阅读说明：本技术 具有优异的耐硫性的scr催化剂 (SCR catalyst having excellent sulfur resistance ) 是由 金峻佑 高东準 卞泳喆 金道喜 任钟泰 宋寅鹤 李滉镐 全世媛 于 2020-09-28 设计创作，主要内容包括：本发明涉及用于从废气中除去氮氧化物(NO-(x))的SCR催化剂,所述SCR催化剂包含：0.01重量％至70重量％的平均孔尺寸为或更大的沸石；25重量％至90重量％的二氧化钛(TiO-(2))；以及4重量％至10重量％的五氧化二钒(V-(2)O-(5))。根据本发明的SCR催化剂表现出优于常规SCR催化剂的在低温区域中的脱硝性能,具有改善的对硫化合物的耐受性,并且还具有优异的再生率。(The invention relates to a method for removing Nitrogen Oxides (NO) from exhaust gases x ) The SCR catalyst of (1), comprising: 0.01 to 70% by weight of a mean pore size of Or larger zeolites; 25 to 90 weight percent titanium dioxide (TiO) 2 ) (ii) a And 4 to 10% by weight of vanadium pentoxide (V) 2 O 5 ). The SCR catalyst according to the present invention exhibits denitration performance in a low temperature region superior to that of the conventional SCR catalyst, has improved tolerance to sulfur compounds, and also has an excellent regeneration rate.)

1. Method for removing Nitrogen Oxides (NO) from exhaust gas_x) The Selective Catalytic Reduction (SCR) catalyst of (a), the SCR catalyst comprising:

0.01 to 70 weight percent (wt%) of an average pore size ofOr larger zeolites;

25 to 90 weight percent titanium dioxide (TiO)₂) (ii) a And

4 to 10% by weight of vanadium pentoxide (V)₂O₅)。

2. The SCR catalyst of claim 1, wherein the exhaust gas comprises 30ppm or more of sulfur compounds.

3. The SCR catalyst of claim 1, wherein the temperature of the exhaust gas is in the range of 180 ℃ to 400 ℃.

4. The SCR catalyst of claim 1, further comprising:

0.01 to 15% by weight of tungsten trioxide (WO)₃)。

5. The SCR catalyst of claim 1, wherein the zeolite does not comprise a metal component.

6. The SCR catalyst of claim 1, wherein the zeolite has an aluminum to silicon weight ratio (Al: Si) of from 1:5 to 1: 30.

7. The SCR catalyst of claim 1, wherein the zeolite is at least one selected from the group consisting of: Zeolite-Y, ZSM-5 zeolite, AEL zeolite, AFI zeolite, AFO zeolite, AFR zeolite, BEA zeolite, HEU zeolite, MFI zeolite, MOR zeolite, MEL zeolite, and MTW zeolite.

8. The SCR catalyst of claim 1, wherein the conversion of nitrogen oxides in the exhaust gas is from 40% to 96% over a temperature range of from 200 ℃ to 250 ℃.

9. The SCR catalyst of claim 1, regenerated at a temperature range of 240 ℃ or higher.

Technical Field

The present disclosure relates to Selective Catalytic Reduction (SCR) catalysts, and more particularly, to SCR catalysts capable of removing nitrogen oxides from exhaust gases containing high concentrations of sulfur compounds.

Background

In a boiler or combustion apparatus using coal as a raw material, such as a combustion device, a gas turbine, or an internal combustion engine, the raw material is exposed to a high temperature and burned to generate a large amount of gas. Such exhaust gases may contain various harmful gases. The exhaust gas composition may contain nitrogen, oxygen, carbon dioxide, and water generated in a general combustion process, and may contain nitrogen oxides, sulfur oxides, hydrocarbons, carbon monoxide, and halogen compounds as harmful substances. In the recent situation where environmental problems have arisen in society with respect to fine dust, the fine dust and acid rain are caused by nitrogen oxides and sulfur oxides.

Harmful substances should be removed to protect the environment. Therefore, the exhaust gas is desulfurized through a wet method or a dry method, and then denitrated through a Selective Catalytic Reduction (SCR) method to be discharged into the air.

In SCR technology for denitration treatment (e.g., for reducing nitrogen oxides), a burner is used to raise the temperature to match the catalyst operating temperature, and thus may incur high fuel costs. Therefore, research on developing a low-temperature operating SCR catalyst to reduce fuel costs has been actively conducted, and a catalyst operating at about 200 ℃ has been applied.

