34 results about "Membrane method" patented technology

The application provides a membrane seawater desalination system for large temperature difference and a control method, the membrane seawater desalination system for large temperature difference comprises a water supply module, a high-pressure module, a reverse osmosis desalination module, an energy recovery module and a PLC controller, the high-pressure module comprises M sets of high-pressure pump groups arranged in parallel, the high-pressure pump group comprises a booster high-pressure pump and a high-pressure pump arranged in series along the water flow direction; the energy recovery device has N sets of energy recovery devices corresponding to the reverse osmosis devices in the reverse osmosis desalination module one by one, wherein M < N; each set of energy recovery device is matched with one energy recovery booster pump and one second water supply pump simultaneously. The first water supply pump, the second water supply pump, the high-pressure pump, the booster high-pressure pump, the energy recovery booster pump and the low-pressure circuit and the high-pressure circuit are optimally combined, so that the number of high-pressure pumps and the use of high-power frequency converters are reduced, the investment cost is reduced, and the system operation efficiency and the safety redundancy are improved.

The application belongs to the technical field of seawater desalination equipment, and particularly relates to a low-pressure membrane method seawater desalination device and method, which comprises a water pump and a desalination device in conductive connection; a water pumping pipe is arranged on the input end of the water pump; the output end of the water pump is in conductive connection with the desalination device; the desalination device comprises a shell, a membrane cylinder and an anti-corrosion and moisture-retention mechanism; the moisture-retention plate, the water storage layer and the chemical agent adding device are arranged, the moisture-retention plate and the water storage layer are attached to the membrane cylinder by the change of the water pressure in the desalination cavity after the seawater desalination device is used, the addition of the chemical agent forms an antibacterial and anti-corrosion environment on the surface of the membrane cylinder, the water absorbed by the water storage layer can continuously moisten the membrane cylinder, the probability of the reverse osmosis membrane of the membrane cylinder drying and shrinking is reduced, the growth of microorganisms is inhibited, a suitable environment for the preservation of the membrane cylinder is created, and the service life of the membrane cylinder is prolonged.

The invention belongs to the technical field of seawater desalination equipment, and particularly relates to a low-pressure membrane method seawater desalination device and method. A water pumping pipe is mounted at the input end of the water pump, and the output end of the water pump is communicated with the desalting device; the desalting device comprises a shell, a film cylinder and an anti-corrosion moisturizing mechanism; by arranging the moisturizing plate, the water storage layer and the chemical feeder, after the seawater desalination device is used, the moisturizing plate and the water storage layer are attached to the membrane cylinder by utilizing the change of water pressure in the desalination cavity, an antibacterial and anticorrosive environment is formed for the surface of the membrane cylinder by utilizing the addition of a chemical, and meanwhile, the membrane cylinder can be continuously wetted by water absorbed in the water storage layer, so that the service life of the membrane cylinder is prolonged. In the use interval of the seawater desalination device, the probability of drying shrinkage of the reverse osmosis membrane forming the membrane cylinder can be reduced, the growth of microorganisms can be inhibited, a proper environment is created for the preservation of the membrane cylinder, and the service life of the membrane cylinder is further prolonged.

The invention belongs to the technical field of fracturing flow-back fluid treatment, and discloses a fracturing flow-back fluid treatment method and system. The system comprises a fracturing flow-back fluid inlet pipeline, a pretreatment pool, a micron inflation water pump device, a gas storage tank, an air flotation cyclone, a metal film electric flocculation device, a vacuum water storage tank and a two-stage DTL film treatment device. The fracturing flow-back fluid is treated and recycled through a combined process of pretreatment, air flotation rotational flow treatment, metal film electric flocculation treatment and DTL membrane method treatment.

