Preparation method and application of molecular sieve based honeycomb catalyst with annular holes

Abstract

The invention discloses a preparation method and application of a molecular sieve based honeycomb catalyst with annular holes. The preparation method comprises the following steps: mixing a starch aqueous solution, an alcoholic solution and an acid solution, heating, depolymerizing and cross-linking, adding a molecular sieve catalyst, and flocculating and coating to obtain composite slurry; mixing natural silicon-aluminum minerals and an inorganic binder in advance, adding the mixture into the composite slurry, kneading, pugging, aging, performing extrusion molding, drying and calcining to obtain the molecular sieve-based honeycomb catalyst with the annular holes. According to the invention, starch is subjected to depolymerization and crosslinking by adopting a flocculating settling coating technology to form a crosslinked network structure, a molecular sieve catalyst is added to obtain composite slurry, the viscosity is increased, the composite slurry is coated on the surface of the molecular sieve catalyst after flocculating settling, and the composite slurry is removed after roasting to form an annular pore structure. According to the method, the molecular sieve catalyst can be protected in the forming process, the pore channel structure of the carrier can be improved after roasting, mass transfer limitation is reduced, and activity accessibility is improved.

Description

Technical Field

[0001] This invention belongs to the field of nitrogen oxide removal technology, specifically relating to a method for preparing a molecular sieve-based honeycomb catalyst with annular pores and its application. Background Technology

[0002] Nitrogen oxides cause a series of environmental problems, including acid rain, photochemical smog, and the greenhouse effect, posing a significant threat to human health, the environment, and even the socio-economic development. Selective catalytic reduction (NH3-SCR) technology, using ammonia as a reducing agent, is the most mature and widely used. Molecular sieve catalysts, due to their unique pore structure, tunable acidity, and excellent hydrothermal stability, exhibit good catalytic activity in the removal of nitrogen oxides, thus attracting widespread attention from researchers.

[0003] In practical denitrification applications, molecular sieve catalysts are selected as active components and molded with suitable supports. When using extrusion molding technology, the protection of molecular sieve catalysts is particularly important. At the same time, the diverse pore structures are also very important for the reaction.

[0004] CN 1156412 C describes the preparation of honeycomb ceramics using composite materials. A microcrystalline uniformly distributed body is obtained through a solid-phase reaction at a sintering temperature of 1300–1400℃, exhibiting characteristics such as thin pore walls, high pore density, and high strength, making it suitable for actual automotive operating conditions. CN 120127132 A describes the preparation of hierarchical porous carbon microspheres using spray drying technology, creating a three-dimensional porous carbon framework to construct a high-specific-capacity, high-stability room-temperature sodium-sulfur battery cathode material. CN 105013474 A describes the preparation of various single-component metal oxide and multi-component metal oxide denitration catalysts by mixing mesoporous silica templates with metal salts and potassium nitrate, followed by calcination and template removal. These catalysts feature uniform distribution of active components and a wide catalytic temperature window.

[0005] In the process of forming a honeycomb catalyst, it is necessary to introduce a suitable pore structure, and at the same time, it is also necessary to protect the molecular sieve catalyst. Summary of the Invention

[0006] The purpose of this invention is to provide a method for preparing a molecular sieve-based honeycomb catalyst with annular pores and its application. This method, during the formation of the honeycomb catalyst, effectively protects the molecular sieve catalyst while creating an annular pore structure to promote mass transfer and improve the catalyst's activity accessibility.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A method for preparing a molecular sieve-based honeycomb catalyst with annular pores includes the following steps:

[0009] (1) Mix starch aqueous solution, alcohol solution and acid, and then heat to depolymerize and crosslink, to obtain a mixed solution;

[0010] (2) Add molecular sieve catalyst to the above mixed solution, and obtain composite slurry after flocculation and coating;

[0011] (2) Natural silica-alumina minerals and inorganic binders are premixed and then added to the above composite slurry. After kneading, slurrying, aging, extrusion molding, drying and calcination, a molecular sieve-based honeycomb catalyst with annular pores is obtained.

[0012] This invention employs a flocculation and sedimentation coating technology to depolymerize and crosslink starch, forming a crosslinked network structure. After adding a molecular sieve catalyst, a composite slurry is obtained, increasing its viscosity. The slurry coats the surface of the molecular sieve catalyst after flocculation and sedimentation, and is then removed after calcination, forming a ring-shaped porous structure. This method protects the molecular sieve catalyst during the forming process and improves the carrier pore structure after calcination, reducing mass transfer limitations and enhancing activity accessibility.

