KR20160072283A - The Preparation of manganese oxide catalyst having a high resistance to sulfur dioxide for removal nitrogen oxide - Google Patents

Abstract

The present invention relates to a manganese-based oxide catalyst having high resistance to SO_2 for removing nitrogen oxide (NO_x), and a preparation method thereof. The manganese-based oxide catalyst has excellent activity for removing nitrogen oxide (NO_x) at low temperatures of 150 to 250°C, and has remarkable resistance to SO_2. The preparation method of the manganese-based oxide catalyst comprises the steps of: forming a gel by heating a mixture solution of manganese salt, copper salt, cobalt salt, base, and water; aging the resultant product at high temperature under high pressure; and quenching the product by injecting a large quantity of distilled water at room temperature while returning the pressure to normal atmosphere.

Description

TECHNICAL FIELD The present invention relates to a manganese-based oxide catalyst for removing nitrogen oxides (NOx) having high resistance to sulfur dioxide and a preparation method thereof,

The present invention relates to a manganese-based oxide catalyst for removing nitrogen oxides (NO _x ) having a high resistance to SO ₂ and a method for producing the same.

TECHNICAL FIELD The present invention relates to a technology for removing nitrogen oxides using a composite metal oxide catalyst, and more particularly, to a catalyst having a high resistance to SO ₂ with a low temperature catalyst based on manganese.

Global warming is a phenomenon in which global temperature rises due to the increasing concentration of carbon dioxide (CO _2), methane (CH _4), nitrous oxide (N ₂ O), hydrogen fluorocarbons (HFC), CFCs, such as a greenhouse gas (greenhouse gas) It says. The GHG reduction targets under the Kyoto Protocol are gases such as CO ₂ , CH ₄ , N ₂ O, PFC, HFC and SF _6, and the Parties that are obliged to implement the Protocol are required to take policies and measures to reduce greenhouse gases. Energy efficiency improvement, sink and reservoir protection, and renewable energy development and research. In particular, nitrous oxide (N ₂ O), when viewing the global warming (global warming potential, GWP) of CO ₂ that occurs when the combustion energy (oil, coal, etc.), fossil fuel as compared with the CO ₂ to 1, It is reported to be about 310.

NOx classifies these three nitrogen oxides in a _{NO (nitric oxide), NO 2} (nitrogen dioxide) , and N ₂ O (nitrous oxide) air quality field in the most important air pollutants. Dual NO or NO ₂ is only to cause the photochemical reaction in toxicity and atmospheric N ₂ O is non-toxic because regardless of the photochemical reaction N ₂ O is a substantial amount in the atmosphere, but although not considered to be atmospheric pollutants Recently, N ₂ O has been found to act as a greenhouse gas in the troposphere and as an ozone depleting substance in the stratosphere, it is classified as an environmental pollutant and tends to be included in nitrogen oxides. Therefore, when said nitrogen oxides NO and NO ₂ and N ₂ O stands is denoted generally NO _x.

Nitrogen oxides (NO _x ) are naturally produced by bacteria in the soil, and their concentrations are low. In most cases, more than 95% of the nitrogen oxides generated by the combustion of various combustion devices (boilers, heaters, incinerators, engines, etc.) are NO, and the nitrogen oxides generated in the combustion process are generated by thermal NO _x , prompt NO _x and fuel NO _x , and the research on each reduction is accelerating with the incidence of environmental problems. Nitrogen oxide control of these stationary pollutants can be roughly classified into pre-combustion denitration by pre-combustion, improvement of combustion method, denitration during combustion by modification of combustion apparatus, and post-combustion denitration by treatment of flue-gas.