The present invention discloses a membrane carbon capture gas permeability test and evaluation device and method, which relates to the field of membrane separation test technology, including a vacuum pump and at least two membrane pool units, each membrane pool unit is arranged in parallel in sequence, and the upstream of each membrane pool unit is connected in parallel to the downstream of the upstream gas storage tank; the membrane pool unit is provided with a membrane pool structure for separating mixed gases, the downstream of the membrane pool structure in the previous membrane pool unit is connected to the upstream of the membrane pool structure in the next membrane pool unit, the vacuum pump inlet of the vacuum pump is respectively connected to the downstream of the upstream gas storage tank and the downstream of each membrane pool unit, and the inlet and outlet of the gas chromatograph are respectively connected to the downstream of each membrane pool unit and the vacuum pump inlet. The present invention can simply and quickly obtain transmission performance test and evaluation of multiple groups of membrane samples for multiple gases in a wide temperature range and high pressure environment, as well as simultaneously test the separation effect of multiple membrane materials or multi-stage membrane processes on mixed gases, and the test results are highly accurate and repeatable.

The utility model relates to the technical field of filtering devices, in particular to a membrane method water treatment filtering device convenient to replace, which comprises a shunting structure, a shell II, a fixing ring II, a fixing ring III and a filtering structure, the shell II is arranged at the top of the shunting structure, and the fixing ring II is arranged in the middle of the shunting structure; and a third fixing ring is installed at the bottom of the flow dividing structure, a filtering structure is installed on the outer side of a second fixing ring, and the flow dividing structure comprises a supporting column, a first flow dividing pipe, a second flow dividing pipe, a cone, a covering plate, a rotating shaft, a handle and a leak hole plate. According to the utility model, the shunting structure is arranged, and sewage can be shunted through the shunting structure, so that the sewage can only pass through the shunting pipe I or the shunting pipe II, or the shunting pipe I and the shunting pipe II simultaneously, the sewage can be filtered when the filter plate is replaced, and the use is not influenced. The filter structure is arranged, and the filter plate can be quickly mounted and dismounted through the filter structure, so that the use is convenient.

The application discloses a kind of whole membrane method water treatment raw water preheating system method, comprising the following steps: step one: detecting the effluent temperature of raw water pretreatment system;Step two: the effluent of raw water pretreatment system is communicated with water jet tank system and forms loop, and the effluent temperature of water jet tank system is detected;Step three: whether the effluent temperature of raw water pretreatment system meets the next step processing standard is detected, if not, by adjusting the frequency of water pump of water jet tank system, the effluent temperature of raw water pretreatment system is adjusted to be high or low until meeting standard;Step four: whether the effluent temperature of water jet tank system meets water jet tank use standard is detected, if not, by adjusting water temperature through self-circulation cooling system.The application is helpful to solve the problem that whole membrane method water treatment process will heat raw water through high-temperature steam after raw water pretreatment system, with low safety factor and high cost.

The invention discloses a membrane-method seawater desalination system which comprises a first-stage reverse osmosis membrane array, a last-stage reverse osmosis membrane array, a fresh water collection container, a concentrated water collection container and a plurality of electric control switches, and the first-stage reverse osmosis membrane array and the last-stage reverse osmosis membrane array each comprise a plurality of reverse osmosis membrane modules. The reverse osmosis membrane modules are arranged according to a preset matrix mode, the output end of each reverse osmosis membrane module is provided with a fresh water output pipeline and a concentrated water output pipeline, the fresh water output pipelines and the concentrated water output pipelines are provided with electric control switches, and the fresh water output pipelines and the concentrated water output pipelines are connected through control over opening and closing of the electric control switches. The series-parallel connection between the reverse osmosis membrane modules can be realized according to an application scene to adapt to the requirement of quickly producing fresh water, and the fresh water collecting container and the concentrated water collecting container are configured to respectively collect fresh water and concentrated water generated in the seawater desalination process; the technical problems that high-purity fresh water and high seawater desalination efficiency are difficult to obtain according to actual production requirements in an existing membrane method seawater desalination mode are solved.

The embodiment of the invention discloses a copious cooling membrane method oxygen enrichment device which comprises a first container C1, a second container C2, a first oxygen enrichment device, a second oxygen enrichment device and a third oxygen enrichment device, the normal oxygen liquid air production device is used for conveying low-temperature normal oxygen liquid air to the upper part of the tower plate in the first container C1; the blast air production device is used for conveying low-temperature blast air to the lower part of the tower plate in the first container C1; wherein the normal oxygen liquid air production device comprises a second container C2, and a condensation evaporator is arranged in the second container C2; the first container C1 is respectively connected with a normal oxygen liquid air outlet of the condensation evaporator and the top of the second container C2; and the top of the second container C2 is also provided with an oxygen-enriched air leading-out pipeline. According to the technical scheme, under the condition of meeting the rich oxygen demand of a user, refrigeration of an expansion machine is not needed, the technological process is simple, the cost is lower than that of rich oxygen preparation through rectification, and the economic benefits of enterprises are improved.