[0013] The starch in the starch aqueous solution in step (1) is corn starch, lotus root starch, potato starch, mung bean starch, kudzu root starch, sweet potato starch, wheat starch or pea starch. The mass fraction of starch in the starch aqueous solution is 0.1-70.0%. The water in the starch aqueous solution is one or more of deionized water, pure water or mineral water.

[0014] The alcohol in the alcohol solution mentioned in step (1) is an alcohol compound such as ethanol, polyethylene glycol, ethylene glycol, or polyethylene glycol, and the mass fraction of alcohol in the alcohol solution is 0.1% to 90.0%.

[0015] The acid mentioned in step (1) is one or more of the following: nitric acid, sulfuric acid, hydrochloric acid, fruit acid, acetic acid, boric acid, carbonic acid, phosphoric acid, citric acid, tartaric acid, malic acid, oxalic acid, and lactic acid.

[0016] The method for preparing the mixed solution in step (1) is as follows: starch aqueous solution and alcohol solution are mixed evenly at a mass ratio of 1:0.3 to 10, acid is added to control the pH to 1 to 3, and the mixture is stirred and heated at 80 to 110°C for 0.5 to 12 hours to depolymerize.

[0017] The molecular sieve catalyst mentioned in step (2) is one or more of ZSM-5 molecular sieve, SSZ-39 molecular sieve, SSZ-13 molecular sieve, SAPO-11 molecular sieve, ZSM-35 molecular sieve, SAPO-34 molecular sieve, SAPO-47 molecular sieve, Y-type molecular sieve, Beta molecular sieve, KFI type molecular sieve, and mordenite (MOR), and the molar ratio of silica to alumina in the molecular sieve is 2 to 300:1; the metal element contained in the molecular sieve catalyst is one or more of iron, copper, manganese, cerium, lanthanum, rhodium, ruthenium, palladium, and osmium, and the content of the metal element is 0.1 to 10.0 wt%.

[0018] The composite slurry preparation process described in step (2) is as follows: under continuous stirring, a molecular sieve catalyst is added to the mixed solution, with the molecular sieve catalyst accounting for 0.5–70.0 wt% by mass; the viscosity increases during the composite process, and the viscosity is controlled to be 1 × 10⁻⁶. 2 ~1×10 5 Pa·s, sedimentation and stratification occurred after standing for 1 to 4 hours. After flocculation and coating, the composite slurry served as both a binder and a protector of the molecular sieve catalyst.

[0019] The natural silica-alumina minerals mentioned in step (3) are one or more of the following: pyrophyllite, kaolinite, palygorskite, jadeite, beryl, muscovite, serpentine, nepheline, illite, palygorskite, feldspar, spodumene, diatomite, talc, sepiolite, perlite, phlogopite, vermiculite, leucite, enstatite, diopside, amphibole, olivine, montmorillonite, kaolinite, diatomite, and attapulgite. The impurities (substances other than alumina and silicon dioxide) in the natural silica-alumina minerals are less than 20 wt%, and the particle size is not less than 200 mesh.

[0020] The inorganic binder mentioned in step (3) is one or more of silica sol, water glass, boehmite, or alumina sol.

[0021] Preferably, the mass ratio of each additive is: composite slurry: natural silica-alumina mineral: inorganic binder = 1~50: 1~80: 0.1~10.

[0022] The pre-mixing time in step (3) is 30-120 min, the kneading is stirring and mixing for 30-120 min, the number of kneading times is 2-5 times, the aging time is 1-10 days, the extrusion molding is a twin-screw extrusion or hydraulic extrusion, and the drying is drying the extruded material at a constant temperature of 80-110℃ to remove water and reach a constant weight.

[0023] The calcination method described in step (3) adopts a low-rate plateau heating method: the heating rate is 0.5 to 2℃ / min, the temperature is raised from room temperature to 180 to 400℃, held for 2 to 5 hours, and then raised to 550 to 800℃ for calcination for 6 to 12 hours.

[0024] The aforementioned molecular sieve-based honeycomb catalyst with annular pores can be applied to the NH3-SCR reaction.

