GB2288341A - Catalysts for the shift reaction - Google Patents
Catalysts for the shift reaction Download PDFInfo
- Publication number
- GB2288341A GB2288341A GB9506693A GB9506693A GB2288341A GB 2288341 A GB2288341 A GB 2288341A GB 9506693 A GB9506693 A GB 9506693A GB 9506693 A GB9506693 A GB 9506693A GB 2288341 A GB2288341 A GB 2288341A
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- United Kingdom
- Prior art keywords
- particles
- iron
- catalyst precursor
- chromium
- catalyst
- Prior art date
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- Granted
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- 239000003054 catalyst Substances 0.000 title claims abstract description 29
- 238000006243 chemical reaction Methods 0.000 title description 7
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 61
- 239000002245 particle Substances 0.000 claims abstract description 43
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 claims abstract description 32
- 229910052742 iron Inorganic materials 0.000 claims abstract description 30
- 239000008188 pellet Substances 0.000 claims abstract description 29
- 239000012018 catalyst precursor Substances 0.000 claims abstract description 20
- 239000011651 chromium Substances 0.000 claims abstract description 13
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims abstract description 12
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 12
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 claims abstract description 8
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims abstract description 7
- 239000011787 zinc oxide Substances 0.000 claims abstract description 4
- 150000001845 chromium compounds Chemical class 0.000 claims description 13
- 239000000203 mixture Substances 0.000 claims description 10
- 238000000034 method Methods 0.000 claims description 8
- 239000002244 precipitate Substances 0.000 claims description 8
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims description 5
- 229910002091 carbon monoxide Inorganic materials 0.000 claims description 5
- 239000010949 copper Substances 0.000 claims description 5
- 229910052751 metal Inorganic materials 0.000 claims description 5
- 239000002184 metal Substances 0.000 claims description 5
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 4
- 238000001354 calcination Methods 0.000 claims description 4
- 229910052802 copper Inorganic materials 0.000 claims description 4
- 150000002739 metals Chemical class 0.000 claims description 4
- 238000004519 manufacturing process Methods 0.000 claims description 3
- QPLDLSVMHZLSFG-UHFFFAOYSA-N Copper oxide Chemical compound [Cu]=O QPLDLSVMHZLSFG-UHFFFAOYSA-N 0.000 claims description 2
- 239000005751 Copper oxide Substances 0.000 claims description 2
- 239000004411 aluminium Substances 0.000 claims description 2
- 229910052782 aluminium Inorganic materials 0.000 claims description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 2
- 229910000431 copper oxide Inorganic materials 0.000 claims description 2
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 claims 1
- 229910052748 manganese Inorganic materials 0.000 claims 1
- 239000011572 manganese Substances 0.000 claims 1
- 150000004682 monohydrates Chemical class 0.000 claims 1
- 230000001376 precipitating effect Effects 0.000 claims 1
- 239000002243 precursor Substances 0.000 description 17
- 239000000243 solution Substances 0.000 description 17
- 230000000694 effects Effects 0.000 description 15
- 238000001556 precipitation Methods 0.000 description 12
- 239000007789 gas Substances 0.000 description 8
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 6
- QDOXWKRWXJOMAK-UHFFFAOYSA-N dichromium trioxide Chemical compound O=[Cr]O[Cr]=O QDOXWKRWXJOMAK-UHFFFAOYSA-N 0.000 description 5
- 238000010438 heat treatment Methods 0.000 description 5
- CDBYLPFSWZWCQE-UHFFFAOYSA-L sodium carbonate Substances [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 5
- 150000003467 sulfuric acid derivatives Chemical class 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- 239000013078 crystal Substances 0.000 description 4
- 229910052598 goethite Inorganic materials 0.000 description 4
