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
  • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
  • B01J23/89—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with noble metals
  • B01J23/8933—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with noble metals also combined with metals, or metal oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
  • B01J23/894—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with noble metals also combined with metals, or metal oxides or hydroxides provided for in groups B01J23/02 - B01J23/36 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
  • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
  • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
  • B01J23/89—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with noble metals
  • B01J23/8906—Iron and noble 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
  • B01J35/00—Catalysts, in general, characterised by their form or physical properties
  • B01J35/40—Catalysts, in general, characterised by their form or physical properties characterised by dimensions, e.g. grain size
• • 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
  • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
  • B01J37/02—Impregnation, coating or precipitation
  • B01J37/0201—Impregnation
• • 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
• • 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
• • 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
  • B01J37/04—Mixing
• • 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
  • B01J37/08—Heat treatment
• • 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
  • B01J37/08—Heat treatment
  • B01J37/082—Decomposition and pyrolysis
  • B01J37/088—Decomposition of a metal salt
• • 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
• • 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
  • C01B3/06—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of inorganic compounds containing electro-positively bound hydrogen, e.g. water, acids, bases, ammonia, with inorganic reducing agents
  • C01B3/12—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of inorganic compounds containing electro-positively bound hydrogen, e.g. water, acids, bases, ammonia, with inorganic reducing agents by reaction of water vapour with carbon monoxide
  • C01B3/16—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of inorganic compounds containing electro-positively bound hydrogen, e.g. water, acids, bases, ammonia, with inorganic reducing agents by reaction of water vapour with carbon monoxide using catalysts
• • 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]
• • 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 belongs to the field of synthesis gas production processes comprising carbon monoxide (CO).
• the invention relates to a process and the associated catalytic reactor for producing a synthesis gas, wherein a gaseous mixture comprising carbon dioxide and hydrogen is contacted with a catalyst to produce carbon monoxide. carbon.
• Carbon dioxide can be converted under appropriate operating conditions into carbon monoxide by the so-called retroconversion reaction, as follows:
• the RWGS reaction is recognized as a very promising way to valorise carbon dioxide and is the subject of many studies.
• the gases it generates, especially carbon monoxide, can synthesize various products, such as for example methanol.
• the RWGS reaction leads to a balance between the different constituents.
• a metal catalyst is generally used to shift this equilibrium to carbon monoxide formation in times consistent with acceptable reactor size.
• US Patent 2003/113244 (reference [3]) therefore proposes to use a catalyst based on zinc oxide and chromium oxide in order to obtain a good reaction rate of the conversion of carbon dioxide to monoxide. of carbon.
• the absence of iron in the catalyst is indicated as essential, this metal element being presented as having the drawback of favoring the side reactions of production of methane and methanol, or even carbon.
• One of the aims of the invention is thus to avoid or mitigate one or more of the disadvantages described above, by proposing a process for producing carbon monoxide using a catalyst which has in particular a deactivation which is low or almost nil. over time, for example after a period of use greater than 100 hours.
• the present invention thus relates to a process for producing a synthesis gas, wherein a gaseous mixture comprising carbon dioxide and hydrogen is contacted with a catalyst to produce carbon monoxide, the process being characterized in that the catalyst comprises iron and silver in a silver mass / iron mass ratio of 0.05 to 0.95.
• the process of the invention is characterized by the use of a catalyst which comprises iron, despite the contrary incitement of the state of the art, as well as silver.
• the catalyst comprises iron and silver in a ratio of silver mass to iron mass (to namely the weight ratio of silver to iron) which is from 0.05 to 0.95, preferably from 0.05 to 0.50 in order to further improve the degree of conversion, more preferably from 0.10 to 0. ,30.
• the optimum proportion of silver tends to increase with the temperature at which the production process of the invention is carried out.
• the silver mass / iron mass ratio may for example be between 0.07 and 0.40, and at 500 ° C. between 0.1 and 0.5.
• the catalyst also comprises cerium in a ratio of cerium mass / iron mass (ie the weight ratio of cerium to iron) which is 0.1 to 1, preferably 0.2 to 0.6.
• the weight ratio of silver to iron remains in the ranges indicated above.
• cerium further enhances the properties of the catalyst comprising iron and silver, such as the reaction rate of the conversion of carbon dioxide to carbon monoxide, possibly decreasing the catalyst activation time, while avoiding the spurious reactions of methane formation or carbon deposition.
• the invention also relates to a catalytic reactor that can be used in the production process as defined in the present description, in particular in one or more of the variants described for this process and for the catalyst that it implements, the reactor containing a reaction chamber in which is disposed a catalyst comprising iron and silver in a ratio mass of silver / mass of iron which is 0.05 to 0.95.
• a verb such as “to understand”, “to include”, “to incorporate”, “to include” and its conjugate forms are open terms and thus do not exclude the presence of element (s) and / or additional step (s) adding to the element (s) and / or initial step (s) set forth after these terms.