The SCR technology uses ammonia as a reducing agent, and a reaction between ammonia and nitrogen oxides of an SCR catalyst bed may be performed according to the following reaction formula 1.

[ reaction formula 1]

4NO+4NH₃+O₂→4N₂+6H₂O

2NO₂+4NH₃+O₂→3N₂+6H₂O

NO+NO₂+2NH₃→2N₂+3H₂O

In the above reaction, ammonia that does not participate in the reduction of nitrogen oxides reacts with sulfur oxides in the exhaust gas to produce ammonium salts. In the ammonium salt, Ammonium Bisulfate (ABS) exists in a liquid phase at a temperature of about 280 ℃ (SCR operating temperature) and fills pores of the catalyst, thereby deteriorating the performance of the catalyst.

Disclosure of Invention

Technical problem

An aspect of the present disclosure is to provide a catalyst having excellent resistance to catalyst deactivation caused by ammonia-sulfur compounds (AS and ABS) formed when an SCR catalyst operates in a low temperature region.

It is an aspect of the present disclosure to provide a catalyst having excellent resistance to catalyst deactivation caused by ammonia-sulfur compounds formed when the catalyst is operated in a high-temperature region and ammonia-sulfur compounds formed when the catalyst is operated in a low-temperature region.

Technical scheme

According to one aspect of the present disclosure, for removing Nitrogen Oxides (NO) from exhaust gas_x) Comprises: 0.01 to 70 weight percent (wt%) of an average pore size ofOr larger zeolites; 25 to 90 weight percent titanium dioxide (TiO)₂) (ii) a And 4 to 10% by weight of vanadium pentoxide (V)₂O₅)。

The exhaust gas may contain 30ppm or more of sulfur compounds.

The temperature of the exhaust gas may be in the range of 180 ℃ to 400 ℃.

The SCR catalyst can also comprise 0.01 to 15 wt% tungsten trioxide (WO)₃)。

The zeolite may not contain a metal component.

The zeolite can have an aluminum to silicon (Al: Si) weight ratio of 1:5 to 1: 50.

The zeolite may be at least one selected from the group consisting of: Zeolite-Y, ZSM-5 zeolite, AEL zeolite, AFI zeolite, AFO zeolite, AFR zeolite, BEA zeolite, HEU zeolite, MFI zeolite, MOR zeolite, MEL zeolite, and MTW zeolite.

The conversion of nitrogen oxides in the exhaust gas may be 40% to 96% in the temperature range of 200 ℃ to 250 ℃.

The SCR catalyst can be regenerated at a temperature in the range of 240 ℃ or higher.

Advantageous effects

As described above, the SCR catalyst according to the present disclosure may exhibit excellent denitration performance in a low temperature region, and may have improved tolerance to sulfur compounds and excellent regeneration rate, as compared to a conventional SCR catalyst.

Drawings

Fig. 1 is a schematic illustration of an SCR catalyst according to an example embodiment of the disclosure.

Fig. 2 shows the results of the nitrogen oxide conversion experiments of the SCR catalysts according to preparation examples 1 to 4 and comparative preparation example 1.

Fig. 3 shows the results of the resistance evaluation experiment of the SCR catalysts according to inventive example 1, comparative example 1, and comparative example 2 to sulfur compounds.

Fig. 4 shows the results of the evaluation experiment of the resistance of the SCR catalysts according to inventive example 1, inventive example 2, comparative example 1, and comparative example 3 to sulfur compounds.

Fig. 5 shows the results of the evaluation experiment of the resistance of the SCR catalysts according to inventive example 3, inventive example 4, comparative example 4, and comparative example 5 to sulfur compounds.

Fig. 6 shows the results of the resistance evaluation experiment of the SCR catalyst and the commercial catalyst according to invention example 2 against sulfur compounds.

Detailed Description

In the following description, example embodiments of the present disclosure will be described. However, the embodiments of the present disclosure may be modified in various ways, and the scope of the present disclosure may not be limited to the embodiments described below. In addition, these embodiments can be provided to more fully describe the disclosure to those of ordinary skill in the art.

The present disclosure relates to an SCR catalyst having excellent sulfur resistance.

