Loop reactor providing an advanced production split control

Patent metadata

Field	Value
Publication number	US-9475896-B2
Application number	US-201214365318-A
Country	US
Kind code	B2
Filing date	Dec 12, 2012
Priority date	Dec 19, 2011
Publication date	Oct 25, 2016
Grant date	Oct 25, 2016

Abstract

Method for preparing olefin polymer in a loop reactor, said loop reactor comprises a first outlet for withdrawing polymer slurry from the loop reactor, and a second outlet for withdrawing a polymer slurry from the loop reactor, wherein the first outlet is located such that polymer slurry is withdrawn having a concentration of polymer which is equal or higher than the average concentration of polymer in the loop reactor, and the second outlet is located such that polymer slurry is withdrawn having a concentration of polymer which is lower than the average concentration of polymer in the loop reactor, the method comprises the steps of supplying olefin monomers and a catalytic system to the loop reactor to form a polymer slurry in the loop reactor, and controlling the total amount of polymer and/or the total amount of polymer slurry withdrawn from the loop reactor by adjusting the ratio of polymer slurry withdrawn through the first outlet and polymer slurry withdrawn through the second outlet.

First claim

The invention claimed is:

1. A method for preparing olefin polymer in at least one loop reactor, said loop reactor comprises:
(a) at least one lower horizontal segment and/or at least one lower bend,
(b) at least one upper horizontal segment and/or at least one upper bend, and
(c) at least two vertical segments,
connected in operable communication,
said loop reactor further comprises
(d) a first outlet for withdrawing a first polymer slurry from the loop reactor, said first polymer slurry comprises olefin polymer and fluid phase; said first outlet is located such that the first polymer slurry withdrawn has a concentration of polymer which is the same as or higher than the average concentration of polymer in the loop reactor, and
(e) a second outlet for withdrawing a second polymer slurry from the loop reactor, said second polymer slurry comprises olefin polymer and fluid phase; said second outlet is located such that the second polymer slurry withdrawn has a concentration of polymer which is lower than the average concentration of polymer in the loop reactor,
the method comprises the steps of
(i) supplying olefin monomers, a catalytic system, and optionally olefin comonomers to the loop reactor to form a polymer slurry in the loop reactor, and
(ii) controlling
(ii1) the total amount of polymer withdrawn from the loop reactor, and/or
(ii2) the total amount of polymer slurry withdrawn from the loop reactor, and/or
(ii3) the concentration of polymer within the total polymer slurry withdrawn from the loop reactor
by adjusting the ratio of the first polymer slurry withdrawn through the first outlet and the second polymer slurry withdrawn through the second outlet, and

(iii) optionally transferring the withdrawn total polymer slurry into a second reactor.

2. Method according to claim 1 , wherein:
(a) the first polymer slurry and the second polymer slurry are withdrawn through the first and second outlet, respectively, and are directly transferred, into the second reactor, and/or
(b) the first polymer slurry and the second polymer slurry are combined and subsequently transferred into the second reactor.

3. Method according to claim 1 , wherein in the second reactor, a polymer is produced different than the polymer produced in the loop reactor, and the weight ratio of polymer produced in the loop reactor and the polymer produced in the second reactor is 75:25 to 40:60.

4. Method according to claim 1 , wherein the average concentration of polymer in the polymer slurry within the loop reactor is between 15 wt. % and 55 wt. %, based on the total weight of the polymer slurry in the loop reactor.

5. Method according to claim 1 , wherein in case of controlling between 65 wt. % and 95 wt. %, based on the weight of the withdrawn total polymer slurry, of first polymer slurry is withdrawn through the first outlet and between 5 wt. % and 35 wt. %, based on the total weight of the total withdrawn polymer slurry, of second polymer slurry is withdrawn through the second outlet.

6. Method according to claim 1 , wherein the second polymer slurry withdrawn through the second outlet has an amount of polymer of:
(a) more than 0.1 wt. %, based on the total weight of the withdrawn second polymer slurry through the second outlet, and/or
(b) at most 10 wt. %, based on the total weight of the withdrawn second polymer slurry through the second outlet.

