Alcohol-SCR catalyst and preparation method and application thereof

Abstract

The invention provides an alcohol-SCR catalyst as well as a preparation method and application thereof. The alcohol-SCR catalyst comprises an aluminum-rich molecular sieve and rare earth elements loaded on the surface of the aluminum-rich molecular sieve, the aluminum-rich molecular sieve comprises an H-Beta molecular sieve and / or an H-ZSM-5 molecular sieve; the silica-alumina ratio of the H-Beta molecular sieve is 3 to 14; the silica-alumina ratio of the H-ZSM-5 molecular sieve is 5 to 30. The rare earth element is used for modifying the aluminum-rich molecular sieve, the obtained alcohol-SCR catalyst shows excellent denitration performance, the conversion efficiency of NOx is remarkably improved, and especially the conversion rate of nitric oxide is remarkably improved at the temperature of 250 DEG C or above.

Description

Technical Field

[0001] The present invention relates to the field of catalytic technology, and relates to a catalyst for removing nitrogen oxides, and particularly relates to an alcohol-SCR catalyst and its preparation method and application. Background Art

[0002] With the increasing global attention to environmental protection, the emission restrictions on pollutants such as nitrogen oxides in various countries are becoming more and more stringent. The alcohol-SCR catalyst provides a new technical approach to meet the strict environmental protection requirements. The working principle of the alcohol-SCR catalyst is to use alcohols as reducing agents to selectively catalytically reduce nitrogen oxides to generate N2 and O2. As long as the alcohols as reducing agents are compounds with reducing ability at the temperature of the reduction treatment of the waste gas. The scenarios of using alcohols as reducing agents to remove NOx are very extensive, including the tail gas treatment of automobiles, ships, non-road mobile sources or stationary sources, etc.

[0003] JP2013226544A discloses a method for denitrifying industrial waste gas using a catalyst with cobalt supported on a Na-type molecular sieve. The Na-type molecular sieve is preferably a ZSM-5 (MFI) or MOR-type molecular sieve. However, the denitrification efficiency of this catalyst is poor.

[0004] WO2013146729A1 discloses a method for denitrifying industrial waste gas using a catalyst with cobalt supported on a Na-type molecular sieve modified by an alkali metal or an alkaline earth metal. However, the preparation method of the catalyst disclosed in this invention is complex, and there is still great room for improvement in the denitrification performance, which cannot meet the actual application requirements.

[0005] CN114206495A discloses a method for applying a FER molecular sieve catalyst to denitrification using alcohols as reducing agents. The hydrothermal synthesis method of the catalyst disclosed in this method is complex, the production cost is high, and it is not easy to industrialize and promote the catalyst.

[0006] Therefore, it is of great significance to develop an alcohol-SCR catalyst with simple composition, low preparation cost, excellent catalytic performance, and suitable for efficient and sustainable denitrification technology. Summary of the Invention

[0007] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide an alcohol-SCR catalyst and its preparation method and application. The present invention selects an aluminum-rich molecular sieve as the matrix of the alcohol-SCR catalyst and modifies it with rare earth elements. The obtained alcohol-SCR catalyst exhibits excellent denitrification performance, especially above 250 °C, and the nitrogen oxide conversion rate is significantly improved.

[0008] To achieve the purpose of this invention, the following technical solutions are adopted by the present invention:

[0009] In a first aspect, the present invention provides an alcohol-SCR catalyst, which comprises an aluminum-rich molecular sieve and rare earth elements supported on the surface of the aluminum-rich molecular sieve;

[0010] The aluminum-rich molecular sieve comprises H-Beta molecular sieve and / or H-ZSM-5 molecular sieve;

[0011] The H-Beta molecular sieve has a silica-alumina ratio of 3 - 14;

[0012] The H-ZSM-5 molecular sieve has a silica-alumina ratio of 5 - 30.

