Alumin-rich mel zeolite catalyst, its preparation method and application

Abstract

The application belongs to the field of catalytic denitration, and particularly relates to an aluminum-rich MEL zeolite catalyst and a preparation method and application thereof. The preparation method of the aluminum-rich MEL zeolite catalyst comprises the following steps: 1) adding raw materials and seeds; 2) performing pre-crystallization reaction, then crystallizing by increasing temperature, and calcining to obtain MEL zeolite molecular sieve; and 3) obtaining the aluminum-rich MEL zeolite catalyst by ion exchange of the MEL zeolite molecular sieve. The technical scheme of the application prepares the aluminum-rich MEL zeolite molecular sieve by using the seed auxiliary method. In the synthesis process, by optimizing the preparation method and the molar ratio of raw materials, increasing pre-crystallization, and adjusting the temperature and time of crystallization, the pre-crystallization stage promotes the nucleation of the molecular sieve, ensures more aluminum to enter the zeolite framework in the crystallization stage, so that the zeolite with a silicon-aluminum ratio of 8-25 is crystallized, and the MEL molecular sieve rich in acid sites is further prepared.

Description

Technical Field

[0001] This invention belongs to the field of catalytic denitrification, specifically relating to an aluminum-rich MEL zeolite catalyst, its preparation method, and its application. Background Technology

[0002] Globally, nitrogen oxides (NOx) from both mobile and stationary sources have caused serious harm to the ecological environment and human health. Currently, selective catalytic reduction (SCR) is the most widely used and mature technology for treating NOx emissions. It utilizes a reducing agent (ammonia or ammonia produced from the decomposition of urea) to selectively react with NOx under the action of a catalyst to produce water and nitrogen. However, when treating exhaust gases from vehicles or industrial waste gases containing sulfur-containing fuels, this technology generates a certain amount of sulfur dioxide under oxygen-enriched conditions. This sulfur dioxide then reacts with ammonia to form ammonium sulfate. Ammonium sulfate easily adheres to surfaces, not only easily covering the catalyst surface and causing deactivation, but also causing corrosion of pipelines and equipment. Although a large amount of research has been conducted on the development of sulfur dioxide-resistant NH3-SCR catalysts, as long as NH3 is used as a reducing agent, problems such as catalyst deactivation and pipeline blockage caused by ammonium sulfate cannot be avoided in the treatment of NOx from sulfur-containing fuels.

[0003] Methanol does not readily react with sulfur oxides to form precipitates similar to ammonium sulfate. Therefore, the CH3OH-SCR technology, which uses methanol instead of ammonia for the selective catalytic reduction of nitrogen oxides, has emerged. Compared to NH3-SCR, this technology avoids catalyst deactivation and pipeline blockage, and can also reduce investment in SCR units in methanol-fueled applications. Non-patent literature [App l. Cata lB-Environ., 2016, 180, 291–300, Cata l. Today., 2015, 258, 454–460] prepared Ag / Al2O3 catalysts with a 60% NOx conversion rate at 250°C, but produced approximately 30% N2O byproducts. Non-patent literature [J. Cata l. 2019, 377, 480–493] used methanol as a reducing agent, comparing it with LaFe... 0.8 Cu 0.2 Catalytic performance of O3 perovskite and Ag / Al2O3, LaFe 0.8 Cu 0.2 O3 perovskite exhibits excellent performance above 400℃, but its activity remains relatively poor below 300℃. Regarding the application of molecular sieves in CH3OH-SCR, non-patent literature [Cata l. Today., 2020, 355, 443–449] using commercial HZSM-5 found that it achieves approximately 60% NOx conversion at 300℃; however, its temperature window remains relatively narrow and cannot meet the needs of practical industrial flue gas applications.

[0004] The FER zeolite catalyst prepared by patent CN 114206495 B exhibits a NOx conversion rate of over 80% and N2 selectivity at 250–350 °C, demonstrating good CH3OH-SCR catalytic performance. However, the synthesis of specific FER topologies still requires expensive template agents. Therefore, it is of great significance to develop other zeolite catalysts that have excellent CH3OH-SCR performance and are easy to synthesize.

