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
  • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
  • B01J37/08—Heat treatment
  • B01J37/082—Decomposition and pyrolysis
  • B01J37/086—Decomposition of an organometallic compound, a metal complex or a metal salt of a carboxylic acid
• • 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
  • B01J27/00—Catalysts comprising the elements or compounds of halogens, sulfur, selenium, tellurium, phosphorus or nitrogen; Catalysts comprising carbon compounds
  • B01J27/24—Nitrogen compounds
  • B01J27/25—Nitrates
• • 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
  • B01J37/16—Reducing
  • B01J37/18—Reducing with gases containing free hydrogen
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B32/00—Carbon; Compounds thereof
  • C01B32/50—Carbon dioxide
• • 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
  • B01J37/06—Washing
• • 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
  • B01J37/12—Oxidising
  • B01J37/14—Oxidising with gases containing free oxygen

Definitions

• the invention relates to the catalytic oxidation of carbon monoxide.
• the invention relates to the selective oxidation of carbon monoxide in the presence of hydrogen.
• the invention relates to catalyst compositions effective in the oxidation of carbon monoxide.
• the invention relates to removing as much carbon monoxide as possible, preferably all carbon monoxide, from a stream containing carbon monoxide and hydrogen, particularly, to provide hydrogen feedstock for fuel cells.
• a fuel cell is an electrochemical device that enables converting the chemical energy of fuels directly to electricity.
• a hydrogen-air polymer electrolyte membrane (PEM) fuel cell stack is currently considered the best means for adapting this technology to most uses.
• the PEM fuel cell is most efficient using gaseous hydrogen for fuel.
• a fuel processor can convert fuels such as alcohol, gasoline, liquid petroleum gas, or natural gas to a hydrogen-rich stream.
• a fuel processor can convert fuels such as alcohol, gasoline, liquid petroleum gas, or natural gas to a hydrogen-rich stream.
• By a process of steam reforming a stream consisting primarily of hydrogen, carbon dioxide and carbon monoxide can be produced, but the product is generally saturated with water. Processing this stream in a shift reactor reduces the carbon monoxide content to provide relatively more hydrogen by means of the well known water-gas-shift reaction.
• This reaction provides a product that contains from 0.2 to 2 percent carbon monoxide by volume which is sufficient to poison the platinum-based catalyst at the PEM anode. It has now been found that, among other possibilities for removing carbon monoxide to the level necessary to prevent poisoning of the PEM catalyst, the same catalyst that is used to recombine carbon monoxide and oxygen in carbon dioxide lasers can be used to provide hydrogen feedstock for fuel cells on a level of carbon monoxide removal that is commercially viable. The operating conditions for the processes are essentially different.
• the removal of carbon monoxide by selective oxidation of a stream containing both carbon monoxide and hydrogen can be accomplished using the same catalyst as used in carbon dioxide lasers by controlling an increased oxygen flow to the oxidation process, raising the operating temperature of the oxidation process and avoiding reaction between oxygen and hydrogen as compared to the conditions used to recombine carbon monoxide and oxygen in carbon dioxide lasers.
• a process for the selective oxidation of carbon monoxide to carbon dioxide in a gaseous mixture comprising hydrogen and carbon monoxide.
• an amount of free oxygen is mixed with the gaseous mixture comprising hydrogen and carbon monoxide to provide a second gaseous mixture having an enhanced oxygen to carbon monoxide mol ratio.
• the second gaseous mixture is contacted with a catalyst comprising platinum and iron impregnated on a support material.
• the carbon monoxide in the second gaseous mixture is thereby substantially completely converted to carbon dioxide.
• the process for oxidizing carbon monoxide in a feed stream that also contains hydrogen can be carried out so that the CO is selectively oxidized in preference to the oxidation of the hydrogen thereby providing a means to deliver a highly pure hydrogen stream for fuel cell operation in which the oxidation of carbon monoxide in a hydrogen fuel can be integrated into a total package for generating a hydrogen-rich feedstock at the point of use.
• the feed gas to the oxidation process can be formed in any suitable manner, such as by mixing the hydrogen that contains carbon monoxide contaminant with the O 2 containing air at any point before contact with the catalyst.
