Systems and methods for coal-based electrothermal swing adsorption of aqueous greenhouse gases from wastewater

Abstract

In one example, the electrothermal swing adsorption system includes an electrothermal swing adsorption device having a first chamber containing at least one carbon monolith and a second chamber containing at least one carbon monolith, the electrothermal swing adsorption device receiving a supply of wastewater having at least one dissolved greenhouse gas and outputting a purified water stream and a concentrated aqueous greenhouse gas stream.

Description

[Technical Field]

[0001] cross reference This patent application is a non-provisional patent application based on U.S. Provisional Patent Application No. 63 / 481,987, filed January 27, 2023, entitled "Systems and Methods for Coal-Based Electrothermal Swing Adsorption of Aqueous Greenhouse Gases from Wastewater," the disclosure of which is incorporated herein by reference in its entirety.

[0002] FIELD OF THE INVENTION Embodiments described herein generally relate to coal-based electrothermal swing adsorption systems for capturing, concentrating, and sequestrating aqueous greenhouse gases. More particularly, the embodiments relate to systems, apparatus, and methods for capturing, concentrating, and sequestrating aqueous greenhouse gases from wastewater treatment systems of water resource recovery facilities. [Background technology]

[0003] Wastewater refers to the water resulting from the use of freshwater, raw water, potable water, or saltwater in various intentional uses or processes. Another definition of wastewater is used water resulting from any combination of domestic, industrial, commercial, or agricultural activities, surface runoff / stormwater, and sewage inflow or sewer infiltration. Water resource recovery facilities produce purified water, nutrients, renewable energy, and other useful bio-based materials from wastewater. Most wastewater contains aqueous greenhouse gases, which are treated to remove them in wastewater treatment plants or water resource recovery facilities. Aqueous greenhouse gases may include methane, nitrous oxide, carbon monoxide, and carbon dioxide. Traditionally, granular activated carbon is used to remove aqueous greenhouse gases. Summary of the Invention [Means for solving the problem]

[0004] In one example, the electrothermal swing adsorption system includes an electrothermal swing adsorption device having a first chamber containing at least one carbon monolith and a second chamber containing at least one carbon monolith, the electrothermal swing adsorption device receiving a supply of wastewater having at least one dissolved greenhouse gas, outputting a purified water stream, and outputting a concentrated aqueous greenhouse gas stream.

[0005] In one example, at least one carbon monolith in the first chamber adsorbs aqueous greenhouse gases, and at least one carbon monolith in the second chamber desorbs the greenhouse gases simultaneously with the at least one carbon monolith in the first chamber adsorbing the aqueous greenhouse gases. In one example, at least one carbon monolith in the second chamber adsorbs aqueous greenhouse gases, and at least one carbon monolith in the first chamber desorbs the greenhouse gas simultaneously with the at least one carbon monolith in the second chamber adsorbing the aqueous greenhouse gases. In one example, the first and second chambers are cyclically operated to continuously adsorb and desorb greenhouse gases, with adsorption occurring in one of the first and second chambers while desorption occurs in the other of the first and second chambers. In one example, each carbon monolith comprises coal-based activated carbon fiber. In one example, each carbon monolith is functionalized to adsorb a specific aqueous greenhouse gas. In one example, the electric thermal swing adsorption device includes a container for storing the aqueous greenhouse gas desorbed from the second carbon monolith. In one example, the electric thermal swing adsorption system includes multiple electric thermal swing adsorption devices arranged in series such that each electric thermal swing adsorption device adsorbs aqueous greenhouse gases from a supply of wastewater. In one example, each electric thermal swing adsorption device outputs an aqueous greenhouse gas stream enriched with respect to a particular aqueous greenhouse gas. In one example, each electric thermal swing adsorption device includes a container for storing the emitted particular aqueous greenhouse gas. In some examples, the electric thermal swing adsorption device further includes at least one chromatography column configured to adsorb at least one greenhouse gas dissolved in the wastewater.

[0006]

[0006] As an example, a method for removing greenhouse gases from wastewater using an electric thermal swing adsorption system includes: supplying wastewater containing aqueous greenhouse gases to a first chamber of an electric thermal swing adsorption device; adsorbing the aqueous greenhouse gases on a first carbon monolith in the first chamber; and discharging a purified water stream from the first chamber of the electric thermal swing adsorption device. As an example, the method further includes supplying purge water to a second chamber of the electric thermal swing adsorption device, separate from the first chamber, and desorbing the greenhouse gases from the second carbon monolith, which previously adsorbed the aqueous greenhouse gases, with the purge water in the second chamber. As an example, the method further includes discharging the concentrated aqueous greenhouse gas stream from the second chamber of the electric thermal swing adsorption device.

[0007] In one example, the method further includes applying an electric current to the second carbon monolith in the second chamber to increase the temperature of the second carbon monolith and desorb the greenhouse gas from the second carbon monolith. In one example, the method further includes switching the supply of wastewater containing the aqueous greenhouse gas from the first chamber to the second chamber and switching the supply of purge water from the second chamber to the first chamber when the first carbon monolith has adsorbed a predetermined amount of the aqueous greenhouse gas.

