Direct contact type pervaporation membrane distillation separation device

Abstract

The invention discloses a direct contact type pervaporation membrane distillation separation device, which comprises a membrane pool, a membrane assembly, a vibrating membrane frame, a reciprocating driving mechanism, a bubbling unit, a shunting module, a confluence module, a liquid collection tank and an industrial personal computer, and the vibrating membrane frame is longitudinally and slidably arranged in the membrane pool and realizes front-back reciprocating motion. The bubbling unit comprises a bubbling machine, a high-pressure air pipe I and a high-pressure air pipe II, an aeration disc is arranged on the high-pressure air pipe I, and a micro-nano aeration head is arranged on the high-pressure air pipe II. Cavities are formed in the membrane assemblies, all the membrane assemblies located at the same position are vertically and sequentially connected in series, and a low-temperature fluid medium sequentially passes through the flow dividing module, the cavities of all the membrane assemblies and the flow dividing module to reach the liquid collecting tank. Vibration and bubbling are combined, so that the flux of the membrane is increased while energy consumption is reduced, turbulent flow and shear flow are formed on the surface of the membrane, pollution to the surface of the membrane is reduced, and the service life of the membrane is prolonged.

Description

Technical Field

[0001] This invention relates to the field of pervaporation membrane distillation technology, and more specifically to a direct contact pervaporation membrane distillation separation device. Background Technology

[0002] Separation processes in the petrochemical industry are among the most energy-intensive, with separation equipment accounting for approximately 70% of total energy consumption. This process is extremely energy-intensive. Membrane separation technology offers unique advantages over other separation technologies, namely high efficiency and low energy consumption. Therefore, there is an urgent need to create new equipment based on membrane separation technology to meet the difficult and extreme separation requirements of the petrochemical industry. For example, existing membrane separation equipment used in the petrochemical industry for high-salt wastewater, organic solvent dehydration, and organic solvent-to-organic solvent separation struggles to achieve high packing density and high temperature tolerance. Furthermore, most current membrane separation equipment passively improves membrane life by controlling liquid flow rate. Therefore, there is an urgent need to design new membrane separation equipment specifically for high-salt wastewater, organic solvent dehydration, and organic solvent-to-organic solvent separation in the petrochemical industry. This equipment should simultaneously possess high packing density with unlimited scalability, high temperature tolerance, and an active multi-system approach to synergistically improve membrane life. In summary, the above factors are key influencing factors for the industrialization of petrochemical processes. Summary of the Invention

[0003] To address the shortcomings of the existing technologies, the present invention aims to propose a direct contact pervaporation membrane distillation separation device to solve the problems of difficult-to-treat high-salt wastewater, organic solvent dehydration, and membrane separation of organic solvents in the petrochemical industry, as well as low membrane packing density, easy and uncontrollable membrane fouling, and short service life.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0005] A direct contact pervaporation membrane distillation separation device includes a membrane tank, a membrane module, a vibrating membrane frame, a reciprocating drive mechanism, a bubbling unit, a diversion module, a confluence module, a liquid collection tank, a cleaning system, and an industrial control computer. The vibrating membrane frame is longitudinally slidably disposed in the membrane tank, and the reciprocating drive mechanism is disposed above the membrane tank to drive the vibrating membrane frame to reciprocate back and forth.

[0006] The vibrating membrane frame is provided with at least one layer of membrane components. Each layer of membrane components includes multiple membrane components arranged sequentially from left to right. When the number of membrane components is greater than 1, the membrane components are stacked sequentially from bottom to top. Each membrane component is vertically arranged and its upper and lower ends are fixedly connected to the vibrating membrane frame. Each membrane component in the upper layer is vertically aligned with each membrane component in the adjacent lower layer.

[0007] The membrane module has an internal cavity, and the bottom and top of the membrane module are respectively provided with an inlet end and an outlet end. Membrane modules at the same position are connected in series vertically.

[0008] The diversion module is located at the bottom of the membrane tank. The inlet of the diversion module is connected to a third pipe. In operation, the low-temperature fluid medium is supplied to the inside of the diversion module through the third pipe.

[0009] The manifold module is located above the membrane tank. The diversion module is connected to the manifold module through all membrane components and is in communication with it. The outlet of the manifold module is connected to the top of the liquid collection tank through the fourth pipe. A delivery pump is installed on the third pipe, and the signal end of the delivery pump is connected to the industrial control computer for communication.

[0010] The bubbling unit includes a bubbler and two high-pressure air pipes located below the membrane module. The bubbler is equipped with a first servo motor connected to an industrial control computer. At least two high-pressure air pipes are provided for each of the two units, fixedly installed at the bottom of the membrane tank. The exhaust end of the bubbler supplies air independently to both high-pressure air pipes via a three-way valve. Multiple aeration discs are mounted on high-pressure air pipe 1, and multiple micro / nano aeration heads are mounted on high-pressure air pipe 2. By controlling the airflow and the aeration components (aeration discs and micro / nano aeration heads), the bubbling volume and bubble size can be synergistically adjusted from micro / nano to micro / millimeter levels.

[0011] The lower part of the membrane tank is equipped with an online liquid concentration monitor, the signal end of which is connected to the industrial control computer.

[0012] Furthermore, the membrane assembly includes a membrane body and a square rigid frame. The rigid frame is arranged vertically and is open on both sides. There are two membrane bodies, both of which are flat membranes. The two membrane bodies are symmetrically arranged on both sides of the rigid frame. The edges of the two membrane bodies are fixedly and sealed to the corresponding sides of the rigid frame to form the internal cavity of the membrane assembly.

[0013] The inlet end of the membrane module is located at the bottom of the rigid frame, and its outlet end is located at the top of the rigid frame. The inlet and outlet ends of two vertically adjacent rigid frames are connected by pipelines.

[0014] Furthermore, the membrane assembly includes an upper box, a lower box, and a membrane body. Both the upper and lower boxes are longitudinally arranged elongated shells, and are arranged parallel to each other on the vibrating membrane frame, one higher and one lower. The upper and lower boxes are detachably and fixedly connected to the vibrating membrane frame.

[0015] The membrane body consists of several regularly distributed hollow fiber membranes, each arranged vertically. Its upper end is fixedly and sealed to the upper box body through an upper mounting base, and its lower end is fixedly and sealed to the lower box body through a lower mounting base. The interior of the upper box body is connected to the interior of the lower box body through the inner cavity of the hollow fiber membrane.

[0016] The inlet end of the membrane module is located at the bottom of the lower housing, and its outlet end is located at the top of the upper housing. The upper and lower housings of two vertically adjacent membrane modules are connected by pipelines.

[0017] Furthermore, the vibrating diaphragm frame is a square three-dimensional frame structure, and the inner side of the vibrating diaphragm frame has a positioning mechanism that is equal in number and corresponds one-to-one with the positions of the diaphragm components.

[0018] The positioning mechanism includes two pairs of mounting plates arranged vertically and vertically, both pairs of mounting plates are fixed to the vibrating membrane frame, and a U-shaped groove is formed between each pair of mounting plates to place the membrane module.

[0019] Each U-shaped groove has a long strip-shaped positioning plate inside. The positioning plate is connected to the mounting plate on its adjacent side by a set of locking bolts arranged longitudinally at intervals, fixing the upper and lower ends of the membrane module between the two pairs of mounting plates.

[0020] Furthermore, a cover is provided above the membrane tank, and the bottom edge of the cover is detachably and fixedly sealed to the top of the membrane tank, with the vibrating membrane frame located below the cover.

[0021] Two connecting frames are symmetrically arranged on the left and right sides of the vibrating membrane frame. Two guide rails are arranged in parallel at intervals above the membrane pool. The upper ends of the two connecting frames are longitudinally slidably engaged with the two guide rails respectively, and the lower ends pass through the cover and are fixedly connected to the upper end of the vibrating membrane frame. The connecting frames and the cover are movably sealed together.

