Apparatus and process for temperature swing adsorption with resistive heating

Abstract

Apparatuses and methods of removing or separating CO2 from a process gas by temperature swing absorption with resistive heating utilizing at least one cycle of steps such as adsorbing CO2 gas from the process gas and holding the adsorbed CO2 gas with a sorbent bed, and heating the sorbent bed with one or more electrodes to release at least some of the adsorbed CO2 gas from the sorbent bed, wherein the heating step occurs after the absorbing step, and wherein the one or more electrodes are removably in contact with the sorbent bed during the heating step.

Description

APPARATUS AND PROCESS FOR TEMPERATURE SWING ADSORPTION WITH RESISTIVE HEATINGCross Reference to Related Application

[0001] This application claims the benefit of priority under 35 U.S.C. §119 of U.S. Provisional Application Serial No. 63 / 536824 filed on September 6, 2023, the content of which is relied upon and incorporated herein by reference in its entirety.TECHNICAL FIELD

[0002] Embodiments of the present disclosure generally relate to articles and methods for removing carbon dioxide from the process gas via a temperature swing adsorption with resistive heating.BACKGROUND

[0003] Carbon dioxide (CO2) capture and removal by adsorption processes is one of the technological solutions to address the current global climate challenge. More robust and safer electrode contact with a sorbent that such as a ceramic honeycomb structure is not yet available.SUMMARY

[0004] In one or more aspects, apparatuses and are methods are disclosed herein for removing, or separating, carbon dioxide gas (“gaseous carbon dioxide”, or “gaseous CO2”, or “CO2”) from a gas volume or gas stream, herein referred to as process gas, which contains CCL-ladcn process gas.

[0005] In one or more aspects, apparatuses and methods are disclosed herein of removing (or separating) CO2 from a process gas (or CCL-laden process gas). Methods disclosed herein comprise at least one cycle comprising the steps of: adsorbing CO2 gas from the process gas and holding the adsorbed CO2 gas with a sorbent bed, and heating the sorbent bed with one or more electrodes to release at least some of the adsorbed CO2 gas from the sorbent bed, wherein the heating step occurs after the absorbing step, and wherein the one or more electrodes are removably in contact with the sorbent bed during the heating step.

[0006] In one or more other aspects, apparatuses and methods are disclosed herein of removing (or separating) CO2 from a process gas (or CCf-ladcn process gas), the method comprising at least one cycle comprising the steps of: adsorbing CO2 gas from the process gas and holding the adsorbed CO2 gas with a sorbent bed, and heating the sorbent bed with one or more electrodes to release at least some of the adsorbed CO2 gas from the sorbent bed, wherein the heating step occurs after the absorbing step, and wherein essentially no process gas flows into, or out of, or neither into nor out of, the sorbent bed.

[0007] In one or more other aspects, apparatuses and methods are disclosed herein of removing (or separating) CO2 from a process gas such as a CCh-laden process gas, the method comprising at least one cycle comprising the steps of: adsorbing CO2 gas from the process gas and holding the adsorbed CO2 gas with a sorbent bed; and heating the sorbent bed with one or more electrodes to release at least some of the adsorbed CO2 gas from the sorbent bed; wherein the heating step occurs after the absorbing step; and wherein the one or more electrodes are removably in contact with the sorbent bed during the heating step.

[0008] This aspect may further comprise, after the adsorbing step and before the heating step, a step of evacuating (or removing) at least a portion of any gaseous species (which may include gas phase of any liquid present in the container) which may be present inside the container, which may include inside the adsorbent bed or adsorbent material.

[0009] In this aspect, an additional step of cooling the sorbent material is performed, after the heating step and preferably after the purging step if carried out, wherein the step of cooling comprises cooling the sorbent material with a cooling gas stream which is preferably free or essentially free of any oxygen gas species. In embodiments, the cooling gas stream comprises nitrogen. In embodiments, the cooling gas stream comprises water vapor or steam. In embodiments, the cooling gas stream comprises water vapor. In embodiments, \the cooling gas stream comprises steam. In embodiments, the cooling gas stream comprises nitrogen, water vapor, or steam, or combinations thereof.

[0010] In another aspect, an apparatus for removing gaseous carbon dioxide from a process gas is disclosed herein, the apparatus comprising: a housing comprising one or more walls having one or more inner surfaces defining an interior cavity, the one or more walls comprise a one or more openings; a sorbent bed disposed within the housing, the sorbent bed occupying a sorbent bed volume within the interior cavity; and at least one electrode configured to intermittently contact the sorbent bed.BRIEF DESCRIPTION OF THE DRAWINGS

[0011] FIGS. 1A-1C schematically illustrate the above three process steps as disclosed herein: FIG. 1A adsorption, FIG. IB heating, FIG. 1C purging.

[0012] FIGS. 2A-2D schematically illustrate an aspect disclosed herein, similar to the aspect illustrated in FIGS. 1A-1C and further comprising a step of evacuating the sorbent bed volume (FIG. 2B).

[0013] FIGS. 3A-3E schematically illustrate an aspect disclosed herein, similar to the aspect illustrated in FIGS. 2A-2D with similar reference numerals, and which further comprises a step of cooling the sorbent bed (FIG. 3E).

[0014] FIGS. 4A-4B schematically illustrate an absorbent bed, or sorbent bed, having a rectangular shaped bed. FIG. 4A shows a cutaway side view showing the flow direction of the gases. FIG. 4B shows a cutaway top view of the sorbent bed. FIG. 4A shows a cross sectional view showing honeycomb cell walls and the associated axial channels which allow gas to pass through the honeycomb structure in either direction. FIG. 4B shows intersecting walls of the honeycomb structure which define the channels.