The denitrification technique is a selective catalytic reduction (SCR) in which nitrogen oxide (NO _x ) is selectively removed in the presence of a catalyst using a reducing gas such as ammonia, carbon monoxide, hydrocarbons and hydrogen sulfide, Selective NO-catalytic reduction (SNCR), which removes ammonia or urea aqueous solution, is the most reliable method for controlling NO _x after combustion. The most reliable method is selective catalytic reduction (SCR). SCR is a reducing agent (NH ₃ series, HC series, CO) to the nitrogen oxide sikimeuroseo injection through a catalyst bed to the gas mixture was mixed with the pre-air or steam from the reactor upper operating at 250 ~ 450 ℃ in the exhaust gas (NO _x) Is decomposed into nitrogen and water. Of these, the most commonly used reducing agent is NH _3, which is most frequently used because of its high reactivity with nitrogen oxides (NO _x ). However, recently, CO is used as a reducing agent to remove nitrogen oxides (NO _x ) for automotive catalytic converters Hydrogen, such as methane, propane, and propylene, is also being studied for use as a reducing agent.

A representative NO _x removal technique using NO _x is catalyzed by SCR, and ammonia or urea is used as a reducing agent. As a result, nitrogen oxides (NO _x ) are reduced to nitrogen and water vapor. This technology is 70 ~ 90% reduction efficiency compared to other technologies, and is the highest among the denitrification technologies and is widely used as a commercial facility. The unit consists mainly of ammonia injection unit, catalytic reactor and duct for exhaust gas, and the catalytic reactor usually consists of a ceramic honeycomb type catalyst layer. The catalysts include metal oxides, zeolites, alkaline earth metals, and rare earth catalysts. TiO ₂ , WO ₃ , V ₂ O ₅ , and MoO ₃ are mainly used. However, SCR has a disadvantage that it requires a high initial investment cost and a large installation space. Most of the catalytic reaction temperature is 300 to 400 ° C, and the temperature of the exhaust gas is important because the catalyst is damaged and the efficiency is lowered. In addition, SO _x in the exhaust gas acts as a catalyst poison to shorten the lifetime of the catalyst and reacts with unreacted ammonia to form ammonium sulfate and ammonium bisulfate, as described above, and is discharged as fine particles, so that the SO _x concentration in the exhaust gas is kept low .

In order to remove nitrogen oxides (NO _x ) from flue-gases, selective catalytic reduction using ammonia as a reducing agent is mainly used in stationary sources. However, since selective catalytic reduction by ammonia requires a considerable cost for equipment, Demand for facilities is not large at present. In addition to these technologies, Techniques for decomposing and removing generated nitrogen oxides (NO _x ) using an electron beam or a low-temperature plasma for removal, and development of a technique for removing nitrogen oxides (NO _x ) released into the air using a photocatalyst are also under development.

V ₂ O ₅ / TiO ₂ is mainly used as a commercial catalyst used in SCR, and Mo, W metal oxide and the like are added in order to prevent catalytic activity and poisoning of sulfur oxide. Such a catalyst exhibits excellent denitrification characteristics, but has a problem that the optimum operating temperature is about 350 캜 at a high temperature. At this temperature, dust and many contaminants are contained in the exhaust gas, so that there is a high possibility of deactivation or poisoning of the catalyst. Further, when installed at the end of the desulfurization device and the dust removing device, additional power is required for activating the catalyst. In addition, when the SCR device is installed in the stationary source currently in operation, the lack of the installation space corresponding to the temperature range of around 350 ° C also indicates the necessity of development of the low temperature denitration catalyst.

In the conventional catalyst preparation, an aqueous solution of potassium permanganate is prepared mainly as a raw material of manganese oxide, and a carrier such as activated carbon, activated alumina, activated silica, zeolite, diatomaceous earth and general filter is impregnated into the aqueous solution to prepare a manganese oxide catalyst Application No. 10-2003-0030145, 10-2003-0037425). However, in the above-mentioned production method, the surface area of the prepared catalyst is smaller than that in the case where the carrier is not used, and the active sites are generated less per unit weight and the removal performance of nitrogen oxides (NO _x ) Not high. In addition, the production of the active groups of the catalyst is limited by the reaction conditions (oxidation after the atmospheric pressure catalyst synthesis reaction) even in the production without using the carrier.

That is, the conventional method for producing a manganese oxide catalyst has a high manufacturing cost because of the large scale and high cost of the apparatus because of the high-temperature process, and the production cost of the manganese oxide catalyst, The removal efficiency of nitrogen oxides (NO _x ) is low due to the low surface area, and there is a problem in that the facility operation cost is high due to the fuel cost for maintaining the temperature necessary for the high temperature oxidation due to the oil price era.

