Classifications

• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B3/00—Hydrogen; Gaseous mixtures containing hydrogen; Separation of hydrogen from mixtures containing it; Purification of hydrogen
  • C01B3/02—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen
  • C01B3/32—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of gaseous or liquid organic compounds with gasifying agents, e.g. water, carbon dioxide, air
  • C01B3/34—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of gaseous or liquid organic compounds with gasifying agents, e.g. water, carbon dioxide, air by reaction of hydrocarbons with gasifying agents
  • C01B3/38—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of gaseous or liquid organic compounds with gasifying agents, e.g. water, carbon dioxide, air by reaction of hydrocarbons with gasifying agents using catalysts
  • C01B3/40—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of gaseous or liquid organic compounds with gasifying agents, e.g. water, carbon dioxide, air by reaction of hydrocarbons with gasifying agents using catalysts characterised by the catalyst
• • 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
  • B01J23/54—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
  • B01J23/56—Platinum group metals
  • B01J23/63—Platinum group metals with rare earths or actinides
• • 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
  • B01J37/009—Preparation by separation, e.g. by filtration, decantation, screening
• • 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
  • B01J37/03—Precipitation; Co-precipitation
  • B01J37/031—Precipitation
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10K—PURIFYING OR MODIFYING THE CHEMICAL COMPOSITION OF COMBUSTIBLE GASES CONTAINING CARBON MONOXIDE
  • C10K3/00—Modifying the chemical composition of combustible gases containing carbon monoxide to produce an improved fuel, e.g. one of different calorific value, which may be free from carbon monoxide
  • C10K3/02—Modifying the chemical composition of combustible gases containing carbon monoxide to produce an improved fuel, e.g. one of different calorific value, which may be free from carbon monoxide by catalytic treatment
  • C10K3/026—Increasing the carbon monoxide content, e.g. reverse water-gas shift [RWGS]
• • 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
  • B01J23/42—Platinum
• • 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
  • B01J23/46—Ruthenium, rhodium, osmium or iridium
  • B01J23/462—Ruthenium
• • 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
  • B01J23/46—Ruthenium, rhodium, osmium or iridium
  • B01J23/464—Rhodium
• • 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
  • B01J35/50—Catalysts, in general, characterised by their form or physical properties characterised by their shape or configuration
  • B01J35/56—Foraminous structures having flow-through passages or channels, e.g. grids or three-dimensional monoliths
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
  • C01B2203/02—Processes for making hydrogen or synthesis gas
  • C01B2203/0205—Processes for making hydrogen or synthesis gas containing a reforming step
  • C01B2203/0227—Processes for making hydrogen or synthesis gas containing a reforming step containing a catalytic reforming step
  • C01B2203/0238—Processes for making hydrogen or synthesis gas containing a reforming step containing a catalytic reforming step the reforming step being a carbon dioxide reforming step
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
  • C01B2203/10—Catalysts for performing the hydrogen forming reactions
  • C01B2203/1041—Composition of the catalyst
  • C01B2203/1047—Group VIII metal catalysts
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
  • C01B2203/10—Catalysts for performing the hydrogen forming reactions
  • C01B2203/1041—Composition of the catalyst
  • C01B2203/1082—Composition of support materials
• • 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
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P20/00—Technologies relating to chemical industry
  • Y02P20/141—Feedstock
• • 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
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P20/00—Technologies relating to chemical industry
  • Y02P20/50—Improvements relating to the production of bulk chemicals
  • Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts

Definitions

• the present invention relates to a process for reducing carbon dioxide comprising the step of reacting carbon dioxide and hydrogen in the presence of a catalyst to form carbon monoxide and water.
• the invention further relates to the use of such a catalyst in the reduction of carbon dioxide.
• WGS water gas shift reaction
• WO 03/082741 A1 discloses a homogeneous ceria-based mixed metal oxide, usable as a catalyst support, a cocatalyst and / or apparatus having a relatively large surface area per unit weight, typically above 150 m 2 / g, of a structure of nanocrystals Diameters less than 4 nm and including pores larger than the nanocrystals with diameters in the range of 4 to 9 nm.