[0022] The reciprocating drive mechanism includes a second servo motor, a crank, a connecting rod, and a slider bearing housing. One end of the crank is fixedly connected to the output shaft of the second servo motor. The slider bearing housing is sleeved on the outside of the crank and slides linearly with it. The side wall of the crank has multiple bolt holes distributed along its length. The slider bearing housing is provided with positioning bolts. One end of the connecting rod is hinged to the slider bearing housing, and the other end of the connecting rod is hinged to one of the connecting frames.

[0023] Furthermore, all high-pressure air pipes are arranged in parallel at intervals, and the aeration discs on the same high-pressure air pipe are arranged at equal intervals along their length. All high-pressure air pipes are also arranged in parallel at intervals, and the micro-nano aeration heads on the same high-pressure air pipe are arranged at equal intervals along their length.

[0024] The exhaust end of the bubble machine is connected to the inlet end of the three-way valve through the first pipe body. The three-way valve has two outlet ends. Each high-pressure air pipe one is connected to one outlet end of the three-way valve through the second pipe body, and each high-pressure air pipe two is connected to the other outlet end of the three-way valve through the same second pipe body. A first shut-off valve is provided on the second pipe body.

[0025] An electromagnetic flowmeter is installed on the first pipe body, and the signal terminal of the electromagnetic flowmeter is connected to the industrial control computer for communication.

[0026] Furthermore, the diversion module and the junction module are installed at the bottom and top of the vibrating membrane frame, respectively. The top of the diversion module has an outlet end that is equal in number and position to each membrane module. Each outlet end of the diversion module is connected to the inlet end of the corresponding membrane module at the bottom layer through a fifth tube.

[0027] The bottom of the manifold module has an inlet end that is equal in number and one-to-one with the position of each membrane module. Each inlet end of the manifold module is connected to the outlet end of the corresponding membrane module in the uppermost layer through a sixth tube. The manifold module is equipped with an online liquid concentration monitor II. The signal end of the online liquid concentration monitor II is connected to the industrial control computer for communication.

[0028] Furthermore, it also includes a heat exchanger and a low-temperature cold source, which are connected to the shell-side inlet and outlet pipes of the heat exchanger to form a cold water circulation loop.

[0029] The liquid collection tank is equipped with an electronic level gauge inside, and a drain pipe is connected to its bottom. A first shut-off valve is installed on the drain pipe. The signal terminals of the electronic level gauge and the first shut-off valve are connected to the industrial control computer. The lower side of the liquid collection tank is connected to the tube inlet of the heat exchanger through the seventh tube. The tube inlet of the heat exchanger is connected to the end of the third tube away from the diversion module.

[0030] Furthermore, it also includes an evaporator crystallizer equipped with a stirring mechanism. The evaporator crystallizer is arranged outside the membrane tank and adopts a sealed shell with a heating function at the bottom. The inlet of the evaporator crystallizer is connected to the outlet at the bottom of the membrane tank through an eighth pipe. A second shut-off valve is provided on the eighth pipe. A pressure relief valve is provided on the top of the evaporator crystallizer.

[0031] The stirring mechanism includes stirring blades, a drive shaft, and a third servo motor. The third servo motor is installed above the evaporator crystallizer, and the stirring blades are located on the lower inner side of the evaporator crystallizer. The stirring blades are fixedly connected to the output shaft of the third servo motor through the drive shaft.

[0032] Furthermore, the cleaning system includes a water pump and a main cleaning pipe. The water pump is located at one end of the main cleaning pipe, and the main cleaning pipe is equipped with cleaning branch pipes that are equal in number and corresponding in position to the membrane modules. The lower end of each cleaning branch pipe is located on the adjacent side of the corresponding membrane module, and its upper end is connected to the main cleaning pipe.

[0033] The main cleaning pipe is equipped with an electromagnetic gate valve, and the signal terminal of the electromagnetic gate valve is connected to the industrial control computer.

[0034] By adopting the above technical solution, the beneficial technical effects of the present invention are as follows: The membrane module of the present invention combines horizontal reciprocating vibration with a large number of microbubbles to increase the water vapor flux by increasing the flow velocity on the membrane surface, thereby improving the membrane separation performance and ensuring faster collection of pure water. In addition, the vertical movement of the bubbles and the horizontal movement of the membrane facilitate the formation of turbulent and shear flow on the membrane surface, which can effectively reduce the accumulation of pollutants on the membrane surface and thus reduce membrane fouling. Furthermore, by controlling the vacuum level and the concentration polarization of the membrane surface in a coordinated manner through bubbling and vibration, the membrane's resistance to organic fouling and inorganic salt scaling is further improved, thereby increasing the membrane's service life. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the first implementation of a direct contact pervaporation membrane distillation separation device according to the present invention.

[0036] Figure 2 This is a schematic diagram of the combined structure of the vibrating diaphragm frame and the reciprocating drive mechanism of the present invention.

[0037] Figure 3 yes Figure 2 A magnified view of part A in the middle.

[0038] Figure 4 yes Figure 2 A magnified view of part B in the middle section.

[0039] Figure 5 This is a schematic diagram of a second implementation of the direct contact pervaporation membrane distillation separation device of the present invention.

[0040] Figure 6 This is a schematic diagram of a third implementation of the direct contact pervaporation membrane distillation separation device of the present invention.

[0041] Figure 7 This is a schematic diagram of the fourth implementation of the direct contact pervaporation membrane distillation separation device of the present invention. Detailed Implementation

[0042] The present invention will now be described in detail with reference to the accompanying drawings:

[0043] Example 1, combined with Figures 1 to 4 A direct contact pervaporation membrane distillation separation device is mainly used in the fields of high-salt wastewater treatment, organic solvent dehydration, and separation between organic solvents. It is particularly suitable for pervaporation membranes and membrane distillation membranes. The driving force of the pervaporation membrane and distillation membrane is mainly temperature difference. The temperature difference on both sides of the membrane body is different, which leads to the difference in vapor pressure between the feed liquid group and the inner side of the membrane body. This causes volatile substances and substances with strong interaction with the membrane to preferentially reach the other side of the membrane, thereby achieving the purpose of separation, purification and concentration.

[0044] A direct contact pervaporation membrane distillation separation device includes a membrane tank 1, a membrane module 2, a vibrating membrane frame 3, a reciprocating drive mechanism 4, a bubbling unit, a diversion module 61, a confluence module 62, a liquid collection tank 7, a cleaning system, and an industrial control computer. The top of the membrane tank 1 is equipped with a cover. The raw material liquid is injected into the interior of the membrane tank 1 through a pipe. The treated raw material liquid can be discharged to the outside through the outlet at the bottom of the membrane tank 1.

[0045] The vibrating diaphragm frame 3 is a square or rectangular frame structure. The vibrating diaphragm frame 3 is longitudinally slidably disposed within the membrane tank 1. The reciprocating drive mechanism 4 is disposed above the membrane tank 1, driving the vibrating diaphragm frame 3 to reciprocate back and forth. A cover is disposed above the membrane tank 1, and the bottom edge of the cover is detachably and securely connected to the top of the membrane tank 1. The vibrating diaphragm frame 3 is located below the cover.

[0046] The vibrating membrane frame 3 has two connecting frames 33 symmetrically arranged on the left and right sides. There are two parallel guide rails 34 arranged at intervals above the membrane pool. The upper ends of the two connecting frames 33 are respectively longitudinally slidingly engaged with the two guide rails 34. The lower ends of the two connecting frames 33 pass through the cover and are fixedly connected to the upper end of the vibrating membrane frame 3. The connecting frames 33 and the cover are in a movable sealing engagement.

[0047] Specifically, the connecting frame 33 includes two vertically spaced uprights. The cover has elongated holes that are equal in number and correspond one-to-one with the number of uprights. Each upright is vertically inserted into the inner side of the corresponding elongated hole. Each upright is fitted with a flared rubber sealing sleeve. The closed end of the rubber sealing sleeve is fixedly and sealed to the outer wall of the upright. The flared end of the rubber sealing sleeve covers the corresponding elongated hole and is fixedly and sealed to the upper surface of the cover. During the back-and-forth movement of the connecting frame 33 relative to the cover, the airtightness of the membrane pool 1 is ensured.

