# US 11,299,568 B2 · Polyolefin production with chromium-based catalysts

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- Number: US 11,299,568 B2
- Document ID: US11299568B2
- Status: Granted
- Kind: B2
- Application number: 17/093,887
- Filed: 2020-11-10
- Published: 2021-02-25
- Granted: 2022-04-12
- Earliest claimed: 2014-09-02
- Assignees: Univation Technologies, LLC
- Applicants: Univation Technologies, LLC
- Inventors: John H. Moorhouse; Kevin J. Cann; Mark G. Goode; Kevin R. Gross
- Web page: https://patentgrep.com/patent/US11299568B2

## CPC

- C08F 210/16: Copolymers of ethene with alpha-alkenes, e.g. EP rubbers
- B01J 4/002: {Nozzle-type elements (nozzle-type reactors B01J19/26)}
- B01J 19/18: Stationary reactors having moving elements inside (B01J19/08, B01J19/26 take precedence)
- B01J 2204/002: the feeding side being of particular interest
- B01J 2219/00063: of the reactants
- B01J 2219/00094: Jackets
- B01J 2219/00168: controlling the viscosity
- B01J 2219/00189: controlling the stirring velocity
- C08F 2410/06: Catalyst characterized by its size
- C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS

## Abstract

A system and method for charging a chromium-based catalyst to a mix vessel; introducing a reducing agent through an entrance arrangement into the mix vessel, and agitating a mixture of the chromium-based catalyst, the reducing agent, and a solvent in the mix vessel to promote contact of the reducing agent with the chromium-based catalyst to give a reduced chromium-based catalyst.

## Claims

### Claim 1

A method of treating a chromium-based catalyst for polyolefin production, the method comprising:
adding a charge of chromium-based catalyst to a mix vessel;
introducing a reducing agent into the mix vessel through a conduit extension that extends at least 0.5 inch into the mix vessel and terminates in a designated vapor space of the mix vessel;
directing the reducing agent toward a location of a mixture level in a range of 20% to 80% of a perpendicular distance from a vertical centerline of the mix vessel to an inside surface of a wall of the mix vessel to give a desired flow index response from the reduced chromium-based catalyst; and
agitating a mixture of the chromium-based catalyst, reducing agent, and a solvent in the mix vessel to disperse the reducing agent in the mixture to promote reaction of the reducing agent with the chromium-based catalyst to give a reduced chromium-based catalyst.

### Claim 2 (depends on 1)

The method of claim 1, wherein the conduit extension is an insert through a nozzle of the mix vessel.

### Claim 3 (depends on 1)

The method of claim 1, wherein the conduit extension directs the reducing agent toward a surface of the mixture level in the mix vessel.

### Claim 4 (depends on 1)

The method of claim 1, wherein the chromium-based catalyst comprises an activated chromium-based catalyst on an unmilled support, and wherein the reducing agent comprises an organoaluminum compound.

### Claim 5 (depends on 1)

The method of claim 1, comprising polymerizing an olefin into a polyolefin in presence of the reduced chromium-based catalyst in a polymerization reactor.

### Claim 6 (depends on 1)

The method of claim 1, wherein the chromium-based catalyst comprises an inorganic oxide support having a pore volume of about 0.5 to about 6.0 cubic centimeters (cm3)/gram (g) and a surface area of about 200 to about 600 square meters (m2)/g.

### Claim 7 (depends on 1)

The method of claim 1, comprising maintaining a level of the mixture in the mix vessel at an impeller region of a shaft of an agitator of the mix vessel.