Ultralow-temperature flue gas denitration forming catalyst based on 3D printing and preparation method thereof

Abstract

The invention discloses an ultralow-temperature flue gas denitration forming catalyst based on 3D printing and a preparation method thereof. The preparation method comprises the following steps: S1, preparing a metal oxide precursor; s2, preparing a mixed slurry based on the metal oxide precursor, an inorganic binder, an organic binder, an auxiliary agent and a peptizing agent; s3, the mixed slurry is printed and formed through a 3D printing direct writing forming technology, and a printed blank is obtained; and S4, drying and calcining the printed blank to obtain the integral granular catalyst. According to the preparation method of the ultra-low temperature flue gas denitration forming catalyst based on 3D printing, a catalyst material is printed into a particle forming catalyst through a 3D printing technology, and uniform distribution of active components can be ensured, so that the catalytic performance and stability of the catalyst can be improved; meanwhile, the granular catalyst has extremely high stability, so that the catalyst can adapt to various reaction conditions and process requirements, and the applicability of the catalyst can be improved.

Description

Technical Field

[0001] The present invention relates to the field of catalyst technology, and in particular to a 3D-printed ultra-low-temperature flue gas denitration molded catalyst and a preparation method thereof. Background Art

[0002] Nitrogen oxides (NO x As one of the major atmospheric pollutants, NOx poses a serious threat to the ecological environment and human health. Selective catalytic reduction (SCR) technology, with its high efficiency and maturity, has become the primary choice for denitrification. However, conventional SCR catalysts rely on ceramic or metal supports (such as cordierite) and are manufactured using an extrusion process to form a honeycomb structure. However, these honeycomb catalysts have structural limitations, poor stability, and high production costs. Summary of the Invention

[0003] The present invention aims to address at least one of the technical problems existing in the prior art. To this end, the present invention proposes a method for preparing a 3D-printed ultra-low-temperature flue gas denitrification catalyst. The method can produce a granular catalyst that exhibits excellent stability and is widely applicable to various reactors.

[0004] The present invention also proposes a 3D-printed ultra-low temperature flue gas denitrification molded catalyst.

[0005] The present invention also provides a reactor having the catalyst.

[0006] According to the first aspect of the present invention, the preparation method of the ultra-low temperature flue gas denitrification molded catalyst based on 3D printing includes: step S1, preparing a metal oxide precursor; step S2, preparing a mixed slurry based on the metal oxide precursor, an inorganic binder, an organic binder, an additive and a peptizing agent; step S3, printing the mixed slurry by 3D printing direct writing technology to obtain a printed embryo; step S4, drying and calcining the printed embryo to obtain a catalyst.

[0007] According to the preparation method of the ultra-low temperature flue gas denitrification formed catalyst based on 3D printing of the present invention, the catalyst material is printed into a granular formed catalyst through 3D printing technology, which can ensure the uniform distribution of the active components, thereby improving the catalytic performance and stability of the catalyst; at the same time, the granular catalyst has extremely high stability, not only can it remain stable under high-speed airflow blowing, but it can also resist external force impact and is not easily broken, so that the catalyst can adapt to a variety of reaction conditions and process requirements, thereby improving the applicability of the catalyst; in addition, the use of 3D printing direct writing molding technology to prepare the catalyst can not only provide unprecedented flexibility in the manufacture of complex structures and customized products, but also significantly shorten the R&D cycle and reduce production costs.

[0008] According to some embodiments of the present invention, the mixed slurry includes, in parts by weight: metal oxide precursor: 70-90 parts; inorganic binder: 2-5 parts; organic binder: 5-15 parts; auxiliary agent: 2-5 parts; peptizer: 1-5 parts.

[0009] According to some embodiments of the present invention, the inorganic binder is one or more of aluminum sol, silica sol, sodium silicate, halloysite nanotubes, bentonite and kaolin; and / or, the organic binder is one or more of polyvinyl alcohol, polyethylene glycol, polyacrylamide, carboxymethyl cellulose and starch; and / or, the auxiliary agent is one or more of sesbania powder, graphite, polytetrafluoroethylene, glycerol, glass fiber and activated carbon; and / or, the peptizing agent is one or more of oxalic acid, citric acid, acetic acid and ammonia water.

[0010] According to some embodiments of the present invention, the metal oxide precursor, the inorganic binder, the organic binder, the auxiliary agent and the peptizing agent are placed in a ball mill to prepare a mixed slurry, the ball milling speed is 200r / min-500r / min, and the ball milling time is 10min-30min.

