Method for producing hydrogen using a ruthenium-containing supported catalyst

Abstract

The present invention relates to a method for producing hydrogen from an ammonia-containing gas using a supported catalyst in the form of a ruthenium-conjugated support, and to the use of such a ruthenium-conjugated support in a method for producing hydrogen. The method comprises providing a supported catalyst in the form of a ruthenium-conjugated support, the support comprising a refractory oxide as the supporting material, being cylindrical, and having at least three spaced channels extending completely through the support, one of which extends along the central longitudinal axis.

Description

[Technical Field]

[0001] The present invention relates to a method for producing hydrogen from an ammonia-containing gas using a supported catalyst in the form of a ruthenium-contaminated support, and to the use of such a ruthenium-contaminated supported catalyst in a method for producing hydrogen.

[0002] Energy generation from "green" energy sources has become increasingly important in recent years. In particular, the production and use of hydrogen as a clean energy source and alternative to fossil fuels is the subject of intensive research.

[0003] Hydrogen can be obtained, for example, by the decomposition of ammonia. 2NH3 → 3H2 + N2

[0004] Unlike fossil fuel-based manufacturing methods, this reaction does not produce environmentally harmful by-products.

[0005] Due to its advantages such as high energy density, simple and established manufacturing and transportation, and long-term storage capacity, ammonia is considered a promising hydrogen carrier. In the catalytic decomposition of ammonia to produce hydrogen, noble metal catalysts (usually ruthenium-based and / or platinum-based) or non-noble metal catalysts (usually iron-based and / or nickel-based) can be used.

[0006] Ammonia cleavage is an endothermic reaction, and therefore favors high temperatures. Currently available catalysts, typically nickel-based catalysts, may require temperatures of 700°C to 900°C. From a process engineering perspective, it is advantageous to keep the temperature as low as possible to reduce the energy required for heat generation and maintain a low heat load on the reactor system.

[0007] The suitability of ruthenium as a catalytically active component for this reaction has long been known. For example, already in 1954, Amano and Taylor described the suitability of alumina-supported ruthenium for this reaction (J. Am. Chem. Soc. 1954, 76(16) 4201-4204). However, catalyst performance depends on the support material, the shape of the catalyst, the production method, and in particular the ruthenium precursor compound used. Known catalysts have a relatively high metal content and require high process temperatures. Since ruthenium is an expensive noble metal, a high metal content is undesirable.

[0008] Typically, ruthenium chloride is used as a ruthenium precursor compound for the production of ruthenium-containing supported catalysts. In this connection, Japanese Patent Application Laid-Open No. 1-085601(A) describes that catalysts produced in this manner must be thoroughly washed to reduce the halogen content to a level compatible with the reactor system.

[0009] The use of catalysts in the form of ruthenium-impregnated supports is also known, for example from WO 2019188219 A1. However, no particularly suitable supports are disclosed. Nevertheless, as recognized in the present invention, the shape of the support used has a great influence on the efficiency of the process.

[0010] The technical problem to be solved by the present invention is to provide a method for producing hydrogen from ammonia-containing gas that can be carried out at a low operating temperature in the range of 450°C to 650°C.

[0011] Furthermore, it was an object of the present invention to provide a supported catalyst particularly suitable for such a method, which results in the lowest possible pressure drop and is therefore suitable for use in large-scale processes.

[0012] Furthermore, one object of the present invention is to provide a supported catalyst that exhibits increased stability under process conditions. In this context, stability refers to both the thermal stability and chemical stability of the catalytically active component, as well as the physical stability and thermomechanical stability of the support and the entire supported catalyst. In particular, the supported catalyst needs to have high mechanical stability and low wear behavior.

[0013] This object is at least partially achieved by a process for producing hydrogen from an ammonia-containing gas, i) providing a supported catalyst in the form of a ruthenium-doped support, wherein the support is comprising a refractory oxide as a support material, cylindrical in shape, and comprising at least three mutually spaced channels extending completely through the support, one of said channels extending along a central longitudinal axis; ii) contacting said supported catalyst with an ammonia-containing gas.

[0014] In the context of the present invention, it has surprisingly been found that the use of a ruthenium-containing supported catalyst provided in the form of a support having a specific shape completely or partially solves at least some of the problems identified in the prior art.

[0015] It is considered that the shape of the support has a beneficial effect on ammonia decomposition. Ammonia decomposition is a volume-increasing reaction (the number of particles doubles: 2 molecules of ammonia are converted into a total of 4 molecules, namely 3 molecules of hydrogen and 1 molecule of nitrogen). It is considered that the advantageous effect of the supported catalyst used according to the present invention can be attributed to the expansion of available geometric voids in the catalyst body.

[0016] In particular, the supported catalyst used according to the present invention is particularly suitable because it provides advantageous radial mass transfer during the process and low pressure drop in the reactor.

[0017] Furthermore, the supported catalyst for ammonia decomposition according to the present invention has advantageous wear behavior and increased mechanical stability.

[0018] Furthermore, the method according to the present invention has a good ammonia conversion rate, and therefore, performance in hydrogen production is improved.

[0019] The present invention relates to the production of hydrogen from ammonia-containing gas.

[0020] Ammonia-containing gas is understood to be a gas or gas mixture containing 50 vol.% to 100 vol.% ammonia. Ammonia-containing gas may also contain other components that do not affect the decomposition reaction, such as inert gases like nitrogen, helium, or argon. For example, ammonia-containing gas may consist of 50 vol.% to 100 vol.% ammonia, 0 vol.% to 50 vol.% helium, 0 vol.% to 50 vol.% argon, 0 vol.% to 5 vol.% water, 0 vol.% to 20 vol.% oxygen, 0 vol.% to 50 vol.% nitrogen, 0 vol.% to 50 vol.% hydrogen, and 0 vol.% to 5 vol.% impurities other than ammonia, helium, argon, water, oxygen, nitrogen, and hydrogen, with a total vol.% of 100 vol.%.

[0021] Advantageously, the ammonia-containing gas contains at least 70 vol.%, particularly at least 80 vol.%, and especially preferably at least 90 vol.% of ammonia.

[0022] Advantageously, the ammonia-containing gas contains 3 vol.% or less of water, particularly 2 vol.% or less, and most preferably 0.2 vol.% or less. Particularly preferably, the ammonia-containing gas may be anhydrous.

[0023] Advantageously, the ammonia-containing gas contains 15 vol.% or less of oxygen, particularly 10 vol.% or less, and especially preferably 5 vol.% or less. In particular, the ammonia-containing gas does not need to contain oxygen.

[0024] The ammonia-containing gas may already contain nitrogen. Preferably, the nitrogen content is 40 vol.% or less, particularly 20 vol.% or less, especially preferably 10 vol.% or less, and most preferably 5 vol.% or less. The presence of nitrogen may be particularly advantageous during the initial stages of the method. The ammonia-containing gas does not need to contain nitrogen.

[0025] The ammonia-containing gas may already contain hydrogen. Preferably, the hydrogen content is 40 vol.% or less, particularly 30 vol.% or less, and especially preferably 10 vol.% or less. The ammonia-containing gas does not need to contain hydrogen.

