Methods for Increasing Polymer Production Rates with Halogenated Hydrocarbon Compounds

Patent metadata

Field	Value
Publication number	US-2017355793-A1
Application number	US-201715497249-A
Country	US
Kind code	A1
Filing date	Apr 26, 2017
Priority date	Jun 9, 2016
Publication date	Dec 14, 2017
Grant date	—

Abstract

Methods for controlling the productivity of an olefin polymer in a polymerization reactor system using a halogenated hydrocarbon compound are disclosed. The productivity of the polymer can be increased via the addition of the halogenated hydrocarbon compound.

First claim

We claim:

1 . A method of controlling a polymerization reaction in a polymerization reactor system, the method comprising:
(i) contacting a transition metal-based catalyst system with an olefin monomer and an optional olefin comonomer in the polymerization reactor system under polymerization conditions to produce an olefin polymer; and (ii) introducing an amount of a halogenated hydrocarbon compound into the polymerization reactor system to increase a productivity of the olefin polymer.

2 . The method of claim 1 , wherein the halogenated hydrocarbon compound comprises a halogenated aromatic compound, a halogenated alkane compound, or a combination thereof.

3 . The method of claim 1 , wherein the transition metal-based catalyst system is a chromium-based catalyst system, a Ziegler-Natta based catalyst system, a metallocene-based catalyst system, or a combination thereof.

4 . The method of claim 1 , wherein the amount of the halogenated hydrocarbon compound introduced into the polymerization reactor system is in a range from about 5 ppm to about 2000 ppm, based on the weight of the halogenated hydrocarbon compound to the weight of contents of the polymerization reactor system.

5 . The method of claim 1 , wherein the polymerization reactor system comprises a slurry reactor, a gas-phase reactor, a solution reactor, or a combination thereof.

6 . The method of claim 1 , wherein:
the polymerization reactor system comprises a single reactor or two reactors; and the halogenated hydrocarbon compound comprises perfluorohexane, hexafluorobenzene, or both.

7 . The method of claim 1 , wherein the transition metal-based catalyst system is contacted with ethylene and an olefin comonomer comprising a C 3 -C 10 alpha-olefin.

8 . The method of claim 1 , further comprising measuring the productivity, and adjusting the amount of the halogenated hydrocarbon compound introduced into the polymerization reactor system based on the difference between the measured productivity and a target productivity.

9 . The method of claim 1 , wherein the amount of the halogenated hydrocarbon compound introduced into the polymerization reactor system is in a range from about 0.01:1 to about 50:1, based on the weight of the halogenated hydrocarbon compound to the weight of transition metal-based catalyst system.

10 . The method of claim 1 , further comprising a step of adding hydrogen to the polymerization reactor system to increase the melt index (MI) of the olefin polymer, reduce the weight-average molecular weight (Mw) of the olefin polymer, or both.

11 . The method of claim 1 , wherein the introduction of the halogenated hydrocarbon compound into the polymerization reactor system increases the productivity of the olefin polymer by from about 5% to about 350%.

12 . The method of claim 1 , wherein the introduction of the halogenated hydrocarbon compound into the polymerization reactor system decreases the weight-average molecular weight (Mw) of the olefin polymer, decreases the zero-shear viscosity of the olefin polymer, or both.

13 . A process for producing an olefin polymer at a target productivity, the process comprising:
(a) contacting a transition metal-based catalyst system with an olefin monomer and an optional olefin comonomer in a polymerization reactor system under polymerization conditions; and (b) controlling an amount of a halogenated hydrocarbon compound introduced into the polymerization reactor system to produce the olefin polymer at the target productivity.

14 . The process of claim 13 , wherein the productivity of the olefin polymer increases as the amount of the halogenated hydrocarbon compound added to the polymerization reactor system increases.

15 . The process of claim 13 , wherein the Mw and zero-shear viscosity of the olefin polymer decrease as the amount of the halogenated hydrocarbon compound added to the polymerization reactor system increases.

16 . The process of claim 13 , wherein:
the halogenated hydrocarbon compound comprises a halogenated aromatic compound, a halogenated alkane compound, or a combination thereof; and the olefin polymer comprises an ethylene homopolymer, an ethylene/1-butene copolymer, an ethylene/1-hexene copolymer, or an ethylene/1-octene copolymer.

17 . The process of claim 13 , wherein:
the transition metal-based catalyst system comprises one or two metallocene compounds; and the polymerization reactor system comprises a loop slurry reactor.

18 . The process of claim 13 , wherein:
the transition metal-based catalyst system is a chromium-based catalyst system or a Ziegler-Natta based catalyst system; and the polymerization reactor system comprises a loop slurry reactor.

19 . The process of claim 13 , wherein:
the amount of the halogenated hydrocarbon compound introduced into the polymerization reactor system is in a range from about 5 ppm to about 2000 ppm, based on the weight of the halogenated hydrocarbon compound to the weight of contents of the polymerization reactor system; or the amount of the halogenated hydrocarbon compound introduced into the polymerization reactor system is in a range from about 0.2:1 to about 8:1, based on the weight of the halogenated hydrocarbon compound to the weight of transition metal-based catalyst system; or both.

20 . An olefin polymerization process, the process comprising:
contacting a transition metal-based catalyst system with an olefin monomer and an optional olefin comonomer in a polymerization reactor system under polymerization conditions, and in the presence of a halogenated hydrocarbon compound, to produce an olefin polymer; wherein: a productivity of the olefin polymer is greater than that obtained under the same polymerization conditions without the halogenated hydrocarbon compound.

21 . The process of claim 20 , wherein the productivity of the olefin polymer is greater by from about 20% to about 250%.

22 . The process of claim 20 , wherein:
the halogenated hydrocarbon compound has a boiling point in a range from 25° C. to 100° C.; the halogenated hydrocarbon compound is a liquid under the polymerization conditions in the polymerization reactor system; the halogenated hydrocarbon compound is miscible with or soluble in a C 3 to C 10 hydrocarbon solvent; or any combination thereof.

23 . The process of claim 20 , wherein the halogenated hydrocarbon compound comprises perfluorohexane, hexafluorobenzene, or both.

Assignees

• Chevron Phillips Chemical Co Lp

Inventors

• Ding Errun
• Beaulieu William B

Classifications

• C08F2/01 Primary

  characterised by special features of the polymerisation apparatus used · CPC title

• B01J2219/24

  Stationary reactors without moving elements inside · CPC title

• C08F110/14 Primary

  Monomers containing five or more carbon atoms · CPC title

• B01J19/06

  Solidifying liquids (making microcapsules B01J13/02) · CPC title

• B01J19/246

  internally, i.e. the mixture circulating inside the vessel such that the upward stream is separated physically from the downward stream(s) · CPC title