JP2002370015A - Composite catalyst for decomposing organohalogen compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composite catalyst capable of efficiently decomposing dioxins and an aliphatic organohalogen compound becoming a precursor of dioxins such as an aromatic organohalogen compound, trichloroethylene, dichloromethane or the like discharged from a refuse incinerator or the like. SOLUTION: The composite catalyst for decomposing the organohalogen compound is obtained by supporting a compound of at least one kind of a transition metal selected from Ni, Mn, Co, Zr and V on the surface of a hydrated iron oxide powder having a mean particle size of 0.01-2.0 μm and containing 0.02 wt.% or less phosphorus, 0.3 wt.% or less of sulfur and 0.3 wt.% or less of sodium or the surfaces of iron oxide particles in an amount of 1-30 mol% with respect to Fe.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a process for efficiently decomposing dioxins discharged from refuse incinerators and the like, aromatic organic halogen compounds as precursors thereof, and aliphatic organic halogen compounds such as trichloroethylene and dichloromethane. It is intended to provide a catalyst which can be used.

[0002]

2. Description of the Related Art Exhaust gas generated from refuse incinerators for incinerating municipal and industrial wastes contains a small amount of dioxins which are extremely toxic to the human body. Note that dioxins are a general term for compounds in which hydrogen is replaced with chlorine, such as dibenzo-p-dioxin and dibenzofuran.

[0003] Further, aliphatic organic halogen compounds such as trichloroethylene and tetrachloroethylene are widely used for degreasing metals and dry cleaning.

Since these organic halogen compounds are hardly decomposable and are carcinogenic substances, environmental pollution due to discharge into the air or elution into groundwater or soil has become a problem. Various methods have been proposed for treating compounds, but economical and efficient decomposition / detoxification techniques have not yet been sufficiently established.

Heretofore, techniques for decomposing organic halogen compounds using catalysts comprising various metal compounds have been attempted (Japanese Patent Publication No. 6-38863, Japanese Patent Application Laid-Open No. 2-2808).
No. 16, JP-A-3-47516, JP-A-3-11
-226,972, JP-A-11-188235, JP-A-2000-135439 and JP-A-200
0-167406).

Further, as a method of incinerating the waste in advance by mixing it with iron oxide or the like, the combustible waste is heated at a temperature of 850 ° C. or more in the presence of an acid gas neutralizer and iron oxide particles. Method for burning combustible waste to be burned
No. 70924), and an incineration method in which incinerated ferric oxide particles or iron oxide particles having a sulfur and sodium content of not more than predetermined amounts and an incineration material coexist in a combustion furnace and burn (Japanese Patent Application Laid-Open No. 9-89228). Gazette) has been attempted.

[0007]

At present, there is a demand for a treatment method capable of decomposing and removing an organic halogen compound contained in exhaust gas or the like, but the methods described in the above-mentioned publications are still insufficient. Is hard to say.

In the method described in Japanese Patent Publication No. 6-38863, a polyhalogenated aromatic compound having at least 5 or more carbon atoms is decomposed by heating at 200 to 550 ° C. in the presence of a catalyst such as iron oxide. And a method in which fly ash generated in an incinerator is used to decompose a polyhalogenated cycloalkyl compound or a polyhalogenated aromatic compound by a catalyst such as iron oxide, calcium carbonate, or sodium carbonate in a fixed bed. However, it is difficult to sufficiently remove the organic halogen compound, and constructing such a fly ash detoxification facility requires enormous capital investment.

[0009] The method described in Japanese Patent Application Laid-Open No. 2-280816 discloses a method in which an exhaust gas is subjected to 300-70 in the presence of a catalyst containing iron oxide.
In order to remove or reduce the halogenated aromatic compound by heat treatment at a temperature of 0 ° C., ammonia is added to the exhaust gas containing the halogenated aromatic compound, and the halogenated aromatic compound is added by a catalyst containing iron oxide in a fixed bed. It decomposes group compounds and constructing such a facility at a later stage such as a refuse incinerator requires enormous capital investment.

