Preparation method and application of a molecular sieve-based honeycomb denitration catalyst taking FCC waste catalyst as carrier

Abstract

The application discloses a preparation method of a molecular sieve-based honeycomb denitration catalyst taking FCC waste catalyst as a carrier and application thereof. 1) The FCC waste catalyst is calcined to remove organic matters, crushed, and then immersed in acid solution to be etched, and after filtration, drying, calcination and crushing, pretreated FCC waste catalyst powder is obtained; 2) the powder, a molecular sieve-based catalyst, a structure manufacturing agent, an organic binder, an inorganic binder, a pore-forming agent, a extrusion aid, glass fiber, an acid solution, a humectant and water are subjected to dry mixing, kneading, mud refining, aging, extrusion molding, pre-drying, structural water solution, drying and calcination procedures to obtain the product. The application takes the FCC waste catalyst as the main carrier of the honeycomb denitration catalyst, realizes comprehensive utilization of resources, adjusts the structure of the honeycomb carrier, realizes the connection of the inner wall of the honeycomb by using the structure manufacturing agent, and realizes the organic matter coating structure of the outer layer of the molecular sieve catalyst by adjusting the feeding sequence, and increases the activity accessibility of the integral catalyst.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of nitrogen oxide removal, and particularly relates to a preparation method of a molecular sieve-based honeycomb denitration catalyst taking FCC waste catalyst as a carrier and application thereof. BACKGROUND

[0002] Nitrogen oxide (NO x ) is one of the main atmospheric pollutants, which has great harm to human body, environment and even social economy. Among numerous denitration technologies, the selective catalytic reduction (NH3-SCR) technology taking ammonia as a reducing agent is the most mature and widely used. The vanadium element in the traditional vanadium-tungsten-titanium catalyst has biological toxicity and environmental harmfulness, while the molecular sieve catalyst has special pore structure, adjustable acidity and excellent hydrothermal stability, and has good performance in the removal of nitrogen oxide, and thus can be used as a core catalyst. On the other hand, TiO2 as a main catalytic carrier is expensive, and it is particularly important to seek a catalytic carrier that can be adapted to the molecular sieve catalyst.

[0003] FCC catalyst is widely used in oil processing, and about 200,000 tons of FCC catalyst is produced in China every year, of which about 150,000 tons of solid waste is discharged, and a lot of resources are consumed to treat the solid waste. The FCC waste catalyst mainly contains Y-type molecular sieve, kaolin and related binders, and contains a certain amount of rare earth elements such as La and Ce and inorganic elements such as Ni, V and Fe. The kaolin in the catalyst has a certain promoting effect in the catalyst forming, and in addition, some elements can help to remove nitrogen oxide, so the FCC waste catalyst can be processed and used as a honeycomb monolithic denitration catalyst carrier.

[0004] Chinese patent application CN 115672262 A combines FCC spent catalyst with clay to form an adsorbent, determining the possibility of further utilization of the pretreated FCC spent catalyst. Chinese patent application CN 109985670 A combines waste honeycomb TiO2 and FCC spent catalyst to prepare a denitration catalyst carrier, which does not contain catalytically active components and does not consider the adjustment of the structure and pore of the carrier. Chinese patent application CN 116689018 A uses FCC spent catalyst as the main component to prepare a carrier, and grows CeO2 and La2O3 in situ after acid treatment. This technology improves the roughness of the surface after forming, promotes surface growth, and to some extent improves the catalytic performance. Chinese patent application CN 109482222B successfully prepares a honeycomb denitration catalyst through pretreatment technology. This technology uses V and other metal oxides as the main active component, and still has certain biological toxicity. Although the recycling and processing technology of FCC spent catalyst has been reported, there is still a certain gap in the extrusion technology combined with molecular sieve catalyst. The main difficulty is how to use FCC spent catalyst as a carrier without reducing the catalytic activity of the molecular sieve and achieving smooth forming. SUMMARY

[0005] The purpose of the present application is to provide a preparation method of a molecular sieve-based honeycomb denitration catalyst with FCC spent catalyst as a carrier and its application. The present application utilizes FCC spent catalyst as a resource, processes solid waste while preparing a honeycomb monolithic catalyst, and adjusts the structure of the catalyst to increase the accessibility of the catalyst activity.

