WO2021042229A1

WO2021042229A1 - Gas-liquid exchange system and method of using the same

Info

Publication number: WO2021042229A1
Application number: PCT/CN2019/103937
Authority: WO
Inventors: Alexey IZGORODIN; Ivan IZGORODIN
Original assignee: Etp International Company Limited
Priority date: 2019-09-02
Filing date: 2019-09-02
Publication date: 2021-03-11

Abstract

A gas-liquid exchange system (100) contains a gas (20) and a liquid (25). The gas-liquid exchange system (100) includes a chamber having a first inlet for introducing a stream of a gas (20) into the chamber; a first outlet in fluid communication with the first inlet, through which the gas exits the chamber; a second inlet for directing a stream of a liquid (25) into the chamber; a second outlet in fluid communication with the second inlet, through which the liquid exits the chamber; and a membrane (5) within the chamber for gas-liquid contact. The membrane (5) divides the chamber into at least a gas portion (10) and a liquid portion (15), the gas portion (10) receiving the gas (20) from the first inlet and discharging the gas (20) via the first outlet, and the liquid portion (15) receiving the liquid (25) from the second inlet and discharging the liquid (25) via the second outlet. The membrane (5) contains the liquid (25) within the liquid portion (15) and that the membrane (5) at least partly defines a flow path for the gas (20) within the chamber, while the gas (20) and the liquid (25) are in contact at the membrane (5) and at least a portion of an ingredient in one of the gas (20) and the liquid (25) enters into the other of gas (20) and the liquid (25) upon the contact. A method for exchanging an ingredient between a gas (20) and a liquid (25) is also described.

Description

GAS-LIQUID EXCHANGE SYSTEM AND METHOD OF USING THE SAME

Field of the Invention

The present invention generally relates to a gas-liquid exchange system.

Background of the Invention

Systems for capture and/or separation of gases and liquids are important industrial applications that may be used for removal of, for example, SO ₂, CO ₂, CO, NO _x from flue and off gases, removal of water, CO ₂ and H ₂S from natural gas, and desulfurization of biogas, etc.

Current industrial gas-liquid exchange systems can be classified into differential systems (e.g. packed columns, bubble columns and spray towers etc. ) , where mass transfer occurs within the entire length of the equipment, and stage-wise systems (e.g. plate columns) , where mass transfer occurs only in a part of the volume at each stage. Although liquid absorbency is a relatively efficient and mature technology, it still faces several crucial problems including, for example, a large footprint, high energy consumption, corrosion, foaming and solvent loss through degradation and entrapment. For example, packed bed absorption columns often require large diameter and height in order to provide the desired purification. This puts significant constrains on many potential applications of gas-liquid exchange systems (e.g. transportation emission control) where size and weight constraints make their use both technically and economically impractical.

In view of the above, there exists a need to provide a system which provides efficient gas-liquid exchange and a need to reduce size and weight constraints at the same time.

Summary of the Invention

An aspect of the present invention provides a gas-liquid exchange system for containing a gas and a liquid. The gas-liquid exchange system includes a chamber having a first inlet for introducing a stream of a gas into the chamber; a first outlet in fluid communication with the first inlet, through which the gas exits the chamber; a second inlet for directing a stream of a liquid into the chamber; a second outlet in fluid communication with the second inlet, through which the liquid exits the chamber; and a membrane within the chamber for gas-liquid contact. The membrane divides the chamber into at least a gas portion and a liquid portion, the gas portion receiving the gas from the first inlet and discharging the gas via the first outlet, and the liquid portion receiving the liquid from the second inlet and discharging the liquid via the second outlet. The membrane contains the liquid within the liquid portion and that the membrane at least partly defines a flow path for the gas within the chamber, while the gas and the liquid are in contact at the membrane and at least a portion of an ingredient in one of the gas and the liquid enters into the other of gas and the liquid upon the contact.

Another aspect of the present invention provides a method of conducting gas-liquid exchange. The method includes the steps of: introducing a stream of a gas into a chamber comprising a membrane, where the membrane divides the chamber into at least a gas portion and a liquid portion with the gas portion receiving the gas, and where the membrane defines a flow path for the gas; introducing a stream of a liquid to the liquid portion of the chamber, where the membrane contains the liquid within the liquid portion; effecting contact between the gas and the liquid at the membrane, such that at least a portion of an ingredient in one of the gas and the liquid enters into the other of the gas and the liquid upon the contact; and discharging the gas out of the chamber, and discharging the liquid out of the chamber.

Without intending to be limited by theory, it is believed that the present invention utilizes a membrane having a high contact surface area per volume as the interface, and thus sufficient gas-liquid contact takes place to facilitate exchange therebetween. Moreover, due to the efficiency of the membrane as the contact interface and given the pliability and flexibility of the membrane material, the gas-liquid system according to the present invention may be designed to accommodate small space and/or weight constraints while still allowing for sufficient gas-liquid contact. Accordingly, the present invention is customization-friendly, and is potentially-applicable to a range of industrial and civil settings, such as a factory, a power plant, a building, a house, a vehicle, a maritime vehicle, etc.

The present invention is also potentially-applicable to synthetic fuel production, chemical production, carbon dioxide and/or water capture from air, electrochemical/chemical deposition and stripping processes, etc.

Brief Description of the Drawings

It will be convenient to further describe the present invention with respect to the accompanying drawings that illustrate possible arrangements of the invention. Other arrangements of the invention are possible and consequently, the particularity of the accompanying drawings is not limiting and is not to be understood as superseding the generality of the preceding description of the invention.

Figure 1 schematically shows a cross-section of a gas-liquid exchange system according to an embodiment of the present invention;

Figure 2 schematically shows a cross-section of a gas-liquid exchange system according to an embodiment of the present invention, illustrating gas-to-liquid mass transfer and liquid-to-gas mass transfer respectively;

Figure 3 schematically shows a cross-section of a gas-liquid exchange system according to an embodiment of the present invention, wherein the gas and liquid flows may be independently organized;

Figure 4 schematically shows a cross-section of a gas-liquid exchange system according to an embodiment of the present invention, illustrating various arrangements of the membrane and a matrix;

Figure 5 schematically shows a cross-section of a gas-liquid exchange system according to an embodiment of the present invention, illustrating various configurations of the matrix in relation to the membrane;

Figure 6 schematically shows a cross-section of a gas-liquid exchange system according to an embodiment of the present invention, wherein the membrane includes a layer of a substrate;

Figure 7 schematically shows a cross-section of a gas-liquid exchange system according to an embodiment of the present invention, illustrating various configurations of the substrate in relation to the membrane;

Figure 8 schematically shows a perspective view of an embodiment of the membrane according to the present invention;

Figure 9 schematically shows an embodiment of a gas-liquid exchange system for removal of carbon dioxide; and

Figure 10 schematically shows a setup of an electrolysis system incorporating a gas-liquid exchange system according to an embodiment of the present invention.

The drawings and figures herein are for reference only and are not necessarily drawn to scale.

Detailed Description of the Invention

Unless otherwise noted, all measurements, weights, lengths etc. are in metric units, and all temperatures are in degrees Celsius. It is understood that unless otherwise specifically noted, the materials compounds, chemicals, etc. described herein are typically commodity items and/or industry-standard items available from a variety of suppliers and sources worldwide.

As use herein, the term “dry ionic liquid” refers to an ionic liquid that is substantially anhydrous.

The term “gas-liquid exchange” , as used herein, means any transfer and/or conversion of a chemical from a gas phase into a liquid phase as well as transfer and/or conversion of a chemical from the liquid phase into the gas phase. It may include any possible process occurring during contact between a gas and a liquid.

The term “ionic liquid” refers to a salt containing any of a variety of anions or cations that is reasonably fluid under ambient conditions. The salt may contain monovalent or polyvalent anions or cations. In addition, an ionic liquid may be a single salt or a mixture of salts.

The term “membrane” , as used herein, refers to a three-dimensional network of polymers, fibers or a hydrogel, and used in the gas-liquid exchange system of the present invention for separating the liquid and gas phases.

The term “membrane density” is defined as the proportion of the mass of a membrane excluding the mass of the liquid to the total mass of the membrane mass including the mass of the liquid present in a given volume of the membrane during operation.

The term “membrane force density” is defined as the number of groups that enable presence of attractive intermolecular forces in a given volume of a membrane during operation.

The term “ (meth) acrylic” as used herein refers to either “acrylic” or “methacrylic” .

The term “organic solvent” as used herein generally refers to a non-aqueous solvent, and/or to a solvent containing one or more organic compounds.

The term “volatile organic compound” , as used herein, refers to an organic compound that has a vapor pressure equal to or higher than 0.01 kPa or an equivalent volatility in the particular conditions of use at 20℃. Such an organic compound often has less than twelve carbon atoms in its chain and may contain other elements such as oxygen, fluoride, chlorine, bromine, sulphur and nitrogen.

In one embodiment, the membrane is a three-dimensional network including a material selected from the group of a polymer, a fiber and a combination thereof, where the membrane contains the liquid within the liquid portion through an intermolecular attractive force. Without intending to be limited by theory, it is believed that such a system provides a new and inventive approach to gas-liquid exchange, by incorporating a membrane containing materials that have not been previously used in gas-liquid exchange systems. Some of known gas-liquid exchange systems utilize membrane materials which are very dense, mostly uniform and have limited water and/or solvent content within its structure, such that a membrane selectively dissolves components of a liquid/gas or does not allow for a significant portion of liquid to be present. Such materials generally have low rates of mass transfer. On the other hand, whilst thinner membranes may perform better in terms of mass transfer rate, they suffer from poor mechanical properties. Furthermore, the diffusion through conventional membranes often depends on the presence of water and/or other solvents within the membrane structure, and is thus temperature-sensitive. Subject to the temperature limits imposed by the water and/or other solvents within the membrane structure, conventional membranes may not be able to function properly across a broad temperature range.

Other known gas-liquid exchange systems utilize materials which are porous in nature with repulsive forces to prevent liquid from flowing into the gas phase. Such materials by nature have limited open surface area with only small channels available for gas to diffuse through and contact with liquid. The channels have to be very small to maintain liquid/gas separation. Such systems are not able to work over wide ranges of differential pressure between gas and liquid. Higher pressure on the gas side may result in gas flow through the structure of the membrane. Additionally, these materials have poor stability over time. Generally, the small channels will be filled with liquid over time that significantly reduces mass transfer between gas and liquid.

In the present invention, the use of attractive forces allows for a membrane of a solid-like structure that can maintain phase separation at various differential pressures between gas and liquid.

Additionally, such a structure can operate effectively across a broad range of liquid types and chemical activities over a long time period, with sufficient durability and strength. Another advantage of the present invention is the ability to create very large open contact area between gas and one or more active component of the liquid, which in some cases may reach close to 100%of total membrane area.

The gas to be introduced to the gas-liquid exchange system of the present invention may come from a source selected from the group of combustion, ventilation, manufacturing, air and a combination thereof. The gas may include, for instance, emission from a source selected from the group of a power plant, a manufacturing facility, a waste incinerator, a fireplace, an oven, a boiler, a smelter, a furnace, a steam generator, a vehicle and a combination thereof. As discussed above, due to the high efficiency, pliability and flexibility of the membrane, the gas-liquid exchange system of the present invention may be applicable to a variety of settings.

In one embodiment, the ingredient that is exchanged between the gas and the liquid is selected from the group of an organic compound, a metal, an inorganic compound and a combination thereof. Specifically, the ingredient may be selected from the group of SO _x, HCl, CO ₂, NH ₃, H ₂S, H ₂O, acid gas, formic acid, H ₂, O ₃, NO _x, Hg vapor, Cl ₂, I ₂, F ₂, CO, CH ₄, CH ₂O, benzene, toluene, Pb, Rn, HF, As, Se, Cd, ethylbenzene, xylene (o-, m-and p-) , pentane (i-, n-, 2M-, 3M-, MC-) , butane (i-, n-) , hexane (n-, MC-) , trans-2-pentene, trans-2-butene, 2-Methylpentane, 3-Methylpentane, Methylcyclopentane, Ethane, Propane, 2, 3-Dimethylbutane, 2, 3-dimethylpentane, Propylene, cyclohexane, dichloromethane, acrolein, ethene, MTBE, formaldehyde, acetone, isopropyl alcohol, carbon tetrachloride, carbon disulfide, vinyl chloride, trichloro ethylene, tetrachloroethylene, ethyl acetate, methanol, methylene chloride and a combination thereof.

In one embodiment, the liquid to be introduced to the gas-liquid exchange system of the present invention is selected from the group of a polar solvent, a non-polar solvent, an ionic liquid and a combination thereof. Without intending to be limited by theory, the membrane of the present invention not only allows a wide range of solvents to be within the membrane, it is also of sufficient strength and/or durability to withstand harsh conditions imparted by the liquid used, such as high or very high acidity, alkalinity or extreme temperatures. As such, and as will be further described below, the membrane according to the present invention allows for use of a variety of different solvents.

Such a liquid may be acidic, alkaline, or neutral, optionally including an oxidizing agent. Specifically, the liquid may be selected from the group of water, chlorine, chlorine dioxide, hydrogen peroxide and a choice of photolyzed chlorine, chlorine dioxide and hydrogen peroxide, alkali metal chloride, alkali metal hydroxide, carbonate and bicarbonate, an aqueous solution of an alkaline or alkaline earth hydroxide, an alkaline earth oxide, an alkaline or alkaline earth carbonate, lime (CaO) , limestone, calcium carbonate (CaCO ₃) , an aqueous solution selected from the group of water soluble oxidizing salts, water soluble halide containing salts, NaClO ₂, NaClO ₃, H ₂O ₂, KMnO ₄, Ca (OCl) ₂, and a combination thereof.

In one embodiment, at least a portion of the ingredient in one of the gas and the liquid enters into the other of the gas and the liquid by way of a mechanism selected from the group of absorption, a chemical reaction and a combination thereof. A person skilled in the art will appreciate that the present invention also contemplates other mechanisms by which a component in one of the gas and liquid may be transferred into the other of the gas and liquid upon gas-liquid contact.

In another embodiment, the membrane has a membrane density of from about 0.1%to 99.9%; or from about 1%to 99%; or from about 10%to about 75%; or from about 20%to about 50%.

In a further embodiment, the membrane is disposed over a structure selected from the group of a substrate, a mould, a matrix and a combination thereof, to further enhance the functionalities of the membrane. For instance, the membrane may be arranged on a substrate for additional support and/or strength.

