JPH10151349A - Ammonia decomposition catalyst and method for using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the production of NOx as a by-product as well as to very efficiently decompose high concn. ammonia contained in waste gas even in a high temp. range by using an ammonia decomposition catalyst consisting of an oxide carrier and Ag. SOLUTION: One or more kinds of oxides such as titania, alumina and zeolite are used as an oxide carrier and Ag or Cu and Ag as catalytically active components are disposed preferably in the surface layer of the carrier to obtain the objective catalyst that oxides and decomposes ammonia in waste gas contg. 100-30,000ppm ammonia, an equiv. weight or more of oxygen and steam. This ammonia decomposition catalyst preferably contains Ag and Cu by 0.2-0.01 part by atom each based on 1 part of the oxide carrier. Ammonia-contg. waste gas is brought into contact with the catalyst at 200-600 deg.C, preferably 250-500 deg.C and steam is added to the waste gas by 10-60%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a novel ammonia decomposition catalyst, and more particularly, to an exhaust gas from a thermal power generation facility, a sewage treatment facility, an amine production facility, a food production facility, a human waste treatment facility in a temperature range of 200 to 600 ° C. The present invention relates to an ammonia decomposition catalyst for removing high-concentration ammonia contained therein and a method for using the same.

[0002]

2. Description of the Related Art Ammonia in exhaust gas discharged from thermal power generation facilities, sewage treatment facilities, amine production facilities, food production facilities, human waste treatment facilities, coke oven production facilities, etc. is a harmful substance or corrodes piping systems. Because the adverse effects are large,
The removal of ammonia from exhaust gas has been studied.

As a catalyst for removing ammonia in exhaust gas, Mn, Cu, Cr, Co, F is added to TiO ₂ as disclosed in, for example, JP-A-7-328440.
e, V, Ni, Mo, Zn, Rh, Ru
Harmless N ₂ by contacting ammonia at a temperature of 300-430 ° C
And H ₂ O have been proposed. 2NH ₃ + 3 / 2O ₂ → N ₂ + 3H ₂ O

On the other hand, as a system for removing ammonia in exhaust gas, for example, as disclosed in Japanese Patent Application Laid-Open No. HEI 2-125523, about 10 ppm remaining after denitrification of nitrogen oxides of gas turbine exhaust gas. It has been proposed to decompose ammonia with a catalyst in which Cu, Ag, etc. are supported on Ti. As described above, the conventionally used ammonia decomposition catalyst generates nitrogen oxides (NO, NO ₂ , N ₂ O) when oxidizing and decomposing ammonia.

2NH ₃ + 5 / 2O ₂ → 2NO + 3HO 2NH ₃ + 7 / 2O → 2NO ₂ + 3H ₂ O 2NH ₃ + 2O ₂ → N ₂ O + 3H ₂ O

[0006] Since these nitrogen oxides are air pollutants, it is strongly desired to minimize their generation.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art catalyst, and particularly to decompose highly concentrated ammonia contained in exhaust gas very efficiently in a temperature range of 200 to 600 ° C. Another object of the present invention is to provide a novel catalyst for decomposing ammonia, which has no risk of by-producing nitrogen oxides.

[0008]

Means for Solving the Problems In order to achieve the above object, the present inventors have conducted intensive studies and as a result, have found that an ammonia decomposition catalyst containing Ag is a catalyst which solves the above-mentioned problems. The invention has been completed. That is, the present invention is a catalyst for oxidatively decomposing ammonia from an exhaust gas containing 100 to 30,000 ppm of ammonia, an equivalent amount or more of oxygen and water vapor, and is characterized by containing an oxide carrier and Ag. .

Further, the present invention is a catalyst for oxidatively decomposing ammonia from an exhaust gas containing 100 to 30,000 ppm of ammonia, an equivalent amount or more of oxygen and water vapor, characterized by containing an oxide carrier and Cu and Ag. It is an ammonia decomposition catalyst. Examples of the oxide carrier include at least one selected from titania, silica, alumina, zeolite, and zirconia. The mixing ratio of the above-mentioned catalytically active component to the oxide carrier is determined by the amount of the catalytically active component Ag,
The atomic ratio of Cu is 0.2 to 0.0
Is one. Further, the shape of the catalyst may be any one of granular, honeycomb, plate, wire mesh, plate, and three-dimensional mesh.

Furthermore, the present invention relates to an ammonia treatment method for removing ammonia by oxidative decomposition with a catalyst, characterized by using any one of the above-mentioned catalysts. Further, the present invention is an ammonia treatment apparatus provided with any one of the above catalysts.

