Carbon-negative combustion through the use of molecular transfer systems and disguisement of gas constituents

Abstract

Disclosed are methods, processes, systems, and compositions of matter that enable the transfer of targeted constituents from a dilute state to a final concentrated state. Exemplary dilute constituents are carbon dioxide or humidity as found in air or other gases; and exemplary final states, respectively, are purified carbon dioxide or condensed water. Such transfer from dilute sources is understood generally to require more energy consumption as the source phase becomes more dilute in the targeted constituent. The present invention shows how a different governing principle, i.e. reactive disguisement, is applied to create a concentrated final state without relying on heat flow or pressure swings to actively concentrate a targeted constituent. The primary field of invention is chemical separation.

Claims

1-22. (canceled)

23. A process for removing CO2 from air; creating a mixture of CO2 and O2; sufficiently concentrating the CO2 while retaining a balance of O2; relaying the CO2-O2 mixture toward the combustor of an oxygen-fueled combustor that is part of a semi-open CO2-based power cycle; combusting the CO2-O2 mixture with a mixture of hydrocarbons; separating, recycling, and exporting the resultant CO2 and H2O as in the semi-open Allam-Fetvedt cycle.

Description

5. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] FIG. 1A is a schematic diagram of a capture unit, which is enabled for unidirectional gas flow through a stationary phase.

[0037] FIG. 1B is a schematic diagram of a capture unit, which is enabled for bidirectional gas flow through a stationary phase.

[0038] FIG. 2A is a pressure-enthalpy diagram for oxygen, illustrating thermodynamic transitions.

[0039] FIG. 3B is a schematic diagram showing gas production from a water electrolysis unit, which provides reactive sweep gas to the capture unit.

[0040] FIG. 4 is a schematic diagram showing a dynamic pressure adjustment system that employs a high-pressure gas such as pipelined natural gas.

[0041] FIG. 5A is a schematic diagram that shows the capture unit, which uses an oxygen stream as a reactive sweep stream in order to produce a spent reactive sweep stream that ultimately is combusted.

[0042] FIG. 5B is a schematic diagram that shows the capture unit 1B, which uses a methane stream 15 as a reactive sweep stream in order to produce a spent reactive sweep stream 5 that ultimately is converted by reaction in a fuel cell.

[0043] FIG. 6 is a schematic diagram of a capture unit which is enabled for bidirectional gas flow through a stationary phase and for full fluidization.

[0044] FIG. 100 is a simplified block flow diagram of a gas-fed Allam Cycle.

[0045] FIG. 130 is a simplified block flow diagram of a gas-fed Allam Cycle that is modified by the addition of Post-Emission Capture (PEC) system.

[0046] FIG. 135 is a simplified block flow diagram of a modified gas-fed Allam Cycle that is further modified by the addition of PEC system 130 in a highly preferred embodiment.

[0047] FIG. 140 is a simplified block flow diagram of a modified gas-fed Allam Cycle that is further modified by the addition of PEC system.

[0048] FIG. 150 is a simplified block flow diagram of a modified gas-fed Allam Cycle that is further modified by the addition of an alternative PEC system that accepts a hydrocarbon (HC) inlet stream and that produces a hydrocarbon feed (HCF) stream for the combustor.

[0049] FIG. 160 is a simplified block flow diagram of a modified gas-fed Allam Cycle that is further modified by the addition of an alternative PEC system that accepts the hydrocarbon (HC) stream into the NG stream.

[0050] FIG. 170 is a simplified block flow diagram of a portion of the coal-fed Allam Cycle.

[0051] FIG. 175 is a simplified block flow diagram of a portion of a coal-fed Allam Cycle that is modified by the addition of Post-Emission Capture (PEC) system.

[0052] FIG. 180 is a simplified block flow diagram of a portion of a modified coal-fed Allam Cycle that is further modified by the addition of PEC system.

[0053] FIG. 185 is a simplified block flow diagram of a portion of a modified coal-fed Allam Cycle that is further modified by the addition of an alternative PEC system that accepts a hydrocarbon (HC) inlet stream and that produces a hydrocarbon feed (HCF) stream for the combustor.

[0054] FIG. 190 is a simplified block flow diagram of a portion of a modified coal-fed Allam Cycle that is further modified by the addition of an alternative PEC system 130 that accepts the hydrocarbon (HC) stream 210 into the syngas stream.

[0055] FIG. 195 is a simplified block flow diagram of a portion of a modified coal-fed Allam Cycle that is further modified by the addition of an alternative PEC system 130 in a highly preferred embodiment.

[0056] FIG. 200 illustrates the inputs to and subsystems of PEC system.

[0057] FIG. 210 illustrates the inputs to and subsystems of PEC system, with a modified operating procedure.

[0058] FIG. 220 illustrates the inputs to and subsystems of PEC system, with a modified sequence of introduced constituents.

[0059] FIG. 230 illustrates the inputs to and subsystems of a PEC system.

[0060] FIG. 240 illustrates the inputs to and subsystems of a PEC system, with a modified operating procedure.

[0061] FIG. 300 illustrates an arrangement of subunits for a basic subsystem of a PEC system.

[0062] FIG. 310 illustrates an arrangement of subunits for a PEC subsystem that employs a separate dehydration step.

[0063] FIG. 320 illustrates an arrangement of subunits for another PEC subsystem that employs a separate dehydration step.

[0064] FIG. 330 illustrates a parallel arrangement of subsystems that enable reduction of pressure loss (pressure gradient) across each subsystem.

[0065] FIG. 400 illustrates one embodiment of a capture subunit.

[0066] FIG. 410 illustrates another embodiment of a capture subunit.

[0067] FIG. 420 illustrates yet another embodiment of a capture subunit.

[0068] FIG. 430 illustrates yet another embodiment of a capture subunit.

[0069] FIG. 440 illustrates another embodiment of a capture subsystem.

[0070] FIG. 500 illustrates an arrangement of subunits for a PEC subsystem that employs a pressure and thermal management method.

[0071] FIG. 510 illustrates an arrangement of subunits for a PEC subsystem that employs an alternative pressure and thermal management method.

[0072] FIG. 520 illustrates an arrangement of subunits for a PEC subsystem that employs an alternative pressure and thermal management method described in association with FIG. 510.

[0073] FIG. 550 illustrates the arrangement of parallel systems that utilize the method described in association with FIG. 520 for the purpose of providing natural convection drive.

[0074] FIG. 560 illustrates the use of a heat pipe for the purpose of transferring heat.

[0075] FIG. 900 is a simplified block flow diagram of an alternative Post-Emission Capture (PEC) process that is suitable for a CCS-enabled power plant.

[0076] FIG. 910 illustrates the inputs to and subsystems of a PEC system, which is associated with FIG. 900.

[0077] FIG. 1000 is a simplified block flow diagram for a conventional solvent-based carbon dioxide capture process.

[0078] FIG. 1010 is a simplified block flow diagram for a modified solvent-based carbon dioxide capture process, wherein a natural gas stream is used to desorb CO2 from the regenerator.

[0079] FIG. 1020 is a simplified block flow diagram for a modified solvent-based carbon dioxide capture process, wherein a natural gas stream is used to partially desorb CO2 from a primary regenerator.

[0080] FIG. 2100 is a schematic that illustrates the possibilities for and logic of reactive disguisement.

[0081] FIG. 2200 is a block flow diagram that illustrates an adsorbent-based DAC system with four stages.

[0082] FIG. 2250 is a schematic that shows the sequence of exchanges among the four stages of the adsorbent-based DAC system.

