KR100490835B1 - Catalyst supporting transition metal for oxidation decomposition of chloride based organic compound, method for preparing the same, and method for removing chloride based organic compound using the same - Google Patents

Abstract

The present invention relates to a catalyst for oxidative decomposition reaction which can decompose and remove chlorine-based organic compounds discharged through waste incinerator and exhaust gas of various industrial processes with high activity, a) 100 parts by weight of titanium dioxide carrier b) catalyst Iii) 0.01 to 0.1 parts by weight of cerium oxide or iron oxide; Ii) 3 to 13 parts by weight of vanadium oxide; And iii) a catalyst for oxidative decomposition reaction of a chlorine-based organic compound including a supported catalyst having 3 to 13 parts by weight of tungsten oxide, a method for preparing the same and a method for removing the chlorine-based organic compound contained in the exhaust gas using the same.

Description

Catalysts for oxidative decomposition reaction of chlorine-based organic compounds supported with transition metals and preparation methods thereof and methods for removing chlorine-based organic compounds using the same, and methods for removing chlorine-based organic compounds using the same, AND METHOD FOR PREPARING THE SAME REMOVING CHLORIDE BASED ORGANIC COMPOUND USING THE SAME}

The present invention provides a catalyst for oxidative decomposition reaction which can decompose and remove chlorine-based organic compounds discharged through waste incinerator and exhaust gas of various industrial processes with high activity, a method for preparing the same, and chlorine-based organic compounds contained in exhaust gas using the same. It relates to a removal method.

As a method of removing chlorine-based organic compounds including dioxins, secondary incineration, low frequency discharge, plasma decomposition, activated carbon or slaked adsorption, catalytic decomposition and the like are known.

The secondary incineration method removes chlorine-based organic compounds through re-incineration at a high temperature of 800 ° C. or higher, and consumes a lot of energy to maintain a high temperature and generates corrosive chlorine gas during combustion, which may damage the inner wall of the incineration chamber. There is a problem.

The low frequency discharge method is simple because the equipment is installed in an electric dust collector that processes the dust contained in the exhaust gas. However, when there are carbon compounds or aromatic compounds in the exhaust gas, there is a problem that dioxin may be generated by causing a reverse reaction inside. .

The plasma decomposition method has a high energy loss when the concentration of chlorine-based organic compounds in the exhaust gas is low, so the treated exhaust gas must be recovered as energy using facilities such as gas turbines to meet economical efficiency, and there is still a plasma technology applicable to medium and large incinerators. It is not commercialized.

In the adsorption method using activated carbon or slaked lime, when the concentration of the chlorine-based organic compound in the exhaust gas is low, the space velocity must be reduced or the facility must be made very large to show high efficiency and there is a problem that reprocessing after adsorption is required.

The catalytic decomposition method removes chlorine-based organic compounds by contacting the exhaust gas with a catalyst at a constant temperature, which is commonly applicable to the improvement of new incinerators and existing incinerators, and does not require retreatment.

In general, catalysts for decomposing chlorine-based organic compounds including dioxins have been developed from the catalyst of selective catalytic reduction for NO _x removal, and thus, catalysts supporting vanadium and / or tungsten oxide in titanium dioxide are mainly mainstream. Achieved. Recently, noble metal oxides and / or transition metal oxides such as molybdenum (Mo) and chromium (Cr) to further enhance the activity for oxidative decomposition reactions and to suppress the generation of secondary toxic substances such as carbon monoxide (CO) and chlorine gas. Is being added.

However, noble metal oxides such as platinum and palladium are known to be very susceptible to poisoning of HCl and Cl produced by decomposition reactions (Applied Catalysis B: Environmental, vol 8, pp 107-121, 1996). Therefore, in order to prevent the decrease of activity by poisoning, the crystal structure should be large and 0.3 wt% or more is reported to be appropriate when used on a carrier (Catalysis Today, vol 54, pp 107 ~, 1999). In addition, Japanese Laid-Open Patent Publication No. 7-75720 used a noble metal in an amount of 0.01 to 3% by weight, preferably 0.1 to 1% by weight. If it is lower than this range, the decomposition activity for chlorine-based organic compounds is lowered. Reported. Also in the examples of this patent 0.5% by weight of platinum or palladium oxide was used. However, the precious metal is expensive, there is a problem that the economic efficiency is lowered when used in a large amount.