[0015] FIG. 5A schematically illustrates the configuration of a sorption unit during the heating step with electrodes applied to, and in contact with, the inlet and outlet faces of the sorbent bed.

[0016] FIG. 5B schematically illustrates the configuration of a sorption unit during the steps other than the heating step, where the electrodes have been moved away, and are spaced away, from the sorbent bed, in which configuration gas flow may pass into and out of the sorbent bed.

[0017] FIG. 6 schematically illustrates, in another aspect, a side cutaway view of an adsorbent apparatus 100 wherein one or more electrodes 50 are applied to only one side of the sorbent bed 20.

[0018] FIGS. 7A-7B schematically illustrate an exemplary electrode. FIG. 7A shows a side cutaway view of a sorbent bed, wherein electrodes are shown in contact with opposite sides of the sorbent bed, wherein the electrodes can be moved in and out of contact via motive devices. FIG. 7A shows a delineation of the area of the detail shown in FIG. 7B.

[0019] FIG. 8 schematically illustrates a test setup used for assessing electrode materials for use as disclosed herein.

[0020] FIG. 9 shows a list of various electrode materials evaluated in samples according to the test setup of FIG. 8.

[0021] FIG. 10 shows photographic images of the samples of the various electrode materials of FIG. 9.

[0022] FIG. 11 graphically illustrates normalized temperature results versus time, defined as, 0 = (T — T0) / (Tfin— To) wherein T is temperature of the honeycomb, Tois initial temperature, and Tfinis final temperature, for testing of an electrically conductive sorbent bed using a setup as in FIG. 8.

[0023] FIG. 12 graphically illustrates the temperature inside an electrically conductive honeycomb sorbent bed as in FIG. 11 for various applied electrical power values.DETAILED DESCRIPTION

[0024] Before describing several exemplary embodiments of the disclosure, it is to be understood that the disclosure is not limited to the details of construction or process steps set forth in the following description. The disclosure is capable of other embodiments and of being practiced or being carried out in various ways.

[0025] A more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings, in order to help understand the above recited features of the present disclosure in detail. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this disclosure and are therefore not to be considered limiting of its scope, for the disclosure may admit to other equally effective embodiments.

[0026] Methods disclosed herein comprise at least one cycle comprising the steps of: adsorbing CO2 gas from the process gas and holding the adsorbed CO2 gas with a sorbent bed, and heating the sorbent bed with one or more electrodes to release at least some of the adsorbed CO2 gas from the sorbent bed, wherein the heating step occurs after the absorbing step, and wherein the one or more electrodes are removably in contact with the sorbent bed during the heating step.

[0027] In embodiments, the one or more electrodes are in contact with the sorbent bed only during the heating step.

[0028] In embodiments, the one or more electrodes are removed from contact with the sorbent bed in one or more steps other than the heating step.

[0029] In embodiments, the one or more electrodes are removed from contact with the sorbent bed in every step other than the heating step.

[0030] In embodiments, the one or more electrodes prevent gas flow into or out of the sorbent bed during the heating step.

[0031] In embodiments, the one or more electrodes prevent gas flow into and out of the sorbent bed during the heating step.

[0032] In embodiments, the sorbent bed is disposed within a sorbent bed volume within a housing, and the sorbent bed volume is essentially gas tight during the heating step.

[0033] In embodiments, the process gas flows into the sorbent bed during the absorption step.

[0034] In embodiments, the sorbent bed volume is gas purged during a purging step after the heating step.

[0035] In embodiments, at least a portion of the CO2 in the CO2 laden process gas is removed from the process gas and held by the sorbent bed, wherein the sorbent bed is disposed within a sorbent bed volume defined by a housing (or container) n which the sorbent bed resides, and the heating step comprises heating the sorbent bed to desorb (or release) at least a portion of the CO2 from the sorbent bed (“desorbed CO2”), wherein essentially no gas escapes from the sorbent bed volume, wherein the heating comprises applying an electric potential to the sorbent bed, and then the desorbed CO2 is purged from the sorbent bed volume.

[0036] In one or more other aspects, apparatuses and methods are disclosed herein of removing (or separating) CO2 from a process gas (or CCh-laden process gas), the method comprising at least one cycle comprising the steps of: adsorbing CO2 gas from the process gas and holding the adsorbed CO2 gas with a sorbent bed, and heating the sorbent bed with one or more electrodes to release at least some of the adsorbed CO2 gas from the sorbent bed, wherein the heating step occurs after the absorbing step, and wherein essentially no process gas flows into, or out of, or neither into nor out of, the sorbent bed.

[0037] In one or more other aspects, apparatuses and methods are disclosed herein of removing (or separating) CO2 from a process gas such as a CC -laden process gas, the method comprising at least one cycle comprising the steps of: adsorbing CO2 gas from the process gas and holding the adsorbed CO2 gas with a sorbent bed; and heating the sorbent bed with one or more electrodes to release at least some of the adsorbed CO2 gas from the sorbent bed; wherein theheating step occurs after the absorbing step; and wherein the one or more electrodes are removably in contact with the sorbent bed during the heating step.

[0038] In embodiments, the one or more electrodes are in contact with the sorbent bed only during the heating step.

[0039] In embodiments, the one or more electrodes are removed from contact with the sorbent bed in one or more steps other than the heating step.

[0040] In embodiments, the one or more electrodes are removed from contact with the sorbent bed in every step other than the heating step.

[0041] In embodiments, the one or more electrodes prevent gas flow into or out of the sorbent bed during the heating step.

[0042] In embodiments, the one or more electrodes prevent gas flow into and out of the sorbent bed during the heating step.

[0043] In embodiments, the sorbent bed is disposed within a sorbent bed volume within a housing, and the sorbent bed volume is essentially gas tight during the heating step.