The method described in JP-A-3-47516 is a method in which a metal compound such as cobalt or copper is supported on zeolite or silica or the like and decomposed by contacting an organic halogen compound, and has a relatively small molecular weight. It is intended for organic halogen compounds and is not suitable for decomposing organic halogen compounds having a large molecular weight such as aromatic halogen compounds.

The method described in Japanese Patent Application Laid-Open No. H11-226397 uses an activated carbon carrying a metal or a metal oxide having an oxidizing ability such as vanadium or iron.
It removes dioxins in the exhaust gas at 220 ° C and decomposes the organic halogen compound adsorbed on the activated carbon, but when the residence time in the exhaust gas is short, the organic halogen compound remains undecomposed. Since the dust is collected as it is, a secondary treatment of the dust ash is required.

In the method described in JP-A-11-188235, an organic halogen compound in exhaust gas is decomposed at 60 to less than 150 ° C. in the presence of oxygen using a solid catalyst based on iron oxide or the like and / or titanium dioxide. The organic halogen compound is decomposed at a low temperature, but the decomposition rate is low and is not practical.

Japanese Patent Application Laid-Open No. 2000-135439 discloses C
Japanese Patent Application Laid-Open No. 2000-167406 describes that a ternary composite oxide composed of one selected from o, Cr, Cu, Ce, Ni, Sn, and V and Mn and Fe is used as a dioxin remover. Describes that a composite oxide using Mn and Fe as a base is used as a dioxin removing agent, but none of them has a sufficient dioxin removal rate.

The methods described in JP-A-8-270924 and JP-A-9-89228 are difficult to perform simply because it is necessary to sufficiently mix the iron oxide with the waste in advance.

[0015] In the incineration method using iron oxide hydroxide particles or iron oxide particles having a sulfur and sodium content of not more than predetermined amounts (Japanese Patent Application Laid-Open No. 9-89228), 3
Since the decomposition rate of monochlorobenzene at 00 ° C. was low, it was insufficient to decompose organic halogen compounds such as dioxin.

Accordingly, the present invention is intended to economically and efficiently decompose dioxins discharged from refuse incinerators and the like, aromatic organic halogen compounds as precursors thereof, and aliphatic organic halogen compounds such as trichloroethylene and dichloromethane. It is a technical object to provide a catalyst that can be treated.

[0017]

The above technical object can be achieved by the present invention as described below.

That is, the present invention provides an average particle diameter of 0.01 to
2.0 μm and a phosphorus content of 0.02% by weight or less,
Ni, Mn, Co, Zr and V are formed on the surface of each of the iron oxide hydrate particles or the iron oxide particles having a sulfur content of 0.3% by weight or less and a sodium content of 0.3% by weight or less.
A composite catalyst for decomposing an organic halogen compound, wherein 1 to 30 mol% of at least one transition metal compound selected from the group consisting of:

Further, the present invention is a composite catalyst for decomposing an organic halogen compound, wherein the composite catalyst for decomposing an organic halogen compound carries 0.01 to 10% by weight of an amine compound.

The structure of the present invention will be described in detail as follows.

First, the composite catalyst for decomposing an organic halogen compound according to the present invention will be described.

The hydrous iron oxide particles used in the composite catalyst for decomposing an organic halogen compound according to the present invention are goethite, akagenite, lepidocrocite and the like, and the iron oxide particles are hematite, maghemite, magnetite and the like. Goethite, hematite, and magnetite are preferred, and goethite or hematite is more preferred. Hereinafter, the term “iron compound particle powder” will be used when the iron oxide-containing particles and the iron oxide particles are collectively referred to.

The particle shape of the iron compound particles in the present invention may be any of spherical particles, granular particles, octahedral particles, hexahedral particles, polyhedral particles, etc., and acicular particles such as needles, spindles, rice grains and the like. It may be spindle-shaped or needle-shaped.

The average particle diameter of the iron compound particles in the present invention is 0.01 to 2.0 μm, preferably 0.02 to 2.0 μm.
It is 2.0 μm, more preferably 0.02 to 1.0 μm.