[0026] Furthermore, as described above, the ammonia-containing gas may contain impurities such as CO, CO2, hydrocarbons, heavy metals, halogens, phosphorus-containing compounds, and / or sulfur-containing compounds. Preferably, the proportion of such impurities is less than 3 vol.%, and more particularly less than 1 vol.%. It has been found that a proportion of sulfur-containing compounds is less than 100 ppm, and more particularly less than 10 ppm, and especially when the ammonia-containing gas does not contain sulfur-containing compounds.

[0027] The composition of the ammonia-containing gas can be changed during the process. For example, it may be advantageous to initially use an ammonia-containing gas with a nitrogen content of more than 3 vol.% and then reduce the nitrogen content.

[0028] A supported catalyst is provided in the method according to the present invention. Therefore, the method is carried out in the presence of the supported catalyst. "Catalyst" is a catalytically active material for a particular application. A supported catalyst is generally understood to mean a catalyst that contains a supported material and whose surface is conjugated with a catalytically active component. The supported material serves as a stable base for the catalytically active material and must be stable under the selected reaction conditions. Typically, the supported material itself does not possess catalytic activity.

[0029] A supported catalyst is a ruthenium-conjugated support. That is, a supported catalyst is provided in the form of a ruthenium-conjugated catalyst molded body. The terms “ruthenium-conjugated support” and “ruthenium-containing supported catalyst” are used synonymously in this application. Such a supported catalyst is also called a bulk catalyst. A bulk catalyst is provided as a loose bed in a reactor for heterogeneous catalytic reactions. The bed is designed to provide a large surface area as a contact area between the solid catalyst and the fluid reactants, on the one hand, but on the other hand, to prevent excessive pressure loss across the reactor. Bulk catalysts have an advantage over powder catalysts in that they can be used in continuous processes, such as fixed-bed reactors.

[0030] The carrier is cylindrical. Therefore, the shape of the carrier can be described by its length along the central axis and its outer diameter. This central axis is also referred to as the longitudinal axis in the context of this application.

[0031] In preferred embodiments, the carrier has a length and / or outer diameter in the range of 0.5 mm to 50 mm, preferably 1 mm to 30 mm, and particularly 2 mm to 20 mm. It has been found that a length-to-outer diameter ratio of 1:1 to 1:5, particularly 1:1 to 1:3, is advantageous.

[0032] In the context of this application, a cylindrical carrier is understood to mean both a carrier including a flat circumferential surface and a carrier including a notch or groove extending along the circumferential surface. The notch or groove may be positioned at any angle with respect to the direction of the longitudinal axis of the carrier. For example, the notch or groove may extend spirally along the circumferential surface of the carrier. However, preferably, the notch or groove extends parallel to the longitudinal axis of the carrier.

[0033] The carrier comprises at least three spaced channels that extend completely through the carrier. In other words, the channels extend from the top surface to the bottom surface of the carrier. The top and bottom surfaces of the carrier are also called end faces. The channels are tubular cavities that are particularly gas-permeable, i.e., allow gas flow. Such channels have been found to be particularly advantageous because, on the one hand, they suppress pressure loss in the catalyst bed, and on the other hand, they increase the available catalytically active surface.

[0034] The carrier may include, for example, channels 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15. It has been found that it is advantageous when the carrier includes channels 3 to 10, particularly channels 5 to 8.

[0035] One of the channels extends along the central longitudinal axis of the carrier; that is, the central longitudinal axis is located in the center of this one channel.

[0036] Preferably, all channels extend parallel to the central longitudinal axis.

[0037] Preferably, channels that do not extend along the central longitudinal axis of the support are arranged symmetrically and evenly spaced around the central longitudinal axis of the support in order to maximize the strength of the catalyst obtained.

[0038] The shape of the channel is not further limited, but the channel may have, for example, a circular, elliptical, teardrop, or polygonal cross-section.

[0039] The cross-sectional area of ​​the channel is preferably 0.3 mm². 2 ~15mm 2 The range, especially 1.0 mm 2 ~10mm 2 This is within the range. At least three channels may all have the same cross-sectional area. It may be advantageous if one channel extending along the central longitudinal axis of the carrier has a larger cross-sectional area than at least two other channels.

[0040] Advantageously, the ratio of the channel cross-sectional area to the total cross-sectional area of ​​the carrier is at least 10%, particularly at least 15%, and particularly advantageously at least 20%.

[0041] If the channel has a circular cross-sectional area, the diameter of the channel is preferably in the range of 0.1 mm to 4 mm, preferably in the range of 0.5 mm to 3 mm, and particularly in the range of 1.0 mm to 2 mm. At least three channels may all have the same diameter. It may be advantageous if one channel extending along the central longitudinal axis of the carrier has a larger diameter than at least two other channels.

[0042] Advantageously, the volume percentage of the channels in the total volume surrounded by the support is at least 20%, particularly at least 25%, and particularly advantageously at least 30%. A high volume percentage of channels has a favorable effect on the volume expansion of the reaction gas during ammonia decomposition. Furthermore, the proportion of the geometric surface of the support increases, which may have a positive effect on the available catalyst surface.

[0043] The carrier may have flat or curved end faces. In an advantageous embodiment, the carrier may have at least one curved end face, and particularly advantageously, both end faces may be curved. Such curved end faces have been shown to increase the geometric surface area of ​​the carrier and have a positive effect on pressure loss in the reactor.

[0044] To achieve the longest possible service life of the carrier, it must have sufficiently high strength. This can be achieved, on the one hand, by the shape of the carrier, and on the other hand, by the strength of the material forming the carrier. Advantageously, the carrier has a lateral fracture hardness of over 30 N, preferably over 50 N. Lateral fracture hardness can be measured according to the method described later.

[0045] Advantageously, the carrier has abrasion resistance of less than 30%, more preferably less than 20%. Abrasion resistance can be measured using the method described later.

[0046] The thermal expansion coefficient of the carrier is advantageously 10*10 -6 K -1 Less than 8*10 -6 K -1 It is less than.

[0047] The supported catalyst contains ruthenium, which means that the supporting material of the carrier is contaminated with at least ruthenium. Therefore, ruthenium forms at least a portion of the catalytically active component of the supported catalyst.

[0048] As used herein, the term “ruthenium” does not include information regarding the oxidation state of ruthenium. In other words, it does not indicate the existence of an elemental state having an oxidation state of (0). Ruthenium may exist on and / or on the supporting material in elemental form, i.e., in an oxidation state of (0) and / or higher oxidation states. As used herein and known to those skilled in the art, the term “oxidation state” means the formal charge of an atom in a compound or the actual charge of a monatomic ion. An atom in an elemental state has, by definition, an oxidation state of (0).

[0049] A supported material being ruthenium-constituted means that ruthenium is supported on the supported material of the carrier; that is, ruthenium is present on, in, and / or within the supported material, for example, in the form of particles and / or layers. The terms “constituted” and “supported” are used synonymously and interchangeably in this application. The supported material may be constituted both on its surface and internally. The term “surface” includes both the outer surface and the inner surface, i.e., the inner surface formed by pores.

