Method for producing Fe-doped beta-zeolite catalyst monoliths

Abstract

A method for producing a three-dimensional porous Fe-doped beta-zeolite catalyst monolith of laminated catalyst fibers, comprising: a) preparing a suspension paste of Fe-doped beta-zeolite particles in a liquid aqueous diluent, the suspension further comprising a maximum amount of (50) wt% of a binder material based on the amount of Fe-doped beta-zeolite particles, a maximum amount of (10) wt% each of a plasticizer and a pore-forming material based on the amount of Fe-doped beta-zeolite particles, and a maximum amount of 5 wt% of a gelatinizer based on the amount of Fe-doped beta-zeolite particles, wherein all particles in the suspension have a number-average particle size in the range of 0.05 to 700 μm; and b) passing the paste from step a) through one or more nozzles. A method comprising the steps of: a) extruding to form fibers and depositing the extruded fibers to form a three-dimensional porous catalyst monolith precursor; c) drying the porous catalyst monolith precursor to remove the liquid diluent; and d) performing a temperature treatment of the dried porous catalyst monolith precursor from step c) at a temperature in the range of 300 to 600°C to form an Fe-doped beta-zeolite catalyst monolith, wherein the porous catalyst monolith precursor or porous catalyst monolith is not temperature-treated at temperatures above 600°C, and preferably, no further catalytically active metals, metal oxides or metal compounds are applied to the surface of the Fe-doped beta-zeolite particles, catalyst monolith precursor or Fe-doped beta-zeolite catalyst monolith, except for copper.

Description

[Technical Field]

[0001] This invention relates to a method for producing a three-dimensional porous Fe-doped beta-zeolite catalyst monolith of laminated catalyst fibers, the monolith thus obtained, and its use. [Background technology]

[0002] Typically, inorganic catalysts are manufactured as powders and molded bodies in the form of extruded products, granules, pellets, spheres, tablets, or extruded monoliths or honeycomb structures.

[0003] Current commercially available catalyst molded bodies are limited by their size. The smallest commercially available size is approximately 1.2 mm (for extruded bodies). For certain catalytic applications, using smaller diameter extruded bodies has advantages due to increased geometric surface area and shorter pore diffusion distances. However, such smaller extruded bodies cannot be used in commercial reactor setups because their strength is too low and their pressure drop is too high. For multitubular reactors, it is necessary to fill the reactor tubes with catalyst material very uniformly. To ensure reactor balance, today's catalysts rely on cut extruded bodies or tablets to ensure uniform particle size. Similarly, loading such reactors is time-consuming and labor-intensive. It would be desirable to fill reactors, especially multitubular reactors, with molded bodies of the same size and shape as well as improved mechanical properties. For today's Fe-doped beta-zeolite catalysts (e.g., NO in NH3) x No molded articles offering a combination of these advantages (for selective catalytic reduction or N2O reduction) are known.

[0004] Fe-doped beta-zeolite catalysts can be used as extruded extruders with standard diameters ranging from 1.2 mm to 12.0 mm. Special cross-sections such as star, trilobe, quadrolobe, and ring shapes are possible. Alternatively, tablets with diameters from 1.5 to 20.0 mm are used. Different catalyst shapes result in different pressure drops within the reactor.

[0005] Alternative processes that enable a greater variety of shapes compared to linearly drawn honeycomb structures can be prepared, for example, by rapid prototyping processes. For example, the process described in U.S. Patent No. 8,119,554 includes the production of a molded body by a powder-based rapid prototyping process in which a binder material is selectively introduced into an inorganic catalyst powder to form a three-dimensional structure.

[0006] A further manufacturing process, often called robocasting, can be used. In this method, a paste of catalyst material particles is extruded into strands, which are deposited into stacked layers to form a desired three-dimensional structure. This structure is then dried and heat-treated. The manufacture of a renewable diesel soot particulate filter by the robocasting method is disclosed in U.S. Patent No. 7,527,671.

[0007] Extrusion 3D printing of molecular sieve zeolites for gas absorption applications is described in a contributed paper from Materials Science and Technology 2018 (MS&T18), October 14-18, 2018, pages 33-40. Zeolites 13X, 5A, 4A, and 3A are mixed with bentonite clay as a binder, methylcellulose as a plasticizing organic binder, and poly(vinyl) alcohol (PVA) as a cobinder. A homogeneous aqueous slurry with suitable viscosity is obtained, which is 3D printed to form circular grid discs or square grid designs. 3D printed zeolite 3A and 4A monoliths contained either 90 wt% zeolite, 7 wt% bentonite clay, 2.0 wt% methylcellulose, and 1.0 wt% PVA, or 95 wt% zeolite, 3 wt% bentonite clay, 1.5 wt% methylcellulose, and 0.5 wt% PVA. While the increased hardness after sintering is an indicator of better mechanical strength in the 3D printed zeolite samples, it is also stated that increased hardness after sintering makes them brittle.

[0008] Catalysis Today, 216 (2013), pages 18-23, discloses a macroporous support having a thin active layer of zeolite. Three-dimensional fiber deposition allows for different structures for catalyst supports. A wash-coating method was optimized for coating ZSM-5 onto various types of supports. The fabricated catalyst was evaluated for the conversion of methanol to light olefins.

[0009] Chemical Papers 68(9)1143-1153 (2014) discloses the conversion of methanol to light olefins (MTO) using a structured catalyst. Key aspects of the mass transfer properties of the final catalyst, such as coating thickness, zeolite crystal size, and support structure, are highlighted. The pressure drop as a function of specific geometric surface area is shown for various shapes in Figure 2. For the same specific surface area, the samples exhibit different pressure drops, from high to low: sphere (packed bed), foam, three-dimensional fiber deposition (3DFD)1-3, 3DFD1-1, and honeycomb. The surface of the 3DFD is coated with ZSM-5; see Figure 3.

[0010] Int.J.Appl.Ceram.Technol.,9[5],pages 902-910(2012) discloses ceramic processing techniques for catalyst design: formation, characterization and catalyst examples of ZSM-5 on three-dimensional fiber deposition support structures. (1.1) Lamination and (1.3.5) Lamination of 3DFD supports are disclosed.

[0011] U.S. Patent Application Publication No. 2007 / 0259770 and U.S. Patent Application Publication No. 2009 / 0291824 describe extrusion catalysts, such as honeycomb structures, in which the extrusion paste contains a substantial amount of fiber / fiber filler.

[0012] NO at NH3 xFor selective catalytic reduction, Fe-beta zeolite is often used. Compare Chinese Journal of Catalysis 37(2016), pages 2069-2078. Beta zeolite has a three-dimensional channel structure with 12-member rings assembled from 4, 5, and 6-member rings and is an attractive host material for metal loading. The catalyst is used in the form of pellets, which are crushed to 20-40 mesh.

[0013] Methods and catalysts for the reduction of nitrogen oxides with ammonia using promoted zeolite catalysts are described in many patent applications and patents, such as U.S. Patent No. 4,961,917, European Patent Application Publication No. 3 708 252 A1, International Publication No. 02 / 41991 pamphlet, International Publication No. 03 / 022430 pamphlet, International Publication No. 2013 / 118064 A1 pamphlet, and U.S. Patent Application Publication No. 2013 / 0202524 A1. The catalyst is typically used as a shaped 1.5-3 mm strand prepared by mixing a metal-loaded zeolite beta material with 20-50% by weight of aluminum oxide based on 100% by weight of the resulting mixture. The shaped mixture is calcined at 450°C for 4 hours to obtain the required catalyst sample. See the examples.

Summary of the Invention

Problems to be Solved by the Invention

[0014] In a fixed-bed catalytic reactor, for example, the use of smaller catalyst particles would be necessary to obtain a high packing density with a high external surface area or a low void volume for catalysts for diffusion-limited reactions. In mass transfer-limited reactions, the performance of smaller catalyst particles is better than that of larger extrudates. However, the disadvantage is that smaller extrudates exhibit a higher pressure drop in a packed bed, which could limit their application in chemical reactors. Furthermore, the mechanical strength of these smaller extrudates is typically not sufficient to form a packed-bed reactor on a commercial scale.

[0015] The current 3rd generation N2O reduction catalyst technology is applied in the form of catalyst extrudates. Since the extrudates require a shape with a high external surface area (e.g., star-shaped), they are difficult to manufacture and experience a high level of mechanical wear. In addition, in order to achieve an appropriate gas mixture, a significant amount of the reactor volume (up to 60%) is filled with a packing material that allows for a uniform mixing of NOx, N2O, and the reducing agent.

[0016] An object underlying the present invention is to provide an Fe-doped beta zeolite catalyst having a high external surface area or a high packing density. The catalyst structure should be sufficiently mechanically stable so that a packed catalyst bed can be formed in a reactor, which exhibits a low pressure drop and low wear.

