Methods of making high selectivity facilitated transport membranes, high selectivity facilitated transport membrane elements and modules

Patent metadata

Field	Value
Publication number	US-11083992-B2
Application number	US-201916380540-A
Country	US
Kind code	B2
Filing date	Apr 10, 2019
Priority date	Sep 27, 2018
Publication date	Aug 10, 2021
Grant date	Aug 10, 2021

Abstract

A process is provided of making facilitated transport membrane comprising a relatively hydrophilic, very small pore, nanoporous support membrane, a hydrophilic polymer inside the very small nanopores on the skin layer surface of the support membrane, a thin, nonporous, hydrophilic polymer layer coated on the surface of the support membrane, and metal salts incorporated in the hydrophilic polymer layer coated on the surface of the support membrane and the hydrophilic polymer inside the very small nanopores. In addition, the process provides a new method of making facilitated transport membrane spiral wound elements or hollow fiber modules for olefin/paraffin separations, particularly for C3=/C3 and C2=/C2 separations.

First claim

The invention claimed is:

1. A method of making a facilitated transport membrane comprising
a) coating a first layer of water soluble chitosan polymer comprising ammonium groups onto a skin layer surface of a support membrane;
b) immersing the water soluble chitosan polymer layer comprising ammonium groups on said support membrane in an aqueous solution of a metal salt directly without first treating the water soluble chitosan polymer layer with a sodium hydroxide solution during said process to form the facilitated transport membrane; and
c) then removing any extra aqueous metal salt solution from the resulting facilitated transport membrane.

2. The method of claim 1 wherein said water soluble chitosan polymer layer is formed from an aqueous chitosan solution comprising 0.5 to 10 wt % chitosan and 1-2 wt % acetic acid.

3. The method of claim 1 wherein said water soluble chitosan polymer layer is coated onto said skin layer of said support membrane by a dip-coating or a meniscus coating method.

4. The method of claim 1 wherein said support membrane comprises a nanoporous support membrane and hydrophilic polymers inside the nanopores on the skin layer surface of said support membrane.

5. The method of claim 1 wherein said aqueous solution of said metal salt comprises silver nitrate in a concentration of about 0.2M to 10M.

6. The method of claim 1 wherein between said step a) and said step b) a second layer of water soluble chitosan polymer is applied on top of said first layer of water soluble chitosan polymer.

7. The method of claim 6 wherein said second layer of water soluble chitosan polymer is formed from an aqueous chitosan solution comprising 0.5 to 10 wt % chitosan and 1-2 wt % acetic acid and wherein said aqueous chitosan solution for said second layer of water soluble chitosan polymer is at the same concentration as that for said first layer of water soluble chitosan polymer or at a lower concentration.

8. The method of claim 1 wherein said facilitated transport membrane is in a form of a flat sheet or a hollow fiber.

9. The method of claim 1 wherein said aqueous metal salt solution is applied by a static solution soaking method, a pump-driven continuous solution circulation method, or a combination thereof for a period of about 5 minutes to 24 hours.

10. The method of claim 1 wherein said membrane is used to treat a gaseous feed stream comprising from 99 to 1 mole % of one or more C2-C8 olefins and from 1 to 99 mole % of one or more C1-C8 paraffins.

11. The method of claim 1 wherein said support membrane comprises a polymer selected from the group consisting of polyethersulfone (PES), a blend of PES and polyimide, cellulose acetate, cellulose triacetate, and a blend of cellulose acetate and cellulose triacetate.

12. A method of making a facilitated transport spiral wound membrane element comprising
a) winding a water soluble chitosan polymer-coated spiral wound support membrane element using a water soluble chitosan-coated flat sheet support membrane, feed spacers, permeate spacers, gas impermeable sheets marketed as Mylar® sheets, a permeate tube, and gas impermeable glue;
b) impregnating said water soluble chitosan polymer-coated spiral wound support membrane element with an aqueous metal salt solution by exposing the water soluble chitosan polymer coating layer to said aqueous metal salt solution directly without first treating the water soluble chitosan polymer coating layer with a sodium hydroxide solution; and
c) then removing the extra aqueous metal salt solution from said spiral wound element to produce said facilitated transport spiral wound membrane element.

13. The method of claim 12 wherein said metal salt is silver nitrate.

14. The method of claim 12 wherein said aqueous metal salt solution is applied by a static solution soaking method, a pump-driven continuous solution circulation method, or a combination of the two methods for a period of time in a range from 5 min to 24 hours.

15. The method of claim 12 wherein when a humidified feed stream comprising a mixture of olefins and paraffins is contacted with said facilitated transport spiral wound membrane elements made by said process, not less than 80 mole % of the olefins in said feed stream pass through said facilitated transport spiral wound membrane elements a permeate stream comprises not less than 90 mole % of olefin and not more than 10 mole % of paraffin.

16. A process of making a facilitated transport hollow fiber membrane module comprising
a) making a water soluble chitosan polymer-coated hollow fiber support membrane module using a water soluble chitosan-coated hollow fiber support membrane and gas impermeable glue;
b) impregnating said water soluble chitosan polymer-coated hollow fiber support membrane module with an aqueous metal salt solution by exposing the water soluble chitosan polymer coating layer to said aqueous metal salt solution directly without first treating the water soluble chitosan polymer coating layer with a sodium hydroxide solution; and
c) then removing the extra aqueous metal salt solution from said hollow fiber membrane module to produce said facilitated transport hollow fiber membrane module.

17. The process of claim 16 wherein said metal salt is silver nitrate.

18. The process of claim 16 wherein said aqueous metal salt solution is applied by a static solution soaking method, a pump-driven continuous solution circulation method, or a combination of the two methods for a period of time in a range from 5 min to 24 hours.

19. The process of claim 16 wherein when a humidified feed stream comprising a mixture of olefins and paraffins is contacted with said facilitated transport hollow fiber membrane modules made by said process, not less than 80 mole % of the olefins in said feed stream pass through said facilitated transport hollow fiber membrane modules a permeate stream comprises not less than 90 mole % of olefin and not more than 10 mole % of paraffin.

20. The method of claim 1 , further comprising at least one of:
sensing at least one parameter of the process and generating a signal from the sensing;
sensing at least one parameter of the process and generating data from the sensing;
generating and transmitting a signal;
generating and transmitting data.

Assignees

• Uop Llc

Inventors

• Liu Chunqing
• Karns Nicole K
• Tran Howie Q
• Liskey Carl W

Classifications

• B01D69/107

  Organic support material · CPC title

• B01D63/101

  Spiral winding · CPC title

• B01D2325/02832

  1-10 nm · CPC title

• B01D69/142

  with "carriers" · CPC title

• B01D2325/023

  Dense layer within the membrane · CPC title