ROTATING CONTINUOUS MULTI-CAPTURE SYSTEMS AND APPARATUS FOR IMPROVED DIRECT AIR CAPTURE OF CARBON DIOXIDE (DAC+)

Abstract

A system and method for, removing carbon dioxide from a carbon dioxide laden gas mixture, the system comprising a group of carbon dioxide removal structures moving along a closed curve track. At one location along the track is located a desorption or regeneration box, into which each capture structure passes in order to be regenerated. The majority of the CO2 removal structures are fed ambient air, or an admixture of ambient air with a minor portion of a flue gas, and exhaust CO2-lean air. At least one selected such removal structure within each group, at a location immediately preceding its entry into the capture structure, is fed a flue gas comprising at least 4% CO2 by volume. A method for removing carbon dioxide from the atmosphere is provided utilizing a system operating in the same manner as the preceding system.

Claims

1-20. (canceled)

21. A system for removing CO.sub.2 comprising: a group of carbon dioxide removal structures, wherein each carbon dioxide removal structure comprises a porous solid substrate supported on the structure, wherein each porous substrate having a sorbent supported within its pores, wherein the sorbent being capable of adsorbing or binding to carbon dioxide; a first set of stations including the carbon dioxide removal structures, wherein the first set of stations of the carbon dioxide removal structures are configured to remove CO.sub.2 from a first gas; at least one additional station, wherein each additional station includes the carbon dioxide removal structure, wherein each carbon dioxide removal structure corresponding to the at least one additional station is configured to remove CO.sub.2 from a second gas; a sealable regeneration box for regenerating the sorbent, wherein the at least one additional station being positioned after the first set of stations and before the regeneration box; and a system for moving the carbon dioxide removal structures between each of the stations of the first additional station, the at least one additional station, and the regeneration box, wherein the first gas has a concentration of CO.sub.2 that is higher than the concentration CO.sub.2 in the second gas.

22. The system of claim 21, wherein the carbon dioxide removal structures form a continuous loop.

23. The system of claim 21, wherein the first gas containing CO.sub.2 is ambient air.

24. The system of claim 21, wherein the second gas containing CO.sub.2 is flue gas or a mixture of flue gas and ambient air.

25. The system of claim 21, wherein the system for moving the carbon dioxide removal structures includes a track that is open-ended.

26. The system of claim 21, wherein the system for moving the carbon dioxide removal structures includes a track that is closed.

27. The system of claim 21, wherein the total number of stations for removing CO.sub.2 from either the first gas or the second gas being directly determined by the ratio of the adsorption time (for removing CO.sub.2 from the gas) to the regeneration time (for stripping CO.sub.2 from the sorbent on the porous substrate), the adsorption time being the time to adsorb, on the sorbent, CO.sub.2 from the gas mixtures from a base level to a desired level on the sorbent, and the regeneration time being the time to strip the CO.sub.2 from the desired level back to the base level on the sorbent.

28. The system of claim 21, wherein the carbon dioxide removal structures contain honeycomb monolith structures coated with an amine sorbent.

29. The system of claim 12, wherein the group of carbon dioxide removal structures include 10 carbon dioxide removal structures.

30. The system of claim 29, wherein the first set of stations includes 8 stations, wherein the at least one additional station includes 1 station.

31. A method for removing CO.sub.2 comprising: moving a group of carbon dioxide removal structures from station to station while being exposed to a first gas in a first set of stations and subsequently exposing each carbon dioxide removal structure in turn to a second gas, wherein the second gas has a concentration of CO.sub.2 that is higher than the concentration of CO.sub.2 in the first gas, wherein each removal structure comprises a porous solid substrate supported on the structure, wherein each porous substrate having a sorbent supported within its pores, wherein the sorbent being capable of adsorbing or binding to carbon dioxide; and sealably, after exposure to the second gas, placing each of the carbon dioxide removal structures in a successive manner into a regeneration box so that the carbon dioxide removal structure within the regeneration box is not exposed to the first gas or the second gas, wherein carbon dioxide sorbed upon the sorbent of the carbon dioxide removal structure is stripped from the sorbent and captured, and the sorbent regenerated during a regeneration time in the regeneration box.