Along with sulfur oxides, nitrogen oxide (NO _x ), which is a representative air pollutant discharged from various combustion processes and pyrolysis processes according to industrialization, should be removed to a certain concentration or lower due to environmental risks.

As a method for removing such nitrogen oxides (NO _x ), selective catalytic reduction (SCR) is generally used, and typical catalysts used are metal oxide based catalysts (G. Ramis, J. et al. Catal., 157, 523 (1995) and G. Centi, Appli. Catal. A, 132, 179 (1995)). It has also been reported that V ₂ O ₅ / TiO ₂ catalysts (L. Pinoy, Catalyst Today, 17, 151 (1993) and G. Deo, J. Catal., 146, 334 (1994)) are particularly good. This method is a method of decomposing by reacting with a reducing agent such as ammonia at a high temperature of about 300 to 350 ° C using a catalyst of a metal oxide (NO _x ), and is relatively efficient. However, when the reaction temperature is at least 300 Deg.] C or higher.

As a method to solve these drawbacks, I. Mochida, Journal of the Chemical Society of Japan, No. 6, 885 (1991) and I. Mochida, Journal of the Japanese Chemical Society, No. 6, p.694 (1993), it is possible to decompose nitrogen oxides (NO _x ) at temperatures as low as 100 ° C. And how to do it. However, this method can lower the reaction temperature, but has a disadvantage in that the reaction efficiency is low.

And after the Korea Patent Application No. 2000-0080303 discloses dispersing a powder of V ₂ O ₅ / TiO ₂ on the molten pitch was prepared by spinning the pitch fiber containing V ₂ O ₅ / TiO ₂ is uniformly dispersed, Stabilizes, carbonizes and activates carbon nanofibers to produce an activated carbon fiber catalyst having excellent decomposition ability of nitrogen oxides (NO _x ). This method proposes a method of producing a catalyst having excellent decomposition ability of nitrogen oxides (NO _x ) compared with a method using general activated carbon or general activated carbon fiber such as I. Mochida. However, And the reduction method has a disadvantage that it is much lower in terms of conversion conversion rate.

Korean Patent Registration Nos. 10-0655133 and 10-0840721 also disclose a metal oxide catalyst for removing nitrogen oxides (NO _x ) and a manufacturing method thereof.

Although a metal oxide catalyst for removal of nitrogen oxides (NO _x ) and a method for producing the same are shown in Korean Patent Registration Nos. 10-0655133 and 10-0840721, manganese oxide catalysts are resistant to SO ₂ It has a drawback that it is not high.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the problems of the prior art, and it is an object of the present invention to provide a catalyst having a large specific surface area as compared with a conventional NO _x removal catalyst, Based catalyst having high NO _x removal efficiency with high resistance to SO ₂ .

Another object of the invention is the production of harmful nitrogen oxides (NO _x) a catalyst with an active temperature can be lowered significantly reduce operating costs as compared to a catalyst for removing a conventional nitrogen oxide (NO _x) manganese-based oxide catalyst to remove the And the like.

Still another object of the present invention is to provide a method for producing a manganese-based oxide catalyst which is simple in production process and low in production cost, thereby facilitating mass production.

The present invention also relates to a catalyst prepared by the above-described method for preparing a manganese-based oxide catalyst, which is capable of removing nitrogen oxide (NO _x ) having high resistance to SO ₂ .

SUMMARY OF THE INVENTION The present invention is directed to provide a manganese-based oxide catalyst for removing nitrogen oxides (NO _x ) having high resistance to SO ₂ and a method of manufacturing the same.

