CO2 SCRUBBER WITH MOVING BED STRUCTURE

Abstract

A carbon dioxide scrubber includes an adsorption chamber through which an adsorption airflow is directed, a regeneration chamber through which a regeneration airflow is directed, and a divider wall separating the adsorption chamber from the regeneration chamber. A carbon dioxide sorbent bed extends across the adsorption chamber and the regeneration chamber. The carbon dioxide sorbent bed is configured to adsorb carbon dioxide from the adsorption airflow into the sorbent bed and exhaust carbon dioxide from the carbon dioxide sorbent bed into the regeneration airflow. The carbon dioxide sorbent bed is continuously movable through the adsorption chamber and the regeneration chamber.

Claims

1. A carbon dioxide scrubber, comprising: an adsorption chamber through which an adsorption airflow is directed; a regeneration chamber through which a regeneration airflow is directed; a divider wall separating the adsorption chamber from the regeneration chamber; and a carbon dioxide sorbent bed configured extending across the adsorption chamber and the regeneration chamber, the carbon dioxide sorbent bed configured to adsorb carbon dioxide from the adsorption airflow into the sorbent bed and exhaust carbon dioxide from the carbon dioxide sorbent bed into the regeneration airflow; wherein the carbon dioxide sorbent bed is continuously movable through the adsorption chamber and the regeneration chamber.

2. The carbon dioxide scrubber of claim 1, further comprising a heater disposed in the regeneration chamber configured to heat the regeneration airflow.

3. The carbon dioxide scrubber of claim 1, wherein the carbon dioxide sorbent bed is a carbon dioxide sorbent wheel rotatable about a central axis.

4. The carbon dioxide scrubber of claim 1, wherein the carbon dioxide sorbent bed is a belt extending about a first drive wheel disposed in the adsorption chamber and a second drive wheel disposed in the regeneration chamber, the carbon dioxide sorbent bed circulated between the adsorption chamber and the regeneration chamber by rotation of the first drive wheel and the second drive wheel.

5. The carbon dioxide scrubber of claim 4, wherein the carbon dioxide sorbent bed is a corrugated belt.

6. The carbon dioxide scrubber of claim 1, further comprising a recirculation chamber configured to recirculate the regeneration airflow through the regeneration chamber.

7. The carbon dioxide scrubber of claim 1, wherein the carbon dioxide sorbent bed comprises one or more of activated carbon, carbon fiber, zeolite, molecular sieve, polymer fibers, metal organic framework (MOF), a metal oxide or amine or amine functionality containing material supported by at least one of porous material such as silica, carbon, clay or metal oxide in granular or pelleted shape solids or fiber form.

8. The carbon dioxide scrubber of claim 1, further comprising a secondary sorbent bed configured extending across the adsorption chamber and the regeneration chamber, the secondary sorbent bed configured to adsorb a secondary material from the adsorption airflow into the sorbent bed and exhaust the secondary material from the secondary sorbent bed into the regeneration airflow; wherein the secondary sorbent bed is continuously movable through the adsorption chamber and the regeneration chamber.

9. The carbon dioxide scrubber of claim 8, wherein the secondary sorbent bed is a belt extending between the adsorption chamber and the regeneration chamber.

10. The carbon dioxide scrubber of claim 8, wherein the secondary sorbent bed is configured to adsorb one or more of H2O, HCHO or volatile organic compounds from the adsorption airflow.

11. The carbon dioxide scrubber of claim 1, further comprising a heat exchanger configured to recover thermal energy from an exhaust portion of the regeneration airflow downstream of the regeneration chamber.

12. The carbon dioxide scrubber of claim 11, wherein the heat exchanger is configured to transfer the recovered thermal energy to an inlet portion of the regeneration airflow upstream of the regeneration chamber.

13. The carbon dioxide scrubber of claim 11, wherein the heat exchanger is one of a heat recovery ventilation heat exchanger or a direct expansion heat pump.

