963 results about "Membrane distillation" patented technology

The present invention provides composite membranes for membrane distillation and related methods of manufacture. In particular, there is provided a composite hydrophilic/hydrophobic membrane comprising a hydrophilic polymer layer and a hydrophobic polymer layer comprising fluorinated surface-modifying macromolecules, wherein said composite membrane has a high vapour flux. Also provided herein are methods of manufacturing and optimizing the composite membranes and a membrane distillation system comprising the composite membranes.

The invention relates to a preparation method of an electrostatic spinning hydrophobic nanofiber porous membrane for membrane distillation. The method comprises the following steps of: dissolving a hydrophobic functional polymer material in the solvent to get a 1-35wt% polymer spinning solution, performing electrostatic spinning to get a hydrophobic nanofiber porous membrane, and further performing thermal treatment, thereby obtaining the electrostatic spinning hydrophobic nanofiber porous membrane for membrane distillation. The preparation method provided by the invention is simple and practicable, and can be used for conveniently and accurately controlling the thickness and uniformity of the nanofiber membrane and realizing operations of mass production more easily; the high-hydrophobicity nanofiber porous membrane prepared by the preparation method can be used for signally improving the defects of the conventional membrane for membrane distillation that the water flux is low and the membrane pores get wet easily, so that the membrane distillation technology can compete with a reverse osmosis technology in the seawater desalination field.

DCMD and VMD systems and methods for use in desalination applications are provided. The DCMD and VMD systems employ coated porous hydrophobic hollow fiber membranes. The coatings advantageously function to essentially eliminate pore wetting of the membrane, while permitting substantially unimpeded water vapor permeance through the fiber walls. The DCMD and VMD membranes are characterized by larger fiber bore diameters and wall thicknesses. The membranes substantially reduce the loss of brine sensible heat, e.g., heat loss via conductive heat flux through the membrane wall and the vapor space and, in exemplary embodiments, the brine-side heat transfer coefficient is dramatically enhanced by horizontal/vertical cross flow of brine over the outside surface of the coated fibers. Superior water vapor fluxes are achieved with the systems and methods.

The invention provides a preparation method of a super-hydrophobic membrane. The preparation method comprises steps as follows: hydrophobic organic polymer materials and nano granules are dissolved in an organic solvent, the mixture is stirred and left to stand, and an electrostatic spinning solution is prepared; high-pressure electrostatic spinning parameters are set, electrostatic spinning membrane preparation is performed, and a nanofiber membrane is obtained and subjected to thermal treatment; TiO2 is prepared, the surface of the nanofiber membrane is covered with TiO2, and thermal treatment, water-bath heating, washing and ultraviolet radiation treatment are performed; silane solutions are prepared, the nanofiber membrane surface covered with TiO2 is covered with the silane solutions, thermal treatment, washing and airing are performed, and the super-hydrophobic membrane is obtained. The invention further provides an application of the super-hydrophobic membrane in the membrane distillation process. By means of the method, the super-hydrophobic nanofiber membrane is prepared. The membrane simultaneously has super-hydrophobicity and high throughput performance, the wet resistance of the membrane is effectively improved, and the service life of the membrane is prolonged.

Embodiments of the present invention seek to provide a membrane distillation system having compact design and simplified connection system for fluid flow paths used in the system. According to one aspect, a membrane distillation system includes at least one membrane module and at least one like configured heat exchanger module, the modules being supported and connected to like configured manifold devices for providing fluid communication between said modules.

The invention belongs to the field of sewage treatment, and particularly relates to a waste water treatment method and device based on forward osmosis and membrane distillation. The waste water treatment method based on the forward osmosis and membrane distillation comprises a waste water concentration process and a drive liquid circulation process, wherein the waste water concentration process adopts a forward osmosis technology to concentrate waste water with high salt content and high chemical oxide demand (COD) concentration through drive liquid so as to obtain the concentrated waste water and diluted drive liquid; the drive liquid circulation process adopts a membrane distillation technology to dehydrate the diluted drive liquid so as to obtain the purified water and renewable drive liquid; and the renewable drive liquid is repeatedly used for the waste water concentration process so as to continuously concentrate the waste water. Due to the adoption of the method and device for treating the waste water with high salt content and high COD concentration, the waste water of different sources and fields can be treated, and the advantages such as wide applicability for waste water, stability in running and low treatment cost can be realized.

