Patent ID: 12226729

DETAILED DESCRIPTION

A significant portion of greenhouse gas emissions comes from carbon dioxide that is released into the atmosphere from numerous sources, including from HVAC systems, refrigeration systems, and industrial processes; land changes (e.g., deforestation); and burning fossil fuels, which can contribute to issues related to climate change. Often emissions are moved through cooling towers. Reducing carbon dioxide in the atmosphere is a priority across many governments and industries. One way to reduce carbon dioxide emissions is to avoid emissions altogether, but complete elimination of emissions is often impossible, impractical, or requires significant modifications and/or capital improvements to modify existing systems and processes.

Another way to reduce carbon dioxide in the atmosphere is removing carbon dioxide from emissions from various sources described above, for example by capturing carbon dioxide from emissions or from the air or from cooling towers moving air. However, there are several challenges related to capturing carbon dioxide, and existing systems are often difficult to implement at large scale.

For example, existing systems may be complicated systems with multiple components spread across different portions of the system. Such a system often needs significant modifications and/or capital improvements to implement carbon capture systems. Moreover, some retrofit carbon dioxide capture systems can interfere with the normal performance of equipment to which they are added, either as a result of the upfront modification or due to the limited capacity or efficiency of existing carbon dioxide capturing systems. Lastly, existing systems often use significant amounts of raw materials, fresh water, and energy, which can counteract the targeted environmental benefits.

Embodiments disclosed herein overcome these and other challenges by providing—among other benefits—systems and methods for capturing carbon dioxide at the point of emission or from the atmosphere that can be efficiently integrated into existing industrial equipment. Moreover, embodiments disclosed herein can not only remove carbon dioxide from a fluid stream but also adsorb the carbon dioxide for later regeneration and eventually sequestration. In some embodiments, a system (e.g., system10) integrates carbon dioxide separation and collection. In some embodiments, the system can be easily integrated into existing systems (e.g., cooling towers), which can reduce capital cost and installation time. In some embodiments, the system is modular. Modularity can allow the system to be built quickly, make the system easily adaptable to different site conditions, allow for rapid scaling up and scaling down, and lower the cost for packaging and shipping. Moreover, systems disclosed herein can integrate with systems, such as cooling towers, without significantly impacting performance of the systems.

FIG.1illustrates a flow chart for a carbon dioxide capturing system (e.g., system10) according to some embodiments. In some embodiments, system10includes fluid source100, reactor200having contactor mode202and regenerator mode204, and power source600.

In some embodiments, fluid source100provides fluid102to reactor200through inlet stream101. In some embodiments, fluid102includes a greenhouse gas (e.g., carbon dioxide). Although system10is described throughout as removing carbon dioxide from a fluid, it is to be understood that system10could be used to remove other gases or contaminants, such as other greenhouse gases. In some embodiments, fluid102is ambient air. In some embodiments, ambient air is non-polluted air processed by sources such as HVAC systems and refrigeration systems. In some embodiments, fluid102includes polluted air. In some embodiments, polluted air is air containing elevated levels of hazardous or toxic components, such as particulate matter or volatile organic compounds. In some embodiments, fluid source100includes a cooling tower and fluid102is the emissions from the cooling tower. In some embodiments, fluid source100is fluid to be passed through a cooling tower. In some embodiments, fluid102can be a gas other than air. In some embodiments, fluid102can be a mixture of different gasses. In some embodiments, system10can be integrated into existing systems, such as cooling towers (e.g., cooling tower800). Cooling towers already flow large amounts of fluid, for example air, so integrating system10into cooling towers reduces energy consumption and land use. However, it is to be understood that some embodiments can also be integrated into other industrial systems and equipment, such as a point of emission in a power plant.

In some embodiments, system10includes reactor200. In some embodiments, reactor200can be an integral reactor that can perform different stages of the carbon dioxide capturing process, such as adsorption and regeneration. This can reduce the total size requirements for the carbon dioxide capturing system and make it readily compatible with various industrial equipment. In some embodiments, as discussed in more detail below, reactor200can operate continuously by having multiple chambers to simultaneously perform adsorption and regeneration. This can increase the efficiency of the capturing process. In some embodiments, the assembly is designed to minimize the pressure drop or velocity change of the air flowing through reactor200, thereby minimizing the interference with a normal operation of the equipment in which system10can be integrated. In some embodiments, as discussed in detail below, reactor200can include a solid monolith for adsorption. In some embodiments, as discussed in detail below, reactor200uses an energy efficient regeneration process.

In some embodiments, reactor200includes one or more contactors202and one or more regenerators204disposed within reactor200. In some embodiments, contactor202and regenerator204are separate structures within reactor200, and in some embodiments, contactor202and regenerator204make an integral structure within reactor200. In some embodiments, reactor200can include inlet stream101, first product stream103, and second product stream105. In some embodiments, reactor200includes one or more monoliths212. In some embodiments, monolith212is an activated carbon monolith impregnated with a sorbent material (e.g., sorbent214). In some embodiments, sorbent214can adsorb carbon dioxide. In some embodiments, fluid102from fluid source100can flow into reactor200through inlet stream101and contact monolith212. In some embodiments, when fluid102contacts monolith212, monolith212can adsorb carbon dioxide from fluid102, and the remaining fluid104(e.g., fluid102less carbon dioxide) exits reactor200through first product stream103.

Reactor200can include an array of monoliths (e.g., array210of monoliths212), as shown inFIGS.3and6-8. Array210can include a grid pattern of monoliths212. As shown inFIG.3, array210can include multiple rows of monoliths212in series with electrodes220between each row of monoliths212. Each row of monoliths212can be arranged in parallel to each other, as shown inFIG.4. In some embodiments, array210is an array having dimensions a×b, where a is an integer from 1 to 250 and b is an integer from 1 to 250. In some embodiments, array210can have between 100 monoliths and 50,000 monoliths (e.g., between 1000 monoliths and 30,000 monoliths or between 10,000 monoliths and 20,000 monoliths). Each monolith212can have a length in a range of about 4 inches to about 20 inches, a width in a range of about 4 inches to about 20 inches, and a height in a rage of about 4 inches to about 20 inches. In some embodiments, each monolith includes 100 cells per square inch with 100 cells per square inch. For example, in some embodiments, a monolith having a width of 10 inches and a height of 10 inches can have 10,000 cells (e.g., cells213).

For example,FIG.6illustrates reactor200having a 1×2 array (e.g., array210) of monoliths (e.g., monoliths212aand212b);FIG.7illustrates reactor200having a 12×6 array of monoliths; andFIG.8illustrates reactor200having a 10×11 array of monoliths. In some embodiments, reactor200includes one or more closures300and/or closures320. In some embodiments, reactor200includes housing302, frame304defining an opening, and F disposed around opening204.

In some embodiments, after monolith212is saturated with carbon dioxide, regenerator204can heat monolith212(e.g., using electric current602provided by power source600) to release the adsorbed carbon dioxide in monolith212. Heating monolith212is discussed in more detail below. In some embodiments, the released carbon dioxide exits reactor as carbon dioxide-rich stream106through second product stream105.

In some embodiments, fluid102flows through reactor200and contacts at least one monolith212. In some embodiments, reactor200includes at least one monolith212. In some embodiments, reactor200includes an array210of monoliths212. In some embodiments, monolith212adsorbs carbon dioxide from fluid102. In some embodiments, monolith212is a solid. In some embodiments, after monolith212adsorbs carbon dioxide, fluid104(e.g., fluid102less carbon dioxide) exits reactor200through product stream103. In some embodiments, fluid104is released to the atmosphere. In some embodiments, reactor200is disposed at an inlet to a cooling tower, and fluid104exits reactor and is used for the original purposes of fluid source100, such as a cooling media in a cooling tower.

