Vanadium-containing FER type zeolite and application thereof

Abstract

The vanadium-containing FER type zeolite at least comprises silicon, aluminum and oxygen as framework atoms, and the molar ratio of silicon atoms to aluminum atoms is (2-30): 1; based on the mass of the zeolite, the mass percentage content of vanadium is 0.1-3%; when the zeolite is analyzed by adopting a 29Si solid nuclear magnetic resonance spectrum, the peak area in a chemical shift interval of-110 to-90 ppm accounts for 23% or more and 85% or less of the peak area in a chemical shift interval of-125 to-90 ppm. The invention further provides a preparation method of the vanadium-containing FER type zeolite and application of the vanadium-containing FER type zeolite as a catalyst in selective catalytic reduction denitration with alcohol as a reducing agent.

Description

Technical Field

[0001] The present disclosure relates to the field of denitration catalysts, and more specifically, to a vanadium-containing FER-type zeolite denitration catalyst, a preparation method thereof, and an application thereof. Background Art

[0002] Nitrogen oxides (NO x ) have strong irritation and corrosiveness and can cause damage to human health. In addition, nitrogen oxides in the atmosphere are also prone to interact with other harmful compounds to generate harmful substances such as sulfates and nitrates, which are one of the main culprits of atmospheric haze. Selective catalytic reduction technology (SCR) is currently the main flue gas denitration technology. It uses a reducing agent to selectively react with nitrogen oxides in the flue gas under the action of a catalyst to generate nitrogen and water, thereby removing nitrogen oxides. However, when treating industrial waste gas generated from high-sulfur fuels such as coal and heavy oil, a certain amount of sulfur oxide will be generated during the industrial process of such fuels. When using ammonia as a reducing agent in the flue gas denitration process, sulfur oxide often reacts with the reducing agent ammonia to form ammonium sulfate by-products. Since ammonium sulfate is corrosive and sticky, it is easy to adhere to the surface of objects, which will lead to problems such as catalyst deactivation and equipment failure.

[0003] Using lower alcohol compounds as reducing agents, they will not react with sulfur oxide to form deposits, and liquid lower alcohols as reducing agents (alcohol-SCR) are easier to store safely than ammonia water, and will not cause problems such as pipeline blockage easily caused by urea precipitation at low temperatures similar to urea aqueous solution. For example, JP2022161381A discloses using MFI or FER-type zeolite loaded with Ag and Bi as active metals for denitration with methanol as a reducing agent. Although this catalyst can achieve good catalytic activity at 300 °C, carbon deposition is likely to occur during the reaction process, resulting in a decrease in catalytic activity, and this published literature believes that vanadium is not suitable as a metal active component for the reaction of denitration with methanol as a reducing agent.

[0004] However, the supported denitration catalysts using lower alcohols as reducing agents in this field generally have problems such as high reaction temperature, for example, a catalytic reaction temperature above 300 °C, or low denitration efficiency, unstable structure, or deactivation or activity reduction due to organic coking or carbon deposition during use. Summary of the Invention

[0005] The inventors of the present disclosure have conducted in-depth research on the technical problems existing in this field and found that the above one or more technical problems can be solved through the following technical solutions.

[0006] According to a first aspect of the present disclosure, there is provided a vanadium-containing FER-type zeolite, the zeolite comprising at least silicon, aluminum, and oxygen as framework atoms, wherein the molar ratio of silicon atoms to aluminum atoms is 2 to 30:1, and wherein, based on the mass of the zeolite, the mass percentage of vanadium is 0.1 to 3%, and when the zeolite is analyzed by 29 Si solid nuclear magnetic resonance spectroscopy, the peak area in the chemical shift range of -110 to -90 ppm accounts for more than 23% and less than 85% of the peak area in the chemical shift range of -125 to -90 ppm.

[0007] In some embodiments, when the zeolite is analyzed by 27 Al solid nuclear magnetic resonance spectroscopy, the peak area in the chemical shift range of -50 to 40 ppm accounts for 60% or less of the peak area in the chemical shift range of -50 to 150 ppm.

[0008] In some embodiments, vanadium is in the framework of the zeolite and / or outside the framework of the zeolite, for example, outside the framework of the zeolite.

[0009] In some embodiments, cations are present outside the framework of the zeolite, and the cations include hydrogen ions or ammonium ions.

[0010] According to a second aspect of the present disclosure, there is provided a method for preparing a vanadium-containing FER-type zeolite, the method comprising: removing alkali metal ions in a zeolite raw material by an ion exchange method to obtain a treated zeolite, and then loading vanadium onto the treated zeolite to obtain the vanadium-containing FER-type zeolite; or loading vanadium onto an H-type or ammonium-type FER-type zeolite to obtain the vanadium-containing FER-type zeolite.

[0011] In some embodiments, the vanadium is provided by a vanadium source selected from ammonium metavanadate, sodium metavanadate, potassium metavanadate, sodium orthovanadate, vanadyl sulfate, oxalyl vanadate, vanadium tetrachloride, vanadium oxychloride, or any combination thereof. Preferably, the vanadium source is in solution form, and more preferably, the vanadium source is in aqueous solution form;

[0012] Optionally, the mass ratio of the vanadium source (calculated as vanadium metal): H-type or ammonium-type FER-type zeolite is 0.0005 - 0.05 g V: 1 g of H-type FER-type zeolite.

[0013] According to a third aspect of the present disclosure, there is provided a catalytic reactor for nitrogen oxide purification, the catalytic reactor comprising the vanadium-containing FER-type zeolite described in the first aspect or the vanadium-containing FER-type zeolite prepared by the method described in the second aspect as a denitrification catalyst.

[0014] According to a fourth aspect of the present disclosure, there is provided a nitrogen oxide purification system, and the system is provided with the catalytic reactor for nitrogen oxide purification described in the third aspect

[0015] According to a fifth aspect of the present disclosure, a denitration method is provided. The method includes using the vanadium-containing FER-type zeolite described in the first aspect or the vanadium-containing FER-type zeolite prepared by the method described in the second aspect as a denitration catalyst, and using an alcohol having 6 or less carbon atoms as a reducing agent for selective catalytic reduction denitration.

[0016] According to a sixth aspect of the present disclosure, a method for improving the low-temperature denitration performance and / or durability of a FER-type zeolite is provided. The method includes loading vanadium on the FER-type zeolite.

[0017] The present disclosure at least solves the problems such as low reaction activity of the catalyst in the temperature range below 300 °C and insufficient high-temperature hydrothermal stability when using lower alcohols such as methanol as a reducing agent for selective catalytic reduction denitration. The present disclosure provides a lower alcohol-SCR denitration catalyst having high catalytic activity and high hydrothermal stability in the temperature range below 300 °C, thereby solving the problem of denitration treatment of industrial flue gas with a relatively low emission temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The embodiments illustrated herein are further described below with reference to the accompanying drawings. However, the accompanying drawings are only for enabling those skilled in the art to better understand the present invention and are not intended to limit the scope of the present invention.

[0019] Figure 1 is the XRD pattern of zeolite A prepared according to an embodiment of the present disclosure;

[0020] Figure 2 is of zeolite A prepared according to an embodiment of the present disclosure 29 Si solid nuclear magnetic resonance spectrum;

[0021] Figure 3 is of zeolite A prepared according to an embodiment of the present disclosure 29 Al solid nuclear magnetic resonance spectrum;

[0022] Figure 4 is the XRD pattern of zeolite B prepared according to an embodiment of the present disclosure;

[0023] Figure 5 is of zeolite B prepared according to an embodiment of the present disclosure 29 Si solid nuclear magnetic resonance spectrum;

[0024] Figure 6 is of zeolite B prepared according to an embodiment of the present disclosure 27 Al solid nuclear magnetic resonance spectrum;

[0025] Figure 7XRD pattern of Zeolite C prepared according to an embodiment of the present disclosure;

[0026] Figure 8 is the 29 Si solid nuclear magnetic resonance spectrum of Zeolite C prepared according to an embodiment of the present disclosure;

[0027] Figure 9 is the 27 Al solid nuclear magnetic resonance spectrum of Zeolite C prepared according to an embodiment of the present disclosure;

[0028] Figure 10 XRD pattern of Zeolite D prepared according to an embodiment of the present disclosure;

[0029] Figure 11 is the 29 Si solid nuclear magnetic resonance spectrum of Zeolite D prepared according to an embodiment of the present disclosure;

[0030] Figure 12 is the 27 Al solid nuclear magnetic resonance spectrum of Zeolite D prepared according to an embodiment of the present disclosure;

[0031] Figure 13 XRD pattern of Zeolite E prepared according to an embodiment of the present disclosure;

[0032] Figure 14 is the 29 Si solid nuclear magnetic resonance spectrum of Zeolite E prepared according to an embodiment of the present disclosure;

[0033] Figure 15 is the 27 Al solid nuclear magnetic resonance spectrum of Zeolite E prepared according to an embodiment of the present disclosure;

