KR20220125364A - Nanoplatelet vanadium oxide-supported denitration catalyst and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a denitration catalyst on which nanoplatelet vanadium oxide is supported and a method for preparing the same, and more particularly, to a nanoplatelet vanadium oxide-supported catalyst prepared by applying a dispersion slurry of nanoplatelet vanadium oxide prepared by bead milling to a titania-based carrier. It relates to a titania-based denitration catalyst on which plate-shaped vanadium oxide is supported and a method for preparing the same. The denitration catalyst of the present invention includes low-temperature denitration characteristics in terms of denitration efficiency and thermal behavior.

Description

Nanoplatelet vanadium oxide-supported denitration catalyst and method for manufacturing the same

The present invention relates to a denitration catalyst supported with nanoplatelet vanadium oxide and a method for preparing the same, and more particularly, to a vanadium oxide in the form of nanoplatelets prepared by bead milling (hereinafter also referred to as 'nanoplatelet vanadium oxide'). ) to a titania-based denitration catalyst prepared by applying a dispersed slurry of a titania-based carrier to a nanoplatelet vanadium oxide-supported titania-based denitration catalyst and a method for preparing the same. The denitration catalyst of the present invention includes low-temperature denitration characteristics in terms of denitration efficiency and thermal behavior.

As energy consumption increases, the use of fossil fuels increases through thermal power plants, industrial boilers, waste incineration facilities, petrochemical plants, etc. This is becoming a problem. Nitrogen oxide (NOx), which is a representative pollutant among these combustion exhaust gases, is not only harmful to the human body but also a major cause of environmental pollution such as photochemical smog generation and acid rain.

As a prior art for the removal of such nitrogen oxides, selective catalytic reduction (SCR) is the most widely used. The selective catalytic reduction method is a denitration method in which ammonia is used as a reducing agent, mixed with NOx, and passed through a catalyst layer to remove nitrogen and water vapor in the form of nitrogen and water vapor, and a vanadium/titania catalyst is mainly used as a catalyst.

However, in the case of the vanadium/titania catalyst used in the selective catalytic reduction method, as the reaction temperature increases, ammonia is oxidized in a high-temperature region to increase the production of nitrogen oxides, and there is a problem in that the activity of the catalyst is reduced. In addition, the process at a high temperature shortens the life of the catalyst and causes corrosion of the process equipment.

In order to solve the above problems, various techniques for improving the vanadium/titanate catalyst used in the selective catalytic reduction have been developed. Among them, as techniques for improving titania carriers, for example, U.S. Patent No. 4,182,745 discloses a technique for improving the denitration efficiency by controlling the pore structure of an anatase-phase titania support in a vanadium/titania catalyst. No. 4,952,548 discloses a technique for limiting the crystal size of titania. And, US Patent No. 4,152,296 discloses a technique for improving catalyst performance by limiting the content of vanadium supported on the vanadium/titania catalyst to a specific range.

In addition, as a technique for improving the low-temperature activity of a vanadium/titania catalyst, Korean Patent Application Laid-Open No. 10-2004-0031037 specifies the contents of V ⁺⁴ and V ⁺³ and the contents of Ti ⁺³ and Ti ⁺² in the catalyst. The technology is disclosed, and Korean Patent Registration No. 10-0686381 discloses a technology of including natural manganese ore in a vanadium/titania catalyst, and Korean Patent Laid-Open No. 10-2007-0099177 discloses that vanadium is supported in titania. , discloses a technique for performing ball milling before firing after drying.

However, the above patents only disclose the physical properties of the titania carrier, specifying the content or composition of vanadium, including additional metal materials in the catalyst, or changing the catalyst manufacturing process, and the physical form of the vanadium oxide supported on the catalyst. It does not suggest at all about the technical idea that the characteristics of the catalyst, especially the denitration efficiency at low temperature, can be improved by adjusting.

An object of the present invention is to provide a denitration catalyst, particularly a denitration catalyst that can be suitably applied to a NH ₃ -SCR denitration process operated in a large combustion engine. In particular, an object of the present invention is to provide a low-temperature type denitration catalyst exhibiting high denitration efficiency in a low-temperature region by including vanadium oxide in the form of nanoplatelets.

