US4301037A
Expired / Lapsed
US
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Extruded alumina catalyst support having controlled distribution of pore sizes
Assignee: WRGRACE & C0 A CORP OF CT
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Filing: 1980-04-01
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Granted: 1981-11-17
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Expires: 2000-04-01
Abstract
Abstract A thermally stable, pure transition alumina extrudate suitable for use as a catalyst support has a uniquely defined bimodal pore size distribution and very good mechanical properties. Most of the surface area is in a micropore region having pores of less than 500 Angstrom units, a pore volume of 0.60 to 0.80 cm.3/g., a narrowly defined effective pore volume distribution within this region and a median pore diameter which can be controlled within the range of 90-210 Angstrom units. The macropore region made of pores having diameters of 1,000- 10,000 Angstrom units has a pore volume of at least 0.10 cm.3/g. These two pore volumes are essentially connected directly to each other. The extrudates can be strengthened by acidic additives and given increased thermal stability by adding rare earth oxides.
Inventors
- 👤 Moises G. Sanchez
- 👤 Jose E. Herrera
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 09:55
CPC Classifications
B; B01; B01J; B01J35/00; B01J35/60; B01J21/00; B01J21/02; B01J21/04; C; C01; C01F; C01F7/00; C01F7/02; C01F7/021; C01F7/025; B01J35/61; B01J35/615; B01J35/63; B01J35/635; B01J35/64; B01J35/647; B01J35/651; B01J35/653; B01J35/66; B01J35/67; B01J35/69; B01J37/00; B01J37/0009; C01P; C01P2004/00; C01P2004/51; C01P2004/54; C01P2004/60; C01P2004/61; C01P2006/00; C01P2006/12; C01P2006/14; C01P2006/16; C01P2006/17; C01P2006/22; Y; Y10; Y10S; Y10S502/00; Y10S502/50; Y10S502/503; Y10S502/504
Claims Analysis
Total Claims: 58
Claim 1
Independent Claim
365 words
A thermally stable, bimodal extrudate consisting essentially of a pure transition alumina suitable for use as a catalyst support having a substantial first micropore volume made of relatively small pores having a pore diameter of less than 500 Angstrom units, a second macropore volume made of relatively large pores with a pore diameter in the range of 1,000 to 10,000 Angstrom units, and with very little intermediate pore volume made of pores with a pore diameter in the range of 500 to 1,000 Angstrom units, said alumina extrudate having a first micropore volume, as measured by mercury porosimetry, having pore diameters of 500 Angstrom units or less, of about 0.60 to about 0.85 cm. 3 /g.; a second macropore volume, as measured by mercury porosimetry having pore diameters in the range of 1,000 to 10,000 Angstrom units, of about 0.10 to less than 0.30 cm. 3 /g.; an intermediate pore volume, as measured by mercury porosimetry, having pore diameters in the range of 500 to 1,000 Angstrom units, of less than about 0.05 cm. 3 /g.; said micropore volume having a median pore diameter of 90-210 Angstrom units and having a relatively narrow effective pore size distribution about the median pore diameter with a value of greater than 0.55 for the uniformity factor, U, given by the formula ##EQU6## where D 50 is the micropore volume median diameter, D 95 is the smallest pore diameter of that fraction of the largest micropores which constitutes 5 percent of the micropore volume, and D 5 is the largest pore diameter of that fraction of the smallest micropores which constitutes 5 percent of the micropore volume; the surface area within said micropore volume being greater than 95 percent of the total surface area measured by nitrogen adsorption; an average crush strength given by the formula ACS>kdD.sup.2 L where ACS is the average crush strength in pounds force, d is the compacted bulk density of the extrudates in pounds per cubic foot, D is the average extrudate diameter in inches, L is the average extrudate length in inches, and k is a factor with a value of at least 90; and an attrition loss of less than 7 percent.
