GB2034194A - Preparing ammonia synthesis catalysts - Google Patents
Preparing ammonia synthesis catalysts Download PDFInfo
- Publication number
- GB2034194A GB2034194A GB7936523A GB7936523A GB2034194A GB 2034194 A GB2034194 A GB 2034194A GB 7936523 A GB7936523 A GB 7936523A GB 7936523 A GB7936523 A GB 7936523A GB 2034194 A GB2034194 A GB 2034194A
- Authority
- GB
- United Kingdom
- Prior art keywords
- catalyst
- range
- surface area
- ammonia
- potassium
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 239000003054 catalyst Substances 0.000 title claims abstract description 38
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 title claims abstract description 30
- 229910021529 ammonia Inorganic materials 0.000 title claims abstract description 15
- 230000015572 biosynthetic process Effects 0.000 title description 5
- 238000003786 synthesis reaction Methods 0.000 title description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 15
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 claims abstract description 15
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims abstract description 12
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 claims abstract description 11
- 229910052700 potassium Inorganic materials 0.000 claims abstract description 11
- 239000011591 potassium Substances 0.000 claims abstract description 11
- 239000007864 aqueous solution Substances 0.000 claims abstract description 10
- 239000000243 solution Substances 0.000 claims abstract description 9
- 229910002804 graphite Inorganic materials 0.000 claims abstract description 8
- 239000010439 graphite Substances 0.000 claims abstract description 8
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 7
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims abstract description 6
- 239000001257 hydrogen Substances 0.000 claims abstract description 6
- 229910052739 hydrogen Inorganic materials 0.000 claims abstract description 6
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 6
- KFIKNZBXPKXFTA-UHFFFAOYSA-N dipotassium;dioxido(dioxo)ruthenium Chemical compound [K+].[K+].[O-][Ru]([O-])(=O)=O KFIKNZBXPKXFTA-UHFFFAOYSA-N 0.000 claims abstract description 4
- 238000000034 method Methods 0.000 claims description 21
- 238000006243 chemical reaction Methods 0.000 claims description 7
- 238000004519 manufacturing process Methods 0.000 claims description 6
- 238000002360 preparation method Methods 0.000 claims description 5
- 229910052751 metal Inorganic materials 0.000 claims description 3
- 239000002184 metal Substances 0.000 claims description 3
- 230000000737 periodic effect Effects 0.000 description 7
- KJTLSVCANCCWHF-UHFFFAOYSA-N Ruthenium Chemical compound [Ru] KJTLSVCANCCWHF-UHFFFAOYSA-N 0.000 description 5
- 229910052783 alkali metal Inorganic materials 0.000 description 5
- 150000001340 alkali metals Chemical class 0.000 description 5
- 229910052707 ruthenium Inorganic materials 0.000 description 5
- 150000001875 compounds Chemical class 0.000 description 4
- 238000005470 impregnation Methods 0.000 description 3
- 229910052723 transition metal Inorganic materials 0.000 description 3
- 150000003624 transition metals Chemical class 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
- -1 compound potassium ruthenate Chemical class 0.000 description 2
- 229910021645 metal ion Inorganic materials 0.000 description 2
- 239000003607 modifier Substances 0.000 description 2
- 150000003623 transition metal compounds Chemical class 0.000 description 2
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- 238000009620 Haber process Methods 0.000 description 1
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 1
- 229910052768 actinide Inorganic materials 0.000 description 1
- 150000001255 actinides Chemical class 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 150000001540 azides Chemical class 0.000 description 1
- 229910002091 carbon monoxide Inorganic materials 0.000 description 1
- 238000006555 catalytic reaction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 150000004820 halides Chemical class 0.000 description 1
- 238000011065 in-situ storage Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N iron oxide Inorganic materials [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 1
- 235000013980 iron oxide Nutrition 0.000 description 1
- VBMVTYDPPZVILR-UHFFFAOYSA-N iron(2+);oxygen(2-) Chemical class [O-2].[Fe+2] VBMVTYDPPZVILR-UHFFFAOYSA-N 0.000 description 1
- 229910052747 lanthanoid Inorganic materials 0.000 description 1
- 150000002602 lanthanoids Chemical class 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- QJGQUHMNIGDVPM-UHFFFAOYSA-N nitrogen group Chemical group [N] QJGQUHMNIGDVPM-UHFFFAOYSA-N 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000002574 poison Substances 0.000 description 1