The iron compound particles according to the present invention have a phosphorus content of 0.02% by weight or less, preferably 0.01% by weight or less, more preferably 0.005% by weight or less.
If it exceeds 0.02% by weight, the phosphorus acts as a catalyst poison, so that the decomposition activity of the organic halogen compound is reduced.

The iron compound particles according to the present invention have a sulfur content of 0.3% by weight or less, preferably 0.1% by weight or less, more preferably 0.07% by weight or less. 0.3
If the content exceeds 10% by weight, the sulfur acts as a catalyst poison, so that the decomposition activity of the organic halogen compound is reduced.

The iron compound particles according to the present invention have a sodium content of 0.3% by weight or less, preferably 0.2% by weight or less, more preferably 0.15% by weight or less.
If it exceeds 0.3% by weight, the sodium acts as a catalyst poison, so that the decomposition activity of the organic halogen compound is reduced.

The iron compound particles according to the present invention,
The total content of sulfur compounds and sodium is 0.5% by weight
It is preferably at most 0.3% by weight, more preferably at most 0.2% by weight. If it exceeds 0.5% by weight, the decomposition activity of the organic halogen compound is reduced.

BET of iron compound particles in the present invention
The specific surface area is preferably 0.2~200m ² / g, more preferably 1.0~200m ² / g, most preferably 2.0~150m ² / g.

The iron compound particle powder of the present invention is obtained by subjecting 50 mg of the composite catalyst powder obtained by heat treatment at 300 ° C. for 60 minutes in air to a pulse type catalytic reactor.
5.0 × 1 in an inert gas atmosphere at a temperature of 300 ° C.
^0-7 mol of monochlorobenzene and SV = 1500
It is preferable that the monochlorobenzene has an activity capable of decomposing 20% or more of the monochlorobenzene and converting 4% or more of the monochlorobenzene to carbon dioxide when it is contacted instantaneously under the condition of 00h- ¹ .

Incidentally, monochlorobenzene is a typical organic halogen compound, and is considered to be a precursor of dioxins. Having the activity of decomposing monochlorobenzene is required for organic halogen compounds such as dioxins. It serves as an indicator of having a decomposing activity. The decomposition rate of monochlorobenzene is a value shown by the following equation (1).

[0032]

## EQU1 ## Monochlorobenzene decomposition rate [%] = [1- (detected amount of monochlorobenzene after reaction / injected amount of monochlorobenzene before reaction)] × 100

The particle shape and particle size of the composite catalyst for decomposing an organic halogen compound according to the present invention are substantially the same as the particle shape and particle size of the iron compound particles.

The average particle size of the composite catalyst for decomposing an organic halogen compound according to the present invention is preferably 0.01 to 2.0 μm, more preferably 0.02 to 2.0 μm, and most preferably 0.02 to 1.0 μm. It is.

When the average particle diameter of the composite catalyst for decomposing an organic halogen compound according to the present invention is more than 2.0 μm, the contact efficiency with the organic halogen compound is reduced, and sufficient organic halogen compound decomposing activity is not exhibited. When the particle size is 0.01 μm or less, the particle size becomes larger due to the influence of sintering or the like, and thus the decomposition activity of the organic halogen compound is reduced.

The composite catalyst for decomposing an organic halogen compound according to the present invention is characterized in that Ni, Mn, Co,
One or more transition metal compounds selected from Zr and V
1 to 30 mol% is supported on e. When the amount of the transition metal compound supported is less than 1 mol%, the improvement in the decomposition activity of the organic halogen compound by the transition metal is small. If it exceeds 30 mol%, the effect is saturated, and it is meaningless to carry more than necessary. The loading amount of the transition metal compound is preferably 1 to 25 mol%, more preferably 1 to 25 mol%.
~ 20 mol%. On the other hand, in the case of the composite catalyst in which the transition metal is dissolved, the decomposition activity is lower than in the case where the transition metal compound is supported on the particle surfaces of the iron compound particles.

[0037] BET specific surface area of the organic halogen compound-decomposing composite catalyst according to the present invention is preferably 0.2~200m ² / g, more preferably 1.0~200m ² / g, most preferably 2.0 to 150 m ² / g.