32. The method of claim 31, wherein in the regeneration box the sorbent is exposed to process heat at a temperature of less than 130° C. during the regeneration time to strip the CO.sub.2 from the sorbent.

33. The method of claim 32, further comprising reducing the atmospheric pressure within the regeneration box after the carbon dioxide removal structure is sealed within the regeneration box.

34. The method of claim 31, wherein the carbon dioxide removal structures form a continuous loop.

35. The method of claim 31, wherein the first gas containing CO.sub.2 is ambient air, wherein the second gas containing CO.sub.2 is flue gas or a mixture of flue gas and ambient air.

36. A method for removing CO.sub.2 comprising: exposing a carbon dioxide removal structure to a first gas containing CO.sub.2 for a first exposure time wherein the carbon dioxide removal structure contains a porous solid substrate, wherein a sorbent is supported within at least a portion of the porous of the porous solid substate, wherein during the first exposure time the carbon dioxide removal structures is loaded with CO.sub.2 to a first loading of CO.sub.2 on the sorbent; exposing, subsequently, the carbon dioxide removal structures to a second gas containing CO.sub.2 for a second exposure time, wherein during the second exposure time the carbon dioxide removal structure is loaded with a second loading of CO.sub.2 on the sorbent, wherein the first loading of CO.sub.2 is less than the second loading of CO.sub.2; regenerating the carbon dioxide removal structure to remove at least a portion of the adsorbed CO.sub.2 on the sorbent ; and continuously removing CO.sub.2 from both from the first gas and the second gas using a group of carbon dioxide removal structures.

37. The method of claim 36, wherein the first gas containing CO.sub.2 is ambient air, wherein the second gas containing CO.sub.2 is flue gas or a mixture of flue gas and ambient air.

38. The method of claim 36, wherein the group carbon dioxide removal structures form a continuous loop.

39. The method of claim 36, wherein the group of carbon dioxide removal structures include 10 carbon dioxide removal structures.

40. The method of claim 36, wherein the carbon dioxide removal structures contain honeycomb monolith structures coated with an amine sorbent.

Description

BRIEF DESCRIPTION OF THE FIGURES AND EXHIBITS

[0089] FIG. 1 is a diagrammatic top view of a mutually interactive pair of rotating multi-capture structures systems for removing carbon dioxide from the atmosphere according to an exemplary embodiment of this invention, showing a grade level regeneration chamber for each loop and group of capture structures, and the two capture structures immediately upstream from each of the regeneration chambers are shown within sealable housings provided with sealable conduits for feeding cleaned flue gas to the capture structures;

[0090] FIG. 2 is a schematic illustration of the pair of regenerating chambers for removing carbon dioxide from the capture structures of FIG. 1, showing the several inlet and outlet conduits connected to one of the chambers and the sealable connecting conduit connecting the two chambers;

[0091] FIG. 3 is a schematic view of the regeneration chambers and flue gas capture structures on each of the adjacent loops showing a piping system arrangement for each chamber and between the chambers;

[0092] FIG. 4 is a schematic elevation view showing fans which are relatively stationary and which rotate with each capture structures, respectively;

[0093] FIG. 5 is a diagrammatic side elevation view of a Design for Dual Induced Axial Fans and Plenums of FIG. 4;

[0094] FIG. 6 is a diagrammatic elevation view of one of the mutually interactive pairs of rotating multi-capture structures system, showing the track level regeneration chamber for removing carbon dioxide from the atmosphere, and the immediately preceding two capture structure housings for treating a flue gas stream for CO.sub.2 capture;

[0095] FIG. 7 is a conceptual diagram showing the general operation of this system between the last adsorption stage and the CO.sub.2 Desorption and Regeneration Step, showing a system where the adsorption stages all treat ambient air;