[0044] In embodiments, the process gas flows into the sorbent bed during the absorption step.

[0045] In embodiments, the sorbent bed volume is gas purged during a purging step after the heating step.

[0046] In embodiments, at least a portion of the CO2 in the process gas is removed from the process gas and held by the sorbent bed, wherein the sorbent bed is disposed in a sorbent bed volume defined by a housing (or container) in which the sorbent bed resides, and the heating step comprises desorbing (or releasing) at least a portion of the CO2 from the sorbent bed (“desorbed CO2”), wherein essentially no gas escapes from the sorbent bed volume, wherein the heating comprises applying an electric potential to the sorbent bed, and then the desorbed CO2 is purged from the sorbent bed volume.

[0047] In one or more other aspects, apparatuses and methods are disclosed herein of removing (or separating) CO2 from a process gas (such as a CCh-laden) process gas, the method comprising at least one cycle comprising the steps of: adsorbing CO2 by exposing the process gas to a sorbent bed, wherein at least a portion of the CO2 in the process gas is removed from the process gas and held by the sorbent bed , wherein the sorbent bed is disposed in a sorbent bed volume defined by a housing (or container) in which the sorbent bed resides; heating the sorbent bed to desorb (or release) at least a portion of the CO2 from the sorbent bed (“desorbed CO2”), wherein essentially no gas escapes from the sorbent bed volume, wherein the heatingcomprises applying an electric potential to the sorbent bed; and purging the desorbed CO2 from the sorbent bed volume.

[0048] In embodiments, during the heating step, essentially no gas enters the sorbent bed volume.

[0049] In embodiments, no gas escapes from the container during the heating step.

[0050] In embodiments, the purging comprises introducing a fluid medium into the sorbent bed volume to create a desorb fluid comprising the desorbed CO2. In some embodiments, the fluid medium comprises water vapor or steam or both. In some embodiments, CO2 is separated from the desorb fluid via condensation, for example of the water vapor, or the steam, or both.

[0051] In embodiments, the applying the electric potential comprises contacting the sorbent bed with one or more electrodes. In some embodiments, at least one of the one or more electrodes comprises an electrically conductive contact element for contacting the sorbent bed; in some of these embodiments, the electrically conductive contact element comprises graphite, wire mesh, or combinations thereof; in some embodiments, the electrically conductive contact element is connected to one pole of an electric power supply; in some of these embodiments, the electrode further comprises an support element for supporting the electrically conductive contact element; in some of these embodiments, the support element is electrically insulating; in some of these embodiments, the electrode further comprises an electrically insulating of element disposed between the support element and the electrically conductive contact element.

[0052] In some embodiments, none of the one or more electrodes is disposed inside the sorbent bed.

[0053] In some embodiments, during the heating step, no convective heat losses occur from the sorbent bed volume.

[0054] In some embodiments, during the heating step, the one or more electrodes prevent flow into and out of the sorbent bed volume. In some of these embodiments, during the adsorbing step, the one or more electrodes do not prevent flow into and out of the sorbent bed volume. In some of these embodiments, during the purging step, the one or more electrodes do not prevent flow into and out of the sorbent bed volume.

[0055] In some embodiments, during the adsorbing and the purging, the one or more electrodes do not prevent flow into and out of the sorbent bed volume.

[0056] In some embodiments, the one or more electrodes are brought into, and out of, contact with the sorbent bed by one or more actuators. In some of these embodiments, at least one ofthe one or more actuators is driven pneumatically. In some of these embodiments, at least one of the one or more actuators is driven hydraulically. In some of these embodiments, at least one of the one or more actuators is driven by an electric motor.

[0057] In some embodiments, during the adsorbing, the one or more electrodes do not contact the sorbent bed.

[0058] In some embodiments, during the purging, the one or more electrodes do not contact the sorbent bed.

[0059] In some embodiments, during the adsorbing and the purging, the one or more electrodes do not contact the sorbent bed.

[0060] In some embodiments, during the adsorbing step the CCh-ladcn process gas enters the container and contacts an inlet surface of the sorbent bed, and passes over or through the sorbent bed, and during the heating step at least one of the electrodes covers at least a portion of the inlet surface thereby preventing essentially all gas flow to the sorbent bed. In some of the embodiments, the inlet surface is completely covered by one or more of the electrodes. In some of the embodiments, during the heating step, no electrodes cover the outlet surface. In some of the embodiments, during the heating step, at least one of the electrodes covers at least a portion of the outlet surface.

[0061] In some embodiments, during the adsorbing step the CCh-ladcn process gas enters the container and contacts an inlet surface of the sorbent bed, and passes over or through the sorbent bed, and during the heating step at least one of the electrodes covers at least a portion of the inlet surface thereby preventing essentially all gas flow to the sorbent bed. In some of these embodiments, the inlet surface is completely covered by one or more of the electrodes. In some of these embodiments, during the heating step, no electrodes cover the outlet surface. In some of these embodiments, during the heating step, at least one of the electrodes covers at least a portion of the outlet surface.

[0062] In some embodiments, during the adsorbing step the process gas exits the container from an outlet surface of the sorbent bed, wherein the adsorbed CO2 remains in the sorbent bed, and during the heating step at least one of the electrodes covers at least a portion of the outlet surface thereby preventing essentially all gas flow from the sorbent bed. In some of these embodiments, the outlet surface is completely covered by one or more of the electrodes; in some of these embodiments, during the heating step, no electrodes cover the inlet surface;in other embodiments, during the heating step, at least one of the electrodes covers at least a portion of the inlet surface.

[0063] In some embodiments, during the adsorbing step the process gas enters the container and contacts an inlet surface of the sorbent bed, and passes over or through the sorbent bed, and during the heating step at least one of the electrodes covers the inlet surface thereby preventing essentially all gas flow to the sorbent bed.