The invention discloses a recycling method of high brine waste water based on forward osmosis. The method comprises the following steps: firstly, concentrating high brine waste pretreated through a forward osmosis membrane element, wherein water in waste water enters into a driving liquid from a raw material side of a forward osmosis membrane; and then, concentrating, dehydrating and regenerating the diluted driving liquid obtained through one or more of a membrane distillation membrane element, a membrane distillation evaporation assembly or a low temperature multi-effect evaporation assembly, wherein regenerated driving liquid is recycled in the process of returning to forward osmosis. The method is widely applicable for the type of waste water, and has the advantages of long-term stable operation and low treatment cost.

The invention discloses a membrane-process integration salt recovering and biochemical processing method for waste water from high-salinity epoxy resin production, purifying and splitting waste water, i.e. processing the washing waste waters of different salinities and concentrations, respectively: concentrating little amounts of waste water with high salinity and high concentration by membrance distillation integration technique and screening out salt; preprocessing large amounts of rinsing waste water with low salinity and low concentration of organic matters and then processing in a two-stage biochemical processing system, to meet the specified effluent standard. And it largely solves the problem of serious inhibition of high-salinity organic waste water to the biotreatment and adopts salt recovering and water recycling processes, and large amounts of waste heat can serve as a heat source of membrane distillation and the afterheat of the waste water can be used by the membrane distillation.

The present invention relates to a preparation method for a microporous membrane having a multi-scale gradient micro-structure surface. The method comprises: fixing a screen mesh on the upper surface of a rough flexible substrate, coating a polymer solution layer with a thickness of 50-500 mum on the upper surface of the screen mesh at a constant speed, curing, washing, and carrying out simple mechanical peeling to remove the rough flexible substrate to obtain the microporous membrane having the multi-scale gradient micro-structure surface. According to the present invention, the process of the method is simple, the membrane area can be controlled, continuous production can be achieved, mechanical properties of the membrane are high, and the membrane has super-hydrophobic or super-hydrophilic property, wherein the super-hydrophobic membrane has super-lipophilic property, and the super-hydrophilic membrane has super-oleophobic property under water and has super-hydrophobic property under oil; and the obtained membrane can be adopted to effectively separate various oil and water mixtures including nano-scale oil water emulsions, and can further be used in fields of self-cleaning ultrafiltration/microfiltration membrane sewage treatments, medical sterilization, food turbidity removal, sterilization, material separation, membrane distillation, and the like.

The invention provides a method for treating high-salt water by air stripping type membrane distillation. In the method, an air compressor is arranged in the system, a hydrothermal circulation pump and the air compressor jointly generate a gas-liquid two phase flow on a high-temperature side of a hydrophobic membrane, an electromagnetic valve is arranged on an air pipe, and pulse air intake is formed by the intermittent opening and closing of the electromagnetic valve. The method can effectively control membrane pollution and ensures the stable and high-efficiency operation of a membrane distillation device. The method has the main advantages of effectively relieving the concentration polarization of membrane distillation and preventing the formation of a gel layer due to the scraping effect of air bubbles on membrane surfaces in the gas-liquid two phase flow, and improving the turbulence scale of the membrane surfaces, increasing the membrane surface flow rate, reducing the concentration of membrane surface salt solution and increasing membrane permeation flux due to the adoption of pulse air intake. Air passing through a membrane component can be used for cooling membrane distillation penetrating fluid. The method of the invention can treat salt water with an extremely high concentration.

