Multiple reactor and multiple zone polyolefin polymerization

Patent metadata

Field	Value
Publication number	US-10858458-B2
Application number	US-201916538412-A
Country	US
Kind code	B2
Filing date	Aug 12, 2019
Priority date	Dec 27, 2018
Publication date	Dec 8, 2020
Grant date	Dec 8, 2020

Abstract

Apparatuses and processes that produce multimodal polyolefins, and in particular, polyethylene resins, are disclosed herein. This is accomplished by using two reactors in series, where one of the reactors is a multi-zone circulating reactor that can circulate polyolefin particles through two polymerization zones optionally having two different flow regimes so that the final multimodal polyolefin has improved product properties and improved product homogeneity.

First claim

What is claimed is:

1. A process for producing a multimodal polyolefin, the process comprising:
polymerizing ethylene in a first reactor to produce a first polyolefin;
receiving the first polyolefin from the first reactor into a second reactor comprising a riser, an upper conduit, a separator, a downcomer, a lower conduit, and optionally a liquid barrier;
polymerizing ethylene in a first reaction mixture containing the first polyolefin in the riser of the second reactor to produce a second polyolefin;
passing the first reaction mixture through the upper conduit from the riser to the separator;
recovering, in the separator, the first polyolefin and the second polyolefin from the first reaction mixture;
passing the first polyolefin and the second polyolefin from the separator into the downcomer, optionally via the liquid barrier;
polymerizing ethylene in a second reaction mixture containing the first polyolefin and the second polyolefin in the downcomer to produce the multimodal polyolefin comprising the first polyolefin, the second polyolefin, and a third polyolefin;
passing a first portion of the second reaction mixture through the lower conduit from the downcomer to the riser; and
discharging, through a take-off valve, a second portion of the second reaction mixture from the downcomer,
wherein the second reaction mixture comprises greater than 50 wt. % of solid polyolefin particles based on a total weight of the second reaction mixture.

2. A process for producing a multimodal polyolefin, the process comprising:
polymerizing ethylene in a first reactor to produce a first polyolefin;
receiving the first polyolefin from the first reactor into a second reactor comprising a riser, an upper conduit, a separator, a downcomer, a lower conduit, and optionally a liquid barrier;
polymerizing ethylene in a first reaction mixture containing the first polyolefin in the riser of the second reactor to produce a second polyolefin;
passing the first reaction mixture through the upper conduit from the riser to the separator;
recovering, in the separator, the first polyolefin and the second polyolefin from the first reaction mixture;
passing the first polyolefin and the second polyolefin from the separator into the downcomer, optionally via the liquid barrier;
polymerizing ethylene in a second reaction mixture containing the first polyolefin and the second polyolefin in the downcomer to produce the multimodal polyolefin comprising the first polyolefin, the second polyolefin, and a third polyolefin;
passing a first portion of the second reaction mixture through the lower conduit from the downcomer to the riser;
discharging, through a take-off valve, a second portion of the second reaction mixture from the downcomer; and
creating fast fluidization conditions in the riser by providing i) an eductor having a suction inlet fluidly connected to the downcomer or to the lower conduit or ii) a standpipe fluidly connected to the lower conduit or to the riser.