The utility model relates to the technical field of natural gas desulfurization, in particular to gas pretreatment equipment in a membrane-method natural gas separation and purification process, which comprises a barrel, a gas inlet pipe, a gas outlet pipe, a flat membrane separation component and a purification mechanism, the purification mechanism comprises a rotating shaft, a rotating handle and a plurality of stirring elements, and the gas inlet pipe is fixedly connected with the barrel and positioned at the lower end of the barrel; the air outlet pipe is fixedly connected with the cylinder body and located above the cylinder body, the flat sheet membrane separation component is fixedly connected with the cylinder body and located in the cylinder body, the rotating shaft is rotationally connected with the cylinder body and extends into the cylinder body, the rotating shaft is located below the flat sheet membrane separation component, and the rotating handle is fixedly connected with the rotating shaft and located below the cylinder body. When the natural gas is subjected to membrane treatment desulfurization, moisture in the natural gas is removed through the purification mechanism, so that the moisture is prevented from blocking a flat sheet membrane separation part and damaging equipment, and the service life of the equipment is further prolonged.

The invention relates to the technical field of reclaimed water reuse, and particularly discloses full-membrane-process reclaimed water reuse equipment which comprises a bottom plate, a pretreatment box is fixedly connected to the right side of the top of the bottom plate, a membrane-process reclaimed water recovery mechanism is fixedly connected to the left side of the top of the bottom plate, and an inlet pipeline is fixedly inserted into the left side of the top of the pretreatment box; a discharging pipeline is fixedly inserted into the bottom of the pretreatment box, an impurity filtering assembly is arranged in the pretreatment box and on the right side of the pretreatment box, the impurity filtering assembly comprises an impurity filtering pipe rotationally connected into the pretreatment box, and filtering holes are formed in the annular side of the impurity filtering pipe; a liquid falling assembly used for sprinkling reclaimed water into the impurity filtering pipe is arranged at the bottom of the area, extending into the impurity filtering pipe, of the inlet pipeline, through cooperation of the structures, the interior of the impurity filtering pipe can be scraped by the scraping plate, at the moment, blocked filtering holes can be cleaned and dredged, blockage of the filtering holes is reduced, the influence on the whole filtering process is reduced, and the filtering efficiency is improved. Therefore, the influence on the filtering efficiency is reduced.

The invention relates to the technical field of injection water conveying, in particular to a distribution system for injection water prepared through a membrane method and a control method of the distribution system. A storage tank water inlet is connected with a water source, and an ultrafiltration module is provided with a first ultrafiltration water inlet, a first ultrafiltration water outlet and a second ultrafiltration water outlet; the storage tank water outlet is communicated with the first ultrafiltration water inlet through a first water supply pipeline, the storage tank water return port is communicated with the first ultrafiltration water outlet through a second water supply pipeline, and the third water supply pipeline is used for communicating the second ultrafiltration water outlet with water equipment; the water pump and the ultraviolet sterilization part are both mounted on the first water supply pipeline. The invention aims to provide the distribution system for preparing the injection water by the membrane method and the control method of the distribution system for preparing the injection water by the membrane method aiming at at least one technical problem related in the background technology so as to reduce the energy consumption.

The utility model discloses a digital monitoring and control device for a separation membrane shell stack, and relates to the technical field of membrane separation. In order to solve the technical problem that a device capable of comprehensively and automatically controlling a separation membrane shell group in real time is lacked in the prior art so as to improve the operation efficiency, the reliability and the automation level of a system, the technical scheme provided by the utility model is as follows: the digital monitoring and control device for the separation membrane shell group pile comprises the separation membrane shell group pile, the membrane separation device is used for performing membrane separation on raw water to produce water and concentrated water; the raw water pipeline is used for leading the raw water to the separation membrane shell stack; the concentrated water pipeline is used for discharging concentrated water generated after separation; the produced water pipeline is used for collecting produced water generated after separation; the sensor is used for monitoring the running state of the raw water pipeline in real time; the control system is electrically connected with the sensor and used for receiving the sensing signals and controlling operation of the high-pressure water pump according to the signals. The method is suitable for being applied to the digital monitoring work of the separation membrane shell stack.

