Method and apparatus for CO2 sequestration

1. A method for carbon dioxide sequestration comprising:

dissolving carbon dioxide into an aqueous solution to form an aqueous carbon dioxide solution defined by a mineral undersaturation level;

combining the aqueous carbon dioxide solution with a sequestration agent;

titrating a hydrating catalyst into the aqueous carbon dioxide solution such that at least within a first catalysis region a mixture of catalyst and aqueous carbon dioxide solution is formed, said first catalysis region encompassing a second interfacial catalysis region located within the laminar boundary layer at the interface between the mixture and the carbonate sequestration agent; and

reacting the aqueous carbon dioxide solution with the catalyst within the first catalysis region to produce protons in proximity to the second interfacial catalysis region such that the protons dissolve the sequestration agent;

reacting the carbon dioxide within the aqueous carbon dioxide solution with the dissolved sequestration agent within the second interfacial catalysis region to produce an effluent comprising at least bicarbonate; and

wherein within the second interfacial catalysis region the dissolution of the sequestration agent is enhanced such that the overall rate of dissolution of the sequestration agent within the catalytic region is higher than the rate of the uncatalyzed dissolution of the sequestration agent when exposed to an aqueous carbon dioxide solution having the same mineral undersaturation level.

2. The method of claim 1 , wherein the sequestration agent is selected from the group consisting of a metal carbonate, or a silicate mineral.

3. The method of claim 1 , wherein the sequestration agent is calcium carbonate and the catalyst is one of either carbonic anhydrase or a carbonic anhydrase analog.

4. The method of claim 1 , wherein the overall rate of dissolution of the carbonate sequestration agent is at least an order of magnitude higher than the rate of the uncatalyzed dissolution of the carbonate sequestration agent when exposed to an aqueous carbon dioxide solution having the same mineral undersaturation level.

5. The method of claim 1 , wherein the mineral undersaturation level is held at less than 0.5.

6. The method of claim 1 , further comprising placing at least the first catalysis region and the second interfacial catalysis region under a pressure of at least 500 psi such that the dissolution of the sequestration agent is increased relative to the unpressurized dissolution rate of the sequestration agent at the same mineral undersaturation.

7. The method of claim 1 , further comprising maintaining at least the second interfacial catalysis region at a temperature no greater than 200° C.

8. The method of claim 1 , further comprising reacting with a condition agent the aqueous solution to reduce surface poisoning ions in the aqueous carbon dioxide solution.

9. The method of claim 1 , wherein the aqueous solution has a circum-neutral pH.

10. The method of claim 1 , wherein the aqueous solution is a brine solution.

11. The method of claim 1 , wherein the aqueous carbon dioxide solution is combined in measured aliquots such that the mineral undersaturation level is maintained at a constant level.

12. The method of claim 1 , further comprising stirring the aqueous solution within at least the first catalysis region such that a mixing zone forms wherein the aqueous carbon dioxide solution and catalyst intermingle and wherein the mixing zone is within the first catalysis region.

13. The method of claim 12 , wherein the stirring forms a diffusion boundary layer around the second interfacial catalysis region the diffusion boundary defining a volume around the interfacial region of the sequestration agent on the order of 10 microns.

14. The method of claim 1 , further comprising roughening the surface of the sequestration agent such that the grain size of the sequestration agent is no greater than 100 μm.

15. The method of claim 1 , further comprising collecting and filtering the effluent from the reaction to capture at least one of catalyst or unreacted aqueous carbon dioxide solution; and

reintroducing the catalyst and unreacted aqueous carbon dioxide solution into the first catalysis region.

16. The method of claim 1 , wherein the catalyst operates to at least catalyze the protolysis of water in the aqueous solution and hydrate the CO 2 within the solution.

17. The method of claim 1 , wherein the rate of dissolution is diffusion rate limited.

18. The method of claim 1 , wherein at least one of either the pressure is increased or the temperature is decreased to increase mineral undersaturation.

19. An apparatus for sequestering carbon dioxide, comprising:

at least one reactor vessel defining an enclosed volume;

at least one source of a catalyst, a sequestration agent, a CO 2 gas, and an aqueous solution;

at least one input in fluid communication between the at least one source and the enclosed volume of the at least one reactor vessel; and

at least one output in fluid communication with the enclosed volume of the at least one reactor vessel;

wherein the at least one input is arranged such that the CO 2 gas and aqueous solution combine to form an aqueous carbon dioxide solution, and wherein the aqueous carbon dioxide solution and catalyst are delivered as a mixture within the enclosed volume of the at least one reactor within a first catalytic region encompassing a second interfacial catalytic region disposed about the sequestration agent and being located within a laminar flow boundary at the interface between the mixture and the carbonate sequestration agent.

20. The apparatus of claim 19 , wherein at least one of the sequestration agent and catalyst is physically confined within the first catalytic region.