In some embodiments, after monolith212is saturated with carbon dioxide, carbon dioxide is released from monolith212. In some embodiments, power source600applies energy to monolith212to regenerate the adsorbed carbon dioxide. In some embodiments, power source600applies electric energy to cause joule heating of sorbent214to regenerate the adsorbed carbon dioxide. In some embodiments, extracted carbon dioxide-rich stream106exists regenerator204and reactor200for collection. In some embodiments, extracted carbon dioxide-rich stream exits regenerator204and reactor200through second product stream105. In some embodiments, carbon dioxide-rich stream106comprises at least 90% carbon dioxide by volume (e.g., at least 95% carbon dioxide by volume or at least 99% carbon dioxide by volume. In some embodiments, carbon dioxide-rich stream106is sequestered for permanent removal from the atmosphere. In some embodiments, after regeneration, as discussed in detail below, monolith212can be re-used for additional adsorption and regeneration processes.

Each monolith212within reactor200can adsorb and desorb (e.g., release) carbon dioxide. The adsorption occurs when monolith212is in “contacting” mode, and desorption occurs when monolith212is in “regeneration” mode.FIG.2Aillustrates the operation of system10as monolith212adsorbs carbon dioxide in contacting mode, andFIG.2Billustrates the operation of system10when monolith212has been saturated and carbon dioxide is released in regeneration mode. In some embodiments, fluid102passes through monolith212to adsorb carbon dioxide from fluid102. In some embodiments, system10includes fan400that pulls fluid102from fluid source100through monolith212. In some embodiments, as shown inFIG.2A, fan400is provided in fluid communicate with monolith212downstream of monolith212. As illustrated inFIG.2B, adsorbed carbon dioxide can be release from monolith212by applying electric current602(e.g., from power source600) to monolith. In some embodiments, system10includes vacuum pump700downstream of monolith212to pull carbon dioxide-rich stream106from reactor200.

As illustrated inFIGS.3-5, monolith212can have various configurations of electrodes220that supply electric current602to monolith212depending on the specific equipment set up and energy needs of the system. In some embodiments, power source600applies electric current602to monolith212.FIG.4illustrates a monolith212with electrodes220contacting side surfaces of monolith212. In some embodiments, electrodes220are adhered to monolith212. In some embodiments, electrodes220are adhered to monolith212using a conductive adhesive (e.g., a carbon fiber conductive adhesive). In some embodiments, electrodes220are oriented parallel to the direction of the flow fluid102.

In some embodiments, as described in more detail below, the electric current602heats monolith212to release carbon dioxide from monolith212. In some embodiments, electric current602heats monolith212to a range of about 60° C. to about 200° C. (e.g., about 80° C. to about 180° C., about 120° C. to about 150° C.). In some embodiments, electric current602heats monolith212to a temperature of about 150° C.

In some embodiments, monolith212is heated by joule heating, which increases efficiency of the system, especially at the temperatures required for efficient release of carbon dioxide. Although the monolith can be heated by other means, these often come with various drawbacks. For example, convection heating uses a condensable gas (e.g., steam) to separate streams. Typically very high temperature steam is required to achieve acceptable rates for carbon dioxide release. This results in an expensive, energy intensive process. Moreover, convection can increase impurities in the carbon dioxide that is removed from the fluid (e.g., fluid102). Although a lower-temperature steam could be used, which could reduce energy requirements, steam at lower temperatures can take significantly longer to release carbon dioxide (e.g., on the order of hours). Conduction heating is also less efficient because the rate of release of carbon dioxide is limited by the coefficient of heat transfer of sorbent214, which in most cases is not suitable for rapid release of carbon dioxide. Radiation heating is challenging to apply to internal areas of a reactor, making it unsuitable for applications disclosed herein. Lastly, induction heating requires special doping of the monolith and large volumes of the doping materials. Accordingly, the present inventors have found that joule heating provides relatively low energy heating with rapid release of carbon dioxide.

In some embodiments, power source600provides electric current602to cause joule heating of monolith212. Joule heating applies electric current though monoliths212to cause electrons collide with atoms within monolith212, thereby releasing energy in the form of heating. Joule heating as discussed herein is more rapid and improves energy use compared to traditional heating methods. First, joule heating does not require heat transfer, so it eliminates any inefficiencies or heat losses resulted from heat transfer, thereby allowing a more rapid heating.

FIG.11illustrates the rise of temperature of a monolith (e.g. monolith212) over time using joule heating. As shown inFIG.11, joule heating according to embodiments described herein can achieve temperatures of 80° C. in about 5 seconds, temperatures of about 120° C. in about 20 seconds, and temperatures of about 150° C. in about 30 seconds. Additionally, unlike other heating methods like those discussed above, joule heating increases the temperature locally, for example, where electric current is applied. This further minimizes unnecessary energy consumption.

In some embodiments, monolith212is heated by joule heating to a temperature at which regeneration (e.g., carbon dioxide release) typically begins (e.g. approximately 80° C.) in less than 10 seconds (e.g., about 5 second to about 10 seconds). In some embodiments, monolith212is heated by joule heating to a temperature of 80° C. in about 5 seconds.

FIGS.3and4show the setup of monolith212for regeneration according to various embodiments. Electrodes220are attached to surfaces of monolith212, and power source600applies electric current to monolith212through electrodes220. In some embodiments, electrodes220are provided on the sides of monolith212parallel to the flow direction of fluid102, such that electrodes220do not obstruct the flow of fluid102. In some embodiments, electrodes220are provided on two sides of monolith212, as illustrated inFIGS.3and4. In some embodiments, electrodes220are provided on four sides of monolith, as illustrated inFIG.5. In some embodiments, electrodes220are pairs of bipolar electrodes.

In some embodiments, power source600applies electric current through a circuit. In some embodiments, the circuit can have a switch604to selectively apply electric current to specific electrodes. For example, as shown inFIG.5, when switch604is at position A, electrodes220on the left and right sides of monolith212are activated, thereby applying a current through monolith212in a horizontal direction; when switch604is at position B, electrodes220on the top and bottom sides of monolith212are activated, thereby applying a current through monolith212in a vertical direction. In some embodiments, switch604can alternate between position A and position B to cause alternating heating between horizontal and vertical directions, thereby improve the homogeneity of temperature within monolith212.FIG.13shows a set of up of an array of monoliths for regeneration according to some embodiments.

In some embodiments, power source600applies alternating current through monolith212between two electrodes220. In some embodiments, monolith212is coated with a material that forms a solid-state electrolytic cell with metal electrodes (e.g., electrodes220). Alternating current can be applied with a high frequency to reduce ionic migration within monolith212and interfacial redox reactions with electrodes220. For example, the alternating current frequency can be in a range of about 2 kHz to about 200 kHz. In some embodiments, the alternating current frequency is in a range of about 2 kHz to about 200 kHz (e.g., about 50 kHz to about 150 kHz, or about 75 kHz to about 125 kHz). In some embodiments, the alternating current frequency is about 100 kHz.

