A gas-liquid reverse transport system and method based on solid / liquid phase change

Abstract

The application belongs to the technical field of controllable gas-liquid transport, and discloses a gas-liquid reverse transport system and method based on solid / liquid phase change, wherein the gas-liquid reverse transport system comprises a mixed fluid channel, a transport control unit, a first single-phase fluid channel and a second single-phase fluid channel; the mixed fluid channel contains a gas-liquid two-phase mixture or a passage gas; the transport control unit is composed of a solid / liquid phase change functional fluid and a porous membrane and respectively forms a solid-solid composite membrane and a liquid-solid composite membrane through stimulation response; the solid / liquid phase change functional fluid can selectively regulate the gas or liquid transmembrane transport by acting on the transport mixed fluid; the first single-phase fluid channel contains one-phase matter transported across the membrane; and the second single-phase fluid channel contains another-phase matter not transported across the membrane. The application has no limitation on the selection of membrane materials and the stimulation mode, and has universality in membrane separation technology. The application has the characteristics of low cost, simple operation and easy industrialization integration.

Description

Technical Field

[0001] This invention belongs to the field of gas-liquid controllable transport technology, specifically relating to a gas-liquid reversal transport system and method based on solid / liquid phase change. Background Technology

[0002] Selective transport of gases and liquids involves a wide range of technological applications, from protective clothing and water purification to food processing and fuel cells, as well as emerging fields such as sustainable power generation and electrochemical fuel production. Membrane separation technology has developed rapidly in recent years. Currently, most methods for selective gas-liquid transmembrane transport allow gas permeation while blocking external liquids. Common water and gas separation typically uses hydrophobic microporous membranes, whose pore sizes fall between the diameter of a water droplet (>100 μm) and that of gas molecules (<1 nm), or non-porous / dense hydrophilic membranes that primarily separate through solution diffusion mechanisms.

[0003] Typically, membranes that allow liquids to pass through while retaining gases are counterintuitive and uncommon, but in some applications, timely removal of water from the system is essential. For example, water, as a reaction product in proton exchange membrane fuel cells or a byproduct of CO2 hydrogenation to form liquid fuel, strongly inhibits the kinetics and thermodynamics of the catalytic process. Constructing a gas-barrier, water-permeable membrane can improve the reaction rate by removing water while retaining reactant gases. Experimental strategies for achieving high water permeability while repelling gas molecules typically include molecular sieve membranes and hydrophilic porous membranes. The former selectively permeates water due to the high polarity of water molecules, which preferentially adsorbs other components and blocks transport channels, while the latter is based on the presence of a water meniscus to balance transmembrane pressure and the surface tension of water.

[0004] In gas-liquid selective transport processes, the above-mentioned separation membranes all possess only one fixed selective transport function, namely, selectively allowing one phase of the liquid or gas to pass through while blocking the other phase. However, for a wider range of applications, selective transport membranes with a single fixed function are insufficient. Therefore, developing novel gas-liquid reversal transport technology that can selectively and controllably transport either the gas or liquid phase across the membrane according to actual application requirements will be of great significance for the industrial application of membrane separation technology and the miniaturization and portability of engineering processes. Summary of the Invention

[0005] The purpose of this invention is to overcome the deficiencies of the existing technology and provide a gas-liquid reversal transport system and method based on solid / liquid phase change. This system utilizes a solid / liquid phase change functional fluid combined with a porous membrane. In response to an applied stimulus, when the solid / liquid phase change functional fluid is in a liquid state, the formed liquid-solid composite membrane allows the liquid in the transported gas-liquid mixture to cross the membrane, while the gas is blocked. Conversely, when the solid / liquid phase change functional fluid is in a solid state, the formed solid-solid composite membrane allows the gas in the transported gas-liquid mixture to cross the membrane, while the liquid is blocked, thus achieving gas-liquid reversal transport and separation.

