JPH1147604A - Catalyst for combustion and removal of organic compound containing halogen, and combusting and removing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method to combust and remove halogen-contg. org. compds. by using a catalyst having a higher combusting and removing effect. SOLUTION: This catalyst for combustion and removal of halogen-contg. org. compds. comprises a zeolite catalyst containing at least one kind of platinum group element and at least one kind of IA group or IIA group element. The catalyst for combustion and removal of halogen-contg. org. compds. contains platinum as the platinum element. In the combusting and removing method of halogen-contg. org. compds., the catalyst for combustion and removal of halogen-contg. org. compds. above described is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a catalyst and a method for removing a halogen-containing organic compound from a gas containing a halogen-containing organic compound, and more particularly to a catalyst for burning and removing a dilute halogen-containing organic compound contained in a gas. And a combustion removal method using the same.

[0002]

2. Description of the Related Art Halogen-containing organic compounds are produced as useful intermediates and products in various chemical factories, but are partially released into the atmosphere during the manufacturing process and are also emitted into the exhaust gas from waste incineration plants. Some of these substances are harmful to the human body, cause air pollution, and cause global warming.Therefore, some emission control technology is required. Is needed.

[0003] As a technique for removing a halogen-containing organic compound, an adsorption method, a direct combustion method, and a catalytic combustion method are known. In the case of the adsorption method, it is effective for removing high-concentration halogen-containing organic compounds, but when the concentration is low, the removal efficiency is poor.
In the case of direct combustion, a high temperature of 800 ° C. or more is required, which is not economical, and there is a concern about secondary pollution such as generation of nitrogen oxides.

As a catalytic combustion method, for example, Japanese Patent Application Laid-Open No. 3-47
No. 516 discloses a method for removing organic halides. According to this method, there is provided a method for removing an organic halide, which comprises bringing a metal compound into contact with an organic halide to decompose the metal compound, wherein the metal oxide excludes the IA group and IIA group elements in the periodic table. A removal method is disclosed which is at least one selected from the group consisting of metals belonging to the third to sixth periods and a metal compound having at least one of these metals as a metal species.

In Japanese Patent Application Laid-Open No. 4-250825,
A method for treating a gas containing a halogen-containing organic compound, comprising contacting a gas containing a halogen-containing organic compound with an acidic zeolite is disclosed. According to this method, acidic zeolite or the second to sixth cycles of the periodicity table are used.
A method for treating a halogen-containing organic compound by contacting an acidic zeolite carrying and / or substituting one or more metals belonging to a cycle is disclosed.

JP-A-4-284849 discloses a method for treating an exhaust gas containing a 1,2-dichloroethane decomposition catalyst and 1,2-dichloroethane. According to this method, there is disclosed a 1,2-dichloroethane decomposition catalyst characterized in that an acidic zeolite or a transition metal is supported on an acidic zeolite and / or ion-exchanged.

[0007] JP-A-8-38896 discloses a catalyst for decomposing volatile organic chlorine compounds. According to this method, a catalyst capable of decomposing a volatile organic chlorine compound in the coexistence of water vapor and oxygen is selected from the group consisting of platinum, palladium, and ruthenium as a main catalytically active metal component on a carrier containing zirconia as a main component. At least one
A catalyst that carries seeds and carries boron oxide as a co-catalyst component. The amount of the main catalytic active component supported is 0.1 to 5% by weight in terms of metal relative to the catalyst. Discloses a catalyst which is equivalent to 2 to 5% by weight as boron trioxide.

In Japanese Patent Application Laid-Open No. 8-229354,
A method for treating an organic halogen compound with a catalyst is disclosed. According to this method, a gas stream containing an organic halogen compound is mixed with a mixture of titania and tungsten oxide,
A catalyst in which Ti has an atomic ratio of 20 mol% or more and 95 mol% or less, W has an atomic ratio of 80 mol% or less and 5 mol% or more, and at least the surface of titania is covered with a porous layer of tungsten oxide; A method of decomposing an organic halogen compound by contacting with an organic compound.

