Membrane assembly with flexible turbulent flow fins for membrane distillation seawater desalination system

Abstract

The invention discloses a membrane assembly with flexible turbulent flow fins for a membrane distillation seawater desalination system, which is characterized by comprising an upper wall, a lower wall, a distillation membrane and flexible fin plates, a hot material liquid channel is formed in the upper wall; a cold material liquid channel is formed in the lower wall; the distillation film is arranged between the upper wall and the lower wall, and two sides of the distillation film are respectively communicated with the hot feed liquid channel and the cold feed liquid channel; a plurality of flexible fins are arranged on the side, facing the distillation film, of the flexible fin plate, and the flexible fin plate is arranged in the hot material liquid channel. The membrane module can effectively weaken the polarization phenomenon and improve the heat and mass transfer capacity and the anti-pollution capacity.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of membrane distillation, and more particularly to a membrane assembly with flexible turbulence fin for a membrane distillation seawater desalination system. BACKGROUND

[0002] Direct contact membrane distillation (DCMD) is a high-efficiency membrane separation technology based on temperature difference driving. Its principle is to use the selective mass transfer characteristics of hydrophobic microporous membranes: the high-temperature feed liquid (such as salt water) on the membrane surface evaporates to produce steam, the steam molecules diffuse through the membrane pores to the low-temperature permeate liquid (such as pure water) and condense, while the solute (such as salt ions or pollutants) cannot be vaporized and is intercepted, thereby realizing the separation of solute and solvent. The advantages of this technology include low operating temperature (can utilize waste heat or solar energy), high separation efficiency (almost 100% rejection of non-volatile substances), and strong adaptability to high-salinity wastewater.

[0003] However, the existing DCMD technology has the following technical problems:

[0004] Temperature polarization phenomenon: During the membrane distillation process, due to the heat conduction occurring in the membrane and the endothermic evaporation of water on the membrane surface, the temperature at the membrane surface on the feed liquid side is lower than the bulk temperature of the feed liquid, and the temperature at the membrane surface on the condensation side is higher than the bulk temperature of the condensation liquid, thereby generating a temperature boundary layer and causing temperature polarization phenomenon. Temperature polarization phenomenon causes the actual transmembrane temperature difference to be smaller than the bulk temperature difference on both sides of the membrane, reducing the vapor pressure difference on both sides of the membrane (the driving force of the membrane distillation process), thereby hindering the mass transfer of the membrane.

[0005] Concentration polarization phenomenon: During the membrane distillation process, due to the preferential evaporation of water molecules through the membrane, while the solute (such as salt) is intercepted on the feed liquid side as it cannot pass through the membrane, the solute concentration at the membrane surface on the feed liquid side is higher than the bulk concentration of the feed liquid, thereby forming a significant concentration gradient between the membrane surface and the bulk fluid. This phenomenon reduces the actual effective mass transfer driving force of the membrane and affects the separation efficiency.

[0006] Membrane fouling problem: High-concentration solute may crystallize or deposit on the membrane surface, blocking the membrane pores, increasing the mass transfer resistance, and even causing the membrane to fail. These deficiencies limit the large-scale industrial application of DCMD, and further breakthroughs are needed through membrane material modification or process optimization.

[0007] Therefore, it is an urgent problem for those skilled in the art to develop a membrane assembly with flexible turbulence fin for a membrane distillation seawater desalination system that can effectively weaken polarization phenomenon, improve heat and mass transfer capacity, and improve anti-pollution ability. SUMMARY

[0008] Therefore, the application provides a membrane assembly with flexible turbulence fin for a membrane distillation seawater desalination system, which can effectively weaken polarization, improve heat and mass transfer capacity and anti-pollution capacity.

[0009] In order to achieve the above object, the application adopts the following technical scheme:

[0010] The membrane assembly with flexible turbulence fin for a membrane distillation seawater desalination system comprises:

[0011] An upper wall, in which a hot feed liquid channel is formed;

[0012] A lower wall, in which a cold feed liquid channel is formed;

[0013] A distillation membrane, which is arranged between the upper wall and the lower wall, and the two sides of the distillation membrane are connected with the hot feed liquid channel and the cold feed liquid channel respectively;

[0014] A flexible fin plate, which is provided with a plurality of flexible fins on one side facing the distillation membrane, and the flexible fin plate is arranged in the hot feed liquid channel.