[0006] To achieve the above objectives, one of the technical solutions of the present invention is: a gas-liquid reversal transport system based on solid / liquid phase change, comprising a mixed fluid channel, a transport control unit, a first single-phase fluid channel, and a second single-phase fluid channel. The mixed fluid channel contains a gas-liquid two-phase mixture or a channel gas. The transport control unit is composed of a solid / liquid phase change functional fluid and a porous membrane, and respectively forms a solid-solid composite membrane and a liquid-solid composite membrane through stimulation response. The solid / liquid phase change functional fluid can interact with the transport mixed fluid to selectively regulate the gas or liquid transmembrane transport. The first single-phase fluid channel contains one phase of material transported across the membrane. The second single-phase fluid channel contains another phase of material that does not cross the membrane.

[0007] Optionally, the gas-liquid two-phase mixture in the mixed fluid channel may be a mixture of one of the gas phases such as air, oxygen, nitrogen, carbon dioxide, and ammonia, and one of the liquid phases such as water, methanol, ethanol, edible oil, alkanes, alkenes, and aromatic hydrocarbons.

[0008] Optionally, the gas in the passage can be one of the following gas phases: air, oxygen, nitrogen, carbon dioxide, ammonia, etc.

[0009] Optionally, the solid / liquid phase change functional fluid includes, but is not limited to, one of the following: paraffin wax, a mixture of solid and liquid paraffin wax, ice, corn starch suspension, shear thickening fluid, sodium acetate supersaturated solution, ammonium sulfate solution, inorganic hydrated salt phase change material, and bio-based organic phase change material.

[0010] Optionally, the porous membrane may include, but is not limited to, one of copper mesh, nickel mesh, stainless steel mesh, nylon mesh, etc.

[0011] Optionally, the pore size of the porous membrane is 1-100 μm.

[0012] Optionally, the solid / liquid phase change functional fluid responds to a change from solid to liquid state when a stimulus is applied, and the applied stimulus includes at least one of light, heat, electricity, magnetism, mechanical vibration, or the addition of seed crystals.

[0013] Optionally, the solid / liquid phase change functional fluid has a stronger affinity for the porous membrane than the liquid in the two-phase mixture has an affinity for the porous membrane.

[0014] Optionally, the gas-liquid reversal transport system further includes a sealing clamp, in which the transport control unit is encapsulated; the mixing fluid channel and the first single-phase fluid channel are located on the front side of the sealing clamp, and the second single-phase fluid channel is located on the rear side of the sealing clamp.

[0015] Optionally, the mixing fluid channel is interconnected with the first single-phase fluid channel.

[0016] To achieve the above objectives, the second technical solution of the present invention is: a gas-liquid reversal transport method based on solid / liquid phase change, specifically including the following steps: selecting a solid / liquid phase change functional fluid in a liquid state to combine with a porous membrane to form a liquid-solid composite membrane for the transport control unit; driving the gas-liquid two-phase mixture in the mixing fluid channel by pressure; liquid transmembrane transport flowing out from the second single-phase fluid channel, and gas flowing out from the first single-phase fluid channel; driving the passage gas in the mixing fluid channel by pressure, while simultaneously applying a stimulus to cause the solid / liquid phase change fluid to transform into a solid state, combining with the porous membrane to form a solid-solid composite membrane for the transport control unit; driving the gas-liquid two-phase mixture in the mixing fluid channel by pressure; gas transmembrane transport flowing out from the second single-phase fluid channel, and liquid flowing out from the first single-phase fluid channel, the gas and liquid are reversed for transport, and the transport state dynamically switches with the applied stimulus.

[0017] Optionally, the flow rate of the gas-liquid two-phase mixture in the mixing fluid channel is 0.01-20 mL / min.

[0018] Optionally, the flow rate of the gas in the mixed fluid channel is 1-50 mL / min.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] 1. This invention is based on the combination of a functional fluid with a solid / liquid phase change and a porous membrane, and achieves the gas-liquid reversal transport function in a single system by applying stimulation.

[0021] 2. The present invention uses a functional fluid to avoid contact between the transport fluid and the porous membrane surface, thus giving the composite membrane excellent antifouling properties.

[0022] 3. This invention does not restrict the selection of membrane materials or the method of applying stimulation, and the membrane separation technology has universality.

[0023] 4. The gas-liquid two-phase mixed fluid and the solid / liquid phase change functional fluid in this invention can be selected according to different application requirements, and have a wide range of applications.