[0008] As an example, the step of adsorbing the aqueous greenhouse gas with a first carbon monolith in the first chamber can include moving the first carbon monolith in wastewater and / or purge water or gas. As an example, the method further includes adsorbing the aqueous greenhouse gas with a second carbon monolith in the second chamber and desorbing the greenhouse gas from the first carbon monolith with purge water in the first chamber. As an example, the first carbon monolith and the second carbon monolith comprise coal-based activated carbon fibers. As an example, the coal-based activated carbon fibers are functionalized to adsorb specific aqueous greenhouse gases. As an example, the electrothermal swing adsorption system can include multiple electrothermal swing adsorption devices arranged in series, where wastewater containing the aqueous greenhouse gas is supplied to each electrothermal swing adsorption device in series, and each electrothermal swing adsorption device adsorbs a specific aqueous greenhouse gas. [Brief explanation of the drawings]

[0009] The drawings illustrate several embodiments of the present disclosure, and the same reference numerals in different views or embodiments shown in the drawings refer to the same or similar elements or features.

[0010] [Figure 1] FIG. 1 shows a schematic diagram of an electric thermal swing adsorption system having multiple electric thermal swing adsorption devices according to one embodiment of the present disclosure.

[0011] [Figure 2] FIG. 1 shows a schematic diagram of an electrothermal swing adsorption device in a first configuration, according to one embodiment of the present disclosure.

[0012] [Figure 3] FIG. 1 shows a schematic diagram of an electrothermal swing adsorption device in a second configuration, according to an embodiment of the present disclosure.

[0013] [Figure 4] 1 shows a flow chart of a method for capturing, concentrating, and sequestering aqueous greenhouse gases from wastewater in a wastewater treatment system according to one embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0014] The descriptions herein are illustrative and are not intended to limit the scope, applicability, or configuration of the claims. Accordingly, changes may be made in the function and arrangement of the elements described, and various embodiments may omit, substitute, or add other steps or components, as appropriate, without departing from the spirit and scope of the present disclosure. For example, methods described may be performed in a different order than described, and various steps may be added, omitted, or combined. Additionally, features described with respect to one embodiment may be combined in other embodiments.

[0015] Aqueous greenhouse gases, such as methane, nitrous oxide, carbon monoxide, and carbon dioxide, are present in wastewater. Granular activated carbon has traditionally been used to remove aqueous greenhouse gases from wastewater. This disclosure relates to an electrothermal swing adsorption (ETA) system that utilizes a carbon monolith with activated carbon fibers to capture, concentrate, and sequester greenhouse gases. The ETA system includes two phases: capture / adsorption and release / desorption. Activation involves the capture / adsorption of aqueous greenhouse gases on the carbon monolith. Activation significantly reduces the concentrations of aqueous greenhouse gases, particularly methane, nitrous oxide, carbon monoxide, and nitrates, from the wastewater. Regeneration involves the release / desorption of the captured aqueous greenhouse gases, which is achieved by evacuating the water from the chamber before applying an electric current to the activated carbon monolith to raise its internal temperature to the range of 100°C to 150°C.

[0016] The electrothermal swing adsorption system is designed for removing aqueous greenhouse gases from the treatment streams of water resource recovery plants. It is designed and scaled for industrial and municipal wastewater treatment plants. To provide timely water filtration, the system was developed to operate in parallel within the treatment stream, continuously capturing aqueous greenhouse gases and regenerating the filter as needed in a cyclical process. Because carbon fibers conduct electricity and heat, a relatively small amount of energy is required to raise the temperature via the electrothermal swing process. While researchers have attempted to regenerate activated carbon monoliths using gas burners or external resistance elements, this electrothermal swing adsorption / desorption cycle is simpler, easier to apply and control, and consumes less energy.

[0017] FIG. 1 illustrates an electrothermal swing adsorption system 100 for capturing, concentrating, and sequestering aqueous greenhouse gases according to one embodiment of the present disclosure. The electrothermal swing adsorption system 100 includes a wastewater inlet stream 102 and a purified water outlet stream 104 that has been purified during a wastewater purification process in the electrothermal swing adsorption system 100. The term "purified" does not necessarily mean that the water is completely free of aqueous greenhouse gases, but rather that the concentration of aqueous greenhouse gases in the water has been significantly reduced. The wastewater inlet stream 102 may contain aqueous greenhouse gases. The wastewater in the wastewater inlet stream 102 may contain various greenhouse gases dissolved in the wastewater, such as methane (CH), nitrous oxide (N), carbon monoxide (CO), and carbon dioxide (CO).

[0018] Electrical thermal swing adsorption system 100 may include multiple electrical thermal swing adsorption devices 110, 120, 130 arranged in series. The illustrated embodiment shows a first electrical thermal swing adsorption device 110, a second electrical thermal swing adsorption device 120, and a third electrical thermal swing adsorption device 130. In other words, wastewater inlet stream 102 is purified by first electrical thermal swing adsorption device 110, then by second electrical thermal swing adsorption device 120, and then by third electrical thermal swing adsorption device 130. However, the disclosure is not limited in this respect, and electrical thermal swing adsorption system 100 may include more or less than three electrical thermal swing adsorption devices to purify wastewater inlet stream 102 from aqueous greenhouse gases.