In Japanese Patent Application Laid-Open No. 3-2899973,
An organic chloride decomposition combustion treatment method is disclosed. According to this method, in a method of burning an organic chlorinated compound, an organic chlorinated substance is added together with an oxygen-containing gas together with titanium-
Contacting and burning with at least one complex oxide catalyst selected from a binary complex oxide made of silicon and a ternary complex oxide made of titanium-silicon-zirconia to convert chlorine in the organic chlorine compound into HCl A method for decomposing and burning organic chlorinated compounds, characterized in that they are converted into organic chlorinated compounds.

Japanese Patent Publication No. Hei 6-87950 discloses a method and an apparatus for causing a catalytic reaction of a waste gas containing a hydrocarbon, a halogenated hydrocarbon and carbon monoxide. According to this method, waste gas containing 300 hydrocarbons, halogenated hydrocarbons and carbon monoxide, especially from the synthesis of vinyl chloride, is brought into contact with the waste gas.
A hydrocarbon, a halogen, characterized in that it first conducts to a first zone containing a catalyst for oxidative decomposition and then to a second zone containing a catalyst for post-oxidation combustion at ８００800 ° C. A catalytic reaction of a waste gas containing hydrogenated hydrocarbons and carbon monoxide, wherein the catalytically active substance of the catalyst in the first zone is optionally Ba, Cu, Cr,
Ni, one or more oxidized compounds of 0.1 to 20
A catalytic process is disclosed wherein the catalytic activity of the second zone catalyst is platinum and / or palladium or platinum and rhodium.

[0011]

Problems to be Solved by the Invention
JP, JP-A-4-250825 and JP-A-4-250825
In JP-A-250825, a gas containing a halogen-containing organic compound is loaded with an acidic zeolite or one or more metals belonging to the second to sixth cycles of the periodic table.
Alternatively, a method of treating a halogen-containing organic compound by contacting it with a substituted acidic zeolite is disclosed, but its performance is insufficient, and the group IA and IIA elements have low activity. Have been.

Also, JP-A-3-47516, JP-A-4-250825, JP-A-4-284849, JP-A-8-38896, and JP-A-8-229.
According to the methods disclosed in JP-A-354-354, JP-A-3-289973, and JP-B-6-87950, combustion removal of halogen-containing organic compounds was attempted. It has been found that some of them contain by-products of halogen-containing organic compounds other than those to be removed by combustion.

An object of the present invention is to provide a method for burning and removing a halogen-containing organic compound by using a catalyst having a higher burning-removing ability.

[0014]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies in order to solve the above-mentioned problems, and as a result, using a zeolite containing a Pt group element and an IA or IIA element as a catalyst, a halogen-containing organic compound is obtained. The present inventors have found that a halogen-containing organic compound can be efficiently burned and removed from a gas containing a compound, and have completed the present invention.

That is, the present invention provides a catalyst for removing and burning a halogen-containing organic compound, which comprises using a zeolite containing at least one or more platinum group elements and at least one or more group IA or IIA element as a catalyst. And a combustion removal method using the same.

Hereinafter, the present invention will be described in detail.

The halogen-containing organic compound is an organic compound containing at least one or more of the halogen elements fluorine, chlorine, bromine, and iodine in the molecular structure, such as chloroform, dichloromethane, trichloromethane, and the like. Examples include carbon tetrachloride, methyl bromide, 1,2-dichloroethane, vinyl chloride monomer, monochlorobenzene, fluorocarbons, PCB, dioxin and the like. In the present invention, the halogen-containing organic compound is not particularly limited, but is particularly effective for 1,2-dichloroethane.

The catalyst used in the present invention comprises a zeolite containing at least one of the platinum group elements and at least one of the group IA or group IIA elements.