Another object of the present invention is to provide a method for producing the low-temperature denitration catalyst.

The denitration catalyst according to the present invention is characterized in that it comprises a nanoplatelet vanadium oxide supported on a titania-based carrier.

In the denitration catalyst of the present invention, the nanoplatelet vanadium oxide may be included in an amount of 0.1 to 5.0% by weight based on the total weight of the denitration catalyst.

The vanadium oxide may be at least one selected from vanadium pentoxide (V ₂ O ₅ ), vanadium tetraoxide (V ₂ O ₄ ), and vanadium trioxide (V ₂ O ₃ ).

The nanoplatelet vanadium oxide may have a particle size of 20 to 500 nm.

The titania-based carrier is a carrier in which at least one active metal compound selected from tungsten oxide, manganese oxide, cerium oxide, molybdenum oxide and vanadium oxide is supported on a titania (TiO ₂ ) carrier including an anatase phase alone or an anatase phase can

The method for producing a denitration catalyst according to the present invention is characterized by comprising the following steps:

1) preparing an anatase-phase titania-based carrier;

2) preparing a nanoplatelet vanadium oxide;

3) supporting the nanoplatelet vanadium oxide of step 2) on the titania-based carrier of step 1);

4) sintering the result of step 3) to prepare a denitration catalyst on which nanoplatelet vanadium oxide is supported.

In the method for preparing the denitration catalyst of the present invention, step 1) may include mixing the titanium precursor compound with distilled water and then hydrolyzing, followed by solid-liquid separation, washing with water, and neutralization.

The titanium precursor compound may be at least one selected from TiOSO ₄ , TiOCl ₂ , TiCl ₄ , and TiOCH(CH ₃ ) ₂₄ .

The hydrolysis may be performed at 70-100° C. for 5 to 48 hours.

The neutralization may be performed by adjusting the pH to 7-8.

Step 1) may further include supporting at least one active metal compound selected from tungsten oxide, manganese oxide, cerium oxide, molybdenum oxide and vanadium oxide on the titania carrier obtained after the neutralization.

In the method for preparing the denitration catalyst of the present invention, step 2) for preparing the nanoplatelet vanadium oxide may be performed by mixing the additive solution with the vanadium precursor compound solution, then drying and calcining the powder obtained by bead milling. have.

The vanadium precursor compound may be at least one selected from ammonium metavanadate (NH ₄ VO ₃ ), vanadium oxytrichloride (VOCl ₃ ), and vanadium sulfate (VOSO ₄ ).

The additive may be at least one selected from polyvinyl alcohol (PVA), cellulose, ethylenediaminetetraacetic acid (EDTA), citric acid, ethylene glycol, and ammonium carbonate.

A mixing weight ratio of the vanadium precursor compound solution and the additive solution may be 1:0.1 to 1.0.

The drying may be performed at 80-100° C. for 10 to 24 hours, the calcination may be performed at 400 to 800° C. for 1 to 10 hours, and the bead milling may be performed using zirconia beads for 0.5 to 5 hours. have.

In the method for preparing a denitration catalyst of the present invention, step 3) may be performed by adding the nanoplatelet vanadium oxide slurry to the titania-based carrier slurry and impregnating it.

The impregnation treatment may be performed under conditions of 150 ~ 200mmbar, 80 ~ 100 ℃ in a rotary vacuum distiller.

In the method for producing a denitration catalyst of the present invention, the calcination in step 4) may be performed at 400 to 600° C. for 1 to 10 hours.

The denitration catalyst for NH ₃ -SCR (Selective Catalytic Reduction) according to the present invention exhibits high denitrification efficiency at low temperature range of 200 to 300°C, so that NH ₃ -SCR denitration process operated in large combustion engines such as conventional thermal power plants and industrial boilers It has the advantage of lowering the temperature range required in

In addition, according to the method for producing a denitration catalyst according to the present invention, it is possible to prepare a denitration catalyst exhibiting a denitration effect in various temperature ranges by controlling the content of the nanoplatelet vanadium oxide.

