METHODS FOR APPLYING MICROCHANNELS TO SEPARATE METHANE USING LIQUID ABSORBENTS, ESPECIALLY IONIC LIQUID ABSORBENTS FROM A MIXTURE COMPRISING METHANE AND NITROGEN

• US 20090071335A1
• Filed: 08/01/2008
• Published: 03/19/2009
• Est. Priority Date: 08/01/2007
• Status: Active Grant

• Current Assignee: Velocys Incorporated (Velocys PLC)
• Original Assignee: Velocys Incorporated (Velocys PLC)
• Inventors: Litt, Robert D., Simmons, Wayne W., Perry, Steven, Silva, Laura J., Fanelli, Maddalena, Dongming, Qiu, Lamont, Micheal Jay, Tonkovich, Anna Lee Y.
• Granted Patent: US 8,029,604 B2
• Time in Patent Office: Days
• US Class Current: 95/172
• CPC Class Codes: B01D 19/00 Degasification of liquids
• CPC Class Codes: B01D 2256/10 Nitrogen
• CPC Class Codes: B01D 53/1487 Removing organic compounds
• CPC Class Codes: B01D 53/18 Absorbing units; Liquid distributors therefor B01D3/16, B01D3/26, B01D3/30 take precedence; packing elements B01J19/30, B01J19/32
• CPC Class Codes: C01B 2203/0415 Purification by absorption in liquids
• CPC Class Codes: C01B 2203/0475 the impurity being carbon dioxide
• CPC Class Codes: C01B 2203/048 the impurity being an organic compound
• CPC Class Codes: C01B 3/52 by contacting with liquids; Regeneration of used liquids C01B3/508 takes precedence

Abstract

Methods of using microchannel separation systems including absorbents to improve thermal efficiency and reduce parasitic power loss. Energy is typically added to desorb methane and then energy or heat is removed to absorb methane using a working solution. The working solution or absorbent may comprise an ionic liquid, or other fluids that demonstrate a difference in affinity between methane and nitrogen in a solution.

Claims

1. A method for separating gaseous components comprising the steps of:

contacting a gaseous mixture including methane with an ionic liquid by flowing the gaseous mixture and the ionic liquid through a microchannel;

absorbing at least a portion of the methane of the gaseous mixture by the ionic liquid, thereby creating a resultant mixture including a resultant gas and the ionic liquid;

directing the resultant gas away from the ionic liquid; and

desorbing at least a portion of the methane from the ionic liquid by changing the temperature of the ionic liquid.

2. The method of claim 1, wherein the step of desorbing at least a portion of the methane includes raising the temperature of the ionic liquid.

3. The method of claim 1, wherein the step of desorbing at least a portion of the methane includes lowering the temperature of the ionic liquid.

4. The method of claim 1, wherein the step of desorbing at least a portion of the methane includes lowering the pressure of the ionic liquid.

5. The method of claim 1, further comprising the step of changing the temperature of the ionic liquid prior to the step of absorbing at least a portion of the methane.

6. The method of claim 1, wherein the step of desorbing at least a portion of methane includes raising the pressure of the ionic liquid.

7. The method of claim 6, wherein the step of changing the temperature of the ionic liquid includes lowering the temperature of the ionic liquid.

8. The method of claim 6, wherein the step of changing the temperature of the ionic liquid includes raising the temperature of the ionic liquid.

9. The method of claim 6, wherein thermal energy extracted from the ionic liquid in one of the desorbing and changing the temperature steps is supplied to the ionic liquid in the other of the desorbing and changing the temperature steps.

10. The method of claim 1, wherein the microchannel includes at least one flow mixing feature.

11. The method of claim 10, wherein the flow mixing feature includes a porous packed bed including at least one of rings and spheres.

12. The method of claim 10, wherein the flow mixing feature includes at least one of a porous foam, felt, wad and other porous structure continuous for at least a length greater than a length of three hydraulic diameters of the microchannel, wherein the porosity is less than one.

13. The method of claim 1, wherein the contacting step includes flowing the gaseous mixture and the ionic liquid co-currently through the microchannel.