[0006] To achieve the above purpose, the present application adopts the following technical solutions:

[0007] A preparation method of a molecular sieve-based honeycomb denitration catalyst with FCC spent catalyst as a carrier, comprising the following steps:

[0008] (1) The FCC spent catalyst is calcined to remove organic matter, crushed, and then immersed in acid solution. After filtration, drying, calcination, and crushing, a pretreated FCC spent catalyst powder is obtained;

[0009] (2) The pretreated FCC spent catalyst powder, molecular sieve-based catalyst, structure manufacturing agent, organic binder, inorganic binder, pore-forming agent, extrusion aid, glass fiber, acid solution, humectant, and water are subjected to dry mixing, kneading, mud refining, aging, extrusion molding, pre-drying, structural water solution, drying, and calcination processes to obtain a molecular sieve-based honeycomb denitration catalyst with FCC spent catalyst as a carrier, which can be applied to NH3-SCR reaction.

[0010] In step (1), the calcination temperature is 500-600℃, the calcination time is 4-8h, the pH of the acid solution is 1-4, and the particle size of the pretreated FCC spent catalyst powder is not less than 200 mesh.

[0011] The molecular sieve-based catalyst contains one or more of ZSM-5 molecular sieve, ZSM-35 molecular sieve, SSZ-13 molecular sieve, SSZ-39 molecular sieve, SAPO-11 molecular sieve, SAPO-34 molecular sieve, SAPO-47 molecular sieve, Y-type molecular sieve, Beta molecular sieve, KFI-type molecular sieve, mordenite (MOR), and the molar ratio of silica to alumina of the molecular sieve is 2-300:1. The molecular sieve-based catalyst contains one or more of iron, copper, manganese, cerium, lanthanum, rhodium, ruthenium, palladium, and osmium, and the content of the metal element is 0.1-10.0wt%.

[0012] The organic binder is one or more of sodium carboxymethyl cellulose, sodium hydroxypropyl cellulose, polyethylene glycol, polyethylene oxide, sodium polyacrylate, and phenolic resin.

[0013] The extrusion aid is one or more of flour, starch, sesbania powder, ethanolamine, or sodium stearate.

[0014] The glass fiber has a main length distribution of 1.0-10.0mm.

[0015] The structure manufacturing agent is a water-soluble polymer fiber, including one or more of water-soluble polyvinyl alcohol fiber, water-soluble seaweed fiber, and water-soluble carboxymethyl cellulose fiber. If it is in a bundle shape, the length requirement is 0.2mm-3.0mm, and the diameter requirement is 10μm-100μm, and the length is adjusted according to the thickness of the honeycomb wall to achieve the purpose of directly penetrating the inner wall; if it is in a spherical shape, the mesh number is required to be not less than 200 mesh.

[0016] The pore-forming agent is a plant fiber particle, including one or more of straw, rice husk, sawdust, wood chips, and bamboo chips, and the particle size is not less than 200 mesh.

[0017] The inorganic binder is one or more of silica sol, water glass, pseudo-boehmite, or aluminum sol.

[0018] The acid solution is an organic acid solution and an inorganic acid solution, the organic acid includes one or more of citric acid, tartaric acid, malic acid, oxalic acid, and lactic acid; the inorganic acid includes one or more of hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, and boric acid. The concentration of the organic acid solution and the inorganic acid aqueous solution is 5-20wt%.

[0019] The humectant is one or more of glycerol, tung oil, and peanut oil.

[0020] The water is one or more of deionized water, pure water, mineral water.

[0021] The mass ratio of each raw material is: FCC waste catalyst: molecular sieve: organic binder: extrusion aid: glass fiber: structure manufacturing agent: pore-forming agent: inorganic binder: organic acid: inorganic acid: humectant: water = 45-100: 1-35: 1-5: 1-8: 1-5: 10-50: 1-20: 3-8: 1-5: 1-5: 3-10: 10-25.

[0022] In step (1), the dry mixing and kneading step is: uniformly mixing the molecular sieve-based catalyst with the pore-forming agent to obtain powder A; uniformly mixing the pretreated FCC waste catalyst powder with the structure manufacturing agent and the glass fiber to obtain powder B; then uniformly mixing powder A, powder B, the extrusion aid and the organic binder, and then adding the inorganic binder, the inorganic acid, the organic acid, the humectant and water for bonding.