Means for Solving the Problem

[0017] This object is a method for manufacturing a three-dimensional porous Fe-doped beta zeolite catalyst monolith of laminated catalyst fibers, a) preparing a suspension paste of Fe-doped beta zeolite particles in a liquid aqueous diluent, the suspension further comprising a binder material in a maximum amount of 50% by weight based on the amount of Fe-doped beta zeolite particles, a plasticizer and a pore-forming material in maximum amounts of 10% by weight each based on the amount of Fe-doped beta zeolite particles, and a peptizing agent in a maximum amount of 5% by weight based on the amount of Fe-doped beta zeolite particles, and all particles in the suspension having a number average particle diameter in the range of 0.05 to 700 μm, b) extruding the paste of step a) through one or more nozzles to form fibers and depositing the extruded fibers to form a three-dimensional porous catalyst monolith precursor, c) drying the porous catalyst monolith precursor to remove the liquid diluent, d) subjecting the dried porous catalyst monolith precursor of step c) to a heat treatment at a temperature in the range of 300 to 600 °C to form an Fe-doped beta zeolite catalyst monolith ]This is achieved according to the present invention by a method that includes the above, without temperature treatment of the porous catalyst monolith precursor or porous catalyst monolith at temperatures above 600°C, and preferably, without applying further catalytically active metals, metal oxides or metal compounds to the surface of the Fe-doped beta-zeolite particles, catalyst monolith precursor or Fe-doped beta-zeolite catalyst monolith, except for copper and cobalt. [Brief explanation of the drawing]

[0018] [Figure 1] Run 1 - Shows N2O reduction in the presence of 100 ppm N2O + 200 ppm NH3. [Figure 2] Run 2 shows the reduction of SCR with 100 ppm N2O + 1000 ppm NH3 + 1000 ppm NO + 8 volume% H2O. [Modes for carrying out the invention]

[0019] The technical solutions described herein enable very good mixing and thus reduce reactor size requirements, while the 3D micro-extruded shape provides a significantly higher surface area for the active mass due to the narrow diameter of the individual fibers derived therefrom. The present invention makes it possible to provide catalysts with higher performance than existing extruded materials, while also challenging competing monolithic coated solutions. The use of 3D micro-extruded materials enables the application of catalysts in units with physical limitations associated with off-gas reactor processing where conventional catalysts would not function adequately, thus enabling further reduction of N2O emissions in processes and plants that currently lack optimal or arbitrary N2O reduction units. In addition, 3D micro-extruded materials enable the application of this catalyst to automotive applications where conventional extruded materials would result in excessively high pressure drops.

[0020] N2O and / or NO from chemical plants, such as nitric acid or adipic acid plants, stationary generators, and mobile sources, such as off-gas from marine engines. xThis enables the removal of [unclear / unclear]. Marine applications and nitric acid and adipic acid plants are preferred application areas.

[0021] Fe-doped beta-zeolite particles having a number-average particle size in the range of 0.5 to 500 μm can be obtained by following many processes disclosed, for example, in U.S. Patent Application Publication 2013 / 0202524 A1, International Publication 2013 / 118064, International Publication 03 / 022430, International Publication 02 / 41991, European Patent Application Publication 3 708 252 A1, and U.S. Patent No. 4,961,917. The desired or required particle size can be obtained by crushing or grinding the Fe-doped beta-zeolite to the desired particle size. The particle size can be measured optically using a camsizer.

[0022] The manufacturing process for the zeolite material having a BEA-type skeletal structure according to the present invention, which includes YO2 and X2O3, is as follows: (1) A step of preparing a mixture comprising one or more sources of YO2, one or more sources of X2O3, and a seed crystal containing one or more zeolite materials having a BEA-type skeletal structure, (2) A step of crystallizing the mixture obtained in step (1), (3) A step of subjecting the zeolite material having a BEA-type framework structure obtained in step (2) to an ion exchange procedure with Cu and / or Fe, wherein Y is a tetravalent element and X is a trivalent element, and the mixture provided in step (1) and crystallized in step (2) does not contain an organic template as a structure directing agent. Includes, The total amount of Cu and / or Fe in the ion exchange material obtained in step (3) is in the range of 0.1 to 2% by weight, calculated as Fe2O3 and CuO. Preferably, the zeolite material obtained in step (2) contains one or more alkali metals M, where M is selected from the group consisting of Li, Na, K, Cs and two or more combinations thereof. Preferably, Y is selected from the group consisting of Si, Sn, Ti, Zr, Ge and mixtures of two or more thereof. Preferably, one or more sources of YO2 provided in step (1) include one or more silicates, Preferably, one or more sources of YO2 further include one or more silicates in addition to one or more silicates. Preferably, the mixture provided in step (1) includes water glass, Preferably, X is selected from the group consisting of Al, B, In, Ga, and mixtures of two or more of these. Preferably, one or more sources of X2O3 include one or more aluminate salts. Preferably, the molar ratio YO2:X2O3 of the mixture described in step (1) is in the range of 1 to 200. Preferably, the amount of seed crystals contained in the mixture described in step (1) is in the range of 0.1 to 30% by weight, based on 100% by weight of YO2 in one or more sources of YO2. Preferably, the mixture described in step (1) further comprises one or more solvents.

[0023] The treatment process for a gas stream containing nitrogen oxides according to the present invention is: (1) A step of providing a gas stream containing one or more nitrogen oxides, (2) The gas stream provided in step (1) is brought into contact with a transition metal-containing zeolite material having a BEA-type framework structure in order to react with one or more nitrogen oxides. Includes, Zeolite materials can be obtained from synthesis processes without organic templates. Preferably, one or more nitrogen oxides include one or more compounds selected from the group consisting of N2O, NO, NO2, N2O3, N2O4, N2O5, NO3 and mixtures of two or more thereof, preferably one or more compounds selected from the group consisting of N2O, NO, NO2 and mixtures of two or more thereof, and more preferably, one or more nitrogen oxides contained in the gas stream provided in step (1) include N2O and / or NOx Includes, Preferably, the gas stream provided in step (1) contains N2O in an amount that falls within the range of 10 to 10,000 ppmv, preferably 50 to 5,000 ppmv, more preferably 100 to 3,000 ppmv, more preferably 500 to 2,000 ppmv, more preferably 700 to 1,500 ppmv, and even more preferably 900 to 1,100 ppmv. Preferably, the gas stream provided in step (1) contains NO in an amount that falls within the range of 0 to 5,000 ppmv, more preferably 50 to 2,000 ppmv, more preferably 100 to 1,000 ppmv, more preferably 150 to 800 ppmv, more preferably 200 to 600 ppmv, and even more preferably 2,500 to 500 ppmv. x Includes, Preferably, the gas stream provided in step (1) is N2O and NO x NO included in the range of 1:50~5:1, preferably 1:20~2:1, more preferably 1:10~1:1, more preferably 1:5~1:1.5, and even more preferably 1:4~1:2 x :Contains N2O in molar ratio, Preferably, the gas stream provided in step (1) further comprises one or more reducing agents. Preferably, one or more reducing agents comprise one or more compounds selected from the group consisting of hydrocarbons, carbon monoxide, hydrogen, and two or more combinations thereof; preferably, one or more reducing agents comprise one or more hydrocarbons selected from the group consisting of one or more hydrocarbons, more preferably C1-C6 alkanes, more preferably C1-C5 alkanes; more preferably, one or more reducing agents comprise one or more hydrocarbons selected from the group consisting of methane, ethane, propane, and butane; even more preferably, one or more reducing agents comprise methane and / or propane and / or butane, more preferably methane and / or propane; and even more preferably, one or more reducing agents comprise propane. Preferably, one or more reducing agents, preferably one or more hydrocarbons, one or more nitrogen oxides, preferably N2O and / or NO xThe stoichiometric ratio with respect to is in the range of 0.05 to 50, preferably 0.1 to 20, more preferably 0.15 to 10, more preferably 0.25 to 5, more preferably 0.35 to 2, more preferably 0.5 to 1.5, more preferably 0.65 to 1.25, and even more preferably 0.75 to 1.1, Preferably, the reducing agent does not contain ammonia and / or urea, preferably, the reducing agent does not contain ammonia, urea or any derivative of ammonia or urea, more preferably, the reducing agent does not contain a nitrogen-containing compound in which nitrogen is present in a negative oxidation state, and even more preferably, the reducing agent does not contain a nitrogen-containing compound, Preferably, the gas stream provided in step (1) contains 0 to 10% by volume of oxygen, preferably 0.5 to 8% by volume, more preferably 1 to 6% by volume, more preferably 1.5 to 5% by volume, more preferably 2 to 4% by volume, and even more preferably 2.5 to 3.5% by volume of oxygen, Preferably, the gas stream provided in step (1) contains 0 to 10% by volume of H2O, preferably 0.05 to 5% by volume, more preferably 1 to 3% by volume, more preferably 0.1 to 2% by volume, more preferably 0.15 to 1% by volume, and even more preferably 0.2 to 0.5% by volume of H2O, Preferably, the gas stream provided in step (1) contains one or more exhaust gases, preferably one or more exhaust gases from one or more industrial processes, more preferably, the exhaust gas stream contains one or more exhaust gas streams obtained from the production processes of adipic acid, nitric acid, hydroxylamine derivatives, caprolactam, glyoxal, methyl-glyoxal, glyoxylic acid or the combustion process of nitrogen materials (including mixtures of exhaust gas streams from two or more of the above processes), and even more preferably, the exhaust gas stream contains one or more exhaust gas streams obtained from the production process of adipic acid and / or nitric acid, Preferably, the gas stream provided in step (1) is an internal combustion engine, preferably C1 to C 10Includes one or more exhaust gases from an internal combustion engine operating using a fuel containing hydrocarbons or mixtures of two or more thereof, more preferably C1-C8 hydrocarbons or mixtures of two or more thereof, more preferably C1-C6 hydrocarbons or mixtures of two or more thereof, more preferably C1-C5 hydrocarbons or mixtures of two or more thereof, more preferably a gas containing methane and / or propane, and even more preferably a gas containing methane. Preferably, one or more exhaust gases contained in the gas stream provided in step (1) are pre-treated to contain N2O and / or NO x Preferably, the exhaust gas has not been subjected to a catalytic treatment procedure for reducing one or more nitrogen oxides, and more preferably, one or more exhaust gases contain N2O and / or NO x The exhaust gas has not been subjected to a treatment procedure for reducing nitrogen oxides, and more preferably, one or more types of exhaust gas has not been subjected to a treatment procedure for reducing one or more types of nitrogen oxides in advance. Preferably, the contact between the gas flow and the transition metal-containing zeolite material in step (2) is carried out at a temperature within the range of 250 to 550°C, preferably 300 to 500°C, more preferably 325 to 450°C, more preferably 350 to 425°C, more preferably 380 to 420°C, and even more preferably 390 to 410°C. Preferably, the contact between the gas flow and the transition metal-containing zeolite material in step (2) is carried out at a pressure in the range of 1 to 50 bar, preferably 2 to 30 bar, more preferably 3 to 25 bar, more preferably 4 to 20 bar, more preferably 5 to 15 bar, more preferably 6 to 10 bar, more preferably 7 to 9 bar, and even more preferably 7.5 to 8.5 bar. Preferably, the process is a continuous process, and more preferably, the contact between the gas flow and the transition metal-containing zeolite material in step (2) is 1,000 to 100,000 hours. -1 , more preferably 2,500 to 50,000 hours -1 , more preferably 5,000 to 30,000 hours -1, more preferably 10,000 to 25,000 hours -1 More preferably 15,000 to 22,500 hours -1 The test is performed using the gas space velocity per time (GHSV) within the specified range.