[0096] FIG. 8 is a conceptual diagram showing the general operation of one of the preferred embodiments of the invention of this system, between the last adsorption-flue gas stage and the CO.sub.2 Desorption and Regeneration Step, in this embodiment the last adsorption stage, e.g., the ninth stage, immediately upstream from the “desorption unit” receives flue gas, either pure or mixed with ambient air, and the next preceding stage, e.g., the eighth stage, can receive the exhaust from the ninth stage, a mixture of that exhaust and ambient air, or only ambient air, depending upon the composition of the ninth stage exhaust;

[0097] FIG. 9 is a conceptual diagram showing the general operation of another preferred embodiment of the invention of this system, between the last adsorption-mixed air-flue gas stage and the CO.sub.2 Desorption and Regeneration Step, in this embodiment the last adsorption stage, e.g., the ninth stage, immediately upstream from the “desorption unit” receives flue gas, either mixed with ambient air; and

[0098] FIG. 10 depicts one example of the seals which extend around all sides of each capture unit in the desorption unit or in one of the flue gas adsorption units housing, when each of the housings is on the grade level and the capture structures enter each housing as each capture structure moves along the track.

MORE DETAILED DESCRIPTION OF THIS EMBODIMENT OF THE PRESENT INVENTION

[0099] A simplified depiction of the design for a system to perform these operations described above, is shown in FIGS. 1 through 6. A detailed discussion of the operation and the ancillary equipment that will be required is set out below and is similar to that shown in commonly owned U.S. Pat. Nos. 10,413,866 and 10,512,880.

[0100] In this embodiment, there are ten “capture structures,” preferably but not necessarily, located in a decagon arrangement and which are located on a substantially circular or arcuate track. There are two substantially circular (or ovoidal)/decagon assemblies associated with each process unit and they interact with each other as shown. In this preferred embodiment, air is passed through the capture structures by induced draft fans located on the inner sides of the capture structures. At one location the capture structures are in a position adjacent to a single sealable chamber box, into which each capture structure is inserted, as it moves along the track, for processing. In the sealable regeneration chamber box they are heated to a temperature of not greater than 130° C., and more preferably not above 120° C., and optimally not greater than 100° C., preferably with process heat steam to release the CO.sub.2 from the sorbent and to regenerate the sorbent. Alternatively, the regeneration chamber can be above or below grade. In this embodiment, the adsorption time for adsorbing CO.sub.2 by the capture structures is preferably ten times as long as the sorbent regeneration time.

[0101] It should be understood that although the use of porous monolithic substrates in the capture structures is preferred, if feasible one may use stationary beds of porous particulate, or granular, material supported within a frame on the capture structures. In either case, the porous substrate preferably supports an amine sorbent for CO.sub.2, when the particle capture structure has the same pore volume as the monolith capture structures for supporting the adsorbent.

[0102] The schematic drawings depict in a diagrammatic form a basic operational concept of the system according to the present invention. There are ten “capture structures” 21, 22 located in each decagon assembly arrangement and which are movably supported on a circular track 31, 33. There are two circular/decagon assemblies, A, B, associated with each process unit and they interact with each other. Air or flue gas is passed through each of the capture structures 21, 22 by induced draft fans 23, 26, located radially interiorly of each of the decagon assemblies, and inducing a flow of exhausted gas out of the inner circumferential surface of each capture structures , and up away from the system. At one location along the track 31, 33, the capture structures 21, 22 are adjacent to a sealable regeneration box 25, 27 into which the capture structures 22, 22 are inserted for regeneration processing after having completed one rotation around the track.