[0024] 5. This invention features low cost, simple operation, and easy industrial integration. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the gas-liquid reversal transport device according to an embodiment of the present invention. ，

[0026] Wherein: 1-Transport control unit, 2-Mixed fluid channel, 3-First single-phase fluid channel, 4-Second single-phase fluid channel, 5-Sealing clamp, 51-Clamping material, 52-Sealing material;

[0027] Figure 2 This is a schematic diagram illustrating the principle of gas-liquid reversal transport technology according to an embodiment of the present invention.

[0028] Among them: 11-solid / liquid phase change functional fluid, 12-porous membrane;

[0029] Figure 3 This is a photograph of the liquid flowing out and the gas blocking it in Example 1;

[0030] Figure 4 This is a photograph of the gas flow obstructed by the liquid in Example 1;

[0031] Figure 5 This is a comparison of the pressure thresholds of the stainless steel mesh impregnated with paraffin, the functional fluid of solid / liquid phase change, and the stainless steel mesh under different temperature conditions in Example 1.

[0032] Figure 6 This is a graph showing the relationship between the gas flow rate in the passage and the liquid pressure threshold of the solid-solid composite membrane in Example 1. Detailed Implementation

[0033] To make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be described in more detail below with reference to the accompanying drawings and specific embodiments, but the scope of protection of the present invention is not limited to these embodiments.

[0034] Example 1

[0035] A gas-liquid inversion transport system based on solid / liquid phase change, such as Figure 1As shown, the system includes a transport control unit 1, a mixing fluid channel 2, a first single-phase fluid channel 3, a second single-phase fluid channel 4, and a sealing clamping member 5. The transport control unit 1 includes a solid / liquid phase change functional fluid 11 and a porous membrane 12. The sealing clamping member 5 includes two clamping materials 51 and a sealing material 52. The two clamping materials 51 and the sealing material 52 cooperate to form a chamber for housing the transport control unit 1 and are completely sealed. The transport control unit 1 is located in the communication path between the mixing fluid channel 2 and the second single-phase fluid channel 4, and the two clamping materials 51 achieve a sealed connection between the mixing fluid channel 2 and the second single-phase fluid channel 4. That is, the transport control unit 1 is located inside the chamber, and the mixing fluid channel 2 and the second single-phase fluid channel 4 are located on both sides of the transport control unit 1 and are connected to it. The first single-phase fluid channel 3 and the mixing fluid channel 2 are located on the same side of the transport control unit 1 and are interconnected. The solid / liquid phase change functional fluid 11 and the transported gas-liquid two-phase mixture are immiscible.

[0036] The principle of gas-liquid reversal transport is as follows: Figure 2 As shown, when the solid / liquid phase change functional fluid 11 in the transport control unit 1 is in a liquid state, it forms a liquid-solid composite membrane with the porous membrane 12. At this time, the transported gas, due to its compressibility and interaction with the functional liquid interface, has a higher threshold pressure than the transported liquid, causing the liquid to flow out through the second single-phase fluid channel, while the gas flows out through the first single-phase fluid channel. When the solid / liquid phase change functional fluid 11 in the transport control unit 1 is in a solid state, it forms a solid-solid composite membrane with the porous membrane 12. At this time, the transported gas molecules are much smaller than the membrane pore size, resulting in a lower threshold pressure than the transported liquid, causing the gas to flow out through the second single-phase fluid channel, while the liquid flows out through the first single-phase fluid channel.

[0037] A thermally responsive gas-liquid inversion transport method:

[0038] Using the aforementioned gas-liquid reversal transport system, 58# paraffin wax was selected as the solid / liquid phase change functional fluid. In its liquid state, it was used to wet a 5μm stainless steel mesh, forming a liquid-solid composite membrane in the transport control unit. A two-phase mixture of air and ultrapure water was driven through the mixing fluid channel by pressure, with a flow rate of 1 mL / min and a mixing volume ratio of 1:1. Figure 3 As shown, at an ambient temperature of 65°C, ultrapure water flows out through the second single-phase fluid channel, while air flows out through the first single-phase fluid channel. Air in the mixed fluid channel is pressure-driven at a flow rate of 10 mL / min, while the ambient temperature is lowered to 25°C, causing the paraffin to change from a liquid to a solid state, forming a solid-solid composite membrane with the stainless steel mesh, thus constituting the transport control unit. Figure 4As shown, under the same conditions, the air and ultrapure water two-phase mixture in the mixed fluid channel is driven by pressure. At this time, the air is transported across the membrane and flows out from the second single-phase fluid channel, while the ultrapure water flows out from the first single-phase fluid channel. The air and ultrapure water can be transported in reverse, and the transport state can be dynamically switched according to the applied temperature stimulus. The system realizes thermally responsive gas-liquid reverse transport.

