High-pressure polymerization process of ethylenically unsaturated monomers in a tubular reactor

Patent metadata

Field	Value
Publication number	US-9758603-B2
Application number	US-201715461064-A
Country	US
Kind code	B2
Filing date	Mar 16, 2017
Priority date	Jul 23, 2015
Publication date	Sep 12, 2017
Grant date	Sep 12, 2017

Abstract

The present technology relates to a process for polymerizing or copolymerizing ethylenically unsaturated monomers in the presence of free-radical polymerization initiators, wherein the polymerization is carried out in a continuously operated tubular reactor at temperatures from 100° C. to 350° C. and pressures from 180 MPa to 340 MPa, with a specific reactor surface area A sp of 2 m 2 /(t/h) to 5.5 m 2 /(t/h), and the tubular reactor has a specific ratio RD sp of 0.0050 MPa −1 to 0.0069 MPa −1 and an inner surface which has a surface roughness Ra of 2 μm or less.

First claim

What is claimed is:

1. A tubular reactor for polymerizing or copolymerizing ethylenically unsaturated monomers, comprising:
a length ranging from 0.5-5 km, an inner diameter d i ranging from 50-120 mm, and a length-to-diameter ratio ranging from 1000-50000;
a specific reactor surface area A sp ranging from 2-5.5 m 2 /(t/h), the specific reactor surface area A sp being a ratio of an area of the inner surface of the tubular reactor to a feed rate of reaction gas composition to the tubular reactor ranging from 100-210 t/h; and
an inlet and at least two spatially separated initiator injection points downstream of the inlet.

2. The tubular reactor of claim 1 , wherein the specific reactor surface area A sp ranges from 3-5 m 2 /(t/h).

3. The tubular reactor of claim 1 , wherein the specific reactor surface area A sp ranges from 3.5-4.5 m 2 /(t/h).

4. The tubular reactor of claim 1 , wherein the feed rate for calculating the specific reactor surface area A sp is the combination of feed rates of reaction gas fed to the inlet and the at least two spatially separated initiator injection points.

5. The tubular reactor of claim 1 , further comprising a pipe having a specific ratio RD sp of 0.0050-0.0069 MPa −1 , where RD sp is the ratio of the outer diameter d o to the inner diameter d i divided by a design pressure p des according to the equation:

RD
sp

=

d
o

d
i

*

p
des

.

6. The tubular reactor of claim 5 , wherein the design pressure p des of the tubular reactor ranges from 240-400 MPa.

7. The tubular reactor of claim 5 , wherein the pipe has a ratio of an outer diameter d o to the inner diameter d i ranging from 1.2-2.76.

8. The tubular reactor of claim 7 , wherein the pipe has an inner surface which has a surface roughness Ra of 2 μm or less, determined according to DIN EN ISO 4287:2010.

9. The tubular reactor of claim 1 , wherein the feed rate of the reaction gas composition to the tubular reactor ranges from 120-160 t/h.

10. The tubular reactor of claim 1 , comprising a specific reactor surface area A sp ranging from 2-5.5 m 2 /(t/h), the specific reactor surface area A sp being a ratio of an area of the inner surface of the tubular reactor to a feed rate of reaction gas composition to the tubular reactor ranging from 100-180 t/h.

11. The tubular reactor of claim 5 , wherein the pipe has a tensile strength R m of at least 1100 N/mm 2 as determined according to EN ISO 6892-1:2009.

12. The tubular reactor of claim 5 , wherein an outer diameter d o is essentially constant over the length of the pipe and the inner diameter d i of the pipe is essentially constant over the length of the pipe.

13. The tubular reactor of claim 5 , wherein an outer diameter d o of the pipe, the inner diameter d i of the pipe, or both of the outer diameter d o and the inner diameter d i varies over the length of the pipe.

14. A process for polymerizing or copolymerizing ethylenically unsaturated monomers, comprising:
feeding a reaction gas into a tubular reactor having a specific reactor surface area A sp of 2-5.5 m 2 /(t/h), the specific reactor surface area A sp being a ratio of an area of the inner surface of the tubular reactor to a feed rate of reaction gas composition to the tubular reactor, wherein the tubular reactor has a specific ratio RD sp ranging from 0.0050-0.0069 MPa −1 , where RD sp is the ratio of the outer diameter d o to the inner diameter d i divided by the design p des according to the equation;

RD
sp

=

d
o

d
i

*

p
des

feeding an initiator into the tubular reactor at a concentration of 0.1-50 mol/t; and
polymerizing the reaction gas in the tubular reactor at a temperature of 100-350° C. and a pressure of 180-340 MPa.

15. The process of claim 14 , wherein the specific reactor surface area A sp is 3-5 m 2 /(t/h).

16. The process of claim 14 , wherein the specific reactor surface area A sp is 3.5-4.5 m 2 /(t/h).

17. The process of claim 14 , further comprising:
feeding a 30-90% by weight portion of the reaction gas to an inlet of the tubular reactor; and
feeding a 10-70% by weight portion of the reaction gas to one or more side streams of the tubular reactor downstream of the inlet of the tubular reactor.

18. The process of claim 17 , wherein the tubular reactor has an inner surface which has a surface roughness Ra of 2 μm or less, determined according to DIN EN ISO 4287:2010.

Assignees

• Basell Polyolefine Gmbh

Inventors

• Littmann Dieter
• Mohrbutter Jürgen Peter
• Mei Giulia
• Finette Andre-Armand
• Wolfram Sven Georg
• Deuerling Michael
• Khayrullin Danir
• Groos Georg
• Wolf Christoph

Classifications

• C08F110/02 Primary

  Ethene · CPC title

• B01J19/2415 Primary

  Tubular reactors · CPC title

• C08J5/18

  Manufacture of films or sheets · CPC title

• C08J2323/06

  Polyethene · CPC title

• C08F2/34

  Polymerisation in gaseous state · CPC title