[0103] Thus, as shown in FIGS. 1 and 2, a first capture structure 21 is rotated into position within the regeneration box 25 for processing; for the on grade regeneration box 25. When a capture structure is in position within the regeneration box 25, movement along the track is halted for all of the capture structures. Alternatively, by increasing the diameter of the track, and the capture structure, a constant motion is made possible by having suitable sealing systems on the regeneration box, and on any flue gas adsorption housings (121, 221, 122, 222). When a capture structure 21,22 has been regenerated, as all of the capture structures move, the regenerated capture structure is moved out of the regeneration box 25, 27, so that the next capture structure 21, 22 can be moved in after having treated the flue gas, as shown in FIG. 1. This process is repeated substantially continually. In the preferred embodiment shown in the drawings, one or more of the capture structures on each track will move out of the flue gas adsorption housings (121, 221, 122, 222), as the timing is preferably matched to the timing of the flue gas desorption. Alternatively, the capture structures motion can be halted each time a capture structure enters a regeneration box and one or more flue gas adsorption housings (121, 221, 122, 222), and the motion is then restarted when the desorption and flue gas adsorption are completed.

[0104] As explained above, the present process invention, however, is a low temperature (preferably ambient-to-100° C.), semi-continuous process, with one-directional mass transport at each phase of the process. A further novel aspect of this process is that the reaction capturing the CO.sub.2 from the gas mixture preferably occurs with a regenerable material (in one preferred embodiment on an aminopolymer), the regenerable material, e.g., an aminopolymer sorbent, being impregnated within the porous substrate.

[0105] The sorbent-supporting capture structures include in preferred embodiments, monolithic substrates supported in turn by a framework to form each capture structure.

[0106] The two decagon ring assemblies operate together, although the capture structures for each decagon ring are moved in and out of their desorption./regeneration boxes at slightly different times, as explained below, to allow for the passage of heat, e.g., between box 25 and box 27, when regeneration in box 25, for example, is completed to provide for preheating of the other box, e.g. regeneration box 27. This saves heat at the beginning of the regeneration and reduces cost of cooling the capture structure after regeneration.

[0107] Three locations for the regeneration boxes 25, 27 are available, i.e., above or below the rotating capture structures, which do not permit continuous motion, or at grade level. See U.S. Pat. Nos. 10,413,866 and 10,512,880.

[0108] The regeneration chambers 321, 327 are located on grade with the rotating capture structure assemblies. The boxes are located with adequate access for maintenance and process piping also on grade. Suitable mutually sealing surfaces are located on the box and on each capture structure, so that as the capture structure moves into position in the box, the box 322, 327 is sealed, regardless of whether the motion is upward, into an elevated regeneration box, downward into a sub-grade regeneration box, or straight ahead for an on-grade regeneration box; the same is true for the embodiments where the flue gas adsorption housings (121, 221, 122, 222) can be on grade or below or above grade. There are also optional closed chambers for the immediately preceding positions along the track for the feeding of flue gas or partially cleaned flue gas into the capture structures.

[0109] In all cases ancillary equipment (such as pumps, control systems, etc.) are preferably located at grade within, or outside of the circumference of the track supporting the rotating capture structure assemblies 29.

[0110] The regeneration boxes and housings can be located at different levels, in particular situations without departing from the concept or scope of this invention.

[0111] An alternative design coming within the scope of the present invention provides for a system where the pair of regeneration boxes, chambers 25, can move along the track. This would be best used where the track design allows for reciprocating movement by the capture structures along a straight track, so that the regeneration boxes 25 would not become widely separated. Compared to prior disclosed apparatus in the prior art, this would: [0112] Minimize structural steel; [0113] Place all major equipment at grade level apart from the regeneration boxes which are only acting as containment vessels; [0114] Ensure that there is no interference with air flow to the capture structures, where the boxes are at different levels from the track; [0115] Avoid movement of the larger multi-unit system of rotating all of the capture structures to move them into a regeneration box; [0116] Allow the two regeneration boxes to be adjacent to each other with minimum clearance to permit the heat exchange desirable for increased efficiency.