[0024] A nitrogen oxide is contained, preferably NO according to the present invention. x and / or apparatus for processing gas streams containing N2O, (i) A catalyst bed provided in fluid contact with a gas flow to be treated, comprising a transition metal-containing zeolite material having a BEA-type skeletal structure, the zeolite material can be obtained from a synthesis process without an organic template, and preferably the catalyst bed is a fixed-bed catalyst or a fluidized-bed catalyst, preferably a fixed-bed catalyst. The apparatus includes, preferably, (ii) One or more devices provided upstream of the catalyst bed for injecting one or more reducing agents into the gas flow It also includes.

[0025] The one or more transition metals contained in the zeolite material in the present invention are preferably selected from the group consisting of Co, Ni, Cu, Fe, Ag, Au, Pt, Pd, Rh and two or more combinations thereof, more preferably from the group consisting of Co, Ni, Cu, Fe and two or more combinations thereof, and even more preferably the zeolite material contains Cu and / or Fe, preferably Fe. Preferably, one or more transition metals are included in the zeolite material as non-skeleton elements. Preferably, the BEA-type framework structure of the zeolite material contains YO2 and X2O3, where Y is a tetravalent element and X is a trivalent element. Preferably, Y is selected from the group consisting of Si, Sn, Ti, Zr, Ge, and mixtures of two or more thereof, and Y is preferably Si. Preferably, X is selected from the group consisting of Al, B, In, Ga, and mixtures of two or more thereof, and X is preferably Al. Preferably, the YO2:X2O3 molar ratio is in the range of 2 to 100, more preferably 4 to 70, more preferably 5 to 50, more preferably 6 to 30, more preferably 7 to 20, more preferably 8 to 15, more preferably 9 to 13, and even more preferably 10 to 11. Preferably, the molar ratio of one or more transition metals to X2O3 contained in the BEA-type framework structure is in the range of 0.005 to 10, more preferably 0.01 to 5, more preferably 0.05 to 2.5, more preferably 0.1 to 1.5, more preferably 0.25 to 1, and even more preferably 0.3 to 0.7. Preferably, the X-ray diffraction pattern of a zeolite material having a BEA-type skeletal structure includes at least the following reflections.

[0026] [Table 1]

[0027] Here, 100% relates to the intensity of the maximum peak in the X-ray powder diffraction pattern. Preferably, the zeolite material having a BEA-type skeletal structure includes zeolite beta, Preferably, the transition metal-containing zeolite material is included in the molded product.

[0028] The catalyst composition of the present invention may include a zeolite having a silica-to-alumina ratio of at least about 10, and a pore structure in which all three crystallographic dimensions are interconnected by pores having an average dynamic pore diameter of at least about 7 angstroms, for example, about 7-8 angstroms, and one or both of the iron and copper accelerators are present in the zeolite in an amount of, for example, about 0.1-30 weight percent, preferably about 1-5 weight percent, of the total weight of the accelerator + zeolite. In addition to beta, the zeolite may include one or more of USY, beta, and ZSM-20. A heat-resistant binder may be mixed with the zeolite. Iron-accelerated beta zeolite is preferred, and selective catalytic reduction removes NO from gas turbine exhaust, etc. x It is being commercialized to remove it.

[0029] In this invention, iron-promoting zeolite beta was an effective catalyst for the selective reduction of nitrogen oxides, such as by the reduction of nitrogen oxides with ammonia.

[0030] Unfortunately, NO is released from the gas turbine exhaust at temperatures exceeding 500°C. x Under harsh hydrothermal conditions such as NO reduction, it has been found that the activity of iron-promoted zeolite beta begins to decrease. This decrease in activity is thought to be due to the destabilization of the zeolite, such as dealuminization and the resulting decrease in metal-containing catalytic sites within the zeolite. x To maintain the overall activity of the reduction, a stabilized iron-promoting aluminosilicate zeolite catalyst containing iron in the form of Fe(OH) can be used. Preferably, the iron accelerator is calculated as a metal and present in an amount of 0.1 to 30 weight percent based on the total weight of the metal and zeolite. Preferably, the iron is present in an amount of 0.5 to 2.5 weight percent based on the metal. Preferably, the zeolite has a silica-to-alumina ratio of at least about 8 and a pore structure in which all three crystallographic dimensions are interconnected by pores having an average dynamic diameter of at least about 7 Å. The stabilized iron-promoting aluminosilicate zeolite preferably contains iron-promoting zeolite beta, Preferably, the zeolite beta has a Si / Al ratio of 10 or less. The stabilized iron-promoting aluminosilicate zeolite is preferably 3680±5cm². -1 It has an FT-IR absorption peak, Preferably, the zeolite has a silica-to-alumina molar ratio of at least about 8 and a pore structure in which all three crystallographic dimensions are interconnected by pores having an average dynamic pore diameter of at least about 7 Å. The aforementioned zeolite is zeolite beta, Preferably, the iron accelerator is calculated as a metal and is present in an amount of 0.1 to 30% by weight based on the total weight of the metal and zeolite. Preferably, the iron is present in an amount of 0.5 to 2.5 weight percent.

[0031] In the present invention, metal-enhanced aluminosilicate zeolite having improved stability can be formed by press-steaming aluminosilicate zeolite at a temperature of 600°C to 800°C for 0.25 to 8 hours, wherein the press-steaming does not provide significant dealuminization of the aluminosilicate zeolite, and thereafter, a metal is added to the press-steamed zeolite. The aforementioned metal is iron, Preferably, the metal is added in an amount of 0.1 to 30% by weight, calculated as metal based on the total weight of the metal and aluminosilicate zeolite. Preferably, the metal is added in an amount of 0.5 to 2.5 weight percent based on the total weight of the metal and zeolite. Preferably, the metal is iron present in an amount of 0.7 to 1.5 weight percent of the total weight of iron and zeolite. Preferably, the zeolite has a silica-to-alumina ratio of at least about 8 and a pore structure in which all three crystallographic dimensions are interconnected by pores having an average dynamic pore diameter of at least about 7 Å. Stabilized aluminosilicate zeolite contains zeolite beta.

[0032] Stable, metal-promoting aluminosilicate zeolites can be prepared by contacting aluminosilicate zeolites with a ranchinide salt by ion exchange, and subsequently adding a metal promoter to the ranchinide-treated aluminosilicate zeolites by ion exchange. Preferably, the lanthanide salt is a cerium salt. The aforementioned metal accelerator is iron, Preferably, the metal accelerator is added in an amount of 0.1 to 30% by weight, calculated as metal based on the total weight of the metal and zeolite. Preferably, the iron is added in an amount of about 0.5 to 2.5 weight percent. The aforementioned zeolite is zeolite beta.