[0011] According to some embodiments of the present invention, the drying temperature of the printed body is 50° C.-120° C., and the drying time is 2 h-8 h; the calcination temperature of the printed body is 300° C.-600° C., and the calcination time is 2 h-8 h.

[0012] According to some embodiments of the present invention, step S1 includes: step S11, preparing an alkaline solution containing an alkali metal or an alkaline earth metal; step S12, adding a metal oxide carrier to the alkaline solution and stirring and mixing to obtain a mixture; step S13, placing the mixture in a hydrothermal reactor for hydrothermal reaction to obtain a reactant; step S14, filtering and drying the reactant to obtain a metal oxide precursor.

[0013] According to some embodiments of the present invention, the alkaline solution of alkali metal or alkaline earth metal is one or more of sodium hydroxide solution, potassium hydroxide solution, rubidium hydroxide solution, cesium hydroxide solution, magnesium hydroxide solution, calcium hydroxide solution, strontium hydroxide solution, barium hydroxide solution and ammoniacal alkali metal solution; and / or the metal oxide carrier is one or more of manganese oxide, manganese dioxide, manganese trioxide, manganese trimanganese tetraoxide and manganese pentamanganese octoxide.

[0014] According to the second aspect of the present invention, the 3D printed ultra-low temperature flue gas denitration molded catalyst is prepared and molded by the preparation method according to the first aspect of the present invention.

[0015] According to the 3D-printed ultra-low temperature flue gas denitrification molded catalyst of the present invention, the catalyst is prepared and molded by the above-mentioned preparation method, which can ensure the uniform distribution of the active components of the catalyst, thereby improving the catalytic performance and stability of the catalyst; at the same time, the catalyst can also have extremely high stability, not only can it remain stable under high-speed airflow blowing, but it can also resist external force impact and is not easily broken, so that the catalyst can adapt to a variety of reaction conditions and process requirements, thereby improving the applicability of the catalyst.

[0016] According to some embodiments of the present invention, the catalyst is in the form of spherical, cylindrical, flaky or columnar particles, and / or the diameter of the catalyst is 2 mm to 9 mm, and / or the length of the catalyst is 5 mm to 10 mm.

[0017] The reactor according to the third aspect of the present invention comprises a fixed bed or a fluidized bed and the catalyst according to the second aspect, wherein the catalyst is used to be loaded in the fixed bed or the fluidized bed.

[0018] According to the reactor of the present invention, by filling the above-mentioned catalyst, the stability and reliability of the entire process can be improved. At the same time, the frequency of replacing the catalyst can be reduced, thereby reducing maintenance costs.

[0019] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a flow chart of a method for preparing a 3D printed ultra-low temperature flue gas denitration catalyst according to an embodiment of the present invention;

[0021] Figure 2 is a flow chart of preparing metal oxide according to an embodiment of the present invention;

[0022] Figure 3 This is an overall flow chart of a method for preparing a 3D printed ultra-low temperature flue gas denitration molded catalyst according to an embodiment of the present invention. DETAILED DESCRIPTION

[0023] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present invention, but are not to be construed as limiting the present invention.

[0024] Reference below Figure 1-Figure 3 The present invention describes a method for preparing a 3D printed ultra-low temperature flue gas denitration molded catalyst according to an embodiment of the first aspect of the present invention.

[0025] like Figure 1 and Figure 3 As shown, according to an embodiment of the present invention, a method for preparing a 3D-printed ultra-low temperature flue gas denitration catalyst comprises:

[0026] Step S1, preparing a metal oxide precursor; it should be noted that the metal oxide precursor is a modified metal oxide, which has good low-temperature activity and oxidation performance.

[0027] Step S2, preparing a mixed slurry based on a metal oxide precursor, an inorganic binder, an organic binder, an additive and a peptizing agent; it should be noted that the inorganic binder is mainly used to ensure the structural stability of the catalyst; the organic binder is mainly used to improve the plasticity and wear resistance of the slurry during the molding process and the wear resistance of the catalyst after molding; the additive is mainly used to reduce friction and improve the fluidity of the embryo extrusion; the peptizing agent is mainly used to adjust the pH of the mixed slurry, thereby providing a suitable chemical environment for the organic binder, so that it can better exert its bonding effect and molding performance.

[0028] In step S3, the mixed slurry is printed and formed by 3D printing direct writing technology to obtain a printed embryo. It should be noted that 3D printing direct writing technology is an additive manufacturing process based on the extrusion principle, which constructs a three-dimensional structure by precisely controlling the extrusion of materials.