High frequency alternating current used with embodiments discussed herein can improve the lifetime of monolith212. For example, the alternation of the direction of current can outpace the harmful electrochemical processes that would have occurred within monolith212between two electrodes220, thereby increasing the efficiency and lifetime of monolith212. In some embodiments, when a high frequency alternating current is used (e.g. 2 kHz to 100 kHz), the lifetime of monolith212can be significantly increased. For example, when direct current is used, monolith212may have a lifetimes around 5 cycles. In contrast, when high frequency alternative current is used, monolith212can have a lifetime of about 1000 cycles to about 4000 cycles (e.g., about 1500 cycles). As used herein, a “cycle” includes heating monolith212to regeneration temperatures (e.g. about 75° C. to about 300° C. or about 130° C.) and cooling monolith212to ambient temperature (e.g. about −20° C. to about 32° C.).

Additionally, heating efficiency can be improved by using high frequency alternating current. For example, when a high frequency alternating current is used (e.g. 2 kHz to about 100 kHz), it can prevent the formation of an Electron Double Layer Capacitor (EDLC) forming at the interface between monolith212and electrodes220. Accordingly, the monolith-electrode cell can behave as a pure resistor, which can bring improved heating efficiency.FIGS.18A-Cillustrate the interaction at the interface of monolith212and electrodes220. As shown inFIG.18A, EDLC can form at the interface between monolith212and electrodes220when the alternating current frequency is low (e.g. about 1 Hz to about 2 kHz). When the frequency is increased to an optimized zero-phase frequency (e.g. about 2 kHz to about 110 kHz), as illustrated byFIG.18B, the phase angle between voltage and current waveforms becomes zero, and no EDLC is formed at the interface between monolith212and electrodes220. Further, as illustrated inFIG.18C, at higher frequencies with heating restrained (e.g. more than about 110 kHz), no EDLC is formed. The EDLC formed at low frequency (e.g. about 1 Hz to about 2 kHz) can cause at least two issues with functionality. First, EDLC formation can cause deposition of sorbent from monolith212, which can cause high resistance at the interface between monolith212and electrodes220. Second, EDLC formation can cause sorbent migration within monolith212that can cause non-homogenous resistance, which in turn can cause uneven temperature distribution within monolith212.

In some embodiments, electrodes22are carbon-coated electrodes. In some embodiments, carbon-coated electrodes can be used with high frequency alternating current to further optimize the lifetime of monolith212, heating distribution within monolith212, and heating efficiency. In some embodiments, a non-impregnated carbon layer is used between electrodes220and monolith212to provide a chemical barrier between the ions of sorbent214and electrodes220. In some embodiments, the non-impregnated layer of carbon is activated carbon. In some embodiments, the non-impregnated layer of carbon is not activated carbon. In some embodiments, the carbon layer can include a graphite layer having a thickness of at least about 8 μm. In some embodiments, the carbon layer has a thickness of about 8 μm to about 150 μm (e.g., about 10 μm to about 140 μm, about 20 μm to about 125 μm, about 50 μm to about 100 μm, or about 75 μm to about 100 μm). In some embodiments, the carbon layer has a thickness of about 20 μm to about 150 μm (e.g. about 50 μm to about 125 μm, about 70 μm to about 90 μm). In some embodiments, the carbon layer has a density of about 5 mg/cm2to about 10 mg/cm2, about 6 mg/cm2to about 9 mg/cm2, or about 7 mg/cm2to about 8 mg/cm2. In some embodiments, the carbon layer has a density of about 7.3 mg/cm2.

In some embodiments, the carbon layer can include a copper layer. In some embodiments, the copper layer has a thickness of at least 5 μm. In some embodiments, the copper layer has a thickness of about 5 μm to about 150 μm (e.g., about 15 μm to about 140 μm, about 20 μm to about 125 μm, about 50 μm to about 100 μm, or about 75 μm to about 100 μm. In some embodiments, the copper layer has a thickness of about 90 μm. In some embodiments, monolith212includes a sorbent214that reacts with carbon dioxide to form a carbonate. In some embodiments, the sorbent can be a metal carbonate. In some embodiments, sorbent214can be potassium carbonate, calcium carbonate, or a mixture thereof. In some embodiments, sorbent214can include an amine. In some embodiments, the amine is monoethylamine, glycine, sarcosine, polyethylenimine, (“PEI”), polyaziridine, linear and/or branched surfactants (e.g., lauric acid), or a mixture thereof.

In some embodiments, monolith212is a solid structure that is impregnated with sorbent214. Exemplary monoliths212or array210of monoliths212are illustrated inFIGS.2A-5. In some embodiments, monolith212has a structure that allows fluid102to flow through monolith. In some embodiments, monolith212is treated or impregnated (e.g., by wet impregnation) with an aqueous solution containing sorbent214.

In some embodiments, the aqueous solution for treating or impregnating monolith212can have various amounts of dissolved sorbent214. The amount of sorbent214in the solution used to impregnate monolith212can affect the cumulative amount of carbon dioxide that can be adsorbed by monolith212. For example, the solution can contain about 25 wt % to about 75 wt % (e.g., about 40 wt % to about 65 wt %) In some embodiments, the solution contains about 50 wt % of dissolved sorbent214. In some embodiments, monolith212can adsorb between about 0.4 mmol and about 0.5 mmol of carbon dioxide per gram of sorbent214. In some embodiments, monolith212is impregnated with a solution containing about 50 wt % sorbent214, and monolith212can remove between about 0.45 mmol carbon dioxide per gram of sorbent214. In some embodiments, monolith212can adsorb about 0.44 mmol CO2/g adsorbent in 400 minutes.

In some embodiments, monolith212can include conductive microporous and/or mesoporous activated carbon. In some embodiments, monolith212includes microporous activated carbon. In some embodiments, monolith212includes mesoporous activated carbon. In some embodiments, monolith212can include a hierarchical porous structure where the pores range from mesoporous to microporous.

In some embodiments, monolith212can include one or more binders. In some embodiments, monolith212includes binders, such as silicate solution, whey, baking flour, bentonite, natural clays, synthetic clays, or combinations thereof.

In some embodiments, monolith212can include one or more additives. In some embodiments, monolith212includes additives, such as graphite, formaldehyde, resorcinol, carbon fiber, carbon nanotubes, carbon nanofibers, nanodiamonds, buckyballs, pure or ligated metal (e.g., copper, aluminum, iron, gold, platinum, palladium, silver), nanoparticles or oxides thereof, zeolites, metal-organic frameworks, covalent organic frameworks, natural or synthetic silicas, polyamine polymers, polyethylene glycol, amino acids, a single or mixture of metal carbonate salts, or combinations thereof.

FIG.20illustrates a flowchart showing a method2000for manufacturing a monolith (e.g., monolith212). In some embodiments, at step2008, input materials are mixed. As illustrated inFIG.20, the input materials can include one or more of activated carbon2002, binder2004, or additives2006. Mixing at step2008can be done using various types of mixers, such as a rotary mixer, a planetary mixer, or a centrifugal mixer.

In some embodiments, at step2010, the mixture can be formed into monolith212, for example, by extrusion, molding, 3d-printing, or direct polymer synthesis with subsequent carbonization.

At step2012, in some embodiments, monolith212is dried to a moisture content of about 0 wt % to about 10 wt %. In some embodiments, monolith212is dried to a moisture content of about 2 wt %. At step2012, in some embodiments, manufactured monolith212is calcined under an inert gas at a temperature of 300° C. to about 900° C. for about 1 hour to about 24 hours. In some embodiments, monolith212is calcined at a temperature of about 700° C. In some embodiments, monolith212is calcined for about 6 hours. In some embodiments, the inert gas comprises helium, argon, nitrogen, or combinations thereof. In some embodiments, the inert gas has a purity of 99% or more.