• the process for oxidizing a feed containing carbon monoxide and hydrogen gas can be carried out at any pressure conditions, for any length of time, any gas hourly space velocity and any volume ratio of O 2 to CO that is suitable for selective oxidation of CO in the presence of hydrogen specified in a temperature range of about 0°C to about 300°C, preferably in a range of about 25°C to about 250°C, and most preferably in a range of about 50°C to about 200°C.
• the pressure during the oxidation process generally is in the range of about 68.9 kPa to about 6890 kPa (about 10 psia to about 1000 psia), preferably about 96.4 kPa to about 1378 kPa (about 14 psia to about 200 psia).
• the ratio of mols of O 2 in the feed gas to the mols of CO in the feed gas will generally be in the range of about 0.5 to 8.0 mol O 2 /mol CO, preferably 0.5 to 4.0 mol O 2 /mol CO, most preferably 0.5 to 1.5 mol O 2 /mol CO.
• the gas hourly space velocity (cc feed gas per cc catalyst per hour) can be in the range of about 100 to about 200,000, preferably from about 5,000 to about 50,000.
• the hydrogen will generally be in the range of about 50-90 volume percent and the inlet CO will generally be in the range of about 0.1 to about 5 volume percent.
• the preparation of the catalyst useful in this invention can be carried out by the process disclosec in USPN 5,017,357 and USPN 4,943,550, which disclose processes using the catalyst for the recombination of carbon monoxide and oxygen for carbon dioxide lasers.
• any of the well known support materials containing metal oxide can be used as support material for the composition of matter used as catalyst in the process of this invention.
• alumina aluminum oxide
• titania titania
• magnesium aluminate spinel More preferably, the support material can contain at least 95 weight percent Al 2 O 3 or magnesium aluminate. These materials are readily available commercially.
• the surface area of the support material which can be determined by the BET/N, method (ASTM D3037), is in the range of about 10 m 2 /g to about 350 m 2 /g.
• the support can be spherical, cylindrical, trilobal, quadrilobal, ringlike or irregular in shape.
• Spherical support material generally has a diameter in the range of from about 0.2 mm to about 20 mm, preferably from about 1 mm to about 5 mm.
• the support can also be an inert porous, ceramic material in any of the shapes cited above and coated with aluminum oxide and/or magnesium aluminate spinel.
• the impregnation of the support material with platinum and iron can be carried out in any suitable manner.
• compounds of platinum and compounds of iron are dissolved in a suitable solvent, preferably water, to prepare a solution of suitable concentration, generally containing from about 0.005 g to about 5.0 g platinum per cc of solution and about 0.005 g to about 5.0 g iron per cc of solution.
• suitable compounds of both platinum and iron are nitrates, carboxylates and acetylacetonates, among others, with acetylacetonates currently preferred.
• Organic solvents, such as methanol, ethanol, acetone, ethyl acetate, toluene and the like can be used as solvents for platinum or iron according to this invention. Currently, acetone is preferred.
• the support material can be soaked in a solution containing platinum compounds and/or iron compounds or can be sprayed with such a solution to impregnate the support.
• the ratio of impregnating solution to support material is generally such that the final composition of the catalyst contains 0.05 to about 10 weight percent platinum, preferably about 0.1 to about 5 weight percent platinum and about 0.05 to about 20 weight percent iron, preferably from about 0.1 to about 4 weight percent iron. It is in the scope of this invention to use any weight percentage of platinum and iron at which they act as copromoters of the oxidation of CO with O 2 . It is presently preferred to spray a solution containing compounds of both metals onto the support, but the metal compounds can also be added separately in any order.
• the impregnated support material is heated to a temperature sufficient to drive off the solvent used in the impregnation.
• a flow of inert gas across the support material can be used.
• a temperature in the range of up to about 250°C applied for about an hour is usually sufficient for the purpose.
• the dried catalyst is heat treated in an oxidizing atmosphere, preferably in an atmosphere containing free oxygen (such as air) generally at a temperature ranging from about 80°C to about 700°C for a time ranging from about 0.5 hr to about 10 hours.
