Direct removal of carbon dioxide from seawater using composite membranes

Abstract

In a common embodiment, composite contact membranes are presented for the direct removal of carbon dioxide from seawater. In some cases, the composite membrane comprises a support layer having a first surface and a second surface opposite to it, and a carbon dioxide selective layer disposed on the first surface. The carbon dioxide selective layer is configured to come into contact with an aqueous solution containing dissolved carbon dioxide and to selectively transport the dissolved carbon dioxide from the aqueous solution through the support layer to the second surface.

Description

Technical Field

[0001] [Cross - Reference to Related Applications] This application claims priority to U.S. Provisional Patent Application No. 63 / 491,507, titled "Direct Removal of Carbon Dioxide from Seawater Based on Composite Membranes," filed on March 21, 2023. The entire content of the priority document is incorporated herein by reference.

[0002] [Technical Field] The following description relates to the direct removal of carbon dioxide from seawater based on composite membranes.

Background Art

[0003] Direct ocean capture (DOC) technology is a promising option for the very large - scale and diverse carbon removal industries needed to mitigate conventional carbon dioxide emissions that are exacerbating anthropogenic climate change. Robust, energy - efficient, and low - cost strategies for the direct removal of carbon dioxide from seawater and other natural waters are focused on addressing the challenges and opportunities unique to operation in the marine environment.

Summary of the Invention

[0004] [Government Support] This invention was made with government support under Contract No. DE - AR001636 awarded by the Advanced Research Projects Agency of the U.S. Department of Energy. The U.S. government has certain rights in this invention.

Brief Description of the Drawings

[0005] [Figure 1] FIG. 1 is a schematic diagram showing an embodiment of an exemplary direct ocean capture (DOC) system. <着

[0006] [Figure 2A] FIGS. 2A and 2B are schematic diagrams showing embodiments of an exemplary composite membrane. [Figure 2B]Figures 2A and 2B are schematic diagrams showing exemplary composite film configurations.

[0007] [Figure 3A] Figure 3A is a schematic diagram showing an exemplary contactor module.

[0008] [Figure 3B] Figure 3B is an electron microscope image showing a cross-sectional view of an embodiment of a contactor module, as shown in Figure 3A, with hollow fibers supported before and after coating with a carbon dioxide selective layer.

[0009] [Figure 4] Figure 4 is a flowchart illustrating an exemplary process for direct marine capture using an exemplary composite membrane.

[0010] [Figure 5A] Figure 5A is a schematic diagram showing the experimental setup for the DOC system.

[0011] [Figure 5B] Figure 5B is a graph showing the carbon dioxide removal efficiency as a percentage, as a function of the feedwater flow rate (milliliters / minute (mL / min)), for various types of composite membrane-based contactor modules.

[0012] [Figure 6] Figure 6 is a flowchart showing an exemplary process for manufacturing a composite film.

[0013] [Figure 7] Figure 7 is a flowchart illustrating an exemplary process for manufacturing a composite film.

[0014] [Figure 8] Figure 8 is a flowchart illustrating an exemplary process for manufacturing a composite film. [Modes for carrying out the invention]

[0015] In some embodiments described herein, composite membranes are used for liquid degassing applications, particularly for carbon dioxide removal in direct ocean capture (DOC) systems. In certain examples, a composite membrane may comprise one or more carbon dioxide selective layers supported on a support structure (e.g., a planar composite membrane, a hollow fiber composite membrane structure, or another type of support structure). In some cases, a single contactor module may house multiple composite membranes. In some cases, multiple composite membranes within a single contactor module may be configured such that, during operation, the carbon dioxide selective tanks of the composite membrane may come into contact with a liquid supply flow (e.g., seawater) flowing across the surface of a first side of the composite membrane, and a sweep gas or vacuum may be applied to the second side opposite the composite membrane. The contactor module, during operation, allows the transport of carbon dioxide across one or more carbon dioxide selective layers and support structures from the first side to the second side opposite the composite membrane, while preventing or minimizing the liquid or water flow. In other words, the carbon dioxide selective layer can selectively transport dissolved carbon dioxide, and dissolved carbon dioxide in an aqueous solution can selectively permeate the carbon dioxide selective layer. In some implementations, the DOC system may include one or more contactor modules.

[0016] In some implementations, the systems and technologies described herein may offer technical advantages and improvements. For example, these systems and technologies may maximize the material transport area per unit volume, enabling efficient carbon dioxide removal from DOC systems, reduce the cost of equalizing carbon dioxide from DOC systems, and improve the energy efficiency of DOC systems. In some cases, these systems and technologies may also reduce competition for useful land, allow access to offshore carbon dioxide storage sites, generate valuable offshore carbon dioxide streams for fuels and chemical synthesis, or directly reverse ocean acidification caused by anthropogenic carbon dioxide emissions. In some cases, combinations of these and other potential advantages and improvements may be obtained.

[0017] FIG. 1 is a block diagram of an exemplary direct ocean capture (DOC) system 100. The exemplary DOC system 100 shown in FIG. 1 includes one or more contactor modules 102 and a control system 106. Each of the one or more contactor modules 102 includes one or more composite membranes 104. The one or more composite membranes 104 within the contactor module 102 are configured to be separated into at least one first chamber for the contactor module 102 to flow seawater through and at least one second chamber for collecting carbon dioxide gas. The DOC system 100 may include additional or different features, and the components of the DOC system may operate as described with respect to FIG. 1 or in another manner.

[0018] In some implementations, the first chamber of the contactor module 102 is configured to receive and contact seawater containing dissolved carbon dioxide gas. In some cases, seawater having a pH value of 8.1 may be acidified before being received by the contactor module 102. In other words, the pH value of the seawater received at the input port of the contactor module 102 can be lowered, and the acidified seawater contacts the surface of the composite membrane 104 facing the first chamber. For example, the pH value of the acidified seawater can be 6, 5, 4, or other values, and in certain cases where it is above a certain value, the seawater can be screened (filtered), filtered, heated, or otherwise processed before the acidification treatment.