- 231100000614 poison Toxicity 0.000 description 1
- 239000002243 precursor Substances 0.000 description 1
- 239000000376 reactant Substances 0.000 description 1
- 239000012258 stirred mixture Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
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
- B01J23/54—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
- B01J23/58—Platinum group metals with alkali- or alkaline earth metals
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01C—AMMONIA; CYANOGEN; COMPOUNDS THEREOF
- C01C1/00—Ammonia; Compounds thereof
- C01C1/02—Preparation, purification or separation of ammonia
- C01C1/04—Preparation of ammonia by synthesis in the gas phase
- C01C1/0405—Preparation of ammonia by synthesis in the gas phase from N2 and H2 in presence of a catalyst
- C01C1/0411—Preparation of ammonia by synthesis in the gas phase from N2 and H2 in presence of a catalyst characterised by the catalyst
-
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Analytical Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Catalysts (AREA)
Abstract
A catalyst is prepared by reacting an aqueous solution of potassium perruthenate with sufficient excess potassium hydroxide solution to give a stable aqueous solution of potassium ruthenate. This solution is then used to impregnate a graphite-containing carbon having specified surface area properties. The resulting catalyst is useful for synthesising ammonia from hydrogen and nitrogen.
Description
SPECIFICATION
Catalyst for the production of ammonia
This invention relates to a catalyst for use in a process for the production of ammonia.
With increased pressure on the world's food resources the demand for nitrogen-containing fertilisers based on ammonia has grown rapidly in recent years. Current Haber processes using nitrogen and hydrogen as feedstock generally use a potassium promoted iron catalyst, usually with other promoters such as alumina. These catalysts are reduced in situ from bulk iron oxides before use and operate under severe conditions, e.g., pressures of up to 300 bar and temperatures of 4500--5000C.
The reaction N2 + 3H2 = 2NH3 is highly exothermic and thus the equilibrium is moved to the right at lowertemperatures. However, present day commercial catalysts are not sufficiently active at lower temperatures to enable the reaction to reach equilibrium within the short time the reactants are in contact with the catalyst. Activity increases with temperature and therefore a compromise has to be reached.
Recent work by Aika et al, Journal of Catalysis, 27, 424--431 (1972), on the synthesis of ammonia discloses that synthesis over a ruthenium catalyst is promoted by the addition of an alkali metal, particularly when the ruthenium is supported by active carbon or alumina.
Similarly, British Patent Specification 1367112 to Sagami Chemical Research Centre discloses a complex catalyst for ammonia synthesis which comprises (a) at least one alkali metal belonging to
Group 1 A of the Periodic Table, (b) at least one compound, preferably a halide, oxide or sulphide, of a transition metal selected from the group consisting of Group 4B, Group 5B, Group 6B, Group 7B and
Group 8 of the Periodic Table and graphite. The Periodic Table referred to by Sagami is that given in the "Handbook of Chemistry", edited by Norbert Adolf Lange; McGraw-Hill, 1961; pages 56 to 57.
The complex comprises an alkali metal as the electron donor, graphite as the electron acceptor and a transition metal compound. The alkali metal and the transition metal compound are present as intercalates in the graphite lattice. Aika and Sagami both disclose the use of free alkali metal or precursors thereof, such as azides, as electron donors.
Our copending British Patent Application No. 45711/76 Serial No. 1565074 discloses a catalyst comprising (i) as support a graphite-containing carbon having (a) a basal plane surface area of at least 100 m2/g, (b) a ratio of BET surface area to basal plane surface area of not more than 8:1, preferably not more than 5:1 and (c) a ratio of basal plane surface area to edge surface area of at least 2:1 and preferably at least 5::1 and (ii) as active component (a) 0.1 to 50%, preferably 130%, most preferably 510%, by weight of a transition metal of the 4th, 5th and 6th horizontal Periods of Groups VB, VIB, V11B and VIII of the Periodic Table expressed as % by weight of total catalyst and (b) 0.1 to 4 times by weight of (a) of a modifying metal ion selected from Groups IA or IIA of the Periodic Table or the lanthanides or actinides, the modifying metal ion being actively associated with the transition metal rather than the support.