The present inventors have conducted extensive studies to produce a manganese-based oxide catalyst having a simple production process and a low production cost but high activity of removing nitrogen oxides (NO _x ). As a result, it has been found that manganese- , A cobalt salt, a base and water is heated to form a gel, aging is carried out at a high temperature and a high pressure, and after the aging process, the pressure is released to normal pressure while a large amount of distilled water at room temperature is added to quench As a result, it was found that the surface active sites and specific surface area of the prepared catalyst were increased, and the NO _x removal performance at the low temperature was remarkably improved compared to the conventional NO _x catalyst. Thus, the present invention has been accomplished. The specific surface area value of the catalyst produced in the present invention by the BET measurement method better than 200m ² / g having at least 230m ² / g value and the upper limit is the substantially eoryeowoona 1,000m ² / g or less in the range of limitation. On the other hand, in the case of the catalyst prepared from the conventional atmospheric reaction, the specific surface area by BET measurement is in the range of 130 to 180 m ² / g and the catalytic activity at low temperature is very low.

The present invention relates to a method for producing a gel, comprising the steps of: preparing a mixed solution in which a gel is formed by heating a mixture of manganese salt, copper salt, cobalt salt, base, and distilled water; aging the mixture in a state where the mixed solution, Based oxide catalyst comprising the steps of cooling distilled water while lowering the pressure of the reactor to normal pressure to cool the mixed solution in which the gel is formed, and obtaining the gel, followed by washing and calcination. The aging is carried out in a state where air is injected into the reactor and the reactor is pressurized to a pressure higher than the atmospheric pressure. More specifically, the reactor is preferably maintained at about 2 to 100 atmospheres.

The manganese-based oxide catalyst produced by the method of the present invention has a small unit particle size, a high lattice density, and a large number of protruding functional groups whose surface oxidation states are different from those of the catalytic crystal lattice synthesized at normal pressure, And the specific surface area of the catalyst is increased, so that the catalytic activity for removing nitrogen oxides (NO _x ) is remarkably improved, and at the same time, the catalyst has a high resistance to SO ₂ .

Hereinafter, the present invention will be described in more detail.

Here, unless otherwise defined in the technical terms and the scientific terms used, those having ordinary skill in the art to which the present invention belongs have the same meaning as commonly understood by those skilled in the art. Repeated descriptions of the same technical constitution and operation as those of the conventional art will be omitted.

The present invention provides a process for preparing a manganese-based oxide catalyst comprising the following preparation steps.

a) heating a mixture of manganese salt, copper salt, cobalt salt, base and distilled water to prepare a mixed solution in which a gel is formed;

b) aging the mixed liquid in which the gel is formed, into a reactor and pressurizing with air;

c) cooling the mixed solution in which the gel is formed by adding distilled water while lowering the pressure of the reactor to normal pressure after step b); And

d) washing and calcining after obtaining the gel.

The step a) is a step of preparing a mixed solution in which a gel is formed by heating a mixture of manganese salt, copper salt, cobalt salt, base and distilled water. The mixture solution in which the gel is formed is in a slurry state in which solid particles are dispersed.

The manganese chloride and cobalt salts are used such that the molar ratio of manganese / copper / cobalt is from 0.2 to 3.2. When the molar ratio of copper to the content of manganese is less than 0.2, the removal efficiency of nitrogen oxides is insufficient. When the content of copper is larger than 3.2, the catalytic activity is lowered due to the lack of manganese crystal. .

The manganese salt is a group consisting of manganese chloride (MnCl ₂ ), manganese nitrate (Mn (NO ₃ ) ₂ ), manganese sulfate (MnSO ₄ ), manganese perchlorate (Mn (ClO ₄ ) ₂ ), hydrates thereof, , And preferably includes manganese chloride or a hydrate thereof.

Wherein the copper salt is selected from the group consisting of copper chloride (CuCl ₂ ), copper nitrate (Cu (NO ₃ ) ₂ ), copper sulfate (CuSO ₄ ), copper perchlorate (Cu (ClO ₄ ) ₂ ), hydrates thereof, And preferably copper chloride or a hydrate thereof.

The cobalt salt may be selected from the group consisting of cobalt chloride (CoCl ₂ ), cobalt nitrate (Co (NO ₃ ) ₂ ), cobalt sulfate (CoSO ₄ ), hydrates thereof and mixtures thereof, Cobalt chloride or a hydrate thereof.