• the ratio to pore volume, Vp, to framework volume or volume of the skeletal structure, Vs is typically less than 2.5, and the surface area per volume of oxide material is greater than 320 m 2 / cm 3 for low internal resistance to mass transfer and large effective surface area for reaction activity.
• the mixed metal oxide is ceria-based, comprises Zr and / or I I and is prepared by a co-precipitation process.
• a fumed catalyst metal typically a noble metal, e.g. 6. Pt, may be loaded onto the mixed metal oxide support from a solution containing catalyst metal following a selected acid surface treatment of the oxide support. Appropriately selecting a ratio of Ce and other metal constituents of the oxide support material contribute. to maintain a cubic phase to increase the catalytic performance.
• Rhenium is preferably further charged onto the mixed metal oxide support and passivated to increase the activity of the catalyst.
• the metal-loaded mixed metal oxide catalyst is particularly useful in water-gas shift reactions, in conjunction with fuel treatment systems, e.g. 6. in fuel cells.
• US 2004/175327 A1 describes a process, catalysts and a fuel processing apparatus for producing a hydrogen-rich gas such as hydrogen-rich synthesis gas.
• a CO-containing gas contacts a WGS catalyst in the presence of water, preferably at a temperature of less than about 450 ° C, to form a hydrogen-rich gas such as hydrogen-rich synthesis gas.
• a WGS catalyst which is formulated from the following components: a) at least one member of the group consisting of Rh, Ni, Pt, their oxides and mixtures; b) at least one member of the group Cu, Ag, Au, their oxides and mixtures; and c) at least one of K, Cs, Sc, Y, Ti, Zr, V, Mo, Re, Fe, Ru, Co, Ir, Pd, Cd, In, Ge, Sn, Pb, Sb, Te , La, Ce, Pr, nd. Sm, Eu, their oxides and mixtures.
• Another disclosed catalyst formulation comprises Rh, its oxides or mixtures, Pt, its oxides and mixtures and Ag, its oxides and mixtures.
• the WGS catalyst may be supported on, for example, one or more of alumina, zirconia, titania, ceria, magnesia, lanthana, niobia, zeolite, perovskite, silicate-alumina, yttria, and iron oxide, fuel comprising such WGS catalysts Processing devices are also disclosed.
• WO 2011/056715 A I relates to a catalyst support for use with various catalysts in hydrogenation reactions of carbon dioxide, comprising a catalyst support material and an active material capable of catalyzing the RWGS reaction.
• a catalyst for hydrogenating carbon dioxide may be disposed on the catalyst carrier.
• a method of making such a hydrogenation catalyst comprises applying a material capable of catalysing the RWGS reaction to a catalyst support material with optional calcination, and applying a catalyst for the hydrogenation of carbon dioxide to the coated catalyst support material.
• a process for the hydrogenation of carbon dioxide and for the production of synthesis gas comprises a reforming step of hydrocarbons, in particular methane, and an RWGS step using the described catalyst composition and its products.
• WO 2008/055776 A1 discloses a process for preparing a catalytic composition comprising a catalytically active metal and a solid support, wherein a portion of the catalytically active metal is distributed on the outer surface of the support and another part in the core structure of the solid support and wherein the solid support is a refractory oxide and ion-conducting oxide.
• the present invention therefore has the object to provide a method for carrying out the RWGS reaction, which with a cost-effective catalyst with high
• Activity and selectivity and long-term stability at high temperatures can be operated.