[0034] Figure 16 XRD pattern of Zeolite F prepared according to an embodiment of the present disclosure;

[0035] Figure 17 is the 29 Si solid nuclear magnetic resonance spectrum of Zeolite F prepared according to an embodiment of the present disclosure;

[0036] Figure 18 is the 27 Al solid nuclear magnetic resonance spectrum of Zeolite F prepared according to an embodiment of the present disclosure;

[0037] Figure 19 XRD pattern of Zeolite G prepared according to an embodiment of the present disclosure;

[0038] Figure 20prepared according to an embodiment of the present disclosure of zeolite G 29 Si solid nuclear magnetic resonance spectrum;

[0039] Figure 21 prepared according to an embodiment of the present disclosure of zeolite G 27 Al solid nuclear magnetic resonance spectrum;

[0040] Figure 22 XRD pattern of zeolite H prepared according to an embodiment of the present disclosure;

[0041] Figure 23 prepared according to an embodiment of the present disclosure of zeolite H 29 Si solid nuclear magnetic resonance spectrum;

[0042] Figure 24 prepared according to an embodiment of the present disclosure of zeolite H 27 Al solid nuclear magnetic resonance spectrum;

[0043] Figure 25 XRD pattern of zeolite I prepared according to an embodiment of the present disclosure;

[0044] Figure 26 prepared according to an embodiment of the present disclosure of zeolite I 29 Si solid nuclear magnetic resonance spectrum;

[0045] Figure 27 prepared according to an embodiment of the present disclosure of zeolite I 27 Al solid nuclear magnetic resonance spectrum;

[0046] Figure 28 XRD pattern of zeolite K prepared according to a comparative example of the present disclosure;

[0047] Figure 29 prepared according to a comparative example of the present disclosure of zeolite K 29 Si solid nuclear magnetic resonance spectrum;

[0048] Figure 30 prepared according to a comparative example of the present disclosure of zeolite K 27 Al solid nuclear magnetic resonance spectrum;

[0049] Figure 31 XRD pattern of zeolite L prepared according to a comparative example of the present disclosure;

[0050] Figure 32 prepared according to a comparative example of the present disclosure of zeolite L 29 Si solid nuclear magnetic resonance spectrum;

[0051] Figure 33 27Al solid nuclear magnetic resonance spectrum of zeolite L prepared according to an embodiment of the present disclosure 27 ;

[0052] Figure 34 XRD pattern of zeolite M prepared according to a comparative example of the present disclosure.

[0053] Figure 35 29Si solid nuclear magnetic resonance spectrum of zeolite M prepared according to a comparative example of the present disclosure 29 ;

[0054] Figure 36 27Al solid nuclear magnetic resonance spectrum of zeolite M prepared according to a comparative example of the present disclosure 27 ;

[0055] Figure 37 XRD pattern of zeolite N prepared according to a comparative example of the present disclosure.

[0056] Figure 38 29Si solid nuclear magnetic resonance spectrum of zeolite N prepared according to a comparative example of the present disclosure 29 ;

[0057] Figure 39 27Al solid nuclear magnetic resonance spectrum of zeolite N prepared according to a comparative example of the present disclosure 27 ;

[0058] Figure 40 29Si solid nuclear magnetic resonance spectrum of zeolite O prepared according to a comparative example of the present disclosure 29 ;

[0059] Figure 41 27Al solid nuclear magnetic resonance spectrum of zeolite O prepared according to a comparative example of the present disclosure 27 ;

[0060] Figure 42 is a schematic diagram showing 29 the relationship between the chemical shift of Si in the 29Si solid nuclear magnetic resonance spectrum and the state of Si. Detailed Description of the Invention

[0061] Hereinafter, the inventive concept of the present disclosure will be further elaborated based on specific embodiments. However, the specific embodiments listed are for illustrative purposes only and are not intended to limit the scope of the present disclosure. Those skilled in the art will recognize that the specific features in any of the following embodiments can be used in any other embodiment as long as they do not deviate from the inventive concept described herein.

[0062] Vanadium-containing FER zeolite

[0063] All zeolites mentioned in this article refer to zeolites defined by the International Zeolite Association (hereinafter referred to as IZA), such as FER-type zeolites, MFI-type zeolites, FAU-type zeolites, etc. Zeolites usually have a regular network structure formed by the oxygen atoms at the vertices of the framework atom tetrahedrons (such as SiO 4 tetrahedron, AlO 4 tetrahedron or PO 4 tetrahedron) being connected by sharing, and the element atoms other than oxygen element are usually called non-oxygen atoms or T atoms. For FER-type zeolites, its structure can be determined by X-ray diffraction method (XRD), and at least the interplanar spacings shown in Table 1 below need to be detected That is, if it has the interplanar spacings shown in Table 1 below, then this zeolite can be a FER-type zeolite or a FER-type molecular sieve.

[0064] Table 1

[0065]

[0066] In the vanadium-containing FER-type zeolite provided in this article, it contains at least oxygen, aluminum, and silicon as the framework structure-forming atoms, and a part of the framework atoms can be replaced by elements other than the above-mentioned three elements. In one embodiment, the molar ratio of silicon atoms to aluminum atoms is 2 to 30:1, such as 2:1, 5:1, 10:1, 15:1, or 20:1.

[0067] The vanadium-containing FER-type zeolite described in this article, when analyzed by 29 29Si solid nuclear magnetic resonance spectroscopy, the peak area in the chemical shift range of -110 to -90 ppm accounts for more than 23% and less than 85% of the peak area in the chemical shift range of -125 to -90 ppm. Through research, it is found that zeolites with the above characteristics have high catalytic activity for alcohol-SCR denitrification. Generally, it is considered that 29 the characteristic peak in the chemical shift range of -110 to -90 ppm in the 29Si solid nuclear magnetic resonance spectroscopy reflects the information of framework silicon connected to framework Al. The higher the area ratio of the absorption peak in this interval, the more characteristic acid active sites the zeolite has, and thus the higher the catalytic activity of the zeolite for alcohol-SCR.

[0068] For FER-type zeolites, 29 the chemical shift of Si in the 29Si solid nuclear magnetic resonance spectroscopy reflects the local state of silicon atoms, that is, it can reflect the chemical form of Si in FER-type zeolites. Specifically, the applicant provides a schematic diagram to illustrate 29 the relationship between the chemical shift of Si in the 29Si solid nuclear magnetic resonance spectroscopy and the state of Si. As Figure 42 shown, the chemical environment of Si is represented by Qn (Q0 -Q 4 ) indicates that n is the number of oxygen atoms shared by each silicon-oxygen tetrahedron with adjacent tetrahedrons. Q 0 represents a monomer, Q 1 represents the end of a dimer or a long chain (with one shared oxygen atom), Q 2 represents Si with two shared oxygen atoms in the middle of a silicon chain, Q 3 represents Si with three shared oxygen atoms on the branch of a silicon chain, Q 4 represents a network structure (with four shared oxygen atoms). In the nuclear magnetic resonance Si spectrum, Q 0 has a corresponding chemical shift of -68 to -76 ppm, Q 1 has a corresponding chemical shift of -76 to -82 ppm, Q 2 has a corresponding chemical shift of -82 to -88 ppm, Q 3 has a corresponding chemical shift of -88 to -98 ppm, Q 4 has a corresponding chemical shift of -98 to -129 ppm. Therefore, in the 29 Si solid nuclear magnetic resonance spectrum of zeolite, the size of the Si nuclear magnetic signal area at different chemical shifts indicates the amount of Si atoms with a specific structure in the zeolite.

[0069] In some embodiments, the vanadium-containing FER-type zeolite contains at least silicon, aluminum, and oxygen as framework atoms, and the zeolite also contains vanadium, wherein the molar ratio of silicon atoms to aluminum atoms is 2 to 30:1, and based on the mass of the zeolite, the mass percentage of vanadium is 0.1 to 3%, and 29 when analyzed by Si solid nuclear magnetic resonance spectrum, the peak area in the chemical shift range of -110 to -90 ppm accounts for more than 23% and less than 85% of the peak area in the chemical shift range of -125 to -90 ppm.

[0070] In some embodiments, when the vanadium-containing FER-type zeolite is analyzed by 27 A1 solid nuclear magnetic resonance spectrum, the peak area in the chemical shift range of -50 to 40 ppm accounts for 60% or less of the peak area in the chemical shift range of -50 to 150 ppm.