[0064] In some embodiments, during the adsorbing step the process gas exits the container from an outlet surface of the sorbent bed, wherein the adsorbed CO2 remains in the sorbent bed, and during the heating step at least one of the electrodes covers the outlet surface thereby preventing essentially all gas flow from the sorbent bed.

[0065] This aspect may further comprise, after the adsorbing step and before the heating step, a step of evacuating (or removing) at least a portion of any gaseous species (which may include gas phase of any liquid present in the container) which may be present inside the container, which may include inside the adsorbent bed or adsorbent material. In embodiments, the gaseous species is evacuated by applying a vacuum; in some embodiments, the vacuum is applied by a vacuum pump; in some embodiments, the vacuum is applied by exposing an interior of the container to a lower pressure which is below a pressure of any gaseous species present in the container, and / or below a pressure of the process gas; in some of these embodiments, the vacuum also causes (i.e. is sufficient to cause) one or more co-adsorbed gaseous species other than CO2 to desorb from the adsorbent material; in some of these embodiments, the vacuum also causes (i.e. is sufficient to cause) one or more co-adsorbed gaseous species other than CO2 to evacuate the container.

[0066] In some embodiments, the gaseous species is selected from the group consisting of CO2, N2 and O2.

[0067] In some embodiments, the gaseous species is selected from the group consisting of CO2, N2, O2, and combinations thereof.

[0068] In this aspect, an additional step of cooling the sorbent material is performed, after the heating step and preferably after the purging step if carried out, wherein the step of cooling comprises cooling the sorbent material with a cooling gas stream which is preferably free or essentially free of any oxygen gas species. In embodiments, the cooling gas stream comprises nitrogen. In embodiments, the cooling gas stream comprises water vapor or steam. In embodiments, the cooling gas stream comprises water vapor. In embodiments, \the coolinggas stream comprises steam. In embodiments, the cooling gas stream comprises nitrogen, water vapor, or steam, or combinations thereof.

[0069] In another aspect, an apparatus for removing gaseous carbon dioxide from a process gas is disclosed herein, the apparatus comprising: a housing comprising one or more walls having one or more inner surfaces defining an interior cavity, the one or more walls comprise a one or more openings; a sorbent bed disposed within the housing, the sorbent bed occupying a sorbent bed volume within the interior cavity; and at least one electrode configured to intermittently contact the sorbent bed.

[0070] In embodiments, the one or more walls comprise a first opening and a second opening. In embodiments, the first and second openings are disposed opposite to each other.

[0071] In embodiments, the sorbent bed comprises opposing first and second ends; in some embodiments, a first electrode is configured to intermittently contact the first end of the sorbent bed; in some of these embodiments, a second electrode is configured to intermittently contact the second end of the sorbent bed.

[0072] In embodiments, the at least one electrode is configured to form a gas tight seal on the sorbent bed when in contact with the sorbent bed.

[0073] In embodiments, the sorbent bed comprises a honeycomb structure comprised of a plurality of walls forming a plurality of channels extending from a first end of the sorbent bed to the second end of the sorbent bed.

[0074] Thus, in various aspects disclosed herein are processes, or methods, and apparatuses to remove or separate carbon dioxide (“CO2” or “CO2”) from a process gas or process gas stream using a temperature swing process (TSA), in which a temperature increase is achieved by electrically heating a sorbent material. The process gas can be ambient air or another CO2 containing process gas. A process gas with CO2 concentrations of 5% by volume or less may be particularly suitable for the temperature swing process. Thus, disclosed herein are process and operation as well as apparatus used to intermittently apply electric power or electric current to the sorbent bed during a heating phase of the desorption step. The process disclosed herein comprises the steps of: (A) adsorption of CO2 from the process gas in the adsorbent bed (or sorbent bed) ; (H) heating of the sorbent using an electric potential applied to the sorbent bed, preferably without any gas flow out of the sorbent bed during heating, and in this step electrodes are applied and connected to the sorbent bed, such the inlet face, the outlet face, or both the inlet face and the outlet face; (P) purging of the bed and desorbed CO2 present in thegas phase (such as by using a fluid medium, and preferably creating a fluid flow with high CO2 concentration, for example, which can be further purified in a downstream operation, for example). These steps may constitute a cycle and the steps may be repeated for a plurality of cycles.

[0075] In one aspect the fluid medium for the purge in the purging step can be, for example, water vapor, or steam, which can allow for a relatively simple downstream separation via condensation, leaving a more highly concentrated CO2 product outcome of the process.

[0076] FIGS. 1A-1C schematically illustrate the above three main process steps (FIG. 1A adsorption, FIG. IB heating, FIG. 1C purging) with an apparatus (or sorbent bed unit) lOOthat comprises a sorbent bed 20 disposed in a housing or container 30, wherein electrodes 50 come into contact with the sorbent bed during the heating step, and out of contact with the sorbent bed 20 during the adsorption step and the purge step as illustrated in FIGS. 1A-1C. A CO2 rich or CO2 laden process gas stream 10 enters the sorbent bed unit 100 comprised of a sorbent bed 20 and housing (or container or column vessel) 30. A CO2 lean process gas stream 40 can exit the sorbent bed unit 100 during the adsorption step. During the heating step, one or more electrodes 50 are in contact with the sorbent bed 20, and preferably electrodes 50 seal in the sorbent bed 20 such that no gas flow, or essentially no gas flow, exits the sorbent bed volume 25 (an example of which is schematically shown by dashed line in FIG. 1A for illustration purposes) in which the sorbent bed 20 is disposed, and in various embodiments no gas flow, or essentially no gas flow, exits the housing 30 either. The sorbent bed volume 25 may be larger than the sorbent bed 20 itself, thereby providing an additional gas situated outside the dimensions of the sorbent bed itself. Electrical supply lines 60 deliver electrical current to the electrode(s) from an electrical power source 70 during the heating step. During the purging step, inlet purge gas 80 enters the housing 30 and the sorbent bed 20, preferably in a direction opposite to the direction of the process stream 10 that occurred during the adsorption step. The gas inside the sorbent bed volume 25 is then preferably forced out of the sorbent bed volume, preferably at a location opposite to the inlet purge gas 80, and exits the sorbent bed volume 25 and the housing 30 as an outlet purge gas 90.