The concentration of the manganese chloride copper salt and the cobalt salt is preferably 0.1 to 5 mol / L, more specifically 0.2 to 3 mol / L in the mixed solution based on the sum. If the concentration is as low as less than 0.1 mol / L, gel formation may not be performed well. If the concentration is more than 5 mol / L, the particle size of the produced manganese-based oxide catalyst becomes large, An oxide having different crystallinity and different oxidation state may be formed.

The base may be sodium carbonate, sodium hydroxide or a mixture thereof. The base may be added in a range of 1 to 10 times the molar ratio of the base to the sum of the manganese salt, the copper salt and the cobalt salt in the mixed solution. When the molar ratio of the base is less than 1, there is a problem that the coked catalyst has a weak role of trapping oxygen in the air, and when the molar ratio of the base is more than 10, the oxidation reaction is slow and the catalyst performance is poor It is preferable to adjust it to the above range.

The method for preparing a manganese-based oxide catalyst according to the present invention is for producing a catalyst for simple oxidation of nitrogen oxides. In order to improve the performance of the catalyst, at least one metal selected from silver, chromium, zinc, lanthanum and neodymium Component. ≪ / RTI > In order to further include such a metal component, the mixed solution in step a) may further contain a metal additive selected from the group consisting of silver nitrate, chromium nitrate, zinc nitrate, lanthanum nitrate, neodymium nitrate, and mixtures thereof, The content is preferably in the range of 0.01 to 10% in terms of molar ratio with respect to the sum of manganese, copper and cobalt. When the content of the metal additive is less than 0.01% by mole, the effect of improving the catalytic performance is insignificant. When the content is more than 10% by mole, the active sites of the manganese-based oxide catalyst may decrease, It is because.

The heating in step a) is preferably carried out in the range of 60 to 100 ° C because if the heating temperature is lower than 60 ° C, the gel is not formed well and if the heating temperature exceeds 100 ° C, The stability of the catalyst may be lowered or the reaction rate may be excessively increased, which may make it difficult to form catalyst particles of uniform size.

In the step a), stirring may be carried out to achieve a uniform reaction. It is appropriate that the heating time of step a) is within the range of 20 minutes to 2 hours.

The preparation process according to the present invention may comprise a suitable carrier for increasing the activity of the catalyst. Examples of the carrier include alumina, silica, zirconia, titania, ceria, chromia, and mixtures thereof. A carrier containing the carrier may be prepared by adding a carrier to the mixed solution of the step a).

In the step b), the mixed solution in which the gel is formed is put into a reactor and then aged under pressure with air. The aging may be performed using a reaction device as shown in FIG. After the mixed solution having the gel formed in the reaction vessel is introduced, the reactor lid is tightened to seal the reactor and air is injected through the air inlet. It is preferable that the pressure measured by the pressure gauge is at least 2 atmospheres, more preferably at least 3 atmospheres, because the effect of pressurization may be negligible when the aging pressure is less than 2 atm. Further, although it is not necessary to limit the upper limit of the reaction pressure, if the pressure is too high, the production process may not be easy, and the specific surface area may be rather reduced. More preferably from 2 to 50 atm, and even more preferably from 3 to 10 atm. The reaction time ages the gel in the range of 1 hour to 10 hours while maintaining the above pressure. It is more preferable that the aging process is performed at a high temperature and a high pressure by maintaining the temperature of the reactor at 60 to 100 ° C. When the aging temperature is less than 60 ° C, the increase of the effect is insignificant. When the aging temperature is more than 100 ° C, the stability of the reaction system is lowered due to evaporation of water or the reaction rate is excessively increased, so that the catalytic generation of the crystalline lattice is difficult and the surface area is small.

The manganese-based oxide catalyst according to the present invention is produced by forming a relatively large number of protruding functional groups having a high crystal density and a different surface oxidation state, It is presumed that the active site is increased.

In the step c), after the step b), distilled water is added while the pressure of the reactor is lowered to atmospheric pressure to cool the mixed solution in which the gel is formed. In this manufacturing step, the reactor is depressurized and distilled water at room temperature is added thereto in an excess amount to rapidly cool the mixed solution in which the gel is formed, thereby increasing the specific surface area of the manganese-based oxide and maintaining the generated functional groups. The amount of distilled water to be added is such that the temperature of the mixed solution can be rapidly cooled from room temperature to 40 DEG C, and it is appropriate to use distilled water at a volume ratio of 5 to 10 times the volume of the mixed solution.