[0019] In some embodiments, the electric thermal swing adsorption devices 110, 120, 130 of the electric thermal swing adsorption system 100 may be arranged in parallel. In other words, the electric thermal swing adsorption devices 110, 120, 130 may simultaneously purify the wastewater inlet stream 102 to increase the rate at which aqueous greenhouse gases are removed from the wastewater inlet stream 102.

[0020] Additionally, each of the electric thermal swing adsorption devices 110, 120, 130 of the electric thermal swing adsorption system 100 includes a concentrated aqueous greenhouse gas stream 111, 121, 131 of condensed or concentrated aqueous greenhouse gases exiting the electric thermal swing adsorption devices 110, 120, 130. Each of the electric thermal swing adsorption devices 110, 120, 130 may be functionalized to adsorb a particular greenhouse gas. For example, the first electric thermal swing adsorption device 110 may be functionalized to remove methane from the wastewater inlet stream 102, the second electric thermal swing adsorption device 120 may be functionalized to remove nitrous oxide from the wastewater inlet stream 102 after the first electric thermal swing adsorption device 110 has removed methane, and the third electric thermal swing adsorption device 130 may be functionalized to remove carbon monoxide from the wastewater inlet stream 102 after the first electric thermal swing adsorption device 110 and the second electric thermal swing adsorption device 120 have removed methane and nitrous oxide. As a result, the purified water effluent stream 104 is free of aqueous greenhouse gases. The electric thermal swing adsorption system 100 may include additional electric thermal swing adsorption devices to remove other specific aqueous greenhouse gases from the wastewater inlet stream 102. For example, the fourth electrothermal swing adsorption device may be functionalized to remove carbon dioxide from the wastewater inlet stream 102 after the first electrothermal swing adsorption device 110, the second electrothermal swing adsorption device 120, and the third electrothermal swing adsorption device 130 have removed methane, nitrous oxide, and carbon monoxide.

[0021] In some examples, the electric thermal swing adsorption devices 110, 120, and 130 include an activated carbon monolith that adsorbs aqueous greenhouse gases, as described in more detail below. In some examples, the electric thermal swing adsorption devices may include at least one chromatography column configured to adsorb at least one greenhouse gas dissolved in the wastewater. The at least one chromatography column may be arranged upstream, downstream, or in parallel with the activated carbon monolith. In some examples, two, three, or more rows of chromatography columns may be included in the electric thermal swing adsorption system 100. The chromatography columns may be arranged in series or parallel and configured to separate aqueous greenhouse gases based on differential adsorption to the sorbents of the chromatography columns as each dissolved compound or greenhouse gas passes through the column at different rates, thereby separating them into fractions.

[0022] As an example, a chromatography column can capture multiple compounds. For example, a wastewater feed can be introduced at the top of the column. Migration of each component of the wastewater feed occurs at a different rate. Components with low adsorption and affinity for the stationary phase adsorbent migrate faster than components with high adsorption and affinity for the stationary phase material. Faster-migrating components are removed first, while slower-migrating components are eluted last. For the purposes of this disclosure, "elution" is defined as the chemical process of removing ions of one material by ion exchange with another material. That is, it is a chromatographic technique in which a solvent is used to extract adsorbed substances from a solid adsorption medium. An "eluent" is the solvent or mobile phase that passes through the column. When the polarity of the eluent matches the polarity of a molecule in the sample, that molecule desorbs from the adsorbent and dissolves in the eluent.

[0023] The mobile phase or fraction of the feed stream that carries the sample components is the eluent. The mixture of solute and solvent that leaves the column is known as the "effluent." The eluent in liquid chromatography is the liquid solvent. In this example, the eluent is a wastewater feed. In some instances, the stationary phase adsorbent may pass through a wastewater feed tank and be directed to a second vessel for elution as a moving bed. In some instances, the chromatography column may be used as a stand-alone device or in combination with a manual or automated chromatography system. In some instances, the chromatography column may be combined with other electrothermal swing adsorption devices to form an electrothermal swing adsorption system 100.

[0024] The first concentrated aqueous greenhouse gas stream 111 may transfer or discharge the condensed or concentrated aqueous greenhouse gas to a first temporary storage vessel for storage. The second concentrated aqueous greenhouse gas stream 121 may transfer or discharge the condensed or concentrated aqueous greenhouse gas to a second temporary storage vessel for storage. The third concentrated aqueous greenhouse gas stream 131 may transfer or discharge the condensed or concentrated aqueous greenhouse gas to a third temporary storage vessel for storage. In some embodiments, the first, second, and third temporary storage vessels are different temporary storage vessels that store specific aqueous greenhouse gases. In some embodiments, the first, second, and third temporary storage vessels are the same temporary storage vessel that stores all of the different aqueous greenhouse gases dissolved in the wastewater.

