Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
  • B01D53/34—Chemical or biological purification of waste gases
  • B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
  • B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
  • B01D53/9404—Removing only nitrogen compounds
  • B01D53/9409—Nitrogen oxides
  • B01D53/9413—Processes characterised by a specific catalyst
  • B01D53/9418—Processes characterised by a specific catalyst for removing nitrogen oxides by selective catalytic reduction [SCR] using a reducing agent in a lean exhaust gas
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
  • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
  • B01J23/40—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals of the platinum group metals
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J29/00—Catalysts comprising molecular sieves
  • B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
  • B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
  • B01J29/061—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof containing metallic elements added to the zeolite
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J29/00—Catalysts comprising molecular sieves
  • B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
  • B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
  • B01J29/064—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof containing iron group metals, noble metals or copper
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J35/00—Catalysts, in general, characterised by their form or physical properties
  • B01J35/30—Catalysts, in general, characterised by their form or physical properties characterised by their physical properties
  • B01J35/31—Density
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
  • B01J37/02—Impregnation, coating or precipitation
  • B01J37/0215—Coating
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
  • B01J37/02—Impregnation, coating or precipitation
  • B01J37/024—Multiple impregnation or coating
  • B01J37/0244—Coatings comprising several layers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
  • B01J37/02—Impregnation, coating or precipitation
  • B01J37/024—Multiple impregnation or coating
  • B01J37/0246—Coatings comprising a zeolite
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2255/00—Catalysts
  • B01D2255/20—Metals or compounds thereof
  • B01D2255/207—Transition metals
  • B01D2255/20738—Iron
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2255/00—Catalysts
  • B01D2255/50—Zeolites
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2255/00—Catalysts
  • B01D2255/90—Physical characteristics of catalysts
  • B01D2255/902—Multilayered catalyst
  • B01D2255/9022—Two layers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2255/00—Catalysts
  • B01D2255/90—Physical characteristics of catalysts
  • B01D2255/92—Dimensions
  • B01D2255/9202—Linear dimensions
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2255/00—Catalysts
  • B01D2255/90—Physical characteristics of catalysts
  • B01D2255/92—Dimensions
  • B01D2255/9205—Porosity
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2255/00—Catalysts
  • B01D2255/90—Physical characteristics of catalysts
  • B01D2255/92—Dimensions
  • B01D2255/9207—Specific surface
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2257/00—Components to be removed
  • B01D2257/40—Nitrogen compounds
  • B01D2257/402—Dinitrogen oxide
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J35/00—Catalysts, in general, characterised by their form or physical properties
  • B01J35/30—Catalysts, in general, characterised by their form or physical properties characterised by their physical properties
  • B01J35/396—Distribution of the active metal ingredient
  • B01J35/397—Egg shell like
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J35/00—Catalysts, in general, characterised by their form or physical properties
  • B01J35/60—Catalysts, in general, characterised by their form or physical properties characterised by their surface properties or porosity
  • B01J35/61—Surface area
  • B01J35/613—10-100 m2/g
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J35/00—Catalysts, in general, characterised by their form or physical properties
  • B01J35/60—Catalysts, in general, characterised by their form or physical properties characterised by their surface properties or porosity
  • B01J35/61—Surface area
  • B01J35/615—100-500 m2/g
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J35/00—Catalysts, in general, characterised by their form or physical properties
  • B01J35/60—Catalysts, in general, characterised by their form or physical properties characterised by their surface properties or porosity
  • B01J35/63—Pore volume
  • B01J35/633—Pore volume less than 0.5 ml/g
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02C—CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]
  • Y02C20/00—Capture or disposal of greenhouse gases
  • Y02C20/10—Capture or disposal of greenhouse gases of nitrous oxide (N2O)

Definitions

• the present invention relates to a shaped catalyst body and to the use of the shaped catalyst body, in particular for the reduction of nitrogen oxides and nitrous oxide in stationary installations.
• the residence time variance be as small as possible, as excessively short or long residence of a portion of the mixture may result in undesirable properties of the product or adversely affect the overall catalytic effect.
• extrudates affect the maximum allowable flow velocity, i. also the residence time, which increases with decreasing particle size of the extrudates due to the avoided inertia of the particles.
• omega number ⁇ which contains the sinking rate and material values of the components used and is a function of the Reynolds number.
• the Omega number is also known under the name Ljaschenko number Lj.
• L5 resulting diagram can be assigned a Reynolds number, where for a given particle diameter or a rate of descent, the respective ratio can be calculated and above the valid Reynolds number is determined so that for each catalyst system or
• the Archimedes number is a dimensionless parameter that contains the inertia parameters and characterizes the particle inertia.
