JP3948060B2 - Halogen-containing organic compound combustion removal catalyst and combustion removal method - Google Patents

Description

【００４１】
各温度での１，２−ジクロロエタン（所謂ＥＤＣ）の浄化率および副生物である塩ビモノマー（所謂ＶＣＭ）の生成率、およびＶＣＭ以外のその他の塩素化炭化水素（所謂ＣＨＣ）の生成率を表２に示した。
【００４２】
【表２】

【００４３】
なお、ＥＤＣの浄化率および副生物であるＶＣＭ、ＣＨＣの生成率は次式から求めた値である。
【００４４】
ＥＤＣの浄化率（％）
＝（ＥＤＣin−ＥＤＣout ）／ＥＤＣin×１００
ＥＤＣin ：反応管入口ＥＤＣ濃度
ＥＤＣout ：反応管出口ＥＤＣ濃度
ＶＣＭの生成（％）
＝ＶＣＭout ／ＥＤＣin×１００
ＥＤＣin ：反応管入口ＥＤＣ濃度
ＶＣＭout ：反応管出口ＶＣＭ濃度
ＣＨＣの生成（％）
＝ＣＨＣout ／ＥＤＣin×１００
ＥＤＣin ：反応管入口ＥＤＣ濃度
ＣＨＣout ：反応管出口のＥＤＣ、ＶＣＭ以外の塩素化炭化水素濃度の
合計
【００４５】
【発明の効果】
表２の結果より、本発明の白金族元素の内少なくとも１種以上と、ＩＡ族もしくはIIＡ族元素を含有したゼオライトを触媒として用いることにより、ハロゲン含有有機化合物を含むガスからハロゲン含有有機化合物を効率よく燃焼除去できることは明らかである。従って本発明は、環境保全上極めて有意義である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a catalyst and a removal method for removing a halogen-containing organic compound from a gas containing a halogen-containing organic compound, and in particular, a catalyst for burning and removing a dilute halogen-containing organic compound contained in a gas, and combustion removal using the catalyst. It is about the method.
[0002]
[Prior art]
Halogen-containing organic compounds are produced as useful intermediate materials and products in various chemical factories, but some of them are released into the atmosphere during the production process, and are also contained in exhaust gas from waste incineration plants. Some of them are harmful to the human body, cause air pollution, and cause global warming. Some emission control technology is required, and high purification performance is required due to serious environmental problems. Yes.
[0003]
Adsorption methods, direct combustion methods, and catalytic combustion methods are known as techniques for removing halogen-containing organic compounds. The adsorption method is effective for removing a high-concentration halogen-containing organic compound, but the removal efficiency is poor when the concentration is low. Further, in the case of direct combustion, since a high temperature of 800 ° C. or higher is necessary, it is not economical and there is a concern about secondary pollution such as generation of nitrogen oxides.
[0004]
As a catalytic combustion method, for example, JP-A-3-47516 discloses a method for removing organic halides. According to this method, a metal compound and an organic halide are brought into contact with each other and decomposed to remove the organic halide, wherein the metal oxide excludes group IA and group IIA elements of the periodic table. A removal method is disclosed that is one or more selected from the group consisting of metals belonging to the third to sixth periods and a metal compound containing one or more of these metals as metal species.
[0005]
Japanese Patent Application Laid-Open No. 4-250825 discloses a method for treating a gas containing a halogen-containing organic compound, wherein the gas containing the halogen-containing organic compound is brought into contact with an acidic zeolite. According to this method, there is disclosed a method for treating a halogen-containing organic compound by contacting an acidic zeolite or an acidic zeolite carrying and / or replacing one or more metals belonging to the second to sixth periods of the periodic table. Yes.
[0006]
Japanese Patent Application Laid-Open No. 4-2884849 discloses a method for treating exhaust gas containing 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 a transition metal is supported and / or ion-exchanged on acidic zeolite or acidic zeolite.
[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 support mainly composed of zirconia. A catalyst in which at least one of these is supported and boron oxide is supported as a promoter component. The amount of the main catalyst active component supported is equivalent to 0.1 to 5% by weight in terms of metal relative to the catalyst. A catalyst having a supported amount corresponding to 2 to 5% by weight as diboron trioxide with respect to the catalyst is disclosed.
[0008]
JP-A-8-229354 discloses a method of treating an organic halogen compound with a catalyst. According to this method, the gas stream containing the organic halogen compound contains titania and tungsten oxide, the atomic ratio of Ti and W is 20 mol% or more and 95 mol% or less of Ti, W is 80 mol% or less and 5 mol% or more, and at least A method of decomposing an organic halogen compound by contacting a titania surface covered with a tungsten oxide porous layer at a temperature of 200 to 500 ° C. is disclosed.
[0009]
Japanese Patent Application Laid-Open No. 3-289773 discloses an organic chlorinated decomposition combustion treatment method. According to this method, in the method of combusting an organic chlorine compound, the organic chlorinated product is mixed with an oxygen-containing gas and a binary composite oxide composed of titanium-silicon and a ternary composite oxide composed of titanium-silicon-zirconia. There is disclosed a decomposition combustion treatment method for an organic chlorinated product, characterized in that chlorine in an organic chlorine compound is converted into HCl by contacting and burning with at least one composite oxide catalyst selected from the above.
[0010]
Japanese Examined Patent Publication No. 6-87950 discloses a method and apparatus for catalytically reacting a waste gas containing hydrocarbons, halogenated hydrocarbons and carbon monoxide. According to this method, in particular in the process of contacting waste gas containing hydrocarbons, halogenated hydrocarbons and carbon monoxide from the synthesis of vinyl chloride, the waste gas is first oxidatively decomposed at 300-800 ° C. Waste containing hydrocarbons, halogenated hydrocarbons and carbon monoxide, characterized in that it conducts to a first zone containing a catalyst and then leads to a second zone containing a catalyst for combustion after oxidation A method for catalytically reacting a gas, wherein the catalytically active material of the catalyst in the first zone optionally contains from 0.1 to 20% by weight of one or more oxide compounds of the elements Ba, Cu, Cr, Ni Catalytic reaction wherein the catalytically active material of the second zone catalyst is platinum and / or palladium or platinum and rhodium There has been disclosed.