[0033] The stabilized iron-promoting aluminosilicate zeolite catalyst in this invention contains iron in the form of Fe(OH), Preferably, the iron accelerator is calculated as a metal and present in an amount of 0.1 to 30 weight percent based on the total weight of the metal and zeolite. Preferably, the iron is present in an amount of 0.5 to 4 weight percent, for example, 0.5 to 2.5 weight percent, based on the metal. Preferably, the zeolite has a silica-to-alumina ratio of at least about 8 and a pore structure in which all three crystallographic dimensions are interconnected by pores having an average dynamic diameter of at least about 7 Å. Stabilized iron-promoting aluminosilicate zeolite contains iron-promoting zeolite beta, The zeolite beta preferably has a Si / Al ratio of 10 or less.

[0034] The present invention relates to a method for reducing nitrogen oxides with ammonia, comprising contacting a gas stream containing nitrogen oxides and ammonia with a catalyst composition at a temperature of about 250°C to 600°C, the catalyst composition comprising (a) a zeolite having a silica-to-alumina ratio of at least about 10 and a pore structure in which all three crystallographic dimensions are interconnected by pores having an average dynamic pore diameter of at least about 7 angstroms, and (b) an accelerator selected from the group consisting of iron and copper, calculated as a metal and in an amount of about 0.1 to 30 weight percent based on the total weight of the metal and zeolite. Preferably, the accelerator is present in an amount of about 1 to 5 weight percent of the total weight of the catalyst material, and in this specification, preferably the accelerator contains iron. Zeolites are selected from a group consisting of beta, Preferably, the catalyst composition further comprises a heat-resistant binder mixed with zeolite.

[0035] The temperature treatment in step d) can increase the mechanical strength and cohesive force of the monolith and also helps to remove plasticizers and / or organic binders and pore-forming materials. As a result, since transition alumina precursor particles and optionally binders and / or plasticizers and pore-forming materials and / or dopants are used in step a), the Fe-doped beta-zeolite components in the porous catalyst monolith precursor are converted to form an Fe-doped beta-zeolite catalyst monolith.

[0036] Thus, in step a), Fe-doped beta-zeolite particles are used.

[0037] In this respect, the three-dimensional monolith is a single structure made up of at least two stacked layers of fibers.

[0038] Step b) is preferably controlled by a control system dataset or CAD file, as described below, which is implemented on a computer system.

[0039] According to the present invention, Fe-doped beta-zeolite particles can be used in a robocasting process, and heat treatment at temperatures above 600°C is not performed in order to obtain a mechanically stable catalytic Fe-doped beta-zeolite structure exhibiting low pressure drop, high packing density, and high crushing strength.

[0040] The present invention enables the synthesis of catalyst molded articles with high surface area and high strength based on transition alumina. The high surface area is achieved by avoiding high-temperature processing and resulting in small fibers, preferably having a diameter of less than 1.2 mm, which can be continuous fibers or laminated into a 3D structure that can be composed of laminated discontinuous fibers that can be used in commercial applications.

[0041] This invention leads to higher conversion and selectivity levels of Fe-doped beta-zeolite catalysts, resulting in better product yields. The lower pressure drop also increases mass flow rate, enabling higher processing rates per hour, again resulting in better product and space-time yields. It also enables NO removal in the NH3-SCR process at lower reaction temperatures. x This allows the reaction to proceed, which is beneficial for better process economics. It further enables less catalyst aging due to shorter diffusion pathways and shorter residence times. If coke formation occurs throughout the catalyst operation, for example, faster burning of carbon with hot air or steam is facilitated, reducing the time required for such regeneration, which is beneficial for process economics. Furthermore, it is possible to design new reactors that are smaller than the current configuration, resulting in lower investment costs (process enhancement) while maintaining current output. In the case of multi-tube reactors, loading can be made faster, and more reliable process operation can be expected.

[0042] Preferably, the method according to the present invention does not involve temperature or heat treatment at temperatures above 600°C, more preferably above 500°C. Process steps c) and d) are preferably performed at temperatures of 600°C or lower. Most preferably, the temperature treatment is performed at temperatures in the range of 300 to 600°C, more preferably 400 to 500°C.

[0043] The drying in step c) is preferably carried out at a temperature in the range of -100 to less than 500°C, more preferably 0 to 300°C, and most preferably 20 to 150°C.

[0044] Step d) is preferably carried out at a temperature in the range of 400 to 500°C and for a duration of 5 to 120 minutes.

[0045] The method according to the present invention yields a three-dimensional porous transition alumina catalyst monolith in which no further catalytically active metals, metal oxides, or metal compounds are applied to the surface of the Fe-doped beta-zeolite particles or catalyst monolith, and preferably not even in the suspension paste.

[0046] If intended, a small amount of dopant or mixture of dopant, selected from, for example, compounds of Li, Na, K, Ca, Mg, Ba, B, Ga, Si, Ti, Zr, Fe, W, P, or Zn, may be present in the suspension paste in a maximum amount of 10% by weight based on the amount of Fe-doped beta-zeolite particles or mixtures thereof, for example, 0.1 to 10% by weight, preferably 1.0 to 5.0% by weight based on Fe-doped beta-zeolite particles. Preferably, the dopant is not used or added to the suspension.

[0047] The final Fe-doped beta-zeolite may contain small amounts of impurities that could be eligible as dopants, unintentionally! Typical impurities in such cases are Li2O, Na2O, K2O, CaO, MgO, BaO, B2O3, Ga2O3, SiO2, TiO2, ZrO2, ZnO, Fe2O3, as well as chlorides, nitrates, and sulfates. When doping is not intended—which is preferable—the amounts of these should be as low as possible. Typically, in such cases, the amount of such impurities in Fe-doped beta-zeolite is 5% or less, preferably 2.5% or less, and particularly 0.5% or less, based on the Fe-doped beta-zeolite in the monolith. In preferred specific embodiments, the impurity content is less than 0.1% by weight, for example, in the case of ultrapure or high-purity Fe-doped beta-zeolite material, and no dopants are used or added to the suspension.

[0048] Therefore, preferably, the catalyst monolith does not contain additional catalytically active components such as catalytically active metals in the final catalyst monolith, apart from Fe.

[0049] Beta-zeolite can be prepared as described in the above-mentioned patent document.

[0050] The BET surface area of ​​a catalyst monolith, as measured by point adsorption using the BET equation (for example, as described by G. Sandstede et.al., Chem. Ing. Tech. 32(1960), 413), is at least 10 m². 2 It should be / g

[0051] The final catalyst monolith is preferably 10 to 1000 m 2 / g, more preferably 25-800m 2 / g, most preferably 50-800m 2 / g, for example, 50-350m 2 It has a surface area in the range of / g. The surface area is preferably measured by the single-point BET method.

[0052] Pore ​​volume is another important requirement, and it is crucial that the total pore volume, as measured by mercury intrusion or nitrogen physicoadsorption, is sufficiently high. In absolute terms, the total pore volume should be at least 0.05 ml / g.

[0053] In certain embodiments, it may be desirable that the pore volume in pores greater than 50 nm, more preferably greater than 250 nm, and most preferably greater than 500 nm, constitutes a significant portion of the total pore volume.

[0054] In certain embodiments, the ratio of pore volume to total pore volume in pores greater than 50 nm should preferably be greater than 3%. Fe-doped beta-zeolites having these properties have good reactant accessibility, which makes them very suitable for catalytic reactions that require good diffusion of reactants and products through the Fe-doped beta-zeolite catalyst, thereby eliminating diffusion limitation problems as much as possible.

[0055] Pore ​​volume and pore size distribution are determined by mercury porosimetry using the Washburn equation, as described by J. Rouquerol et al. in Pure & Applied Chem., 66(8), 1994, pages 1752-1753. Nitrogen physicoadsorption is described by F. Schueth et al. in Handbook of Porous Solids, Wiley, 2002.

[0056] The pore volume of the final catalyst monolith is preferably in the range of 0.05 to 2.0 ml / g, more preferably 0.1 to 1.5 ml / g, and most preferably 0.2 to 1.2 ml / g.

[0057] For pores larger than 50 nm, the pore volume is preferably in the range of 3-50%, more preferably 5-40%, and most preferably 10-35%, relative to the total pore volume.

[0058] Pore ​​size distribution is another important requirement. In certain embodiments, it may be preferable to obtain a transition alumina catalyst having a multimodal pore size distribution, such as a bimodal pore size distribution.

[0059] In accordance with this specification, a multimodal pore size distribution means a pore size distribution in which, when incremental pore volume is plotted as a function of pore size, the resulting function exhibits a maximum (or mode) within a first pore size range and a maximum (or mode) within a second pore size range. Generally, the maximum (or mode) is the number that occurs most frequently within a particular range of values. With respect to the pore size distribution, the maximum (or mode) pore size is the pore size corresponding to the highest peak in the graph showing the pore size distribution within a particular pore size range or a sub-range that falls within such a range. Thus, in accordance with this specification, a multimodal pore size distribution also means that there should be at least one peak in the graph showing the pore size distribution within the first pore size range, and at least one peak in the graph showing the pore size distribution within the second pore size range. An example is a multimodal pore size distribution with two peaks, as shown in Figures 2 and 3 of European Patent No. 2231559. The pore diameter may be either the pore size or the pore radius.