In some embodiments, at step2014, dried and calcined monolith212is soaked in an aqueous solution of a metal (e.g., a metal carbonate or a Group 1 element salt in the periodic table). In some embodiments, the aqueous solution comprises about 5 wt % to about 50 wt % of the metal. In some embodiments, the aqueous solution comprises about 25 wt % of the metal. In some embodiments, the metal is potassium carbonate. In some embodiments, monolith212is soaked in the aqueous solution for about 1 minute to about 24 hours, such as about 10 minutes to about 15 minutes.

In some embodiments, at step2016, excess liquid is removed from soaked monolith212by passing a stream of air through each cell in monolith212and along the exterior of monolith212. In some embodiments, the stream of ambient air (e.g. about −20° C. to about 32° C.) is at a pressure between about 20 psi to about 80 psi (e.g., about 55 psi). In some embodiments, the stream of air is passed through each cell for about 1 minutes to about 60 minutes (e.g., about 10 minutes).

In some embodiments, at step2018, monolith212is dried by alternating current joule heating (described below related to method2100) and under vacuum with consistent homogenous heating at temperatures between about 25° C. to about 150° C. In some embodiments, at step2018, monolith212is dried under vacuum without heat application.

Carbon structures can be prone to cracking during drying. However, methods described related toFIG.21can reduce the tendency to crack and increases the consistency of heat distribution in carbon structures when progressive Joule heating is performed.FIG.21illustrates a flowchart showing a method2100for drying monolith212by applying alternating current joule heating.

At step2102, in some embodiments, soaked monolith212is placed in an electrical application structure. In some embodiments, the electrical application structure contains a metal plate, a foam, a carbon coated copper electrode, a carbon structure, a carbon coated copper electrode, a foam, and a metal plate. In some embodiments, the electrical application structure contains from inside to outside a metal plate, a foam, a carbon coated copper electrode, a carbon structure, a carbon coated copper electrode, a foam, and a metal plate. In some embodiments, the copper electrodes are placed on opposite sides of the carbon structure at a pressure of at least 5 lbs/in2.

At step2104, in some embodiments, monolith212is heated with alternating current. In some embodiments, the alternating current has a frequency in a range of about 1 Hz to about 100,000 Hz. In some embodiments, the alternating current has a frequency of about 60 Hz. In some embodiments, voltage is controlled, as the resistance of monolith changes with temperature, to maintain the current through monolith less than about 10 amps throughout the heating. In some embodiment, alternating current is applied until monolith212reaches 80° C.

At step2106, in some embodiments, after monolith212reaches a temperature of about 80° C., remaining steam is removed from monolith212. In some embodiments, at step2106, hot air (e.g. about 60° C. to about 100° C.) is blown over monolith212to remove any steam remaining inside monolith212. In some embodiments, the air is blown over monolith212until the temperature of monolith212is decreased to ambient temperature (e.g. about −20° C. to about 32° C.) by decreasing the temperature of the air to ambient temperature (e.g. about −20° C. to about 32° C.). In some embodiments, the temperature of monolith212can be measured by a thermocouple.

At step2108, the flow of air can be stopped. In some embodiments, at step2108, the air is blown over monolith212until no steam is observed leaving monolith212. In some embodiments, at step2108, the air is stopped after blowing for about 10 minutes to about 90 minutes.

In some embodiments, steps2106and2108are repeated until no steam is observed leaving monolith212at the beginning of the hot air flow. In some embodiments, steps2106and2108are repeated at least 5 times (e.g., at least 6 times). In some embodiments, steps2106and2108are repeated for about 60 minutes to about 120 minutes (e.g., about 75 minutes to about 90 minutes). In some embodiments, steps2106and2018are repeated for about 90 minutes. In some embodiments, voltage is increased to maintain the constant current amperage, as the resistance of monolith212increases as it dries. In some embodiments, the drying process is stopped when a pre-determined humidity level is reached. In some embodiments, humidity level in the monolith is measured by the weight of the monolith, and the drying process is stopped when about 20% to about 100% of the water weight has been removed.

At step2110, monolith212can be cooled. In some embodiments, after drying, at step2110, monolith212is cooled to room temperature under ambient conditions (e.g. about −20° C. to about 32° C.).

Method2100for drying monolith212described above can reduce the tendency for carbon structures to crack during the drying process and increases the consistency of heat distribution in carbon structures when progressive joule heating is performed.

System10can be configured to allow for continuous adsorption of carbon dioxide from fluid source100. For example, using the heating methods described herein, monoliths212can cycle between a contacting mode (e.g., shown inFIG.2A) in which carbon dioxide is adsorbed and a regeneration mode (e.g., shown inFIG.2B) in which carbon dioxide is released from the adsorber. In some embodiments, a first portion of monoliths212in array210are in contacting mode and a second portion of monoliths212in array210are in regeneration mode.

This cycling can be accomplished, for example, by providing a reactor that alternatively seals and unseals monoliths212. For example, reactor200can have one or more chambers (e.g., chambers216and218), and each chamber can have one or more monoliths212disposed within the chamber. In some embodiments, each chamber is sealed (e.g., by closure300) when monoliths disposed therein are in regeneration mode and unsealed when monoliths disposed therein are in contacting mode. In some embodiments, each chamber can be hermetically sealed. In some embodiments, each chamber can be hermetically sealed using vacuum pump (e.g., vacuum pump700). In some embodiments, closure300can move from a first position that seals a first chamber to a second position that unseals the first chamber. In some embodiments, the second position is a position that seals a second chamber. In some embodiments, closure300vacuum seals chambers of reactor200.

In some embodiments, as shown inFIG.6, closure300can be a pair of doors on opposite sides of reactor200that each slide from a first position to a second position.FIG.6illustrates a reactor having two chambers, each with one monolith disposed therein. For example, as shown inFIG.6, reactor200can include first chamber216with monolith212adisposed therein and second chamber218with monolith212bdisposed therein. In the exemplary reactor200shown inFIG.6, closure300is in the first position and first chamber216is scaled. In this position, monolith212ais in regeneration mode, meaning system10provides electric current602to monolith212ato heat monolith212aas described above, which in turn releases carbon dioxide adsorbed by monolith212a. At the same time, monolith212bis in contacting mode, meaning system10flows fluid102from fluid source100through monolith212bsuch that monolith212badsorbs carbon dioxide and fluid104(e.g., fluid102less carbon dioxide) flows out of reactor200. Once system10detects that a certain condition has been met, for example based on time elapsed, saturation level of monolith212b, or amount of carbon dioxide being released from monolith212a, closure300or320may move to a second position in which second chamber218is sealed and first chamber216is unscaled. In this portion of the cycle, the operation is reversed from what is described above, for example, monolith212ais in contacting mode and monolith212bis in regeneration mode. In some embodiments, closure300can slide within tracks206to unseal first chamber216and move to a second position in which second chamber218is scaled.

FIG.7shows another exemplary arrangement of reactor200that follows the same contacting and regeneration cycling as the reactor shown inFIG.6. For example,FIG.7shows exemplary reactor200with a first chamber216containing a first 12×6 array210of monoliths212disposed within a first chamber and a second 12×6 array of monoliths212disposed within a second chamber (shown sealed behind closure300inFIG.7). Closure300shown inFIG.7includes a pair of sliding doors that can each slide between a first position and a second position as described above related toFIG.6. In some embodiments, each door of closure300is disposed on opposite sides of the reactor. In some embodiments, when first chamber216or second chamber218is unsealed, all monoliths212disposed therein are in contacting mode. In some embodiments, when first chamber216or second chamber218is sealed, all monoliths212disposed therein are in regeneration mode.