[0050] Typically, the support is conjugated with 0.01 wt.% to 20 wt.%, preferably 0.1 wt.% to 15 wt.%, more preferably 0.5 wt.% to 10 wt.%, and particularly preferably 1.0 wt.% to 5 wt.%, of ruthenium based on the total amount of supported catalyst.

[0051] For the purposes of this application, where a range is mentioned, the range limits are deemed to be included.

[0052] The supported catalyst preferably contains 20 wt.% or less of ruthenium, more preferably 15 wt.% or less, and more preferably 10 wt.% or less.

[0053] For example, the supported catalyst contains 20 wt.% ruthenium, 15 wt.% ruthenium, 12 wt.% ruthenium, 10 wt.% ruthenium, 9 wt.% ruthenium, 8 wt.% ruthenium, 7 wt.% ruthenium, 6 wt.% ruthenium, 5 wt.% ruthenium, 4 wt.% ruthenium, 3 wt.% ruthenium, 2 wt.% ruthenium, 1 wt.% ruthenium, 0.5 wt.% ruthenium, 0.1 wt.% ruthenium, 0.05 wt.% ruthenium, 0.01 wt.% ruthenium, or intermediates thereof.

[0054] The supporting material of the supported catalyst is conjugated with at least ruthenium as a catalytically active component. However, the supporting material may be conjugated with additional components, such as at least one other precious metal, or accelerators such as transition metals, alkali metals, or alkaline earth metals.

[0055] In the following, the catalytically active components of a supported catalyst are referred to as a noble metal species, regardless of whether they contain ruthenium alone or ruthenium and at least one other noble metal. The terms “noble metal” or “noble metal species” as used herein do not include information regarding the oxidation state of the noble metal. In other words, they do not necessarily indicate the existence of an elemental state having an oxidation state of (0). Noble metal species may exist in and on the supported catalyst in elemental form, i.e., oxidation state (0) and / or higher oxidation states.

[0056] In one embodiment, the supported catalyst contains only one additional precious metal as a catalytically active component. In further embodiments, the supported catalyst contains two or more additional precious metals.

[0057] The at least one additional noble metal provided to the supported catalyst is preferably selected from Groups 8, 9, 10, or 11 of the periodic table. Particularly preferably, the at least one additional noble metal is selected from the group consisting of rhodium (Rh), palladium (Pd), silver (Ag), platinum (Pt), gold (Au), iridium (Ir), and combinations thereof. Platinum (Pt), palladium (Pd), rhodium (Rh), iridium (Ir), or combinations thereof are particularly preferred, and more preferred are platinum (Pt), iridium (Ir), and combinations thereof.

[0058] In particular, it has been found to be advantageous when the support material is provided with a combination of ruthenium and platinum, ruthenium and palladium, ruthenium, platinum and iridium, ruthenium, palladium and iridium, or ruthenium, palladium and platinum. In a particularly preferred embodiment, the support material is provided with ruthenium and iridium, or ruthenium, platinum and iridium.

[0059] When the support material is provided with at least one other noble metal, ruthenium and the at least one other noble metal are preferably present in a molar ratio ranging from 1:20 to 20:1, particularly in a ratio from 1:10 to 10:1.

[0060] The supported catalyst may contain noble metal species in the range of 0.01 wt.% to 20 wt.% based on the total weight of the supported catalyst. This refers to the sum of the proportions of all contained noble metal species, that is, the sum of all weight percentages of ruthenium and other optionally present noble metals. In a preferred embodiment, the weight fraction of noble metal species is 0.05 wt.% to 15 wt.%, particularly preferably 0.1 wt.% to 12 wt.%, most preferably 0.1 wt.% to 10 wt.%.

[0061] The supported catalyst may have a 0.1 m 2 / g to 200 m 2 / g CO surface area in this range. The CO surface is a measure of the surface area of noble metal species. The CO surface can be measured using the CO adsorption method described hereinafter. The supported catalyst has a 1 m2 / g~150m 2 / g range, more preferably 5m 2 / g~100m 2 The CO surface area may be in the range of / g. The CO surface area of ​​the supported catalyst is preferably at least 0.1m². 2 / g, more preferably at least 1m 2 / g, more preferably at least 5m 2 It could be / g

[0062] The precious metal species may be in particulate form. In this case, the particles may be present on and / or within the supporting material. "Present within the supporting material" means that the precious metal species may be present within the pores of the supporting material.

[0063] In principle, it is advantageous for precious metal particles to be as small as possible because the particles have a high degree of dispersion. The degree of dispersion is understood as the ratio of the number of precious metal atoms forming the surface of the precious metal particles to the total number of precious metal atoms in the precious metal particles. In preferred embodiments, the average particle size of the precious metal species is in the range of 0.1 nm to 15 nm, more preferably in the range of 1 nm to 10 nm, and particularly preferably in the range of 2 nm to 8 nm. It may be preferable for the particles of the precious metal species to have an average size of less than 15 nm, more preferably less than 10 nm. The average particle size of the precious metal species can be measured by transmission electron microscopy (TEM), as described later.

[0064] Preferably, the particles of the noble metal species are uniformly distributed on and / or within the support material, i.e., the distances between the particles are similar. Preferably, the average distance between the particles of the noble metal species on the support material, as measured by TEM, is at least 50%, more preferably at least 75%, of the average particle size.

[0065] The supported catalyst may be further enriched with non-precious metal components, preferably alkali metal or alkaline earth metal components, such as sodium, potassium, rubidium, cesium, magnesium, calcium, strontium, barium, or mixtures thereof. The terms “alkali metal” or “alkaline earth metal” as used herein do not include information regarding the oxidation state of the non-precious metal components. In other words, this does not indicate the presence of an elemental state having an oxidation state of (0). Non-precious metal components may exist in and on the supported catalyst in elemental form, i.e., oxidation state (0) and / or higher oxidation states. The proportion of these further non-precious metal components in the supported catalyst is preferably 1 wt.% to 25 wt.%, particularly 5 wt.% to 20 wt.%, and especially preferably 10 wt.% to 15 wt.% relative to the total weight of the supported catalyst.

[0066] When the supporting material is contaminated with a non-precious metal component, the ruthenium and the non-precious metal component are preferably present in a molar ratio in the range of 1:1 to 1:15, particularly in a ratio of 1:1 to 1:10, and especially preferably in a ratio of 1:2 to 1:5.

[0067] Particularly advantageous is that the supported catalyst is conjugated with at least one alkali metal component or alkaline earth metal component, for example, in an amount of 1 wt.% to 25 wt.%, preferably 2 wt.% to 20 wt.%, and more preferably 3 wt.% to 15 wt.% relative to the total weight of the supported catalyst. When the supported material is conjugated with an alkali metal component or alkaline earth metal component, ruthenium and the alkali metal component or alkaline earth metal component are present in a molar ratio preferably in the range of 1:1 to 1:15, particularly in a ratio of 1:1 to 1:10, and especially preferably in a ratio of 1:2 to 1:5. The conjugation of an alkali metal component or alkaline earth metal component has been found to be particularly advantageous for the activity of the supported catalyst.

