Reactor jacket design

Patent metadata

Field	Value
Publication number	US-11478768-B2
Application number	US-201916402678-A
Country	US
Kind code	B2
Filing date	May 3, 2019
Priority date	May 3, 2019
Publication date	Oct 25, 2022
Grant date	Oct 25, 2022

Abstract

Reactor systems, reactor coolant systems, and associated processes for polymerizing polyolefins are described. The reactor systems generally include a reactor pipe and a coolant system, in which the coolant system includes a jacket pipe surrounding at least a portion of the reactor pipe to form an annulus therebetween, at least one spacer coupling the jacket to the reactor pipe, and a coolant which flows through the annulus to remove heat from the reactor pipe. At least one of the external surface of the reactor pipe, the internal surface of the jacket, and at least one spacer, are independently modified, for example by polishing, coating, or reshaping, to reduce the fluid resistance of the coolant flow through the annulus.

First claim

We claim:

1. A reactor system comprising:
a reactor pipe having an external surface characterized by an unmodified surface roughness; and
a coolant system, the coolant system comprising:
a jacket having an internal surface characterized by an unmodified surface roughness, the jacket spaced apart from and surrounding at least a portion of the reactor pipe to form an annulus between the internal surface of the jacket and the external surface of the reactor pipe,
a coolant which flows through the annulus to remove heat from the reactor pipe, and
at least one spacer having a leading edge and a trailing edge with respect to the coolant flow and characterized by an unmodified surface roughness, the spacer coupling the jacket to the reactor pipe;

wherein the external surface of the reactor pipe, the internal surface of the jacket, the at least one spacer, or any combination thereof are independently modified to reduce the fluid resistance of the coolant flow through the annulus, and
wherein the external surface of the reactor pipe, the internal surface of the jacket, the at least one spacer, or any combination thereof are independently modified by polishing or by coating with a friction-reducing coating to reduce their unmodified surface roughness to a respective modified surface roughness (R a ).

2. The reactor system of claim 1 , wherein:
the modified surface roughness (R a ) of the external surface of the reactor pipe, the internal surface of the jacket, the at least one spacer, or any combination thereof is 0.00010 microns or less, or
the modified surface roughness (R a ) of the external surface of the reactor pipe, the internal surface of the jacket, the at least one spacer, or any combination thereof is at least 50% less than the respective unmodified surface roughness.

3. The reactor system of claim 1 , wherein the coolant system provides a total coolant pressure drop through the coolant system that is 20% lower than a corresponding total coolant pressure drop through an identical coolant system having the unmodified surface roughness.

4. The reactor system of claim 1 , wherein the at least one spacer is polished and has a drag coefficient of less than 1.5.

5. The reactor system of claim 1 , wherein the at least one spacer is modified by shaping the spacer in cross section to provide a curved or partially curved leading edge, a tapered or partially tapered trailing edge, or a combination thereof.

6. The reactor system of claim 5 , wherein the at least one spacer has a fineness ratio of at least about 2.

7. The reactor system of claim 5 , wherein the at least one spacer has a pitch of from 1 degree to 30 degrees.

8. The reactor system of claim 5 , wherein:
the leading edge of the at least one spacer comprises a radius of less than about 5.0 inches, and/or
the leading edge is shaped to reduce at least one radius by at least 30% from a 90° angle.

9. The reactor system of claim 5 , wherein the coolant system comprises a plurality of spacers configured to provide a venturi effect when the coolant flows over the plurality of spacers.

10. The reactor system of claim 5 , wherein the pressure drop across any single spacer is less than about 12% of a total coolant pressure drop through the reactor system.

11. The reactor system of claim 5 , wherein at least a portion of the plurality of spacers is modified and/or shaped to having a drag coefficient of each modified and/or shaped spacer of less than 1.28.

12. The reactor system of claim 1 , wherein at least one of the external surface of the reactor pipe and/or the internal surface of the jacket are independently further modified by the addition of one or more protrusions which extend from the internal surface of the jacket and/or the external surface of the reactor pipe into a portion of the annular space to create a venturi effect from the coolant flow.

13. The reactor system of claim 12 , wherein the at least one protrusion is shaped to provide a curved or partially curved leading edge, a tapered or partially tapered trailing edge, or both.

14. The reactor system of claim 12 , wherein the one or more protrusions comprise one or more continuous protrusions extending from the internal surface of the jacket and/or the external surface of the reactor pipe in a circular fashion.

15. The reactor system of claim 12 , wherein the one or more protrusions comprise one or more discontinuous protrusions extending from the internal surface of the jacket and/or the external surface of the reactor pipe in a non-circular and segmented fashion.

16. The reactor system of claim 15 , comprising a discontinuous protrusion extending from the internal surface of the jacket and a corresponding discontinuous protrusion extending from the external surface of the reactor pipe which are spaced at substantially the same height along the jacket and reactor pipe, respectively, to provide a venturi effect when the coolant flows between the protrusions.

17. The reactor system of claim 1 , wherein the reactor system is a loop reactor comprising a series of reactor pipe sections which form a series of legs and which form a loop.

18. The reactor system of claim 17 , wherein the reactor system has:
a production capacity of at least about 125,000 lbs/hr and/or a reactor capacity of at least about 35,000 gallons, and
a total coolant pressure drop through the coolant system of less than 15 psi and/or a coolant pressure drop per leg of the loop reactor of less than 1.4 psi.

19. The reactor system of claim 1 , wherein the reactor system has a reactor capacity of at least about 125,000 lbs/hr and a total coolant pressure drop through the reactor system is less than 15 psi, and
wherein at least a portion of the internal surface of the jacket is polished and the surface roughness (R a ) is reduced by at least 50% compared to an untreated surface roughness.

20. A method of polymerizing olefins, the method comprising contacting at least one olefin monomer with catalyst within the reactor system of claim 1 under polymerization conditions sufficient to form a polyolefin.

21. A reactor system comprising:
a loop reactor comprising a reactor pipe having an external surface and a volume of greater than about 35,000 gallons and comprising a series of reactor pipe sections which form a series of legs and which form a loop; and
a coolant system comprising:
a jacket having an internal surface, spaced apart from and surrounding at least a portion of the reactor pipe to form an annulus between the internal surface of the jacket and the external surface of the reactor pipe,
a coolant which flows through the annulus to remove heat from the reactor pipe, and
a plurality of spacers, each having a leading edge and a trailing edge with respect to the coolant flow and characterized by an unmodified surface roughness, each spacer coupling the jacket to the reactor pipe;

wherein the plurality of spacers are modified by shaping each spacer in cross section to provide a curved or partially curved leading edge, and a tapered or partially tapered trailing edge, and the total coolant pressure drop through the coolant system is less than 15 psi.

22. A reactor system comprising:
a reactor pipe having an external surface characterized by an unmodified surface roughness; and
a coolant system, the coolant system comprising:
a jacket having an internal surface characterized by an unmodified surface roughness, the jacket spaced apart from and surrounding at least a portion of the reactor

Assignees

• Chevron Phillips Chemical Co Lp

Inventors

• Gupta Anurag
• Kufeld Scott E
• Ezell Larry W
• Mcelvain Robert R
• Parrott Robert F

Classifications

• B01J8/067 Primary

  Heating or cooling the reactor (B01J8/062 takes precedence) · CPC title

• B01J2208/065

  Heating or cooling the reactor · CPC title

• B01J2208/00176

  outside the reactor · CPC title

• B01J2219/00765

  Baffles attached to the reactor wall · CPC title

• B01J8/0496

  Heating or cooling the reactor · CPC title