KR101799030B1

KR101799030B1 - Catalyst for reducing simultaneously nitrogen monoxide and nitrous oxide from exhausted gas stream containing moisture and manufacturing method thereof

Info

Publication number: KR101799030B1
Application number: KR1020160020704A
Authority: KR
Inventors: 전상구; 유인수; 이승재; 나정걸; 문승현
Original assignee: 한국에너지기술연구원
Priority date: 2016-02-22
Filing date: 2016-02-22
Publication date: 2017-11-20
Also published as: KR20170098593A

Abstract

The present invention relates to a catalyst for simultaneous reduction of nitrogen monoxide and nitrous oxide by an ammonia reducing agent in a water-containing exhaust gas and a method of producing the same. To this end, a catalyst for simultaneous reduction of nitrogen monoxide and nitrous oxide comprises a zeolite , And the transition metal is characterized by being 0.0001 to 0.005% of the total catalyst weight.

Description

TECHNICAL FIELD The present invention relates to a catalyst for simultaneous reduction of nitrogen monoxide and nitrous oxide by an ammonia reducing agent in an exhaust gas containing water and to a method for producing the same. BACKGROUND ART [0002] The present invention relates to a catalyst for simultaneous reduction of nitrogen monoxide and nitrous oxide,

The present invention relates to a catalyst for simultaneous reduction of nitrogen monoxide and nitrous oxide by ammonia reducing agent in a water-containing exhaust gas and a method for producing the same. More particularly, the present invention relates to a catalyst for the simultaneous reduction of nitrogen monoxide and nitrous oxide in an exhaust gas containing a large amount of water such as a combustion or incineration exhaust gas. And a process for producing the catalyst by simultaneously reducing nitrogen monoxide and nitrous oxide in a single catalytic reactor under a single operating condition by using a catalyst layer composed of a single catalyst and nitrogen monoxide and nitrous oxide at a low temperature by using an ammonia reducing agent will be.

As catalysts for simultaneous reduction of nitrogen monoxide and nitrous oxide, zeolite-based catalysts in which metal ions are ion-exchanged are mainly used together with ammonia reducing agents. In Korean Patent No. 10-1091705, iron oxide-supported zeolite catalysts were used to simultaneously reduce nitrous oxide alone or nitrous oxide and nitrogen monoxide in a temperature range of 350 ° C to 400 ° C by 90% or more simultaneously.

On the other hand, a titanium oxide-based metal oxide catalyst is used for the selective reduction of nitrogen monoxide. In U.S. Patent Nos. 5,198,403 and 5,300,472, oxides in W, Si, B, Al, P, Zr, Ba, Y, La and Ce and oxides in Y, Nb, Mo, Fe, And ammonia was used as a reducing agent for selective reduction of nitrogen monoxide. More than 50% to 99% of the prepared catalysts consisted of titanium oxide. 81.1% to 94.3% of the nitrogen monoxide was reduced in the temperature range of 360 ° C to 500 ° C. U.S. Patent US 2002/0127163 A1, PCT Patent WO 02/072245 A2, and Korean Patent Laid-Open No. 10-2004-0010608 disclose the use of zeolites such as BETA, ZSM, MORD, and Y for the selective reduction of nitrogen monoxide using ammonia Fe, Cu, Co, Ce, Pt, Rh, Pd, Ir and Mg. In addition, catalysts having activity in the selective reduction of nitrous oxide among the produced catalysts were selected to selectively reduce nitrogen monoxide and nitrous oxide. The conversion rates of nitrous oxide were 80% and 99% at 450 and 500 ℃, respectively. US Pat. Nos. 6,682,710 B1, US 2004/0192538 A1 and US 7,238,641 B2 disclose a method for removing nitrous oxide and nitrogen monoxide using a catalyst obtained by ion exchanging iron ions with FER zeolite. US Pat. No. 6,872,372 B1 suggests that nitrous oxide can be selectively reduced at temperatures below 350 ° C. when palladium, rhodium, gold, or the like is added to a zeolite catalyst containing iron ions. Saturated hydrocarbons of methane or propane were used as the reducing agent. Japanese Patent No. 2006281026 discloses a method of catalytically reducing nitrogen oxides by reacting titanium oxide and at least one of titanium oxide and at least one of Cr, Mg, Fe, Co, Ni, Cu, Mo, Ru, Rh, Pd, Ag, In, Sn, W, Pt, Were mixed with one of these oxides and used as a catalyst.