When applying SCR technology to remove nitrogen oxides from exhaust gases, Sulfur Oxides (SO) in the exhaust gases pass through_x) And use ofAmmonium Sulfate (AS) and Ammonium Bisulfate (ABS) (ammonium salts) produced by the reaction of ammonia AS a reducing agent may physically cover the catalyst or may fill the pores without losing active sites, which is referred to AS contamination. AS and ABS may be produced by the following equations 2 and 3.

[ reaction formula 2]

SO₂+1/2O₂→SO₃

SO₃+H₂O→H₂SO₄

2NH₃+H₂SO₄→(NH₄)₂SO₄

[ reaction formula 3]

NH₃+SO₃+H₂O→(NH₄)HSO₄

(NH₄)₂SO₄→(NH₄)HSO₄+NH₃

AS and ABS, each having a solid form at room temperature, may melt at a temperature of about 147 ℃ to cause phase change, may exist in a liquid state at a temperature of 270 ℃ to 280 ℃, and may fill pores of the catalyst. For this reason, the active sites of the catalyst disposed in the pores may be lost, resulting in deactivation. However, when the ABS is exposed to a high temperature of 380 ℃ or more, the ABS may be decomposed.

In addition, poisoning may occur in which the active sites of the catalyst are sulfided with sulfur oxides. More specifically, sulfur oxides SO contained in the exhaust gas₂And SO₃It is possible that the carrier or active metal adsorbed to the catalyst will be present in the form of a metal sulphide or sulphate, thereby reducing the lifetime of the catalyst, which is known as poisoning. Such contamination and poisoning may occur simultaneously. Therefore, particularly in exhaust gas containing a large amount of sulfur oxides therein, the life of the SCR catalyst may be significantly reduced. Further, when a zeolite-containing catalyst is used to remove nitrogen oxides in exhaust gas, the zeolite may be weakened as the content of sulfur compounds increases. Therefore, during the removal of nitrogen oxides from exhaust gas containing a large amount of sulfur compounds therein, a zeolite-containing catalyst may not be used。

Fig. 1 is a schematic illustration of an SCR catalyst according to an example embodiment of the disclosure. Hereinafter, the present disclosure will be described in detail with reference to fig. 1.

According to one aspect of the present disclosure, a method for removing Nitrogen Oxides (NO) from exhaust gas is provided_x) The SCR catalyst of (1). The SCR catalyst can comprise an average pore size of 0.01 weight percent (wt%) to 70 wt% (wt%)Or larger zeolite, 25 to 90 wt% titanium dioxide (TiO)₂) And 4 to 10% by weight of vanadium pentoxide (V)₂O₅)。

Referring to fig. 1, an SCR catalyst according to the present disclosure may be a catalyst having V-containing mixed therein₂O₅Of TiO 2₂(V₂O₅/TiO₂) And a catalyst for zeolite. V₂O₅/TiO₂Nitrogen oxides may be reduced by SCR reactions, and zeolites may be preferentially inserted from SO using acid sites and pores_xSulfur compounds (AS, ABS, etc.). Due to V₂O₅/TiO₂The SCR performance can be maintained relatively less deactivated by sulfur compounds (AS, ABS, etc.). In addition, zeolites can play a role not only in collecting sulfur compounds, but also in participating in the regeneration of the catalyst at high temperatures to bring it back to its original activity.

An SCR catalyst according to the present disclosure may include 25 to 90 wt% titanium dioxide (TiO) based on the total weight of the SCR catalyst₂) Specifically, 40 to 70% by weight of titanium dioxide (TiO)₂). When titanium dioxide (TiO)₂) Can impregnate vanadium pentoxide (V) when the content of (C) is less than 25 wt%₂O₅) The amount of carrier (active ingredient) may be reduced, resulting in reduced performance. When titanium dioxide (TiO)₂) At a content of more than 90 wt%, the amount of zeolite may be reduced, resulting in poor tolerance to sulfur compounds.

Further, the SCR catalyst according to the present disclosure may include 4 to 10 wt% of vanadium pentoxide (V) based on the total weight of the SCR catalyst₂O₅) Specifically, 4 to 7% by weight of vanadium pentoxide (V)₂O₅). When vanadium pentoxide (V)₂O₅) When the content of (B) is less than 4% by weight, vanadium pentoxide (V)₂O₅) The amount of (active ingredient) may be low, so that denitration (NO removal) may occur_x) The performance is reduced. When vanadium pentoxide (V)₂O₅) At more than 10% by weight, the dispersibility of the active metal may be due to an excessive amount of vanadium pentoxide (V)₂O₅) And decreases, resulting in performance degradation.