The structure may contain a material selected from the group of felt, fabric, netting, mesh, plastic, metal, glass, ceramic, carbon fiber and a combination thereof. Such membrane forms may be formed by methods well-known in the art and are available as commodity items from, for example, Filtertek Inc. 11411 Price Road, Hebron, Illinois 60034-8936 (http: //filtertek. azurewebsites. net/) ; ZOLTEK Corporation, 3101 McKelvey Road, Bridgeton, MO 63044 (https: //zoltek. com) ; and Ceramaterials, 226 Route 209, Port Jervis, NY 12771 ( https: //ceramaterials. com) .

In one embodiment, the membrane is disposed over the structure in such a manner that at least a portion of the structure is not covered by the membrane. In another embodiment, the structure includes at least one pore that is not filled by the membrane. This may be beneficial in creating channels for liquid or gas to flow during operation. This may also provide various mechanical benefits during assembly, in that the membranes may be combined with other components of the overall assembly in various ways without restricting the flow of liquid and/or gas. Thus, a device with very high contact surface area in a given volume can be created.

In a further embodiment, the structure contains a micro structured material having a pore size of about 0.01 to about 2000 microns; or about 1 to about 500 microns; or about 10 to about 100 microns. In one embodiment, the membrane includes a plurality of individual pieces that are not interconnected with one another. This may occur for example in a honeycomb structure or in structures where pores are not interconnected with each other. This may provide the overall assembly with beneficial mechanical properties (e.g., increased flexibility or rigidity, ability to withhold significant differential pressure, ease of assembly, ease of creating air-tight seal between gas and liquid phase in the assembly, etc. ) . In some cases it may be advantageous for the structure to have at least a portion to be in direct contact with the gas and/or liquid, for the purpose of, for instance, reducing resistance to gas-liquid mass transfer etc.

In another embodiment, the membrane is configured to comprise a plurality of tubes; or hollow tubes, so as to further increase the contact surface between the gas and the liquid

In one embodiment, at least one of a length, width and diameter of the membrane is based on a factor selected from the group of flow rate, the amount of mass transfer exchange required, the system lifetime, and a combination thereof.

In another embodiment, the membrane includes a first thickness and a second thickness, the first thickness being different from the second thickness, for providing an uneven surface of the membrane. Doing so may further increase the contact surface between the gas and the liquid, thereby facilitating mass transfer therebetween. In a further embodiment, the membrane is from about 0.5 μm to about 2000 μm thick; or from about 4 μm to about 500 μm thick; or from about 10 μm to about 150 μm thick; or from about 25 μm to about 100 μm thick.

In one embodiment, the membrane contains a material selected from the group of a linear polymer, a branched polymer, an interpenetrating polymer network and a combination thereof. In another embodiment, the membrane contains a monomer selected from the group of a (C1-16) alkylacrylate, a (C1-16) alkyl methacrylate, a (C1-12) alkylmaleic acid ester, a (C1-12) alkyl (C6-12) aryl urethane oligomer, a (C1-12) alkyl allyl urethane oligomer, a (C1-12) alkyl urethaneacrylate oligomer, a fluoro (C1-16) alkylacrylate, a fluoro (C1-16) alkyl methacrylates, and a combination thereof.

In one embodiment, the membrane contains a polymer selected from the group of an oleophobic polymer, a water-insoluble polymer, and a combination thereof. Examples of such materials include, without limitation, oleophilic polyethylene terephthalate, polytetrafluoroethylene, fluorinated polyesters, fluorinated urethane, polyurethane, nylon, polyethersulfone, polyvinylidene difluoride, sulfone polymer (e.g. polysulfone, polyethersulfone, or polyarylsulfone) and polyvinylidene fluoride. Suppliers include Merck KGaA, Darmstadt, Germany (https: //www. sigmaaldrich. com) .

In another embodiment, the membrane contains a polymer selected from the group of a poly (N-alkyl (meth) acrylamide) ; a poly (N-vinylalkylamide) ; a poly (N-vinylpyrrolidone) ; a poly (2-alkyl-2-oxazoline) ; a polyvinyl alkyl ether; a copolymer of polyethylene oxide and polypropylene oxide; a poly (oxyethylene vinyl ether) ; a cellulose derivative; and a copolymer of the above polymers; a N-alkyl (meth) acrylamide; a N-vinylalkylamide; a vinyl alkyl ether; ethylene oxide and propylene oxide; a 2-alkyl-2-oxazoline; and a combination thereof. Suppliers include Merck KGaA, Darmstadt, Germany ( https: //www. sigmaaldrich. com) .

Specifically, the poly (N-alkyl (meth) acrylamide) may be selected from the group of poly (N-isopropyl (meth) acrylamide) , poly (N-n-propyl (meth) acrylamide) , poly (N-methyl (meth) acrylamide) , poly (N-ethyl (meth) acrylamide) , poly (N-n-butyl (meth) acrylamide) , poly (N-isobutyl (meth) acrylamide) , poly (N-t-butyl (meth) acrylamide) and a combination thereof; the poly (N-vinylalkylamide) may be selected from the group of poly (N-vinylisopropylamide) , poly (N-vinyl n-propylamide) , poly (N-vinyl n-butylamide) , poly (N-vinylisobutylamide) , poly (N-vinyl-t-butylamide) and a combination thereof; the poly (2-alkyl-2-oxazoline) may be selected from the group of poly (2-ethyl-2-oxazoline) , poly (2-isopropyl-2-oxazoline) , poly (2-n-propyl-2-oxazoline) and a combination thereof; the polyvinyl alkyl ether may be selected from the group of polyvinyl methyl ether, polyvinyl ethyl ether and a combination thereof; the cellulose derivative may be selected from the group of methyl cellulose, ethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose and combination thereof; the N-alkyl (meth) acrylamide may be selected from the group of N-isopropyl (meth) acrylamide, N-n-propyl (meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-n-butyl (meth) acrylamide, N-isobutyl (meth) acrylamide, N-t-butyl (meth) acrylamide and a combination thereof; the N-vinylalkylamide may be selected from the group of N-vinylisopropylamide, N-vinyl n-propylamide, N-vinyl n-butylamide, N-vinylisobutylamide, N-vinyl-t-butylamide and a combination thereof; the vinyl alkyl ether may be selected from the group of vinyl methyl ether, vinyl ethyl ether and a combination thereof; and the 2-alkyl-2-oxazolines may be selected from the group of 2-ethyl-2-oxazoline, 2-isopropyl-2-oxazoline, 2-n-propyl-2-oxazoline and a combination thereof. Suppliers include Merck KGaA, Darmstadt, Germany ( https: //www. sigmaaldrich. com) .

In one embodiment, the membrane contains a material selected from the group of a homopolymer, a copolymer, a cross-linked polymer, a polymer with alternating units, a polymer with random units, a block polymer and a combination thereof. Examples of such a material include, without limitation, nylon, polyester, PVC, polyethen, glycogen, starch, melamine formaldehyde resin, thermoplastic and thermosetting materials, etc. Suppliers include Merck KGaA, Darmstadt, Germany ( https: //www. sigmaaldrich. com) .

In another embodiment, the membrane contains a filler selected from the group of a reinforcing fiber (e.g., steel fibers, glass fibers, synthetic fibers and natural fibers, etc. ) , a conductive filler (e.g. nickel, coated nickel, graphite, nickel coated graphite, etc. ) , a coupling agent (e.g., organosilanes) , a nanoclay (e.g. montmorillonite, bentonite, kaolinite, hectorite, and halloysite) , a nanoparticle (ceramics, aluminium oxide, copper (II) oxide, silicon dioxide, zinc oxide, titanium oxide, silicate, polymers, glass-ceramics, composite materials, metal, carbides (SiC) , nitrides (Aluminum nitrides, Silicon nitride) , metals (Al, Cu) , non-metals (graphite, carbon nanotubes, layered structures, etc) , a polymer (e.g., polyethylene, polypropylene fibers, etc. ) and a combination thereof. Suppliers include Automated Dynamics, 2 Commerce Park Drive, Niskayuna, NY 12309, USA (http: //www. automateddynamics. com) ; Oerlikon Metco Switzerland, Churerstrasse 120, 8808

Switzerland (https: //www. oerlikon. com) ; Gelest, Inc., 11 East Steel Rd., Morrisville, PA 19067, USA (https: //www. gelest. com) ; and Merck KGaA, Darmstadt, Germany (https: //www. sigmaaldrich. com) .

Specifically, the reinforcing fiber may be selected from the group of boron, carbon, fibrous mineral, glass, poly paraphenylene terephthalamide, and a combination thereof; the conductive filler may be selected from the group of aluminum powder, carbon fiber, graphite, and a combination thereof; the coupling agent may be selected from the group of a silane, a titanite, and a combination thereof; the nanoclay may be selected from the group of bentonite, halloysite, and a combination thereof; the nanoparticle may be selected from the group of silicon dioxide, titanium dioxide, and a combination thereof; and the polymer chain may be selected from the group of Poly (vinyl alcohol) , Carboxymethyl cellulose, and a combination thereof. Suppliers include Merck KGaA, Darmstadt, Germany ( https: //www. sigmaaldrich. com) .

In one embodiment, the membrane contains an ionically crosslinked polymer; or an ionically crosslinked elastomer; or an ionically crosslinked polyisoprene elastomer. Examples include poly- (allylamine hydrochloride) , pyrophosphate, tripolyphosphate, polyvinylbenzene chloride, polyvinylimidazole, polyethyleneimine, polyallyl chloride. Suppliers include Merck KGaA, Darmstadt, Germany ( https: //www. sigmaaldrich. com) .

Another aspect of the present invention relates to a device for removal of an ingredient from a gas including the gas-liquid exchange system according to the present invention. Specifically, the gas-liquid system of the present invention may be used in a device for discharging an exhaust gas from a source selected from the group of a power plant, a manufacturing facility, a waste incinerator, a fireplace, an oven, a boiler, a smelter, a furnace, a steam generator, a car, a bus, a truck, a ship and a combination thereof.

A further aspect of the present invention relates to a device for replenishing an ingredient in a liquid to a gas including the gas-liquid exchange system according to the present invention. For instance, the gas-liquid exchange system according to the present invention may be used in an electrolysis system for the purpose of humidity replenishment. To that end, the gas-liquid exchange system of the present invention may be designed as a replaceable cartridge.

In one embodiment, an air purification and/or exchange system for a building is provided, such air purification and/or exchange system including the gas-liquid exchange system according to the present invention.

In another embodiment, a device for vehicle exhaust emissions is provided, the device may include a gas-liquid exchange system according to the present invention.

A further embodiment of the present invention provides a ventilation system including a gas-liquid exchange system according to the present invention.

Another aspect of the present invention relates to the use of a gas-liquid exchange system according to the present invention for an operation selected from the group of: flue gas and off gas treatment; acid gas removal from a Natural Gas and fuel mixture; indoor air purification; CO ₂ recovery; mercury removal; desulfurization of biogas; palm oil deacidification; iodide oxidation; olefin/paraffin separation; oxygenation/deoxygenation; Gas humidity control; volatilization of a product; and a combination thereof.

In one embodiment, the gas-liquid exchange system of the present invention may be provided in a location selected from the group of an exhaust pipe, a flue gas stack, a propelling nozzle, and a combination thereof. Without intending to be limited by theory, it is believed that such a location can potentially trap and remove undesirable gasses and/or liquids from the exhaust stream before they escape into the environment. Furthermore, as these locations tend to be of a higher temperature, the kinetics of the gas-liquid exchange or other mass transfer may occur at an increased rate at such a location without the need for additional energy input.

Another aspect of the present invention provides a method of conducting gas-liquid exchange. The method includes the steps of: introducing a stream of a gas into a chamber comprising a membrane, wherein the membrane divides the chamber into at least a gas portion and a liquid portion with the gas portion receiving the gas, and wherein the membrane defines a flow path for the gas; introducing a stream of a liquid to the liquid portion of the chamber, wherein the membrane contains the liquid within the liquid portion; effecting contact between the gas and the liquid at the membrane, such that at least a portion of an ingredient in one of the gas and the liquid enters into the other of the gas and the liquid upon the contact; discharging the gas out of the chamber, and discharging the liquid out of the chamber.

In one embodiment, the method further includes applying the membrane in a liquid form over a structure selected from the group of a substrate, a mould, a matrix and a combination thereof. As discussed above, this is to add additional functionality to the membrane, such as strength and/or durability etc. Specifically, the applying of the membrane may be facilitated by an organic solvent selected from the group of an alkane, a ketone, an ester, an ether, an alcohol and a combination thereof. In one embodiment, the organic solvent is selected from the group of heptane, ethyl acetate, butyl acetate, isoamyl acetate, dioctyl adipate, acetone, methyl ethyl ketone, methyl isobutyl ketone, isopropanol, diethyl ether, mineral spirit, petroleum distillate, and a combination thereof.

In another embodiment, the applying of the membrane is conducted with a stabilizing agent, wherein the stabilizing agent is from about 5 wt%to about 50 wt%, or from about 15 wt%to about 25 wt%, by weight of the membrane. The stabilizing agent may be selected from, for instance, the group of deionized water, demineralized water and a combination thereof.

In one embodiment, a surface of the structure is treated before the formation of the membrane, for easy application of the membrane and/or to add additional functionality to the structure.

In another embodiment, the method further includes synthesizing the membrane by polymerization of a molecule selected from a monomer, an oligomer and a combination thereof. In a further embodiment, the method as described herein, further including synthesizing the membrane based on a polymer.

In one embodiment, the polymerization is conducted with a cross-linking agent selected from the group of N, N-′bisacrylamide, N, N′-bis (acryloyl) -cystamine, ethylenediamine, 1, 3-propanediamine, 1, 3-propanedithiol, dithiothreitol, dithioerythritol, 1, 5-pentanediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, propylenediamine, di (aminomethyl) ether, 1, 8-diamino-4- (aminomethyl) octane, xylylenediamine, hydroquinone, bisphenol A, bisphenol sulfone, 1, 4-butanedisulfinic acid, benzenedisulfinic acid, thioethanolamine, p-aminothiophenol, and butylenediamine, ethyleneglycol dimethacrylate, trimethylolpropane triacrylate, hexamethyleneglycol dimethacrylate, glycerol α, α’-diallylether, n-methylol acrylamide, vinylbenzene chloride, allyl chloride, gloxal, polyvinyl alcohol, polyethyleneimine, 1-vinylimidazole, hexadiene, tetraethylene glycol dimethacrylate, divinyl benzene, 1, 6-diaminohexane, p-phenylenediamine, ethylene glycoldi (meth) acrylate, propylene glycoldi (meth) acrylate, N, N′-methylenebis (meth) acrylamide, tolylene diisocyanate, divinylbenzene, and polyethylene glycoldi (meth) acrylate; glutaraldehyde; polyvalent alcohol; polyvalent amine; polyvalent carboxylic acid; a metal ion, and a combination thereof.

