Classifications

• • 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
  • 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
  • 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
• • 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
  • C01B3/382—Multi-step processes
• • 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
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/06—Combination of fuel cells with means for production of reactants or for treatment of residues
  • H01M8/0606—Combination of fuel cells with means for production of reactants or for treatment of residues with means for production of gaseous reactants
  • H01M8/0612—Combination of fuel cells with means for production of reactants or for treatment of residues with means for production of gaseous reactants from carbon-containing material
• • 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
  • C01B2203/0244—Processes for making hydrogen or synthesis gas containing a reforming step containing a catalytic reforming step the reforming step being an autothermal reforming step, e.g. secondary reforming processes
• • 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
  • C01B2203/0283—Processes for making hydrogen or synthesis gas containing a CO-shift step, i.e. a water gas shift 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
  • C01B2203/08—Methods of heating or cooling
  • C01B2203/0805—Methods of heating the process for making hydrogen or synthesis gas
  • C01B2203/0838—Methods of heating the process for making hydrogen or synthesis gas by heat exchange with exothermic reactions, other than by combustion of fuel
  • C01B2203/0844—Methods of heating the process for making hydrogen or synthesis gas by heat exchange with exothermic reactions, other than by combustion of fuel the non-combustive exothermic reaction being another reforming reaction as defined in groups C01B2203/02 - C01B2203/0294
• • 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
  • C01B2203/1005—Arrangement or shape of catalyst
• • 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
  • C01B2203/1047—Group VIII metal catalysts
  • C01B2203/1064—Platinum group 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
  • C01B2203/14—Details of the flowsheet
  • C01B2203/142—At least two reforming, decomposition or partial oxidation steps in series
• • 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
  • C01B2203/80—Aspect of integrated processes for the production of hydrogen or synthesis gas not covered by groups C01B2203/02 - C01B2203/1695
  • C01B2203/82—Several process steps of C01B2203/02 - C01B2203/08 integrated into a single apparatus
• • 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
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/30—Hydrogen technology
  • Y02E60/50—Fuel cells
• • 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 invention relates to a multilayer catalyst for generating hydrogen by autothermal steam reforming.
• the invention further relates to a method for autothermal steam reforming of hydrocarbons using this catalyst.
• An educt mixture of hydrocarbons, oxygen and water or steam heated to a preheating temperature is passed over a multilayer catalyst which is able to catalyze both the partial oxidation and the steam reforming of hydrocarbons.
• the method is used to generate hydrogen or hydrogen-containing fuel gases in reformer systems, preferably for fuel cells.
• CPO catalytic Partial Oxidation
• ⁇ is defined as the ratio of the number of moles of oxygen used to the number of moles of oxygen required for complete oxidation (see reaction equation (3)):
• the present invention is concerned with a further possibility of hydrogen production, the so-called autothermal steam reforming.
• This process combines steam reforming (equation (1)) with catalytic partial oxidation (equation (2)), the exothermic, partial oxidation providing the necessary heat of reaction for the endothermic steam reforming.
• the starting material mixture can be preheated to a preheating temperature.
• the product mixture is in thermodynamic equilibrium at the temperature prevailing at the reactor outlet.
• Autothermal steam reforming combines the advantages of catalytic partial oxidation (good starting behavior) with those of steam reforming (high hydrogen yields). The process is therefore well suited for the on-board generation of hydrogen for mobile fuel cell systems, but also for use in compact reformers for stationary fuel cell systems.
• US-A-4,415,484 discloses a catalyst for use in an autothermal reforming reactor.
• the catalyst contains 0.01 to 6% rhodium and 10 to 35% calcium oxide on a support made of aluminum oxide, which also contains about 3 to 15% magnesium oxide.
• the catalyst is used in the form of pellets and is particularly characterized by a low tendency to coke at low oxygen / carbon ratios.
• a typical catalyst system for carrying out the autothermal reforming contains approximately One third of its length is an iron oxide catalyst for partial oxidation and two thirds of its length is the rhodium catalyst described. A multilayer catalyst structure is not described.
• WO 98/55227 describes a bifunctional catalyst for the partial oxidation of hydrocarbons, which has both an activity for the dehydrogenation of the hydrocarbons and the ability to selectively oxidize the hydrocarbon chain.
• the dehydrogenation activity is provided by metals of group 8 of the periodic table, while the selective oxidation is carried out by ionized oxygen.
• Oxides that crystallize with a fluorite structure or a perovskite structure, such as zirconium oxide, cerium oxide, bismuth oxide, etc., are sources of ionized oxygen.
• a preferred catalyst is, for example, Pt / CeGdO. It is used in pelletized form with diameters from 1.125 to 1.5 inches (2.8 to 3.8 cm).
