Device and process for the direct carbon dioxide capture from air
The present invention is based on the use of surface adsorption to capture CO 2 molecules from air, without requiring the need for bulk absorption within the bulk of the sorbent. Since surface adsorption is a much faster process than bulk absorption, the present invention offers a greatly increased CO 2 capture rate, as well as a greatly improved energy efficiency, over conventional systems. The invention involves the use of a molecular monolayer of CO 2 sorbent, a process and a system for capturing CO 2 from air employing such a molecular monolayer of CO 2 sorbent.
1 . A process for capturing CO 2 from air using a device comprising a sorption chamber, a regeneration chamber and a porous support structure comprising a surface containing pores, the process comprising:
(i) providing a flow of air through the sorption chamber over the surface of the a porous support structure to obtain air depleted in CO 2 and a loaded CO 2 sorbent;
(iii) regenerating the CO 2 sorbent at the regeneration chamber to obtain a product flow comprising CO 2 and regenerated CO 2 sorbent,
wherein the pores have an interior surface coated with a molecular monolayer of CO 2 sorbent having a thickness in the range of 0.1-3 nm, while the central part of the pores is free of sorbent and open to receive gaseous molecules, wherein the CO 2 sorbent is a bicarbonate-based sorbent or an amine-based sorbent.
2 . The process according to claim 1 , wherein the process further comprises:
(ii) moving the porous support structure containing the loaded CO 2 sorbent from the sorption chamber to a regeneration chamber;
(iv) moving the porous support structure containing the regenerated CO 2 sorbent from the regeneration chamber to the sorption chamber;
and wherein steps (i)-(iv) are repeated.
3 . The process according to claim 1 , wherein step (i) has a cycle time in the range of 0.1-60 seconds and step (iii) has a cycle time in the range of 0.1-60 seconds.
4 . The process of claim 1 , wherein the molecular monolayer of CO 2 sorbent has a thickness in the range of 0.1-1 nm.
5 . A device for capturing CO 2 from air, comprising:
(a) a porous support structure comprising a surface containing pores, wherein the pores have an interior surface coated with a molecular monolayer of solid state CO 2 sorbent having a thickness in the range of 0 . 1 - 3 nm, while the central part of the pores is free of sorbent and open to receive gaseous molecules, wherein the CO 2 sorbent is a bicarbonate-based sorbent or an amine-based sorbent;
(b) at least one sorption chamber;
(c) at least one regeneration chamber;
(d) an air displacement device or suction device that enables a flow of air over the sorbent support structure through the sorption chamber;
(e) at least one outlet for discharging CO 2 , located in the regeneration chamber; and
(f) means for regenerating the sorbent in the regeneration chamber.
6 . The device according to claim 5 , wherein the pores have a diameter in the range of 1-10 nm and a length in the range of 1-10 μm.
7 . The device according to claim 5 , wherein the porous support comprises a macroporous structure layered on top of a microporous structure, optionally wherein the macroporous structure is selected from a sandwich of foils or a honeycomb structure.
8 . The device according to claim 5 , further including transporting means to shift the sorbent from absorption to regeneration phase.
9 . The device according to claim 5 , wherein means (g) are capable of heating the CO 2 sorbent when positioned within the regeneration chamber to a temperature in the range of 50-180° C.
10 . The device according to claim 5 , wherein the CO 2 sorbent is a bicarbonate-based sorbents.
11 . The device of claim 5 , wherein the molecular monolayer of CO 2 sorbent has a thickness in the range of 0.1-1 nm.
12 . A method for capturing CO 2 from air using a molecular monolayer of CO 2 sorbent comprising:
providing a porous support comprising pore walls
coated with the molecular monolayer of CO 2 sorbent, wherein the CO 2 sorbent is a bicarbonate-based sorbent or an amine-based sorbent and the molecular monolayer has a thickness in the range of 0.1-3 nm, and
contacting the porous support with a flow of air comprising CO 2 .
13 . The method of claim 12 , wherein CO 2 sorption occurs via surface adsorption and not via bulk absorption.
14 . The method of claim 12 , wherein the porous support is a microporous support.
15 . The method of claim 12 , wherein the porous support contains needle-shaped pores with a diameter in a range of 1 to 10 nm and a length in a range of 1 to 10 μm, and wherein a surface of the pores is coated with the sorbent while a central part is free of sorbent and open to receive gaseous molecules.
16 . The method of claim 12 , wherein the porous support comprises a macroporous structure layered on top of a microporous structure.
17 . The method of claim 16 , wherein the macroporous structure is a sandwich of foils or a honeycomb structure.
18 . The method of claim 17 , further comprising leading air through the macroporous structure to enable a flow of air perpendicular to the micropores of the microporous structure, such that CO 2 molecules diffuse into an interior of the pores and are adsorbed onto the sorbent therein.
19 . The method of claim 12 , wherein the molecular monolayer of CO 2 sorbent has a thickness in the range of 0.1-1 nm.