Claim 2
Dependent Claim
365 words
A thermally stable, bimodal extrudate consisting essentially of a pure transition alumina suitable for use as a catalyst support having a substantial first micropore volume made of relatively small pores having a pore diameter of less than 500 Angstrom units, a second macropore volume made of relatively large pores with a pore diameter in the range of 1,000 to 10,000 Angstrom units, and with very little intermediate pore volume made of pores with a pore diameter in the range of 500 to 1,000 Angstrom units, said alumina extrudate having a first micropore volume, as measured by mercury porosimetry, having pore diameters of 500 Angstrom units or less, of about 0.60 to about 0.85 cm. 3 /g.; a second macropore volume, as measured by mercury porosimetry having pore diameters in the range of 1,000 to 10,000 Angstrom units, of about 0.10 to less than 0.30 cm. 3 /g.; an intermediate pore volume, as measured by mercury porosimetry, having pore diameters in the range of 500 to 1,000 Angstrom units, of less than about 0.05 cm. 3 /g.; said micropore volume having a median pore diameter of 90-210 Angstrom units and having a relatively narrow effective pore size distribution about the median pore diameter with a value of greater than 0.55 for the uniformity factor, U, given by the formula ##EQU6## where D 50 is the micropore volume median diameter, D 95 is the smallest pore diameter of that fraction of the largest micropores which constitutes 5 percent of the micropore volume, and D 5 is the largest pore diameter of that fraction of the smallest micropores which constitutes 5 percent of the micropore volume; the surface area within said micropore volume being greater than 95 percent of the total surface area measured by nitrogen adsorption; an average crush strength given by the formula ACS>kdD.sup.2 L where ACS is the average crush strength in pounds force, d is the compacted bulk density of the extrudates in pounds per cubic foot, D is the average extrudate diameter in inches, L is the average extrudate length in inches, and k is a factor with a value of at least 90; and an attrition loss of less than 7 percent.
Claim 3
Dependent Claim
31 words
The alumina extrudate of claim 1, wherein the extrudate has a ratio of average length to average diameter in the range of about 1 to 1 to about 8 to 1.
Claim 4
Dependent Claim
29 words
The alumina extrudate of claim 2, wherein the ratio of average length to average diameter is in the range of about 3 to 2 to about 5 to 1.
Claim 5
Dependent Claim
17 words
The alumina extrudate of claim 2, wherein the average diameter of the extrudate is about 1/16 inch.
Claim 6
Dependent Claim
17 words
The alumina extrudate of claim 2, wherein the average diameter of the extrudate is about 1/8 inch.
Claim 7
Dependent Claim
18 words
The alumina extrudate of claim 2, wherein k in the average crush strength formula is at least 100.
Claim 8
Dependent Claim
18 words
The alumina extrudate of claim 6, wherein k in the average crush strength formula is at least 120.
Claim 9
Dependent Claim
26 words
The alumina extrudate of claim 2, wherein the extrudate has a surface area when measured by the nitrogen BET method of about 80-400 m. 2 /g.
Claim 10
Dependent Claim
26 words
The alumina extrudate of claim 8, wherein the extrudate has a surface area when measured by the nitrogen BET method of about 100-300 m. 2 /g.
Claim 11
Dependent Claim
15 words
The alumina extrudate of claim 2, wherein the uniformity factor, U, is greater than 0.60.
Claim 12
Dependent Claim
15 words
The alumina extrudate of claim 2, wherein the uniformity factor, U is greater than 0.70.
Claim 13
Dependent Claim
23 words
The alumina extrudate of claim 2, wherein the median pore diameter of the micropore volume is from about 100 to 150 Angstrom units.
Claim 14
Dependent Claim
19 words
The alumina extrudate of claim 2, wherein the micropore volume is from about 0.65 to 0.80 cm. 3 /g.
Claim 15
Dependent Claim
30 words
The alumina extrudate of claim 2, wherein the surface area within said micropore volume is greater than 98 percent of the total surface area measured by the nitrogen BET method.
Claim 16
Dependent Claim
18 words
The alumina extrudate of claim 2, wherein the extrudate has an attrition loss of less than 5 percent.
Claim 17
Dependent Claim
19 words
The alumina extrudate of claim 2, wherein the extrudate is made from a crystallographically pure microcrystalline alpha alumina monohydrate.
Claim 18
Dependent Claim
18 words
The alumina extrudate of claim 2, further characterized by having a volume shrinkage of less than 6 percent.
Claim 19
Dependent Claim
14 words
The alumina extrudate of claim 17, wherein the shrinkage is less than 5 percent.
Claim 20
Dependent Claim
18 words
The alumina extrudate of claim 2, further comprising at least one rare earth oxide deposited onto the extrudate.
Claim 21
Dependent Claim
16 words
The alumina extrudate of claim 19, wherein the rare earth oxide comprises at least lanthanum oxide.
Claim 22
Dependent Claim
20 words
The alumina extrudate of claim 20, wherein the rare earth oxide comprises 1-15 weight percent of the total extrudate weight.