[0117] The mechanical operations, with necessary machinery and power, that are required include: [0118] Rotation of the two sets of capture structure assemblies around a substantially circular track on a support structure, precisely locating elements to a position where the capture structures are to be stopped, so as to ensure the free movement of the capture structures into and out of the regeneration box and any flue gas adsorption housings. [0119] Removal of the capture structure, or the substrate only, insertion of the capture structure into the regeneration box, removal of the capture structure from the regeneration box and re-insertion of the capture structure into its position on the track assembly. All of these movements occurring in a vertical direction, or alternatively as part of the horizontal rotational movement on the track. The capture structures and regeneration boxes are designed so that, for vertically movable capture structures there is a substantially air-tight seal between the top or bottom of each of the capture structures and the support structure of the box. For on grade such regeneration boxes or flue gas adsorption housings, the seals can be on the side surfaces as well as the top and bottom surfaces, or there could be sealing doors that shut when a capture structure moves into the regeneration box or flue gas adsorption housings. Examples of some conceptual designs for such seals are shown in previously issued U.S. Eisenberger patents and by FIG. 10 of this application.

[0120] In all cases of one preferred embodiment, referring to FIGS. 1-9, a capture structure 21-1 (ring A) is rotated into position and then moved into the regeneration, or desorption, box 25 for processing. The pressure in desorption box 25 (containing capture structure 21-1, ring A) is reduced using, e.g., a vacuum pump 230, to less than 0.2 Bar. The box 25 is heated with steam at atmospheric pressure through line 235 and CO.sub.2 is generated from capture structure 21-1 and removed through the outlet piping 237 from the box 25 for the CO.sub.2 and condensate which is separated on a condenser 240 (FIG. SA). Capture structure 22-1 (ring B) is then placed in box 27 (ring B) while box 25 is being processed, as above (FIG. 5B). The steam supply to box 25 is stopped and the outlet piping for the CO.sub.2 and condensate isolated. Box 25 and box 27 are connected by opening valve 126 in connecting piping 125 (FIG. SC).

[0121] The pressure in box 27 is lowered using a vacuum pump 330 associated with box 27. This lowers the system pressure in both boxes and draws the steam and inert elements remaining in box 25 through box 27 and then to the vacuum pump. This cools box 25 (and thus capture structure 21-1, ring A) to a lower temperature (i.e. the saturation temperature at the partial pressure of the steam in the box) and reduces the potential for oxygen deactivation of the sorbent when the capture structure 21-1 is placed back into the air stream. This process also pre-heats box 27 (and thus capture structure 22-1, ring B) from ambient temperature up to the saturation temperature at the partial pressure of the steam in the box 250. Thus, energy has been recovered and the amount of atmospheric pressure steam required to heat the second box 27 (and capture structure 22-1 ring B) is reduced (FIG. SD). As the vacuum pump 330 lowers pressure in the boxes 25 and 27, the first box 25 is reduced in temperature (from 100° C. approx. to some intermediate temperature) and the second box 27 is increased in temperature (from ambient to the same intermediate temperature). CO.sub.2 and inert gases are removed from the system by the vacuum pump 330.

[0122] The valve between the first box 25 and the second box 27 is closed and the boxes isolated from each other. Capture structure 21-1 ring A is now cooled below the temperature where oxygen deactivation of the sorbent is of concern when the capture structure is placed back in the air stream. The second box 27 and capture structure 22-1, ring B, have been preheated and thus the amount of steam required for heating the box and capture structure is reduced (FIG. 5E). Capture structure 21-1 ring A is then moved out into the capture structure assembly. The ring A capture structure assembly is rotated by one capture structure and capture structure 21-2 ring A is then inserted into box 25, where it is ready for preheating. Box 27 is heated with atmospheric steam and the stripped CO.sub.2 is collected (FIG. 5F).

