Catalyst material for the dehydrogenation of hydrogen carrier materials

Abstract

A catalyst material for the dehydrogenation of hydrogen carrier materials comprises carrier material particles which have an oxidic material, silicon carbide and / or activated carbon, as well as mesopores and / or macropores, catalytically active material which is held on the carrier material particles, which comprises a metal and which has a proportion of at least 0.1 wt.% based on the catalyst material.

Description

[0001] The invention relates to a catalyst material for the dehydrogenation of hydrogen carrier material.

[0002] Liquid organic hydrogen carrier materials, also known as LOHCs, are known as hydrogen carrier materials. In catalytic hydrogenation and dehydrogenation processes, LOHCs can be loaded with hydrogen, which is chemically bound to the LOHC, and hydrogen can be released again. Hydrogenation and dehydrogenation are particularly reversible.

[0003] Supported precious metal catalysts, in particular supported platinum catalysts, are known from DE 10 2012 221 805 A1 for carrying out the dehydrogenation reaction.

[0004] It has been shown that the power density of a dehydrogenation reactor depends significantly on the volume-related productivity of the catalyst material. The productivity of the catalyst material, in turn, depends on the loading of the support material with the catalytically active material, particularly platinum. Loading is the ratio of catalytically active material to support material. Studies have shown that increasing the loading only leads to an increase in productivity within a certain range, in particular up to a so-called saturation value. In particular, excessive loading, especially when the saturation value is reached or exceeded, causes a loss of activity in the catalyst material. This is particularly disadvantageous for small-scale dehydrogenation reactors, which are particularly required in mobile applications. There is a need for dehydrogenation reactors with high power density.

[0005] The invention is based on the object of increasing the power density during the dehydrogenation of hydrogen carrier material.

[0006] This object is achieved according to the invention by a catalyst material having the features of claim 1.

[0007] The core of the invention is that a catalyst material comprises support material particles with mesopores and / or macropores. Mesopores have an average pore diameter between 2 nm and 50 nm, in particular between 10 nm and 40 nm. Macropores have an average pore diameter of at least 50 nm, in particular more than 100 nm, in particular at least 200 nm, in particular at least 500 nm, and in particular between 500 nm and 1,000 nm.

[0008] According to the invention, it was found that the support material particles enable higher volume-related productivity due to their improved pore structure. The support material particles have an increased pore volume. In particular, it was recognized that the mesopores enable improved mass transport of the LOHC and / or the released hydrogen gas. The mesopores generate an inner surface of the support material particles, which promotes a good distribution of catalytically active material. The macropores facilitate the transport and removal of the LOHC molecules. Furthermore, the macropores promote the nucleation and removal of hydrogen bubbles that form as a result of the hydrogen release during the dehydrogenation reaction.The catalyst material according to the invention makes it possible to increase the relative amount of catalytically active material on the support material particles compared to the prior art without resulting in a loss of activity. This means that with the catalyst material according to the invention, the loading of the support material particles with the catalytically active material can be increased without loss of activity, thereby enabling an increase in volume-related productivity. In particular, it has been recognized that a high pore volume in the region of the mesopores and / or the macropores makes it possible to increase the loading of the support material particles without loss of activity of the catalytically active material. This allows the volume-related productivity in hydrogen release to be increased. The proportion of catalytically active material is at least 0.1 wt. % based on the total weight of the catalyst material.

[0009] The support material particles comprise oxidic material, in particular aluminum oxide, silicon dioxide, titanium oxide, zirconium oxide, and / or cerium oxide. Additionally or alternatively, the support material particles may also comprise silicon carbide and / or activated carbon.

[0010] The catalytically active material comprises a metal, in particular a precious metal, especially platinum, palladium, nickel, rhodium, rhenium, and / or ruthenium. Mixtures and / or alloys of these elements are also possible. In particular, the catalytically active material consists of platinum. This means that no other catalytically active materials are present.

[0011] The catalytically active material is particularly deposited on the carrier material particles, i.e., it is held there in a material-to-material manner.