[0019] In some embodiments, the acidification process includes the step of mixing an acidic solution with the treated seawater. In some cases, the acidic solution includes hydrochloric acid (HCl), or other types of acids. In some cases, the acidic solution used to obtain the acidified seawater can be generated on-site as part of an exemplary DOC system 100 using electrodialysis treatment, or can be obtained in another manner. In some embodiments, the acidic solution introduced into the seawater during the acidification process can react with the bicarbonate and dissolved inorganic carbon in the form of bicarbonate in the seawater, convert the dissolved inorganic carbon into carbon dioxide gas, and increase the concentration of dissolved carbon dioxide gas in the acidified seawater. In some cases, other treatments or other procedures can be used on the seawater to increase the concentration of the dissolved carbon dioxide gas.

[0020] In some embodiments, the composite membrane 104 is configured to selectively remove the dissolved carbon dioxide gas from the acidified seawater. For example, when the acidified seawater flows through the first chamber from the first end connected to the liquid inlet 112 of the contactor module 102 to the opposite second end connected to the liquid outlet 114 of the contactor module 102, and a vacuum or a gas sweep is applied to the second chamber, the concentration of the dissolved carbon dioxide gas in the acidified seawater in the first chamber decreases in the direction of the liquid flow. The composite membrane 104 contacts the acidified seawater, selectively permeates the dissolved carbon dioxide gas in the acidified seawater, and transports it through the composite membrane 104. In other words, the dissolved carbon dioxide gas is separated from the acidified seawater in the first chamber by the composite membrane 104 and into the second chamber. The dissolved carbon dioxide gas can be removed from the first chamber and collected in the second chamber. In some embodiments, the permeated carbon dioxide gas is collected at the gas outlet 116 of the contactor module 102.

[0021] In some implementations, the control system 106 is communicatively coupled to one or more control units (e.g., a water pump, a flow sensor, a vacuum pump, a pressure sensor, etc.) to adjust the pH and flow rate of seawater passing through the first chamber, as well as the flow rate or vacuum (e.g., partial pressure) of the sweep gas applied to the second chamber. In some cases, the control system 106 may be coupled to other components of the DOC system 100 to control other parameters. For example, the control system 106 may be coupled to a gas chromatograph configured to analyze and evaluate the carbon dioxide concentration collected from the second chamber, a pH sensor configured to measure the pH value of seawater, a water pump configured to supply an acidic solution to seawater during the acidification process, and other components or devices of the DOC system 100. In some implementations, the control system 106 includes a computing device, a memory unit, an input / output interface, or other components that allow the control system 106 to communicate with other components of the DOC system 100, determine the control parameter values ​​of those components of the DOC system 100, and optimize the carbon dioxide removal performance of the DOC system 100. In some cases, the control system 106 may be configured to perform other functions.

[0022] In some cases, multiple contactor modules 102 within the DOC system 100 may be connected in series. For example, seawater may pass through a series of contactor modules 102 until certain conditions are met (e.g., until the concentration of dissolved carbon dioxide gas in the seawater falls below a predetermined threshold). In some cases, acidified seawater may be processed in parallel by operating multiple contactor modules simultaneously, thereby improving productivity. In some cases, each subset of contactor modules 102 may be connected in series, and multiple subsets of contactor modules 102 may be connected in parallel. Multiple contactor modules 102 may include multiple composite membranes 104 characterized by multiple different types of composite membranes, e.g., different materials or different geometric dimensions for the carbon dioxide selective layer, different geometric dimensions for the support layer (e.g., thickness, inner diameter, porosity, pore size distribution, etc.), or different numbers of composite membranes. In some cases, multiple contactor modules 102 may operate under different conditions (e.g., different pH values, pressure, flow rate, flow direction, etc.). In some cases, the output of the DOC system 100 contains acidified seawater in which the concentration of dissolved carbon dioxide gas has decreased. The acidified seawater from the liquid outlet 114 of the contactor module 102 can be neutralized by injecting an alkaline solution (e.g., sodium hydroxide NaOH) to raise the pH value during alkalization treatment before being returned to the ocean. In some cases, the carbon dioxide gas collected from multiple composite membranes 104 can be collected for subsequent treatment.

[0023] Figures 2A and 2B are schematic diagrams showing exemplary embodiments of the composite membrane 200. The exemplary composite membrane 200 includes a support layer 202 and a carbon dioxide selective layer 204 disposed on a first surface of the support layer 202. In some implementations, the composite membrane 200 has a planar two-layer composite membrane structure. The thickness of the support layer 202 is 10 micrometers or more, 50 micrometers or more, 100 micrometers or more, 200 micrometers or more, or other values ​​or more. The thickness of the carbon dioxide selective layer is 50 micrometers or less, 20 micrometers or less, 10 micrometers or less, or other values ​​or less. In some implementations, the carbon dioxide selective layer 204 and the support layer 202 have stable chemical and mechanical stability under the operating conditions of the composite membrane 200 (e.g., under vacuum, under a specific pressure difference, in contact with a flow of acidified seawater, etc.). The carbon dioxide selective layer 204 has selectivity for dissolved carbon dioxide in seawater compared to other dissolved gases in seawater (e.g., oxygen, nitrogen, etc.). In some implementations, the selectivity for CO2 permeation to N2 or O2 in the carbon dioxide selective layer (e.g., CO2 permeability / N2 or O2 permeability) is greater than 1. For example, the selectivity for CO2 permeation to N2 in the carbon dioxide selective layer (e.g., CO2 permeability / N2 permeability) is in the range of 3.4 to 9.5, and the selectivity for CO2 permeation to O2 in the carbon dioxide selective layer (e.g., CO2 permeability / O2 permeability) is in the range of 2.4 to 4.8. In some cases, the composite membrane 200 can be implemented similarly to the composite membrane 104 in Figure 1, or in other embodiments. In some implementations, the composite membrane 200 includes a polymer or polymer mixture configured to reduce the solubility of water / water vapor in the carbon dioxide selective layer 204, thereby reducing water transport while maintaining efficient CO2 transport. In some implementation configurations, the composite film 200 is configured within a contactor module (for example, contactor module 102 in Figure 1), which is divided into a first chamber 212 and a second chamber 214, and the composite film 200 enables high CO2 removal efficiency from the aqueous solution in the first chamber 212 to the second chamber 214.