In the step d), the gel is filtered after the aging step, washed with distilled water, and fired to prepare a manganese-based oxide catalyst. It is preferable that the washing is carried out several times so that the content of impurities is less than 100 ppm, and the firing is carried out at a temperature range of 300 to 600 ° C. If the calcination temperature is less than 300 ° C, the oxidation of the catalyst is not completed. If the calcination temperature is more than 600 ° C, the surface area of the oxide may be undesirably low. The catalyst according to the present invention may be formed into a granular form or a pellet form before the calcination, depending on the application to be used.

The present invention provides a catalyst for removing nitrogen oxide (NO _x ) having a high resistance to SO ₂ , which comprises a manganese-based oxide catalyst produced by the above-described production method.

At this time, the manganese-based oxide catalyst can be used by mixing with a suitable binder to facilitate coating or filling. In a specific example, the binder is an inorganic material such as a silicate-based, alumina-based or ammonium zirconium carbonate-based material.

As described above, the present invention is economical because it is possible to provide a manganese-based oxide catalyst having excellent nitrogen oxide removal activity and excellent resistance to SO ₂ at a low temperature of 150 to 250 ° C.

1 is a device structure used in the catalyst synthesis method of the present invention,
2 is a photograph of a surface of a catalyst prepared in Example 1 of the present invention by SEM (scanning electron microscope)
FIG. 3 is a reaction system for measuring the nitrogen oxide (NO _x ) removal rate of the present invention, and FIG. 4 is a graph showing the relationship between the temperature at a constant space velocity (20,000 hr ^-1 ) using the catalyst prepared in Examples 1 to 4 of the present invention (NO _x ) removal efficiency while changing the nitrogen oxide (NO _x )
5 is a graph showing the removal efficiency of nitrogen oxides (NO _x ) while introducing 50 ppm of SO ₂ at a constant space velocity (15,000 hr ^-1 ) using the catalysts prepared in Examples 1 to 4 of the present invention,
6 is a graph showing the removal efficiency of nitrogen oxides (NOx) while introducing 50 ppm of SO ₂ at a constant space velocity (5,000 hr ^-1 ) using the catalyst prepared in Examples 1 to 4 of the present invention,
7 is a graph showing the removal efficiencies of nitrogen oxides (NO _x ) while changing the time while supplying 50 ppm of SO ₂ at a constant space velocity (5,000 hr ^-1 ) using the catalysts prepared in Examples 1 to 4 of the present invention Graph.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples. However, it should be understood that the present invention is not limited thereto.

After dissolving 396 g of manganese chloride hydrate (MnCl ₂₂ O) and 252 g of sodium carbonate (Na ₂ CO ₃ ) in 2 liters of distilled water, 136 g of copper chloride chloride (CuCl ₂₂ O) and 190 g of cobalt chloride hydrate (CoCl ₂ O) were dissolved in 1 liter of distilled water . The two solutions are stirred for 30 minutes while maintaining at 90 ° C. The mixture solution was poured into a stainless steel reactor as shown in FIG. 1, and air was injected thereinto to maintain the air pressure at 5 atm for aging for 4 hours. Add 10 liters of distilled water at room temperature while removing the pressure, and immediately drop the temperature. Rinse the reactant thoroughly with a large amount of distilled water until impurities such as carbon become 100 ppm or less. Molded into pellets having a diameter of 1.5 mm and then oxidized by heating at 400 DEG C for 5 hours to complete the catalyst production process. The specific surface area was measured according to the BET method and found to be 220 m 2 / g. An electron micrograph of the catalyst was shown in FIG.

FIG. 2 is a photograph of the morphology and surface morphology of the manganese-based complex oxide catalyst according to Example 1 by scanning electron microscope (SEM). The manganese-based oxides, which are spherical and irregular in shape, form many spaces and are evenly distributed. It is believed that this is due to the different conditions under which the oxides are synthesized. Even under similar basic synthesis conditions, the synthesis of manganese-based oxides under high temperature, high pressure and pressure drop conditions of this patent is different from the size and shape of the particles synthesized at atmospheric pressure It can be seen that it is different.