[0005] MEL is a type of zeolite molecular sieve with a unique structure and good acidity, and it has great potential application value for the selective catalytic reduction of NOx by methanol (CH3OH-SCR). Its structural characteristics are: (1) It has a large micropore volume (approximately 0.3 cm). 3 (2) It has a ten-membered ring (10MR) pore opening with a mesopore and a two-dimensional cross-shaped straight channel; (3) The framework structure can be aluminosilicate or borosilicate. Currently synthesized MEL zeolites usually use external organic templates as structure directing agents. Patents CN 102897788 B and CN 110203946A provide methods for preparing MEL zeolites, but the synthesized MEL molecular sieves still have a Si / Al ratio higher than 25 and the synthesis time is long, which makes it difficult to apply to the CH3OH-SCR scenario. Therefore, selecting a suitable organic structure directing agent and preparation method to synthesize MEL zeolite catalysts with a low Si / Al ratio is of great significance for protecting the environment and promoting the rapid development of green industries. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide an aluminum-rich MEL zeolite catalyst, its preparation method, and its application.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A method for preparing an aluminum-rich MEL zeolite catalyst includes the following steps:

[0009] 1) Dissolve alkali metal source and aluminum source in deionized water, add template agent and silicon source, add seed crystals to the well-stirred mixture, and after aging, load into the reactor; 2) After pre-crystallization reaction, heat to crystallize, and the obtained product is filtered, washed, dried and calcined to obtain MEL zeolite molecular sieve; 3) Obtain aluminum-rich MEL zeolite catalyst by ion exchange of MEL zeolite molecular sieve.

[0010] The seed crystal is either S-2 seed crystal or ZSM-11 seed crystal.

[0011] The S-2 seed crystals are prepared by mixing silicon source, template agent and deionized water and then carrying out a hydrothermal reaction in an oven at 140-180℃ for 12-48 hours. The resulting suspension is the S-2 seed crystal. The molar ratio of silicon source, template agent and deionized water is 1:0.25-0.45:20-30.

[0012] ZSM-11 seed crystals are prepared as follows: an alkali metal source and an aluminum source are dissolved in deionized water, a template agent and a silicon source are added, and a hydrothermal reaction is carried out in an oven at 140-180℃ for 12-48 hours. The resulting product is filtered, washed, dried and calcined to obtain ZSM-11 seed crystals. The molar ratio of silicon source, aluminum source, template agent, alkali metal source and deionized water is 1:(0.02-0.08):(0.15-0.45):(0.1-0.3):(20-30). The calcination temperature is 500-600℃ and the time is 6-12 hours.

[0013] The molar ratio of silicon source, aluminum source, template agent, alkali metal source, and deionized water in the mixture is 1:

[0014]

[0015] The amount of seed crystal added is 1-20 wt% of the added silicon source.

[0016] The silicon source is any one or a combination of at least two of the following: silica, fine silica gel, fumed silica, silica sol, sodium silicate, or tetraethoxysilane.

[0017] The template agent is one of tetrabutylammonium hydroxide, tetrabutylammonium bromide, and 1,8-octanediamine;

[0018] The alkali metal source is one of Na or K oxides;

[0019] The aluminum source is any one or a combination of at least two of the following: aluminum isopropoxide, boehmite, sodium aluminate, aluminum hydroxide, aluminum nitrate nonahydrate, or aluminum sulfate octadecahydrate.

[0020] In step 2), the pre-crystallization reaction conditions are 12-36 h in an oven at 80-120℃; the crystallization reaction conditions are 12-72 h in an oven at 140-180℃; and the calcination conditions are 6-12 h in an oven at 500-600℃.

[0021] Step 3) involves the following steps: MEL zeolite molecular sieve and ammonium salt undergo ion exchange at 60-100℃ to obtain NH4-MEL zeolite catalyst.

[0022] Preferably, the concentration of the MEL zeolite molecular sieve is 5 g / L-20 g / L, more preferably 6-14 g / L;

[0023] The concentration of the ammonium salt is 0.1 mol / L to 5 mol / L, preferably 0.5 to 2 mol / L;

[0024] The ammonium salt is any one or a combination of at least two of the following: ammonium chloride, ammonium nitrate, ammonium acetate, and ammonium sulfate.

[0025] The present invention also includes an aluminum-rich MEL zeolite catalyst obtained by the preparation method described above.

