Rate enhancement of CO2 absorption in aqueous potassium carbonate solutions by an ammonia-based catalyst

Patent metadata

Field	Value
Publication number	US-9339757-B2
Application number	US-201514712180-A
Country	US
Kind code	B2
Filing date	May 14, 2015
Priority date	Nov 15, 2012
Publication date	May 17, 2016
Grant date	May 17, 2016

Abstract

The technical field of the invention is CO 2 capture and sequestration, as well as gas separation and purification technologies. In an aspect is a process for capturing purified CO 2 from a CO 2 -containing gas, comprising steps: (a) contacting in an absorber column the CO 2 -containing gas with an absorption solution comprising water, ammonia, and potassium carbonate, to enable adsorption of CO 2 , thereby producing a CO 2 -depleted gas and a CO 2 -rich solution; and (b) subjecting the CO 2 -rich solution to desorption conditions in a regeneration column producing a purified CO 2 gas stream and a CO 2 -depleted solution.

First claim

What is claimed is:

1. A process for capturing purified CO 2 from a CO 2 -containing gas, comprising steps:
(a) contacting in an absorber column the CO 2 -containing gas with an absorption solution comprising water, ammonia, and potassium carbonate, to enable adsorption of CO 2 , thereby producing a CO 2 -depleted gas and a CO 2 -rich solution; and
(b) subjecting the CO 2 -rich solution to desorption conditions in a regeneration column producing a purified CO 2 gas stream and a CO 2 -depleted solution.

2. The process of claim 1 , wherein the absorption solution in a first section of the absorber column comprises a dissolved ammonia to total potassium ratio greater than 1:1, and wherein the absorption solution in a second section of the absorber column comprises a dissolved ammonia to total potassium ratio less than 1:1.

3. The process of claim 1 , wherein the absorption solution in a third section of the absorber column has a lower ammonia concentration relative to the absorption solution in a first section of the absorber column and a higher ammonia concentration relative to the absorption solution in a second of the absorber column.

4. The process of claim 1 , wherein the absorption solution comprises ammonia, ammonium carbonate, ammonium bicarbonate, potassium carbonate, and potassium bicarbonate.

5. The process of claim 1 , further comprising pumping the CO 2 -depleted solution to the absorber column.

6. The process of claim 1 , further comprising the steps:
(c) pumping the CO 2 -depleted solution from a first section of the regeneration column to a flash chamber, wherein the flash chamber removes ammonia from the CO 2 -depleted solution to form an ammonia-depleted CO 2 -depleted solution; and
(d) pumping the ammonia-depleted CO 2 -depleted solution to the absorber column.

7. The process of claim 1 , wherein the regeneration column comprises a regeneration solution, and a temperature gradient exists within the regeneration column such that the temperature of the regeneration solution at a second section of the regeneration column is lower than the temperature of the regeneration solution at a first section of the regeneration column.

8. The process of claim 1 , wherein the desorption conditions comprise a temperature above 30° C. and a pressure above 5 bar.

9. The process of claim 1 , wherein the absorption solution in a bottom section of the absorber column is maintained at a temperature of between 20-40° C.

10. The process of claim 1 , further comprising pumping the CO 2 -depleted solution to the absorber column, and wherein the absorption solution comprises ammonia, ammonium carbonate, ammonium bicarbonate, potassium carbonate, and potassium bicarbonate.

11. The process of claim 1 , further comprising pumping the CO 2 -depleted solution to the absorber column, and wherein the regeneration column comprises a regeneration solution, and a temperature gradient exists within the regeneration column such that the temperature of the regeneration solution at a second section of the regeneration column is lower than the temperature of the regeneration solution at a first section of the regeneration column.

12. The process of claim 1 , further comprising pumping the CO 2 -depleted solution to the absorber column, and wherein the absorption solution in a first section of the absorber column comprises a dissolved ammonia to total potassium ratio greater than 1:1, and wherein the absorption solution in a second section of the absorber column comprises a dissolved ammonia to total potassium ratio less than 1:1.

13. The process of claim 1 , further comprising the steps:
(c) pumping the CO 2 -depleted solution from a first section of the regeneration column to a flash chamber, wherein the flash chamber removes ammonia from the CO 2 -depleted solution to form an ammonia-depleted CO 2 -depleted solution; and
(d) pumping the ammonia-depleted CO 2 -depleted solution to the regeneration column,
and wherein the absorption solution comprises ammonia, ammonium carbonate, ammonium bicarbonate, potassium carbonate, and potassium bicarbonate.

14. The process of claim 1 , further comprising the steps:
(c) pumping the CO 2 -depleted solution from a first section of the regeneration column to a flash chamber, wherein the flash chamber removes ammonia from the CO 2 -depleted solution to form an ammonia-depleted CO 2 -depleted solution; and
(d) pumping the ammonia-depleted CO 2 -depleted solution to the regeneration column,
and wherein the absorption solution in a first section of the absorber column comprises a dissolved ammonia to total potassium ratio greater than 1:1, and wherein the absorption solution in a second section of the absorber column comprises a dissolved ammonia to total potassium ratio less than 1:1.

15. A system for capturing purified CO 2 comprising: an absorber column containing an absorption solution comprising water, ammonia, and potassium carbonate; a regeneration column in fluid communication with the absorber column; and an optional flash chamber in fluid communication with the regeneration column and in fluid communication with the absorber column.

Assignees

• Stanford Res Inst Int

Inventors

• Jayaweera Indira S
• Jayaweera Palitha
• Krishnan Gopala N
• Sanjurjo Angel

Classifications

• B01D53/62 Primary

  Carbon oxides · CPC title

• B01D2257/504

  Carbon dioxide · CPC title

• Y02C10/04

  Cross-Sectional Technologies · mapped topic

• B01D53/1475

  Removing carbon dioxide · CPC title

• B01D2251/306

  of potassium · CPC title