1 is a process for manufacturing a vanadium oxide in the form of nanoplatelets according to an embodiment of the present invention (Step 1) and a process for manufacturing a denitration catalyst for NH ₃ -SCR by supporting it on a tungsten oxide/titania material (Step 2) shows the flow chart of
Figure 2 shows the particle size analysis of the PSA (Particle Size Analyzer) before and after nano-milling of the nanoplatelet vanadium oxide slurry according to an embodiment of the present invention.
Figure 3 shows a TEM (Transmission Electron Microscopy) image analysis of the nanoplatelet vanadium oxide according to an embodiment of the present invention.
FIG. 4 shows an X-ray diffractometer (XRD) pattern of a denitration catalyst for NH ₃ -SCR in which nanoplatelet vanadium oxide is supported on a tungsten oxide/titania material according to an embodiment of the present invention.
5 shows a TEM image of a denitration catalyst for NH ₃ -SCR in which nanoplatelet vanadium oxide is supported on a tungsten oxide/titania material according to an embodiment of the present invention.
6 is a comparison of the denitration efficiency of the denitration catalyst for NH ₃ -SCR in which nanoplatelet vanadium oxide is supported on a tungsten oxide/titania material according to an embodiment of the present invention with the denitration efficiency of the denitration catalyst according to a comparative example. will be.

Best mode for carrying out the invention

Advantages and features of the present invention, and methods of achieving them, will become apparent with reference to the embodiments described below in detail. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, and only this embodiment allows the disclosure of the present invention to be complete, and common knowledge in the technical field to which the present invention belongs It is provided to fully inform the possessor of the scope of the invention, and the present invention is only defined by the scope of the claims.

Unless otherwise defined, all terms (including technical and scientific terms) used herein may be used with the meaning commonly understood by those of ordinary skill in the art to which the present invention belongs. In addition, terms defined in a commonly used dictionary are not to be interpreted ideally or excessively unless specifically defined explicitly.

Hereinafter, a denitration catalyst and a method for producing the same according to the present invention will be described in detail.

The denitration catalyst according to the present invention is characterized in that it comprises a nanoplatelet vanadium oxide supported on a titania-based carrier.

The denitration catalyst according to the present invention can be mainly used in the NH ₃ -SCR process for removing NOx generated in large combustion engines such as industrial boilers and coal-fired power plants.

In general, the catalyst operated in the NH ₃ -SCR denitration facility is economical due to an increase in consumption of an additional thermal energy source to reach the temperature at which the denitration efficiency is maximally activated. The denitration catalyst according to the present invention is a nanoplatelet vanadium Since the oxide is supported, it exhibits high denitration activity even in a low temperature region compared to the catalyst on which the amorphous vanadium oxide is supported, and thus has the effect of solving the problems of the conventional catalyst.

In the denitration catalyst of the present invention, the nanoplatelet vanadium oxide may be included in an amount of 0.1 to 5.0% by weight, preferably 0.5 to 4.0% by weight, based on the total weight of the denitration catalyst, and if it is less than the content range, vanadium oxide If the effect by the loading of is insufficient, and exceeds the above content range, not only N ₂ O is generated due to the higher content of vanadium oxide than necessary, but also an anchoring bond (VO-) Ti) does not increase any more, and the active area on the surface of the catalyst decreases due to vanadium oxide, which is undesirable because it causes deterioration of the denitration performance.

The vanadium oxide may be at least one selected from vanadium pentoxide (V ₂ O ₅ ), vanadium tetraoxide (V ₂ O ₄ ), vanadium trioxide (V ₂ O ₃ ), and the like, but is not limited thereto, and in particular Vanadium pentoxide (V ₂ O ₅ ) is preferred.

The particle size of the nanoplatelet vanadium oxide may be 20 to 500 nm, preferably 20 to 300 nm. If it is out of the above range, it cannot be sufficiently supported in the active space of the carrier or cannot sufficiently form an active area, and denitration at high temperature. During operation, the ammonia oxidation reaction of the catalyst is accelerated, which is undesirable. The above-mentioned particle size means an average value of the width and length of the plate-shaped body observed with a TEM electron microscope. When the particles in which the nanoplatelets are aggregated are observed with a particle size analyzer, a particle size of 100 to 600 nm is observed. The thickness of the nanoplatelet may be about 1 ~ 20nm.