[0024] During operation, the composite membrane 200 may be configured within a contactor module (e.g., contactor module 102 in the DOC system 100 in Figure 1) such that a liquid (e.g., acidified seawater as shown in Figure 1) is in contact with the carbon dioxide selective layer 204 and a vacuum is applied to the second surface opposite the support layer 202. In this case, carbon dioxide moves across the carbon dioxide selective layer 204, then across the support layer 202, from the first surface of the support layer 202 to the second surface opposite it. In some cases, the composite membrane 200 may be configured within a contactor module in a different manner. For example, the composite membrane 200 may be configured such that the second surface of the support layer 202 is in direct contact with seawater to collect carbon dioxide from the carbon dioxide selective layer 204. In some cases, the support layer 202 of the composite membrane 200 may be configured in a different manner, for example, sandwiched between two or more carbon dioxide selective layers 204. In some cases, the exemplary composite film 200 may be mounted in the same manner as the composite film 104 in Figure 1, or in a different manner, and may be operated to perform the operations of the exemplary process 400 in Figure 4, or in a different manner, and may be manufactured using the operations of the exemplary processes 700, 800 as shown in Figures 7 and 8, or in a different manner.

[0025] In some implementations, the support layer 202 includes a single layer of polysulfone (PSf), a single layer of polyethersulfone (PES), a single layer of polyvinylidene fluoride (PVDF), a single layer of ceramic material, or a single layer of other material. In some cases, the support layer 202 includes a single layer of a mixture of two or more materials including polysulfone (PSf), polyethersulfone (PES), polyvinylidene fluoride (PVDF), ceramic material, or other material. In some cases, the support layer includes two or more layers of materials including polysulfone (PSf), polyethersulfone (PES), polyvinylidene fluoride (PVDF), ceramic material, or other material.

[0026] In some implementations, the carbon dioxide selective layer 204 includes a single layer of a silicone polymer, a single layer of a polyolefin polymer, a single layer of a fluoropolymer, a single layer of a polyacetylene-derived polymer, or a single layer of another type of carbon dioxide selective material. In some implementations, the carbon dioxide selective layer 204 includes a single layer of a mixture of two or more of the silicone polymer, polyolefin polymer, fluoropolymer, polyacetylene-derived polymer, or another type of carbon dioxide selective material. In some implementations, the carbon dioxide selective layer 204 includes two or more layers of a material containing a silicone polymer, a polyolefin polymer, a fluoropolymer, or another type of carbon dioxide selective material. The silicone polymer includes polydimethylsiloxane (PDMS) or another silicone polymer. The polyolefin polymer includes polymethylpentene (PMP) or another polyolefin polymer. The fluoropolymer includes polytetrafluoroethylene (PTFE) or another type of fluoropolymer. Polyacetylene derivative polymers include poly(1-trimethylsilyl-1-propyne) (PTMSP) or other types of polyacetylene derivative polymers.

[0027] In some cases, the support layer 202 has a porous structure, and stacking the carbon dioxide selective layer 204 on top of the porous structure of the support layer 202 can result in different overall interface structures of the composite membrane 200. As shown in Figure 2B, the carbon dioxide selective layer 204 in the composite membrane 210 may have an abrupt interface with the support layer 202. In this case, the surface pores 212 of the porous support layer 202 may not be filled with the carbon dioxide selective layer 204, for example, there may be no intrusion layer. As shown in Figure 2B, the surface pores 212 of the porous support layer 202 in the composite membrane 220 may be partially filled with the carbon dioxide selective layer 204, for example, an intrusion layer 222 may be formed in at least a portion of the surface pores of the support layer 202. In some cases, the intrusion layer 232 may extend through the surface pores 212. In other words, as shown in the composite membrane 230, the surface pores 212 of the porous support layer 202 may be completely filled with the carbon dioxide selective layer 204. In some cases, the interface structure of the composite film 200 may be a combination of the interface structures shown in Figure 2B.

[0028] Figure 3A is a schematic diagram showing an exemplary contactor module 300. The exemplary contactor module 300 includes a plurality of composite films 302 having a hollow fiber composite film structure. In some cases, the exemplary contactor module 300 may be implemented in the same manner as the contactor module 102 in Figure 1, or in a different manner, and may be operated to perform the operation of the exemplary process 400 in Figure 4, or in a different manner.

[0029] As shown in Figure 3A, each composite membrane 302 within the contactor module 300 includes a support layer 312 and a carbon dioxide selective layer 314. The carbon dioxide selective layer 314 is configured to efficiently degas a liquid (for example, to remove carbon dioxide gas dissolved in acidified seawater). The thickness of the carbon dioxide selective layer 314 is 200 micrometers or less, 100 micrometers or less, 50 micrometers or less, 10 micrometers or less, or any other value or less. The support layer 312 has a porous hollow fiber composite membrane structure and is configured to provide a high surface area for carbon dioxide gas extraction from the shell side 324 to the lumen side 322. The support layer 312 of the composite membrane 302 may be implemented in the same manner as the support layer 202 of the exemplary composite membrane 200 in Figures 2A and 2B, or in other embodiments. The carbon dioxide selective layer 314 of the composite membrane 302 may be implemented in the same manner as the exemplary carbon dioxide selective layer 204 of the composite membrane 200 in Figures 2A and 2B, or in other embodiments. In some implementations, the composite membrane 302 having a hollow fiber composite membrane structure may be manufactured according to the operation of exemplary processes 600, 700, and 800, or in other embodiments (e.g., conventional coating methods such as dip coating and spray coating, or methods of forming a thin film layer on the outer surface of fibers by curing or drying coated fibers after chemical vapor deposition). The composite membrane 302 is configured to selectively remove gases containing carbon dioxide from liquid feedwater (e.g., acidified seawater) while minimizing or preventing liquid penetration. In some cases, the composite membrane 302 has a carbon dioxide removal efficiency of 50% or more, 60% or more, 70% or more, 80% or more, or other values ​​or more.