[0029] Step S4 involves drying and calcining the printed body to obtain a monolithic granular catalyst. It should be noted that during the 3D printing process, the drying step primarily removes solvent from the printed part, thereby facilitating the catalyst's ultimate structural stability. It also serves as a preliminary solidification step, increasing the physical strength of the printed body and facilitating transfer to the calcination site. Calcination, a high-temperature process, primarily removes organic binders or other impurities from the 3D-printed object. Calcination also densifies the material structure, enhancing its hardness, wear resistance, and other mechanical properties.

[0030] In the existing technology, traditional SCR catalysts mainly rely on ceramic or metal carriers (such as cordierite) and are prepared into honeycomb structures through an extrusion molding process. However, this form of molding has problems such as structural limitations, poor low-temperature activity and high preparation costs.

[0031] In this application, a 3D printing direct writing technology is used to print a printed body, and then the printed body is dried and calcined in an air atmosphere to obtain a whole granular catalyst. Among them, 3D printing technology, as an emerging manufacturing process, can quickly produce complex three-dimensional entities by adding materials layer by layer. It has significant advantages in manufacturing complex structures, customized products and rapid prototyping. Then, the use of 3D printing direct writing technology to prepare catalysts can not only provide unprecedented flexibility in manufacturing complex structures and customized products, but also significantly shorten the R&D cycle and reduce production costs. At the same time, the preparation of granular catalysts by 3D printing technology can not only achieve precise and uniform distribution of active components, but also flexibly control the microstructure and macromorphology, thereby significantly improving catalytic performance, stability and engineering adaptability. In addition, compared with traditional honeycomb denitrification catalysts, granular catalysts have no pores. Therefore, they have extremely high stability. Not only can they remain stable under high-speed airflow, but they can also resist external impact and are not easily broken.

[0032] According to the preparation method of the ultra-low temperature flue gas denitrification molded catalyst based on 3D printing according to the embodiment of the present invention, the catalyst material is printed into a granular molded catalyst through 3D printing technology, which can ensure the uniform distribution of active components, thereby improving the catalytic performance and stability of the catalyst; at the same time, the granular catalyst has extremely high stability, not only can it remain stable under high-speed airflow blowing, but it can also resist external force impact and is not easily broken, so that the catalyst can adapt to a variety of reaction conditions and process requirements, thereby improving the applicability of the catalyst; in addition, the use of 3D printing direct writing molding technology to prepare the catalyst can not only provide unprecedented flexibility in the manufacture of complex structures and customized products, but also significantly shorten the R&D cycle and reduce production costs.

[0033] According to some embodiments of the present invention, the mixed slurry includes, by weight, 70-90 parts of a metal oxide precursor; 2-5 parts of an inorganic binder; 5-15 parts of an organic binder; 2-5 parts of an auxiliary agent; and 1-5 parts of a peptizing agent. For example, for 100 parts of the mixed slurry, the metal oxide may be 90 parts, the inorganic binder may be 2 parts, the organic binder may be 5 parts, the auxiliary agent may be 2 parts, and the peptizing agent may be 1 part. In other words, by weight, the metal oxide precursor, the inorganic binder, the organic binder, the auxiliary agent, and the peptizing agent together account for 100 parts.

[0034] Among them, the metal oxide precursor is the main component of the catalyst, which is mainly used to ensure the oxidation performance and low-temperature activity of the catalyst, so that the catalyst has excellent low-temperature nitrogen oxide removal performance; the inorganic binder is mainly used to ensure the structural stability of the catalyst; the organic binder is mainly used to improve the plasticity and wear resistance of the slurry during the molding process and the wear resistance of the catalyst after molding; the auxiliary agent is mainly used to reduce friction and improve the fluidity of the embryo extrusion; the peptizing agent is mainly used to adjust the pH of the mixed slurry, thereby providing a suitable chemical environment for the organic binder, so that it can better exert its bonding effect and molding performance.

[0035] According to some embodiments of the present invention, the inorganic binder is one or more of alumina sol, silica sol, sodium silicate, halloysite nanotubes, bentonite, and kaolin. Specifically, the inorganic binder is one or more of the aforementioned adhesives, and the specific amount can be adjusted based on specific application requirements to achieve optimal results and enhance the structural stability of the final catalyst.

[0036] Specifically, alumina sol is a stable suspension of alumina particles dispersed in water or other solvents. Alumina sol exhibits excellent thermal stability and chemical inertness. In catalyst preparation, alumina sol is often used as a binder, strengthening the bonding between catalyst particles and improving the high-temperature resistance of the finished product. It also promotes the uniform distribution of active components and helps maintain the catalyst's porous structure.