14. An air handling unit comprising: a housing; a return air damper through which a return airflow is directed into the air handling unit; a supply air damper through which a supply airflow is directed from the air handling unit into a conditioned space; one or more of a heating coil and a cooling coil disposed in the housing configured to alter a temperature of the return airflow in the housing; a carbon dioxide scrubber operably connected to the air handling unit, the carbon dioxide scrubber including: an adsorption chamber through which an adsorption airflow is directed; a regeneration chamber through which a regeneration airflow is directed; a divider wall separating the adsorption chamber from the regeneration chamber; and a carbon dioxide sorbent bed configured extending across the adsorption chamber and the regeneration chamber, the carbon dioxide sorbent bed configured to adsorb carbon dioxide from the adsorption airflow into the sorbent bed and exhaust carbon dioxide from the carbon dioxide sorbent bed into the regeneration airflow; wherein the carbon dioxide sorbent bed is continuously movable through the adsorption chamber and the regeneration chamber; wherein the adsorption airflow is directed from the housing into the adsorption chamber and returned from the adsorption chamber into the housing.

15. The air handling unit of claim 14, wherein the adsorption airflow is directed into the adsorption chamber from downstream of the cooling coil and is returned into the housing upstream of the heating coil.

16. The air handling unit of claim 14, wherein the regeneration airflow is directed into the regeneration chamber from the housing at a location downstream of the heating coil of the air handling unit.

17. The air handling unit of claim 14, wherein: the cooling coil is an evaporator of a vapor compression cycle; and the heating coil is powered by a furnace.

18. The air handling unit of claim 17, wherein the regeneration airflow is directed across a condenser of the vapor compression cycle prior to entering the regeneration chamber.

19. A heating, ventilation and air conditioning and carbon dioxide scrubbing system, comprising: a terminal heating, ventilation and air conditioning (HVAC) system disposed at a conditioned space, the terminal HVAC system configured to condition a return airflow and supply the airflow to the conditioned space; and a carbon dioxide scrubber operably connected to the air handling unit, the carbon dioxide scrubber including: an adsorption chamber through which an adsorption airflow is directed; a regeneration chamber through which a regeneration airflow is directed; a divider wall separating the adsorption chamber from the regeneration chamber; and a carbon dioxide sorbent bed configured extending across the adsorption chamber and the regeneration chamber, the carbon dioxide sorbent bed configured to adsorb carbon dioxide from the adsorption airflow into the sorbent bed and exhaust carbon dioxide from the carbon dioxide sorbent bed into the regeneration airflow; wherein the carbon dioxide sorbent bed is continuously movable through the adsorption chamber and the regeneration chamber; wherein the adsorption airflow is directed from the conditioned space into the absorption chamber and returned from the adsorption chamber into the conditioned space.

20. The heating, ventilation and air conditioning and carbon dioxide scrubbing system of claim 19, further comprising: a direct outside air system configured to direct a flow of outside air into the conditioned space; wherein the regeneration airflow is directed into the regeneration chamber from the direct outside air system, and the regeneration airflow is directed from the regeneration chamber to ambient.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike:

[0026] FIG. 1 is a schematic view of an embodiment of a CO.sub.2 scrubber;

[0027] FIG. 2 is a schematic view of an embodiment of a sorbent bed of a CO.sub.2 scrubber;

[0028] FIG. 3 is a schematic view of another embodiment of a CO.sub.2 scrubber;

[0029] FIG. 4 is a schematic view of yet another embodiment of a CO.sub.2 scrubber;

[0030] FIG. 5 is a schematic view of an embodiment of a CO.sub.2 scrubber having thermal energy recovery;

[0031] FIG. 6 is a schematic view of another embodiment of a CO.sub.2 scrubber having thermal energy recovery;

[0032] FIG. 7 is a schematic view of an embodiment of a terminal HVAC system including a CO.sub.2 scrubber;

[0033] FIG. 8 is a schematic view of another embodiment of a terminal HVAC system including a CO.sub.2 scrubber;

[0034] FIG. 9 is a schematic view of an embodiment of an air handling unit including a CO.sub.2 scrubber;

[0035] FIG. 10 is a schematic view of another embodiment of an air handling unit including a CO.sub.2 scrubber;

[0036] FIG. 11 is a schematic view of an embodiment of a roof top unit (RTU) including a CO.sub.2 scrubber;

[0037] FIG. 12 is a schematic view of an embodiment of a CO.sub.2 scrubber including an H.sub.2O sorbent bed;

[0038] FIG. 13 is a schematic view of another embodiment of a CO.sub.2 scrubber including an H.sub.2O sorbent bed;

[0039] FIG. 14 is a schematic view of yet another embodiment of a CO.sub.2 scrubber including an H.sub.2O sorbent bed; and

[0040] FIG. 15 is a schematic view of still another embodiment of a CO.sub.2 scrubber including an H.sub.2O sorbent bed.