6. DETAILED DESCRIPTION OF THE INVENTION

[0083] The following description is made for the purpose of illustrating the general principles of the present invention and is not meant to limit the inventive concepts claimed herein. Features described herein can be used in combination with other described features in each of the various possible combinations.

[0084] In accordance with one aspect of the presently disclosed inventive concepts, a method of non-thermally regenerating a stationary phase containing constituents that were captured from a second phase (i.e., the initial gas phase containing targeted constituents) includes contacting said stationary phase with a reactive sweep gas. The reactive sweep gas is capable of being chemically oxidized or reduced, or otherwise converted. The stationary phase is a sorbent such as a zeolite, metal organic framework (MOF), polymer, carbohydrate, or carbonaceous material. The targeted constituents become and are referred to as captured constituents—they are one or more gas species that have an affinity for the stationary phase. Specifically, carbon dioxide and/or moisture are targeted constituents in the examples of the inventive matter provided herein.

[0085] FIG. 1A is a schematic diagram of a capture unit, i.e. Element 1, which is enabled for unidirectional gas flow through a stationary phase. Element 1 is a vessel (a.k.a., Vessel 1) that consists of a confined stationary phase. The stationary phase is a packed bed consisting of one or more sorbent materials. The bed operates in either a stationary mode or a bubbling mode, depending on the particle size distribution and gas velocity through the bed. Element 2 is the inlet gas stream and Element 3 is the outlet gas stream for Vessel 1—they are also termed Stream 2 and Stream 3, respectively. In the configuration shown in FIG. 1A, the gas flow occurs upward (i.e. against gravity) through the column, which is vertically oriented with respect to ground. In this configuration, the composition of Stream 2 alternates between an initial gas that delivers targeted constituents to the stationary phase (capture step) and a reactive sweep gas that receives the targeted constituents from the stationary phase (regeneration step). During the capture step, Stream 2 is relatively rich in the targeted constituents while Stream 3 is relatively lean in the targeted constituents, until the stationary phase becomes saturated. After that time, the composition of Stream 2 is switched to deliver the reactive sweep gas. The reactive sweep gas flows through the stationary phase, receiving the targeted constituents that were adsorbed, and exits as Stream 3 until there is no measurable indication of targeted constituents in Stream 3. After that time, the composition of Stream 2 is switched once again to deliver the initial gas containing targeted constituents.

[0086] FIG. 1B is a schematic diagram of a capture unit, i.e. Element 1B, which is enabled for bidirectional gas flow through a stationary phase. Element 1B is also known as Vessel 1B and it contains a confined stationary phase of sorbent that may become partially fluidized as a bubbling bed due to the upward flow of inlet gas stream 2. Stream 2 delivers an initial gas containing targeted constituents to the stationary phase, and Stream 3 removes a gas that is leaner in targeted constituents until the stationary phase becomes saturated and the composition of Streams 2 and 3 become identical. After that time, Streams 2 and 3 are closed using valves (not shown), and then Streams 4 and 5 are opened to allow the flow of reactive sweep gas in the downward direction. The transition from upward flow to downward flow reduces the macro-scale porosity of the stationary phase, creating more resistance to flow and thereby increasing the pressure drop across the stationary phase.

[0087] In preferred embodiments, the reactive sweep gas is pure oxygen. Purified oxygen is commercially available in large volumes by using demonstrated air separation techniques, e.g. cryogenic methods, and to some extent through adsorption or anion exchange techniques employing solid oxide materials. Noteworthy also is the generation of oxygen at the anode of a water electrolyzer (which concurrently generates hydrogen at the cathode). In accordance with one aspect of the presently disclosed inventive concepts, a composition for the reactive sweep fluid includes a hydrocarbon gas such as methane, ethane, propane, natural gas, synthesis gas, or another hydrocarbon gas mixture. Hydrocarbon gases are easily attained from oil and gas production and refining, but biological sources including landfills are noteworthy. In another embodiment, the reactive sweep gas is carbon monoxide or synthesis gas, i.e. a mixture of carbon monoxide and hydrogen. Synthesis gas (a.k.a. syngas) is attainable through steam-methane reforming or the gasification of coal or biomass. Noteworthy, on the other hand, is the generation of carbon monoxide by electrolysis of carbon dioxide as in the electrolyzers made by Dioxide Materials and 3M. In yet another embodiment, the reactive sweep gas is another oxidizing agent. In yet another embodiment, the reactive sweep gas is hydrogen. Most of the World's hydrogen is produced by steam-methane reforming with a water-gas shift stage.

[0088] In accordance with another aspect of the presently disclosed inventive concepts, a method of purging harmful or toxic matter from the stationary or solvent phase includes contacting the stationary or solvent phase with oxygen that is subsequently combusted. For reactive sweep gases other than oxygen, such as gases containing potent greenhouse gases (methane) or highly toxic species (carbon monoxide), the stationary phase or solvent must be flushed with oxygen prior to restarting the cycle of capturing targeted constituents from air.

[0089] In accordance with another aspect of the presently disclosed inventive concepts, a method of enhancing the above-disclosed non-thermal regeneration includes dynamically adjusting the pressure of the reactive sweep fluid to promote greater desorption of captured constituents per volume of the reactive sweep fluid used to effect the desorption. The dynamic pressure adjustment includes either the increase or decrease of pressure at a controlled rate, depending on the characteristics of the reactive sweep fluid. In most practical cases the reactive sweep gas' pressure is increased in order to enhance the desorption of the captured constituents—this is opposite to contemporary vacuum swing processes that reduce pressure to enhance desorption. The dynamic pressure adjustment can be isothermal or thermal depending on the rate and duration of pressure change, but a greater overall efficiency is attainable when the bulk gas is pressurized isothermally or near isothermally so that unnecessary heat generation and losses are limited.

[0090] FIG. 2A is a pressure-enthalpy diagram for oxygen, illustrating thermodynamic transitions. Two particular transitions, [1] and [2], are illustrated. Transitions [1] and [2] begin at near ambient conditions, i.e. 0.1 MPa (1 bar) and approximately 296 K (23 Celsius); and both transitions complete at the same pressure, i.e. 0.3 MPa. Transition [1] is isothermal, and essentially isoenthalpic in this region of phase space. On the other hand, Transition [2] is isoentropic, and thus realizes approximately 105 K increase in temperature. Alternatively, Transition [2] may be halted at a final pressure of 0.2 Mpa thereby realizing approximately 62 K increase in temperature. The pressure-enthalpy trajectory during dynamic pressure adjustment is in between Transitions [1] and [2], being neither perfectly isothermal or perfectly isoentropic. Ultimately, to attain the highest ratio of captured carbon dioxide to generated carbon dioxide, the pressure rise is minimized. These are illustrative transitions only, and similar for various other reactive sweep gases such as methane. The practitioner skilled in the art will appreciate the need to limit pressure and temperature escalation during dynamic pressure adjustment.

[0091] One approach to delivering gaseous oxygen at 1 atm and room temperature is by employing a storage vessel containing liquefied oxygen and offtaking the vapor phase while allowing it to thermally equilibrate with the surroundings as it flows to the stationary phase and thus becomes the reactive sweep gas. FIG. 3A is a schematic diagram of a storage vessel 3A and capture unit 1B. Vessel 3A contains a liquified gas (i.e. at liquid-vapor equilibrium), which is removed as a gas from the top of 3A and transported as Stream 4 to the capture unit 1B. The gas in Stream 4 warms to ambient or near ambient temperature by absorbing heat from the surroundings through the piping, or through a heat exchanger and a waste heat source (no shown). Stream 6 is used to refill the vessel 3A. However, other approaches to attaining oxygen are possible, as mentioned herein, and do not require liquefaction of gases. For example, collection of gaseous oxygen at the anode of a water electrolyzer.