Further, the present invention is a thermal power plant equipped with the above ammonia treatment apparatus. The ammonia is efficiently removed by bringing the ammonia decomposition catalyst of the present invention into contact with the ammonia in the exhaust gas at a temperature in the range of 200 to 600 ° C. in an environmental condition in which steam and an equivalent or more of oxygen coexist, and the ammonia decomposition catalyst is subjected to heat treatment. Recovery of the catalyst activity is easily determined. The ammonia in the exhaust gas removed by the present invention may be an ammonia-containing gas contained in the exhaust gas of a thermal power generation facility, a sewage treatment facility, an amine production facility, a food production facility, a coke oven gas production facility, a human waste treatment facility, Ammonia concentration is 100 ~ 30,000pp
The range of m is preferred.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the ammonia decomposition catalyst of the present invention is a catalyst for oxidatively decomposing ammonia from an exhaust gas containing 100 to 30,000 ppm of ammonia, an equivalent or more of oxygen and water vapor. The above titania, silica, alumina, zeolite, and zirconia are used, and are preferably formed of Ag or Cu and Ag as the catalytically active components formed on the surface layer.

The preferred embodiment of the ammonia cracking catalyst according to the present invention has a specific surface area usually in the range of 10 to 500 m ² / g. There is a tendency that as the specific surface area increases, the decomposition of ammonia increases. In the ammonia decomposition catalyst of the present invention, even after removing the ammonia in the exhaust gas, the catalyst activity is easily recovered by the heat treatment, and the removal performance equivalent to the initial stage is recognized.

The ammonia decomposition catalyst of the present invention preferably contains the catalytically active components of Ag and Cu in an atomic ratio of 0.2 to 0.01 with respect to 1 part of the oxide carrier.
Then, in this range, the activity of removing the ammonia decomposition catalyst is increased. Examples of the shape of the ammonia decomposition catalyst of the present invention include a granular shape, a honeycomb shape, a plate shape, a wire mesh shape, and a three-dimensional mesh shape, and any of these can be used.
There is no particular limitation.

In the method of the present invention, the temperature at which the exhaust gas containing ammonia is brought into contact with the ammonia decomposition catalyst is as follows:
The temperature is in the temperature range of 200 to 600 ° C, preferably 250 to 500 ° C. Outside this range, the performance of removing ammonia in the exhaust gas deteriorates. In the method of the present invention, the gas space velocity at which the ammonia in the exhaust gas is brought into contact with the ammonia decomposition catalyst is in the range of 5,000 to 50,000 h ^-1 and is not particularly limited. The pressure at which the ammonia in the exhaust gas is brought into contact with the ammonia decomposition catalyst may be atmospheric pressure and is not particularly limited.

In the method of the present invention, the amount of water vapor added to the exhaust gas is preferably in the range of 10 to 60%, and outside this range, the performance of removing ammonia from the exhaust gas is reduced. The ammonia decomposition catalyst of the present invention can very easily recover its catalytic activity by heat treatment at a temperature in the range of 200 to 600 ° C. after use. The ammonia decomposition catalyst of the present invention is used for removing ammonia, and the reaction is an oxidative decomposition reaction. Thus, ammonia is converted to harmless N ₂ and H ₂ O on the ammonia decomposition catalyst in the presence of oxygen in an amount equal to or more than water vapor.

The raw materials for preparing titania, silica, alumina, zeolite and zirconia used as the oxide carrier of the ammonia decomposition catalyst of the present invention are sulfates, chlorides, nitrates, oxides, organometallic compounds and the like, and are not particularly limited. . The method of preparing the oxide carrier is not particularly limited, and may be prepared by a tableting method, a tumbling granulation method, or the like of an oxide powder obtained by a precipitation method, a hydrolysis method, a wet kneading method, or the like.

The raw materials for preparing Ag or Cu and Ag, which are the active components of the ammonia decomposition catalyst of the present invention, include, but are not particularly limited to, nitrates, sulfates, chlorides, oxides, and organometallic compounds. As means for preparing the ammonia decomposition catalyst of the present invention, Ag or C as a catalytically active component is used.
The conventional method of mixing u and Ag on the surface layer of the oxide carrier, the dipping method, the deposition method, or adding an alkali to a mixed solution of Ag or Cu and Ag of the oxide carrier component and the catalytically active component to precipitate the precipitate. There is a precipitation method for producing, and there is no particular limitation.
A specific example of the preparation of the ammonia decomposition catalyst of the present invention will be described below. That is, the powder of the oxide carrier is
It is manufactured by calcining at 500 ° C., impregnating the calcined carrier with an aqueous solution of a catalytically active component, and then drying and calcining the impregnated material.