DETAILED DESCRIPTION

[0041] A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the figures.

[0042] An embodiment of a carbon dioxide (CO.sub.2) scrubber 10 is shown in FIG. 1. The CO.sub.2 scrubber 10 includes a scrubber housing 12 having an adsorption chamber 14 and a regeneration chamber 16, separated by a divider wall 18. The adsorption chamber 14 includes an adsorption inlet damper 20 and an adsorption outlet damper 22. In some embodiments, an adsorption chamber fan 24 is located in the adsorption chamber 14 to urge an adsorption airflow 26 through the adsorption chamber 14. In some embodiments, the adsorption airflow 26 is an indoor airflow from a conditioned space 28 that is reintroduced to the conditioned space 28 after passing through the adsorption chamber 14.

[0043] Similarly, the regeneration chamber 16 includes a regeneration inlet damper 30 and a regeneration outlet damper 32. In some embodiments, a regeneration chamber fan 34 is located in the regeneration chamber 16 to urge a regeneration airflow 36 through the regeneration chamber 16. In some embodiments, the regeneration airflow 36 is an outside airflow that is exhausted to ambient after passing through the regeneration chamber 16. In some embodiments, a direction of flow of the adsorption airflow 26 through the adsorption chamber 14 is opposite to a direction of flow of the regeneration airflow 36 through the regeneration chamber 16.

[0044] A moving sorbent bed 38 is located in the scrubber housing 12 and spans across the adsorption chamber 14 and the regeneration chamber 16, and through the divider wall 18. The sorbent bed 38 may be formed from, for example, an activated carbon material or a carbon material impregnated with amine materials, or other materials to adsorb CO.sub.2 from the adsorption airflow 26. In some embodiments the sorbent bed 38 may include but is not limited to activated carbon, carbon fiber, zeolite, molecular sieve, polymer fibers, metal organic framework (MOF) and metal oxide known to react with CO.sub.2 such as calcium, lithium and magnesium; and amine or amine functionality containing material supported by at least one of porous material such as silica, carbon, clay or metal oxide in granular or pelleted shape solids or fiber form. Additionally, the sorbent bed 38 may include materials to adsorb other materials in the adsorption airflow 26, such as HCHO or volatile organic compounds (VOCs). In the embodiment of FIG. 1, and as shown in FIG. 2, the moving sorbent bed 38 is a rotating wheel configuration with an axis of rotation 40 located at the divider wall 18. The sorbent bed 38 is operably connected to a power source (not shown) to drive rotation of the sorbent bed 38 about the axis of rotation 40. A heater 44 is located in the regeneration chamber 16 upstream of the sorbent bed 38. The heater 44 may be, for example, a radiative or microwave heater. Alternatively, waste heat may be used to regenerate the sorbent via an air flow heat exchanger or a heat conduction

[0045] In operation of the CO.sub.2 scrubber 10, the sorbent bed 38 continuously rotates about the axis of rotation 40. As the sorbent bed 38 rotates, the portion located in the adsorption chamber 14 adsorbs CO.sub.2 from the adsorption airflow 26 flowing therethrough. The regeneration airflow 36 flowing into the regeneration chamber 16 via the regeneration inlet damper 30 is heated by the heater 44 and proceeds to the sorbent bed 38, where the sorbent bed 38 is regenerated by removal of the CO.sub.2 from the sorbent bed 38 by the heated regeneration airflow 36, or heated directly by the heater 44 if it is radiative or microwave type heater. The regeneration airflow 36 is then exhausted to ambient through the regeneration outlet damper 32, and air ducts, if included.

[0046] In some embodiments, the CO.sub.2 scrubber 10 includes a recirculation chamber 46 connected to the regeneration chamber 16 by a recirculation damper 48, which when opened, recirculates the regeneration airflow 36 through the regeneration chamber 16.

