Direct gas capture systems and methods of use thereof

Patent metadata

Field	Value
Publication number	US-11097221-B2
Application number	US-201916593197-A
Country	US
Kind code	B2
Filing date	Oct 4, 2019
Priority date	Oct 5, 2018
Publication date	Aug 24, 2021
Grant date	Aug 24, 2021

Abstract

The present disclosure provides systems and methods that combine direct capture of one or more moieties from a gaseous mixture with one or both of calcium oxide production and power production. The systems and methods can utilize combinations of a capture unit, a regeneration unit, a calcination unit, a slaking unit, a heat exchange unit, a separation unit, and a power production unit. The present disclosure provides the ability to remove carbon dioxide and other moieties from air or other gaseous mixtures in a truly carbon negative manner by utilizing electricity from a power production unit that is operated in a carbon neutral or carbon negative manner and simultaneously provide useful products, such as calcium oxide and calcium hydroxide.

First claim

The invention claimed is:

1. A method for direct capture of carbon dioxide from air with simultaneous power production and generation of one or both of calcium oxide and calcium hydroxide, the method comprising:
contacting air with an alkali solvent in a contacting unit under conditions effective to react the alkali solvent with carbon dioxide in the air and form an intermediate product incorporating the carbon dioxide removed from the air;
regenerating the alkali solvent in a regenerating unit by reacting the intermediate product incorporating the carbon dioxide with calcium hydroxide to form a regenerated alkali solvent and form calcium carbonate;
heating the calcium carbonate in a calcination unit to form calcium oxide and provide a heated gas stream;
reacting a portion of the calcium oxide with water in a slaking unit to form calcium hydroxide, at least a portion which is passed to the regenerating unit;
withdrawing heat from the heated gas stream in a heat exchange unit to form a cooled gas stream; and
using at least a portion of the heat withdrawn from the heated gas stream in the heat exchange unit to heat one or more streams in a semi-closed loop power production unit configured for repeated compression and expansion of a carbon dioxide working fluid.

2. The method of claim 1 , wherein the alkali solvent comprises one or both of potassium hydroxide and sodium hydroxide.

3. The method of claim 2 , wherein the intermediate product comprises one or both of potassium carbonate and sodium carbonate.

4. The method of claim 1 , comprising recycling at least a portion of the regenerated alkali solvent back to the contacting unit.

5. The method of claim 1 , wherein heating the calcium carbonate in the calcination unit comprises injecting a fuel and an oxidant into the calcination unit under conditions effective to at least partially combust the fuel to produce heat.

6. The method of claim 1 , further comprising injecting a stream of makeup calcium carbonate into the calcination unit.

7. The method of claim 1 , further comprising exporting a portion of the calcium oxide formed in the calcination unit as a calcium oxide product stream.

8. The method of claim 1 , wherein the calcination unit is operated at a temperature of 700° C. to about 1300° C.

9. The method of claim 1 , further comprising passing the heated gas stream or the cooled gas stream to a separation unit and forming a substantially pure stream of carbon dioxide.

10. The method of claim 9 , further comprising compressing at least a portion of the substantially pure stream of carbon dioxide to a pressure of about 20 bar to about 200 bar.

11. The method of claim 1 , further comprising cooling at least a portion of the formed calcium oxide prior to reacting a portion of the calcium oxide with water to form calcium hydroxide.

12. The method of claim 1 , wherein the slaking unit is operated in a temperature range of about 125° C. to about 600° C.

13. The method of claim 1 , wherein at least a portion of the heat that is withdrawn from the heated gas stream in the heat exchange unit is used for pre-heating the calcium carbonate entering the calcination unit.

14. The method of claim 13 , wherein the calcium carbonate is heated up to a temperature of about 400° C. to about 800° C.

15. The method of claim 1 , further comprising using one or more exhaust streams in a gas phase or a solid phase from the slaking unit to transfer heat to one or more streams in the semi-closed loop power production unit configured for repeated compression and expansion of a carbon dioxide working fluid.

16. The method of claim 1 , further comprising using electricity generated in the semi-closed loop power production unit configured for repeated compression and expansion of a carbon dioxide working fluid to supply at least a portion of an electrical load requirement necessary for operation of at least the contacting unit.

17. The method of claim 1 , wherein the contacting unit includes a solid state absorbent unit, and wherein the air used in the contacting unit is first passed through the solid state absorbent unit.

18. The method of claim 1 , wherein the air used in the contacting unit is first compressed in an air separation unit prior to being passed to the contacting unit.

19. The method of claim 18 , wherein the air separation unit is used to produce oxygen for one or both of the semi-closed loop power production unit configured for repeated compression and expansion of a carbon dioxide working fluid and the calcination unit.

20. The method of claim 1 , wherein the semi-closed loop power production unit configured for repeated compression and expansion of a carbon dioxide working fluid includes a power production turbine, and wherein all or part of an exhaust stream from the power production turbine is used to provide heating for the calcination unit.

Assignees

• 8 Rivers Capital Llc

Inventors

• Lu Xijia
• Fetvedt Jeremy Eron
• Forrest Brock Alan
• Brown Jr Glenn William
• Rafati Mohammad
• Martin Scott Thomas

Classifications

• B01D53/96

  Regeneration, reactivation or recycling of reactants · CPC title

• Y02A50/20

  Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters · CPC title

• B01D2251/404

  of calcium · CPC title

• B01D53/78 Primary

  with gas-liquid contact · CPC title

• C01B32/50

  Carbon dioxide · CPC title