[0077] In various aspects, the process may comprise additional steps, and / or the apparatus may comprise additional components.

[0078] FIGS. 2A-2D schematically illustrate an aspect disclosed herein, similar to the aspect illustrated in FIGS. 1 A-1C with similar reference numerals, and which further comprises a stepof evacuating the sorbent bed volume per FIG. 2B. Thus, the process steps may comprise: (A) adsorption of CO2 from the process gas in the adsorbent bed (FIG. 2A); (E) evacuation of the gas phase inside the adsorbent bed using a vacuum pump 110 to a pressure below the pressure of the process gas to remove gas species which are either in the gas phase or weakly coadsorbed (e.g. primarily N2 and / or O2) (FIG. 2B); (H) heating of the sorbent using an electric potential applied to the sorbent bed without any gas flow (FIG. 2C); (P) purging the bed and desorbed CO2 which is present in the gas phase using a fluid medium, creating a fluid flow with high CO2 concentration (FIG. 2D) which can be optionally further purified in downstream operations. As in other aspects disclosed herein, only during the heating step are electrodes applied and contacting and connected to the inlet and / or outlet face of the sorbent bed (FIG. 2C). These steps may constitute a cycle and the steps may be repeated for a plurality of cycles.

[0079] FIGS. 3A-3E schematically illustrate an aspect disclosed herein, similar to the aspect illustrated in FIGS. 2A-2D with similar reference numerals, and which further comprises a step of cooling the sorbent bed per FIG. 3E, which may be advantageously utilized in conjunction with one or more amine-based sorbent materials in the sorbent bed. Thus, the process steps may further comprise, after the purging step, a cooling step comprising cooling the sorbent bed with an oxygen free gas stream, wherein inlet cooling gas 115 enters the housing 30 and the sorbent bed 20, in some embodiments in a direction opposite to the direction of the process stream 10 that occurred during the adsorption step. The gas inside the sorbent bed volume 25 cools the sorbent bed 20 and exits the sorbent bed 20, and exits the sorbent bed volume 25 and the housing 30 as an outlet cooling gas, or cooling gas outlet, 120, preferably at a location opposite to the inlet cooling gas 115.

[0080] As in all aspects disclosed herein, preferably only during the heating step are electrodes applied and contacting and connected to the inlet and / or outlet face of the sorbent bed. These steps may constitute a cycle and the steps may be repeated for a plurality of cycles. An exemplary cooling gas may comprise nitrogen, or low temperature water vapor, or even steam.

[0081] Thus, as illustrated in FIGS. 1 A-1C, 2A-2D, and 3A-3E, in various aspects, an electric potential is applied to the sorbent bed 20 only during the process step during which the adsorbent bed 20 is electrically heated. Preferably, during the heating step, no gas flow is introduced into the sorbent bed volume 25, and more preferably no gas enters or exits the sorbent bed volume 25 during the heating step. Advantageously, the electrode or electrodes 50 may cover the entire inlet area and / or the entire outlet area of the sorbent bed, thus providinggood physical and electrical contacts and distribution of the electric current, thereby providing very rapid and uniform heat up, especially when no convective heat losses occur, as well as minimizing the formation of hot spots due to poor electrode contact or non-uniform path of the electric current.

[0082] Exemplary embodiments are described below. The examples provided are not meant to be exhaustive and further variants can be envisioned.

[0083] FIGS. 4A-4B schematically illustrate an absorbent bed, or sorbent bed, having a rectangular shaped bed, although other that geometry is, such as square, round, oval, etc., Are possible. FIG. 4A shows a cutaway side view of the flow direction of the gases. FIG. 4B shows a cutaway top view of the sorbent bed. Housing or shell 30 encases the adsorber sorbent bed 20. In various aspects, gas flow may pass through the sorbent bed in either direction.

[0084] FIGS. 4A-4B schematically illustrate the configuration of the sorption unit during the steps of adsorption, evaporation, purging, and cooling. For embodiments with a sorbent bed 20 having a honeycomb structure, FIG. 4A shows a cross sectional view showing honeycomb cell walls and the associated axial channels which allow gas to pass through the honeycomb structure in either direction. FIG. 4B shows intersecting walls of the honeycomb structure which define the channels.

[0085] FIG. 5 A schematically illustrates the configuration of the sorption unit 100 during the heating step, here illustrating electrodes 50 applied to, and in contact with, the inlet and outlet faces of the sorbent bed 20. Preferably, the electrodes 50 block gas flow at the inlet and outlet faces of the sorbent bed 20. Motion device 150 provides movement of the electrode(s) 50 into and out of contact with the sorbent bed 20. In various aspects, one or more electrodes 50 also provide a pole of the applied electric potential.

[0086] FIG. 5A shows the electrodes 50 in contact with the sorbent bed 20 during the heating step.

[0087] FIG. 5B schematically illustrates the configuration of the sorption unit 100 during the steps other than the heating step, where the electrodes 50 have been moved away, and are spaced away, from the sorbent bed 20, in which configuration gas flow may pass into and out of the sorbent bed 20, as the electrodes 50 have been moved out of physical (and electrical) contact with the sorbent bed 20.