Further, the SCR catalyst according to the present disclosure may include 0.01 to 70 wt% of the zeolite, specifically, 20 to 40 wt% of the zeolite, based on the total weight of the SCR catalyst. When the content of the zeolite is less than 0.01 wt%, the resistance to sulfur compounds may be reduced. When the content of zeolite is more than 70% by weight, V is contained₂O₅/TiO₂The total amount of SCR active ingredient(s) is reduced and performance degradation may occur.

The average pore size of the zeolite may be specified asOr larger, and further specificallyToWhen the average pore size of the zeolite is less thanWhen the pore size is so small that the AS, ABS, etc. causing catalyst deactivation may not pass through the zeolite. Therefore, the sulfur resistance may not be ensured.

The weight ratio of aluminum to silicon (Al: Si) of the zeolite capable of securing sulfur resistance may be changed depending on the type of zeoliteAlternatively, it may be specifically 1:5 to 1:50, and further specifically 1:5 to 1: 30. When the weight ratio is outside the above range, the sulfur resistance may be due to SO₂Decrease in adsorption sites or acid sites of AS, ABS, etc.

According to one exemplary embodiment, in particular, the zeolite may be a zeolite that does not include a metal component. In the present disclosure, the term "metal component" refers to a component including iron, cobalt, nickel, copper, chromium, zinc, manganese, and the like. In zeolites comprising a metal component, the metal (active site) may be reacted with SO₂Etc. to be converted into sulfate with significant ease. In the present disclosure, by using a zeolite to which no metal component is added, the generation of metal sulfate can be prevented, thereby suppressing the performance degradation of the zeolite. Furthermore, SO-derived sources may be preferentially adsorbed₂To allow V, sulfur compounds (AS, ABS, etc.)₂O₅/TiO₂The denitration performance is kept.

The zeolite suitable for use in the present disclosure is not limited, but may be at least one selected from the group consisting of: such as zeolite-Y, ZSM-5 zeolite, AEL zeolite, AFI zeolite, AFO zeolite, AFR zeolite, BEA zeolite, HEU zeolite, MFI zeolite, MOR zeolite, MEL zeolite, and MTW zeolite, and may be specifically zeolite-Y.

The SCR catalyst according to the present disclosure may be a promoter, and may comprise 0.01 to 15 wt% of tungsten trioxide based on the total weight of the SCR catalyst (WO)₃) Specifically 1 to 10% by weight of tungsten trioxide (WO)₃). When tungstic oxide (WO)₃) When the content of (b) is less than 0.01 wt%, the low-temperature SCR performance may be degraded. When tungstic oxide (WO)₃) When the content of (b) is more than 15% by weight, the dispersibility of tungsten may be lowered, thereby deteriorating the oxidation property.

Tungsten has excellent oxidation properties, allowing improved catalyst performance at low temperatures. However, SO is formed by tungsten₂By oxidation to SO₃Therefore tungsten is not commonly used in commercial catalysts. For example, Ammonium Bisulfate (ABS), the most important poisoning species in deactivating SCR catalysts, is derived from SO₃. In the present disclosure, due to formationABS can be preferentially adsorbed to zeolites, so ABS can be free of V₂O₅/TiO₂Poisoning. Therefore, the SCR catalyst can maintain performance, and thus even when the SCR catalyst contains tungsten, can contribute to improvement of only low-temperature performance without being subjected to SO₂The effect of oxidation.

An SCR catalyst according to the present disclosure may be used to remove nitrogen oxides from exhaust gas containing 30ppm or more of sulfur compounds. As described above, zeolites can be used to remove nitrogen oxides from diesel exhaust gases having a sulfur content of typically 10ppm or less, but zeolites cannot be used to remove nitrogen oxides from exhaust gases containing 30ppm or more of sulfur. However, the present disclosure may result in an optimum content of zeolite, an average pore size of the zeolite, and an aluminum to silicon (Al: Si) weight ratio to provide an SCR catalyst capable of removing nitrogen oxides from exhaust gas containing 30ppm or more of sulfur.