The zeolite is generally _{M 2 / n O · Al 2} O 3 · ySiO 2 · zH 2 O ( where, n is the valence of the cation M, y is a number of 2 or more, z
Is a number greater than or equal to 0), which is a crystalline aluminosilicate, and many types are known as natural products and synthetic products. The type of zeolite used in the present invention is not particularly limited.
It is desirable that the iO ₂ / Al ₂ O ₃ molar ratio be 10 or more. Typically, ferrierite, Y, mordenite,
ZSM-5, ZSM-11, beta and the like can be mentioned. The catalyst for removing and burning a halogen-containing organic compound according to the present invention is characterized by containing at least one or more of Group IA or Group IIA elements. These zeolites
Natural products and synthetic products can be used as they are,
The NH ₄ type ion-exchanged with H ₄ Cl, NH ₄ NO ₃ , (NH ₄ ) ₂ SO ₄ , or the like, or calcined or ion-exchanged to protons with a mineral acid or the like and used as the H-type can be used at all. Finally, it suffices to contain at least one of the group IA or group IIA elements.

The catalyst for removing and burning a halogen-containing organic compound according to the present invention is characterized by containing at least one or more of platinum group elements and at least one of IA group or IIA elements.

The platinum group elements are six elements of ruthenium, osmium, rhodium, iridium, palladium, and platinum, with platinum being preferred.

The group IA or IIA element is not particularly limited, but includes lithium, sodium, potassium, cesium,
Magnesium, calcium, strontium and barium are preferred, with sodium being preferred.

The method for incorporating the platinum group element into the zeolite is not particularly limited, and may be performed by an ion exchange method, an impregnation-supporting method, or the like. When platinum is impregnated and supported as a platinum group element on zeolite, zeolite may be charged into a solution containing platinum ions, and then the solvent may be removed. Examples of the platinum salt to be used include ammine complex salts and chlorides.

The method for incorporating a Group IA or IIA element into the zeolite is not particularly limited, and may be an ion exchange method, an impregnation-supporting method, or the like. In the case of ion exchange of sodium into zeolite, zeolite may be charged into a solution containing sodium ions and stirred at 20 to 100 ° C. for several hours. Examples of the sodium salt to be used include nitrate, acetate, oxalate, chloride and the like.

The contents of the platinum group element and the IA group or IIA element are not particularly limited. However, in order to obtain high catalytic performance, the content of the platinum group element is expressed as 0.005-10. 0 wt% is preferable, and 0.0 wt%
1-5.0 wt% is more preferable. IA or IIA
The content of group element is expressed in weight percent, 0.01
〜20.0 wt% is preferred, and 0.1-10 wt% is more preferred.

The order in which the zeolite contains the platinum group element and the IA or IIA element is not particularly limited, and it is sufficient that the zeolite finally contains at least one or more of the platinum group elements and the IA or IIA element. .

At least one of the platinum group elements and I
The zeolite containing at least one of Group A or Group IIA elements may be used after being subjected to pretreatment such as drying and calcination when used as a catalyst.

The halogen-containing organic compound combustion removal catalyst of the present invention has a predetermined shape by adding a binder such as alumina sol, silica sol, or clay, regardless of the shape and structure of the powder, pellet, and honeycomb. Or into a slurry by adding water, alumina such as honeycomb,
It may be used after being applied on a refractory substrate such as magnesia or cordierite. Further, the introduction of the metal element can be performed after the molding. Space velocity, temperature, etc. when burning and removing the halogen-containing organic compound are not particularly limited,
Space velocity 100 to 500,000 hr ^-1 , temperature 100 to 7
Preferably it is 00 ° C.