- AEIXRCIKZIZYPM-UHFFFAOYSA-M hydroxy(oxo)iron Chemical compound [O][Fe]O AEIXRCIKZIZYPM-UHFFFAOYSA-M 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- 239000005749 Copper compound Substances 0.000 description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 239000001569 carbon dioxide Substances 0.000 description 3
- 229910002092 carbon dioxide Inorganic materials 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 3
- 150000001880 copper compounds Chemical class 0.000 description 3
- 229910052595 hematite Inorganic materials 0.000 description 3
- 239000001257 hydrogen Substances 0.000 description 3
- 229910052739 hydrogen Inorganic materials 0.000 description 3
- LIKBJVNGSGBSGK-UHFFFAOYSA-N iron(3+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[Fe+3].[Fe+3] LIKBJVNGSGBSGK-UHFFFAOYSA-N 0.000 description 3
- SZVJSHCCFOBDDC-UHFFFAOYSA-N iron(II,III) oxide Inorganic materials O=[Fe]O[Fe]O[Fe]=O SZVJSHCCFOBDDC-UHFFFAOYSA-N 0.000 description 3
- 239000002002 slurry Substances 0.000 description 3
- 229910000029 sodium carbonate Inorganic materials 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 2
- 229910001593 boehmite Inorganic materials 0.000 description 2
- 230000003197 catalytic effect Effects 0.000 description 2
- 150000001844 chromium Chemical class 0.000 description 2
- JOPOVCBBYLSVDA-UHFFFAOYSA-N chromium(6+) Chemical class [Cr+6] JOPOVCBBYLSVDA-UHFFFAOYSA-N 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- FAHBNUUHRFUEAI-UHFFFAOYSA-M hydroxidooxidoaluminium Chemical compound O[Al]=O FAHBNUUHRFUEAI-UHFFFAOYSA-M 0.000 description 2
- 150000002823 nitrates Chemical class 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 239000000376 reactant Substances 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- KKCBUQHMOMHUOY-UHFFFAOYSA-N Na2O Inorganic materials [O-2].[Na+].[Na+] KKCBUQHMOMHUOY-UHFFFAOYSA-N 0.000 description 1
- 239000005864 Sulphur Substances 0.000 description 1
- XFBXDGLHUSUNMG-UHFFFAOYSA-N alumane;hydrate Chemical compound O.[AlH3] XFBXDGLHUSUNMG-UHFFFAOYSA-N 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- PHFQLYPOURZARY-UHFFFAOYSA-N chromium trinitrate Chemical class [Cr+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O PHFQLYPOURZARY-UHFFFAOYSA-N 0.000 description 1
- GRWVQDDAKZFPFI-UHFFFAOYSA-H chromium(III) sulfate Chemical class [Cr+3].[Cr+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O GRWVQDDAKZFPFI-UHFFFAOYSA-H 0.000 description 1
- 238000000975 co-precipitation Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- XTVVROIMIGLXTD-UHFFFAOYSA-N copper(II) nitrate Chemical class [Cu+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O XTVVROIMIGLXTD-UHFFFAOYSA-N 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 239000003085 diluting agent Substances 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 238000010348 incorporation Methods 0.000 description 1
- 229910021506 iron(II) hydroxide Inorganic materials 0.000 description 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
- 229910021519 iron(III) oxide-hydroxide Inorganic materials 0.000 description 1
- NCNCGGDMXMBVIA-UHFFFAOYSA-L iron(ii) hydroxide Chemical compound [OH-].[OH-].[Fe+2] NCNCGGDMXMBVIA-UHFFFAOYSA-L 0.000 description 1
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 description 1
- 150000002736 metal compounds Chemical class 0.000 description 1
- -1 metals nitrates Chemical class 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 239000012047 saturated solution Substances 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 231100000331 toxic Toxicity 0.000 description 1
- 230000002588 toxic effect Effects 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
Classifications
-
- 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
-
- 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
- B01J23/84—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 with arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
- B01J23/85—Chromium, molybdenum or tungsten
- B01J23/86—Chromium
- B01J23/862—Iron and chromium
-
- 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
Abstract
Catalyst precursor pellets, suitable for use, after reduction, as high temperature shift catalysts, comprising oxides of iron and chromium and including particles having an aspect ratio of at least 2 and an average (by weight) maximum dimension of at least 500 nm. The particles are preferably acicular and particularly are acicular iron oxide, alumina, or zinc oxide particles.