[0013] By identifying the type and silica-alumina ratio of the aluminum-rich molecular sieve, the present invention selects H-Beta molecular sieve with a silica-alumina ratio of 3 - 14 and / or H-ZSM-5 molecular sieve with a silica-alumina ratio of 5 - 30 as the matrix of the alcohol-SCR catalyst. The aluminum-rich molecular sieve has abundant Al sites, and the Si-O(H)-Al sites and adjacent extra-framework aluminum (EFAl) species can synergistically catalyze the conversion of nitrogen oxides into N2; modifying it with rare earth elements promotes the activation of CH3OH and NO, optimizes the reaction path, and the obtained alcohol-SCR catalyst exhibits excellent denitrification performance, especially above 250 °C, and the conversion rate of nitrogen oxides is significantly improved.

[0014] Preferably, the specific surface area of the aluminum-rich molecular sieve is 300 m 2 / g - 800 m 2 / g.

[0015] Preferably, the rare earth elements include any one or a combination of at least two of lanthanum, cerium, praseodymium, neodymium, samarium, gadolinium, erbium, ytterbium or yttrium, and are preferably lanthanum and / or samarium.

[0016] Preferably, the mass ratio of the rare earth elements to the aluminum-rich molecular sieve is (0.5 - 20):100.

[0017] In a second aspect, the present invention provides a preparation method of the alcohol-SCR catalyst as described in the first aspect, and the preparation method includes:

[0018] Mixing the aluminum-rich molecular sieve and a rare earth compound to prepare a precursor of the alcohol-SCR catalyst; calcining the precursor of the alcohol-SCR catalyst to obtain the alcohol-SCR catalyst.

[0019] Preferably, the rare earth compound includes any one or a combination of at least two of oxides, nitrates, acetates or chlorides of the rare earth elements.

[0020] Preferably, the method for preparing the alcohol-SCR catalyst precursor includes any one of liquid-phase mixing impregnation method, equal-volume impregnation method, liquid-phase ion exchange method or solid-state grinding method, and preferably the liquid-phase mixing impregnation method.

[0021] Preferably, the liquid-phase mixing impregnation method includes:

[0022] Impregnate the aluminum-rich molecular sieve in an aqueous solution of a rare earth compound, stir in a water bath, then perform rotary evaporation and drying to obtain the alcohol-SCR catalyst precursor.

[0023] Preferably, the solid-liquid ratio of the aluminum-rich molecular sieve to the aqueous solution of the rare earth compound is 0.001 g / mL - 0.5 g / mL, and preferably 0.01 g / mL - 0.1 g / mL.

[0024] Preferably, the temperature of the water bath stirring is 25°C - 80°C, and the time of the water bath stirring is 0.5 h - 8 h.

[0025] Preferably, the temperature of the rotary evaporation is 25°C - 80°C.

[0026] Preferably, the temperature of the drying is 60°C - 100°C.

[0027] Preferably, the temperature of the calcination is 300°C - 800°C, and preferably 400°C - 600°C.

[0028] Preferably, the time of the calcination is 1 h - 10 h, and preferably 3 h - 6 h.

[0029] In a third aspect, the present invention provides an application of the alcohol-SCR catalyst as described in the first aspect, and the alcohol-SCR catalyst is applied to the field of nitrogen oxide removal.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] (1) By identifying the type and silicon-aluminum ratio of the aluminum-rich molecular sieve, the present invention selects H-Beta molecular sieve with a silicon-aluminum ratio of 3 - 14 and / or H-ZSM-5 molecular sieve with a silicon-aluminum ratio of 5 - 30 as the matrix, and a specific aluminum-rich molecular sieve as the matrix of the alcohol-SCR catalyst, and modifies it with rare earth elements, so that the alcohol-SCR catalyst has a simple composition and exhibits excellent denitration performance. Especially above 250°C, the conversion rate of nitrogen oxides is significantly improved.

[0032] (2) The preparation method of the alcohol-SCR catalyst provided by the present invention is simple and easy to implement, has a low preparation cost, and is easy to realize industrial application. Description of the Drawings

[0033] Figure 1It is the activity test results of the alcohol-SCR catalysts provided by Example 1, Example 2 and Comparative Example 3 at different temperatures. Detailed implementation manners

[0034] The technical solutions of the present invention will be further described below through specific implementation manners. Those skilled in the art should understand that the described embodiments are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the term "including" and any variations thereof in this application are intended to cover non-exclusive inclusion.