[0019]

Embodiments of the present invention will be described below. However, the present invention is not limited to these examples. Example 1 10 g of a titania carrier powder crushed to 0.5 to 1.0 mm
Bake at 0 ° C. Silver nitrate (AgN
The O ₃ · 6H ₂ O) 3.6g were dissolved in distilled water 7 cc. Next, 10 g of a titania carrier was impregnated with the silver nitrate solution. After impregnation, it was dried at 120 ° C. for 1 hour and calcined at 500 ° C. for 2 hours to obtain a completed catalyst. This catalyst is Ti-Ag, and is Ti / Ag (atomic ratio = 1 / 0.1). This catalyst is designated as A.

Example 2 10 g of titania carrier powder crushed to 0.5 to 1.0 mm
Bake at 0 ° C. Copper nitrate (Cu
_{(NO 3) 2 · 3H 2} O) 5.1g and silver nitrate (AgNO ₃ ·
1.8 g of 6H ₂ O) was dissolved and mixed in 14 cc of distilled water. The mixed solution was impregnated into 10 g of the titania carrier in two divided portions. 1
After the second impregnation, it was dried at 120 ° C. for 1 hour and fired at 500 ° C. for 1 hour. Next, after the second impregnation, dry at 120 ° C for 1 hour, 500 ° C
For 2 hours to obtain a finished catalyst. This catalyst is Ti-Cu
-Ag, Ti / Cu (atomic ratio = 1 / 0.1), Ti /
Ag (atomic ratio = 1 / 0.05). This catalyst is designated as B.

EXAMPLE 3 10 g of a titania carrier powder crushed to 0.5 to 1.0 mm
Bake at 0 ° C. Silver nitrate (AgN
The O ₃ · 6H ₂ O) 3.6g were dissolved in distilled water 7 cc. The silver nitrate solution was impregnated with 10 g of a titania carrier. 120 after impregnation
C. for 1 hour and calcined at 500.degree. C. for 1 hour.

A chloroauric acid solution (HAuC) is used for the Ti / Ag catalyst.
impregnated with _{l 4, 50g / l) 0.2g} . After impregnation, it was dried at 120 ° C. for 1 hour and calcined at 500 ° C. for 2 hours to obtain a completed catalyst. This catalyst is Ti-Ag-Au, and Ti / Ag (atomic ratio = 1)
/0.1) and Ti / Au (atomic ratio = 1 / 0.05). This catalyst is designated as C.

Example 4 10 g of titania carrier powder crushed to 0.5 to 1.0 mm
Bake at 0 ° C. Copper nitrate (Cu
_{(NO 3) 2 · 3H 2} O) 5.1g and silver nitrate (AgNO ₃ ·
1.8 g of 6H ₂ O) was dissolved and mixed in 14 cc of distilled water. The mixed solution was impregnated into 10 g of the titania carrier in two divided portions. 1
After the second impregnation, it was dried at 120 ° C. for 1 hour and fired at 500 ° C. for 1 hour.

Next, after the second impregnation, drying was performed at 120 ° C. for 1 hour and calcination was performed at 500 ° C. for 1 hour. The Ti / Cu / Ag catalyst was impregnated with 0.2 g of a chloroauric acid solution (HAuCl ₄ , 50 g / l). After impregnation, it was dried at 120 ° C. for 1 hour and calcined at 500 ° C. for 2 hours to obtain a finished catalyst. This catalyst is Ti-Cu-Ag-Au, and has Ti / Cu (atomic ratio = 1 / 0.1), Ti / Ag (atomic ratio = 1 / 0.05), and Ti / Au (atomic ratio = 1 / 0.5). . This catalyst is designated as D.

Comparative Example 1 30 g of titania carrier powder crushed to 0.5 to 1.0 mm
Dry at 0 ° C. 10% chromium nitrate (Cr (NO ₃ )
I was immersed titania support 30g in ₃ 9H ₂ O) solution 100 g. Next, it was dried at 120 ° C. for 1 hour and fired at 600 ° C. for 2 hours. This catalyst is Cr-Ti (a known example catalyst). This catalyst is referred to as Comparative Example x.