[0071] The position where vanadium exists in the zeolite and its specific chemical valence state are not particularly limited. Vanadium can exist in the zeolite framework, outside the zeolite framework, or both inside and outside the zeolite framework. In some embodiments, the content of vanadium is 0.1% - 3%, for example, 0.1% - 2%, and can also be any value within the above range, such as 0.2%, 0.3%, 0.5%, 0.7%, 1%, 1.5%, 2% or 3%. When the content of vanadium element is less than 0.1%, there is a tendency for the low-temperature activity to decrease and the catalytic activity is insufficient. When the content of vanadium element exceeds 3%, it usually easily damages the acidic sites of the zeolite, resulting in a decrease in catalytic performance. The vanadium-containing FER-type zeolite may also contain other metal elements, such as one or more of alkali metals, alkaline earth metals, rare earth metals and transition metals, preferably other elements selected from one or more of titanium, zirconium, cerium, chromium, manganese, iron, cobalt, zinc, gallium, germanium, bismuth, arsenic, tin and boron. The position where other metal elements exist in the zeolite and their specific chemical valence state are not particularly limited. Other metal elements can exist in the zeolite framework or outside the zeolite framework. Based on the mass of the zeolite, the content of other metal elements can be 0.05% - 5%, for example, 0.1% - 3%, 0.5% - 1%, and can also be any value within the above range, such as 0.3%, 0.5%, 0.8%, 1%, 1.5%, 2%, 2.5% or 3%. The content of other element atoms accounts for 40% or less, preferably 30% or less, and further preferably 20% or less of the total number of moles of non-oxygen element atoms in the zeolite.

[0072] In some embodiments, cations exist outside the framework of the vanadium-containing FER-type zeolite of the present disclosure. The cations include hydrogen ions or ammonium ions. In some embodiments, the cations outside the framework further include one or more selected from alkali metal ions and alkaline earth metal ions. For example, it may include one or more of lithium, sodium, potassium, rubidium, cesium, calcium, magnesium, strontium and barium.

[0073] Preparation of vanadium-containing FER zeolite

[0074] The present disclosure provides a method for preparing the above-mentioned vanadium-containing FER-type zeolite, including: loading vanadium species onto a FER-type zeolite raw material to obtain a vanadium-containing FER-type zeolite.

[0075] In some embodiments, the method for preparing a vanadium-containing FER-type zeolite includes: removing alkali metal ions in the zeolite raw material by an ion exchange method for the FER-type zeolite raw material to obtain a treated zeolite, and then loading vanadium onto the treated zeolite to obtain the vanadium-containing FER-type zeolite; or loading vanadium onto an H-type or ammonium-type FER-type zeolite to obtain the vanadium-containing FER-type zeolite.

[0076] In some embodiments, a method for preparing a vanadium-containing FER-type zeolite includes: mixing a raw material of FER-type zeolite with a solution of a vanadium source, and then obtaining the vanadium-containing FER-type zeolite through separation, drying, grinding, and calcination. In some embodiments, the raw material of FER-type zeolite is selected from one of NH 4 type FER-type zeolite and H-type FER-type zeolite.

[0077] In some embodiments, the raw material of FER-type zeolite is prepared through the following steps: (1) mixing a silicon raw material, an aluminum raw material, an optional inorganic base AOH, and water to obtain an aqueous gel; (2) subjecting the aqueous gel to a hydrothermal synthesis reaction, and obtaining a zeolite primary product through separation, drying, and calcination as the raw material of the FER-type zeolite,

[0078] When the zeolite raw material obtained in step (2) contains alkali metal ions, the zeolite primary product is subjected to ion exchange with an ammonium salt to remove some or all of the alkali metal ions in the zeolite primary product, and then calcined to obtain the zeolite raw material.

[0079] In some embodiments, in step (1), the molar ratio of the silicon raw material: the aluminum raw material: the optional inorganic base AOH: water is 2 to 50SiO 2 :1Al 2 O 3 :2 to 20A 2 O: 200 to 2000H 2 O.

[0080] In some embodiments, the aluminum raw material can be one or more of aluminum sulfate, aluminum nitrate, sodium aluminate, sodium metaaluminate, alumina, aluminum hydroxide, boehmite, aluminum chloride, aluminosilicate gel, metallic aluminum, etc.

[0081] In some embodiments, during the preparation of the aqueous gel, the aluminum raw material is prepared as an aluminum raw material solution for use, and preferably, the above aluminum raw material is dissolved in water for preparation. Considering the ease of gel preparation and production efficiency, the concentration of the aluminum raw material solution is preferably 5 to 50% by weight, particularly preferably 10 to 40% by weight.

[0082] It should be noted that the aluminum raw material solution substantially does not contain silicon atoms. Here, "substantially does not contain" means that the silicon content in the aluminum raw material solution is 1% by weight or less, and preferably does not contain any.

[0083] In some embodiments, the silicon raw material can be one or more of colloidal silica, amorphous silica, fumed silica, white carbon black, water glass (sodium silicate), trimethylethoxysilane, tetraethyl orthosilicate, aluminosilicate gel, etc.

[0084] In some embodiments, if the silicon raw material is a liquid, it can be used as long as the silicon raw material is formulated into a silica aqueous dispersion of about 5 to 60% by weight like silica gel. When preparing other liquids containing a silicon raw material, it is preferably prepared into an aqueous solution or an aqueous dispersion with a silicon raw material concentration of 5% by weight or more, particularly 10% by weight or more, and 60% by weight or less, particularly 50% by weight or less. Similar to the aluminum raw material solution, the liquid of the silicon raw material substantially does not contain aluminum atoms. Here, "substantially does not contain" means that in the liquid containing the silicon raw material, the aluminum content is 1% by weight or less, and preferably does not contain any aluminum at all.

[0085] In some embodiments, as the inorganic base, one or more of alkali metal hydroxides such as sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide, the alkali component in the aluminate of the above aluminum raw material, the alkali component in the silicate of the above silicon raw material, or the alkali component in the silicate gel can be used. In some embodiments, the raw materials used also contain a metal raw material. In some other embodiments, a component having a crystallization promoting effect such as a seed crystal can also be added to the raw materials. During the manufacture of zeolite, as the alkali metal ion or alkaline earth metal ion, it is preferably at least one metal ion selected from the group consisting of lithium, sodium, potassium, rubidium, cesium, calcium, magnesium, strontium, and barium to perform crystallization. By including these alkali metal ions, crystallization is likely to occur and by-products (impurity crystals) are less likely to be generated. It should be noted that when calculating the molar ratio of the components in the gel, generally the corresponding oxide AO of the inorganic base AOH is used to calculate the molar ratio. 2 O is used to calculate the molar ratio.

[0086] In some embodiments, during the preparation of the aqueous gel, the inorganic base AOH is prepared as an inorganic base solution for use, and preferably the inorganic base solution is prepared by adding the inorganic base to water.

[0087] In some embodiments, an organic templating agent is also added to the raw materials for synthesizing the aqueous gel. A templating agent can be used to synthesize zeolites with a specific structure, and of course, it is also possible to synthesize FER-type zeolites without using a templating agent. In some embodiments, the organic templating agent is selected from one or more of ethylenediamine, isopropylamine, butylamine, octanediamine, cyclohexylimine, tetramethylammonium hydroxide, pyrrolidine, morpholine, N-methylmorpholine, piperidine, piperazine, N,N'-dimethylpiperazine, 1,4-diazabicyclo(2,2,2)octane, N-methylpiperidine, 3-methylpiperidine, quinuclidine, N-methylpyrrolidone, and hexamethyleneimine, methanol, ethanol, ethylene glycol, propanol, glycerol, isopropyl alcohol.

[0088] In some embodiments, an aqueous gel is prepared by uniformly mixing a silicon raw material solution, an aluminum raw material solution, and an inorganic base solution. According to another embodiment, a gel-like mixture is prepared by uniformly mixing a silicon raw material solution, an aluminum raw material solution, an inorganic base solution, an organic template agent, and a solution containing a metal raw material, which can be used as the aqueous gel for the next reaction. During the preparation of the gel-like mixture, the addition rate of each raw material solution is not limited and can be appropriately selected according to the use conditions.

[0089] In some embodiments, regarding the water content in the aqueous gel supplied to the hydrothermal synthesis reaction, considering the ease of zeolite crystal formation and manufacturing cost, the water content is 20% by weight or more, particularly 30% by weight or more and 80% by weight or less, particularly 70% by weight or less. The aqueous gel prepared as above can be subjected to hydrothermal synthesis immediately after preparation, but in order to obtain zeolite with high crystallinity, it is preferably aged for a specific time under specified temperature conditions. The aging temperature is usually 100 °C or lower, preferably 80 °C or lower, more preferably 60 °C or lower, and its lower limit is not particularly limited and is usually 0 °C or higher, preferably 10 °C or higher. For example, room temperature (25 °C) can be selected for aging. The aging temperature can be constant or gradually changing during aging. The aging time is not particularly limited and is usually 2 hours or more, 3 hours or more, 5 hours or more, 8 hours or more, or 12 hours or more, and is usually 30 days or less, 10 days or less, 4 days or less, 2 days or less, or 24 hours or less.

[0090] In some embodiments, the hydrothermal synthesis reaction is carried out as follows: The aqueous gel prepared as above is placed in a pressure-resistant container, and under autogenous pressure or gas pressure that does not hinder crystallization, under stirring conditions, or under conditions where the container is rotated or rocked, or in a static state, the temperature is maintained to carry out hydrothermal synthesis.