FIG.8shows an exemplary arrangement of reactor200that includes a 10×11 array of monoliths. In some embodiments, as shown inFIG.8, closure300is a box that moves from a first position (shown inFIG.8) to a second position to seal array210. In some embodiments, closure300slides along tracks312on frame310to a second position in which a contacting end314of closure300contacts sealing surface308. In some embodiments, when closure300is in the first position (shown inFIG.8), monoliths212are in the contacting mode. In some embodiments, when closure300is in the second position, monoliths212are in the regeneration position.

FIGS.22and23show exemplary arrangement of reactor200having one or more monoliths212disposed within housing302and frame332. In some embodiments, reactor200includes one or more closures320. In some embodiments, reactor200includes two closure320. In some embodiments, a first closure320is disposed on a first side of frame332and a second closure320is disposed on a second side of frame332opposite the first side, as shown inFIG.23. In some embodiments, when both closures are open, a fluid (e.g., fluid102) can flow across monoliths212and reactor200can be in contacting mode. In some embodiments, when both closures are closed, a fluid cannot pass across monoliths212and reactor200can be in regeneration mode.

In some embodiments, closure320is hingedly coupled to reactor200. In some embodiments, closure320is coupled to frame332by at least one hinge322. In some embodiments, closure320is coupled to frame332by two hinges322.

In some embodiments, closure320can be opened and closed using one or more hydraulic cylinders324. In some embodiments, hydraulic cylinder324includes cylinder326and rod328. Hydraulic cylinder324can actuate between a retracted position and an extended position.FIG.22illustrates hydraulic cylinder324in the extended position. In some embodiments, hydraulic cylinder324moves closure320from an open position (shown inFIG.22) to a closed position. In some embodiments, in the closed position, closure320engages with clamps330on frame332. In some embodiments, clamp330can be a pneumatic or hydraulic clamp. In some embodiments, clamp330engages with closure320to secure closure320in the closed position. In some embodiments, in the closed position, closure320couples to sealing surface308to seal reactor200. In some embodiments, in the closed position, closure320is sealed under vacuum. In some embodiments, when hydraulic cylinder324extends, closure320is in the first position (shown inFIG.22), monoliths212are in the contacting mode. In some embodiments, when hydraulic cylinder324contracts, closure320is in the closed position, and monoliths212are in the regeneration mode. In some embodiments, when hydraulic cylinder324extends, closure320is in the open position, and monoliths212are in the contacting mode. In some embodiments, reactor200can include two closures320on opposite sides of reactor200. In some embodiments, reactor200is in contacting mode when both closures320are in the open position. In some embodiments, reactor200is in the regeneration mode when both closures320are in the closed position.

In some embodiments, closure320is flexible, which can allow closure320to be light and reduce material costs. In some embodiments, closure320can be used for about 25,000 cycles to about 500,000 cycles, about 35,000 cycles to about 400,000 cycles, about 45,000 cycles to about 250,000 cycles, about 75,000 cycles to about 150,000 cycles, or within a range having any two of these values as endpoints. In some embodiments, in the context of closure320, one cycle includes opening closure320and closing closure320.

In some embodiments, as shown inFIG.22, reactor200can be coupled to duct334. In some embodiments, duct334includes fan400that can be used to draw fluid (e.g., fluid102) through monoliths212. In some embodiments, multiple reactors200can be coupled to the same duct. For example, as shown inFIG.24, multiple reactors200can be stacked or placed side-by-side.FIG.23illustrates the reactor200ofFIG.22that is not coupled to duct334. an exemplary arrangement of reactor200that has a similar hinged closure320as reactor200shown inFIG.22.

Closures300and320can move between a first position and a second position. In some embodiments, closure300is slidably coupled to a reactor (e.g., reactor200) and slides between the first position and the second position. In some embodiments, closure320is hingedly coupled to a reactor (e.g., reactor200) and rotate between the first position and the second position. In some embodiments, closure320is open in the first position and closed in the second position.

In some embodiments, closure300and closure320can move between the first position and the second position based on various factors, such as time elapsed in one position, amount of fluid102entering reactor200, concentration of carbon dioxide in fluid102, carbon dioxide concentration in product stream103, or amount of carbon dioxide exiting reactor200through product stream105. In some embodiments, system10includes solenoid107in line with product stream105.

In some embodiments, closures300and320can move between the first position and the second position after closures300and/or320have been in one position for a predetermined time has elapsed. In some embodiments, the predetermined time is about 10 minutes to about 120 minutes (e.g., about 10 minutes to about 90 minutes, about 20 minutes to about 70 minutes, or about 20 minutes to about 60 minutes). In some embodiments, closures300and/or320move from a first position to a second position after a predetermined time has elapsed and then moves back to the first position after the predetermined time has elapsed again.

In some embodiments, system10includes one or more sensors for measuring concentration of carbon dioxide in fluid102and volumetric flow rate of fluid102. In some embodiments, system10includes a first sensor on inlet stream101that measures the concentration of carbon dioxide in fluid102. In some embodiments, system10includes a second sensor on inlet stream101to reactor200that measures the flow rate of fluid102entering reactor200. In some embodiments, system10includes a single sensor on inlet stream101that measures both concentration of carbon dioxide in fluid102and the flow rate of fluid102entering reactor200. In some embodiments, closures300and/or320can move between the first position and the second position based on one or more signals received from first sensor and/or second sensor. For example, in some embodiments, if system10determines, based on the one or more sensors, that a predetermined amount of carbon dioxide has entered reactor200, closures300and/or320can move between the first position and the second position. In some embodiments, the predetermined amount of carbon is about 0.15 mmol to about 1.5 mmol (e.g., about 0.25 mmol to about 1 mmol or about 0.25 mmol to about 0.5 mmol) carbon dioxide per gram of monolith disposed in each chamber.

In some embodiments, system10includes one or more sensors disposed downstream of an outlet to reactor200that measures the concentration of carbon dioxide in fluid104at product stream103. In some embodiments, a concentration of carbon dioxide in product stream103that exceeds a predetermined value can indicate that a monolith disposed within the chamber is saturated with carbon dioxide during the contacting mode. In some embodiments, if system10determines, based on the one or more sensors, that a concentration of carbon dioxide in product stream103exceeds a predetermined value, closures300and/or320can move between the first position and the second position. In some embodiments, the predetermined concentration value is about 80 wt % to 95 wt % (e.g., about 85 wt % to about 90 wt %).

In some embodiments, system10includes one or more sensors disposed downstream of an outlet to reactor200that measures the flow rate of carbon dioxide-rich stream106in product stream105. In some embodiments, a flow rate of carbon dioxide-rich stream106that is less than a predetermined value can indicate that all or substantially all of the carbon dioxide adsorbed by monolith212has been released during regeneration mode. In some embodiments, if system10determines, based on the one or more sensors, that the flow rate of carbon dioxide-rich stream106is less than a predetermined value, closure300and/or320can move between the first position and the second position. In some embodiments, the predetermined flow rate value is about 10 volume % to about 0.1 volume % (e.g., about 7.5 volume % to about 2.5 volume %). In some embodiments, one or more of the sensors described above are part of carbon dioxide analyzer502.

FIG.25illustrates an exemplary schematic of system10according to some embodiments. In some embodiments, system10includes reactor200, fan400, pressure controller500, power source600, and vacuum pump700. System10can include a control system that includes controller500, carbon dioxide analyzer502, temperature sensor504, velocity sensors506, timer508, pressure sensors510, valves512, separator514, and flow meter518.