Example 5 The catalysts A to D obtained in the above example and the catalyst X of the comparative example were used
It was installed at the center of a quartz reaction tube having a length of 19 mm and a length of 300 mm. As a simulated exhaust gas of ammonia, a gas obtained by mixing and diluting ammonia into air was introduced into the quartz reaction tube, and was brought into contact with the catalyst of the example. The change in the ammonia concentration before and after the reaction is measured by absorbing the simulated exhaust gas of ammonia into pure water to make NH ₄ ⁺ and then measuring it with an ion chromatograph to remove NH ₃ + H ₂ O → NH ₄ ⁺ + OH ^- ammonia The rate was determined. The reaction conditions are as follows.

Ammonia concentration; 3,000 ppm Water vapor concentration; 12% Residual air Reaction temperature; 300 ° C. Gas hourly space velocity; 30,000 h ^-1 (amount of gas supplied per unit time per unit catalyst volume) Amount of catalyst: 10 cc FIG. 1 shows a performance comparison between the catalysts A to D and the X catalyst of Comparative Example 1 by the method of No. 5. As is clear from FIG. 1, it was confirmed that the catalysts of Examples A to D had a higher removal rate of ammonia than the catalyst X of Comparative Example 1.

Example 6 The catalyst A of Example 1 and the catalyst B of Example 2 were the same as those of the catalyst A of Example 1 and the catalyst B of Example 1, except that a silica carrier was used instead of the titania carrier. Prepared similarly. The obtained catalyst is shown below. A1: Si-Ag A2: Si-Cu-Ag

Comparative Example 2 The same as Comparative Example 1 except that a silica carrier was used instead of the titania carrier. This catalyst is designated as X1 catalyst of Comparative Example 2. A1, A2 catalyst of Example 6 and catalyst X1 of Comparative Example 2
And the removal rate of ammonia was determined in the same manner as in Example 5. FIG. 2 shows the result. As is clear from the results shown in FIG. 2, the ammonia removal performance hardly changes even when the silica carrier is used. Further, it was confirmed that the ammonia removing performance was higher than that of the X1 catalyst of Comparative Example 2.

Example 7 The catalyst A of Example 1 and the catalyst B of Example 2 were replaced with the catalyst A of Example 1 and the catalyst B of Example 2 except that an alumina carrier was used instead of the titania carrier. Prepared. The obtained catalyst is shown below. A3: Al-Ag A4: Al-Cu-Ag

Comparative Example 3 The same as Comparative Example 1 except that an alumina carrier was used instead of the titania carrier. This catalyst is designated as X2 catalyst of Comparative Example 3. Using the A3 and A4 catalysts of Example 7 and the X2 catalyst of Comparative Example 3, the removal rate of ammonia was determined in the same manner as in Example 5. FIG. 3 shows the result. As is clear from the results of FIG. 3, even if the alumina carrier is changed, the ammonia removing performance hardly changes. Further, it was confirmed that the ammonia removing performance was higher than that of the X2 catalyst of Comparative Example 3.

Example 8 The catalyst A of Example 1 and the catalyst B of Example 2 were the same as the catalyst A of Example 1 and the catalyst B of Example 2 except that a zeolite carrier was used instead of the titania carrier. Prepared similarly. The obtained catalyst is shown below. A5: Zeolite-Ag A6: Zeolite-Cu-Ag

Comparative Example 4 The same as Comparative Example 1 except that a zeolite carrier was used instead of the titania carrier. This catalyst is referred to as a comparative X3 catalyst. Using the A5 and A6 catalysts of Example 6 and the X3 catalyst of Comparative Example 4, the removal rate of ammonia was determined in the same manner as in Example 5. FIG. 4 shows the result. As is clear from the results shown in FIG. 4, even if the zeolite carrier is changed, the ammonia removing performance hardly changes. Also,
It was confirmed that the ammonia removing performance was higher than that of the X3 catalyst 1 of Comparative Example 4.

Example 9 The catalyst A of Example 1 and the catalyst B of Example 2 were the same as those of the catalyst A of Example 1 and the catalyst B of Example 2 except that a cordierite carrier was used instead of the titania carrier. It was prepared in the same manner as described above. The obtained catalyst is shown below. A6: Cordierite-Ag A7: Cordierite-Cu-Ag

Comparative Example 4 The same as Comparative Example 1 except that a cordierite carrier was used instead of the titania carrier. This catalyst was used in Comparative Example 4 for X4
Catalyst. Using the A7 and A8 catalysts of Example 8 and the X4 catalyst of Comparative Example 4, the removal rate of ammonia was determined in the same manner as in Example 5. FIG. 5 shows the result. As is clear from the results of FIG. 5, it was confirmed that the A7 and A8 catalysts of Example 9 had higher ammonia removal performance than the comparative example catalyst.

