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
  • B01J23/74—Iron group metals
  • B01J23/755—Nickel
• • 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
  • B01J23/76—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36

Definitions

• the present invention relates to a catalyst and a process for decomposing an alkanol .
• Methanol can be catalytically decomposed to form carbon monoxide and hydrogen, mixtures of which are known as synthesis gas .
• the catalytic decomposition of methanol can be represented as follows : CH 3 OH - CO + 2H 2
• Methanol has become a widely traded commodity for use primarily in the production of formaldehyde. However it has also found application as a fuel or fuel additive in the transport industry as well as a source of synthesis gas. Synthesis gas derived from methanol has been used in the past as a means of peak shaving in the gas distribution industry. Methanol has also been proposed as a substitute for other fuels used in firing gas turbines . Methanol can be readily manufactured through a series of thermal and catalytic steps from low cost coal, natural gas or biomass. It can also be easily transported and stored.
• methanol has a lower heat of combustion than gasoline or natural gas and therefore a larger volume of methanol is required for equivalent energy production.
• methanol has a lower* heat of combustion than its decomposition products carbon monoxide and hydrogen.
• the catalytic decomposition of methanol to carbon monoxide and hydrogen could provide a more efficient means of using methanol as a fuel especially in motor vehicles.
• Table 1 contains enthalpies of reaction for several methanol decomposition reactions and for the combustion reactions of methanol, synthesis gas, dimethyl ether and methane.
• Table 1 The data contained in Table 1 demonstrate that the energy output of methanol can be improved by catalytically decomposing the methanol into synthesis gas, combusting the synthesis gas, using the energy of combustion to do useful work and recovering waste heat for use in the catalytic decomposition of the methanol.
• the present invention provides a catalyst for decomposing an alkanol which catalyst comprises active metals supported on a suitable carrier wherein the active metals are copper and nickel.
• the present invention provides a process for decomposing an alkanol which process comprises heating an alkanol to an elevated temperature and contacting the heated alkanol with a catalyst comprising active metals supported on a suitable carrier wherein the active metals are copper and nickel.
• the present invention provides a method of improving the energy efficiency of methanol when used as a fuel which method comprises heating methanol to an elevated temperature using waste heat, contacting the heated methanol with a catalyst to form decomposition products, combusting the decomposition products with oxygen in the internal combustion engine to form combustion products, using these combustion products to perform useful work and recovering waste heat for heating the methanol wherein the catalyst comprises active metals supported on a suitable carrier, the active metals being copper and nickel.
• the catalyst of the present invention also improves cold start capability due to its high activity thus reducing the auxiliary energy required to heat the methanol prior to starting.
• the catalyst and process of the present invention are particularly suited to the decomposition of methanol.
• other alcohols such as ethanol and propanol may be decomposed to form a hydrocarbon and hydrogen.
• the copper content of the catalyst may lie in the range from 5 to 95 wt% of the catalyst and the nickel content from 2 to 80 wt%. However preferably the copper content lies in the range from 10 to 80 wt% and the nickel content in the range from 2 to 60 wt%.
• the carrier may comprise silica, magnesia or silica/magnesia.
• the selection of the carrier material has an impact on the activity and selectivity of the catalyst.
• the catalyst is a basic (non-acidic) catalyst.
• the catalyst comprises from 10 to 90 wt% of silica and from 0.1 to 60 wt% of magnesia.
• the preferred catalysts have silica comprising 20 to 80 wt% of the catalyst and magnesia comprising 0.1 to 40% by weight of the catalysts .
• the catalyst of the invention may be prepared by depositing copper and nickel compounds onto the carrier by kneading and/or precipitation and/or impregnating. Precipitation or impregnation may be of organic and/or inorganic compounds from aqueous and/or non-aqueous solutions.