Unless otherwise indicated the Periodic Table referred to in the present specification is the
Periodic Table published on page B--4 of the Handbook of Chemistry and Physics, 57th Edition, 1976-1977, published by CRC Press, Cleveland, Ohio.
Such a catalyst is suitable for the production of ammonia from hydrogen and nitrogen.
It is distinguished from the prior art in that it is neither an electron donor-acceptor complex nor is it an intercalate compound.
British Patent Application No.45711/76 Serial No. 1565074 further describes the preparation of the catalyst disclosed therein by a two stage impregnation technique. In addition to the second processing step the concentrations of both solutions must be carefully chosen so that the correct molar ratio of active component to modifier is achieved in the final catalyst.
In the case of a potassium/ruthenium catalyst the compound potassium ruthenate, K2RuO4, would provide a catalyst with an acceptable atomic ratio of modifier, i.e., potassium, to active component, i.e., ruthenium, of 2:1 but unfortunately this compound is unstable and is therefore not commercially available.
We have now discovered that this compound can be prepared in solution from potassium perruthenate, KRuO4, and excess potassium hydroxide to give a solution sufficiently stable to impregnate the support in a one stage impregnation technique to give a catalyst with the optimum ratio of potassium to ruthenium.
Thus according to the present invention there is provided a method for the preparation of a catalyst which process comprises reacting an aqueous solution of potassium perruthenate with sufficient excess potassium hydroxide solution to give a stable aqueous solution of potassium ruthenate and impregnating with this solution a graphite-containing carbon having (a) a basal plane surface area of at least 100 m2/g, (b) a ratio of BET surface area to basal plane surface area of not more than 8:1, and (c) a ratio of basal plane surface area to edge surface area of at least 2:1, to give a catalyst with a total metal content of 0.1 to 50% by weight.
The reaction is preferably carried out at elevated temperature, suitably in the range 50 to 1000C.
The concentration of potassium perruthenate in its aqueous solution is suitable in the range 20 to 500 g/l.
The concentration of potassium hydroxide in its aqueous solution is suitably in the range 20 to 500 g/l ratio of basal plane surface area to edge surface area of at least 2:1, to give a catalyst with a total metal content of 0.1 to 50% by weight.
After impregnation, the impregnated support should be dried, e.g., at 1000 to 1 500C for 1-24 hours.
A catalyst according to the present invention is particularly suitable for use in the production of ammonia. It may also be used as a catalyst for the Fischer-Tropsch reaction.
Thus according to another aspect of the present invention, there is provided a process for the production of ammonia which process comprises passing a feedstock containing nitrogen and hydrogen over a catalyst as hereinbefore described under conditions of temperature, pressure and space velocity such that conversion to ammonia is effected.
The catalyst has a high tolerance of poisons which are normally harmful to conventional catalysts, such as water and carbon monoxide.
Synthesis gas is a suitable source of hydrogen and the atmosphere of nitrogen.
Broad and preferred range of process conditions are as follows:- Broad Range Preferred Range
Temperature OC 250--600 300-500 Pressure bars Atmospheric-300 20-200 Space Velocity v/v/hr 1,000-100,000 5,000--30,000 The invention is illustrated with reference to the following Example.
EXAMPLE
0.212 g potassium perruthenate (0.99 m mol) was dissolved in 2 ml water to give a 0.52 M solution.
0.272 g potassium hydroxide (4.12 m mol) dissolved in 4 ml water to give a 1.21 M solution.
The latter was added with stirring to the former and the stirred mixture was heated to and at 800C for 30 minutes to form potassium ruthenate during which time oxygen evolved and ceased to evolve.