Specifically, the metal ion may be selected from the group of a calcium ion, a zinc ion and a combination thereof.

In one embodiment, effecting contact between the gas and the liquid at the membrane includes subjecting one or both of the gas and the liquid to a stimulus for promoting mass transfer selected from the group of pressure, temperature, electric or magnetic field, light, sound, ultrasonic wave, pH, solvent composition, ionic strength, molecular species and a combination thereof.

In one embodiment, effecting contact between the gas and the liquid at the membrane includes applying a first pressure to the gas and applying a second pressure to the liquid, such that the first pressure is different from the second pressure. In another embodiment, effecting contact between the gas and the liquid at the membrane includes controlling a flow rate of the gas and a flow rate of the liquid, such that the flow rate of the gas is different from the flow rate of the liquid. In a further embodiment, effecting contact between the gas and the liquid at the membrane includes controlling a direction of the gas and a direction of the liquid, such that at least one of the gas and the liquid flows in a direction perpendicular to the membrane. Using differential stimuli to the gas and liquid respectively accommodates different properties of the gas and the liquid, and thus could be advantageous in cases where the gas/liquid used is particularly sensitive to a certain stimulus.

In one embodiment, effecting contact between the gas and the liquid at the membrane takes place in a device for discharging a exhaust gas from a source selected from a power plant, a manufacturing facility, a waste incinerator, a fireplace, an oven, a boiler, a smelter, a furnace, a steam generator, a car, a bus, a truck, a ship and a combination thereof. In another embodiment, effecting contact between the gas and the liquid at the membrane takes place in a location selected from the group of an exhaust pipe, a flue gas stack, a propelling nozzle, and a combination thereof.

In one embodiment, the method further includes, after the contact between the gas and the liquid, effecting gas-liquid exchange between one of the gas and the liquid and a stream of a third fluid, wherein the third fluid is in a gas form or a liquid form, the form of the third fluid being different from the form of the gas or liquid with which the third fluid is in gas-liquid exchange. As such, the present invention contemplates subsequent treatment of the gas and/or the liquid after the initial gas-liquid exchange. For instance, CO ₂ absorbed into the liquid from the gas may be later recovered and commercialized as a secondary product. Furthermore, the present invention contemplates targeted removal of one or more specific components in the gas/liquid at different stages of gas-liquid exchange.

Specifically, the method may further include, after the contact between the gas and the liquid, subjecting one of the gas and the liquid to a treatment selected from the group of oxidation, decarbonation, evaporation, distillation, evacuation, extraction, crystallization, and a combination thereof.

In one embodiment, effecting contact between the gas and the liquid at the membrane includes organizing the gas and the liquid in same or counterflow directions.

In another embodiment, the method further includes, after the contact between the gas and the liquid, effecting additional contact between the gas and the liquid at an additional membrane within the chamber.

In a further embodiment, the method further includes, prior to synthesizing the membrane, determining a membrane force density and a membrane density for the membrane such that the membrane forms gas-liquid interface and withstands differential pressure.

General Description of Gas-Liquid Exchange System

Turning to the figures, Figure 1 schematically illustrates a cross-sectional view of a gas-liquid exchange system 100 according to an embodiment of the present invention. The membrane 5 in this embodiment separates a gas portion 10 from a liquid portion 15. The membrane 5 allows for liquid 25 to be contained within the liquid portion 15 while preventing the liquid 25 from flowing into the gas portion 10 wherein the gas 20 is present. The containing of the liquid 25 by the membrane 5 is achieved by intermolecular attractive forces, due to any known mechanisms. Examples of such forces include, but are not limited to, ion induced dipole forces, ion-dipole forces, hydrogen bonding, van der Waals forces, etc.

Thus, a system 100 for gas-liquid exchange is provided, where the membrane 5 acts as a physical barrier preventing the flow of the liquid 25 into the gas portion 10 while still allowing for contact area between the gas 20 and the liquid 25.

Figure 2 schematically illustrates mass transfer between the gas 20 and the liquid 25 in a gas-liquid exchange system 100 according to an embodiment of the present invention. Specifically, Figure 2A illustrates mass transfer from the gas 20 to the liquid 25, and Figure 2B illustrates mass transfer from the liquid 25 to the gas 20.

Examples of typical operation during mass transfer from the gas 20 to the liquid 25 are described below. It is appreciated that the principles discussed herein are equally-applicable to mass transfer from the liquid 25 to the gas 20.

Molecules of the gas 20 diffuse from the bulk of the gas 20 into the membrane 5 through interaction with the liquid 25 as well as possible interaction with membrane 5 and optionally its other components. Once in contact with the membrane 5, molecules of the gas 20 may form ionic species, remain neutral or form a complex. The mass transfer across the membrane 5 can be via simple diffusion, channel diffusion or facilitated diffusion based on the composition of the membrane 5 and properties of the molecules being transferred (e.g., molecules of the gas 20) .

It is understood that the diffusion rate depends on several factors including, for example, temperature, concentration difference, diffusion distance and host material. Temperature has significant effect on diffusion rates. Increasing the temperature increases the diffusion rate by adding energy to each particle. Higher concentration differences result in higher diffusion rates. Smaller distances result in faster diffusion rates and larger distances result in slower diffusion rates. Lighter atoms travel faster and are more mobile than larger atoms. Materials made of lighter atoms diffuse faster than heavier materials.

Techniques to promote mass transfer through the membrane are well known for each specific chemical system and including those that can be developed in the future and can be used in a gas-liquid exchange system such as described herein to facilitate mass transfer. Some examples of such techniques are discussed herein.

At the loosely defined interface between the membrane 5 and the liquid 25, exchanged components will be transferred to the bulk of the liquid 25 and carried away with the flow of the liquid 25. Creating gas-liquid phase contact in this manner provides various benefits. For example, independent flows of the gas 20 and the liquid 25 are possible in the gas-liquid exchange system 100 according to the present invention. It is also possible to use differential pressure during gas and liquid circulation, for instance, to promote mass transfer.

Specifically, the membrane 5 used in the gas-liquid exchange system 100 may contain a material that allows direct contact between the gas 20 and at least a portion of the liquid 25. The liquid 25 is not able to flow into the gas 20 at working conditions, thereby making it possible to independently control velocity and direction of the flow of the gas 20 and the flow of the liquid 25 to promote effective mass transfer.

Figure 3 schematically shows the organization of gas and liquid flows in a gas-liquid exchange system 100 according to an embodiment of the present invention. In Figure 3A, the respective flows of the gas 20 and the liquid 25 are organized in the similar direction. In Figure 3B, the respective flows of the gas 20 and the liquid 25 are organized in the counterflow direction. In Figure 3C, the gas 20 and liquid 25 each flow in various directions. It should be appreciated that the gas 20 and the liquid 25 may each or both flow in a direction perpendicular to the membrane surface, at an angle therewith, or in any direction that may promote mass transfer.

Furthermore, contact area between the gas 20 and the liquid 25 is defined by the structure and shape of the membrane 5. As such, it is possible to create very high contact surface area per unit of volume, thereby substantially increasing the contact time and kinetics between the gas 20 and the liquid 25. Accordingly, the gas-liquid exchange system 100 may be relatively small in size but still provide a surprisingly high contact surface area between the gas 20 and the liquid 25.

It is also possible to engineer membrane, such that it may improve the mass transfer rate of a selected component while reducing the mass transfer rate of another component. In this way, mass transfer process within a gas-liquid exchange system according to the present invention may have specific selectivity if needed.

Stimulation may be applied to the gas 20 and/or the liquid 25 for the purpose of promoting mass transfer therebetween. Exemplary stimulation includes varying pressure during the flow of the gas 20 and/or the liquid 25 through all 3-axis direction. Another example includes the use of ultrasonic waves in the liquid 25. Other examples of stimulation may include a variety of physical and chemical stimuli, where the physical stimuli include, for example, temperature, electric or magnetic field, light, pressure, mixing and/or sound, while the chemical stimuli include, for example, variations in pH, solvent composition, ionic strength, and /or molecular species.

Gas

The gas used in a gas-liquid exchange system according to the present invention maybe a product of combustion or any other industrial or commercial process. It may also come from the ventilation, internal combustion engines or just outdoor air. The gas may contain organic and inorganic compounds in a form of gas, particles or aerosols, and may have a broad temperature range (including but not limited to from about -50℃ to about 500℃; or from about 0℃ to about 250℃; or from about 0℃ to about 100℃) and a pressure range (including but not limited to about 0 to about 50 bar; or from about 0 to about 30 barg; or from 0 to 10 barg; or from 0 to 1 barg; or from 0 to 0.1 barg) .

Examples of emission sources include, but are not limited to, a combustion source, such as a power plant, a manufacturing facility, a waste incinerator, a fireplace, a oven, a boiler, a smelter, a furnace, a steam generator, a car, a bus, a truck and a ship, etc.; a chemical reaction source, a natural source, for example a gas well, an oil well, a fracking source, fuel combustion for electricity generation and for other purposes; other suitable industrial and civil processes, etc. The fuel used during combustion may vary. For example, the fuel may be natural gas, coal, waste coal, or a sulphur-containing fossil fuel, petrol, diesel, etc. Accordingly, the specific constituents of the gas derived from different emission sources may vary, in terms of compounds contained therein and/or the weight contents thereof.

In one embodiment, the gas can be in contact with a gas-liquid exchange system according to the present invention within a device for conveying exhaust gases. Examples of such a device include a flue, a duct, and a pipe.

The gas-liquid exchange system according to the present invention may remove SO _x, HCl, CO ₂, NH ₃, H ₂S, H ₂O, acid gas, formic acid, H ₂, O ₃, NO _x, Hg vapor, Cl ₂, I ₂, F ₂, CO, CH ₄, CH ₂O, benzene, toluene, Pb, Rn, HF, As, Se, Cd, ethylbenzene, xylene (o-, m-and p-) , pentane (i-, n-, 2M-, 3M-, MC-) , butane (i-, n-) , hexane (n-, MC-) , trans-2-pentene, trans-2-butene, 2-Methylpentane, 3-Methylpentane, Methylcyclopentane, Ethane, Propane, 2, 3-Dimethylbutane, 2, 3-dimethylpentane, Propylene, cyclohexane, dichloromethane, acrolein, ethene, MTBE, formaldehyde, acetone, isopropyl alcohol, carbon tetrachloride, carbon disulfide, vinyl chloride, trichloro ethylene, tetrachloroethylene, ethyl acetate, methanol, methylene chloride and a combination thereof. Such a system may be particularly useful in removing a volatile organic compound.

Liquid

The liquid used in a gas-liquid exchange system according to the present invention may be a liquid selected from those currently known or that will become known in the future to most effectively enable the required exchange to be carried out between the gas and the liquid. The liquid should have enough fluidity to allow the flow at operational temperature and pressure. The gas-liquid exchange system according to the present invention allows for the use of either polar or non-polar liquids. In addition, the gas-liquid exchange system of the present invention may work with a high ionic strength liquid (e.g. an ionic liquid or a mixture thereof where there can be negligible amount of solvent present) . Variation in the chemical composition of the liquid in some cases may provide the gas-liquid exchange process with selectivity.

In one embodiment, the gas may be a flue gas containing SOx, NOx, CO, CO2, mercury, etc., and may be initially treated in a gas-liquid exchange system according to the present invention, which pre-oxidizes nitric oxide to nitrogen dioxide, and mercury vapor to ionic mercury compounds, and additionally carbon monoxide and organic compounds to carbon dioxide and water vapor. Examples of the liquid suitable for such a pre-treatment process may include water, chlorine, chlorine dioxide, hydrogen peroxide and a choice of photolyzed chlorine, chlorine dioxide and hydrogen peroxide in sequence, an alkali metal chloride reagent solution.

The gas, having been through the pre-treatment, may then be passed through a second gas-liquid exchange system for any subsequent treatment. The gas-liquid exchange system used for subsequent treatment may be identical or similar to the gas-liquid exchange system used for the pre-treatment, but utilizes a liquid that is different from the liquid previously used for the pre-treatment. For instance, the liquid used for the subsequent treatment may be recycled reagent solution of alkali metal hydroxide, carbonate and bicarbonate to remove sulphur dioxide, nitrogen dioxide and carbon dioxide.

Following the subsequent treatment, the liquid used in the subsequent treatment may then be treated sequentially by means of oxidation, decarbonation and evaporation plus crystallization to facilitate removal of the respective alkali metal sulphate and nitrate salts as recovered solids. The carbon dioxide can be captured and recovered as a separate purified gas stream from the exhausts of the decarbonation units by the decomposition of alkali metal bicarbonates to carbonate salts in both the sulphur dioxide and nitrogen dioxide removal steps. The recovered alkali metal carbonate solutions generated from the evaporation and crystallization steps in both the sulphur dioxide and nitrogen dioxide removal steps are then diluted with water and recirculated and returned to their respective reactors after addition of makeup alkali metal hydroxide from the chemical generation-regeneration system. The recycled and regenerated liquid may be used for continuing pre-treatment and/or subsequent treatment of additional gas as described above.

In another embodiment, the gas contains SO ₂ and at least one other pollutant. The gas is subject to a gas-liquid exchange system according to the present invention and is in contact with the liquid, the liquid being an alkaline liquid and containing an oxidizing agent (e.g. NaClO ₂ solution) . Where the at least one other pollutant is gaseous NO, it is believed that NaClO ₂ reacts with the gaseous NO to form a more soluble nitrogen containing compound such as NO ₂ (or maybe even higher oxidation state forms such as N ₂O ₅) . Where the at least one other pollutant is elemental Hg vapor (Hg ⁰) , it is believed that NaClO ₂ reacts with the Hg vapor to form a more soluble ionic form of Hg (Hg ²⁺) . In these cases, the at least one other pollutant can be easily removed by being oxidized into a more water soluble form and then dissolved into the liquid. Accordingly, these pollutants can be easily removed through the use of the gas-liquid exchange system of the present invention, especially when NaClO ₂ is present.