The titania-based carrier may be a carrier in which an active metal compound is supported on a titania (TiO ₂ ) carrier, and the active metal compound includes manganese oxides, cerium oxides, tungsten oxides, and One or more selected from vanadium oxides, etc., but is not limited thereto, by preventing phase transition due to high temperature, expanding the active temperature range of the catalyst, inhibiting sintering, and improving physical and chemical properties such as increase in acid sites It is preferable to use tungsten oxide (WO ₃ ).

The titania-based carrier preferably has an anatase phase. Titania (TiO ₂ ) generally has three crystal structures of brookite, rutile, and anatase, titania having a crystal phase of anatase has chemical stability that does not readily react with sulfur compounds , has better catalytic activity compared to other phases.

The method for preparing a denitration catalyst according to the present invention may include the following steps.

1) preparing an anatase-phase titania carrier;

2) preparing a nanoplatelet vanadium oxide;

3) supporting the nanoplatelet vanadium oxide of step 2) on the titania-based carrier of step 1);

4) sintering the result of step 3) to prepare a denitration catalyst on which nanoplatelet vanadium oxide is supported.

In the method for preparing the denitration catalyst of the present invention, step 1) may include mixing the titanium precursor compound with distilled water and then hydrolyzing, followed by solid-liquid separation, washing with water, and neutralization.

The titanium precursor compound is one selected from titanyl sulfate (TiOSO ₄ ), titanium oxychloride (TiOCl ₂ ), titanium tetrachloride (TiCl ₄ ), titanium isopropoxide (TiOCH(CH ₃ ) ₂₄ ; TTIP), etc. It may be above, but is not limited thereto, and in particular TiOSO ₄ is preferred.

The hydrolysis may be performed at 70 to 100° C. for 10 to 20 hours, preferably at 90 to 100° C. for 15 to 18 hours for effective hydrolysis.

The neutralization may be performed by adjusting the pH to 7-8 by addition of a basic compound such as aqueous ammonia, and this neutralization treatment is also for effective loading of the active metal compound thereafter.

In the method for producing a denitration catalyst of the present invention, an active metal compound may be further supported on the titania support obtained after the neutralization in step 1). It plays a role of sintering and inhibiting phase transition. When the active metal compound is supported, it is preferably supported in an amount of 0.1 to 10% by weight, preferably 1 to 3% by weight, but when the supported amount is less than 0.1% by weight, the effect according to the loading of the active metal compound is insufficient. , when it exceeds 10% by weight, the cost for commercialization of the catalyst increases, which is not preferable because economic feasibility is lowered.

In the method for preparing the denitration catalyst of the present invention, step 2) may be performed by mixing the additive solution with the vanadium precursor compound solution, and then bead milling the powder obtained by drying and calcining.

The vanadium precursor compound may be at least one selected from ammonium metavanadate (NH ₄ VO ₃ ), vanadium oxytrichloride (VOCl ₃ ), vanadium sulfate (VOSO ₄ ), and the like, but is not limited thereto, particularly NH ₄ VO ₃ is preferred.

The additive may be at least one selected from polyvinyl alcohol (PVA), cellulose, ethylenediaminetetraacetic acid (EDTA), citric acid, ethylene glycol, and ammonium carbonate, but is not limited thereto, and PVA is particularly preferred. .

The additive serves to control the particle size of the vanadium oxide by reacting the vanadium ions with a chelate compound or a template material during the formation of the vanadium oxide in order to effectively prepare the nanoplatelet vanadium oxide.

A mixing weight ratio of the vanadium precursor compound solution and the additive solution may be 1:0.1 to 1.0, preferably 1:0.5 to 0.9. If the mixing weight ratio is out of the above range, agglomeration during heating due to the nature of the polymer additive reduces dispersibility, or when the polymer content increases, the catalytic activity decreases due to the residual polymer after calcination, making it difficult to manufacture powder. It may be undesirable.

The drying may be carried out at 80-100 ° C. for 10 to 24 hours, and the calcination may be performed at 400 to 800 ° C., preferably 450 to 600 ° C. for 1 to 10 hours, preferably 3 to 4 hours, The bead milling may be performed for 0.5 to 5 hours using zirconia beads.

In the method for preparing a denitration catalyst of the present invention, step 3) may be performed by adding the nanoplatelet vanadium oxide slurry to the titania-based carrier slurry and impregnating it.