In the composite catalyst for decomposing an organic halogen compound according to the present invention, the phosphorus content, the sulfur content and the sodium content are substantially the same as those of the iron compound particles.

The composite catalyst for decomposing an organohalogen compound according to the present invention, when it is brought into contact with monochlorobenzene instantaneously in the same manner as described above, is 40% of the monochlorobenzene.
It is preferable to have an activity capable of decomposing the above and converting 15% or more to carbon dioxide. More preferably,
Monochlorobenzene has a decomposition activity of 45% or more, and a conversion activity to carbon dioxide is 20% or more.

When the activity of decomposing monochlorobenzene is less than 40% or the activity of converting carbon dioxide to carbon dioxide is less than 15%, the effect of the present invention cannot be obtained.

An amine compound can be supported on the composite catalyst for decomposing an organic halogen compound according to the present invention, if necessary. By supporting an amine compound, dioxins are easily adsorbed, and the decomposition efficiency is improved.

As the amine compound in the present invention, one or more of alkylamines such as diethylenetriamine and triethylenetetramine, alkanolamines such as triethanolamine and diethanolamine, and cyclic amines such as aniline can be used. .

The amine compound in the present invention preferably has a boiling point of 150 ° C. or higher. If the boiling point is less than 150 ° C., the organic compound is easily volatilized during the treatment with the organic halogen compound, and the effect of supporting the compound cannot be obtained.

The loading amount of the amine compound in the present invention is preferably 0.01 to 10% by weight, more preferably 0.05 to 8% by weight, and most preferably 0.1 to 5% by weight.
It is. When the content is 0.01% by weight or less, the effect of promoting the decomposition of the organic halogen compound is small, and when it exceeds 10% by weight, the decomposition activity of the composite catalyst for decomposing an organic halogen compound according to the present invention itself is reduced.

The composite catalyst for decomposing an organic halogen compound supporting an amine compound according to the present invention is obtained by
50 mg of the composite catalyst powder heat-treated at 60 ° C. for 60 minutes,
When a pulse-type catalytic reactor is used to instantaneously contact 5.0 × 10 ⁻⁷ mol of monochlorobenzene in an inert gas atmosphere at a temperature of 300 ° C. under the condition of SV = 150,000 h ^−1. , 60 of the monochlorobenzene
% Or more, and preferably has an activity of converting 15% or more to carbon dioxide, more preferably 65% or more of monochlorobenzene decomposition activity and 20% or more of conversion activity to carbon dioxide.

Next, a method for producing the composite catalyst for decomposing an organic halogen compound according to the present invention will be described.

First, the method for producing the iron compound particles according to the present invention will be described.

The iron compound particles in the present invention are particles obtained by a known method, and the goethite particles are, for example, one or two selected from ferrous salts and alkali hydroxides, alkali carbonates or ammonia. It can be obtained by passing an oxygen-containing gas such as air through a suspension containing a precipitate containing ferrous iron or the like, such as iron hydroxide or iron carbonate, which is obtained by reacting with at least one species.

The hematite particle powder can be obtained, for example, by subjecting the goethite particle powder to heat dehydration in the temperature range of 200 to 800 ° C. in the air. It can be obtained by heating and reducing at 300 to 600 ° C. in an atmosphere. The maghemite particle powder can be obtained, for example, by heating and oxidizing the magnetite particle powder in air at 200 to 600 ° C.

In the production of the iron compound particles according to the present invention, it is preferable that the contents of phosphorus, sulfur and sodium, which are poisons of the catalyst, are not more than the above-mentioned predetermined amounts. Specifically, the ferrous salt solution preferably has a low content of phosphorus, sulfur and the like, which are poisons for the catalyst. Also,
Normally, without using sodium hexametaphosphate used for sintering prevention treatment at the time of heating and firing, sulfate ions derived from ferrous raw materials and sodium ions derived from alkalis are subjected to purification treatment such as sufficient washing with water. Rin,
It is preferable to reduce the contents of sulfur and sodium.