• WO 99/48805 describes a process for the catalytic generation of hydrogen by means of a self-sustaining, partial oxidation and steam reforming of hydrocarbons, a mixture of the hydrocarbons and an oxygen-containing gas and optionally steam being reacted over a catalyst which contains rhodium dispersed on a support material , which contains cerium and zirconium as cations.
• the catalyst is used in granular form. A multilayer structure of the catalyst is not described.
• DE 197 27 84t AI describes a method and a device for the autothermal reforming of hydrocarbons, in which the fuel is fed to a two-stage reforming reactor via a feed device.
• the resulting reformate is passed in a heat exchanger in counterflow and in a heat-exchanging manner to starting materials of the reforming which are led from the outside inwards.
• the fuel supplied via the feed device is applied with the starting material directly to the reaction zone having a catalyst, in which the combustion and reforming or catalysis is carried out.
• the reforming reactor contains a honeycomb body coated with catalyst in an upper region and a bed coated with catalyst in a lower region. A honeycomb body can also be used instead of the bed.
• a multi-layer structure of the catalyst is not described here either.
• EP 0 112 613 B1 describes a process for the autothermal reforming of hydrocarbons in which the partial oxidation in zone 1, the steam reforming spatially separated from it, takes place in zone 2.
• Pt and Pd-containing catalysts are used for partial oxidation, and noble metal-containing catalysts for steam reforming.
• a multilayer structure of the catalyst is not disclosed.
• WO 99/33567 describes catalysts for the partial oxidation of hydrocarbons, the monolithic supports of which have a multilayer structure with different porosity.
• the multi-layer structure does not refer to the catalyst itself, but to the carrier substrate.
• the catalyst system contains a first catalytic component based on copper oxide and zinc oxide, which mainly catalyzes steam reforming as the lower layer, as well as a second, upper catalytic layer, which contains a noble metal (platinum or palladium) and a metal oxide, and mainly the partial one Oxidation of methanol activated.
• a noble metal platinum or palladium
• the catalyst system described here cannot be used for the autothermal reforming of hydrocarbons, because the higher temperatures lead to the decomposition or reduction of the base metal oxides (CuO, ZnO) and subsequently to alloying with the noble metal component, so that long-term stability is not ensured ,
• EP 1 157 968 A1 presents a process for the autothermal steam reforming of hydrocarbons which is operated adiabatically and requires a noble metal catalyst on a support body.
• WO 02/18269 A2 describes a catalyst device for hydrogen generation, which has a layered structure.
• This catalyst device consists of a monolith that has a layer that contains a steam reforming catalyst (SR catalyst). This layer is in contact with a layer that contains a catalyst for partial oxidation (CPO catalyst).
• CPO catalyst catalyst for partial oxidation
• the layer with the partial oxidation catalyst (CPO) lies over the layer which contains the steam reforming catalyst.
• the lower catalyst layer contains the steam reforming catalyst, while the upper layer contains the partial oxidation catalyst.
• the invention provides a catalyst and a method for the autothermal, catalytic steam reforming of hydrocarbons using this catalyst.
• the catalyst according to the invention has a multilayer coating on a support body comprising two different catalyst layers, each of which contains at least one platinum group metal on an oxidic carrier material.
• the multilayer coating has a second, upper catalyst layer, which mainly has an activity with regard to steam reforming (according to Eq. (1)) having.
• the layer sequence is exactly the opposite.
• the catalyst mass can have a further catalyst layer, for example for carbon monoxide conversion (“water gas shift reaction”, WGS), which is applied as a third layer in whole or in part on the second coating.
• the catalyst layer for carbon monoxide conversion can be at least one noble metal as catalytically active components contain. More than three-layer structures, for example four-layer arrangements, are also possible.
• an educt mixture of hydrocarbons, oxygen and water or steam heated to a preheating temperature is passed over the catalyst, an adiabatic reaction being carried out.
• the process as a whole is one-stage, that is to say the educt mixture is passed over a single, multilayer catalyst which is capable of providing the energy required for the endothermic steam reforming by the catalytic partial oxidation of the educt mixture.
• the temperature of the educt mixture increases from the preheating temperature to the necessary reaction temperature between 600 and 900 ° C. Partial oxidation and steam reforming smoothly merge into one another on the catalyst.
• the sequence of exothermic catalytic, partial oxidation and endothermic steam reforming as well as subsequent CO conversion result in a uniform temperature profile in the catalytic converter that does not show any major temperature fluctuations and peaks.
• the catalyst according to the invention contains a catalyst mass on a support body, which is applied in the form of a multiple coating on the geometric surfaces of the support body.
• Preferred supporting bodies are monolithic honeycomb bodies made of ceramic or metal, open-cell ceramic or metallic foam bodies, metal sheets or irregularly shaped components.
• the total thickness of the catalytic coating is usually between 20 and 200 ⁇ m.