US Pat. No. 5,430,230 discloses 1,2-dichlorobenzene by supporting a vanadium oxide-tungsten oxide supported titanium dioxide catalyst with noble metals such as Pt and Pd and transition metal oxides such as Cr, Mn and Cu. As a result of application to the decomposition reaction of), the catalytic activity of the noble metal oxide was improved compared to the titanium dioxide catalyst loaded with the vanadium oxide-tungsten oxide, but the catalyst having only the transition metal oxide had little effect. However, the noble metal oxide is easily poisoned by HCl or Cl ₂ produced by the decomposition reaction and is expensive, and therefore, the use of transition metal oxide is required if possible.

The present invention is to provide a catalyst for oxidative decomposition reaction of chlorine-based organic compounds having a high activity in the oxidative decomposition reaction of chlorine-based organic compounds, while carrying a small amount of the transition metal, and excellent economical efficiency and a method for preparing the same. will be.

It is still another object of the present invention to provide an economical method for removing chlorine-based organic compounds by removing oxidative decomposition reactions of chlorine-based organic compounds with high efficiency and using a low cost catalyst.

The present invention to achieve the above object,

a) to 100 parts by weight of a titanium dioxide carrier

b) as a catalyst component

   Iii) 0.01 to 0.1 parts by weight of cerium oxide or iron oxide;

   Ii) 3 to 13 parts by weight of vanadium oxide; And

   Iii) 3 to 13 parts by weight of tungsten oxide

   Supported catalyst

It provides a catalyst for the oxidative decomposition reaction of chlorine-based organic compounds comprising a.

In addition, the present invention is a method for producing a catalyst for oxidative decomposition reaction of chlorine-based organic compounds in which cerium oxide or iron oxide, vanadium oxide, and tungsten oxide are supported on a titanium dioxide carrier,

a) impregnating the titanium dioxide powder into a mixed aqueous solution of an aqueous solution of vanadium oxide precursor and an aqueous solution of tungsten oxide precursor, drying and calcining to prepare a supported catalyst carrying vanadium oxide and tungsten oxide; And

b) The supported catalyst of step a) is impregnated with an aqueous solution of cerium nitrate (Ce (NO ₃ ) ₃ .6H ₂ O) or iron nitrate (Fe (NO ₃ ) ₃ .9H ₂ O), dried and calcined. Preparing a supported catalyst on which vanadium oxide, tungsten oxide, and transition metal oxide of cerium or iron are supported;

It provides a method for producing a catalyst for oxidative decomposition reaction of chlorine-based organic compounds comprising a.

In addition, the present invention is a method for removing chlorine-based organic compounds contained in the exhaust gas to remove the exhaust gas containing the chlorine-based organic compound by oxidative decomposition at high temperature,

Exhaust gas containing chlorine-based organic compounds

Iii) 100 parts by weight of a titanium dioxide carrier

Ii) as a catalyst component

    A) 0.01 to 0.1 parts by weight of cerium oxide or iron oxide;

    B) 3 to 13 parts by weight of vanadium oxide; And

    C) 3 to 13 parts by weight of tungsten oxide

Contacting with supported catalyst

It provides a method for removing chlorine-based organic compounds contained in the exhaust gas comprising a.

Hereinafter, the present invention will be described in detail.

The present invention has confirmed that the catalyst having a small amount of a transition metal such as cerium or iron together with the vanadium and tungsten catalyst components exhibits high activity in oxidative decomposition of chlorine-based organic compounds.

To this end, the present invention provides a high activity against oxidative decomposition reaction supported by 0.01 to 0.1 parts by weight of cerium oxide or iron oxide, 3 to 13 parts by weight of vanadium oxide, and 3 to 13 parts by weight of tungsten oxide on 100 parts by weight of a titanium dioxide carrier. The present invention provides a catalyst for oxidative decomposition reaction of chlorine-based organic compounds, a method for preparing the same, and a method for removing chlorine-based organic compounds using the same, in which a low-cost transition metal is supported.

The carrier used for the catalyst for oxidative decomposition reaction of the chlorine-based organic compound of the present invention is a waste incinerator and exhaust gas of various industrial processes often contain a small amount of sulfur oxides, so the titanium dioxide resistant to poisoning of sulfur oxides as a carrier use. Particularly, titanium dioxide powder containing at least 70% by weight of anatase crystals and having a specific surface area of 50 to 150 m ² / g is preferable for the dispersion of the catalyst component and the reduction of the specific surface area. Generally, Degussa P25 with 75 wt% of anatase crystals and a surface area of 50 m ² / g is known, but recently, titanium dioxide having a surface area of 100 m ² / g or more, which is composed only of anatase, has been produced. The dispersity can be improved when the component is supported.

