Siloxane hybrid membranes for enhanced natural gas liquid recovery
This disclosure relates to functionalized polyhedral oligomeric silsesquioxanes (POSS) and polymeric membranes containing the functionalized POSS. This disclosure also relates to methods of using the membranes for natural gas liquid recovery, such as removal and recovery of C 3+ hydrocarbons from natural gas.
1. A compound of Formula (I):
wherein:
each R is independently selected from H and —(C 2 -C 11 alkyl)-Si—(O—(C 1 -C 3 alkyl)) 3 ; and
the compound of Formula (I) comprises a ratio of H to —(C 2 -C 11 alkyl)-Si—(O—(C 1 -C 3 alkyl)) 3 of 1:3, 1:1, or 3:1.
2. The compound of claim 1 , wherein —(C 2 -C 11 alkyl)-Si—(O—(C 1 -C 3 alkyl)) 3 is —(CH 2 ) 2 —Si—(O—(CH 3 )) 3 .
3. The compound of claim 2 , wherein the ratio of H to —(CH 2 ) 2 —Si—(O—(CH 3 )) 3 is 3:1.
4. The compound of claim 1 , having the structure:
5. An organic-inorganic hybrid membrane comprising:
a compound of Formula (I):
wherein each R is independently selected from H and —(C 2 -C 11 alkyl)-Si—(O—(C 1 -C 3 alkyl)) 3 , and wherein the compound of Formula (I) comprises a ratio of H to —(C 2 -C 11 alkyl)-Si—(O—(C 1 -C 3 alkyl)) 3 of 1:3, 1:1, or 3:1;
vinylmethylsiloxane terpolymers; and
silanol functional polymer;
wherein the compound of Formula (I), the vinylmethylsiloxane terpolymers, and the silanol functional polydimethylsiloxane are crosslinked.
6. The membrane of claim 5 , wherein the membrane is cast on a polyacrylonitrile (PAN) support.
7. The membrane of claim 5 , wherein —(C 2 -C 11 alkyl)-Si—(O—(C 1 -C 3 alkyl)) 3 is —(CH 2 ) 2 —Si—(O—(CH 3 )) 3 .
8. The membrane of claim 7 , wherein the ratio of H to —(CH 2 ) 2 —Si—(O—(CH 3 )) 3 is 3:1.
9. The membrane of claim 5 , wherein the compound of Formula (I) is a compound having the structure:
10. The membrane of claim 5 , wherein the vinylsiloxane terpolymer is selected from a vinylmethylsiloxane-octylmethylsiloxane-dimethylsiloxane terpolymer and a vinylmethylsiloxane-phenylmethylsiloxane-dimethylsiloxane terpolymer.
11. The membrane of claim 10 , wherein the vinylsiloxane terpolymer is a vinylmethylsiloxane-octylmethylsiloxane-dimethylsiloxane terpolymer, having a (VinylMeSiO) p (Me 2 SiO) m (R 1 MeSiO) n backbone.
12. The membrane of claim 11 , wherein the vinylmethylsiloxane-octylmethylsiloxane-dimethylsiloxane terpolymer contains about 1% to about 5% vinylmethylsiloxane and about 20% to about 40% octylmethylsiloxane.
13. The membrane of claim 10 , wherein the vinylsiloxane terpolymer is a vinylmethylsiloxane-phenylmethylsiloxane-dimethylsiloxane terpolymer, having a (VinylMeSiO) p (PhMeSiO) m (R 1 MeSiO) n backbone.
14. The membrane of claim 13 , wherein the vinylmethylsiloxane-phenylmethylsiloxane-dimethylsiloxane terpolymer contains about 1% to about 5% vinylmethylsiloxane and about 20% to about 40% phenylmethylsiloxane.
15. The membrane of claim 10 , wherein the vinylsiloxane terpolymer has a molecular weight of about 2,500 Da to about 3,000 Da or about 10,000 Da to about 12,000 Da or about 50,000 Da.
16. The membrane of claim 5 , wherein the silanol functional polymer is a silanol functional polydimethylsiloxane.
17. The membrane of claim 16 , wherein the silanol functional polymer is a silanol functional polymer having a OH(Me 2 SiO) x (R 2 R 1 SiO) y OH backbone.
18. The membrane of claim 5 , wherein the silanol functional polymer is selected from silanol-terminated polydimethylsiloxane, silanol-terminated polydiphenylsiloxane, silanol-terminated diphenylsiloxane-dimethylsiloxane copolymer containing diphenylsiloxane monomers, silanol-terminated polytrifluoropropylmethylsiloxane, and combinations thereof.