[0025] 2 shows a schematic diagram of electric thermal swing adsorption apparatus 110 in a first configuration. While FIG. 2 shows only the schematic diagram of electric thermal swing adsorption apparatus 110 in the first configuration, electric thermal swing adsorption apparatuses 120 and 130 in the first configurations are similar to the schematic diagram of first electric thermal swing adsorption apparatus 110.

[0026] The first electrothermal swing adsorption device 110 includes a first chamber 112 and a second chamber 113. The first chamber 112 and the second chamber 113 each contain at least one carbon monolith. In some embodiments, the first chamber 112 and the second chamber 113 each contain only a single carbon monolith. In some embodiments, the first chamber 112 and the second chamber 113 may each contain multiple carbon monoliths.

[0027] In the illustrated embodiment, the first chamber 112 contains an activated carbon monolith that adsorbs aqueous greenhouse gases, and the second chamber 113 contains a regenerated carbon monolith that desorbs the captured greenhouse gases. The regenerated carbon monolith in the second chamber 113 has previously adsorbed aqueous greenhouse gases. In some embodiments, the carbon monolith in the second chamber 113 may not yet have adsorbed aqueous greenhouse gases when initially placed in the second chamber 113. The first chamber 112 and the second chamber 113 are cyclically operated to continuously adsorb and desorb aqueous greenhouse gases.

[0028] The carbon monoliths in the first chamber 112 and the second chamber 113 each contain coal-based activated carbon fibers. The coal-based activated carbon fibers are derived from coal feedstock, making them 50% to 75% more economical than existing commercially available fibers made from polyacrylonitrile (PAN), rayon, and petroleum pitch precursors. The carbon fibers are produced by melt-blowing isotropic pitch derived from subbituminous coal ore via a direct coal liquefaction process. These novel carbon fiber monoliths eliminate the need for binders and one carbonization step.

[0029] Carbon monoliths and coal-based activated carbon fibers may be functionalized to adsorb specific greenhouse gases. Functionalization of activated carbon fibers with specific compounds is possible, as oxygen-containing functional groups have been evaluated and demonstrated with activated carbon fibers doped with silica nanoparticles. For example, these modifications include the capture of direct and indirect aqueous greenhouse gases (e.g., methane, nitrous oxide, carbon monoxide, and carbon dioxide), dyes, organics, and metals. The properties of activated carbon fibers may be tailored to achieve selective adsorption. These properties may include pore size, pore size distribution, Brunauer-Emmett-Teller (BET) specific surface area, thermal conductivity, bulk density, air permeability, and electrical resistivity. In some cases, functionalization may include protein binding or release in response to a change in charge. Such selective release may provide carbon-neutral methane. The carbon monolith in the first chamber 112 and the carbon monolith in the second chamber 113 may be similar so that each carbon monolith targets the same specific greenhouse gases for adsorption.

[0030] For example, the bulk density of a carbon monolith is approximately 0.05 g / cm 3 In some instances, the bulk density of the carbon monolith is about 0.05 g / cm 3 to approximately 0.7 g / cm 3 In some examples, the fiber area weight range may be in the range of about 0.7 g / cm 3 In another example, the bulk density may be less than 0.6 g / cm 3 Less than 0.5g / cm 3 Less than or equal to 0.1g / cm 3 In some examples, the bulk density of the carbon monolith may be less than about 0.05 g / cm 3 to approximately 0.2 g / cm 3 Other ranges may include about 0.2 g / cm 3 to approximately 0.4 g / cm 3 , approximately 0.4 g / cm 3 to about 0.5 g / cm 3 , about 0.5g / cm3 to approximately 0.6 g / cm 3 , or about 0.6 g / cm 3 to approximately 0.7 g / cm 3 In some instances, the bulk density can be adjusted by adjusting the rate of temperature increase during the formation of the carbon fiber monolith, and can also be adjusted by adjusting the air flow or oxygen concentration during the formation of the carbon fiber monolith.

[0031] In some cases, the air permeability of a carbon monolith may vary primarily based on bulk density. In some cases, the air permeability may also be affected by the fiber spacing and the degree of fusion at the nodes when forming the carbon fiber monolith. In some cases, the air permeability of a carbon monolith may be greater than about 1×10 -10 m 2 to approximately 8.5 x 10 -10 m 2 In some instances, the air permeability range may be in the range of about 9.8×10 -10 m 2 In other examples, the air permeability may be less than about 9.5×10 -10 m 2 Less than 9.0 x 10 -10 m 2 Less than, or about 8.8 x 10 -10 m 2 In some instances, the air permeability of the carbon monolith may be less than about 1×10 -10 m 2 to approximately 9.8 x 10 -10 m 2 Other ranges may be in the range of about 9.8×10 -10 m 2 to approximately 9.5 x 10 -10 m 2 , about 9.5×10 -10 m 2 to approximately 9.3 x 10 -10 m 2 , about 9.3×10 -10 m 2 to approximately 9.0 × 10 -10 m 2 , about 9.0×10 -10 m 2 to approximately 8.8 x 10-10 m 2 , or approximately 8.8 × 10 -10 m 2 to approximately 8.5 x 10 -10 m 2 The intrinsic permeability of a porous medium, such as a carbon monolith, measures its ability to pass a fluid under the influence of a pressure gradient. In practical applications, it is very important to predict the permeability of a given medium based on its pore structure.