The impregnation treatment may be performed under conditions of 150 to 200 mmbar, preferably 150 to 180 mmbar, most preferably 170 mmbar, 80 to 100° C., preferably 90° C. in a rotary vacuum distiller for effective impregnation.

In the method for preparing the denitration catalyst of the present invention, the calcination in step 4) may be performed at 400 to 600° C., preferably at 450 to 550° C. for 1 to 10 hours, preferably for 3 to 4 hours.

Modes for carrying out the invention

Hereinafter, the present invention will be described in more detail through Examples for the preparation of the nanoplatelet vanadium oxide-supported denitration catalyst according to the present invention and Comparative Examples for the preparation of the amorphous denitration catalyst. are not limited by

Example 1

According to the manufacturing process of the denitration catalyst shown in FIG. 1, a denitration catalyst supported with nanoplatelets V ₂ O ₅ was prepared as follows.

[Preparation step of tungsten oxide/titania carrier]

Titanyl sulfate (TiOSO ₄ ) The powder was mixed with distilled water and then hydrolyzed at 100° C. for 16 hours to prepare a titania (TiO ₂ ) slurry of 100-150 g/L. Using a high-speed centrifuge at 7000 rpm for 20 minutes, the TiO ₂ slurry and the solvent were separated, and distilled water was added in an amount three times the weight of the slurry to remove the sulfuric acid component in the slurry, and then mixed with a shaker. Solid-liquid separation was again performed for 20 minutes at 5000 rpm by high-speed centrifugation, and washed twice in total. To the washed slurry, distilled water of 3 times the weight was added, and then neutralized to pH 7-8 by adding aqueous ammonia to prepare a TiO ₂ sol. The tungsten precursor ((NH ₄ ) ₆ W ₁₂ O _39·X H ₂ O (Ammonium meta tungstate)) was quantified so that the tungsten oxide (WO ₃ ) was 3 wt% with respect to the TiO ₂ sol, and placed in 300 ml of distilled water for 1 hour. After dissolution by stirring, the TiO ₂ sol was mixed with the mixture and stirred for 2 hours to prepare a WO ₃ /TiO ₂ material in which WO ₃ was supported on a TiO ₂ carrier.

[Manufacturing step of nanoplatelet vananium oxide]

Nanoplatelet vanadium oxide (V ₂ O ₅ ) To prepare a slurry, NH ₄ VO ₃ (Ammonium metavanadate, purity: 99%) powder 5% by weight, H ₂ O ₂ (Hydrogen Peroxide, 30-35.5%) 30% by weight %, and 65% by weight of distilled water to prepare an orange solution, and then this solution was added to the additive solution mixed with distilled water so that PVA was 1% by weight as an additive. The resulting mixed solution was distilled under reduced pressure to evaporate the solvent to form a powder, dried in an oven at 100° C. for 12 hours, and then calcined at 450° C. under an air flow of 1 L/min for 4 hours. obtained after calcination The powder was added to absolute ethanol at a concentration of 4% by weight, and 1 kg of zirconia beads of 0.3Ø or less were added under a nano bead mill and milled for 4 hours to prepare a nanoplatelet V ₂ O ₅ .

[Nanoplatelet Bananium Oxide Supported Tungsten Oxide/Titania Catalyst Preparation Step]

The nanoplatelet V ₂ O ₅ slurry was added to the WO ₃ /TiO ₂ slurry so as to be 0.5 wt% based on the weight of TiO ₂ , and stirred for 2 hours. The obtained mixed slurry was put in a rotary vacuum distiller and impregnated under 170mmbar and 90°C conditions, and the obtained powder was heated to 500°C at 2°C/min and calcined for 4 hours in an air atmosphere, nanoplatelet V ₂ O ₅ A supported WO ₃ /TiO ₂ denitration catalyst was prepared.

Example 2

In the catalyst preparation step of Example 1, the nanoplatelet V ₂ O ₅ was added to the WO ₃ /TiO ₂ slurry in an amount of 1.0% by weight relative to the weight of TiO ₂ , and the impregnation treatment conditions in the rotary vacuum distiller were 150 mbar, 90° C. Nanoplatelet V ₂ O ₅ WO ₃ /TiO ₂ A denitration catalyst was prepared in the same manner as in Example 1 except that it was changed.