[0091] In some embodiments, the reaction temperature during hydrothermal synthesis is usually 90 °C or higher, preferably 120 °C or higher, more preferably 150 °C or higher, and usually 300 °C or lower, preferably 250 °C or lower, further preferably 220 °C or lower. The reaction time is not particularly limited and is usually 2 hours or more, 6 hours or more, 12 hours or more, or 24 hours or more, and is usually 30 days or less, 10 days or less, 7 days or less, 5 days or less, or 3 days or less. The reaction temperature can be constant or gradually changing during the reaction.

[0092] After the above hydrothermal synthesis, the zeolite as the product is separated from the hydrothermal synthesis reaction solution to obtain zeolite, which may contain one or more of an organic template agent or other alkali metals in the pores. The method for separating zeolite from the hydrothermal synthesis reaction solution is not particularly limited, and methods such as filtration, decantation, or direct drying can generally be listed.

[0093] In order to remove organic template agents and / or alkali metal ions used in the manufacturing process, the zeolite containing template agents, etc., separated and recovered from the hydrothermal synthesis reaction solution can be subjected to subsequent removal of template agents and alkali metal ions after washing with water and drying (for example, drying at 80°C to 100°C for 1 hour to 12 hours) as needed.

[0094] The removal treatment of template agents and / or alkali metals can be carried out by liquid-phase treatment using acidic solutions, chemical solutions containing template decomposition components, ion exchange treatment using resins, etc., thermal decomposition treatment, or these treatments can be used in combination. Generally, the contained organic substances (such as template agents) can be removed by calcination at a temperature of 300°C to 1000°C in an air or oxygen-containing inert gas atmosphere, or an inert gas atmosphere, or by extraction using organic solvents such as ethanol aqueous solution.

[0095] From the perspective of manufacturing, it is preferred to remove template agents, etc., by calcination. At this time, the calcination temperature is preferably 400°C or higher, more preferably 450°C or higher, further preferably 500°C or higher, preferably 900°C or lower, more preferably 850°C or lower, and further preferably 800°C or lower. An inert gas can be introduced during the calcination process. Gases such as nitrogen can be used, and inert components such as water vapor (for example, 5% to 10% water vapor) can also be added to the gas.

[0096] For the removal of alkali metal ions, the alkali metal part can be converted into the H form or NH 4 form by utilizing the ion exchange ability of the zeolite, and the method can adopt known techniques. It can be treated with ammonium salts such as NH 4 NO 3 , NH 4 Cl, (NH 4 ) 2 SO 4 or acidic solutions such as hydrochloric acid at room temperature to 100°C and then washed with water. In some embodiments, the NH 4 form of zeolite can be further converted into H-form zeolite by calcination. The calcination temperature is preferably 300°C or higher, more preferably 350°C or higher, further preferably 400°C or higher, preferably 900°C or lower, more preferably 800°C or lower, and further preferably 600°C or lower. An inert gas can be introduced during the calcination process. Gases such as nitrogen can be used, and inert components such as water vapor (for example, 5% to 10% water vapor) can also be added to the gas. Both NH 4 form and H-form FER-type zeolite can be used to prepare vanadium-containing FER-type zeolite.

[0097] In some embodiments, the vanadium source is selected from one or more of ammonium metavanadate, sodium metavanadate, potassium metavanadate, sodium orthovanadate, vanadyl sulfate, oxalovanadyl, vanadium tetrachloride, vanadium oxychloride, etc.

[0098] The solution of the vanadium source is prepared by dissolving the above vanadium source in a liquid to form a vanadium-containing solution. The vanadium source can be dissolved in water or in an organic solvent, such as one or more of methanol, ethanol, ethylene glycol, glycerol, toluene and other organic solvents. The pH value of the vanadium-containing solution is generally 1-14, preferably 1-13, and more preferably 2-12. This is because vanadium-containing solutions with too low or too high pH values are likely to cause damage or collapse of the zeolite framework during the mixing process with the zeolite, resulting in a decrease in the denitrification activity and thermal stability of the prepared catalyst.

[0099] In some embodiments, the mass ratio of the vanadium source (calculated as elemental vanadium): H-type or ammonium-type FER zeolite is 0.00-0.05 g V: 1 g H-type FER zeolite (for example, converting ammonium-type FER zeolite to H-type FER zeolite).

[0100] There is no particular limitation on the mixing method of the zeolite and the vanadium-containing solution. Generally, methods such as stirring and ultrasonic treatment can be used to mix the zeolite and the vanadium-containing solution evenly. The mixing temperature is generally between room temperature and 100 °C, preferably between room temperature and 80 °C, and more preferably between 50 and 80 °C. There is no particular limitation on the method for separating the zeolite after mixing. Generally, methods such as filtration, rotary evaporation or direct drying can be listed. Subsequently, the dried zeolite is calcined. The calcination temperature is preferably above 300 °C, more preferably above 350 °C, and further preferably above 400 °C, preferably below 900 °C, more preferably below 800 °C, and further preferably below 600 °C. The calcination time can be 1 hour to 6 hours, such as 2 hours, 3 hours, 4 hours or 5 hours. An inert gas can be introduced during the calcination process. Gases such as nitrogen can be used, or inert components such as water vapor (such as 5% to 10% water vapor) can be added to the gas.

[0101] There is no particular limitation on the calcination equipment of the present disclosure. Common industrial kilns such as muffle furnaces, tunnel kilns or rotary kilns can be used. Considering the convenience of continuous production, a rotary kiln is preferably used.

[0102] Application of vanadium-containing FER zeolite

[0103] The vanadium-containing FER zeolite of the present disclosure can be used directly in powder form or can be mixed with an adhesive to form a mixture containing the zeolite before use. The adhesives commonly used can be inorganic adhesives such as silica, alumina, zirconia or organic adhesives such as polysiloxanes. Polysiloxane-based organic adhesives refer to oligomers or polymers having a polysiloxane bond in the main chain, and also include substances in which a part of the substituents of the main chain having a polysiloxane bond is hydrolyzed to form hydroxyl groups. There is no particular limitation on the amount of the adhesive, which can generally be 1-20% by weight. Considering the strength during forming, it is 2-15% by weight.

[0104] The vanadium-containing FER zeolite of the present disclosure or a mixture containing such a zeolite can also be used after granulation or forming. The granulation or forming method is not particularly limited, and various known methods can be adopted. Generally, the zeolite mixture is formed and used as a formed body. The shape of the formed body can be various. For example, when the zeolite of the present disclosure is used as a catalyst for purifying nitrogen oxides in the exhaust gas of mobile sources (such as vehicles, ships, etc.), the method of applying the zeolite can be a coating method or a forming method to form the zeolite into a honeycomb catalyst. The coating method generally involves mixing the zeolite with an inorganic adhesive such as silica, alumina, or zirconia to make a slurry, and then coating it on the surface of a honeycomb made of an inorganic material such as cordierite, followed by drying and firing. The forming method generally involves kneading the zeolite with an inorganic adhesive such as silica or alumina or inorganic fibers such as alumina fibers or glass fibers, forming it into a honeycomb shape by an extrusion method or a compression method, and then drying and firing.

[0105] In some embodiments, the present disclosure provides a catalytic reactor for nitrogen oxide purification, which includes the vanadium-containing FER zeolite described in any of the foregoing embodiments or the vanadium-containing FER zeolite prepared by the method described in any of the foregoing embodiments as a denitration catalyst.

[0106] In some embodiments, the present disclosure provides a nitrogen oxide purification system, which includes the aforementioned catalytic reactor for nitrogen oxide purification.

[0107] In some embodiments, the present disclosure provides a denitration method, which includes using the vanadium-containing FER zeolite described in any of the foregoing embodiments or the vanadium-containing FER zeolite prepared by the method described in any of the foregoing embodiments as a denitration catalyst, and using an alcohol having 6 or less carbon atoms as a reducing agent for selective catalytic reduction denitration.

[0108] In some embodiments, the present disclosure provides the use of the vanadium-containing FER zeolite described in any of the foregoing embodiments or the vanadium-containing FER zeolite prepared by the method described in any of the foregoing embodiments as a catalyst in selective catalytic reduction denitration.

[0109] In some embodiments, the present disclosure provides the use of the vanadium-containing FER zeolite described in any of the foregoing embodiments or the vanadium-containing FER zeolite prepared by the method described in any of the foregoing embodiments as a catalyst in the process of selective catalytic reduction denitration using an alcohol having 6 or less carbon atoms as a reducing agent.

[0110] In some embodiments, the present disclosure provides a method for improving the low-temperature denitration performance and / or durability of FER zeolite, the method including loading vanadium on the FER zeolite.