When the halogen-containing organic compound is burned off, water, oxygen, hydrogen, hydrogen chloride, nitrogen oxide,
It may contain sulfur oxides, hydrocarbons, fine particles, and the like.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

[0031]

【Example】

Example 1 <Preparation of Catalyst 1> Mordenite zeolite having a SiO ₂ / Al ₂ O ₃ molar ratio of 15.7 (trade name “HSZ-620” manufactured by Tosoh Corporation)
-HOA ”) was charged into 270 ml of a 2.26 M aqueous sodium acetate solution, and the mixture was stirred at 60 ° C for 20 hours to perform ion exchange. After solid-liquid separation of the slurry, the zeolite cake was dissolved in a 2.26 M aqueous sodium chloride solution 2
The mixture was charged into 70 ml and the ion exchange operation was performed again. After solid-liquid separation, the filtrate was washed with pure water until chloride ions were no longer detected, and dried at 110 ° C. for 20 hours to obtain sodium-type mordenite. 30 g of the sodium-type mordenite thus obtained was added to 270 ml of an aqueous 2.3 mM tetraammineplatinum monohydrate solution, and
The solvent was removed by drying under reduced pressure at 0 ° C. to contain platinum, and further dried at 110 ° C. for 20 hours.
A platinum-iron-containing mordenite was obtained and used as catalyst 1. As a result of elemental analysis, platinum was 0.5 wt% by weight and sodium was 4.47 wt% by weight.

Comparative Example 1 <Preparation of Comparative Catalyst 1> The procedure of Example 1 was repeated except that platinum was not contained, and the obtained sodium-containing mordenite was used as Comparative Catalyst 1. As a result of elemental analysis, sodium was found to be 4.47 wt% by weight.

Comparative Example 2 <Preparation of Comparative Catalyst 2> Example 1 was repeated except that sodium was not ion-exchanged.
The obtained platinum-containing H-mordenite was used as Comparative Catalyst 1. As a result of elemental analysis, platinum was 0.5% by weight in weight percent.

Comparative Example 3 <Preparation of Comparative Catalyst 3> γ-alumina (trade name “ACP-
1)) 30 g was added to 270 ml of a 2.3 mM tetraammineplatinum monohydrate aqueous solution, dried under reduced pressure at 80 ° C. and the solvent was removed to contain platinum, and further dried at 110 ° C. for 20 hours. Iron-containing γ-alumina was obtained and used as Comparative Catalyst 3. As a result of elemental analysis, platinum was 0.5% by weight in weight percent.

Comparative Example 4 <Preparation of Comparative Catalyst 4> 16 g of titanium tetrachloride and 10 g of zirconium oxychloride were dissolved in 500 ml of methanol, and an aqueous ammonia solution (28 wt%) was added to the solution until the pH became 7 to 8. The resulting precipitate was filtered and washed with pure water until chloride ions disappeared. Then dried at 120 ° C, 6
Calcination at 50 ° C. gave TiO ₂ —ZrO ₂ . This TiO
_2- ZrO ₂ was impregnated with an aqueous solution of ammonium paratungstate, and was loaded at 5 wt% as W to obtain Comparative Catalyst 4.

Comparative Example 5 <Preparation of Comparative Catalyst 5> In 360 ml of water heated to 70 ° C., 14 wt.
% Ammonia water and add p
H was set to 9.5. Then, 23.49 as ZrO ₂
g of an aqueous solution containing zirconium nitrate (180 ml) and 191 ml of 14 wt% ammonia water.
The whole amount was simultaneously dropped over 15 minutes while adjusting the pH of the reaction solution to 9.0 to 9.5. After completion of the dropwise addition, stirring was further continued for 15 minutes to obtain a zirconia hydrate slurry having a concentration of 3.2 wt% as ZrO ₂ . The resulting slurry was filtered to obtain a zirconia hydrate cake, which was poured into 800 ml of warm water at a temperature of 50 ° C., re-dispersed by stirring, and then filtered. This repulp washing operation was repeated three times to obtain a zirconia hydrate cake from which ammonia was removed, and dried at 110 ° C. for 20 hours. 10 g of the thus obtained ZrO ₂ was put into an impregnating liquid containing chloroplatinic acid and boric acid, and impregnated with platinum and boron to obtain Comparative Catalyst 5. As a result of elemental analysis, platinum was 1 wt% as Pt, and boron was ₂ wt% as B ₂ O ₃ .

