Method of recovering olefins in a solution polymerization process

Patent metadata

Field	Value
Publication number	US-11149096-B2
Application number	US-201816646606-A
Country	US
Kind code	B2
Filing date	Nov 22, 2018
Priority date	Dec 4, 2017
Publication date	Oct 19, 2021
Grant date	Oct 19, 2021

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 vapor phase coexist; (B) withdrawing a vapor 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 bottom stream to a second fractionator; (F) withdrawing a second overhead stream and a second bottom stream from the second fractionator; characterized in that at least a part of the second overhead stream is withdrawn as a purge stream.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 bottom stream to a second fractionator;
(F) withdrawing a second overhead stream and a second bottom stream from the second fractionator;

characterised in that at least a part of the second overhead stream is withdrawn as a purge stream.

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

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

4. The process according to claim 3 comprising the additional step of:
(G) passing optionally at least a part of the second overhead stream to a polymerization reactor.

5. The process according to claim 3 comprising the additional step of:
(H) passing the first overhead stream to a third fractionator;
(I) withdrawing a third overhead stream and a third bottom stream from the third fractionator;
(J) passing the third overhead stream to a fourth fractionator;
(K) withdrawing a fourth overhead stream and a fourth bottom stream from the fourth fractionator;
(L) passing optionally at least a part of the fourth overhead stream to the polymerization reactor.

6. The process according to claim 3 comprising the additional step of:
(M) passing optionally at least a part of the fourth bottom stream to the polymerization reactor.

7. The process according to claim 3 comprising the additional steps of:
(N) passing optionally at least a part of any of the second overhead stream, fourth overhead stream or fourth bottom stream to a feed vessel;
(O) withdrawing a feed stream from the feed vessel;
(P) passing the feed stream via a cooling step to the polymerization reactor.

8. The process according to claim 3 wherein the stream of the solution comprises ethylene.

9. The process according to claim 3 wherein any of the first, second, third or fourth fractionators are distillation columns, stripping columns, multi-phase separators, extractors or liquid-liquid separators.

10. The process according to claim 3 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 3 wherein at least a part of the purge stream is sent to a hydrogenation step.

12. The process according to claim 3 wherein at least a part of the purge stream is sent to an isomerization step.

Assignees

• Borealis Ag

Inventors

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

Classifications

• C08F6/003 Primary

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

• C08F2/06

  Organic solvent · CPC title