[0030] Figure 3B is an electron microscope image showing an exemplary cross-sectional view of a supporting hollow fiber before (330) and after (332) coating with the carbon dioxide selective layer 336. The carbon dioxide selective layer 336 is coated on the outer surface of the supporting hollow fiber 334 and contains polydimethylsiloxane (PDMS). The supporting hollow fiber 334 is a porous hollow fiber made of polyvinylidene fluoride (PVDF). The thickness of the PDMS carbon dioxide selective layer 336 is in the range of approximately 20 to 35 micrometers. The composite membrane 332 having the hollow fiber composite membrane structure shown in Figure 3B has an effective composite membrane area of ​​approximately 100 cm². 2 (Table 1) can be used to prepare the contactor modules shown. Table 1. Characteristics of membrane contactor (MC) modules manufactured using PDMS-PVDF thin-film composite (TFC) hollow fiber composite films. TIFF2026509586000002.tif45155

[0031] In some implementations, fiber packing density can be defined as the cross-sectional area occupied by the fibers divided by the total cross-sectional area of ​​the membrane module. This is calculated as: number of fibers × π × (fiber outer diameter / 2) 2 π × (inner diameter of contactor module housing) 2 It may be equal to / 4 (if a cylindrical module is used) or the value obtained by dividing by the module's inner width × module's inner length (if rectangular). The composite membrane active area = total surface area of ​​fibers based on fiber outer diameter = number of fibers × π × fiber outer diameter × effective fiber length.

[0032] Figure 4 is a flowchart illustrating an exemplary process 400 for direct ocean capture. The exemplary process 400 may be used, for example, to operate a DOC system, e.g., the exemplary DOC system 100 in Figure 1. For example, the exemplary process 400 may be used to perform direct carbon dioxide removal from seawater using a contactor module having multiple composite membranes. The composite membranes of the DOC system may be implemented similarly to the composite membranes 104, 200, 210, 220, 230, 302, and 332 shown in Figures 1, 2A, 2B, 3A, and 3B, or in other embodiments. The exemplary process 400 may include additional or different operations, including operations performed by additional or different components. These operations may be performed in the order shown, or in a different order. In some implementations, one or more operations of the exemplary process 400 may be performed by a computer system, for example, by a digital computer system having one or more digital processors (for example, data processing devices in the control system 106 in Figure 1) that execute commands (for example, commands stored in a memory unit in the control system 106 in Figure 1).

[0033] In step 402, seawater containing dissolved carbon dioxide is obtained. For example, surface seawater may be collected from the ocean. In some cases, the obtained seawater may be pretreated to remove impurities, debris, or contaminants. In some embodiments, the dissolved carbon dioxide in the obtained seawater is in the form of inorganic carbon, such as carbonates and bicarbonates.

[0034] In step 404, the obtained seawater is acidified. The collected seawater is acidified to increase the concentration of dissolved carbon dioxide and to promote carbon dioxide removal. This can be carried out using various acids, such as sulfuric acid (H2SO4) or hydrochloric acid (HCl). These acids react with carbonates and bicarbonates in the seawater, converting them into carbon dioxide gas and increasing the concentration of dissolved carbon dioxide gas in the obtained seawater.

[0035] In step 406, acidified seawater is brought into contact with the first surface of the composite membrane. The acidified seawater may pass through a contactor module housing multiple composite membranes. In some cases, a carrier gas (e.g., nitrogen, air, etc.) and / or vacuum may be applied to the second side opposite the composite membrane. The acidified seawater is brought into contact with the first side of the composite membrane. The composite membrane is configured to selectively move carbon dioxide gas from the first side to the second side opposite the composite membrane. The carrier gas or vacuum applied to the second side may provide a partial pressure less than or equal to Henry's constant × (concentration of CO2 in the liquid) for efficient carbon dioxide removal.

[0036] In step 408, carbon dioxide is collected on the second side of the composite membrane. The carbon dioxide may pass through the composite membrane and flow into the carrier gas and / or vacuum environment. The carrier gas is passed through another channel of the contactor module (for example, toward the second chamber 214 of the composite membrane 200 in Figure 2A, or toward the lumen side 322 of the composite membrane 302 in Figure 3A) and processed to remove carbon dioxide from the remainder of the carrier gas. The collected carbon dioxide may be stored for further processing.

[0037] Figure 5A is a schematic diagram showing the experimental setup of the DOC system 500. The DOC system 500 comprises a contactor module 502 including a plurality of composite membranes 302 as shown in Figure 3A. A feed solution containing 2.2 mmol (mM) of dissolved carbon dioxide gas and having a pH of 4 or higher can be supplied to the composite membrane by pumping a sodium bicarbonate solution and a hydrochloric acid solution simultaneously to the contactor module 502 using a peristaltic pump 504. The feed side pressure and feed water pH can be monitored using an analog pressure gauge and a pH meter, respectively. The feed water is delivered to the shell side of the hollow fiber composite membrane (e.g., shell side 324 as shown in Figure 3A) at the liquid inlet 512 of the contactor module 502 and collected from the liquid outlet 514 of the contactor module 502, while a vacuum pump 506 may be used to draw gas from the lumen side of the hollow fiber composite membrane at the gas outlets 516A and 516B of the contactor module 502. The vacuum pump 506 may be implemented as a diaphragm vacuum pump or other vacuum pump. The composition of the gas collected from the composite membrane may be analyzed using a gas chromatograph 508 (e.g., a multi-gas analyzer #5 from SRI Instruments in Torrance, California). The gas pressure and gas flow rate on the fiber lumen side may be measured using a digital pressure gauge 510 and a mass flow meter 512, respectively.

[0038] A model feed solution containing a 2.2 mM NaHCO3 solution and a 2.6 mM HCl solution can be supplied to the composite membrane shell side at a feed rate of approximately 5–30 mL / min, while simultaneously applying a vacuum of 20 millibars or less to the fiber lumen side. The composition of the gas collected on the fiber lumen side can be analyzed using a GC with helium as the carrier gas. The system allows stabilization of each run before recording the measurements. In a transverse flow membrane contactor module manufactured using PDMS-TFC-PVDF fibers (Table 1) (e.g., feed water flows perpendicular to the fibers), the CO2 removal efficiency (defined as the ratio of the molar flow rate of CO3 gas extracted from the fiber lumen side to the molar flow rate of dissolved CO3 in the feed water supplied to the composite membrane) can be maximized to approximately 75% when the feed rate is 10 mL / min (curve 522 in plot 520 in Figure 5B). For parallel flow membrane contactor modules manufactured using the same PDMS-TFC-PVDF fibers (e.g., feedwater flows in the same direction as the fibers), the CO3 removal efficiency is approximately 25% at the same feed flow rate of 10 mL / min (curve 524 in plot 520 of Figure 5B).