Comparative Example 6 <Preparation of Comparative Catalyst 6> 30 g of titanium oxide (manufactured by Kishida Chemical) was added at 120 ° C. for 2 hours.
After drying, ammonium paratungstate 24.6
The solution was poured into 50 ml of a hydrogen peroxide solution in which 6 g was dissolved, the solvent was removed, and the resultant was dried at 110 ° C. for 20 hours to obtain a tungsten-supported titanium oxide. The atomic ratio of Ti to W was 8: 2.

COMPARATIVE EXAMPLE 7 <Preparation of Comparative Catalyst 7>
An aqueous solution was prepared by adding 0 ml and 18 g of silica sol (“Snowtex N40” manufactured by Nissan Chemical Industries, Ltd.). An aqueous solution obtained by adding 17.5 ml of 96% sulfuric acid and 153 ml of water to 28.25 g of titanyl sulfate was gradually added dropwise to the above solution, and allowed to stand for 15 hours after completion of the addition. The precipitate was filtered, washed, and dried at 110 ° C. for 20 hours to obtain a titanium-silicon composite oxide, which was used as Comparative Catalyst 7.

<Evaluation of Catalyst Performance> Catalyst 1 and Comparative Catalyst 1
To 7 were crushed after tablet molding, sized to 12 to 20 mesh, and 2 ml of the crushed powder was charged into an atmospheric pressure fixed bed reactor. After pretreatment at 500 ° C. for 1 hour under an air flow, a gas having a composition shown in Table 1 was added at 350 ° C. and 400 ° C. for 50 hours.
It was passed through 0 ml and the steady-state activity was measured at each temperature.

[0040]

[Table 1]

At each temperature, the purification rate of 1,2-dichloroethane (so-called EDC) and the production rate of by-product vinyl chloride monomer (so-called VCM), and the production of other chlorinated hydrocarbons other than VCM (so-called CHC) The rates are shown in Table 2.

[0042]

[Table 2]

The purification rate of EDC and the production rate of by-products VCM and CHC are values obtained from the following equations.

EDC purification rate (%) = (EDCin−EDCout) /
EDCin × 100 EDCin: EDC concentration at reaction tube inlet EDCout: EDC concentration at reaction tube outlet VCM generation (%) = VCMout / EDCin × 100 EDCin: EDC concentration at reaction tube inlet VCMout: VCM concentration at reaction tube outlet VCM concentration (%) = CHCout / EDCin × 100 EDCin: EDC concentration at reaction tube inlet CHCout: Total of chlorinated hydrocarbon concentrations other than EDC and VCM at reaction tube outlet

[0045]

From the results shown in Table 2, it is found that a gas containing a halogen-containing organic compound can be obtained by using a zeolite containing at least one of the platinum group elements of the present invention and a group IA or group IIA element as a catalyst. It is clear that halogen-containing organic compounds can be efficiently burned off.
Therefore, the present invention is extremely significant in environmental conservation.

Claims (5)

[Claims] 1. The method according to claim 1, wherein at least one of the platinum group elements is selected from the group consisting of
A halogen-containing organic compound combustion removal catalyst comprising a zeolite containing at least one of Group A or Group IIA elements. 2. The catalyst for removing and burning a halogen-containing organic compound according to claim 1, wherein the platinum group element is platinum. 3. A method for burning and removing a halogen-containing organic compound, comprising using the catalyst for removing and burning a halogen-containing organic compound according to claim 1 or 2. 4. The method according to claim 3, wherein the halogen-containing organic compound has a concentration of 1%.
% Or less, wherein the halogen-containing organic compound is removed by combustion. 5. The method for burning out a halogen-containing organic compound according to claim 3, wherein the halogen-containing organic compound is 1,2-dichloroethane.