[0012] The hydrogen carrier material is in particular liquid and in particular organic. The hydrogen carrier material comprises cyclic hydrocarbons that are present in perhydrogenated and / or partially hydrogenated form. This means that the hydrocarbon compounds have no or only a small number of carbon-carbon multiple bonds. The cyclic hydrocarbons may contain heteroatoms, in particular nitrogen. In particular, the hydrocarbon compounds are oxygen-free. In particular, the perhydrogenated and / or partially hydrogenated hydrocarbons include methylcyclohexane and / or toluene, perhydrogenated and / or partially hydrogenated diphenylmethane, perhydrogenated and / or partially hydrogenated N-alkylated carbazole, in particular perhydrogenated and / or partially hydrogenated benzyltoluene and / or isomers thereof, and in particular perhydrogenated and / or partially hydrogenated dibenzyltoluene and / or isomers thereof.Benzyltoluene and / or dibenzyltoluene also include, in particular, isomers of the compounds mentioned as well as substituted benzyltoluenes and / or substituted dibenzyltoluenes in which one or both benzyl groups are substituted with one or more substitution groups, wherein the substitution groups include alkyl groups such as methyl groups or ethyl groups, aryl groups such as vinyl groups and / or heteroaryl groups such as pyridinyl groups.

[0013] Partially hydrogenated benzyltoluene includes benzyltoluene compounds in which at least one carbon-carbon double bond of the benzyltoluene is replaced by a carbon-carbon single bond. Perhydrogenated benzyltoluene includes benzyltoluene compounds in which the carbon-carbon double bonds are replaced by carbon-carbon single bonds. Examples of partially hydrogenated benzyltoluenes are 1-cyclohexylmethyl-2-methylbenzene, 1-cyclohexylmethyl-3-methylbenzene, 1-cyclohexylmethyl-4-methylbenzene, 1-benzyl-2-methylcyclohexane, 1-benzyl-3-methylcyclohexane, 1-benzyl-4-methylcyclohexane, and 1-(1,3-Cyclohexadienylmethyl)-4-methylbenzene.

[0014] Examples of perhydrogenated benzyltoluenes are 1-cyclohexylmethyl-2-methylcyclohexane, 1-cyclohexylmethyl-3-methylcyclohexane and 1-cyclohexylmethyl-4-methylcyclohexane.

[0015] A partially hydrogenated dibenzyltoluene includes any dibenzyltoluene compound in which at least one carbon-carbon double bond of the dibenzyltoluene is replaced by a carbon-carbon single bond. A perhydrogenated dibenzyltoluene includes any dibenzyltoluene compound in which all carbon-carbon double bonds are replaced by carbon-carbon single bonds.Examples of partially hydrogenated dibenzyltoluene are 1-benzyl-3-(cyclohexylmethyl)-5-methylbenzene, ((5-methyl-1,3-phenylene) to (methylene)dicyclohexane, 1-benzyl-4-(cyclohexylmethyl)-2-methylbenzene, ((2-methyl-1,4-phenylene) to (methylene)dicyclohexane, 2-benzyl-4-(cyclohexylmethyl)-1-methylbenzene, ((4-methyl-1,3-phenylene) to (methylene)dicyclohexane, 1-benzyl-3-(cyclohexylmethyl)-2-methylbenzene, ((2-methyl-1,3-phenylene) to (methylene)dicyclohexane, 1-benzyl-2-(cyclohexylmethyl)-4-methylbenzene ((4-methyl-1,2-phenylene) to (methylene)dicyclohexane 1-Benzyl-3-(1-cyclohexenylmethyl)-5-methylbenzene and 1-benzyl-3-(1,3-cyclohexadienylmethyl)-5-methylbenzene. Examples of perhydrogenated dibenzyltoluene are ((5-methylcyclohexane-1,3-diyl)bis(methylene)dicyclohexane), ((2-methylcyclohexane-1,4-diyl)bis(methylene)dicyclohexane), ((4-methylcyclohexane-1,3-diyl)bis(methylene)dicyclohexane), ((2-methylcyclohexane-1,3-diyl)bis(methylene)dicyclohexane, and ((4-methylcyclohexane-1,2-diyl)bis(methylene)dicyclohexane).