The composite catalyst for decomposing an organohalogen compound according to the present invention can be prepared by an impregnation method in which a transition metal salt solution is impregnated into iron compound particles, or by adding a transition metal salt to a slurry containing iron compound particles, and mixing and stirring. By adjusting the pH value with an alkali or the like as necessary, a coating method of coating the surface of the iron compound particles with a hydroxide of a transition metal can be used. In the impregnation method, it is preferable that after the impregnation, a drying treatment is performed, and if necessary, a further heat treatment is performed, followed by pulverization. In the coating method, after coating, filtration,
After performing the drying treatment and, if necessary, further performing the heating treatment,
Pulverization is preferred.

By the complexing treatment, the transition metal hydroxide and / or oxide fine particles can be uniformly supported on the iron compound particles.

In the compounding of the iron compound particles and the transition metal compound in the present invention, it is preferable that the contents of phosphorus, sulfur and sodium, which are poisons of the catalyst, are not more than a predetermined amount. As the transition metal salt,
It is preferable to use a catalyst having a low content of sulfur or the like which is a catalyst poison. Further, in the coating method, it is preferable to reduce the contents of phosphorus, sulfur and sodium by performing purification treatment such as sufficient washing with water for sulfate ions derived from transition metal salts and sodium ions derived from alkali. .

Next, a method for supporting a composite catalyst for decomposing an organic halogen compound which supports an amine compound according to the present invention will be described.

The supporting by the amine compound is carried out by a dry method such as a sand mill, a Henschel mixer and a Nauter mixer, wherein the composite catalyst for decomposing an organic halogen compound according to the present invention and the amine compound or an amine compound solution dissolved in a solvent such as water or alcohol are used. A method of mixing using a mixer, a dipping method of dipping the composite catalyst for decomposing an organic halogen compound according to the present invention in the amine compound solution, or the like can be used. In any method, when a solvent is used, it is desirable to evaporate the solvent under heating or reduced pressure.

Next, a method for treating an organic halogen compound using the composite catalyst for decomposing an organic halogen compound according to the present invention will be described.

The gas or solid containing an organic halogen compound is treated by bringing it into contact with the composite catalyst for decomposing an organic halogen compound according to the present invention. The treatment temperature is preferably from 150 to 600 ° C, more preferably from 200 to 600 ° C. 150 ° C
If it is less than 1, the decomposition activity of the composite catalyst for decomposing an organic halogen compound according to the present invention is low, and if it exceeds 600 ° C, the composite catalyst for decomposing an organic halogen compound according to the present invention is thermally degraded, and the decomposition activity is lowered.

Examples of the method of contacting with a gas containing an organic halogen compound include a method of adding a powdery or slurry-like composite catalyst for decomposing an organic halogen compound according to the present invention to a gas containing an organic halogen compound by a pneumatic conveying method. There is a method in which a pellet-shaped composite catalyst for decomposing an organic halogen compound according to the present invention is filled in a catalytic reactor such as a fixed bed or a fluidized bed, and a gas containing an organic halogen compound is passed.

As a method of contacting with a solid containing an organic halogen compound, there is a method in which a solid containing an organic halogen compound and the composite catalyst for decomposing an organic halogen compound according to the present invention are mixed in a dry mixer in advance and then heat-treated. is there.

By the decomposition treatment of the organic halogen compound using the composite catalyst for decomposing an organic halogen compound according to the present invention, for example, dioxin in the exhaust gas at the outlet of the dust collector in a garbage incineration facility of an electric dust collector system is obtained by: 0ng
TEQ / Nm ³ or less, preferably 1.5 ng TEQ / N
m ³ can be below.

[0061]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A typical embodiment of the present invention is as follows.

The average particle diameter of the composite catalyst for decomposing an organic halogen compound according to the present invention was shown by the average value of the values measured from an electron micrograph. The specific surface area was indicated by a value measured by the BET method.

The content of phosphorus and sodium contained in the composite catalyst for decomposing an organic halogen compound according to the present invention is determined by the inductively coupled plasma atomic emission spectrophotometer SPS-400.
0 "(manufactured by Seiko Denshi Kogyo KK).