[0023] The number of times of kneading is 2-3 times; the aging time is 1-10 days; the extrusion molding is double-screw extrusion, which is performed in cooperation with molds of different shapes, and the wall thickness adjustment range is 0.5-3.0 mm; the pre-drying is pre-removal of 5 wt% moisture of the material; the drying method is a temperature and humidity synergistic cross control method, that is, the humidity and temperature curves are controlled to cross and synergistically dry and remove water; and the calcination method is a low-rate platform temperature rising method, and the calcination is performed in a muffle furnace in a sealed manner.

[0024] The structured water soaking is soaking the pre-dried material in water at 20-90℃ for 0.5-2.0h, and then rinsing 2-3 times with water at 20-90℃ (the temperature of the water is set according to the dissolution temperature of the structure manufacturing agent);

[0025] Further, the drying method is a temperature and humidity synergistic cross control method, the temperature is controlled to be 25-100℃, and the humidity is controlled to be 5%-95%. Preferably, in the drying process, the temperature is first controlled to be 25℃, and the humidity is controlled to be 80%; then the temperature is controlled to be 40℃, and the humidity is controlled to be 60%; then the temperature is controlled to be 60℃, and the humidity is controlled to be 40%; and then the temperature is controlled to be 80℃, and the humidity is controlled to be 10%. This method is beneficial to control the drying rate and reduce cracking.

[0026] Further, the calcination method is: the initial temperature is greater than 80℃, then the temperature is raised at a rate of 0.5-2℃ / min, the temperature is raised to 180-400℃, and the glue is removed for 2-3h, and then the temperature is continuously raised to 550-800℃ for calcination for 6-12h.

[0027] Compared with the prior art, the application has the following advantages:

[0028] 1. The application utilizes FCC waste catalyst as a carrier, molecular sieve catalyst as an active component, adopts extrusion molding technology, and uses water-soluble structure manufacturing agent to adjust the structure of the prepared catalyst and increase the accessibility of activity.

[0029] 2. In the powder mixing step, the pore-forming agent is mixed with the molecular sieve base catalyst in advance, the structure manufacturing agent is pre-mixed with the FCC waste catalyst carrier, and the structure of the pore is fully adjusted. By adjusting the feeding sequence, the outer coating of the molecular sieve catalyst is realized, the activity accessibility of the inner molecular sieve catalyst is increased, and the pore blocking phenomenon of the molecular sieve catalyst caused by the addition of the binder is effectively avoided.

[0030] 3. The application can realize effective recycling of FCC waste catalyst, reduce the cost of solid waste treatment and the cost of denitration catalyst preparation, complete high-value recycling, and realize economic production of molecular sieve base honeycomb monolithic denitration catalyst, which has good industrial application prospect. DETAILED DESCRIPTION

[0031] The application will be further described below in combination with specific examples, which are intended to illustrate the embodiments and characteristics of the application in detail and cannot be understood as any limitation of the application.

[0032] The FeCu-ZSM-5, FeCu-SSZ-13, Fe-MOR and Fe-ZSM-5 molecular sieves in the examples are high-performance denitration molecular sieve catalysts synthesized in one pot in situ, which belong to metal-modified molecular sieve catalysts. The addition of Fe can ensure the catalytic activity at high temperature, and the introduction of Cu is beneficial to broaden the temperature window at low temperature.

[0033] Example 1

[0034] A preparation method of a molecular sieve base honeycomb denitration catalyst using FCC waste catalyst as a carrier, comprising the following steps:

[0035] According to mass parts, the following components are weighed: FCC waste catalyst 45 parts, FeCu-SSZ-13 molecular sieve 40 parts, sodium carboxymethyl cellulose 2 parts, sesbania powder 6 parts, glass fiber (aspect ratio 2-4:1) 1 part, water-soluble polyvinyl alcohol bundle fiber 20 parts, wood chips 10 parts, silica sol 8 parts, lactic acid 1 part, nitric acid 1 part, glycerol 9 parts, and deionized water 25 parts.