• the diameters of a spherical body flow into the Archimedes number, which experiences the same resistance force with the same flow and thus is a parameter for a shaped catalyst body with respect to its effective inflow.
• the density difference between the total density of the total catalyst and the gas density is included in the Archimedes number.
• the object of the present invention was to provide a shaped catalyst body which has the smallest possible extrudate particle size in order to accelerate the transport of the material by enlarging its outer surface, i. a lower residence time, but at the same time has sufficient particle inertia to allow higher flow rates during the catalytic reaction.
• a shaped catalyst body which comprises a core and a first catalytically active layer arranged in regions on the core, wherein the total density of the core is greater than the total density of the catalytically active layer.
• the total density refers to the density of the material taking into account its internal porosity and is defined as the mass (or weight) of the core / shaped body divided by the volume of its outer geometric shape.
• the higher overall density of the core of the shaped catalyst body which is usually significantly higher than the density of the porous bulk extrudates used so far, increases the particle inertia considerably, thus allowing a higher flow velocity during the reaction.
• the ratio of the total density of the core to the total density of the catalytically active layer is in the range from 2: 1 to 10: 1, very particularly preferably in the range from 3: 1 to 5: 1. This also allows a wide variation of the materials of the core, so that a variety of possible carrier materials can be used for the core.
• the thermal conductivity of the core is greater than that of the catalytically active layer.
• the ratio of the thermal conductivity of the core to the thermal conductivity of the catalytically active layer is greater than 10: 1, and more preferably 100: 1.
• the thermal expansion of the shaped catalyst body is approximately equal to that of the reactor housing, whereby the mechanical load on the shaped catalyst body is significantly reduced with temperature fluctuations.
• the core has an increased mechanical strength, so that a longer service life of the shaped catalyst body according to the invention is achieved over a longer period of operation, since the shaped catalyst bodies do not break or splinter as quickly as a result of mechanical stress during delivery or during operation.
• the catalytically active layer may have a higher porosity than the core, since the mechanical strength requirements for the catalytically active layer applied are lower. As a result, an increase in activity can be achieved.
• An increase in the porosity of the catalytically active layer leads to a reduction of the total density or the inertia of the shaped catalyst body and thus also to a reduction of the permissible flow velocity.
• the catalytically active first layer encloses the entire core, so that the catalytically active surface of the shaped body is correspondingly increased in relation to a region-wise arrangement of the catalytically active first layer.
• Prefers the thickness of the catalytically active layer is 5 to 1,000 .mu.m, more preferably 10 to 800 .mu.m.
• Preferred materials for the core include, for example, materials such as ZrO 2 , Al 2 O 3 , SiO 2 , magnesium silicates, ceramics such as mullite, cordierite, carbides, silicates and early transition metal oxides, metals, metal alloys, and glass.
• materials such as ZrO 2 , Al 2 O 3 , SiO 2 , magnesium silicates, ceramics such as mullite, cordierite, carbides, silicates and early transition metal oxides, metals, metal alloys, and glass.
• the material of the core is not zeolite or zeolitic material.
• the core is therefore preferably free of zeolites or zeolitic materials.
• shaped catalyst bodies consist of relatively simple geometries, since hitherto almost only solid extrudates are used.
• Typical shaped bodies are present, for example, in the form of spheres, rings, cylinders, perforated cylinders, trilobes and cones, etc.
• open-cell foam structures and so-called monoliths which have largely mutually parallel channels, which can be interconnected, of a metal, a metal alloy, ceramics such as silicon carbide, Al 2 O 3 , mullite, cordierite or aluminum titanate may also be used as the core become.
• a sheet metal or a sheet metal strip having a thickness of typically less than 1 mm made of any metal or metal alloy, such as films or metal fabrics, which can be made by extrusion, winding, stacking or folding ,
• any metal or metal alloy such as films or metal fabrics, which can be made by extrusion, winding, stacking or folding .
• a core For the purposes of this invention is to be spoken here of a core.
• temperature-resistant alloys of iron, chromium and aluminum are used.
• the first catalytically active layer in further preferred embodiments of the present invention, may consist of a single homogeneous layer or else of several layers. Likewise, this can be applied all at once or in several individual steps. An almost arbitrary sequence of layers is possible, it is only important that a layer contains a catalytically active component.
• the catalytically active second layer contains in preferred embodiments a metal or a metal oxide from the group consisting of rhenium, ruthenium, iron, manganese, osmium, rhodium, iridium, palladium, platinum, copper, silver and gold and mixtures and alloys thereof.
• the catalytically active first layer preferably contains a so-called metal-exchanged zeolite, in which part of the lattice sites in the aluminum silicate of the zeolite are replaced or replaced by metal atoms or metal oxides.
• metals are only active Centers built up from one at several metal atoms inside the pores of the zeolite form.
• Preferred metals for the metal exchange or for the incorporation of such metal species are the elements of the 1st, 3rd, 4th, 5th, and 8th subgroup, preferably Fe, Cu, Co, Ag, Cr, V, W, Ni, most preferably Fe, Cu, Co, Ag or their oxides and mixtures thereof.
• the metal exchange can typically be carried out by methods known per se, such as, for example, aqueous ion exchange impregnating incipient wetness methods or by solid-state exchange.
• aqueous iron salt solutions of chlorides, nitrates or sulphates of iron are used, in the latter case solid iron compounds such as iron sulphate or iron chloride.
• the metal atoms or metal oxides introduced in this way are located either in the zeolitic cavities, which are interconnected, for example, by narrower pores, with the maximum available pore size in each case having a limiting effect on the spatial accumulation of metal atoms.
• the metals may be present both in metallic form and in the form of their oxides or mixed oxides.
• Zeolite is understood here to mean a zeolite within the meaning of the nomenclature of Meyer et al., "Atlas of Zeolite Structure Types", Edition Butterworth-Heinemann, 1996, to which reference is made in its entirety. Likewise, zeolite-like materials are, of course, also usable according to the invention.
• Typical materials are silicates, aluminosilicates, aluminophosphates, metal aluminophosphates, phosphosilicates, titanosilicates or silicoaluminophosphates.
• topological structures of zeolites which can be used according to the invention are AFI, AEL, BEA, CHA, EOU, FAU, FER, KFI, LTL, MAZ, MFI, MOR, REI, OFF, TON.
• the zeolite materials can be present both in their sodium and in their ammonium or H form.
• meso-porous zeolite materials are, for example, the so-called M41S materials which are disclosed in US Pat. No. 5,089,684 and in US Pat. No. 5,102,643 and can likewise be used according to the invention.
• MCM41 and MCM48 Preference is given here, for example, to the topological structures designated MCM41 and MCM48.
• the former is particularly preferred, as it has a hexagonal arrangement of mesopores of uniform size.
• the catalytically active, containing a zeolite first layer has a BET surface area of 10-500 m 2 / g, particularly preferably 20-300 m 2 / g and most preferably from 40 to 150 m 2 / g.
• a good accessibility of the educts of catalysis is possible to the catalytically active centers.
• the BET Surface determined by adsorption of nitrogen according to DIN66132.
• the integral pore volume of the first catalytically active layer can be determined, for example, according to DIN66133 by means of Hg porosimetry and is preferably greater than 100 mm 3 / g, preferably greater than 180 mmVg, more preferably greater than 200 mm 3 / g and very particularly preferably greater than 400 mm 3 / g.
• the first catalytically active layer is applied to the core, which is present for example in the form of a nonwoven, a so-called monolith or a porous foam.
• the catalytically active layer is typically in the form of a so-called washcoat, i. an aqueous suspension, applied, for example by dipping, spraying, etc., wherein the average particle size of the catalytically active component is less than 10 microns, preferably less than 3 microns.
• Dopants for example by means of alkaline earth oxides or early transition metal oxides and rare earth oxides are also possible.
• the fixation of the washcoat suspension on the support by calcination is carried out typically at temperatures of 300-800 0 C.
• the additionally present components in the washcoat can likewise be catalytically active and preferably produce synergistic effects.
• the shaped body according to the invention is used in numerous catalytic reactions which take place in a fixed bed, for example as oxidation catalyst or for the reduction or decomposition of nitrogen oxides and nitrous oxide in stationary installations.
• the measured conversion decreases with increasing particle size while the particle inertia, expressed by the Ar number, and thus the maximum permissible flow velocity increases.
• Fig. 1 also shows the influence of density. By doubling the core density, with the same Ar number, the particle size can be significantly reduced, thereby achieving a significant increase in the conversion.

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• 2007
  • 2007-04-19 DE DE102007018612A patent/DE102007018612A1/de not_active Withdrawn
• 2008
  • 2008-04-21 EP EP08735342A patent/EP2136914A1/de not_active Withdrawn
  • 2008-04-21 CN CN2008800106776A patent/CN101657254B/zh not_active Expired - Fee Related
  • 2008-04-21 US US12/596,278 patent/US20110039689A1/en not_active Abandoned
  • 2008-04-21 WO PCT/EP2008/003194 patent/WO2008128748A1/de not_active Ceased
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