[0068] In particular, the addition of barium has been found to be especially advantageous for the activity of the supported catalyst. Advantageously, the supported material is conjugated with 1 wt.% to 25 wt.% of barium relative to the total weight of the supported catalyst, preferably 2 wt.% to 20 wt.% and more preferably 3 wt.% to 15 wt.%. It has been found to be particularly advantageous when the supported catalyst is conjugated with barium and the molar ratio of ruthenium to barium is in the range of 1:1 to 1:15, particularly 1:1 to 1:10, and especially preferably 1:2 to 1:5.

[0069] The supported catalyst preferably contains a halogen content of less than 1000 ppm by mass, more preferably less than 500 ppm by mass, and most preferably less than 100 ppm by mass. Low halogen content has beneficial effects on the corrosion resistance of the supported catalyst itself and on the reactor system in which the supported catalyst is used. Catalysts with the lowest halogen content have been found to be particularly advantageous for the conversion of ammonia-containing gases, as this avoids the formation of ammonia and / or ammonium-containing halide salts, preventing these salts from being harmful to the reactor system.

[0070] The supported catalyst is 1 m 2 / g~1500m 2 A range of / g, preferably 10m 2 / g~1000m 2 A range of / g, particularly preferably 50m 2 / g~500m 2 It can have a BET surface area in the range of / g. The BET surface area, also called the specific surface area, can be measured using nitrogen as the adsorbate, according to ISO 9277:2010. In a preferred embodiment, the supported catalyst is 1500m 2 Less than 1000mg / g, preferably 1000mg 2 Less than / g, particularly preferably 500m 2 It has a BET surface area of ​​less than / g.

[0071] The supported catalyst may be porous, meaning that the supported catalyst may have micropores and / or mesopores and / or macropores. In the context of this invention, micropores are understood to mean pores having a diameter in the range of less than 2 nm, mesopores are understood to mean pores having a diameter in the range of 2 nm to 50 nm, and macropores are understood to mean pores having a diameter in the range of 50 nm to 5 μm. Pore diameter refers to the average diameter of the pores. Therefore, pore volume is understood to mean the sum of the volumes of such pores. The pore diameter distribution and pore volume can be measured by mercury porosimetry in accordance with ISO 15901-1:2016.

[0072] It is preferable that the supported catalyst has hierarchical porosity, that is, that the supported catalyst contains pores of different size ranges. Preferably, the supported catalyst contains macropores and mesopores.

[0073] Preferably, the supported catalyst contains macropores having a diameter greater than 100 nm, more preferably greater than 300 nm, and even more preferably greater than 500 nm. Preferably, the diameter of the macropores of the supported catalyst is uniform, that is, at least 75%, more preferably at least 85%, of the macropores have a diameter within 40% of the average diameter.

[0074] Preferably, the supported catalyst comprises mesopores having a diameter greater than 5 nm, more preferably greater than 15 nm, and even more preferably greater than 25 nm. Preferably, the diameter of the mesopores of the supported catalyst is uniform, that is, at least 75%, more preferably at least 85%, of the macropores have a diameter within 40% of the average diameter.

[0075] The total pore volume is preferably 0.3 cm³. 3 / g~2.5cm 3 Range of / g, especially 0.5cm 3 / g~1.5cm 3 It is within the range of / g.

[0076] The support of the present invention contains a refractory oxide as the supporting material. As used herein, the term "refractory oxide" refers to a metal-containing oxide that is chemically and physically stable at high temperatures, particularly under typical operating temperatures and conditions in reactors. Refractory oxides are often also called heat-resistant oxides.

[0077] The refractory oxide may be an oxide of a transition metal or a main group metal, for example, an oxide of a group 3 metal, a group 13 metal, a group 4 metal, a group 14 metal, a group 5 metal, or a combination of two or more of the aforementioned metal oxides. The refractory oxide can be selected from the group consisting of titanium oxide (e.g., TiO2), zirconium oxide (e.g., ZrO2), niobium oxide (e.g., Nb2O5), tantalum oxide (e.g., Ta2O5), cerium oxide (e.g., CeO2), aluminum oxide (e.g., α- or γ-Al2O3), SiO2, BeO, MgO, CaO, SrO, BaO, ZnO, Y2O3, La2O3, SnO2, CdO, PbO, As2O3, Bi2O3, Sb2O5, V2O5, Cr2O3, MoO3, WO3, and a mixture of two or more of the aforementioned metal oxides.

[0078] Preferably, the refractory oxides include aluminum oxide, magnesium oxide, silicon oxide, molybdenum oxide, tungsten oxide, titanium oxide, zirconium oxide, mixed oxides or composite oxides of two or more of these, particularly preferably aluminum oxide or mixed oxides or composite oxides of aluminum oxide, preferably α- or γ-Al2O3. As used herein, the term “mixed oxide” refers, on the one hand, to a mixture of single-phase oxides, as is generally known in the art. These are also called “solid solutions” having a uniform crystal lattice in which the individual metal oxides can no longer be distinguished. As used herein, the term is also used to include physical mixtures of oxides that include metal oxide aggregates that do not have a uniform crystal lattice, in which the phases of the individual metal oxides can be distinguished. As used herein, the term “composite oxide” generally refers to a composition of oxides having two or more phases, as is generally known in the art.

[0079] Preferably, the supported catalyst contains a refractory oxide in an amount of at least 60 wt.%, more preferably at least 70 wt.%, even more preferably at least 80 wt.%, particularly preferably at least 85 wt.%, and most preferably at least 90 wt.%, relative to the total weight of the supported catalyst.

[0080] Refractory oxides can be doped, in other words, refractory oxides can contain dopants. Dopant-doped supported materials can be obtained using methods known in the relevant art. Doping can improve the heat resistance of the supported material, suppress aggregation of catalytically active components, and / or increase the activity and stability of the supported catalyst.

[0081] Suitable dopants can be selected from the group consisting of rare earth metals, transition metals, alkali metals, alkaline earth metals, and mixtures thereof. In particular, dopants may contain at least one element selected from the group consisting of sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), magnesium (Mg), calcium (Ca), cerium (Ce), zirconium (Zr), titanium (Ti), silicon (Si), manganese (Mn), yttrium (Y), lanthanum (La), barium (Ba), praseodymium (Pr), gadolinium (Gd), samarium (Sm), neodymium (Nd), scandium (Sc), tantalum (Ta), oxides thereof, and mixtures of two or more of the above. Preferably, the dopant contains barium, calcium, and / or potassium.

[0082] Particularly preferred are doped refractory oxides such as aluminum oxide doped with barium, barium oxide, calcium, calcium oxide, potassium and / or potassium oxide, mixed oxides of aluminum oxide doped with barium, barium oxide, calcium, calcium oxide, potassium and / or potassium oxide, or composite oxides of aluminum oxide doped with barium, barium oxide, calcium, calcium oxide, potassium and / or potassium oxide.

[0083] In preferred embodiments, the refractory oxide comprises alkali metals and / or alkaline earth metals. The alkali metals or alkaline earth metals may exist as components imparted to the refractory oxide and / or as dopants to the refractory oxide. In particular, the supporting material comprises barium, calcium and / or potassium.