[0111] When the vanadium-containing FER-type zeolite of the present disclosure is used as a catalyst, the zeolite purifies nitrogen oxides by contacting with exhaust gas containing nitrogen oxides. The nitrogen oxides to be purified include nitric oxide, nitrogen dioxide, nitrous oxide, etc. In this article, purifying nitrogen oxides means that the nitrogen oxides react on the catalyst and are converted into nitrogen, oxygen, etc. At this time, the nitrogen oxides can react directly, or for the purpose of improving the purification efficiency, coexist with a reducing agent in the catalyst. When using a reducing agent, the zeolite described in this article can make the purification reaction of nitrogen oxides easier to proceed. As long as the alcohol used as the reducing agent is a compound having a reducing ability at the temperature of the reduction treatment of industrial waste gas, it is preferable to use an alcohol having 6 or less carbon atoms as the reducing agent, for example, one or more selected from methanol, ethanol, ethylene glycol, propanol, glycerol, isopropanol, butanol, etc. In a preferred embodiment, the selected alcohols are methanol and ethanol. When using the vanadium-containing FER-type zeolite provided in this article as a catalyst, it is possible to purify the nitrogen oxides contained in various exhaust gases discharged from various gasoline and diesel engines, boilers, gas turbines, etc. used in diesel vehicles, gasoline vehicles, stationary power generation, ships, agricultural machinery, construction machinery, two- or three-wheeled motor vehicles, and aircraft.

[0112] Examples

[0113] The following examples are provided to facilitate a better understanding of the embodiments of the present disclosure, but are not used to make any limitations thereto. The experimental methods used in the following examples are all conventional methods unless otherwise specified, and the materials, reagents, etc. used can be obtained from commercial sources unless otherwise specified.

[0114] Solid-state nuclear magnetic resonance (NMR) measurement

[0115] The solid nuclear magnetic measurement instrument is a Bruker Avance III HD 400WB, 27 The resonance frequency of the Al NMR test is 104.3 MHz, the repetition time is 0.1 s, and the rotation frequency is 10 kHz. 29 The resonance frequency of the Si NMR test is 79.5 MHz, the repetition time is 6 s, and the rotation frequency is 5 kHz.

[0116] X-ray diffraction (XRD) measurement

[0117] The X-ray diffraction measurement instrument is Rigaku MiniFlex 600. The detection light source is Cu Kα, the tube voltage is 40 kV, the tube current is 40 mA, the detection angle range is 3 - 55°, and the scanning speed is 8° / min. The phase structure of the synthesized zeolite is determined by X-ray diffraction: The ground sample powder is added into the square hole on the glass plate, and then the glass plate is inserted into the axis position of the goniometer. Under the irradiation of the Cu Kα light source, the probe rotates at a speed of 2θ / min. θ(°) Chemical shift (ppm)

[0118] Evaluation method for catalyst activity

[0119] After the prepared zeolite is stamped into shape, it is crushed and sized. The sized zeolite (2 ml) is filled into an atmospheric-pressure fixed-bed flow-through reaction tube. At a rate of 1000 ml / min (space velocity SV = 30000 / hour), the gas with the composition shown in Table 2 is passed over the catalyst layer while heating the catalyst layer. At different temperatures, based on the outlet NO concentration, N 2 O concentration, and NO 2 concentration, the NOx removal activity of the catalyst is evaluated by the value of the following formula.

[0120] (NO conversion rate) = {(inlet NO concentration) - (outlet NO concentration)} / (inlet NO concentration)

[0121] Table 2

[0122] NO concentration 1000 ppm Methanol concentration 1500 ppm Nitrogen concentration Balance Water vapor concentration 5.0 vol% Oxygen concentration 14.0 vol% Gas flow rate 1 L / min Amount of catalyst 2ml Space velocity 30000 / h

[0123] Hydrothermal aging test

[0124] After the prepared zeolite is stamped into shape, it is crushed and sized. The sized zeolite (2 ml) is filled into an atmospheric-pressure fixed-bed flow-through reaction tube, and the catalyst layer is heated to 600 °C. At a rate of 1000 ml / min (space velocity SV = 30000 / hour), air containing 10% water vapor is passed over the catalyst layer for 12 hours.

[0125] Example 1

[0126] NH type FER zeolite (HSZ-720NHA, SiO 4 from TOSOH Corporation, Japan 2 / Al 2 O 3The H-type FER zeolite was obtained by calcining at 500 °C in air for 2 hours with a molar ratio of 18). Under the water bath condition of 60 °C, 0.0345 g of ammonium metavanadate was dissolved in 10.8 g of water to prepare an ammonium metavanadate aqueous solution. Subsequently, 3 g of the above-mentioned calcined H-type FER zeolite was added and stirred evenly. After rotary evaporation at 60 °C to remove water, the obtained powder was placed in a vacuum drying oven and dried at 100 °C for 12 h, then ground evenly, transferred to a muffle furnace and calcined at 500 °C for 4 h to obtain Zeolite A. The XRD measurement results of Zeolite A are as Figure 1 shown, which is a FER-type zeolite. The 29 29Si solid nuclear magnetic resonance spectrum of Zeolite A is as Figure 2 shown, and the peak area in the chemical shift range of -110 to -90 ppm accounts for 31% of the peak area in the chemical shift range of -125 to -90 ppm. The 27 27Al solid nuclear magnetic resonance spectrum of Zeolite A is as Figure 3 shown, and the peak area in the chemical shift range of -50 to 40 ppm accounts for 18% of the peak area in the chemical shift range of -50 to 150 ppm. The vanadium content of Zeolite A is 0.5 wt%. The catalytic activity results of methanol-SCR of Zeolite A are shown in Table 3. The catalytic activity results of methanol-SCR of Zeolite A after hydrothermal aging test are shown in Table 4.

[0127] Example 2

[0128] NH of TOSOH Corporation in Japan 4 type FER zeolite (HSZ-720NHA, SiO 2 / Al 2 O 3 with a molar ratio of 18) was calcined at 500 °C in air for 2 hours to obtain the H-type FER zeolite. Under the water bath condition of 60 °C, 0.052 g of ammonium metavanadate was dissolved in 10.8 g of water to prepare an ammonium metavanadate aqueous solution. Subsequently, 3 g of the above-mentioned calcined H-type FER zeolite was added and stirred evenly. After rotary evaporation at 60 °C to remove water, the obtained powder was placed in a vacuum drying oven and dried at 100 degrees for 12 h, then ground evenly, transferred to a muffle furnace and calcined at 500 °C for 4 h to obtain Zeolite B. The XRD measurement results of Zeolite B are as Figure 4 shown, which is a FER-type zeolite. The 29 29Si solid nuclear magnetic resonance spectrum of Zeolite B is as Figure 5 shown, and the peak area in the chemical shift range of -110 to -90 ppm accounts for 34% of the peak area in the chemical shift range of -125 to -90 ppm. The 27 27Al solid nuclear magnetic resonance spectrum of Zeolite B is as Figure 6As shown, the peak area in the chemical shift range of -50 to 40 ppm accounts for 11% of the peak area in the chemical shift range of -50 to 150 ppm. The vanadium content of Zeolite B is 0.75 wt%. The catalytic activity results of methanol-SCR of Zeolite B are shown in Table 3.

[0129] Example 3

[0130] TOSOH Corporation, Japan, NH 4 type FER zeolite (HSZ-720NHA, SiO 2 / Al 2 O 3 molar ratio 18) is calcined in air at 500 °C for 2 hours to obtain H-type FER zeolite. Under the water bath condition of 60 °C, 0.069 g of ammonium metavanadate is dissolved in 10.8 g of water to prepare an ammonium metavanadate aqueous solution. Subsequently, 3 g of the above-mentioned calcined H-type FER zeolite is added and stirred evenly. After rotary evaporation at 60 °C to remove water, the obtained powder is placed in a vacuum drying oven and dried at 100 °C for 12 h and then ground evenly. It is transferred to a muffle furnace and calcined at 500 °C for 4 h to obtain Zeolite C. The XRD measurement results of Zeolite C are as Figure 7 shown, which is FER-type zeolite. The 29 Si solid nuclear magnetic resonance spectrum of Zeolite C is as Figure 8 shown, and the peak area in the chemical shift range of -110 to -90 ppm accounts for 32% of the peak area in the chemical shift range of -125 to -90 ppm. The 27 Al solid nuclear magnetic resonance spectrum of Zeolite C is as Figure 9 shown, and the peak area in the chemical shift range of -50 to 40 ppm accounts for 18% of the peak area in the chemical shift range of -50 to 150 ppm. The vanadium content of Zeolite C is 1 wt%. The catalytic activity results of methanol-SCR of Zeolite C are shown in Table 3.

[0131] Example 4

[0132] 1.0988 g of NaAlO 2 , 0.2656 g of NaOH and 0.7496 g of KOH are dissolved in 54 g of water and stirred evenly to obtain a clear and transparent solution. Subsequently, 6 g of fumed silica is added to the above solution while stirring, and stirred evenly to obtain a gel. The gel composition is 1SiO 2 : 0.067Al 2 O 3 : 0.0332Na 2 O: 0.0668K 2 O: 30H 2O. After stirring and curing at room temperature for 12 hours, the gel was placed in a temperature- and pressure-resistant container. After hydrothermal synthesis at 165 °C for 72 hours, the reaction solution was cooled. The obtained powder was recovered by filtration, dried at 100 °C for 2 hours, then transferred to a muffle furnace and calcined at 600 °C in an air atmosphere for 6 hours to obtain Zeolite D1.