[0047] Another embodiment is illustrated in FIG. 3, in which the sorbent bed 38 has a belt configuration extending between a first drive wheel 49 located in the adsorption chamber 14 and a second drive wheel 50 located in the regeneration chamber 16. The sorbent bed 38 may include one or more sorbent materials disposed on a carrier 120. The carrier 120 may be a benign material configured to support the sorbent material without overly restricting airflow therethrough. For example, the carrier material 120 may be porous or pervious to airflow, such as a paper of cloth as is used in the construction of filters. The sorbent bed 38 may include one or more sorbent materials disposed onto a porous carrier material, such as an organic or polymeric thread or fiber or woven structure. At least one of the first drive wheel 49 and the second drive wheel 50 is powered to drive circulation of the sorbent bed 38 between the adsorption chamber 14 and the regeneration chamber 16. As shown in FIG. 3, the sorbent bed 38 may be a flat belt configuration, or a corrugated belt configuration such as shown in FIG. 4, having a plurality of corrugations 52. The plurality of corrugations 52 may be V-shaped, such as shown, or may have another shape such as U-shaped or curved-shape. In some embodiments, such as shown in FIG. 4, the heater 44 may be located between an upstream portion 54 and a downstream portion 56 of the sorbent bed 38.

[0048] Referring to FIG. 5, a heat recovery ventilation (HRV) heat exchanger 58 is utilized to recover thermal energy from an exhaust portion 36a of the regeneration airflow 36 at an exhaust duct 60 connected to the regeneration outlet damper 32 and transfer the recovered thermal energy to an inlet portion 36b of the regeneration airflow 36 at an inlet duct 62 connected to the regeneration inlet damper 30. In some embodiments, the HRV heat exchanger 58 is a plate type air to air heat exchanger, but one skilled in the art will readily appreciate that other types of heat exchangers may be utilized, such as a 2-phase thermosiphon or a gravity-based diode heat pipe may be utilized.

[0049] In another embodiment, illustrated in FIG. 6, a direct expansion (DX) type heat pump 64 is located across the exhaust duct 60 and the inlet duct 62 to extract thermal energy from the exhaust portion 36a and transfer the thermal energy to the inlet portion 36b. Thermal energy recovery via the heat exchanger 58 or the heat pump 64 improves efficiency of the CO.sub.2 scrubber 10 by reducing energy consumption of the heater 44 to raise the temperature of the regeneration airflow 36 to a desired temperature for regeneration of the sorbent bed 38.

[0050] In an embodiment illustrated in FIG. 7, the CO.sub.2 scrubber 10 is used in conjunction with a heating, ventilation and air conditioning (HVAC) system 66, which is a terminal HVAC system, such as a fan coil unit with a thermal fluid circulated therethrough, or a DX system. Such an HVAC system 66 is at least partially located in the conditioned space 28, and conditions a return airflow 68 entering the HVAC system 66 from the conditioned space 28 and outputs a conditioned supply airflow 70 into the conditioned space 28. In some embodiments, a dedicated outdoor air system (DOAS) 72 provides a continuous flow of outside airflow into the conditioned space 28.

[0051] The CO.sub.2 scrubber 10 is located in the conditioned space 28. In this embodiment, the adsorption airflow 26 is directed from the conditioned space 28 into the adsorption chamber 14 and returned to the conditioned space 28 after passing across the sorbent bed 38. The regeneration airflow 36 is not an outside airflow but is also airflow directed from the conditioned space 28 into the regeneration chamber 16. Once the regeneration airflow 36 passes across the sorbent bed 38, the regeneration airflow 36 is exhausted to ambient via the regeneration outlet damper 32. Such a configuration improves IAQ of the conditioned space 28 by removing CO.sub.2 therefrom, and also reduces the airflow requirements of the DOAS 72. Alternatively, in another embodiment illustrated in FIG. 8, the regeneration airflow 36 is provided from the DOAS 72.

[0052] Referring to FIGS. 9 and 10, the CO.sub.2 scrubber 10 is incorporated into an air handling unit (AHU) 74. The AHU 74 includes an AHU housing 76 having a return air damper 78 through which a return airflow 80 is admitted to the AHU 74 from the conditioned space 28. A supply airflow damper 82 directs a supply airflow 84 from the AHU 74 into the conditioned space 28. Further, the AHU 74 may include an outside air damper 86 to admit an outside airflow 88 into the AHU 74. Further, the AHU 74 may include a filter 90, a cooling coil 92 to cool airflow in the AHU 74, and/or a heating coil 94 to heat airflow in the AHU 74. An AHU fan 96 may be disposed in the AHU housing 76 to urge airflow through the AHU 74. In the embodiment of FIG. 9, the CO.sub.2 scrubber 10 is coupled to the AHU 74 such that the adsorption airflow 26 is directed from the AHU 74 into the adsorption chamber 14, and directed from the adsorption chamber 14 back into the AHU 74. The regeneration airflow 36 is directed from outside of the AHU 74 into the regeneration chamber 16 and from the regeneration chamber 16 to outside of the AHU 74. In this embodiment, outside of the AHU 74 may correspond to ambient. In some embodiments, the CO.sub.2 scrubber 10 is positioned such that the adsorption airflow 26 is admitted into the adsorption chamber 14 downstream of the cooling coil 92 and is returned to the AHU 74 upstream of the heating coil 94.