[0084] The supported catalyst may include Al2O3 as a refractory oxide, at least ruthenium as a catalytically active component, and platinum (Pt), palladium (Pd), rhodium (Rh), iridium (Ir), magnesium (Mg), calcium (Ca), strontium (Sr), and / or barium (Ba) as further components. Examples of preferred embodiments of the supported catalyst are Ru / Al2O3, Ru+Pt / Al2O3, Ru+Pd / Al2O3, Ru+Rh / Al2O3, Ru+Ir / Al2O3, Ru+Mg / Al2O3, Ru+Ca / Al2O3, Ru+Sr / Al2O3, or Ru+Ba / Al2O3.

[0085] In particularly preferred embodiments, the supported catalyst comprises aluminum oxide, especially γ-Al2O3, as a refractory oxide, and 0.01 wt.% to 20 wt.% of ruthenium. In these cases, the supported catalyst is 10 m 2 / g~400m 2 Range of / g, preferably 20m 2 / g~300m 2 It may be preferable to have a BET surface area in the range of / g. In a preferred embodiment, when aluminum oxide is used as the supporting material, the supported catalyst is 400m 2 Less than 300mg / g, preferably 300mg 2 Less than / g, particularly preferably 200m 2 It has a BET surface area of ​​less than / g.

[0086] In even more preferred embodiments, the supported catalyst comprises aluminum oxide, particularly γ-Al2O3, as a refractory oxide, 0.01 wt.% to 20 wt.% of ruthenium, and 1.0 wt.% to 10.0 wt.% of barium. In these cases, the supported catalyst is 10 m2 / g~400m 2 Range of / g, preferably 20m 2 / g~300m 2 It may be preferable to have a BET surface area in the range of / g. In a preferred embodiment, when aluminum oxide is used as the supporting material, the supported catalyst is 400m 2 Less than 300mg / g, preferably 300mg 2 Less than / g, particularly preferably 200m 2 It has a BET surface area of ​​less than / g.

[0087] Methods for producing ruthenium-conjugated carriers are known to those skilled in the art. Typically, a composition containing at least a refractory oxide is provided, which is formed into a desired shape, for example, by extrusion, pressing, granulation, or casting. In addition to the refractory oxide, the composition may also contain other components such as solvents or binders.

[0088] In such a method, the refractory oxide is preferably provided in powder form. A suitable method for producing a ruthenium-conjugated support may include a further step, for example, heating the molded powdered refractory oxide.

[0089] If the refractory oxide is already impregnated with at least ruthenium during the molding process, a uniformly ruthenium-impregnated support is obtained. Uniform impregnation means that ruthenium is distributed almost uniformly throughout the internal and external regions of the support.

[0090] If ruthenium is not impregnated during the molding of the refractory oxide, a ruthenium-free support is initially obtained, which is then impregnated with at least ruthenium in a further process. In such a manufacturing method, the ruthenium is not uniformly distributed within the support. It has been found that this non-uniform distribution of ruthenium within the support is advantageous. In other words, it is advantageous if the supported catalyst is a shell catalyst in which the ruthenium is mainly located in the edge regions of the support. Such a shell catalyst allows for the most efficient utilization of the precious metal used.

[0091] Advantageously, the thickness of the margin region is less than 1000 μm, preferably less than 700 μm, and particularly less than 500 μm. The thickness of the margin region can be measured by combining SEM and EDX measurements, as described later. In the context of the present invention, the margin region of the supported catalyst is understood to mean both the margin region of the surrounding surface and the margin region within the channel.

[0092] Preferably, at least 60 wt.% of ruthenium is present in the outer 40 vol.% region of the supported catalyst, and more preferably at least 70 wt.% relative to the total amount of ruthenium.

[0093] Ruthenium can be impregnated into a support material using methods known to those skilled in the art, such as impregnation, precipitation, chemical vapor deposition (CVD), coating, or spraying. The impregnation can be carried out in one or more steps.

[0094] The impregnation typically involves contacting a supported material with a ruthenium precursor compound, which is usually provided in a composition containing at least one solvent. After combining these, the ruthenium precursor compound can be precipitated and / or reduced, and then dried and / or calcined. Preferably, the supported catalyst is obtained by impregnating a supported material with the composition and then reducing it. Optionally, heat treatment may be performed before or after reduction.

[0095] The support material can be added in this manner before molding, or when the support material is already available as a molded body. In the first case, for example, the support material can be added in powder form first, and then molded, for example, by extrusion or pressing. In such a case, the ruthenium is uniformly distributed in the molded body.

[0096] Various impregnation processes are known to those skilled in the art, including, for example, capillary-controlled impregnation (the so-called "initial wetting" method) and diffusion-controlled impregnation (the so-called "adsorption-controlled" method). In principle, either approach is suitable for producing supported catalysts suitable for the present invention. Impregnation is generally understood to mean bringing a support material and a compound together, and as a result the compound being adsorbed onto the surface of the support material. In the case of porous support materials, this is particularly the inner surface, i.e., the surface within the pores.

[0097] This combination is achieved, for example, by adding the composition to a solvent suspension of the support material and mixing the mixture. However, it is also possible to spray such a composition onto the support material, or to add the support material to such a composition and then mix the mixture. Methods for mixing such systems, such as stirring, are known to those skilled in the art and may be used, including forced mixers, free-fall mixers, stirrers, flow mixers, or mixing pumps.

[0098] Supported catalysts are, for example, I) A step of impregnating a support material with a composition containing a ruthenium precursor compound and a solvent, II) It can be manufactured by a method including a reduction step.

[0099] The impregnated (i.e., supported with the ruthenium precursor compound) support material is obtained as a result of impregnation step I). Preferably, a homogeneous or uniform coating of the support material with the ruthenium precursor compound is achieved.

[0100] In this case, "solvent" means that the solvent contains at least one liquid substance in which the ruthenium precursor compound is soluble. The at least one solvent may contain multiple chemical substances; that is, the solvent may be a mixture of solvents.

[0101] At least one solvent can be selected from the group consisting of water and organic solvents. The organic solvent can be selected from several commercially available organic solvents. The organic solvent is conveniently substantially volatile under the processing conditions of the composition. The organic solvent may be, for example, an alcohol such as methanol or ethanol. Preferably, the organic solvent consists of at least 60 vol.%, more preferably at least 70 vol.%, and especially at least 80 vol.%, of water. It may be advantageous for the solvent to consist entirely of water.

[0102] In preferred embodiments, the composition contains 20 wt.% to 99.5 wt.% of the solvent, preferably 30 wt.% to 95 wt.% of the total weight of the composition. Advantageously, the composition contains at least 50 wt.%, particularly preferably at least 80 wt.%, and very particularly preferably at least 90 wt.% of the solvent.

[0103] The amount of ruthenium in the composition can vary widely and is determined by the intended filling amount of the ruthenium-containing support material. “Amount of ruthenium” refers to the proportion of ruthenium in the composition; in other words, it does not refer to the total amount of the ruthenium precursor compound. Preferably, the composition contains 0.5 wt.% to 75 wt.% of ruthenium relative to the total weight of the composition, which includes at least one solvent and the ruthenium compound. In one embodiment, the composition contains 1 wt.% to 60 wt.% of ruthenium, preferably 5 wt.% to 50 wt.%. Particularly good results are obtained when the composition contains at least 0.5 wt.%, particularly at least 1 wt.%, preferably at least 5 wt.%, and more preferably at least 10 wt.% of ruthenium.

