y BA19X BA23X BA27X BA30X BA31Y BA32X BA33X BA37Y BA42X CC38 CC46 4G069 AA02 AA03 BA04A BA04B BB02A BB02B BB06A BB06B BC35A BC42A BC43A BC43B BC50A BC50B BC54A BC54B BC58A BC59A BC60A BC60B BC62A BC64A BC67A BC7 0A BC70B BC71A BC71B BC72A BC75A BC75B BD03A CA04 CA07 CA10 CA11 CA18 CA19 EA19 EB14Y EB15Y EB17Y EE09 4H006 AA05 AC13 AC26 BA10 BA12 BA14 BA30 BD60 BD70

Claims (1)

[Claims] 1. An exhaust gas containing an organic chlorine compound and carbonaceous fine particles is brought into contact with a catalyst having a function of causing the carbonaceous fine particles to burn without flame, and the carbonaceous fine particles are burned and decomposed. A method for decomposing an organochlorine compound, which is brought into contact with a catalyzing catalyst