These patents indicate that nitrous oxide and nitrogen monoxide can be reduced by the catalytic reduction method in the temperature range of 350 ° C to 400 ° C. However, the above-mentioned patents use a flue gas of a chemical process such as a nitric acid production process as a gas to be treated, and the moisture content in the flue gas is very small, i.e., less than 0.5%.

On the other hand, nitrogen oxide and nitrous oxide are also emitted in the exhaust gas generated when the carbon source such as coal, sewage sludge, wood, etc. is burned or incinerated, and recently it is very interested in reduction of this. Particularly, in a fluidized bed combustion furnace, the combustion temperature is relatively low as compared with other combustion furnaces, and when a fuel containing an organic substance such as sewage sludge contains a relatively large amount of nitrogen component compared to other fuels, a large amount of nitrogen monoxide As a result, about 10 to 300 ppm of nitrous oxide is emitted depending on the operating conditions. When the conventional technique is applied to such combustion or incineration flue gas, unlike the flue gas of the chemical process, the combustion and incineration flue gas contains a large amount of water, and the reduction efficiency of nitrous oxide and nitrogen monoxide is greatly deteriorated.

Therefore, in order to simultaneously reduce nitrous oxide and nitrogen monoxide in the combustion and incineration exhaust gas in a low-temperature region, a technique for producing a catalyst having resistance to moisture present in the exhaust gas is required.

Korean Patent Registration No. 10-1091705 Korean Patent Publication No. 10-2004-0010608

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is an object of the present invention to provide a flue gas which is operated under a single operation condition at a reaction temperature range of 350 to 500 ° C for a flue gas containing a large amount of moisture such as a combustion or incineration flue gas The present invention provides a catalyst for efficiently and simultaneously reducing nitrogen monoxide and nitrous oxide using ammonia as a reducing agent in a single catalytic reactor and a method for producing the same.

These and other objects and advantages of the present invention will become apparent from the following description of a preferred embodiment.

The above object is achieved by a catalyst comprising zeolite carrying iron ions and a transition metal, wherein the transition metal is supported by a simultaneous reduction catalyst of nitrogen monoxide and nitrous oxide having a weight of 0.0001 to 0.005% of the total catalyst weight.

At this time, the zeolite may include at least one of Beta (BEA), ZSM-5 (MFI), Mordenite (MOR) and Ferrierite (FER), and the transition metal may include Mn, Cu, Ni), chromium (Cr), and cobalt (Co).

The above object can also be achieved by a method for producing a zeolite comprising: a first step of supporting iron ions on a zeolite; A second step of calcining the zeolite carrying the iron ion; A third step of additionally supporting the transition metal in the zeolite carrying the sintered iron ions to 0.0001 to 0.005% of the total catalyst weight; And a fourth step of drying and calcining the zeolite to which the transition metal is additionally supported. The present invention also provides a process for producing a catalyst for simultaneous reduction of nitrogen monoxide and nitrous oxide.

In the first step, iron ions may be supported on the zeolite by ion exchange or impregnation. The zeolite may be at least one of Beta (BEA), ZSM-5 (MFI), Mordenite (MOR) and Ferrierite One can be included.

The firing in the second step may be performed in an air atmosphere at 400 to 600 ° C.

The additional supported transition metal in the third step may include at least one of manganese (Mn), copper (Cu), nickel (Ni), chromium (Cr) and cobalt (Co).

The firing in the fourth step may be performed in an air atmosphere at 400 to 600 ° C.

According to the present invention, it is possible to simultaneously reduce nitrogen monoxide and nitrous oxide present in the combustion or incineration exhaust gas containing moisture.

More specifically, reducing nitrogen monoxide and nitrous oxide in a combustion or incineration exhaust gas simultaneously by reducing the nitrogen monoxide and nitrous oxide present in water in a single catalytic reactor under a single operating condition by catalytic reduction simultaneously A separate moisture removal facility is not necessary.