[0048] The reciprocating drive mechanism 4 includes a second servo motor 41, a crank 42, a connecting rod 43, and a slider bearing seat 44. One end of the crank 42 is fixedly connected to the output shaft of the second servo motor 41. The slider bearing seat 44 is sleeved on the outside of the crank 42 and slides linearly with it. The side wall of the crank 42 has multiple bolt holes 45 distributed along its length. The slider bearing seat 42 is provided with positioning bolts 46. One end of the connecting rod 43 is hinged to the slider bearing seat 44, and the other end of the connecting rod 43 is hinged to one of the connecting frames 33. After the positioning bolts 46 release the lock on the slider bearing seat 44, the slider bearing seat 44 can slide along the length of the crank 42, changing its position on the crank 42, thereby adjusting the amplitude of the vibrating diaphragm 3 to meet the requirements of different processes. The signal terminal of the second servo motor 41 is connected to the industrial control computer for communication. The industrial control computer controls the rotation speed of the second servo motor 41 through commands, thereby controlling and adjusting the reciprocating vibration frequency of the vibrating diaphragm 3. The appropriate vibration frequency and amplitude are selected according to the raw material liquid being processed. The vibration frequency of the vibrating diaphragm 3 is 0.5Hz to 150Hz. The amplitude of the vibrating diaphragm 3 is adjusted by adjusting the position of the slider bearing seat 42 on the crank 42. The amplitude adjustment range is 0.2cm to 100cm.

[0049] When a membrane assembly 2 is provided inside the vibrating membrane frame 3, the membrane assembly 2 is arranged as a whole in a flat manner, and each membrane assembly 2 includes multiple membrane assemblies 2 arranged alternately from left to right. When at least two membrane assemblies 2 are provided inside the vibrating membrane frame 3, the membrane assemblies 2 are arranged in alternating layers from bottom to top, and each membrane assembly 2 in each layer is vertically arranged, with its upper and lower ends fixedly connected to the vibrating membrane frame 3. Each membrane assembly 2 in the upper layer is vertically aligned with each membrane assembly 2 in the adjacent lower layer.

[0050] The membrane module 2 has an internal cavity. The bottom and top of the membrane module 2 are respectively provided with an inlet and an outlet. Membrane modules at the same position are vertically connected in series. A diversion module 61 is located at the lower part of the membrane tank 1. The inlet of the diversion module 61 is connected to a third pipe 63. The diversion module 61 is connected to a cryogenic fluid medium through the third pipe 63. A transfer pump 631 is installed on the third pipe 63, and the signal terminal of the transfer pump 631 is connected to an industrial control computer. A manifold module 62 is located above the membrane tank 1. The diversion module 61 is connected to and communicates with the manifold module 62 through the internal cavities of all membrane modules 2. The outlet of the manifold module is connected to the top of the liquid collection tank 7 through a fourth pipe 64.

[0051] Specifically, the membrane module 2 includes a membrane body 22 and a square rigid frame 21. The rigid frame 21 is vertically arranged and extends through both sides. There are two membrane bodies 22, both of which use flat sheet membranes, such as microfiltration membranes, nanofiltration membranes, dense membranes, or Janus structure membranes. The type of flat sheet membrane used is determined according to the feed liquid being treated and the process requirements. The two membrane bodies 22 are symmetrically arranged on both sides of the rigid frame 21, and the edges of the two membrane bodies 22 are fixedly and sealed to the corresponding sides of the rigid frame 21, forming the internal cavity of the membrane module 2. The inlet end of the membrane module 2 is located at the bottom of the rigid frame 21, and its outlet end is located at the top of the rigid frame 21. The inlet and outlet ends of two vertically adjacent rigid frames 21 are connected by pipelines, so that the cavities of each membrane module 2 at the same vertical position are interconnected.

[0052] The diversion module 61 and the junction module 62 are fixedly installed at the bottom and top of the vibrating membrane frame 3, respectively. The top of the diversion module 61 has an outlet end that corresponds to the number and position of each membrane assembly 2. Each outlet end of the diversion module 61 is connected to the inlet end of the corresponding membrane assembly 2 in the bottom layer through a fifth tube 65. The bottom of the junction module 62 has an inlet end that corresponds to the number and position of each membrane assembly 2 in the bottom layer. Each inlet end of the junction module 62 is connected to the outlet end of the corresponding membrane assembly 2 in the top layer through a sixth tube 66. The third tube 63 and the fourth tube 64 both have flexible sections.

[0053] The manifold module 62 is located above the cover. The sixth tube 66 is a two-section flexible tube, with the two parts connected by a rigid joint. The rigid joint is embedded in the cover and seals against it. One part of the sixth tube 66 is located below the cover, and the other part is located above the cover. The cover seals the interior of the membrane tank 1. In operation, the feed liquid inside the membrane tank 1 is under a set pressure. Under a certain pressure, the feed liquid can improve the membrane flux and separation efficiency.

[0054] The manifold module 62 is equipped with an online liquid concentration monitor 2. The signal terminal of the online liquid concentration monitor 2 is connected to the industrial control computer. The online liquid concentration monitor 2 monitors the concentration value of the liquid inside the manifold module 62 in real time and sends the concentration value to the industrial control computer as one of the important indicators for analyzing the operating status of the entire separation device.

[0055] In operation, a cryogenic fluid medium is supplied to the inside of the diversion module 61 through the third pipe 63. The cryogenic fluid medium enters the cavity of the lowest membrane module 2 through the diversion module 61, passes through the cavities of the membrane modules 2 connected in series with it, and collects into the inside of the manifold module 62. It then passes through the fourth pipe 64 and reaches the inside of the liquid collection tank 7 for collection. When the cryogenic fluid medium passes through the cavity of the membrane module 2, the internal cavity pressure of the membrane module 2 is lower than its external pressure. Under the action of the pressure difference, the water vapor in the high-salt wastewater can quickly pass through the membrane body 22 and enter the internal cavity of the membrane module 2. The water vapor entering the membrane module 2 undergoes heat exchange with the cryogenic fluid medium flowing through the membrane module 2 and becomes condensate. It mixes with the cryogenic fluid medium and enters the liquid collection tank 7. It should be emphasized that when separating the high-salt wastewater in the membrane tank 1 and dehydrating the organic solvent, the cryogenic fluid medium used is cryogenic pure water; when separating organic solvents in the membrane tank 1, the cryogenic fluid medium used is the same cryogenic organic solvent as the organic solvent to be separated, that is, the cryogenic fluid medium and the organic solvent to be separated are the same substance.

[0056] The inner side of the vibrating membrane frame 3 has a positioning mechanism that is equal in number and corresponds one-to-one with the membrane assembly 2. All positioning mechanisms are arranged in sequence from left to right. Specifically, the positioning mechanism includes two pairs of mounting plates 31 arranged vertically and vertically. Both pairs of mounting plates 31 are fixedly mounted on the vibrating membrane frame 3. A U-shaped groove for placing the membrane assembly 2 is formed between each pair of mounting plates 31.

[0057] Each U-shaped groove has a long strip-shaped positioning plate 32 inside. The positioning plate 32 is connected to the mounting plate 31 on its adjacent side by a set of locking bolts 321 arranged longitudinally at intervals. Each set of locking bolts 321 includes multiple locking bolts 321 arranged longitudinally at intervals and screwed onto the mounting plate 31. The positioning plate 32 fixes the upper and lower ends of the membrane assembly 2 between the two pairs of mounting plates 31. The rigid frame 21 of membrane module 2 is placed between two pairs of mounting plates 31 at its upper and lower ends. By tightening the locking bolts 321, the positioning plates 32 fix the upper and lower ends of the rigid frame 21 into the vibrating membrane frame 3. The vibrating membrane frame 3 drives all membrane modules 2 to vibrate longitudinally and horizontally. The surfaces of all planar membranes reciprocate back and forth relative to the feed liquid. Firstly, this increases the flow velocity on the membrane surface, resulting in a larger vapor pressure on the membrane surface, which in turn increases the vapor pressure difference between the inside and outside of the membrane, thereby increasing the water vapor flux and improving the membrane separation performance. Secondly, the back-and-forth vibration of the membrane surface interacts with the rising bubbles, which helps to form turbulence on the membrane surface. This turbulence can effectively reduce the accumulation of pollutants on the membrane surface, thereby reducing membrane fouling.