[0036] The purpose of the present invention is to provide an alcohol-SCR catalyst, a preparation method thereof and an application thereof.

[0037] In a specific implementation manner, the present invention provides an alcohol-SCR catalyst, and the alcohol-SCR catalyst includes an aluminosilicate zeolite and rare earth elements supported on the surface of the aluminosilicate zeolite;

[0038] The aluminosilicate zeolite includes H-Beta zeolite and / or H-ZSM-5 zeolite.

[0039] The silicon-aluminum ratio of the H-Beta zeolite is 3-14;

[0040] The silicon-aluminum ratio of the H-ZSM-5 zeolite is 5-30.

[0041] In the present invention, the silicon-aluminum ratio of the aluminosilicate zeolite refers to the molar ratio of Si atoms to Al atoms. The silicon-aluminum ratio of the H-Beta zeolite is 3-14, for example, it can be 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 or 14, including but not limited to the listed values, and other unlisted values within the numerical range are equally applicable; the silicon-aluminum ratio of the H-ZSM-5 zeolite is 5-30, for example, it can be 5, 10, 15, 20, 25 or 30, including but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0042] By identifying the types and silica-alumina ratios of aluminosilicate zeolites, H-Beta zeolites with a silica-alumina ratio of 3 - 14 and / or H-ZSM-5 zeolites with a silica-alumina ratio of 5 - 30 are selected as the matrix of the alcohol-SCR catalyst. Aluminosilicate zeolites have abundant Al sites, and the synergistic catalysis of Si-O(H)-Al sites and adjacent extra-framework aluminum (EFAl) species can catalyze the conversion of nitrogen oxides into N2; modification with rare earth elements promotes the activation of CH3OH and NO, optimizes the reaction path, and the resulting alcohol-SCR catalyst exhibits excellent denitrification performance, especially above 250 °C, with a significant increase in the conversion rate of nitrogen oxides.

[0043] In some embodiments, the specific surface area of the aluminosilicate zeolite is 300 m 2 / g - 800 m 2 / g, for example, it can be 300 m 2 / g, 350 m 2 / g, 400 m 2 / g, 450 m 2 / g, 500 m 2 / g, 550 m 2 / g, 600 m 2 / g, 650 m 2 / g, 700 m 2 / g, 750 m 2 / g or 800 m 2 / g, including but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0044] In some embodiments, the rare earth element includes any one or a combination of at least two of lanthanum, cerium, praseodymium, neodymium, samarium, gadolinium, erbium, ytterbium, or yttrium. Typical but non-limiting combinations include the combination of lanthanum and cerium, the combination of praseodymium and neodymium, the combination of samarium and gadolinium, or the combination of erbium and yttrium. Preferably, it is lanthanum and / or samarium.

[0045] In some embodiments, the mass ratio of the rare earth element to the aluminosilicate zeolite is (0.5 - 20):100. For example, it can be 0.5:100, 1:100, 2:100, 3:100, 4:100, 6:100, 8:100, 10:100, 12:100, 14:100, 16:100, 18:100, or 20:100, including but not limited to the listed values, and other unlisted values within the numerical range are equally applicable. Preferably, it is (1 - 4):100.

[0046] In another specific embodiment, the present invention provides a preparation method of the alcohol-SCR catalyst as described in the above specific embodiment, and the preparation method includes:

[0047] Mix the aluminum-rich molecular sieve with a rare earth compound to prepare a precursor of the alcohol-SCR catalyst; calcine the precursor of the alcohol-SCR catalyst to obtain the alcohol-SCR catalyst.

[0048] In some embodiments, the rare earth compound includes any one or a combination of at least two of oxides, nitrates, acetates, or chlorides of the rare earth element. Typical but non-limiting combinations include combinations of oxides and nitrates of rare earth elements, combinations of acetates and chlorides, combinations of nitrates and acetates, or combinations of chlorides and oxides.

[0049] In some embodiments, the method for preparing the precursor of the alcohol-SCR catalyst includes any one of liquid-phase mixing impregnation method, equal-volume impregnation method, liquid-phase ion exchange method, or solid-state grinding method, preferably the liquid-phase mixing impregnation method.