[0025] Compared with the prior art, the advantages of the present invention are as follows:

[0026] This invention employs a flocculation coating technology to introduce molecular sieve catalysts in the form of a composite slurry during the honeycomb catalyst molding process. This technology improves the viscosity of the composite slurry, reduces the need for additional additives, and allows for flocculation and sedimentation after settling, effectively protecting the molecular sieve catalyst. Calcination removes the catalyst, forming an annular pore structure, reducing diffusion limitations, effectively improving activity accessibility, and providing a wider activity temperature window. The molecular sieve-based honeycomb catalyst of this invention reduces mass transfer limitations, is protected during molding, and effectively removes nitrogen oxides, demonstrating promising industrial application prospects. Attached Figure Description

[0027] Figure 1 The annular pore distribution of the catalyst prepared in Example 1 is shown in (a) before calcination and (b) after calcination. Detailed Implementation

[0028] The present invention will be further described below with reference to specific embodiments, which are intended to illustrate the implementation schemes and features of the present invention in detail, and should not be construed as limiting the present invention in any way.

[0029] The FeCu-ZSM-5 molecular sieve in the examples is a high-performance denitrification molecular sieve synthesized in situ using a one-pot method. It belongs to the bimetallic molecular sieve catalyst category. The introduction of Cu can not only regulate the framework Fe 3+ The acidity of molecular sieves can also enhance their redox capabilities, isolating Cu. 2+ Higher skeleton Fe 3+ Molecular sieve catalysts with good redox properties and acidity exhibit good denitrification catalytic activity (CN 109317188A)(ZL201811354909.1).

[0030] The natural aluminosilicate mineral kaolin used in the examples (purchased from China Kaolin Company, particle size less than 300 mesh) had a SiO2 content of 48.0% and an Al2O3 content of 37.0%.

[0031] Example 1

[0032] A method for preparing a molecular sieve-based honeycomb catalyst with annular pores for nitrogen oxide removal includes the following steps:

[0033] Weigh the following raw materials according to the following proportions based on their weight;

[0034] 90 parts corn starch, 45 parts polyethylene glycol, 225 parts deionized water, 5 parts citric acid, 7 parts nitric acid, 225 parts FeCu-ZSM-5 molecular sieve, 225 parts natural silica-alumina mineral kaolin, and 45 parts silica sol.

[0035] (1) Prepare corn starch into a starch solution with a corn starch content of 50 wt% and prepare polyethylene glycol into an alcohol solution with a mass content of 25 wt%. The mass ratio is required to be as follows: starch aqueous solution: alcohol solution = 1:1. Mix the two, add citric acid and nitric acid to control the pH to 2, and stir and heat at 97°C for 2 hours to depolymerize and obtain a mixed solution.

[0036] (2) The mixed solution was mixed with 225 parts of FeCu-ZSM-5 molecular sieve, and the mixture was stirred continuously during the mixing process, with the viscosity controlled at 1×10⁻⁶. 2 ~1×10 5 Pa·s yields the composite slurry:

[0037] (3) Take 225 parts of natural kaolinite and 45 parts of silica sol, add them to a mixer and dry mix them to obtain a mixed dry material;

[0038] (4) Add the mixed dry materials to the composite slurry and knead for 3 hours to obtain well kneaded mud.

[0039] (5) Knead the clay repeatedly 3 times;

[0040] (6) Seal the mud with plastic wrap and place it in a dry and cool place to age for 3 days;

[0041] (7) Put the clay into the molding machine and extrude it into shape;

[0042] (8) Place the formed honeycomb in a 105℃ oven to remove residual water until constant weight;

[0043] (9) The dried material is placed in a muffle furnace for calcination. The calcination curve is as follows: the temperature is increased from room temperature, controlled at 0.5℃ per minute, and then increased to 300℃ and held for 2 hours. The temperature is then increased to 600℃ and held for 10 hours to obtain a molecular sieve-based honeycomb catalyst with annular pores.

[0044] (10) The prepared molecular sieve-based honeycomb catalyst with annular pores was granulated, and the particle size was controlled to be 10-15 mesh. The catalyst was evaluated by simulating flue gas components N2, NH3, NO, O2, and H2O in small samples with a space velocity of 60,000 h⁻¹. -1 [NO] = [NH3] = 500ppm, [O2] = 5%, H2O = 5%. The NO concentrations at the inlet and outlet were measured respectively, and the denitrification efficiency of the catalyst was calculated.