3. A process for producing a multimodal polyolefin, the process comprising:
polymerizing ethylene in a first reactor to produce a first polyolefin;
receiving the first polyolefin from the first reactor into a second reactor comprising a riser, an upper conduit, a separator, a downcomer, a lower conduit, and optionally a liquid barrier;
polymerizing ethylene in a first reaction mixture containing the first polyolefin in the riser of the second reactor to produce a second polyolefin;
passing the first reaction mixture through the upper conduit from the riser to the separator;
recovering, in the separator, the first polyolefin and the second polyolefin from the first reaction mixture;
passing the first polyolefin and the second polyolefin from the separator into the downcomer, optionally via the liquid barrier;
polymerizing ethylene in a second reaction mixture containing the first polyolefin and the second polyolefin in the downcomer to produce the multimodal polyolefin comprising the first polyolefin, the second polyolefin, and a third polyolefin;
passing a first portion of the second reaction mixture through the lower conduit from the downcomer to the riser; and
discharging, through a take-off valve, a second portion of the second reaction mixture from the downcomer,
wherein the first reactor is a fluidized bed reactor,
wherein receiving the first polyolefin from the first reactor into the second reactor the process comprises:
receiving the first polyolefin and a gas mixture from a settling leg, a lock hopper, or a continuous take-off valve that is coupled to the first reactor into a separation vessel; and
separating, by the separation vessel, the first polyolefin from the gas mixture,

wherein receiving the first polyolefin from the first reactor into the second reactor the process further comprises:
analyzing a sample of the first polyolefin obtained via a sample take-off conduit fluidly connected to the settling leg, the lock hopper, or the continuous take-off valve.

4. The process of claim 1 , 2 , or 3 , wherein the first polyolefin is a low molecular weight (LMW) component of the multimodal polyolefin, the second polyolefin is an intermediate molecular weight (IMW) component of the multimodal polyolefin, and the third polyolefin is a high molecular weight component (HMW) of the multimodal polyolefin.

5. The process of claim 4 , further comprising:
circulating the multimodal polyolefin in the second reactor from 1 to about 250 cycles before discharging the second portion of the second reaction mixture from the downcomer.

6. The process of claim 4 , wherein a residence time of the second reaction mixture during a single pass through the downcomer is in a range of from about 5 seconds to about 15 minutes.

7. The process of claim 6 , wherein a residence time of the first reaction mixture during a single pass through the riser is in a range of from about 1 second to about 5 minutes.

8. The process of claim 4 , wherein recovering, in the separator, the first polyolefin and the second polyolefin from the first reaction mixture comprises:
separating, by the separator, 99 wt. % or more of solid particles in the first reaction mixture from gas in the first reaction mixture.

9. The process of claim 8 , wherein the separator is a cyclone separator.

10. The process of claim 9 , wherein the cyclone separator is a high efficiency cyclone separator, wherein the 99 wt. % or more of the solid particles that are separated have a particle size of greater than about 10 μm.

11. The process of claim 4 , further comprising:
adding a reactor deactivation agent to the second reactor, wherein the reactor deactivation agent is configured to moderate or kill polymerization reactions in the riser, the downcomer, or both the riser and the downcomer.

12. The process of claim 11 , wherein the reactor deactivation agent is not water.

13. The process of claim 4 , further comprising:
injecting comonomer into the downcomer, wherein the third polyolefin is a copolymer.

14. The process of claim 4 , further comprising:
analyzing a sample of the first reaction mixture at one or more locations in the second reactor to determine a concentration of gas, liquid, or solid in the first reaction mixture, and to determine a concentration of monomer, comonomer, diluent, hydrogen, inert component, or polymer in the first reaction mixture.

15. The process of claim 14 , further comprising:
analyzing a sample of the second reaction mixture at one or more locations in the second reactor to determine a concentration of gas, liquid, or solid in the second reaction mixture, and to de

Assignees

• Chevron Phillips Chemical Co Lp

Inventors

• Curren Joseph A
• Gonzales Rebecca A
• Kufeld Scott E
• Mutchler Joel A
• Netemeyer Eric J
• Sutherland Jamie N
• Deslauriers Paul J
• Fodor Jeffrey S

Classifications

• C08F10/02 Primary

  Ethene · CPC title

• C08L23/0815

  with aliphatic 1-olefins containing one carbon-to-carbon double bond · CPC title

• Y02P20/582

  Recycling of unreacted starting or intermediate materials · CPC title

• B01J2219/00164

  controlling the flow · CPC title

• B01J19/245

  placed in series · CPC title