However, the effects of the present invention are not limited to the above-mentioned effects, and other effects not mentioned can be clearly understood by those skilled in the art from the following description.

FIG. 1 shows conversion rates of nitrogen monoxide (a) and nitrous oxide (b) in the exhaust gas using a catalyst for simultaneous reduction of nitrogen monoxide and nitrous oxide according to an embodiment of the present invention, Graph.
2 is a graph showing conversion rates of nitrogen monoxide and nitrous oxide in the exhaust gas using the examples and comparative examples of the present invention.
FIG. 3 is a graph showing conversion rates of nitrogen monoxide and nitrous oxide in an exhaust gas having different water contents using a nitrogen monoxide and nitrous oxide simultaneous reduction catalyst according to an embodiment of the present invention.
FIG. 4 is a schematic view of a method for producing a nitrogen monoxide and nitrous oxide simultaneous reduction catalyst according to an embodiment of the present invention.

[National R & D Project Supporting the Invention]

Assignment number: 2013001690010

Department name: Ministry of Environment

Research Project: Global Top Environmental Technology Development Project

Research title: Development of high / low concentration N ₂ O reducing catalyst and integrated treatment process

Organized by: Korea Institute of Energy Research

Name of person in charge: Jeon Sanggu

Research period: 2013-11-01 ~ 2017-04-30

Hereinafter, the present invention will be described in detail with reference to embodiments and drawings of the present invention. It will be apparent to those skilled in the art that these embodiments are provided by way of illustration only for the purpose of more particularly illustrating the present invention and that the scope of the present invention is not limited by these embodiments .

Also, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains and, where contradictory, Will be given priority.

In order to clearly illustrate the claimed invention, parts not related to the description are omitted, and like reference numerals are used for like parts throughout the specification. And, when a section is referred to as "including " an element, it does not exclude other elements unless specifically stated to the contrary. In addition, "part" described in the specification means one unit or block performing a specific function.

In each step, the identification code is used for convenience of explanation, and the identification code does not describe the order of the steps, and each step may be performed differently from the stated order unless clearly specified in the context. have. That is, each of the steps may be performed in the same order as described, or may be performed substantially concurrently or in the reverse order.

The nitrogen monoxide and nitrous oxide simultaneous reduction catalyst according to an embodiment of the present invention includes iron ions and transition metal supported zeolite, and the transition metal is 0.0001 to 0.005% of the weight of the total catalyst, and ammonia is used as a reducing agent It has an effect of reducing nitrogen monoxide and nitrous oxide present in exhaust gas containing moisture in a low temperature region. In the prior art, nitrogen monoxide and nitrous oxide were not effectively reduced in the flue gas containing water. However, the present invention is characterized in that the transition metal is further supported on the zeolite carrying the iron ion, By adjusting the weight to 0.0001 to 0.005%, nitrogen monoxide and nitrous oxide can be effectively reduced even in a low temperature region. If the content of the transition metal is less than 0.0001% of the total weight of the catalyst, it is difficult to obtain the effect of the additional supported transition metal. If the content of the transition metal exceeds 0.005% And the performance of the iron ion is reduced.

Specifically, in the single catalytic reactor under a single operating condition, using the simultaneous reduction catalysts of nitrogen monoxide and nitrous oxide according to an embodiment of the present invention, Nitrogen and nitrous oxide can be simultaneously reduced. At this time, when the temperature is less than 350 ° C, the catalyst does not operate normally. When the temperature exceeds 500 ° C, the catalyst performance is deteriorated by the oxidation reaction of the ammonia reducing agent.

Further, when the water content in the flue gas exceeds 0% and is 10% or less, preferably it exceeds 0%, and when it is 5% or less, nitrogen monoxide and nitrous oxide can be effectively reduced. When the concentration of water in the flue gas exceeds 10%, the adsorption amount of nitrogen monoxide and nitrous oxide on the surface of the catalyst is greatly reduced due to moisture, and consequently, the conversion rate of nitrogen monoxide and nitrous oxide is greatly lowered.

