Separations with ionic liquid solvents

Patent metadata

Field	Value
Publication number	US-9238193-B2
Application number	US-201313948861-A
Country	US
Kind code	B2
Filing date	Jul 23, 2013
Priority date	Jul 23, 2013
Publication date	Jan 19, 2016
Grant date	Jan 19, 2016

Abstract

Disclosed are systems and methods which provide a process stream comprising a gaseous component, capture the gaseous component from the process stream by an ionic liquid solvent of a separator, and recover a captured gaseous component from the ionic liquid solvent in a regenerator. A second gaseous component from the process stream may be captured by the ionic liquid solvent of the separator, and the second gaseous component may be recovered from the ionic liquid solvent in the regenerator. Alternatively, the second gaseous component from the process stream may be uncaptured by the ionic liquid solvent, and the uncaptured second gaseous component may be recovered from a membrane unit.

First claim

We claim:

1. A method comprising:
providing a process stream comprising an acid gas;
capturing at least a portion of the acid gas from the process stream by an ionic liquid solvent; and
recovering at least a portion of a captured acid gas from the ionic liquid solvent,
wherein the ionic liquid solvent comprises a Ag(I) salt, a Cu(I) salt, or combinations thereof.

2. The method of claim 1 , wherein the ionic liquid solvent comprises a cation and an anion; wherein the cation comprises an ethylmethylimidazolium cation, a butylmethylimidazolium cation, a butylmethylpyridinium cation, or combinations thereof; wherein the anion comprises a bis(trifluoromethanesulfonyl)amide anion, a hexafluorophosphate anion, a trifluoromethanesulfonate anion, a dicyanamide anion, a tetrafluoroborate anion, a thiocyanate anion, a nitrate anion, a sulfonate anion, a methylsulfate anion, or combinations thereof.

3. The method of claim 1 , wherein the Ag(I) salt comprises silver(I) bis(trifluoromethanesulfonyl)amide, silver(I) trifluoromethanesulfonate, silver(I) nitrate, or combinations thereof.

4. The method of claim 1 , wherein the Cu(I) salt comprises copper(I) chloride, copper(I) bromide, cuprous trifluoroacetate, copper(I) nitrate, or combinations thereof.

5. The method of claim 1 , wherein a concentration of silver, copper, or both, in the ionic liquid solvent is from 0 N to about 2 N.

6. The method of claim 1 , wherein said capturing is performed at a liquid-to-gas mass flow ratio from about 10 to about 100.

7. The method of claim 1 , wherein said capturing is performed at a temperature from about 5° C. to about 50° C.

8. The method of claim 1 , wherein the captured acid gas is recovered at a temperature from about 60° C. to about 450° C.

9. The method of claim 1 , wherein said capturing is performed at a pressure from about 100 psia to about 250 psia.

10. The method of claim 1 , wherein the captured acid gas is recovered at a pressure greater than or equal to about 14.7 psia, wherein the pressure at which the captured acid gas is recovered is about 20 psia less than the pressure at which the acid gas is captured.

11. The method of claim 1 , further comprising:
flowing the ionic liquid solvent at a flow rate which captures at least a portion of the acid gas.

12. The method of claim 1 , wherein the acid gas comprises carbon dioxide, hydrogen sulfide, or both.

13. The method of claim 1 , wherein the process stream further comprises raw natural gas, syngas, or both.

14. The method of claim 1 , wherein the acid gas is captured by absorption, adsorption, dissolution, complexation, or combinations thereof.

15. A system comprising:
a process stream comprising a gaseous component;
a separator comprising an ionic liquid solvent, wherein the separator receives the process stream, wherein the ionic liquid solvent captures at least a portion of the gaseous component;
a captured stream exiting the separator and comprising the captured gaseous component captured in the ionic liquid solvent; and
a regenerator to receive the captured stream, wherein the regenerator regenerates the ionic liquid solvent and emits at least a portion of a recovered gaseous component,
wherein the ionic liquid solvent comprises a Ag(I) salt, a Cu(I) salt, or combinations thereof.

