Process for recycling solvent used in an ethylene-based polymerization reaction and system therefor

Patent metadata

Field	Value
Publication number	US-9708418-B2
Application number	US-201214001220-A
Country	US
Kind code	B2
Filing date	Feb 16, 2012
Priority date	Mar 8, 2011
Publication date	Jul 18, 2017
Grant date	Jul 18, 2017

Abstract

A process for recycling solvent used in an ethylene-based polymerization comprising: passing a solvent stream which has been used in a first ethylene-based solvent polymerization reactor through an online purification bed to produce a recycle solvent stream, wherein the solvent stream prior to being passed through the online purification bed comprises solvent, ethylene, hydrogen, polymerization by-products and optionally comonomer; and passing the recycle solvent stream from the online purification bed to a second ethylene-based solvent polymerization reactor; wherein the second ethylene-based solvent polymerization reactor exhibits a catalyst efficiency dip of less than or equal to 20% for no longer than a forty-eight hour period following a swap of the online purification bed to a regenerated purification bed which contains an adsorbent having low reactivity to alkenes is provided.

First claim

We claim:

1. A process for recycling solvent used in an ethylene-based polymerization comprising:
providing a first regenerated purification bed comprising an adsorbent which, upon exposure to a chlorooctane and ethylene produces less than or equal to 650 mg ethylene dimer/(kg adsorbent* h);
swapping said regenerated purification bed with a first online purification bed in an ethylene-based solvent polymerization system;
thereby converting said regenerated purification bed into an alternative online purification bed in said ethylene-based solvent polymerization system and converting said online purification bed into an alternative regenerated purification bed;
conveying a solvent stream comprising solvent, ethylene, hydrogen, polymerization by-products and optionally comonomer from a first ethylene-based solvent polymerization reactor to the alternative online purification;
passing said solvent stream comprising solvent, ethylene, hydrogen, polymerization by-products and optionally comonomer through the alternative online purification bed to produce a recycled solvent stream comprising a recycled solvent; and
passing the recycled solvent stream from the alternative online purification bed to a second ethylene-based solvent polymerization reactor;
wherein the second ethylene-based solvent polymerization reactor polymerizes ethylene and optionally one or more α-olefins in the presence of said recycled solvent and exhibits a catalyst efficiency dip of less than or equal to 20% for no longer than a forty-eight hour period following said swap.

2. The process according to claim 1 , wherein the first and second ethylene-based solvent polymerization reactors are the same reactor.

3. The process according to claim 1 , wherein the first and second ethylene-based solvent polymerization reactors are different reactors.

4. The process according to claim 1 , wherein the adsorbent is a hybrid zeolite/modified alumina adsorbent.

5. The process according to claim 4 , wherein the adsorbent is an alumina-zeolite composite comprising an alkali metal aluminosilicate having the general formula Na x [(AlO 2 ) x (SiO 2 ) y ].zH 2 O hybrid with alumina.

6. The process according to claim 1 , wherein the catalyst efficiency dip is 12% or less.

7. The process according to claim 1 , wherein the catalyst efficiency dip is 6% or less.

8. The process according to claim 1 , wherein the catalyst efficiency dip is 2% or less.

9. The process according to claim 1 , wherein at least one of the first and second ethylene-based solvent polymerization reactors contains a coordination catalyst.

10. The process according to claim 1 , wherein at least one of the first and second ethylene-based solvent polymerization reactors contains a Ziegler-Natta catalyst.

11. The process according to claim 1 , wherein at least one of the first and second ethylene-based solvent polymerization reactors contains a molecular catalyst.

12. The process according to claim 1 , wherein the recycle solvent further comprises a component selected from the group consisting of calcium stearate, reaction by-products of calcium stearate, and combinations thereof.

13. The process according to claim 1 , wherein the recycle solvent further comprises a component selected from the group consisting of a natural hydrotalcite, a synthetic hydrotalcite-type material, reaction by-products of the natural or synthetic hydrotalcite-type material, and combinations thereof.

Assignees

• Hyde Stacey
• Castelluccio Anthony J
• Gemoets Frederik E
• Dow Global Technologies Llc

Inventors

• Hyde Stacey
• Castelluccio Anthony J
• Gemoets Frederik E

Classifications

• C08F210/14

  Monomers containing five or more carbon atoms · CPC title

• B01D15/00 Primary

  Separating processes involving the treatment of liquids with solid sorbents; Apparatus therefor · CPC title

• B01J2219/00038

  Processes in parallel · CPC title

• C08F210/02

  Ethene · CPC title

• C08L23/04

  Homopolymers or copolymers of ethene · CPC title