Example 10 The following catalyst was prepared as an example catalyst. a. Ti (1) -Ag (0.005) b. Ti (1) -Ag (0.01) c. Ti (1) -Ag (0.1) e. Ti (1) -Cu (0.05) -Ag (0.05) f Ti (1) -Cu (0.1) -Ag (0.05) g. Ti (1) -Cu (0.5) -Ag (0.1) Example 5 compares the performance of the a-g catalyst with the X catalyst of Comparative Example 1. The results are shown in FIG. As is clear from FIG. 6, it was recognized that the a to g catalysts had higher ammonia removal performance than the X catalyst of Comparative Example 1.

Example 11 Using the A catalyst of Example 1 and the B catalyst of Example 2, the ammonia concentration was adjusted to 100, 1000, 500 according to the experimental method of Example 5.
The removal rate of ammonia was determined by changing to 0,10000 ppm. FIG. 7 shows the result. As is clear from the results of FIG. 7, it was confirmed that the catalyst A of Example 1 and the catalyst B of Example 2 had higher ammonia removal performance than the catalyst X of Comparative Example 1 even when the reaction temperature was changed. Was

Example 12 Using the catalyst A of Example 1 and the catalyst B of Example 2,
The atomic ratio of the active ingredient and the second active ingredient is expressed as Ti / Ag = 1 /
A mixed solution was prepared so that 0.1 and Ti / Cu / Ag = 1 / 0.1 / 0.05. Alumina honeycomb carrier (30 mm long x 30 mm wide x 200 mm long, 400 cells) in the mixed solution
Was immersed. The obtained catalyst is shown below. B1: Al-Ag B2: Al-Cu-Ag

Comparative Example 5 A 10% chromium nitrate solution was added to an alumina honeycomb carrier ((30 m long)
mx 30 mm wide x 200 mm long, 400 cells). It was dried at 120 ° C. for 1 hour and calcined at 500 ° C. for 2 hours to obtain a Y catalyst of Comparative Example 5.

Example 13 An inner diameter of a reaction tube filled with a honeycomb catalyst was 35 mm and SV
The performance test of the catalyst was performed in the same manner as in Example 5 except that was changed to 5000 h ^-1 . The performance evaluations of the B1 and B2 catalysts of Example 12 and the Y catalyst of Comparative Example 5 were examined by the above test method, and the removal rate of ammonia was determined. FIG. 8 shows the result. As is clear from the results of FIG.
It was confirmed that the B1 and B2 catalysts had higher ammonia removal performance than the catalyst Y of Comparative Example 5.

Example 14 Using the catalyst A of Example 1, a mixed solution was prepared so that the atomic ratio of Ti / Ag was 1 / 0.1. Alumina plate carrier (20mm x 35mm x 1mm thickness)
Was immersed. The obtained catalyst is shown below. B3: Al-Ti-Ag

Comparative Example 6 A 10% chromium nitrate solution was added to an alumina plate-like carrier ((length 20 mm ×
35 mm wide x 1 mm thick). It was dried at 120 ° C. for 1 hour and calcined at 500 ° C. for 2 hours to obtain a Z1 catalyst of Comparative Example 6.

Example 15 Plate-like catalysts were arranged in a stainless steel box reactor having a length of 23 mm, a width of 25 mm and a length of 40 mm at an interval of 5 sheets. It was heated from outside the stainless steel box reactor. The test method was SV 50.
A catalyst performance test was performed in the same manner as in Example 5 except that the catalyst was changed to 00h- ¹ .

The performance of the B3 catalyst of Example 14 and the Z catalyst of Comparative Example 6 were evaluated by the above-described experimental method, and the removal rate of ammonia was determined. FIG. 9 shows the result. As is clear from the results shown in FIG. 9, even if the plate-like carrier is used, it is almost the same as the granular catalyst. In addition, it was confirmed that the performance of removing ammonia was higher than that of the Z catalyst of Comparative Example 6.

Example 16 Using the catalyst A of Example 1 and the catalyst B of Example 2, the concentration of nitrogen oxide in the reaction product gas when ammonia was oxidized and decomposed was determined by the experimental method of Example 5. . The result is shown in FIG. As is clear from the results in FIG. 10, it was confirmed that the nitrogen oxide concentration was low.