• the catalyst mass contains, in addition to a first, lower catalyst layer, which preferably catalyzes the partial oxidation, a second, upper catalyst layer which has an activity with regard to steam reforming.
• a schematic representation of a possible structure of the catalyst according to the invention is shown in FIG. 1.
• the catalyst comprises a support body (1) on which a two-layer catalyst mass (2) is applied, which in turn comprises a lower layer (3) and an upper layer (4).
• the lower catalyst layer can catalyze the partial oxidation
• the upper catalyst layer can catalyze the steam reforming.
• the two different catalyst layers each contain at least one platinum group metal on a finely divided, oxidic support material.
• supported catalysts or supported catalysts, in which the Precious metal in high distribution (ie dispersion) is applied to the oxidic support material.
• the term supported catalyst relates only to the catalyst mass and must be distinguished from the catalyst which comprises the support body (1) with the catalyst mass (2) applied to it.
• the lower catalyst layer (3) which catalyzes the partial oxidation, preferably contains 0.1 to 5% by weight of platinum as the noble metal, based on its total weight. Platinum has a high activity for the oxidation of hydrocarbons. To adapt the oxidation activity to the requirements of the process, the catalyst mass can also contain other noble metals, for example palladium or rhodium. A catalyst mass is preferably used which contains platinum on aluminum oxide and rare earth oxides.
• the upper catalyst layer (4) for steam reforming preferably contains 0.1 to 5% by weight of rhodium as the noble metal, based on its total weight. Rhodium has a high activity for steam reforming, while at the same time its oxidation activity is low compared to that of platinum.
• a catalyst mass is preferably used which contains rhodium on an active aluminum oxide. This catalyst layer can additionally contain cerium oxide to reduce soot deposits and to increase sulfur resistance.
• the catalyst mass contains, in addition to the first, lower catalyst layer (which preferably catalyzes the partial oxidation), a middle catalyst layer (which is active with regard to steam reforming), and a third layer which carries out the carbon monoxide (CO) conversion (the So-called water gas shift (“WGS”) reaction).
• the catalyst comprises a support body (1) on which a three-layer catalyst mass (2) is applied, which again comprises a lower layer (3), a middle layer (4) and an upper layer (5.)
• the lower catalyst layer can catalyze the partial oxidation, the middle catalyst layer the steam reforming and the upper layer the carbon monoxide conversion.
• reaction equation (4) is referred to below as carbon monoxide conversion or CO conversion.
• WGS water gas shift reaction
• a shift catalyst containing a noble metal is preferably used for the high-temperature CO conversion with a working temperature between 280 and 550 ° C.
• shift catalysts are known from EP 1 136 441 A2 by the applicant. They contain at least one of the noble metals platinum, palladium, rhodium, ruthenium, iridium, osmium and gold on an oxidic carrier material from the group aluminum oxide, silicon dioxide, titanium oxide, rare earth oxides or mixed oxides thereof or zeolites.
• a CO conversion catalyst based on platinum, palladium and iron is preferably used.
• the reformate gas usually contains 2 to 40% by volume of carbon monoxide and has an inlet temperature of between 300 and 600 ° C resulting from the reforming process.
• Suitable oxidic carrier materials for the platinum group metals are oxides such as aluminum oxide, silicon dioxide, titanium dioxide or mixed oxides thereof and zeolites. Materials with a specific surface area of more than 10 m 2 / g are preferably used in order to enable a highly disperse distribution of the catalytically active components on this large surface area.
• the techniques for producing such a supported catalyst and for coating an inert support body with it are known to the person skilled in the art.
• the catalyst mass can additionally contain at least one oxide selected from boron oxide, bismuth oxide, gallium oxide, oxides of the alkali metals, oxides of the alkaline earth metals, oxides of the subgroup elements and oxides of the rare earth metals, for example in a concentration of up to 70% by weight, based on the Total weight of the catalyst mass included.
• the multilayer catalyst according to the invention has considerable advantages over conventional catalysts.
• the inventors have thus found that, surprisingly, the partial oxidation of the starting material mixture at the inlet of the catalyst is dampened overall by applying the upper catalyst layer (for steam reforming) to the lower, oxidation-active layer. This will make high Avoid temperature peaks that could destroy the catalyst.
• a third catalytically active layer for carbon monoxide conversion (WGS) the yield of hydrogen is also increased and the content of residual hydrocarbons is reduced.
• the method according to the invention can be operated with aliphatic and / or aromatic hydrocarbons (methane, propane, toluene etc.) or hydrocarbon mixtures (e.g. natural gas, gasoline, heating oil or diesel oil).
• hydrocarbon mixtures e.g. natural gas, gasoline, heating oil or diesel oil.
• steam / carbon ratios S / C between 0.7 and 5 can be used.
• the air ratio ⁇ of the educt mixture and its preheating temperature should be chosen so that a temperature between 600 and 900 ° C. is established at the outlet of the catalyst.
• the proposed process is only part of an overall process for the production of hydrogen for mobile and stationary fuel cell units.