In one embodiment, the zeolite is a carrier for supporting iron ions and a transition metal and preferably contains at least one of Beta (BEA), ZSM-5 (MFI), Mordenite (MOR) and Ferrierite (FER) Do. Further, the transition metal may be an iron oxide-impregnated zeolite which is further supported and supported on at least one of manganese (Mn), copper (Cu), nickel (Ni), chromium (Cr) and cobalt . The iron ion and the transition metal can be supported on the zeolite by ion exchange or impregnation, which will be described in detail in a method for preparing a catalyst for simultaneous reduction of nitrogen monoxide and nitrous oxide according to an embodiment of the present invention.

Meanwhile, FIG. 4 is a schematic view showing a method (S100) for producing a nitrogen monoxide and nitrous oxide simultaneous reduction catalyst according to an embodiment of the present invention. Referring to FIG. 4, a method (S100) for producing a catalyst for simultaneous reduction of nitrogen monoxide and nitrous oxide according to an embodiment of the present invention includes: a first step (S10) of supporting iron ions on a zeolite; A second step (S20) of calcining the zeolite carrying the iron ion; A third step (S30) of additionally carrying a transition metal to the zeolite carrying the sintered iron ions to 0.0001 to 0.005% of the total catalyst weight; And a fourth step (S40) of drying and firing the zeolite on which the transition metal is additionally supported. In the prior art, nitrogen monoxide and nitrous oxide were not effectively reduced in the flue gas containing water. However, in the present invention, after the iron ion is first supported on the zeolite and fired, transition from 0.0001 to 0.005% By further carrying a metal, followed by drying and firing, nitrogen monoxide and nitrous oxide can be effectively reduced even in a low temperature region. If the content of the transition metal is less than 0.0001% of the total weight of the catalyst, it is difficult to obtain the effect of the additional supported transition metal. If the content of the transition metal exceeds 0.005% And the performance of the iron ion is reduced.

Specifically, the catalyst prepared by the method (S100) for producing a catalyst for simultaneous reduction of nitrogen monoxide and nitrous oxide according to an embodiment of the present invention can be used in a single catalytic reactor under a single operation condition, The nitrogen monoxide and the nitrous oxide present in the exhaust gas containing moisture can be simultaneously reduced. At this time, when the temperature is less than 350 ° C, the catalyst does not operate normally. When the temperature exceeds 500 ° C, the catalyst performance is deteriorated by the oxidation reaction of the ammonia reducing agent.

In one embodiment, the first step (S10) is a step of supporting iron ions on the zeolite, wherein the zeolite is selected from the group consisting of Beta (BEA), ZSM-5 (MFI), Mordenite MOR) and ferrierite (FER), and the iron ion may include at least one of an iron ion precursor material such as a ferric nitrate hydrate (Fe (NO ₃ ) ₃ .9H ₂ O) Can be supported on zeolite.

As one example, a method of carrying iron ions to a zeolite through ion exchange may include: (A) pretreating the zeolite at a high temperature with water; (B) impregnating the pretreated zeolite in step (A) with a precursor solution of iron ions to form iron ions; (C) filtering and drying the zeolite particles impregnated with iron ions in step (B); And (D) repeating steps (B) and (C) to increase the iron content of the powder dried in step (C).

More specifically, it is as follows. (A) is a step of preparing a zeolite for iron ion impregnation by water treatment, wherein the zeolite used is at least one of Beta (BEA), ZSM-5 (MFI), Mordenite (MOR) and Ferrierite And one of the zeolite in which the Al ₂ O ₃ / SiO ₂ mole ratio is 5 to 100 and the cationic form in the zeolite is sodium, ammonium or hydrogen is used. It is difficult to exert the effect as a catalyst because the amount of impregnation of the iron ion is extremely low outside the range in which the mole ratio of Al ₂ O ₃ / SiO ₂ of the zeolite is out of the range. In addition, since the ionic form in the zeolite is impregnated into the zeolite by the ion exchange method, the ion exchange performance with the iron ion is lower than that of the cation form presented. The prepared zeolite is heated to 400 to 600 ° C, and 0.1 to 5 times as much moisture as the weight of the zeolite is supplied for 0.1 to 2 hours in a nitrogen atmosphere. In order to obtain the water treatment effect of the zeolite, it is preferable to carry out the water treatment in the range of the numerical limit conditions.