1.0 g of a graphite-containing carbon catalyst support'having the properties set out below was added to the solution and the mixture was then evaporated to dryness using a rotary evaporator. The impregnated catalyst was finally dried for 1 6 hours at 1 200C/1 00 m bar.
The resulting catalyst contained 7.3% by wt Ru and 14.6% by wt K, expressed as percentages by weight of the total weight of the catalyst.
Surface Area Properties of Graphite-Containing Carbon Basai Plane Surface Area (bpsa) : 250 m2/g
BET Surface Area (BET sa) : 260 m2/g
Edge Surface Area (esa) : 0.1 m2/g
Ratio of BET sa to bpsa : 1.04:1
Ratio of bpsa to esa : 2,500:1
Claims (11)
1. A method for the preparation of a catalyst which method comprises reacting an aqueous solution of potassium perruthenate with sufficient excess potassium hydroxide solution to give a stable aqueous solution of potassium ruthenate and impregnating with this solution a graphite-containing carbon having (a) a basal plane surface area of at least 100 m2/g, (b) a ratio of BET surface area to basal plane surface area of not more than 8:1, and (c) a ratio of basal plane surface area to edge surface area of at least 2:1, to give a catalyst with a total metal content of 0.1 to 50% by weight.
2. A method according to Claim 1 wherein the reaction is carried out at elevated temperature in the range 500 to 1000C.
3. A method according to either of the preceding claims wherein the concentration of potassium perruthenate in its aqueous solution is in the range 20 to 500 g/l.
4. A method according to any of the preceding claims wherein the concentration of potassium hydroxide in its aqueous solution is in the range 20 to 500 g/l.
5. A process for the production of ammonia which process comprises passing a feedstock containing nitrogen and hydrogen over a catalyst as hereinbefore described under conditions of temperature, pressure and space velocity such that conversion to ammonia is effected.
6. A process according to Claim 5 wherein the feedstock is passed over the catalyst at a temperature in the range 2500 to 6000 C, a pressure in the range atmospheric to 300 bars and a space velocity in the range 1,000 to 100,000 v/v/hr.
7. A process according to Claim 6 wherein the feedstock is passed over the catalyst at a temperature in the range 3000 to 5000C, a pressure in the range 20 to 200 bars (ga) and a space velocity in the range 5,000 to 30,000 v/v/hr.
8. A method for the preparation of a catalyst according to Claim 1 as hereinbefore described with reference to the Example.
9. A process for the preparation of ammonia as hereinbefore described with reference to the
Example.
10. A catalyst whenever prepared by a method according to any of Claims 1 to 4.
11. Ammonia whenever prepared by a process according to Claims 5 to 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB7936523A GB2034194B (en) | 1978-10-24 | 1979-10-22 | Preparing ammonia synthesis catalysts |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB7841709 | 1978-10-24 | ||
| GB7936523A GB2034194B (en) | 1978-10-24 | 1979-10-22 | Preparing ammonia synthesis catalysts |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2034194A true GB2034194A (en) | 1980-06-04 |
| GB2034194B GB2034194B (en) | 1983-01-12 |
Family
ID=26269303
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB7936523A Expired GB2034194B (en) | 1978-10-24 | 1979-10-22 | Preparing ammonia synthesis catalysts |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2034194B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0437608A4 (en) * | 1987-10-30 | 1989-12-14 | Nippon Kokan Kk | METHOD FOR DECOMPOSING AMMONIA. |
| CN117654496A (en) * | 2022-08-25 | 2024-03-08 | 中国科学院理化技术研究所 | Application of a photothermal catalyst in photothermal synergistic catalytic reaction of nitrogen and hydrogen to synthesize ammonia |
-
1979
- 1979-10-22 GB GB7936523A patent/GB2034194B/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0437608A4 (en) * | 1987-10-30 | 1989-12-14 | Nippon Kokan Kk | METHOD FOR DECOMPOSING AMMONIA. |
| CN117654496A (en) * | 2022-08-25 | 2024-03-08 | 中国科学院理化技术研究所 | Application of a photothermal catalyst in photothermal synergistic catalytic reaction of nitrogen and hydrogen to synthesize ammonia |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2034194B (en) | 1983-01-12 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |