Salt water evaporation and separation device capable of accelerating evaporation, salt water evaporation and separation method and application

Abstract

The invention relates to the field of salt-containing water treatment, and discloses a salt water evaporation and separation device capable of accelerating evaporation, a salt water evaporation and separation method and application. The brine evaporation and separation device comprises a feeding assembly, an evaporation and separation assembly, a salt collection assembly and a condensate water collection assembly, wherein the evaporation separation assembly comprises an ultra-spreading polypropylene fiber membrane; wherein the saline water can be subjected to ultra-spreading on the surface of the ultra-spreading polypropylene fiber membrane, and then water vapor and separated-out salt are obtained through evaporation; the salt collecting assembly and the condensate water collecting assembly are respectively used for collecting the salt and the water vapor. According to the saline water separation device disclosed by the invention, by utilizing the excellent spreading performance and the large specific surface area of the super-spreading fiber membrane, when saline water is spread in the fiber membrane, rapid evaporation of water can be realized, and after the salt reaches the saturated concentration, crystals are separated out and are easy to collect, so that efficient saline water separation is realized.

Description

Technical Field

[0001] The present invention relates to the field of salt water treatment, and in particular to a salt water evaporation separation device for accelerating evaporation, a salt water evaporation separation method and an application thereof, which can be used in the fields of seawater desalination, concentrated salt water treatment in chemical plants, etc. Background Art

[0003] There is a large amount of water on the earth's surface, but about 97% of it is seawater or brine, which has a high salt content and cannot be directly consumed. There is also a large amount of saline wastewater in industrial wastewater. In order to solve the problem of the lack of existing freshwater resources and the pollution of saline wastewater, it is of great significance to separate salt and water. Salt water can be desalinated to produce fresh water that can be consumed, and saline wastewater that seriously pollutes the environment can also be treated. At present, there are a large number of saline water resources in the world, such as seawater, industrial saline wastewater, etc., which contain high concentrations of calcium, magnesium, sodium and other ions. For saline wastewater, the existing technology usually adopts physical and electrochemical methods, such as separation membranes, electrolysis, etc., but the existing technology has the problems of high energy consumption and high cost. For example, the cost of reverse osmosis membranes in the existing technology for the treatment of saline wastewater is extremely high, and most companies cannot afford it.

[0004] Therefore, it is necessary to develop a simple, low-energy and efficient brine separation method. Summary of the invention

[0005] In view of the technical problems existing in the prior art, the present invention provides a salt water evaporation separation device. The device uses a polypropylene membrane material with water super-spreading performance as an accelerated evaporation interface, utilizes the rapid water transfer characteristics of the material, and combines its high specific surface characteristics to quickly evaporate the water in the salt water through evaporation. The crystallized salt after drying and dehydration is easily detached after precipitation on the surface of the membrane material, thereby realizing the separation of salt and water. The device can realize the treatment of seawater desalination and saline wastewater from chemical plants, and has the characteristics of high efficiency and easy operation.

[0006] The first aspect of the present invention is to provide a salt water evaporation separation device, comprising a feed component, an evaporation separation component, a salt collection component and a condensed water collection component; wherein the evaporation separation component comprises a super-spread polypropylene fiber membrane; wherein the feed component can distribute salt water from the outside on the surface of the super-spread polypropylene fiber membrane in the evaporation separation component; the salt water can be super-spread on the surface of the super-spread polypropylene fiber membrane, and then evaporated to obtain water vapor and precipitated salt respectively; the salt collection component and the condensed water collection component are used to collect the salt and water vapor respectively;

[0007] The super-spread polypropylene fiber membrane contains a polypropylene fiber membrane matrix and an amphiphilic polymer. Taking the mass of the super-spread polypropylene fiber membrane as 100%, the content of the polypropylene fiber membrane matrix in the super-spread polypropylene fiber membrane is 93%-99.99%; the content of the amphiphilic polymer is 0.01%-7%.

[0008] According to the present invention, preferably, the static contact angle between the polypropylene fiber membrane and water can reach 0° within a time not exceeding 1 second.

[0009] The so-called superspreading (superspreading, superdiffusion or superwetting) is a common term in this field. For example, the paper "Superspreading Phenomenon and Nature of Silicon Surfactants" in "Daily Chemicals Science" Issue 8, 2019, and the paper "Research Progress of Superspreading Characteristics of Fluids on Solid Surfaces" in "Chemical Industry Journal" Volume 65 Issue 3 (March 2014) all involve descriptions of superspreading. Generally, it means that a small volume of droplets (less than 2μl, excluding the influence of gravity) can quickly achieve a contact angle of 0° after contacting the surface of an object. For example, the superspreading polypropylene fiber membrane of the present invention reaches a static contact angle of 0 degrees for water in no more than 1 second, preferably in 0.005 seconds-1 second. Compared with traditional superhydrophilic materials (contact angle less than 5°), materials with superspreading properties have better hydrophilicity, can make liquids quickly transfer and flow in the material, and have high throughput, so they have significant advantages in separation, filtration and other fields. The superspreading polypropylene fiber membrane of the present invention refers to a water superspreading polypropylene fiber membrane.

[0010] According to the present invention, the super-spread polypropylene fiber membrane has excellent hydrophilic properties, can quickly transfer water within the fiber membrane surface in a very short time, spread in the fiber membrane, form a large specific surface area, and can evaporate water faster. It is a key component of the brine evaporation and separation device of the present invention. The preferred embodiment of the super-spread polypropylene fiber membrane in the present invention is described in detail below.

[0011] According to the present invention, the super-spread polypropylene fiber membrane comprises a polypropylene fiber membrane matrix and an amphiphilic polymer, and based on the mass of the super-spread polypropylene fiber membrane as 100%, the content of the polypropylene fiber membrane matrix in the super-spread polypropylene fiber membrane is 93%-99.99%; the content of the amphiphilic polymer is 0.01%-7%; the static contact angle of the polypropylene fiber membrane with water can reach 0° within a time not exceeding 1 second. In a preferred embodiment of the present invention, based on the mass of the super-spread polypropylene fiber membrane as 100%, the content of the polypropylene fiber membrane matrix in the super-spread polypropylene fiber membrane is 95%-99.95%, for example, it can be 95%, 97%, 98.3%, 99%, 99.95%, and any two values ​​or any interval between any two values; the content of the amphiphilic polymer is 0.05%-5%, for example, 0.01%, 0.7%, 3%, 5%, and any two values ​​or any interval between any two values.

[0012] Preferably, the sum of the content of the polypropylene fiber membrane matrix and the content of the amphiphilic polymer is 100%.

[0013] According to the present invention, the mass content of the amphiphilic polymer in the super-spread polypropylene fiber membrane can be detected by conventional detection methods in the art, including but not limited to the following methods: take an unmodified polypropylene fiber membrane and weigh its mass m1, treat it by the method listed in the embodiment and then dry it to obtain a treated polypropylene fiber membrane, weigh its mass m2, and the percentage (m2-m1) / m2×100% is the mass content of the amphiphilic polymer.

[0014] According to the present invention, the content of the amphiphilic polymer per unit surface area of ​​the super-spread polypropylene fiber membrane can be selected in a wide range. In a preferred embodiment of the present invention, the content of the amphiphilic polymer per unit surface area of ​​the super-spread polypropylene fiber membrane is 0.005 g / m 2 -3g / m 2 , preferably 0.005g / m 2 -2g / m 2 , for example 0.005g / m 2 , 1g / m 2 , 2g / m 2 , and any two values ​​or any interval between any two values.

[0015] According to the present invention, the content of the amphiphilic polymer per unit surface area of ​​the super-spread polypropylene fiber membrane can be detected by conventional detection methods in the art. Including but not limited to the following methods: first, the sample to be tested is coated with gold on the surface, and then the coated sample is placed on the SEM detection table, and the 5μm×5μm area on the sample is scanned by SEM, and then the mass fraction of oxygen in the polypropylene fiber membrane before modification and the polypropylene fiber membrane after hydrophilic modification is determined by EDS spectrum in this area, which are respectively recorded as w0 and w1, and calculated according to the following formula: W=(w1-w0) / (M O / M A )×M, where M O is the relative atomic mass of oxygen, M A is the molecular weight of a single chain segment of the amphiphilic polymer, M is the surface density of the polypropylene fiber membrane, and W is the content of the amphiphilic polymer per unit area of ​​the super-spread polypropylene fiber membrane.

[0016] According to the present invention, the polypropylene fiber membrane substrate has a wide range of options, and the fiber membrane substrate can be, for example, meltblown polypropylene nonwoven fabric, spunbonded polypropylene nonwoven fabric, or a multilayer composite fabric of meltblown polypropylene nonwoven fabric and spunbonded polypropylene nonwoven fabric.

[0017] According to the present invention, when the fiber diameter of the fiber membrane is within a certain range, capillary force can be generated between the fibers, thereby improving the hydrophilicity of the polypropylene fiber through the self-assembled amphiphilic polymer, so that water can spread at a very fast speed under the action of capillary force. In a preferred embodiment of the present invention, the fiber diameter in the super-spreading polypropylene fiber membrane is less than 20 microns, preferably less than 10 microns, and more preferably 0.1-10 microns.

[0018] The fiber diameter range of the polypropylene fiber membrane substrate in the present invention refers to the nominal fiber diameter range of commercially available polypropylene fiber membrane substrates in the art or the statistical value obtained by detection. As long as the nominal fiber diameter range or the statistical value obtained by detection is within the scope of the present invention, the situation that the diameter range of some (or several) fibers on the overall polypropylene fiber membrane substrate is not within the scope of the present invention also belongs to the protection scope of the present invention.

[0019] The above fiber diameter detection method can adopt conventional detection in the art, including but not limited to observing the fiber with a microscope, such as an electron microscope, an optical microscope, and measuring and statistically analyzing the fiber diameter.

[0020] According to the present invention, only amphiphilic and water-soluble polymers can achieve capillary self-assembly. In a preferred embodiment of the present invention, the amphiphilic polymer is selected from polyvinyl alcohol. The present invention achieves the coating of the amphiphilic polymer on the surface of the polypropylene fiber through capillary self-assembly, thereby achieving super-hydrophilic and super-spreading effects. Experimental verification shows that non-amphiphilic polymers cannot improve the polypropylene fiber membrane.

[0021] According to the present invention, the water-soluble amphiphilic copolymer refers to a polymer containing both a hydrophilic segment and a lipophilic segment in the molecular chain, and such a polymer has a certain affinity for two phases (usually a water phase and an oil phase) with different properties. Preferably, the amphiphilic polymer is polyvinyl alcohol and / or a cross-linked polymer formed by polyvinyl alcohol and a cross-linking agent; more preferably, it is a cross-linked polymer formed by polyvinyl alcohol and a cross-linking agent.

[0022] According to the present invention, in order to ensure long-term and efficient operation of the separation device, the amphiphilic polymer is preferably subjected to a cross-linking reaction, and the selectable range of the cross-linking agent is relatively wide. In a preferred embodiment of the present invention, the cross-linking agent is selected from at least one of a polyacid and a polyaldehyde, including but not limited to at least one of glutaraldehyde and boric acid.

[0023] According to the present invention, the cross-linking agent is preferably selected from at least one of a polyacid and a polyaldehyde, more preferably glutaraldehyde and / or boric acid.

[0024] According to the present invention, the super-spread polypropylene fiber membrane is a super-hydrophilic polypropylene fiber membrane without a layered structure.

[0025] The layered structure refers to the layering of the modified fiber membrane (or fiber cloth). Taking the fiber membrane modified with an amphiphilic polymer as an example, the fiber membrane modified with an amphiphilic polymer having a layered structure is a layer of amphiphilic polymer formed on the surface of the fiber membrane matrix, that is, the amphiphilic polymer layer, and the fiber membrane matrix is ​​lined on one side of the amphiphilic polymer layer. The prior art mainly has a modified fiber membrane with a layered structure, which will form a functional material layer (such as a polymer layer or an inorganic layer) on one side or both sides of the membrane matrix. This type of functional material layer is a layered structure that is relatively independent of the membrane matrix on a macroscopic level. The weight and thickness of a small amount of functional material that penetrates into the membrane matrix are negligible compared to the functional material in the functional material layer, which is different from the polymer without a layered structure in the present invention.

[0026] The super-spread polypropylene fiber membrane of the present invention is a super-hydrophilic polypropylene fiber membrane without a layered structure. The amphiphilic polymer in the present invention does not have the above-mentioned layering. Instead, the amphiphilic polymer is wrapped around the outside of each fiber of the polypropylene fiber membrane.

[0027] According to the present invention, preferably, the amphiphilic polymer can self-assemble on the fiber surface in the polypropylene fiber membrane matrix, the lipophilic segments in the amphiphilic polymer are assembled on the polypropylene fiber surface, and the hydrophilic segments are distributed on the fiber surface after assembly, thereby improving the hydrophilicity of the polypropylene fiber membrane. Preferably, the super-spread polypropylene fiber membrane contains polypropylene fibers coated with amphiphilic polymers, which are observed under a transmission electron microscope after staining with metal ruthenium.

[0028] In a preferred embodiment of the present invention, the super-spread polypropylene fiber membrane contains polypropylene fibers coated with amphiphilic polymers. Preferably, the amphiphilic polymers are coated on the polypropylene fibers by capillary self-assembly. That is, self-assembly is achieved under the action of capillary force, the lipophilic segments in the amphiphilic polymers are attached to the surface of the polypropylene fibers, and the hydrophilic segments are exposed to the outside, thereby forming a fiber surface with a hydrophilic structure. In application, the capillary structure of the fiber membrane itself is well preserved, and coupled with the effect of the amphiphilic polymers, a hydrophilic / super-spreading effect is achieved under the action of capillary force. The amphiphilic polymers on the super-spread polypropylene fiber membrane of the present invention are different from the amphiphilic polymers cast or coated on the fiber membrane surface. The hydrophilicity distribution of the amphiphilic polymers of the present invention is more uniform, and the super-spread polypropylene fiber membrane of the present invention does not have an obvious layered structure.

[0029] In a preferred embodiment of the present invention, the method for preparing the super spread polypropylene fiber membrane comprises:

[0030] The method comprises contacting a polypropylene fiber membrane substrate with a solution containing an amphiphilic polymer under the action of an external force, wherein the content of the amphiphilic polymer in the solution is not higher than 5wt%, and optionally subjecting the polypropylene fiber membrane obtained after the polypropylene fiber membrane substrate is contacted with the amphiphilic polymer to a cross-linking reaction in a solution containing a cross-linking agent to obtain the super-spread polypropylene fiber membrane.

[0031] As described above, the amphiphilic polymer realizes self-assembly under the action of capillary force, the lipophilic segments in the amphiphilic polymer are attached to the surface of the polypropylene fiber, and the hydrophilic segments are exposed to the outside, thereby forming a fiber surface with a hydrophilic structure (i.e., the amphiphilic polymer is wrapped on the fiber surface), and the hydrophilic / super-spreading effect is achieved under the action of capillary force. The amphiphilic polymer in the present invention is more evenly distributed and has a non-layered structure.

[0032] Preferably, the contacting is performed in a solution containing an amphiphilic polymer.

[0033] The contact utilizes intermolecular forces to cause the amphiphilic polymer to self-assemble on the surface of the polypropylene fiber membrane fiber, thereby obtaining a polypropylene fiber membrane coated with the amphiphilic polymer. That is, the water-soluble amphiphilic polymer (hydrophilic, lipophilic, and soluble in water) used in the present invention can disperse the water-soluble polymer molecular chain and load it on the surface of the polypropylene fiber by a self-assembly method, thereby forming a fiber membrane with a super-hydrophilic effect. The super-spreading polypropylene fiber membrane realizes the hydrophilic modification of the polypropylene fiber membrane by the amphiphilic polymer by a capillary force self-assembly method.

[0034] The present invention has found through experiments that, after induction by external force, a water-soluble polymer having a hydrophilic segment and a lipophilic segment can be assembled with a polypropylene fiber membrane through a self-assembly method. Since polypropylene is a lipophilic polymer, the lipophilic segment in the water-soluble polymer is assembled on the fiber surface in the polypropylene fiber membrane. The interaction force between the hydrophilic segment and the polypropylene fiber is weak, and the hydrophilic segment cannot be assembled on the fiber surface, thereby being exposed to the outside. Therefore, the polypropylene fiber has hydrophilic properties, and the polypropylene fiber membrane also has hydrophilic and lipophilic properties, and the spreading time is fast. At the same time, the fiber diameter of the polypropylene fiber membrane in the present invention is preferably less than 20 microns, preferably less than 10 microns, and more preferably 0.1-10 microns. A strong capillary action can occur, and water can be quickly transferred along the fiber under the action of capillary force, so that the polypropylene fiber membrane has excellent spreading performance. The maximum size of a droplet with a volume of 2 μL is not less than 7 mm in the spreading area after the fiber membrane is spread, the maximum size of a droplet with a volume of 5 μL is not less than 8 mm in the spreading area after the fiber membrane is spread, the maximum size of a droplet with a volume of 8 μL is not less than 12 mm in the spreading area after the fiber membrane is spread, and the maximum size of a droplet with a volume of 12 μL is not less than 15 mm in the spreading area after the fiber membrane is spread.

[0035] In a preferred embodiment of the present invention, the content of the amphiphilic polymer in the solution containing the amphiphilic polymer is 0.05-4.5wt%, preferably 0.1-4.5wt%. Under the above-mentioned amphiphilic polymer concentration conditions and the action of external force, the contact utilizes intermolecular forces to cause the amphiphilic polymer to self-assemble on the surface of the polypropylene fiber membrane to obtain a polypropylene fiber membrane coated with the amphiphilic polymer.

[0036] As described above, the content of the amphiphilic polymer in the solution containing the amphiphilic polymer is 0.05-4.5wt%, preferably 0.1-4.5wt%, for example 0.1wt%, 0.5wt%, 1wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 4.5wt%, and any two values ​​or any range between any two values, more preferably 0.3-3wt%.

[0037] In a more preferred embodiment of the present invention, the contacting is carried out in a solution containing an amphiphilic polymer, so that the super-spreading performance of the obtained polypropylene fiber membrane is more uniform.

[0038] According to the present invention, the contact between the fiber membrane and the amphiphilic polymer can be carried out in a wide temperature range, preferably not exceeding the melting temperature of polypropylene and the amphiphilic polymer, and more preferably not exceeding the glass transition temperature of the amphiphilic polymer.

[0039] In a preferred embodiment of the present invention, the preparation method further includes a drying step after the polypropylene fiber membrane substrate is contacted with the amphiphilic polymer; preferably, the contact temperature and the drying temperature each do not exceed the melting temperature of the fiber membrane substrate and the amphiphilic polymer, and more preferably do not exceed the glass transition temperature of the amphiphilic polymer.

[0040] According to the present invention, preferably, the contact is carried out under the action of an external force; during the self-assembly process of the amphiphilic polymer on the surface of the polypropylene fiber, an external force can be used to induce its rapid assembly, and the external force is not limited to one or more of ultrasound, rolling, filtration, lamination, molding and the like.

[0041] According to the present invention, the range of conditions under which the external force acts is relatively wide, such as the treatment time, the number of treatments and the process conditions of the treatment method, and there is no specific limitation.

[0042] Preferably, the external force comprises a combination of one or more of ultrasound, rolling, filtration, lamination, and molding; more preferably,

[0043] The ultrasonic conditions include: the ultrasonic frequency is not less than 5kHz, preferably not less than 10kHz, such as 10kHz, 20kHz, 30kHz, 40kHz, 45kHz, 50kHz, 55kHz, 60kHz. The greater the ultrasonic power, the less the action time and the number of actions.

[0044] According to the present invention, the ultrasonic treatment equipment can be selected from conventional ultrasonic treatment equipment including but not limited to ultrasonic cleaning table, cell crusher, ultrasonic probe, industrial ultrasonic device, etc. The power of the specific ultrasonic treatment equipment is not particularly limited by the present invention. Preferably, the power is 50-750W, preferably 50-500W, and more preferably 150-350W.

[0045] According to the present invention, the selectable range of the time for ultrasonic treatment in the preparation step is relatively wide, and the ultrasonic time is related to the solution concentration, fiber diameter, and surface density. According to the process conditions of the embodiments of the present invention, preferably, the ultrasonic time is not less than 1 minute, preferably not less than 5 minutes, and more preferably 10-120 minutes, for example, it can be 10 minutes, 20 minutes, 30 minutes, 40 minutes, 60 minutes, 100 minutes, 120 minutes, and the like.

[0046] In another preferred specific embodiment of the present invention, the conditions for suction filtration can be selected in a wide range, and as the vacuum degree increases, the processing time and the number of processing times can be reduced. In a preferred embodiment of the present invention, the conditions for suction filtration include: the vacuum degree is not less than 5Pa, preferably not less than 10Pa, and / or the suction filtration time is not shorter than 1 second, preferably not less than 5 seconds. Preferably, the infiltration state of the polypropylene fiber membrane substrate by the amphiphilic polymer solution is still maintained before stopping the suction filtration.

[0047] In another preferred specific embodiment of the present invention, the conditions for rolling include: the pressure is not less than 5 Pa, preferably not less than 10 Pa; and the number of rolling times is not less than 1 time.

[0048] In a more preferred embodiment of the present invention, the preparation method may include the following steps:

[0049] The polypropylene fiber membrane substrate is placed in a solution containing an amphiphilic polymer and brought into contact with the solution containing an amphiphilic polymer under the action of an external force; the aqueous solution of the amphiphilic polymer is immersed in the polypropylene fiber membrane substrate; and the process is dried.

[0050] As described above, in a preferred embodiment of the present invention, the amphiphilic polymer is selected from polyvinyl alcohol. That is, self-assembly is achieved under the action of capillary force, the lipophilic segments in the amphiphilic polymer are attached to the surface of the polypropylene fiber, and the hydrophilic segments are exposed to the outside, thereby forming a fiber surface with a hydrophilic structure. In application, the capillary structure of the fiber membrane itself is well retained, and coupled with the effect of the amphiphilic polymer, the hydrophilic / super-spreading effect is achieved under the action of capillary force.

[0051] The amphiphilic polymer on the super-spread polypropylene fiber membrane of the present invention is different from the amphiphilic polymer cast or coated on the fiber membrane surface. The hydrophilicity distribution of the amphiphilic polymer of the present invention is more uniform, and the super-spread polypropylene fiber membrane of the present invention does not have an obvious layered structure. In addition, the amphiphilic polymer of the present invention is wrapped on the surface of the fiber, rather than cast or coated on one side of the fiber membrane. In this way, the capillaries between the fibers of the fiber membrane of the present invention are well retained. In addition, the effect of the amphiphilic polymer enables water to achieve a hydrophilic / super-spreading effect under the action of capillary force in the application.

[0052] According to the present invention, there is no particular limitation on the molecular weight of the amphiphilic polymer, for example, the number average molecular weight may be 30000-300000. Taking the embodiments of the present invention as an example, polyvinyl alcohol with a degree of polymerization of 1700 may be selected.

[0053] According to the present invention, the polypropylene fiber film substrate has a wide range of options, for example, it can be meltblown polypropylene non-woven fabric, spunbond polypropylene non-woven fabric, meltblown and spunbond polypropylene composite non-woven fabric, spunlace polypropylene non-woven fabric, etc. According to the present invention, meltblown polypropylene non-woven fabric and meltblown and spunbond polypropylene composite non-woven fabric are preferred.

[0054] According to the present invention, preferably, the surface density of the polypropylene fiber membrane substrate is 10-60 g / m 2 , preferably 20-50g / m 2 , and / or, the fiber diameter is not greater than 20 microns, preferably less than 10 microns, more preferably 0.1-10 microns. In this preferred embodiment, the fiber diameter of the fiber membrane generates capillary force between the fibers, thereby improving the hydrophilicity of the polypropylene fiber through the self-assembled amphiphilic polymer, and after encountering water, the water can spread at a very fast speed under the action of capillary force.

[0055] The fiber diameter range of the polypropylene fiber membrane substrate in the present invention refers to the nominal fiber diameter range of the commercially available polypropylene fiber membrane substrate in the art or the statistical value obtained by detection. As long as the nominal fiber diameter range or the statistical value obtained by detection is within the scope of the present invention, the situation that the diameter range of some (or several) fibers on the overall polypropylene fiber membrane substrate is not within the scope of the present invention also belongs to the protection scope of the present invention. The above fiber diameter detection method can adopt conventional detection in the art, including but not limited to observing the fiber with a microscope, such as an electron microscope, an optical microscope, and measuring and statistically analyzing the fiber diameter.

[0056] The preparation method further comprises an optional cross-linking step, which can be performed optionally according to specific uses, and preferably comprises a cross-linking step.

[0057] When the cross-linking step is included, the polypropylene fiber membrane obtained by contacting the polypropylene fiber membrane substrate with the amphiphilic polymer is subjected to cross-linking reaction in a solution containing a cross-linking agent.

[0058] The cross-linked amphiphilic polymer forms a cross-linked structure, and the stability of the amphiphilic polymer in the fiber membrane is increased, thereby improving the hydrophilic stability.

[0059] The super-spreading performance stability refers to the degree of change in contact angle after the hydrophilic fiber membrane is completely immersed in deionized water and treated under ultrasonic cleaning conditions for 5 minutes, repeated 3 times. The smaller the change in contact angle, the better its hydrophilic stability.

[0060] According to the present invention, the cross-linking agent has a wide selection range. In a preferred embodiment of the present invention, the cross-linking agent is selected from at least one of a polyacid and a polyaldehyde, preferably at least one of glutaraldehyde and boric acid, more preferably glutaraldehyde; and / or,

[0061] The content of the crosslinking agent in the solution containing the crosslinking agent is 0.005-0.8 wt %, preferably 0.01-0.5 wt %; and / or, the temperature conditions for crosslinking include:

[0062] The cross-linking temperature does not exceed the glass transition temperature of the amphiphilic polymer, preferably 30-70°C; and / or the pH of the solution containing the cross-linking agent is 4-7; the cross-linking reaction time is 1 min-120 min, preferably 1 min-90 min, for example, it can be 1 min, 3 min, 5 min, 10 min, 20 min, 50 min, 70 min, 90 min, and any two values ​​or any interval between any two values.

[0063] The present invention has no particular limitation on the raw materials for adjusting pH, and any conventional acid or alkali raw materials in the art may be used.

[0064] According to the present invention, the fiber membrane that has been cross-linked can be cleaned to remove residual cross-linking agents and other substances. The present invention has no particular restrictions on the cleaning method, including but not limited to rinsing with water. In order to improve the efficiency of cleaning, it is preferably cleaned under ultrasonic conditions. The ultrasonic conditions here are not particularly limited by the present invention. For example, the frequency of ultrasound is 20-80kHz. Preferably, the ultrasonic cleaning time is 1-30 minutes / time, preferably 15-25 minutes / time, and the number of cleaning times is selected from 1-5 times, preferably 2-4 times.

[0065] According to the present invention, if the super-spread polypropylene fiber membrane needs to be dried, the drying temperature is not higher than the glass transition temperature of the amphiphilic polymer. When the treatment temperature is higher than the glass transition temperature, the amphiphilic polymer undergoes molecular segment movement, which will destroy the structure formed by its self-assembly and affect the super-spreading performance.

[0066] The present invention described above is a super-spread polypropylene fiber membrane and a preferred preparation scheme of the present invention.

[0067] In a preferred embodiment of the present invention, the super spread polypropylene fiber membrane has at least one of the following characteristics:

[0068] After a droplet with a volume of 2 μL is spread on the super-spread polypropylene fiber membrane, the maximum size of the spreading area is not less than 7 mm, after a droplet with a volume of 5 μL is spread on the super-spread polypropylene fiber membrane, the maximum size of the spreading area is not less than 8 mm, after a droplet with a volume of 8 μL is spread on the super-spread polypropylene fiber membrane, the maximum size of the spreading area is not less than 12 mm, and after a droplet with a volume of 12 μL is spread on the super-spread polypropylene fiber membrane, the maximum size of the spreading area is not less than 15 mm.

[0069] The method for detecting the maximum size of the droplet spreading area on the fiber membrane can be detected by conventional detection methods in the art. Including but not limited to the following methods: stick the fiber membrane sample flat on a glass slide, and pay attention to keep the sample flat in the horizontal direction during the pasting process, then place the glass slide on the sample stage of the contact angle meter and fix it, and control the volume of the droplet by adjusting the instrument, and the volume can be 2μL, 5μL, 8μL, 12μL. Drop a drop of water on the center of the sample, remove the glass slide after the contact angle becomes 0 degrees, and measure the size of the spreading area. The shape of the spreading area is approximately circular, and its diameter or diagonal can be taken as the maximum size.

[0070] According to the present invention, the super-spreading polypropylene fiber membrane can reach a static contact angle of 0 degrees with water within 1 second, and more preferably, can reach a static contact angle of 0 degrees with water within 0.005 seconds to 1 second. For example, it can be 0.005 seconds, 0.01 seconds, 0.05 seconds, 0.1 seconds, 0.5 seconds, 0.9 seconds, 1 second, and any two values ​​or any interval between any two values.

[0071] According to the present invention, the test of the time required for the static contact angle of the polypropylene fiber membrane to reach 0 degrees with water can be detected by conventional detection methods in the art. Including but not limited to the following methods: the fiber membrane sample is flat on a glass slide, and it is important to keep the sample flat in the horizontal direction during the pasting process, and then the glass slide is placed on the sample stage of the contact angle measuring instrument and fixed, and the instrument is adjusted to control the volume of water droplets below 2μL to the center of the sample, and the angle from the solid-liquid interface through the inside of the droplet to the vapor-liquid interface at the junction of the three phases is measured, which is the static contact angle (referred to as water contact angle). The time calculation starts from the droplet contacting the fiber membrane surface and adjusting the lift to leave the droplet, until the droplet is completely spread and the contact angle reaches 0 degrees. The volume is controlled to be below 2μL in order to eliminate the influence of gravity, and better illustrate that the polypropylene fiber membrane has good hydrophilicity and super spreading performance.

[0072] According to the present invention, preferably, the weight of the super spread polypropylene fiber membrane per square meter is 9-100 g / square meter, preferably 10-50 g / square meter.

[0073] According to the present invention, preferably, the super spread polypropylene fiber membrane, that is, the accelerated evaporation membrane, has a high specific surface area. Preferably, the specific surface area of ​​the super spread polypropylene fiber membrane is greater than 0.3 m2 / g, preferably greater than 0.7 m2 / g.

[0074] According to the experiment, under the same conditions, the accelerated evaporation membrane with a large specific surface area has a faster water evaporation rate. At the same time, it was also found in the experiment that the spreading speed of water in the accelerated evaporation membrane has a significant effect on the water evaporation degree. The faster spreading speed can make the water flow quickly in the accelerated evaporation membrane, reducing the evaporation rate caused by uneven water distribution. According to the experimental results, the water evaporation rate is not less than 3000ml / hm 2 , preferably the water evaporation rate is not less than 4000ml / / hm 2 , more preferably the water evaporation rate is not less than 4500ml / / hm 2 . The fiber diameter of fiber membranes such as spunbond nonwoven fabrics is relatively large, and the specific surface area formed is relatively small, while the fiber diameter of fiber membranes such as meltblown fabrics is relatively small, and the specific surface area formed is relatively large. Therefore, the weight per square meter of the super-spread polypropylene fiber membrane is 9-100 g / m2, preferably 10-60 g / m2; the fiber diameter in the fiber membrane is not greater than 20 microns, preferably less than 10 microns, and more preferably 0.1-10 microns. The fiber diameter is the average diameter of the fibers in the fiber membrane.

[0075] According to the present invention, preferably, the static contact angle of water of the super-spreading polypropylene fiber membrane reaches 0 degrees within 0.005 seconds to 1 second.

[0076] In the present invention, the super-spread polypropylene fiber membrane can be used alone as an accelerated evaporation membrane. In order to further enhance the mechanical properties, it can also be reinforced with a multi-layer hydrophilic membrane, and can also be fixed with a mesh material of other materials.

[0077] According to the present invention, the super-spread polypropylene fiber membrane is a key component of the salt water evaporation separation device of the present invention. The above invention describes in detail the preferred scheme and preferred preparation scheme of the super-spread polypropylene fiber membrane of the present invention.

[0078] According to the present invention, the brine evaporation and separation device comprises a feed component, an evaporation and separation component, a salt collection component and a condensed water collection component; wherein the evaporation and separation component comprises a super-spread polypropylene fiber membrane; the super-spread polypropylene fiber membrane is a super-hydrophilic polypropylene fiber membrane without a layered structure; wherein the feed component can distribute brine from the outside on the surface of the super-spread polypropylene fiber membrane in the evaporation and separation component; the brine can be super-spread on the surface of the super-spread polypropylene fiber membrane, and then evaporated to obtain water vapor and precipitated salt respectively; the salt collection component and the condensed water collection component are used to collect the salt and water vapor respectively.

[0079] In the present invention, the feed assembly and the evaporation separation assembly can be arranged in a variety of ways. For example, the liquid outlet end of the feed assembly can move relative to the super-spread polypropylene fiber membrane in the evaporation separation assembly, or can remain stationary. There are also a variety of movement modes. As long as the feed assembly can distribute the salt water from the outside on the surface of the super-spread polypropylene fiber membrane in the evaporation separation assembly, the rapid evaporation of the water in the salt water can be achieved, thereby achieving the purpose of the invention.

[0080] In order to improve working efficiency, preferably, the liquid outlet end of the feed assembly and the super-spread polypropylene fiber membrane can move relative to each other to distribute the brine transported by the liquid outlet end of the feed assembly on the upper surface of the super-spread polypropylene fiber membrane.

[0081] In a preferred embodiment of the present invention, the liquid outlet end of the feed assembly is fixed, and the super-spread polypropylene fiber membrane can move in a horizontal direction or can intermittently flip around an axis in a horizontal plane. Preferably, the super-spread polypropylene fiber membrane can move in a circular motion in a horizontal direction.

[0082] In another preferred embodiment of the present invention, the liquid outlet end of the feed assembly can move in the horizontal direction, and the super-spread polypropylene fiber membrane is stationary or intermittently flips around an axis in the horizontal plane or can move in a circular motion in the horizontal direction.

[0083] According to the present invention, the liquid outlet end of the feed component can be a conventional liquid outlet component in the art, including but not limited to a water pipe and / or a nozzle. The salt that may be contained in the brine includes inorganic salts such as sodium chloride, sodium sulfate, potassium chloride, sodium phenolate, potassium sulfate, magnesium chloride, and calcium chloride, and the mass fraction is usually 0.1%-25%. In order to avoid corrosion of the component, the feed component can be made of corrosion-resistant materials or treated with an anti-corrosion coating, and the treatment method adopts the existing technology.

[0084] According to the present invention, regardless of whether the liquid outlet end of the feed assembly moves, preferably, the super-spread polypropylene fiber membrane can move in a circular motion in the horizontal direction. More preferably, the evaporation separation assembly comprises a super-spread polypropylene fiber membrane and a transmission module capable of transmitting the super-spread polypropylene fiber membrane to move in a circular motion in the horizontal direction, preferably, the transmission module comprises an annular conveyor belt, and more preferably, the annular conveyor belt has a mesh structure.

[0085] According to the present invention, the evaporation separation component includes an accelerated evaporation membrane, namely the super-spread polypropylene fiber membrane, and a transmission module. In order to accelerate the evaporation rate, a blowing module can also be added to increase the internal air flow.

[0086] The transmission module described in the present invention is a device in the prior art that can be used for the operation of the super-spread fiber membrane. The transmission module preferably used is a conveyor belt transmission module, which fixes the super-spread polypropylene fiber membrane on the crawler belt and drives the conveyor belt to rotate cyclically through a motor. The conveyor belt is preferably a mesh conveyor belt, which can increase the contact between the fiber membrane and the air and increase the evaporation rate. The conveyor belt material can be any material in the prior art, preferably stainless steel or synthetic resin material with corrosion resistance. There is no restriction on the hydrophilicity of the conveyor belt.

[0087] According to the present invention, in order to improve the evaporation efficiency, preferably, the evaporation separation component further includes an air blowing module, for example, which can be fed with dry compressed air.

[0088] The evaporation efficiency of the evaporation separation component can be accelerated at a certain temperature, but too high a temperature will result in greater energy consumption. The existing low-grade heat sources in chemical plants are widely distributed and difficult to recover, and are suitable for use as supplementary heat sources in the present invention, with a temperature range of below 100°C. To further speed up the process, the brine can also be preheated, and the preheating temperature is related to the heat provided by the low-grade heat source and can be any temperature not higher than 100°C. Preferably, the ambient temperature during evaporation separation is 40°C-80°C. More preferably, the brine evaporation separation device further includes a heating component, and the heat source of the heating component is preferably from an external recovery heat source (e.g., waste liquid with a heat source).

[0089] According to the present invention, the evaporative separation component comprises a reinforcing material disposed below the super-spread polypropylene fiber membrane; preferably, the reinforcing material is at least one of a hydrophilic membrane, a hydrophilic and / or non-hydrophilic mesh material.

[0090] According to the present invention, preferably, the salt water evaporation separation device comprises a shell, an evaporation separation component arranged in the inner cavity of the shell, a feed component and a condensed water collection component arranged on the shell and connected to the inner cavity of the shell.

[0091] The condensate collection assembly described in the present invention can condense steam using any condensation method in the prior art.

[0092] According to the present invention, preferably, the salt collection component is arranged below the evaporation separation component, or, is arranged below the shell and is connected to the inner cavity of the shell through a closable discharge port. Preferably, the salt collection component of the present invention is a corrosion-resistant container that can separate the salt obtained by the evaporation separation component. Such as sodium chloride, sodium sulfate, potassium chloride, sodium phenolate, potassium sulfate, magnesium chloride, calcium chloride and other inorganic substances.

[0093] For ease of understanding, a preferred embodiment of the salt water evaporation separation device of the present invention is described below in conjunction with the accompanying drawings. Figure 1 As shown, the salt water evaporation and separation device includes a feed component 1, an evaporation and separation component, a condensed water collection component 3, and a salt collection component 5, wherein the evaporation and separation component includes a super-spread polypropylene fiber membrane 2 and a transmission module 4; the transmission module 4 drives the super-spread polypropylene fiber membrane 2 to move in a circular motion in the horizontal direction, and during the motion, the feed component 1 distributes the salt water on the super-spread polypropylene fiber membrane 2, and the salt water is super-spread on the surface of the super-spread polypropylene fiber membrane 2, and water vapor and salt precipitated from the super-spread polypropylene fiber membrane 2 are obtained by evaporation, and the water vapor is collected in the condensed water collection component 3; when the salt moves to the bottom of the ring with the super-spread polypropylene fiber membrane 2, under the action of gravity or external force (for example, setting a scraper), the salt falls from the super-spread polypropylene fiber membrane 2 to the salt collection component 5.

[0094] Preferably, a liquid outlet is further provided at the lower part of the salt water evaporation separation device, and preferably, the liquid outlet is connected to the feed assembly 1, so as to collect the unevaporated liquid, and preferably return it to the feed assembly for re-feeding.

[0095] The second aspect of the present invention is to provide a method for performing brine evaporation separation using the brine evaporation separation device described in the first aspect, comprising the following steps:

[0096] (1) distributing the brine on the super-spread polypropylene fiber membrane of the evaporation separation component through a feed component;

[0097] (2) the salt water is super-spread on the surface of the super-spread polypropylene fiber membrane, and water vapor and salt precipitated from the super-spread polypropylene fiber membrane are obtained by evaporation;

[0098] (3) The water vapor is collected by a condensed water collection component to obtain condensed water; and the precipitated salt is collected by a salt collection component to obtain salt.

[0099] Preferably, the brine distributed on the super-spread polypropylene fiber membrane is super-spread on the surface of the super-spread polypropylene fiber membrane in the form of droplets.

[0100] According to the present invention, the speed of brine feeding can be flexibly adjusted. For example, when the amount of brine fed is much higher than the evaporation rate, part of the brine that has not had time to evaporate can be collected at the lower part of the brine evaporation and separation device, that is, the lower part of the shell. Preferably, the unevaporated brine is collected at the lower part of the brine evaporation and separation device, and preferably returned to the feed assembly through the liquid outlet.

[0101] According to the present invention, the brine has a mass concentration of 0.1%-25%, and the salts therein include but are not limited to sodium chloride, sodium sulfate, potassium chloride, sodium phenolate, potassium sulfate, magnesium chloride, calcium chloride and the like.

[0102] During the separation process, in order to increase the separation efficiency, the brine can be preheated, and the temperature in the evaporation separation component can be raised to 40-80° C., preferably to 50-80° C. Similarly, in order to speed up the evaporation rate, compressed air can be introduced into the evaporation separation component, and the amount of compressed air introduced is unlimited. As the amount of compressed air introduced increases, the drying rate increases.

[0103] In a preferred embodiment of the present invention, the steps adopted in the brine separation method include the following:

[0104] (1) adding brine into the evaporation separation component through the feed component;

[0105] (2) The brine entering the evaporation separation component is quickly spread on the super-spread polypropylene fiber membrane, and the transmission module drives the super-spread polypropylene fiber membrane to move, further increasing the spreading area;

[0106] (3) The water after spreading begins to evaporate, and salt crystals are continuously precipitated as the water evaporates; when the amount of salt precipitation reaches a certain level, it begins to fall off and enter the salt collection component due to gravity under the horizontal circular motion of the super-spread polypropylene fiber membrane;

[0107] (4) The evaporated water vapor enters the condensed water collection component to complete the brine separation;

[0108] The excess unevaporated brine is collected below and returned to the feed assembly.

[0109] The third aspect of the present invention is to provide an application of the brine evaporation separation device described in the first aspect or the method described in the second aspect in the field of seawater desalination and concentrated brine treatment in chemical plants.

[0110] The accelerated evaporation brine desalination equipment of the present invention can be applied to brine desalination, and the brine includes but is not limited to seawater, concentrated brine produced by membrane separation, concentrated brine produced by mechanical evaporation and recompression, and saline wastewater from chemical plants.

[0111] Compared with the prior art, the present invention has the following advantages:

[0112] The brine separation device of the present invention utilizes the excellent spreading performance and large specific surface area of ​​the super-spread fiber membrane. When the brine is spread in the fiber membrane, rapid evaporation of water can be achieved. When the salt reaches saturation concentration, crystals are precipitated and easily collected, thereby achieving efficient brine separation.

[0113] The super-spread fiber membrane in the present invention uses polypropylene with good corrosion resistance as a matrix, which can meet different salt water separation application scenarios. In addition, the device has the characteristics of simple operation and low energy consumption, and is easy to promote and implement.

[0114] The polypropylene fiber membrane of the present invention has the above properties because the inventors unexpectedly discovered through their research that when the fiber diameter of the polypropylene fiber membrane is less than a certain size, capillary phenomena occur on the surface and inside of the fiber membrane, and the solution contacts the surface of the polypropylene fiber through the action of capillary force or with the help of external force during the contact or impregnation process with the aqueous solution of the amphiphilic polymer. When the content of the amphiphilic polymer in the solution of the amphiphilic polymer is not higher than 5wt%, the molecular chains of the amphiphilic polymer in the aqueous solution are uniformly dispersed, and the lipophilic segments (segments without hydroxyl groups) thereof show good compatibility with the equally lipophilic polypropylene, and self-assemble and combine after contacting with the polypropylene fiber membrane matrix. In this process, the amphiphilic polymer arranges the hydrophilic segments and the lipophilic segments separately, that is, the lipophilic segments are coated on the surface of the polypropylene fiber, and the hydrophilic segments are exposed on the surface of the polypropylene fiber after self-assembly, thereby making the polypropylene fiber membrane have hydrophilic properties. By controlling the process conditions (such as external force, concentration of the amphiphilic polymer, etc.), the thin layer self-assembly of the amphiphilic polymer on the surface of the polypropylene fiber can be achieved. Through the combined action of capillary force and self-assembly, the polypropylene fiber membrane contains polypropylene fibers coated with amphiphilic polymers, and optionally through cross-linking, the polypropylene fiber membrane has super-spreading properties. This process can be better achieved under the action of external forces, such as ultrasound, where the amphiphilic polymer solution can quickly enter between the fiber membrane fibers, promoting the contact between the lipophilic segments and the surface of the polypropylene fibers, thereby accelerating the speed and efficiency of self-assembly.

[0115] The prior art generally uses high-cost materials such as fluorine-containing materials, or has complex process implementation. The polypropylene fiber membrane used in the present invention has the characteristics of low cost and corrosion resistance, and has the advantage of being easier to industrialize than high-cost separation equipment such as easily corroded metals in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0116] Figure 1 It is a structural schematic diagram of one preferred embodiment of the brine separation device in the present invention.

[0117] 1. Feeding assembly; 2. Super-spread polypropylene fiber membrane; 3. Condensate collection assembly; 4. Transmission module; 5. Salt collection assembly.

[0118] Figure 2 It is a schematic diagram of the brine separation process. DETAILED DESCRIPTION

[0119] The present invention is described in detail below in conjunction with specific embodiments. It is necessary to point out that the following embodiments are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made to the present invention by those skilled in the art based on the contents of the present invention still fall within the scope of protection of the present invention.

[0120] The experimental data in the examples were measured using the following instruments and measurement methods:

[0121] The water contact angle and spreading time (spreading time is the time required for the water contact angle to reach 0°) obtained in the embodiment are measured using the German EASYDROP contact angle tester: the fiber membrane is cut into samples of 1 cm×1 cm in size, and then the sample is flatly attached to a glass slide. During the pasting process, care should be taken to keep the sample flat in the horizontal direction. The glass slide is then placed and fixed on the sample stage of the EASYDROP contact angle meter. The instrument is adjusted to control the volume to 2 μL and a water droplet is dropped into the center of the sample. After 10 seconds, the angle at the three-phase junction from the solid-liquid interface through the inside of the droplet to the vapor-liquid interface is measured, which is the static contact angle (referred to as the water contact angle).

[0122] Water spreading area test method: Cut the fiber membrane into samples of 3cm×3cm in size, and place the samples flat on a flat glass. Then use a Masterflex 78018-10 peristaltic pump to pump deionized water drops of different volumes to the fiber membrane surface. After the water is completely spread, measure the maximum size at both ends of the spreading area as the spreading size.

[0123] Liquid content of hydrophilic polypropylene fiber membrane: Take a dry hydrophilic polypropylene fiber membrane and weigh it. Then rinse the sample with deionized water until there is no foam, hang it under the conditions of 25℃ and 30% humidity, and weigh it again after no water drops for 1 minute. The difference between the two weighings divided by the mass after drying is the liquid content of the sample, expressed in times.

[0124] The mass content of the amphiphilic polymer in the polypropylene fiber membrane obtained in the example: take an unmodified polypropylene non-woven fabric and weigh its mass m1. Treat it by the method listed in the example and then dry it to obtain a treated polypropylene fiber membrane, and weigh its mass m2. (m2-m1) / m2×100% is the mass content of the amphiphilic polymer.

[0125] The content of the amphiphilic polymer per unit surface area of ​​the polypropylene fiber membrane is as follows: first, the sample to be tested is coated with gold on the surface, and then the coated sample is placed on the SEM detection table, and a 5 μm×5 μm area on the sample is scanned by SEM, and then the mass fraction of oxygen in the polypropylene non-woven fabric before modification and the polypropylene fiber membrane after hydrophilic modification is determined by EDS energy spectrum in the area, which are respectively denoted as w0 and w1, and calculated according to the following formula: W=(w1-w0) / (M O / M A )×M, where M O is the relative atomic mass of oxygen, M A is the molecular weight of a single chain segment of the amphiphilic polymer, M is the surface density of the polypropylene non-woven fabric, and W is the content of the amphiphilic polymer per unit area of ​​the polypropylene fiber membrane.

[0126] The test method for the specific surface area of ​​super-spread polypropylene fiber membrane is as follows: Use a mercury intrusion instrument to test, weigh a certain mass of sample, transfer it into a dilatometer, and then seal and weigh it; put the weighed dilatometer into a low-pressure chamber, and then perform a high-pressure test, and calculate the specific surface area result through software.

[0127] The treatment rate refers to the amount of water sprayed on the super-spread polypropylene fiber membrane. The treatment rate can be controlled by the pump in the feed device. Calculation method: treatment rate = water pump feed rate / membrane area.

[0128] In the following examples, polyvinyl alcohol, PVA-1799, has a degree of polymerization of 1700 and a degree of alcoholysis of 99%.

[0129] Preparation Example 1

[0130] Take polypropylene meltblown nonwoven fabric (purchased from Yanshan Petrochemical, specification 25g / m 2 , fiber diameter 0.5-8 microns) was immersed in a 0.3wt% polyvinyl alcohol (PVA-1799 from Sinopharm, glass transition temperature 72°C) aqueous solution at 25°C, and ultrasonically treated at a frequency of 50kHz for 30 minutes under a 250W ultrasonic probe. The treated polypropylene melt-blown was placed in a 0.5wt% glutaraldehyde cross-linking solution (pH 6) and cross-linked in a 60°C oven for 1 hour. The cross-linked polypropylene melt-blown was cleaned three times in a 100W ultrasonic water bath at a frequency of 50kHz, each time for 20 minutes, and then dried (at 60°C for 1 hour) to obtain an ultra-spread polypropylene fiber membrane.