The step (B) is a step of preparing iron solution and impregnating zeolite with iron ion. Ferrous nitrate hydrate (Fe (NO ₃ ) ₃ .9H ₂ O) is used as a precursor material of iron ion, 1.0 molar < / RTI > This range of concentrations is intended to inhibit excess iron ion impregnation while providing the driving force that iron ions can be ion-exchanged into the zeolite. The zeolite hydrated in step (A) is added to the solution of the iron ion precursor material at a weight ratio of 0.1 to 3.0 and stirred at a temperature of 10 to 35 ° C for 5 to 30 hours. The range of these conditions is to maximize the ion exchange capacity of the iron ions to increase the amount of iron ions impregnated into the zeolite.

(C) is a step of filtering the zeolite slurry of step (B) and washing the obtained cake with 500 to 2000 ml of deionized distilled water. In this step, the iron ions in the non-ion-exchanged solution in the zeolite are removed by filtration, and the excess iron ions around the zeolite particles are removed by washing. Limiting the amount of distilled water for washing is to minimize the loss of iron ions impregnated into the zeolite while increasing the removal effect of excess iron ions. The zeolite containing iron ions obtained after washing is dried at 100-120 ° C in air for 5-24 hours. The limitation of the drying temperature and time is to remove the moisture contained in the zeolite to enhance the effect of further ion exchange and calcination in the next step.

In the step (D), the step (C) is repeated two to five times in step (B), and the number of repetitions is such that excess iron oxide is generated around zeolite particles while maximizing the amount of iron ions impregnated in the zeolite To prevent it.

In one embodiment, the second step S20 is a step of firing the iron ion-carrying zeolite to stabilize the iron ions carried in the zeolite by firing the iron ion-carrying zeolite, The influence can be minimized, and the impurities can be removed. At this time, it is preferable that the zeolite carrying the iron ion is fired in an air atmosphere of 400 to 600 ° C for 1 to 5 hours. If the temperature is lower than 400 ° C, the iron ion precursor material may not be sufficiently decomposed. If it exceeds 600 ° C, sintering of the supported iron particles may occur.

In one embodiment, the third step S30 is a step of additionally supporting the transition metal in the zeolite carrying the sintered iron ion at a ratio of 0.0001 to 0.005% of the weight of the total catalyst, wherein the transition metal is at least one selected from the group consisting of manganese (Mn) Cu), nickel (Ni), chromium (Cr), and cobalt (Co), and the nitrate precursor material is used to further carry the zeolite carrying the sintered iron ions. When the amount of the transition metal supported is less than 0.0001% of the total catalyst weight, it is difficult to obtain the effect of additionally supporting the transition metal. When the amount of the transition metal exceeds 0.005% of the total catalyst weight, The performance of the iron ion is reduced.

In one embodiment, the fourth step S40 is a step of drying and firing the zeolite on which the transition metal is additionally supported through the third step, and firing may be performed in an air atmosphere at 400 to 600 ° C. When the temperature is lower than 400 ° C., the transition metal precursor material is not sufficiently decomposed. If the temperature exceeds 600 ° C., sintering of the supported iron particles and the additional supported transition metal particles may occur.

Hereinafter, the structure and effect of the present invention will be described in more detail with reference to examples and comparative examples. However, this embodiment is intended to explain the present invention more specifically, and the scope of the present invention is not limited to these embodiments.

[Example]

The iron ion solution was prepared by dissolving 1.6 g of iron nitrate hydrate (Fe (NO ₃ ) ₃ .9H ₂ O) in 1 liter of deionized distilled water. 8 g of NH ₄ -BEA zeolite was dispersed in 1 liter of the prepared iron ion solution so that the iron ion was ion-exchanged with the zeolite. The ion exchange of iron ions was repeated three times in total. The final dried iron ion-loaded zeolite (Fe / BEA) was calcined in the air at 500 ° C for 4 hours.

Each of the nitrate precursor materials of Mn, Cu, Ni, Cr, and Co was prepared to be 0.0005% of the final catalyst weight, and impregnated with the above calcined Fe / BEA catalyst. BEA (Example 1), Cu-Fe / BEA (Example 2), and Ni-Fe / BEA (Example 1) were calcined for 4 hours at a temperature of 500 ° C. Example 3), Cr-Fe / BEA (Example 4), and Co-Fe / BEA (Example 5).

