Particle size control of silyl chromate catalysts and uses thereof in fluidized bed reactors

Patent metadata

Field	Value
Publication number	US-12565545-B2
Application number	US-202418914375-A
Country	US
Kind code	B2
Filing date	Oct 14, 2024
Priority date	Jan 23, 2024
Publication date	Mar 3, 2026
Grant date	Mar 3, 2026

Abstract

Supported chromium (VI) catalysts containing a solid oxide, 0.05 to 5 wt. % chromium, and 0.2 to 20 wt. % carbon, in which the solid oxide or the catalyst has a particle size span from 0.5 to 1.4, less than 3 wt. % has a particle size greater than 100 μm, and less than 10 wt. % has a particle size less than 10 μm, can be contacted with an olefin monomer in a fluidized bed reactor or other suitable polymerization reactor to produce an olefin polymer. Representative ethylene-based polymers produced using the chromium catalysts have a HLMI of 4 to 70 g/10 min, a density from 0.93 to 0.96 g/cm 3 , from 150 to 680 ppm solid oxide (such as silica), from 0.5 to 3 ppm chromium, and a film gel count of less than 15 catalyst particle gels per ft 2 of 25 micron thick film and/or a gel count of less than or equal to 50 catalyst particles of greater than 100 μm (in diameter) per five grams of the ethylene polymer.

First claim

We claim:

1 . A supported chromium (VI) catalyst comprising:
a solid oxide comprising silica-coated alumina; and from 0.05 to 5 wt. % chromium, wherein the chromium has at least one triphenylsilyl ligand; wherein the solid oxide or the catalyst is characterized by: an average sphericity in a range from 0.5 to 1.0; a wet particle density in a range from 1.05 to 2.0 g/cc; and (A) an amount of the solid oxide or the catalyst with a particle size greater than 100 μm of less than or equal to 3 wt. %, and a particle size span ((d90-d10)/d50) in a range from 0.5 to 1.4; or (B) an amount of the solid oxide or the catalyst with a particle size greater than 100 μm of less than or equal to 0.5 wt. %, and an amount of the solid oxide or the catalyst with a particle size less than 10 μm of less than or equal to 10 wt. %; or both (A) and (B).

2 . The catalyst of claim 1 , wherein the catalyst is treated with an organoaluminium compound at a molar ratio of aluminum to chromium of from 1:1 to 10:1.

3 . The catalyst of claim 2 , wherein:
the catalyst comprises from 0.1 to 0.4 wt. % chromium; the organoaluminium compound comprises diethylaluminum ethoxide; and the molar ratio of aluminum to chromium is from 2:1 to 5:1.

4 . The catalyst of claim 1 , wherein the silica-coated alumina has an alumina content from 5 wt. % to 95 wt. %.

5 . The catalyst of claim 1 , wherein the silica-coated alumina has an alumina content from 60 wt. % to 90 wt. %.

6 . The catalyst of claim 1 , wherein the average sphericity of the catalyst is in a range from 0.7 to 1.0.

7 . A polymerization process comprising contacting the supported chromium catalyst of claim 1 and an optional co-catalyst with an olefin monomer and an optional olefin comonomer in a polymerization reactor system comprising a fluidized bed reactor under polymerization conditions to produce an olefin polymer.

8 . The process of claim 7 , wherein a linear velocity of a fluidizing gas stream in the fluidized bed reactor is in a range from 0.05 to 0.35 ft/sec.

9 . A supported chromium (VI) catalyst comprising:
a solid oxide comprising silica-coated alumina; from 0.05 to 5 wt. % chromium; and from 0.2 to 20 wt. % carbon; wherein the solid oxide or the catalyst is characterized by: an average sphericity in a range from 0.5 to 1.0; a wet particle density in a range from 1.05 to 2.0 g/cc; and (A) an amount of the solid oxide or the catalyst with a particle size greater than 100 μm of less than or equal to 3 wt. %, and a particle size span ((d90-d10)/d50) in a range from 0.5 to 1.4; or (B) an amount of the solid oxide or the catalyst with a particle size greater than 100 μm of less than or equal to 0.5 wt. %, and an amount of the solid oxide or the catalyst with a particle size less than 10 μm of less than or equal to 10 wt. %; or both (A) and (B).

10 . The catalyst of claim 1 , wherein:
the amount of the catalyst with a particle size greater than 100 μm is less than or equal to 2 wt. %; and the particle size span ((d90-d10)/d50) is in a range from 0.7 to 1.35.

11 . The catalyst of claim 1 , wherein:
the amount of the catalyst with a particle size greater than 100 μm is less than or equal to 0.35 wt. %; and the amount of the catalyst with a particle size less than 10 μm is less than or equal to 5 wt. %.

12 . The catalyst of claim 1 , wherein the catalyst comprises from 0.1 to 0.4 wt. % chromium.

13 . The catalyst of claim 12 , wherein at least 75 wt. % of the chromium is present in an oxidation state of six (Cr+6).

14 . The catalyst of claim 1 , wherein the catalyst has:
a total pore volume from 0.5 to 5 mL/g; and a BET surface area from 200 to 700 m 2 /g.

15 . The catalyst of claim 1 , wherein a number of catalyst particles with a particle size greater than 75 μm is less than or equal to 10,000 per gram of the catalyst.

16 . The catalyst of claim 1 , wherein the catalyst has a d50 average particle size from 15 to 50 μm.

17 . The process of claim 8 , wherein the olefin polymer comprises an ethylene polymer having:
a high load melt index (HLMI) in a range from 4 to 70 g/10 min; a density in a range from 0.93 to 0.96 g/cm 3 ; and a film gel count of less than or equal to 15 catalyst particle gels per ft 2 of 25 micron thick film, wherein film gels encompass a size in diameter of greater than 200 μm caused by the catalyst particles; and/or a gel count of less than or equal to 50 catalyst particles of greater than 100 μm in diameter per 5 grams of the ethylene polymer; wherein the ethylene polymer contains from 150 to 680 ppm solid oxide and from 0.5 to 3 ppm chromium.

18 . The catalyst of claim 9 , wherein the catalyst comprises from 0.5 to 8 wt. % carbon, and the silica-coated alumina has an alumina content from 60 wt. % to 90 wt. %.

19 . The catalyst of claim 9 , wherein the catalyst comprises from 0.1 to 0.4 wt. % chromium.

20 . The catalyst of claim 19 , wherein at least 85 wt. % of the chromium is present in an oxidation state of six (Cr+6).

Assignees

• Chevron Phillips Chemical Co Lp

Inventors

• Mcdaniel Max P
• Schwerdtfeger Eric D
• Lowell Jeffrey S
• Kufeld Scott E

Classifications

• C08F10/02 Primary

  Ethene · CPC title

• C08F4/025

  Metal oxides · CPC title

• C08F4/78 Primary

  selected from chromium, molybdenum or tungsten · CPC title