[0060] Preferably, in a multimodal pore size distribution, the pore size range includes a first pore size range and a second pore size range, and the pore size within the first pore size range is smaller than the pore size within the second pore size range.

[0061] Preferably, the first pore size range is 0.1 to 50 nm (micropores and mesopores), and the second pore size range is greater than 50 nm, for example, greater than 50 nm to less than 1500 nm (macropores). Preferably, the maximum (or mode) in the first pore size range is 5 to 50 nm, more preferably 10 to 30 nm. Furthermore, preferably, the maximum (or mode) in the second pore size range is 50 to 1500 nm, more preferably 100 to 1250 nm.

[0062] Preferably, the pore sizes corresponding to the maximum (or mode) in the first and second pore size ranges are separated by at least 200 nm, more preferably at least 300 nm and at most 1,500 nm, more preferably at most 1,000 nm.

[0063] The pore size distribution is determined using the Washburn equation according to a well-known mercury porosimetry method, as described by J. Rouquerol et al. in Pure & Applied Chem., 66(8), 1994, pages 1752-1753.

[0064] Preferably, the catalyst used in the present invention has a total pore volume of 3-50%, more preferably 5-40%, and most preferably 10-30% in pores having a diameter greater than 50 nm (macropores). Furthermore, preferably, the catalyst has a total pore volume of 50-97%, more preferably 60-95%, and most preferably 70-90% in pores having a diameter of 0.1-50 nm (micropores and mesopores). Even more preferably, the catalyst has a total pore volume of less than 3%, more preferably less than 2%, and even more preferably less than 1% in pores having a diameter greater than 1500 nm. Most preferably, the catalyst has essentially no pore volume in pores having a diameter greater than 1500 nm.

[0065] As shown above, the use of monolithic extruded materials is important in terms of pressure drop with respect to the accessibility of the inner surface of the transition alumina. This also plays a role in eliminating diffusion problems. Another advantageous property of monolithic extruded materials is the fact that the ratio of outer surface area to volume is more favorable than in the case of conventional molded bodies used in catalytic reactions.

[0066] An important aspect of the material of the present invention is its strength properties. As indicated above, a lateral fracturing strength of at least 10 N, preferably at least 20 N, more preferably at least 30 N, most preferably at least 50 N, and especially at least 100 N, and a bulk fracturing strength of at least 0.1 MPa are preferred herein. These parameters form the basis for the suitability of monolithic extruders for use in large-scale reactors such as those in the chemical and petroleum industries. If monolithic extruders meet these requirements, they can be used in large fixed-bed reactors that require very strong catalysts. Lateral fracturing strength and bulk fracturing strength are defined as follows:

[0067] The lateral crushing strength (SCS) of a catalyst monolith according to the present invention, preferably having dimensions of 1.5 cm × 1.5 cm × 1.2 cm (x, y, z axes, z being the stacking direction), is preferably at least 50 N, more preferably at least 60 N, more preferably at least 100 N, and most preferably at least 300 N, when the yz or xy opposing planar side surfaces are pressed.

[0068] The SCS of a molded body is defined as the pressure (in Newtons) at which it will be crushed when processed under pressure.

[0069] The determination of SCS is disclosed, for example, in Oil & Gas Science and Technology - Rev. IFP, 55 (2000), No. 1, pp. 67-85, specifically in section 3.1.1. An example of determining SCS covering the resistance of a molded catalyst to compressive force is as follows: A compressive load is applied to the molded body between the jaws. The force required to break the molded body is measured and recorded in Newtonian units. The operation is performed using a semi-automatic Schleuniger Model 6D hardness tester. The molded body is tested with the YZ or XZ planes facing upright between the measuring jaws. The "START" button is pressed on the Schleuniger 6D. The jaws will slowly approach each other to perform the breaking test. The breaking strength is displayed on the Schleuniger and computer monitor.

[0070] The maximum SCS depends on the material used to prepare the catalyst monolith, as well as the three-dimensional structure and fiber diameter of the catalyst monolith. The more contact points present between individual fiber layers, the higher the lateral fracturing strength will be. Preferably, adjacent layers have at least 10 contact points, more preferably at least 20, and most preferably at least 30, contact points with one adjacent layer. Thus, for a fiber layer with two adjacent layers, the number of contact points is twice the above number. Due to the contact points, the lamination of fiber layers is self-supporting.

[0071] There is no upper limit to the SCS of a catalyst monolith. Typically, the maximum SCS is 100,000 N, and often it is 10,000 N. Therefore, the SCS of the catalyst monolith according to the present invention is preferably in the range of 60 to 100,000 N, more preferably 100 to 100,000 N, and most preferably 300 to 100,000 N.

[0072] The maximum value may also be the maximum value that the machine used to measure the SCS can measure. The maximum value may depend on the size of the monolith. If the monolith is larger than the machine used to measure it, the monolith is cut into a suitable size, preferably 1.5 cm × 1.5 cm × 1.2 cm (x, y, z axes).

[0073] The bulk fracturing strength (BCS) of a catalyst is defined as the pressure (in megapascals) at which 0.5% fine powder (i.e., particles smaller than 0.425 mm) is formed when processed under a piston in a tube. For this purpose, 17 ml of molded catalyst material, pre-selected on a 0.425 mm sieve, is loaded into a cylindrical sample tube (27.3 mm in diameter), and 8 ml of steel beads are loaded on top. The molded material is then processed at various (increasing) pressures for 3 minutes, after which the fine powder is collected and its percentage is determined. This procedure is repeated until a fine powder level of 0.5 wt% is reached.

[0074] Another aspect of material strength is wear, i.e., the amount of material that can break off from the extruded during use. This wear, measured according to ASTM D4058-87, should preferably be less than 10% by weight, more preferably less than 7.5% by weight, and especially less than 5% by weight.

[0075] Fe-doped beta-zeolite extruders having the above properties can be prepared by mixing Fe-doped beta-zeolite particles with a binder and / or suitable plasticizer pore-forming material in the presence of a liquid, usually water, or an inorganic acid dissociating agent such as hydrochloric acid, sulfuric acid, or nitric acid, or an aqueous solution of acetic acid or formic acid to form a paste, and then extruding the paste in the desired form using a suitable die.

[0076] Various types of binder materials can be used, such as those based on silica, clay, or mixtures thereof. Organic materials can also be selected as binders. Mixed oxides may be formed during firing, but due to the small amount of binder, this does not affect the main properties or composition of the monolith.

[0077] Suitable hydroxide precursors for use as binders include gibbsite, bayerite, nordstrandite, and doylite.

[0078] Suitable oxyhydroxide precursors as binders include diaspore, boehmite, pseudoboehmite, and akdalite or todite.

[0079] Common transition aluminas are often derived from hydroxide or oxyhydroxide precursors obtained by the Bayer process and have found many catalytic applications, although high-purity precursor materials (e.g., pseudoboehmite from the Ziegler process for linear alcohol production) are sometimes preferred.

[0080] For the synthesis of Fe-doped beta-zeolite catalysts, mixtures of different hydroxide precursors, mixtures of different oxyhydroxide precursors, or mixtures of binder hydroxides and oxyhydroxide precursors may also be applied.

[0081] To modify the surface properties, acidity, and alkalinity ("doping") of the Fe-doped beta-zeolite catalyst, other elemental precursors may be intentionally included in amounts ranging from 0.1% to 10.0% by weight, based on their content in the final Fe-doped beta-zeolite.

[0082] Suitable binders are alumina hydrates such as boehmite (AlOOH) or bayerite (Al(OH)3), which can be obtained from Sasol as Pural® SB.

[0083] The amount of binder material in the suspension paste is 50% by weight or less, preferably 0.1 to 50% by weight, more preferably 30% by weight, and even more preferably 0.1 to 20% by weight, based on the amount of Fe-doped beta-zeolite particles in the suspension paste. For example, it is preferably in the range of 0.1 to 15% by weight, more preferably 1 to 10% by weight, and most preferably 2.5 to 5%.

[0084] It may be further necessary to use an organic plasticizer to obtain a uniform mixture and convert the mixture into a compound having rheological behavior. The plasticizer may be selected from organic materials such as wax, for example. It is preferable to use a plasticizer that is removed during firing while providing and maintaining the required strength. The amount of plasticizer used in preparing the extruded paste will vary depending on the type of material and the required properties. Generally, it will be 10% by weight or less, preferably 1.5% by weight or less, and more preferably 2.5% by weight or less, based on the amount of its Fe-doped beta-zeolite particles. A preferred plasticizer is polyalkylene oxide, more preferably polyethylene oxide, which is available from Meisei Chemical Industry Co., Ltd. as Alkox E-160.

