Multistage process for the polymerization of olefins

Patent metadata

Field	Value
Publication number	US-2016108147-A1
Application number	US-201414889794-A
Country	US
Kind code	A1
Filing date	May 13, 2014
Priority date	May 16, 2013
Publication date	Apr 21, 2016
Grant date	—

Abstract

A process for polymerizing olefins in at least two serially connected gas-phase polymerization reactors, the process for transferring polyolefin particles from a first gas-phase polymerization reactor to a second gas-phase polymerization reactor comprising the steps of:
a) discharging polyolefin particles into a separation chamber being at a lower pressure than the pressure in the first reactor; b) transferring the polyolefin particles within the separation chamber into a lower part which contains a bed of polyolefin particles which moves from top to bottom of this part of the separation chamber and into which a fluid is introduced so that an upward fluid stream is induced, c) withdrawing polyolefin particles from the lower end and transferring them to one of at least two lock hoppers working intermittently in parallel; and d) simultaneously pressurizing another of the at least two lock hoppers working intermittently by means of a gas comprising reaction gas coming from the second reactor.

First claim

1 . A process for polymerizing olefins at temperatures of from 30° C. to 140° C. and pressures of from 1.0 MPa to 10 MPa in the presence of a polymerization catalyst in a multistage polymerization of olefins in at least two serially connected gasphase polymerization reactors, the process for transferring polyolefin particles from a first gas-phase polymerization reactor to a second gas-phase polymerization reactor comprising the steps of:
a) discharging polyolefin particles from the first gas-phase polymerization reactor into a separation chamber wherein the polyolefin particles are separated from concomitantly discharged reaction gas, the separation chamber being at a lower pressure than the pressure in the first gas-phase polymerization reactor;
b) transferring the polyolefin particles within the separation chamber into a lower part of the separation chamber comprising a bed of polyolefin particles which moves from top to bottom of this part of the separation chamber and into which a fluid is introduced in an amount capable of producing an upward stream of the fluid in the bed of polyolefin particles above the fluid introduction point;
c) withdrawing polyolefin particles from the lower end of the lower part of the separation chamber and transferring the polyolefin particles to at least one lock hopper operating intermittently in parallel; and
d) simultaneously pressurizing one or more lock hoppers that do not comprise the polyolefin particles and operating intermittently by means of a gas comprising reaction gas coming from the second gas-phase polymerization reactor.

2 . The process off claim 1 , wherein the bed of polyolefin particles moves as plug flow from the top portion to the bottom portion of the lower part of the separation chamber.

3 . The process off claim 1 , wherein the lower part of the separation chamber comprising, the bed of polyolefin particles comprises a conduit of a diameter smaller than the diameter of an upper part of the separation chamber.

4 . The process off claim 3 , wherein the conduit is arranged substantially vertically.

5 . The process off claim 3 , wherein the lower end of the conduit tapers conically.

6 . The process off claim 1 , wherein the multistage polymerization of olefins is a multistage polymerization selected from ethylene and ethylene and comonomer, wherein the polymerization in the first polymerization reactor is carried out in the presence of hydrogen.

7 . The process off claim 1 , wherein the fluid introduced into the conduit is an inert gas.

8 . The process off claim 1 , wherein the pressure in the separation chamber is in a range of from 0.12 to 0.4 MPa.

9 . A process for polymerizing olefins according to claim 1 , wherein one or more of the lock hoppers are optionally:
loaded with polyolefin particles coming from the lower part of the separation chamber while the lock hopper is isolated from the second gas-phase polymerization reactor; pressurized using reaction gas from the second gas-phase polymerization reactor; dischard of the polyolefin particles via transfer to the second gas-phase polymerization reactor while the lock hopper is isolated from the separation chamber.

10 . An apparatus for performing the process of claim 1 , comprising at least two serially connected gas-phase polymerization reactors and a device for transferring polyolefin particles from an upstream gas-phase polymerization reactor to a downstream gas-phase polymerization reactor, the transferring device comprising:
a gas/solid separation chamber arranged downstream of the upstream gas-phase polymerization reactor, wherein the gas/solid separation chamber comprises a lower part comprising an inlet for introducing a fluid; and at least two lock hoppers operably connected to the gas/solid separation chamber, wherein the at least two lock hoppers are in a parallel arrangement and operably connected to the downstream gas-phase polymerization reactor.

11 . The apparatus off claim 10 , wherein the lower part comprising an inlet comprises a conduit of a diameter smaller than the diameter of an upper part of the gas/solid separation chamber.

12 . The apparatus off claim 10 , wherein the conduit is arranged substantially vertically.

13 . The apparatus off claim 10 , wherein the lower end of the conduit tapers conically.

14 . The apparatus off claim 10 , wherein each of the at least two lock hoppers is connected to the lower part of the gas/separation chamber through a separate discharge valve.

15 . The apparatus off claim 10 , wherein each of the at least two lock hoppers is connected to the second gas-phase polymerization reactor via a separated transfer pipe, each transfer pipe comprising a discharge valve.

16 . The apparatus of claim 11 , wherein the fluid introduced into the conduit is an inert gas.

17 . The apparatus of claim 16 , wherein the inert gas comprises one or more of ethane, propane, butane, pentane, hexane and nitrogen.

Assignees

• Basell Polyolefine Gmbh

Inventors

• Penzo Giuseppe
• Mei Gabriele
• Meier Gerhardus
• Schueller Ulf
• Ciarrocchi Antonio

Classifications

• C08F110/02 Primary

  Ethene · CPC title

• B01J2208/00761

  Discharging · CPC title

• B01J8/0025

  by an ascending fluid · CPC title

• B01J2208/00292

  involving reactant solids · CPC title

• B01J8/26

  with two or more fluidised beds, e.g. reactor and regeneration installations · CPC title