The utility model discloses a membrane method agricultural drinking water device combined with oxidation technology, which comprises a main water path, the main water path comprises a water path I, a water path II and a water path III, the input end of the water path I is connected with a water source, the main water path is connected with an ozone generator, the output end of the ozone generator is connected to the water path I, and the output end of the ozone generator is connected to the water path II. The output end of the first water path is connected to the oxidation tank, the output end of the oxidation tank is connected with a second water path, the second water path is connected with a pH adjusting mechanism, the output end of the second water path is connected to the air flotation device, the air flotation device comprises a scum discharge port and a material output port, the material output port is connected with a third water path, and the third water path is connected with the water path. The water path III is connected to a water filtering and purifying mechanism, and the output end of the water filtering and purifying mechanism is connected with a backwashing mechanism for cleaning the water filtering and purifying mechanism and a final output end.

The invention discloses a skid-mounted modular marine membrane method carbon capture system, which comprises a ship tail gas pretreatment pry, a carbon dioxide capture pry and a carbon dioxide liquefaction storage pry, the ship tail gas pretreatment pry is connected with the carbon dioxide capture pry, and the carbon dioxide liquefaction storage pry is connected with the ship tail gas pretreatment pry. And the carbon dioxide trapping pry is connected with the carbon dioxide liquefaction storage pry. The ship tail gas pretreatment pry, the carbon dioxide capture pry and the carbon dioxide liquefaction storage pry are arranged, the absorbed ship tail gas is pretreated to remove dust, desulfurize and denitrate, then the pretreated ship tail gas is subjected to carbon dioxide capture and compression, and high-concentration carbon dioxide is obtained; and finally, the high-concentration carbon dioxide input by the carbon dioxide capture pry is subjected to multi-stage cooling compression, liquefied carbon dioxide is obtained and stored, and ship tail gas integrated comprehensive treatment is achieved based on membrane method carbon capture.

The invention discloses a large membrane-method seawater desalination pretreatment process system. The system comprises an air flotation filter tank, an intermediate water tank and a polymer microporous filter material filter which are arranged in sequence, the air flotation filter tank comprises an air flotation filter tank body, and a filter material layer is arranged in the middle of the air flotation filter tank body; in the air flotation filter tank body, an air flotation area is formed above the filter material layer, and a post-filtration area is formed below the filter material layer; the post-filtration area is connected with the middle water tank through a middle water conveying pipe, and the middle water tank is connected with the macromolecular microporous filter material filter through a middle water output pipe. Compared with a conventional process, the occupied area is greatly reduced, and the investment and operation cost is reduced; according to the method, algae, oil, suspended matters and the like in seawater are removed in the air flotation filter tank, effluent is collected to the middle water tank and then enters the high-molecular microporous filter material filter, the suspended matters are further removed, and the turbidity of the effluent meets the water inlet requirement of membrane-method seawater desalination equipment such as seawater reverse osmosis equipment.

The invention relates to the technical field of separation, and discloses an ultrafiltration device for full membrane method water preparation based on environmental protection and health, the ultrafiltration device comprises a metal outer cavity, the lower surface of the metal outer cavity is provided with supporting legs, the lower surface of the metal outer cavity is fixedly connected with the upper surfaces of the supporting legs, the side surface of the metal outer cavity is provided with a reinforcing batten, and the reinforcing batten is fixedly connected with the supporting legs. The side face of the metal outer cavity is fixedly connected with the right end of a reinforcing batten, a water injection pipeline is arranged at the top end of the reinforcing batten, and the top end of the reinforcing batten is fixedly connected with the lower surface of the water injection pipeline. According to the environment-friendly health-based ultrafiltration device for water preparation by the whole membrane method, the ultrafiltration device is used for performing ultrafiltration on wastewater, a push block interacts with a stirring strip, the stirring strip changes, moves towards a limiting frame seat and penetrates into the limiting frame seat, and the limiting frame seat gradually pushes a descaling sheet to run; and the descaling sheet gradually shovels the adhered sewage falling on the upper surface of the ultrafiltration device, so that the cleanness of the upper part is ensured.