In some embodiments, fan400draws fluid through reactor200during contacting process. In some embodiments, vacuum pump700starts to vacuum reactor200after closure300and/or320is sealed. In some embodiments, pressure sensor510measures the pressure within the sealed chamber of reactor200. In some embodiments, the output from pressure sensor510indicates whether the sealed chamber of reactor200has reached a vacuum condition and is used to determine when the regeneration process can begin. In some embodiments, pressure sensor510is a transducer coupled to reactor200.

In some embodiments, when the regeneration process begins, power source600supplies power to reactor200(or modular unit250). In some embodiments, temperature sensor504measures the temperature within the sealed chamber of reactor200, and the output from temperature sensor504is used to determine the duration of power-on and power-off of power source600. In some embodiments, temperature sensor504is an NTC thermistor. For example, in some embodiments, when temperature sensor504detects the temperature within the sealed chamber falls below a minimum temperature, power source600is turned on, and when temperature sensor504detects the temperature within the sealed chamber exceeds a maximum temperature, power source600is turned off. In some embodiments, the minimum temperature is about 80° C. and the maximum temperature is about 200° C. In some embodiments, temperature sensor504measures the temperature continuously during the regeneration process.

In some embodiments, during the regeneration process, second product stream105is fed through water separator514to separate water from carbon dioxide-rich stream106released from reactor200. In some embodiments, flow meter518measures the flowrate of carbon dioxide-rich stream106, and the output of flow meter518is used to determine when power source600can be turned off. In some embodiments, carbon dioxide analyzer502measures the carbon dioxide concentration of carbon dioxide-rich stream106, and the output of carbon dioxide analyzer502is used to determine when power source600can be turned off.

In some embodiments, solenoid valves512gate the chamber of reactor200to fan400and vacuum pump700. In some embodiments, solenoid valves512controls the sealing and venting of the chamber of reactor200. In some embodiments, solenoid valves512are controlled by controller500.

In some embodiments, monoliths212disclosed herein have a life of about 1 month to about 1 year. In some embodiments, monolith212disclosed herein can have a life of about 100 cycles to about 5000 cycles (e.g., about 500 cycles to about 3000 cycles or about 1000 cycles to about 2000 cycles). In some embodiments, one cycle is one occurrence of the contacting mode and one occurrence of the regeneration model. In some embodiments, a cycle may begin with either the contacting mode or the regeneration mode.

FIGS.9and10show exemplary reactors (reactor200) integrated with cooling towers according to some embodiments. Cooling towers (e.g., cooling tower800) draw hot air out of systems, such as refrigeration systems, HVAC systems, or industrial processes. Hot air enters cooling tower800at an inlet. In some embodiments, reactor200can be integrated into a cooling tower at the inlet of the cooling tower such that fluid102(e.g., ambient air) is drawn through reactor200before entering cooling tower800. As such, integrating reactor200with cooling tower800efficiently uses the fluid flow created by cooling tower800, which can reduce the power required by system10. Additionally, flowing fluid102through reactor200does not have a significant effect on the performance of cooling tower800.

In some embodiments, as shown inFIG.9, cooling tower800can be a one-sided inlet cooling tower. In some embodiments, as shown inFIG.10, cooling tower800can be a two-sided cooling tower (e.g., a cooling tower with more than one inlet) with two or more inlets and a reactor200at each inlet. In some embodiments, cooling tower800includes more than one inlet and reactor200is attached to every inlet of cooling tower800. In some embodiments, reactor200is a modular design with multiple chambers connected together, such that it can be used with cooling towers of different shapes and scales.

In some embodiments, extracted carbon dioxide exits reactor200as carbon-dioxide rich stream106and does not enter cooling tower800. In some embodiments, fluid104(e.g., fluid102less carbon dioxide) exits reactor200and enters cooling tower800to act as cooling media. In some embodiments, the pressure drop across reactor200is small enough that it does not impact operation of the cooling tower. In some embodiments, the pressure drop is in a range of 0.2 inches of water column to 1.1 inches of water column, 0.4 inches of water column to 0.7 inches of water column, or 0.5 inches of water column. In some embodiments, the cooling performance of fluid less carbon dioxide104is reduced less than 5% comparing to the cooling performance of fluid102, if it does not pass through reactor200.

In some embodiments, reactor200is not attached to cooling tower800but instead draws fluid102directly from the environment. In some embodiments, reactor200is a modular unit that can be assembled into a modular system20. Modular system20can include two or more modular units250. In some embodiments, modular units250can be stacked vertically, disposed horizontally, or arranged in an array (e.g., as shown inFIG.24). In some embodiments, each modular unit250includes all components of reactor200described. In some embodiments, modular unit250includes a reactor200with a closure300that slides (e.g., as illustrated inFIG.6). In some embodiments, modular unit250includes a reactor200with a closure320that is hingedly coupled to reactor250(e.g., as illustrated inFIG.22). In some embodiments, modular system20can include some modular units250with closures300and some modular units250with closures320.

Modular system20can include 2 or more modular units250. In some embodiments, modular system20can include from 2 to 600,000 modular units250. In some embodiments, the number of modular units250in modular system20is in a range from about 100 to about 550,000, from about 1000 to about 500,000, from about 5000 to about 450,000, from about 10,000 to about 400,000, from about 50,000 to about 300,000, from about 100,000 to about 200,000, or within a range having any two of these values as endpoints. In some embodiments, modular units250are arranged in an array having dimensions m×n (i.e., m columns of modular units250and n rows of modular units250), where m is an integer from 1 to 1000 and n is an integer from 1 to 1000.FIG.24illustrates a modular system20with 24 modular units250. As shown inFIG.24, m=4 and n=6. The number of modular units250can be determined based on the needs of a specific site. A benefit to the modular units250is that a modular system20can be scaled up or down as needed. In some embodiments, each modular unit250is removably coupled to the modular system20and/or to another modular unit250. For example, a first modular unit250can be removably coupled to a second modular unit250. In some embodiments, each modular unit250is removably coupled to a frame configured to accommodate numerous modular unit250. In some embodiments, modular units250can be coupled to the system (e.g., system20) using fasteners (e.g., screws and nuts). Modular units can be replaced by disconnecting components such as piping and instrumentation connections, removing fasteners, and lifting out of the cluster of modules.

In some embodiments, each modular unit250is coupled to a duct (e.g., duct334) through which air flows after passing over monolith212. In some embodiments, each modular unit250is coupled to a separate duct. In some embodiments, more than one modular unit250is coupled to the same duct. In some embodiments, all modular units250within modular system20are coupled to the same duct. In some embodiments, duct334includes a fan (e.g., fan400) that draws air from the environment, through each modular unit250, and into duct334.

Modular system20can take various forms. For example, as shown inFIGS.26and27, modular system20can include tower402with walls404of modular units250. As shown inFIG.26, each wall404can include 2 or more (e.g., 3 or more, 4 or more, 5 or more, 6 or more, 7 or more, 8 or more, 9 or more, or 10 or more) modular units250. In some embodiments, as shown inFIGS.26and27, six walls404of modular units250can be arranged to form a hexagonal shape when viewed top-down. It is to be understood that different numbers of walls404could be used to form differently shaped towers402. In some embodiments, the number of walls404is equal to the number of sides of tower402. For example, three walls404can be arranged to form a triangular shape when viewed top-down; four walls404can be arranged to form a quadrilateral (e.g., a square or a rectangle) when viewed top-down; five walls404can be arranged to form a pentagon when viewed top-down; seven walls404can be arranged to form a heptagon; or 8 walls can be arranged to form an octagon. In some embodiments, tower402includes n walls404arranged to form a shape having n sides when tower402is viewed top-down, where n is an integer from 4 to 100 . . . . Modular units250are assembled into reactor towers402.