[0039] Figure 5 This is a comparison of the pressure thresholds of the stainless steel mesh impregnated with paraffin, the functional fluid for solid / liquid phase change, and the stainless steel mesh under different temperature conditions in Example 1. From... Figure 5 It can be seen that for stainless steel mesh, at both high temperature (65℃) and low temperature (25℃), the gas pressure threshold is 0, making gas transport uncontrollable. Furthermore, the liquid pressure threshold is always higher than that of the gas, making gas-liquid reversal transport impossible. However, for stainless steel mesh impregnated with paraffin, a functional fluid undergoing solid / liquid phase change, in the high-temperature liquid-solid composite membrane state, the gas threshold pressure is 5.10±0.26kPa, the liquid threshold pressure is 3.61±0.22kPa, and the pressure difference between the gas and liquid is 1.49kPa, exhibiting typical liquid permeability and gas barrier functions. In the low-temperature solid-solid composite membrane state, the gas threshold pressure drops to 0.29±0.04kPa, the liquid threshold pressure rises to 8.08±0.64kPa, and the pressure difference between the gas and liquid is -7.79kPa, exhibiting gas permeability and liquid barrier functions. Figure 6 This is a graph showing the relationship between the gas flow rate in the passage and the liquid pressure threshold of the solid-solid composite membrane in Example 1. Figure 6 It can be seen that the lower the flow rate of the gas in the passage during the cooling process, the higher the pressure threshold of the liquid transported by the solid-solid composite membrane after cooling, and both are higher than the pressure threshold of the gas.

[0040] Example 2

[0041] A gas-liquid inversion transport method based on electric field response:

[0042] Using the gas-liquid inversion transport system described in Example 1, a mixture of 58# paraffin and liquid paraffin at a volume ratio of 1:2.5 was selected as the solid / liquid phase change functional fluid. In its liquid state, this fluid impregnates a 10μm stainless steel mesh modified with electrothermal effect materials (including but not limited to noble metal nanoparticles, carbon-based materials, and polypyrrole), forming a liquid-solid composite membrane for the transport control unit. The air and ultrapure water two-phase mixture in the mixing fluid channel is driven by pressure at a flow rate of 0.5 mL / min. Under a certain electric field, ultrapure water is transported across the membrane from the second single-phase fluid channel, while air flows out from the first single-phase fluid channel. The air in the mixing fluid channel is driven by pressure at a flow rate of 10 mL / min, while the electric field is simultaneously turned off, causing the paraffin to change from a liquid to a solid state, thus forming a solid-solid composite membrane with the stainless steel mesh for the transport control unit. Under the same conditions, the air and ultrapure water two-phase mixture in the mixed fluid channel is driven by pressure. Air is transported across the membrane and flows out from the second single-phase fluid channel, while ultrapure water flows out from the first single-phase fluid channel. The air and ultrapure water are transported in reverse, and the transport state can be dynamically switched with the application of an electric field.

[0043] Example 3

[0044] A photoresponsive gas-liquid inversion transport method:

[0045] Using the gas-liquid reversal transport system described in Example 1, 58# paraffin wax was selected as the solid / liquid phase change functional fluid. In its liquid state, it impregnates a 5μm stainless steel mesh modified with photoresponsive molecules (including but not limited to azobenzene derivatives, spirocyclic pyran derivatives, and triphenylmethyl derivatives) to form a liquid-solid composite membrane for the transport control unit. A two-phase mixture of carbon dioxide and edible oil in the mixing fluid channel is driven by pressure at a flow rate of 1 mL / min. Under light irradiation, edible oil is transported across the membrane from the second single-phase fluid channel, while carbon dioxide flows out from the first single-phase fluid channel. Carbon dioxide in the mixing fluid channel is then driven by pressure at a flow rate of 20 mL / min, while the light source is turned off, causing the paraffin wax to change from liquid to solid, forming a solid-solid composite membrane with the stainless steel mesh for the transport control unit. Under the same conditions, the two-phase mixture of carbon dioxide and edible oil in the mixing fluid channel is driven by pressure. Carbon dioxide is transported across the membrane from the second single-phase fluid channel, while edible oil flows out from the first single-phase fluid channel. The carbon dioxide and edible oil are transported in reverse, and the transport state can be dynamically switched according to the applied light source stimulation.