[0045] Example 2

[0046] A method for preparing a molecular sieve-based honeycomb catalyst with annular pores for nitrogen oxide removal includes the following steps:

[0047] Weigh the following raw materials according to the following proportions based on their weight;

[0048] 90 parts potato starch, 45 parts ethylene glycol, 225 parts deionized water, 3 parts fruit acid, 10 parts hydrochloric acid, 225 parts FeCu-ZSM-5 molecular sieve, 225 parts natural silica-alumina mineral kaolin, and 45 parts pseudoboehmite.

[0049] (1) Potato starch is prepared into a starch solution in advance, with potato starch accounting for 50wt% and ethylene glycol is prepared into an alcohol solution in advance, with ethylene glycol accounting for 25wt%. The mass ratio is required to be as follows: starch aqueous solution: alcohol solution = 1:1. The two are mixed, and fruit acid and hydrochloric acid are added to control the pH of the mixed solution to 1. The mixture is stirred and heated at 95℃ for 4 hours to depolymerize and obtain the mixed solution.

[0050] (2) Mix the above mixed solution with 225 parts of FeCu-ZSM-5 molecular sieve, stirring continuously during the mixing process, and controlling the viscosity to 1×10. 2 ~1×10 5 Pa·s, to obtain composite slurry;

[0051] (3) Take 225 parts of natural silica-alumina mineral kaolin and 45 parts of boehmite, add them to a mixer for dry mixing to obtain a mixed dry material;

[0052] (4) Add the mixed dry materials to the composite slurry and knead for 3 hours to obtain well kneaded mud.

[0053] (5) Knead the clay repeatedly 3 times;

[0054] (6) Seal the mud with plastic wrap and let it age in a dry and cool place for 2 days;

[0055] (7) Put the clay into the molding machine and extrude it into shape;

[0056] (8) Place the formed honeycomb in a 100℃ oven to remove residual water until constant weight;

[0057] (9) The dried material is placed in a muffle furnace for calcination. The calcination curve is as follows: the temperature is raised from room temperature, controlled to increase by 0.5°C per minute, raised to 300°C and held for 2 hours, and then raised to 600°C and held for 10 hours to obtain a molecular sieve-based honeycomb catalyst with annular pores.

[0058] (10) The prepared molecular sieve-based honeycomb catalyst with annular pores was granulated, and the particle size was controlled to be 10-15 mesh. The catalyst was evaluated by simulating flue gas components N2, NH3, NO, O2, and H2O in small samples with a space velocity of 60,000 h⁻¹. -1 [NO] = [NH3] = 500ppm, [O2] = 5%, H2O = 5%. The NO concentrations at the inlet and outlet were measured respectively, and the denitrification efficiency of the catalyst was calculated.

[0059] Example 3

[0060] A method for preparing a molecular sieve-based honeycomb catalyst with annular pores for nitrogen oxide removal includes the following steps:

[0061] Weigh the following raw materials according to the following proportions based on their weight;

[0062] 90 parts lotus root starch, 45 parts ethanol, 225 parts deionized water, 6 parts lactic acid, 5 parts nitric acid, 225 parts FeCu-ZSM-5 molecular sieve, 225 parts natural silica-alumina mineral kaolin, and 45 parts aluminum sol.

[0063] (1) Prepare lotus root powder into a starch solution in advance, with lotus root powder accounting for 50 wt% and prepare ethanol into an alcohol solution in advance, with ethanol accounting for 25 wt%; the required mass ratio is as follows: starch aqueous solution: alcohol solution = 1:1. Mix the two, add lactic acid and nitric acid to control the pH to 1, stir and heat at 100℃ to depolymerize for 4 hours to obtain mixed dry material.

[0064] (2) The mixed solution was mixed with 225 parts of FeCu-ZSM-5 molecular sieve, and the mixture was stirred continuously during the mixing process, with the viscosity controlled at 1×10⁻⁶. 2 ~1×10 5 Pa·s yields the composite slurry:

[0065] (3) Take 225 parts of natural silica-alumina mineral kaolin and 45 parts of aluminum sol, add them to a mixer for dry mixing to obtain a mixed dry material;

[0066] (4) Add the mixed dry materials to the composite slurry and mix for 5 hours to obtain the well-mixed mud.

[0067] (5) Knead the kneaded clay repeatedly twice;

[0068] (6) Seal the mud with plastic wrap and place it in a dry and cool place to age for 5 days;

[0069] (7) Put the clay into the molding machine and extrude it into shape;

[0070] (8) Place the formed honeycomb in a 100℃ oven to remove residual water until constant weight;

[0071] (9) The dried material is placed in a muffle furnace for calcination. The calcination curve is as follows: the temperature is increased by 0.5°C per minute, the temperature is increased from room temperature to 300°C and held for 2 hours, and then the temperature is increased to 600°C and held for 10 hours to obtain a molecular sieve-based honeycomb catalyst with annular pores.