In some embodiments, outer sides of walls404define outer sides of tower402. In some embodiments, inner sides of walls404define a duct (e.g., duct334). In some embodiments, reactor tower402includes fan400to draw fluid through each of modular units250and into duct334. In some embodiments, reactor tower402includes a single fan402. In some embodiments, reactor tower402includes multiple fans (e.g., 2 or more fans, 3 or more fans, 5 or more fans, or 10 or more fans).

In some embodiments, tower402sits on a substrate (e.g., on the ground, on a concrete pad, or on a rooftop). In some embodiments, tower402is elevated above the substrate. In some embodiments, reactor tower402includes supports412to elevate reactor tower402. In some embodiments, supports412stabilize reactor tower402. Systems disclosed herein can have any number of reactor towers402, depending on the site and conditions of the environment. In some embodiments, systems disclosed herein can include 1 or more reactor towers402(e.g., 2 or more reactor towers, 3 or more reactor towers, 5 or more reactor towers, 10 or more reactor towers). In some embodiments, system20includes two reactor towers402, as shown inFIG.26.

In some embodiments, system20includes electrical and control unit406coupled to reactor tower402. In some embodiments, site20includes carbon dioxide purification unit408connected to reactor tower.

In some embodiments, modular units250can be manufactured from sheet metal. In some embodiments, modular units250can be manufactured from sheet metal have a size of, for example, 4 ft×10 ft or 4 ft×8 ft. In some embodiments, modular units250are sized to increase shipping efficiency. In some embodiments, each modular unit250can be transported by standard shipping means (e.g., a semi-trailer, train, shipping container, etc.).

Systems (e.g., system10) disclosed herein include various electrical systems to operate, monitor, and adjust the systems. Electrical systems can include, for example, power sources that provide electricity to the systems; electrical conduits (e.g., electrodes220) for supplying electricity to monoliths for heating; and sensors for monitoring temperature of the monoliths, saturation level of monoliths, fluid composition of fluid entering system10, and amount of carbon dioxide exiting system10.

In some embodiments, one or more electrodes (e.g., electrodes220) are coupled to monolith212. In some embodiments, electrodes220are electrically coupled to a source of electricity (e.g., power source600). In some embodiments, as shown inFIG.5, four electrodes may be used on four different sides of monolith212. In some embodiments, as shown inFIG.5, system10can include switch604that switches current from one electrode220on a first side of monolith212to another electrode220that is coupled to a second side of monolith212that is perpendicular to the second side. In some embodiments, when switch604switches between electrodes220as shown inFIG.5, electric current602can pass through monolith212in an alternating fashion between horizontal and vertical. This configuration increases homogeneity of temperature within monolith212as it is headed.

FIG.13illustrates an electrical system of system10according to some embodiments. In some embodiments, system10can include 1 or more (e.g., 2 or more, 3 or more, 4 or more, or 5 or more) power sources600. In some embodiments, as shown inFIG.13, system10can include one power source per array210of monoliths212. In some embodiments, the ratio of the number of power sources600to the number of monoliths212is 1:100 to about 1:1 (e.g., about 1:50 to about 1:5 or about 1:30 to about 1:10). As discussed above, chambers containing monoliths can be hermetically sealed.FIG.13illustrates feedthrough lines606that can be used to pass electric current602and sensor signals in and out of sealed chambers. in this configuration there are multiple monoliths sharing electric leads. This allows for power of multiple. In some embodiments, as shown inFIGS.3and28, multiple series of monoliths212can be arranged in parallel, with electrodes220disposed between each series of monoliths212. In some embodiments, in the parallel arrangement, the power distribution is low voltage and high current. In some embodiments, as shown inFIGS.3and28, electrical leads can be physically connected to power multiple columns at the same time. In some embodiments, as shown inFIG.29, power is distributed to monoliths212in series. In some embodiments, in the series arrangement, the power distribution is high voltage and low current.

In some embodiments, each power source (e.g., power source600) is configured to provide a consistent direct current voltage to monoliths212or arrays210of monoliths212. In some embodiments, power source600provides a direct current (e.g., electric current602) having a voltage of about 12 volts to about 90 volts (e.g., about 30 volts to about 80 volts or about 50 volts to about 70 volts). In some embodiments, power source600provides a direct current having a voltage of about 50 volts. As discussed above, electrodes220can be adhered to monolith212. In some embodiments, the adhesive is selected such that that the connection between the monolith and the electrode is less resistive per unit length than the monolith itself. This ensures that joule heating is the main source of heat.

In some embodiments, regeneration of carbon dioxide in monoliths (e.g., monoliths212) is driven by heating monoliths with direct ohmic heating also known as joule heating. In some embodiments, monoliths212are arranged as loads in a series-parallel arrangement in order to maximize power supply efficiency and efficacy. In some embodiments, each power source (e.g., power source600) is transformed from 3-phase grid alternate current mains to direct current, and then inverted back into single phase alternate current. Through power switches, each single phase alternate current is connected to a series of monoliths212either in parallel connection (FIG.29) or series connection (FIG.28). In some embodiments, each output is connected to a series-parallel string of monoliths, and each string of monoliths is filled with monoliths of similar DC resistance. In some embodiments, the 3-phase power includes a variable DC rail, an AC inverter, and a control unit. In some embodiments, the variable DC rail operates at 20 Volts direct current (“VDC”) to 105 VDC and can produce greater than 12 kW at 105 VDC. In some embodiments, the AC inverter operates at a frequency of 100 kHz and can produce 12 kW. In some embodiments, the series-parallel string of monoliths can includes 2 or more (e.g., 4 or more, 6 or more, 8 or more, or 10 or more) rows of monoliths212, and the monoliths212can be arranged in series. Each row can be arranged parallel to the next.

One factor that affects the efficiency of the system is the resistance of the monoliths used in the system. In some embodiments, the resistance of the monoliths is designed to ensure relatively even heating throughout the array210of monoliths212. If the circuit is designed such that the monoliths are in parallel, as illustrated inFIG.14A, the voltage across each monolith will be constant, but the current and, therefore, the heating power will vary inversely with the resistance of each monolith. For example, in a two-monolith system with monoliths (represented by R1 and R2) in parallel, as shown inFIG.14A, if a constant direct current voltage is applied across the monoliths, monolith R2 will have a resistance 2 times that of R1, meaning the heating power applied to R1 will be 2 times that of R2. If the circuit is designed such that the monoliths are set in series, as shown inFIG.14B, the opposite will occur. For example, the current across both monoliths will be constant, but the voltage across R2 will be twice the voltage across R1, and therefore the heating power through R2 will be twice that across R1.

Equation 1 below shows the relationship between heat (Q), mass (m), specific heat capacity (cp), and temperature (T). Based on Equation 1 below, two monoliths with the same masses and specific heat capacities that are being heated will increase in temperature in direct relation to the amount of heating energy (e.g., electrical energy provided by electric current602) moving through each of the monoliths.
Q=m cpΔTEq. 1

As described above, the heating energy is impacted by the electrical resistance of each monolith. In some embodiments, the resistances across impregnated monoliths according to some embodiments (e.g., monoliths212) varies in the range of 5 ohms to 5,000,000 ohms. Accordingly, systems disclosed herein may be designed for resistance balancing. In some embodiments, the resistance range for monoliths being powered by a single power supply will is in a range of ±20% of the target range. In some embodiments, monoliths in parallel have a resistance range of ±100 ohms of the target range.