[0046] Example 4

[0047] A gas-liquid inversion transport method responsive to seed crystal stimulation:

[0048] Using the gas-liquid reversal transport system from Example 1, a supersaturated sodium acetate solution was selected as the solid / liquid phase change functional fluid. In its liquid state, it impregnates a 20 μm nylon mesh to form a liquid-solid composite membrane for the transport control unit. A nitrogen and dodecane two-phase mixture in the mixing fluid channel is driven by pressure at a flow rate of 1 mL / min. Dodecane is transported across the membrane from the second single-phase fluid channel, while nitrogen flows out from the first single-phase fluid channel. Nitrogen in the mixing fluid channel is then driven by pressure at a flow rate of 20 mL / min, and sodium acetate crystals are added simultaneously. The sodium acetate solution changes from liquid to solid, combining with the nylon mesh to form a solid-solid composite membrane for the transport control unit. Under the same conditions, the nitrogen and dodecane two-phase mixture in the mixing fluid channel is driven by pressure. Nitrogen is transported across the membrane from the second single-phase fluid channel, while dodecane flows out from the first single-phase fluid channel. The nitrogen and dodecane are transported in reverse, and the transport state can be dynamically switched with the addition of seed crystals and solvent water stimulation.

[0049] Example 5

[0050] A gas-liquid reversal transport method based on sound field response:

[0051] Using the gas-liquid reversal transport system from Example 1, a corn starch suspension with a mass fraction of 42% was selected as the solid / liquid phase change functional fluid. In its liquid state, it wetted a 20 μm copper mesh to form a liquid-solid composite membrane for the transport control unit. A nitrogen and dodecane two-phase mixture in the mixing fluid channel was driven by pressure at a flow rate of 0.5 mL / min. Without an acoustic field, dodecane was transported across the membrane from the second single-phase fluid channel, while nitrogen flowed from the first single-phase fluid channel. When nitrogen in the mixing fluid channel was driven by pressure at a flow rate of 20 mL / min, and an acoustic field was applied, the corn starch suspension changed from a liquid to a near-solid state, combining with the copper mesh to form the solid-solid composite membrane for the transport control unit. Under the same conditions, the nitrogen and dodecane two-phase mixture in the mixing fluid channel was driven by pressure. Nitrogen was transported across the membrane from the second single-phase fluid channel, while dodecane flowed from the first single-phase fluid channel. The nitrogen and dodecane were transported in reverse, and the transport state could be dynamically switched according to the applied acoustic field stimulation.

[0052] The above embodiments are only used to further illustrate a gas-liquid reversal transport system and method based on solid / liquid phase change of the present invention. However, the present invention is not limited to the embodiments. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A gas-liquid reversal transport system based on solid / liquid phase change, characterized in that, The system includes a mixed fluid channel, a transport control unit, a first single-phase fluid channel, and a second single-phase fluid channel. The mixed fluid channel contains a gas-liquid two-phase mixture or a channel gas. The transport control unit is composed of a solid / liquid phase change functional fluid and a porous membrane, and forms a solid-solid composite membrane and a liquid-solid composite membrane respectively through stimulus response. The solid / liquid phase change functional fluid can interact with the transport mixed fluid to selectively regulate the transmembrane transport of gas or liquid. The first single-phase fluid channel contains one phase of material transported across the membrane. The second single-phase fluid channel contains another phase of material that does not cross the membrane. The solid / liquid phase change functional fluid has a stronger affinity for the porous membrane than the liquid in the two-phase mixture has an affinity for the porous membrane. The liquid-solid composite membrane is formed by the solid / liquid phase change functional fluid in the liquid state combining with the porous membrane. The gas-liquid two-phase mixture in the pressure-driven mixing fluid channel, where the liquid pressure threshold is lower than that of the gas, allows the liquid to selectively cross the membrane and flow out from the second single-phase fluid channel, while the gas flows out from the first single-phase fluid channel, achieving liquid permeability and gas barrier. The solid-solid composite membrane is formed by pressure-driven gas in the mixing fluid channel, while applying stimulation to transform the solid / liquid phase change fluid into a solid state, which is then combined with a porous membrane. The gas-liquid two-phase mixture in the mixing fluid channel is also pressure-driven, where the gas pressure threshold is lower than that of the liquid. Gas cross-membrane transport flows out from the second single-phase fluid channel, while the liquid flows out from the first single-phase fluid channel, achieving gas permeability and liquid barrier. The membrane morphology of the transport control unit dynamically switches between the liquid-solid composite membrane and the solid-solid composite membrane according to the applied stimulation, achieving reversible gas-liquid transport.