• the overall process also comprises further process steps for removing carbon monoxide from the reformate, for example by preferential oxidation of CO (PrOx), methanation or external, low temperature CO conversion.
• PrOx preferential oxidation of CO
• methanation methanation or external, low temperature CO conversion.
• the educt mixture can also be briefly electrically preheated for quick start-up of the reformer system.
• the low thermal mass of the catalyst advantageously leads to full hydrogen production starting after only a few seconds.
• the catalyst mass can be applied to a monolithic support body, which has a length L and is traversed by flow channels from an inlet end surface to an outlet end surface, and a lower catalyst layer lying directly on the support body and an upper catalyst layer lying on the lower catalyst layer contain.
• the lower layer is applied over the entire length L of the support body, and the upper layer is only applied to a certain segment, for example the exit-side part of the support body.
• the exact shape of the layer sequence depends on the construction, the geometry and the mode of operation of the reformer system.
• the following examples and the comparative example are intended to explain the nature of the invention in more detail. However, the invention is not limited to these embodiments.
• Methane is reformed using the process according to the invention, a two-layer catalyst being used.
• the catalyst is a catalytically coated ceramic honeycomb body with a cell density of 62 cells / cm 2 and a volume of 30 ml.
• the lower layer of the two-layer catalyst consists of a platinum / aluminum oxide cerium oxide / zirconium oxide supported catalyst (for CPO).
• the top layer of the catalyst consists of a rhodium / alumina supported catalyst (for SR).
• the total concentration of the catalytic coating is 150 g / 1; the coating concentration of the precious metals is 0.5 g / l platinum and 0.5 g / 1 rhodium.
• the starting materials are heated to 600 ° C. and then passed together over the catalyst.
• the following material flows are used:
• Methane is reformed according to the process of the invention according to Example 1, a two-layer catalyst being used.
• the catalyst is a catalytically coated ceramic honeycomb body with a cell density of 62 cells / cm 2 and a volume of 30 ml.
• the layer sequence from Example 1 is reversed.
• the upper layer of the two-layer catalyst consists of a platinum / aluminum oxide cerium oxide / zirconium oxide supported catalyst (for CPO).
• the lower layer of the catalyst consists of a rhodium / aluminum oxide supported catalyst (for SR).
• the total concentration of the catalytic coating is 150 g / 1; the coating concentration of the precious metals is 0.5 g / l platinum and 0.5 g / 1 rhodium.
• the starting materials are heated to 600 ° C. and then passed together over the catalyst.
• the following material flows are used:
• the input temperature of the mixture of substances is 610 ° C
• the output temperature is 645 ° C.
• the dry reformate of the two-layer catalyst not according to the invention contains 44.5% by volume of hydrogen, compared to 45.9% by volume in the dry reformate of the two-layer catalyst according to the invention from Example 1.
• Table 1 This shows the superiority of the layer sequence according to the invention of the two-layer catalyst system.
• the catalytic coating consists of a rhodium / aluminum oxide supported catalyst and is applied to the honeycomb body in a concentration of 150 g / l.
• the coating concentration of the rhodium is 1 g / 1.
• Methane is reformed according to the procedure described in Example 1.
• the starting materials are again heated to 600 ° C. and then passed together over the catalyst.
• the mass flows of methane, water and air are identical to Example 1.
• the inlet temperature is 605 ° C
• the outlet temperature is 640 ° C.
• the dry reformate of the single-layer catalyst contains 43.4% by volume of hydrogen (compared to 45.9% by volume in the case of the two-layer catalyst according to the invention from Example 1).
• the concentrations of undesired CO (4.8 vol .-%) and residual methane (1.7 vol .-%) are significantly higher.
• the results are also summarized in Table 1. From this one can see the superiority of the multilayer catalyst system according to the invention.
• Methane is reformed by the process according to the invention, a three-layer catalyst being used.
• the catalyst is a catalytically coated ceramic honeycomb body with a cell density of 62 cells / cm 2 and a volume of 30 ml.
• the lower layer consists of a platinum / aluminum oxide / cerium oxide / zirconium oxide supported catalyst (for CPO).
• the middle layer of the catalyst consists of a rhodium alumina supported catalyst (for SR).
• the upper layer consists of a CO conversion catalyst and is attached in the last third of the volume segment (seen in the direction of flow).
• the catalytically active coating of the CO conversion catalyst consists of 1.5% by weight of Pt, 1.0% by weight of Pd and 2.4% by weight of Fe, applied to aluminum oxide / cerium oxide.
• the total concentration of the catalytic coating is 180 g / 1; the coating concentration of the precious metals is 0.8 g / 1 platinum, 0.2 g / 1 palladium and 0.5 g / 1 rhodium.
• the starting materials are heated to 600 ° C. and then passed together over the catalyst.
• the following material flows are used:
• the input temperature of the mixture of substances is 605 ° C, the output temperature is 630 ° C.
• the dry reformate of the three-layer catalyst contains 46.3 vol .-% hydrogen.
• the CO content is only 3.7% by volume.
• Table 1 Results of the multilayer catalysts according to the invention in comparison to a multilayer catalyst with different layer sequence (VB1) and to a conventional single-layer catalyst (VB2) in the autothermal reforming of methane