• This object is achieved by a method for the reduction of carbon dioxide, comprising the step of the reaction of carbon dioxide and hydrogen in the presence of a catalyst to form carbon monoxide and water, wherein the reaction is carried out at a temperature of> 700 ° C and the catalyst Comprising metal oxide, wherein the mixed metal oxide (I) is a mixture of at least two different metals Ml and M2 on a support comprising an oxide of Al, Ce and / or Zr doped with a metal M3; and or
• (II) a reaction product of (I) in the presence of carbon dioxide, hydrogen, carbon monoxide and / or water at a temperature of> 700 ° C;
• Ml and M2 are independently selected from the group: Re, Ru, Rh, Ir, Os, Pd and / or Pt;
• M3 is selected from the group: Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd. Tb. Oy. Ho, he. Tm, Yb and / or Lu. It has surprisingly been found that the catalysts used according to the invention or their conversion products under the prevailing reaction conditions are stable catalysts which are comparable with industrial benchmark systems in at least one respect.
• the RWGS Reakt ion can be selectively operated at the elevated temperatures according to the invention. It should be noted at this point that the present invention relates to the recovery of CO and III by RWGS reaction. This is in contrast to the WGS reaction, where the reverse reaction may also be to CO and! I) leads.
• the process according to the invention is preferably carried out such that the conversion of CO 2 after completion of the reaction (in particular after leaving a reactor such as, for example, an axial flow reactor) is more than 35 mol%, preferably more than 40 mol%, more preferably more than 45 mol% and most preferably above 50 mole%.
• Preferred mixed metal oxides are, for example, those in which the metals M 1 and M 2 are different and M 3 is Ce. Included in the invention is the case that the oxide of Al, Ce and / or Zr doped with a metal M3 is a Ce-Zr-Al oxide (then M3 would be Ce).
• mixed metal catalysts are supported on high-temperature stable, preferably oxide-conducting, mixed metal oxides (for example cerium-doped zirconium dioxide / aluminum oxide combination) are suitable. In this case, a synergistic effect is achieved in the catalyst by the two-component metal combinations.
• Mixed metal oxides of the abovementioned type (I) can be prepared, inter alia, by physical (such as PVD) and chemical methods, the latter predominantly in the solid phase or liquid phase. Examples include precipitation, co-precipitation, sol-gel process, impregnation, ignition / combustion methods and further gas phase methods such as CVD.
• the invention is the one that eliminates the problem
• reaction products includes the catalyst phases present under reaction conditions.
• the gas mixture to which the catalyst is exposed during the reaction comprising carbon dioxide, hydrogen, carbon monoxide and water may contain these four components, for example, in a content of> 80% by weight, preferably> 90% by weight and more preferably> 95% by weight ,
• a reaction temperature of> 700 ° C is provided.
• the reaction temperature is> 850 ° C, and more preferably> 900 ° C.
• a hydrocarbon having 1 to 4 C atoms is added during the reaction.
• Suitable hydrocarbons are, in particular, alkanes having 1 to 4 C atoms, methane being particularly suitable.
• the addition of the hydrocarbon takes place at arbitrary positions along the longitudinal axis of the reactor.
• a hydrocarbon addition at the reactor inlet, at the reactor outlet and / or at a position between inlet s and outlet take place.
• the hydrocarbon may, for example, in a proportion of> 0.01% by volume to ⁇ 20% by volume, preferably> 0.1% by volume to ⁇ 10% by volume and more preferably> 1% by volume to ⁇ 10% by volume , based on the total volume of the reaction gases, are added. Regardless, it is preferred that the concentration of the hydrocarbon after the reaction, especially at the outlet of a reactor in which the reaction is carried out, is ⁇ 20% by volume and preferably ⁇ 10% by volume.
• the mixed metal oxide comprises Pt-Rh on Ce-Zr-Al oxide, Pi-Ru and / or Rh-Ru on Ce-Zr-Al oxide. It is further preferred that the weight proportion of Pt, Rh and Ru is in each case> 0.01% by weight to ⁇ 10% by weight, based on the total weight of the mixed metal oxide. Preference is given to proportions of> 0.1% by weight to ⁇ 5% by weight.
• the reaction is carried out at a temperature of> 700 ° C to ⁇ 1300 ° C. More preferred ranges are> 800 ° C to
• the reaction is carried out at a pressure of> 1 bar to ⁇ 200 bar.
