Process for withdrawing polyolefins

Patent metadata

Field	Value
Publication number	US-10604595-B2
Application number	US-201615776089-A
Country	US
Kind code	B2
Filing date	Dec 21, 2016
Priority date	Dec 21, 2015
Publication date	Mar 31, 2020
Grant date	Mar 31, 2020

Abstract

A process for withdrawing polyolefins from a reactor includes: continuously withdrawing a liquid solution stream from a solution polymerization reactor and passing the liquid solution stream into a low pressure separator; withdrawing a first vapour stream and a first liquid stream from the separator and passing the first vapour stream into a washing column; withdrawing a second vapour stream from the washing column and feeding it via a condenser line to a condenser; cooling the second vapour stream in the condenser so that part of the second vapour stream condenses, producing a condensed second vapour stream and an uncondensed second vapour stream; passing the condensed second vapour stream to an upper part of the washing column via a reflux line; withdrawing a second liquid stream from the washing column and passing at least part of the second liquid stream to the separator via a recycling line; and recovering heat.

First claim

The invention claimed is:

1. A process for withdrawing polyolefins from a solution polymerization reactor comprising:
(a) providing
a low pressure separator 1 ,
a washing column 2 ,
a withdrawal line 3 connecting the upper part of the low pressure separator and the washing column
a condenser 4 ,
a condenser-line 5 connecting the top part of the washing column and the condenser
optionally a recycle solvent vessel 6
optionally a solvent-vessel-line 7 connecting the condenser with the recycle solvent vessel
a reflux line 8 connecting the condenser and the upper part of the washing column or connecting the recycle solvent vessel and the upper part of the washing column
optionally a circulation line 9 fluidly connected to the middle part of the washing column and recycling line 10
a recycling line 10 connecting the bottom of the washing column and the upper part of the low pressure separator,
optionally a wash recycle heater 11 embedded into the recycling line 10
optionally a heater 12 embedded into the circulation line 9

(b) continuously withdrawing a liquid solution stream from the solution polymerization reactor and passing said liquid solution stream into the first low pressure separator 1 ;
(c) withdrawing a first vapour stream and a first liquid stream from the low pressure separator and passing said first vapour stream via withdrawal line 3 into the washing column
(d) withdrawing a second vapour stream from the washing column and feeding it via condenser line 5 to condenser 4
(e) cooling the second vapour stream in condenser 4 so that a part of the second vapour stream condenses thereby producing a condensed second vapour stream and an uncondensed second vapour stream
(f) passing the condensed second vapour stream to the upper part of the washing column via reflux line 8
(g) withdrawing a second liquid stream from the washing column and passing at least a part of the second liquid stream to the low pressure separator via recycling line 10
(h) recovering heat from the condenser.

2. The process of claim 1 , whereby the whole second liquid stream is passed to the low pressure separator.

3. The process of claim 1 , whereby a part of the second liquid stream is passed to the low pressure separator and the remaining part of the second liquid stream is passed to the washing column via circulation line 9 .

4. The process of claim 3 , whereby the remaining part of the second liquid stream which is passed to the washing column is at least partially heated by heater 12 .

5. The process according to claim 1 , whereby the second liquid stream passed to the low pressure separator is heated by wash recycle heater 11 .

6. A process for double stage withdrawing polyolefins from a solution polymerization reactor comprising:
(a) providing
a first low pressure separator 1 ,
a first washing column 2 ,
a first withdrawal line 3 connecting the upper part of the first low pressure separator and the first washing column
a first condenser 4 ,
a first condenser-line 5 connecting the top part of the first washing column and the first condenser
optionally a first recycle solvent vessel 6
optionally a first solvent-vessel-line 7 connecting the first condenser with the first recycle solvent vessel
a first reflux line 8 connecting the first condenser and the upper part of the first washing column or connecting the first recycle solvent vessel and the upper part of the first washing column
optionally a first circulation line 9 fluidly connected to recycling line 10 and the middle part of the washing column
a first recycling line 10 connecting the bottom of the washing column and the upper part of the first low pressure separator,
optionally a first wash recycle heater 11 embedded into the recycling line 10
optionally a first heater 12 embedded into the circulation line 9
further providing
a second low pressure separator 15 ,
a second washing column 16 ,
a second withdrawal line 17 connecting the upper part of the second low pressure separator and the second washing column
a second condenser 18 ,
a second condenser-line 19 connecting the upper part of the second washing column and the second condenser
optionally a second recycle solvent vessel 20
optionally a second solvent-vessel-line 21 connecting the second condenser with the second recycle solvent vessel
a second reflux line 22 connecting the second condenser and the upper part of the second washing column or connecting the second recycle solvent vessel and the upper part of the second washing column
optionally a second circulation line 23 fluidly connected to connecting line 24 and the middle part of the second washing column
a connecting line 24 connecting the bottom of the second washing column and the first recycling line 10 or low pressure separator 1
optionally a second heater 25 embedded into the second circulation line 23

(b) continuously withdrawing a liquid solution stream from the solution polymerization reactor and passing said liquid solution stream into the first low pressure separator 1 ; further passing a second liquid solution stream into the second low pressure separator 15 ;
(c) withdrawing a first vapour stream A and a first liquid stream A from the first low pressure separator 1 and passing said first vapour stream A via the first withdrawal line 3 into the first washing column 2 ; further withdrawing a first vapour stream B and a first liquid stream B from the second low pressure separator 15 and passing said first vapour stream B via the second withdrawal line 17 into the second washing column 16
(d) withdrawing a second vapour stream C from the first washing column 2 and feeding it via the first condenser line 5 to the first condenser 4 ; further withdrawing a second vapour stream D from the second washing column 16 and feeding it via the second condenser line 19 to the second condenser 18
(e) cooling the second vapour stream C so that a part of the second vapour stream C condenses thereby producing a condensed second vapour stream C and an uncondensed second vapour stream C; further cooling the second vapour stream D so that a part of the second vapour stream D condenses thereby producing a condensed second vapour stream D and an uncondensed second vapour stream D;
(f) passing the condensed vapour stream C to the upper part of the first washing column 2 via reflux line 8 ; further passing the condensed vapour stream D to the upper part of the second washing column 16 via reflux line 22
(g) withdrawing a second liquid stream E from the first washing column 2 and passing at least a part of said second liquid stream E to the first low pressure separator via recycling line 10 ;
(h) withdrawing a second liquid stream F from the second washing column 16 and feeding said second liquid stream F at least partially back to the first low pressure separator 1 via connecting line 24 .

7. The process of claim 6 , whereby the whole second liquid stream E is passed to the first low pressure separator.

8. The process of claim 6 , whereby a part of the second liquid stream E is passed to the first low pressure separator and the remaining part of the second liquid stream E is passed to the first washing column via circulation line 9 .

9. The process of claim 8 , whereby the remaining part of the second liquid stream E which is passed to the washing column is at least partially heated by heater 12 .

10. The process according to claim 6 , whereby the second liquid stream E passed to the first low pressure separator is heated by wash recycle heater 11 .

Assignees

• Borealis Ag

Inventors

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

Classifications

• C08F6/003 Primary

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

• B01J8/0015

  Feeding of the particles in the reactor; Evacuation of the particles out of the reactor · CPC title

• C08L23/02

  not modified by chemical after-treatment · CPC title

• C08F6/12 Primary

  Separation of polymers from solutions · CPC title

• C08F2/01

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