[0050] In some embodiments, the liquid-phase mixing impregnation method includes:

[0051] Immerse the aluminum-rich molecular sieve in an aqueous solution of the rare earth compound, stir in a water bath, then perform rotary evaporation and drying to obtain the precursor of the alcohol-SCR catalyst.

[0052] In some embodiments, the equal-volume impregnation method includes:

[0053] Drop the solution of the rare earth compound into the aluminum-rich support, stir evenly, and dry to obtain the precursor of the alcohol-SCR catalyst.

[0054] In some embodiments, the liquid-phase ion exchange method includes:

[0055] Immerse the aluminum-rich molecular sieve in an aqueous solution of the rare earth compound, stir in a water bath, then filter and rinse with deionized water, and dry to obtain the precursor of the alcohol-SCR catalyst.

[0056] In some embodiments, the solid-state grinding method includes:

[0057] Perform solid-state grinding and mixing of the aluminum-rich molecular sieve and the rare earth compound to obtain the precursor of the alcohol-SCR catalyst.

[0058] In some embodiments, in the liquid-phase mixing impregnation method and / or the liquid-phase ion exchange method, the solid-liquid ratio of the dealuminated zeolite to the aqueous solution of the rare earth compound is independently 0.001 g / mL - 0.5 g / mL. For example, it can be 0.001 g / mL, 0.005 g / mL, 0.01 g / mL, 0.02 g / mL, 0.03 g / mL, 0.04 g / mL, 0.05 g / mL, 0.06 g / mL, 0.07 g / mL, 0.08 g / mL, 0.09 g / mL, 0.1 g / mL, 0.2 g / mL, 0.4 g / mL or 0.5 g / mL. This includes but is not limited to the listed values, and other unlisted values within the numerical range are equally applicable. Preferably, it is 0.01 g / mL - 0.1 g / mL.

[0059] In some embodiments, in the liquid-phase mixing impregnation method and / or the liquid-phase ion exchange method, the temperature of the water bath stirring is independently 25°C - 80°C. For example, it can be 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C or 80°C. This includes but is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0060] In some embodiments, the time of the water bath stirring is 0.5 h - 8 h. For example, it can be 0.5 h, 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h or 8 h. This includes but is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0061] In some embodiments, the temperature of the rotary evaporation is 25°C - 80°C. For example, it can be 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C or 80°C. This includes but is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0062] In some embodiments, in the liquid-phase mixing impregnation method, the equal-volume impregnation method or the liquid-phase ion exchange method, the drying temperature is independently 60°C - 100°C. For example, it can be 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C or 100°C. This includes but is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0063] In the present invention, the time for drying the alcohol-SCR catalyst precursor is not particularly limited, with the aim of completely volatilizing the residual solvent.

[0064] In some embodiments, the calcination temperature is 300°C - 800°C. For example, it can be 300°C, 350°C, 400°C, 450°C, 500°C, 550°C, 600°C, 650°C, 700°C, 750°C or 800°C, including but not limited to the listed values. Other unlisted values within the numerical range are equally applicable. Preferably, it is 400°C - 600°C.

[0065] In some embodiments, the calcination time is 1h - 10h. For example, it can be 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h or 10h, including but not limited to the listed values. Other unlisted values within the numerical range are equally applicable. Preferably, it is 3h - 6h.

[0066] In another specific embodiment, the present invention is the application of the alcohol-SCR catalyst as described in the above specific embodiment, and the alcohol-SCR catalyst is applied to the field of nitrogen oxide removal.

[0067] When the alcohol-SCR catalyst is applied to nitrogen oxide removal, the alcohol used as the reducing agent can be any compound that has a reducing ability at the temperature of the reduction treatment of the waste gas, without special limitation. Preferably, an alcohol with 6 or fewer carbon atoms is used, such as methanol, ethanol, propanol, isopropanol, etc. More preferably, it is methanol or ethanol. The alcohol-SCR catalyst is applied to the scenario of removing NOx using alcohol as the reducing agent, including but not limited to the tail gas treatment of automobiles, ships, non-road mobile sources or stationary sources.