Claim 23
Dependent Claim
20 words
The alumina extrudate of claim 21, wherein the rare earth oxide comprises 3-9 weight percent of the total extrudate weight.
Claim 24
Dependent Claim
18 words
The alumina extrudate of claim 2, wherein the intermediate pore volume is less than 0.03 cm. 3 /g.
Claim 25
Dependent Claim
26 words
The alumina extrudate of claim 2, wherein the macropore volume is in the range of from greater than 0.15 to less than 0.25 cm. 3 /g.
Claim 26
Dependent Claim
20 words
The alumina extrudate of claim 2, wherein the compacted bulk density is from 27 to 38 pounds per cubic foot.
Claim 27
Dependent Claim
20 words
The alumina extrudate of claim 2, wherein the total mercury pore volume is from 0.75 to 1.15 cm. 3 /g.
Claim 28
Dependent Claim
20 words
The alumina extrudate of claim 26, wherein the total mercury pore volume is from 0.80 to 1.00 cm. 3 /g.
Claim 29
Dependent Claim
19 words
The alumina extrudate of claim 2, wherein the macromedian pore diameter ranges from about 3,000 to 7,000 Angstrom units.
Claim 30
Dependent Claim
17 words
The alumina extrudate of claim 28, wherein the macromedian pore diameter ranges from about 4,000 to 6,000.
Claim 31
Independent Claim
286 words
A method of producing a bimodal thermally stable, pure transition alumina extrudate suitable for use as a catalyst support having a substantial first micropore volume made of relatively small pores having a pore diameter of less than 500 Angstrom units, a second macropore volume made of relatively large pores with a pore diameter in the range of 1,000 to 10,000 Angstrom units, and with very little intermediate pore volume made of pores with a pore diameter in the range of 500 to 1,000 Angstrom units, said method comprising the steps of (a) forming an aqueous mixture of a microcrystalline alpha alumina monohydrate which is an intermediate between boehmite and pseudoboehmite having a solids content in the range of 32-42 weight percent; (b) mixing the material of step (a) to form a paste for 15 to 300 minutes which renders the paste extrudable; (c) extruding the paste of step (b) to form extrudates having a length to diameter ratio of about 1 to 1 to about 8 to 1; (d) drying the extrudates; and (e) calcining the extrudates at a temperature in the range of 800°-2,000° F. to obtain an alumina extrudate having a first micropore volume, as measured by mercury porosimetry, having pore diameters of 500 Angstrom units or less, of about 0.60 to 0.85 cm. 3 /g.; a second macropore volume, as measured by mercury porosimetry having pore diameters in the range of 1,000 to 10,000 Angstrom units, of about 0.10 to less than 0.30 cm. 3 /g.; an intermediate pore volume, as measured by mercury porosimetry, having pore diameters in the range of 500 to 1,000 Angstrom units, of less than 0.05 cm. 3 /g.; and a median micropore diameter, of 90-210 Angstrom units.
Claim 32
Independent Claim
286 words
A method of producing a bimodal thermally stable, pure transition alumina extrudate suitable for use as a catalyst support having a substantial first micropore volume made of relatively small pores having a pore diameter of less than 500 Angstrom units, a second macropore volume made of relatively large pores with a pore diameter in the range of 1,000 to 10,000 Angstrom units, and with very little intermediate pore volume made of pores with a pore diameter in the range of 500 to 1,000 Angstrom units, said method comprising the steps of (a) forming an aqueous mixture of a microcrystalline alpha alumina monohydrate which is an intermediate between boehmite and pseudoboehmite having a solids content in the range of 32-42 weight percent; (b) mixing the material of step (a) to form a paste for 15 to 300 minutes which renders the paste extrudable; (c) extruding the paste of step (b) to form extrudates having a length to diameter ratio of about 1 to 1 to about 8 to 1; (d) drying the extrudates; and (e) calcining the extrudates at a temperature in the range of 800°-2,000° F. to obtain an alumina extrudate having a first micropore volume, as measured by mercury porosimetry, having pore diameters of 500 Angstrom units or less, of about 0.60 to 0.85 cm. 3 /g.; a second macropore volume, as measured by mercury porosimetry having pore diameters in the range of 1,000 to 10,000 Angstrom units, of about 0.10 to less than 0.30 cm. 3 /g.; an intermediate pore volume, as measured by mercury porosimetry, having pore diameters in the range of 500 to 1,000 Angstrom units, of less than 0.05 cm. 3 /g.; and a median micropore diameter, of 90-210 Angstrom units.