• the carrier material itself may also be prepared by kneading, precipitation and/or impregnation of inorganic and/or organic compounds (for example the silica may be derived from tetramethoxysilane) from aqueous and/or non-aqueous solutions.
• the catalyst may contain a promoter or promoters such as an element or elements from Groups I to VIII of the Periodic Table of Elements. Such a promoter may be added by mixing, precipitation and/or impregnation from an aqueous and/or non-aqueous solution.
• the promoter may comprise from 0.01 to 10 wt% of the catalyst. If alkali metal hydroxide, carbonates or hydrogen carbonates are used during the preparation of the catalyst to precipitate the active metals, the catalyst may contain minor amounts of the alkali metal within the catalyst. These minor amounts may comprise from 0.001 to 10 wt% of the catalyst and may act as a promoter.
• the catalyst may be combined, dispersed or otherwise intimately mixed with an inorganic oxide matrix or matrices in proportions that result in a product containing 10 wt% to 100 wt% of the catalyst.
• Matrices which impart desirable properties to the catalyst such as increased strength, attrition resistance and/or thermal stability are preferred.
• Oxides of aluminium, zirconium, titanium, chromium are examples of such inorganic oxides.
• the decomposition process can be performed in a fixed or fluidised bed of catalyst.
• the process conditions preferred are temperatures up to 1000°C, more preferably 200 to 700°C, a pressure in the range from 0.1 to 50 atmospheres, a methanol mass hourly space velocity (MHSV) in the range from 0.1 to 100 hr "1 , more preferably 0.1 to 50 hr "1 and any other gas or liquid comprising 0 to 95 volume percent of the feed stream.
• MHSV methanol mass hourly space velocity
• Examples 1 to 6 illustrate methods for producing catalysts of the invention and examples 7 to 16 illustrate the preparation of comparative catalysts.
• the precipitate was separated, washed twice with 500 ml of water, was dried overnight at 100°C and was calcined at 550°C. The calcined material was crushed to - 500 ⁇ m and then pelleted.
• Example 2 The preparation of these examples of the catalyst is similar to Example 1 except the amount of copper nitrate was 90g, 67.lg and 29.8g respectively.
• the catalysts according to the invention were used in a number of experiments for the decomposition or dissociation of methanol to hydrogen and carbon monoxide.
• the experiments were carried out in reactors containing a fixed catalyst bed of particles 300-600 micron size.
• the conditions used to carry out these experiments and the results of these experiments are given below in Table 2.
• An aluminium phosphate support was prepared by dissolving 615 g of aluminium nitrate in 4 litres of hot water and adding slowly 190 g of 85% phosphoric acid, followed by 51 g of urea. The solution was heated to 90°C and with vigorous stirring concentrated ammonia solution was added until a pH of 8.3 was obtained. The resultant precipitate was stirred for 3 hours, then collected by filtration, dried at 150°C overnight, calcined at 400°C for 2 hours and ground to ⁇ 1.2 mm.
• silica support Aldrich Silica Gel grade 63, size to -250 +150 ⁇ m and calcined at 500°C for 5 hours
• silica support Aldrich Silica Gel grade 63, size to -250 +150 ⁇ m and calcined at 500°C for 5 hours
• the material was dried at 110°C, calcined at 450°C and then reduced in a 10% H 2 in N 2 stream at 400°C for 2 hours. It was further impregnated with a solution of 24.4 g of Ni(NO 3 ) 2 .6H 2 0 and 6.35 g of Ce(N0 3 ) 3 .6H 2 0 in methanol and then dried and reduced as previously.
• Ludox AS40TM ammonia stablised colloidal silica, DuPont
• 250 g of methanol was mixed with 49.59 g of Ni(N0 3 ) 2 .6H 2 0 dissolved in a minimum amount of methanol.
• the slurry was stirred until a paste then dried at 110°C and calcined overnight at 550°C.
• the catalyst powder was pressed, crushed and sized to -500 ⁇ + 250 ⁇ .
• Example 12 was repeated except the Cu(NO 3 ) 2 .3H 2 0 was replaced with 49.59 g of Ni(N0 3 ) 2 .6H 2 0.
• Example 11 was repeated except the Ni(N0 3 ) 2 .6H 2 0 was replaced with 38.02 g of Cu(N0 3 ) 2 .3H 2 0.
• Example 15 was repeated except the Ni(N0 3 ) 2 .6H 2 0 was replaced with 38.02 g of Cu(N0 3 ) 2 .3H 2 0.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Catalysts (AREA)
• Hydrogen, Water And Hydrids (AREA)

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• 1992
  • 1992-11-13 EP EP92923495A patent/EP0641255A1/de not_active Withdrawn
  • 1992-11-13 JP JP5508827A patent/JPH07504841A/ja active Pending
  • 1992-11-13 WO PCT/AU1992/000613 patent/WO1993009870A1/en not_active Application Discontinuation

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