[0016] A partially hydrogenated N-alkylcarbazole, such as N-ethylcarbazole, includes any N-alkylcarbazole in which at least one carbon-carbon double bond therein is replaced by a carbon-carbon single bond. A perhydrogenated N-alkylcarbazole, such as N-ethylcarbazole, includes any N-alkylcarbazole in which all carbon-carbon double bonds therein are replaced by carbon-carbon single bonds. Examples of partially hydrogenated N-ethylcarbazole are 9-ethyl-2,3,4,9-tetrahydro-1H-carbazole, 9-ethyl-2,3,4,5,6,9-hexahydro-1H-carbazole, 9-ethyl-2,3,4,5,6,7,8,9-octahydro-1H-carbazole, and 9-ethyl-2,3,4,4a,5,6,7,8,9,9a-decahydro-1H-carbazole. Perhydrogenated N-ethylcarbazole, for example, is 9-ethyldodecahydro-1H-carbazole.

[0017] Dehydrogenation can be partial or complete. Dehydrogenation is preferably complete. Complete dehydrogenation occurs when fully saturated carbocyclyl or heterocyclyl residues (such as cyclohexyl or piperidinyl residues) or partially saturated carbocyclyl or heterocyclyl residues (such as cyclohexenyl or dihydropyridyl residues) are converted into the corresponding aromatic form (such as phenyl or pyridyl residues).

[0018] In a preferred embodiment, the dehydrogenation is carried out continuously in a reactor, in particular a fixed bed reactor, a fluidized bed reactor or a fluidized bed reactor.

[0019] A catalyst material according to claim 2 enables higher volume-related productivity. It has been found that increasing the proportion of the catalytically active material does not lead to a reduction in the activity of the catalyst material. The catalytically active material is advantageously arranged in the pore structure of the support material particles.

[0020] Catalyst materials according to claims 3 and 4 have advantageous pore volumes in various size classes. The mesopore volume is understood to be the pore volume of the mesopores. The macropore volume is understood to be the pore volume of the macropores.

[0021] The pore volume of the support material particles can be determined by analyzing the pore structure. Argon adsorption measurements at 87 K and / or mercury porosimetry measurements are particularly useful for determining the pore size distribution of the support material particles.

[0022] In particular, high-resolution gas adsorption measurements are performed using an automatic adsorption measuring device, specifically an Autosorb iQ from the manufacturer Quantachrome. Argon, purchased from AirLiquide under the designation Ar 6.0, serves as the adsorbent. Prior to the sorption measurements, the catalyst materials were degassed for at least twelve hours at 200°C under high vacuum.

[0023] Mercury intrusion and extrusion tests were conducted on the catalyst material using a Poremaster 60 measuring device manufactured by Quantachrome. The tests were conducted over a wide pressure range, particularly from vacuum up to 400 MPa.

[0024] The catalyst material according to claim 3 has proven to be particularly suitable for achieving higher catalyst loadings while maintaining the utilization of the catalytically active component.

[0025] The catalyst material according to claim 4 is particularly well suited for reliable transport and removal of the hydrogen carrier material.

[0026] A particularly advantageous volume-related productivity of the catalyst material is obtained when the mesopore volume is at least 0.17 cm 3 / g and the macropore volume at least 0.35 cm 3 / g.

[0027] A catalyst material according to claim 5 has a particularly advantageous activity.

[0028] A catalyst material according to claim 6 has proven to be particularly advantageous, in particular when the proportion of mesopores with a pore size of at most 25 nm is particularly large.

[0029] A catalyst material according to claim 7 has proven particularly advantageous for use in the dehydrogenation process. The support material particles have, in particular, a specific surface area of ​​at least 15 m 2 / g, in particular of at least 20 m 2 / g, in particular of at least 25 m 2 / g and especially in a range of 26 m 2 / g up to 81 m 2 / G.

[0030] The specific surface area is determined, in particular, by gas adsorption according to the Brunauer, Emmett, and Teller (BET) method, in accordance with DIN 66132. The specific surface area was determined using Ar physisorption with a dedicated measuring device. High-resolution gas adsorption measurements can be performed using an automatic adsorption measuring device, for example, the Autosorb iQ from Quantachrome. Argon at 87 K serves as the adsorbent, specifically Ar 6.0 from Air Liquide. Before the sorption measurements, the catalyst materials are degassed for twelve hours at 200 °C under high vacuum.

[0031] Mercury intrusion and mercury extrusion processes on the materials under investigation are carried out in a wide pressure range from vacuum up to 400 MPa using a measuring device called Poremaster 60 from the manufacturer Quantachrome.

[0032] In particular, the ratio of outer surface to volume of the carrier material particles is at least 1.0 mm -1 , especially 1.5 mm -1 , especially 1.75 mm -1 and in particular at least 1.79 mm -1 In principle, a geometry of the support material particles with the largest possible surface area to volume ratio has proven advantageous. Such particles result in increased catalyst activity.