[0011]
[Problems to be solved by the invention]
In JP-A-3-47516, JP-A-4-250825, and JP-A-4-250825, a gas containing a halogen-containing organic compound is an acidic zeolite or a metal belonging to the second to sixth periods of the periodic rate table. A method for treating a halogen-containing organic compound by contacting an acidic zeolite carrying and / or replacing at least one of the above is disclosed, but its performance is insufficient, and in the case of group IA and group IIA elements It is described as having low activity.
[0012]
Also, JP-A-3-47516, JP-A-4-250825, JP-A-4-284849, JP-A-8-38896, JP-A-8-229354, JP-A-3-289773, In addition, according to the method disclosed in Japanese Patent Publication No. 6-87950, an attempt was made to burn and remove the halogen-containing organic compound. It has been found that some compounds are by-produced.
[0013]
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 removal ability in the method for burning and removing a halogen-containing organic compound.
[0014]
[Means for Solving the Problems]
As a result of intensive studies to solve the above problems, the present inventors use zeolite having a molar ratio of SiO ₂ / Al ₂ O ₃ containing Pt group element and IA group or IIA group element of 10 or more as a catalyst. As a result, it was found that the halogen-containing organic compound can be efficiently removed from the gas containing the halogen-containing organic compound, and the present invention has been completed.
[0015]
That is, the present invention uses as a catalyst a zeolite having a molar ratio of SiO ₂ / Al ₂ O ₃ containing at least one of platinum group elements and at least one of group IA or IIA elements of 10 or more. The present invention relates to a halogen-containing organic compound combustion removal catalyst and a combustion removal method using the same.
[0016]
Hereinafter, the present invention will be described in detail.
[0017]
A 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. Chloroform, dichloromethane, trichloromethane, carbon tetrachloride , Methyl bromide, 1,2-dichloroethane, vinyl chloride monomer, monochlorobenzene, chlorofluorocarbons, 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.
[0018]
The catalyst used in the present invention is composed of a zeolite containing at least one of platinum group elements and at least one of group IA or group IIA elements.
[0019]
The composition of 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 of 0 or higher) It is a crystalline aluminosilicate having a large number of types known as natural products and synthetic products. Type of zeolite used in the present invention, in order to obtain a durable yet high _SiO 2 / _Al 2 _{O 3} molar ratio is essential and that is 10 or more. Typical examples include ferrierite, Y, mordenite, ZSM-5, ZSM-11, and beta. The halogen-containing organic compound combustion removal catalyst of the present invention is characterized by containing at least one of group IA or group IIA elements. These zeolites, also be used as natural products and synthetic products, also these _NH 4 _{Cl, NH} 4 NO _{3, (NH 4)} ion exchanged with NH ₄ form by 2 SO _4, etc., or sintering it, or Even if it is ion-exchanged into protons with a mineral acid or the like and used as the H type, there is no problem even if it finally contains at least one or more of group IA or group IIA elements.
[0020]
The halogen-containing organic compound combustion removal catalyst of the present invention is characterized by containing at least one or more of platinum group elements and at least one or more of group IA or group IIA elements.
[0021]
A platinum group element is six elements of ruthenium, osmium, rhodium, iridium, palladium, and platinum, and platinum is particularly preferable.
[0022]
The group IA or group IIA element is not particularly limited, but lithium, sodium, potassium, cesium, magnesium, calcium, strontium, and barium are preferable, and sodium is particularly preferable.
[0023]
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 support method, or the like. In the case where platinum is impregnated and supported as a platinum group element on zeolite, the zeolite may be put into a solution containing platinum ions, and then the solvent may be removed. Examples of the platinum salt used include ammine complex salts and chlorides.
[0024]
The method for adding zeolite group IA or group IIA element to the zeolite is not particularly limited, and may be performed by an ion exchange method, an impregnation support method, or the like. When sodium is ion-exchanged into zeolite, the zeolite may be charged into a solution containing sodium ions and stirred at 20 to 100 ° C. for several hours. Examples of sodium salts to be used include nitrates, acetates, oxalates and chlorides.
[0025]
The content of the platinum group element and the group IA or IIA element is not particularly limited, but in order to obtain high catalytic performance, the content of the platinum group element is expressed in weight percent, and 0.005 to 10.0 wt% Preferably, 0.01 to 5.0 wt% is more preferable. The content of the Group IA or Group IIA element is expressed in weight percent, preferably 0.01 to 20.0 wt%, and more preferably 0.1 to 10 wt%.
[0026]
The order in which the platinum group element and the group IA or IIA element are contained in the zeolite is not particularly limited, and it is sufficient that the zeolite group finally contains at least one of the platinum group elements and the group IA or IIA element.
[0027]
Zeolite containing at least one platinum group element and at least one group IA or IIA element may be used after a pretreatment such as drying or firing when used as a catalyst.
[0028]