[0131] The obtained polypropylene fiber membrane was tested for water contact angle, specific surface area, spreading time, etc. The specific test data are shown in Table 1.

[0132] Preparation Example 2

[0133] Take a three-layer composite fiber membrane of polypropylene spunbond nonwoven fabric and polypropylene meltblown fabric (purchased from Yanshan Petrochemical, model SMS, specification 50g / m 2 , fiber diameter 0.5-45 μm). Except that the ultrasonic treatment time during immersion in the polyvinyl alcohol aqueous solution was changed to 50 minutes, the rest was the same as in Example 1 to obtain an ultra-spread polypropylene fiber membrane. The specific test data are shown in Table 1.

[0134] Preparation Example 3

[0135] Take the polypropylene melt-blown nonwoven fabric in Preparation Example 1 and soak it in a 0.1wt% polyvinyl alcohol (from Aladdin, PVA-1799) aqueous solution at 25°C, and ultrasonically treat it at a frequency of 50kHz for 30 minutes under a 250W ultrasonic probe. The treated polypropylene melt-blown is arranged in a 0.5wt% glutaraldehyde cross-linking solution (pH is 6) and cross-linked in an 80°C oven for 1h. The cross-linked polypropylene melt-blown is arranged in a 100W ultrasonic water bath and cleaned three times at a frequency of 50kHz, each time for 20 minutes, and then dried (at 85°C for 1h). The glass transition temperature of PVA-1799 is 72°C. Specific test data are shown in Table 1 to obtain a modified polypropylene fiber membrane.

[0136] Preparation Example 4

[0137] PVA 1750 (purchased from Shandong Jiaying Chemical Technology Co., Ltd.) was mixed with deionized water at 90°C to form a concentrated aqueous solution with a concentration of 0.8 wt%. 500 ml of PVA solution was weighed and mixed with 600 ml of cross-linking solution to obtain a mixed solution. The cross-linking solution contained 45 ml of glutaraldehyde aqueous solution (50 wt%), acetic acid aqueous solution (10 vol%), methanol aqueous solution (10 vol%), and sulfuric acid aqueous solution (10 vol%), and the volume ratio of the three was 3:2:1. Polypropylene melt-blown nonwoven fabric (Sinopec Yanshan Petrochemical, with a surface density of 25 g / m 2 ) was placed in the mixed solution and vibrated at 150 rpm in a shaking incubator at 50°C for 60 minutes, then placed in deionized water for 1 hour to remove the residual crosslinking agent and PVA, and finally dried in a 50°C oven for one hour to obtain a modified polypropylene fiber membrane. The specific test results are shown in Table 1.

[0138] Preparation Example 5

[0139] The concentration of the PVA aqueous solution was changed to 0.1 wt %, the cross-linking agent was changed to boric acid, the mass fraction of the cross-linking agent was 0.5 wt %, the cross-linking time was 90 minutes, and the remaining operations were the same as those in Preparation Example 1. The specific test data are shown in Table 1.

[0140] Example 1

[0141] Take 2000g of salt water (containing 23.5% by mass of Na2SO4 in the water), and use the super-spread polypropylene film (i.e., super-spread polypropylene non-woven fabric) obtained in Preparation Example 1 as the accelerated evaporation membrane, with a width of 0.25m, a length of 2m, and a membrane area of ​​0.5m 2 , weighing about 12.6g. To speed up the evaporation rate, preheat the brine to 60°C and then add it to the water inlet assembly. The water inlet assembly consists of a water pump and a silicone tube. The water pump flow rate is 150ml / min, Chongqing Jieheng Peristaltic Pump Co., Ltd., and the silicone tube diameter is 10mm. The brine is dripped onto the surface of the accelerated evaporation membrane at a rate of 150ml / min through the water inlet assembly and then spreads rapidly, and the evaporation membrane rotates with the movement of the transmission module, so that the water is evenly dripped on the surface of the evaporation membrane. The transmission speed is 1m / min. In order to speed up evaporation and promote the flow of water-containing air in the equipment, dry air is blown into the equipment through a blower, Suzhou Pu Jin Electromechanical, 130FLJ0, 60w. The specific work flow is:

[0142] (1) The conveying module starts to rotate and the blower starts to work; (2) The water inlet assembly and the condensed water collection assembly start to work; (3) The water inlet assembly is paused after two minutes of operation to allow the water spread on the evaporation membrane to have sufficient time to evaporate; (4) After a pause of 7 minutes, the water inlet assembly continues to work; (5) Steps (3) and (4) are repeated until 2000 ml of brine is processed, which takes 45 minutes.

[0143] After treatment, 1520g of condensed water was collected, the mass of the evaporation film was 336g, and 142g of salt was collected in the salt collection device. The processing speed was 18000ml / h·m 2 The condensed water was subjected to ICP analysis and the results showed that the sodium ion content was 20.49 mg / L.

[0144] Example 2

[0145] The super-spread polypropylene fiber membrane obtained in Preparation Example 2 was used to replace the super-spread polypropylene fiber membrane in Example 1. The water inlet rate was 100 ml / min, and the amount of brine and other conditions remained unchanged. After treatment, 1523 g of condensed water was collected, the mass of the evaporation membrane was 407 g, and 70 g of salt was collected in the salt collection device. The treatment rate was 12000 ml / h·m 2 .

[0146] Comparative Example 1

[0147] The modified polypropylene fiber membrane obtained in Preparation Example 3 was used to replace the ultra-spread polypropylene fiber membrane in Preparation Example 1 in Example 1, and the rest remained unchanged.

[0148] Since the preparation example 3 cannot be spread and has poor hydrophilicity, water falls off after the fiber membrane moves, and the salt water separation cannot be achieved. The amount of collected condensed water is far lower than that of all the examples.

[0149] Comparative Example 2

[0150] The modified polypropylene fiber membrane obtained in Preparation Example 4 was used to replace the super-spread polypropylene fiber membrane in Example 2, and the rest remained unchanged.

[0151] Since the preparation example 4 cannot be spread and has poor hydrophilicity, water falls off after the fiber membrane moves, and the salt water separation cannot be achieved. The amount of collected condensed water is far lower than that of all the examples.

[0152] Example 3

[0153] The super-spread polypropylene fiber membrane obtained in Preparation Example 5 was used to replace the super-spread polypropylene fiber membrane in Example 1. The membrane weight was about 12.5 g. The brine was a sodium chloride aqueous solution with a sodium chloride salt mass content of 3.5%. The amount of brine and other conditions remained unchanged.

[0154] After treatment, 1908g of condensed water was collected, the mass of the evaporation film was 63.6g, and 18g of salt was collected in the salt collection device. ICP analysis of the condensed water showed that the sodium ion content was 21.2mg / L. The processing speed was 18000ml / h·m 2 .

[0155] Table 1

[0156]

[0157]

[0158] From the comparison of the above embodiments and comparative examples, it can be seen that the brine separation device in the present invention can utilize the excellent spreading performance and large specific surface area of ​​the super-spread fiber membrane. When the brine is spread in the fiber membrane, rapid evaporation of water can be achieved, and salt crystals are precipitated in the process, which are easy to collect, thereby achieving efficient brine separation.

[0159] It can also be seen from the embodiments of the present invention that the brine separation device of the present invention has a simple structure, is easy to operate, consumes less energy, can meet different brine separation application scenarios, and is easy to promote and implement.

[0160] It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation to the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein, on the contrary, the present invention can be extended to all other methods and applications with the same functions.

[0161] All publications, patent applications, patents and other references mentioned in this specification are incorporated herein by reference. Unless otherwise defined, all technical and scientific terms used in this specification have the meanings conventionally understood by those skilled in the art. In the event of a conflict, the definition in this specification shall prevail.

[0162] When this specification uses the prefix "well-known to those skilled in the art", "prior art" or similar terms to introduce materials, substances, methods, steps, devices or components, etc., the objects introduced by the prefix cover those conventionally used in the art when the present invention was proposed, but also include those that are not commonly used at present but will become recognized in the art as being suitable for similar purposes.

[0163] The endpoints and any values ​​of the ranges disclosed in the present invention document are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be regarded as specifically disclosed in this article. Hereinafter, in principle, each technical solution can be combined with each other to obtain a new technical solution, which should also be regarded as specifically disclosed in this article.

[0164] In the context of the present specification, any matters or items not mentioned are directly applicable to those known in the art without any changes except those explicitly stated.