[0088] FIG. 6 schematically illustrates, in another aspect, a side cutaway view of an adsorbent apparatus 100 wherein one or more electrodes 50 are applied to only one side of the sorbentbed 20. As seen in FIG. 6, an electrode element 50 is separated into two electrodes 50 which are connected to two poles of electric potential source, and one or more motive devices 150 to provide for movement of the electrodes 50 into and out of contact with the sorbent bed 20. An electric separator 160 comprised of electrically insulative material may be disposed in the sorbent bed 20 to facilitate electric current resulting from the applied electric potential to pass through the sorbent bed 20, preferably through the entire bed 20.

[0089] FIGS. 7A-7B schematically illustrate, in another aspect, an exemplary electrode 50. FIG. 7A shows a side cutaway view of a sorbent bed 20 disposed within the housing 30, wherein the electrodes 50 are shown in contact with opposite sides of the sorbent bed 20, wherein the electrodes 50 can be moved in and out of contact via the motive devices 150. FIG. 7A shows a delineation of the area of the detail shown in FIG. 7B. The sorbent bed 20 in FIGS. 7A-7B has a honeycomb structure comprised of intersecting walls 117 which define channels longitudinal 118 that provide gas flow passages from one face of the sorbent bed to the other face.

[0090] In various aspects electrode 50 may comprise one or more conductive layers 190 comprised of low electric resistance material and preferably having good mechanical flexibility in order to help achieve a good contact with the ends of the walls 117 of the honeycomb structure or other structure of sorbent bed 20. The conductive layer 190 may be comprised of exemplary materials such as graphite, wire mesh such as metal wire mesh, or other flexible or soft material with low electrical resistance. The one or more electrically conductive layer 190 is connected to electrically conductive element 210, which is connected to one pole of an electric power supply and has low electrical resistance. In embodiments, electrically conductive element or electric conductor 210 is disposed within movement member 220 which provides for the mechanical movement and is connected to a device that enable this movement. Movement member 220 is preferably electrically insulated from the electric conductor 210. Support member 200 optionally provides for the mechanical strength of the electrode plate and has sufficient stiffness to ensure uniform pressure is applied to the adsorbent bed over the entire cross-section. Support member 200 may be mechanically connected to the conductive layer 190, and may be either made from a material with high electrical resistance, serving an electric insulator itself, or as an electrical insulation layer added between conductive layer 190 and support member 200. Support member 200 may also be mechanically connected to movement member 220.

[0091] EXAMPLES

[0092] FIG. 8 schematically illustrates a test setup used for assessing exemplary electrode materials. An electrically conductive cylindrical honeycomb sample with a diameter of 50 mm and an axial length of 150 mm was placed in between two electrodes made from the same electrode material. In each of the examples the same honeycomb sample was used. The electrodes were connected to an electric power source. To ensure sufficient contact between the electrode material and the electrically conductive honeycomb body, a force FN was applied in the axial direction. A force FN was applied at a level above which a further increase in force did not result in any change in the measured electrical resistance of the arrangement.

[0093] FIG. 9 is a list of various electrode materials evaluated in samples according to the test setup of FIG. 8.

[0094] FIG. 10 shows photographic images of the samples of the various electrode materials of FIG. 9. We observed that Sample Electrode A of conductive carbon filled rubber electrode material results in a too high resistance, which did not enable functioning of a system as disclosed herein. All the other samples of the remaining electrode materials in FIG. 9 yielded comparable composite electrical resistances with values that enabled a functioning system as disclosed herein.

[0095] For the apparatuses and methods disclosed herein, we have found that, in one aspect, the electrode material advantageously has an electrical resistance of less than 100 ohms, in some embodiments in the range of 1 ohm to 90 ohms, in some embodiments in the range of 1 ohm to 50 ohms, in some embodiments in the range of 1 ohm to 30 ohms, in some embodiments in the range of 1 ohm to 20 ohms, in some embodiments in the range of 1 ohm to 10 ohms, and in some embodiments in the range of 5 ohms to 10 ohms.

[0096] A setup analogous to that shown in FIG. 8 was used to evaluate the resistive heating of an electrically conductive honeycomb sample according to the heating step as disclosed herein, wherein an electrode of electrode material E per FIG. 9 was used. To obtain the temperature inside the honeycomb and record the heating process, three thermocouples (Type K, 0.5mm) were inserted into the center of the honeycomb, placed at different axial locations (top = 10mm from top, center = 75mm from top, bottom = 10mm from bottom). Testing was carried out by applying a specific electric power of 1.34W per mass of honeycomb per gram, i.e. 1.34W / g. Each test started at room temperature and was stopped when a temperature of 60°C was reached inside the honeycomb. Results are shown in FIG. 11, showing an increase in the normalizedtemperature, defined as, 0 = (T — T0~) / (Tfin— To) wherein T is temperature of the honeycomb, Tois initial temperature, and Tfinis final temperature. The results demonstrate that with this setup and specific power the final temperature can be reached within roughly 60s (60 seconds). The heating within the honeycomb samples was relatively uniform, wherein differences may be due to the actual placement of the thermocouple.

[0097] The same setup was used to evaluate the influence of the electric power on the heating rate. FIG. 12 graphically illustrates the temperature inside the honeycomb, averaged over the three (3) inserted thermocouples.

[0098] In aspects disclosed herein, the sorbent bed comprises an electrically conductive substrate, such as an electrically conductive honeycomb body.