In the catalyst for oxidative decomposition of the chlorine-based organic compound of the present invention, a small amount of transition metal oxide of cerium oxide or iron oxide is supported on the titanium dioxide carrier as one of the catalyst components. The cerium oxide of the present invention has an oxygen storage function, and the iron oxide shows higher activity at high temperatures. Therefore, the transition metal oxide such as cerium oxide or iron oxide used in the present invention is supported on the titanium dioxide carrier together with vanadium oxide and tungsten oxide to act as a promoter, resulting in high oxidative decomposition of chlorine-based organic compounds. It will show activity.

As such, cerium oxide or iron oxide supported on the titanium dioxide carrier as a catalyst component of the catalyst for oxidative decomposition of the chlorine-based organic compound of the present invention is based on 100 parts by weight of titanium dioxide as a carrier to provide high activity to the chlorine-based organic compound. It is preferable that 0.01 to 0.1 parts by weight are supported.

Vanadium oxide supported on the titanium dioxide carrier as another catalyst component of the catalyst for oxidative decomposition of chlorine-based organic compounds of the present invention has long been recognized as a catalyst for partial oxidation reaction, but when vanadium oxide is supported on titanium dioxide, its activity is very high. It is an excellent catalyst for complete oxidation reaction. This may be due to the semiconductor properties of titanium dioxide and the correlation between electrons in d-orbital of vanadium or because of its high dispersibility when supported on titanium dioxide and the formation of crystal structures favorable for complete oxidation. Estimate. However, vanadium oxide-carrying titanium dioxide is unstable at high temperatures, and the structure of titanium dioxide is easily converted from anatase to rutile, thereby reducing the surface area. Particularly, vanadium oxide has a V ₂ O ₅ structure. When promoted.

Therefore, it is preferable to allow vanadium to exist in a + tetravalent ionic state to be supported on titanium dioxide. For example, after preparing a vanadium impregnation solution in which ammonium vanadate (NH ₄ VO ₃ ) is dissolved in an oxalic acid (C ₂ H ₂ O ₄ ) solution as a vanadium oxide precursor, the solution is impregnated with titanium dioxide to dissolve the vanadium oxide. It is to be supported on a titanium carrier. When ammonium vanadate is dissolved in an aqueous solution of oxalic acid, the initial dark yellow solution changes from green to dark blue over time, and the vanadium in the solution changes from V ⁺⁵ (VO ²⁺ ) to V ⁺⁴ (VO ^{+). 2} ) is switched to.

As such, the vanadium oxide supported on the titanium dioxide carrier as a catalyst component of the catalyst for oxidative decomposition of the chlorine-based organic compound of the present invention is 3 to 13 parts by weight based on 100 parts by weight of titanium dioxide, which is a carrier to provide high activity to the chlorine-based organic compound. It is preferable that a weight part is supported.

As another catalyst component of the catalyst for oxidative decomposition of the chlorine-based organic compound of the present invention, tungsten oxide supported on the titanium dioxide carrier suppresses surface area reduction and conversion into rutile structure that may occur in titanium dioxide at high temperature, It inhibits poisoning by sulfur oxides contained in the exhaust gas and HCl generated when decomposing the compound. It is not clearly understood whether tungsten oxide participates in the decomposition reaction, but it appears to improve the reactivity under the oxidative decomposition reaction conditions provided in the present invention.

As such, the tungsten oxide supported on the titanium dioxide carrier as the catalyst component of the catalyst for oxidative decomposition of the chlorine-based organic compound of the present invention is 3 to 13 parts by weight based on 100 parts by weight of titanium dioxide, which is a carrier to provide high activity to the chlorine-based organic compound. It is preferable that a weight part is supported.

The catalyst of the cerium oxide or iron oxide, vanadium oxide, and titanium dioxide carrier carrying tungsten oxide of the present invention may be prepared by various methods, but first, vanadium oxide and tungsten oxide are supported on the titanium dioxide carrier, followed by cerium oxide or It is preferable to support a transition metal oxide of iron oxide on a carrier.

Specifically, the titanium dioxide powder is impregnated into a mixed aqueous solution of a vanadium oxide precursor aqueous solution and a tungsten oxide precursor aqueous solution, dried, and then calcined to carry a supported catalyst in which vanadium oxide and tungsten oxide are supported on a titanium dioxide carrier (VW-based titanium dioxide catalyst). After the preparation, the prepared VW-based titanium dioxide catalyst was impregnated with cerium nitrate or iron nitrate aqueous solution, dried, and then calcined to finally convert vanadium oxide, tungsten oxide, and transition metal oxide of cerium or iron to the titanium dioxide carrier. It is to prepare a supported VW-transition metal-based supported catalyst.