[0037] Silica sol is composed of fine silicon dioxide particles and is typically transparent or translucent. It exhibits excellent weather and chemical resistance. When used as a binder, it provides excellent mechanical strength and chemical stability. Furthermore, due to its unique microporous structure, silica sol can improve the diffusion of catalysts, increase specific surface area, and thus enhance catalytic efficiency.

[0038] Sodium silicate is a common inorganic binder that dissolves readily in water, forming an alkaline solution. During heating, it dehydrates and hardens, forming a strong structure. In catalyst preparation, sodium silicate not only serves as a binder but also regulates the pH of the catalyst, affecting the state of the active components.

[0039] Halloysite nanotubes are naturally occurring nanomaterials with hollow tubular structures, typically with an inner diameter of tens of nanometers. This unique morphology gives halloysite nanotubes an extremely high aspect ratio and a large specific surface area. As a novel binder, halloysite nanotubes not only significantly enhance the mechanical strength of catalysts but also allow their internal space to accommodate more active components, thereby improving the catalyst's overall performance.

[0040] Bentonite, primarily composed of montmorillonite, possesses strong water-swelling and ion-exchange properties. It rapidly swells in water, forming a gel-like substance. In catalyst preparation, bentonite can be used as a binder and thickener to help stabilize active components. Its excellent ion-exchange properties also help regulate the pH of the catalyst surface, thereby affecting the selectivity and activity of the catalytic reaction.

[0041] Kaolin is a layered silicate mineral with a low cation exchange capacity and good thermal stability. As a binder, kaolin is primarily used to enhance the mechanical strength and thermal stability of catalysts. Kaolin can also interact with active components to modify the catalyst's surface properties and optimize its catalytic performance.

[0042] According to some embodiments of the present invention, the organic binder is one or more of polyvinyl alcohol, polyethylene glycol, polyacrylamide, carboxymethyl cellulose, and starch. Specifically, the organic binder is one or more of the above-mentioned adhesives, and the amount thereof can be adjusted according to specific application requirements to achieve the optimal effect and improve the structural stability and wear resistance of the final catalyst.

[0043] Among them, polyvinyl alcohol has the characteristics of good film-forming properties, strong adhesion, non-toxicity and environmental protection. As an organic adhesive in the catalyst preparation process, it is beneficial to improve the strength of the embryo and increase the binding force between particles. Polyethylene glycol can adjust the fluidity of the slurry. It has high plasticizing properties, which can improve the rheological properties of extrusion or printing and reduce friction; polyacrylamide has extremely strong flocculation and thickening properties, which can enhance the suspension stability of the mixed solution and prevent sedimentation; carboxymethyl cellulose has good adhesion, water retention and dispersibility, and can play a dual role of bonding and stabilization; starch is a green adhesive that can provide preliminary bonding function.

[0044] According to some embodiments of the present invention, the additive is one or more of sesbania powder, graphite, polytetrafluoroethylene, glycerol, glass fiber, and activated carbon. Specifically, the additive is one or more of the above additives, and the additive can be adjusted according to specific application requirements to achieve the best effect, thereby improving the extrusion smoothness of the mixed slurry.

[0045] Specifically, sesbania powder is a natural polymer compound, often used as a thickener and suspending agent, which can increase the viscosity of the slurry and prevent solid particles from settling; graphite has excellent lubricating properties, which helps reduce friction; PTFE is known for its extremely low friction coefficient, and adding it to the material can significantly improve its wear resistance and self-lubricating properties; glycerin is a common moisturizer, and adding it to the slurry can help retain the moisture of the material, increase flexibility and ductility; glass fiber is a commonly used reinforcing material that can greatly improve the tensile strength, flexural strength and impact toughness of composite materials; activated carbon particles can change the surface properties of the matrix material, such as reducing the surface energy, making the material surface less likely to adhere to other surfaces.

[0046] According to some embodiments of the present invention, the peptizing agent is one or more of oxalic acid, citric acid, acetic acid, and ammonia. Specifically, the peptizing agent is mainly used to adjust the pH. Thus, the peptizing agent uses one or more of the above-mentioned solvents, and can be adjusted according to specific application requirements so that the pH value of the mixed solution can meet the requirements for the organic binder to play an optimal role, thereby improving the quality of subsequent products.