The invention discloses a preparation method of a teflon hollow fiber membrane for membrane distillation, which comprises the following steps of: mixing teflon dispersion powder and a extruding-aid agent, pressing a blank, extruding the blank into a teflon hollow tube through a pushing and pressing machine with a cone mould and a mouth mould, and performing longitudinal stretch, sintering and heat setting on the teflon hollow tube in a drying oven to obtain the teflon hollow fiber membrane. The processed teflon hollow fiber membrane is in an asymmetric structure, the mean pore size of an outer layer is 0.10-1.0 micrometer, the mean pore size of an inner layer is 5.0-20 micrometers, the wall thickness is 0.1-0.5 millimeter, the bubble point pressure is 0.5-2.0 kgf/square centimeter, and the water resistance pressure is 1.5-6kgf/square micrometer. The invention is mainly used for the membrane distillation separation process, and can be applied to the fields of sea water desalination, industrial wastewater treatment, cryoconcentration of food and biological products, and the like.

The invention relates to a solution regeneration unit for a solution dehumidification air-conditioning system based on the membrane distillation technology, which mainly comprises a diluted solution reservoir, a concentrated solution reservoir, a solution heating device, a regenerative circulating pump, a water vapor treatment module and a membrane distillation component. By utilization of the characteristic in the membrane distillation technology that the temperature of driving heat source is low, the heat source temperature required by the solution regeneration process is greatly reduced, and the available temperature difference range of heat energy is increased; meanwhile, by utilization of the large contact area provided by a membrane component under unit volume and the expandability of the membrane component, the volume and the weight of a solution regeneration system are greatly reduced. Compared with the prior packed tower solution regeneration unit, the solution regeneration unit has low operating temperature and the heat energy during the operating process is only used for transmembrane latent heat transfer of water vapor, so that the energy consumption is small.

The invention relates to a vacuum membrane distillation (VMD) device and a method used for carrying out heat recovery effectively, comprising a membrane distillation system, a heat recovery system, a heating equipment, a vacuum equipment, a liquid circulation system, a pre-disposal system, system control and detection. The vacuum membrane distillation (VMD) device and the method can utilize low-temperature heat source, and have high heat utilization ratio, high desalinization ratio and wide application range.

The invention relates to a device and a method for treating high-salt wastewater by forward osmosis technology, belonging to the technical field of water treatment. The pretreated high-salt wastewater first passes through the fresh water chamber of the electrodialyzer, and the ions in the wastewater migrate to the concentrated water chamber under the driving force of the concentration difference and the potential difference, so that the salt content in the wastewater is reduced to a level suitable for forward osmosis. Conditions of technical processing. Then it is further concentrated through the forward osmosis membrane element, the water in the wastewater enters the draw liquid side from the raw material liquid side of the forward osmosis membrane, and then the obtained diluted draw liquid is concentrated, dehydrated and regenerated through the membrane distillation membrane module, and the concentrated draw The liquid is recycled in the forward osmosis process, and very pure product water is obtained. The method has wide applicability to high-salt wastewater, and has the advantages of long-term stable operation and high economic benefits.

The invention discloses a method for preparing methionine and recovering a by-product-carbon dioxide. The method comprises the steps that a methionine salt and carbonate mixed solution obtained by hydrolyzing methylmercapto-ethyl hydantoin with alkali is filtered through a microporous membrane, and then filtrate is delivered to a bipolar membrane electrodialysis system to be subjected to electrodialysis treatment, so that acid liquor A and alkali liquor A are obtained; the alkali liquor A is treated continuously and cyclically, and the acid liquor A is subjected to gas-liquid separation, so that gaseous carbon dioxide and acid liquor B are obtained; the acid liquor B is delivered back into the bipolar membrane electrodialysis system to be subjected to cyclic treatment till the pH value of the acid liquor B is 3.8-4.5, the reaction is completed, a methionine solution is prepared, and the methionine is prepared through concentration and crystallization of the methionine solution; the gaseous carbon dioxide is introduced into an absorption cell, and carbon dioxide on the upper portion of the absorption cell absorbs mother liquor, is subjected to membrane distillation and concentration and then is circulated back to the absorption cell; carbonate crystals are grown at the bottom of the absorption cell and guided out from the bottom of the absorption cell; and carbonate is recovered through solid-liquid separation. According to the method for preparing the methionine and recovering the by-product-carbon dioxide, the gaseous carbon dioxide is recycled, so that carbon emission is reduced, and energy resources are saved through the membrane distillation technique.