• the pressure is> 2 bar to ⁇ 50 bar, more preferably> 10 bar to ⁇ 30 bar.
• the catalyst is applied to a support and the support is selected from the group comprising oxides, carbides, nitrides, phosphides and / or borides of aluminum, silicon and / or zirconium.
• the support is selected from the group comprising oxides, carbides, nitrides, phosphides and / or borides of aluminum, silicon and / or zirconium.
• An example of this is SiC. Further preferred is cordierite.
• the reaction is operated in auto thermal mode. This can be achieved, for example, both by the addition of oxygen in the educt gas, as well as that hydrogen-rich residual gases such as anode residual gas, PSA residual gas, natural gas (preferably methane) and / or additional hydrogen in the presence of CO2 fuel gas sources.
• hydrogen-rich residual gases such as anode residual gas, PSA residual gas, natural gas (preferably methane) and / or additional hydrogen in the presence of CO2 fuel gas sources.
• Another object of the present invention is the use of a catalyst comprising a mixed metal oxide in the reaction of carbon dioxide and hydrogen to form carbon monoxide and water, the catalyst comprising a mixed metal oxide comprising (I) a mixture of at least two different metals Ml and M2 is on a support comprising an oxide of Al, Ce and / or Zr doped with a metal M3; and or
• reaction products of (I) in the presence of carbon dioxide, hydrogen, carbon monoxide and / or water at a temperature of> 700 ° C comprises;
• M 1 and M2 are independently selected from the group: Re, Ru. Rh. Ir. Os, Pd and / or Pt; and
• reaction products includes the catalyst phases present under reaction conditions.
• the mixed metal oxide (I) comprises Pt-Rh on Ce-Zr-Al oxide, Pt-Ru and or Rh-Ru on Ce-Zr-Al oxide. It is further preferred that the weight proportion of Pt, Rh and Ru is>
• the catalyst is applied to a support and the support is selected from the group comprising oxides, carbides, nitrides, phosphides and / or borides of aluminum, silicon and / or zirconium.
• the support is selected from the group comprising oxides, carbides, nitrides, phosphides and / or borides of aluminum, silicon and / or zirconium.
• An example of this is SiC.
• Further preferred is cordierite.
• FIG. 1 shows schematically an expanded view of a reactor for carrying out the process according to the invention.
• FIG. 2-4 show turnover curves for CO2 in various RWGS experiments
• the reaction can be carried out in a flow reactor which, viewed in the flow direction of the reaction gases, comprises a plurality of heating levels 100, 101, 102, 103, which are electrically heated by means of heating elements 110, 11, 12, 13. wherein the heating levels 100, 101, 102, 100 are flowed through by the reaction gases, wherein at least one heating element 1 10, 1 1 1, 1 12, 1 13, the catalyst is arranged and can be heated there and at least once an intermediate level 200, 201, 202 between two heating levels 100, 101, 102, 103 is arranged, wherein the intermediate level 200, 201, 202 is also permeable by the reaction gases.
• the reactor has a plurality of (in the present case four) heating levels 1 00, 1 01, 1 02, 103, which are electrically heated by means of respective heating elements 1 10, 1 1 1, 1 12, 1 13 ,
• the Hei / levels 100, 101, 102, 103 are flowed through during operation of the reactor from the reaction gases and the heating elements 1 10, 1 1 1, 1 12, 1 13 are contacted by the reaction gases.
• At least one heating element 1 10, III. 1 12, 1 13, the catalyst is arranged and is heated there.
• the catalyst can directly or indirectly with the heating elements 1 10, 1 1 1, 1 12, I 1 be connected, so that these heating elements represent the catalyst support or a support for the catalyst support.
• the heat supply of the reaction takes place electrically and is not introduced from the outside by means of radiation through the walls of the reactor, but directly into the interior of the reaction space. It is realized a direct electrical heating of the catalyst.