[0032] Additionally, the properties of the activated carbon fibers may be tailored to reduce the temperature and energy required to desorb greenhouse gases from the carbon monolith. As described in more detail below, an electric current can be applied to the carbon monolith to cause the electrical resistance of the carbon fibers within the carbon monolith to generate heat, increasing its temperature and facilitating the desorption process for removing greenhouse gases from the regenerated carbon monolith.

[0033] First electrothermal swing adsorption unit 110 includes a wastewater feed 114. The wastewater feed 114 may be the same as the wastewater inlet stream 102. The wastewater feed 114 includes aqueous greenhouse gases dissolved in the wastewater. The wastewater in wastewater feed 114 may include a variety of different aqueous greenhouse gases, such as methane, nitrous oxide, carbon monoxide, and carbon dioxide, dissolved in the wastewater.

[0034] A wastewater supply 114 flows along a wastewater supply flow path 115, which includes a first wastewater supply flow path 115A. The wastewater supply flow path 115 is introduced or received into a first chamber 112 via the first wastewater supply flow path 115A. Aqueous greenhouse gases are adsorbed by the activated carbon monolith within the first chamber 112, thereby purifying the wastewater supply 114. The first chamber 112 is connected to a purified water discharge stream 104, and the purified wastewater supply 114 is discharged from the first chamber 112 via the first purified water discharge stream 104A. The purified water discharge streams 104, 104A are free of aqueous greenhouse gases due to their adsorption by the activated carbon monolith within the first chamber 112. In some embodiments, the carbon monolith in first chamber 112 is functionalized for a particular greenhouse gas, and the purified water discharge stream 104, 104A does not contain that particular greenhouse gas, but may contain additional aqueous greenhouse gases that are removed by a subsequent electrothermal swing adsorption device (e.g., 120, 130) placed in series after the wastewater inlet stream 102 of the electrothermal swing adsorption system 100. As described above, the purified water discharge stream 104, 104A may be introduced into the second electrothermal swing adsorption device 120 and then into the third electrothermal swing adsorption device 130. When the wastewater feed 114 is discharged from all of the electrothermal swing adsorption devices 110, 120, 130 as the purified water discharge stream 104, the electrothermal swing adsorption system 100 can achieve significant reductions in aqueous greenhouse gases and nitrates.

[0035] The first electrothermal swing adsorption device 110 further includes a purge 116. The purge 116 is a reservoir of purge water used to desorb greenhouse gases from the carbon monolith in the second chamber 113. In some embodiments, a purge gas may be used in the desorption process. The purge 116 flows along a purge flow path 117, including a first purge flow path 117A. The purge 116 is introduced or received into the second chamber 113 via the first purge flow path 117A. The greenhouse gases are desorbed from the regenerated carbon monolith in the second chamber 113. The regeneration of the regenerated carbon monolith in the second chamber 113 is accomplished by applying an electric current to the regenerated carbon monolith, causing the carbon monolith's electrical resistance to generate heat and raise its temperature, which may range from 100°C to 150°C, depending on the characteristics of the carbon monolith in the second chamber 113, the captured greenhouse gases desorbed from the carbon monolith, and any chemical modifications of the carbon monolith. In some embodiments, the purge water may be evacuated from the chamber prior to applying an electric current to the carbon monolith. The greenhouse gases are desorbed from the carbon monolith and enter purge 116. The condensed or concentrated aqueous greenhouse gases may be evacuated from second chamber 113 via first concentrated aqueous greenhouse gas stream 111A through concentrated aqueous greenhouse gas stream 111.

[0036] The concentrated aqueous greenhouse gas stream 111 may be connected from the first electrothermal swing adsorption device 110 to a temporary storage vessel 118 that collects and stores condensed or concentrated greenhouse gases, particularly from the first chamber 112. As described above, the temporary storage vessel 118 may collect and store the particular greenhouse gases adsorbed by the carbon monolith in the first electrothermal swing adsorption device 110. In some embodiments, the temporary storage vessel 118 may include a flow path 119 in fluid communication with the wastewater supply flow path 115 via a first flow path 119A and in fluid communication with the purge flow path 117 via a second flow path 119B.

[0037] The first electrothermal swing adsorption device 110 operates continuously and cyclically. In other words, a wastewater feed 114 (e.g., wastewater inlet stream 102) is continuously introduced into the first chamber 112 to adsorb aqueous greenhouse gases from the wastewater feed 114, and a purge 116 is continuously introduced into the second chamber 113 to desorb greenhouse gases from the carbon monolith in the second chamber 113. When the activated carbon monolith in the first chamber 112 begins to reach a predetermined adsorption capacity (in other words, when the carbon monolith cannot adsorb any more greenhouse gases), the first electrothermal swing adsorption device 110 may be switched off. In other words, the carbon monolith in the first chamber 112 is regenerated by desorbing greenhouse gases using the purge 116, and the carbon monolith in the second chamber 113 is activated by adsorbing aqueous greenhouse gases from the wastewater feed 114. Thus, first electrothermal swing adsorption device 110 uses carbon monoliths in first chamber 112 and second chamber 113 to continuously adsorb and desorb greenhouse gases.