[0039] Figure 6 is a flowchart illustrating an exemplary manufacturing process 600. The manufacturing process 600 is used to produce an exemplary composite membrane 302 having the composite hollow fiber composite membrane structure shown in Figure 3A.

[0040] In step 602, a first doping solution is prepared. For example, the first doping solution contains a material for the carbon dioxide selective layer dissolved in a solvent. The concentration of the material for the carbon dioxide selective layer in the solvent can be controlled according to the desired properties of the carbon dioxide selective layer. For example, if the carbon dioxide selective layer contains PDMS, the PDMS can be dissolved in a solvent such as toluene or hexane to form the first doping solution. The first doping solution can be filled into a first syringe. The first syringe can be attached to a first syringe pump used to control the supply rate of the first doping solution. In some cases, the first doping solution may contain a mixture of materials dissolved in a solvent, or multiple first doping solutions can be prepared for multiple carbon dioxide selective layers. In some cases, the first doping solution may contain other materials, including other polymers, other inorganic materials, etc. In some cases, the first doping solution can be prepared in a different manner. For example, the mixing process may be heated above room temperature. In another example, a vacuum may be applied to degas the solution, removing air bubbles that could cause defects in the cast film.

[0041] In step 604, a second doping solution is prepared. For example, the second doping solution includes a support layer material dissolved in a solvent. The concentration of the support layer material in the solvent can be controlled according to the desired properties of the support layer (e.g., thickness, porosity, etc.). For example, if the support layer contains PVDF, the PVDF can be dissolved in a solvent such as N,N-dimethylacetamide (DMAc), dimethylformamide (DMF), or N-methylpyrrolidone (NMP) to form the second doping solution. The second doping solution can be filled into a second syringe. The second syringe can be attached to a second syringe pump used to control the supply rate of the second doping solution. In some cases, the second doping solution may contain a mixture of materials dissolved in a solvent, or multiple second doping solutions may be prepared for multiple support layers. In some cases, the second doping solution may contain other materials, including other polymers, other inorganic materials, etc. In some cases, the second doping solution may be prepared in a different manner. For example, the mixing process may be heated above room temperature. In another example, a vacuum may be applied to degas the solution to remove air bubbles that may cause defects in the cast film.

[0042] In step 606, one or more fibers are extruded using the first and second doping solutions. For example, the first and second doping solutions are extruded through a spinneret having a circular orifice with two concentric tubes connected to first and second syringes filled with the first and second doping solutions. The spinneret is configured to produce a double-layered hollow fiber by extruding the two concentric tubes of the first and second doping solutions. In some cases, the spinneret may be modified to include multiple concentric tubes to allow the extrusion of hollow fibers having multiple carbon dioxide selective layers with one or more support layers. In some cases, various first doping solutions for various carbon dioxide selective layers may be prepared. In some cases, parameters of the extrusion process, such as pressure, speed, and temperature, may be controlled depending on the desired properties of the composite hollow fiber.

[0043] In step 608, the extruded fibers are solidified. For example, the extruded composite hollow fibers are immersed in one or more solidification baths with non-solvent and / or temperature changes, during which the extruded fibers solidify to form composite hollow fibers. The solidified fibers may be washed with a non-solvent and dried for further processing. In some cases, the extruded fibers may be solidified by another means of evaporating the solvent, such as passing the fibers through a heated airflow.

[0044] Figure 7 is a flowchart illustrating an exemplary manufacturing process 700. The manufacturing process 700 is used to produce exemplary composite films 200, 302 having the composite film structure shown in Figures 2A and 3A.

[0045] In step 702, a doping solution for the carbon dioxide selective layer is prepared. In some implementations, operation (step) 702 may be implemented similarly to operation (step) 602 of the exemplary process 600 in Figure 6, or it may be implemented in a different manner.

[0046] In step 704, a coating of the doping solution is formed on the porous hollow fiber. For example, by allowing the hollow fiber to come into contact with the coating solution, a coating of the doping solution can be formed on the inner or outer surface of the hollow fiber. The outer surface of the fiber can be coated simply by immersing the supporting fiber in the doping solution for a certain period of time. This can also be achieved by spray coating the fiber with the doping solution using a spray coating device. The inside of the fiber can be coated by injecting the doping solution only into the lumen side, allowing the inner surface of the fiber to come into contact with the doping solution, and then removing the doping solution from the lumen of the fiber.

[0047] In step 706, a carbon dioxide selective layer is formed on the porous hollow fibers. In some implementations, the carbon dioxide selective layer is formed on the porous hollow fibers, which may be cured and dried to solidify the coating layer. The coated porous hollow fibers may be washed to remove any residual coating material and dried for further processing.

[0048] Figure 8 is a flowchart illustrating an exemplary manufacturing process 800. The manufacturing process 800 is used to manufacture an exemplary composite film 200 having a planar composite film structure as shown in Figure 2A. In some implementations, the operations (steps) in exemplary process 800 may be implemented similarly to the operations (steps) in exemplary process 600, in which case the slot die has a double-slot structure and is configured to manufacture a double-layer composite film structure. In some cases, the slot die has multiple slots that allow for the simultaneous co-extrusion of multiple layers. In some cases, the first and second doping solutions may be extruded separately and laminated together. In some cases, doctor blades or other techniques may be used. For example, multiple doctor blades may be used to cast multiple thin films in a continuous manner. The first layer is cast with a doctor blade, the second layer is cast on top of the first layer using another doctor blade, and so on.

[0049] Some of the subjects and operations (processes) described herein may be implemented in digital electronic circuits, or in computer software, firmware, or hardware, including structures disclosed herein and their structural equivalents or one or more combinations thereof. Some of the subjects described herein may be implemented as one or more computer programs, i.e., one or more modules of computer program instructions, encoded on a computer storage medium for execution by a data processing device or for controlling its operation. The computer storage medium may be, or may be, a computer-readable storage device, a computer-readable storage board, a random or serial access memory array or device, or one or more combinations thereof. Furthermore, although the computer storage medium is not a propagated signal, the computer storage medium may be a source or destination of computer program instructions encoded into an artificially generated propagated signal. The computer storage medium may be, or may be, one or more separate physical components or media.