[0026] The present invention also includes an application of the aluminum-rich MEL zeolite catalyst, which uses an alcohol with 6 or fewer carbon atoms as a reducing agent for selective catalytic reduction denitration. Preferably, the aluminum-rich MEL zeolite catalyst is applied to a denitration reaction using methanol as a reducing agent.

[0027] Compared with the prior art, the beneficial effects of the present invention are:

[0028] The technical solution of this application uses a seed-assisted method to prepare aluminum-rich MEL zeolite molecular sieves. During the synthesis process, by optimizing the preparation method and the molar ratio of raw materials, increasing pre-crystallization, and adjusting the crystallization temperature and time, the pre-crystallization stage promotes molecular sieve nucleation, ensuring that more aluminum enters the zeolite framework during the crystallization stage, thereby crystallizing to obtain zeolite with a silicon-to-aluminum ratio between 8 and 25, and further preparing MEL molecular sieves rich in acidic sites.

[0029] Compared with conventional preparation methods using other template agents, the synthesis process of this invention is simple, with a low Si / Al ratio, offering advantages in terms of economy and environmental friendliness. Furthermore, the MEL zeolite catalyst, rich in acidic sites, exhibits excellent CH3OH-SCR activity, effectively solving the problems of low activity and poor selectivity in existing selective catalytic reduction denitration catalysts using lower alcohols as reducing agents, thereby effectively implementing the catalytic purification of nitrogen oxides.

[0030] In summary, (1) the preparation method provided by this invention uses a small amount of template agent and a seed-induced method to prepare alumina-rich MEL zeolite molecular sieve, which reduces the preparation cost and has important significance in the field of practical chemical production. (2) The MEL zeolite catalyst obtained by the preparation method provided by this invention has a three-dimensional topological structure, excellent ion exchange performance, and can provide sufficient acidic sites for the CH3OH-SCR reaction. It has excellent denitrification activity and has broad application prospects in the denitrification of industrial waste gas, diesel vehicle exhaust, etc. Attached Figure Description

[0031] Figure 1 These are the XRD patterns of the products obtained in Examples 1-5 of this invention;

[0032] Figure 2These are the XRD patterns of the products obtained in Comparative Examples 1-5 of this invention;

[0033] Figure 3 These are SEM images of the MEL zeolite obtained in Examples 1-2 of this invention. Detailed Implementation

[0034] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and preferred embodiments.

[0035] Preparation of S-2 and ZSM-11 seed crystals:

[0036] S-2 seed crystals were prepared by mixing a certain amount of silica gel (40 wt%), tetrabutylammonium hydroxide solution and deionized water, stirring at room temperature for 2 h, and then transferring it to a 150 ℃ forced-air drying oven for hydrothermal treatment for 24 h to obtain white S-2 seed crystals.

[0037] The molar ratio of raw materials for S-2 seed preparation is SiO2 (silicon source): tetrabutylammonium hydroxide (template agent): H2O = 1:0.3:21. It should be noted that the molar ratio of silicon source, template agent and deionized water in S-2 seed preparation can be adjusted to 1:0.25:20 or 1:0.45:30. In this application, 1:0.3:21 is used as a preferred example for illustration.

[0038] ZSM-11 seed crystals were prepared by dissolving a certain amount of sodium aluminate and sodium hydroxide in deionized water, then adding a certain amount of tetraethyl silicate and tetrabutylammonium hydroxide, stirring for a period of time, and then transferring the mixture to a 150℃ forced-air drying oven for hydrothermal treatment for 24 hours. After filtration, drying, and calcination at 550℃ (which can be adjusted to 500℃ or 600℃) for 6 hours (which can be adjusted to 10 hours or 12 hours), ZSM-11 seed crystals were obtained.

[0039] The molar ratio of raw materials for ZSM-11 preparation is SiO2 (silicon source): 0.05Al2O3 (aluminum source): 0.3tetrabutylammonium hydroxide (template agent): 0.2Na2O (alkali metal source): 21H2O = 1:0.05:0.3:0.2:21. In this application, the molar ratio of silicon source, aluminum source, template agent, alkali metal source, and deionized water can be adjusted to 1:0.02:0.15:0.1:20 or 1:0.08:0.45:0.3:30. In this application, the molar ratio of silicon source, aluminum source, template agent, alkali metal source, and deionized water is used.