[0123] When the second box 27 (containing capture structure 22-1 ring B) has been fully regenerated the steam supply to box B is isolated, and the piping for the CO.sub.2 and condensate is isolated using valves 241, 242. The valving 126 between the first box 25 and the second box 27 is opened and the pressure in the boxes 25, 27 is reduced using the vacuum pump 230 system for box 25. The temperature of the second box 27 (and thus capture structure 22-1, ring B) is reduced (see 5 above). The temperature of the first box 25 (containing capture structure 21-2, ring A) is increased (see 5 above) (FIG. 5G). The vacuum pump 230 lowers pressure in boxes 25, 27. Box 25 is reduced in temperature (from 100° C. approx. to some intermediate temperature). Box 27 is increased in temperature. (from ambient to the same intermediate temperature). CO.sub.2 and inert gasses are removed from the system by the vacuum pump 230. Capture structure 22-1, ring B, is moved back into the ring assembly and the assembly rotated one bed. Capture structure 22-2, ring B, is then inserted into box 27. Box 25 (containing capture structure 21-2 ring A) is heated with atmospheric steam to release the CO.sub.2 and regenerate the sorbent (FIG. 5H) The pre-heating of box 27 then occurs as described above. The process is repeated for all of the beds as the Decagons are rotated many times.

[0124] When dealing with a preferred embodiment as depicted in FIG. 8, wherein both rings include a pair of flue gas adsorption housings immediately preceding the entry into the regeneration box, the feed of a preferably pre-treated flue gas is provided. The e.g., ninth adsorption stage immediately preceding the regeneration box, is fed with either a pre-treated flue gas having usually about 10-15% CO.sub.2, or a mixture of the pre-treated flue gas with ambient air. The exhaust from that stage can contain, e.g., from 2to 8% CO.sub.2. Preferably, when the upper range of CO.sub.2 is exhausted, the exhaust gas is most preferably passed into the immediately preceding desorption stage housing for further adsorption to reduce the exhaust gas to a suitable degree to be exhausted to the atmosphere.

PREFERRED DESIGN PARAMETERS

[0125] The current preferred basis for the design of the system is as follows: [0126] Weight of individual capture structures to be moved: [0127] 1,500-10,000 lbs. (including support structure) [0128] Approximate size of bed: Width-5-6 meters [0129] Height-9-10 meters [0130] Depth-0.15-1 meter

[0131] It should be noted that the capture structure dimensions could be adjusted depending upon the particular conditions at the geographic location of each pair of systems, and the desired, or attainable, processing parameters.

[0132] For a system including 10 capture structures in each of the Decagon rings, the outer dimensions of a preferred circular/decagon structure would be about 15-17 meters, preferably about 16.5 meters. The capture structures support structures may be individually driven, for example by an electric motor and drive wheel along the track, or the support structures could be secured to a specific location along the track and a single large motor used to drive the track and all of the structures around the closed loop. In either case, the regeneration box is placed at one location and all of the structures can stop their movement when one of the support structures is so placed as to be moved into the regeneration box. The economics of a single drive motor or engine, or multiple-drive motors or engines, will depend on many factors, such as location and whether the driving will be accomplished by an electrical motor or by some fuel-driven engine. The nature of the driving units is not, itself, a primary feature of this invention, and many are well-known to persons skilled in the art. Examples of suitable engines include internal or external combustion engines or gas pressure driven engines, for example operating using the Stirling engine cycle, or process steam engines or hydraulic or pneumatic engines.

[0133] When a regeneration box is located above the track level, the top will be about 20 meters above the grade of the track, and when the regeneration box is located below the grade of the track, the top of the box will be immediately below the track grade. A box on grade will only be minimally above the tops of the capture structures, so as to accommodate the capture structures wholly within the box during regeneration.

[0134] Where the regeneration box is not on grade, the elevator system for moving the capture structures into and out of the regeneration box should be able to accomplish the movement into and out of the box during a period within the range of 30 seconds to i20 seconds, and preferably between 30 and 45 seconds. The shorter the time period, the greater the flexibility in the process parameters that are available for the process. It is recognized that there are certain inherent mechanical limitations in moving the massive capture structures.

[0135] One advantage where the regeneration box is on grade, is that vertical movement is not needed, as the capture structures merely rotates into the box, as part of its rotational movement, and seals; thus avoiding the vertical movement, the loss of time and the additional capital cost of the elevators. In each case, the two edges of the capture structure are solid and form seals with the edges of the regeneration box.