[0092] FIG. 3B is a schematic diagram showing gas production from a water electrolysis unit 3B, wherein oxygen gas is generated at the anode side and transferred as Stream 4 at near ambient conditions, and wherein hydrogen gas is generated at the cathode side and transported as Stream 8. Fresh water supplies the electrolyzer as Stream 7. The flow of direct current is shown as Element 9. Commercial scale electrolyzers are available. In another embodiment, Stream 8 (hydrogen) is directed toward Vessel 1B while the oxygen stream is directed elsewhere.

[0093] In accordance with yet another aspect of the presently disclosed inventive concepts, a method of executing dynamic pressure adjustment of reactive sweep gas includes employing two vessels connected by a U-tube and containing a non-volatile fluid such as oil, wherein the first vessel is connected to a pressurized source such as pipelined natural gas and wherein the second vessel is connected to a volume of reactive sweep gas, such that the non-volatile liquid prevents mixing of gases and acts as a hydraulic mechanism for pressurizing the reactive sweep gas at a programmed rate controlled by sensors and actuators. In another embodiment, a single axis piston separates the vessels in lieu of the fluid-filled U-tube.

[0094] FIG. 4 is a schematic diagram showing a dynamic pressure adjustment system that employs a high-pressure gas such as pipelined natural gas (Stream 10) to apply pressure hydraulically to a volume of reactive sweep gas that is downstream of Valve 12 and upstream of Valve 13. The system includes two vessels 4A and 4B connected by a U-tube 14, which contains a non-volatile fluid such as oil. The non-volatile fluid fills a significant portion of vessels 4A and 4B while leaving vapor space that connects to streams 10 and 4 respectively. First, reactive sweep gas at ambient conditions is suppled via Stream 4 to the volume in the pipe 15, then valve 12 closes. Metering valve 11 opens, applying pressure to the gas in pipe 15. Metering valves 11 and 13 control the pressure and flow rate of reactive sweep gas in Vessel 1B.

[0095] In accordance with yet another aspect of the presently disclosed inventive concepts, a method of regenerating a liquid phase containing captured constituents includes contacting said liquid phase with a reactive sweep gas. The contacting of phases occurs by bubbling the reactive sweep gas through the liquid phase; alternatively, the liquid phase may be atomized and dispersed through the reactive sweep gas phase prior to a collection step that removes the regenerated liquid. The liquid phase is a solvent such as a hydroxide solution such as potassium hydroxide, an amine solution such as ethanolamine, ocean water, an ionic liquid, or another liquid that has a physical and/or chemical affinity for the captured constituents. The regeneration may be conducted non-thermally, but in practical cases the liquid phase is heated in order to increase the driving force for removal of captured constituents. The temperature of the reactive sweep gas may equal ambient temperature, or it may be elevated to match the solvent's temperature. A chemical engineering practitioner that is skilled in the art would be capable of designing a variety of gas-liquid contactors to execute the described regeneration.

[0096] In accordance with yet another aspect of the presently disclosed inventive concepts, a method of disguising captured constituents includes chemically converting the spent reactive sweep gas, i.e. the reactive sweep gas containing the captured constituents that transferred from a stationary or liquid phase by means of another method. The chemical conversion includes premixing the spent reactive sweep gas with either a fuel or an oxidizer as appropriate to enable a stoichiometric or near stoichiometric conversion of reactive sweep gas, and hence converting the reactive constituents of the spent reactive sweep gas to either an oxidized or reduced form. In one approach, the reactive sweep gas is oxygen and thus the said premixing requires addition of fuel that converts the oxygen to water while generating byproduct carbon dioxide. In another approach, the reactive sweep gas is a hydrocarbon fuel and thus the said premixing requires the addition of an oxidizer that converts the fuel to carbon dioxide and water. In one embodiment, the reactive sweep gas is a hydrocarbon fuel; the spent reactive sweep gas is a mixture of hydrocarbon, carbon dioxide, and moisture; and the chemical conversion produces a final gas mixture of carbon dioxide and moisture wherein the carbon dioxide molecules are indistinguishable—i.e., it is impossible to determine whether the origin of their carbon atoms is the fuel or the carbon dioxide in the initial spent reactive sweep gas, at least without isotopic measurement—further, the water molecules are similarly indistinguishable, as they originate at the initial capture or the chemical conversion. The chemical conversion may occur by means of conventional combustion, oxycombustion, pressurized oxycombustion, or a fuel cell operation such as a solid oxide fuel cell.

[0097] FIG. 5A is a schematic diagram that shows the capture unit 1B, which uses an oxygen stream 15 as a reactive sweep stream in order to produce a spent reactive sweep stream 5 that ultimately is combusted. The spent stream 5 is mixed with pipelined natural gas via stream 10 that is reduced to a suitable pressure through valve 19 prior to mixing within the Mixer 16 in a near stoichiometric ratio that enables subsequent combustion in the combustor 17. Effluent gas from the combustor 17 emerges as Stream 18, which primarily consist of carbon dioxide and water. Stream 18 proceeds to a cooling operation where a heat flow Q is removed, leading to an enriched carbon dioxide stream 21 and a liquid water stream 22. The heat flow may be absorbed by air or by cooling water. This configuration is most suited for integration into a pressurized oxycombustion cycle such as the Allam Cycle—such integration is described in greater detail hereafter.

[0098] FIG. 5B is a schematic diagram that shows the capture unit 1B, which uses a methane stream 15 as a reactive sweep stream in order to produce a spent reactive sweep stream 5 that ultimately is converted by reaction in a fuel cell. The spent stream 5 is mixed with pipelined natural gas via stream 10 that is reduced to a suitable pressure through valve 19 prior to mixing within the Mixer 16 in a ratio that enables subsequent reaction at the anode to a methane fuel cell such as a solid oxide fuel cell 23. The anode of fuel cell 23 accepts the hydrocarbon stream 24, which contains the spent reactive sweep gas (methane with captured constituents) and the additional methane of Stream 10. The cathode of fuel cell 23 accepts air from Stream 25. Oxygen depleted air exits as Stream 26. Atomic oxygen migrates across the solid oxide membrane within the fuel cell, and subsequently reacts with the reactive constituents at the anode. Carbon-dioxide and water are enriched at the anode side and they exit as Stream 27, which may contain residual methane depending on the residence time at the anode. In one embodiment, a cooling operation subsequently removes the water of Stream 27. Electricity flows to a resistive load 28. In another embodiment, the methane fuel cell employs a proton transfer membrane, leading to water generation at the cathode side.

[0099] In accordance with yet another aspect of the presently disclosed inventive concepts, a method includes chemically converting a spent reactive sweep gas, wherein hydrogen is the original reactive sweep gas. The chemical conversion includes premixing the said spent gas (a mixture of hydrogen, water, and carbon dioxide) with an oxidizer to enable a stoichiometric or near stoichiometric conversion, hence converting the hydrogen of the spent reactive sweep gas to water, which can be removed to yield a final purified carbon dioxide product stream. In one embodiment, the hydrogen is produced by electrolysis. In another embodiment, the oxidizer is air and therefore the final product stream is nitrogen enriched with carbon dioxide. In one use case, the nitrogen with carbon dioxide product stream is used to support plant growth in a greenhouse.