Description
Catalvsts
This invention relates to catalysts and in particular to iron oxide/chromia catalysts. and precursors thereof, for use for the shift reaction. i.e. the reaction of carbon monoxide and steam to produce carbon dioxide and hydrogen.
Iron oxide/chromia shift catalysts are conventionally made by precipitation of iron and chromium compounds (that decompose to the oxides upon heating) from a solution of iron and chromium salts by the addition of a suitable alkaline reactant. e.g. sodium hydroxide or carbonate. The resulting precipitate is then washed, dried, and caicined and tableted to form catalyst precursor pellets. Prior to use for the shift reaction, the pellets are subjected to reduction conditions wherein the iron oxide is reduced to magnetite (Fe3O4) and any chromlurn trioxide present reduced to the sesquioxide. chromia (Cr2O). This reduction is often carried out in the reactor wherein the shift reaction is to be effected.
We have found that the activity of the catalyst may be significantly increased by incorporating into the catalyst precursor particles of aspect ratio of at least 2 and a maximum dimension of at least 5000 A (500 nm), and preferably less than 15000 A (1500 nm).
Accordingly the present invention provides catalyst precursor pellets comprising oxides of iron and chromium and including particles having an aspect ratio of at least 2 and an average (by weight) maximum dimension of at least 500 nm.
The particles preferably have an average length in the range 600 to 1500 nm: the activity advantage given by the invention decreases if longer particles are employed.
By the term aspect ratio we mean that the ratio between the maximum dimension and the minimum dimension of the particles. The particles may thus be plate-like where the length and breadth are at least twice the thickness. Alternatively. and preferably, the particles are acicular. wherein the average length is at least twice. preferably at least 2.5 times. the breadth, e.g having a "rod" configuration wherein the cross sectional dimensions, i.e. breadth and thickness are approximately equal. or a "lath" configuration. wherein the thickness is significantly less than the breadth.
In the conventional production route for iron oxide/ chromia catalysts, the solution of the iron and chromium salts used in the precipitation Is often a solution of sulphates. The iron and chromium compounds resulting from the precipitation from such a sulphates solution is often in the form of small acicular crystals. of average length below 500 nm. typically up to about 300 nm. As a result of the need to minimise the amount of sulphur in the final catalyst. extensive washing of the precipitate is often necessary: furthermore, precipitation from sulphates solution often gives rise to a significant proportion of the chromium in hexavalent form in the final catalyst precursor. Not only are hexavalent chromium compounds toxic, thus presenting handling problems. but they give rise to considerable exotherms upon the subsequent reduction of the catalyst precursor. For these reasons, precipitation of the iron and chromium compounds from a solution of iron and chromium nitrates is preferable: as described in US 4 305 846. this not only avoids the Introduction of sulphur compounds. but also minimises the amount of hexavalent chromium compounds in the catalyst precursors However, in contrast to the small acicular crystals formed when using a sulphates solution, the nitrates solution tends to provide the precipitates in the form of an amorphous gel structure.
We have found that suitable precursors can be produced by effecting the precipitation of iron and chromium compounds in the presence of the particles having an aspect ratio of at least 2 and an average length within the range 500 to 1500 nm. Thus particles having the desired structure may be siurried into the solution of the base used to effect the precipitation. While a solution of iron and chromium sulphates may be used for the precipitation. it is preferred to employ a solution of the nitrates. Alternatively, but less preferably the particles may be mixed with the precipitated iron and chromium compounds before calcination thereof
The particles having an aspect ratio of at least 2 may be of iron oxide or of any suitable material, such as alumina or zinc oxide. that is inert under the conditions of use of the catalyst. In particular there may be used acicular alumina particles. e.g. acicular boehmite. or. preferably, acicular iron oxide, or oxyhydroxide. particles. e.g. acicular haematite or goethite particles. Alternatively suitable plate-like iron oxide particles may be maae by rapidiy oxidising ferrous hydroxide. Plate-like aluminium monohydrate (boehmite) particles may also be used. The particles preferably have a BET surface area of at least 5 m2/g. and in particular in the range 8 to 20 m2/g. Where the particles are present during the precipitation stage. at least some of the iron and chromium appears to be precipitated as a coating of the iron and chromium compounds on the particles.