The halogen-containing organic compound combustion removal catalyst of the present invention is molded into a predetermined shape by adding a binder such as alumina sol, silica sol, or clay, regardless of the shape or structure of the powder, pellet, honeycomb, etc. Or, it may be used after being applied to a refractory substrate such as alumina, magnesia, cordierite or the like in the shape of a honeycomb or the like by adding water to form a slurry. Further, the introduction of the metal element can be performed after molding. The space velocity, temperature, and the like when the halogen-containing organic compound is removed by combustion are not particularly limited, but are preferably a space velocity of 100 to 500,000 hr ⁻¹ and a temperature of 100 to 700 ° C.
[0029]
When the halogen-containing organic compound is removed by combustion, the gas may contain water, oxygen, hydrogen, hydrogen chloride, nitrogen oxides, sulfur oxides, hydrocarbons, fine particles, and the like.
[0030]
EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited only to these Examples.
[0031]
【Example】
Example 1 <Preparation of Catalyst 1> ₃₀ g of a mordenite-type zeolite (trade name “HSZ-620-HOA” manufactured by Tosoh Corporation) having a SiO ₂ / Al ₂ O ₃ molar ratio of 15.7 was added to a 2.26 M aqueous sodium acetate solution. The solution was put into 270 ml and stirred at 60 ° C. for 20 hours for ion exchange. After solid-liquid separation of the slurry, the zeolite cake was put into 270 ml of a 2.26 M sodium chloride aqueous solution and subjected to ion exchange operation again. After solid-liquid separation, the filtrate was washed with pure water until chloride ions were not detected, and dried at 110 ° C. for 20 hours to obtain sodium mordenite. 30 g of the sodium-type mordenite thus obtained was put into 270 ml of a 2.3 mM tetraammineplatinum monohydrate aqueous solution, dried at 80 ° C. under reduced pressure to remove the solvent, and further contain platinum at 110 ° C. It dried for a time and obtained platinum- sodium containing mordenite, and it was set as the catalyst 1. As a result of elemental analysis, platinum was 0.5 wt% in weight percent and sodium was 4.47 wt% in weight percent.
[0032]
Comparative Example 1 <Preparation of Comparative Catalyst 1>
The same procedure as in Example 1 was performed 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 4.47 wt% in weight percent.
[0033]
Comparative Example 2 <Preparation of Comparative Catalyst 2>
The same procedure as in Example 1 was conducted except that sodium was not ion-exchanged, and the obtained platinum-containing H-type mordenite was used as Comparative Catalyst 1. As a result of elemental analysis, platinum was 0.5 wt% in weight percent.
[0034]
Comparative Example 3 <Preparation of Comparative Catalyst 3> 30 g of γ-alumina (trade name “ACP-1” manufactured by Catalytic Chemical Co., Ltd.) was put into 270 ml of 2.3 mM tetraammineplatinum monohydrate aqueous solution, and the pressure was reduced at 80 ° C. By drying and removing the solvent, platinum was contained and further dried at 110 ° C. for 20 hours to obtain platinum-containing γ-alumina. As a result of elemental analysis, platinum was 0.5 wt% in weight percent.
[0035]
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 reached 7-8. The resulting precipitate was filtered and washed with pure water until there was no chloride ion. Thereafter, it was dried at 120 ° C. and fired at 650 ° C. to obtain TiO ₂ —ZrO ₂ . This TiO ₂ —ZrO ₂ was impregnated with an ammonium paratungstate aqueous solution, and 5 wt% was supported as W to obtain a comparative catalyst 4.
[0036]
Comparative Example 5 <Preparation of Comparative Catalyst 5>
To 360 ml of water heated to 70 ° C., 1.5 ml of 14 wt% ammonia water was added to adjust the pH of the solution to 9.5. Next, 180 ml of an aqueous solution containing 23.49 g of zirconium nitrate as ZrO ₂ and 191 ml of 14 wt% ammonia water were adjusted so that the pH of the reaction solution was 9.0 to 9.5, and the whole amount was obtained in 15 minutes. Were simultaneously added dropwise. After completion of the dropwise addition, the mixture was further stirred for 15 minutes to obtain a zirconia hydrate slurry having a concentration of 3.2 wt% as ZrO ₂ . The obtained slurry was filtered to obtain a zirconia hydrate cake, which was poured into 800 ml of warm water having a temperature of 50 ° C., stirred and redispersed, and then filtered. This repulp washing operation was repeated three times to obtain a zirconia hydrate cake from which ammonia content had been removed, and dried at 110 ° C. for 20 hours. 10 g of ZrO ₂ thus obtained was put into an impregnating solution containing chloroplatinic acid and boric acid, impregnated with platinum and boron, and used as 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 .
[0037]
Comparative Example 6 <Preparation of Comparative Catalyst 6>
After 30 g of titanium oxide (manufactured by Kishida Chemical) was dried at 120 ° C. for 2 hours, it was poured into 50 ml of hydrogen peroxide solution in which 24.66 g of ammonium paratungstate was dissolved, the solvent was removed, and it was dried at 110 ° C. for 20 hours. Tungsten-supported titanium oxide was obtained and used as comparative catalyst 6. The atomic ratio of Ti and W was 8: 2.
[0038]
Comparative Example 7 <Preparation of Comparative Catalyst 7>
An aqueous solution was prepared by adding 250 ml of 28 wt% ammonia water and 18 g of silica sol (Nissan Chemical “Snowtex N40”) to 400 ml of water. 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 dropped into the previous solution, and left for 15 hours after completion of the dropping. This precipitate was filtered, washed, and dried at 110 ° C. for 20 hours to obtain a titanium-silicon composite oxide.
[0039]
<Catalyst performance evaluation>
Catalyst 1 and Comparative Catalysts 1-7 were crushed after tableting and sized to 12-20 mesh, 2 ml of which was charged into an atmospheric pressure fixed bed reactor. A pretreatment was carried out at 500 ° C. for 1 hour under air flow, and then a gas having the composition shown in Table 1 was passed in 500 ml at 350 ° C. and 400 ° C., and the steady activity was measured at each temperature.
[0040]
[Table 1]

[0041]
Table 1 shows 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 rate of other chlorinated hydrocarbons other than VCM (so-called CHC) at each temperature. It was shown in 2.
[0042]
[Table 2]

[0043]
The purification rate of EDC and the production rates of VCM and CHC as by-products are values obtained from the following equations.
[0044]
EDC purification rate (%)
= (EDCin−EDCout) / EDCin × 100
EDCin: Reaction tube inlet EDC concentration EDCout: Reaction tube outlet EDC concentration VCM generation (%)
= VCMout / EDCin × 100
EDCin: Reaction tube inlet EDC concentration VCMout: Reaction tube outlet VCM concentration CHC generation (%)
= CHCout / EDCin × 100
EDCin: Reaction tube inlet EDC concentration CHCout: Total concentration of chlorinated hydrocarbons other than EDC and VCM at the reaction tube outlet
【The invention's effect】
From the results in Table 2, the halogen-containing organic compound is converted from the gas containing the halogen-containing organic compound by using at least one of the platinum group elements of the present invention and a zeolite containing a group IA or IIA element as a catalyst. It is clear that combustion can be removed efficiently. Therefore, the present invention is extremely significant for environmental conservation.

Claims (5)

Halogen-containing organic compound combustion removal catalyst comprising a zeolite having a molar ratio of SiO ₂ / Al ₂ O ₃ of 10 or more containing at least one of platinum group elements and at least one of group IA or IIA elements . The halogen-containing organic compound combustion removal catalyst according to claim 1, wherein the platinum group element is platinum. A halogen-containing organic compound combustion removal method using the halogen-containing organic compound combustion removal catalyst according to claim 1 or 2. 4. The halogen-containing organic compound combustion removal method according to claim 3, wherein the concentration of the halogen-containing organic compound is 1% or less. 5. The halogen-containing organic compound combustion removal method according to claim 3 or 4, wherein the halogen-containing organic compound is 1,2-dichloroethane.