Method of recovering olefins in a solution polymerization process

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characterised in that at least a part of the second overhead stream is withdrawn as a purge stream.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