• heating conductor alloys such as FeCrAl alloys are preferably used.
• metallic materials it is also possible to use electrically conductive Si-based materials, particularly preferably SiC, and / or carbon-based materials.
• an intermediate ceramic level 200, 201, 202 (which is preferably supported by a ceramic or metal support framework / plane) is arranged at least once between two heating levels 100, 101, 102, 103, the intermediate level (FIG. n) 200, 201, 202 or the contents 210, 21 1, 212 of an intermediate level 200, 201, 202 are also flowed through in the operation of the reactor from the reaction gases. This has the effect of homogenizing the fluid flow. It is also possible that additional catalyst is present in one or more intermediate levels 200, 201, 202 or other isolation elements in the reactor. Then an adiabatic reaction can take place.
• the pressure in the reactor can take place via a pressure-resistant steel jacket.
• suitable ceramic insulation materials it can be achieved that the pressure-bearing steel is exposed to temperatures of less than 200 ° C and, if necessary, less than 60 ° C.
• the electrical connections are shown in FIG. 1 only shown very schematically. They can be performed in the cold area of the reactor within an insulation to the ends of the reactor or laterally from the heating elements 110, III. 1 12, 1 13 are performed, so the actual electrical connections can be provided in the cold region of the reactor.
• the electrical heating is done with direct current or alternating current.
• the use of the electrically heated elements in the inlet region of the reactor also has a positive effect with regard to the cold start and starting behavior, in particular with regard to rapid heating to the reaction temperature and better controllability.
• the catalyst can in principle be present as a loose bed, as a washcoat or else as a monolithic shaped body on the heating elements 110, 111, 112, 113. However, it is preferred that the catalyst is directly or indirectly connected to the heating elements 110, 111, 112, 113, so that these heating elements represent the catalyst carrier or a carrier for the catalyst support. It is also possible that additional catalyst is present in one or more intermediate levels 200, 201, 202 or other isolation elements in the reactor.
• heating levels 100, 101, 102, 103 heating elements 1 10, 1 1 1, 1 12, 1 13 are arranged, which are spirally, meandering, gitt erförmig and / or net-shaped.
• the 212 comprise a material resistant to the reaction conditions, for example a ceramic foam. They serve for the mechanical support of the heating levels 100, 101, 102, 103 as well as for the mixing and distribution of the gas flow. At the same time an electrical insulation between two heating levels is possible. It is preferred that the material of the content 210, 211, 212 of an intermediate level 200, 201, 202 comprises oxides, carbides, nitrides, phosphides and / or bicycles of aluminum, silicon and / or zirconium. An example of this is SiC. Further preferred is cordierite.
• the intermediate level 200, 201, 202 may include, for example, a loose bed of solids. These solids themselves may be porous or solid, so that the fluid flows through gaps between the solids. It is preferred that the material of the solid bodies comprises oxides, carbides, nitrides, phosphides and / or borides of aluminum, silicon and / or zirconium. An example of this is SiC. Further preferred is cordierite.
• the intermediate level 200, 201, 202 comprises a one-piece porous solid.
• the fluid flows through the intermediate plane via the pores of the solid.
• honeycomb monoliths as used for example in the exhaust gas purification of internal combustion engines.
• the average length of a heating plane 100, 101, 102, 103 in the direction of flow of the fluid and the average length of an intermediate level 200, 201, 202 in the flow direction of the fluid are in a ratio of> 0.01 : 1 to ⁇ 100: 1 to each other. Even more advantageous are ratios of> 0.1: 1 to ⁇ 10: 1 or 0.5: 1 to ⁇ 5: 1.
• At least one heating element 110, III.112, 113 can have a different amount and / or type of catalyst from the other heating elements 110, III.112, 113.
• the heating elements 110, 111, 112, 113 are arranged so that they can each be electrically heated independently of each other. Accordingly, in the method according to the invention, the individual heating elements 110, 111, 112, 113 can be operated with a different heating power.
