System and method for polymerization

Patent metadata

Field	Value
Publication number	US-9382348-B2
Application number	US-201314079434-A
Country	US
Kind code	B2
Filing date	Nov 13, 2013
Priority date	Nov 13, 2013
Publication date	Jul 5, 2016
Grant date	Jul 5, 2016

Abstract

Techniques are provided for polymerization. A polymerization method may include polymerizing a monomer in a polymerization reactor to produce a slurry comprising polyolefin particles and a diluent, flowing the slurry out of the polymerization reactor through an outlet of the polymerization reactor, receiving the slurry from the outlet into a slurry handling system, conveying a first mixture from the slurry handling system to a diluent and monomer recovery system, and injecting steam into the first mixture downstream of the slurry handling system using a steam injection system.

First claim

What is claimed is:

1. A method, comprising:
polymerizing a monomer in a polymerization reactor to produce a slurry comprising polyolefin particles and a diluent;
discharging at least the polyolefin particles and the diluent of the slurry as an effluent from the polymerization reactor and into a slurry handling system;
conveying the effluent from the slurry handling system to a diluent and monomer recovery system, wherein the diluent and monomer recovery system includes a separation vessel configured to separate the effluent into the polyolefin particles and the diluent; and
injecting steam into the effluent downstream of the slurry handling system and upstream of the separation vessel using a steam injection system.

2. The method of claim 1 , wherein discharging at least the polyolefin particles and the diluent of the slurry as the effluent from the polymerization reactor and into the slurry handling system comprises receiving the effluent into a continuous take-off of the slurry handling system.

3. The method of claim 1 , comprising indicating a flow rate of the steam based on a measurement provided by a steam flow meter of the steam injection system.

4. The method of claim 1 , comprising using a controller to actuate a flow control valve of the steam injection system to adjust a flow rate of the steam, using the controller to actuate a pressure control valve of the steam injection system to adjust a pressure of the steam, or a combination thereof, based on a value of a polymerization characteristic.

5. The method of claim 4 , wherein the polymerization characteristic comprises a catalyst productivity, a catalyst flow rate, a catalyst concentration, a catalyst component concentration, a polymerization reactor flow rate, a polymerization reactor composition, a polymerization reactor temperature, a first output from a polymerization reactor heat balance, a second output from a polymerization reactor mass balance, an alkyl concentration, an alkyl flow rate, a polymer production rate, a polymer solids concentration, or any combination thereof.

6. The method of claim 5 , comprising using the controller to maintain the flow rate of the steam between approximately 0.001 kg/hr to 2 kg/hr when the controller determines that the catalyst productivity is between approximately 1,000 to 250,000 mass of polymer produced/mass of catalyst.

7. The method of claim 5 , comprising using the controller to maintain the flow rate of the steam between approximately 0.03 kg/hr to 8 kg/hr when the controller determines that the alkyl concentration is between approximately 1 ppm to 500 ppm.

8. The method of claim 4 , comprising using the controller to actuate the pressure control valve such that a pressure of the steam is greater than a pressure of the effluent and is between approximately 2 MPa to 5 MPa.

9. The method of claim 1 , wherein injecting the steam using the steam injection system comprises adjusting an amount of injected steam to maintain a stoichiometric deactivation ratio of water with respect to a catalyst present in the slurry, an alkyl present in the slurry, or a combination thereof.

10. The method of claim 1 , wherein injecting the steam using the steam injection system comprises adjusting an amount of injected steam to maintain an excess water ratio of less than 100% based on an amount of a catalyst present in the slurry, an amount of an alkyl present in the slurry, or both.

11. The method of claim 1 , comprising heating the effluent using an in-line flash heater of the diluent and monomer recovery system upstream of the separation vessel to generate a mixture comprising the polyolefin particles and a liquid phase, a vapor phase, or a combination thereof.

12. The method of claim 11 , comprising maintaining a temperature of the mixture at less than approximately 100 degrees Celsius using the in-line flash heater.

13. The method of claim 1 , wherein injecting steam into the effluent downstream of the slurry handling system and upstream of the separation vessel using the steam injection system comprises injecting an amount of steam sufficient to substantially stop further polymerization.

14. A system, comprising:
a polymerization reactor configured to polymerize a monomer to produce a slurry comprising polyolefin particles and diluent;
a slurry handling system configured to receive at least the polyolefin particles and the diluent of the slurry as an effluent from the polymerization reactor and configured to provide the effluent to a diluent and monomer recovery system downstream of the slurry handling system, wherein the diluent and monomer recovery system includes an in-line flash heater configured to increase a temperature of the effluent; and
one or more automation controllers configured to:
receive an input indicative of a polymerization characteristic; and
activate an output to actuate a steam injection system to inject steam into the effluent at the in-line flash heater or upstream of the in-line flash heater based at least in part on the input.

15. The system of claim 14 , comprising at least one sensor configured to measure a value of the polymerization characteristic to generate the input.

16. The system of claim 14 , wherein the polymerization characteristic comprises a catalyst productivity, a catalyst flow rate, a catalyst concentration, a catalyst component concentration, a polymerization reactor flow rate, a polymerization reactor composition, a polymerization reactor temperature, a first output from a polymerization reactor heat balance, a second output from a polymerization reactor mass balance, an alkyl concentration, an alkyl flow rate, a polymer production rate, a polymer solids concentration, or any combination thereof.

17. The system of claim 14 , wherein the steam injection system comprises a steam flow control valve configured to receive the output and adjust a flow rate of the steam in response to the output, a pressure control valve configured to receive the output and adjust a pressure of the steam in response to the output, or a combination thereof.

18. The system of claim 14 , wherein the one or more automation controllers are configured to control the steam injection system to inject the steam at a stoichiometric deactivation ratio of water with respect to a catalyst present in the slurry, an alkyl present in the slurry, or a combination thereof.

19. The system of claim 14 , wherein the one or more automation controllers are configured to control the steam injection system to inject the steam at an excess water ratio of less than 100% based on an amount of a catalyst present in the slurry, an amount of an alkyl present in the slurry, or both.

20. The system of claim 14 , wherein the amount of steam injected into the effluent is sufficient to substantially stop further polymerization.

21. A system, comprising:
a polymerization reactor configured to produce a slurry comprising polyolefin particles and a diluent;
a slurry handling system configured to receive at least the polyolefin particles and the diluent of the slurry as an effluent from the polymerization reactor and convey the effluent to a diluent and monomer recovery system through a conduit; and
a steam injection system configured to inject steam into the effluent downstream of the slurry handling system, wherein the steam injection system comprises a plurality of steam injection openings disposed along a longitudinal axis of the conduit, about a circumference of the conduit, or a combination thereof.

Assignees

• Chevron Phillips Chemical Co

Inventors

• Kufeld Scott E
• Mutchler Joel A
• Boone David S

Classifications

• B01J2208/00548

  Flow · CPC title

• C08F210/16

  Copolymers of ethene with alpha-alkenes, e.g. EP rubbers · CPC title

• B01J2208/00761

  Discharging · CPC title

• B01J2208/00787

  Bringing the solid in the form of a slurry before feeding it to the reactor · CPC title

• B01J19/06

  Solidifying liquids (making microcapsules B01J13/02) · CPC title