[0036] 1) Take the FCC waste catalyst, calcine at 600 DEG C for 8h to remove organic matter, then crush it to a particle size not less than 200 mesh, add it to a dilute sulfuric acid solution (pH = 2) and soak and stir for 5h, filter the filter cake, dry at 90 DEG C, and calcine at 600 DEG C for 5h, crush it to a particle size not less than 200 mesh, and obtain the pretreated FCC waste catalyst powder;

[0037] 2) FeCu-SSZ-13 molecular sieve, sawdust are added into the mixer and mixed uniformly to obtain powder A;

[0038] The pretreated FCC spent catalyst powder, water-soluble polyvinyl alcohol fiber, and glass fiber are added into the mixer and mixed uniformly to obtain powder B;

[0039] The powder A, powder B, and the sesbania powder, sodium carboxymethyl cellulose are added into the mixer and mixed uniformly to obtain uniform dry material;

[0040] Then, silica sol, nitric acid, lactic acid, glycerol, and deionized water are added for kneading;

[0041] 3) The kneaded mud is repeatedly kneaded for 3 times;

[0042] 4) The mud is sealed with a preservative film and placed in a dry and cool place for aging for 24 h;

[0043] 5) The kneaded mud is placed into a molding machine for extrusion molding;

[0044] 6) The molded honeycomb is pre-dried to remove 5 wt% of the total mass of water, and the water-soluble polyvinyl alcohol fiber is removed by soaking in 100℃ boiling water for 10 hours, and then taken out and rinsed with 60℃ water for 3 times.

[0045] 7) The rinsed material is dried, and the drying curve is as follows: temperature 30℃, humidity 70%, drying for 10 h; temperature 50℃, humidity 60%, drying for 5 h; temperature 70℃, humidity 30%, drying for 3 h; finally, transferred to a general oven at 100℃ for 3 h.

[0046] 8) The dried material is placed into a muffle furnace for calcination, and the calcination curve is as follows: 100℃ for starting temperature, control the temperature rise of 0.5℃ per minute, 200℃ for 3 h for glue removal, continue to rise to 400℃ for 2 h, and then rise to 600℃ for 10 h to obtain the molecular sieve-based honeycomb denitration catalyst.

[0047] The prepared molecular sieve-based honeycomb denitration catalyst is placed into a bulk catalyst evaluation device, and the components of the simulated flue gas N2, NH3, H2O, NO, and O2 are evaluated for small samples, and the space velocity is maintained at 5000h -1 , [NO] = [NH3] = 500ppm, [O2] = 5%, H2O = 5%, the NO concentration of the inlet and outlet is detected respectively, and the denitration efficiency of the catalyst is calculated. The results are shown in Table 1.

[0048] Example 2

[0049] A preparation method of a molecular sieve-based honeycomb denitration catalyst with FCC spent catalyst as the carrier, comprising the following steps:

[0050] The following components are weighed according to mass parts: FCC spent catalyst 25 parts, FeCu-ZSM-5 molecular sieve 60 parts, sodium carboxymethyl cellulose 2 parts, sesbania powder 7 parts, glass fiber (aspect ratio 2-4:1) 1 part, water-soluble polyvinyl alcohol fiber 25 parts, bamboo powder 10 parts, pseudoboehmite 5 parts, lactic acid 1 part, nitric acid 1 part, glycerol 9 parts, and deionized water 40 parts.

[0051] 1) Take the FCC spent catalyst, calcine at 600°C for 7h to remove organic matter, then crush to a particle size of not less than 200 mesh, add to a dilute sulfuric acid solution (pH = 2) and soak and stir for 5h, filter the cake, dry at 80°C, and calcine at 600°C for 5h, then crush to a particle size of not less than 200 mesh to obtain the pretreated FCC spent catalyst.

[0052] 2) Mix the FeCu-ZSM-5 molecular sieve and bamboo powder in a mixer to obtain powder A;

[0053] Mix the pretreated FCC spent catalyst, water-soluble polyvinyl alcohol fiber, and glass fiber in a mixer to obtain powder B;

[0054] Mix powder A, powder B, sesbania powder, and sodium carboxymethyl cellulose in a mixer to obtain uniform dry material;

[0055] Then add silica sol, nitric acid, lactic acid, glycerol, and deionized water for kneading;

[0056] 3) Repeat the kneaded mud 2-3 times;

[0057] 4) Seal the mud with plastic wrap and store in a dry and cool place for 40h;

[0058] 5) Put the well-kneaded mud into a molding machine for extrusion molding;

[0059] 6) Dry the molded honeycomb and remove 5wt% of the total mass of water, then put it into 100°C boiling water to remove the water-soluble polyvinyl alcohol fiber, soak for 10 hours, then take it out and rinse with 60°C water 3 times.