[0047] Among them, oxalic acid is a strong organic acid with good complexing ability, especially for polyvalent metal ions. Therefore, using oxalic acid as a peptizing agent can help prevent agglomeration between particles, thereby improving the uniformity and stability of the slurry. At the same time, it can also effectively reduce the pH value of the slurry, making the mixed slurry suitable for application scenarios that require an acidic environment; citric acid is a weak acid. Therefore, when adjusting the pH value of the solution, citric acid can provide a buffering effect, that is, it can neutralize a certain amount of strong alkali or strong acid without causing drastic changes in the pH value, which is very important for application scenarios that require precise control of pH. At the same time, citric acid can improve the dispersion of solid particles in the slurry, reduce agglomeration, and improve the fluidity and uniformity of the slurry; acetic acid is a weak acid, suitable for fine-tuning the pH value of the slurry, without changing the environment too drastically, and helps to finely control the reaction conditions; ammonia water is a commonly used alkaline solution that can effectively increase the pH value of the slurry, which is particularly important for materials or processes that require an alkaline environment.

[0048] According to some embodiments of the present invention, a metal oxide precursor, an inorganic binder, an organic binder, an additive, and a peptizing agent are placed in a ball mill to prepare a mixed slurry at a ball mill speed of 200-500 rpm for 10-30 minutes. This facilitates more thorough mixing of the mixed slurry, thereby further improving the uniformity of the active components of the formed catalyst.

[0049] For example, the ball milling speed may be 200 r / min, 300 r / min, 400 r / min or 500 r / min, and the ball milling time may be 10 min, 20 min or 30 min.

[0050] Optionally, the water content of the mixed slurry is 10 wt%-40 wt%. For example, the water content of the mixed slurry may be 10 wt%, 20 wt%, 30 wt% or 40 wt%.

[0051] According to some embodiments of the present invention, the drying temperature of the printed body is 50°C-120°C, and the drying time is 2 hours-8 hours. This ensures that the printed body can be dried more completely, thereby ensuring the removal rate of the solvent in the printed body and further ensuring the structural stability of the final product.

[0052] For example, the drying temperature of the printed body can be 50° C., 60° C., 70° C., 80° C., 90° C., 100° C., 110° C., or 120° C.; and the drying time can be 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, or 8 h.

[0053] According to some embodiments of the present invention, the printed body is calcined at a temperature of 300°C to 600°C for 2 to 8 hours, thereby ensuring the removal rate of organic binders or other impurities in the printed body and improving the mechanical properties of the final product.

[0054] For example, the calcination temperature of the printed body can be 300° C., 400° C., 500° C., or 600° C.; and the calcination time can be 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, or 8 h.

[0055] According to some embodiments of the present invention, Figure 2-Figure 3 As shown, step S1 includes:

[0056] Step S11: preparing an alkaline solution containing an alkali metal or alkaline earth metal. Specifically, an alkaline solution of a certain concentration is prepared, for example, an alkaline solution with a concentration of 0.1 mol / L to 2 mol / L. The alkaline solution may be a sodium hydroxide solution, a magnesium hydroxide solution, a calcium hydroxide solution, or the like.

[0057] Step S12: Adding a metal oxide support to an alkaline solution and stirring to obtain a mixture. Specifically, the metal oxide support serves as a support for the catalytically active component, providing a high specific surface area and good thermal and chemical stability. The metal oxide support may be manganese oxide, manganese dioxide, or manganese trioxide. The alkaline solution primarily serves to adjust the pH, promote the hydrolysis and nucleation of metal species, and introduce alkali metal or alkaline earth metal doping to modify the surface properties of the metal oxide support.

[0058] It should be noted that when the metal oxide support is added to the alkaline solution, it needs to be stirred at a certain temperature and for a certain period of time. For example, the stirring temperature can be 40°C-90°C for 0.5-2 hours. This ensures that the metal oxide support is fully in contact with the solution, achieving uniform impregnation or adsorption.

[0059] Step S13: placing the mixture in a hydrothermal reactor to perform a hydrothermal reaction to obtain a reactant; wherein the reactant is a mixture of a metal oxide precursor and a solvent.

[0060] In step S14, the reactants are filtered and dried to obtain a metal oxide precursor. Specifically, the metal oxide precursor is a modified metal oxide support having a changed morphology and internal structure, and possessing improved microstructure and surface properties. This not only provides more active sites but also significantly improves the stability, low-temperature activity, and oxidation performance of the catalyst.