Without intending to be bounded by theory, it is believed that the reaction between NO and NaClO ₂, in an alkaline solution, takes place as follows:

2NO+ClO ₂ ^-→2NO ₂+Cl ^-

4NO ₂ (g) +ClO ₂ ^-+4OH ^-→4NO ₃ ^-+Cl ^-+2H ₂O

Alternatively, the reaction under an acidic condition is believed to take place as follows:

4NO (g) +3ClO ₂ ^-+2H ₂O→4HNO ₃+3Cl ^-

The reaction between Hg ⁰ and NaClO ₂ in the NaClO ₂ solution is believed to take place as follows:

2Hg ⁰ (g) +ClO ₂ →2H ₂O→2Hg ²⁺+4OH ^-+Cl ^-

Some examples of the liquid suitable for use as the alkaline liquid include, but are not limited to, an aqueous solution of an alkaline or alkaline earth hydroxide, an alkaline earth oxide, an alkaline or alkaline earth carbonate, lime (CaO) , limestone, calcium carbonate (CaCO ₃) , and a mixture thereof. The alkaline substances used herein are commercially available and are cheap in costs. Further, they generally have good solubility in water and thus can be easily applied to a gas-liquid exchange system of the present invention. Alkaline liquids are able to readily react with acid gases to form corresponding salts. In many cases the liquid can be regenerated (e.g., carbon dioxide capture and extraction using potassium carbonate solutions, etc. ) . In other cases, various useful substances can be extracted. For instance, calcium sulfate generated in the gas-liquid exchange process may be extracted to manufacture plaster board) .

Some examples of the oxidizing agents suitable for being used in the liquid include, but are not limited to, a water soluble oxidizing salt, a water soluble halide containing a salt, NaClO ₂, NaClO ₃, H ₂O ₂, KMnO ₄, Ca (OCl) ₂, and a mixture thereof. In one embodiment, the oxidizing agent is NaClO ₂. The specific oxidizing agent to be used may be determined based on, for instance, oxidizing power, costs, solubility in a given solvent, stability, corrosivity etc.

The liquid may include an ionic liquid. The low vapor pressure of an ionic liquid minimizes loss of absorbing material during use and thus provides a simple mechanism for regeneration, such as distillation, evacuation, or extraction with a supercritical fluid. Such a supercritical fluid may be supercritical carbon dioxide.

In one example, the liquid may include an ionic liquid which selectively solubilizes impurities, leaving the desired gaseous components in the gas. It should be appreciated that in variations of the inventive concepts described herein, the liquid may include an ionic liquid that selectively solubilizes one or more desired gaseous components of the gas, leaving any impurity gaseous component behind in the gas. Distillation, evacuation, or extraction with a supercritical fluid, or the like, will regenerate the ionic liquid and simultaneously recover the one or more desired gaseous components in purified form.

Moreover, the liquid may include an ionic liquid which is tailored for specific needs, allowing a single absorption unit of a gas-liquid exchange system according to the present invention to be used for the removal of one or more specific desired gaseous components and/or impurities, depending on the relative solubilities and/or diffusabilities thereof in the ionic liquid.

It is appreciated that the anion component of an ionic liquid may impart acidic, basic, or neutral properties to the ionic liquid. As such, it is beneficial to consider such properties when choosing an ionic liquid for the liquid, such that the capacity or selectivity of the separation may be enhanced. For example, an ionic liquid exhibiting more basic character may be better suited for CO ₂ absorption rather than for ammonia absorption.

It is also appreciated that a dry ionic liquid may exhibit greater overall capacity for removing one or more gaseous components. This is because the presence of water in an ionic liquid may reduce its capacity for dissolving certain gaseous components. In addition, the presence of water may decrease the solubility of certain gas components in the ionic liquid, especially where those gaseous components are hydrophobic.

It is further appreciated that a dry ionic liquid may exhibit differential selectivity between various gaseous components when compared to an ionic liquid containing a measurable amount of dissolved water, such as an ionic liquid having been exposed to a humid atmosphere.

An ionic liquid may be dried by a conventional method, such as heat treatment, exposure to a reduced pressure environment, and a combination of heat and reduced pressure.

It is known that gas solubility in various liquids, including ionic liquids, is dependent upon temperature. Therefore it should be appreciated that different gaseous components may each have a different sensitivity to temperature changes, which in turn affects its solubility in an ionic liquid. Such differential temperature dependence may be advantageously used, for instance, by conducting gas-liquid exchange at different temperatures to optimize exchange and/or separation of various gaseous components.

Membrane

Mechanical Property and Density

It is appreciated that, with an increase in membrane force density of the membrane, it is possible to increase the ability of the membrane to retain liquid within its structure, thereby increasing allowable differential pressure between the gas and the liquid in a gas-liquid exchange system according to the present invention without the gas and the liquid intermixing with each other. In cases where the membrane force density of the membrane is very low, a combination of attractive forces may not be enough to maintain required differential pressure between the gas and the liquid.

It is also appreciated that a membrane type with very high membrane density has mechanical properties that may be compared to hard, plastic-like materials. This may affect in various ways how a gas-liquid exchange system operates. High membrane density in some cases can also increase resistance of the membrane to mass transfer, and is thus undesirable for a variety of gas-liquid exchange processes. On the other hand, in cases where membrane density is very low, the mechanical strength of the membrane may not be enough to maintain structural integrity.

In view of the above, the optimum membrane force density and membrane density can be determined for each system through taking into account both requirements for mechanical properties and mass transfer properties, and can be performed by a person skilled in the art based on actual needs. Exemplary membrane density can range from about 0.1%to 99.9%; or from about 1%to 99%; or from about 10%to about 75%; or from about 20%to about 50%.

Membrane force density can be quantified as the ability of the membrane to retain a portion of the liquid by measuring the highest absorbency under static load or pressure. It is important that material selection for the membrane for any individual application should produce highest durability and stability in the operational environment and during the storage.

Various structures and arrangements are also known in the art to produce a membrane with a wide range of mechanical and mass transfer properties without significant changes to membrane density. These techniques will be discussed in detail below and can be performed by a person skilled in the art. Thus, one of the advantageous features of the gas-liquid system according to the present invention is its ability to separate the liquid and the gas while maintaining high rates of mass transfer.

Membrane Deformation and Supporting Structures

It may be advantageous to subject the membrane to an external stimulation for the purpose of promoting mass transfer through the membrane. For instance, it is known that agitation generally increase mass transfer rates. In such cases, the fact that the membrane may be viscoelastic and is thus able to deform and then return to its previous state once the stress causing its deformation is removed may be advantageous in some cases.

However, in some other cases, it may be advantageous to provide the membrane with inner and/or outer supporting structures for the purpose of increasing strength and/or durability of the membrane.

Inner Supporting Structure (s)

Figure 4 schematically shows a cross-section of a gas-liquid exchange system 100 according to an embodiment of the present application, wherein the membrane 5 is formed over a porous, specifically microporous three-dimensional matrix 30.

Exemplary structures of the matrix 30 include felt, fabric, netting, mesh or the like that can be made of any suitable material to form the structure that is well known to those skilled in the art. Examples of materials suitable for use include a resign such as a plastic, a metal, glass, ceramic, a carbon fiber, a combination thereof and any suitable material that may be developed in the future.

The matrix 30 may increase strength and/or durability of the membrane 5. Surface of the matrix 30 may be modified prior to preparation of the membrane 5 to add specific functional groups (e.g. hydrophilic or hydrophobic groups or specific chemical interaction) that improve interaction between the liquid 25 and the membrane 5. For example, such groups may form covalent or ionic bond with the structure of the membrane 5 or interact therewith through any variety of intermolecular attractive forces. Such intermolecular attractive forces will be able to interact with the material of the membrane and the liquid. This in turn may increase allowable differential pressure between gas and liquid phases. It will also increase flexibility, which may lead to elimination of cracks during product assembly and service. Furthermore, it significantly increases the tensile strength of the overall system, thereby allowing for a thinner membrane and a higher mass transfer rate.

Specifically, the surface may be functionalized through various treatments to reach desired functionality. For instance, acid treatment may be used to introduce -OH and/or -OOH groups by, for example, soaking material into nitric acid (either concentrated and/or hot) . Another example of such treatments is oxidization. Various oxidizers may be used, including, for example, hydrogen peroxide, sodium hypochlorite, potassium permanganate acidified with concentrated HCl, etc. In a further example, the surface may be heat treated in the absence of air with ammonia gas to introduce -NH ₂ groups to increase hydrophilicity.

In a still further example, air or oxygen (O2) gas plasma may be used to produce a more hydrophilic surface via the addition of surface C-O and C=O groups. It will also increase surface wettability. Water vapor (H ₂O) may also be used to render the surface more hydrophilic, and may be especially advantageous for polymers. Alternatively, an argon plasma may be preferred for surface activation to minimize further oxidation of the surface (e.g. metals) . Other alternatives may include UV-ozone treatment of the surface.

In another example the surface may be coated with a material that provides one or more desired characteristics. For example, plasma coating technique may be used where different monomers are used to produce hydrophobic and hydrophilic surfaces. Suppliers include Henniker Plasma, 3 Berkeley Court, Manor Park, Runcorn, WA7 1TQ ( https: //plasmatreatment. co. uk/) .

Overall, depending on the material of the matrix 30, the type of liquid and gas used, surface treatment techniques will differ and are well known in the art.

There are many ways in which the membrane 5 can be in contact with the matrix 30. In one example shown in Figure 4A, the material of the membrane 5 may to some extent fill the pores present in the matrix 30. It is also possible that individual pieces of the material of the membrane 5 may not be interconnected and not cover the matrix 30 fully. Hence there may be parts of the matrix 30 in direct contact with the gas 20 and parts of the matrix 30 in direct contact with the liquid 25. In another example shown in Figure 4B, the membrane 5 may form a thin layer at the surface of the matrix 30. In yet another example shown in Figure 4C, the membrane 5 can fully fill the pores of the matrix 30 while individual pieces of the membrane 5 may not be interconnected and not cover the matrix 30 fully. In yet another example shown in Figure 4D, the membrane 5 can fully fill the pores and the surface of the matrix 30. Hence most area of the matrix 30 is not in direct contact with the gas 20 and with the liquid 25.

As mentioned earlier, the membrane 5 may fully or partially cover the matrix 30. It may be beneficial to fully cover the matrix 30 on the side of the membrane 5 in contact with the gas 20, because it may restrict the flow of the gas 20 over the surface of the membrane 5 and require the gas 20 to diffuse through the matrix 30. This consequently may add resistance to the overall mass transfer to and from gas 20. In cases where the membrane 5 is not fully covering the matrix 30 on the side of the liquid 25, the matrix 30 may reduce the flow of the liquid 25 near the contact area with the membrane 5. It is expected that there may be lower impact on the overall mass transfer in cases where a large portion of the matrix 30 remains uncovered by the membrane 5 on the side of the liquid 25. This is mainly because the typical flow of the liquid 25 is much smaller compared to that of the gas 20 in a typical gas-liquid exchange system 100.

It is appreciated that the portion of the matrix 30 not covered with the membrane 5 on one or both sides may offer several unique advantages during manufacturing and storage of components, assembly as well as operation of a gas-liquid exchange system 100 according to the present invention. Some examples include formation of channels for the circulation of the liquid 25 and the gas 20. Other examples include its role in connecting the membrane 5 with other components present in the gas-liquid exchange system 100 as well as formation of the seal at the edge of the membrane 5 that will prevent flows between the liquid 25 and the gas 20. Such advantages can be apparent to a person skilled in the relevant art.

Figure 5 schematically illustrates a cross-section of a gas-liquid exchange system 100 according to an embodiment of the present invention, showing various structures of the matrix 30. In Figure 5A, the matrix 30 is completely within the membrane 5. In Figure 5B, the matrix 30 extends into the liquid portion 15 to be in direct contact with the liquid 25. In Figure 5C, the matrix 30 extends into both the gas portion 10 and the liquid portion 15 to be in direct contact with the gas 20 and the liquid 25 respectively.

The use of an organic solvent may help to facilitate the distribution of the polymer of the membrane 5 throughout the matrix 30. This is because the use of an organic solvent may sometimes reduce difficulties in wetting and/or saturating the structure of the matrix 30.

A variety of organic solvents may be used. Exemplary organic solvents can include, without limitation, an alkane, a ketone, an ester, an ether, an alcohol, and the like, as well as a combinations of these solvents. For example, exemplary organic solvents can include heptane, ethyl acetate, butyl acetate, isoamyl acetate, dioctyl adipate, acetone, methyl ethyl ketone, methyl isobutyl ketone, isopropanol, diethyl ether, mineral spirits, petroleum distillate, and combinations thereof. The choice of an organic solvent or solvents for use can be affected by a variety of factors including, without limitation, solubility of the polymer of the membrane 5, boiling point of the solvent, molecular weight of the solvent, polarity of the solvent or solvent combination, and the like.

In one embodiment, the material of the membrane 5 is in the form of a stabilized water-miscible dispersion of polymeric solids. In this embodiment, the material can also contain a relatively small amount of acetone and ethylene glycol or other water-miscible solvents and surfactants that were used in the polymerization reaction when the material was made. Optionally, the dispersion of the material of the membrane 5 is stabilized with a stabilizing agent, such as, but not limited to, deionized and/or demineralized water. The stabilizing agent reduces the propensity of the material of the membrane 5 from settling out and agglomerating to a size which cannot enter a pore in the matrix 30. Although the composition of the material of the membrane 5 may include any suitable amount of stabilizing agent, in some embodiments the composition includes an amount of stabilizing agent in the range of about 5 wt %to 50 wt %. For example, in some embodiments the composition may include an amount of stabilizing agent in the range of about 15 wt %to about 25 wt %.

Outer Supporting structure (s)

Figure 6 schematically illustrates a cross-section of a gas-liquid exchange system 100 according to an embodiment of the present invention, wherein the membrane 5 is disposed on a layer of a substrate 35. The substrate 35 imparts strength and/or durability to the membrane 5. Examples of such structures include felt, fabric, netting, mesh or the like. It can be made of any suitable material including but not limited to a plastic, a metal, ceramic, a carbon fiber that are well known to a person skilled in the art as well as any other suitable materials that may be developed in the future.