[0133] 1.3 g of ammonium chloride was dissolved in 13 g of water, and then 4 g of the obtained FER-type zeolite was added to form a slurry. The reaction was carried out at 80 °C for 2 hours for ion exchange. The reaction solution was cooled, and the obtained powder was recovered by filtration and dried at 100 °C for 2 hours. After repeating the above ion exchange 2 times, the obtained powder was calcined in air at 500 °C for 2 hours to obtain H-type Zeolite D2.

[0134] Under the water bath condition of 60 °C, 0.0345 g of ammonium metavanadate was dissolved in 10.8 g of water to prepare an ammonium metavanadate aqueous solution. Subsequently, 3 g of the above-mentioned calcined H-type Zeolite D2 was added and stirred evenly. After rotary evaporation at 60 °C to remove water, the obtained powder was placed in a vacuum drying oven and dried at 100 °C for 12 h, then ground evenly, transferred to a muffle furnace and calcined at 500 °C for 4 h to obtain Zeolite D. The XRD measurement results of Zeolite D are as Figure 10 shown, which is a FER-type zeolite. The 29 29Si solid nuclear magnetic resonance spectrum of Zeolite D is as Figure 11 shown, and the peak area in the chemical shift range of -110 to -90 ppm accounts for 42% of the peak area in the chemical shift range of -125 to -90 ppm. The 27 27Al solid nuclear magnetic resonance spectrum of Zeolite D is as Figure 12 shown, and the peak area in the chemical shift range of -50 to 40 ppm accounts for 16% of the peak area in the chemical shift range of -50 to 150 ppm. The SiO 2 / Al 2 O 3 molar ratio of Zeolite D is 17, and the vanadium content is 0.5 wt%. The catalytic activity results of methanol-SCR of Zeolite D are shown in Table 3.

[0135] Example 5

[0136] NH 4 -type FER-type zeolite (HSZ-720NHA, SiO 2 / Al 2 O 3After calcining at 500 °C in air for 2 hours, H-type FER zeolite was obtained. 0.103 g of ammonium metavanadate and 0.221 g of oxalic acid were dissolved in 10.8 g of water to prepare a vanadium-containing solution. Subsequently, 3 g of the calcined H-type FER zeolite obtained above was added, and after stirring evenly, the water was removed by suction filtration. The obtained powder was placed in a vacuum drying oven and dried at 100 °C for 12 h, then ground evenly, transferred to a muffle furnace and calcined at 500 °C for 4 h to obtain zeolite E. The XRD measurement results of zeolite E are as Figure 13 shown, which is FER-type zeolite. The 29 29Si solid nuclear magnetic resonance spectrum of zeolite E is as Figure 14 shown, and the peak area in the chemical shift range of -110 to -90 ppm accounts for 36% of the peak area in the chemical shift range of -125 to -90 ppm. The 27 27Al solid nuclear magnetic resonance spectrum of zeolite E is as Figure 15 shown, and the peak area in the chemical shift range of -50 to 40 ppm accounts for 12% of the peak area in the chemical shift range of -50 to 150 ppm. The vanadium content of zeolite E is 0.5 wt%. The catalytic activity results of methanol-SCR of zeolite E are shown in Table 3. The catalytic activity results of methanol-SCR of zeolite E after hydrothermal aging test are shown in Table 4.

[0137] Example 6

[0138] 1.367 g of solid sodium aluminate (Al 2 O 3 ≥45%) and 0.896 g of potassium hydroxide were dissolved in 40 g of deionized water to prepare a mixed solution, and then 20 g of silica sol was added dropwise to the stirred mixed solution and stirred evenly to obtain an aqueous gel. The composition of the aqueous gel is: 17SiO 2 :1Al 2 O 3 :1.39Na 2 O:1.32K 2 O:510H 2 O. After stirring and aging at room temperature for 12 hours, the aqueous gel was placed in a temperature and pressure resistant container, hydrothermally synthesized at 180 °C for 48 hours, and then the reaction solution was cooled. The obtained powder was filtered and recovered and dried at 100 °C for 2 hours to obtain zeolite F1.

[0139] 1.39 g of ammonium chloride was dissolved in 15 g of water, then 5 g of zeolite F1 was added to form a slurry, and the reaction was carried out at 80 °C for 2 hours for ion exchange. The reaction solution was cooled, the obtained powder was filtered and recovered, and dried at 100 °C for 2 hours. After repeating the above ion exchange 2 times, the obtained powder was calcined in air at 500 °C for 2 hours to obtain H-type zeolite F2.

[0140] Under the condition of a 60 °C water bath, 0.052 g of ammonium metavanadate was dissolved in 10.8 g of water to prepare an ammonium metavanadate aqueous solution. Subsequently, 3 g of the above-mentioned calcined zeolite F2 was added under the same conditions and mixed for 2 h. After rotary evaporation at 60 °C to remove water, the obtained powder was placed in a vacuum drying oven and dried at 100 °C for 12 h, then ground evenly, transferred to a muffle furnace and calcined at 500 °C for 4 h to obtain zeolite F. The XRD measurement results of zeolite F are as Figure 16 shown, which is a FER-type zeolite. The 29 29Si solid nuclear magnetic resonance spectrum of zeolite F is as Figure 17 shown, and the peak area in the chemical shift range of -110 to -90 ppm accounts for 47% of the peak area in the chemical shift range of -125 to -90 ppm. The 27 27Al solid nuclear magnetic resonance spectrum of zeolite F is as Figure 18 shown, and the peak area in the chemical shift range of -50 to 40 ppm accounts for 32% of the peak area in the chemical shift range of -50 to 150 ppm. The vanadium content of the zeolite is 0.5 wt%. The SiO 2 / Al 2 O 3 molar ratio of zeolite F is 12, and the vanadium content is 0.75 wt%. The catalytic activity results of methanol-SCR of zeolite F are shown in Table 3. The catalytic activity results of methanol-SCR of zeolite F after hydrothermal aging test are shown in Table 4.

[0141] Example 7

[0142] 1.367 g of solid sodium aluminate (Al 2 O 3 ≥45%) and 0.896 g of potassium hydroxide were dissolved in 40 g of deionized water to prepare a mixed solution, and then 20 g of silica sol was added dropwise to the stirred mixed solution and stirred evenly to obtain an aqueous gel. The composition of the aqueous gel is: 17SiO 2 :1Al 2 O 3 :1.39Na 2 O:1.32K 2 O:510H 2 O. After stirring and aging at room temperature for 12 hours, the aqueous gel was placed in a temperature and pressure resistant container, hydrothermally synthesized at 180 °C for 48 hours, and then the reaction solution was cooled. The obtained powder was filtered and recovered, dried at 100 °C for 2 hours to obtain zeolite G1.

[0143] Dissolve 1.39 g of ammonium chloride in 15 g of water, then add 5 g of zeolite G1 to form a slurry, and carry out ion exchange at 80 °C for 2 hours. Cool the reaction solution, filter to recover the obtained powder, and dry it at 100 °C for 2 hours. After repeating the above ion exchange 2 times, calcine the obtained powder in air at 500 °C for 2 hours to obtain H-type zeolite G2.

[0144] Under the condition of a 60 °C water bath, dissolve 0.069 g of ammonium metavanadate in 10.8 g of water to prepare an ammonium metavanadate aqueous solution. Subsequently, add 3 g of the above-mentioned calcined zeolite G2 and mix for 2 h under the same conditions. After rotary evaporation at 60 °C to remove water, put the obtained powder into a vacuum drying oven and dry it at 100 °C for 12 h, then grind it evenly, transfer it to a muffle furnace and calcine it at 500 °C for 4 h to obtain zeolite G. The XRD measurement results of zeolite G are as Figure 19 shown, which is FER-type zeolite. The 29 Si solid nuclear magnetic resonance spectrum of zeolite G is as Figure 20 shown, and the peak area in the chemical shift range of -110 to -90 ppm accounts for 48% of the peak area in the chemical shift range of -125 to -90 ppm. The 27 Al solid nuclear magnetic resonance spectrum of zeolite G is as Figure 21 shown, and the peak area in the chemical shift range of -50 to 40 ppm accounts for 36% of the peak area in the chemical shift range of -50 to 150 ppm. The SiO 2 / Al 2 O 3 molar ratio of zeolite G is 12, and the vanadium content is 1 wt%. The catalytic activity results of methanol-SCR of zeolite G are shown in Table 3.