[0038] 3 shows a schematic diagram of first electrothermal swing adsorption apparatus 110 in a second configuration. The second configuration of first electrothermal swing adsorption apparatus 110 is the reverse of the first configuration. While FIG. 3 shows a schematic diagram of first electrothermal swing adsorption apparatus 110 in the second configuration, electric thermal swing adsorption apparatuses 120 and 130 in the second configuration are similar to the schematic diagram of first electrothermal swing adsorption apparatus 110 in the second configuration.

[0039] The first electrothermal swing adsorption device 110 in the second configuration includes a first chamber 112 and a second chamber 113. In the illustrated second configuration of the first electrothermal swing adsorption device 110, the first chamber 112 includes a regenerated carbon monolith that desorbs greenhouse gases, and the second chamber 113 includes an activated carbon monolith that adsorbs aqueous greenhouse gases. Previously, the regenerated carbon monolith in the first chamber 112 was the activated carbon monolith in the first configuration, and the activated carbon monolith in the second chamber 113 was the regenerated carbon monolith in the second chamber 113 in the first configuration. In this manner, the first chamber 112 and the second chamber 113 are cyclically operated to continuously adsorb and desorb greenhouse gases.

[0040] First electrothermal swing adsorption unit 110 includes a wastewater feed 114. Wastewater feed 114 may be the same as wastewater inlet stream 102. Wastewater feed 114 includes aqueous greenhouse gases dissolved in the wastewater.

[0041] The wastewater supply 114 flows along a wastewater supply flow path 115, which includes a second wastewater supply flow path 115B. The wastewater supply flow path 115 is introduced or received into the second chamber 113 via the second wastewater supply flow path 115B. Aqueous greenhouse gases are adsorbed by the activated carbon monolith in the second chamber 113, thereby purifying the wastewater supply 114. The activated carbon monolith in the second chamber 113 is the regenerated carbon monolith of the second chamber 113 in the first configuration. The second chamber 113 is connected to a purified water discharge stream 104, and the purified wastewater supply 114 is discharged from the second chamber 113. The purified water discharge stream 104 is greenhouse gas-free because the greenhouse gases have been desorbed by the activated carbon monolith in the second chamber 113. In some embodiments, the carbon monolith in the first chamber 112 is functionalized so that the purified water discharge stream 104, 104A does not contain that particular greenhouse gas, but may contain additional greenhouse gases that are removed by a subsequent electrothermal swing adsorption device (e.g., 120, 130). As described above, the purified water discharge stream 104 may be introduced into the second electrothermal swing adsorption device 120 and then into the third electrothermal swing adsorption device 130. By treating the wastewater feed 114 as described above, significant reductions in aqueous greenhouse gases and nitrates can be achieved.

[0042] The first electrothermal swing adsorption device 110 further includes a purge 116. The purge 116 is a reservoir of purge water used to desorb greenhouse gases from the carbon monolith in the first chamber 112 in the second configuration. In some embodiments, a purge gas may be used in the desorption process. The purge 116 flows along a purge flow path 117, which includes a second purge flow path 117B that is different from the first purge flow path 117A. The purge 116 is introduced or received into the first chamber 112 via the second purge flow path 117B. The aqueous greenhouse gases are desorbed from the regenerated carbon monolith in the first chamber 112, which was the activated carbon monolith in the first configuration. Regeneration of the regenerated carbon monolith in first chamber 112 is accomplished by applying an electric current to the regenerated carbon monolith, causing the carbon monolith's electrical resistance to generate heat and raise its temperature, which can range from 100°C to 150°C depending on the characteristics of the carbon monolith in first chamber 112, the greenhouse gases being desorbed from the carbon monolith, and any chemical modifications of the carbon monolith. In some embodiments, purge water may be evacuated from the chamber prior to applying an electric current to the carbon monolith. Aqueous greenhouse gases are desorbed from the carbon monolith and enter purge 116. Condensed or concentrated aqueous greenhouse gases in purge 116 may be transported out of first chamber 112 through concentrated aqueous greenhouse gas stream 111 via second concentrated aqueous greenhouse gas stream 111B.

[0043] 4 shows a flow chart of a method 200 for capturing, concentrating, and sequestering aqueous greenhouse gases from wastewater at a wastewater treatment facility using a first electrothermal swing adsorption device 110. However, the method is also applicable to a second electrothermal swing adsorption device 120 and a third electrothermal swing adsorption device 130.

[0044] Step 202 involves providing a wastewater feed 114 containing aqueous greenhouse gases to a first chamber 112 of a first electrothermal swing adsorption device 110. The wastewater feed 114 may include one or more aqueous greenhouse gases, such as methane, nitrous oxide, carbon monoxide, and carbon dioxide. Step 204 involves adsorbing the aqueous greenhouse gases on a first carbon monolith in the first chamber 112. In some embodiments, the first carbon monolith may be functionalized to adsorb specific aqueous greenhouse gases. In some embodiments, the carbon monolith may be functionalized to adsorb one or more aqueous greenhouse gases.