The utility model discloses a mine water treatment microfiltration device applied to a double membrane method, which relates to the technical field of water treatment, and comprises an equipment main body, a treatment tank is arranged in the equipment main body, a microfiltration assembly is arranged in the treatment tank, the microfiltration assembly comprises an outer cylinder, a plurality of through holes are formed in the outer wall of the outer cylinder, and a plurality of through holes are formed in the outer wall of the outer cylinder. An inner barrel for filtering water is arranged in the outer barrel, a driving assembly for driving the inner barrel to rotate is arranged at one end of the inner barrel, a cleaning assembly is arranged above the outer barrel, a conveying assembly is arranged at the other end of the inner barrel, and the conveying assembly extends into the inner barrel. The problems that impurities generated in the cleaning process of an existing micro-filter are left inside and are inconvenient to discharge, the follow-up filtering effect is affected, when a filtering position is replaced, dismounting and mounting are inconvenient, and the length of a filtering device cannot be adjusted are solved.

The application relates to the technical field of seawater desalination, and discloses a membrane method seawater desalination system capable of stably recycling concentrated water. The system comprises a first-stage two-section seawater reverse osmosis device, a first-stage two-section fresh water reverse osmosis device, an industrial water tank and a concentrated water discharge port. Raw seawater enters the seawater reverse osmosis device, the water produced by the seawater reverse osmosis device is connected to the industrial water tank and the fresh water reverse osmosis device in two ways, and the concentrated water is discharged and returned to the water inlet of the seawater reverse osmosis device in two ways; the water produced by the fresh water reverse osmosis device is connected to the industrial water tank, and the concentrated water is returned to the water inlet of the seawater reverse osmosis device. The system can adapt to wide-range water TDS fluctuation, simultaneously produce high-quality industrial water and concentrated water with stable concentration, improve water resource utilization rate and reduce operation cost.

The present invention relates to the technical field of helium separation, and specifically relates to a membrane method helium purification device, a purification system and a purification method, including: a purifier, and two separation tanks fixed on the side wall of the purifier, and the two separation tanks are connected to each other through a first delivery pipe; a rotating rod rotatably installed in the separation tank, an axially sliding clamping ring on the rotating rod, and a separation membrane fixed on the clamping ring; a trigger discharge mechanism arranged in the separation tank and connected to the rotating rod, used to drive the rotating rod to rotate when the pressure in the separation tank increases and discharge the residual gas; a pressurizing mechanism arranged in the separation tank, and a conduction impact mechanism is arranged on the pressurizing mechanism. Through the cooperation of the pressurizing mechanism and the conduction impact mechanism, a pressure difference can be formed on both sides of the separation membrane, and when the pressure reaches a set value, through the dual cooperation of air flow impact and bidirectional pressure, the effect of rapid purification of helium can be achieved.

The invention discloses a double-membrane seawater desalination and water regeneration device and method, and particularly relates to the field of water treatment.The double-membrane seawater desalination and water regeneration device comprises ultrafiltration units and reverse osmosis units, the ultrafiltration units are longitudinally arranged and communicated with the transversely arranged reverse osmosis units through bent pipes, and the water inlet ends of the ultrafiltration units are fixedly communicated with T-shaped pipes; a left side port of the T-shaped pipe is fixedly communicated with a water inlet pipe I through a flange, a right side port of the T-shaped pipe is fixedly communicated with a water inlet pipe II through a flange, and a switching valve is fixedly mounted on the T-shaped pipe. The T-shaped pipe can achieve independent water inlet or combined water inlet switching of the first water inlet pipe and the second water inlet pipe through the switching valve, seawater to be treated can be connected into the first water inlet pipe, regenerated water raw water can be connected into the second water inlet pipe, and independent treatment or mixed treatment of the two water sources is achieved by adjusting the opening degree of the switching valve. The double-working-condition operation requirements of seawater desalination and reclaimed water preparation are met; therefore, the effect of freely switching water inlet sources is achieved.

