A process and apparatus for in-line blending of polymers

Patent metadata

Field	Value
Publication number	US-2018371201-A1
Application number	US-201616065066-A
Country	US
Kind code	A1
Filing date	Dec 21, 2016
Priority date	Dec 21, 2015
Publication date	Dec 27, 2018
Grant date	—

Abstract

The present invention deals with a process for polymerising olefins in a solution and withdrawing a stream of the solution from the polymerisation reactor and passing it to a sequence of heating steps. The heated solution is passed to a separation step, which is conducted at a pressure of no more than 15 bar and in which separation step a liquid phase comprising the polymer and a vapour phase coexist. A vapour stream and a concentrated solution stream comprising the polymer are withdrawn from the separation step. At least a part of the vapour stream is passed to the first polymerisation reactor, to the second polymerisation reactor or to both.

First claim

1 .- 14 . (canceled)

15 . A process for producing a polymer composition comprising the steps of:
(A) polymerising, in a first polymerisation reactor in a first solvent,
first olefin monomer having two or more carbon atoms and
optionally a first alpha-olefin comonomer containing from 3 to 10 carbon atoms,
in the presence of a first polymerisation catalyst and optionally a chain transfer agent for producing a first solution comprising a first polymer of first olefin monomer and the optional first alpha-olefin comonomer and the first solvent;
(B) polymerising, in a second polymerisation reactor in a second solvent,
second olefin monomer having two or more carbon atoms and
optionally a second alpha-olefin comonomer containing from 3 to 10 carbon atoms
in the presence of a second polymerisation catalyst and optionally a chain transfer agent for producing a second solution comprising a second copolymer of second olefin monomer and the optional second alpha-olefin comonomer and the second solvent;
(C) withdrawing a first stream of the first solution from the first polymerisation reactor; (D) withdrawing a second stream of the second solution from the second polymerisation reactor; (E) combining the second stream of the second solution with the first stream of the first solution to produce a combined stream of the first and second solution; (F) passing the combined stream of the first and second solution to a first heating step and a second heating step; (G) passing the combined stream of the first and second solution into a separation step, which separation step is conducted at a pressure of no more than 15 bar and in which separation step a liquid phase comprising the polymer and a vapour phase coexist; (H) withdrawing a vapour stream and a concentrated solution stream comprising the polymer from the separation step; and (I) passing at least a part of the vapour stream to the first polymerisation reactor, to the second polymerisation reactor or to both.

16 . The process according to claim 15 comprising the additional step of passing the first stream of the first solution through a static mixer downstream of the second heating step.

17 . The process according to claim 15 comprising the steps of passing the vapour stream to the condensing step; withdrawing a partially condensed vapour stream from the condensing step.

18 . The process according to claim 17 comprising the steps of: passing at least a part of the vapour stream to the first heating step for heating the first stream of the first solution; and recovering the at least part of the vapour stream from the first heating step as the partially condensed vapour stream.

19 . The process according to claim 18 comprising the steps of: dividing the vapour stream into a first vapour stream and a second vapour stream; passing the first vapour stream to the first heating step for heating the first stream of the first solution and recovering the first vapour stream from the first heating step; passing the second vapour stream to the third heating step for heating the second stream of the second solution and recovering the second vapour stream from the third heating step; and combining the first and the second vapour streams downstream the first and the third heating steps.

20 . The process according to claim 19 comprising the step of dividing the partially condensed vapour stream into a condensed vapour stream and an uncondensed vapour stream.

21 . The process according to claim 20 comprising the step of passing the condensed vapour stream to the first polymerisation reactor, to the second polymerisation reactor or to both the first polymerisation reactor and the second polymerisation reactor.

22 . The process according to claim 21 comprising the step of passing at least a part of the uncondensed vapour stream to the first polymerisation reactor or to the second polymerisation reactor.

23 . The process according to claim 15 wherein the first solvent and the second solvent are the same.

24 . The process according to claim 15 wherein the first olefin monomer and the second olefin monomer are ethylene or propylene.

25 . The process according to claim 15 wherein the second alpha-olefin comonomer is the same as the first alpha-olefin comonomer.

26 . The process according to claim 15 wherein the first co-monomer has a boiling point which is less than the boiling point of the first solvent and the second co-monomer has a boiling point which is greater than the boiling point of the second solvent.

27 . The process according to claim 15 wherein the polymer content in solution stream withdrawn from the first flashing stage is from 40 to 90% by weight, preferably from 50 to 80% by weight, and most preferably from 60 to 75% by weight, based on the total weight content of the solution stream.

28 . A process for producing a polymer composition comprising the steps of:
(A′) polymerising, in a first polymerisation reactor in a first solvent, first olefin monomer having two or more carbon atoms and optionally a first alpha-olefin comonomer containing from 3 to 10 carbon atoms, in the presence of a first polymerisation catalyst and optionally a chain transfer agent for producing a first solution comprising a first polymer of first olefin monomer and the optional first alpha-olefin comonomer and the first solvent; (B′) polymerising, in a second polymerisation reactor in a second solvent, second olefin monomer having two or more carbon atoms and optionally a second alpha-olefin comonomer containing from 3 to 10 carbon atoms in the presence of a second polymerisation catalyst and optionally a chain transfer agent for producing a second solution comprising a second copolymer of second olefin monomer and the optional second alpha-olefin comonomer and the second solvent; (C′) withdrawing a first stream of the first solution from the first polymerisation reactor and passing it to a first heating step and a second heating step; (D′) withdrawing a second stream of the second solution from the second polymerisation reactor and passing it to a third heating step and a fourth heating step; (E′) combining the heated second stream of the second solution with the heated first stream of the first solution to produce a combined stream of the first and second solution; (F′) passing the combined stream of the first and second solution into a separation step, which separation step is conducted at a pressure of no more than 15 bar and in which separation step a liquid phase comprising the polymer and a vapour phase coexist; (G′) withdrawing a vapour stream and a concentrated solution stream comprising the polymer from the separation step; and (H′) passing at least a part of the vapour stream to the first polymerisation reactor, to the second polymerisation reactor or to both.

29 . The process according to claim 28 comprising the additional step of passing the first stream of the first solution through a static mixer downstream of the second heating step.

30 . The process according to claim 28 comprising the steps of passing the vapour stream to the condensing step; withdrawing a partially condensed vapour stream from the condensing step.

31 . The process according to claim 30 comprising the steps of: passing at least a part of the vapour stream to the first heating step for heating the first stream of the first solution; and recovering the at least part of the vapour stream from the first heating step as the partially condensed vapour stream.

32 . The process according t

Assignees

• Borealis Ag

Inventors

• Al-Haj Ali Mohammad
• Bergstra Michiel
• Eriksson Erik
• Mathivanan Guhan
• Räsänen Jukka
• Sleijster Henry
• Vijay Sameer
• Wurnitsch Christof
• Zitting Samuli
• Kanellopoulos Vasileios
• Aho Jani

Classifications

• C08F6/12

  Separation of polymers from solutions · CPC title

• C08F6/003

  from polymer solutions, suspensions, dispersions or emulsions without recovery of the polymer therefrom · CPC title

• Y02P20/582

  Recycling of unreacted starting or intermediate materials · CPC title

• C08F2/06

  Organic solvent · CPC title

• C08F2/001 Primary

  Multistage polymerisation processes characterised by a change in reactor conditions without deactivating the intermediate polymer (C08F295/00, C08F297/00 take precedence) · CPC title