In another embodiment, the membrane 5 is laminated to the substrate 35. The lamination of the membrane 5 may be by thermal means, adhesive means and the like.

The substrate 35 in contact with the membrane 5 should ideally be thin and should contribute minimum increase to the overall mass transfer resistance. Large size of open areas (e.g., pores) in the substrate 35 will increase the contact surface area between the gas 20 and/or the liquid 25 with the membrane 5 and should improve the overall gas-liquid exchange. However, larger size of the open areas will reduce the mechanical support given to the membrane 5 by the substrate 35. It can be advantageous to use a micro structured material having a large number of small pores such that the substrate 35 with the small pores can maintain high proportion of open surface area while at the same time providing the required support to the membrane 5. Exemplary average pore size can range from of about 0.01 to about 2000 microns; or about 1 to about 500 microns; or about 10 to about 100 microns. Exemplary average proportion of open surface area of a particular substrate can range from 1%to 100%; or 50%to 99%; or 75%to 90%.

Figure 7 schematically illustrates how layers of the substrate 35 may be used in a gas-liquid exchange system 100 according to an embodiment of the present invention. As shown by Figure 7A, layers of the substrate 35 are used to create flow area for the circulation of gas 20 and/or liquid 25. As shown by Figure 7B, the substrate 35 is designed to support more than one membranes 5.

In another embodiment, no substrate 35 is required on one or both sides of the membrane 5. The shape and position of the membrane 5 can be maintained through control of the pressure of liquid 25 and/or gas 20 as well as control of the amount of liquid 25 present.

Other designs where the flow of gas 20 and liquid 25 can be made possible on either side of the membrane 5 can be used by those skilled in the art.

Dimension and Shape of Membrane

The dimensions (e.g. length width or diameter) of the membrane may vary and will depend on the use of the gas-liquid exchange system according to the present invention. Specifically, dimensions of the membrane can be determined based on, for instance, flow rates, amount of mass transfer exchange required or lifetime of the gas-liquid exchange system according to the present invention.

A gas-liquid exchange system of the present invention may include a single layer or multiple layers of the membrane. In one embodiment, the membrane can be configured as a hollow tube or tubes. In such a configuration, liquid can flow on the outside of the tube and the gas can flow inside. Conversely, the membrane configured as a hollow tube or hollow tubes can be effective when the liquid flows within the tube (s) and the gas flows outside.

The membrane can be flat or can have rough or very rough surface including fibers, balls, ridges and the like. It should be appreciated that an increase in contact surface area due to various structures will increase mass transfer properties and the overall performance of the gas-liquid exchange system of the present invention.

The thickness of the membrane may be determined based on the specific requirements of a gas-liquid exchange system of the present invention. Factors that may be taken into consideration include, for instance, mechanical properties, system assembly, mass transfer rate, absorption rate etc.

Thinner membranes will generally have smaller resistance to mass transfer rate compared to the thicker membranes. In some embodiments, however, it may be possible to produce thin films with good mechanical properties but poor mass transfer rates (e.g. very dense, highly interlinked polymer membranes) . In other cases, thicker membranes may have poor mechanical properties and high rates of mass transfer (e.g. low interconnection and low density of polymer chains, various additives present that promote fast rate of mass transfer for example through channel diffusion) .

Figure 8 schematically illustrates possible configurations of the membrane 5 according to an embodiment of the present invention. In Figure 8, the membrane 5 is configured to have a rough surface. Figure 8A illustrates a relatively thin membrane 5, whereas Figure 8B illustrates a relatively thick membrane 5.

In some embodiments, for example, thickness of the membrane for the gas-liquid exchange system of the present invention can be in a range of about 0.5 μm to about 2000 μm; or from about 4 μm to about 500 μm; or from about 10 μm to about 150 μm; or from about 25 μm to about 100 μm. However, it is appreciated that either greater or smaller thicknesses may be used, depending on actual needs and/or the specific material used for the membrane.

In another embodiment, the membrane has a first thickness and a second thickness, the first thickness being different from the second thickness. In further embodiment, the membrane has the same thickness across its entire length.

Material and Structure of Membrane

Material and structure of the membrane should provide sufficient stability towards chemical and mechanical degradation under operating conditions such as temperature, mechanical agitation, various chemicals present in the gas and the liquid, rate of temperature and pressure change etc.

Structure Type

In one embodiment, the membrane can include a linear polymer that is simply a chain in which all of the carbon-carbon bonds exist in a single straight line. An example of a linear polymer is polytetrafluoroethene, which is made from tetrafluoroethylene. In another embodiment the membrane can include a branched polymer where groups of units branch off from the long polymer chain. These branches are known as side chains and can also be very long groups of repeating structures. Branching may result from the formation of carbon-carbon or various other types of covalent bonds. Branching by ester and amide bonds is typically achieved by a condensation reaction, producing one molecule of water (or HCl) for each bond formed. Example of branched polymers include low density polyethylene.

The membrane can contain several interpenetrating networks, each of which may be a combination of any of the above-mentioned types of polymers. It may be beneficial to use interpenetrating networks where individual networks provide added functionality to the whole system. For example, one of the networks can provide the membrane with the ability to retain liquid while another imparts the required mechanical strength and durability or provides important characteristic for integration with other components (e.g. to achieve sealing between the gas and the liquid at the edge of the membrane) as well as overall device assembly. In another example, one of the networks can provide the membrane with the ability to retain liquid while the other is responsive to an external stimulus including temperature, electric or magnetic field, light, pressure, and sound, pH, solvent composition, ionic strength, and molecular species.

Monomer Type

The membrane can be derived from polymerization of a variety of monomers and/or oligomers known to produce the desired backbone. A monomer or oligomer can optionally be copolymerized with another monomers or oligomer, examples including formation of copolymer, alternating, random or block-wise polymer. Examples of monomers or oligomers may include a (C1-32) hydrocarbon moiety, in particular a (C1-32) alkyl moiety.

In one embodiment, an alkyl moiety is present, in particular -CH ₃, -CH ₂-CH ₃, -CH ₂-CH ₂-CH ₃. In another embodiment, a (C1-12) alkylene moiety is present, in particular -CH ₂-, -CH ₂-CH ₂-, -CH ₂-CH ₂-CH ₂-. Exemplary monomer or oligomer units can include, for example, (C1-16) alkylacrylate, (C1-16) alkyl methacrylate, (C1-12) alkylmaleic acid ester, (C1-12) alkyl (C6-12) aryl urethane oligomer, (C1-12) alkyl allyl urethane oligomer, (C1-12) alkyl urethaneacrylate oligomer. A monomer or oligomer may optionally be polymerized with an additional fluorinated monomer or oligomer including for example fluoro (C1-16) alkylacrylate and fluoro (C1-16) alkyl methacrylate.

Specific exemplary classes of oleophobic polymers include, without limitation, an apolar perfluoroalkylpolyether having -CF ₃, -CF ₂CF ₃, and -CF ₂CF ₂CF ₃ moiety (PFPE) , a mixture of apolar PFPE with polar monofunctional PFPE, polar water-insoluble PFPE with phosphate, silane, or amide end groups, a mixture of apolar PFPE with fluorinated or perfluorinated (C1-12) alkyl methacrylate polymer or fluorinated or perfluorinated (C1-12) alkyl acrylate polymer, and a copolymer comprising a perfluoro (C1-3) alkylether unit, fluorinated or perfluorinated (C1-12) alkyl methacrylate unit, or fluorinated or perfluorinated (C1-12) alkyl acrylate unit.

Other examples of monomers for creating a water-insoluble polymer include, without limitation, a (meth) acrylic ester, vinyl acetate, a maleic acid ester, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, butyl (meth) acrylate, vinyl acetate, alone or a copolymer of hydrophobic monomers such as dioctyl maleate, ethylene, propylene, butylene, methyl (meth) acrylate, ethyl (meth) acrylate.

One specific form that the oleophobic polymers are commercially available is emulsions. Exemplary emulsions can include, without limitation, those based on a copolymer of siloxane and (C1-12) alkyl-substituted acrylate or methacrylate, one type of unit containing at least alkyl vinyl ether, emulsions based on (C1-12) alkyl-substituted polyacrylate and methacrylate, and the like. These polymers and their preparation are well known to a person skilled in the art.

Non limiting examples of monomers may further include acrylamide, N-methylacrylamide, N-ethylacrylamide, cyclopropylacrylamide, N-isopropylacrylamide, methacrylamide, N-methylmethacrylamide, cyclopropylmethacrylamide, N-isopropylmethacrylamide, dimethylacrylamide, N, N-dimethylaminopropylacrylamide, N-methyl-N-ethylacrylamide, N-methyl-N-isopropylacrylamide, N-methyl-N-ethylacrylamide, N-methyl-N-isopropylacrylamide, N-methyl-N-n-propylacrylamide, N, N-diethylacrylamide, N-acryloylpyrrolidine, N-acryloylpiperidine, N-acryloylmethylhomopiperidine, N-acryloylmethylpiperidine, and N-acryloylmethylpiperidine.

More specific examples of the polymer encompass: poly (N-alkyl (meth) acrylamide) such as poly (N-isopropyl (meth) acrylamide) , poly (N-n-propyl (meth) acrylamide) , poly (N-methyl (meth) acrylamide) , poly (N-ethyl (meth) acrylamide) , poly (N-n-butyl (meth) acrylamide) , poly (N-isobutyl (meth) acrylamide) , and poly (N-t-butyl (meth) acrylamide) ; poly (N-vinylalkylamide) such as poly (N-vinylisopropylamide) , poly (N-vinyl n-propylamide) , poly (N-vinyl n-butylamide) , poly (N-vinylisobutylamide) , and poly (N-vinyl-t-butylamide) ; poly (N-vinylpyrrolidone) ; poly (2-alkyl-2-oxazoline) such as poly (2-ethyl-2-oxazoline) , poly (2-isopropyl-2-oxazoline) , and poly (2-n-propyl-2-oxazoline) ; polyvinyl alkyl ethers such as polyvinyl methyl ether and polyvinyl ethyl ether; a copolymer of polyethylene oxide and polypropylene oxide; poly (oxyethylene vinyl ether) ; cellulose derivatives such as methyl cellulose, ethyl cellulose, hydroxypropyl cellulose, and hydroxypropyl methyl cellulose; and copolymers of the above polymers. Other examples include N-alkyl (meth) acrylamides such as N-isopropyl (meth) acrylamide, N-n-propyl (meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-n-butyl (meth) acrylamide, N-isobutyl (meth) acrylamide, and N-t-butyl (meth) acrylamide; N-vinylalkylamides such as N-vinylisopropylamide, N-vinyl n-propylamide, N-vinyl n-butylamide, N-vinylisobutylamide, and N-vinyl-t-butylamide; vinyl alkyl ethers such as vinyl methyl ether and vinyl ethyl ether; ethylene oxide and propylene oxide; and 2-alkyl-2-oxazolines such as 2-ethyl-2-oxazoline, 2-isopropyl-2-oxazoline, and 2-n-propyl-2-oxazoline.

Other materials and preparations techniques are well known in the art (Structure and Properties of Hydrophobic Aggregation Hydrogel with Chemical Sensitive Switch, Duan et al., International Journal of Polymer Science, Volume 2017, Article ID 9123248, the content of which is hereby incorporated by reference in its entirety) .

Crosslink Type

The cross-linked polymer forms long chains, either branched or linear, that can form covalent or ionic bonds between the polymer molecules. Cross-linked polymers form bonds that are much stronger than the intermolecular forces that attract other polymer chains, resulting in a stronger and more stable material. An example of such crossed-linked polymers is vulcanized natural rubber, which means it is heated so the sulphur molecules in the rubber polymer chains form covalent bonds with one another. Cross-linked polymers can be produced by other techniques, such as free-radical polymerization, condensation reactions, small molecules cross linking and radiation (Role of cross-linking process on the performance of PMMA, Albeladi, et al., Int. J. Biosen. Bioelectron. vol. 3, Issue 3, pp. 279-84 (2017) , the content of which is hereby incorporated by reference in its entirety) .

Free radical polymerization requires the use of an initiator and heat. Chemically cross-linked polymers can be produced using techniques such as suspension, emulsion, and dispersion polymerization techniques.

Cross-linking through condensation reactions takes place in the presence of heat, catalyst, or both. Polymer with diamine compounds can be produced by condensation reactions among the carbonyl group (>C=O) with amine group (-NH) . These reactions may be used to improve thermal steadiness and texture behavior by means of normal chemical action by the use of aliphatic and aromatic diamines in several ratios as cross-linking agents.

Some small-molecules considered as a cross-linker and used potentially to obtain cross-linked polymer such as formaldehyde, glutaraldehyde, potassium dichromate, osmium tetroxide, and potassium permanganate, other than the multifunctional (bi, tri, or tetra) cross-linking agents.

During crosslinking via free radical polymerization, through condensation reactions and with the use of small molecules, degree of cross-linking is controlled by an amount of cross-linker, reaction time, temperature, stirring speed, and an initiator/catalyst (type and concentration) .

Cross-linking can occur using radiation treatment such as the gamma exposure, proton, electron, UV, implantation and ion irradiation. Examples include rubber tires, wires, cross-linked cables, development of cross-linked silicon carbide fibers and polymer recycling. High energy electromagnetic irradiation can crosslink water-soluble monomer or polymer chain ends without the addition of a crosslinker. During irradiation, using a gamma or electron beam, solutions of monomers are polymerized to form a membrane. This process has an advantage over other crosslinking methods, since it can be performed at room temperature and in physiological pH without using toxic and hard to remove crosslinking agents.

During crosslinking via radiation treatment, the degree of cross-linking is controlled by high-energy ionizing radiation, gamma, x-ray or other and their radiation dose.

Cross-linking processes have been widely utilized in order to overcome the significant week points in polymeric materials, such as rigidity, mechanical strength, strain modulus, stiffness, thermal stability as well as morphological behaviors. A cross-linked product is significantly affected by the type of cross-linker and its concentration. Properties like thermal degradation, glass transition, particle size, pore size, pore volume, surface area, and swelling are totally changed after cross-linking occurred. Important cross-linker types are hydrophilic, hydrophobic, rigid, or flexible.