[0061] According to some embodiments of the present invention, the alkaline solution of an alkali metal or alkaline earth metal is one or more of a sodium hydroxide solution, a potassium hydroxide solution, a rubidium hydroxide solution, a cesium hydroxide solution, a magnesium hydroxide solution, a calcium hydroxide solution, a strontium hydroxide solution, a barium hydroxide solution, and an alkali ammonia solution. Specifically, the various alkaline solutions described above have different functions in preparing the metal oxide precursor. For example, a sodium hydroxide solution can promote crystallization and increase the specific surface area, while a magnesium hydroxide solution and a calcium hydroxide solution can enhance thermal stability. Therefore, the alkaline solution of an alkali metal or alkaline earth metal can be selected from one or more of the above solutions, and can be selected according to the actual requirements of the catalyst, thereby ensuring high-quality printing results.

[0062] According to some embodiments of the present invention, the metal oxide support is one or more of manganese oxide, manganese dioxide, manganese trioxide, manganese trimanganese tetraoxide, and manganese pentamanganese octoxide. It should be noted that the above metal oxides are all manganese oxides, among which manganese oxides have strong redox properties, thereby effectively improving the diffusion and contact restriction of reactants in the catalytic oxidation reaction of the catalyst, thereby improving the catalytic performance of the catalyst.

[0063] According to the second embodiment of the present invention, the 3D printed ultra-low temperature flue gas denitration molded catalyst is prepared and molded by the preparation method according to the first embodiment of the present invention.

[0064] According to the embodiment of the present invention, the ultra-low temperature flue gas denitrification molded catalyst based on 3D printing is prepared and molded by the above-mentioned preparation method, which can ensure the uniform distribution of the active components of the catalyst, thereby improving the catalytic performance and stability of the catalyst; at the same time, it can also make the catalyst exhibit extremely high stability, not only remaining stable under high-speed airflow blowing, but also resisting external force impact and not easily broken, so that the catalyst can adapt to a variety of reaction conditions and process requirements, thereby improving the applicability of the catalyst.

[0065] According to some embodiments of the present invention, the catalyst is in the form of spherical, cylindrical, flaky, or columnar particles. It is understood that the catalyst can be spherical, cylindrical, flaky, or columnar, and the specific shape can be designed according to the actual location of use, thereby enabling the catalyst to adapt to different reaction conditions and process requirements.

[0066] According to some embodiments of the present invention, the diameter of the catalyst is 2 mm to 9 mm. This ensures that the catalyst is not too large while ensuring strength and wear resistance, and thus allows the catalyst to be loaded into equipment of various specifications, thereby improving the adaptability of the catalyst.

[0067] For example, the catalyst may have a diameter of 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, or 9 mm.

[0068] According to some embodiments of the present invention, the length of the catalyst is 5 mm to 10 mm. This ensures that the catalyst is not too large while ensuring strength and wear resistance, thereby enabling the catalyst to be loaded into equipment of various specifications, thereby improving the adaptability of the catalyst.

[0069] For example, the catalyst may have a diameter of 5 mm, 6 mm, 7 mm, 8 mm, 9 mm or 10 mm.

[0070] The reactor according to the third embodiment of the present invention comprises a fixed bed reactor or a fluidized bed reactor and the catalyst according to the second embodiment, and the catalyst is used to be loaded in the fixed bed reactor or the fluidized bed reactor.

[0071] It is understood that the catalyst can be loaded in a fixed bed reactor or a fluidized bed reactor. It should be noted that the catalyst can be loaded in a fixed bed reactor or a fluidized bed reactor for ultra-low temperature flue gas denitration reaction.

[0072] Among them, a fixed bed reactor is a reactor in which the catalyst remains stationary during the reaction process; a fluidized bed reactor fluidizes the catalyst layer by passing gas or liquid through solid catalyst particles at a sufficient speed; that is, the two reactors have different working principles, and thus, the catalyst is used to be loaded in a fixed bed reactor or a fluidized bed reactor, and further, the catalyst of the embodiment of the present application can adapt to a variety of reaction conditions and process requirements.

[0073] According to the reactor of the embodiment of the present invention, by filling the above-mentioned catalyst, the stability and reliability of the entire process can be improved. At the same time, the frequency of replacing the catalyst can be reduced, thereby reducing maintenance costs.

[0074] Reference below Figure 1-Figure 3 The following describes a method for preparing a 3D printed ultra-low temperature flue gas denitration molded catalyst according to three specific embodiments of the present invention.

[0075] Example 1:

[0076] The preparation method comprises:

[0077] The carrier pentamanganese octoxide is added to a sodium hydroxide solution with a concentration of 0.5 mol / L and stirred at 80°C for 1 hour. The mixture is then placed in a hydrothermal reactor and reacted at 160°C for 12 hours. Finally, the mixture obtained after the hydrothermal reaction is filtered and dried to obtain a metal oxide precursor.