[0104] Ruthenium precursor compounds are compounds of ruthenium that can be converted to an elemental state by thermal decomposition or wet chemical reduction. Suitable compounds include ruthenium salts, complexes, or organometallic compounds. Examples of suitable ruthenium compounds include ruthenium nitrate, ruthenium acetate, pentacarbonylruthenium, ruthenium acetylacetate, ruthenium oxalate, ruthenium nitrosyloxalate, ruthenocene, and ruthenium nitrosylnitrate.

[0105] The composition may contain only one ruthenium precursor compound, or it may contain several ruthenium precursor compounds.

[0106] The ruthenium precursor compound is preferably a halogen-free ruthenium compound, and more particularly a chloride-free ruthenium compound. A halogen-free, and especially chloride-free, ruthenium compound is understood to mean a ruthenium compound that does not contain halogen or chloride components, except for unavoidable impurities, such as residues arising from the manufacturing process. The manufacture of supported catalysts using precursor compounds containing halogens or chlorides requires cleaning the manufactured material, which makes the manufacturing process expensive and complex.

[0107] It has been found that the supported catalyst used in the method according to the present invention is advantageous when it is manufactured using an oxalate-containing ruthenium precursor compound, in other words, when the catalytically active ruthenium component supported on the support material is manufactured at least partially from such a precursor compound. Such supported catalysts have been found to have high long-term stability and, at the same time, require a short induction phase to achieve full activity. Furthermore, since complex washing steps can be omitted and no harmful decomposition products are generated, the supported catalysts are particularly advantageous in their manufacture.

[0108] Preferably, the ruthenium in the oxalate-containing ruthenium precursor compound can be converted to its elemental state via thermal decomposition or by wet chemical reduction. In particular, the ruthenium in the oxalate-containing ruthenium precursor compound can be converted to its elemental state by thermal decomposition under inert or reducing conditions. In other words, other oxidation states can also be achieved under non-reducing or non-inert conditions. Such ruthenium precursor compounds are advantageous in that, in addition to forming a catalytically active ruthenium component, they can be decomposed substantially without residue. For example, compared to carbonyl complexes of ruthenium, they also have the advantage of being less volatile and, as with the corresponding decomposition products, less toxic or even non-toxic.

[0109] The oxalate-containing ruthenium precursor compound is advantageously decomposable at temperatures below 500°C, particularly below 400°C, and especially preferably below 300°C.

[0110] Oxalate-containing ruthenium precursor compounds are compounds containing ruthenium in any oxidation state and at least one oxalate unit. Ruthenium can exist in a single or different oxidation state within the compound. The term "oxalate unit" refers to a non-complexing or ligand-active, i.e., complexing C2O4. 2 This refers to a dianion. Ruthenium precursor compounds can have one or more ruthenium centers.

[0111] An oxalate-containing ruthenium precursor compound may be a ruthenium-containing salt or ruthenium complex compound that contains, in addition to at least one oxalate ligand (Ox), at least one further ligand, such as a hydroxy ligand (OH), a carbonate ligand (CO3), a nitrosyl ligand (NO), an ammonia ligand (NH3), or a hydrate ligand (H2O), as well as other ligands that decompose without leaving any residue.

[0112] Examples of suitable ruthenium precursor compounds include ruthenium oxalate, ruthenium nitrosyloxalate, ruthenium carbonate, and their respective ammonium salts, hydrates, and acids.

[0113] The production of oxalate-containing ruthenium precursor compounds and their solutions is described, for example, in German Patent Publication No. 102007014914(A1) and German Patent Publication No. 1533088(A1). In appropriate production methods, isolated ruthenium precursor compounds can be used, and their solutions can also be used directly.

[0114] In a preferred embodiment, the support material is dispersed in the composition during the impregnation process. A suspension in the sense of the present invention is a mixture of a solid and a liquid, in which the solid is uniformly dispersed in the liquid in the form of a finely dispersed solid.

[0115] In an alternative embodiment, the support material and composition exist in the form of an impregnated powder during the impregnation process. This means that the solution is added only to the extent that the support material is wetted.

[0116] In a further embodiment, the supporting material is already in the form of a carrier, and the composition is added to such an extent that the pores of the carrier are completely filled.

[0117] The impregnation process can be carried out at room temperature. However, the impregnation process can also be carried out at temperatures lower or higher than room temperature. During the impregnation process, the temperature of the mixture containing the support material and the composition may be, for example, 10°C to 90°C, more preferably 20°C to 80°C. The duration of the impregnation process is selected so that a sufficient amount of the ruthenium precursor compound is deposited on the support material. A suitable duration can be determined by those skilled in the art based on routine experiments.

[0118] Preferably, the ruthenium precursor compound is completely separated from the solution onto the support material. Therefore, after the impregnation step, the solvent does not contain the ruthenium precursor compound.

[0119] When multiple components are to be imparted to a support material, it may be preferable to provide the compounds together in a single composition. However, it may also be preferable to provide these compounds in separate compositions. Both variations are suitable for simultaneously imparting, for example, ruthenium and iridium or ruthenium and barium to a support material.

[0120] In further embodiments, it may be advantageous to sequentially impart different components to the support material, i.e., to impart ruthenium first, followed by the imparting of further components, or vice versa, and the final reduction step can be carried out together for both species or as an intermediate step.

[0121] For example, aluminum oxide can be first coated with ruthenium, and then with barium. The barium is preferably applied to the aluminum oxide in a composition containing barium acetate.

[0122] However, it may also be advantageous to first impart barium to aluminum oxide, and then ruthenium. The barium may be applied to the aluminum oxide in this order, preferably in a composition containing barium acetate.

[0123] The amount of support material used during manufacturing depends on the desired amount of ruthenium deposited on the support material, and therefore also on the concentration of ruthenium in the composition of the ruthenium precursor compound used.

[0124] During the impregnation process, the supporting material is present in an amount ranging from 5 wt.% to 95 wt.% of the total amount of the composition and the supporting material, more preferably in an amount ranging from 10 wt.% to 90 wt.%.

[0125] The composition may also contain other components, such as acids.

[0126] Depending on the circumstances, this method may also include drying or heat treatment of the impregnated support material after step I) and before step II).

[0127] Preferably, at least 90% of the solvent is removed before the reduction step, and the impregnated support material may also be completely dried until it reaches a certain weight.

[0128] Such heat treatment is also known to those skilled in the art as firing. "Firing" will be understood to those skilled in the art as a heat treatment in which metal components are preferably fixed to the support material.

[0129] In a preferred embodiment, the ruthenium precursor compound is decomposed by heat treatment of the impregnated support material. The heat treatment is preferably carried out in the presence of oxygen. The heat treatment can be carried out at temperatures below 1000°C, below 900°C, below 800°C, below 700°C, below 600°C, below 500°C, below 400°C, or below 300°C. In one embodiment, the impregnated support material is heat-treated at a temperature of 350°C to 500°C. The heat treatment is preferably carried out for 0.5h to 24h, preferably 2h to 18h.