[0100] In accordance with yet another aspect of the presently disclosed inventive concepts, a method includes chemically converting a spent reactive sweep gas, wherein carbon monoxide is the original reactive sweep gas. The chemical conversion includes premixing the said spent gas (a mixture of carbon monoxide, water, and carbon dioxide) with an oxidizer to enable a stoichiometric or near stoichiometric conversion, hence converting the carbon monoxide of the spent reactive sweep gas to carbon dioxide, yielding a moist carbon dioxide stream that can be dehydrated through condensation. In one embodiment, the carbon monoxide is produced by electrolysis. In another embodiment, the oxidizer is air and therefore the final product stream is nitrogen enriched with carbon dioxide. In one use case, the nitrogen with carbon dioxide product stream is used to support plant growth in a greenhouse.

[0101] In accordance with yet another aspect of the presently disclosed inventive concepts, a method includes chemically converting a spent reactive sweep gas, wherein synthesis gas is the original reactive sweep gas. The chemical conversion includes premixing the said spent gas (a mixture of carbon monoxide, carbon dioxide, water, and hydrogen) with an oxidizer to enable a stoichiometric or near stoichiometric conversion, hence converting the carbon monoxide and hydrogen of the spent reactive sweep gas to carbon dioxide and water, respectively, yielding a moist carbon dioxide stream that can be dehydrated through condensation. In one embodiment, the carbon monoxide is produced by electrolysis. In another embodiment, the oxidizer is air and therefore the final product stream is nitrogen enriched with carbon dioxide. In one use case, the nitrogen with carbon dioxide product stream is used to support plant growth in a greenhouse.

[0102] In accordance with yet another aspect of the presently disclosed inventive concepts, a process for transferring carbon dioxide includes capturing carbon dioxide from a gas phase by means of using a stationary or liquid phase, non-thermally regenerating the stationary or liquid phase by means of contact with a reactive sweep fluid thus forming a spent reactive sweep fluid, chemically converting the spent reactive sweep fluid to carbon dioxide and water in the absence of nitrogen, removing the moisture physically by cooling, and thus yielding an essentially pure carbon dioxide product. The pure carbon dioxide product consists of the initially captured carbon dioxide and the generated carbon dioxide. In another embodiment, the disclosed dynamic pressure adjustment method is included within the process in order to maximize the ratio of captured carbon dioxide to generated carbon dioxide in the final product. In yet another embodiment, the spent reactive sweep fluid is chemically converted by ordinary combustion with air, ultimately yielding a nitrogen stream that is enriched with carbon dioxide, which comprises captured and generated carbon dioxide molecules. In yet another embodiment, the spent reactive sweep fluid is chemically converted at the anode of a fuel cell, as in a solid oxide fuel cell using an anion exchange membrane allowing migration of oxygen atoms from the cathode, which is in contact with air. In one use case, the carbon dioxide is captured from regular air. In another use case, the carbon dioxide is captured from a building's HVAC exhaust. In yet another use case, the carbon dioxide is captured from the flue gas of ordinary combustion. In yet another use case, the carbon dioxide is captured from shifted synthesis gas.

[0103] In accordance with yet another aspect of the presently disclosed inventive concepts, a process of transferring moisture includes capturing moisture from a gas phase by means of using a stationary or liquid phase, non-thermally regenerating the stationary or liquid phase by means of contact with a reactive sweep fluid thus forming a spent reactive sweep fluid, chemically converting the spent reactive sweep fluid to carbon dioxide and water (with or without the presence of nitrogen), and venting the moist gas. In another embodiment, the moist gas is cooled to collect the water and the residual gas is vented. In one use case, the spent reactive sweep gas is combusted with air at a cook stove, while the initial moisture capture serves to dehumidify the incoming air to an air conditioning system. A chemical engineering practitioner would be able to design a condensation system and tank for collecting liquid water, and therefore such a system and unit operation are not illustrated or further described herein.

[0104] In accordance with yet another aspect of the presently disclosed inventive concepts, a method of operation includes capturing constituents from a gas phase by flowing the gas upward over a sorbent such that it attains a fluidized bed or bubbling bed configuration, subsequently directing flow in the downward direction to attain a packed bed configuration, replacing the initial gas phase with a reactive sweep gas that continues to flow downward, and switching the gas phase composition and direction of flow back to the original state to repeat the cycle. In one embodiment, the packed bed configuration attained through downward flow of reactive sweep gas enables the dynamic pressure adjustment method; while the fluidized or bubbling bed configurations enhance the efficiency of gas flow during the initial capture. In another embodiment, the bed configuration remains packed regardless of the sweep gas or direction of flow.

[0105] FIG. 6 is a schematic diagram of a capture unit, i.e. Element 1C, which is enabled for bidirectional gas flow through a stationary phase and for full fluidization. Element 1C is also known as Vessel 1C and it contains a confined stationary phase of sorbent that becomes a fully fluidized bed due to the upward flow of inlet gas stream 2 as well as the changing diameter of Vessel 1C. Stream 2 delivers an initial gas containing targeted constituents to the stationary phase, and Stream 3 removes a gas that is leaner in targeted constituents until the stationary phase becomes saturated and the composition of Streams 2 and 3 become identical. After that time, Streams 2 and 3 are closed using valves (not shown), and then Streams 4 and 5 are opened to allow the flow of reactive sweep gas in the downward direction. The transition from upward flow to downward flow reduces the macro-scale porosity of the stationary phase, creating more resistance to flow and thereby increasing the pressure drop across the stationary phase. Three-way valve 20 assists gas switching when the gas flow reverses.

[0106] When the inventive concepts disclosed herein are applied to the removal of carbon dioxide from air, the system or systems are referred to as DAC systems or Post-Emission Capture (PEC) systems interchangeably herein. Further, the term Allam cycle is used generally to include oxygen fueled cycles including the Allam-Fetvedt cycle.

[0107] Allam Cycle Integration

[0108] FIG. 100 is a simplified block flow diagram of a gas-fed Allam Cycle. Natural Gas (NG) stream 113 flows to the combustor 102, where it burned in a mixture of oxygen (O.sub.2) and carbon dioxide (CO.sub.2). The combustor 102 receives the CO2-rich stream 122 through recycling from downstream within this process. An Air Separation Unit (ASU) 101 produces the oxygen-rich stream 111 for combustor 102, and the nitrogen-rich stream 112, from the initial Air stream 110.

[0109] The combustor 102 delivers the high-temperature combustion mixture 114 that is used to spin the expander 103 and thus produce power through the generator 104. The effluent gas stream 115 from the expander 103 exchanges heat with the produced CO2 stream 121 by means of the heat exchanger 105. The cooler effluent gas stream 116 is cooled further by the chiller 106 in order to condense and separate moisture via the separator 107. CO2-rich product stream 119 is pumped for delivery and for recycling via the CO2-recycle stream 121.

[0110] Optionally, alternative systems for oxygen production exist and may become more advantageous than the ASU system 101, including but not limited to systems that employ the electrolysis of water or the electrochemical reduction of CO2.

[0111] Optionally, a fraction of the CO2-rich stream 122 could be relayed to the expander 103 rather than to the combustor 102.

[0112] Optionally, NG stream 113 may come from a biogenic source, a natural gas pipeline, or a source of methane hydrates. The pressure of NG is in the range of 1 atmosphere to hundreds of atmospheres, depending on the source.

[0113] FIG. 130 is a simplified block flow diagram of a gas-fed Allam Cycle that is modified by the addition of Post-Emission Capture (PEC) system 130. The PEC system 130 executes the aforementioned capture and regeneration methods that employ reactive sweep gases.

[0114] As illustrated, all of the NG stream 113 and oxygen stream 132 are diverted to PEC system 130. In other embodiments, a slip stream of 113 and 132 may be diverted to 130. In a highly preferred embodiment, the PEC system receives air and oxygen only, and it delivers a final mixture of CO2-O2 at a pressure sufficient to insert into the CO2 recycle stream 122 that is relayed to the combustor 102 and requires a compressor (not shown).