Example 3

In the catalyst preparation step of Example 1, in the same manner as in Example 1, except that the nanoplatelet V ₂ O ₅ was added to the WO ₃ /TiO ₂ slurry in an amount of 1.5% by weight based on the weight of TiO ₂ and supported, in the same manner as in Example 1. A plate-shaped body V ₂ O ₅ supported WO ₃ /TiO ₂ A catalyst was prepared.

Example 4

In the catalyst preparation step of Example 1, in the same manner as in Example 1, except that the nanoplatelet V ₂ O ₅ was added to the WO ₃ /TiO ₂ slurry in an amount of 2.0 wt% based on the weight of TiO ₂ and supported, in the same manner as in Example 1 A plate-shaped body V ₂ O ₅ supported WO ₃ /TiO ₂ A catalyst was prepared.

Example 5

In the catalyst preparation step of Example 1, in the same manner as in Example 1, except that the nanoplatelet V ₂ O ₅ was added to the WO ₃ /TiO ₂ slurry in an amount of 4.0% by weight based on the weight of TiO ₂ and supported. A plate-shaped body V ₂ O ₅ supported WO ₃ /TiO ₂ A catalyst was prepared.

Example 6

In the catalyst preparation step of Example 1, 10 nm silica sol was added in an amount of 10% by weight relative to the weight of TiO ₂ , and nanoplatelets V ₂ O ₅ were added and supported in an amount of 2% by weight relative to the weight of TiO ₂ , Example 1 Nanoplatelet V ₂ O ₅ was carried out in the same manner as WO ₃ /TiO ₂ A catalyst was prepared.

Comparative Example 1

In Example 1, a powdery vanadium oxide was prepared in the same manner as in the preparation of the nanoplatelet vananium oxide without performing the preparation of the carrier and the preparation of the catalyst.

Comparative Example 2

TiO ₂ The powder of NH ₄ VO ₃ (AMV, Ammonium metavanadate, purity: 99%) in an amount of 0.5% by weight relative to the weight of TiO 2 was added to distilled water heated to 60° C. and stirred until the temperature dropped to room temperature, To increase the solubility of AMV in distilled water, it was titrated to pH 2.5 with oxalic acid and stirred for 2 hours or more to prepare a vanadium solution.

In the catalyst preparation step of Example 1, 0.5 wt% of the vanadium solution obtained above was added to the WO ₃ /TiO ₂ slurry instead of the nanoplatelet V ₂ O ₅ and supported, and the calcination conditions in the rotary vacuum distiller were 150 mbar, Amorphous V ₂ O ₅ WO ₃ /TiO ₂ denitration catalyst was prepared in the same manner as in Example 1, except that it was changed to 90°C.

Comparative Example 3

In Comparative Example 2, an amorphous V ₂ O ₅ WO ₃ /TiO ₂ denitration catalyst was prepared in the same manner as in Comparative Example 1, except that 2.0 wt% of the vanadium solution was supported based on the weight of TiO ₂ . .

< Characteristic evaluation >

1. Characteristic evaluation of nanoplatelet V ₂ O ₅

The particle size of the nanoplatelet V 2 O 5 confirmed through PSA particle size analysis of the nanoplatelet V ₂ O ₅ prepared in Example 1 is shown in FIG. 2 , and the TEM image analysis result is shown in FIG. 3 .

2 and 3, it can be seen that the main particle size distribution of the nanoplatelet V ₂ O ₅ prepared according to the present invention is 200 to 300 nm in the slurry phase. In order to visually confirm this, TEM image analysis was performed, and it was confirmed that plate-shaped particles with a primary particle size of about 20 to 200 nm were distributed.

2. Characterization of the denitrification catalyst

The denitration characteristics of the denitration catalysts prepared in Examples 1 to 6 and Comparative Examples 1 to 3 were evaluated. It was evaluated as follows.