Landscapes

• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• General Health & Medical Sciences (AREA)
• Health & Medical Sciences (AREA)
• Combustion & Propulsion (AREA)
• Inorganic Chemistry (AREA)
• Manufacturing & Machinery (AREA)
• Sustainable Development (AREA)
• Sustainable Energy (AREA)
• Electrochemistry (AREA)
• General Chemical & Material Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Hydrogen, Water And Hydrids (AREA)
• Catalysts (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

Publications (1)

Family

ID=31197822

Family Applications (1)

Country Status (6)

Cited By (1)

Families Citing this family (32)

Citations (3)

Family Cites Families (12)

• 2002
  • 2002-08-26 EP EP02019014A patent/EP1393804A1/de not_active Withdrawn
• 2003
  • 2003-08-20 US US10/644,377 patent/US7150866B2/en not_active Expired - Fee Related
  • 2003-08-26 WO PCT/EP2003/009449 patent/WO2004024324A1/de not_active Ceased
  • 2003-08-26 EP EP03794941A patent/EP1542800B1/de not_active Expired - Lifetime
  • 2003-08-26 AU AU2003264107A patent/AU2003264107A1/en not_active Abandoned
  • 2003-08-26 JP JP2004535170A patent/JP4950420B2/ja not_active Expired - Fee Related
  • 2003-08-26 CN CNA03823257XA patent/CN1684771A/zh active Pending

Patent Citations (3)

Also Published As

Similar Documents

Legal Events