[0050] Some of the operations (processes) described herein may be implemented as operations (processes) performed by a data processing device on data stored in one or more computer-readable storage devices, or on data received from other sources.

[0051] The term "data processing device" encompasses all types of devices, equipment, and machines for processing data, including, for example, programmable processors, computers, systems on a chip, or a combination of these. Such devices may include dedicated logic circuits such as FPGAs (field-programmable gate arrays) and ASICs (application-specific integrated circuits). In addition to hardware, such devices may also include code that generates the execution environment for the computer program, such as code that constitutes processor firmware, protocol stacks, database management systems, operating systems, cross-platform runtime environments, virtual machines, or a combination of one or more of these.

[0052] Computer programs (also known as programs, software, software applications, scripts, or code) can be written in any form of programming language, including compiled languages, interpreted languages, declarative languages, and procedural languages, and can be deployed in any form, either as standalone programs or as modules, components, subroutines, objects, or other units suitable for use in a computing environment. Computer programs may, but do not necessarily, correspond to files in a file system. A program may be part of a file that holds other programs or data (e.g., one or more scripts stored in a markup language document), a single file dedicated to the program, or multiple coordinated files (e.g., a file containing one or more modules, subprograms, or parts of code). Computer programs can be deployed to run on a single computer or on multiple computers located in one site or distributed across multiple sites interconnected by a communication network.

[0053] Some of the processes and logic flows described herein may be performed by having one or more programmable processors execute one or more computer programs to perform operations on input data and generate outputs. Processes and logic flows may also be performed by dedicated logic circuits such as FPGAs (Field-Programmable Gate Arrays) or ASICs (Application-Specific Integrated Circuits), and the device may be implemented in this manner.

[0054] In a typical embodiment, composite membranes are proposed for the direct removal of carbon dioxide from seawater.

[0055] In the first embodiment, the composite film comprises a support layer having a first surface and a second surface on the opposite side, and a carbon dioxide selective layer disposed on the first surface, wherein the carbon dioxide selective layer is configured to come into contact with an aqueous solution containing dissolved carbon dioxide and to selectively permeate the dissolved carbon dioxide.

[0056] The implementation of the first embodiment may include one or more of the following features: The support layer includes polysulfone (PSf), polyethersulfone (PES), polyvinylidene fluoride (PVDF), or a ceramic material. The support layer includes at least two of polysulfone (PSf), polyethersulfone (PES), polyvinylidene fluoride (PVDF), and a ceramic material.

[0057] The implementation of the first embodiment may include one or more of the following features: The carbon dioxide selective layer includes a silicone polymer. The silicone polymer includes polydimethylsiloxane (PDMS). The carbon dioxide selective layer includes a polyolefin polymer. The polyolefin polymer includes polymethylpentene (PMP). The carbon dioxide selective layer includes a fluoropolymer. The carbon dioxide selective layer includes a polyacetylene-derived polymer. The polyacetylene-derived polymer includes poly(1-trimethylsilyl-1-propyne) (PTMSP). The fluoropolymer includes polytetrafluoroethylene (PTFE). The carbon dioxide selective layer includes at least one of the silicone polymer, polyolefin polymer, polyacetylene-derived polymer, or fluoropolymer.

[0058] The implementation of the first embodiment may include one or more of the following features: The carbon dioxide selective layer has a thickness of 50 micrometers or less, a thickness of 20 micrometers or less, or a thickness of 10 micrometers or less. The carbon dioxide selective layer has selectivity for the dissolved carbon dioxide gas in the aqueous solution with respect to other dissolved gases in the aqueous solution.

[0059] The implementation of the first embodiment may include one or more of the following features: The support layer has a hollow cylindrical structure. The first surface is the inner surface of the hollow cylindrical structure, and the second surface is the outer surface of the hollow cylindrical structure. The inner diameter of the hollow cylindrical structure is 2 millimeters or less. The outer diameter of the hollow cylindrical structure is 3 millimeters or less. The support layer has a porous structure. The carbon dioxide selective layer partially fills the porous structure and terminates at a predetermined depth between the first surface and the second surface of the support layer. The aqueous solution contains seawater. The concentration of carbon dioxide in the aqueous solution is parts per million (ppm) or more. The aqueous solution has a pH value of 4 or more.

[0060] In the second embodiment, a method for separating dissolved carbon dioxide gas from an aqueous solution comprises the steps of: obtaining the aqueous solution; contacting the aqueous solution with the first surface of the composite membrane of the first embodiment; and collecting the dissolved carbon dioxide gas from the second surface of the composite membrane.

[0061] The implementation of the second embodiment may include one or more of the following features: The method further comprises a step of acidifying the aqueous solution before the step of contacting the aqueous solution.

[0062] In the third embodiment, the system for separating dissolved carbon dioxide gas from an aqueous solution comprises one or more composite membranes as in the first embodiment.

[0063] The implementation of the third embodiment may include one or more of the following features: The system further comprises means for providing a driving force between the first surface and the second surface of the composite film so that the dissolved carbon dioxide gas selectively penetrates the carbon dioxide selective layer from the first surface to the second surface of the composite film. The means for providing a driving force between the first surface and the second surface of the composite film includes a pressure difference between the first surface and the second surface of the composite film. The pressure difference is 10 4 It is greater than Pascal.

[0064] The implementation of the third embodiment may include one or more of the following features: The system further comprises a liquid inlet configured to introduce the aqueous solution to the first surface of the composite membrane; a liquid outlet configured to receive liquid residue; a pump configured to pass the aqueous solution from the liquid inlet to the liquid outlet; and a gas outlet configured to collect the permeated carbon dioxide gas. The system comprises a plurality of contactor modules, each contactor module having a plurality of composite membranes, and the plurality of contactor modules are connected in series with each other. The system comprises a plurality of contactor modules, each contactor module having a plurality of composite membranes, and the plurality of contactor modules are connected in parallel with each other. The system further comprises means for monitoring the performance of the composite membranes. The system further comprises means for acidifying the aqueous solution. The dissolved carbon dioxide is in the form of dissolved inorganic carbon (DIC).