The content of sulfur contained in the composite catalyst for decomposing an organic halogen compound according to the present invention is shown by a value measured by a “carbon-sulfur analyzer EMIA-2200” (manufactured by HORIBA, Ltd.). .

The catalytic characteristics of the composite catalyst for decomposing an organic halogen compound according to the present invention are as follows. 50 mg of the composite catalyst heat-treated in air at 300 ° C. for 60 minutes is measured at a temperature of 300 ° C. using a pulse type catalytic reactor. 5.0 × 10 ⁻⁷ mol of monochlorobenzene and SV = in an inert gas atmosphere
It was evaluated by measuring the amount of monochlorobenzene which decomposes when contacted instantaneously under the condition of 150,000 h ^{-1 and} the amount of carbon dioxide obtained by conversion.

The catalytic properties of the composite catalyst for decomposing an organic halogen compound carrying an amine compound according to the present invention were also evaluated by measuring the same in the same manner as described above.

The above-mentioned pulse type catalytic reactor comprises a reactor section and a gas chromatography mass spectrometer section, and the gas chromatography mass spectrometer section is composed of “gas chromatography mass spectrometer GC / MSQP-5050”.
(Manufactured by Shimadzu Corporation).

The method for evaluating the above-mentioned catalyst characteristics is described in Kobe
et al. (RJ Kobes, et al JA).
m. Chem. Soc. , 77, 5860 (195)
5)) and “Reaction and Rate of Experimental Chemistry Lecture 11” edited by The Chemical Society of Japan (Maruzen, Tokyo (1993)).

<Iron Compound Particle Powder> As iron compound particle powder, goethite particle powder (particle shape: spindle shape, average particle size 0.25 μm, phosphorus content 0.005% by weight, sulfur content 0.05% by weight, A sodium content of 0.10% by weight and a BET specific surface area of 85 m ² / g) were used.

According to the evaluation method, the goethite particle powder has a decomposition rate of monochlorobenzene of 25%,
The conversion to carbon dioxide was 6%.

<Production of Composite Catalyst> 1.5 kg of the goethite particle powder and 1.5 l of water were mixed in a double-arm kneader at room temperature for 10 minutes to form a paste, and the nitrate of Co was added to the paste. It was added so as to be 1 mol% with respect to the iron element in the particle powder, followed by mixing at room temperature for 20 minutes in a double-arm kneader, followed by drying at 70 ° C all day and night, and then at 300 ° C for 60 minutes. After the heat treatment, pulverization was performed to obtain a composite catalyst for decomposing an organic halogen compound according to the present invention.

The composite catalyst obtained here was spindle-shaped particles having an average particle diameter of 0.25 μm, the supported amount of cobalt was 1.0 mol% with respect to Fe, and the phosphorus content was 0.00
5% by weight, sulfur content 0.05% by weight, sodium content 0.10% by weight, and a BET specific surface area of 120 m
A ² / g, the decomposition rate of monochlorobenzene at 300 ° C. is 60%, conversion of carbon dioxide was 24%.

<Dioxin Decomposition Test> FIG. 1 is a schematic diagram of the intermittently operating waste incineration facility used in this test. In the figure, 1 is a waste hopper, 2 is an incinerator, 3 is a combustion chamber,
4 is an auxiliary burner port, 5 is a gas cooling chamber, 6 is an air preheater,
7 is a blower for supplying a composite catalyst for decomposing an organic halogen compound,
8 is a supply tank for a composite catalyst for decomposing an organic halogen compound,
9 is an electric dust collector, 10 is an induction blower, 11 is a chimney, 1
Reference numeral 2 denotes a forced air blower, 13 denotes a flue, and 14 to 17 denote supply ports for a composite catalyst for decomposing an organic halogen compound.

The combustion chamber 3 is supplied with combustion air from the hearth of an incinerator, which is about 1.5 to 3.5 times the theoretical air amount required for complete combustion of the refuse. As the combustion air, air is sucked in by a forced air blower 12 and air heated by an air preheater 6 is used. The combustion chamber 3 is provided with an auxiliary burner port 4. The composite catalyst for decomposing an organic halogen compound and the acid gas neutralizer (eg, slaked lime) according to the present invention are supplied to the supply
To 17 and so on.