[0085] Preferably, the amount of plasticizer, when applied to a mixture, should be 10% by weight or less based on the total weight of the suspension paste.

[0086] The pore-forming material is preferably a cellulose material, more preferably a cellulose ether, and most preferably selected from hydroxyethyl methylcellulose (HEMC), methylcellulose (MC), hydroxypropyl methylcellulose (HPMC), or a mixture thereof. The amount of the pore-forming material is 30% by weight or less, preferably 0.1 to 20% by weight, more preferably 0.5 to 10% by weight, and most preferably 1 to 6% by weight, based on the amount of Fe-doped beta-zeolite particles in the suspension paste.

[0087] The deglutinating agent is preferably an inorganic acid, more preferably nitric acid. The amount of deglutinating agent in the suspension paste is 7% by weight or less, preferably 0.05 to 5% by weight, more preferably 0.1 to 3% by weight, and most preferably 0.2 to 1% by weight, based on the amount of Fe-doped beta-zeolite particles in the suspension paste.

[0088] In the method according to the present invention, the suspension paste in step a) contains no fibers at all or only a very small amount of fibers. The fibers are selected from organic and inorganic fibers and may be present in a total amount of 0 to 3% by weight, preferably 0 to 0.9% by weight, more preferably 0 to 0.45% by weight, and most preferably 0% based on the suspension paste. The fibers are elongated solids having a length of at least 4 times, more preferably at least 8 times, and most preferably at least 15 times their (maximum) diameter length. For fibers having a non-circular cross-section, the maximum cross-sectional diameter is considered here. Thus, the paste differs from the pastes described in U.S. Patent Application Publication No. 2007 / 0259770 and U.S. Patent Application Publication No. 2009 / 0291824.

[0089] The final suspension paste preferably has a viscosity suitable for extrusion through a nozzle as described below.

[0090] For the Fe-doped beta-zeolite catalyst, the preferred number-average particle size in step a) is in the range of 0.05 to 700 μm, preferably 0.5 to 500 μm, and more preferably 1 to 250 μm.

[0091] In this regard, the average particle size can be measured by sieving the particles, or by photographic techniques such as laser diffraction or camsizer technology. The average particle size refers to the number-mean particle size or arithmetic mean particle size. For irregular particle shapes, the number-mean maximum particle diameter is measured.

[0092] The suspension paste prepared in step a) of the process according to the present invention preferably has a solid content of 1 to 95% by weight, more preferably 10 to 65% by weight.

[0093] The 3D robocasting techniques used in accordance with the present invention are well-established and can be carried out as described in U.S. Patent No. 7,527,671, U.S. Patent No. 6,027,326, U.S. Patent No. 6,401,795, International Publication No. 2019 / 229040, Catalysis Today 273 (2016), pages 234-243 or Journal of Catalysis 334 (2016), pages 110-115 or U.S. Patent No. 6,993,406.

[0094] 3D robocasting technology can be used with catalyst formulations that can be obtained based on pastes currently used in standard extrusion technology, provided that the particle size is small enough to pass through the extrusion nozzle. The extrusion formulation or paste contains transition alumina particles, hydroxide precursor particles or their oxyhydroxide precursor particles, or mixtures thereof. Binders and / or plasticizers can be added to the extrusion mixture as needed.

[0095] Robocasting technology means extruding through one or more nozzles having a maximum diameter of preferably less than 5 mm, more preferably less than 1 mm, and most preferably less than 0.8 mm. In particular, the nozzle diameter should be in the range of 0.05 mm to 0.4 mm, most preferably 0.2 mm to 0.4 mm. The nozzles may have any desired cross-section, e.g., circular, elliptical, square, star-shaped, or lobe-shaped. The maximum diameter is the maximum diameter of a non-circular cross-section.

[0096] One of the main criteria for robocasting is the use of an extrudeable paste with rheological properties suitable for robocasting technology. The aforementioned literature provides detailed advice on how to obtain the required rheological properties.

[0097] If necessary, viscosity modifiers may be used in the process according to the present invention. Typical viscosity modifiers are celluloses such as carboxymethylcellulose. Preferably, no (additional) viscosity modifiers are used.

[0098] As used herein, the term "porous" defines a monolith as containing channels or pores rather than being a solid block of material. Through-channels or pores can be formed by laminating spatially separated catalyst fiber layers in an ABA or ABACA (also known as ABC) manner. This allows for the formation of pathways with direct lines of sight or pathways without direct lines of sight.

[0099] The porosity is preferably at least 20%, more preferably at least 30%, and may be in the range of 20-90%, and can be determined by nitrogen physicoadsorption, Hg-PV, and He densities. It can be determined by the following formula: Porosity (%) = 100 - [(Density of total microextruded structure / Density of fiber material) × 100]. The density of the total microextruded structure is determined by dividing its total weight by its total volume. The density of the fiber material can be determined by measuring the Hg-PV and He densities.

[0100] The lattice or scaffold formed from fibers is self-supporting, leaving open spaces between the fibers, which results in porosity. Each structure can be found in the aforementioned literature. When used in a reactor, they exhibit a low pressure drop.

[0101] The robocasting process used in accordance with the present invention may also be described as 3D fiber deposition.

[0102] Overview of 3DFD 3D fiber deposition (3DFD) is used to form powders. The 3DFD method is an adaptive manufacturing method in which a high-load paste is extruded by a moving nozzle. By computer-controlled movement of the extrusion head in the x, y, and z directions, porous materials can be produced layer by layer from extruded fibers or strands. After drying, the porous material can be heat-treated.

[0103] The main advantage of this technology is the degree of freedom regarding porous parameters (fiber thickness, interfiber distance, and lamination design).

[0104] A typical flowchart for 3DFD technology follows these steps: Steps to prepare a very viscous paste, Steps to extrude through a narrow nozzle, Steps of computer-controlled deposition of fibers to form a porous periodic structure, Drying and reducing as needed It consists of.

[0105] The first important step is to ensure that no large particles are present in the paste. Therefore, the particle size of the starting material is checked. If there are particles that are too large, the powder is sieved to obtain the desired particle size. As a rule of thumb, the largest particles (represented by the D99 value) should preferably be at least 5 times smaller than the nozzle size that will be used, and more preferably at least 10 times smaller.

[0106] In the next step, the powder is mixed with a solvent / diluent (e.g., water), and additives such as binders and plasticizers are added as needed to obtain a viscous paste. Good mixing to achieve a homogeneous paste (minimizing the incorporation of aggregates or air bubbles) is a prerequisite for a smooth and reproducible process. Powder loading of functional materials depends on the specific surface area, particle size distribution, and powder morphology. Generally, as the particle size of the powder decreases, the viscosity of the paste will increase. Therefore, solid loading needs to be reduced for these powders. Plasticizers can be added, apart from organic or preferably inorganic binders, to control the rheological behavior of the paste. In some cases, defoamers are also added to avoid air bubbles in the paste.

[0107] After mixing and degassing, the paste is transferred to a paste reservoir and mounted on a 3DFD setup. A nozzle, preferably made of plastic or metal (less than 200 μm), is attached to the paste reservoir. Paste extrusion is achieved, for example, by a positive displacement pump or a screw pump. During deposition, it may be necessary to control the drying conditions.

[0108] After drying at room temperature (or under controlled atmosphere and temperature), the 3DFD structure is dried and heat-treated as needed. Heat treatment at temperatures above 1000°C is not required.

[0109] 3DFD process experimental procedure Achieving a smooth process and tight control in the extrusion of thin filaments often requires adjustments to both the paste formulation and the experimental setup. The main process parameters that must be addressed are listed below. parameters Particle size distribution of the starting material Paste preparation and mixing procedure Paste formulation Degassing and paste reservoir filling Design of a sedimentation platform Nozzle height control Interlayer turn and transition programming Adjustment of extrusion speed versus movement speed Dry conditions during deposition

[0110] For a further explanation of the process, please refer to the above-mentioned literature.

[0111] The lamination design is preferably as shown in Figures 1 and 2 of U.S. Patent No. 7,527,671. Most preferably, a 1-3-1 pattern or 3DFD structure 1-3 or 1-1 as shown in Figure 3 of Chemical Papers 68(9), pages 1143-1153 (2014), or a (1.1) lamination or (1.3.5) lamination as shown in Figure 1 of Int. J. Appl. Ceram. Technol. 9[5], pages 902-910 (2012).

[0112] The liquid diluent used may be selected from water and organic liquid diluents. Preferably, the liquid diluent mainly contains water or is water.

[0113] Drying is preferably carried out at a temperature in the range of -100 to 500°C, more preferably 0 to 300°C, and most preferably 20 to 150°C.

[0114] The porous catalyst monolith precursor or porous catalyst monolith is not treated at temperatures above 600°C, preferably above 550°C, and more preferably above 500°C.

[0115] The monolith of the laminated catalyst fiber is preferably three-dimensionally structured by depositing extruded fibers in a regular, repeating laminated pattern to form a three-dimensionally structured porous catalyst monolith precursor (periodically structured catalyst).