[0165] Moreover, any embodiment described in this document may be freely combined with one or more other embodiments described in this document, and the technical solutions or technical ideas formed thereby are deemed to be part of the original disclosure or original record of the present invention, and should not be regarded as new content that has not been disclosed or anticipated in this document, unless a person skilled in the art considers that the combination is obviously unreasonable.

Claims

1. A salt water evaporation and separation device, comprising a feed assembly, an evaporation and separation assembly, a salt collection assembly and a condensed water collection assembly; wherein: The evaporation separation component includes an ultra-spread polypropylene fiber membrane; The feed assembly can distribute the salt water from the outside on the surface of the super-spread polypropylene fiber membrane in the evaporation separation assembly; the salt water can be super-spread on the surface of the super-spread polypropylene fiber membrane, and then evaporated to obtain water vapor and precipitated salt respectively; the salt collection assembly and the condensed water collection assembly are used to collect the salt and water vapor respectively; The super-spread polypropylene fiber membrane contains a polypropylene fiber membrane matrix and an amphiphilic polymer. Taking the mass of the super-spread polypropylene fiber membrane as 100%, the content of the polypropylene fiber membrane matrix in the super-spread polypropylene fiber membrane is 93%-99.99%; the content of the amphiphilic polymer is 0.01%-7%.

2. The salt water evaporation separation device according to claim 1, characterized in that: Taking the mass of the super-spread polypropylene fiber membrane as 100%, the content of the polypropylene fiber membrane matrix in the super-spread polypropylene fiber membrane is 95%-99.95%; the content of the amphiphilic polymer is 0.05%-5%; and / or, The super-spread polypropylene fiber membrane is a super-hydrophilic polypropylene fiber membrane without a layered structure; and / or, The content of the amphiphilic polymer per unit surface area of ​​the super-spread polypropylene fiber membrane is 0.005 g / m 2 -3g / m 2 , preferably 0.005g / m 2 -2g / m 2 .

3. The salt water evaporation separation device according to claim 1, characterized in that: The fiber diameter of the super spread polypropylene fiber membrane is below 20 microns, preferably below 10 microns, more preferably 0.1-10 microns; and / or, The amphiphilic polymer is selected from polyvinyl alcohol and / or a cross-linked polymer formed by polyvinyl alcohol and a cross-linking agent; the cross-linking agent is preferably selected from at least one of a polyacid and a polyaldehyde, more preferably glutaraldehyde and / or boric acid; and / or, The super-spread polypropylene fiber membrane contains polypropylene fibers coated with an amphiphilic polymer. Preferably, the amphiphilic polymer is self-assembled and coated on the polypropylene fibers through capillary force.

4. The salt water evaporation separation device according to claim 1, characterized in that: The method for preparing the super-spread polypropylene fiber membrane comprises contacting a polypropylene fiber membrane substrate with a solution containing an amphiphilic polymer under the action of an external force, wherein the content of the amphiphilic polymer in the solution containing the amphiphilic polymer is not higher than 5wt%, and optionally subjecting the polypropylene fiber membrane obtained after the polypropylene fiber membrane substrate is contacted with the amphiphilic polymer to a cross-linking reaction in a solution containing a cross-linking agent to obtain the super-spread polypropylene fiber membrane; preferably, The contacting is carried out in a solution containing an amphiphilic polymer; and / or, The contact utilizes intermolecular forces to cause the amphiphilic polymer to self-assemble on the surface of the polypropylene fiber membrane, thereby obtaining a polypropylene fiber membrane coated with the amphiphilic polymer.

5. The salt water evaporation separation device according to claim 4, characterized in that: The content of the amphiphilic polymer in the solution containing the amphiphilic polymer is 0.05-4.5 wt %, preferably 0.1-4.5 wt %; and / or, The preparation method further comprises a step of drying the polypropylene fiber membrane matrix after contacting the amphiphilic polymer; preferably, The contacting temperature and the drying temperature each do not exceed the melting temperature of the fiber membrane matrix and the amphiphilic polymer, and more preferably do not exceed the glass transition temperature of the amphiphilic polymer.

6. The salt water evaporation separation device according to claim 4, characterized in that: The amphiphilic polymer is selected from polyvinyl alcohol; and / or, The surface density of the polypropylene fiber membrane substrate is 10-60 g / m 2 , preferably 20-50g / m 2 , and / or, the fiber diameter in the polypropylene fiber membrane matrix is ​​not greater than 20 microns, preferably less than 10 microns, more preferably 0.1-10 microns.

7. The salt water evaporation separation device according to any one of claims 1 to 6, characterized in that: The super-spread polypropylene fiber membrane has at least one of the following characteristics: The maximum size of the spreading area after a droplet with a volume of 2 μL is spread on the super-spread polypropylene fiber membrane is not less than 7 mm, the maximum size of the spreading area after a droplet with a volume of 5 μL is spread on the super-spread polypropylene fiber membrane is not less than 8 mm, the maximum size of the spreading area after a droplet with a volume of 8 μL is spread on the super-spread polypropylene fiber membrane is not less than 12 mm, and the maximum size of the spreading area after a droplet with a volume of 12 μL is spread on the super-spread polypropylene fiber membrane is not less than 15 mm; and / or, The weight of the super spread polypropylene fiber membrane per square meter is 9-100 g / square meter, preferably 10-50 g / square meter; and / or, The specific surface area of ​​the super spread polypropylene fiber membrane is greater than 0.3 m2 / g, preferably greater than 0.7 m2 / g; and / or, The super-spreading polypropylene fiber membrane has a static contact angle of water reaching 0 degrees within no more than 1 second, preferably within 0.005 seconds to 1 second.

8. The salt water evaporation separation device according to any one of claims 1 to 6, characterized in that: The liquid outlet end of the feed assembly and the super-spread polypropylene fiber membrane can move relative to each other to distribute the brine delivered by the liquid outlet end of the feed assembly on the upper surface of the super-spread polypropylene fiber membrane; preferably, The liquid outlet end of the feed assembly is fixedly arranged, and the super-spread polypropylene fiber membrane can move in a horizontal direction or can intermittently flip around an axis in a horizontal plane. Preferably, the super-spread polypropylene fiber membrane can move in a circular manner in a horizontal direction; or, The liquid outlet end of the feed assembly can move in a horizontal direction, and the super-spread polypropylene fiber membrane is stationary or intermittently flips around an axis in a horizontal plane or can move in a circular manner in a horizontal direction.

9. The salt water evaporation separation device according to claim 8, characterized in that: The liquid outlet end of the feed component is a water pipe and / or a nozzle; the evaporation separation component includes a super-spread polypropylene fiber membrane and a transmission module capable of driving the super-spread polypropylene fiber membrane to move in a horizontal circular direction; preferably, the transmission module includes an annular conveyor belt; more preferably, the annular conveyor belt has a mesh structure.

10. The salt water evaporation separation device according to any one of claims 1 to 6, characterized in that: The evaporation separation component further includes an air blowing module; and / or, The evaporative separation component comprises a reinforcing material disposed below the super-spread polypropylene fiber membrane; preferably, the reinforcing material is selected from at least one of a hydrophilic membrane, a hydrophilic and / or non-hydrophilic mesh material.

11. The salt water evaporation separation device according to any one of claims 1 to 6, characterized in that: The salt water evaporation separation device comprises a shell, an evaporation separation component arranged in the inner cavity of the shell, a feed component and a condensed water collection component arranged on the shell and connected to the inner cavity of the shell; and / or, The salt collection component is arranged below the evaporation separation component, or is arranged below the shell and communicated with the inner cavity of the shell through a closable discharge port; and / or, The lower part of the salt water evaporation separation device is also provided with a liquid outlet, and preferably, the liquid outlet is communicated with the feed assembly.

12. A method for evaporating and separating salt water using the salt water evaporation and separation device according to any one of claims 1 to 11, comprising the following steps: (1) distributing the brine on the super-spread polypropylene fiber membrane of the evaporation separation component through a feed component; (2) the salt water is super-spread on the surface of the super-spread polypropylene fiber membrane, and water vapor and salt precipitated from the super-spread polypropylene fiber membrane are obtained by evaporation; (3) The water vapor is collected by a condensed water collection component to obtain condensed water; and the precipitated salt is collected by a salt collection component to obtain salt.

13. Use of the salt water evaporation separation device according to any one of claims 1 to 11 or the method according to claim 12 in the fields of seawater desalination and concentrated brine treatment in chemical plants.

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