Monomers that can be used as cross-linkers or cross-linking agents are well known in the art with some examples including N, N′-Bisacrylamide, N, N′-BIS (ACRYLOYL) -CYSTAMINE, ethylenediamine, 1, 3-propanediamine, 1, 3-propanedithiol, dithiothreitol, dithioerythritol, 1, 5-pentanediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, propylenediamine, di (aminomethyl) ether, 1, 8-diamino-4- (aminomethyl) octane, xylylenediamine, hydroquinone, bisphenol A, bisphenol sulfone, 1, 4-butanedisulfinic acid, benzenedisulfinic acid, thioethanolamine, p-aminothiophenol, and butylenediamine, ethyleneglycol dimethacrylate, trimethylolpropane triacrylate, hexamethyleneglycol dimethacrylate, glycerol α, α’-diallylether, n-methylol acrylamide, vinylbenzene chloride, allyl chloride, gloxal, polyvinyl alcohol, polyethyleneimine, 1-vinylimidazole, hexadiene, tetraethylene glycol dimethacrylate, divinyl benzene, 1, 6-diaminohexane, p-phenylenediamine, ethylene glycoldi (meth) acrylate, propylene glycoldi (meth) acrylate, N, N′-methylenebis (meth) acrylamide, tolylene diisocyanate, divinylbenzene, and polyethylene glycoldi (meth) acrylate; glutaraldehyde; polyvalent alcohol; polyvalent amine; polyvalent carboxylic acid; and a metal ion such as calcium ion and zinc ion; and combinations thereof. These crosslinking agents can be used alone, or two or more kinds of these crosslinking agents can be used in combination.

The materials and preparations techniques of cross-linked polymers are well known in the art (Cross-linking in Hydrogels –A Review, Maitra, et al., American Journal of Polymer Science vol. 4, issue 2, pp. 25-31 (2014) , the content of which is hereby incorporated by reference in its entirety) .

Membrane Filling

Incorporation of a filler into the membrane 5 may be beneficial to enhance the performance of the membrane in terms of its mechanical, chemical, physical, and/or biological properties. Examples of fillers include reinforcing fiber (e.g. baron, carbon, fibrous minerals, glass, Kevlar, etc. ) that generally can increase tensile strength. Other examples include conductive fillers (e.g. aluminum powders, carbon fiber, graphite etc. ) that improve electrical and thermal conductivity and coupling agents (e.g. silanes and titanites) that improve interface bonding between polymer matrix and the fibers. In other examples, particulate substances such as nanoclay (bentonite, halloysite etc. ) and nanoparticles (silicon dioxide, titanium dioxide, etc. ) may enhance the mechanical properties of the membrane and are known in the art to promote mass transfer. Another example includes polymer chains (e.g. Poly (vinyl alcohol) , Carboxymethyl cellulose) that can be used as a structure reinforcing agents.

Self-Healing Properties

In one embodiment, introducing dynamic bonds such as hydrogen bonds, metal-ligand coordination, ionic bonds and associations may be used to realize a self-healing property of the membrane. Without the restriction of covalent cross-linking, the chains in an ionic supramolecular network have good flexibility and mobility. The ability of the ionic cross-links to easily reconstruct and rearrange facilitates the self-healing behavior of the membrane, thereby enabling a fully cut sample to re-join and retain its original properties after a suitable self-healing process at ambient temperature. Such materials and preparations techniques are well known in the art (Dynamic ionic crosslinks enable high strength and ultrastretchability in a single elastomer, Miwa et al., Communications Chemistry vol. 1, Article number 5, pp. 1-8 (2018) , the contents of which are hereby incorporated by reference in its entirety) .

In one embodiment, the membrane may balance mechanical properties such as tensile strength, elongation at break and the ability to self-repair. The toughness and stretch ability arises from the reversible cross-linking interactions between the polymer chains that help dissipate energy through stress (deformation) triggered dynamic processes.

Membrane Preparation

The preparation process of the membrane can include any suitable method for forming three-dimensional networks of polymers or fibers, and is well known to those skilled in the art. Exemplary techniques may include applying the composition of the membrane on a substrate, mould or matrix in a liquid form, e.g., a melt, or solution, or latex dispersion of the composition material. Exemplary methods for applying the composition material in the liquid form may include, without limitation, dipping, painting, spraying, roller-coating, brushing, and the like, over the surface of the substrate, mould or matrix. Regardless of the technique, the application can be carried out until internal surfaces of the substrate, mould or matrix are coated with composition of the membrane. Formation of the membrane can be achieved by varying the concentration, solids content of the solution or dispersion, and/or by varying the application temperature, or pressure.

A membrane that includes polymers can be prepared through any method known in the art. Exemplary techniques include radical, addition, condensation as well as Gamma and Electron Beam Polymerization.

Examples of addition (also known as Chain-growth) polymerization include free-radical polymerization, controlled-radical polymerization as well as anionic and cationic polymerization, all of which are well-known in the art. Free radical polymerization consists of initiation, propagation, and termination. After initiation, a free radical active site is generated which adds monomers in a chain link-like fashion. Controlled living radical polymerizations offer the benefits of longer growing chain life with examples including atomic transfer radical polymerization (ATRP) and Reversible addition fragmentation transfer (RAFT) polymerization.

Similar to addition polymerization, during condensation polymerization functional groups react in a step-wise manner to form a covalently linked gel network with examples including polyurethanes, polyesters, or nylon polymers.

Gamma and electron beam polymerizations parallel the initiation, propagation, and termination model held in free radical polymerization. In this process, hydroxyl radicals are formed and initiate free radical polymerization among the vinyl monomers which propagate in a rapid chain addition fashion.

Exemplary initiators/catalysts for radical polymerization are those that are water soluble and those that can be substantially homogeneously dispersed in water. Non-limiting examples include a water soluble peroxide, such as potassium peroxidisulfate and ammonium peroxidisulfate; water soluble azo compounds non-limiting examples of which include azo-bis-isobutyrate imidazoline hydrochloride, 2, 2′-azobis (2-methylpropionamidine) -dihydrochloride, and 4, 4′-Azobis (4-cyanovaleric acid) , as well as various other water soluble radical initiators having poly (ethylene oxide) chains.

As an example of the photopolymerization initiators are alpha-hydroxy ketones, alpha-amino ketone, benzyl methyl ketal, bis acyl phosphine oxide, metallocene, and the like. More specifically, 2-hydroxy-2-methyl-1-phenyl -propane-1-one, 1-hydroxy -cyclohexyl -phenyl -ketone, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl -propan-1-one, 2-methyl-1 - [ (methylthio) phenyl] -2-morpholinopropan-1-one, 2-benzyl -2-dimethylamino-1- (4-morpholinophenyl) , 2-a hydroxy-1- {4-[4- (2-hydroxy-2-methyl -propionyl) -benzyl] phenyl} -2-methyl -propan-1-one. These initiators may be used independently or in combinations.

Non-limiting examples of catalysts suitable for use herein include N, N′, N′-tetramethylethylenediamine and β-Dimethylaminopropionitrile.

The polymerization temperature is optionally set to a range of 0℃ to 100℃ in conformity with the selected initiator and catalyst, and which is within the skills of those skilled in the art. The polymerization time, also, will vary with the type of catalyst and initiator and polymerization conditions such as the amount of polymerizing solution (concentration) , and the polymerization time periods are within a few seconds to hours. An exemplary method of carrying out the polymerization is to make an aqueous solution of the monomer, add an initiator to the solution, and then add the catalyst.

In another embodiment the membrane can be produced through the use or functionalization of existing polymers (natural or artificial) .

Exemplary Applications

The gas-liquid exchange system described herein can be used in any gas-to-liquid or liquid-to-gas exchange systems. The system may be used for the following purposes:

● SO ₂, HCL, CO ₂, NH ₃, H ₂S, VOC flue gas and off gas treatment

● H ₂O, H ₂S, acid gas removal from Natural Gas and fuel mixtures

● O ₃, SO ₂, NOx and smell removal from indoor air

● CO ₂ recovery

● Mercury removal

● Desulfurization of biogas

● Palm oil deacidification

● Iodide oxidation

● Olefin/paraffin separation

● Oxygenation/deoxygenation

● Gas humidity control in various applications (humidification/dehumidification)

● Volatilization of products (natural extracts, aroma compounds, alcohol etc. )

The use of the present invention instead of the current technologies can reduce capital and operational costs, increase efficiency of the system, reduce space and weight requirements, reduce balance of plant equipment requirement (e.g. outlet gas purification systems, differential pressure control equipment, liquid and gas flow control devices etc. ) .

As previously discussed, through the design of the membrane, the present invention can provide a gas-liquid exchange system of a small size with a high contact surface area. The reduction in size may lead to considerable cost savings in industrial settings. It also makes it possible to apply a gas-liquid exchange system according to the present invention to civil settings, where size and aesthetics are usually the major concern.

Carbon Dioxide Recovery

Figure 9 schematically illustrates a gas-liquid exchange system 100 according to an embodiment of the present invention, wherein the system 100 is used for CO ₂ removal. While the discussion below focuses on the use of the system 100 in a downstream application for an exhaust system, it is to be understood that the system 100 described herein can be employed in any system employing the gas-liquid contacting technology described in the present application. Further, the system 100 can be particularly advantageous in processes where weight, size, cost, energy consumption, and/or environmental aspects are key concerns.

In the particular embodiment illustrated by Figure 9, the system 100 functions as a CO ₂ absorption unit. In the system 100, gas 20, being exhaust gas in this embodiment, is fed into the system 100 through a gas inlet end 40. The gas 20 may be cooled first prior to being fed into the system 100, in order to reduce the volume of the gas, which in turn reduces the size and weight of the system 100. The gas 20 exits the system 100 via the gas outlet end 45 in a purified form (i.e., the CO ₂-free) , and may be directly vented to atmosphere or further treated or recycled for energy recovery.

The liquid 25 is fed into the system 100 through the liquid inlet 50, and exits the system 100 via the liquid outlet 55 in a CO ₂-rich form. The CO ₂-rich liquid 25, having exited the system 100, may be further treated, for example through desorption, compression, sequestration, and the like.

The gas-liquid exchange system 100 may include a single module 60 or multiple modules 60. In the particular embodiment illustrated by Figure 9, there are a plurality of the modules 60 disposed in the housing 65 of the system 100. The number and size of the modules 60 will depend on the volume of the gas 20, the concentration of CO ₂ in the gas 20, and the like. The modules 60 in the system 100 may have a variety of shapes including, without limitation, sheets, hollow fibers, and the like. As shown in Figure 9, each of the modules 60 contains sheets of the membranes 5, which contain the liquid 25 within each of the modules 60 and defines the flow path for the gas 20.

In the particular embodiment illustrated by Figure 9, the liquid 25 contains an amine-based sorbent which is capable of absorbing CO ₂ from the gas 20. The amine-based sorbent is a liquid sorbent, and exemplary characteristics thereof include, for instance, low volatility, nontoxicity, low viscosity, the ability to absorb CO ₂ from low partial pressures (e.g., less than about 1 kilopascal (kPa) ) , and the like. Exemplary amine-based sorbents may include an amine, such as 2-amino-2-methyl-1, 3-propanediol, 2-hydroxyethyl piperazine, methyldiethanolamine, monoethanolamine, tetraethylenepentamine, triethanolamine, polyethylene imine, and other like amine based sorbents. In an exemplary embodiment, the amine-base sorbent can be a monoethanolamine (MEA) .

In order to further enhance the CO ₂ sorption rates of the amine-based sorbent, reduce its viscosity, and facilitate transport of the absorbed CO ₂, a solvent can be added to the liquid 25. Exemplary solvents can possess the same low volatility, low viscosity, and nontoxic properties of the amine based sorbent. Exemplary solvents can include, without limitation, an alcohol, a cyclic ketone, an ester, an ether, and a mixture thereof, including dimethyl ether of polyethylene glycol, glycerol, methoxy triethylene, glycol diacetate, polyethylene glycol, propylene carbonate, 1, 2-propylene glycol, and the like. The solvent used with a particular amine-base sorbent for a given application can readily be determined by a person skilled in the art. Exemplary factors for the selection of such a solvent and the amine-based sorbent may include chemical compatibility, solubility of the amine based sorbent in the solvent, absorption/desorption kinetics, nontoxicity, low viscosity, low volatility, and the like.

The chemical reaction for amine absorption is:

2 (R-NH ₂) +H ₂O+CO ₂→ (R-NH ₃) ₂CO ₃, wherein R ═ C ₂H ₄OH.

The reaction is reversible and the equilibrium can be altered by altering the temperature. The CO ₂ in the gas 20 is absorbed by the liquid 25 in a temperature range of about 20℃ to about 70℃. Each of the modules 60 provides an interface for contact between the gas 20 and the liquid 25. The separation is caused by the presence of the amine-based sorbent in the liquid 25 on one side of the membrane 5, which selectively removes CO ₂ from the gas 20 on the other side of the membrane 5. The membrane 5 is intended to serve as a contacting area which prevents mixing of the gas 20 and the liquid 25. The selectivity in the gas-liquid exchange process is derived from the amine-based sorbent within the liquid 25. Accordingly, a highly selective gas-liquid exchange can be achieved through an appropriate choice of the amine-based sorbent for the liquid 25.

The system 100 has several advantages over conventional contacting devices such as packed columns. The size of the system 100 through the use of hollow-fiber or sheet-shaped membranes 5 is typically smaller than packed column filter media, because the membranes 5 have a much greater surface area per volume (cm ²/cm ³) . The height of the modules 60 in the system 100 will likewise be significantly reduced compared to current columns for the same reason. As such, the system 100 may be used, for instance, in a gas turbine. In some cases, the reduction can be as great as about 80%of the packed column height.

Moreover, the system 100 does not have the same entrainment, flooding, channeling or foaming issues typically found in current packed bed columns. Still further, the system 100 can be employed in a wider variety of liquid compositions. All of these benefits lead to size, weight, cost, and environmental savings over current gas-liquid separation systems.

Carbon dioxide which is captured from the gas 20 and then recovered from the liquid 25 may be sold as an end product, to be used for the enhanced tertiary recovery of oil, or for enhanced vegetable crop growth, or to produce algae for BioDiesel fuel, or to be sequestered. Carbon dioxide may also be utilized as a feedstock to produce commercial end-products such as methanol, ethanol (which may be considered as a feedstock for making BioFuels and transportation fuels) and ethylene (with ethylene, or more specifically ethylene dichloride, being an intermediate for polyvinyl chloride plastics production) .