[0145] Example 8

[0146] Dissolve 1.23 g of liquid sodium aluminate (Al 2 O 3 ≥50%) and 0.896 g of potassium hydroxide in 40 g of deionized water to form a mixed solution, and then drop 20 g of silica sol into the stirred mixed solution and stir evenly to obtain an aqueous gel. The composition of the aqueous gel is: 17SiO 2 :1Al 2 O 3 :1.24Na 2 O:1.32K 2 O:510H 2 O. After stirring and aging at room temperature for 12 hours, put the aqueous gel into a temperature- and pressure-resistant container, carry out hydrothermal synthesis at 180 °C for 48 hours, and then cool the reaction solution. Filter to recover the obtained powder and dry it at 100 °C for 2 hours to obtain zeolite H1.

[0147] Dissolve 1.39 g of ammonium chloride in 15 g of water, then add 5 g of zeolite H1 to form a slurry, and carry out ion exchange at 80 °C for 2 hours. Cool the reaction solution, filter to recover the obtained powder, and dry it at 100 °C for 2 hours. After repeating the above ion exchange 2 times, calcine the obtained powder in air at 500 °C for 4 hours to obtain H-type zeolite H2.

[0148] Under the condition of a 60 °C water bath, dissolve 0.0345 g of ammonium metavanadate in 10.8 g of water to prepare an ammonium metavanadate aqueous solution. Subsequently, add 3 g of the above-mentioned calcined zeolite H2 under the same conditions and mix for 2 h. After rotary evaporation at 60 °C to remove water, put the obtained powder into a vacuum drying oven and dry it at 100 °C for 12 h, then grind it evenly, transfer it to a muffle furnace and calcine it at 500 °C for 4 h to obtain zeolite H. The XRD measurement results of zeolite H are as Figure 22 shown, which is a FER-type zeolite. The 29 29Si solid nuclear magnetic resonance spectrum of zeolite H is as Figure 23 shown, and the peak area in the chemical shift range of -110 to -90 ppm accounts for 41% of the peak area in the chemical shift range of -125 to -90 ppm. The 27 27Al solid nuclear magnetic resonance spectrum of zeolite H is as Figure 24 shown, and the peak area in the chemical shift range of -50 to 40 ppm accounts for 22% of the peak area in the chemical shift range of -50 to 150 ppm. The SiO 2 / Al 2 O 3 molar ratio of zeolite H is 12, and the vanadium content is 0.5 wt%. The catalytic activity results of methanol-SCR of zeolite H are shown in Table 3.

[0149] Example 9

[0150] Dissolve 1.16 g of solid sodium aluminate (Al 2 O 3 ≥53%) and 0.896 g of potassium hydroxide in 37.9 g of deionized water to form a mixed solution, and then drop 20 g of silica sol into the stirred mixed solution and stir evenly to obtain an aqueous gel. The composition of the aqueous gel is: 17SiO 2 :1Al 2 O 3 :1.17Na 2 O:1.32K 2 O:510H 2 O. After stirring and aging at room temperature for 12 hours, put the aqueous gel into a temperature and pressure resistant container, carry out hydrothermal synthesis at 180 °C for 48 hours, and then cool the reaction solution. Filter to recover the obtained powder and dry it at 100 °C for 2 hours to obtain zeolite I1.

[0151] Dissolve 1.39 g of ammonium chloride in 15 g of water, then add 5 g of zeolite I1 to form a slurry, and carry out ion exchange at 80 °C for 2 hours. Cool the reaction solution, filter to recover the obtained powder, and dry it at 100 °C for 2 hours. After repeating the above ion exchange 2 times, calcine the obtained powder in air at 500 °C for 4 hours to obtain H-type zeolite I2.

[0152] Under the condition of a 60 °C water bath, dissolve 0.0345 g of ammonium metavanadate in 10.8 g of water to prepare an ammonium metavanadate aqueous solution. Subsequently, add 3 g of the zeolite I2 obtained by the above calcination and mix for 2 h. After rotary evaporation at 60 °C to remove water, put the obtained powder into a vacuum drying oven and dry it at 100 °C for 12 h, then grind it evenly, transfer it to a muffle furnace and calcine it at 500 °C for 4 h to obtain zeolite I. The XRD measurement results of zeolite I are as Figure 25 shown to be FER-type zeolite. The 29 29Si solid nuclear magnetic resonance spectrum of zeolite I is as Figure 26 shown, and the peak area in the chemical shift range of -110 to -90 ppm accounts for 42% of the peak area in the chemical shift range of -125 to -90 ppm. The 27 27Al solid nuclear magnetic resonance spectrum of zeolite I is as Figure 27 shown, and the peak area in the chemical shift range of -50 to 40 ppm accounts for 27% of the peak area in the chemical shift range of -50 to 150 ppm. The SiO 2 / Al 2 O 3 molar ratio of zeolite I is 12, and the vanadium content is 0.5 wt%. The catalytic activity results of methanol-SCR of zeolite I are shown in Table 3.

[0153] Example 10

[0154] Dissolve 1.39 g of ammonium chloride in 15 g of water, then add 5 g of zeolite I1 prepared in Example 9 to form a slurry, and carry out ion exchange at 80 °C for 2 hours. Cool the reaction solution, filter to recover the obtained powder, and dry it at 100 °C for 2 hours to obtain ammonium-type zeolite J2.

[0155] Under the condition of a 60 °C water bath, dissolve 0.0345 g of ammonium metavanadate in 10.8 g of water to prepare an ammonium metavanadate aqueous solution. Subsequently, add 3 g of ammonium-type zeolite J2 and mix for 2 h. After rotary evaporation at 60 °C to remove water, put the obtained powder into a vacuum drying oven and dry it at 100 °C for 12 h, then grind it evenly, transfer it to a muffle furnace and calcine it at 500 °C for 4 h to obtain zeolite J. The XRD measurement results of zeolite J are FER-type zeolite. The test results of the 29 29Si solid nuclear magnetic resonance spectrum of zeolite J show that the peak area in the chemical shift range of -110 to -90 ppm accounts for 42% of the peak area in the chemical shift range of -125 to -90 ppm. The27 The results of solid-state NMR of Al show that the peak area in the chemical shift range of -50 to 40 ppm accounts for 27% of the peak area in the chemical shift range of -50 to 150 ppm. For zeolite J, the SiO 2 / Al 2 O 3 molar ratio is 12 and the vanadium content is 0.5 wt%. The catalytic activity results of methanol-SCR over zeolite J are shown in Table 3.

[0156] Comparative Example 1

[0157] NH of TOSOH Corporation, Japan 4 type FER zeolite (HSZ-720NHA, SiO 2 / Al 2 O 3 molar ratio 18) was calcined in air at 500 °C for 2 hours to obtain zeolite K. The XRD measurement results of zeolite K are as Figure 28 shown, which is a FER type zeolite. The 29 Si solid-state NMR spectrum of zeolite K is as Figure 29 shown, and the peak area in the chemical shift range of -110 to -90 ppm accounts for 23% of the peak area in the chemical shift range of -125 to -90 ppm. The 27 Al solid-state NMR spectrum of zeolite K is as Figure 30 shown, and the peak area in the chemical shift range of -50 to 40 ppm accounts for 4% of the peak area in the chemical shift range of -50 to 150 ppm. The catalytic activity results of methanol-SCR over zeolite K are shown in Table 3.

[0158] Comparative Example 2

[0159] NH 4 type FAU zeolite (Tianjin Nanhua Catalyst Co., Ltd., SiO 2 / Al 2 O 3 molar ratio 5.2) was calcined in air at 500 °C for 2 hours to obtain H-type FAU zeolite. Under the water bath condition of 60 °C, 0.0345 g of ammonium metavanadate was dissolved in 10.8 g of water to prepare an ammonium metavanadate aqueous solution. Subsequently, 3 g of the above-mentioned calcined H-type FAU zeolite was added and stirred evenly. After rotary evaporation at 60 °C to remove water, the obtained powder was placed in a vacuum drying oven and dried at 100 °C for 12 h and then ground evenly. It was transferred to a muffle furnace and calcined at 500 °C for 4 h to obtain zeolite L. The XRD measurement results of zeolite L are as Figure 31 shown, which is a FAU type zeolite. The 29 Si solid-state NMR spectrum of zeolite L is as Figure 32As shown, the peak area in the chemical shift range of -110 to -90 ppm accounts for 86% of the peak area in the chemical shift range of -125 to -90 ppm. For Zeolite L, 27 the solid-state NMR spectrum of Al is as Figure 33 shown, and the peak area in the chemical shift range of -50 to 40 ppm accounts for 30% of the peak area in the chemical shift range of -50 to 150 ppm. The vanadium content of Zeolite L is 0.5 wt%. The catalytic activity results of methanol-SCR of Zeolite L are shown in Table 3.