• the heat treatment is preferably done in incremental substeps. Currently, the heat treatment is carried out at 150°C for 1 hour, 200°C for 2 hours and 400°C for 3 hours. Any combination of heating at a temperature for a time sufficient to calcine the impregnated support material to obtain at least one platinum oxide, optionally mixed with metallic platinum, and at least one iron oxide satisfies the requirements of this invention.
• platinum/iron impregnated support is subjected to a reduction reaction which can be carried out in any suitable manner, preferably at a temperature in the range of about 20°C to about 650°C, more preferably from about 200°C to about 500°C.
• Any reducing gas can be used, such as a gas containing hydrogen, CO, gaseous hydrocarbons such as methane, mixtures of the above and the like.
• a free hydrogen containing gas is employed.
• the reducing step can be carried out for any suitable period of time from about 1 minute to about 20 hours, preferably from about 1 hour to about 5 hours.
• the reduced, platinum/iron impregnated support can be further treated by contact with any suitable organic or inorganic acid having a pH of less than about 7.
• any suitable organic or inorganic acid having a pH of less than about 7.
• an aqueous solution of nitric acid or of a carboxylic acid (preferably acetic acid) is used.
• the previously reduced platinum/iron impregnated support is preferably soaked in about 0.01-16 mole/L of HNO 3 generally at a temperature of about 10°C to about 80 °C for a period of about 0.01 to about 1 hour, but sufficiently to obtain incipient wetness.
• the impregnated support material is heated to a temperature sufficient to drive off the solvent used in the acid treatment. A flow of inert gas across the support material can be used.
• a temperature in the range of up to about 250°C applied for about an hour is usually sufficient for the purpose.
• the dried, acid treated catalyst is heat treated in an oxidizing atmosphere, preferably in an atmosphere containing free oxygen (such as air) generally at a temperature ranging from about 80°C to about 700°C for a time ranging from about 0.5 hr to about 10 hours.
• the heat treatment is preferably done in incremental substeps. Currently, the heat treatment is carried out at 150°C for 1 hour, 200°C for 2 hours and 400 °C for 3 hours. Any combination of heating at a temperature for a time sufficient to calcine the impregnated support material to obtain at least one platinum oxide, optionally mixed with metallic platinum, and at least one iron oxide satisfies the requirements of this invention.
• the oxidized, acid-treated, supported platinum/iron catalyst can be activated by a reduction step that can be carried out in any suitable manner, preferably at a temperature of about 20 °C to about 650°C, more preferably about 200°C to about 500°C for about 0.5 hour to about 20 hours, preferably about 1 hour to about 5 hours to enhance the activity of the catalyst composition for catalyzing a low temperature oxidation of CO with O 2 in the presence of hydrogen.
• Any reducing gas can be used: hydrogen, CO, paraffins and the like and mixtures thereof.
• a catalyst precursor was prepared by weighing about 500 grams of 1/8 inch alumina spheres (Alcoa S-100 activated alumina) into two medium porcelain bowls and calcined at 800 °C for 16 hours in a an air-purged muffle furnace. 400 grams of the dry, calcined alumina was placed in a large porcelain bowl and- using a conventional, plastic, hand spray bottle- was sprayed with an impregnating solution prepared by dissolving 8.07 grams of platinum (II) acetylacetonate (platinum (II) 2,4 pentanedionate) and 10.13 grams of iron (III) acetylacetonate in about 650 cc of acetone.
• the support was stirred frequently to assure an even distribution of the solution.
• the catalyst was placed in a draft oven and heated at 175 °C for 45 minutes to an hour thereby driving off the acetone and partially decomposing the metal acetylacetonates.
• the processes of spraying, stirring and heating were repeated three more times.
• the catalyst was divided equally into portions of about 202 grams each and placed in an air-purged muffle furnace heated at 150°C for 1 hour, 200°C for 2 hours and 400°C for 3 hours. This heat treatment provided two 202 gram portions of oxidized 1.0 weight percent platinum/ 0.4 weight percent iron on alumina as catalyst precursor.
• Catalyst A A 202 gram portion of catalyst precursor was transferred to a 2 inch diameter quartz reactor which was then mounted in a vertical tube furnace.