The invention provides a nanofiber membrane for membrane distillation and a preparation method of the nanofiber membrane. The nanofiber membrane consists of nanofibers and nano branch structures distributed on the nanofibers. According to the method, a spraying (or atomizing) technology and an electrostatic spinning technology can be simply implemented synchronously, and the nanofiber membrane with superhydrophobic property for membrane distillation is prepared in a combined manner. The preparation method is simple, the process is easy to control, complicated preparation steps and expensive post treatment equipment are not required, the prepared nanofiber membrane is high in porosity, the surface of the membrane has uniform and excellent super-hydrophobicity, the plane, which is formed by the nanofibers, of each layer in the nanofiber membrane has the super-hydrophobicity, and therefore, the wetting resistance of the membrane can be greatly improved. The problems of low membrane flux and easiness in wetting are solved effectively.

A membrane distillation apparatus using solar energy or afterheat to treat water is composed of membrane assembly, solar heat or afterheat collector, more than one circulating pumps and its driver, and pipeline. Its advantages are no need of electric energy, and continuous treatment of water.

The invention discloses a preparation method of a hydrophobic PVDF (Polyvinylidene Fluoride) microporous membrane with a beta crystalline phase structure. The preparation method comprises the following steps of: dissolving ionic liquid and polyvinylidene fluoride into an organic solvent I and stirring for at least 8 hours to prepare uniform membrane formation solution; defoaming the membrane formation solution, scraping a primary flat plate liquid membrane of 150-250 mum on a flat plate carrier, remaining in air for 30-50 seconds and soaking the primary flat plate liquid membrane into a solidification bath to cure and form a membrane; and soaking the membrane formed by curing and membrane formation in de-ionized water to prepare the hydrophobic PVDF microporous membrane with the beta crystalline phase structure. The invention also discloses the hydrophobic PVDF microporous membrane with the beta crystalline phase structure prepared by the method. The preparation method of the hydrophobic PVDF microporous membrane with the beta crystalline phase structure has the advantages of simple process and low preparation cost; and the prepared PVDF microporous membrane has strong hydrophobicity and has excellent application value in the aspects of membrane distillation, oil/water separation and the like.

The invention discloses a hydrophobically modified distillation membrane material of high throughout and high salt rejection rate and its application. For the material of the invention, ultrafiltration or microfiltration membrane materials are employed as the basic membrane material, the surface of which is subjected to cleaning and etching pretreatment by means of drying and plasmas. Then the surface of the basic membrane material is modified with a modification material by gas phase, liquid phase or plasma modification, thus obtaining the hydrophobically modified distillation membrane material of high throughout and high salt rejection rate. The invention discloses a novel hollow fiber membrane material with hydrophobic surface modification, and the membrane material is characterized by high throughout, high salt rejection rate and high stability. The distillation membrane material provided in the invention can be used for direct contact membrane distillation or sweeping gas membrane distillation or vacuum membrane distillation, and is applicable to the treatment of seawater, reverse osmosis concentrated wastewater and industrial wastewater, and the concentration of biomass solution, protein solution and fruit juice.