[0060] 7) Dry the material, with a drying curve of temperature 30°C, humidity 70%, drying for 10h; temperature 50°C, humidity 60%, drying for 5h; temperature 70°C, humidity 30%, drying for 2h; finally transfer to a general oven at 100°C for 2h.

[0061] 8) Put the dried material into the muffle furnace for calcination, the firing curve is as follows: start to raise the temperature at 100℃, control the temperature to rise at 0.5℃ per minute, remove the gum at 200℃ for 3h, continue to raise the temperature to 400℃ for 2h, then raise the temperature to 600℃ for 8h, to obtain the molecular sieve based honeycomb denitration catalyst.

[0062] Put the prepared molecular sieve based honeycomb denitration catalyst into the whole catalyst evaluation device, simulate the flue gas components N2, NH3, H2O, NO, O2 for small sample evaluation, maintain the space velocity at 5000h-1, [NO] = [NH3] = 500ppm, [O2] = 5%, H2O = 5%, respectively detect the NO concentration of the inlet and outlet, and calculate the denitration efficiency of the catalyst. The results are shown in Table 1. -1

[0063] Example 3

[0064] A preparation method of a molecular sieve based honeycomb denitration catalyst with FCC waste catalyst as the carrier, comprising the following steps:

[0065] According to the mass fraction, the following components are weighed: FCC waste catalyst 55 parts, Fe-MOR molecular sieve 30 parts, sodium carboxymethyl cellulose 6 parts, sesbania powder 9 parts, glass fiber (aspect ratio 2-4:1) 1 part, water-soluble polyvinyl alcohol fiber 25 parts, straw 5 parts, pseudo-boehmite 5 parts, malic acid 1 part, nitric acid 4 parts, glycerol 7 parts, and deionized water 17 parts.

[0066] 1) The FCC waste catalyst is calcined at 600℃ for 8h to remove organic matter, and then it is crushed to a particle size of not less than 200 mesh. It is soaked and stirred in a dilute sulfuric acid solution (pH = 3) for 5h, the filter cake is dried at 80℃, and calcined at 600℃ for 5h, and then crushed to a particle size of not less than 200 mesh.

[0067] 2) The Fe-MOR molecular sieve and straw are mixed uniformly in a mixing machine to obtain powder A;

[0068] The pretreated FCC waste catalyst, water-soluble polyvinyl alcohol fiber, and glass fiber are mixed uniformly in a mixing machine to obtain powder B;

[0069] The powder A, powder B, and sesbania powder, pseudo-boehmite, and sodium carboxymethyl cellulose are mixed uniformly in a mixing machine to obtain uniform dry material;

[0070] Then malic acid, nitric acid, glycerol, and deionized water are added for kneading;

[0071] 3) The kneaded mud is repeatedly kneaded for 2-3 times;

[0072] 4) The mud is sealed with plastic wrap and placed in a dry and cool place for aging for 24h; ​

[0073] 5) Put the prepared mud into the molding machine to extrude into shape;

[0074] 6) After the honeycomb is shaped, it is pre-dried to remove 5wt% water, then put into 60℃ water to remove water-soluble polyvinyl alcohol fibers, soaked for 10 hours, then taken out and rinsed with 60℃ water for 3 times.

[0075] 7) Dry the material, the drying curve is: temperature 30℃, humidity 80%, drying for 10h; temperature 40℃, humidity 70%, drying for 5h; temperature 70℃, humidity 30%, drying for 3h; finally transferred to a common oven at 100℃ for 3h.

[0076] 8) Put the material into a muffle furnace to calcine, the calcination curve is: start heating at 100℃, increase the temperature by 0.5℃ per minute, calcine and remove glue at 170℃ for 2h, continue to heat to 350℃ for 2h, then heat to 550℃ for 8h, to obtain a molecular sieve-based honeycomb denitration catalyst.

[0077] Put the prepared molecular sieve-based honeycomb denitration catalyst into a bulk catalyst evaluation device, simulate the components of flue gas N2, NH3, H2O, NO, O2, maintain the space velocity at 5000h -1 , [NO] = [NH3] = 500ppm, [O2] = 5%, H2O = 5%, respectively detect the NO concentration of inlet and outlet, calculate the denitration efficiency of the catalyst. The results are shown in Table 1.