Gas Humidity Control

It is appreciated that the present invention may be particularly useful for situations where humidity control is required, particularly where chemical and/or electrochemical reactions take place. Such situations may require humidity control to supply water to a reaction or to extract water from a reaction, and are well known in the art (see for example WO 2016/148637 A1 to Izgorodin, et al., assigned to H2SG Energy PTE. LTD. of Singapore, Singapore, published on September 22, 2016, the disclosure of which is hereby incorporated by reference in its entirety) .

Figure 10 schematically illustrates a gas-liquid exchange system 100 according an embodiment of the present invention in an electrolysis system 70 for the purpose of controlling humidity. In this case, the system 100 functions as a humidity control unit that can supply water to the electrolysis system 70. In this example, during operation of the electrolysis system 70, hydrogen gas will be produced and collected in a compartment 75. The portion of the hydrogen gas in the compartment 75 can be directed via an outlet 80 into the gas-liquid exchange system 100 and entrains water vapor therein. Resulting water vapor is fed into the compartment 75 of each electrolysis system 70 via an inlet 85. A pump 90 may be used to create the required gas flow to be fed into the system 100. Water supply 95 can be used to replenish the water lost in the gas-liquid exchange system 100.

With the gas-liquid exchange system 100, it is possible on the one hand to maintain continuous operation for humidification of feed air and on the other hand to maintain continuous operation for dehumidification of feed air, and to switch between the two operating modes.

The techniques to regulate the amount of water supplied or withdrawn can be controlled, for instance, through controlling the gas flow speed, temperature and/or chemical composition of the liquid in the gas-liquid exchange system 100. It is appreciated that techniques in this aspect are well known in the art.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the embodiments of the invention belong. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

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

All references specifically cited herein are hereby incorporated by reference in their entireties. However, the citation or incorporation of such a reference is not necessarily an admission as to its appropriateness, citability, and/or availability as prior art to/against the present invention.

Non-limiting embodiments of the present invention include:

1. A gas-liquid exchange system for containing a gas and a liquid, comprising:

A) a chamber comprising;

i) a first inlet for introducing a stream of a gas into the chamber;

ii) a first outlet in fluid communication with the first inlet, through which the gas exits the chamber;

iii) a second inlet for directing a stream of a liquid into the chamber;

(iv) a second outlet in fluid communication with the second inlet, through which the liquid exits the chamber; and

v) a membrane within the chamber for gas-liquid contact, wherein the membrane divides the chamber into at least a gas portion and a liquid portion, the gas portion receiving the gas from the first inlet and discharging the gas via the first outlet, and the liquid portion receiving the liquid from the second inlet and discharging the liquid via the second outlet,

characterized in that the membrane contains the liquid within the liquid portion and that the membrane at least partly defines a flow path for the gas within the chamber, wherein the gas and the liquid are in contact at the membrane and at least a portion of an ingredient in one of the gas and the liquid enters into the other of gas and the liquid upon the contact.

2. The gas-liquid exchange system according to embodiment 1, wherein the membrane comprises a three-dimensional network comprising a material selected from the group consisting of a polymer, a fiber and a combination thereof, wherein the membrane contains the liquid within the liquid portion through an intermolecular attractive force.

3. The gas-liquid exchange system according to any one of the preceding embodiments, wherein the gas comes from a source selected from the group consisting of combustion, ventilation, manufacturing, air and a combination thereof.

4. The gas-liquid exchange system according to any one of the preceding embodiments, wherein the gas comprises emission from a source selected from the group consisting of a power plant, a manufacturing facility, a waste incinerator, a fireplace, an oven, a boiler, a smelter, a furnace, a steam generator, a vehicle and a combination thereof.

5. The gas-liquid exchange system according to any one of the preceding embodiments, wherein the ingredient is selected from the group consisting of an organic compound, a metal, an inorganic compound and a combination thereof.

6. The gas-liquid exchange system according to any one of the preceding embodiments, wherein the ingredient is selected from the group consisting of SO _x, HCl, CO ₂, NH ₃, H ₂S, H ₂O, acid gas, formic acid, H ₂, O ₃, NO _x, Hg vapor, Cl ₂, I ₂, F ₂, CO, CH ₄, CH ₂O, benzene, toluene, Pb, Rn, HF, As, Se, Cd, ethylbenzene, xylene (o-, m-and p-) , pentane (i-, n-, 2M-, 3M-, MC-) , butane (i-, n-) , hexane (n-, MC-) , trans-2-pentene, trans-2-butene, 2-Methylpentane, 3-Methylpentane, Methylcyclopentane, Ethane, Propane, 2, 3-Dimethylbutane, 2, 3-dimethylpentane, Propylene, cyclohexane, dichloromethane, acrolein, ethene, MTBE, formaldehyde, acetone, isopropyl alcohol, carbon tetrachloride, carbon disulfide, vinyl chloride, trichloro ethylene, tetrachloroethylene, ethyl acetate, methanol, methylene chloride and a combination thereof.

7. The gas-liquid exchange system according to any one of the preceding embodiments, wherein the liquid is selected from the group consisting of a polar solvent, a non-polar solvent, an ionic liquid and a combination thereof.

8. The gas-liquid exchange system according to any one of the preceding embodiments, wherein the liquid is acidic, alkaline, or neutral, optionally comprising an oxidizing agent.

9. The gas-liquid exchange system according to any one of the preceding embodiments, wherein the liquid is selected from the group consisting of water, chlorine, chlorine dioxide, hydrogen peroxide and a choice of photolyzed chlorine, chlorine dioxide and hydrogen peroxide, alkali metal chloride, alkali metal hydroxide, carbonate and bicarbonate, an aqueous solution of an alkaline or alkaline earth hydroxide, an alkaline earth oxide, an alkaline or alkaline earth carbonate, lime (CaO) , limestone, calcium carbonate (CaCO ₃) , an aqueous solution selected from the group consisting of water soluble oxidizing salts, water soluble halide containing salts, NaClO ₂, NaClO ₃, H ₂O ₂, KMnO ₄, Ca (OCl) ₂, and a combination thereof.

10. The gas-liquid exchange system according to any one of the preceding embodiments, wherein at least a portion of the ingredient in one of the gas and the liquid enters into the other of the gas and the liquid by way of a mechanism selected from the group consisting of absorption, a chemical reaction and a combination thereof.

11. The gas-liquid exchange system according to any one of the preceding embodiments, wherein the membrane has a membrane density of from about 0.1%to 99.9%; or from about 1%to 99%; or from about 10%to about 75%; or from about 20%to about 50%.

12. The gas-liquid exchange system according to any one of the preceding embodiments, wherein the membrane is disposed over a structure selected from the group consisting of a substrate, a mould, a matrix and a combination thereof.

13. The gas-liquid exchange system according to embodiment 12, wherein the structure comprises a material selected from the group consisting of felt, fabric, netting, mesh, plastic, metal, glass, ceramic, carbon fiber and a combination thereof.

14. The gas-liquid exchange system according to any one of embodiment 12 or 13, wherein the membrane is disposed over the structure in such a matter that at least a portion of the structure is not covered by the membrane.

15. The gas-liquid exchange system according to any one of embodiments 12 to 14, wherein the structure comprises at least one pore that is not filled by the membrane.

16. The gas-liquid exchange system according to any one of embodiments 12 to 15, wherein the structure comprises a micro structured material having a pore size of about 0.01 to about 2000 microns; or about 1 to about 500 microns; or about 10 to about 100 microns.

17. The gas-liquid exchange system according to any one of embodiments 12 to 15, wherein the membrane comprises a plurality of individual pieces that are not interconnected with one another.

18. The gas-liquid exchange system according to any one of the preceding embodiments, wherein at least one of a length, width and diameter of the membrane is based on a factor selected from the group consisting of flow rate, the amount of mass transfer exchange required, the system lifetime, and a combination thereof.

19. The gas-liquid exchange system according to any one of the preceding embodiments, wherein the membrane is configured to comprise a plurality of tubes; or hollow tubes.

20. The gas-liquid exchange system according to any one of the preceding embodiments, wherein the membrane comprises a first thickness and a second thickness, and where the first thickness is different from the second thickness.

21. The gas-liquid exchange system according to any one of the preceding embodiments, wherein the membrane is from about 0.5 μm to about 2000 μm thick; or from about 4 μm to about 500 μm thick; or from about 10 μm to about 150 μm thick; or from about 25 μm to about 100 μm thick.

22. The gas-liquid exchange system according to any one of the preceding embodiments, wherein the membrane comprises a material selected from the group consisting of a linear polymer, a branched polymer, an interpenetrating polymer network and a combination thereof.

23. The gas-liquid exchange system according to any one of the preceding embodiments, wherein the membrane comprises a monomer selected from the group consisting of a (C1-16) alkylacrylate, a (C1-16) alkyl methacrylate, a (C1-12) alkylmaleic acid ester, a (C1-12) alkyl (C6-12) aryl urethane oligomer, a (C1-12) alkyl allyl urethane oligomer, a (C1-12) alkyl urethaneacrylate oligomer, a fluoro (C1-16) alkylacrylate, a fluoro (C1-16) alkyl methacrylates, and a combination thereof.

24. The gas-liquid exchange system according to any one of the preceding embodiments, wherein the membrane comprises a polymer selected from the group consisting of an oleophobic polymer, a water-insoluble polymer, and a combination thereof.

25. The gas-liquid exchange system according to any one of the preceding embodiments, wherein the membrane comprises a polymer selected from the group consisting of a poly (N- alkyl (meth) acrylamide) ; a poly (N-vinylalkylamide) ; a poly (N-vinylpyrrolidone) ; a poly (2-alkyl-2-oxazoline) ; a polyvinyl alkyl ether; a copolymer of polyethylene oxide and polypropylene oxide; a poly (oxyethylene vinyl ether) ; a cellulose derivative; and a copolymer of the above polymers; a N-alkyl (meth) acrylamide; a N-vinylalkylamide; a vinyl alkyl ether; ethylene oxide and propylene oxide; a 2-alkyl-2-oxazoline; and a combination thereof.

26. The gas-liquid exchange system according to embodiment 24, wherein

A) the poly (N-alkyl (meth) acrylamide) is selected from the group consisting of poly (N-isopropyl (meth) acrylamide) , poly (N-n-propyl (meth) acrylamide) , poly (N-methyl (meth) acrylamide) , poly (N-ethyl (meth) acrylamide) , poly (N-n-butyl (meth) acrylamide) , poly (N-isobutyl (meth) acrylamide) , poly (N-t-butyl (meth) acrylamide) and a combination thereof;

B) the poly (N-vinylalkylamide) is selected from the group consisting of poly (N-vinylisopropylamide) , poly (N-vinyl n-propylamide) , poly (N-vinyl n-butylamide) , poly (N-vinylisobutylamide) , poly (N-vinyl-t-butylamide) and a combination thereof;

C) the poly (2-alkyl-2-oxazoline) is selected from the group consisting of poly (2-ethyl-2-oxazoline) , poly (2-isopropyl-2-oxazoline) , poly (2-n-propyl-2-oxazoline) and a combination thereof;

D) the polyvinyl alkyl ether is selected from the group consisting of polyvinyl methyl ether, polyvinyl ethyl ether and a combination thereof;

E) the cellulose derivative is selected from the group consisting of methyl cellulose, ethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose and combination thereof;

F) the N-alkyl (meth) acrylamide is selected from the group consisting of N-isopropyl (meth) acrylamide, N-n-propyl (meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-n-butyl (meth) acrylamide, N-isobutyl (meth) acrylamide, N-t-butyl (meth) acrylamide and a combination thereof;

G) the N-vinylalkylamide is selected from the group consisting of N-vinylisopropylamide, N-vinyl n-propylamide, N-vinyl n-butylamide, N-vinylisobutylamide, N-vinyl-t-butylamide and a combination thereof;

H) the vinyl alkyl ether is selected from the group consisting of vinyl methyl ether, vinyl ethyl ether and a combination thereof; and

G) the 2-alkyl-2-oxazolines is selected from the group consisting of 2-ethyl-2-oxazoline, 2-isopropyl-2-oxazoline, 2-n-propyl-2-oxazoline and a combination thereof.

27. The gas-liquid exchange system according to any one of the preceding embodiments, wherein the membrane comprises a material selected from the group consisting of a homopolymer, a copolymer, a cross-linked polymer, a polymer with alternating units, a polymer with random units, a block polymer and a combination thereof.

28. The gas-liquid exchange system according to any one of the preceding embodiments, wherein the membrane comprises a filler selected from the group consisting of a reinforcing fiber, a conductive filler, a coupling agent, a nanoclay, a nanoparticle, a polymer and a combination thereof.

29. The gas-liquid exchange system according to embodiment 28, wherein

A) the reinforcing fiber is selected from the group consisting of boron, carbon, fibrous mineral, glass, poly paraphenylene terephthalamide, and a combination thereof;

B) the conductive filler is selected from the group consisting of aluminium powder, carbon fiber, graphite, and a combination thereof;

C) the coupling agent is selected from the group consisting of a silane, a titanite, and a combination thereof;

D) the nanoclay is selected from the group consisting of bentonite, halloysite, and a combination thereof;

E) the nanoparticle is selected from the group consisting of silicon dioxide, titanium dioxide, and a combination thereof; and

F) the polymer chain is selected from the group consisting of Poly (vinyl alcohol) , Carboxymethyl cellulose, and a combination thereof.

30. The gas-liquid exchange system according to any one of the preceding embodiments, wherein the membrane comprises an ionically crosslinked polymer; or an ionically crosslinked elastomer; or an ionically crosslinked polyisoprene elastomer.

31. A device for removal of an ingredient from a gas comprising the gas-liquid exchange system according to any one of the preceding embodiments.

32. A device for replenishing an ingredient in a liquid to a gas comprising the gas-liquid exchange system according to any one of embodiments 1 to 30.

33. An air purification and/or exchange system for a building comprising the gas-liquid exchange system according to any one of embodiments 1 to 30.

34. A device for vehicle exhaust emission comprising the gas-liquid exchange system according to any one of embodiments 1 to 30.

