System and method for closed relief of a polyolefin loop reactor system

Patent metadata

Field	Value
Publication number	US-9718948-B2
Application number	US-201514737020-A
Country	US
Kind code	B2
Filing date	Jun 11, 2015
Priority date	Jun 21, 2010
Publication date	Aug 1, 2017
Grant date	Aug 1, 2017

Abstract

A reactor system including an enclosed pressure relief system and/or a control system. The enclosed pressure relief system including a slurry separation system communicatively coupled with a pressure relief valve coupled to a loop reactor such that activation of the pressure relief valve results in discharge of a slurry from the loop reactor to the slurry separation system, wherein the slurry separation system is capable of separating solid and liquid components from gas components of the slurry and transmitting the gas components to a flare via a flare header.

First claim

What is claimed is:

1. A method of operating a polyolefin manufacturing system, comprising:
polymerizing olefin in a first reactor to form a first polyolefin;
transferring the first polyolefin to a second reactor;
polymerizing olefin in the second reactor to form a second polyolefin;
discharging a product polyolefin from the second reactor, the product polyolefin comprising the first polyolefin and the second polyolefin; and
operating the first reactor with a first reactor pressure relief system and the second reactor with a second reactor pressure relief system, both pressure relief systems configured to discharge to a flare system;
wherein the polyolefin manufacturing system comprises a relief instrumented system (RIS) configured to direct at least one process interlock that mitigates an excess reaction of the first reactor or the second reactor, or both, as an overpressure relief.

2. The method of claim 1 , wherein the first pressure relief system comprises a first pressure relief device, and wherein the second pressure relief system comprises a second pressure relief device.

3. The method of claim 2 , wherein the first pressure relief device comprises a first pressure relief valve, and wherein the second pressure relief device comprises a second pressure relief valve.

4. The method of claim 1 , wherein the first pressure relief system comprises a first pressure relief valve and a first rupture disk, and wherein the second pressure relief system comprises a second pressure relief valve and a second rupture disk.

5. The method of claim 1 , wherein the olefin comprises ethylene, and wherein the first and second polyolefins comprises polyethylene.

6. The method of claim 1 , wherein the at least one process interlock comprises injecting a kill fluid into at least the first reactor or the second reactor.

7. The method of claim 1 , wherein the at least one process interlock comprises at least one of isolating a feed from the first reactor or isolating a feed from the second reactor.

8. The method of claim 1 , wherein the at least one process interlock comprises activating a reactor pressure kill on a feed to the first reactor or isolating a feed to the second reactor.

9. The method of claim 1 , wherein the at least one process interlock comprises two interlocks comprising one interlock to inject a kill fluid into at least one of the first reactor or the second reactor, and another interlock to isolate a first feed to the first reactor and to isolate a second feed to the second reactor.

10. The method of claim 1 , wherein the first reactor and the second reactor are each configured with a maximum allowable working pressure (MAWP) that exceeds maximum feed pressure to the first reactor and the second reactor.

11. The method of claim 1 , wherein centrifugal pumps that deliver feed to the first reactor and the second reactor are configured to deliver a maximum pressure less than a maximum allowable working pressure (MAWP) of the first reactor and the second reactor.

12. The method of claim 11 , wherein the first reactor pressure relief system is configured to discharge through a first discharge piping to a flare header of the flare system, and the second reactor pressure relief system is configured to discharge through a second discharge piping to the flare header.

13. The method of claim 1 , wherein the first reactor pressure relief system is configured to open in response to a first reactor pressure exceeding a first set pressure, and wherein the second reactor pressure relief system is configured to open in response to a second reactor pressure exceeding a second set pressure.

14. The method of claim 1 , comprising at least one of opening the first reactor pressure relief system in response to a first reactor pressure exceeding a first set pressure, or opening the second pressure relief system in response to a second reactor pressure exceeding a second set pressure.

15. The method of claim 1 , wherein the polyolefin manufacturing system further comprises a separation system configured to discharge the vapor to a flare header of the flare system.

16. The method of claim 1 , wherein the polyolefin manufacturing system further comprises a separation system comprising a vessel.

17. The method of claim 1 , wherein the polyolefin manufacturing system further comprises a separation system comprising a cyclone.

18. The method of claim 1 , wherein the at least one process interlock comprises one interlock configured to inject a kill fluid into the first reactor and into the second reactor, and a second interlock isolating a first feed to the first reactor and to isolate on a second feed to the second reactor.

19. The method of claim 1 , wherein the first reactor and the second reactor are each configured with a maximum allowable working pressure (MAWP) that exceeds a maximum feed pressure to the first reactor and the second reactor.

20. A polyolefin production system comprising:
a first reactor configured to polymerize olefin into a first polyolefin and discharge the first polyolefin to a second reactor;
the second reactor configured to polymerize olefin into a second polyolefin and discharge a product polyolefin comprising the first polyolefin and the second polyolefin;
a relief instrumented system (RIS) configured to direct at least one process interlock that mitigates an excess reaction of the first reactor and the second reactor as an overpressure relief;
a first pressure relief device disposed on the first reactor and configured to relieve to a flare system; and
a second pressure relief device disposed on the second reactor and configured to relieve to the flare system.

21. A polyolefin production system comprising:
a first reactor configured to polymerize olefin into a first polyolefin and discharge the first polyolefin to a second reactor;
the second reactor configured to polymerize olefin into a second polyolefin and discharge a product polyolefin comprising the first polyolefin and the second polyolefin;
a relief instrumented system (RIS) configured to direct at least one process interlock that mitigates an excess reaction of the first reactor and the second reactor as an overpressure relief demand;
a first pressure relief valve disposed on the first reactor and configured to relieve to a separation system; and
a second pressure relief valve disposed on the second reactor and configured to relieve to the separation system.

22. The polyolefin production system of claim 21 , wherein the separation system is configured to collect polyolefin solids.

23. The polyolefin production system of claim 21 , wherein the separation system is configured to discharge vapor to a flare system.

24. The polyolefin production system of claim 21 , wherein the separation system comprises a vessel.

25. The polyolefin production system of claim 21 , wherein the separation system comprises a cyclone.

Assignees

• Chevron Phillips Chemical Co Lp

Inventors

• Hottovy John D
• Peacock Richard

Classifications

• B01J19/1837 Primary

  Loop-type reactors · CPC title

• C08F210/14

  Monomers containing five or more carbon atoms · CPC title

• B01J19/2455

  provoking a loop type movement of the reactants (tubular loop-type reactors B01J19/2435; loop reactors having moving elements inside B01J19/1868) · CPC title

• C08L23/06 Primary

  Polyethylene · CPC title

• C08F10/00

  Homopolymers and copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond · CPC title