The exhaust gas containing 30ppm or more of sulfur compounds is not limited, but may be, for example, exhaust gas generated during a sintering process of a steel mill, exhaust gas of a thermoelectric power plant, exhaust gas of an incinerator, exhaust gas of a marine engine, and the like. The SCR catalyst according to the present disclosure may be suitably used for exhaust gas.

The temperature of the exhaust gas may be 180 ℃ to 400 ℃. In other words, the operating temperature of the catalyst according to the present disclosure may be 180 ℃ to 400 ℃. Usually based on V₂O₅/TiO₂The operating temperature of the SCR catalyst of (1) is 310 to 340 ℃, but exhaust gas post-treatment equipment such as a steel mill sintering device or a ship is required to have excellent performance in a temperature range of 200 to 250 ℃. As described above, in the present disclosure, in the region of 180 ℃ to 280 ℃ where ABS or the like exists in a liquid state, ABS or the like is preferentially adsorbed in the pores of zeolite, so that the SCR catalyst activity can be maintained.

The SCR catalyst according to the present disclosure may exhibit an excellent effect in which the conversion rate of nitrogen oxides in exhaust gas is 40% to 96% in a temperature range of 200 ℃ to 250 ℃. In addition, in the temperature range of 240 ℃ or more, ABS adsorbed in zeolite pores may be gradually decomposed by zeolite acid sites, and catalytic activity may be regenerated.

EMBODIMENTS FOR CARRYING OUT THE INVENTION

Hereinafter, the present disclosure will be described in more detail by examples. It should be noted, however, that the following examples are for illustrative purposes only and are not intended to limit the scope of the present disclosure. The scope of the present disclosure may be determined by what is described in the claims and what can reasonably be inferred therefrom.

Detailed description of the preferred embodiments

1. According to V₂O₅Evaluation of the conversion of nitrogen oxides of content

Preparation example 1

Adding TiO into the mixture₂Used as the support, a solution in which ammonium metavanadate was dissolved in oxalic acid was prepared using an impregnation method and dried, and then sintered at a temperature of 500 ℃ for 4 hours to prepare a catalyst containing 4% by weight of V₂O₅And 96% by weight of TiO₂The catalyst of (1).

Preparation example 2

A catalyst was prepared in the same manner as in preparation example 1, except that V was₂O₅The content of (B) was controlled to 5% by weight.

Preparation example 3

A catalyst was prepared in the same manner as in preparation example 1, except that V was₂O₅The content of (B) was controlled to 7% by weight.

Preparation example 4

A catalyst was prepared in the same manner as in preparation example 1, except that V was₂O₅The content of (B) was controlled to 10% by weight.

Comparative preparation example

A catalyst was prepared in the same manner as in preparation example 1, except that V was₂O₅The content of (B) was controlled to 3% by weight.

The catalysts of preparation examples 1 to 4 and comparative preparation example 1 had 100,000 hours^-1And applying it to a solution having a NH content of 500ppm₃500ppm of NO, 10% of O₂5% of CO₂10% of H₂O and the balance of N₂The composition of (a). In addition, nitrogen and oxygen were measuredThe conversion of the compound is shown in figure 2.

Referring to FIG. 2, the composition according to the comparative preparation example contains 3% V₂O₅The catalyst of (A) shows a low nitrogen oxide conversion of 20 to 70% in the region of 200 to 250 ℃ and when V₂O₅The conversion of nitrogen oxides at temperatures of from 200 ℃ to 250 ℃ increases with increasing content of (a). The catalyst according to preparation example 3 showed a high conversion of nitrogen oxides of 75% at a temperature of 200 ℃ and 96% at a temperature of 250 ℃ while V was₂O₅When the content of (b) is increased to more than 10%, the performance is rather deteriorated.

2. Evaluation of resistance to sulfur compounds

The evaluation of sulfur resistance was carried out using the catalyst according to preparation example 3. Specifically, the composition is prepared by mixing 7 wt% of WO₃The catalyst prepared by mixing with the catalyst according to preparation example 3 is represented as comparative example 1, and 7 wt% of WO₃And 30% by weight of the total amount of ZSM-5 zeolite was mixed with the catalyst according to preparation example 3 to prepare a catalyst, which was denoted as invention example 1, and which was prepared by mixing 7% by weight of WO₃And 30% by total weight of silica was mixed with the catalyst according to preparation example 3 to prepare a catalyst, which is expressed as comparative example 2. Hereinafter, a process of evaluating the resistance to sulfur compounds will be described.