[0058] The bubbling unit includes a bubbler 51 and two high-pressure air pipes 58 and 52 located below the membrane module 2. The bubbler 51 is equipped with a first servo motor connected to the industrial control computer. The function of the bubbler 51 is to generate high-pressure air. Two high-pressure air pipes 58 and 52 are provided, and the two high-pressure air pipes 52 are fixedly installed parallel to each other at the bottom of the membrane tank 1. Two high-pressure air pipes 58 are fixedly installed parallel to each other at the bottom of the membrane tank 1, located between the two high-pressure air pipes 52. Aeration discs 581 located on the same high-pressure air pipe 58 are arranged at equal intervals along its length. The aeration discs 581 are located at the top of the high-pressure air pipe 58, and their bottom air inlet ends are connected to the high-pressure air pipe 58. A one-way valve is provided at the connection between the aeration disc 581 and the high-pressure air pipe 58.

[0059] Specifically, the second high-pressure air pipe 52 has micro-nano aeration heads 57 evenly spaced along its length. Each micro-nano aeration head 57 is equipped with a water pump. The second high-pressure air pipe 52 is connected to the air inlet of the micro-nano aeration head 57, and the water outlets of the micro-nano aeration heads 57 on the two second high-pressure air pipes 52 are arranged opposite to each other. The exhaust end of the bubbler is controlled by a three-way valve 54 to independently control the air supply to the first high-pressure air pipe 58 and the second high-pressure air pipe 52. The first high-pressure air pipe 58 and the second high-pressure air pipe 52 operate independently. Specifically, the exhaust end of the bubbler 51 is connected to the air inlet of the three-way valve 54 through the first pipe body 53. The three-way valve 54 has two air outlets. Each first high-pressure air pipe 58 is connected to one air outlet of the three-way valve 54 through the second pipe body 55, and each second high-pressure air pipe 52 is connected to the other air outlet of the three-way valve 54 through the same second pipe body 55. The second pipe body 55 is equipped with a first shut-off valve 59.

[0060] When the aeration disc 581 provides aeration to the membrane tank 1, the compressed air generated by the bubbler 51 enters the high-pressure air pipe 58 through the three-way valve 54 and is discharged through the upper surface of the aeration disc 581, continuously forming uniform large bubbles in the membrane tank 1, and moving rapidly from bottom to top to the surface of the raw material liquid, forming a shear flow in an inclined direction with the back and forth movement of the flat membrane. It should be noted that the large bubbles referred to here are relative to nanobubbles.

[0061] In addition, when the micro-nano aeration head 57 provides aeration to the membrane tank 1, the high-pressure air entering the high-pressure air pipe 52 is discharged through the micro-nano aeration head 57, continuously forming uniform nanobubbles in the membrane tank 1. These bubbles move rapidly from bottom to top to the surface of the feed liquid, forming a shear flow in an inclined direction with the back-and-forth movement of the flat sheet membrane. An electromagnetic flowmeter 56 is installed on the first pipe body 53. The signal end of the electromagnetic flowmeter 56 is connected to the industrial control computer. The electromagnetic flowmeter 56 monitors the flow rate of the high-pressure air entering the high-pressure air pipe 52 and adjusts the aeration rate. The bubble volume per unit time and area can be quantified as the ratio of aeration volume to effluent of 4 to 50:1. This device provides the above two aeration modes for the membrane tank 1. The appropriate aeration method can be selected according to the feed liquid being treated and the process requirements.

[0062] This embodiment improves the membrane's resistance to inorganic salts and organic fouling by controlling the size and quantity of bubbles and coordinating with the vibration system. Vibration and bubbling increase the flow velocity on the membrane surface, thereby increasing water vapor flux. Furthermore, intelligent control of vacuum level and coordinated control of bubbling and vibration to regulate concentration polarization on the membrane surface further enhances the membrane's resistance to organic fouling or inorganic salt scaling. Finally, through the coordinated control of these three aspects, the membrane lifespan can be greatly extended and operating energy consumption reduced, thereby ensuring a highly efficient pervaporation process and improving the quality and efficiency of membrane pervaporation.

[0063] The direct contact pervaporation membrane distillation separation device also includes a heat exchanger 67 and a low-temperature cold source. The low-temperature cold source is connected to the shell-side inlet and outlet pipes of the heat exchanger 67 to form a cold water circulation loop. The liquid collection tank 7 is equipped with an electronic level gauge inside, and a drain pipe 71 is connected to its bottom. A first shut-off valve 72 is installed on the drain pipe. The signal terminals of the electronic level gauge and the first shut-off valve 72 are connected to the industrial control computer. The lower side of the liquid collection tank 7 is connected to the tube-side inlet of the heat exchanger 67 through a seventh tube 73. The tube-side inlet of the heat exchanger 67 is connected to the end of the third tube 63 away from the diversion module 61.

[0064] When dehydrating high-salt wastewater or organic solvents, the cryogenic fluid medium is cryogenic purified water, and the water collected in liquid collection tank 7 is also purified water, with a higher temperature than the purified water in the diversion module 61. Similarly, when separating organic solvents, the cryogenic fluid medium is the same cryogenic organic solvent as the organic solvent to be separated. The organic solvent separated from the membrane tank 1 is called the target organic solvent, and the organic solvent collected in liquid collection tank 7 has a higher temperature. When the liquid in liquid collection tank 7 (distilled water or target organic solvent) needs to be used as the fluid medium, part of the organic solvent in liquid collection tank 7 needs to be cooled. Specifically, part of the liquid in liquid collection tank 7 enters the heat exchanger 67 through the seventh tube 73 for cooling to obtain a cryogenic fluid medium. Then, it is pumped to the diversion module 61 through the third tube 63 and returns to the liquid collection tank 7 in the same way, ensuring a continuous supply of cryogenic fluid medium to the interior of all membrane modules 2. The electronic level gauge monitors the liquid level in liquid collection tank 7 in real time and periodically discharges excess liquid from liquid collection tank 7.

[0065] An online liquid concentration monitor 11 is installed at the lower part of the membrane tank 1. The signal terminal of the online liquid concentration monitor 11 is connected to the industrial control computer. The online liquid concentration monitor 11 monitors the concentration of the feed liquid in the membrane tank 1 in real time. In operation, the concentration of the feed liquid in the membrane tank 1 increases as evaporation proceeds. When the concentration of the feed liquid reaches a set threshold, new feed liquid is added to the membrane tank 1. After the feed liquid in the membrane tank 1 mixes with the newly added feed liquid, the concentration decreases, and separation continues through the membrane module 2.

[0066] When used for high-salt wastewater separation or organic solvent dehydration, the water vapor filtered through the membrane module enters the membrane module in the form of steam and undergoes heat exchange. The steam cools in the cooling chamber 201 of the membrane module, forming condensate, which flows through the drain pipe 73 into the collection tank 7, ultimately being produced as pure liquid water. Taking the application of a nanofiltration membrane (22) in the distillation separation of magnesium-lithium salt solutions as an example, the molecular weight cutoff is between that of reverse osmosis and ultrafiltration membranes, approximately 100–2000 Da. This suggests that the nanofiltration membrane may have a microporous structure with a pore size of approximately 1–5 nm. Applications include magnesium-lithium salt solution separation, removal of organic matter and color from surface water, removal of hardness from groundwater, partial removal of dissolved salts, concentration of fruit juice, and separation of useful substances from pharmaceuticals. The main separation mechanisms include pore size sieving and the synergistic effect of Dornan repulsion, with Dornan repulsion's intramembrane charge repulsion being the dominant mechanism.