[0072] (10) The prepared molecular sieve-based honeycomb catalyst with annular pores was granulated, and the particle size was controlled to be 10-15 mesh. The catalyst was evaluated by simulating flue gas components N2, NH3, NO, O2, and H2O in small samples with a space velocity of 60,000 h⁻¹. -1 [NO] = [NH3] = 500ppm, [O2] = 5%, H2O = 5%. The NO concentrations at the inlet and outlet were measured respectively, and the denitrification efficiency of the catalyst was calculated.

[0073] Comparative Example 1

[0074] Weigh the following raw materials according to the following proportions based on their weight;

[0075] 3 parts lotus root starch, 7 parts deionized water, 5 parts FeCu-ZSM-5 molecular sieve, 5 parts natural silica-alumina mineral kaolin, and 1 part aluminum sol.

[0076] (1) Add FeCu-ZSM-5 molecular sieve, lotus root starch, natural silica-alumina mineral kaolin, and alumina sol to a mixer for dry mixing;

[0077] (2) After mixing thoroughly, add deionized water;

[0078] (3) Mix the materials for 3 hours;

[0079] (4) Knead the clay mixture from step (3) three times.

[0080] (5) Seal the mud material from step (4) with plastic wrap and place it in a dry and cool place to age for 2 days;

[0081] (6) Put the prepared clay from step (5) into a molding machine and extrude it into shape;

[0082] (7) Place the formed honeycomb in a 100℃ oven to remove residual water until constant weight;

[0083] (8) The honeycomb monolithic catalyst dried in step (8) is placed in a muffle furnace for calcination. The calcination curve is as follows: the temperature is raised from room temperature, controlled to increase by 0.5°C per minute, raised to 300°C and held for 2 hours, and then raised to 600°C and held for 10 hours to obtain the catalyst.

[0084] (9) Granulate the prepared catalyst, controlling the particle size to 10-15 mesh, and evaluate the catalyst by simulating flue gas components N2, NH3, NO, O2, and H2O in small samples at a space velocity of 60,000 h⁻¹.-1 [NO] = [NH3] = 500ppm, [O2] = 5%, H2O = 5%. The NO concentrations at the inlet and outlet were measured respectively, and the denitrification efficiency of the catalyst was calculated.

[0085] Figure 1 The annular pore distribution of the catalyst prepared in Example 1 before calcination is shown below. Figure 1 As can be seen, after roasting, the external organic matter is removed, and an annular pore structure appears.

[0086] The evaluation results of the denitration reaction of the catalysts prepared in Examples 1-3 and Comparative Example 1 are shown in Table 1.

[0087] Table 1. Activity temperature window of the catalyst

[0088] Testing items <![CDATA[NO conversion rate of molecular sieve catalyst x ≥ 90%]]> Example 1 345～595℃ Example 2 351～598℃ Example 3 348～599℃ Comparative Example 1 377～546℃

[0089] Through experimental verification, this invention employs flocculation and sedimentation coating technology to introduce molecular sieve catalysts in the form of composite slurry. This process protects the molecular sieve catalyst during molding, while calcination removes organic matter, creating annular pores that effectively reduce diffusion limitations, improve activity accessibility, and provide a wide activity temperature window. In practical applications, this invention effectively protects the molecular sieve catalyst as the active component, meets high-temperature activity requirements, embodies green and environmentally friendly principles, and possesses high application value.

[0090] Finally, it is necessary to state that the above embodiments are only used to further illustrate the technical solution of the present invention in detail, and should not be construed as limiting the scope of protection of the present invention. Any non-essential improvements and adjustments made by those skilled in the art based on the above content of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A method for preparing a molecular sieve-based honeycomb catalyst with annular pores, characterized in that, Includes the following steps: (1) Mix starch aqueous solution, alcohol solution and acid, and then heat to depolymerize and crosslink, to obtain a mixed solution; (2) Add molecular sieve catalyst to the above mixed solution, and obtain composite slurry after flocculation and coating; (2) Natural silica-alumina minerals and inorganic binders are premixed and then added to the above composite slurry. After kneading, slurrying, aging, extrusion molding, drying and calcination, a molecular sieve-based honeycomb catalyst with annular pores is obtained.