[0053] Referring now to FIG. 10, in this embodiment, the regeneration inlet damper 30 is located in the AHU 74 such that the regeneration airflow 36 is admitted to the regeneration chamber 16 from the AHU 74 at a location, for example, downstream of the heating coil 94. After flowing across the sorbent bed 38, the regeneration airflow 36 is exhausted to ambient via the regeneration outlet damper 32.

[0054] In another embodiment, such as shown in FIG. 11, the AHU 74 may be part of a rooftop HVAC system. In the rooftop HVAC system configuration, the heating coil 94 is an air-to-air heating coil 94 driven by a furnace 100, and the cooling coil 92 is an evaporator, which is part of a vapor compression cycle. The vapor compression cycle includes a condenser 102 located outside of the AHU housing 76. Condenser airflow 104 is driven across the condenser 102 by a condenser fan 106. The regeneration inlet damper 30 is located near the condenser 102, such that heated condenser airflow 104 is directed into the regeneration inlet damper 30. Further, the heating coil 94 may be configured to pass across the regeneration chamber 16. This configuration takes advantage of the heat of the condenser 102 during cooling seasons and/or the heating coil 94 during heating seasons to improve regeneration efficiency and reduce the amount of heat needed to be input via the heater 44 of the CO.sub.2 scrubber 10.

[0055] Referring to FIG. 12, the CO.sub.2 scrubber 10 includes a CO.sub.2 sorbent bed 38 and a secondary sorbent bed 110, such as a desiccant to remove H.sub.2O from the adsorption airflow 26. In other embodiments, the secondary sorbent bed 110 may be configured to remove other gases, such as HCHO or volatile organic compounds (VOCs) from the adsorption airflow 26. Further, in some embodiments the secondary sorbent bed 110 and the CO.sub.2 sorbent bed 38 may be disposed on a common carrier, in for example, alternating adjacent positions along the carrier. Both the CO.sub.2 sorbent bed 38 and the desiccant could be regenerated through the hot air stream, thus synergy could be created. The secondary sorbent bed 110 may be a moving belt configuration extending across the adsorption chamber 14 and the regeneration chamber 16. H.sub.2O in the adsorption airflow 26 is adsorbed by the secondary sorbent bed 110 in the adsorption chamber 14 and the secondary sorbent bed 110 is regenerated at the regeneration chamber 16 by the regeneration airflow 36.

[0056] In another embodiment, shown in FIG. 13, the sorbent bed 38 is a corrugated belt configuration, in which a first leg 38a of a corrugation is a CO.sub.2 sorbent material, while a second leg 38b is a desiccant material for H.sub.2O adsorption. Further, as shown in FIG. 12, the heater 44 may be located in the regeneration chamber 16 upstream of both the CO.sub.2 sorbent bed 38 and the secondary sorbent bed 110. The heater 44, though, may be located to heat only a portion of the secondary sorbent bed 110, such as directly upstream of the secondary sorbent bed 110 such as in FIG. 14, or as shown in FIG. 15 between a first leg 110a of the secondary sorbent bed 110 and a second leg 110b of the secondary sorbent bed 110.

[0057] The configurations of CO.sub.2 scrubbers 10 disclosed herein have the technical effect of being continuously operated, thus there is no separate regeneration mode in which the CO.sub.2 is not being adsorbed. Because of continuous operation and regeneration, a smaller volume of sorbent material may be utilized in the sorbent bed 38. Further the CO.sub.2 scrubber allows for reduction in the outside air volume flow volumes for ventilation and reduces the amount of potentially polluted outside air admitted into the conditioned space 28.

[0058] The term “about” is intended to include the degree of error associated with measurement of the particular quantity based upon the equipment available at the time of filing the application.

[0059] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, element components, and/or groups thereof.

[0060] While the present disclosure has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made, and equivalents may be substituted for elements thereof without departing from the scope of the present disclosure. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from the essential scope thereof. Therefore, it is intended that the present disclosure not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this present disclosure, but that the present disclosure will include all embodiments falling within the scope of the claims.