19. The membrane of claim 5 , wherein the silanol functional polymer has a molecular weight of about 550 Da to about 1,200 Da or about 1,000 Da to about 1,400 Da or about 900 Da to about 50,000 Da or about 400 Da to about 140,000 Da.
20. The membrane of claim 5 , wherein the membrane has a crosslinking density of about 10×10 −5 mol/mL to about 30×10 −5 mol/mL.
21. The membrane of claim 5 , wherein the membrane has a C 3 H 8 /CH 4 single gas selectivities (αC 3 H 8 /CH 4 ) of about 7 to about 25 at feed temperature of 25° C. and feed pressure of 1 bar.
22. The membrane of claim 5 , wherein the membrane has a C 4 H 10 /CH 4 single gas selectivities (αC 4 H 10 /CH 4 ) of about 25 to about 100 at feed temperature of 25° C. and feed pressure of 1 bar.
23. A method of separating C 3+ hydrocarbons from natural gas, comprising:
providing an organic-inorganic hybrid membrane comprising:
a compound of Formula (I):
wherein each R is independently selected from H and —(C 2 -C 11 alkyl)-Si—(O—(C 1 -C 3 alkyl)) 3 , and wherein the compound of Formula (I) comprises a ratio of H to —(C 2 -C 11 alkyl)-Si—(O—(C 1 -C 3 alkyl)) 3 of 1:3, 1:1, or 3:1;
vinylmethylsiloxane terpolymers; and
silanol functional polymer;
wherein the compound of Formula (I), the vinylmethylsiloxane terpolymers, and the silanol functional polydimethylsiloxane are crosslinked;
introducing a natural gas stream to the membrane; and
separating the C 3+ hydrocarbons from the natural gas.
24. The method of claim 23 , wherein the compound of Formula (I) is a compound having the structure:
25. The method of claim 23 , wherein the vinylsiloxane terpolymer is selected from a vinylmethylsiloxane-octylmethylsiloxane-dimethylsiloxane terpolymer and a vinylmethylsiloxane-phenylmethylsiloxane-dimethylsiloxane terpolymer.
26. The method of claim 25 , wherein the vinylsiloxane terpolymer is a vinylmethylsiloxane-octylmethylsiloxane-dimethylsiloxane terpolymer having a (VinylMeSiO) p (Me 2 SiO) m (R 1 MeSiO) n backbone.
27. The method of claim 26 , wherein the vinylmethylsiloxane-octylmethylsiloxane-dimethylsiloxane terpolymer contains about 1% to about 5% vinylmethylsiloxane and about 20% to about 40% octylmethylsiloxane.
28. The membrane of claim 25 , wherein the vinylsiloxane terpolymer is a vinylmethylsiloxane-phenylmethylsiloxane-dimethylsiloxane terpolymer, having a (VinylMeSiO) p (PhMeSiO) m (R 1 MeSiO) n backbone.
29. The membrane of claim 28 , wherein the vinylmethylsiloxane-phenylmethylsiloxane-dimethylsiloxane terpolymer contains about 1% to about 5% vinylmethylsiloxane and about 20% to about 40% phenylmethylsiloxane.
30. The method of claim 25 , wherein the vinylsiloxane terpolymer has a molecular weight of about 2,500 Da to about 3,000 Da or about 10,000 Da to about 12,000 Da or about 50,000 Da.
31. The method of claim 23 , wherein the silanol functional polymer is a silanol functional polydimethylsiloxane.
32. The method of claim 31 , wherein the silanol functional polymer is a silanol functional polymer having a OH(Me 2 SiO) x (R 2 R 1 SiO) y OH backbone.
33. The method of claim 23 , wherein the silanol functional polymer is selected from silanol-terminated polydimethylsiloxane, silanol-terminated polydiphenylsiloxane, silanol-terminated diphenylsiloxane-dimethylsiloxane copolymer containing diphenylsiloxane monomers, silanol-terminated polytrifluoropropylmethylsiloxane, and combinations thereof.
34. The method of claim 23 , wherein the silanol functional polymer has a molecular weight of about 550 Da to about 1,200 Da or about 1,000 Da to about 1,400 Da or about 900 Da to about 50,000 Da or about 400 Da to about 140,000 Da.
35. The method of claim 23 , wherein the membrane has a crosslinking density of about 10×10 −5 mol/mL to about 30×10 −5 mol/mL.
36. The method of claim 23 , wherein the C 3+ hydrocarbons are more permeable through the membrane than methane.