[0116] A monolith can be formed from a single continuous extruded fiber or from a plurality of individual extruded fibers.

[0117] Preferably, the regular repeating lamination pattern consists of laminated layers of extruded fibers, in each layer, at least 50% by weight, more preferably at least 90% by weight, of the extruded fibers or fibers are deposited parallel to each other and spatially separated from each other. The parallel deposits may be straight or curved. Alternatively, they may be deposited / laminated in a circular pattern with radial intermediate layers, such as a spiderweb pattern.

[0118] More preferably, at least 50% by weight, most preferably at least 90% by weight, of the extruded fibers or fibers are deposited as linear strands that are parallel to each other and spatially separated from each other, the orientation of the strands in each layer differs from the orientation in adjacent layers, thereby creating a porous structure with contact points between strands of adjacent laminates. Alternatively, multiple spiderweb patterns can be laminated, and each pattern layer may preferably be rotated relative to its adjacent pattern layers.

[0119] An example of a stack of layers arranged alternately at a 90° angle in the direction is shown in Figures 1 and 2 of U.S. Patent No. 7,527,671.

[0120] The fibers or strands preferably have a thickness of 10 to 5000 μm, more preferably 10 to 1000 μm, and most preferably 150 to 500 μm.

[0121] They are preferably spatially separated from each other by 10 to 5000 μm, more preferably 100 to 1000 μm, and most preferably 200 to 800 μm.

[0122] One example is the stacking of 360 μm strands spaced 650 μm apart.

[0123] A typical monolith size is 1 mm. 3 Preferably 1 mm 3 ~100m 3 More preferably 3mm 3 ~300m 3 That is the case.

[0124] The monolith may have any desired shape. Preferably, it may be in the form of a cylinder, cuboid, sphere, ellipsoid, tablet, or polygon with a circular or elliptical cross-section.

[0125] In contrast, a typical extrusion process for transition alumina catalyst extruders yields extruders with a minimum diameter of 1.2 mm. Depending on the formulation, these extruders have a strength (lateral fracturing strength) of less than 10 N or less than 100 N, as measured by the SCS method.

[0126] Structures manufactured from 360 μm fibers, a 650 μm interfiber distance, and ABAB or ABC lamination exhibit a lateral fracture strength of over 100 N for 1.5 cm-1.5 cm-1.5 cm structures.

[0127] Therefore, the process according to the present invention results in a catalyst structure having high strength, coupled with high porosity, high geometric surface area, and high packing density.

[0128] The present invention also relates to a three-dimensional porous catalyst monolith of laminated catalyst fibers that can be obtained by the above process.

[0129] The present invention further relates to the use of these monoliths as catalysts in selective catalytic reduction reactions. Preferably, the reaction involves a gas phase, a liquid phase, or a liquid / gas mixture phase. Refer to the above-mentioned patents and non-patent documents.

[0130] The present invention further relates to a control system dataset, which, when implemented in additive manufacturing equipment, includes a plurality of control commands that prompt the additive manufacturing equipment to produce a three-dimensional porous catalyst monolith or a three-dimensional porous catalyst monolith precursor as described above.

[0131] Additive manufacturing equipment includes, for example, 3D fiber deposition (3DFD), 3D printing, stereolithography, filament filament deposition (FFF), or laser sintering. These machines or apparatuses are used to form powders or pastes for creating three-dimensional catalyst monoliths or their precursors. Therefore, additive manufacturing equipment can be a 3D fiber deposition printer, a 3D printer, a stereolithography apparatus, or a laser sintering apparatus. These manufacturing machines or apparatuses are typically computer-controlled using CAD files (computer-aided design files). CAD files contain information about the three-dimensional structure of the porous catalyst monolith or its precursor and are required to operate the additive manufacturing equipment.

[0132] This CAD file, which may also be described as a control system dataset, contains multiple control commands that drive a moving nozzle in an additive manufacturing facility, such as a 3D fiber deposition machine. The control system dataset may also be described as a control system data record or data drive set. The control system dataset or CAD file contains all the information necessary to drive the additive manufacturing facility to produce a monolith or monolithic precursor. This meaning is encompassed by the term "drive" as used above. The control system dataset and control commands are typically electronic data stored on a computer's CD, DVD, USB stick, hard drive, or SSD drive, or on a suitable data storage device that can be attached to the computer.

[0133] Control system datasets are typically loaded into a computer that controls additive manufacturing equipment before printing or extruding 3D structures. Therefore, the term "implementation" typically means loading control system data or control instructions into a computer system that operates additive manufacturing equipment. Thus, the additive manufacturing equipment, in this case, implements the control instructions into it.

[0134] The Fe-doped beta-zeolite catalyst monolith of the present invention exhibits a lower pressure drop, higher activity, and higher selectivity compared to conventional extruded materials. Because a larger outer surface area of ​​the catalyst faces the reactants, more catalyst is immediately available. Therefore, the residence time of the reactants in the catalyst can be shortened for faster transport. As a result, fewer byproducts are formed.

[0135] The robocasting process enables the production of three-dimensional porous catalyst monolithic structures of laminated catalyst fibers having an increased outer surface area and / or an increased lateral fracturing strength of preferably at least 50N, more preferably at least 60N, compared to conventional extruded materials.

[0136] Furthermore, due to the orderly lamination of the fibers, a higher catalyst density can be achieved within the reactor. By using regularly laminated catalyst fibers prepared according to the present invention, a packing density of up to 70% is possible.

[0137] The lower pressure drop allows for working with smaller fiber diameters compared to single extruders.

[0138] The present invention is further illustrated by the following embodiments. [Examples]

[0139] Examples of 3D microextrusion catalysts: Fe-doped (template-free) beta-zeolite (Fe-TF-beta): Nitric acid for dissociation, Pural SB (Al2O3 binder) Avoid low pH < 2.9 to prevent aluminum removal and damage to the zeolite framework. Final firing T<500℃ CoA - BET ≥ 480 m² / g - 2.8-3.5 wt% Fe, 34-36 wt% Si, and 6.8-7.2 wt% Al → SAR 9-11, low Na (≤0.05 wt% Na as Na2O) - XRD: Relative crystallinity ≥ 95% or 71-73% - LOI:≦10% by weight Target particle size: d10 1~2μm, d50 1~6μm, d90 2~25μm Walocel® MW 15000 GB Dow / Dupont NaCl (0.5-3%) Hydroxyethylmethylcellulose (CAS: 9032-42-2) HEMC Alkox E-160 Kowa Europe GmbH or Meisei Chemical Industry Co., Ltd. EO homopolymer High viscosity, approximately 4,000,000 MW, approximately 0.5% by weight → 100-200 mPa·s (aqueous solution) First extruded: Piston press, Sasol's Pural® SB as binder, HNO3 for decapsulation, zeolite content: 70, 75, and 80% by weight Extrusion test 3mm extruded Walocel®, PEO, nitrate, zeolite binder, water Key parameter: HNO3 concentration → less than 1% by weight for stable extrusion using a 3.0 mm die, but with compromises in mechanical properties and pore volume (Hg-PV < 0.4 ml / g). Recipe (Total is over 100% by weight and does not contain acid or water) - Fe-TF-Beta 200kg (70% weight) - Pural SB (registered trademark) 109kg (30% by weight) - Nitrate 58% 1.6kg (without HNO3) - Alkox E-160 3.1kg→PEO (1% by weight) - Walocel MW15000 GB 9.3kg (3% by weight) - Water 206kg Addition order - MC+Fe-TF-Beta+Pural(registered trademark)SB (dry mixing) - H2O (activation, DAC mixture) - HNO3 solution (peptization) - Fe-TF-beta (solids content adjustment) - "Aging" = overnight

[0140] 3D microextruded porous Fe-doped beta-zeolite catalyst monolith A suspension was prepared from the above components, including Fe-doped beta-zeolite particles, water, and acid (HNO3). The components were manually added and mixed to obtain rheological properties suitable for extrusion through a 400 μm nozzle. The powder particle size was selected to enable this extrusion. The suspension was placed into a dispensing unit consisting of a syringe container and a nozzle. The unit was mounted on a microextruder. The microextruder is a computer numerical control (CNC) machine programmed to move according to a clearly defined pattern and within a clearly defined shape. The CNC machine was programmed to continuously deposit the filament layer by layer in a predetermined pattern. Deposition parameters, such as the distance between the nozzle and the surface of the structure, the nozzle movement speed, air pressure, and ambient temperature and airflow, were adjusted. The 3D structure was constructed in a box by depositing the filament layer by layer according to the programmed pattern and required dimensions. All 3D structures were then dried at 80°C.

[0141] A) A porous Fe-doped beta-zeolite catalyst monolith was formed by applying a temperature treatment at 450°C. The dimensions of the monolith structure after temperature treatment were 1.91 cm × 1.90 cm × 0.74 cm (length, width, height). The porous properties of the monolith were found to be a BET surface area of ​​184 m² / g, a total pore volume of 0.73 mL / g, and SCS > 720 N.