16. The system of claim 15 , wherein the gaseous component comprises ethylene or an acid gas; wherein the recovered gaseous component comprises ethylene or an acid gas.

17. The system of claim 15 , wherein the process stream further comprises a second gaseous component, wherein at least a portion of the second gaseous component is not captured in the ionic liquid solvent, the system further comprising:
an uncaptured stream exiting the separator and comprising an uncaptured portion of the second gaseous component; and
a membrane unit to receive the uncaptured stream and to recover at least a portion of the uncaptured portion of the second gaseous components.

18. The system of claim 17 , wherein the gaseous component comprises ethylene, wherein the second gaseous components comprises isobutane.

19. The system of claim 15 , wherein the process stream further comprises a second gaseous component, wherein the ionic liquid solvent captures at least a portion of the second gaseous component.

20. The system of claim 19 , wherein at least a portion of the gaseous component is captured by the ionic liquid solvent via absorption, dissolution, adsorption, complexation, or combinations thereof; wherein at least a portion of the second gaseous component is captured by the ionic liquid solvent via absorption, dissolution, adsorption, complexation, or combinations thereof.

21. The system of claim 19 , wherein the gaseous component comprises ethylene, wherein the second gaseous component comprises isobutane.

22. The system of claim 19 , wherein the gaseous component comprises carbon dioxide; wherein the second gaseous component comprises hydrogen sulfide.

23. The system of claim 19 , wherein the regenerator emits at least a portion of a second recovered gaseous component.

24. The system of claim 23 , wherein the recovered gaseous component comprises ethylene or an acid gas, wherein the second recovered gaseous component comprises isobutane or an acid gas.

25. The system of claim 15 , wherein separator operates at a liquid-to-gas mass flow ratio from about 1 to about 350.

26. The system of claim 15 , wherein the separator operates at a liquid-to-gas mass flow ratio from about 10 to about 100.

27. The system of claim 15 , wherein the process stream further comprises a second gaseous component; wherein the ionic liquid solvent flows through the separator at a liquid-to-gas mass flow ratio such that at least a portion of the gaseous component and at least a portion of the second gaseous component are captured by the ionic liquid solvent.

28. The system of claim 15 , wherein the ionic liquid solvent comprises a cation and an anion; wherein the cation comprises an ethylmethylimidazolium cation, a butylmethylimidazolium cation, a butylmethylpyridinium cation, or combinations thereof; wherein the anion comprises a bis(trifluoromethanesulfonyl)amide anion, a hexafluorophosphate anion, a trifluoromethanesulfonate anion, a dicyanamide anion, a tetrafluoroborate anion, a thiocyanate anion, a nitrate anion, a sulfonate anion, a methylsulfate anion, or combinations thereof.

29. The system of claim 15 , wherein the Ag(I) salt comprises silver(I) bis(trifluoromethanesulfonyl)amide, silver(I) trifluoromethanesulfonate, silver(I) nitrate, or combinations thereof.

30. The system of claim 15 , wherein the Cu(I) salt comprises copper(I) chloride, copper(I) bromide, cuprous trifluoroacetate, copper(I) nitrate, or combinations thereof.

31. The method of claim 15 , wherein a concentration of silver, copper, or both, in the ionic liquid solvent is from about 0.1 N to about 5 N.

32. The method of claim 31 , wherein the concentration of silver, copper, or both, in the ionic liquid is from about 0.45 N to about 1.8 N.

33. The system of claim 15 , wherein the process stream further comprises a second gaseous component, wherein at least a portion of the second gaseous component is not captured in the ionic liquid solvent, the system further comprising:
an uncaptured stream

Assignees

• Chevron Phillips Chemical Co
• Chevron Usa Inc

Inventors

• Ji Lei
• Chang Ai-Fu
• Driver Michael S
• Timken Hye-Kyung

Classifications

• B01D53/1462

  Removing mixtures of hydrogen sulfide and carbon dioxide · CPC title

• B01D2257/304

  Hydrogen sulfide · CPC title

• B01D2257/504

  Carbon dioxide · CPC title

• B01D53/1475

  Removing carbon dioxide · CPC title

• C07C7/144

  using membranes, e.g. selective permeation · CPC title