[0099] In embodiments disclosed herein, during the heating step the sorbent bed reaches a temperature which is within 10% of a top target temperature in less than 800 seconds. In some embodiments disclosed herein, during the heating step the sorbent bed reaches a temperature which is within 10% of a top target temperature in less than 600 seconds. In some embodiments disclosed herein, during the heating step the sorbent bed reaches a temperature which is within 10% of a top target temperature in less than 400 seconds. In some embodiments disclosed herein, during the heating step the sorbent bed reaches a temperature which is within 10% of a top target temperature in less than 200 seconds. In some embodiments disclosed herein, during the heating step the sorbent bed reaches a temperature which is within 10% of a top target temperature in less than 100 seconds. In some embodiments disclosed herein, during the heating step the sorbent bed reaches a temperature which is within 10% of a top target temperature in less than 60 seconds. In some embodiments disclosed herein, during the heating step the sorbent bed reaches a temperature which is within 10% of a top target temperature in less than 50 seconds.

[0100] In embodiments disclosed herein, during the heating step greater than 0.05 watts per gram (W / g) of sorbent bed are applied to the sorbent bed. In some embodiments disclosed herein, during the heating step greater than 0.05 watts per gram (W / g) of sorbent bed and less than 2.0 W / g are applied to the sorbent bed. In some embodiments disclosed herein, during the heating step greater than 0.05 watts per gram (W / g) of sorbent bed and less than 1.5 W / g are applied to the sorbent bed.

[0101] Reference throughout this specification to "one embodiment," "certain embodiments," "one or more embodiments" or "an embodiment" means that a particular feature, structure, material, or characteristic described in connection with the embodiment is included in at least one embodiment of the disclosure. Thus, the appearances of the phrases such as "in one or more embodiments," "in certain embodiments," "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily referring to the same embodiment of the disclosure. Furthermore, the particular features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments.

[0102] Although the disclosure herein has been described with reference to particular embodiments, those skilled in the art will understand that the embodiments described are merely illustrative of the principles and applications of the present disclosure. It will be apparent to those skilled in the art that various modifications and variations can be made to the method and apparatus of the present disclosure without departing from the spirit and scope of the disclosure. Thus, the present disclosure can include modifications and variations that are within the scope of the appended claims and their equivalents.

Claims

What is claimed is:

1. An apparatus for removing gaseous carbon dioxide from a process gas, the apparatus comprising: a housing comprising one or more walls having one or more inner surfaces defining an interior cavity, the one or more walls comprise a one or more openings, a sorbent bed disposed within the housing, the sorbent bed occupying a sorbent bed volume within the interior cavity, at least one electrode configured to intermittently contact the sorbent bed.

2. The apparatus of claim 1 wherein the one or more walls comprise a first opening and a second opening.

3. The apparatus of claim 2 wherein the first and second openings are disposed opposite to each other.

4. The apparatus of claim 1 wherein the sorbent bed comprises opposing first and second ends.

5. The apparatus of claim 4 wherein a first electrode is configured to intermittently contact the first end of the sorbent bed.

6. The apparatus of claim 5 wherein a second electrode is configured to intermittently contact the second end of the sorbent bed.

7. The apparatus of claim 1 wherein the at least one electrode is configured to form a gas tight seal on the sorbent bed when in contact with the sorbent bed.

8. The apparatus of claim 1 wherein the sorbent bed comprises a honeycomb structure comprised of a plurality of walls forming a plurality of channels extending from a first end of the sorbent bed to the second end of the sorbent bed.

9. A method of removing CO2 from a process gas, the method comprising at least one cycle comprising the steps of: adsorbing CO2 gas from the process gas and holding the adsorbed CO2 gas with a sorbent bed; and heating the sorbent bed with one or more electrodes to release at least some of the adsorbed CO2 gas from the sorbent bed; wherein the heating step occurs after the absorbing step; and wherein the one or more electrodes are removably in contact with the sorbent bed during the heating step.

10. The method of claim 9 wherein the one or more electrodes are in contact with the sorbent bed only during the heating step.

11. The method of claim 9 wherein the one or more electrodes are removed from contact with the sorbent bed in one or more steps other than the heating step.

12. The method of claim 9 wherein the one or more electrodes are removed from contact with the sorbent bed in every step other than the heating step.

13. The method of claim 9 wherein the one or more electrodes prevent gas flow into or out of the sorbent bed during the heating step.

14. The method of claim 9 wherein the one or more electrodes prevent gas flow into and out of the sorbent bed during the heating step.

15. The method of claim 9 wherein the sorbent bed is disposed within a sorbent bed volume within a housing, and the sorbent bed volume is essentially gas tight during the heating step.

16. The method of claim 9 wherein the process gas flows into the sorbent bed during the absorption step.

17. The method of claim 9 wherein the sorbent bed volume is gas purged during a purging step after the heating step.

18. A method of removing CO2 from a process gas, the method comprising at least one cycle comprising the steps of: adsorbing CO2 by exposing the process gas to a sorbent bed, wherein at least a portion of the CO2 in the process gas is removed from the process gas and held by the sorbent bed , wherein the sorbent bed is disposed in a sorbent bed volume defined by a housing in which the sorbent bed resides; heating the sorbent bed to desorb at least a portion of the CO2 from the sorbent bed (“desorbed CO2”), wherein essentially no gas escapes from the sorbent bed volume, wherein the heating comprises applying an electric potential to the sorbent bed; and purging the desorbed CO2 from the sorbent bed volume.

19. The method of claim 18 wherein, during the heating step, essentially no gas enters the sorbent bed volume.

20. The method of claim 18 wherein the process gas flows over, onto, and / or through the sorbent bed.

21. The method of claim 18 wherein the purging comprises introducing a fluid medium into the sorbent bed volume to create a desorb fluid comprising the desorbed CO2.