[0160] Comparative Example 3

[0161] NH 4 type MFI zeolite (Tianjin Nanhua Catalyst Co., Ltd., SiO 2 / Al 2 O 3 molar ratio 38) is calcined in air at 500 °C for 2 hours to obtain H-type MFI zeolite. Under the water bath condition of 60 °C, 0.0345 g of ammonium metavanadate is dissolved in 10.8 g of water to prepare an ammonium metavanadate aqueous solution. Subsequently, 3 g of the above-mentioned calcined H-type MFI zeolite is added and stirred evenly. After rotary evaporation at 60 °C to remove water, the obtained powder is placed in a vacuum drying oven and dried at 100 °C for 12 h and then ground evenly. It is transferred to a muffle furnace and calcined at 500 °C for 4 h to obtain Zeolite M. The XRD measurement results of Zeolite M are as Figure 34 shown, which is MFI-type zeolite. The 29 solid-state NMR spectrum of Si in Zeolite M is as Figure 35 shown, and the peak area in the chemical shift range of -110 to -90 ppm accounts for 21% of the peak area in the chemical shift range of -125 to -90 ppm. The 27 solid-state NMR spectrum of Al in Zeolite M is as Figure 36 shown, and the peak area in the chemical shift range of -50 to 40 ppm accounts for 19% of the peak area in the chemical shift range of -50 to 150 ppm. The vanadium content of Zeolite M is 0.5 wt%. The catalytic activity results of methanol-SCR of Zeolite M are shown in Table 3.

[0162] Comparative Example 4

[0163] 1.23 g of solid sodium aluminate (Al 2 O 3 ≥50%) and 0.896 g of potassium hydroxide are dissolved in 40 g of deionized water to prepare a mixed solution. Then, 20 g of silica sol is added dropwise to the stirred mixed solution and stirred evenly to obtain an aqueous gel. The composition of the aqueous gel is: 17SiO 2 :1Al 2 O 3 :1.4Na 2 O:1.32K2 O:510H 2 O. After stirring and curing at room temperature for 12 hours, the aqueous gel was placed in a temperature- and pressure-resistant container. After hydrothermal synthesis at 180 °C for 48 hours, the reaction solution was cooled. The obtained powder was recovered by filtration and dried at 100 °C for 2 hours to obtain zeolite N1.

[0164] 1.3 g of ammonium chloride was dissolved in 13 g of water, and then 4 g of zeolite N1 was added to form a slurry. The ion exchange was carried out at 80 °C for 2 hours. The reaction solution was cooled, the obtained powder was recovered by filtration, and dried at 100 °C for 2 hours. After repeating the above ion exchange twice, the obtained powder was calcined in air at 500 °C for 2 hours to obtain zeolite N. The XRD measurement results of zeolite N are as Figure 37 shown, which is a FER-type zeolite. The 29 29Si solid nuclear magnetic resonance spectrum of zeolite N is as Figure 38 shown, and the peak area in the chemical shift range of -110 to -90 ppm accounts for 44% of the peak area in the chemical shift range of -125 to -90 ppm. The 27 27Al solid nuclear magnetic resonance spectrum of zeolite N is as Figure 39 shown, and the peak area in the chemical shift range of -50 to 40 ppm accounts for 13% of the peak area in the chemical shift range of -50 to 150 ppm. The SiO 2 / Al 2 O 3 molar ratio of zeolite N is 12. The catalytic activity results of methanol-SCR of zeolite N are shown in Table 3.

[0165] Comparative Example 5

[0166] FER-type zeolite O was obtained according to the preparation method of Example 2 in Patent Document WO2021 / 114208A1. The 29 29Si solid nuclear magnetic resonance spectrum of zeolite O is as Figure 40 shown, and the peak area in the chemical shift range of -110 to -90 ppm accounts for 36% of the peak area in the chemical shift range of -125 to -90 ppm. The 27 27Al solid nuclear magnetic resonance spectrum of zeolite O is as Figure 41 shown, and the peak area in the chemical shift range of -50 to 40 ppm accounts for 23% of the peak area in the chemical shift range of -50 to 150 ppm. The catalytic activity results of methanol-SCR of zeolite O are shown in Table 3.

[0167] The catalytic activity results of methanol-SCR of zeolite O after hydrothermal aging test are shown in Table 4.

[0168] Comparative Example 6

[0169] 0.28 g of oxalic acid was dissolved in 6 g of water, 0.13 g of ammonium metavanadate and 0.54 g of ammonium metatungstate were added, and after mixing evenly, 10 g of anatase titanium dioxide powder was added. After stirring for 2 h, it was placed in a drying oven and dried and ground evenly at 110 °C, then transferred to a muffle furnace and calcined at 500 °C for 4 h to obtain vanadium-based oxide P, and its vanadium content was 1 wt%.

[0170] Table 3

[0171]

[0172]

[0173] Table 4

[0174]

[0175] From the results of the above-mentioned examples and comparative examples, it can be seen that all the examples of the vanadium-containing FER-type zeolite denitration catalyst of the present disclosure adopt 29 When analyzed by Si solid nuclear magnetic resonance spectroscopy, the peak area in the chemical shift range of -110 to -90 ppm accounts for more than 23% and less than 85% of the peak area in the chemical shift range of -125 to -90 ppm. Compared with the vanadium-free zeolites (Comparative Examples 1 and 4) in which the peak area in the chemical shift range of -110 to -90 ppm accounts for more than 23% and less than 85% of the peak area in the chemical shift range of -125 to -90 ppm, and the vanadium-containing zeolites (Comparative Examples 2 and 3) in which the peak area in the chemical shift range of -110 to -90 ppm accounts for more than 85% and less than 23% of the peak area in the chemical shift range of -125 to -90 ppm, the examples of the present disclosure all show better methanol-SCR denitration performance at low temperatures (225 - 275 °C). Compared with the vanadium-free zeolite (Comparative Example 5) prepared in Example 2 disclosed in Patent Document WO2021114208A1, the examples of the present disclosure can also achieve better methanol-SCR denitration performance under low temperature conditions (225 - 275 °C).

[0176] Although the embodiments described herein are described with reference to specific embodiments, it should be understood that those skilled in the art will make various adjustments and changes to them as long as they do not violate the scope and spirit of the present disclosure.

Claims

1. Vanadium-containing FER zeolite, characterized in that, the zeolite contains at least silicon, aluminum and oxygen as framework atoms, wherein the molar ratio of silicon atoms to aluminum atoms is 2 to 30:1, wherein, based on the mass of the zeolite, the mass percentage content of vanadium is 0.1 to 3%, and When analyzing the zeolite by 29 Si solid nuclear magnetic resonance spectroscopy, the peak area in the chemical shift range of -110 to -90 ppm accounts for more than 23% and less than 85% of the peak area in the chemical shift range of -125 to -90 ppm.

2. The vanadium-containing FER zeolite according to claim 1, wherein, When analyzing the zeolite by 27 solid-state Al nuclear magnetic resonance spectroscopy, the peak area in the chemical shift range of -50 to 40 ppm accounts for less than 60% of the peak area in the chemical shift range of -50 to 150 ppm.

3. The vanadium-containing FER zeolite according to claim 1, wherein, vanadium is in the framework of the zeolite and / or outside the framework of the zeolite, for example, outside the framework of the zeolite.

4. The vanadium-containing FER zeolite according to any one of claims 1-3, wherein, cations exist outside the framework of the zeolite, for example, the cations are hydrogen ions or ammonium ions.

5. A method for preparing the vanadium-containing FER zeolite according to any one of claims 1-4, characterized in that, the method includes: removing alkali metal ions in the zeolite raw material by ion exchange method for the FER zeolite raw material to obtain the treated zeolite, and then loading vanadium on the treated zeolite to obtain the vanadium-containing FER zeolite; or loading vanadium on the H-type or ammonium-type FER zeolite to obtain the vanadium-containing FER zeolite.

6. The method according to claim 5, wherein, the vanadium is provided by a vanadium source, and the vanadium source is selected from ammonium metavanadate, sodium metavanadate, potassium metavanadate, sodium orthovanadate, vanadyl sulfate, oxalic acid vanadyl, vanadium tetrachloride, vanadium oxychloride or any combination thereof. Preferably, the vanadium source is in the form of a solution, and more preferably, the vanadium source is in the form of an aqueous solution; Optionally, the mass ratio of the vanadium source: the H-type or ammonium-type FER zeolite is 0.0005-0.05 g V: 1 g of the H-type FER zeolite.

7. A catalytic reactor for purifying nitrogen oxides, characterized in that, the catalytic reactor contains the vanadium-containing FER zeolite according to any one of claims 1 to 4 or the vanadium-containing FER zeolite prepared by the method according to claim 5 or 6 as a denitration catalyst.

8. A nitrogen oxide purification system, characterized in that, the nitrogen oxide purification catalytic reactor according to claim 7 is provided in the system.

9. A denitration method, characterized in that, the method includes using the vanadium-containing FER zeolite according to any one of claims 1 to 4 or the vanadium-containing FER zeolite prepared by the method according to claim 5 or 6 as a denitration catalyst, and using an alcohol with 6 or less carbon atoms as a reducing agent for selective catalytic reduction denitration.

10. A method for improving the low-temperature denitration performance and / or durability of FER zeolite, characterized in that, the method includes loading vanadium on the FER zeolite.

Images