The precursor preferably has an iron oxide content (expressed as Fe2O3) of 60 to 95% by weight. Preferably the iron to chromium atomic ratio in the precursor is in the range 6 to 20, particularly 8 to 12. The precursor may contain oxides of other metals. eg aluminium, manganese, or, especially, copper. Particularly preferred precursors have an iron to copper atomic ratio of 10:1 to 100:1. Such additional oxides may be introduced by coprecipitation of suitable metal compounds that decompose upon heating to the oxides with the iron and chromium compounds. Alternatively, or additionally, such additional oxides may be Incorporated by effecting the precipitation of the iron and chromium compounds in the presence of the desired additional oxides or compounds that decompose to the oxides upon heating. Alternatively, such oxides, or compounds that decompose thereto upon heating, may be added to the precipitated iron and chromium compounds before calcination and shaping into the desired pellets. Alternatively. the precipitated iron and chromium compounds, before or after calcination and forming the shapea pellets. may be impregnated with a solution of compounds that decompose upon heating to the desired additional oxides.
The particles of aspect ratio at least 2 preferably form 2 to 40%. particularly 5 to 30%, by weight of the total weight of the calcined Precursor Where the particles are of a material, e.g. alumina. that does not exert any significant catalytic activity, the particles act as a diluent and so it is preferred that they form less than 20% by weight of the calcined precursor. It is also believed that, even when the particles used in the production of the precursor are iron oxide particles. they exhibit little catalytic activity themselves. The particles are believed to modify advantageously the pore structure of the catalyst obtained by reduction of the precursor, enabling more ready access of the reactants to the catalytically active sites in the catalyst pellets.
As indicated above, after forming the composition containing precipitated iron and chromium compounds and the particles. having an aspect ratio of at least 2. the composition is calcined to convert the precipitated iron and chromium compounds to oxides and then is tableted into suitably sized pellets. Such pellets generally have a maximum and minimum dimensions in the range 2 to 15 mm.
The catalyst pellets formed by the reduction of the precursor pellets are particularly of use for the high temperature shift reaction wherein a feed gas containing carbon monoxide and steam. and often other components such as hydrogen. carbon dioxide. methane. nitrogen. andlor argon. is passed through a bed of the catalyst pellets at an inlet temperature above about 300 C. and usualiy in the range 300-370 C at a pressure. usually in the range from atmospheric to 100 bar abs. The shift reaction is exothermic. and so unless means are provided to effect cooling of the gas as it passes through the catalyst bed, the exit temperature is usuaily in the range 370450 C.
The invention is illustrated by the following examples. In these examples. acicuiar particles were used. The nature and BET surface area of the acicular particles used is set out in the following
Table
Table i
average width BET BET surface Composition form length (nm) (nm) area (m lg) A | Haematite rods 1 900 70-150 9.4 B I Haematite | rods 1 1200 1 200400 ! 3.8 C | Goethite | laths 700 100-200 1 15.8 D : Goethite ! laths , * * * 16.4 E | Goethite j laths 1 700 | 100-200 j 18.8 * not determined. but believed to be similar to C and E.
Example 1 (comparative)
A solution containing iron. chromium. and copper nitrates in the atomic proportions of 90 Fe: 8 Cr: 2 Cu and having a total metals concentration of about 2 M. was added to a near saturated solution of sodium carbonate whiie continuously stirring and maintaining the temperature at about 60 C to precipitate iron. chromium. and copper compounds. Addition of the metals solution was stopped when the pH was about 2.5-3.0. While continuing stirring the slurry was allowed to de-gas and then the pH adjusted to 7.0. The precipitate was filtered off and washed until the sodium content (expressed as Na2O) was below 0.2% by weight. The precipitate was then dried and calcined In air at 1 500C to decompose the Iron. chromium. and copper compounds to the respective oxides. The composition was then tableted into cylindrical catalyst precursor pellets of 5.4 mm diameter and 3.6 mm height of particle density about 2.0 g/cm3
The activity of the catalyst formed by reduction of the precursor was determined by charging about 17 ml of the pellets to a tubular isothermal reactor of internal diameter 27 mm. The precursor was reduced by passing a mixture of equal volumes of process gas and steam through the reactor at a flow rate of 1350 IJhr whiie increasing the temperature to 400"C. The process gas had the following composition (% by volume):
carbon monoxide 4 4 14 carbon dioxide 6.25 nitrogen 25.5
hydrogen 53
methane 1 25 To assess the activity of the resultant catalyst. a mixture of 2 volumes of the above process gas and one volume of steam was then passed througn the catalyst sample and the outlet gas analysed.