35. A ventilation system comprising the gas-liquid exchange system according to any one of embodiments 1 to 30.

36. Use of a gas-liquid exchange system according to any one of embodiments 1 to 30 for an operation selected from the group consisting of:

A) flue gas and off gas treatment;

B) acid gas removal from a Natural Gas and fuel mixture;

C) indoor air purification;

D) CO ₂ recovery;

E) mercury removal;

F) desulfurization of biogas;

G) palm oil deacidification;

H) iodide oxidation;

I) olefin/paraffin separation;

J) oxygenation/deoxygenation;

K) Gas humidity control;

L) volatilization of a product; and a combination thereof.

37. Use of a gas-liquid exchange system according any one of embodiments 1 to 30 in a device for discharging an exhaust gas from a source selected from the group consisting of a power plant, a manufacturing facility, a waste incinerator, a fireplace, an oven, a boiler, a smelter, a furnace, a steam generator, a car, a bus, a truck, a ship and a combination thereof.

38. Use of a gas-liquid exchange system according to embodiment 37, where the gas-liquid exchange system is in a location selected from the group consisting of an exhaust pipe, a flue gas stack, propelling nozzle and a combination thereof.

39. A method of conducting gas-liquid exchange, comprising

A) introducing a stream of a gas into a chamber comprising a membrane, wherein the membrane divides the chamber into at least a gas portion and a liquid portion with the gas portion receiving the gas, and wherein the membrane defines a flow path for the gas;

B) introducing a stream of a liquid to the liquid portion of the chamber, wherein the membrane contains the liquid within the liquid portion;

C) effecting contact between the gas and the liquid at the membrane, such that at least a portion of an ingredient in one of the gas and the liquid enters into the other of the gas and the liquid upon the contact,

D) discharging the gas out of the chamber; and discharging the liquid out of the chamber.

40. The method according to embodiment 39, further comprising applying the membrane in a liquid form over a structure selected from the group consisting of a substrate, a mould, a maxtrix and a combination thereof.

41. The method according to any one of embodiment 39 or 40, wherein the applying of the membrane is facilitated by an organic solvent selected from the group consisting of an alkane, a ketone, an ester, an ether, an alcohol and a combination thereof.

42. The method according to embodiment 41, wherein the organic solvent is selected from the group consisting of heptane, ethyl acetate, butyl acetate, isoamyl acetate, dioctyl adipate, acetone, methyl ethyl ketone, methyl isobutyl ketone, isopropanol, diethyl ether, mineral spirits, petroleum distillate, and a combination thereof.

43. The method according to any one of embodiments 40 t 42, wherein the applying of the membrane is conducted with a stabilizing agent, wherein the stabilizing agent is from about 5 wt%to about 50 wt%, or from about 15 wt%to about 25 wt%, by weight of the membrane.

44. The method according to embodiment 43, wherein the stabilizing agent is selected from the group consisting of deionized water, demineralized water and a combination thereof.

45. The method according to any one of embodiments 40 to 44, wherein a surface of the structure is treated before the formation of the membrane.

46. The method according to any one of embodiments 39 to 45, further comprising synthesizing the membrane by polymerization of a molecule selected from a monomer, an oligomer and a combination thereof,

47. The method according to any one of embodiments 39 to 45, further comprising synthesizing the membrane based on a polymer.

48. The method according to any one of embodiment 46 or 47, wherein the polymerization is conducted with a cross-linking agent selected from the group consisting of N, N′- Bisacrylamide, N, N′-BIS (ACRYLOYL) -CYSTAMINE, ethylenediamine, 1, 3-propanediamine, 1, 3-propanedithiol, dithiothreitol, dithioerythritol, 1, 5-pentanediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, propylenediamine, di (aminomethyl) ether, 1, 8-diamino-4- (aminomethyl) octane, xylylenediamine, hydroquinone, bisphenol A, bisphenol sulfone, 1, 4-butanedisulfinic acid, benzenedisulfinic acid, thioethanolamine, p-aminothiophenol, and butylenediamine, ethyleneglycol dimethacrylate, trimethylolpropane triacrylate, hexamethyleneglycol dimethacrylate, glycerol α, α’-diallylether, n-methylol acrylamide, vinylbenzene chloride, allyl chloride, gloxal, polyvinyl alcohol, polyethyleneimine, 1-vinylimidazole, hexadiene, tetraethylene glycol dimethacrylate, divinyl benzene, 1, 6-diaminohexane, p-phenylenediamine, ethylene glycoldi (meth) acrylate, propylene glycoldi (meth) acrylate, N, N′-methylenebis (meth) acrylamide, tolylene diisocyanate, divinylbenzene, and polyethylene glycoldi (meth) acrylate; glutaraldehyde; polyvalent alcohol; polyvalent amine; polyvalent carboxylic acid; a metal ion; and a combination thereof.

49. The method according to embodiment 48, wherein the metal ion is selected from the group consisting of a calcium ion, a zinc ion and a combination thereof.

50. The method according to any one of embodiments 39 to 49, wherein effecting contact between the gas and the liquid at the membrane comprises subjecting one or both of the gas and the liquid to a stimulus for promoting mass transfer selected from the group consisting of pressure, temperature, electric or magnetic field, light, sound, ultrasonic wave, pH, solvent composition, ionic strength, molecular species and a combination thereof.

51. The method according to any one of embodiments 39 to 50, wherein effecting contact between the gas and the liquid at the membrane comprises applying a first pressure to the gas and applying a second pressure to the liquid, such that the first pressure is different from the second pressure.

52. The method according to any one of embodiments 39 to 51, wherein effecting contact between the gas and the liquid at the membrane comprises controlling a flow rate of the gas and a flow rate of the liquid, such that the flow rate of the gas is different from the flow rate of the liquid.

53. The method according to any one of embodiments 39 to 52, wherein effecting contact between the gas and the liquid at the membrane comprises controlling a direction of gas and a direction of the liquid, such that at least one of the gas and the liquid flows in a direction perpendicular to the membrane.

54. The method according to any one of embodiments 39 to 53, wherein effecting contact between the gas and the liquid at the membrane takes place in a device for discharging a exhaust gas from a source selected from a power plant, a manufacturing facility, a waste incinerator, a fireplace, an oven, a boiler, a smelter, a furnace, a steam generator, a car, a bus, a truck, a ship and a combination thereof.

55. The method according to any one of embodiments 39 to 54, wherein effecting contact between the gas and the liquid at the membrane takes place in a location selected from the group consisting of an exhaust pipe, a flue gas stack, a propelling nozzle and a combination thereof.

56. The method according to any one of embodiments 39 to 55, further comprising, after the contact between the gas and the liquid, effecting gas-liquid exchange between one of the gas and the liquid and a stream of a third fluid, wherein the third fluid is in a gas form or a liquid form, the form of the third fluid being different from the form of the gas or liquid with which the third fluid is in gas and liquid exchange.

57. The method according to any one of embodiments 39 to 56, further comprising, after the contact between the gas and the liquid, subjecting one of the gas and the liquid to a treatment selected from the group consisting of oxidation, decarbonation, evaporation, distillation, evacuation, extraction, crystallization and a combination thereof.

58. The method according to any one of embodiments 39 to 57, effecting contact between the gas and the liquid at the membrane comprises organizing the gas and the liquid in same or counterflow directions.

59. The method according to any one of embodiments 39 to 58, further comprising, after the contact between the gas and the liquid, effecting additional contact between the gas and the liquid at an additional membrane within the chamber.

60. The method according to any one of embodiments 46 to 49, further comprising, prior to synthesizing the membrane, determining a membrane force density and a membrane density for the membrane such that the membrane forms gas-liquid interface and withstands differential pressure.

Claims

A gas-liquid exchange system for containing a gas and a liquid, comprising:

A) a chamber comprising;

i) a first inlet for introducing a stream of a gas into the chamber;

ii) a first outlet in fluid communication with the first inlet, through which the gas exits the chamber;

iii) a second inlet for directing a stream of a liquid into the chamber;

(iv) a second outlet in fluid communication with the second inlet, through which the liquid exits the chamber; and

v) a membrane within the chamber for gas-liquid contact, wherein the membrane divides the chamber into at least a gas portion and a liquid portion, the gas portion receiving the gas from the first inlet and discharging the gas via the first outlet, and the liquid portion receiving the liquid from the second inlet and discharging the liquid via the second outlet,

characterized in that the membrane contains the liquid within the liquid portion and that the membrane at least partly defines a flow path for the gas within the chamber, wherein the gas and the liquid are in contact at the membrane and at least a portion of an ingredient in one of the gas and the liquid enters into the other of gas and the liquid upon the contact.
The gas-liquid exchange system according to claim 1, wherein the membrane comprises a three-dimensional network comprising a material selected from the group consisting of a polymer, a fiber and a combination thereof, wherein the membrane contains the liquid within the liquid portion through an intermolecular attractive force.
The gas-liquid exchange system according to any one of the preceding claims, wherein the gas comes from a source selected from the group consisting of combustion, ventilation, manufacturing, air and a combination thereof.
The gas-liquid exchange system according to any one of the preceding claims, wherein the liquid is selected from the group consisting of a polar solvent, a non-polar solvent, an ionic liquid and a combination thereof.
The gas-liquid exchange system according to any one of the preceding claims, wherein the membrane has a membrane density of from about 0.1%to 99.9%; or from about 1%to 99%; or from about 10%to about 75%; or from about 20%to about 50%.
The gas-liquid exchange system according to any one of the preceding claims, wherein the membrane is disposed over a structure selected from the group consisting of a substrate, a mould, a matrix and a combination thereof.
The gas-liquid exchange system according to any one of the preceding claims, wherein the membrane comprises a first thickness and a second thickness, and where the first thickness is different from the second thickness.
The gas-liquid exchange system according to any one of the preceding claims, wherein the membrane comprises a filler selected from the group consisting of a reinforcing fiber, a conductive filler, a coupling agent, a nanoclay, a nanoparticle, a polymer and a combination thereof.
The gas-liquid exchange system according to any one of the preceding claims, wherein the membrane comprises an ionically crosslinked polymer; or an ionically crosslinked elastomer; or an ionically crosslinked polyisoprene elastomer.
A device for removal of an ingredient from a gas comprising the gas-liquid exchange system according to any one of the preceding claims.
A device for replenishing an ingredient in a liquid to a gas comprising the gas-liquid exchange system according to any one of claims 1 to 9.
Use of a gas-liquid exchange system according to any one of claims 1 to 9 for an operation selected from the group consisting of:

A) flue gas and off gas treatment;

B) acid gas removal from a Natural Gas and fuel mixture;

C) indoor air purification;

D) CO ₂ recovery;

E) mercury removal;

F) desulfurization of biogas;

G) palm oil deacidification;

H) iodide oxidation;

I) olefin/paraffin separation;

J) oxygenation/deoxygenation;

K) Gas humidity control;

L) volatilization of a product; and a combination thereof.
A method of conducting gas-liquid exchange, comprising

A) introducing a stream of a gas into a chamber comprising a membrane, wherein the membrane divides the chamber into at least a gas portion and a liquid portion with the gas portion receiving the gas, and wherein the membrane defines a flow path for the gas;

B) introducing a stream of a liquid to the liquid portion of the chamber, wherein the membrane contains the liquid within the liquid portion;

C) effecting contact between the gas and the liquid at the membrane, such that at least a portion of an ingredient in one of the gas and the liquid enters into the other of the gas and the liquid upon the contact,

D) discharging the gas out of the chamber; and

discharging the liquid out of the chamber.
The method according to claim 13, further comprising synthesizing the membrane with a cross-lining agent selected from the group consisting of N, N′-Bisacrylamide, N, N′-BIS (ACRYLOYL) -CYSTAMINE, ethylenediamine, 1, 3-propanediamine, 1, 3-propanedithiol, dithiothreitol, dithioerythritol, 1, 5-pentanediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, propylenediamine, di (aminomethyl) ether, 1, 8-diamino-4- (aminomethyl) octane, xylylenediamine, hydroquinone, bisphenol A, bisphenol sulfone, 1, 4-butanedisulfinic acid, benzenedisulfinic acid, thioethanolamine, p- aminothiophenol, and butylenediamine, ethyleneglycol dimethacrylate, trimethylolpropane triacrylate, hexamethyleneglycol dimethacrylate, glycerol α, α’-diallylether, n-methylol acrylamide, vinylbenzene chloride, allyl chloride, gloxal, polyvinyl alcohol, polyethyleneimine, 1-vinylimidazole, hexadiene, tetraethylene glycol dimethacrylate, divinyl benzene, 1, 6-diaminohexane, p-phenylenediamine, ethylene glycoldi (meth) acrylate, propylene glycoldi (meth) acrylate, N, N′-methylenebis (meth) acrylamide, tolylene diisocyanate, divinylbenzene, and polyethylene glycoldi (meth) acrylate; glutaraldehyde; polyvalent alcohol; polyvalent amine; polyvalent carboxylic acid; a metal ion; and a combination thereof.
The method according to any one of claim 13 or 14, wherein effecting contact between the gas and the liquid at the membrane comprises subjecting one or both of the gas and the liquid to a stimulus for promoting mass transfer selected from the group consisting of pressure, temperature, electric or magnetic field, light, sound, ultrasonic wave, pH, solvent composition, ionic strength, molecular species and a combination thereof.
The method according to any one of claims 13 to 15, wherein effecting contact between the gas and the liquid at the membrane comprises applying a first pressure to the gas and applying a second pressure to the liquid, such that the first pressure is different from the second pressure.
The method according to any one of claims 13 to 16, wherein effecting contact between the gas and the liquid at the membrane takes place in a device for discharging a exhaust gas from a source selected from a power plant, a manufacturing facility, a waste incinerator, a fireplace, an oven, a boiler, a smelter, a furnace, a steam generator, a car, a bus, a truck, a ship and a combination thereof.
The method according to any one of claims 13 to 17, further comprising, after the contact between the gas and the liquid, effecting gas-liquid exchange between one of the gas and the liquid and a stream of a third fluid, wherein the third fluid is in a gas form or a liquid form, the form of the third fluid being different from the form of the gas or liquid with which the third fluid is in gas and liquid exchange.
The method according to any one of claims 13 to 18, further comprising, after the contact between the gas and the liquid, subjecting one of the gas and the liquid to a treatment selected from the group consisting of oxidation, decarbonation, evaporation, distillation, evacuation, extraction, crystallization and a combination thereof.
The method according to any one of claims 13 to 19, further comprising, prior to synthesizing the membrane, determining a membrane force density and a membrane density for the membrane such that the membrane forms gas-liquid interface and withstands differential pressure.