Polymerization process

Patent metadata

Field	Value
Publication number	US-9540467-B2
Application number	US-201314909505-A
Country	US
Kind code	B2
Filing date	Aug 14, 2013
Priority date	Aug 14, 2013
Publication date	Jan 10, 2017
Grant date	Jan 10, 2017

Abstract

Process for introducing a fresh feed of fresh comonomer and/or fresh inert hydrocarbon to a polymerization reactor which is part of a polymerization process having high and low pressure recovery systems, the high pressure recovery system being at a pressure of 0.5 MPa (5 bar) or above and the low pressure recovery system being at a pressure of less than 0.5 MPa (5 bar). The process includes passing the fresh feed and a process stream containing a first component of hydrogen, nitrogen and/or methane and a second component of a monomer to a separator which is part of the low pressure recovery system and is at a pressure of 0.4 MPa or less to produce a first stream containing a majority of the first component and a second stream containing the second component and a majority of the fresh feed, and passing the second stream to the polymerization reactor.

First claim

The invention claimed is:

1. A process for the introduction of a fresh feed selected from fresh comonomer and fresh inert hydrocarbon to a polymerisation reactor wherein the polymerisation reactor is part of a polymerisation process comprising high and low pressure recovery systems, said high pressure recovery system being at a pressure of 0.5 MPa (5 bar) or above and said low pressure recovery system being at a pressure of less than 0.5 MPa (5 bar), which process comprises passing said fresh feed and a process stream comprising a first component selected from hydrogen, nitrogen and methane and a second component which is a monomer to a separator which is part of the low pressure recovery system and is at a pressure of 0.4 MPa or less to produce a first stream comprising the majority of the first component and a second stream comprising the second component and the majority of the fresh feed, and passing the second stream to the polymerisation reactor.

2. A process according to claim 1 where the fresh feed is fresh comonomer.

3. A process according to claim 1 where the separator is a single stage separation vessel.

4. A process according to claim 1 wherein the polymerisation reactor is a slurry phase reactor and the fresh inert hydrocarbon is a component which is utilised as a diluent in the process.

5. A process according to claim 1 wherein both fresh comonomer and fresh inert hydrocarbon are passed to the separator with the process stream.

6. A process according to claim 1 where the separator is at a temperature of less than 0° C. and/or where the separator is at a pressure of 0.3 MPa or less.

7. A process according to claim 6 where the separator is at a temperature of less than −20° C. and/or where the separator is at a pressure of 0.2 MPa or less.

8. A process according to claim 1 wherein the majority of fresh comonomer passed to the reactor is passed via the claimed process and/or the majority of fresh inert hydrocarbon passed to the reactor is passed via the claimed process.

9. A process according to claim 8 wherein all of the fresh comonomer passed to the reactor is passed via the claimed process.

10. A process according to claim 1 wherein the polymerisation process comprises the steps of:
1) Polymerising a monomer and a comonomer in a polymerisation reactor,
2) Withdrawing an effluent stream comprising solid polymer and a mixture comprising unreacted monomer and unreacted comonomer, and passing the effluent to a high pressure recovery system comprising
a. a high pressure separation step for separating a vapour comprising unreacted monomer and unreacted comonomer from said solids, and
b. a recycle system for recycling at least a portion of the vapour to the polymerisation reactor,

3) Passing the solids from the high pressure recovery system to a low pressure recovery system comprising
a. a low pressure separation step for separating further unreacted monomer and unreacted comonomer from said solids, and
b. a recycle system comprising a vapour/liquid separator for recycling at least a portion of the unreacted monomer and unreacted comonomer,

said separator to which the fresh feed is passed being the “vapour/liquid separator” of step 3(b).

11. A process according to claim 10 wherein a portion of the vapour recovered in step 2(a) is condensed, let-down in pressure, and also passed to the vapour/liquid separator of step 3(b).

12. A process according to claim 10 wherein the polymerisation reactor has a volume of at least 50 m 3 .

13. A process according to claim 1 wherein the polymerisation reactor has a volume of at least 50 m 3 .

14. A process according to claim 1 wherein less than 50 wt % of the second component (monomer) is recovered in the second stream.

15. A process for the treatment of a fresh feed stream to be introduced into a polymerisation reactor, said process comprising
a) Passing the fresh feed stream to a first treatment step where it is treated to remove one or more impurities, and
b) Passing the fresh feed stream exiting the first treatment step with a process stream comprising a first component selected from hydrogen, nitrogen and methane and a second component which is a monomer to a second treatment step which is a separator which is at a pressure of 0.4 MPa (4 bar) or less to produce a first stream comprising the majority of the first component and a second stream comprising the second component and the majority of the fresh feed, and
c) Passing the second stream to the polymerisation reactor.

16. A process according to claim 15 wherein the fresh feed comprises inert hydrocarbon or comonomer.

17. A process according to claim 15 wherein the polymerisation reactor is a slurry loop polymerisation reactor to which inert hydrocarbon is fed as a diluent.

18. A process according to claim 15 wherein the polymerisation reactor is part of a polymerisation process comprising high and low pressure recovery systems, said high pressure recovery system being at pressure of 0.5 MPa or above and said low pressure recovery system being at pressure of less than 0.5 MPa, the separator being part of the low pressure recovery system.

19. A process according to claim 18 wherein the separator is at a temperature of less than 0° C. and/or where the separator is at a pressure of 0.3 MPa or less.

20. A process according to claim 19 wherein the separator is at a temperature of less than −20° C. and/or where the separator is at a pressure of 0.2 MPa or less.

21. A process according to claim 18 wherein the polymerisation process comprises the steps of:
1) Polymerising a monomer and a comonomer in a polymerisation reactor,
2) Withdrawing an effluent stream comprising solid polymer and a mixture comprising unreacted monomer and unreacted comonomer, and passing the effluent to a high pressure recovery system comprising
a. a high pressure separation step for separating a vapour comprising unreacted monomer and unreacted comonomer from said solids, and
b. a recycle system for recycling at least a portion of the vapour to the polymerisation reactor,

3) Passing the solids from the high pressure recovery system to a low pressure recovery system comprising
a. a low pressure separation step for separating further unreacted monomer and unreacted comonomer from said solids, and
b. a recycle system comprising a vapour/liquid separator for recycling at least a portion of the unreacted monomer and unreacted comonomer,

said separator to which the fresh feed is passed being the “vapour/liquid separator” of step 3(b).

22. A process according to claim 21 wherein the polymerisation reactor has a volume of at least 50 m 3 .

23. A process according to claim 15 wherein the polymerisation reactor has a volume of at least 50 m 3 .

24. A process according to claim 15 wherein the second stream comprises at least 30 wt % of the second component.

Assignees

• Ineos Europe Ag

Inventors

• Marissal Daniel
• Van Breuseghem Philip
• Walworth Brent R

Classifications

• C08F210/16 Primary

  Copolymers of ethene with alpha-alkenes, e.g. EP rubbers · CPC title

• C08F2/14 Primary

  Organic medium · CPC title

• C08F2/001

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

• C08F210/14

  Monomers containing five or more carbon atoms · CPC title

• C08F2500/12

  Melt flow index or melt flow ratio · CPC title