The flow rate was varied until the composition of the outlet gas indicated that a specified proportion of carbon monoxide had been converted. The procedure was effected at two temperatures, viz 365"C and 435"C. to simulate typical shift reactor inlet and outlet temperatures.
Examples 2-9 The procedure of Example 1 was repeated except that acicular iron oxide particles were added to the sodium carbonate solution to form a slurry before addition of the mixed metals nitrates solution.
The amounts of the acicuiar particles used were such that the weight of added acicular particles amounted to the percentage of the calcined precursor quoted in Table II below. The activity was determined by reducing the precursor and testing it as in Example 1. As a comparison of the activities at the two temperatures. in Table lIthe ratios of the observed flow rates to those of Example 1 at the respective temperatures are quoted.
Example 10
The procedure of Example 2 was repeated except that the acicuiar material was added after precipitation of the iron, chromium. and copper compounds. but before de-gassing of the precipitate slurry.
Examples 11-12 (comparative)
Pelleted commercially available iron oxide/chromium oxidelcopper oxide high temperature shift catalyst precursors having a similar composition to the precursors of Example 1 but in which the iron oxide was present as small acicular crystals of average length 150 nm (Example 11) and 300 nm (Example 12), possibly as a result of precipitation from a sulphates solution, were reduced and activity tested as in Example 1.
From the following Table II it is seen that the catalysts of the invention. Examples 2-10, all exhibited an increased activity compared to the acicular material-free catalyst of Example 1 and compared to the catalysts of Examples 11 and 12 where the iron oxide was present as small acicular crystals. Whereas the BET surface area of the acicular material-free catalysts of Example 1 (as measured on the catalyst discharged from the activity test). was 16.8 m/g the BET surface areas of the catalysts according to the invention, likewise measured on samples of the catalyst discharged from the activity test, were lower. thus indicating that the increase in activity was not a result of an increase in the BET surface area of the catalyst.
The crush strength of a number of catalyst pellets discharged from the activity test of Examples 1, 2, 5. 6. and 9 was determined by measuring the load. applied to the curved surface of the cylindrical pellets, required to crush the pellet. The crush strength is taken to be the average of the load required for the individual pellets tested of that catalyst sample. In Table II the average strength of the sample is quoted relative to that of the Example 1 pellets. It is seen that the incorporation of the acicular particles gave a significant increase in strength.
No advantage of improved activity was observed when acicular particles were analogously incorporated into copper oxide/zinc oxide/alumina low temperature shift catalyst precursors.
Table II
Acicular material Relative flow rate BET surface Relative crush Ex. area (m/g) strenght type weight+ (%) 365 C 435 C 1 - - 1.00 1.00 16.8 1.0 2 A 16.4 1.39 1.45 12.6 1.8 3 A 11.4 1.20 1.28 14.3 4 A 38.4 0.99 1.12 14.9 5 B 20.7 1.19 1.22 14.4 1.2 6 C 11.3 1.26 1.43 14.8 1.9 7 D 12 1.23 1.24 11.8 8 D 29.9 1.22 1.30 13.5 9 E 16.3 1.20 1.42 13.1 1.9 10 A 20.4 1.08 1.15 - 11 - - 0.94 0.98 - 12 | - - I 0.88 1 0.77 - - based on weight of calcined precursor
of discharged catalyst.
Claims (10)
1. Catalyst precursor pellets compnslng oxides of iron and chromium and including particles having
an aspect ratio of at least 2 and an average (by weight) maximum dimension of at least 500 nm.