The utility model provides a membrane method deoxidation filter which comprises a body, a membrane method deoxidation filter core, a membrane method deoxidation filter core and a membrane method deoxidation filter core, the circulation pipe penetrates through the containing cavity, the circulation pipe is provided with a liquid inlet and a liquid outlet which are oppositely arranged, and a plurality of through holes are formed in the side wall of the circulation pipe and distributed at intervals in the extending direction of the circulation pipe; the filtering module is arranged in the containing cavity, the filtering module surrounds the periphery of the circulating pipe in the extending direction of the circulating pipe, the filtering cavity is provided with a gas channel, the gas channel communicates with the containing cavity, and the filtering module can filter oxygen in the fluid and enables the oxygen to flow into the containing cavity through the gas channel; the blocking part is arranged on the circulating pipe, the blocking part can separate the circulating pipe, and through holes are formed in the positions, on the two sides of the blocking part, of the circulating pipe. According to the technical scheme provided by the utility model, the problem that the boiler feed water deoxygenization effect is poor in the prior art can be solved.

This application relates to a seawater desalination system and method based on thermal-membrane coupling. The system includes a flue gas waste heat extraction device, a thermal desalination device, and a membrane desalination device; the flue gas waste heat extraction device is connected to both the thermal and membrane desalination devices; the flue gas waste heat extraction device is used to absorb the heat from the flue gas generated during the operation of the coal-fired power unit and generate a heat transfer medium adapted to the heat of the flue gas; the thermal desalination device is used to convert seawater entering the thermal desalination device into concentrated brine and primary freshwater using the heat transfer medium as the driving heat source; the membrane desalination device is used to desalinate the seawater entering the membrane desalination device to obtain secondary freshwater; the temperature of the concentrated brine is higher than that of the seawater entering the membrane desalination device; the seawater is preheated by the heat transfer medium and concentrated brine before entering the membrane desalination device, and the use of this system can improve the system energy efficiency.

The utility model belongs to the technical field of seawater treatment, and particularly relates to a filler mineralization filter tank for stabilizing desalted water, which comprises a filter tank body, a buffer area, a dissolved gas area, a filter area and a water and gas distribution area are sequentially arranged in the filter tank body from top to bottom, and an exhaust port and a water inlet are sequentially arranged in the buffer area of the filter tank body from top to bottom. A water outlet is formed in the water and gas distribution area of the filter tank body, the filter area is sequentially provided with a mineral substance layer, a supporting layer, a filter plate and a plurality of long-handle filter heads from top to bottom, the long-handle filter heads are transversely arranged, and a water distribution grating connected with the filter tank body through angle iron is arranged between the gas dissolving area and the water inlet; through grid flow equalization and filler diffusion, the full contact reaction of desalted water and mineralized filter materials is ensured, and the device has the characteristics of equipping, movability, diversification and the like, and is better suitable for reverse osmosis membrane method municipal water supply systems of various scales.

The utility model provides a kind of degassing structure based on constant low pressure and gas volume measurement, first, the liquid (for example transformer oil) to be degassed enters the degassing cavity inside the degassing chamber. The heating element arranged on the degassing chamber heats the liquid, increases the temperature of the liquid, thereby reduces the solubility of the dissolved gas therein, and promotes the release of the gas in free state. The characteristic gas released is rapidly circulated and uniformly distributed in the gas circuit by the air pump, and the gas circulation generates bubbles in the liquid, which can increase the gas-liquid contact area and further improve the degassing efficiency. The liquid is circulated in the oil circuit by the oil pump, which plays a role in stirring the liquid in the degassing chamber to improve the degassing efficiency. Through the comprehensive synergistic effect of heating, air extraction, bubbling and stirring, the problem of low degassing efficiency of traditional permeation membrane method is solved. The displacement amount of the piston in the cylinder can be used to reflect the gas volume entering the cylinder, and thus direct measurement of the volume of the released gas is realized.