[0115] Air stream 131 is diverted to PEC system 130. In another embodiment, an independent air stream may be used. In other embodiments, a dehydrated air stream may be used as stream 131. Yet in other embodiments, dry air from the ASU 101 may be diverted to 130.

[0116] The fans that create airflow for the ASU system 101 are included within 101 and are responsible for the flow of air stream 110 without effect on 131. In another embodiment, air in stream 131 is pulled into 130 by natural convection that is driven downstream. Optionally, fans may be used to assist air flow in stream 131, which will otherwise be driven by the natural convection that is created within the PEC system 130 as described herein.

[0117] The natural gas feed (NGF) stream 133 and the oxygen feed (OF) stream 134 for the combustor 102 are produced by the PEC system 130. The vent stream 135 returns air to the environment.

[0118] FIG. 135 is a simplified block flow diagram of a modified gas-fed Allam Cycle that is further modified by the addition of PEC system 130 in a highly preferred embodiment. The PEC system receives air stream 2000 and oxygen stream 2001, and it delivers a CO2-O2 stream 2003 at a pressure sufficient to insert into the CO2 recycle stream 122 that is relayed as stream 2004 to the combustor 102. This requires at least one compressor (not shown). The PEC system emits an air stream 2002 that is depleted in CO2. In the most preferred embodiments (for gas-fed and coal-fed Allam cycles), the PEC system receives air and oxygen only and delivers a CO2-O2 stream for insertion into one of the following streams: 122 (as illustrated), 111 (oxygen), 113 (fuel).

[0119] FIG. 140 is a simplified block flow diagram of a modified gas-fed Allam Cycle that is further modified by the addition of PEC system 130. The Allam cycle is modified by replacing the ASU system with the electrolyzer system 140, which produces the oxygen-rich stream 132 and the hydrogen-rich stream 141. Optionally, other oxygen production systems may be employed in lieu of system 140. For example, oxygen may be derived from a CO.sub.2 reduction system that produces carbon monoxide (CO) and oxygen.

[0120] FIG. 150 is a simplified block flow diagram of a modified gas-fed Allam Cycle that is further modified by the addition of an alternative PEC system 130 that accepts a hydrocarbon (HC) inlet stream 223 and that produces a hydrocarbon feed (HCF) stream 233 for the combustor 102. Combustor 102 receives NG stream 113 directly, as in the original gas-fired Allam Cycle process illustrated in FIG. 100. The HC of stream 223 may be in the gas phase, the liquid phase, or a mixed phase.

[0121] FIG. 160 is a simplified block flow diagram of a modified gas-fed Allam Cycle that is further modified by the addition of an alternative PEC system 130 that accepts the hydrocarbon (HC) stream 210 into the NG stream 113. The HC of stream 210 may be injected periodically into 113 or it may be co-fed steadily with 113. The HC of stream 210 may be in the gas phase, the liquid phase, or a mixed phase.

[0122] FIG. 170 is a simplified block flow diagram of a portion of the coal-fed Allam Cycle. Coal-derived dry compressed Syngas (SG) stream 170 flows to the combustor 102, where it burned in a mixture of oxygen (O.sub.2) and carbon dioxide (CO.sub.2). The SG stream 170 consists mainly of carbon monoxide (CO) and hydrogen (H.sub.2). The combustor 102 receives the CO2-rich stream 122 through recycling from downstream within this process. An Air Separation Unit (ASU) 101 produces the oxygen-rich stream 111 for combustor 102, and the nitrogen-rich stream 112, from the initial Air stream 110.

[0123] FIG. 175 is a simplified block flow diagram of a portion of a coal-fed Allam Cycle that is modified by the addition of Post-Emission Capture (PEC) system 130. As illustrated, all of the SG stream 170 and oxygen stream 132 are diverted to PEC system 130. In other embodiments a slip stream of 170 and 132 may be diverted to 130.

[0124] Air stream 131 is diverted to PEC system 130. The fans that create airflow for the ASU system 101 are included within 101 and are responsible for the flow of air stream 110 without effect on 131. The syngas feed (SGF) stream 173 and the oxygen feed (OF) stream 134 for the combustor 102 are produced by the PEC system 130. The vent stream 135 returns air to the environment.

[0125] Optionally, fans may be used to assist air flow in stream 131, which will otherwise be driven by the natural convection that is created within the PEC system 130 as described herein.

[0126] FIG. 180 is a simplified block flow diagram of a portion of a modified coal-fed Allam Cycle that is further modified by the addition of PEC system 130. The Allam cycle is modified by replacing the ASU system with the electrolyzer system 140, which produces the oxygen-rich stream 132 and the hydrogen-rich stream 141. Optionally, other oxygen production systems may be employed in lieu of system 140.

[0127] FIG. 185 is a simplified block flow diagram of a portion of a modified coal-fed Allam Cycle that is further modified by the addition of an alternative PEC system 130 that accepts a hydrocarbon (HC) inlet stream 223 and that produces a hydrocarbon feed (HCF) stream 233 for the combustor 102. Combustor 102 receives SG stream 170 directly, as in the original coal-fired Allam Cycle process partially illustrated in FIG. 170. The HC stream 223 may be a liquid phase, gas phase, or mixed phase.

[0128] FIG. 190 is a simplified block flow diagram of a portion of a modified coal-fed Allam Cycle that is further modified by the addition of an alternative PEC system 130 that accepts the hydrocarbon (HC) stream 210 into the SG stream 170. The HC of stream 210 may be injected periodically into 170 or it may be co-fed steadily with 170. The HC stream 210 may be a liquid phase, gas phase, or mixed phase.

[0129] FIG. 195 is a simplified block flow diagram of a portion of a modified coal-fed Allam Cycle that is further modified by the addition of an alternative PEC system 130 in a highly preferred embodiment. The PEC system receives air stream 2000 and oxygen stream 2001, and it delivers a CO2-O2 stream 2003 at a pressure sufficient to insert into the CO2 recycle stream 122 that is relayed as stream 2004 to the combustor 102. This requires at least one compressor (not shown). The PEC system emits an air stream 2002 that is depleted in CO2. In the most preferred embodiments (for gas-fed and coal-fed Allam cycles), the PEC system receives air and oxygen only and delivers a CO2-O2 stream for insertion into one of the following streams: 122 (as illustrated), 111 (oxygen), 170 (fuel).

[0130] FIG. 200 illustrates the inputs to and subsystems of PEC system 130 which accepts fuel. In preferred embodiments, the fuel streams 113 and 133 are absent. A switching valve 200 is customized to direct one of the input streams (113, 131, 132) toward the capture subsystem 202—the selected input stream is relayed toward subsystem 202 via stream 201. Stream 203 emerges from capture subsystem 202 and is directed by switching valve 204 to one of the exit streams (133, 134, 135). Other embodiments may have a different number of input streams or exit streams. An alternative preferred configuration is shown in FIG. 2200.

[0131] The input streams (113, 131, 132) and the exit streams (133, 134, 135) alternate by means of adjusting switching valves 200 and 204. The adjustment of switching valves is not necessarily executed in phase with respect to time, as described here.

[0132] First, in the original state, the Air stream 131 is directed to pass through subsystem 202 and to exit via the Vent stream 135. Generally, in this configuration, the carbon dioxide (CO2) within the air is being sorbed within 202. (However, the sorption of CO2 is enhanced by pressurized NG in the next step—this is described in more detail in a subsequent section.)