N ₂ gas was used as the balance gas, the concentrations of NOx and NH ₃ gas were fixed at 300 ppm, and the NOx and NH ₃ reaction ratio was 1:1. The oxygen concentration in the reaction gas was injected at 5 vol%, and the gas flow rate in the reactor was maintained at 300 cc/min. The catalyst fixed layer for removing NOx was maintained at a space velocity of 60,000 (hr ^-1 ), and the amount of catalyst was adjusted according to the space velocity to form a powder fixed layer using ceramic wool. The evaluation method is stabilizing until the expected concentration becomes constant by flowing N ₂ , O ₂ , NO, NH ₃ gas after mounting the catalyst on the reactor. As for the NOx removal efficiency, the NOx concentration change was observed at a temperature increase rate of 5 °C/min from 25 °C to 500 °C.

The evaluation results of the denitrification properties are shown in Table 1 below.

division Denitration catalyst composition (wt%) Denitrification properties TiO ₂ SiO ₂ WO ₃ Amorphous V ₂ O ₅ Nanoplatelet V ₂ O ₅ Denitrification conversion rate ¹⁾
(%) Maximum active temperature ²⁾
(℃ ^max ) Example 1 96.5 - 3.0 - 0.5 97 325 Example 2 96.0 - 3.0 - 1.0 94 329 Example 3 95.5 - 3.0 - 1.5 95 304 Example 4 95.0 - 3.0 - 2.0 95 300 Example 5 93.0 - 3.0 - 4.0 87 242 Example 6 85.0 10 3.0 - 2.0 94 275 Comparative Example 1 - 100 87 275 Comparative Example 2 96.5 - 3.0 0.5 - 99 383 Comparative Example 3 95.0 - 3.0 2.0 - 96 396

Note): 1) Denitration conversion rate: Measures the denitration efficiency up to 25~500℃, meaning the highest denitration efficiency among them. Maximum activation temperature: Measures the denitration efficiency from 25 to 500℃, and it means the temperature that shows the best denitration efficiency.

As shown in Table 1, the WO ₃ /TiO ₂ denitrification catalyst prepared in Examples according to the present invention in the form of nanoplatelets V ₂ O ₅ supported is amorphous V ₂ O prepared in Comparative Examples 2 and 3 It can be seen that the activation temperature is significantly lower than that of the ₅ -supported WO ₃ /TiO ₂ denitration catalyst.

On the other hand, in the case of the nanoplatelet vanadium oxide (V ₂ O ₅ ) of Comparative Example 1, the overall activation temperature moved to a low temperature region, but since there was no titania carrier having active pores, the vanadium oxide was supported on the titania-based carrier. Compared to the catalysts of Examples, the denitration efficiency showed a tendency to decrease. This is a result of a decrease in the active area of the catalyst surface due to a higher content of vanadium oxide than necessary, resulting in a decrease in the denitration performance.

As confirmed by the above results, the denitration catalyst according to the present invention is a low-temperature type denitration catalyst that shows high denitration efficiency at a low temperature range of 200 to 300°C, and is a process in the NH ₃ -SCR denitration process operated in a large combustion engine. By lowering the temperature range, energy consumption can be reduced, thereby improving economic efficiency. In addition, according to the present invention, by controlling the content of the nanoplatelet vanadium oxide, it is possible to prepare a denitration catalyst exhibiting activity in various temperature ranges within 200 ~ 300 ℃.

In addition, the WO ₃ /TiO ₂ denitrification catalyst prepared in Example 4 in the form of nanoplatelets prepared in the form of V ₂ O ₅ and the amorphous V ₂ O ₅ prepared in Comparative Example 2 WO ₃ /TiO ₂ denitration catalyst supported. The XRD diffraction pattern analysis results of FIG. 4 were compared and the TEM image analysis results were compared to FIG. 5 , and the thermal behavior analysis results were compared to FIG. 6 .

Through the XRD pattern analysis of FIG. 4 , the anatase phase was observed in the catalyst on which the nanoplatelet vanadium pentoxide was supported and the catalyst on which the amorphous vanadium pentoxide was supported, and the crystal or rutile phase transition of tungsten and vanadium oxide by high temperature was was not observed. In particular, no diffraction pattern was observed in the crystalline nanoplatelet vanadium pentoxide even in the catalyst on which the nanoplatelet vanadium pentoxide was supported, which is believed to be because the nanoplatelet thickness is dispersed in the order of several nanometers.

As a result of the TEM image analysis of FIG. 5 , it was confirmed that nanoplatelet vanadium pentoxide of 50 nm or less was supported around the spherical titania carrier and formed.