[0078] Example 4

[0079] A preparation method of a molecular sieve-based honeycomb denitration catalyst with FCC waste catalyst as carrier, comprising the following steps:

[0080] According to mass parts, the following components are weighed: FCC waste catalyst 60 parts, FeCu-ZSM-5 molecular sieve 25 parts, sodium carboxymethyl cellulose 3 parts, sesbania powder 5 parts, glass fiber (aspect ratio 2-4:1) 1 part, water-soluble polyvinyl alcohol bundle fiber 25 parts, sawdust 5 parts, silica sol 4 parts, lactic acid 1 part, nitric acid 1 part, glycerol 5 parts, deionized water 14 parts.

[0081] 1) Calcine the FCC waste catalyst at 600℃ for 8h to remove organic matter, then crush it to a particle size not less than 200 mesh, soak it in a dilute sulfuric acid solution (pH = 3) for 5h with stirring, take the filter cake and dry it at 80℃, and calcine it at 600℃ for 5h, then crush it to a particle size not less than 200 mesh.

[0082] 2) Mix the FeCu-ZSM-5 molecular sieve and sawdust in a mixer to obtain powder A;

[0083] (2) Add the pretreated FCC waste catalyst, water-soluble polyvinyl alcohol fiber, and glass fiber into a mixer and mix evenly to obtain powder B;

[0084] Powder A, powder B, guar gum powder, pseudoboehmite, and sodium carboxymethyl cellulose were added to a mixer and mixed evenly to obtain a uniform dry material.

[0085] Then add silica sol, lactic acid, nitric acid, glycerin and deionized water and knead.

[0086] 3) Knead the kneaded clay repeatedly 2-3 times;

[0087] 4) Seal the clay with plastic wrap and place it in a dry, cool place to age for 48 hours;

[0088] 5) Place the prepared clay into a molding machine and extrude it into shape;

[0089] 6) After the honeycomb is formed, it is pre-dried to remove 5wt% of water and then placed in a 50℃ water bath to remove water-soluble polyvinyl alcohol bundles. After soaking for 10 hours, it is taken out and rinsed 3 times with 60℃ water.

[0090] 7) Dry the rinsed material. The drying curve is as follows: 30℃, 80% humidity, 10h; 50℃, 60% humidity, 5h; 70℃, 30% humidity, 3h; finally, transfer to an oven at 100℃ for 3h.

[0091] 8) The dried material is placed in a muffle furnace for calcination. The calcination curve is as follows: start heating at 100℃, increase the temperature by 0.5℃ per minute, calcin at 230℃ for 2 hours to remove the binder, continue heating to 420℃ for 2 hours, and then heat to 650℃ for 8 hours to obtain a molecular sieve-based honeycomb denitrification catalyst.

[0092] The prepared molecular sieve-based honeycomb denitrification catalyst was placed in an integrated catalyst evaluation device to simulate flue gas components N2, NH3, H2O, NO, and O2, while maintaining a space velocity of 5000 h⁻¹. -1 The concentrations of NO at the inlet and outlet were measured, with [NO] = [NH3] = 500 ppm, [O2] = 5%, and H2O = 5%, respectively. The denitrification efficiency of the catalyst was calculated. The results are shown in Table 1.

[0093] Table 1. Evaluation results of denitrification reaction of products in Examples 1-4

[0094]

[0095]

[0096] Through experiment demonstration, the application selects FCC waste catalyst as a carrier, realizes high value utilization of solid waste, and effectively realizes the inner wall through structure of water-soluble polymer fiber, adjusts the structure of the honeycomb body, exposes the internal embedded molecular sieve catalyst, and realizes the outer coating structure of the molecular sieve catalyst by adjusting the feeding sequence, and increases the pore structure. Compared with the traditional V-based catalyst, the application not only replaces the core catalyst, but also is more green and environmental protection in the recycling of solid waste, and is more in line with the environmental protection economy, and has practical application value.