Claim 33
Dependent Claim
24 words
The method according to claim 30, wherein the solids content of step (a) is controlled to be in the range of 35-40 weight percent.
Claim 34
Dependent Claim
34 words
The method according to claim 30, further comprising tumbling the extrudates made in step (c) to round the ends and reduce any edge irregularities so as to render the extrudates less susceptible to attrition.
Claim 35
Dependent Claim
28 words
The method according to claim 30, wherein the length to diameter ratio in step (c) is controlled to be about 3 to 2 to about 5 to 1.
Claim 36
Dependent Claim
31 words
The method according to claim 30, wherein the calcination temperature is controlled to produce an extrudate having a surface area when measured by nitrogen porosimetry of about 80-400 m. 2 /g.
Claim 37
Dependent Claim
25 words
The method according to claim 34, wherein the calcination temperature is controlled to produce an extrudate having a surface area of 100-300 m. 2 /g.
Claim 38
Dependent Claim
28 words
The method according to claim 30, wherein said microcrystalline alpha alumina monohydrate powder is characterized by a d-spacing which ranges from about 6.2 to about 6.5 Angstrom units.
Claim 39
Dependent Claim
32 words
The method according to claim 30, wherein the microcrystalline alpha alumina monohydrate added to the mixture in step (a) comprises a mixture of a dry powder and a washed wet filter cake.
Claim 40
Dependent Claim
26 words
The method according to claim 30, further comprising increasing the thermal stability of the extrudates by depositing at least one rare earth oxide into the extrudates.
Claim 41
Dependent Claim
17 words
The method according to claim 38, wherein the rare earth oxide deposited comprises at least lanthanum oxide.
Claim 42
Dependent Claim
38 words
The method according to claim 30, further comprising adding to the aqueous mixture of step (a) recycled fines of previously formed extrudates which have been calcined at temperatures no higher than the calcination temperature employed in step (e).
Claim 43
Dependent Claim
29 words
The method according to claim 40, wherein the mixture in step (a) comprises recycled fines in an amount up to 15 parts by weight per 100 parts of solids.
Claim 44
Dependent Claim
41 words
The method according to claim 30, wherein the aqueous mixture is formed by initially mixing a fraction of the alpha alumina monohydrate with the total amount of water and then adding the remaining amount of alpha alumina monohydrate with additional mixing.
Claim 45
Dependent Claim
15 words
The method according to claim 42, wherein the first fraction added is about 50 percent.
Claim 46
Dependent Claim
16 words
The method according to claim 42, wherein the first fraction is about 90 to 95 percent.
Claim 47
Dependent Claim
22 words
The method according to claim 30, further comprising adding at least one additive to the mixture before the extrusion in step (c).
Claim 48
Dependent Claim
13 words
The method according to claim 45, wherein the additive is an acidic additive.
Claim 49
Dependent Claim
13 words
The method according to claim 46, wherein the acid additive is aluminum nitrate.
Claim 50
Dependent Claim
25 words
The method according to claim 45, wherein the additive comprises a base selected from the group consisting of aqueous ammonium hydroxide and anhydrous ammonia gas.
Claim 51
Dependent Claim
13 words
The method according to claim 48, wherein the base is aqueous ammonium hydroxide.
Claim 52
Dependent Claim
14 words
The method according to claim 48, wherein the neutralization material is anhydrous ammonia gas.
Claim 53
Independent Claim
20 words
The method according to clai 30, wherein the mixing time in step (b) is from about 15 to 70 minutes.
Claim 54
Independent Claim
20 words
The method according to clai 30, wherein the mixing time in step (b) is from about 15 to 70 minutes.
Claim 55
Dependent Claim
17 words
The method according to claim 30, wherein the drying in step (d) is performed slowly and uniformly.
Claim 56
Dependent Claim
20 words
The method according to claim 52, wherein the drying is performed as the extrudates move continuously through a heating zone.
Claim 57
Dependent Claim
18 words
The method according to claim 30, wherein the calcining in step (e) is done in a rotary calciner.
Claim 58
Dependent Claim
19 words
The method according to claim 54, wherein the calcining in step (e) is done continuously in a rotary calciner.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-11-16 | 1985-05-18 | 1985-11-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-11-16 | 1989-05-18 | 1989-11-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-11-16 | 1993-05-18 | 1993-11-17 | $7700.00 | Window Closed / Lapsed |