[0133] Second, the NG stream 113 is directed to pass through subsystem 202, cutting off the Air stream 131. Stream 203 continues to be directed to exit via the Vent stream 135 until NG breakthrough is detected at or in the vicinity of switching valve 204 (hereafter curtailed as “at 204”). The gas detector (not illustrated) can be a thermal conductivity detector or another gas detection approach. When NG breakthrough is detected at 204, stream 203 is directed to exit via the NGF stream 133. Generally, in this configuration, the NG first enhances the CO2 sorption (by elevating the pressure at 202) and then it drives CO2 off of the sorbent phase (solid, fluid, or polymer) in subsystem 202 via cosorption phenomena.

[0134] Third, the oxygen stream 132 is directed to pass through subsystem 202, cutting off the NG stream 113. Stream 203 continues to be directed to exit via the NGF stream 133 until oxygen breakthrough is detected at 204. When oxygen breakthrough is detected at 204, stream 203 is directed to exit via the oxygen feed (OF) stream 134. Generally, in this configuration, oxygen eliminates any residual NG in the PEC system 130 to prevent any subsequent emission of greenhouse gas via the Vent stream 135.

[0135] To return the system to its original state, the Air stream 131 is directed to pass through subsystem 202, cutting off the oxygen stream 132. Stream 203 continues to be directed to exit via the OF stream 134 until air breakthrough is detected at 204. When air breakthrough is detected at 204, stream 203 is directed to exit via the Vent stream 135. This is the original state.

[0136] FIG. 210 illustrates the inputs to and subsystems of PEC system 130, with a modified operating procedure than that described in association with FIG. 200. In this approach, a hydrocarbon (HC) pulse is injected into the NG stream 113 by means of HC stream 210. The HC may be a liquid or a gas.

[0137] In one embodiment, liquid HC serves to limit turbulent mixing of NG and Air. In another embodiment, HC assists desorption within subsystem 202, as a liquid or after a phase change to a gas. In another embodiment, liquid or gaseous HC serves to assist heat transfer phenomena that occurs within system 130 upon switching from using Air stream 131 to NG stream 113 by means of adjusting valve 200. Yet in another embodiment, HC stream 210 may consist of pulses of two or more different HC constituents that exhibit different phase behavior and thermal properties.

[0138] In another embodiment, the HC pulse is injected through a chromatographic switching valve typically used for injections.

[0139] FIG. 220 illustrates the inputs to and subsystems of PEC system 130, with a modified sequence of constituents introduced into system 130. In this approach, a hydrocarbon (HC) stream 223 completely substitutes the natural gas (NG) or syngas (SG) streams used in other embodiments. In one embodiment, the HC stream 223 may consist of NG or SG and other constituents. This Figure is associated with FIG. 150 or FIG. 185.

[0140] FIG. 230 illustrates the inputs to and subsystems of PEC system 130. Syngas (SG) stream 170 replaces the NG stream 113 in FIG. 200. The general operating procedure is the same as described in association with FIG. 200, substituting SG for NG and SGF for NGF.

[0141] FIG. 240 illustrates the inputs to and subsystems of PEC system 130, with a modified operating procedure. In this approach, a hydrocarbon (HC) pulse is injected into the SG stream 170 by means of HC stream 210. The HC may be a liquid or a gas. Generally, the operating procedure is the same as that described with FIGS. 200 and 210, substituting SG for NG and SGF for NGF.

[0142] FIG. 300 illustrates an arrangement of subunits for a basic subsystem 202. Metering valves 300 and 304 enable precise flow and pressure control that is essential to switching among operational states. The primary CO2 capture unit resides within subunit 302. Streams 201 and 203 are referenced in other Figures.

[0143] FIG. 310 illustrates an arrangement of subunits for a subsystem 202 that employs a separate dehydration step. Subunit 310 is designed to selectively dehydrate stream 201 so that carbon dioxide is preferentially sorbed within subunit 302. This approach may become most suitable for cases wherein moisture and CO2 sorb too competitively within subunit 302.

[0144] FIG. 320 illustrates an arrangement of subunits for a subsystem 202 that employs a separate dehydration step. Subunit 320 is designed to selectively dehydrate stream 201 so that carbon dioxide is preferentially sorbed within subunit 302. The dehydration would occur by opening valve 321 and closing valve 300, ensuring pressure driven flow of stream 201 toward subunit 320. After dehydration, flow toward subunit 302 would resume by closing valve 323 and opening valve 300.

[0145] This approach may become most suitable for cases wherein moisture and CO2 sorb too competitively within subunit 302, when an in-line desiccant creates too much pressure drop, or when alternative methods of moisture removal are sought.

[0146] In another embodiment, subunit 320 may be connected to a Vent stream (e.g. 135) to enable regeneration of the desiccant in subunit 320 without relaying moisture through subunit 302.

[0147] FIG. 330 illustrates a parallel arrangement of subsystems 202 that would enable reduction of pressure loss (pressure gradient) across each subsystem. Sub-systems 202(i), 202(ii), and 202(iii) are independent and presented as examples—any number of parallel subsystems may be employed.

[0148] FIG. 400 illustrates one embodiment of a capture subunit 302. Element 400 is a chromatography column (or analog) that consists of a stationary phase adhering to the inner walls of the column. The stationary phase may be polymeric, a solid, or a mixed phase.

[0149] FIG. 410 illustrates another embodiment of a capture subunit 302. Element 410 is a column that consists of a confined stationary phase. The stationary phase may be a packed bed consisting of one or more sorbent materials.

[0150] FIG. 420 illustrates another embodiment of a capture subunit 302. Element 420 is a vessel that consists of a confined stationary phase. The stationary phase may be a packed bed consisting of one or more sorbent materials. The bed may operate in a stationary or a bubbling mode. Vessel 420 and Vessel 1 in FIG. 1A are equivalent.

[0151] FIG. 430 illustrates another embodiment of a capture subunit 302. Element 430 is a vessel suitable for fluidized bed operation. The bed may consisting of one or more sorbent materials. Optionally, a filter or a hydrocyclone with recycle stream may be inserted between 430 and stream 303 in order to capture any fine solids that escape 430 during fluidized bed operation.

[0152] FIG. 440 illustrates another embodiment of a capture subsystem 302. Element 440 is a vessel that contains a liquid or polymer solution that preferentially sorbs carbon dioxide. Stream 441 loads fluid into element 440, and stream 442 drains fluid from 440. Loading or draining may occur periodically or continuously. Stream 443 provides inert gas for padding the vessel and for general pressure management.

[0153] FIG. 500 illustrates an arrangement of subunits for a subsystem 202 that employs a pressure and thermal management method. The method enhances the sorption of carbon dioxide in subunit 302.

[0154] Valve 300 closes, isolating subunit 302. Upon introducing pressurized NG (or HC or SG) through the switching valve 200, a pressure pulse propagates at the speed of sound downstream of 200 until valve 300. NG begins to enter through stream 201, filling section 501 and applying pressure to the air originally in sections 501, 502, 503, and 504. The original air compresses until its pressure equals that of the incoming NG, and this causes the flow to stop—the incoming NG pressure decreases when NG is injected as a pulse, but it remains at its original pressure otherwise. The air heats significantly during this compression. Once the air upstream of valve 300 has cooled down, valve 300 opens to establish air flow into subunit 302, which adsorbs carbon dioxide at an elevated partial pressure. Once subunit 302 cools to original temperature and CO2 sorption stops, valve 304 opens to establish flow. NG that followed the compressed air desorbs the CO2 in subunit 302 while pushing the CO2-lean air out through stream 203.