Example 17 As a catalyst for an actual plant, a titania granular carrier having a particle size of 5 mm was impregnated with a silver nitrate solution so that Ti / Ag = 1 / 0.1. It was dried at 120 ° C. for 1 hour and fired at 500 ° C. for 2 hours.
The obtained catalyst is shown below. P1: Ti (1) -Ag (0.1)

Example 18 An example is shown in which the P1 catalyst of Example 17 is used by filling it in an ammonia oxidative decomposition tower of a thermal power plant wastewater treatment facility. 1000M
The wastewater of pH 1.36 containing 2 g / l of ammonia nitrogen discharged from the air heater, dust collector, condenser, etc. of the coal-fired power plant of W is continuously discharged from the storage tank at 84 t / d.
H-adjustment tank, 20% sodium hydroxide solution of 10% concentration
Ammonia was generated by addition at 0 kg / h. The waste liquid after the generation of ammonia was guided to thickener to recover sludge of heavy metals. The overflow liquid from the thickener was led to the top of an ammonia stripper of a tray type, and air was supplied from the bottom at 3500 m ³ N / h to strip ammonia. The stripped ammonia-containing gas is heated to about 350 ° C. in a heat exchanger and sent to an ammonia decomposition catalyst tower to decompose ammonia. In the thermal power plant wastewater treatment facility equipped with this series of steps, the P1 catalyst of Example 17 was used in the ammonia decomposition catalyst tower. The operating conditions are as follows.

Exhaust gas treatment amount: 3,000 m ³ / h, catalyst shape: 5 mm, catalyst filling amount: 0.3 m ³ , gas space velocity: 10,000
/ H ⁻¹ , reaction temperature: 350 ° C. As a result, the removal rate of ammonia at the outlet of the ammonia decomposition catalyst tower after 1000 hours was 99.9%, confirming that the ammonia removal performance was extremely high.

[0049]

The ammonia decomposition catalyst of the present invention has a
In the temperature range of ℃, it is possible to effectively perform the removal action under the coexistence environment of water vapor and the air above the theoretical air oxygen amount, it is possible to simplify the various equipment required for exhaust gas treatment,
In addition, additional equipment for the main equipment, such as an exhaust gas treatment device such as a sewage equipment and human waste equipment, can be easily used as an ammonia decomposition catalyst for removing ammonia.

[Brief description of the drawings]

FIG. 1 is a graph showing results of ammonia decomposition catalyst performance.

FIG. 2 is a graph showing results of ammonia decomposition catalyst performance.

FIG. 3 is a diagram showing the results of ammonia decomposition catalyst performance.

FIG. 4 is a graph showing results of ammonia decomposition catalyst performance.

FIG. 5 is a diagram showing the results of ammonia decomposition catalyst performance.

FIG. 6 is a graph showing the results of ammonia decomposition catalyst performance.

FIG. 7 is a graph showing results of ammonia decomposition catalyst performance.

FIG. 8 is a view showing the results of ammonia decomposition catalyst performance.

FIG. 9 is a view showing the results of ammonia decomposition catalyst performance.

FIG. 10 is a graph showing results of ammonia decomposition catalyst performance.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI B01J 29/072 B01D 53/36 ZABE (72) Inventor Kenji Baba 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Hitachi, Ltd. Inside Hitachi Research Laboratory (72) Inventor Yukio Murai 1-1-1 Uchikanda, Chiyoda-ku, Tokyo Inside Hitachi Plant Construction Co., Ltd. (72) Akio Tanaka 1-1-1 Uchikanda, Chiyoda-ku, Tokyo Hitachi Plant Construction Co., Ltd.

Claims (5)

[Claims] 1. A catalyst for oxidatively decomposing ammonia from an exhaust gas containing 100 to 30,000 ppm of ammonia, an equivalent or more of oxygen and water vapor, comprising an oxide carrier and Ag. 2. A catalyst for oxidatively decomposing ammonia from an exhaust gas containing 100 to 30,000 ppm of ammonia, equivalents or more of oxygen and water vapor, comprising an oxide carrier and Cu and A
An ammonia decomposition catalyst comprising g. 3. The ammonia decomposition catalyst according to claim 1, wherein the oxide carrier is at least one selected from titania, silica, alumina, zeolite, and zirconia. 4. The ammonia decomposition catalyst according to claim 1, wherein the atomic ratio of Ag and Cu of the catalytically active component is 0.2 to 0.01, respectively, relative to the oxide carrier. 5. An ammonia treatment method for removing ammonia by oxidative decomposition with a catalyst, wherein the catalyst according to any one of claims 1 to 4 is used.