[0067] The cleaning system includes a water pump 81 and a main cleaning pipe 82. The water pump 81 is located at one end of the main cleaning pipe 82. The main cleaning pipe 82 has cleaning branch pipes 83, which are equal in number and corresponding in position to the membrane modules 2. The lower end of each cleaning branch pipe 83 can be connected to the upper end of the corresponding air guide pipe 72, and its upper end is connected to the main cleaning pipe 82. The main cleaning pipe 82 is equipped with an electromagnetic gate valve 84, and the signal terminal of the electromagnetic gate valve 84 is connected to the industrial control computer. In the working state, the electromagnetic gate valve 84 is in the closed state. After running for a certain period of time, it is necessary to clean the dirt on the membrane surface. The cleaning system uses a special cleaning agent to backwash the flat membranes on both sides of each membrane module 2 through the cleaning branch pipes 83 into the cooling chamber 202 of each membrane module 2, removing dirt and impurities from the membrane surface.

[0068] Example 2, combined with Figures 2 to 5 A direct contact pervaporation membrane distillation separation device is mainly used in the fields of high-salt wastewater treatment, organic solvent dehydration and separation between organic solvents, and is especially suitable for pervaporation membranes and membrane distillation membranes.

[0069] A direct contact pervaporation membrane distillation separation device includes a membrane tank 1, a membrane module 2, a vibrating membrane frame 3, a reciprocating drive mechanism 4, a bubbling unit, a diversion module 61, a confluence module 62, a liquid collection tank 7, a cleaning system, and an industrial control computer. The top of the membrane tank 1 is equipped with a cover. The raw material liquid is injected into the interior of the membrane tank 1 through a pipe. The treated raw material liquid can be discharged to the outside through the outlet at the bottom of the membrane tank 1.

[0070] The vibrating diaphragm frame 3 is a square or rectangular frame structure. The vibrating diaphragm frame 3 is longitudinally slidably disposed within the membrane tank 1. The reciprocating drive mechanism 4 is disposed above the membrane tank 1, driving the vibrating diaphragm frame 3 to reciprocate back and forth. A cover is disposed above the membrane tank 1, and the bottom edge of the cover is detachably and securely connected to the top of the membrane tank 1. The vibrating diaphragm frame 3 is located below the cover.

[0071] The vibrating membrane frame 3 has two connecting frames 33 symmetrically arranged on the left and right sides. There are two parallel guide rails 34 arranged at intervals above the membrane pool. The upper ends of the two connecting frames 33 are respectively longitudinally slidingly engaged with the two guide rails 34. The lower ends of the two connecting frames 33 pass through the cover and are fixedly connected to the upper end of the vibrating membrane frame 3. The connecting frames 33 and the cover are in a movable sealing engagement.

[0072] Specifically, the connecting frame 33 includes two vertically spaced uprights. The cover has elongated holes that are equal in number and correspond one-to-one with the number of uprights. Each upright is vertically inserted into the inner side of the corresponding elongated hole. Each upright is fitted with a flared rubber sealing sleeve. The closed end of the rubber sealing sleeve is fixedly and sealed to the outer wall of the upright. The flared end of the rubber sealing sleeve covers the corresponding elongated hole and is fixedly and sealed to the upper surface of the cover. During the back-and-forth movement of the connecting frame 33 relative to the cover, the airtightness of the membrane pool 1 is ensured.

[0073] The reciprocating drive mechanism 4 includes a second servo motor 41, a crank 42, a connecting rod 43, and a slider bearing seat 44. One end of the crank 42 is fixedly connected to the output shaft of the second servo motor 41. The slider bearing seat 44 is sleeved on the outside of the crank 42 and slides linearly with it. The side wall of the crank 42 has multiple bolt holes 45 distributed along its length. The slider bearing seat 42 is provided with positioning bolts 46. One end of the connecting rod 43 is hinged to the slider bearing seat 44, and the other end of the connecting rod 43 is hinged to one of the connecting frames 33. After the positioning bolts 46 release the lock on the slider bearing seat 44, the slider bearing seat 44 can slide along the length of the crank 42, changing its position on the crank 42, thereby adjusting the amplitude of the vibrating diaphragm 3 to meet the requirements of different processes.

[0074] The signal terminal of the second servo motor 41 is connected to the industrial control computer for communication. The industrial control computer controls the rotation speed of the second servo motor 41 through commands, thereby controlling and adjusting the reciprocating vibration frequency of the vibrating diaphragm 3. The appropriate vibration frequency and amplitude are selected according to the raw material liquid being processed. The vibration frequency of the vibrating diaphragm 3 is 0.5Hz to 150Hz. The amplitude of the vibrating diaphragm 3 is adjusted by adjusting the position of the slider bearing seat 42 on the crank 42. The amplitude adjustment range is 0.2cm to 100cm.

[0075] When a membrane assembly 2 is provided inside the vibrating membrane frame 3, the membrane assembly 2 is arranged as a whole in a flat manner, and each membrane assembly 2 includes multiple membrane assemblies 2 arranged alternately from left to right. When at least two membrane assemblies 2 are provided inside the vibrating membrane frame 3, the membrane assemblies 2 are arranged alternately from bottom to top, and each membrane assembly 2 in each layer is vertically arranged, with its upper and lower ends fixedly connected to the vibrating membrane frame 3. Each membrane assembly 2 in the upper layer is vertically aligned with each membrane assembly 2 in the adjacent lower layer.

[0076] The membrane module 2 has an internal cavity. The bottom and top of the membrane module 2 are respectively provided with an inlet and an outlet. Membrane modules at the same position are vertically connected in series. A diversion module 61 is located at the lower part of the membrane tank 1. The inlet of the diversion module 61 is connected to a third pipe 63. The diversion module 61 is connected to a cryogenic fluid medium through the third pipe 63. A transfer pump 631 is installed on the third pipe 63, and the signal terminal of the transfer pump 631 is connected to an industrial control computer. A manifold module 62 is located above the membrane tank 1. The diversion module 61 is connected to and communicates with the manifold module 62 through the internal cavities of all membrane modules 2. The outlet of the manifold module is connected to the top of the liquid collection tank 7 through a fourth pipe 64.

[0077] Specifically, the membrane assembly 2 includes an upper box 23, a lower box 24, and a membrane body 22. The upper box 23 and the lower box 24 are both longitudinally arranged elongated shells, and are arranged in parallel on the vibrating membrane frame 3 with one higher and one lower. The upper box 23 and the lower box 24 are detachably and fixedly connected to the vibrating membrane frame 3.

[0078] The membrane body 22 consists of several regularly distributed hollow fiber membranes. The type of hollow fiber membrane can be a hydrophobic microfiltration membrane, nanofiltration membrane, dense membrane, or Janus structure membrane, determined based on the feed liquid being processed and the process requirements. Each hollow fiber membrane is arranged vertically, with its upper end fixedly and sealed to the upper housing 23 via an upper mounting base, and its lower end fixedly and sealed to the lower housing 24 via a lower mounting base. The interior of the upper housing 23 communicates with the interior of the lower housing 24 through the inner cavity of the hollow fiber membranes. Specifically, the upper mounting base is fixedly embedded in the bottom plate of the upper housing 23, with its outer wall fixedly and sealed to the bottom plate of the upper housing 23. The lower mounting base is fixedly embedded in the top plate of the lower housing 24, with its outer wall fixedly and sealed to the top plate of the lower housing 24.

[0079] The inlet end of each membrane module 2 is located at the bottom of its lower housing 24, and its outlet end is located at the top of the upper housing 23. The upper housing 23 and lower housing 24 of two vertically adjacent membrane modules 2 are connected and communicate with each other through pipes. That is, the bottom of the lower housing 24 of the upper membrane module is connected to the top of the upper housing 23 of the other membrane module 2 on the lower side through a connecting pipe 25, forming a structure in which membrane modules of the same position are vertically connected in series.

[0080] The diversion module 61 and the junction module 62 are fixedly installed at the bottom and top of the vibrating membrane frame 3, respectively. The top of the diversion module 61 has an outlet end that corresponds to the number and position of each membrane assembly 2. Each outlet end of the diversion module 61 is connected to the inlet end of the corresponding membrane assembly 2 in the bottom layer through a fifth tube 65. The bottom of the junction module 62 has an inlet end that corresponds to the number and position of each membrane assembly 2 in the bottom layer. Each inlet end of the junction module 62 is connected to the outlet end of the corresponding membrane assembly 2 in the top layer through a sixth tube 66. The third tube 63 and the fourth tube 64 both have flexible sections.