7. Method according to claim 1 , wherein the ratio of first polymer slurry withdrawn through the first outlet and second polymer slurry withdrawn through the second outlet [PS-O1/PS-02] is at least 1.8, wherein:
“PS-O1” is the amount of first polymer slurry withdrawn through the first outlet, and
“PS-O2” is the amount in weight percentage of second polymer slurry, withdrawn through the second outlet.

8. Method according to claim 1 , wherein:
(a) the first polymer slurry is withdrawn intermittently or continuously through the first outlet, and/or
(b) the second polymer slurry is withdrawn intermittently or continuously through second outlet.

9. Method according to claim 1 , wherein the first outlet is located at the outer periphery of the loop reactor and/or the second outlet is located at the inner periphery of the loop reactor.

10. Method according to claim 1 , wherein the loop reactor comprises:
(a) one lower horizontal segment,
(b) two lower bends,
(c) one upper horizontal segment,
(d) two upper bends, and
(e) two vertical segments,
connected in operable communication, wherein the two lower bends joining the lower horizontal segment with the two vertical segments and the two upper bends joining the upper horizontal segment with the two vertical segments,
the first outlet is located at the outer periphery of the lower horizontal segment or of one of the two lower bends of the loop reactor, and
the second outlet is located at
(i) the inner periphery of the lower horizontal segment of the loop reactor or of the inner periphery of one of the two lower bends of the loop reactor, and/or
(ii) the inner periphery of the upper horizontal segment of the loop reactor or the inner periphery of one of the two upper bends of the loop reactor.

11. Method according to claim 1 , wherein the loop reactor comprises
(a) one lower bend,
(b) one upper bend, and
(c) two vertical segments
connected in operable communication, wherein the lower bend and upper bend joining the two vertical segments,
the first outlet is located at the outer periphery of the lower bend of the loop reactor, and
the second outlet is located at
(i) the inner periphery of the lower bend of the loop reactor, and/or
(ii) the inner periphery of the upper bend of the loop reactor.

12. Method according to claim 1 , wherein:
(a) the first and second outlet are connected with the second reactor via separate conduits, and/or
(b) the conduit of the first outlet and the conduit of the second outlet are connected to each other at a connection point upstream to the second reactor and a further conduit leads form said connecting point into the second reactor.

13. Polymerization reactor system comprising a plurality of polymerization reactor vessels for preparing olefin polymers, said polymerization reactor system comprises in a cascade at least one loop reactor and at least one further reactor,
wherein said loop reactor comprises:
(a) at least one lower horizontal segment and/or at least one lower bend,
(b) at least one upper horizontal segment and/or at least one upper bend, and
(c) at least two vertical segments
connected in operable communication,
said loop reactor further comprises a first and second outlet suitable for withdrawing polymer slurry,
said first and second outlet are connected with the second reactor via a conduit,
wherein further,
the first outlet is located at the outer periphery of the lower horizontal segment or of the lower bend of the loop reactor and
the second outlet is located at
(i) the inner periphery of the lower horizontal segment of the loop reactor or of the inner periphery of the lower bend of the loop reactor, and/or
(ii) the inner periphery of the upper horizontal segment of the loop reactor or the inner periphery of the upper bend of the loop reactor.

14. Polymerization reactor system according to claim 13 , wherein the conduit of the first outlet and the conduit of the second outlet are connected to each other at a connection point upstream to the second reactor and a further conduit leads from said connecting point into the second reactor.

15. Method for controlling the average residence time of an olefin polymer formed in a loop reactor

Assignees

• Borealis Ag

Inventors

• Leskinen Pauli
• Hakola Sameli
• Alastalo Kauno
• Nyfors Klaus

Classifications

• B01J19/0053

  Details of the reactor · CPC title

• C08F210/06

  Propene · CPC title

• C08F110/06 Primary

  Propene · CPC title

• B01J19/245

  placed in series · CPC title

• B01J2219/00049

  Controlling or regulating processes · CPC title