2. The method for preparing a molecular sieve-based honeycomb catalyst with annular pores according to claim 1, characterized in that, The starch in the starch aqueous solution mentioned in step (1) is one or more of the following: corn starch, lotus root starch, potato starch, mung bean starch, kudzu root starch, sweet potato starch, wheat starch, and pea starch. The mass fraction of starch in the starch aqueous solution is 0.1% to 70.0%. The alcohol in the alcohol solution mentioned in step (1) is one or more of ethanol, polyethylene glycol, ethylene glycol, and polyethylene glycol, and the mass fraction of the alcohol in the alcohol solution is 0.1% to 90.0%. The acid mentioned in step (1) is one or more of the following: nitric acid, sulfuric acid, hydrochloric acid, fruit acid, acetic acid, boric acid, carbonic acid, phosphoric acid, citric acid, tartaric acid, malic acid, oxalic acid, and lactic acid.

3. The method for preparing a molecular sieve-based honeycomb catalyst with annular pores according to claim 1, characterized in that, The method for preparing the mixed solution in step (1) is as follows: Mix the starch aqueous solution and alcohol solution at a mass ratio of 1:0.3~10 until homogeneous, add acid to control the pH to 1~3, and maintain the pH at 80~110. o C. Stir and heat to depolymerize for 0.5~12 h.

4. The method for preparing a molecular sieve-based honeycomb catalyst with annular pores according to claim 1, characterized in that, The molecular sieve catalyst mentioned in step (2) is one or more of ZSM-5 molecular sieve, SSZ-39 molecular sieve, SSZ-13 molecular sieve, SAPO-11 molecular sieve, ZSM-35 molecular sieve, SAPO-34 molecular sieve, SAPO-47 molecular sieve, Y-type molecular sieve, Beta molecular sieve, KFI type molecular sieve, and mordenite, and the molar ratio of silica to alumina in the molecular sieve is 2~300:1; the metal element contained in the molecular sieve catalyst is one or more of iron, copper, manganese, cerium, lanthanum, rhodium, ruthenium, palladium, and osmium, and the content of the metal element is 0.1~10.0 wt%.

5. The method for preparing a molecular sieve-based honeycomb catalyst with annular pores according to claim 1, characterized in that, The composite slurry preparation process in step (2) is as follows: under continuous stirring, a molecular sieve catalyst is added to the mixed solution, with the molecular sieve catalyst having a mass ratio of 0.5~70.0 wt%, and the viscosity of the composite slurry is controlled to be 1×10⁻⁶. 2 ~1×10 5 Pa·s.

6. The method for preparing a molecular sieve-based honeycomb catalyst with annular pores according to claim 1, characterized in that, The natural silica-alumina minerals mentioned in step (3) are one or more of the following: pyrophyllite, kaolinite, palygorskite, jadeite, beryl, muscovite, serpentine, nepheline, illite, palygorskite, feldspar, spodumene, diatomite, talc, sepiolite, perlite, phlogopite, vermiculite, leucite, enstatite, diopside, amphibole, olivine, montmorillonite, kaolinite, diatomite, and attapulgite. The inorganic binder mentioned in step (3) is one or more of silica sol, water glass, boehmite, or alumina sol.

7. The method for preparing a molecular sieve-based honeycomb catalyst with annular pores according to claim 1, characterized in that, The mass ratio of each additive is: composite slurry: natural silica-alumina minerals: inorganic binder = 1~50: 1~80: 0.1~10.

8. A method for preparing a molecular sieve-based honeycomb catalyst with annular pores according to claim 1, characterized in that, The pre-mixing time in step (3) is 30-120 min, followed by kneading and mixing for 30-120 min; the number of kneading cycles is 2-5; the aging time is 1-10 days; the extrusion molding is a twin-screw extrusion or hydraulic extrusion; and the drying process involves drying the extruded material at 80-110°C. o C. Dry at a constant temperature to remove moisture until constant weight.

9. A method for preparing a molecular sieve-based honeycomb catalyst with annular pores according to claim 1, characterized in that, The calcination method described in step (3) is as follows: heating rate 0.5~2 o C / min, from room temperature to 180~400 o Hold at 550-800°C for 2-5 hours, then increase the temperature to 550-800°C. o C, calcined for 6~12 h.

10. The application of the molecular sieve-based honeycomb catalyst with annular pores obtained by the preparation method according to any one of claims 1 to 9 in the NH3-SCR reaction.

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