• the catalyst was activated by reducing at 300°C with about 200 cc/min hydrogen gas downflow at atmospheric pressure for three hours.
• the catalyst and reactor were cooled under hydrogen flow followed by nitrogen purge thereby providing an activated catalyst. This is Catalyst A.
• EXAMPLE III Another 202 gram portion of the catalyst precursor was transferred to a 2 inch diameter quartz reactor and mounted in a vertical tube furnace.
• the catalyst was reduced at 300° C with about 200 cc/min hydrogen gas downflow at atmospheric pressure for three hours.
• the catalyst and reactor were cooled under hydrogen flow followed by nitrogen purge.
• the freshly reduced catalyst was poured into a large bowl and impregnated in a ventilated hood with about 60 cc of concentrated nitric acid.
• the acid impregnation was done dropwise with stirring. The impregnation was done as quickly as possible to minimize oxidation by exposure to atmospheric oxygen.
• the acid treated catalyst was dried and calcined in an air-purged muffle furnace heated at 150°C for 1 hour, 200°C fo.
• catalyst B 2 hours and 400°C for 3 hours.
• the catalyst was transferred to a 2 inch diameter quartz reactor which was then mounted in a vertical tube furnace.
• the catalyst was activated by reducing at 300°C with about 200 cc/min hydrogen gas downflow at atmospheric pressure for three hours.
• the catalyst and reactor were cooled under hydrogen flow followed by nitrogen purge thereby providing an activated, acid-treated catalyst. This is catalyst B.
• EXAMPLE IV For these conversion runs the following equipment was used. There were two separate Brooks 5850E mass flow controllers- one for the CO feed blend and one for airflow. The CO blend was held in a 30-liter, aluminum, high-pressure cylinder. The CO blend normally was 1.0 percent CO with the balance being hydrogen. The air was supplied by an in house system. The CO blend and air-streams were joined at the inlet to a jacketed glass tube with an outer jacket for circulating coolant. The glass tube was cooled by a temperature controlled circulating bath which could control the temperature to a specific temperature chosen from within a range of 5°C to about 100°C. The catalyst was loaded inside the glass tube.
• the catalyst was prepared as set out in Examples I-III. A quantity of 2.0 grams of the treated catalyst was loaded into the glass tube with mesh quartz chips packed into the void space. Each catalyst was pretreated by heating to 97 °C for one hour with 100 cc/min of hydrogen flow through the catalyst bed. The tests were run with conditions as shown in the table below. All runs were carried out at ambient pressure, at 10,000 cc feed gas per cc catalyst per hour, GFTSV (gas hourly space velocity) using a feed of 1 percent CO in hydrogen. Data were taken every 15 minutes with the 30 minute results recorded as the result of the test run.
• cat is catalyst
• react temp is reaction temperature
• conv is conversion
• select is selectivity

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• Chemical & Material Sciences (AREA)
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• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Inorganic Chemistry (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Catalysts (AREA)
• Hydrogen, Water And Hydrids (AREA)
• Carbon And Carbon Compounds (AREA)

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• 2000
  • 2000-11-10 KR KR1020027008283A patent/KR20020074465A/ko active IP Right Grant
  • 2000-11-10 JP JP2001549290A patent/JP2003519067A/ja active Pending
  • 2000-11-10 WO PCT/US2000/042050 patent/WO2001047806A1/en not_active Application Discontinuation
  • 2000-11-10 EP EP00993603A patent/EP1257502A4/en not_active Withdrawn
  • 2000-11-10 BR BR0016815-7A patent/BR0016815A/pt not_active Application Discontinuation
  • 2000-11-10 CA CA002395761A patent/CA2395761A1/en not_active Abandoned
  • 2000-11-10 AU AU29239/01A patent/AU774521B2/en not_active Ceased
  • 2000-11-10 RU RU2002120497/15A patent/RU2248323C2/ru not_active IP Right Cessation
  • 2000-11-10 MX MXPA02006437A patent/MXPA02006437A/es not_active Application Discontinuation
  • 2000-11-10 CN CN00817964A patent/CN1414923A/zh active Pending
• 2002
  • 2002-06-28 NO NO20023180A patent/NO20023180L/no not_active Application Discontinuation

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