High pressure, free radical polymerizations to produce ethylene-based polymers

Patent metadata

Field	Value
Publication number	US-11078301-B2
Application number	US-201716302806-A
Country	US
Kind code	B2
Filing date	Jun 22, 2017
Priority date	Jun 25, 2015
Publication date	Aug 3, 2021
Grant date	Aug 3, 2021

Abstract

A high pressure polymerization, as described herein, to form an ethylene-based polymer, comprising the following steps: polymerizing a reaction mixture comprising ethylene, using a reactor system comprising at least three ethylene-based feed streams and a reactor configuration that comprises at least four reaction zones, and at least one of the following a) through c), is met: (a) up to 100 wt % of the ethylene stream to the first zone comes from a high pressure recycle, and/or up to 100 wt % of the last ethylene stream to a zone comes from the output from a Primary compressor system; and/or (b) up to 100 wt % of the ethylene stream to first zone comes from the output from a Primary compressor system, and/or up to 100 wt % of the last ethylene stream to a zone comes from a high pressure recycle; and/or (c) the ethylene stream to the first zone, and/or the last ethylene stream to a zone, each comprises a controlled composition; and wherein each ethylene stream to a zone receives an output from two or more cylinders of the last compressor stage of a Hyper compressor system.

First claim

The invention claimed is:

1. A high pressure polymerization process to form an ethylene-based polymer, the process comprising at least the following steps:
polymerizing a reaction mixture comprising ethylene, using a reactor system comprising at least three ethylene-based feed streams and a reactor configuration that comprises at least four reaction zones, and
wherein at least one of the following distributions a) through c), is met:
(a) up to 100 wt % of the ethylene-based feed stream to a first reaction zone of the four reaction zones comes from a high pressure recycle, and/or up to 100 wt % of a last ethylene-based feed stream to a reaction zone comes from an output from a Primary compressor system; and/or
(b) up to 100 wt % of the ethylene-based feed stream to the first reaction zone comes from the output from a Primary compressor system, and/or up to 100 wt % of the last ethylene-based feed stream to a reaction zone comes from the high pressure recycle; and/or
(c) the ethylene-based feed stream to the first reaction zone, and/or the last ethylene-based feed stream to a reaction zone, each comprises a controlled composition;
and wherein each ethylene-based feed stream to a reaction zone, independently, receives an output from two or more cylinders of a last compressor stage of a Hyper compressor system;
and wherein the ethylene-based feed stream to the first reaction zone is from 20 wt % to 60 wt % of the total ethylene-based feed stream to the reactor configuration; and
wherein the sum of the last two ethylene-based feed streams to the reactor configuration is from 20 wt % to 80 wt % of the total ethylene-based feed streams to the reactor configuration.

2. The process of claim 1 , wherein the weight percent of ethylene-based feed flow, from the output of the Primary compressor system, and in the feed to the first reaction zone is varied using the smaller of range i) or range ii) as follows:
i) the ethylene-based feed flow from the output of the Primary compressor system is from 0 wt % to 100 wt %;
ii) the ethylene-based feed flow from the output of the Primary compressor system is from 0 wt %, to a value determined by the following equation:

[

(

Conversion
×
1.25

)

+
purge

]

X

×
100
⁢

⁢
wt
⁢

⁢
%

,

wherein X is the percentage of the ethylene-based feed stream to the first reaction zone, based on the total amount of ethylene-based streams to the reactor configuration, and the “conversion (in wt %)” is the “polymer output divided by the total feed flow to the reactor configuration,” and the purge from the high pressure recycle is in wt %.

3. The process of claim 1 , wherein the weight percent of ethylene-based feed flow, from the output of the Primary compressor system, and in the feed to the last two reaction zone, receiving an ethylene-based feed stream, is varied using the smaller range i) or ii) as follows:
i) the ethylene-based feed flow from the output of the Primary compressor system is from 0 wt % to 100 wt %;
ii) the ethylene-based feed flow from the output of the Primary compressor system is from 0 wt % to a value defined by the following equation:

[

(

Conversion
×
1.25

)

+
purge

]

Y

×
100
⁢
%
⁢

⁢
wt

,

wherein Y is the percentage of the ethylene-based feed stream to the last two reaction zones, receiving an ethylene-based feed, based on the total amount of ethylene-based streams to the reactor configuration, and the “conversion (in wt %)” is the “polymer output divided by the total feed flow to the reactor configuration,” and the purge from the high pressure recycle is in wt %.

4. The process of claim 1 , wherein the weight percent of ethylene-based feed flow, from the output of the Primary compressor system, and in the feed to the last reaction zone, receiving an ethylene-based feed stream, is varied using the smaller range i) or ii) as follows:
i) from 0 wt % to 100 wt %, or
ii) from 0 wt % to a value determined by the following equation:

Conversion
×
1.25

+

wt
⁢

⁢
%
⁢

⁢
purge

W

×
100
⁢
%
⁢

⁢
wt

,

wherein W is the percentage of the ethylene-based feed stream to the last reaction zone, receiving an ethylene-based feed, based on the total amount of ethylene-based streams to the reactor configuration, and the “conversion (in wt %)” is the “polymer output divided by the total feed flow to the reactor configuration,” and the purge from the high pressure recycle is in wt %.

5. The process of claim 1 , wherein the compositions of the ethylene-based feed streams going to the first and last reaction zones, each receiving an ethylene-based feed, are each controlled with a control system comprising a valve system, through which an ethylene-based feed stream is flowed, to be later compressed and/or delivered to the respective reaction zone.

6. The process of claim 1 , wherein the reactor system further comprises at least one analyzer for detecting a component of a stream of the reactor configuration or determining a property of the ethylene-based polymer produced by the high pressure polymerization process.

7. The process of claim 1 , wherein the reactor configuration comprises at least one tubular reactor.

8. The process of claim 2 , wherein the weight percent of ethylene-based feed flow, from the output of the P

Assignees

• Dow Global Technologies Llc

Inventors

• Hosman Cornelis J F
• Dang Nhi T Y
• Berbee Otto J
• Flores Joaquin

Classifications

• Y02P20/582

  Recycling of unreacted starting or intermediate materials · CPC title

• C08F2/01

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

• B01J3/046

  Pressure-balanced vessels · CPC title

• C08F6/001

  Removal of residual monomers by physical means · CPC title

• B01J2203/06

  High pressure synthesis · CPC title