[0078] 90 parts of metal oxide precursor, 2 parts of silica sol, 5 parts of carboxymethyl cellulose, 2 parts of sesbania powder, and 1 part of ammonia water were selected, and then 20 wt% of water by mass of the mixture was added. The raw materials were mixed by ball milling to prepare a mixed slurry, wherein the ball milling speed was 400 r / min and the ball milling time was 20 min.

[0079] The slurry was printed into a cylindrical embryonic body with a diameter of 5 mm and a length of 8 mm by 3D printing direct writing technology, and then the printed embryonic body was dried at 100° C. for 6 h and finally calcined at 300° C. for 6 h to obtain a cylindrical integral particle catalyst.

[0080] Example 2:

[0081] The preparation method comprises:

[0082] The carrier manganese trioxide is added to a sodium hydroxide solution with a concentration of 1 mol / L, and the mixture is fully stirred at 80°C for 0.5 h. The mixture is then placed in a hydrothermal reactor and reacted at 180°C for 16 h. Finally, the mixture obtained after the hydrothermal reaction is filtered and dried to obtain a metal oxide precursor.

[0083] 86 parts of metal oxide precursor, 2 parts of silica sol, 8 parts of carboxymethyl cellulose, 2 parts of sesbania powder, and 2 parts of sodium hydroxide were selected, and then 30 wt% of water by mass of the mixture was added. The above raw materials were mixed by ball milling to prepare a mixed slurry, wherein the ball milling speed was 300 r / min and the ball milling time was 30 min.

[0084] The slurry was printed into a cylindrical embryonic body with a diameter of 3 mm and a length of 10 mm by 3D printing direct writing technology, and then the embryonic body was dried at 100° C. for 8 h and finally calcined at 400° C. for 6 h to obtain a cylindrical integral particle catalyst.

[0085] Example 3,

[0086] The preparation method comprises:

[0087] The carrier manganese trioxide is added to a potassium hydroxide solution with a concentration of 0.5 mol / L, and the mixture is fully stirred at 80°C for 1 hour. The mixture is then placed in a hydrothermal reactor and reacted at 160°C for 16 hours. Finally, the mixture obtained after the hydrothermal reaction is filtered and dried to obtain a metal oxide precursor.

[0088] 80 parts of metal oxide precursor, 4 parts of halloysite nanotubes, 8 parts of polyethylene glycol, 4 parts of sesbania powder, and 4 parts of ammonia water were selected, and then 30wt% of water was added to the mixture. The above raw materials were mixed by ball milling to prepare a slurry at a ball milling speed of 300r / min and a ball milling time of 30min.

[0089] The slurry was printed into a spherical embryo with a diameter of 5 mm by 3D printing direct writing technology, and then the embryo was dried at 100° C. for 8 h and finally calcined at 350° C. for 6 h to obtain a cylindrical monolithic particle catalyst.

[0090] Example 4:

[0091] The preparation method comprises:

[0092] The carrier pentamanganese octoxide is added to a barium hydroxide solution with a concentration of 0.5 mol / L, and the mixture is fully stirred at 80°C for 1 hour. The mixture is then placed in a hydrothermal reactor and reacted at 160°C for 16 hours. Finally, the mixture obtained after the hydrothermal reaction is filtered and dried to obtain a metal oxide precursor.

[0093] 88 parts of metal oxide precursor, 2 parts of kaolin, 6 parts of polyethylene glycol, 2 parts of sesbania powder, and 2 parts of ammonia water were selected, and then 15 wt% of water was added to the mixture. The above raw materials were mixed by ball milling to prepare a slurry. The ball milling speed was 400 r / min and the ball milling time was 30 min.

[0094] The slurry was printed into a cylindrical embryo with a diameter of 5 mm by 3D printing direct writing technology, and then the integral particle-type catalyst embryo was dried at 100° C. for 8 h and finally calcined at 400° C. for 6 h to obtain a cylindrical integral particle-type catalyst.

[0095] Example 5,

[0096] The preparation method comprises:

[0097] The carrier pentamanganese octoxide is added to a barium hydroxide solution with a concentration of 0.5 mol / L, and the mixture is fully stirred at 80°C for 1 hour. The mixture is then placed in a hydrothermal reactor and reacted at 160°C for 16 hours. Finally, the mixture obtained after the hydrothermal reaction is filtered and dried to obtain a metal oxide precursor.

[0098] 75 parts of metal oxide precursor, 4 parts of kaolin, 13 parts of polyethylene glycol, 4 parts of sesbania powder, and 4 parts of ammonia water were selected, and then 15 wt% of water was added to the mixture. The above raw materials were mixed by ball milling to prepare a slurry. The ball milling speed was 400 r / min and the ball milling time was 30 min.