• these open terms also include a particular embodiment in which only the element (s) and / or initial stage (s), to the exclusion of all others, are targeted; in which case the term “open” also refers to the closed term “consisting of", “constituting” and its associated forms.
• the catalyst used in the production process of the invention is such that iron, silver and, if appropriate, cerium are present independently of one another in native form and / or in oxide form. .
• the iron oxidizes because of the catalyst preparation process or the presence of water. It forms, for example, an oxide such as magnetite (Fe 3 O 4 ).
• Cerium is generally in the form of an oxide, for example in the form of cerium dioxide (CeO 2 ).
• the money is in native form.
• weight ratios of silver to iron or cerium to iron indicated above are the ratios between the masses of iron, silver or cerium as metallic elements contained in the catalyst, without considering in the calculation of the weight ratio the fact that they are optionally in the form of a compound such as an oxide.
• the catalyst may contain other chemical species, constituting, for example, inevitable impurities of manufacture, as long as these species do not significantly affect the catalytic properties. Impurities are for example present in the catalyst at a concentration of less than 1%, or even 0.5%. When the impurity is copper, the concentration may be less than 5%.
• the catalyst can be made by any method known to those skilled in the art.
• the catalyst is preferably obtained in the usual manner by subjecting a solution comprising an iron nitrate, a silver nitrate and optionally a cerium nitrate, to a precipitation step such as, for example, coprecipitation or oxidation. simultaneous precipitation (known under the term "oxyprecipitation”), followed by a calcination step.
• a precipitation step such as, for example, coprecipitation or oxidation.
• a precipitation step is for example carried out at
• the calcination step may be carried out at a temperature of between 350 ° C. and 450 ° C. for 12 hours and / or in the presence of oxygen, for example in air, a metal oxide may then be formed.
• the catalyst is generally in the form of a powder more or less agglomerated.
• the average size of the constitutive grains of the powder is generally between 20 ⁇ m and 500 ⁇ m, or even between 20 ⁇ m and 100 ⁇ m, after optional sieving, in which case the grains of the powder have, for example, a BET specific surface area of 50 m 2 / g at 200 m 2 / g.
• the catalyst can be used as such in the production process of the invention, or impregnated on a carrier or mixed with a carrier.
• a support usually used in the field of catalysis is suitable for such an embodiment.
• Such a carrier is generally inert with respect to physicochemical conditions, reagents and products of the RWGS reaction. It is for example made of alumina, zeolite or silica. It can be shaped, for example as granules or beads.
• the catalyst may constitute a catalytic bed arranged for example in a fixed-bed or fluidized-bed catalytic reactor, a catalytic bed through which the gaseous mixture passes.
• the catalyst is, for example, in the form of catalytic particles with a BET surface area of at least 50 m 2 / g, for example from 50 m 2 / g to 200 m 2 / g. It can also be mixed with or impregnated onto particles of the inert carrier described above.
• the catalyst In the fixed bed reactor, the catalyst is disposed in a generally vertical cylindrical vessel.
• the bed thus formed is traversed by the flow of the gaseous mixture and the synthesis gas obtained, in order to keep the particles in suspension.
• the catalyst is generally in the form of a powder, kept in suspension by the upward passage of the gaseous mixture.
• the catalyst may be pretreated by subjecting it to hydrogen mixed with helium, water vapor, carbon monoxide, or mixtures thereof. This pretreatment activates at best the catalytic phases of iron. It is carried out for example for a period of 1 hour to 5 hours at a temperature between 200 ° C and 350 ° C.
• the amount of catalyst or the duration of its implementation can vary according to large proportions which may for example depend on the temperature, the reaction volume, the use or not of a continuous regime, the flow rate of the gas mixture, the specific surface of the catalyst. Those skilled in the art can easily adapt the amount or duration of implementation of the catalyst according to the conditions it meets to obtain the catalytic activity or the desired conversion rate.
• the hourly volumetric velocity of the gaseous mixture entering the catalytic bed is between 10,000 Nm 3 / hour and 30,000 Nm 3 / hour per m 3 of catalyst.
• 1 Nm 3 represents the volume of one cubic meter under normal conditions of temperature and pressure, namely 25 ° C and 1 bar.
• the hourly volumetric velocity generally increases with the amount of catalyst.
• the catalyst can be used continuously or discontinuously, for a duration for example greater than 100 hours, or even 200 hours, for example between 100 hours and 3000 hours, all by preserving a stable or relatively stable rate of carbon dioxide conversion.
• the production process of the invention is generally carried out under a pressure of 1 bar at 50 bar, and / or all or part of this process at a temperature between 400 ° C and 550 ° C, preferably between 420 ° C and 520 ° C, knowing that the conversion rate generally increases with temperature.