[0130] Firing can be carried out under atmospheric conditions and under inert gas conditions.

[0131] Drying and firing can also be carried out in a common process.

[0132] In step II) of the method for producing the supported catalyst, reduction is performed. This means that the ruthenium precursor compound present on the supported material after impregnation is converted, at least partially, to a lower oxidation state.

[0133] The reduction method and suitable reducing agents are, in principle, known to those skilled in the art. The reduction process can be carried out, for example, under a reducing atmosphere or by wet chemical means. In particular, the reduction process can be carried out under a forming gas atmosphere using reducing acids, their salts, or reducing boron compounds. Those skilled in the art understand that the forming gas is a gas mixture containing nitrogen and hydrogen, for example, 95 vol.% nitrogen and 5 vol.% hydrogen. In the case of wet chemical reduction, formic acid or a salt of formic acid, such as sodium formate, is preferably used as the reducing agent.

[0134] In the case of wet chemical reduction, the reduction step can be carried out directly in the impregnation solution; that is, the impregnated support material obtained after step I) is not separated from the solvent. In other words, it may be preferable to add the reducing agent immediately after step I).

[0135] The reduction process is carried out at a temperature of, for example, less than 700°C, more preferably less than 600°C, and particularly preferably less than 400°C. In the case of wet chemical reduction, it may be preferable to carry out the reduction at a temperature of less than 100°C. The reduction process is preferably carried out for 0.5 to 24 hours, more preferably 2 to 15 hours.

[0136] It may be preferable to use the material obtained in step II) in a further processing step.

[0137] In a preferred embodiment, the material obtained in step II) is filtered and dried. Drying is carried out at a temperature, for example, below 250°C, more preferably below 200°C, and even more preferably below 150°C. In particular, drying can be carried out under reduced pressure, preferably at a pressure of less than 300 mbar. Drying is preferably carried out in the absence of oxygen. Drying is preferably carried out for 0.5h to 30h, more preferably 2h to 24h.

[0138] After applying a powdered support material, the support material is subjected to further processing steps, such as pressing or extrusion, to obtain a ruthenium-containing support. Such methods for forming powdered support materials are known to those skilled in the art.

[0139] The method according to the present invention includes contacting a supported catalyst with an ammonia-containing gas.

[0140] Contact is preferably made at a pressure in the range of 1 bar to 300 bar, more preferably in the range of 10 bar to 200 bar.

[0141] Advantageously, the volume-based space velocity per hour ("gas hourly space velocity," GHSV) is 1,000 h -1 ~100,000h -1 The range, especially 1,500h -1 ~50,000h -1 range, particularly preferably 2,000h -1 ~10,000h -1 This is within the range. It may be advantageous to increase the residence time of ammonia-containing gas in the catalyst bed by reducing the amount of NH3 processed.

[0142] Since the reaction is endothermic, it may be advantageous to carry out the reaction at a high temperature. The temperature is preferably 300°C to 800°C, and particularly 400°C to 700°C. In particular, it may be advantageous to heat the supported catalyst or the supported catalyst bed to this temperature.

[0143] Depending on the supported catalyst used, this method can be carried out at lower temperatures, preferably below 600°C, especially below 500°C, and most preferably below 400°C.

[0144] The ammonia-containing gas can be preheated before the contact step. In a preferred embodiment, the ammonia-containing gas is preheated to at least 200°C, more preferably at least 400°C.

[0145] The method according to the present invention is preferably carried out in a reactor made of at least partially corrosion-resistant material, such as stainless steel.

[0146] The reactor may be a closed-loop reaction system, a flow reaction system, or a batch reaction system, with the flow reaction system being the most preferred from a practical standpoint.

[0147] The present invention further relates to the use of a ruthenium-containing supported catalyst in a method for producing hydrogen from an ammonia-containing gas by contacting the supported catalyst with the ammonia-containing gas, wherein the supported catalyst is provided in the form of a ruthenium-contaminated support, and the support is The supporting material contains a refractory oxide, It is cylindrical, and The invention relates to a catalyst support comprising at least three spaced channels extending completely through the support, one of which extends along the central longitudinal axis.

[0148] All descriptions made regarding the method of producing hydrogen from ammonia-containing gas also apply to the use of ruthenium-containing supported catalysts for this application. [Brief explanation of the drawing]

[0149] The present invention will be described in more detail with reference to the following figures. However, the present invention is not limited to these embodiments.

[0150] [Figure 1] Cross-sections of carriers having different numbers of channels, particularly suitable for the method according to the present invention, are shown. The carrier has an outer diameter DA. The channels are characterized by their inner diameter DK. The carrier in Figure 1A has three channels, the carrier in Figure 1B has four channels, and the carrier in Figure 1C has five channels, each having the same inner diameter. The carrier in Figure 1D has eight channels, and the inner diameter DK1 of the central channel is greater than the inner diameters DK2 of the seven non-central channels. [Figure 2] Figure 2A shows a side view of a carrier having length L and outer diameter DA. The dashed line indicates the position of the central longitudinal axis. The carrier in Figure 2A has a straight end face. The carrier in Figure 2B has a curved end face. [Figure 3]Figure 3 shows the pressure drop of a catalyst bed with a channeled support (IE1) compared to a support without channels (CE).

[0151] The measurement methods used in this invention are described in detail below. Where a test method is not specified, the parameters were identified using an appropriate ISO method valid as of the filing date of this application. Unless specific measurement conditions are indicated, measurements were performed at room temperature (298.15 K) and standard pressure (100 kPa).

[0152] Measurement method BET specific surface area The BET specific surface area was measured at 77K using nitrogen as the adsorbate, according to the BET theory (multi-point method, ISO9277:2010).

[0153] CO adsorption The noble metal surface area of ​​the catalyst was measured by CO adsorption. For this purpose, the catalyst was first reduced at 400°C for 20 minutes under a foaming gas mixture of 95% argon and 5% hydrogen in a sealed container. Subsequently, carbon monoxide (CO using helium as a support gas) was pulsed into the container containing the catalyst. This was continued until a constant CO peak was detected under the catalyst. The amount of CO absorbed by the catalyst was determined by measuring the peak area of ​​the administered CO and the peak area of ​​the converted CO. For this purpose, the integral of the area of ​​the converted CO was subtracted from the integral of the area of ​​the administered CO. From the amount of CO absorbed thus obtained, the amount of CO stored per unit volume of the catalytic active composition used was calculated. By conversion, the surface area of ​​the active noble metal center (often also called the CO surface or noble metal surface) could be measured from the measured amount of CO stored at the active center.

[0154] Pore ​​volume and pore size distribution Pore ​​volume and pore size distribution were measured by mercury porosimetry in accordance with ISO 15901-1:2016.

[0155] Determination of precious metal content by ICP-OES The precious metal content was measured by inductively coupled plasma-optical emission spectroscopy (ICP-OES). First, 500 mg of the sample was dissolved in 25 mL of HF+HCl. Then, the solution was filled with water to 250 mL.

