Continuous Catalyst Activator

• US 20120108768A1
• Filed: 01/05/2012
• Published: 05/03/2012
• Est. Priority Date: 12/20/2007
• Status: Active Grant

• Current Assignee: Chevron Phillips Chemical Company LP (Chevron Corp.)
• Original Assignee: Chevron Phillips Chemical Company LP (Chevron Corp.)
• Inventors: BENHAM, Elizabeth A., MCDANIEL, Max P., STAFFIN, H. Kenneth, CYMBALUK, Ted H., NEWSOME, Charles K., NEASE, Charles R., PARR, Thomas R.
• Granted Patent: US 8,349,264 B2
• Time in Patent Office: Days
• US Class Current: 526/90
• CPC Class Codes: B01J 19/0033 Optimalisation processes, i.e. processes with adaptive control systems adaptive control systems per se G05B13/00
• CPC Class Codes: B01J 2208/0084 inside the bed, e.g. baffles
• CPC Class Codes: B01J 23/26 Chromium
• CPC Class Codes: B01J 23/92 of catalysts comprising metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
• CPC Class Codes: B01J 35/40 characterised by dimensions, e.g. grain size in a colloidal state B01J35/23; crystallite size B01J35/77
• CPC Class Codes: B01J 35/615 100-500 m2/g
• CPC Class Codes: B01J 35/617 500-1000 m2/g
• CPC Class Codes: B01J 35/635 0.5-1.0 ml/g
• CPC Class Codes: B01J 35/638 more than 1.0 ml/g
• CPC Class Codes: B01J 37/08 Heat treatment B01J37/0009, B01J37/0018 take precedence
• CPC Class Codes: B01J 37/16 Reducing
• CPC Class Codes: B01J 38/10 using elemental hydrogen
• CPC Class Codes: B01J 38/30 in gaseous suspension, e.g. fluidised bed
• CPC Class Codes: B01J 8/006 by filtration
• CPC Class Codes: B01J 8/26 with two or more fluidised beds, e.g. reactor and regeneration installations
• CPC Class Codes: B01J 8/36 with fluidised bed through which there is an essentially horizontal flow of particles
• CPC Class Codes: C08F 10/00 Homopolymers and copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
• CPC Class Codes: C08F 210/14 Monomers containing five or more carbon atoms
• CPC Class Codes: C08F 210/16 Copolymers of ethene with alpha-alkenes, e.g. EP rubbers
• CPC Class Codes: C08F 2500/12 Melt flow index or melt flow ratio
• CPC Class Codes: C08F 4/24 : Oxides
• CPC Class Codes: Y02P 20/584 : Recycling of catalysts

Abstract

Methods and systems for preparing catalyst, such as chromium catalysts, are provided. The valence of at least a portion of the catalyst sent to an activator is changed from Cr(III) to Cr(VI). The catalyst is prepared or activated continuously using a fluidization bed catalyst activator.

Claims

1. A method comprising:

(a) introducing a catalyst comprising chromium into a continuous catalyst activator;

(b) introducing a fluidizing gas into the continuous catalyst activator comprising a fluidized bed of the catalyst;

(c) heating the catalyst within the continuous catalyst activator while maintaining flow of the catalyst through the continuous catalyst activator such that the catalyst is maintained at a hold temperature for an average hold time; and

(d) contacting the catalyst with at least one agent to convert at least a portion of the chromium from Cr(III) to Cr(VI) to produce a valence-converted catalyst.

2. The method of claim 1 further comprising recycling a filtered portion of the valence-converted catalyst back to an upstream location within the continuous catalyst activator so that essentially no normally detectable amount of catalyst is lost overhead.

3. The method of claim 1 further comprising:

(e) cooling the valence-converted catalyst in a presence of a first oxygenating agent in a separate cooling system downstream of the fluidized bed catalyst activator; and

(f) purging the valence-converted catalyst in a presence of a first inert agent in the separate cooling system.

4. The method of claim 1 further comprising discharging the valence-converted catalyst from the continuous catalyst activator.

5. The method of claim 1 further comprising:

(e) introducing the valence-converted catalyst into a polymerization reactor system, or a combination of polymerization reactors.

6. The method of claim 5 further comprising:

(f) polymerizing a polyolefin product with the valence-converted catalyst, wherein the valence-converted catalyst is reduced in conjunction with the polymerizing.

7. The method of claim 6 further comprising:

(g) monitoring a process variable associated with polymerizing the polyolefin product;

(h) comparing the process variable with a process variable set point; and

(i) adjusting a process variable of the continuous catalyst activator based upon a comparison of the process variable and the process variable set point.

8. The method of claim 1 further comprising controlling a continuous catalyst activator discharge process variable by adjusting a continuous catalyst activator inlet process variable.

9. The method of claim 8, wherein the continuous catalyst activator discharge process variable is a conversion of Cr(III) to Cr(VI), conversion of Cr(VI) to Cr(II), a catalyst color, a catalyst activity, or combinations thereof

10. The method of claim 8, wherein the continuous catalyst activator inlet process variable is a catalyst feedrate, a zone temperature, a catalyst residence time, an average catalyst hold time at a hold temperature, a fluidization gas flow rate, a fluidization bed height, or combinations thereof

11. The method of claim 1, wherein the hold temperature is from about 300°

C. to about 1000°

C. and the average hold time at the hold temperature is from about 1 minute to about 30 hours.

12. The method of claim 1 further comprising titanating the catalyst.

13. The method of claim 1 further comprising reducing at least a portion of the valence-converted catalyst from the Cr(VI) state to a Cr(II) state.

14. The method of claim 13 further comprising reoxidizing at least a portion of the valence-converted catalyst in the Cr(II) state to the Cr(VI) state.

15. The method of claim 1 further comprising discharging at least 2 different valence converted catalysts from the continuous catalyst activator.

16. The method of claim 1, wherein the continuous catalyst activator comprises:

(i) a gas distributor plate extending substantially horizontal within the fluidized bed vessel being arranged to allow passage of a fluidizing gas throughout the fluidized bed vessel;

(ii) an inlet for introducing a catalyst into the fluidized bed vessel;

(iii) at least one zone dividing wall for dividing the fluidized bed vessel into a plurality of zones, at least one of the zone dividing walls comprising a zone opening that allows the catalyst to be introduced into a next downstream zone, the plurality of zones being located substantially horizontal in relation to one another; and

(iv) each zone comprising at least one baffle, each baffle defining a stage, each zone comprising a lower boundary that comprises at least a portion of the gas distributor plate.

17. The method of claim 1, wherein the continuous catalyst activator comprises sufficient baffles to cause an essentially plug flow profile through the fluidized bed vessel.

18. A method comprising:

(a) monitoring a polymerization reactor process variable;

(b) comparing the polymerization reactor process variable with a reactor process variable set point; and

(c) adjusting a continuous catalyst activator process variable based upon a comparison of the polymerization reactor process variable and the reactor process variable set point.

19. The method of claim 18, wherein the continuous catalyst activator process variable is a catalyst feedrate, a zone temperature, a catalyst residence time, an average catalyst hold time at a hold temperature, a fluidization gas flow rate, a fluidization bed height, or combinations thereof.

20. The method of claim 18, wherein adjusting the continuous catalyst activator process variable comprises using a controller programmed with an algorithm comprising neural network, partial least squares, principle, component regression, first principles models, or combinations thereof to infer impending changes in the discharge process stream.