• the gaseous mixture treated according to the production method of the invention comprises carbon dioxide and hydrogen, generally representing at least 50% by volume of the gaseous mixture, particularly at least 70%, even more particularly at least 90%.
• the molar ratio in the gaseous mixture of hydrogen and carbon dioxide can vary widely between 0.1 and 100. It is for example between 0.8 and 10, and more particularly between 2 and 4.
• the initial gas mixture may further comprise at least one chemical species such as water vapor, methane, carbon monoxide or a chemically inert gas (such as for example argon or 1 helium).
• at least one chemical species such as water vapor, methane, carbon monoxide or a chemically inert gas (such as for example argon or 1 helium).
• the gaseous mixture can come from reforming hydrocarbons with steam or oxygen. It then contains mainly carbon monoxide, carbon dioxide and hydrogen.
• Carbon dioxide can also be the tail gas of an ammonia production unit.
• the synthesis gas obtained at the end of the production process of the invention contains carbon monoxide and water generally in the form of steam, as well as carbon dioxide and unreacted hydrogen, see possibly a small amount of carbon products from parasitic reactions. These carbon products are by methane, the concentration of which is generally less than 1%, more particularly 0.5%, more particularly 0.1%.
• the production method of the invention comprises a supplementary step during which at least one cycle consisting of i) extracting all or part of the water contained in the synthesis gas and then ii ) repeat the production process. By displacement of the reaction equilibrium, this extraction favors the RWGS reaction and thus the enrichment of the synthesis gas with carbon monoxide by conversion of an additional fraction of carbon dioxide.
• Extraction of all or part of the water can be carried out by conventional means such as desiccation or preferably condensation.
• the condensation is for example carried out by bringing the synthesis gas to a temperature between 0 ° C and 70 ° C, preferably between 35 ° C and 55 ° C.
• the condensation temperature may however vary depending on the pressure of the synthesis gas.
• the synthesis gas can be used to synthesize a hydrocarbon which is for example methanol, dimethyl ether or paraffin.
• composition of the synthesis gas obtained is measured by gas chromatography at the outlet of the catalytic bed. This measurement makes it possible to calculate the converted carbon dioxide level: it corresponds to the molar fraction of carbon dioxide converted into carbon monoxide.
• An aqueous solution comprising an iron (Fe (03) 3) and silver (AgNO 3) metal nitrate and optionally a cerium nitrate (Ce (O 3) 3) is produced.
• the nitrates present in the solution are coprecipitated at 70 ° C. after addition of sodium hydroxide in order to reach a pH of 10.
• each metallic element Fe, Ag and Ce is then present at the concentration in which it occurs. will find in the catalyst.
• the precipitates obtained are washed, filtered, dried at 70 ° C. for 24 hours, and calcined under air at 350 ° C. for 4 hours and then at 450 ° C. for 8 hours.
• a powder whose average grain size is between 20 ⁇ m and 500 ⁇ m is obtained, and which constitutes the catalyst that can be used in the process of production of the invention. After sieving, only grains with an average size of less than 100 ⁇ m are preserved, such a particle size generally making it possible to obtain a better efficiency of the catalyst.
• a glass tube is then filled with a variable amount of the catalyst to obtain a fixed bed catalytic reactor which is placed vertically in a temperature controlled oven.
• the catalyst Before carrying out the conversion of the gaseous mixture, the catalyst is conditioned by sweeping it for 2 hours with a stream of hydrogen mixed with helium.
• catalysts based on iron and chromium and possibly copper, or iron and cerium are manufactured by coprecipitation of the corresponding nitrates (or chloride in the case of chromium), integrated in the form of a catalytic bed and conditioned by hydrogen sweeping.
• the composition of the catalysts obtained is expressed as a percentage by weight. Their specific surface is similar. 2. Catalytic conversion of a gaseous mixture at a temperature of 450 ° C.
• Each catalyst is separately implemented in the form of a fixed catalytic bed in order to carry out catalytic conversions of the gaseous mixture at a temperature of 450 ° C. (+/- 2 ° C.).
• Catalytic conversion according to the invention. Catalysts comprising iron, silver and, where appropriate, cerium, make it possible to obtain the following conversion kinetics:
• Each catalyst is separately implemented as a fixed catalyst bed in order to catalytically convert the gaseous mixture to a temperature of 500 ° C (+/- 2 ° C).
• Catalysts comprising iron, silver and, where appropriate, cerium, make it possible to obtain the following conversion kinetics:

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• 2012
  • 2012-07-04 FR FR1256434A patent/FR2992954B1/fr not_active Expired - Fee Related
• 2013
  • 2013-07-04 WO PCT/FR2013/051586 patent/WO2014006335A1/fr active Application Filing
  • 2013-07-04 EP EP13747435.9A patent/EP2870105A1/de not_active Withdrawn
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