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

Patent metadata

Field	Value
Publication number	US-9447264-B2
Application number	US-201414203842-A
Country	US
Kind code	B2
Filing date	Mar 11, 2014
Priority date	Jun 21, 2010
Publication date	Sep 20, 2016
Grant date	Sep 20, 2016

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 system, comprising:
a loop reactor comprising a settling leg or a continuous take-off;
a pressure relief valve coupled to the loop reactor; and
a flash chamber configured to receive a discharge stream from the settling leg or the continuous take-off of the loop reactor at least during operation of the loop reactor at a pressure below a threshold pressure, wherein the flash chamber is communicatively coupled with the pressure relief valve such that activation of the pressure relief valve in response to the pressure of the loop reactor exceeding the threshold pressure results in a discharge of a slurry from the loop reactor to the flash chamber through the pressure relief valve.

2. The system of claim 1 , wherein the flash chamber is configured to separate solid and liquid components from gas components of the slurry and transmit the gas components to a flare through a flare header.

3. The system of claim 2 , comprising an accumulator coupled to a bottom of the flash chamber to facilitate gravity feed of the solid and liquid components from the flash chamber to the accumulator.

4. The system of claim 1 , wherein the flash chamber is configured to separate solid and liquid components from gas components of the slurry and transmit the gas components to a fractionation system, and wherein the fractionation system is configured to transmit at least a portion of the gas components to a flare through a flare header.

5. The system of claim 1 , comprising a control system configured to employ a plurality of interlocks to control reaction conditions of the loop reactor.

6. The system of claim 1 , wherein the pressure relief valve is positioned proximate a top of the loop reactor.

7. A method, comprising:
receiving a discharge stream from a settling leg or a continuous take-off of a loop reactor at a flash chamber at least when a pressure in the loop reactor is below a threshold pressure;
opening a pressure relief valve coupled to the loop reactor in response to the pressure within the loop reactor exceeding the threshold pressure; and
venting a slurry from the loop reactor to the flash chamber through the opened pressure relief valve.

8. The method of claim 7 , comprising:
separating solid and liquid components from gaseous components of the slurry within the flash chamber; and
transmitting the separated gaseous components from the flash chamber to a flare header coupled to a flare.

9. The method of claim 8 , comprising transmitting the solid and liquid components to an accumulator vessel coupled to the flash chamber.

10. The method of claim 9 , comprising transmitting flash gas from the accumulator vessel to the flare header.

11. The method of claim 7 , comprising:
separating solid and liquid components from gaseous components of the slurry within the flash chamber;
transmitting the separated gaseous components from the flash chamber to a fractionation system; and
transmitting at least a portion of the separated gaseous components from the fractionation system to a flare header coupled to a flare.

12. The method of claim 7 , comprising employing a plurality of interlocks to control reaction conditions of the loop reactor.

13. A system, comprising:
a loop reactor;
a pressure relief valve coupled to the loop reactor;
a relief instrument system configured to perform at least one of a high reactor pressure interlock, a high-high pressure interlock, a high pressure isolation of jacket water heating interlock, a high temperature interlock, a high deviation from reactor temperature control set point interlock, or a loss of reactor circulation pump interlock, or any combination thereof; and
a flash chamber configured to receive a discharge stream from a settling leg or a continuous take-off of the loop reactor at least during operation of the loop reactor at a pressure below a threshold pressure, wherein the flash chamber is communicatively coupled with the pressure relief valve such that activation of the pressure relief valve in response to the pressure of the loop reactor exceeding the threshold pressure results in a discharge of a slurry from the loop reactor to the flash chamber through the pressure relief valve.

14. The system of claim 13 , wherein the relief instrument system comprises an interlock configured to activate a reactor kill procedure in response to detecting that the pressure within the loop reactor is about 15% below the threshold pressure.

15. The system of claim 13 , wherein the relief instrument system comprises an interlock configured to activate an isolation of feed lines to the loop reactor by closing valves between the feed lines and the loop reactor in response to detecting that the pressure within the loop reactor is about 10% below the threshold pressure.

16. The system of claim 13 , wherein the relief instrument system comprises an interlock configured to shut off heating of a jacket water cooling system for the loop reactor in response to detecting that the pressure within the loop reactor is about 10% below the threshold pressure.

17. The system of claim 13 , wherein the relief instrument system comprises an interlock configured to isolate an ethylene feed to the loop reactor in response to detecting that at least two temperature sensors positioned throughout the loop reactor indicate a temperature of about 235° F. or higher, or in response to detecting that one valid sensor indicates a temperature of about 500 F higher than any other valid sensor.

18. The system of claim 13 , wherein the relief instrument system comprises an interlock configured to initiate a reactor kill in response to detecting that at least two temperature sensors positioned throughout the loop reactor indicate a positive temperature difference from a reactor temperature control set point.

19. The system of claim 13 , wherein the relief instrument system comprises an interlock configured to initiate a reactor kill procedure in response to detecting a loss of reactor circulation for the loop reactor.

20. The system of claim 13 , wherein the flash chamber is configured to separate solid components from gas components of the slurry and transmit the gas components to a flare through a flare header.

Assignees

• Chevron Phillips Chemical Co Lp

Inventors

• Hottovy John D
• Peacock Richard

Classifications

• B01J19/1837 Primary

  Loop-type reactors · CPC title

• C08L23/06 Primary

  Polyethylene · CPC title

• B01J2219/24

  Stationary reactors without moving elements inside · 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

• C08F210/14

  Monomers containing five or more carbon atoms · CPC title