The intermittent operation type waste incineration facility (16 per day)
At hourly operation, the incineration capacity is 30 tons / day, and 0.25% by weight of the obtained composite catalyst for decomposing an organic halogen compound according to the present invention is supplied to the supply port 16 (exhaust gas temperature) by pneumatic transportation with respect to dry waste. 262 ° C.), and spray-added for 16 hours from the start-up of the incinerator to the steady operation and the start-up. Also, 0.50% by weight of slaked lime powder based on dry garbage (JIS special name, manufactured by Ube Materials Co., Ltd., average particle size D ₅₀ 5.7 μm, BET specific surface area 13.7 m ²⁾
/ G) by pneumatic transport from the supply port 17 in the same manner as above for 16 hours from the start-up of the incinerator to the steady operation and the start-up of the incinerator (total of the composite catalyst for decomposing an organic halogen compound and slaked lime, 0.75% by weight based on refuse).

The dioxin content was measured on the exhaust gas collected at the outlet of the electrostatic precipitator 9 and on fly ash under the electric precipitator. The measurement and analysis of dioxins were carried out in accordance with the "Standard Manual for Analysis and Measurement of Dioxins in Waste Disposal" (established in February 1997 by the Ministry of Health and Welfare, Health and Welfare Bureau, Water Supply Environment Department, Environment Improvement Section).

Dioxy in exhaust gas at the outlet of an electrostatic precipitator
Concentration is 0.63 ng TEQ / Nm ³And electricity collection
The dioxin concentration in the fly ash collected by the sprayer is 2.
It was 4 ng TEQ / g.

As a blank test, the operation of the incinerator when the goethite particle powder and slaked lime were added,
The operation of the incinerator when only slaked lime was added was performed in the same manner, and the dioxin concentrations in the exhaust gas and fly ash at the outlet of the electric precipitator were measured.

The dioxin concentration in the exhaust gas at the outlet of the electrostatic precipitator is 2.
0ngTEQ / Nm ³ , 1 when only slaked lime is added
It was 5ngTEQ / Nm ^3. The dioxin concentration in fly ash collected by the electrostatic precipitator was 6.3 ng TEQ / g when goethite particles were added, and 22 ng TEQ / g when only slaked lime was added.

[0080]

An important point of the present invention is that the organic halogen compound can be decomposed effectively by using the composite catalyst for decomposing an organic halogen compound according to the present invention.

The present inventor believes that the reason why the organic halide compound can be decomposed effectively is that the iron compound particle powder itself has an excellent ability to oxidize the organic halogen compound, and the transition metal supported on the surface of the iron compound particle powder. It is considered that the organic halogen compound could be effectively decomposed by the fact that the reaction rate of the oxidative decomposition reaction was increased by the compound fine particles and that the iron compound particle powder was in contact with the transition metal compound.

When the amine compound is carried, the adsorption reaction of the organic halogen compound is promoted by the carried amine compound, and the iron compound particle powder and the amine compound are in contact with each other. It is considered that the decomposition reaction of the adsorbed organic halogen compound by the iron compound particle powder is promoted. It is considered that the amine compound adsorbs the organic halogen compound and also causes a dechlorination reaction of the organic halogen compound.

The composite catalyst for decomposing an organic halogen compound according to the present invention has an improved rate of decomposition of chlorobenzene and an improved conversion rate to carbon dioxide. The organic halogen compounds in the exhaust gas to be discharged can be efficiently reduced, and complete oxidative decomposition is promoted, so that the organic halogen compounds in fly ash can be further reduced.

[0084]

Next, examples and comparative examples of the present invention will be described.

<Iron Compound Particle Powders 1 to 7> Iron compound particle powders 1 to 7 were prepared. Table 1 shows the properties of each iron compound particle powder.

[0086]

[Table 1]

Examples 1 to 4, Comparative Example 1: The organic halogen according to the present invention in the same manner as in the embodiment of the present invention except that the type of iron compound particles and the type and amount of the transition metal element were variously changed. A composite catalyst for compound decomposition and a catalyst for comparison were obtained.