[0155] Subunit 500 has a shell and tube design. Section 503 is straight and has a high surface-to-volume ratio that enhances heat transfer between the contents of 503 and the space 502. As illustrated, stream 501 enters at the same end of 500 that stream 503 exits. This compels the gas flow entering 500 via 501 to flow across the outer surface of 503 before entering the inner volume of 503.

[0156] In one embodiment, the pressure of air is elevated to 30- to 350-atmospheres due to NG supply at equal or greater pressure. If the air was compressed to 100-atmosphere, this effect enhances the sorption of CO2 because the fugacity of CO2 increases with total pressure—the air appears to contain 4% CO2 by volume instead of 0.04% (i.e. 400 ppm).

[0157] In one embodiment, the heat generated due to air compression in subunit 302 is salvaged by heat exchange with the air that exits through Vent 135 on a parallel identical system. This enhances a natural convection drive in the parallel system. In another embodiment, the hot compressed air becomes confined mostly to sections 503 and 504, and its is used to preheat the NG that filled section 502.

[0158] In another embodiment, valves 300 and 304 are opened simultaneously to establish flow at higher average pressure in subunit 302.

[0159] In another embodiment, valve 300 is opened and valve 304 is closed during the compression of air that occurs with NG introduction. The associated heating regenerates the capture subunit 302, whose void (gas) volume is then purged by opening valve 304. Valve 304 is closed again after the purge, allowing carbon dioxide to sorb within subunit 302 as the air temperature decreases to its original temperature.

[0160] In one embodiment, the NG desorbs both carbon dioxide and moisture from 302, carrying both downstream to stream 203. In another embodiment, moisture is captured by a separate desiccant and purged using hot compressed air.

[0161] In another embodiment, a pulse of hydrocarbon (HC) liquid precedes the NG in stream 201 in order to minimize turbulent mixing in section 501.

[0162] In another embodiment, the HC liquid evaporates within subunit 500 by receiving the heat of air compression—this limits the temperature rise or air. FIGS. 160 and 210 illustrate exemplary systems wherein HC co-feed is used.

[0163] FIG. 510 illustrates an arrangement of subunits for a subsystem 202 that employs an alternative pressure and thermal management method. The method enhances the sorption of carbon dioxide in subunit 302.

[0164] Valve 300 closes, isolating subunit 302. Upon introducing pressurized NG (or HC or SG) through the switching valve 200, a pressure pulse propagates at the speed of sound downstream of 200 until valve 300. NG begins to enter through stream 201, filling section 509 and applying pressure to the air originally in sections 509, 511, 512, and 513. The original air compresses until its pressure equals that of the incoming NG, and this causes the flow to stop—the incoming NG pressure decreases when NG is injected as a pulse, but it remains at its original pressure otherwise. The air heats significantly during this compression. Once the air upstream of valve 300 has cooled down, valve 300 opens to establish air flow into subunit 302, which adsorbs carbon dioxide at an elevated partial pressure. Once subunit 302 cools to original temperature and CO2 sorption stops, valve 304 opens to establish flow. NG that followed the compressed air desorbs the CO2 in subunit 302 while pushing the CO2-lean air out through stream 203.

[0165] In one embodiment, the hot compressed air becomes confined mostly to sections 512 and 513, and its is used in part to preheat the NG in section 511, and in part to heat the surroundings through the heat exchange surface of subunit 510. In another embodiment, the hot compressed air heats the air exiting a parallel identical system, as illustrated in FIG. 520.

[0166] In another embodiment, a pulse of hydrocarbon (HC) liquid precedes the NG in stream 201 in order to minimize turbulent mixing in section 509 and beyond. In another embodiment, the HC liquid evaporates within section 509 and absorbs in part the heat of air compression—this limits the temperature rise of air. FIGS. 160 and 210 illustrate exemplary systems wherein HC co-feed is used.

[0167] FIG. 520 illustrates an arrangement of subunits for a subsystem 202 that employs an alternative pressure and thermal management method described in association with FIG. 510. This method is used to transfer heat from hot compressed air across the surface of subunit 510, to air that is being vented from a parallel identical system. This approach enhances the natural convection potential in the parallel system.

[0168] FIG. 550 illustrates the arrangement of parallel systems that utilize the method described in association with FIG. 520 for the purpose of providing natural convection drive.

[0169] Air in stream 131 is being pulled through subsystem 130 of system (I), which is in configuration (a). This configuration consists of the operating state before NG (or HC or SG) is introduced. Heat exchanger 550 is used to provide an amount of heat Q to stream 135. Chimney 551 is used to establish the natural convection. Air vents to atmosphere at a higher elevation.

[0170] The amount of heat Q is provided from subsystem 130 of system (II), which is in configuration (b). This configuration consists of the operating state after NG (or HC or SG) is introduced, leading to the compression of air and associated temperature rise.

[0171] In another embodiment, Q-driven convection may be supplemented or replaced by upstream blowers or otherwise attained pressure from upstream air.

[0172] FIG. 560 illustrates the use of a heat pipe for the purpose of transferring heat from system (II) to system (I), in accordance with FIG. 550. The heat pipe consists of an evaporator 560 and a condenser 561. Vapor stream 563 flows up from the evaporator, and condensate stream 562 flows down from the condenser.

[0173] FIG. 900 is a simplified block flow diagram of an alternative Post-Emission Capture (PEC) process that is suitable for a CCS-enabled power plant 932. The power plant may be a gas or a coal fired plant. Hydrocarbon (HC) stream 913 and Air stream 931 are directed to the PEC system 930. The PEC system 930 produces Vent stream 935, hydrocarbon feed (HCF) stream 933, and combustion air (CA) stream 934. The power plant 932 produces a CO2-lean flue gas 936 and a CO2 product stream 937. The HCF stream 933 would be co-fired with the fuel for plant 932.

[0174] FIG. 910 illustrates the inputs to and subsystems of PEC system 930, which is associated with FIG. 900. The HC stream 913 may be a gas or liquid.

[0175] A switching valve 200 is customized to direct one of two input streams (913, 931) toward the capture subsystem 202—the selected input stream is relayed toward subsystem 202 via stream 201. Stream 203 emerges from capture subsystem 202 and is directed by switching valve 204 to one of three exit streams (933, 934, 935). Other embodiments may have a different number of input streams or exit streams.

[0176] First, the Air stream 931 is directed to pass through subsystem 202 and to exit via the Vent stream 935. Generally, in this configuration, the carbon dioxide (CO2) within the air is being sorbed (adsorbed or absorbed) within 202.

[0177] Second, the HC stream 913 is directed to pass through subsystem 202, cutting off the Air stream 931. Stream 203 continues to be directed to exit via the Vent stream 135 until HC breakthrough is detected at or in the vicinity of switching valve 204 (hereafter curtailed as “at 204”). When HC breakthrough is detected at 204, stream 203 is directed to exit via the HCF stream 933. Generally, in this configuration, the NG drives CO2 off of the sorbent phase (solid, fluid, or polymer) in subsystem 202 via cosorption phenomena.

[0178] Third, the air stream 931 is directed to pass through subsystem 202, cutting off the HC stream 913. Stream 203 continues to be directed to exit via the HCF stream 933 until air breakthrough is detected at 204. When air breakthrough is detected at 204, stream 203 is directed to exit via the combustion air (CA) stream 934. Generally, in this configuration, air eliminates any residual HC in the PEC system 930 to prevent any subsequent emissions via the Vent stream 935. After the system 930 has been purged with air, stream 203 is directed to exit via the Vent stream 935.