[0068] Example 1

[0069] This example provides an alcohol-SCR catalyst, which includes an H-Beta molecular sieve with a specific surface area of 500 m 2 / g and a Si / Al ratio of 5, and samarium element loaded on the surface of the H-Beta molecular sieve. Among them, the mass ratio of the samarium element to the H-Beta molecular sieve is 2:100.

[0070] The preparation method of the alcohol-SCR catalyst includes:

[0071] According to the mass ratio of the samarium element to the H-Beta molecular sieve of 2:100 and a solid solution ratio of 0.01 g / mL, the H-Beta molecular sieve with a Si / Al ratio of 5 is impregnated in an aqueous solution of Sm(NO3)3·6H2O, stirred in a water bath at 40°C for 5h, rotary evaporated at 60°C, and then dried at 100°C to obtain the precursor of the alcohol-SCR catalyst; at 550°C, the precursor of the alcohol-SCR catalyst is calcined for 4h to prepare the alcohol-SCR catalyst.

[0072] Example 2

[0073] This example provides an alcohol-SCR catalyst. Except that the samarium element is replaced with an equal mass of lanthanum element and the H-Beta zeolite with Si / Al of 5 is replaced with the H-Beta zeolite with Si / Al of 14, the rest are the same as in Example 1.

[0074] The preparation method of the alcohol-SCR catalyst is the same as that in Example 1, except that Sm(NO3)3·6H2O is replaced with La(NO3)3·6H2O according to the equal mass of samarium element and lanthanum element, and the H-Beta zeolite with Si / Al of 5 is replaced with the H-Beta zeolite with Si / Al of 14.

[0075] Example 3

[0076] This example provides an alcohol-SCR catalyst. The alcohol-SCR catalyst includes an H-Beta zeolite with a specific surface area of 800 m 2 / g and Si / Al of 8, as well as samarium element and lanthanum element supported on the surface of the H-Beta zeolite. Among them, the mass ratio of the total mass of samarium element and lanthanum element to the mass of the H-Beta zeolite is 4:100.

[0077] The preparation method of the alcohol-SCR catalyst includes:

[0078] The mass ratio of the total mass of samarium element and lanthanum element to the mass of the H-Beta zeolite is 4:100, and the solid solution ratio is 0.08 g / mL. The H-Beta zeolite with Si / Al of 8 is impregnated in an aqueous solution of Sm(NO3)3·6H2O and La(NO3)3·6H2O, stirred in a water bath at 25°C for 8 h, rotary evaporated at 25°C, and then dried at 60°C to obtain the precursor of the alcohol-SCR catalyst; the precursor of the alcohol-SCR catalyst is calcined at 400°C for 6 h to prepare the alcohol-SCR catalyst.

[0079] Example 4

[0080] This example provides an alcohol-SCR catalyst. The alcohol-SCR catalyst includes an H-ZSM-5 zeolite with a specific surface area of 300 m 2 / g and Si / Al of 14, as well as praseodymium element supported on the surface of the H-ZSM-5 zeolite. Among them, the mass ratio of praseodymium element to the mass of the H-ZSM-5 zeolite is 1:100.

[0081] The preparation method of the alcohol-SCR catalyst includes:

[0082] According to the mass ratio of praseodymium element to H-ZSM-5 molecular sieve being 1:100, the H-ZSM-5 molecular sieve with Si / Al of 14 and Pr(NO3)3·6H2O were subjected to solid-state grinding to obtain the precursor of the alcohol-SCR catalyst; at 600 °C, the precursor of the alcohol-SCR catalyst was calcined for 3 h to prepare the alcohol-SCR catalyst.

[0083] Example 5

[0084] This example provides an alcohol-SCR catalyst, which includes an H-ZSM-5 molecular sieve with a specific surface area of 450 m 2 / g and Si / Al of 5, and ytterbium element loaded on the surface of the H-ZSM-5 molecular sieve. Among them, the mass ratio of ytterbium element to H-ZSM-5 molecular sieve is 12:100.

[0085] The preparation method of the alcohol-SCR catalyst includes:

[0086] According to the mass ratio of ytterbium element to H-ZSM-5 molecular sieve being 12:100, the H-ZSM-5 molecular sieve with Si / Al of 5 and Yb(NO3)3·5H2O were subjected to solid-state grinding to obtain the precursor of the alcohol-SCR catalyst; at 450 °C, the precursor of the alcohol-SCR catalyst was calcined for 6 h to prepare the alcohol-SCR catalyst.