[0065] In the fourth embodiment, the direct marine capture system comprises the composite membrane of the first embodiment.

[0066] The implementation of the fourth embodiment may include one or more of the following features: A direct ocean capture system comprises a contactor module having a composite membrane configured to separate a reactor into a first chamber and a second chamber, and a control system, wherein the control system is configured to perform operations including adjusting the pH value of the aqueous solution, supplying the aqueous solution to the first chamber of the contactor module so that the aqueous solution flows through the first chamber at a certain flow rate and pressure from one end to the opposite second end, adjusting the partial pressure in the second chamber of the contactor module, and evaluating the flow rate of carbon dioxide gas from the second chamber of the contactor module.

[0067] This specification contains many details, which should not be understood as limitations on the scope of patent claims, but rather as descriptions of features specific to particular examples. Specific features described herein, or specific features shown in the drawings in the context of separate implementations, can be combined. Conversely, various features described or illustrated in the context of a single implementation can be implemented individually in multiple implementations, or in any appropriate subcombination.

[0068] Similarly, while the diagrams show operations (processes) in a specific order, it should not be understood that such operations (processes) must be performed in a specific order or sequence shown in the diagram, or that all illustrated operations (processes) must be performed, in order to obtain the desired result. Under certain circumstances, multitasking and parallel processing may be advantageous. Furthermore, the separation of various system components in the aforementioned implementation forms should not be understood as necessary in all implementation forms, and the described program components and systems can generally be integrated into a single product or packaged into multiple products.

[0069] Several embodiments have been described. However, it will be understood that various modifications are possible. Accordingly, other embodiments are also within the scope of the following claims.

Claims

1. It is a composite film, A support layer having a first surface and a second surface on the opposite side, A carbon dioxide selective layer disposed on the first surface, Equipped with, The carbon dioxide selective layer is configured to come into contact with an aqueous solution containing dissolved carbon dioxide, and to selectively transport the dissolved carbon dioxide from the aqueous solution to the second surface via the support layer. A composite film characterized by the following features.

2. The support layer contains polysulfone (PSf) The composite film according to feature 1.

3. The support layer contains polyethersulfone (PES) The composite film according to feature 1.

4. The support layer contains polyvinylidene fluoride (PVDF). The composite film according to feature 1.

5. The support layer includes a ceramic material. The composite film according to feature 1.

6. The support layer comprises at least two of the following: polysulfone (PSf), polyethersulfone (PES), polyvinylidene fluoride (PVDF), and ceramic material. The composite film according to feature 1.

7. The carbon dioxide selective layer includes a silicone polymer. The composite film according to feature 1.

8. The aforementioned silicone polymer contains polydimethylsiloxane (PDMS). The composite film according to feature 7.

9. The carbon dioxide selective layer contains a polyacetylene-derived polymer. The composite film according to feature 1.

10. The polyacetylene-derived polymer includes poly(1-trimethylsilyl-1-propyne) (PTMSP). The composite film according to feature 9.

11. The carbon dioxide selective layer comprises a polyolefin polymer. The composite film according to feature 1.

12. The aforementioned polyolefin polymer contains polymethylpentene (PMP). The composite film according to feature 11.

13. The carbon dioxide selective layer contains a fluoropolymer. The composite film according to feature 1.

14. The fluoropolymer includes polytetrafluoroethylene (PTFE). The composite film according to feature 13.

15. The carbon dioxide selective layer comprises at least one of the following: a silicone polymer, a polyolefin polymer, a polyacetylene-derived polymer, or a fluoropolymer. The composite film according to feature 1.

16. The carbon dioxide selective layer is the first carbon dioxide selective layer, The composite film also includes a second carbon dioxide selective layer that can be distinguished from the first carbon dioxide selective layer. The composite film according to feature 1.

17. The second carbon dioxide selective layer comprises at least one of a silicone polymer, a polyolefin polymer, a polyacetylene-derived polymer, or a fluoropolymer. The composite film according to feature 16.

18. The carbon dioxide selective layer has a thickness of 50 micrometers or less. The composite film according to feature 1.

19. The carbon dioxide selective layer has a thickness of 20 micrometers or less. The composite film according to feature 1.

20. The carbon dioxide selective layer has a thickness of 10 micrometers or less. The composite film according to feature 1.

21. The carbon dioxide selective layer has selectivity for the dissolved carbon dioxide gas in the aqueous solution compared to other dissolved gases in the aqueous solution. The composite film according to feature 1.

22. The support layer has a hollow cylindrical structure, The first surface is the inner surface of the hollow cylindrical structure, The second surface is the outer surface of the hollow cylindrical structure. The composite film according to feature 1.

23. The inner diameter of the hollow cylindrical structure is 2 millimeters or less. The composite film according to feature 22.

24. The outer diameter of the hollow cylindrical structure is 3 millimeters or less. The composite film according to feature 22.

25. The support layer has a porous structure. The composite film according to feature 1.

26. The carbon dioxide selective layer partially fills the porous structure of the support layer and terminates at a predetermined depth between the first and second surfaces of the support layer. The composite film according to feature 25.

27. The aqueous solution contains seawater The composite film according to feature 1.

28. The concentration of carbon dioxide in the aqueous solution is parts per million (ppm) or more. The composite film according to feature 1.

29. The aqueous solution has a pH value of 4 or higher. The composite film according to feature 27.

30. A method for separating dissolved carbon dioxide gas from an aqueous solution, The step of obtaining the aqueous solution, The steps include bringing the aqueous solution into contact with the first surface of the composite film, Equipped with, The composite film is A support layer having the first surface and the second surface on the opposite side, A carbon dioxide selective layer disposed on the first surface, It has, The carbon dioxide selective layer is configured to come into contact with an aqueous solution containing dissolved carbon dioxide, and to selectively transport the dissolved carbon dioxide from the aqueous solution to the second surface via the support layer. This method is A step of collecting the dissolved carbon dioxide gas from the second surface of the composite film. A method characterized by further comprising the following.