[0045] In some examples, adsorbing the aqueous greenhouse gas with the first carbon monolith in the first chamber 204 may include moving the first carbon monolith through the wastewater. In other words, step 204 may include establishing a moving bed that moves the carbon monolith through the wastewater and then moves the carbon monolith to another location to release the captured aqueous greenhouse gas components.

[0046] Step 206 involves discharging the purified water discharge stream 104 from the first chamber 112 of the first electrothermal swing adsorption device 110. In some embodiments, the purified water discharge stream 104 does not contain the particular aqueous greenhouse gases adsorbed by the first carbon monolith in the first chamber 112, but may contain additional aqueous greenhouse gases that are removed by the electrothermal swing adsorption devices 120, 130.

[0047] Step 208 involves providing purge water to a second chamber 113 of the first electrothermal swing adsorption device 110, separate from the first chamber 112. Step 210 involves desorbing greenhouse gases from the second carbon monolith with the purge water in the second chamber 113. The adsorption of aqueous greenhouse gases in the first chamber 112 occurs simultaneously with the desorption of greenhouse gases in the second chamber 113. In some embodiments, the second carbon monolith may have previously adsorbed aqueous greenhouse gases. In some situations, the second carbon monolith may not have adsorbed any aqueous greenhouse gases, such as when the carbon monolith is first added to the second chamber 113 and used for the first time. Step 212 involves applying an electric current to the second carbon monolith in the second chamber 113 to increase the temperature of the regenerated carbon monolith and desorb the captured greenhouse gases from the regenerated carbon monolith. The temperature can be increased to a range of 100°C to 150°C. This temperature increase is performed to accelerate the desorption process. Therefore, the temperature increase is performed simultaneously with the desorption step 210. Step 214 involves discharging the concentrated aqueous greenhouse gas stream 111 from the second chamber 113 of the first electrothermal swing adsorption device 110.

[0048] Step 216 involves switching the supply of wastewater containing the aqueous greenhouse gas from the first chamber 112 to the second chamber 113 and switching the supply of purge water from the second chamber 113 to the first chamber 112 when the first carbon monolith has adsorbed a predetermined amount of the aqueous greenhouse gas. In other words, this occurs when the carbon monolith reaches a predetermined adsorption capacity. In some embodiments, the first chamber 112 and the second chamber 113 may each include a sensor to monitor the amount of aqueous greenhouse gas adsorbed by the carbon monolith, and based on that, switch the first electrothermal swing adsorption device 110 to remove the aqueous greenhouse gas from the carbon monolith so that it can be reused. In some embodiments, the carbon monolith may adsorb the aqueous greenhouse gas for a predetermined time based on the concentration of the aqueous greenhouse gas in the wastewater. This predetermined time may be determined by carbon monolith adsorption calculations. Thus, the second carbon monolith in the second chamber 113 can adsorb aqueous greenhouse gases, and the carbon monolith in the first chamber 112 can desorb the greenhouse gases captured within the carbon monolith.

[0049] Carbon fiber is a good conductor of electricity and heat, and the amount of energy required to raise its temperature via the electrothermal process is relatively small. The low cost of coal-based activated carbon fiber and the low operating costs of electrothermal swing adsorption / desorption enable coal-based electrothermal swing adsorption to be cost-competitive with existing conventional municipal water treatment systems, especially when using granular activated carbon. Compared to conventional systems, i.e., granular activated carbon, electrothermal swing adsorption offers at least 60% lower carbon intensity with reduced energy consumption and a longer cycle life compared to granular activated carbon.

[0050] There are at least three benefits to implementing electrothermal swing adsorption of aqueous greenhouse gases. First, there is a direct and indirect reduction in energy consumption. Second, there is a significant reduction in methane, nitrous oxide, and carbon monoxide emissions in wastewater treatment. Third, there is a reduction in the use and reliance on granular activated carbon in wastewater treatment.

[0051] As used herein, the terms "about" or "substantially" refer to a tolerance of ±10% or ±5% from the value of the term modified by "about" or "substantially." Furthermore, the terms "less than," "less than or equal to," "greater than," "more than," or "more than or equal to" include the value modified by "less than," "less than or equal to," "greater than," "more than," or "more than or equal to" as endpoints.

[0052] While various aspects and embodiments have been disclosed herein, other aspects and embodiments are also contemplated. For purposes of explanation, the description herein uses specific nomenclature to provide a thorough understanding of the disclosed embodiments. However, it will be apparent to those skilled in the art that specific details are not required to practice the disclosed embodiments. Thus, the descriptions of the specific embodiments set forth herein have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the embodiments to the precise forms disclosed. It will be apparent to those skilled in the art that numerous modifications and variations are possible in light of the above disclosure.

