CO2 CAPTURE VIA AMINE-CO2 PRODUCT PHASE SEPARATION

• US 20140178278A1
• Filed: 11/22/2013
• Published: 06/26/2014
• Est. Priority Date: 12/21/2012
• Status: Abandoned Application

• Current Assignee: ExxonMobil Research & Engineering Company (Exxon Mobil Corporation)
• Original Assignee: ExxonMobil Research & Engineering Company (Exxon Mobil Corporation)
• Inventors: Siskin, Michael, Fedich, Robert B., Thomann, Hans, Leta, Daniel, Baugh, Lisa S., Calabro, David C., Deckman, Harry W., Hanks, Patrick L., Kortunov, Pavel, McCall, Patrick P.
• Application Number:
  US14/087,377
• Publication Number:
  US 20140178278A1
• Time in Patent Office: Days
• US Class Current: 423/228
• CPC Class Codes: B01D 2252/20415 Tri- or polyamines
• CPC Class Codes: B01D 2252/20447 containing a piperazine-ring
• CPC Class Codes: B01D 2252/20484 with one hydroxyl group
• CPC Class Codes: B01D 53/1425 Regeneration of liquid absorbents
• CPC Class Codes: B01D 53/1475 Removing carbon dioxide
• CPC Class Codes: B01D 53/62 Carbon oxides
• CPC Class Codes: Y02A 50/20 Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
• CPC Class Codes: Y02C 20/40 of CO2

Abstract

Systems and methods are provided for performing CO₂ sorption and regeneration processes that can take advantage of phase changes between solutions of amine-CO₂ reaction products and precipitate slurries, where the slurry particles can include solid precipitates formed based on the amine-CO₂ reaction products. An amine solution can be used to capture CO₂ from a gas phase stream. During this initial capture process, the amine-CO₂ reaction product can remain in solution. The solution containing the amine-CO₂ reaction product can then be exposed to a set of conditions which result in precipitation of a portion of the amine-CO₂ reaction product to form a slurry. The precipitate slurry can be passed into one or more release stages where the conditions for the slurry are altered to allow for release of the CO₂.

Claims

1. A method for separating carbon dioxide from a gas stream, comprising:

contacting a gas stream containing CO₂ in a sorption zone with a sorption solution comprising an amine, the sorption solution having a total amine concentration of at least about 2.0 M, at a temperature of at least 10°

C. to sorb at least a portion of the CO₂ into the sorption solution and form a rich stream of the sorbed in the sorption solution comprising one or more amine-CO₂ reaction products dissolved in the solution;

passing the rich stream from the sorption zone to a second zone and precipitating at least a portion of the amine-CO₂ reaction products to form a precipitate slurry;

separating the precipitate slurry to form a portion enriched in precipitate solids and a first recycle stream, the first recycle stream comprising a majority of the solvent from the precipitate slurry; and

passing the portion enriched in precipitate solids to one or more regeneration zones and desorbing the sorbed CO₂ as gas to form a second recycle stream, the second recycle portion containing a lower concentration of CO₂ than the rich stream and containing an increased concentration of amine relative to the rich stream,

wherein the sorption solution comprises at least a portion of the first recycle stream and at least a portion of the second recycle stream.

2. The method of claim 1, wherein the amine comprises at least one of a sterically hindered amine or a sterically hindered secondary amine.

3. The process according to claim 1, wherein the sterically hindered amine is AMP or MAMP, the sterically hindered amine concentration in the amine solution being from about 2.5M to about 7.0M.

4. The process according to claim 1, wherein the total amine concentration in the sorption solution is at least about 2.5M.

5. The process according to claim 1, wherein the total amine concentration in the sorption solution is from about 5.0 M to about 8.0 M.

6. The process according to claim 1, wherein the CO₂ loading in the rich stream is at least about 0.4 mol CO₂ per mol of amine.

7. The process according to claim 1, wherein the CO₂ is contacted with the amine solution in the sorption zone at a temperature of about 25°

C. to about 45°

C.

8. The process according to claim 1, wherein the CO₂ is contacted with the amine solution in the sorption zone at a CO₂ partial pressure of at least about 0.025 bar (about 2.5

9. The process according to claim 1, wherein the viscosity of the rich stream is about 10 cP or less.

10. The process according to claim 1, wherein the sorbed CO₂ is desorbed from the rich stream in the one or more regeneration zones at a temperature higher than the temperature of the sorption zone.

11. The process according to claim 10, wherein the sorbed CO₂ is desorbed from the rich amine stream in at least one regeneration zone at a temperature of 95°

C. or less.

12. The process according to claim 10, wherein the sorbed CO₂ is desorbed from the rich amine stream in at least one regeneration zone at a temperature of at least about 100°

C.

13. The process according to claim 1, wherein the at least one regeneration zone comprises a flash desorption regeneration zone.

14. The process according to claim 1, wherein at least 80 wt % of the precipitate solids comprise a bicarbonate salt.

15. The process according to claim 1, wherein the sorption solution further comprises a promoter amine.

16. The process according to claim 1, wherein the CO₂-containing gas stream is contacted with the sorption solution at a temperature greater than a temperature in the seem( zone by at most 20°

C.

17. The process according to claim 1, wherein the sorption solution comprises an aqueous sorption solution, a non-aqueous sorption solution, or a combination thereof.

18. The method of claim 17, wherein the non-aqueous sorption solution comprises an amine compound containing multiple amine groups.

19. The method of claim 17, wherein the precipitate comprises carbamates formed between an amine group from a first compound and an amine group from a second compound.

20. A method for separating carbon dioxide from a gas stream, comprising:

contacting a gas stream containing CO₂ in a sorption zone with a sorption solution comprising a sterically hindered amine, the sorption solution having a total amine concentration of at least about 2.5 M, at a temperature of at least 10°

C. to sorb at least a portion of the CO₂ into the sorption solution and form a rich stream of the sorbed CO₂ in the sorption solution comprising one or more amine-CO₂ reaction products dissolved in the solution;

passing the rich stream from the sorption zone to a second zone and precipitating at least a portion of the amine-CO₂ reaction products to form a precipitate slurry;

separating the precipitate slurry to form a portion enriched in precipitate solids and a first recycle stream, the first recycle stream comprising a majority of the solvent from the precipitate slurry, at least 80 wt % of the precipitate solids comprising a bicarbonate salt; and

passing the portion enriched in precipitate solids to one or more regeneration zones and desorbing the sorbed CO₂ as gas to form a second recycle stream, the second recycle portion containing a lower concentration of CO₂ than the rich stream and containing an increased concentration of sterically hindered amine relative to the rich stream,

wherein the sorption solution comprises at least a portion of the first recycle stream and at least a portion of the second recycle stream.