[0081] The manifold module 62 is located above the cover. The sixth tube 66 is a two-section flexible tube, with the two parts connected by a rigid joint. The rigid joint is embedded in the cover and seals against it. One part of the sixth tube 66 is located below the cover, and the other part is located above the cover. The cover seals the interior of the membrane tank 1. In operation, the feed liquid inside the membrane tank 1 is under a set pressure. Under a certain pressure, the feed liquid can improve the membrane flux and separation efficiency.

[0082] The manifold module 62 is equipped with an online liquid concentration monitor 2. The signal terminal of the online liquid concentration monitor 2 is connected to the industrial control computer. The online liquid concentration monitor 2 monitors the concentration value of the liquid inside the manifold module 62 in real time and sends the concentration value to the industrial control computer as one of the important indicators for analyzing the operating status of the entire separation device.

[0083] In operation, a cryogenic fluid medium is supplied to the inside of the diversion module 61 through the third pipe 63. The cryogenic fluid medium enters the cavity of the lowest membrane module 2 through the diversion module 61, passes through the cavities of the membrane modules 2 connected in series with it, and collects into the inside of the manifold module 62. It then passes through the fourth pipe 64 and reaches the inside of the liquid collection tank 7 for collection. When the cryogenic fluid medium passes through the cavity of the membrane module 2, the internal cavity pressure of the membrane module 2 is lower than its external pressure. Under the action of the pressure difference, the water vapor in the high-salt wastewater can quickly pass through the membrane body 22 and enter the internal cavity of the membrane module 2. The water vapor entering the membrane module 2 undergoes heat exchange with the cryogenic fluid medium flowing through the membrane module 2 and becomes condensate. It mixes with the cryogenic fluid medium and enters the liquid collection tank 7. It should be emphasized that when separating the high-salt wastewater in the membrane tank 1 and dehydrating the organic solvent, the cryogenic fluid medium used is cryogenic pure water; when separating organic solvents in the membrane tank 1, the cryogenic fluid medium used is the same cryogenic organic solvent as the organic solvent to be separated, that is, the cryogenic fluid medium and the organic solvent to be separated are the same substance.

[0084] The inner side of the vibrating membrane frame 3 has a positioning mechanism that is equal in number and corresponds one-to-one with the membrane assembly 2. All positioning mechanisms are arranged in sequence from left to right. Specifically, the positioning mechanism includes two pairs of mounting plates 31 arranged vertically and vertically. Both pairs of mounting plates 31 are fixedly mounted on the vibrating membrane frame 3. A U-shaped groove for placing the membrane assembly 2 is formed between each pair of mounting plates 31.

[0085] Each U-shaped groove has a long, narrow positioning plate 32 on its inner side. The positioning plate 32 is connected to the mounting plate 31 on its adjacent side by a set of locking bolts 321 arranged longitudinally at intervals. Each set of locking bolts 321 includes multiple locking bolts 321 arranged longitudinally at intervals and screwed onto the mounting plate 31. The positioning plate 32 fixes the upper and lower ends of the membrane assembly 2 between the two pairs of mounting plates 31. The upper box 23 and lower box 24 of the membrane assembly 2 are respectively placed between the two pairs of mounting plates 31. By tightening the locking bolts 321, the positioning plate 32 fixes the upper box 23 and lower box 24 into the vibrating membrane frame 3.

[0086] The vibrating membrane frame 3 drives all membrane modules 2 to vibrate longitudinally and horizontally. The surfaces of all hollow fiber membranes reciprocate relative to the feed liquid. Firstly, this increases the flow velocity on the surface of the hollow fiber membrane, resulting in a larger water vapor pressure on the surface of the hollow fiber membrane. This leads to a larger water vapor pressure difference between the inside and outside of the hollow fiber membrane, thereby increasing the water vapor flux of the hollow fiber membrane and improving its separation performance. Secondly, the reciprocating vibration of the hollow fiber membrane and the rising of bubbles interact to easily form turbulence on the surface of the hollow fiber membrane. This turbulence can greatly reduce the accumulation of large particulate pollutants on the membrane surface, thereby reducing membrane fouling.

[0087] The bubbling unit includes a bubbler 51 and two high-pressure air pipes 58 and 52 located below the membrane module 2. The bubbler 51 is equipped with a first servo motor connected to the industrial control computer. The function of the bubbler 51 is to generate high-pressure air. Two high-pressure air pipes 58 and 52 are provided, and the two high-pressure air pipes 52 are fixedly installed parallel to each other at the bottom of the membrane tank 1. Two high-pressure air pipes 58 are fixedly installed parallel to each other at the bottom of the membrane tank 1, located between the two high-pressure air pipes 52. Aeration discs 581 located on the same high-pressure air pipe 58 are arranged at equal intervals along its length. The aeration discs 581 are located at the top of the high-pressure air pipe 58, and their bottom air inlet ends are connected to the high-pressure air pipe 58. A one-way valve is provided at the connection between the aeration disc 581 and the high-pressure air pipe 58.

[0088] Specifically, the second high-pressure air pipe 52 has micro-nano aeration heads 57 evenly spaced along its length. Each micro-nano aeration head 57 is equipped with a water pump. The second high-pressure air pipe 52 is connected to the air inlet of the micro-nano aeration head 57, and the water outlets of the micro-nano aeration heads 57 on the two second high-pressure air pipes 52 are arranged opposite to each other. The exhaust end of the bubbler is controlled by a three-way valve 54 to independently control the air supply to the first high-pressure air pipe 58 and the second high-pressure air pipe 52. The first high-pressure air pipe 58 and the second high-pressure air pipe 52 operate independently. Specifically, the exhaust end of the bubbler 51 is connected to the air inlet of the three-way valve 54 through the first pipe body 53. The three-way valve 54 has two air outlets. Each first high-pressure air pipe 58 is connected to one air outlet of the three-way valve 54 through the second pipe body 55, and each second high-pressure air pipe 52 is connected to the other air outlet of the three-way valve 54 through the same second pipe body 55. The second pipe body 55 is equipped with a first shut-off valve 59.

[0089] When the aeration disc 581 provides aeration to the membrane tank 1, the compressed air generated by the bubbler 51 enters the high-pressure air pipe 58 through the three-way valve 54 and is discharged through the upper surface of the aeration disc 581, continuously forming uniform large bubbles in the membrane tank 1, and moving rapidly from bottom to top to the surface of the raw material liquid, forming a shear flow in an inclined direction with the back and forth movement of the flat membrane. It should be noted that the large bubbles referred to here are relative to nanobubbles.

[0090] Furthermore, when the micro-nano aerator head 57 provides aeration to the membrane tank 1, the high-pressure air entering the high-pressure air pipe 52 is discharged through the micro-nano aerator head 57, continuously forming uniform nanobubbles in the membrane tank 1. These bubbles move rapidly from bottom to top to the surface of the feed liquid, forming a shear flow in an inclined direction with the back-and-forth movement of the fiber membrane. Specifically, the agitation of the bubbles forms crisscrossing water flows on the membrane surface, thereby generating disturbance and shear forces. Under the action of these forces, pollutants on the membrane surface are detached and reach the surface of the feed liquid with the air drum, reducing the contact between the membrane surface and pollutants. This can greatly reduce organic fouling, inorganic scaling, and microbial adhesion on the membrane, increasing membrane lifespan.

[0091] An electromagnetic flowmeter 56 is installed on the first pipe body 53. The signal terminal of the electromagnetic flowmeter 56 is connected to the industrial control computer for communication. The electromagnetic flowmeter 56 monitors the flow rate of high-pressure air entering the second high-pressure air pipe 52 and adjusts the aeration rate. The bubbling volume per unit time and area can be quantified as the ratio of aeration volume to effluent water of 4 to 50:1. This device provides the membrane tank 1 with the above two aeration modes. The appropriate aeration method can be selected according to the raw material liquid being treated and the process requirements.