More specific example

V) dissolving ammonium vanadate (NH ₄ VO ₃ ) in an aqueous solution of oxalic acid (C ₂ H ₂ O ₄ );

Ii) adding and mixing an aqueous solution of ammonium tungstate ((NH ₄ ) ₁₀ W ₁₂ O ₄₁ 5H ₂ O) to the vanadium oxalate aqueous solution;

Iii) impregnating titanium dioxide into the mixed aqueous solution to prepare a slurry;

Iii) drying the slurry at a temperature of 100 to 150 ° C., and then firing the dried product at a temperature of 450 to 550 ° C .;

Iii) impregnating the calcined product with an aqueous solution of cerium nitrate (Ce (NO ₃ ) ₃ .6H ₂ O) or iron nitrate (Fe (NO ₃ ) ₃ .9H ₂ O) to prepare a slurry; And

Iii) drying the slurry at a temperature of 100 to 150 ° C., and then firing the dried product at a temperature of 450 to 550 ° C.

It will be prepared to include.

The catalyst for oxidative decomposition reaction of the chlorine-based organic compound of the present invention prepared by such a composition and method is used to remove the chlorine-based organic compound by a conventional catalytic decomposition method. That is, by using the catalyst in the method for removing chlorine-based organic compounds of the exhaust gas comprising the step of moving the exhaust gas containing the chlorine-based organic compound to the catalyst at a high temperature, by oxidatively removing the chlorine-based organic compound contained in the exhaust gas It is. At this time, the higher the oxidative decomposition reaction temperature is advantageous, it is set to 200 to 300 ℃ for commercial use, the exhaust gas containing a chlorine-based organic compound at a space velocity of 100,000 hr ^-1 or less based on the catalyst volume of the catalyst of the present invention It is preferable to feed into the bed so that the exhaust gas and the catalyst are in contact.

The present invention will be described in more detail with reference to the following examples and comparative examples. However, an Example is for illustrating this invention and is not limited only to these.

EXAMPLE

Comparative Example 1

(Production of V-W Type Titanium Dioxide Catalyst)

11.6 g of ammonium vanadate (NH ₄ VO ₃ ) was added to 356.7 g of an aqueous solution of oxalic acid (C ₂ H ₂ O ₄ ) and stirred until it changed from an initial dark yellow color to a green color to a dark blue color.

An aqueous solution containing 5.6 g of ammonium tungstate ((NH ₄ ) ₁₀ W ₁₂ O ₄₁ .5H ₂ O) was added and mixed to the vanadium oxalate aqueous solution.

A slurry was prepared by adding 100 g of powdered titanium dioxide powder (P25 manufactured by Degussa) as a carrier to the mixed aqueous solution. The slurry was dried at a temperature of 120 ° C. and then calcined at a temperature of 520 ° C. in an air atmosphere to prepare a titanium dioxide catalyst (V-W-based titanium dioxide catalyst) carrying vanadium oxide and tungsten oxide.

Example 1

(Production of V-W-Ce Type Titanium Dioxide Catalyst)

The titanium dioxide catalyst carrying the vanadium oxide-tungsten oxide of Comparative Example 1 was impregnated in an aqueous solution containing 0.25 g of cerium nitrate (Ce (NO ₃ ) ₃ .6H ₂ O), and dried at a temperature of 120 ° C., Firing at a temperature of 520 ° C. under an air atmosphere to prepare a titanium dioxide catalyst (VW-Ce based titanium dioxide catalyst) supported with cerium oxide-vanadium oxide-tungsten oxide.

Example 2

(Production of V-W-Fe Based Titanium Dioxide Catalyst)

After impregnating the titanium dioxide catalyst carrying the vanadium oxide-tungsten oxide of Comparative Example 1 in an aqueous solution containing 0.25 g of iron nitrate (Fe (NO ₃ ) ₃ .9H ₂ O), and drying it at a temperature of 120 ℃, Firing at a temperature of 520 ° C. under an air atmosphere to prepare a titanium dioxide catalyst (VW-Fe-based titanium dioxide catalyst) supported with cerium oxide-vanadium oxide-tungsten oxide.