[0033] A catalyst material according to claim 8 enables a high surface-to-volume ratio of the support material particles. The support material particles enable an increase in the power density of the catalyst material.

[0034] A catalyst material according to claim 9 is easy to produce. The support material particles are advantageously suitable for bed filling. The support material particles are shaped bodies. The shaped bodies can be in the form of an extrudate, in particular as strands or ribbed strands, in the form of tablets, rings, ring tablets, spheres, pellets, honeycombs, and / or granules, in particular in spherical form.

[0035] A catalyst material according to claim 10 simplifies the increase in loading. In particular, the catalytically active material can advantageously be applied to the support material particles. The average size of the nanoparticles is in particular at most 4 nm, in particular at most 3 nm, in particular at most 2.5 nm, in particular at most 2 nm, in particular at most 1.5 nm, in particular at most 1.0 nm, in particular between 1.0 nm and 1.5 nm, and in particular at least 0.5 nm.

[0036] Both the features specified in the patent claims and the features specified in the exemplary embodiments of catalyst materials according to the invention are suitable, either alone or in combination with one another, for further developing the subject matter of the invention. The respective combinations of features do not represent any limitation with regard to further developments of the subject matter of the invention, but are essentially merely exemplary in nature.

[0037] Further features, advantages, and details of the invention will become apparent from the following description of exemplary embodiments with reference to the drawings. They show: Fig. 1 a diagram showing the functional dependence of the volume-related productivity of different catalyst materials as a function of the loading with catalytically active material in the dehydrogenation of dibenzyltoluene, Fig. 2 a Fig. 1 corresponding diagram for different catalyst materials in the dehydrogenation of benzyltoluene, Fig. 3 a diagram showing the pore size distribution of the carrier material particles.

[0038] In a first example, different catalyst materials, and in particular their productivity in the dehydrogenation of dibenzyltoluene (H18-DBT) with a molar amount of 0.066 mol, are tested. Reference catalyst material 1 comprises aluminum oxide as the support material with an average particle size of 3.0 mm and a known pore structure. The total pore volume of reference catalyst material 1 is 0.52 cm3 3 / g. The mesopore volume is 0.17 cm 3 / g and the macropore volume is 0.35 cm 3 / g. Maxima of the pore size distribution are between 13 nm and 30 nm and between 120 nm and 800 nm. The specific surface area of ​​the reference catalyst material 1 is 26 m 2 / G.

[0039] In addition, two different catalyst materials 2, 3 according to the invention were tested, each having support material particles with an average particle size of 1.5 mm and 3.0 mm. Different loadings of catalytically active material in the form of platinum were tested for the different support material particles. In a batch experiment, the LOHC material H18-DBT was dehydrogenated at 310°C and 1.0 bar(a) and at a molar ratio of BT:H18-DBT = 1:2000.

[0040] The results are in Fig. 1. In the diagram, the volume-related productivity P v of the respective catalyst material depending on the loading B with the catalytically active material platinum.

[0041] As expected, volume-related productivity P vof the reference catalyst material 1 by about 11% when the platinum loading was doubled from 0.3 wt% to 0.6 wt%.

[0042] The comparable catalyst material 2 according to the invention, in which the support material particles have the same particle size of 3.0 mm, exhibits a volume-related productivity increased by over 50%. At a further loading to 0.9 wt.%, no significant loss of activity of the catalyst material 2 occurs.

[0043] The catalyst material 3 according to the invention, with support material particles having an average particle size of 1.5 mm, results in an additional productivity increase when the loading is increased to 0.9 wt.%. In this case, the volume-related productivity is more than double the initial value. The reason for this is that, due to the smaller support material particles, the external surface area relative to the volume of the support material particles is additionally increased.

[0044] Catalyst materials 1, 2, and 3 were also tested for the dehydrogenation of benzyltoluene (H12-BT). The test showed that the findings obtained for H18-DBT are essentially transferable to the dehydrogenation of H12-BT.

[0045] The catalyst material 2 according to the invention, with an identical particle size for the support material particles, enables higher volume-related productivity at a higher loading. The increase amounts to more than 30%.