[0092] This embodiment improves the membrane's resistance to inorganic salts and organic fouling by controlling the size and quantity of bubbles and coordinating with the vibration system. Vibration and bubbling increase the flow velocity on the membrane surface, thereby increasing water vapor flux. Furthermore, intelligent control of vacuum level and coordinated control of bubbling and vibration to regulate concentration polarization on the membrane surface further enhances the membrane's resistance to organic fouling and inorganic salt scaling. Finally, through the coordinated control of these three aspects, the membrane lifespan can be greatly extended and operating energy consumption reduced, thereby ensuring a highly efficient pervaporation process and improving the quality and efficiency of membrane pervaporation.

[0093] The direct contact pervaporation membrane distillation separation device also includes a heat exchanger 67 and a low-temperature cold source. The low-temperature cold source is connected to the shell-side inlet and outlet pipes of the heat exchanger 67 to form a cold water circulation loop. The liquid collection tank 7 is equipped with an electronic level gauge inside, and a drain pipe 71 is connected to its bottom. A first shut-off valve 72 is installed on the drain pipe. The signal terminals of the electronic level gauge and the first shut-off valve 72 are connected to the industrial control computer. The lower side of the liquid collection tank 7 is connected to the tube-side inlet of the heat exchanger 67 through a seventh tube 73. The tube-side inlet of the heat exchanger 67 is connected to the end of the third tube 63 away from the diversion module 61.

[0094] When dehydrating high-salt wastewater or organic solvents, the low-temperature fluid medium is low-temperature pure water, and the liquid collection tank 7 also collects pure water, which has a higher temperature than the pure water in the diversion module 61. Similarly, when separating organic solvents, the low-temperature fluid medium is the same low-temperature organic solvent as the organic solvent to be separated. The organic solvent separated from the membrane tank 1 is called the target organic solvent, and the organic solvent collected in the liquid collection tank 7 has a higher temperature.

[0095] When the liquid (distilled water or target organic solvent) in the liquid collection tank 7 is required as the fluid medium, a portion of the organic solvent in the liquid collection tank 7 needs to be cooled. Specifically, a portion of the liquid in the liquid collection tank 7 enters the heat exchanger 67 through the seventh tube 73 for cooling, resulting in a low-temperature fluid medium. Then, it is pumped to the diversion module 61 through the third tube 63 and returns to the liquid collection tank 7 in the same manner, ensuring a continuous supply of low-temperature fluid medium to the interior of all membrane modules 2. The low-temperature fluid medium enters the lower shell 24 of the membrane module 2 and flows upward through the inner cavity of the hollow fiber membrane into the upper shell 23 of the membrane module 2. It then enters the upper membrane module 2 through the connecting pipe 25, flowing upward sequentially into the manifold module 62 and finally into the liquid collection tank 7. As the low-temperature fluid medium passes through the interior of the hollow fiber membrane, high-temperature water vapor or the target organic solvent enters through the micropores on the sidewall of the hollow fiber membrane, cooling to form a liquid state, mixing with the low-temperature fluid medium inside the hollow fiber membrane, and being transported upward together. The electronic level gauge monitors the liquid level in the liquid collection tank 7 in real time and periodically drains excess liquid from inside the liquid collection tank 7.

[0096] An online liquid concentration monitor 11 is installed at the lower part of the membrane tank 1. The signal terminal of the online liquid concentration monitor 11 is connected to the industrial control computer. The online liquid concentration monitor 11 monitors the concentration of the feed liquid in the membrane tank 1 in real time. In operation, the concentration of the feed liquid in the membrane tank 1 increases as evaporation proceeds. When the concentration of the feed liquid reaches a set threshold, new feed liquid is added to the membrane tank 1. After the feed liquid in the membrane tank 1 mixes with the newly added feed liquid, the concentration decreases, and separation continues through the membrane module 2.

[0097] When this invention is used for the separation of high-salt wastewater, the water vapor filtered through the membrane module enters the membrane module in the form of steam and undergoes heat exchange. The steam is cooled inside the cooling chamber 201 of the membrane module to form condensate, which flows through the drain pipe 73 into the collection tank 7, and is finally produced as pure liquid water. Taking the application of a nanofiltration membrane (22) in the distillation separation of magnesium-lithium salt solutions as an example, the molecular weight cutoff is between that of reverse osmosis and ultrafiltration membranes, approximately 100–2000 Da. Therefore, it is inferred that the nanofiltration membrane may have a microporous structure with a pore size of approximately 1–5 nm. Applications include the separation of magnesium-lithium salt solutions, removal of organic matter and color from surface water, removal of hardness from groundwater, partial removal of dissolved salts, concentration of fruit juice, and separation of useful substances from pharmaceuticals. The main separation mechanisms include pore size sieving and the synergistic effect of Dornan repulsion, with Dornan repulsion's intramembrane charge repulsion being the dominant mechanism.

[0098] The cleaning system includes a water pump 81 and a main cleaning pipe 82. The water pump 81 is located at one end of the main cleaning pipe 82. The main cleaning pipe 82 has cleaning branch pipes 83, which are equal in number and corresponding in position to the membrane modules 2. The lower end of each cleaning branch pipe 83 can be connected to the upper end of the corresponding air guide pipe 72, and its upper end is connected to the main cleaning pipe 82. The main cleaning pipe 82 is equipped with an electromagnetic gate valve 84, and the signal terminal of the electromagnetic gate valve 84 is connected to the industrial control computer. In the working state, the electromagnetic gate valve 84 is in the closed state. After running for a certain period of time, it is necessary to clean the dirt on the membrane surface. The cleaning system uses a special cleaning agent to backwash the flat membranes on both sides of each membrane module 2 through the cleaning branch pipes 83 into the cooling chamber 202 of each membrane module 2, removing dirt and impurities from the membrane surface.

[0099] Example 3, combined with Figure 2 , Figure 3 , Figure 4 and Figure 6 A direct contact pervaporation membrane distillation separation device is provided. Its main body is the same as that of Embodiment 1. The difference is that it also includes an evaporator crystallizer 9 equipped with a stirring mechanism. The evaporator crystallizer is arranged outside the membrane tank 1. It adopts a sealed shell with a bottom heating function. The inlet of the evaporator crystallizer 9 is connected to the outlet at the bottom of the membrane tank 1 through an eighth tube 91. The eighth tube 91 is equipped with a second shut-off valve 92 and the same delivery pump. A pressure relief valve is provided on the top of the evaporator crystallizer 9.

[0100] The stirring mechanism includes stirring blades 94, a drive shaft, and a third servo motor 95. The third servo motor 95 is installed above the evaporator crystallizer 9, and the stirring blades 94 are located on the lower inner side of the evaporator crystallizer 9. The stirring blades are fixedly connected to the output shaft of the third servo motor 95 through the drive shaft.

[0101] A linear liquid concentration monitor 11 monitors the concentration of the feed liquid in membrane tank 1 in real time. During operation, the concentration of the feed liquid in membrane tank 1 increases as evaporation proceeds. When the concentration reaches a set threshold, the industrial control computer controls the second shut-off valve 92 to open via a signal command. The feed liquid in membrane tank 1 then enters the evaporator crystallizer 9 through the eighth tube 91. Afterward, the second shut-off valve 92 is closed, and new feed liquid is added to membrane tank 1. The concentration decreases after mixing with the newly added feed liquid, and separation continues through membrane module 2. The evaporator crystallizer 9 heats and continuously stirs the high-concentration feed liquid entering it. Once the high-concentration feed liquid in the evaporator crystallizer 9 reaches saturation, crystals continuously precipitate, resulting in crystals within the evaporator crystallizer 9. During the heating and crystallization process, the eighth tube 91 is not conductive.

[0102] Example 4, combined with Figures 2 to 5A direct contact pervaporation membrane distillation separation device is provided. Its main body is the same as that of Embodiment 2. The difference is that it also includes an evaporator crystallizer 9 equipped with a stirring mechanism. The evaporator crystallizer is arranged outside the membrane tank 1. It adopts a sealed shell with a bottom heating function. The inlet of the evaporator crystallizer 9 is connected to the outlet at the bottom of the membrane tank 1 through an eighth tube 91. The eighth tube 91 is equipped with a second shut-off valve 92 and the same delivery pump. A pressure relief valve is provided on the top of the evaporator crystallizer 9.