2. Catalyst precursor pellets according to claim 1 wherein the particles are selected from alumina.
alumina monohydrate, zinc oxide. iron oxide. and iron oxynydroxide particles.
3. Catalyst precursor pellets according to claim 1 or claim 2 wherein the particles are acicular.
4. Catalyst precursor pellets according to any one of claims 1 to 3 having an iron oxide content
(expressed as Fe,O,) of 60 to 95% by weight.
5 Catalyst precursor peilets according to any one of claims 1 to 4 having an iron to chromium atomic
ratio in the range 6 to 20.
6. Catalyst precursor pellets according to any one of claims 1 to 5 containing oxides of metals
selected from aluminium, manganese. and copper.
Catalyst precursor pellets accoralng to cialm 6 containing copper oxide and having an iron to
copper atomic ratio of 10:1 to 100:1.
8. Catalyst precursor pellets according to any one of claims 1 to 7 containing 2 to 40% by weight of
the acicular particles.
9. A process for the production of catalyst precursor pellets according to any one of claims 1 to 8
comprising precipitating iron and chromium compounds in the presence of acicular particles having
an average length within the range 500 to 1500 nm. calcining the resultant precipitate and forming
the calcined precipitate into pellets.
10. A shift process comprising passing a mixture of carbon monoxide and steam over a catalyst
obtained by reducing catalyst precursor pellets according to any one of claims 1 to 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9506693A GB2288341B (en) | 1994-04-15 | 1995-03-31 | Catalysts |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9407512A GB9407512D0 (en) | 1994-04-15 | 1994-04-15 | Catalysts |
| GB9506693A GB2288341B (en) | 1994-04-15 | 1995-03-31 | Catalysts |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB9506693D0 GB9506693D0 (en) | 1995-05-24 |
| GB2288341A true GB2288341A (en) | 1995-10-18 |
| GB2288341B GB2288341B (en) | 1997-12-10 |
Family
ID=26304711
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9506693A Expired - Lifetime GB2288341B (en) | 1994-04-15 | 1995-03-31 | Catalysts |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2288341B (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2017072481A1 (en) * | 2015-10-29 | 2017-05-04 | Johnson Matthey Public Limited Company | Water-gas shift catalyst |
| US10494255B2 (en) | 2015-10-29 | 2019-12-03 | Johnson Matthey Public Limited Company | Water gas shift process |
| US11014811B2 (en) | 2015-10-29 | 2021-05-25 | Johnson Matthey Public Limited Company | Water gas shift process |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0181999A1 (en) * | 1984-11-22 | 1986-05-28 | Süd-Chemie Ag | Dehydrogenation catalyst |
-
1995
- 1995-03-31 GB GB9506693A patent/GB2288341B/en not_active Expired - Lifetime
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0181999A1 (en) * | 1984-11-22 | 1986-05-28 | Süd-Chemie Ag | Dehydrogenation catalyst |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2017072481A1 (en) * | 2015-10-29 | 2017-05-04 | Johnson Matthey Public Limited Company | Water-gas shift catalyst |
| US10494255B2 (en) | 2015-10-29 | 2019-12-03 | Johnson Matthey Public Limited Company | Water gas shift process |
| AU2016344491B2 (en) * | 2015-10-29 | 2020-05-07 | Johnson Matthey Public Limited Company | Water-gas shift catalyst |
| EA035796B1 (en) * | 2015-10-29 | 2020-08-12 | Джонсон Мэтти Паблик Лимитед Компани | Water-gas shift catalyst |
| US10807866B2 (en) | 2015-10-29 | 2020-10-20 | Johnson Matthey Public Limited Company | Water-gas shift catalyst |
| US11014811B2 (en) | 2015-10-29 | 2021-05-25 | Johnson Matthey Public Limited Company | Water gas shift process |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2288341B (en) | 1997-12-10 |
| GB9506693D0 (en) | 1995-05-24 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 732E | Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977) | ||
| PE20 | Patent expired after termination of 20 years |
Expiry date: 20150330 |