[0040] 1:0.05:0.3:0.2:21 is used as a preferred example for explanation.

[0041] Example 1

[0042] The preparation method of aluminum-rich MEL zeolite catalyst (hereinafter referred to as catalyst) includes the following steps:

[0043] 1) First, dissolve a certain amount of sodium hydroxide (alkali metal source) and sodium aluminate (aluminum source) in deionized water, then add tetrabutylammonium hydroxide (template agent) and stir for 10 minutes, then add a certain amount of silica gel (silicon source), stir thoroughly for 30 minutes to obtain a mixture, then add S-2 seed crystals, stir and age at room temperature for 4 hours, and then load into a reaction vessel.

[0044] 2) The reactor was placed in a 90℃ forced-air drying oven for pre-crystallization for 24 hours, then the temperature was increased to 170℃ for crystallization for 48 hours. The resulting product was filtered, washed, and dried, and then calcined in a muffle furnace at 550℃ for 8 hours to obtain MEL zeolite molecular sieve. The XRD pattern is shown below. Figure 1 As shown. SEM as Figure 3 As shown in (a).

[0045] The molar ratio of the raw materials for catalyst preparation is SiO2:Al2O3:tetrabutylammonium hydroxide:Na2O:

[0046] H2O = 1:0.05:0.7:0.08:21, and the mass of seed crystals added is 5% of the mass of SiO2;

[0047] 3) Weigh 1g of MEL zeolite and 5.35g of ammonium chloride and place them in 100g of deionized water. Stir at 80℃ for 8h, centrifuge and dry to obtain NH4-MEL zeolite molecular sieve. Repeat this operation 3 times. Finally, calcine at 550℃ for 4h to obtain MEL zeolite catalyst sample A.

[0048] The Si / Al ratio and CH3OH-SCR activity of the MEL zeolite catalyst are shown in Table 1.

[0049] MEL zeolite molecular sieves and ammonium salts can undergo ion exchange at 60℃, 80℃, and 100℃ to obtain NH4-MEL zeolite catalysts;

[0050] The concentration of the MEL zeolite molecular sieve can be adjusted to 5 g / L, 6 g / L, 10 g / L, 14 g / L, and 20 g / L, with the best effect observed in the range of 6-14 g / L.

[0051] The ammonium salt concentration can be 0.1 mol / L, 0.5 mol / L, 1 mol / L, 2 mol / L, 3 mol / L, or 5 mol / L, with the 0.5-2 mol / L range showing better results.

[0052] The ammonium salt is any one of ammonium chloride, ammonium nitrate, ammonium acetate, and ammonium sulfate.

[0053] Example 2

[0054] The difference between Example 1 and Example 2 is that ZSM-11 seed crystals were used instead of S-2 seed crystals to prepare MEL zeolite catalyst B. The XRD pattern is shown below. Figure 1 As shown, the Si / Al ratio and activity are shown in Table 1.

[0055] Example 3

[0056] The only difference between Example 3 and Example 2 is that the molar ratio of the raw materials for catalyst preparation is SiO2:Al2O3:1,8-octanediamine:K2O:H2O = 1:0.05:0.30:0.13:40; the MEL zeolite catalyst C was prepared, and its XRD pattern is shown below. Figure 1 As shown, the Si / Al ratio and activity are shown in Table 1.

[0057] Example 4

[0058] The only difference between Example 4 and Example 2 is that the molar ratio of the raw materials used in catalyst preparation was SiO2:Al2O3:tetrabutylammonium hydroxide:Na2O:H2O = 1:0.0625:0.70:0.08:21. MEL zeolite catalyst D was prepared, and its XRD pattern is shown below. Figure 1 As shown, the Si / Al ratio and activity are shown in Table 1;

[0059] Example 5

[0060] The only difference between Example 5 and Example 4 is that the molar ratio of the raw materials used in catalyst preparation was SiO2:Al2O3:tetrabutylammonium hydroxide:Na2O:H2O = 1:0.05:0.1:0.08:21, which prepared the MEL zeolite catalyst E. The XRD pattern is shown below. Figure 1 As shown, the Si / Al ratio and activity are shown in Table 1;

[0061] Similarly, in this application, the molar ratio of silicon source, aluminum source, template agent, alkali metal source, and deionized water can be adjusted to 1:0.04:0:0.08:20; or 1:0.08:0.8:0.2:30; the mass of added seed crystals is 1%, 10%, or 20% of the mass of SiO2; Examples 2-5 are used as preferred examples in this application for illustrative purposes.