[0087] Example 6

[0088] This example provides an alcohol-SCR catalyst, which includes an H-ZSM-5 molecular sieve with a specific surface area of 600 m 2 / g and Si / Al of 30, and yttrium element loaded on the surface of the H-ZSM-5 molecular sieve. Among them, the mass ratio of yttrium element to H-ZSM-5 molecular sieve is 16:100.

[0089] The preparation method of the alcohol-SCR catalyst includes:

[0090] According to the mass ratio of yttrium element to H-ZSM-5 molecular sieve being 16:100 and the solid solution ratio being 0.2 g / mL, the H-ZSM-5 molecular sieve with Si / Al of 30 was impregnated in an aqueous solution of Y(NO3)3·6H2O, stirred in a water bath at 25 °C for 8 h, rotary evaporated at 25 °C, and dried at 60 °C to obtain the precursor of the alcohol-SCR catalyst; at 500 °C, the precursor of the alcohol-SCR catalyst was calcined for 4 h to prepare the alcohol-SCR catalyst.

[0091] Example 7

[0092] This example provides an alcohol-SCR catalyst. Except that the mass ratio of samarium element to H-Beta zeolite is 0.5:100, the rest are the same as in Example 1.

[0093] The preparation method of the alcohol-SCR catalyst is the same as that in Example 1, except that the H-Beta zeolite with Si / Al of 5 is impregnated in an aqueous solution of Sm(NO3)3·6H2O according to the mass ratio of samarium element to H-Beta zeolite of 0.5:100 and a solid solution ratio of 0.001 g / mL.

[0094] Example 8

[0095] This example provides an alcohol-SCR catalyst. Except that the mass ratio of samarium element to H-Beta zeolite is 20:100, the rest are the same as in Example 1.

[0096] The preparation method of the alcohol-SCR catalyst is the same as that in Example 1, except that the H-Beta zeolite with Si / Al of 5 is impregnated in an aqueous solution of Sm(NO3)3·6H2O according to the mass ratio of samarium element to H-Beta zeolite of 20:100 and a solid solution ratio of 0.2 g / mL.

[0097] Example 9

[0098] This example provides an alcohol-SCR catalyst. The difference between this alcohol-SCR catalyst and that in Example 1 is that during the preparation process, the temperature for calcining the alcohol-SCR catalyst precursor is 300 °C, and the rest are the same as in Example 1.

[0099] Example 10

[0100] This example provides an alcohol-SCR catalyst. The difference between this alcohol-SCR catalyst and that in Example 1 is that during the preparation process, the temperature for calcining the alcohol-SCR catalyst precursor is 800 °C, and the rest are the same as in Example 1.

[0101] Comparative Example 1

[0102] This comparative example provides an alcohol-SCR catalyst. Except that the Si / Al of the H-Beta zeolite is 20, the rest are the same as in Example 1.

[0103] The preparation method of the alcohol-SCR catalyst is the same as that in Example 1, except that the H-Beta zeolite with Si / Al of 20 is impregnated in an aqueous solution of Sm(NO3)3·6H2O.

[0104] Comparative Example 2

[0105] This comparative example provides an alcohol-SCR catalyst. Except that the Si / Al of the H-ZSM-5 molecular sieve is 40, the rest are the same as in Example 4.

[0106] The preparation method of the alcohol-SCR catalyst is the same as that in Example 4, except that the H-ZSM-5 molecular sieve with Si / Al of 40 is subjected to solid-state grinding with Pr(NO3)3·6H2O.

[0107] Comparative Example 3

[0108] This comparative example provides an alcohol-SCR catalyst, and the alcohol-SCR catalyst is an H-Beta molecular sieve with a specific surface area of 500 m 2 / g and Si / Al of 5.

[0109] Performance test:

[0110] The present invention tests the activities of the alcohol-SCR catalysts provided in all the above examples and comparative examples at different temperatures, detects the component composition in the tail gas by a Fourier transform infrared spectrometer, and calculates the conversion efficiency of NO x Among them, the reaction space velocity is 30,000 h -1 , and the test gas composition is: [NO]=1000 ppm, [CH3OH]=2000 ppm, [O2]=10%, [H2O]=5%, and the balance gas is N2. The test results are shown in Table 1.