[0156] SEM-EDX Characterization The distribution of ruthenium in the support material was characterized using scanning electron microscopy (SEM) images combined with EDX spectroscopy (energy-dispersive X-ray spectroscopy). For sample preparation, coated support materials were embedded in resin, cut, and polished. These analyses were performed using a Jeol JSM-IT100 scanning electron microscope equipped with an integrated energy-dispersive X-ray analysis system using a 20 keV electron beam.

[0157] pressure loss The pressure drops of different catalyst beds were measured using a PTB-100 (Bastra Engineering) system. The system was first calibrated in an empty state. Then, molded catalyst material was packed into a tubular sample holder (150 mm in diameter) (filling height 50 mm). A pressure sensor was used to determine the pressure difference as the flow velocity gradually increased. Evaluation was performed using the system's own software.

[0158] Lateral fracture hardness of catalyst support To measure lateral fracture hardness, the support material was loaded between two parallel plates while increasing the force until fracture occurred. The force recorded at fracture corresponds to the lateral fracture hardness.

[0159] Sample preparation was performed by drying overnight at 150°C under vacuum, followed by cooling. Measurements were performed using a tablet hardness tester (ERWEKA TBH 325 model). Measurements were performed under a constant force increase of 20 N / s.

[0160] Wear resistance Abrasion resistance was measured by mechanical load in a rotating steel cylinder in the presence of additional steel balls. Sample preparation was performed by pre-sieving the material, then drying it overnight at 120°C under a nitrogen atmosphere, and finally cooling it. The properly prepared material was weighed into a steel cylinder, and then the material was rotated around the axis of the steel cylinder itself at 80 revolutions / min for 30 minutes. The resulting abrasive was sieved and weighed (A). Abrasion is expressed as a percentage of the original weight of the material (M0). Wear [%] = A * M0 -1 *100.

[0161] Testing catalytic activity The manufactured catalyst was tested in a fixed-bed test rig consisting of a reactor with a heatable quartz glass tube.

[0162] Before execution, the catalyst support was placed on a test bench and activated at 550°C under hydrogen. After activation, the catalyst material was heated to the respective reaction temperature in a nitrogen stream (100 mL / min). After a 10-minute tempering step, a gas mixture (NH3-N2 mixture in a 9:1 ratio) was introduced onto the catalyst material. The gas sample was collected at the reactor outlet using an airtight syringe, and the nitrogen-hydrogen ratio was measured by gas chromatography.

[0163] The present invention will be described in more detail with reference to the following examples. However, these examples should not be understood as limiting.

[0164] For the comparative example (CE), the diameter was 2.5 mm and the BET surface area was 215 m². 2 γ-Al2O3 spheres with a concentration of 0.8 mL / g and a pore volume of 0.8 mL / g were used. The spheres were first pre-treated with NaOH solution and then dried.

[0165] For the embodiment (IE) of the present invention, a γ-Al2O3 cylinder having an outer diameter of 12 mm and seven channels, each having an inner diameter of 2 mm, were used, and these were similarly pretreated with NaOH. The BET surface area of ​​the carrier was 105 m². 2 The pore volume was 0.6 mL / g.

[0166] The ruthenium filler content was 1.5 wt.% in all examples.

[0167] CE-(Ru / Al2O3 containing RuCl3) Pre-treated Al2O3 spheres were treated with a Ru chloride (RuCl3) solution and dried (70°C for 30 min). For firing, the dried material was treated in a 450°C oven for 4 hours. The Ru-coated Al2O3 was washed under running water for 4 days. Finally, the material was dried and reduced in a 250°C oven under a foaming gas for 16 hours.

[0168] IE1 (Ru / Al2O3 including RuCl3) Ruthenium was added to the pre-treated Al2O3 cylinder in the same manner as with CE.

[0169] IE2 (Ru / Al2O3 containing nitrosyloxalate Ru) The pre-treated Al2O3 cylinders were impregnated with a solution of nitrosyl oxalate Ru and dried (at 70°C for 30 min). For firing, the pre-dried material was treated in a 450°C oven for 4 hours. Finally, the material was reduced in a 250°C oven under a foaming gas for 16 hours.

[0170] IE3 (Ru / Al2O3 containing oxalic acid Ru) The pre-treated Al2O3 cylinder was impregnated with oxalic acid Ru solution and dried (at 70°C for 30 min). Calcination and reduction were carried out in the same manner as in IE2.

[0171] Figure 3 shows the pressure drop of a catalyst bed with a channeled support (IE1) compared to a support without channels (CE). The spherical solid sphere produces a significantly higher pressure drop than a support with a central channel and six other channels arranged around it, which negatively impacts the efficiency of reactors with such catalyst beds.

Claims

1. A method for producing hydrogen from ammonia-containing gas, i) A step of providing a supported catalyst in the form of a ruthenium-conjugated support, The carrier The supporting material contains a refractory oxide, It is cylindrical, and The process includes providing at least three spaced channels that extend completely through the carrier, one of which extends along the central longitudinal axis, ii) A method comprising the step of contacting the supported catalyst with the ammonia-containing gas.

2. The method according to claim 1, wherein the ammonia-containing gas contains at least 70 vol.% ammonia.

3. The method according to claim 1 or 2, wherein the carrier comprises 3 to 10 channels.

4. The method according to any one of claims 1 to 3, wherein the carrier has a length and / or outer diameter in the range of 0.5 mm to 50 mm.

5. The cross-sectional area of ​​the channel is 0.3 mm ２ ~15mm ２ The method according to any one of claims 1 to 4, which is within the range of claims 1 to 4.

6. The method according to any one of claims 1 to 5, wherein the ratio of the channel cross-sectional area to the total cross-sectional area of ​​the carrier is at least 10%.

7. The method according to any one of claims 1 to 6, wherein the carrier comprises at least one curved end face.

8. The method according to any one of claims 1 to 7, wherein the supported catalyst is coated with 20 wt.% or less of ruthenium.

9. The method according to any one of claims 1 to 8, wherein the supported catalyst is provided with at least one alkali metal or alkaline earth metal.

10. The method according to claim 9, wherein ruthenium and an alkali metal or alkaline earth metal are present in a molar ratio in the range of 1:1 to 1:

15.

11. The method according to any one of claims 1 to 10, wherein the refractory oxide is selected from the group consisting of aluminum oxide, magnesium oxide, silicon oxide, molybdenum oxide, tungsten oxide, titanium oxide, zirconium oxide, and two or more combinations of the aforementioned metal oxides, mixed oxides, and composite oxides.

12. The method according to any one of claims 1 to 11, wherein the supported catalyst is a shell catalyst.

13. The method according to claim 12, wherein the shell catalyst includes an edge region having a thickness of less than 1000 μm.

14. The method according to any one of claims 1 to 13, wherein the contact is performed at a pressure in the range of 1 bar to 300 bar.

15. A method for producing hydrogen from an ammonia-containing gas by contacting the supported catalyst with the ammonia-containing gas, wherein the supported catalyst is provided in the form of a ruthenium-contaminated support, The carrier The supporting material contains a refractory oxide, It is cylindrical, and The catalyst support comprises at least three spaced channels that extend completely through it, One of the aforementioned channels extends along the central longitudinal axis, for use.

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