[0046] The catalyst material 3 according to the invention with reduced particle size of the support material particles enables almost a tripling of the volume-related productivity of about 21 -1 min -1 with a platinum loading of 0.9 wt%.

[0047] In Fig. 3 is the pore size distribution d vd of the investigated catalyst materials 1, 2, 3 depending on the pore diameter d p For clarity, the pore diameter is plotted logarithmically.

[0048] It is over Fig.3 that the proportion of mesopores for the catalyst materials 2, 3 according to the invention is significantly larger than that for the reference catalyst material 1. The mesopore volume of the catalyst material 2 is 0.34 cm 3 / g and is thus twice as high as that of the reference catalyst material 1. The mesopore volume of the catalyst material 3 is 0.40 cm 3 / g and thus 2.35 times that of reference catalyst material 1.

[0049] This also applies to the macropores in a pore size range between 500 nm and 1,000 nm. The macropore volume of catalyst material 2 is 0.51 cm 3 / g and thus 1.46 times that of the reference catalyst material 1. The macropore volume of the catalyst material 3 is 0.47 cm 3 / g and thus 1.36 times that of reference catalyst material 1.

[0050] In contrast, macropores in the size range between 100 nm and 200 nm, which are particularly pronounced in the reference catalyst material 1, are essentially not present in the catalyst material 2, 3 according to the invention. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2012 221 805 A1

[0003]

Claims

[1] Catalyst material for the dehydrogenation of hydrogen carrier materials, wherein the catalyst material comprises a. Carrier material particles that exhibit i. an oxide material, silicon carbide and / or activated carbon, ii. Mesopores and / or macropores, b. catalytically active material that i. is held to the carrier material particles, ii. includes a metal, iii. has a proportion of at least 0.1 wt.% based on the catalyst material. [2] Catalyst material according to claim 1, characterized bythat the proportion of the catalytically active material is at least 0.15 wt.%, in particular at least 0.2 wt.%, in particular at least 0.25 wt.%, in particular at least 0.3 wt.%, in particular at least 0.4 wt.%, in particular at least 0.5 wt.%, 0.6 wt.%, in particular at least 0.9 wt.%, in particular at least 1.2 wt.%, in particular at least 1.5 wt.% and in particular at least 2.0 wt.% [3] Catalyst material according to any one of the preceding claims, characterized by that the carrier material particles have a mesopore volume of at least 0.10 cm³ 3 / g exhibit, in particular at least 0.12 cm 3 / g, in particular at least 0.15 cm 3 / g, in particular at least 0.17 cm 3 / g, in particular at least 0.20 cm 3 / g and in particular at least 0.25 cm 3 / G. [4] Catalyst material according to any one of the preceding claims, characterized bythat the carrier material particles have a macropore volume of at least 0.30 cm³ 3 exhibit / g, in particular at least 0.32 cm 3 / g, in particular at least 0.35 cm 3 / g, in particular at least 0.37 cm 3 / g, in particular at least 0.40 cm 3 / g and in particular at least 0.45 cm 3 / G. [5] Catalyst material according to any one of the preceding claims, characterized by , that the ratio of mesopore volume to macropore volume is greater than 0.5, in particular at least two-thirds, in particular at least 0.75, in particular at least 0.85 and in particular at least 1.

0. [6] Catalyst material according to any one of the preceding claims, characterized by, that the proportion of mesopores is at least 10% of the total pore volume, in particular at least 15% of the total pore volume and in particular at least 20% of the total pore volume, wherein in particular the proportion of mesopores with a pore size of at most 25 nm is at least 5% of the total pore volume, in particular at least 8% of the total pore volume and in particular at least 10% of the total pore volume. [7] Catalyst material according to any one of the preceding claims, characterized by that the carrier material particles are defined by a ratio of outer surface area to volume, where the ratio is at least 0.5 mm -1 amounts. [8] Catalyst material according to any one of the preceding claims, characterized bythat the carrier material particles have a mean particle size of at most 5 mm, in particular of at most 3 mm, in particular of at most 1.5 mm, in particular of at most 1.0 mm and in particular of at most 0.5 mm. [9] Catalyst material according to any one of the preceding claims, characterized by that the carrier material particles have an outer contour that is essentially spherical or cylindrical. [10] Catalyst material according to any one of the preceding claims, characterized by that the catalytically active material is in the form of nanoparticles, with the mean size of the nanoparticles being at most 5 nm.

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