Claims

1. A method for preparing a molecular sieve-based honeycomb denitration catalyst using FCC spent catalyst as a carrier, characterized by, It comprises the following steps: (1) the FCC spent catalyst is calcined to remove organic matter, crushed and then immersed in acid solution, filtered, dried, calcined and crushed to obtain pretreated FCC spent catalyst powder; (2) the pretreated FCC spent catalyst powder, molecular sieve-based catalyst, structure manufacturing agent, organic binder, inorganic binder, pore-forming agent, extrusion aid, glass fiber, acid solution, humectant and water are subjected to dry mixing, kneading, mud refining, aging, extrusion molding, pre-drying, structured water solution, drying and calcination processes to obtain a molecular sieve-based honeycomb denitration catalyst; The dry mixing and kneading steps are as follows: the molecular sieve-based catalyst is uniformly mixed with the pore-forming agent to obtain powder A; the pretreated FCC spent catalyst powder is uniformly mixed with the structure manufacturing agent and glass fiber to obtain powder B; then powder A, powder B, extrusion aid and organic binder are uniformly mixed, and inorganic binder, inorganic acid, organic acid, humectant and water are added for bonding; The structure manufacturing agent is a water-soluble polymer fiber, and the polymer fiber is one or more of polyvinyl alcohol fiber, seaweed fiber and carboxymethyl cellulose fiber; the pore-forming agent is plant fiber particles; and the humectant is one or more of glycerol, tung oil and peanut oil. The mass ratio of each raw material is as follows: FCC spent catalyst: molecular sieve: organic binder: extrusion aid: glass fiber: structure manufacturing agent: pore-forming agent: inorganic binder: organic acid: inorganic acid: humectant: water = 45-100: 1-35: 1-5: 1-8: 1-5: 10-50: 1-20: 3-8: 1-5: 1-5: 3-10: 10-25.

2. The method for preparing a molecular sieve-based honeycomb denitration catalyst taking FCC spent catalyst as a carrier according to claim 1, characterized in that, In step (1), the calcination temperature is 500-600 o C, the calcination time is 4-8 h, the pH of the acid solution is 1-4, and the particle size of the pretreated FCC spent catalyst powder is not less than 200 mesh.

3. The method for preparing a molecular sieve-based honeycomb denitration catalyst taking FCC spent catalyst as a carrier according to claim 1, characterized in that, The molecular sieve-based catalyst contains one or more of ZSM-5 molecular sieve, ZSM-35 molecular sieve, SSZ-13 molecular sieve, SSZ-39 molecular sieve, SAPO-11 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 silicon dioxide to aluminum oxide of the molecular sieve is 2-300:1; the molecular sieve-based catalyst contains 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%.

4. The method for preparing a FCC spent catalyst supported molecular sieve based honeycomb denitration catalyst according to claim 1, characterized in that, The organic binder is one or more of sodium carboxymethyl cellulose, sodium hydroxypropyl cellulose, polyethylene glycol, polyethylene oxide, sodium polyacrylate and phenolic resin; The extrusion aid is one or more of flour, starch, sesbania powder, ethanolamine or sodium stearate; The plant fiber is one or more of straw, rice husk, sawdust, wood chips and bamboo chips; The inorganic binder is one or more of silica sol, water glass, pseudo-boehmite and aluminum sol; The acid solution is an organic acid solution and an inorganic acid solution, and the organic acid is one or more of citric acid, tartaric acid, malic acid, oxalic acid and lactic acid; and the inorganic acid is one or more of hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid and boric acid.

5. The method for preparing a molecular sieve-based honeycomb denitration catalyst taking FCC spent catalyst as a carrier according to claim 1, characterized in that, The structured water solution is to soak the pre-dried material in 20~90 o C water for 0.5~2.0 h, and then rinse 2~3 times with 20~90 o C water.

6. The method for preparing a molecular sieve-based honeycomb denitration catalyst taking FCC spent catalyst as a carrier according to claim 1, characterized in that, The drying method is temperature and humidity coordinated cross control, the temperature control is 25~100 o C, and the humidity control is 5%~95%. The calcination is carried out at a starting temperature greater than 80 o C, then heated at a rate of 0.5-2 o C / min, and the temperature is raised to 180-400 o C for 2-3 h, and then the temperature is further raised to 550-800 o C for 6-12 h.

7. Use of the molecular sieve-based honeycomb denitration catalyst prepared according to the preparation method of any one of claims 1-6 in an NH3-SCR reaction.

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