Through the evaluation of denitration efficiency by temperature as shown in FIG. 6, even with the same amount of supported amount, the temperature exhibiting the highest efficiency is different. It can be seen that the maximum activation temperature is exhibited at a relatively low temperature. For reference, the denitrification efficiency can be increased or decreased in the denitrification conversion temperature range (window) showing the denitrification characteristics depending on the experimental conditions, and in the present invention, a relative comparison was made under the experimental conditions suitable for denitration efficiency evaluation.

Claims (18)

A denitration catalyst comprising nanoplatelet vanadium oxide supported on a titania-based carrier. The denitration catalyst according to claim 1, wherein the nanoplatelet vanadium oxide is contained in an amount of 0.1 to 5% by weight based on the total weight of the denitration catalyst. According to claim 1, wherein the vanadium oxide is one selected from one selected from vanadium pentoxide (V ₂ O ₅ ), vanadium tetraoxide (V ₂ O ₄ ), and vanadium trioxide (V ₂ O ₃ ) more than a denitrification catalyst. The denitration catalyst according to claim 1, wherein the nanoplatelet vanadium oxide has a particle size of 20 to 500 nm. According to claim 1, wherein the titania-based carrier is an anatase phase alone or titania (TiO ₂ ) containing an anatase phase on the carrier tungsten oxide, manganese oxide, cerium oxide, molybdenum oxide, and at least one active metal selected from vanadium oxide A denitration catalyst that is a carrier on which the compound is supported. A method for producing a denitrification catalyst, comprising the following steps:
1) preparing a titania-based carrier comprising an anatase phase alone or an anatase phase;
2) preparing a nanoplatelet vanadium oxide;
3) supporting the nanoplatelet vanadium oxide of step 2) on the titania-based carrier of step 1);
4) sintering the result of step 3) to prepare a denitration catalyst on which nanoplatelet vanadium oxide is supported. [Claim 7] The method of claim 6, wherein step 1) comprises mixing the titanium precursor compound with distilled water and hydrolyzing the mixture, followed by solid-liquid separation, washing with water, and neutralization. The method of claim 7, wherein the titanium precursor compound is one or more selected from TiOSO ₄ , TiOCl ₂ , TiCl ₄ , and TiOCH(CH ₃ ) ₂₄ . The method of claim 7, wherein the hydrolysis is performed at 70-100° C. for 5 to 48 hours, and the neutralization is performed by adjusting the pH to 7-8. 7. The method of claim 6, wherein step 1) further comprises supporting one or more active metal compounds selected from tungsten oxide, manganese oxide, cerium oxide, molybdenum oxide and vanadium oxide on the titania carrier obtained after the neutralization. A method for producing a denitration catalyst. [Claim 7] The method of claim 6, wherein step 2) is performed by bead milling the powder obtained by mixing the additive solution with the vanadium precursor compound solution, drying and calcining. The method of claim 11, wherein the vanadium precursor compound is at least one selected from ammonium metavanadate (NH ₄ VO ₃ ), vanadium oxytrichloride (VOCl ₃ ), and vanadium sulfate (VOSO ₄ ). The method of claim 11, wherein the additive is at least one selected from polyvinyl alcohol (PVA), cellulose, ethylenediaminetetraacetic acid (EDTA), citric acid, ethylene glycol, and ammonium carbonate. The method of claim 11 , wherein the mixing weight ratio of the vanadium precursor compound solution and the additive solution is 1:0.1 to 1.0. 12. The method of claim 11, wherein the drying is performed at 80 ~ 100 ℃ 10 ~ 24 hours, the firing is performed at 400 ~ 800 ℃ 1 ~ 10 hours, the bead milling is performed using zirconia beads 0.5 ~ 5 hours A method for producing a denitration catalyst. The method according to claim 6, wherein step 3) is performed by adding the slurry of the nanoplatelet vanadium oxide to the slurry of the titania-based carrier and performing an impregnation treatment. The method of claim 16, wherein the impregnation treatment is performed under conditions of 150 to 200 mmbar and 80 to 100° C. in a rotary reduced pressure distiller. The method of claim 6, wherein the calcination in step 4) is performed at 400 to 600° C. for 1 to 10 hours.

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