Method of recovering olefins in a solution polymerisation process

Patent metadata

Field	Value
Publication number	US-11512157-B2
Application number	US-201816768601-A
Country	US
Kind code	B2
Filing date	Nov 22, 2018
Priority date	Dec 4, 2017
Publication date	Nov 29, 2022
Grant date	Nov 29, 2022

Abstract

The present invention relates to a process for removing hydrocarbons comprising the steps of:(A) passing a stream of a solution into a separator wherein a liquid phase comprising polymer and a vapour phase coexist;(B) withdrawing a vapour stream and a concentrated solution stream from the separator;(C) passing at least a part of the vapour stream into a first fractionator;(D) withdrawing a first overhead stream and a first bottom stream from the first fractionator;(E) passing the first overhead stream to a second fractionator;(F) withdrawing a second overhead stream and a second bottom stream from the second fractionator;(G) passing the second overhead stream to a third fractionator;(H) withdrawing a third overhead stream and a third bottom stream from the third fractionator;characterised in that at least a part of the third bottom stream is withdrawn as a purge stream.

First claim

The invention claimed is:

1. A process for removing hydrocarbons comprising the steps of:
(A) passing a stream of a solution into a separator wherein a liquid phase comprising polymer and a vapour phase coexist;
(B) withdrawing a vapour stream and a concentrated solution stream from the separator;
(C) passing at least a part of the vapour stream into a first fractionator;
(D) withdrawing a first overhead stream and a first bottom stream from the first fractionator;
(E) passing the first overhead stream to a second fractionator;
(F) withdrawing a second overhead stream and a second bottom stream from the second fractionator;
(G) passing the second overhead stream to a third fractionator;
(H) withdrawing a third overhead stream and a third bottom stream from the third fractionator;
wherein at least a part of the third bottom stream is withdrawn as a purge stream.

2. The process according to claim 1 wherein the stream of the solution comprises 1-hexene and n-octane and a mixture of isomers of 1-hexene and n-hexane.

3. The process according to claim 2 comprising the step of purging isomers of 1-hexene and n-hexane with the purge stream.

4. The process according to claim 1 , comprising the additional step of:
(I) passing the first bottom stream to a fourth fractionator;
(J) withdrawing a fourth overhead stream and a fourth bottom stream from the fourth fractionator;
(K) passing optionally at least a part of the fourth overhead stream to a polymerisation reactor.

5. The process according to claim 1 , comprising the additional step of:
(L) passing at least a part of the third overhead stream to a polymerisation reactor.

6. The process according to claim 1 , comprising the additional step of:
(M) passing at least a part of the third bottom stream to a polymerisation reactor.

7. The process according to claim 1 , comprising the additional steps of:
(N) passing at least a part of any of the third bottom stream, or third overhead stream to a feed vessel;
(O) withdrawing a feed stream from the feed vessel;
(P) passing the feed stream via a cooling step to a polymerisation reactor.

8. The process according to claim 1 , wherein the stream of the solution comprises ethylene.

9. The process according to claim 1 , wherein any of the first, second, or third fractionators are distillation columns, stripping columns, multi-phase separators, extractors, or liquid-liquid separators.

10. The process according to claim 1 , wherein at least a part of the purge stream is used as a gasoline additive or as a fuel additive.

11. The process according to claim 1 , wherein at least a part of the purge stream sent to a hydrogenation step.

12. The process according to claim 1 , wherein at least a part of the purge stream is sent to an isomerisation step.

13. The process according to claim 4 , comprising the additional steps of:
(N) passing at least a part of any of the fourth overhead stream to a feed vessel;
(O) withdrawing a feed stream from the feed vessel;
(P) passing the feed stream via a cooling step to a polymerisation reactor.

14. The process according to claim 4 , wherein the fourth fractionator is a distillation column, stripping column, multi-phase separator, extractor, or liquid-liquid separator.

Assignees

• Borealis Ag

Inventors

• Al-Haj Ali Mohammad
• Eriksson Erik
• Mathivanan Guhan
• Räsänen Jukka
• Sleijster Henry
• Vijay Sameer
• Zitting Samuli

Classifications

• C08F210/16 Primary

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

• C08F2/06

  Organic solvent · CPC title

• C08F2/01

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

• C08F10/02

  Ethene · CPC title

• C08F6/005

  from solid polymers · CPC title