0.5 g of the catalysts prepared in Examples 1, 2, and Comparative Example 1 were charged to a fixed bed reactor made of pyrex having an outer diameter of 12 mm where the catalyst layer was located, and then 1,2-dichlorobenzene The removal efficiencies for (1,2-dichlorobenzen) were measured and shown in Table 1 below. The temperature during the oxidative decomposition reaction was changed from 200 to 300 ℃ and the space velocity was 25,000 hr ^-1 . At this time, in order to resemble the flue gas composition of the actual incinerator, a mixture consisting of 600 ppm 1,2-dichlorobenzne, 10 vol% oxygen and 5 vol% water was fed to the fixed bed reactor.

The small amount of cerium or iron oxide was used to increase the activity of the oxidative decomposition reaction, and the conversion was more than 90% at 250 ° C.

division Example 1 Degradation Rate of Catalyst (V-W-Ce) Example 2 Degradation Rate of Catalyst (V-W-Fe System) Comparative Example 1 Degradation Rate of Catalyst (V-W System) Reaction temperature (℃) 200 67.6 61.1 52.8 225 79.4 75.5 65.8 250 91.3 91.3 83.4 275 98.2 98.8 93.2 300 99.5 99.5 98.3

The catalyst for oxidative decomposition reaction of the chlorine-based organic compound of the present invention shows high activity in the oxidative decomposition reaction of the chlorine-based organic compound, and is an economical catalyst supporting a low-cost transition metal other than vanadium oxide and tungsten oxide on a titanium dioxide carrier.

Claims (7)

a) to 100 parts by weight of a titanium dioxide carrier b) as a catalyst component    Iii) 0.01 to 0.1 parts by weight of cerium oxide or iron oxide;    Ii) 3 to 13 parts by weight of vanadium oxide; And    Iii) 3 to 13 parts by weight of tungsten oxide    Supported catalyst Catalyst for oxidative decomposition reaction of chlorine-based organic compound comprising a. The method of claim 1, The titanium dioxide carrier of a) has a specific surface area of 50 to 150 m ² / g and a catalyst for oxidative decomposition reaction of chlorine-based organic compounds containing 70% by weight or more of anatase crystals. a) Titanium dioxide powder is impregnated into a mixed aqueous solution of a vanadium oxide precursor solution and a tungsten oxide precursor aqueous solution, dried at a temperature of 100 to 150 ° C., and calcined at a temperature of 450 to 550 ° C. to support vanadium oxide and tungsten oxide. Preparing a supported catalyst; And b) the supported catalyst of step a) is impregnated in an aqueous solution of cerium nitrate (Ce (NO ₃ ) ₃ .6H ₂ O) or iron nitrate (Fe (NO ₃ ) ₃ .9H ₂ O), and After drying at a temperature, calcining at a temperature of 450 to 550 ℃ to prepare a supported catalyst carrying vanadium oxide, tungsten oxide, and transition metal oxide of cerium or iron Method for producing a catalyst for oxidative decomposition reaction of chlorine-based organic compounds comprising a. The method of claim 3, wherein V) dissolving ammonium vanadate (NH ₄ VO ₃ ) in an aqueous solution of oxalic acid (C ₂ H ₂ O ₄ ); Ii) adding and mixing an aqueous solution of ammonium tungstate ((NH ₄ ) ₁₀ W ₁₂ O ₄₁ 5H ₂ O) to the vanadium oxalate aqueous solution; Iii) impregnating titanium dioxide into the mixed aqueous solution to prepare a slurry; Iii) drying the slurry at a temperature of 100 to 150 ° C., and then firing the dried product at a temperature of 450 to 550 ° C .; Iii) impregnating the calcined product into an aqueous solution of cerium nitrate (Ce (NO ₃ ) ₃ .6H ₂ O) or iron nitrate (Fe (NO ₃ ) ₃ .9H ₂ O) to prepare a slurry; And Iii) drying the slurry at a temperature of 100 to 150 ° C., and then firing the dried product at a temperature of 450 to 550 ° C. Method for producing a catalyst for oxidative decomposition reaction of chlorine-based organic compounds comprising a. Exhaust gas containing chlorine-based organic compounds Iii) 100 parts by weight of a titanium dioxide carrier Ii) as a catalyst component     A) 0.01 to 0.1 parts by weight of cerium oxide or iron oxide;     B) 3 to 13 parts by weight of vanadium oxide; And     C) 3 to 13 parts by weight of tungsten oxide Supported catalyst Oxidative decomposition reaction at a reaction temperature of 200 to 300 ℃ while contacting with Method for removing chlorine-based organic compounds contained in the exhaust gas comprising a. delete The method of claim 5, wherein The exhaust gas and the supported catalyst is a method for removing chlorine-based organic compounds contained in the exhaust gas in contact at a space velocity of 25,000 to 100,000 hr ^-1 based on the catalyst volume.