To evaluate the denitration performance at a temperature of 200 ℃ and to deactivate the catalyst, NH was increased at the same temperature₃In combination with addition of SO₂To form a sulfur compound. The resistance to sulfur compounds was evaluated by: deactivation was performed for 24 hours, denitration performance was evaluated at the same temperature, and the catalyst was exposed to various temperatures to evaluate whether the catalyst was regenerated. Each regeneration temperature was divided into 270 ℃ (normal operating temperature during sintering), 310 ℃ (maximum temperature that can be increased), and 380 ℃ (temperature at which ABS decomposes). The process conditions for evaluating the resistance to sulfur compounds are summarized and listed in table 1, and the experimental results of the resistance to sulfur compounds of inventive example 1, comparative example 1 and comparative example 2 are listed in tables 2 and 3.

TABLE 1

TABLE 2

Referring to table 2 and fig. 3, the initial performance of the catalyst according to comparative example 1 showed a nitrogen oxide conversion rate of about 90%, but its performance was degraded as the deactivation progressed, so that the nitrogen oxide conversion rate was reduced to about 75%. The catalyst was then regenerated at each temperature and the performance recovered by 2% at a temperature of 270 ℃. As the temperature increased, the performance recovered and the catalyst was 100% regenerated at a temperature of 380 ℃, and at a temperature of 310 ℃ the regeneration rate was confirmed to be relatively low. On the other hand, the initial performance of the catalyst according to inventive example 1 was about 95%, and its performance only decreased by about 5% during deactivation. As mentioned above, it is believed that the zeolite preferentially adsorbs AS and ABS such that V₂O₅/TiO₂The performance of (2) is maintained. Then, the catalyst was regenerated at each temperature. The catalyst showed high regeneration at a temperature of 310 ℃ and almost 100% regeneration at a temperature of 380 ℃.

Similar to the catalyst according to comparative example 1, the catalyst according to comparative example 2 suffered from a performance decline in the deactivated portion, and after regeneration at a temperature of 380 ℃, the performance slightly increased.

3. Evaluation of the resistance to sulfur compounds according to the average pore size of the zeolite

Except that comparative example 1 (containing no zeolite) and inventive example 1 (containing an average pore size ofBy mixing 30% of the total weight of the catalyst with an average pore size ofThe catalyst prepared by mixing the zeolite Y of (a) with the catalyst according to preparation example 3 was represented as invention example 2, and the average pore size by 30% of the total weight was made to beThe catalyst prepared by mixing the CHA zeolite of (a) with the catalyst according to preparation example 3 is represented as comparative example 3. Then, evaluation of the resistance to sulfur compounds according to the average pore size of zeolite was performed in the same manner as described above, and the results of the evaluation are shown in fig. 4.

Referring to fig. 4, the order of excellent tolerability is as follows: comprising an average pore size of"inventive example 2" of Y Zeolite ">Comprising an average pore size of"inventive example 1" of Zeolite ZSM-5 ">"comparative example 1" containing no zeolite ">Comprising an average pore size of"comparative example 3" of CHA zeolite (a). In the case of CHA, it is believed that AS and ABS (deactivated material) cannot pass through due to the significantly small pores.

4. Evaluation of the resistance to sulphur compounds according to the content of zeolite Si/Al

Catalysts were prepared using Y zeolite having various Si/Al contents, evaluation of resistance to sulfur compounds according to the Si/Al content of zeolite was performed in the same manner as described above, and the results of the evaluation are shown in fig. 5. The compositions and Si/Al weight ratios of inventive examples 3 and 4 and comparative examples 3 and 4 are as follows (inventive example 3: 5 wt.% V)₂O₅7% by weight of WO₃59.5% by weight of TiO₂30 wt% Y zeolite, and Si/Al ═ 5, inventive example 4: 5% by weight of V₂O₅7% by weight of WO₃59.5 in weightAmount% of TiO₂30% by weight of Y zeolite, and Si/Al ═ 12, comparative example 4: 5% by weight of V₂O₅7% by weight of WO₃59.5% by weight of TiO₂And 30 wt% silica, comparative example 5: 5% by weight of V₂O₅7% by weight of WO₃59.5% by weight of TiO₂30 wt% Y zeolite, and Si/Al 60).