The invention relates to a method for synergistic treatment and harmless cyclic utilization of refuse fly ash by using a cement kiln. The method for synergistic treatment and harmless cyclic utilization of refuse fly ash by using thecement kiln comprises a three-stage washing desalination technology, a technology of removing heavy metals by coagulation and sedimentation, a membrane distillation concentration technology, a technology of removing slight trace carnallite and a triple-effect evaporation crystallization technology, wherein the three-stage washing desalination technology can remove heavy metals and chloride ions in the fly ash, and the fly ash which contains water and dioxin and the fly ash which contains less than 1% of chlorine ions enter the cement kiln and are incinerated at the temperature of above 1400 DEG C to turn into cement raw materials, and the dioxin is split at the temperature of above 800 DEG C; the technology of removing the heavy metals by coagulation and sedimentation can remove multiple metal ions in the fly ash, and precipitates are dried in advance and then enter the cement kiln to be incinerated; the membrane distillation concentration technology can remove the rest of chloride ions in a solution, and generated distilled water can be recycled; the technology of removing the slight trace carnallite can remove the slight trace carnallite, and heat energy can be recycled; and the triple-effect evaporation crystallization technologyevaporates and separates high salt content concentrated liquid to obtain industrial salt which is used for a paper making technology, snow-melting agents and chloro-alkali industries.

The invention provides a zero discharge method of stainless steel cold rolling acidic waste water concentrated liquid, which orderly comprises the following steps: (1) softening, and coagulating sedimentation; (2) pH adjustment; (3) filtration; (4) membrane distillation, that is, heating the waste water concentrated liquid treated in step (3) to 55-75 DEG C, allowing the waste water concentrated liquid to enter a membrane distillation assembly, wherein the obtained condensed water can be recycled for production; (5) evaporative crystallization, that is, allowing the concentrated liquid discharged after membrane distillation treatment in step (4) to enter an evaporating crystallizer for evaporative crystallization to obtain crystal slurry, heating the crystal slurry in a heating chamber to 95-100 DEG C, allowing the heated crystal slurry to enter a crystallization chamber, boiling the crystal slurry to allow the solution to reach a saturation state, and discharging the generated crystals. The zero discharge method of the invention carries out membrane distillation and evaporative crystallization treatment of concentrated liquid generated by reverse osmosis desalination treatment of stainless steel cold rolling waste water, recycles obtained pure water for production, converts inorganic salt in the concentrated liquid into solids, realizes zero discharge of waste water, and has good social benefit and environment benefit.

A desalination system wherein a latent heat of condensation produced by the temperature gradient across a membrane distillation (MD) module is transferred directly to a latent heat of vaporization during desalination of a liquid flow stream. The desalination system comprises the MD module disposed within an object and configured to receive an input feed stream for desalination and produce an output flow stream of a product. The system also comprises a vapor compressor in fluidic communication with the MD module and configured to introduce a hot steam to a high temperature side of the MD module and extract a cool steam, having a temperature less than the hot steam, from a low temperature side of the MD module, thereby creating a temperature gradient across of the MD module. A desalination method is also presented.

The invention discloses a preparation method of a super-hydrophobic electrostatic spinning polydimethylsiloxane membrane. The preparation method comprises the steps that a substrate organic polymer material is dissolved in an organic solvent, and an electrostatic spinning base solution is prepared through high-temperature stirring; the functional organic polymer material and nano particulate matter are dissolved in the electrostatic spinning base solution prepared in the step 1, and an electrostatic spinning solution is prepared through high-temperature stirring and high-temperature standing; the parameters of an electrostatic spinning correlated instrument and environmental parameters are set, electrostatic spinning membrane forming is performed by using the electrostatic spinning solution to obtain the electrostatic spinning polydimethylsiloxane membrane; the electrostatic spinning polydimethylsiloxane membrane is subjected to heat treatment and standing cooling. The invention further provides the super-hydrophobic electrostatic spinning polydimethylsiloxane membrane and application of the super-hydrophobic electrostatic spinning polydimethylsiloxane membrane in a membrane distillation process. The preparation method is simple, a preparation process is easy to control, the preparation cost is low, the preparation time is shorter, the water contact angle of the membrane is large, and the membrane can be directly applied to the membrane distillation process and is high in flux and long in service life.