Referring to FIG. 2, the manganese-based oxide catalyst according to an embodiment of the present invention is formed by collecting spherical particles having a size of 5 nm or less. In an enlarged view, the particles having a length of 50 to 200 nm, It can be seen that it is grown in the longitudinal direction more than the fold, and it can be seen that a large space of 10 to 200 nm is formed between the needle bed and the spherical oxide. That is, it can be seen that the catalyst prepared according to this embodiment is a high surface area manganese-based oxide having a basic skeleton of nanoparticles of 5 nm or less.

A manganese-based oxide catalyst was prepared in the same manner as in Example 1 except that 430 g of sodium carbonate (Na ₂ CO ₃ ) was used and the aging pressure was 4 atm. BET specific surface area: 228 m ² / g.

A manganese-based oxide catalyst was prepared in the same manner as in Example 1, except that 204 g of copper chloride hydrate (CuCl ₂₂ O) was used. BET specific surface area: 237 m ² / g.

A manganese-based oxide catalyst was prepared in the same manner as in Example 1, except that 170 g of cobalt chloride hydrate (CoCl ₂₂ O) was used. BET specific surface area: 215 m ² / g.

The synthesized manganese-based oxide catalyst was constituted as shown in FIG. 3 by using a CLD-60 analyzer of Eco Physics Co. to measure the NO _x removal rate according to the temperature, the presence of water, the oxygen content, and the sulfur compound content. As shown in FIG. 3, the experimental window was composed of a gas injection part, a reactor part, and a reaction gas analysis part. The flow rate of the gas supplied to the reactor was controlled using MFC (Mass Flow Controller, SM-TEK Co.) from each cylinder of NO, N ₂ , O ₂ and NH ₃ . Further, were the supply of moisture is N ₂ is to be injected into the reactor by the water-containing through a bubbler, this time was kept constant the bubbler inner temperature to 60 ℃ using an electric furnace in the bubbler external to a constant amount of feed. The gas supply pipe is made of a stainless steel pipe as a whole, and the formation of salts such as NH ₄ NO ₃ and NH ₄ NO _{2 which} are caused by the reaction of NO and NH ₃ is prevented and the heating band is wound around the reaction gas at 180 ° C. . The reactor consisted of a stainless steel (SUS 316) reactor with an inner diameter of 20 mm and a height of 30 mm and a quartz wool to fix the catalyst layer. The temperature of the reactor was controlled by a PID temperature controller using a k-type thermocouple mounted outside the reactor. A k-type thermocouple was also installed at the top of the catalyst bed to measure the temperature of the gas inlet. All the gases were analyzed by introducing water after removing moisture from the gas using a water trap in the chiller before entering the analyzer. At this time, the temperature of the reactor was changed from 60 to 300 ° C., the concentration of NO supplied was controlled to 300 to 500 ppm, and the concentration of NH ₃ was controlled to 300 to 500 ppm. The oxygen concentration was maintained at 3 to 5% and the space velocity was made to be in the range of 10,000 to 40,000 hr ^-1 .

4 is a graph showing changes in the temperature of the catalyst prepared in Examples 1 to 4 of the present invention at 400 ppm of NO, NO / NH ₃ : 1 molar ratio, O ₂ concentration of 3% and space velocity of 20,000 hr ^-1 a graph showing the nitrogen oxide (NO _x) removal efficiency, was excellent the removal of the nitrogen oxide (NO _x) between 170 ~ 250 ℃.

Figure 5 is an embodiment 1 ~ NO, using the catalyst prepared in 4 of the present _{invention: 400ppm, NO / NH 3:} 1 molar ration, O 2 concentration: 3%, and a space velocity: the SO ₂ in 15,000hr ^-1 50ppm The NO _x removal efficiency of the catalyst is shown in FIG. 3. Even though SO ₂ is fed at 50 ppm, the manganese-based catalyst still shows resistance to SO ₂ .