[0053] Various inventions have been described herein with reference to specific embodiments and examples. However, those skilled in the art will recognize that many variations are possible without departing from the scope and spirit of the invention disclosed herein. Thus, the invention as set forth in the appended claims is intended to encompass all variations and modifications thereof that do not depart from the spirit of the invention disclosed herein. As used in the specification and claims, the terms "including" and "having" are intended to be synonymous with the term "comprising."

Claims

1. 1. An electric thermal swing adsorption system including an electric thermal swing adsorption device, The electrothermal swing adsorption device is a first chamber containing at least one carbon monolith; a second chamber containing at least one carbon monolith; Equipped with the electrothermal swing adsorption device is configured to receive a supply of wastewater having at least one greenhouse gas dissolved therein; the electrothermal swing adsorption device discharges a purified water stream; the electrothermal swing adsorption device outputs a concentrated aqueous greenhouse gas stream. Electrically heated swing adsorption system.

2. 10. The electrothermal swing adsorption system of claim 1, wherein the at least one carbon monolith in the first chamber adsorbs aqueous greenhouse gases and the at least one carbon monolith in the second chamber desorbs greenhouse gases simultaneously as the at least one carbon monolith in the first chamber adsorbs aqueous greenhouse gases.

3. 10. The electrothermal swing adsorption system of claim 1, wherein the at least one carbon monolith in the second chamber adsorbs aqueous greenhouse gases and the at least one carbon monolith in the first chamber desorbs greenhouse gases simultaneously as the at least one carbon monolith in the second chamber adsorbs aqueous greenhouse gases.

4. 2. The electrothermal swing adsorption system of claim 1, wherein the first chamber and the second chamber are cyclically operated to successively adsorb and desorb greenhouse gases, with adsorption occurring in one of the first chamber and the second chamber while desorption occurs in the other of the first chamber and the second chamber.

5. 10. The electric thermal swing adsorption system of claim 1, wherein each carbon monolith comprises coal-based activated carbon fiber.

6. 10. The electrothermal swing adsorption system of claim 1, wherein each carbon monolith is functionalized to adsorb a specific aqueous greenhouse gas.

7. 3. The electric thermal swing adsorption system of claim 2, wherein the electric thermal swing adsorption device comprises a container for storing aqueous greenhouse gases desorbed from the at least one carbon monolith in the second chamber.

8. 10. The electric thermal swing adsorption system of claim 1, comprising a plurality of electric thermal swing adsorption devices arranged in series such that each electric thermal swing adsorption device adsorbs aqueous greenhouse gases from the supply of wastewater.

9. 10. The electric thermal swing adsorption system of claim 8, wherein each electric thermal swing adsorption device outputs an aqueous greenhouse gas stream enriched for a particular aqueous greenhouse gas.

10. 10. The electric thermal swing adsorption system of claim 9, wherein each electric thermal swing adsorption device includes a container for storing the particular aqueous greenhouse gas emitted.

11. 10. The electric thermal swing adsorption system of claim 1, wherein the electric thermal swing adsorption device further comprises at least one chromatography column configured to adsorb the at least one greenhouse gas dissolved in the wastewater.

12. 1. A method for removing greenhouse gases from wastewater utilizing an electrothermal swing adsorption system, comprising: supplying wastewater containing aqueous greenhouse gases to a first chamber of an electrothermal swing adsorption device; adsorbing the aqueous greenhouse gases on a first carbon monolith in the first chamber; Discharging the purified water stream from the first chamber of the electrothermal swing adsorption device; A method comprising:

13. providing purge water to a second chamber of the electrothermal swing adsorption device separate from the first chamber; desorbing greenhouse gases from a second carbon monolith that previously adsorbed aqueous greenhouse gases with the purge water in the second chamber; 13. The method of claim 12, comprising:

14. 14. The method of claim 13, further comprising the step of discharging a concentrated aqueous greenhouse gas stream from the second chamber of the electrothermal swing adsorption device.

15. 14. The method of claim 13, further comprising applying an electric current to the second carbon monolith in the second chamber to increase the temperature of the second carbon monolith and desorb the greenhouse gas from the second carbon monolith.

16. 14. The method of claim 13, further comprising the step of switching a supply of wastewater containing the aqueous greenhouse gas from the first chamber to the second chamber and switching a supply of purge water from the second chamber to the first chamber when the first carbon monolith has adsorbed a predetermined amount of the aqueous greenhouse gas.

17. 13. The method of claim 12, wherein adsorbing the aqueous greenhouse gas with a first carbon monolith in the first chamber comprises moving the first carbon monolith through the wastewater, purge water, or gas.

18. 14. The method of claim 13, wherein the first carbon monolith and the second carbon monolith comprise coal-based activated carbon fiber.

19. 20. The method of claim 18, wherein the coal-based activated carbon fiber is functionalized to adsorb specific aqueous greenhouse gases.

20. 14. The method of claim 13, wherein the electric thermal swing adsorption system comprises a plurality of electric thermal swing adsorption devices arranged in series, the wastewater containing the aqueous greenhouse gas being supplied to each electric thermal swing adsorption device in series, and each electric thermal swing adsorption device adsorbing a particular aqueous greenhouse gas.

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