[0062] Comparative Example 1

[0063] The only difference between Comparative Example 1 and Example 1 is that the crystallization temperature was 130℃, and MEL boiling molecular sieve F was prepared. The product was amorphous, and the XRD pattern is shown below. Figure 2 As shown, the results indicate that crystallization at a temperature of 140-180℃ for a given time yields products with good morphology.

[0064] Comparative Example 2

[0065] The only difference between Comparative Example 2 and Example 2 is that the amount of sodium aluminate added was doubled, resulting in the preparation of MEL boiling molecular sieve G, the product of which was amorphous. The XRD pattern is shown below. Figure 2 As shown.

[0066] Comparative Example 3

[0067] The only difference between Comparative Example 3 and Example 2 is the removal of the pre-crystallization stage, resulting in the preparation of MEL boiling molecular sieve H, with the product being a MEL crystal form containing impurities. The XRD pattern is shown below. Figure 2 As shown, the activities are shown in Table 1.

[0068] Comparative Example 4

[0069] The conventional MEL zeolite catalyst I was prepared to demonstrate the role of the seed-assisted method in the synthesis of alumina-rich molecular sieves. The specific steps included the following: the molar ratio of each raw material in the catalyst preparation was SiO2:Al2O3:tetrabutylammonium hydroxide:Na2O:H2O = 1:0.05:0.2:0.04:21.

[0070] First, a certain amount of sodium hydroxide and sodium aluminate were dissolved in deionized water. Then, tetrabutylammonium hydroxide was added and stirred for 10 minutes. Next, a certain amount of silica gel was added dropwise, and the mixture was stirred vigorously for 2 hours before being loaded into a reaction vessel. The reaction vessel was placed in a 170°C forced-air drying oven for crystallization reaction for 48 hours. The resulting product was filtered, washed, and dried, and then calcined in a muffle furnace at 550°C for 8 hours to obtain MEL zeolite molecular sieve. Further preparation of MEL zeolite catalyst I is described in Example 1. The XRD pattern is shown below. Figure 2 As shown.

[0071] Comparative Example 5

[0072] Dalian Zhuoran Environmental Protection Technology Co., Ltd. refractory H-type MEL molecular sieve with Si / Al ratio of 20 was calcined in air at 550℃ for 4 hours to remove potentially uncalcined template agent, thereby obtaining MEL zeolite catalyst J. XRD pattern as shown below. Figure 2 As shown, the activities are shown in Table 1.

[0073] Methods for evaluating catalyst activity

[0074] The prepared catalyst was stamped, pulverized, and sieved to obtain 20-40 mesh particles, which were then filled into a fixed-bed flow-through quartz tube. The flow rate was 300 ml / min (GHSV = 30000 h⁻¹). -1 The gas mixture was tested for activity at 150-500℃. The gas mixture consisted of: NO 500ppm; CH3OH 1000ppm; O2 10%; H2O 5%; and N2 as the balance gas. The removal activity of nitrogen oxides was calculated based on the concentrations of NOx (NO, NO2) and N2O at the outlet at different temperatures.

[0075] [NOx] conversion rate = {inlet [NOx] - outlet [NOx]} / inlet [NOx] * 100%;

[0076] [N2] Yield = {Inlet [NOx] - Outlet [NOx] - 2Outlet [N2O]} / Inlet [NOx] * 100%;

[0077] The obtained activity data are listed in Table 1.

[0078] Table 1

[0079]

[0080] The results of the above embodiments demonstrate that the raw materials for preparing MEL zeolite molecular sieves using this invention are inexpensive and the method is simple, solving the problem of the inability to synthesize low-silicon-aluminum ratio MEL in existing technologies. This invention synthesizes MEL zeolite rich in numerous acidic sites and simultaneously obtains a MEL zeolite molecular sieve catalyst with excellent CH3OH-SCR activity, solving the problems of poor low-temperature catalyst activity and narrow temperature window in existing CH3OH-SCR technologies. This has significant practical implications for environmental catalysis, especially for the treatment of sulfur-containing stationary and mobile nitrogen oxide sources.