[0142] No to NO x experiment NO removal from 3D-micro-extruded Fe-doped beta-zeolite catalysts x For testing purposes, 25 cc of catalyst was loaded into a 1-inch OD (0.834-inch ID) x 4-foot stainless steel fixed-bed downflow reactor.

[0143] A thermowell containing five thermocouples was installed in the reactor.

[0144] The reactor was heated by a furnace loaded with catalyst so that the catalyst was located in the central part of the furnace.

[0145] Catalyst mass loading was determined by multiplying the catalyst bulk density by 25 cc.

[0146] In the case of the cylinder [Example 1B], the monolithic structure was prepared using a 1-3 stacking pattern of 3DFD structure, as shown in Figure 4 of Catalysis Today 216 (2013), page 21. In each layer, five strands with a diameter of 1.5 mm were deposited. The spacing between two strands was also 1.5 mm. In contrast to the photograph shown in Figure 4(a) of Catalysis Today 216 (2013), page 21, one continuous strand was deposited in a zigzag pattern in each layer, providing linear parallel strands connected by their U-shaped connecting portions, thereby giving one continuous strand per layer. The resulting cylindrical monolith had the following nominal dimensions: OD = 20.8 mm, height = 17.0 mm with a nominal particle mass of approximately 3 g. The cylindrical monolith was formed so that it could be stacked in a single row in the reactor.

[0147] The nozzle size was appropriately adjusted to prepare these cylindrical monoliths.

[0148] In the case of the cylinder [Example 1C], the bulk density was determined based on the normal packing density of a cylinder element having the following nominal dimensions: OD=20.8mm, ID=5.56mm, h=16.74mm with a nominal particle mass of 2.814g. The cylinders were formed so that they could be stacked in a single row in the reactor with a thermowell protruding through a cut-out central hole.

[0149] In all cases, 1 / 8-inch Denstone spheres were used as floor supports and in the preheating zone above the catalyst bed to provide a surface area for the raw materials to vaporize.

[0150] After loading, the reactor was purged with 300 sccm of N2 for approximately 30 minutes to remove air, and then heated to 400°C while flowing N2, and held for at least 4 hours.

[0151] After catalyst pretreatment was complete, the reactor was cooled to 200°C and pressurized to 14.5 psig. Once the pressure and temperature stabilized, the N2 flow was stopped, and a feed consisting of 100 ppm N2O, 1000 ppm ammonia, and 8% by weight water in an argon carrier gas was subjected to GHSV = 50.00 hr. -1 The gas was introduced into the reactor at a rate of , and GHSV is defined as the volumetric flow rate of gas per unit volume of catalyst. The reactor was maintained under these conditions for approximately 24 hours at a maximum temperature of 500°C.

[0152] Product analysis was performed using an online gas chromatograph equipped with a flame ionization detector (FID), a heated sample injection valve, and an HP-PLOT Q capillary column (30 m × 0.320 mm × 20 μm). Reaction effluent was sent to the GC through a heated sample line at approximately 180-200°C and injected approximately every 15 minutes.

[0153] The following amount: Percent N 20 and NO x The conversion rate was calculated and used to evaluate and compare catalyst performance.

[0154] test Test conditions: ·Catalyst B M_Kat = 14.5g GHSV = 50,000hr -1 ·Total flow rate 1816l / h ·Temperature: 250, 290, 310, 350, 410, 450, 500℃ Run 1: Argon carrier gas containing 100 ppm N2O, 200 ppm NH3, and 10% O2 Run 2: Argon carrier gas containing 100 ppm N2O, 1000 ppm NH3, 1000 ppm NO, 10% O2, and 8% H2O.

[0155] Figure 1 shows the reduction of N2O in run 1 - NH3 100 ppm in the presence of N2O + 200 ppm NH3.

[0156] In the presence of 200 ppm NH3, the N2O conversion rate curve shifts slightly to lower temperatures, but 350°C is still required to achieve a significant N2O conversion.

[0157] Figure 2 shows the reduction of SCR + N2O in run 2 - 100 ppm N2O + 1000 ppm NH3 + 1000 ppm NO + 8 volume% H2O.

[0158] In the presence of 100 ppm NO and NH3, a maximum N2O conversion rate of 80% can be obtained at 500°C for fresh and HT-aged Fe BEA catalysts. In stoichiometric feed (NH3 / NO ratio = 1), NO2 formation is not observed up to 500°C.

Claims

1. A method for producing a three-dimensional porous Fe-doped beta-zeolite catalyst monolith of laminated catalyst fibers, a) A step of preparing a suspension paste of Fe-doped beta-zeolite particles in a liquid aqueous diluent, wherein the suspension further comprises a binder material in a maximum amount of 50% by weight based on the amount of Fe-doped beta-zeolite particles, a plasticizer and a pore-forming material in a maximum amount of 10% by weight each based on the amount of Fe-doped beta-zeolite particles, and a gelatinizer in a maximum amount of 5% by weight based on the amount of Fe-doped beta-zeolite particles, and all particles in the suspension have a number-average particle size in the range of 0.05 to 700 μm. b) The step of extruding the paste from step a) through one or more nozzles to form fibers and depositing the extruded fibers to form a three-dimensional porous catalyst monolith precursor. c) A step of drying the porous catalyst monolith precursor to remove the liquid diluent, d) The step of performing the temperature treatment of the dried porous catalyst monolith precursor from step c) at a temperature in the range of 300 to 600°C to form the Fe-doped beta-zeolite catalyst monolith. A method comprising the above, wherein the porous catalyst monolith precursor or porous catalyst monolith is not subjected to temperature treatment at a temperature exceeding 600°C, and preferably, no further catalytically active metals, metal oxides or metal compounds are applied to the surface of the Fe-doped beta-zeolite particles, the catalyst monolith precursor or Fe-doped beta-zeolite catalyst monolith, except for copper.

2. The method according to claim 1, wherein the pore-forming material is a cellulose material, preferably a cellulose ether, and more preferably selected from hydroxyethyl methylcellulose, methylcellulose, hydroxypropyl methylcellulose, or a mixture thereof.

3. The method according to claim 1 or 2, wherein the Fe-doped beta-zeolite can be obtained from a synthesis process without an organic template.

4. The method according to any one of claims 1 to 3, wherein in step b), the nozzle has a maximum diameter of less than 5 mm, preferably less than 1 mm.

5. The method according to any one of claims 1 to 4, wherein the monolith of the laminated catalyst fibers is three-dimensionally structured by depositing the extruded fibers in a regular repeating laminated pattern to form a three-dimensional structured porous catalyst monolith precursor, preferably the regular repeating laminated pattern consists of laminated layers of extruded fibers, in each layer at least 50% by weight of the extruded fibers are deposited parallel to each other and spatially separated from each other, or form a spiderweb pattern, preferably the monolith is formed from one continuous extruded fiber or a plurality of individual extruded fibers.

6. The method according to claim 5, wherein at least 50% by weight of the extruded fibers are deposited as linear strands that are parallel to each other and spatially separated from each other, or a plurality of spiderweb patterns are laminated, and the orientation of the strands in each layer differs from the orientation in adjacent layers, thereby creating a porous structure having contact points of strands in adjacent layers.

7. The method according to any one of claims 1 to 6, wherein the plasticizer is an organic plasticizer, preferably a polyalkylene oxide, more preferably a polyethylene oxide, and / or the decoagulant is an inorganic acid, preferably nitric acid.

8. The method according to any one of claims 1 to 7, wherein an inorganic binder is used, preferably a binder material selected from the group consisting of alumina hydrate, clay, silica or a mixture thereof, more preferably boehmite, bayerite or a mixture thereof.

9. The Fe-doped beta-zeolite catalyst monolith is 50 m ２ The method according to any one of claims 1 to 8, wherein the Fe-doped beta-zeolite catalyst monolith has a BET surface area greater than 0.25 ml / g, and / or the Fe-doped beta-zeolite catalyst monolith has a pore volume greater than 0.25 ml / g, and / or the Fe-doped beta-zeolite catalyst monolith has a unimodal or multimodal pore size distribution.

10. The method according to any one of claims 1 to 9, wherein the suspension paste in step a) contains fibers selected from organic fibers and inorganic fibers in an amount of 0 to 3% by weight, preferably 0 to 0.9% by weight, more preferably 0 to 0.45% by weight, and most preferably 0% based on the suspension paste, and / or the suspension paste in step a) contains Fe-doped beta-zeolite particles in an amount of 60 to 90% by weight, preferably 65 to 85% by weight, and more preferably 70 to 80% by weight based on the suspension paste.

11. A three-dimensional porous catalyst monolith of laminated catalyst fibers that can be obtained by the method according to any one of claims 1 to 10.

12. NO ｘ Use of a three-dimensional porous Fe-doped beta-zeolite catalyst monolith of laminated catalyst fibers according to claim 11 in a selective catalytic reduction reaction.

13. The above reaction is N ２ The use according to claim 12, which reduces oxygen.

14. The use according to claim 12 or 13, wherein the reduction is carried out in the presence of ammonia.

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