[Comparative Example]

The iron ion solution was prepared by dissolving 1.6 g of iron nitrate hydrate (Fe (NO ₃ ) ₃ .9H ₂ O) in 1 liter of deionized distilled water. 8 g of NH ₄ -BEA zeolite was dispersed in 1 liter of the prepared iron ion solution so that the iron ion was ion-exchanged with the zeolite. The ion exchange of iron ions was repeated three times in total. The final dried iron ion-loaded zeolite (Fe / BEA) was calcined in the air at 500 ° C for 4 hours. This is referred to as Comparative Example 1.

Next, the Cr nitrate precursor material (Cr (NO ₃ ) ₃ .9H ₂ O) was prepared to be 0.01% and 0.1% of the final catalyst weight, impregnated with the above calcined Fe / BEA catalyst, Comparative Example 2 (0.01%) and Comparative Example 3 (0.1%) were prepared by calcining Cr-Fe / BEA catalysts with metal added thereto at a temperature of 500 ° C for 4 hours.

[Experimental Example 1]

1.3 ml of each of the catalysts of Examples 1 to 5 was prepared and mounted in a tubular reactor. Pretreatment was carried out in an air atmosphere at 450 캜 before the reduction performance test of nitrogen monoxide and nitrous oxide.

Nitric oxide and nitrous oxide were supplied at a concentration of 300 ppm, respectively, and the concentration of ammonia reducing agent was supplied at 600 ppm. The concentrations of oxygen and water were 3% and 10%, respectively. The total flow rate of the reaction gas was fixed at 2.0 l / min using nitrogen, and the space velocity (GHSV) was maintained at 90,000 h ^-1 . After the reaction, concentrations of nitrogen monoxide and nitrous oxide were measured using an on-line gas analyzer (SIEMENS) to analyze the gas components. The reaction temperature was heated to 350 ° C and 370 ° C using an electric furnace.

1 is a graph showing conversion ratios of nitrogen monoxide (a) and nitrous oxide (b) in exhaust gas using Examples 1 to 5 and Comparative Example 1. Fig. As can be seen from FIG. 1, at the reaction temperatures of 350 ° C. and 370 ° C., the conversion of nitrogen monoxide was 89% or more for all catalysts. Therefore, the conversion of nitrogen monoxide did not decrease significantly even in the presence of 10% water. However, in the presence of 10% water, the conversion of nitrous oxide was increased at a temperature of 350 ° C compared with the case where the additional transition metal was supported on Comparative Example 1 (Fe / BEA). Particularly, in Example 4 (Cr-Fe / BEA) In the case of the present invention. In addition, the conversion of nitrous oxide was increased at a temperature of 370 ° C in the presence of 10% moisture compared to 350 ° C, and in particular, the Mn-Fe / BEA of Example 1 was significantly improved as compared with Comparative Example 1.

[Experimental Example 2]

1.3 ml of each of the catalysts of Example 4 and Comparative Examples 1 to 3 was prepared and mounted in a tubular reactor and pretreated in an air atmosphere at 450 ° C prior to the experiment for the reduction performance of nitrogen monoxide and nitrous oxide.

Nitric oxide and nitrous oxide were supplied at a concentration of 300 ppm, respectively, and the concentration of ammonia reducing agent was supplied at 600 ppm. At this time, the concentration of oxygen and water was set to 3%, and the total flow rate of the reaction gas was fixed to 2.0 l / min using nitrogen. The space velocity (GHSV) was maintained at 90,000 h ^-1 . The reaction temperature was heated to 350 ° C using an electric furnace. After the reaction, concentrations of nitrogen monoxide and nitrous oxide were measured using an on-line gas analyzer (SIEMENS) to analyze the gas components.