The invention discloses an on-line osmotic cleaning forward osmosis-nanofiltration integrated membrane method seawater desalination method, which comprises: a, respectively feeding seawater and a draw solution into a raw material liquid side and a draw solution side of a forward osmosis system, feeding concentrated water into a raw material liquid tank, and feeding produced water into a draw solution tank; b, feeding the diluted draw solution into a nanofiltration system, feeding concentrated produced water on a concentrated water side into a concentrated water tank, and feeding produced water on a clear water side into a produced water tank; c, when the water production rate of the clear water side of the nanofiltration system is reduced to the set water production rate, closing the forward osmosis system and the nanofiltration system, and discharging the solution in the membrane component of the nanofiltration system; and d, feeding the concentrated water in the concentrated water tank as a cleaning solution into a permeation cleaning solution tank, feeding the cleaning solution in the permeation cleaning solution tank into the concentrated water side of the nanofiltration system, feeding the produced water in the produced water tank into the clear water side of the nanofiltration system, and carrying out online permeation cleaning on the nanofiltration membrane. According to the method disclosed by the invention, a mode of coupling a forward osmosis technology and a nanofiltration technology is adopted, so that low-energy-consumption seawater desalination is realized, and meanwhile, online cleaning of the nanofiltration membrane is realized.

The application discloses a system and method for recovering dichloroethane by VOCs membrane method, which comprises a water washing tower, a temporary storage tank, a condenser, a gas-liquid separator, an air draught fan, a membrane assembly and a storage tank; the gas inlet of the water washing tower is connected with the VOCs tail gas, and the gas outlet at the top of the water washing tower is connected with the gas inlet of the temporary storage tank; the gas outlet at the top of the temporary storage tank is connected with the gas inlet of the condenser, the gas outlet of the condenser is connected with the gas-liquid separator, and the liquid outlet at the bottom of the temporary storage tank and the gas-liquid separator is used for discharging the condensate; the gas outlet at the top of the gas-liquid separator is connected with the air draught fan, and the air draught fan is connected with the membrane assembly; the first outlet at the bottom of the membrane assembly is communicated with the storage tank, the storage tank is kept in vacuum negative pressure, the second outlet at the upper end of the membrane assembly is used for discharging the treated tail gas, and the system and method adopt the process of water washing pretreatment, deep cold pre-recovery and vacuum negative pressure membrane separation, a stable transmembrane pressure difference is built on both sides of the membrane through vacuum negative pressure, the mass transfer driving force of dichloroethane is greatly increased, the recovery efficiency is remarkably improved, and the product purity is high.

The present invention discloses a membrane seawater desalination system, comprising a first-stage reverse osmosis membrane array, a final-stage reverse osmosis membrane array, a fresh water collection container, a concentrated water collection container, and a plurality of electrically controlled switches. The first-stage reverse osmosis membrane array and the final-stage reverse osmosis membrane array both comprise a plurality of reverse osmosis membrane modules, which are arranged in a preset matrix manner. The output end of each reverse osmosis membrane module is respectively provided with a fresh water output pipe and a concentrated water output pipe, each of which is provided with an electrically controlled switch. By controlling the opening and closing of the electrically controlled switches, the reverse osmosis membrane modules can be connected in series or in parallel to meet the demand for rapid fresh water production according to the application scenario, and the fresh water collection container and the concentrated water collection container are provided to respectively collect the fresh water and concentrated water generated in the process of seawater desalination, thereby solving the technical problem that the existing membrane seawater desalination method is difficult to obtain high-purity fresh water and high seawater desalination efficiency according to actual production needs.

The application discloses a kind of online permeation cleaning forward osmosis-nanofiltration integrated membrane method seawater desalination method, comprising: a seawater, draw solution is respectively sent into the raw material liquid side and draw solution side of forward osmosis system, concentrated water is sent into raw material liquid tank, and product water is sent into draw solution tank;B after dilution draw solution is sent into nanofiltration system, concentrated water side after concentration product water is sent into concentrated water tank, and product water of clean water side is sent into product water tank;C when the product water rate of nanofiltration system clean water side drops to set product water rate, forward osmosis system and nanofiltration system are closed, and solution in nanofiltration system membrane assembly is discharged;D concentrated water in concentrated water tank is sent into permeation cleaning liquid tank as cleaning liquid, cleaning liquid in permeation cleaning liquid tank is sent into the concentrated water side of nanofiltration system, and product water in product water tank is sent into nanofiltration system clean water side, and nanofiltration membrane is carried out online permeation cleaning.The method of the application adopts the coupling mode of forward osmosis technology and nanofiltration technology, realizes low energy consumption seawater desalination, and realizes online cleaning of nanofiltration membrane simultaneously.