Table 2 shows various properties of the obtained composite catalyst.

Example 5: A composite catalyst in which 1.0 mol% of a cobalt compound was supported on iron compound 1 in the same manner as in the embodiment of the present invention, and heat-treated at 300 ° C. for 60 minutes.
kg and 15 g of triethanolamine (1.0 wt% with respect to the composite catalyst) were dry-mixed (1440 rpm, 5 min) at 50 ° C. with a Henschel mixer to obtain a composite catalyst supporting triethanolamine.

Table 2 shows the properties of the obtained composite catalyst.

Examples 6 to 8 and Comparative Example 2: Same as Example 5 except that the iron compound particles, the type and amount of the transition metal composite catalyst to be supported, and the type and amount of the amine compound were variously changed. Thus, a composite catalyst supported by an amine compound was obtained.

Table 2 shows the properties of the obtained composite catalyst.

In Comparative Examples 3 and 4, composite catalysts prepared using silica gel having no catalytic activity itself were used instead of the iron compound particles. Table 2 shows various characteristics of the composite catalyst.

[0094]

[Table 2]

<Decomposition Test of Organic Halogen Compounds> Use Examples 1 to 6, Comparative Use Examples 1 to 6: 50 mg of each catalyst and 5.0 × 10 ⁻⁷ mol using a pulse type catalytic reactor.
The catalyst of the composite catalyst is determined by measuring the amount of the organic halogen compound which decomposes when it is instantaneously brought into contact with various organic halogen compounds under the condition of SV = 150,000 h ^-1 at a temperature of 300 ° C. in an inert gas atmosphere. The characteristics were shown.

The decomposition rate of the organic halogen compound is a value shown by the following equation (2).

[0097]

## EQU2 ## Decomposition rate of organic halogen compound [%] = [1- (detected amount of organic halogen compound after reaction / injected amount of organic halogen compound before reaction)] × 100

Table 3 shows the results of the decomposition test of the organic halogen compound.

[0099]

[Table 3]

[0100]

The catalyst for decomposing an organic halogen compound according to the present invention has a high efficiency because a transition metal compound which promotes decomposition and, if necessary, an amine compound are supported on an iron oxide catalyst having a high activity for decomposing an organic halogen compound. Can decompose organic halogen compounds well.

[Brief description of the drawings]

FIG. 1 is a schematic view of a waste incineration facility according to the present invention.

[Explanation of symbols]

 1: Waste hopper 2: Incinerator 3: Combustion chamber 4: Burner burner port 5: Gas cooling chamber 6: Air preheater 7: Blower for supplying catalyst etc. 8: Supply tank for catalyst etc. 9: Dust collector 10: Induction blower 11 ： Chimney 12 ： Indentation blower 13 ： Flue 14-17 ： Addition supply port for composite catalyst

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C07B 35/06 B01J 23/84 311A 37/06 23/74 321A C07D 319/24 23/84 301A (72) Inventor Tomoko Okita 1-4, Meiji-Shinkai, Otake City, Hiroshima Prefecture F-term in the Otake Creation Center of Toda Kogyo Co., Ltd. BC68A BD01A BD04A BD06A CA02 CA10 CA19 DA05 EA01X EA01Y FA02 FB14 4H006 AA05 AC13 AC26 BA10 BA16 BA19 BA20 BA21 BA29 BA30 BA51 BA81 BA82

Claims (2)

[Claims] An average particle size of 0.01 to 2.0 μm, a phosphorus content of 0.02% by weight or less, and a sulfur content of 0.1 to 2.0% by weight.
One or more transition metals selected from Ni, Mn, Co, Zr, and V on the surface of each of the iron oxide-containing particles or the iron oxide particles having a sodium content of 3% by weight or less and a sodium content of 0.3% by weight or less. A composite catalyst for decomposing an organic halogen compound, wherein the compound is supported in an amount of 1 to 30 mol% based on Fe. 2. A composite catalyst for decomposing an organic halogen compound, wherein the composite catalyst for decomposing an organic halogen compound according to claim 1 carries 0.01 to 10% by weight of an amine compound.