2 is a graph showing conversion rates of nitrogen monoxide and nitrous oxide in exhaust gas using Example 4 of the present invention and Comparative Examples 1 to 3. Fig. As can be seen from FIG. 2, the conversion rate of nitrogen monoxide was 90% or more for Example 4 and Comparative Examples 1 to 3. On the other hand, the conversion rate of nitrous oxide was the highest at 65% in Example 4 in which the loading of Cr was 0.0005%. In the case of Comparative Example 3 in which the loading of Cr was 0.10%, the conversion rate of nitrous oxide in Comparative Example 1 (Fe / BEA) in which Cr was not supported tended to be lowered to a similar degree.

[Experimental Example 3]

1.3 ml of each of the catalysts of Example 4 was prepared and mounted in a tubular reactor. Pretreatment was carried out in an air atmosphere at 450 ° C prior to the experiment for the reduction performance of nitrogen monoxide and nitrous oxide.

Nitric oxide and nitrous oxide were supplied at a concentration of 300 ppm, respectively, and the concentration of ammonia reducing agent was supplied at 600 ppm. At this time, the concentration of oxygen was set to 3%, and the total flow rate of the reaction gas was fixed to 2.0 l / min using nitrogen. The space velocity (GHSV) was maintained at 90,000 h ^-1 . The reaction temperature was heated to 350 ° C using an electric furnace. The concentration of water was adjusted to 0%, 1%, 3%, 5% and 10%. After the reaction, concentrations of nitrous oxide and nitrogen monoxide were measured using an on-line gas analyzer (SIEMENS) to analyze the gas components.

3 is a graph showing conversion rates of nitrogen monoxide and nitrous oxide in exhaust gas containing no water or containing 1%, 3%, 5% or 10% by using the catalyst of Example 4. FIG. As can be seen from FIG. 3, the conversion rate of nitrogen monoxide was 96% or more and was not significantly influenced by the change of the moisture concentration in the reaction gas. On the other hand, the conversion of nitrous oxide was highest at 1% of water concentration and lowest at 10% of water concentration. In particular, it was found that the moisture concentration did not significantly decrease in the range of the water concentration of 5% or less.

It is to be understood that the present invention is not limited to the above embodiments and various changes and modifications may be made by those skilled in the art without departing from the spirit and scope of the invention.

S100: Production method of simultaneous reduction catalyst of nitrogen monoxide and nitrous oxide
S10: First step S20: Second step
S30: Third step S40: Fourth step

Claims

An iron ion and a transition metal-supported zeolite,
The transition metal is 0.0001 to 0.005% of the total catalyst weight,
The transition metal includes at least one of manganese (Mn), copper (Cu), nickel (Ni), chromium (Cr), and cobalt (Co)
Wherein the nitrogen monoxide and the nitrous oxide in the exhaust gas having a moisture content of 10% or less are reduced.

The method according to claim 1,
Wherein the zeolite comprises at least one of Beta (BEA), ZSM-5 (MFI), Mordenite (MOR) and Ferrierite (FER).

delete

A first step of supporting iron ions on the zeolite;
A second step of calcining the zeolite carrying the iron ion;
A third step of additionally supporting the transition metal in the zeolite carrying the sintered iron ions to 0.0001 to 0.005% of the total catalyst weight; And
And a fourth step of drying and firing the zeolite on which the transition metal is additionally supported,
The transition metal in the third step,
And at least one of manganese (Mn), copper (Cu), nickel (Ni), chromium (Cr) and cobalt (Co)
Wherein the nitrogen monoxide and the nitrous oxide in the exhaust gas having a moisture content of 10% or less are reduced.

[Claim 5 is abandoned upon payment of registration fee.]

5. The method according to claim 4,
A method for producing a catalyst for simultaneous reduction of nitrogen monoxide and nitrous oxide, characterized in that iron ions are supported on a zeolite by ion exchange or impregnation.

[Claim 6 is abandoned due to the registration fee.]

5. The process according to claim 4, wherein the zeolite of the first step comprises:
Wherein the catalyst comprises at least one of Beta (BEA), ZSM-5 (MFI), Mordenite (MOR) and Ferrierite (FER).

5. The method according to claim 4, wherein in the second step,
Wherein the catalyst is carried out in an air atmosphere at 400 to 600 ° C.

delete

5. The method according to claim 4, wherein in the fourth step,
Wherein the catalyst is carried out in an air atmosphere at 400 to 600 ° C.