2. The gas-liquid reversal transport system as described in claim 1, characterized in that, The gas phase in the gas-liquid two-phase mixture in the mixed fluid channel is one of air, oxygen, nitrogen, carbon dioxide, and ammonia; the liquid phase in the gas-liquid two-phase mixture in the mixed fluid channel is one of water, methanol, ethanol, edible oil, alkanes, alkenes, and aromatic hydrocarbons; and the gas in the passage is one of air, oxygen, nitrogen, carbon dioxide, and ammonia.

3. The gas-liquid reversal transport system as described in claim 1, characterized in that, The solid / liquid phase change functional fluid includes, but is not limited to, one of the following: paraffin wax, a mixture of solid and liquid paraffin wax, ice, corn starch suspension, shear thickening fluid, sodium acetate supersaturated solution, ammonium sulfate solution, inorganic hydrated salt phase change material, and bio-based organic phase change material.

4. The gas-liquid reversal transport system as described in claim 1, characterized in that, The porous membrane includes, but is not limited to, one of copper mesh, nickel mesh, stainless steel mesh, and nylon mesh, and the pore size of the porous membrane is 1-100 μm.

5. The gas-liquid reversal transport system as described in claim 1, characterized in that, The solid / liquid phase change functional fluid responds by changing from a solid to a liquid state when subjected to at least one of the following stimuli: light, heat, electricity, magnetism, mechanical vibration, or the addition of seed crystals.

6. The gas-liquid reversal transport system as described in claim 1, characterized in that, The gas-liquid reversal transport system further includes a sealing clamp, the transport control unit is encapsulated in the sealing clamp, the mixed fluid channel and the first single-phase fluid channel are located on the front side of the sealing clamp, and the second single-phase fluid channel is located on the rear side of the sealing clamp.

7. The gas-liquid reversal transport system as described in claim 1, characterized in that, The mixed fluid channel is interconnected with the first single-phase fluid channel.

8. A gas-liquid reversal transport method based on the gas-liquid reversal transport system as described in any one of claims 1-7, characterized in that, Includes the following steps: The solid / liquid phase change functional fluid is selected to combine with a porous membrane in the liquid state to form a liquid-solid composite membrane for the transport control unit; the gas-liquid two-phase mixture in the mixing fluid channel is driven by pressure; the liquid flows out from the second single-phase fluid channel and the gas flows out from the first single-phase fluid channel through the membrane; the gas in the mixing fluid channel is driven by pressure, and a stimulus is applied to cause the solid / liquid phase change fluid to change to solid state, which then combines with the porous membrane to form a solid-solid composite membrane for the transport control unit; the gas-liquid two-phase mixture in the mixing fluid channel is driven by pressure; the gas flows out from the second single-phase fluid channel and the liquid flows out from the first single-phase fluid channel through the membrane, and the gas and liquid are transported in reverse, and the transport state is dynamically switched according to the applied stimulus.

9. The gas-liquid reversal transport method as described in claim 8, characterized in that, The flow rate of the gas-liquid two-phase mixture in the mixing fluid channel is 0.01-20 mL / min, and the flow rate of the gas in the passage is 1-50 mL / min.

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