[0179] FIG. 1000 is a simplified block flow diagram for a conventional solvent-based carbon dioxide capture process, e.g. a process that uses mono-ethanol amine (MEA). A power plant's flue gas stream 1003 is received by absorber 1001, which emits a lean flue gas in stream 1004. Absorber 1001 receives lean solvent stream 1007 from the regenerator 1002, and it gives a CO2-rich solvent stream 1006 to regenerator 1002. A CO2 rich vapor stream 1005 exits 1002 and is relayed downstream for further processing such as compression or CO2 conversion. Pumps, reboilers/condensers, heat exchangers, and other equipment exist but are not shown.

[0180] FIG. 1010 is a simplified block flow diagram for a modified solvent-based carbon dioxide capture process, wherein natural gas (NG) stream 1011 is used to desorb CO2 from the regenerator 1010. Regenerator 1010 produces natural gas feed (NGF) stream 1012 for combustion in a CCS enabled process, and it produces CO2-lean capture solvent 1014 for use in the absorber 1001. CO2-rich solvent stream 1013 flows to the regenerator 1010. Both 1001 and 1010 are liquid-gas contactors.

[0181] In one embodiment, NG is replaced with a different hydrocarbon gas that is ultimately combusted in a separate CCS-enabled process.

[0182] In another embodiment, the NGF stream 1012 takes part in the combustion that produces flue gas stream 1003.

[0183] FIG. 1020 is a simplified block flow diagram for a modified solvent-based carbon dioxide capture process, wherein natural gas (NG) stream 1011 is used to partially desorb CO2 from a primary regenerator 1010. Regenerator 1010 produces natural gas feed (NGF) stream 1012 for combustion in a CCS enabled process, and it produces leaner capture solvent 1020 for further regeneration in a conventional regenerator 1002 that is equipped with a reboiler (not shown). The secondary regenerator 1002 produces an even leaner capture solvent for use in the absorber 1001. Both 1001 and 1010 are liquid-gas contactors. Regenerator 1002 includes a reboiler that requires heat input.

[0184] In one embodiment, NG is replaced with a different hydrocarbon gas that is ultimately combusted in a separate CCS-enabled process.

[0185] In another embodiment, the NGF stream 1012 takes part in the combustion that produces flue gas stream 1003.

[0186] FIG. 2100 is a schematic that illustrates the possibilities for and logic of reactive disguisement. Consider volume 2101 of gas comprising two components (A and B) that need to be separated and where component A is the desired product. The desired outcome is attainment of a volume of gas 2103 that contains component A but not component B. In lieu of an extensive number of physical separation stages with significant energy inputs for regeneration, a reactive disguisement approach 2102 may be taken to chemically convert component B into component A. This is what occurs in Pruet's thermal oxidizer wherein A=H2O and B=H2 (vide supra, US 2005/0284290A1). Unfortunately, this approach (2102) is not possible for DAC or DACPGS processes because the components are A=CO2 and B=N2, and N2 cannot be converted to CO2.

[0187] An alternative approach 2104 involves replacing B with another component C, much like the invention of Keefer et al. (vide supra, US 2004/0011198A1), to attain a volume of gas 2105 comprising A and C; and subsequently converting C to A by means of 2106 to attain a volume of gas 2107 that contains component A but not component B. Unfortunately, this approach is not possible for DACPGS when the components are A=CO2 and C=O2 because O2 does not convert to CO2.

[0188] An alternative approach 2108 adds carbon (K) to attain a system 2109 comprising A, C, and K. This allows for conversion 2110 wherein C and K react to form A. The coal-fed Allam cycle configuration with a PEC operation as illustrated in FIG. 195 is one such example wherein a volume of air (2101) is transformed sequentially by steps 2104, 2108, and 2110 (water is not illustrated).

[0189] In another preferred embodiment that is consistent with the gas-fed DACPGS configuration in FIG. 135, the volume of air (2101) is modified to exchange N2 (component B) for O2 (component C) by means of step 2112 such that the concentration of CO2 (component A) is 33% with the balance being O2 as represented by 2113. The volume 2113 is further modified by introducing methane (G) through 2114 to create a volume 2115 comprising CO2, O2, and CH4. The stoichiometric combustion of gas in oxygen through step 2116 yields a gaseous mixture 2117 comprising CO2 and H2O (W). The mixture 2117 is easily separated by cooling step 2118, which yields two phases: a gas 2119 that is rich in CO2 and a liquid 2120 that is rich in H2O. Collectively, steps 2112, 2114, 2116, and 2118 are the sequence of steps in the DACPGS configuration that is subject of FIG. 135. For example, mixture 2113 represents the mixture in stream 2003; and system 2121 represents the contents of stream 117.

[0190] FIG. 2200 is a block flow diagram that illustrates an adsorbent-based DAC system with four stages 2201, 2202, 2203, and 2204. The flows into and out of the system 130 are consistent with the DACPGS configuration in FIG. 135. These stages exchange mass flows with each other in an alternating sequence as described in association with FIG. 2250. Heat exchangers (not shown) provide interstage heating and cooling.

[0191] FIG. 2250 is a schematic that shows the sequence of exchanges among the four stages of the adsorbent-based DAC system. The system cycles between configuration A and configuration B. In configuration A, the first adsorbent stage 2201 is loading with CO2 from the air stream 2000; the fourth adsorbent stage 2204 is unloading its CO2 by means of contact with oxygen 2001 at an elevated temperature; and the central two stages are transferring CO2 from the second stage 2202 to the third stage 2203. Heat exchangers for heating and cooling are noted on the schematic. In configuration B, the first adsorbent stage 2201 is transferring the captured CO2 to the second stage 2202; and the third adsorbent stage 2203 is transferring CO2 to the fourth adsorbent stage 2204.

[0192] In one embodiment, Zeolite HY HSZ-320 with Si/Al ratio of 5 is the adsorbent for each stage. The parameters of the dual-site Langmuir isotherm for CO2 are: M.sub.1=0.615 mmol/g, b.sub.1=4.04E-9 kPa.sup.−1, Q.sub.1=44.222 kJ/mol, M.sub.2=6.733 mmol/g, b.sub.2=4.036E-7 kPa.sup.−1 and Q2=23.588 kJ/mol. The functioning system has the following tabulated characteristics upon cycling between 300K (CO2 loading) and 343K (CO2 unloading); and a pressure of 100 kPa throughout.

TABLE-US-00001 Stage or Mass Sorbent Reduced Flow Temp* CO2 Fraction Stream [kg] [m3/unit time] [K] [mol/mol] Stage 2201 1,020 Stage 2202 102 Stage 2203 9.62 Stage 2204 4.49 2000 80.7 300 0.000400 2001 0.00209 343 0 2002 80.7 300 0.000393 2003 0.00209 343 0.330 2011 6.49 300 0.00258 2012 7.42 343 0.00248 2013 0.559 300 0.0160 2014 0.639 343 0.0149 2015 0.0341 300 0.0880 2016 0.0390 343 0.0703 *Temperature is reported downstream of the heat exchanger.

[0193] The inventive concepts disclosed herein have been presented by way of example to illustrate the features thereof in a plurality of illustrative scenarios, embodiments, and/or implementations. It should be appreciated that the concepts generally disclosed may be implemented in any combination, permutation, or synthesis thereof. In addition, any modification, alteration, or equivalent of the presently disclosed features, functions, and concepts that would be appreciated by a person having ordinary skill in the art upon reading the instant descriptions should also be considered within the scope of this disclosure.

[0194] While inventive concepts have been described above, they have been presented by way of example only, and not limitation. Thus, the breadth and scope of the various aspects of the present invention should not be limited by any of the above-described exemplary approaches but should be defined only in accordance with the following claims and their equivalents.