22. The method of claim 21 wherein the fluid medium comprises water vapor or steam or both.

23. The method of claim 21 wherein the desorb fluid is forcibly removed from the container.

24. The method of claim 23 further comprising CO2 is separated from the desorb fluid via condensation of the water vapor or the steam or both.

25. The method of claim 18 wherein the applying the electric potential comprises contacting the sorbent bed with one or more electrodes.

26. The method of claim 25 wherein at least one of the one or more electrodes comprises an electrically conductive contact element for contacting the sorbent bed.

27. The method of claim 26 wherein the electrically conductive contact element comprises graphite, wire mesh, or combinations thereof.

28. The method of claim 26 wherein the electrically conductive contact element is connected to one pole of an electric power supply.

29. The method of claim 28 wherein the electrode further comprises an support element for supporting the electrically conductive contact element.

30. The method of claim 29 wherein the support element is electrically insulating.

31. The method of claim 29 wherein the electrode further comprises an electrically insulating of element disposed between the support element and the electrically conductive contact element.

32. The method of claim 25 wherein none of the one or more electrodes is disposed inside the sorbent bed.

33. The method of claim 25 wherein during the heating step, no convective heat losses occur from the sorbent bed volume.

34. The method of claim 25 wherein during the heating step, the one or more electrodes prevent flow into and out of the sorbent bed volume.

35. The method of claim 34 wherein, during the adsorbing step, the one or more electrodes do not prevent flow into and out of the sorbent bed volume.

36. The method of claim 34 wherein, during the purging step, the one or more electrodes do not prevent flow into and out of the sorbent bed volume.

37. The method of claim 25 wherein, during the adsorbing and the purging, the one or more electrodes do not prevent flow into and out of the sorbent bed volume.

38. The method of claim 25 wherein the one or more electrodes are brought into, and out of, contact with the sorbent bed by one or more actuators.

39. The method of claim 38 wherein at least one of the one or more actuators is driven pneumatically.

40. The method of claim 38 wherein at least one of the one or more actuators is driven hydraulically.

41. The method of claim 38 wherein at least one of the one or more actuators is driven by an electric motor.

42. The method of claim 25 wherein, during the adsorbing, the one or more electrodes do not contact the sorbent bed.

43. The method of claim 25 wherein, during the purging, the one or more electrodes do not contact the sorbent bed.

44. The method of claim 25 wherein, during the adsorbing and the purging, the one or more electrodes do not contact the sorbent bed.

45. The method of claim 25 wherein during the adsorbing step the CCh-ladcn process gas enters the container and contacts an inlet surface of the sorbent bed, and passes over or through the sorbent bed, and during the heating step at least one of the electrodes covers at least a portion of the inlet surface thereby preventing essentially all gas flow to the sorbent bed.

46. The method of claim 45 wherein the inlet surface is completely covered by one or more of the electrodes.

47. The method of claim 45 wherein during the heating step, no electrodes cover the outlet surface.

48. The method of claim 45 wherein, during the heating step, at least one of the electrodes covers at least a portion of the outlet surface.

49. The method of claim 25 wherein during the adsorbing step the process gas exits the container from an outlet surface of the sorbent bed, wherein the adsorbed CO2 remains in the sorbent bed, and during the heating step at least one of the electrodes covers at least a portion of the outlet surface thereby preventing essentially all gas flow from the sorbent bed.

50. The method of claim 49 wherein the outlet surface is completely covered by one or more of the electrodes.

51. The method of claim 49 wherein during the heating step, no electrodes cover the inlet surface.

52. The method of claim 49 wherein, during the heating step, at least one of the electrodes covers at least a portion of the inlet surface.

53. The method of claim 25 wherein during the adsorbing step the process gas enters the container and contacts an inlet surface of the sorbent bed, and passes over or through the sorbent bed, and during the heating step at least one of the electrodes covers the inlet surface thereby preventing essentially all gas flow to the sorbent bed.

54. The method of claim 25 wherein during the adsorbing step the process gas exits the container from an outlet surface of the sorbent bed, wherein the adsorbed CO2 remains in the sorbent bed, and during the heating step at least one of the electrodes covers the outlet surface thereby preventing essentially all gas flow from the sorbent bed.

55. The method of claim 18 wherein no gas escapes from the container during the heating step.

56. The method of claim 18 further comprising, after the adsorbing step and before the heating step, a step of evacuating at least a portion of any gaseous species which may be present inside the container.

57. The method of claim 56 wherein the gaseous species is evacuated by applying a vacuum.

58. The method of claim 57 wherein the vacuum is applied by a vacuum pump.

59. The method of claim 57 wherein the vacuum is applied by exposing an interior of the container to a lower pressure which is below a pressure of any gaseous species present in the container.

60. The method of claim 56 wherein the gaseous species is selected from the group consisting of CO2, N2, O2, and combinations thereof.

61. The method of claim 56 further comprising, after the purging step or the evacuating step, a step of cooling the sorbent material with a cooling gas stream which is free or essentially free of any oxygen gas species.

62. The method of claim 61 wherein the cooling gas stream comprises nitrogen, water vapor, or steam, or combinations thereof.

63. The method of claim 18 wherein the sorbent bed is electrically conductive.

64. The method of claim 18 wherein, during the heating step, greater than 0.05 watts per gram (W / g) of sorbent bed are applied to the sorbent bed.

65. The method of claim 25 wherein the one or more electrodes are comprised of a material which contacts the sorbent bed during the heating step, the material having an electrical resistance less than 100 ohms.

66. The method of claim 65 wherein the one or more electrodes are comprised of a material selected from the group consisting of conductive fluorosilicone elastomer, conductive rubber sheet, conductive foam, copper foil on polymeric foam, stainless steel wire mesh on polymeric foam, and combinations thereof.

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