14. The method of claim 1, wherein the contacting step includes flowing the gaseous mixture counter-currently to the ionic liquid through the microchannel.

15. The method of claim 1, wherein the microchannel includes at least one of a foam, wad, and mesh.

16. The method of claim 15, wherein the flowing step includes wetting the foam, wad, or mesh with the ionic liquid.

17. The method of claim 15, wherein the microchannel includes a foam constructed from at least one of aluminum, carbon, copper, nickel, stainless steel, and silicon carbide.

18. The method of claim 15, wherein the microchannel includes a foam coated with a material to increase the wetting over the underlying material.

19. The method of claim 15, wherein the microchannel includes a plurality of foams having different pore densities.

20. The method of claim 1, wherein the gaseous mixture includes methane and nitrogen.

21. The method of claim 20, wherein the resultant gas includes nitrogen.

22. The method of claim 1, wherein the gaseous mixture includes carbon dioxide.

23. A processing system comprising:

a first microchannel including a first absorbent inlet, a first absorbent outlet, a feed stream inlet, and a first resultant gas outlet;

a second microchannel including a second absorbent inlet, a second absorbent outlet, and a second resultant gas outlet, the second microchannel being arranged in a counterflow arrangement relative to the first microchannel;

an absorbent circulating through the first microchannel and the second microchannel;

wherein the absorbent has a temperature T1 at the first inlet, a temperature T2 and the first outlet, a temperature T3 at the second inlet, and a temperature T4 at the second outlet;

wherein at least one of the following conditions is satisfied;

T2 is greater than T3 and T1 is greater than T4.

24. The processing device of claim 23, wherein the absorbent has a Henry'"'"'s law constant that increases with temperature;

and wherein T4 is greater than T2.

25. The processing device of claim 23, wherein the feed stream inlet receives a mixture including methane and nitrogen, the first resultant gas outlet exhausts a first resultant gas having a higher concentration of nitrogen than the mixture, and the second resultant gas outlet exhausts a second resultant gas having a higher concentration of methane than the mixture.

26. The processing device of claim 23, wherein a difference between T1 and T4 is less than 10 C.

27. The processing device of claim 26, wherein the difference between T1 and T4 is less than 5 C.

28. The processing device of claim 27, wherein the difference between T1 and T4 is less than 2 C.

29. The processing device of claim 28, wherein the difference between T1 and T4 is less than 1 C.

30. The processing device of claim 23, wherein a difference between T2 and T3 is less than 10 C.

31. The processing device of claim 30, wherein the difference between T2 and T3 is less than 5 C.

32. The processing device of claim 31, wherein the difference between T2 and T3 is less than 2 C.

33. The processing device of claim 32, wherein the difference between T2 and T3 is less than 1 C.

34. A processing system comprising:

a first microchannel including a first absorbent inlet, a first absorbent outlet, a feed stream inlet, and a first resultant gas outlet;

a second microchannel including a second absorbent inlet, a second absorbent outlet, and a second resultant gas outlet, the second microchannel being arranged in a counterflow arrangement relative to the first microchannel;

an absorbent circulating through the first microchannel and the second microchannel;

wherein the absorbent has a temperature T1 at the first inlet, a temperature T2 at the first outlet, a temperature T3 at the second inlet, and a temperature T4 at the second outlet;

wherein at least one of the following conditions is satisfied;

T3 is greater than T2, T4 is greater than T1, and T2 is greater than T4.

35. The processing device of claim 34, wherein a difference between T1 and T4 is less than 10 C.

36. The processing device of claim 35, wherein the difference between T1 and T4 is less than 5 C.

37. The processing device of claim 36, wherein the difference between T1 and T4 is less than 2 C.

38. The processing device of claim 37, wherein the difference between T1 and T4 is less than 1 C.

39. The processing device of claim 34, wherein a difference between T2 and T3 is less than 10 C.

40. The processing device of claim 39, wherein the difference between T2 and T3 is less than 5 C.

41. The processing device of claim 40, wherein the difference between T2 and T3 is less than 2 C.

42. The processing device of claim 41, wherein the difference between T2 and T3 is less than 1 C.