[0099] The slurry was printed into a cylindrical embryo with a diameter of 5 mm by 3D printing direct writing technology, and then the integral particle-type catalyst embryo was dried at 100° C. for 8 h and finally calcined at 400° C. for 6 h to obtain a cylindrical integral particle-type catalyst.

[0100] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0101] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature identified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0102] In the present invention, unless otherwise expressly specified or limited, terms such as "mounted," "connected," "connect," and "fixed" should be understood broadly. For example, they may refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0103] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0104] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the claims and their equivalents.

Claims

1. A method for preparing a 3D-printed ultra-low temperature flue gas denitration catalyst, characterized in that: The preparation method comprises: Step S1, preparing a metal oxide precursor; Step S2, preparing a mixed slurry based on a metal oxide precursor, an inorganic binder, an organic binder, an additive, and a peptizing agent; Step S3, printing the mixed slurry by 3D printing direct writing technology to obtain a printed embryo; Step S4: drying and calcining the printed body to obtain a catalyst.

2. The method for preparing a 3D-printed ultra-low temperature flue gas denitration catalyst according to claim 1, wherein: The mixed slurry comprises, in parts by weight, 70-90 parts of a metal oxide precursor, 2-5 parts of an inorganic binder, 5-15 parts of an organic binder, 2-5 parts of an auxiliary agent, and 1-5 parts of a peptizing agent.

3. The method for preparing a 3D-printed ultra-low temperature flue gas denitration catalyst according to any one of claims 1 to 2, characterized in that: The inorganic binder is one or more of aluminum sol, silica sol, sodium silicate, halloysite nanotubes, bentonite and kaolin; and / or, The organic binder is one or more of polyvinyl alcohol, polyethylene glycol, polyacrylamide, carboxymethyl cellulose and starch; and / or, The auxiliary agent is one or more of sesbania powder, graphite, polytetrafluoroethylene, glycerol, glass fiber and activated carbon; and / or, The peptizing agent is one or more of oxalic acid, citric acid, acetic acid and ammonia water.

4. The method for preparing a 3D-printed ultra-low temperature flue gas denitration catalyst according to claim 1, wherein: The metal oxide precursor, the inorganic binder, the organic binder, the auxiliary agent and the peptizing agent are placed in a ball mill to prepare a mixed slurry. The ball milling speed is 200 r / min-500 r / min, and the ball milling time is 10 min-30 min.

5. The method for preparing a 3D-printed ultra-low temperature flue gas denitration catalyst according to claim 1, wherein: The drying temperature of the printed body is 50° C.-120° C., and the drying time is 2 hours-8 hours; the calcination temperature of the printed body is 300° C.-600° C., and the calcination time is 2 hours-8 hours.

6. The method for preparing a 3D-printed ultra-low temperature flue gas denitration catalyst according to claim 1, wherein: The step S1 comprises: Step S11, preparing an alkaline solution containing an alkali metal or an alkaline earth metal; Step S12, adding the metal oxide support to the alkaline solution and stirring to obtain a mixture; Step S13, placing the mixture in a hydrothermal reactor to perform a hydrothermal reaction to obtain a reactant; Step S14: filtering and drying the reactants to obtain a metal oxide precursor.

7. The method for preparing a 3D-printed ultra-low temperature flue gas denitration catalyst according to claim 6, wherein: The alkaline solution of alkali metal or alkaline earth metal is one or more of sodium hydroxide solution, potassium hydroxide solution, rubidium hydroxide solution, cesium hydroxide solution, magnesium hydroxide solution, calcium hydroxide solution, strontium hydroxide solution, barium hydroxide solution and ammoniacal alkali metal solution; and / or, The metal oxide carrier is one or more of manganese oxide, manganese dioxide, dimanganese trioxide, trimanganese tetraoxide and pentamanganese octoxide.

8. A 3D printed ultra-low temperature flue gas denitrification catalyst, characterized in that: The catalyst is prepared and formed by the preparation method according to any one of claims 1 to 7.

9. The 3D printed ultra-low temperature flue gas denitration catalyst according to claim 8, characterized in that: The catalyst is in the form of spherical, cylindrical, flaky or columnar particles, and / or the diameter of the catalyst is 2 mm to 9 mm, and / or the length of the catalyst is 5 mm to 10 mm.

10. A reactor, characterized in that include: A fixed bed or a fluidized bed and the catalyst according to any one of claims 8 to 9, wherein the catalyst is configured to be packed in the fixed bed or the fluidized bed.

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