• the individual heating levels can be individually controlled and regulated.
• In the reactor inlet area can be dispensed with a catalyst in the heating levels as needed, so that only the heating and no reaction takes place in the inlet area. This is particularly advantageous in terms of starting the reactor.
• a temperature profile adapted for the respective reaction can be achieved. With regard to the application for endothermic equilibrium reactions, this is, for example, a temperature profile which achieves the highest temperatures and thus the highest conversion at the reactor outlet.
• the reactor can be modular.
• a module may include, for example, a heating level, an intermediate level, the electrical contact and the corresponding further insulation materials and thermal insulation materials.
• the pH of the suspension was adjusted to 6.5 with sodium carbonate solution (concentration see table).
• the noble metal salt solution was added dropwise at a constant pH of 6.5 (maintained by adding the Na 2 C03 solution) to the carrier suspension.
• the mixture was then stirred for a further 30 minutes and then cooled to room temperature. Thereafter, the suspension was filtered off and then washed 5-10 times with 200 ml of water (60 ° C) chloride-free (after silver nitrate test).
• the moist solid was dried at room temperature in a vacuum oven overnight.
• Ru-Pt 4 0.08 RuCl 3 about 40 0.05
• Example 2 Empty Measurements The following table summarizes the results of the catalyst comparison in the RWGS reaction.
• the indication "X7.5h (CC> 2) [%]” means the conversion of CO2, here after 7.5 hours, expressed in mole percent.
• the term “r eff (C0 2 )” indicates the average reaction rate of CO2 and "X7.5h (C 02) / X 3h (C O 2)” is the quotient of the CC conversion after 7.5 hours and after 3 hours ,
• FIG. 2 illustrate the CO2 conversion curves over the duration of the reaction.
• the thermodynamic limitation at about 60% conversion is indicated by "TD".
• the curves are shown in FIG. 2 indistinguishable, so that was omitted on a curve inscription. There are no or very little activities.
• Example 3 Comparison between Rh / Pt mixtures and Rh or Pt
• the following table summarizes the results of the catalyst comparison in the RWGS reaction for the rhodium- and / or platinum-containing catalysts from Example 1 together.
• the term “7.5h (C02) [%]” means the conversion of CO2, here after 7.5 hours, expressed in mole percent.
• the term “r e ff; 7,5h (C02)” indicates the corresponding average reaction rate of CO2 and "7,5h (C02) / 3h (C02)” is the quotient of the CC conversion after 7.5 hours and After 3 hours.
• FIG. 3 shows the CC> 2 conversion curves over the reaction time for the Rh catalyst (curve “Rh / Ce-Zr-A10 x "), the Pt catalyst (curve “Pt / Ce-Zr-A10 x ”) and for the mixed catalyst (curve” Rh-Pt / Ce-Zr-A10 x ").
• the thermodynamic limitation at about 60% conversion is indicated by "TD”. The highest activity and stability are observed for the deposited Rh-Pt system.
• Example 4 Comparison between Ru / Pt mixtures and Ru or Pt
• the following table summarizes the results of the catalyst comparison in the RWGS reaction for the ruthenium- and / or platinum-containing catalysts from Example 1.
• X7.5h (C02) [%] means the conversion of CO2, here after 7.5 hours, expressed in mole percent.
• the term "r e ff; 7.5h (CC>2)” indicates the corresponding average reaction rate of CO2 and "X7.5h (CO 2) / X 3h (CO 2)" is the quotient from the CC conversion to 7.5 Hours and after 3 hours.
• FIG. 4 shows the CO2 conversion curves over the reaction time for the Ru catalyst (curve “Ru / Ce-Zr-A10 x "), the Pt catalyst (curve “Pt / Ce-Zr-A10 x ”) and for the mixed catalyst (curve “Ru-Pt. Ce-Zr-AlO x ").
• the thermodynamic limitation at about 60% conversion is indicated by "TD”. The highest activity and stability are observed for the supported Ru-Pt system.

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• 2013
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