[0111] Figure 1 are the activity test results of the alcohol-SCR catalysts provided in Example 1, Example 2 and Comparative Example 3 at different temperatures.

[0112] Table 1

[0113]

[0114]

[0115] According to the data results of Example 1 and Comparative Examples 1-2, if the silicon-aluminum ratio of the aluminum-rich molecular sieve used is not within the range defined in the present invention, the performance of the alcohol-SCR catalyst will decrease significantly.

[0116] According to the data results of Example 1 to Example 3 and Example 7 to Example 10 and Comparative Example 3, after using rare earth elements to modify the aluminum-rich molecular sieve, the obtained alcohol-SCR catalyst exhibits excellent denitrification performance, and the conversion efficiency of NO x is significantly improved.

[0117] The applicant declares that the above description is only a specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the protection scope and the disclosure scope of the present invention.

Claims

1. An alcohol-SCR catalyst, characterized in that, The alcohol-SCR catalyst includes an aluminum-rich molecular sieve and rare earth elements supported on the surface of the aluminum-rich molecular sieve; The aluminum-rich molecular sieve includes H-Beta molecular sieve and / or H-ZSM-5 molecular sieve; The silicon-aluminum ratio of the H-Beta molecular sieve is 3-14; The silicon-aluminum ratio of the H-ZSM-5 molecular sieve is 5-30.

2. The alcohol-SCR catalyst according to claim 1, characterized in that, The specific surface area of the aluminosilicate zeolite is 300 m 2 / g - 800 m 2 / g.

3. The alcohol-SCR catalyst according to claim 1 or 2, characterized in that, The rare earth elements include any one or a combination of at least two of lanthanum, cerium, praseodymium, neodymium, samarium, gadolinium, erbium, ytterbium or yttrium; And / or, the mass ratio of the rare earth elements to the aluminum-rich molecular sieve is (0.5-20):

100.

4. A method for preparing an alcohol-SCR catalyst according to any one of claims 1-3, characterized in that, The preparation method includes: Mixing the aluminum-rich molecular sieve and a rare earth compound to prepare a precursor of the alcohol-SCR catalyst; calcining the precursor of the alcohol-SCR catalyst to obtain the alcohol-SCR catalyst.

5. The preparation method according to claim 4, characterized in that, The rare earth compound includes any one or a combination of at least two of oxides, nitrates, acetates or chlorides of the rare earth elements.

6. The preparation method according to claim 4 or 5, characterized in that, The method for preparing the precursor of the alcohol-SCR catalyst includes any one of liquid-phase mixing impregnation method, equal-volume impregnation method, liquid-phase ion exchange method or solid-state grinding method, preferably the liquid-phase mixing impregnation method.

7. The preparation method according to claim 6, characterized in that, The liquid-phase mixing impregnation method includes: Impregnating the aluminum-rich molecular sieve in an aqueous solution of a rare earth compound, stirring in a water bath, then rotary evaporating and drying to obtain the precursor of the alcohol-SCR catalyst; And / or, the solid-liquid ratio of the aluminum-rich molecular sieve to the aqueous solution of the rare earth compound is 0.001g / mL - 0.5g / mL; And / or, the temperature of the water bath stirring is 25°C - 80°C; And / or, the time of the water bath stirring is 0.5h - 8h; And / or, the temperature of the rotary evaporation is 25°C - 80°C; And / or, the temperature of the drying is 60°C - 100°C.

8. The preparation method according to claim 7, characterized in that, The solid-liquid ratio of the aluminum-rich molecular sieve to the aqueous solution of the rare earth compound is 0.01g / mL - 0.1g / mL.

9. The preparation method according to claim 4, characterized in that, The temperature of the calcination is 300°C - 800°C; And / or, the time of the calcination is 1h - 10h.

10. Use of the alcohol-SCR catalyst according to any one of claims 1-3, characterized in that, The alcohol-SCR catalyst is applied to the field of nitrogen oxide removal.

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