[0103] The stirring mechanism includes stirring blades 94, a drive shaft, and a third servo motor 95. The third servo motor 95 is installed above the evaporator crystallizer 9, and the stirring blades 94 are located on the lower inner side of the evaporator crystallizer 9. The stirring blades are fixedly connected to the output shaft of the third servo motor 95 through the drive shaft.

[0104] A linear liquid concentration monitor 11 monitors the concentration of the feed liquid in membrane tank 1 in real time. During operation, the concentration of the feed liquid in membrane tank 1 increases as evaporation proceeds. When the concentration reaches a set threshold, the industrial control computer controls the second shut-off valve 92 to open via a signal command. The feed liquid in membrane tank 1 then enters the evaporator crystallizer 9 through the eighth tube 91. Afterward, the second shut-off valve 92 is closed, and new feed liquid is added to membrane tank 1. The concentration decreases after mixing with the newly added feed liquid, and separation continues through membrane module 2. The evaporator crystallizer 9 heats and continuously stirs the high-concentration feed liquid entering it. Once the high-concentration feed liquid in the evaporator crystallizer 9 reaches saturation, crystals continuously precipitate, resulting in crystals within the evaporator crystallizer 9. During the heating and crystallization process, the eighth tube 91 is not conductive.

[0105] For any parts not mentioned in this invention, existing technologies can be used or referenced.

[0106] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0107] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0108] Of course, the above description is not intended to limit the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A direct contact pervaporation membrane distillation separation device, characterized in that, It includes a membrane tank, membrane modules, vibrating membrane frame, reciprocating drive mechanism, bubbling unit, diversion module, manifold module, liquid collection tank, cleaning system and industrial control computer. The vibrating membrane frame is set in the membrane tank, and the reciprocating drive mechanism drives the vibrating membrane frame to move back and forth. The vibrating membrane frame is provided with at least one layer of membrane components. When the number of membrane components is greater than 1, the membrane components are stacked sequentially from bottom to top. Each layer of membrane components includes multiple membrane components arranged horizontally at intervals. All membrane components are vertically fixed on the vibrating membrane frame. Each membrane component in the upper layer is vertically aligned with each membrane component in the adjacent lower layer. The membrane module has an internal cavity, an inlet end and an outlet end, and membrane modules at the same position are connected in series vertically. The diversion module is located at the bottom of the membrane tank, and its inlet is connected to the liquid collection tank pipeline. The manifold module is located above the membrane tank and is connected to the splitting module through the cavities of all membrane components. The outlet of the manifold module is connected to the top pipeline of the liquid collection tank. In operation, the liquid collection tank can continuously pump cryogenic fluid medium into the splitting module. The bubbling unit includes a bubbler, multiple aeration discs, and multiple micro-nano aeration heads. The aeration discs and micro-nano aeration heads are regularly arranged at the bottom of the membrane tank. The bubbler is connected to all aeration discs and all aeration disc pipelines respectively. An online liquid concentration monitor is installed at the bottom of the membrane tank.

2. The pervaporation membrane distillation separation device according to claim 1, characterized in that, The membrane module includes a membrane body and a square rigid frame. The rigid frame is arranged vertically. There are two membrane bodies, both of which are flat sheet membranes. The two membrane bodies are symmetrically arranged on the left and right sides of the rigid frame and are fixedly and sealed to the rigid frame to form the cavity of the membrane module. The inlet and outlet ends of the membrane module are located at the bottom and top of the rigid frame, respectively, and the inlet and outlet ends of two vertically adjacent rigid frames are connected by pipelines.

3. The pervaporation membrane distillation separation device according to claim 1, characterized in that, The membrane assembly includes an upper box, a lower box, and a membrane body. The upper and lower boxes are arranged in parallel relative to each other at different heights and are fixed on the vibrating membrane frame. The membrane body consists of several hollow fiber membranes arranged vertically. The upper end of the hollow fiber membrane is connected to the interior of the upper box, and the lower end is connected to the interior of the lower box. The inlet end of the membrane module is located at the bottom of the lower housing, and its outlet end is located at the top of the upper housing. The upper and lower housings are connected by pipelines.

4. The direct contact pervaporation membrane distillation separation device according to claim 1, characterized in that, The vibrating membrane frame has an open structure, and the inner side of the vibrating membrane frame is provided with a positioning mechanism that is equal in number to the number of membrane components and corresponds to their positions one by one. The positioning mechanism includes two pairs of mounting plates arranged vertically and vertically, with a U-shaped groove formed between each pair of mounting plates. The upper and lower ends of the membrane module are fixed between the two pairs of mounting plates.

5. The direct contact pervaporation membrane distillation separation device according to claim 1, characterized in that, A cover is provided above the membrane tank, and the edge of the cover is fixedly connected to the top of the membrane tank. The vibrating membrane frame is located below the cover. Two connecting frames are symmetrically arranged on the vibrating membrane frame, and two guide rails are provided above the membrane tank. The upper ends of the two connecting frames are respectively longitudinally slidingly engaged with the two guide rails, and the lower ends are fixedly connected to the vibrating membrane frame. The connecting frames are in a movable sealing fit with the cover. The reciprocating drive mechanism includes a second servo motor, a crank, a connecting rod, and a slider bearing housing. One end of the crank is fixedly connected to the output shaft of the second servo motor, and a slider bearing housing sleeve is provided on the crank. One end of the connecting rod is hinged to the slider bearing housing, and the other end is hinged to one of the connecting frames.

6. The direct contact pervaporation membrane distillation separation device according to claim 1, characterized in that, All aeration discs are connected to the bubbler via high-pressure air pipe 1. High-pressure air pipe 1 is arranged horizontally, and the aeration discs are arranged at intervals along the length of high-pressure air pipe 1. All micro-nano aeration heads are connected to the bubbler via high-pressure air pipe 2. High-pressure air pipe 2 is arranged parallel to high-pressure air pipe 1, and the micro-nano aeration heads are arranged at intervals along the length of high-pressure air pipe 2. The bubble machine is connected to the air inlet pipe of the three-way valve, and the two outlet pipes of the three-way valve are respectively connected to the high-pressure air pipe one and the high-pressure air pipe two.

7. The direct contact pervaporation membrane distillation separation device according to claim 1, characterized in that, The diversion module and the junction module are installed at the bottom and top of the vibrating membrane frame, respectively. The top of the diversion module has an outlet end that is equal in number and position to each membrane module. Each outlet end of the diversion module is connected to the inlet end of the corresponding membrane module at the bottom layer through a fifth tube. The bottom of the manifold module has an inlet end that is equal in number and corresponding to the position of each membrane module. Each inlet end of the manifold module is connected to the outlet end of the corresponding membrane module in the uppermost layer through a sixth tube. The manifold module is equipped with an online liquid concentration monitor.

8. The direct contact pervaporation membrane distillation separation device according to claim 1, characterized in that, It also includes a heat exchanger and a low-temperature cold source, with the low-temperature cold source and the shell side of the heat exchanger forming a cold water circulation loop; The liquid collection tank is equipped with a drain pipe at the bottom, and a first shut-off valve is installed on the drain pipe. The lower part of the liquid collection tank is connected to the inlet pipe of the heat exchanger diversion module.

9. The direct contact pervaporation membrane distillation separation device according to claim 1, characterized in that, It also includes an evaporator crystallizer with a bottom heating function, an internal stirring mechanism, an inlet connected to the lower pipeline of the membrane tank, and a pressure relief valve at the top of the evaporator crystallizer.

10. The direct contact pervaporation membrane distillation separation device according to claim 1, characterized in that, The cleaning system includes a water pump and a main cleaning pipe. The water pump is connected to one end of the main cleaning pipe. The main cleaning pipe is equipped with cleaning branch pipes that are equal in number and corresponding in position to the membrane modules. The lower end of each cleaning branch pipe is located on the adjacent side of the corresponding membrane module.

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