31. Prior to the step of contacting the aqueous solution, the step of acidifying the aqueous solution containing dissolved inorganic carbon to convert the dissolved inorganic carbon into dissolved carbon dioxide. The method according to 30, further comprising the following:

32. The support layer contains polysulfone (PSf) The method according to the present invention, characterized by the present invention.

33. The support layer contains polyethersulfone (PES) The method according to the present invention, characterized by the present invention.

34. The support layer contains polyvinylidene fluoride (PVDF). The method according to the present invention, characterized by the present invention.

35. The support layer includes a ceramic material. The method according to the present invention, characterized by the present invention.

36. The carbon dioxide selective layer includes a silicone polymer. The method according to the present invention, characterized by the present invention.

37. The aforementioned silicone polymer contains polydimethylsiloxane (PDMS). The method according to the feature of 36.

38. The carbon dioxide selective layer contains a polyacetylene-derived polymer. The method according to the present invention, characterized by the present invention.

39. The polyacetylene-derived polymer includes poly(1-trimethylsilyl-1-propyne) (PTMSP). The method according to the feature of 38.

40. The carbon dioxide selective layer comprises a polyolefin polymer. The method according to the present invention, characterized by the present invention.

41. The aforementioned polyolefin polymer contains polymethylpentene (PMP). The method according to 40, characterized by...

42. The carbon dioxide selective layer contains a fluoropolymer. The method according to the present invention, characterized by the present invention.

43. The fluoropolymer includes polytetrafluoroethylene (PTFE). The method according to 42, characterized by the features described above.

44. The carbon dioxide selective layer is the first carbon dioxide selective layer, The composite film also includes a second carbon dioxide selective layer that can be distinguished from the first carbon dioxide selective layer. The method according to the present invention, characterized by the present invention.

45. The carbon dioxide selective layer has a thickness of 50 micrometers or less. The method according to the present invention, characterized by the present invention.

46. The carbon dioxide selective layer has selectivity for the dissolved carbon dioxide gas in the aqueous solution compared to other dissolved gases in the aqueous solution. The method according to the present invention, characterized by the present invention.

47. The support layer has a hollow cylindrical structure, The first surface is the inner surface of the hollow cylindrical structure, The second surface is the outer surface of the hollow cylindrical structure. The method according to the present invention, characterized by the present invention.

48. The inner diameter of the hollow cylindrical structure is 2 millimeters or less. The method according to feature 47.

49. The outer diameter of the hollow cylindrical structure is 3 millimeters or less. The method according to feature 47.

50. The support layer has a porous structure. The method according to the present invention, characterized by the present invention.

51. The carbon dioxide selective layer partially fills the porous structure of the support layer and terminates at a predetermined depth between the first and second surfaces of the support layer. The method according to 50, characterized by...

52. The aqueous solution contains seawater The method according to the present invention, characterized by the present invention.

53. The concentration of carbon dioxide in the aqueous solution is parts per million (ppm) or more. The method according to the present invention, characterized by the present invention.

54. The aqueous solution has a pH value of 4 or higher. The method according to 53, characterized by...

55. A system for separating dissolved carbon dioxide gas from an aqueous solution, A contactor module having a composite film that separates the first chamber from the second chamber, Control system and, Equipped with, The composite membrane is configured to selectively transport dissolved carbon dioxide from the aqueous solution in the first chamber from the first chamber to the second chamber. The composite film is A support layer having a first surface and a second surface on the opposite side, A carbon dioxide selective layer disposed on the first surface, It has, The carbon dioxide selective layer is configured to come into contact with the aqueous solution and to selectively transport the dissolved carbon dioxide through the support layer. The control system is A step of adjusting the pH value of the aqueous solution, A step of supplying the aqueous solution with the adjusted pH value to the first chamber of the contactor module so that the aqueous solution flows through the first chamber from the first end to the second end on the opposite side of the contactor module, A step of adjusting the partial pressure in the second chamber of the contactor module, A step of evaluating the concentration of carbon dioxide gas collected from the second chamber of the contactor module, It is configured to perform actions that include A system characterized by the following features.

56. The carbon dioxide selective layer includes a silicone polymer. The system according to claim 55, characterized in that it is the same as described above.

57. The carbon dioxide selective layer comprises a polyolefin polymer. The system according to claim 55, characterized in that it is the same as described above.

58. The carbon dioxide selective layer contains a polyacetylene-derived polymer. The system according to claim 55, characterized in that it is the same as described above.

59. The carbon dioxide selective layer contains a fluoropolymer. The system according to claim 55, characterized in that it is the same as described above.

60. The support layer has a hollow cylindrical structure, The first surface is the inner surface of the hollow cylindrical structure, The second surface is the outer surface of the hollow cylindrical structure. The system according to claim 55, characterized in that it is the same as described above.

61. The support layer has a porous structure. The system according to claim 55, characterized in that it is the same as described above.

62. The carbon dioxide selective layer partially fills the porous structure of the support layer and terminates at a predetermined depth between the first and second surfaces of the support layer. The system described in claim 61.

63. The aqueous solution contains seawater The system according to claim 55, characterized in that it is the same as described above.

64. Means for providing a driving force between the first surface and the second surface of the composite film so that the dissolved carbon dioxide gas is selectively transported from the aqueous solution to the second surface of the support layer through the carbon dioxide selective layer. The system according to claim 55, further comprising the above.

65. The means that provides a driving force between the first surface and the second surface of the composite film includes a pressure difference between the first surface and the second surface of the composite film. The system described in claim 64.

66. The aforementioned pressure difference is 10 4 It is greater than Pascal. The system according to 65, characterized in that it is as described above.

67. A liquid inlet configured to introduce the aqueous solution into the first surface of the composite membrane, A liquid outlet configured to receive liquid residue, A pump configured to pass the aqueous solution from the liquid inlet to the liquid outlet, A gas outlet configured to collect the permeated carbon dioxide gas, The system according to claim 55, further comprising the above.

68. Multiple contactor modules Equipped with, Each contactor module has multiple composite films, The multiple contactor modules are connected in series with one another. The system according to claim 55, characterized in that it is the same as described above.

69. Multiple contactor modules Equipped with, Each contactor module has multiple composite films, The plurality of contactor modules are connected in parallel to one another. The system according to claim 55, characterized in that it is the same as described above.

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