FIG. 6 is a graph showing the results of measurement of NO, 400 ppm, NO / NH ₃ : 1 molar ratio, O ₂ concentration: 3% and space velocity of 5,000 hr ^-1 using the catalyst prepared in Examples 1 to 4 of the present invention, _2, while the 50ppm in a graph showing the removal efficiency of the nitrogen oxide (NO _x), the space velocity shows a slight tendency to decrease the removal capability of nitrogen oxides (NO _x), rather than when the 15,000hr ^-1.

Figure 7 is the embodiment of the invention NO 1, using the catalyst prepared in ~ 4: 400ppm, NO / NH 3: 1 molar ration, O 2 concentration: 3%, and a space velocity: the SO ₂ in 5,000hr ^-1 50ppm while a graph illustrating removal efficiency of the nitrogen oxide (NO _x) for the input time, the manganese-based oxide catalyst showed excellent resistance to SO ₂ in the time under the lasting SO ₂ present.

A manganese-based oxide catalyst was prepared in the same manner as in Example 1, except that the aging step was conducted at room temperature and atmospheric pressure for 4 hours. The specific surface area was found to be 180 m ² / g as measured by the BET method. The average particle diameter of the particles was as large as 50 nm and the shape of spherical uniformity was shown.

10: Stainless steel reaction vessel 11: Lid 12: Pressure gauge 13: Air inlet 14: Locking device 15: Viton sealing

Claims (11)

a) heating a mixture of manganese salt, copper salt, cobalt salt, base and distilled water to prepare a mixed solution in which a gel is formed;
b) adding a mixed solution having a gel formed therein to the reactor, and aging the mixture in a state of being pressurized with air;
c) cooling the mixed solution in which the gel is formed by adding distilled water while lowering the pressure of the reactor to normal pressure after step b); And
d) obtaining a gel, followed by washing and calcining.
The method according to claim 1,
Wherein the aging of step (b) is performed while maintaining the pressure of the reactor at 2 to 100 atm.
The method according to claim 1,
Wherein the manganese salt, the copper salt and the cobalt salt are used so that the manganese / copper / cobalt molar ratio is 0.2 to 3.2.
3. The method of claim 2,
Wherein the base is added in a range of 1 to 10 times the molar ratio of the base to the sum of manganese salt, copper salt and cobalt salt in the mixed solution.
The method according to claim 1,
The manganese salt is a group consisting of manganese chloride (MnCl ₂ ), manganese nitrate (Mn (NO ₃ ) ₂ ), manganese sulfate (MnSO ₄ ), manganese perchlorate (Mn (ClO ₄ ) ₂ ), hydrates thereof, Based oxide catalyst. ≪ RTI ID = 0.0 > 11. < / RTI >
The method according to claim 1,
Wherein the copper salt is selected from the group consisting of copper chloride (CuCl ₂ ), copper nitrate (Cu (NO ₃ ) ₂ ), copper sulfate (CuSO ₄ ), copper perchlorate (Cu (ClO ₄ ) ₂ ), hydrates thereof, Based oxide catalyst.
The method according to claim 1,
Wherein the cobalt salt is selected from the group consisting of cobalt chloride (CoCl ₂ ), cobalt nitrate (Co (NO ₃ ) ₂ ), cobalt sulfate (CoSO ₄ ), hydrates thereof and mixtures thereof.
The method according to claim 1,
Wherein the base is selected from sodium carbonate, sodium hydroxide or mixtures thereof.
The method according to claim 1,
The mixed solution of the step a) may include 0.01 to 10 moles of a metal additive selected from the group consisting of silver nitrate, chromium nitrate, zinc nitrate, lanthanum nitrate, neodymium nitrate, and mixtures thereof in a total amount of copper salt, manganese salt and cobalt salt % ≪ / RTI > based on the total weight of the catalyst.
The method according to claim 1,
Based oxide catalyst further comprising a carrier selected from the group consisting of alumina, silica, zirconia, titania, ceria, chromia and mixtures thereof.
A catalyst for removal of nitrogen oxides (NO _x ) having a high resistance to SO ₂ containing a manganese-based oxide catalyst having a BET surface area of 200 to 1000 m ² / g, produced by the process of any one of claims 1 to 10

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