In some embodiments, resistivity for a monolith having dimensions of 4 inches cubed with 100 cells per square inch will be about 2.0 Ohm to about 40.0 Ohms, including the resistivity of any adhesive used to connect electrodes to the monolith. In some embodiments, the resistivity is measured perpendicular to the flow of fluid (e.g., fluid102). In some embodiments, the resistivity of monolith212is directly related to the width of monolith212as measured from one electrode surface to the other electrode surface on the opposite side. In some embodiments, the resistivity of monolith212also changes according to the water concentration or carbon dioxide amount of monolith212.

As discussed above, systems disclosed herein offer benefits of carbon dioxide capture and rapid regeneration in an energy efficient manner. In some embodiments, system10uses about 10 Joules to about 200 Joules per monolith per regeneration cycle.

In some embodiments, when system10is integrated with a cooling tower (e.g., cooling tower800), system10can remove between about 10 kg and about 10 tons of carbon dioxide per day (e.g., about 500 kg to about 3 tons of carbon dioxide per day). In some embodiments, system10can remove about 20% to about 85% (e.g., about 40% to about 70%) of carbon dioxide from fluid102.

In some embodiments, system10can be integrated into a system that includes reactor200, cooling tower800, and a sequestration system that permanently removes the carbon dioxide from the atmosphere.

FIG.15shows method1000of operating reactor200according to some embodiments. In some embodiments, at step1010fluid102flows through monolith212disposed in first chamber216. In some embodiments, at step1020, fluid102contacts monolith212such that carbon dioxide in fluid102is adsorbed by monolith212. In some embodiments, at step1030system10determines whether monolith212is saturated with carbon dioxide to a predetermined value. In some embodiments, the predetermined saturation value is in a range of 50% to 100% (e.g., 60% to 100%, 75% to 100%, or 90% to 100%). In some embodiments, the saturation value can be determined by the weight of monolith212. In some embodiments, the saturation value can be determined by monitoring the carbon dioxide concentration of fluid102that enters reactor200and the carbon dioxide concentration of fluid104that exists reactor200.

In some embodiments, if monolith212is not saturated to the predetermined value, system continues steps1010,1020, and1030until system10determines that monolith212is saturated. In some embodiments, if monolith212is saturated to the predetermined value, system10moves to step1040and seals first chamber216. In some embodiments, as discussed in detail above, the sealing first chamber216is done by sliding closure300to engage with sealing surface308. In some embodiments, at step1040, first chamber216is hermetically sealed. In some embodiments, first chamber216is sealed by vacuum pump700. In some embodiments, at step1050electric current (e.g., electric current602) is applied to monolith212to release adsorbed carbon dioxide. In some embodiments, the electric current is applies through electrode220attached to a surface of monolith212. In some embodiments, at step1060the released carbon dioxide is collected downstream of reactor200. In some embodiments, at step1060, the collected carbon dioxide is released from system10, for example through carbon dioxide-rich stream106.

In some embodiments, at step1070carbon dioxide-rich stream106is analyzed (e.g., by analyzer502) to determine the amount of carbon dioxide in carbon dioxide-rich stream106. In some embodiments, if the carbon dioxide amount in carbon dioxide-rich stream106is not less than the predetermined value, in some embodiments, method1000repeats steps1050,1060, and1070. In some embodiments, if the carbon dioxide amount in carbon dioxide-rich stream106is less than the predetermined value, this can indicate that all or substantially all of the adsorbed carbon dioxide has been released, and at step1080, system10stops applying electric current602to monolith212and unseals first chamber216. Although method1000is described with respect to first chamber216, it is to be understood that method1000can also be performed using second chamber218. In some embodiments, method1000is performed with monolith212disposed in second chamber218occurs in parallel, simultaneously, or alternating with method1000applied to monolith212disposed in first chamber216. For example, in some embodiments, when steps1010,1020, and1030are applied to monolith212disposed in first chamber216, steps1050,1060, and1070are applied to monolith212disposed in second chamber218.

FIG.16shows a method1100of operating reactor200according to some embodiments. In some embodiments, steps1110and1120are the same as steps1010and1020in method1000. In some embodiments, at step1130, the system determines if a first predetermined time has been reached. In some embodiments, if the predetermined time has been reached, method1100repeats steps1110,1120, and1130until the predetermined time has been reached. In some embodiments, if at step1130the system determines that a predetermined time has been reached, method1100proceeds to steps1140,1150,1160, which are the same as steps1040,1050,1060, respectively. In some embodiments, the first time is in a range of about 20 minutes to about 70 minutes (e.g., about 30 minutes to about 60 minutes or about 40 minutes to about 50 minutes).

In some embodiments, if the first time is not reached, method1100repeats steps1110,1120, and1130until the first time has been reached. In some embodiments, at step1170, the system determines if a second predetermined time has been reached. In some embodiments, if the second predetermined time has not been reached, the system repeats steps1150and1160. In some embodiments, if the second predetermined time has been reached, system10stops applying electric current602to monolith212and unseals first chamber216. Although method1100is described with respect to first chamber216, it is to be understood that method1100can also be performed using second chamber218. In some embodiments, method1100is performed with monolith212disposed in second chamber218occurs in parallel, simultaneously, or alternating with method1100applied to monolith212disposed in first chamber216. For example, in some embodiments, when steps1110,1120, and1130are applied to monolith212disposed in first chamber216, steps1150,1160, and1170are applied to monolith212disposed in second chamber218.

As used herein, the terms “left” and “right,” and “top” and “bottom,” and the like are intended to assist in understanding of embodiments of the disclosure with reference to the accompanying drawings with respect to the orientation of monoliths, electrodes, etc. as shown, and are not intended to be limiting to the scope of the disclosure or to limit the disclosure scope to the embodiments depicted in the Figures. The directional terms are used for convenience of description and it is understood that may be positioned in any of various orientations.

As used herein, when the term “about” is used in describing a value or an end-point of a range, the disclosure should be understood to include the specific value or end-point referred to. As used herein, the term “about” may include ±10%.

It is to be appreciated that the Detailed Description section, and not any other section, is intended to be used to interpret the claims. Other sections may set forth one or more but not all exemplary embodiments of the present disclosure as contemplated by the inventor(s), and thus, are not intended to limit the present disclosure and the appended claims in any way.

The present disclosure has been described above with the aid of functional building blocks illustrating the implementation of specified functions and relationships thereof. The boundaries of these functional building blocks have been arbitrarily defined herein for the convenience of the description. Alternate boundaries can be defined so long as the specified functions and relationships thereof are appropriately performed.

The foregoing description of the specific embodiments will so fully reveal the general nature of the disclosure that others can, by applying knowledge within the skill of the art, readily modify and/or adapt for various applications such specific embodiments, without undue experimentation, without departing from the general concept of the present disclosure. Therefore, such adaptations and modifications are intended to be within the meaning and range of equivalents of the disclosed embodiments, based on the teaching and guidance presented herein. It is to be understood that the phraseology or terminology herein is for the purpose of description and not of limitation, such that the terminology or phraseology of the present specification is to be interpreted by the skilled artisan in light of the teachings and guidance.

The above examples are illustrative, but not limiting, of the present disclosure. Other suitable modifications and adaptations of the variety of conditions and parameters normally encountered in the field, and which would be apparent to those skilled in the art, are within the spirit and scope of the disclosure.

References in the specification to “one embodiment,” “an embodiment,” “an example embodiment,” “some embodiments,” etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

The breadth and scope of the present disclosure should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the claims and their equivalents.