[0081] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. Use of an aluminiferous MEL zeolite catalyst, characterized in that, The aluminum-rich MEL zeolite catalyst is applied to a selective catalytic reduction denitration reaction using an alcohol containing less than 6 carbon atoms as a reducing agent; The preparation method of the aluminum-rich MEL zeolite catalyst comprises the following steps: 1) Dissolve an alkali metal source and an aluminum source in deionized water, add a template agent and a silicon source, fully stir, then add seeds, and after aging, load into a reaction kettle; the molar ratio of the silicon source, the aluminum source, the template agent, the alkali metal source, and the deionized water is 1:(0.04-0.08):(0-0.8):(0.08-0.2):(20-30); The seeds are S-2 seeds or ZSM-11 seeds; the amount of the seeds added is 1-20% of the mass of the silicon source; 2) After a pre-crystallization reaction, perform crystallization by heating, and the obtained product is subjected to suction filtration, washing, drying, and calcination to obtain a MEL zeolite molecular sieve; the pre-crystallization reaction conditions are 80-120℃ in an oven for 12-36 h; the crystallization reaction conditions are 140-180℃ in an oven for 12-72 h; and the calcination conditions are 500-600℃ for 6-12 h; 3) The MEL zeolite molecular sieve is subjected to ion exchange to obtain an aluminum-rich MEL zeolite catalyst.

2. Use of an alumina-rich MEL zeolite catalyst according to claim 1, characterized in that, The S-2 seeds are prepared in the following manner: mix a silicon source, a template agent, and deionized water, and perform hydrothermal reaction at 140-180℃ in an oven for 12-48 h; and the obtained suspension is the S-2 seeds; The molar ratio of the silicon source, the template agent, and the deionized water is 1:0.25-0.45:20-30.

3. Use of an alumina-rich MEL zeolite catalyst according to claim 1, characterized in that, The ZSM-11 seeds are prepared in the following manner: dissolve an alkali metal source and an aluminum source in deionized water, add a template agent and a silicon source, perform hydrothermal reaction at 140-180℃ in an oven for 12-48 h, and the obtained product is subjected to suction filtration, washing, drying, and calcination to obtain ZSM-11 seeds; The molar ratio of the silicon source, the aluminum source, the template agent, the alkali metal source, and the deionized water is 1:(0.02-0.08):(0.15-0.45):(0.1-0.3):(20-30); the calcination temperature is 500-600℃, and the time is 6-12 h.

4. Use of an alumina-rich MEL zeolite catalyst according to claim 1, characterized in that, The silicon source is any one or a combination of at least two of white carbon black, fine silica gel, fumed silica, silica sol, sodium silicate, or tetraethoxysilane; The template agent is any one of tetrabutylammonium hydroxide, tetrabutylammonium bromide, and 1,8-octylenediamine; The alkali metal source is any one of Na or K oxide; The aluminum source is any one or a combination of at least two of aluminum isopropoxide, boehmite, sodium metaaluminate, aluminum hydroxide, aluminum nitrate nonahydrate, or aluminum sulfate octadecahydrate.

5. Use of an alumina-rich MEL zeolite catalyst according to claim 1, characterized in that, The specific steps of step 3) are: ion exchange of the MEL zeolite molecular sieve and an ammonium salt at 60-100℃ to obtain an NH4-MEL zeolite catalyst; The concentration of the MEL zeolite molecular sieve is 5-20 g / L; The concentration of the ammonium salt is 0.1-5 mol / L; The ammonium salt is any one or a combination of at least two of ammonium chloride, ammonium nitrate, ammonium acetate, and ammonium sulfate.

6. Use of an alumina-rich MEL zeolite catalyst according to claim 5, characterized in that, The MEL zeolite molecular sieve concentration is 6-14 g / L; The ammonium salt concentration is 0.5-2 mol / L.

7. Use of an alumina-rich MEL zeolite catalyst according to claim 1, characterized in that, The aluminum-rich MEL zeolite catalyst is applied to a denitration reaction taking methanol as a reducing agent.

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