Referring to fig. 5, in the case of having Si: Al contents of invention examples 3 and 4, the resistance to sulfur compounds is excellent, and a high Si/Al ratio of 60 tends to lower the resistance. It was thus confirmed that the amount of Al was reduced, and therefore SO₂Or adsorption sites of AS and ABS are reduced, thereby reducing the tolerance.

5. Evaluation of resistance to sulfur compounds using commercial catalysts

The catalyst according to invention example 2 and the commercial catalyst (5 wt% of V) were evaluated using exhaust gas of an actual steel-making sintering furnace₂O₅And 95% by weight of TiO₂) The tolerance of (2). The catalyst used had dimensions of 150 x 600 (width x length x height) and was typically prepared to have commercial catalyst unit module dimensions and evaluated for tolerance. The exhaust gas composition may vary depending on the sintering furnace working environment, but typically contains 160ppm to 250ppm NO, 250ppm NH₃50ppm to 100ppm SO₂15% of O₂6% CO₂10% of H₂O, and various impurities. The flow rate used in the catalyst evaluation was 100Nm³Average value per hour, and space velocity of 5,500 hours^-1To 6,000 hours^-1. The durability evaluation was performed using the catalyst according to invention example 2 and a commercial catalyst under the conditions listed in table 3, and the results of the evaluation are shown in fig. 6.

TABLE 3

	Performance evaluation	Deactivation of the enzyme	Performance evaluation	Regeneration	Performance evaluation
						Temperature [ deg.C ]]	220	180	220	280	220
Time [ hour]	2	120	2	72	72

Referring to fig. 6, both the catalyst according to inventive example 2 and the commercial catalyst showed similar performance of about 90% at a temperature of 220 ℃. The deactivation was carried out at a temperature of 180 c at which AS and ABS are well formed for 120 hours to accelerate the deactivation, and the performance at a temperature of 220 c was evaluated every 30 to 50 hours. In an accelerated evaluation of deactivation by exposure to 180 ℃, the following decline in performance of each catalyst after about 50 hours of exposure occurred: the performance of the commercial catalyst was reduced by 50% from 90% (initial performance of each catalyst) to 40%, and the performance of the catalyst according to inventive example 2 was reduced by about 35% from 90% to about 55%. After 130 hours of exposure, the commercial catalyst showed 20% or less performance and the catalyst according to invention example 2 showed 30% performance. Further, when evaluating the performance at a temperature of 220 ℃ during deactivation, the endurance times during which the performance satisfying 70% of the gas emission regulations was maintained were compared with each other. The tolerance time for the commercial catalyst was about 70 hours and the tolerance time for the catalyst according to inventive example 2 was about 100 hours. Thus, it was determined that the catalyst according to inventive example 2 was 30% better tolerant than the catalyst. On the other hand, the regeneration performance was evaluated by exposing the corresponding catalyst to a temperature of 280 ℃ under the same inlet conditions. At this temperature, the commercial catalyst exhibited a denitration performance of 95%, and the catalyst according to inventive example 2 exhibited a denitration performance of 92%. After 72 hours of catalyst regeneration, each catalyst was 100% regenerated at a temperature of 220 ℃ and its performance was maintained for 72 hours. In previous laboratory evaluations, the catalyst recovered 100% only at a temperature of 380 ℃, but recovered even at a temperature of 280 ℃ under actual exhaust gas exposure conditions.

The catalyst from which ABS was removed while passing through the regeneration section was evaluated at a temperature of 220 ℃ for about 50 hours, and both catalysts maintained 90% performance. Both catalysts were then subjected to accelerated deactivation evaluations at a temperature of 180 ℃. At a temperature of 180 ℃, the commercial catalyst deactivated significantly rapidly, but the catalyst according to invention example 2 showed more than twice the tolerance. Furthermore, the performance of the catalyst according to inventive example 2 at a temperature of 220 ℃ continued to be maintained at 70% or more.

Although the exemplary embodiments in the present disclosure have been described in detail, the claims of the present disclosure are not limited thereto, and it will be apparent to those skilled in the art that various modifications and changes may be made without departing from the technical concept of the present disclosure described in the claims.