[0015] The above technical scheme has the beneficial effects that the flexible fins can enhance turbulence, destroy temperature and concentration boundary layers, and effectively reduce temperature polarization and concentration polarization; by enhancing turbulence, the contact efficiency of the hot feed liquid and the distillation membrane is improved, and the heat and mass transfer rate is accelerated; the reciprocating motion of the flexible fins can change the fluid flow direction, form complex vortex flow, and prevent pollutants and crystalline substances from accumulating on the membrane surface.

[0016] Preferably, rubber gaskets are arranged between the upper wall and the distillation membrane and between the lower wall and the distillation membrane, and the rubber gaskets are tightly pressed around the distillation membrane. The rubber gaskets can effectively seal and prevent the hot feed liquid and the cold feed liquid from leaking, thereby ensuring stable operation of the system.

[0017] Preferably, a groove is arranged at a position corresponding to the distillation membrane at the bottom of the upper wall, and a shunt groove is formed at both ends of the groove and connected with the hot feed liquid channel; the hot feed liquid in the hot feed liquid channel first passes through the shunt groove and then flows into the groove uniformly. The design of the shunt groove ensures that the hot feed liquid flows into the groove uniformly and fully contacts with the distillation membrane.

[0018] Preferably, turbulence columns are arranged at one end of the groove where the hot feed liquid enters, and a plurality of the turbulence columns are arranged transversely in the groove and connected with the groove wall.

[0019] Preferably, the plurality of flexible fins are uniformly arranged on the flexible fin plate, and the transverse spacing is 4-8 mm and the longitudinal spacing is 4-8 mm.

[0020] It can be seen from the above technical solution that, compared with the prior art, the present invention discloses a membrane module with flexible flow-turbulating fins for a membrane distillation seawater desalination system, which has the following beneficial effects:

[0021] (1) The membrane assembly of the present invention has stronger disturbance than the existing direct contact membrane distillation membrane assembly. Through the flow disturbance column, the hot liquid will generate strong disturbance flow after flowing through, thereby driving the flexible fins to swing back and forth, destroying the temperature boundary layer and concentration boundary layer on the hot liquid side, greatly reducing the enrichment of pollutants on the membrane surface, and thus reducing the risk of membrane fouling;

[0022] (2) The installation of flexible turbulent fins in the hot liquid channel greatly improved the temperature and concentration polarization phenomenon, and improved the flux and thermal efficiency of membrane distillation. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0024] Figure 1 An internal cross-sectional view of the membrane assembly provided by the present invention;

[0025] Figure 2 The present invention provides Figure 1 The main view;

[0026] Figure 3 A schematic diagram of the structure of the flexible fins provided by the present invention distributed on the flexible fin plate;

[0027] Figure 4 A schematic diagram comparing the static and moving states of the flexible fin provided by the present invention.

[0028] Among them, in the figure,

[0029] 1-upper wall;

[0030] 11-hot liquid channel; 12-groove; 13-diverter trough;

[0031] 2-lower wall;

[0032] 21-cold liquid channel;

[0033] 3-distillation membrane; 4-flexible fin plate; 5-flexible fin; 6-rubber gasket; 7-turbine column.

[0034] Need special note: A indicates the flow direction of hot liquid; B indicates the flow direction of cold liquid; C indicates the flexible fin in the static state; D indicates the flexible fin in the reciprocating state. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0036] The embodiments of the present application disclose a membrane assembly with flexible spoiler fins for a membrane distillation seawater desalination system, comprising:

[0037] The upper wall 1 is provided with a hot liquid channel 11.

[0038] The lower wall 2 is provided with a cold liquid channel 21.

[0039] The distillation membrane 3 is arranged between the upper wall 1 and the lower wall 2, and the two sides of the distillation membrane 3 are connected with the hot liquid channel 11 and the cold liquid channel 21 respectively.

[0040] The flexible fin plate 4 is provided with a plurality of flexible fins 5 on the side facing the distillation membrane 3, and the flexible fin plate 4 is arranged in the hot liquid channel 11.

[0041] In order to further optimize the above technical solutions, the rubber gasket 6 is arranged between the upper wall 1 and the distillation membrane 3 and between the lower wall 2 and the distillation membrane 3, and the rubber gasket 6 is tightly pressed around the distillation membrane 3. The rubber gasket 6 is fixed with the upper wall 1 and the lower wall 2 by bolts, which can play a sealing role to prevent liquid leakage.

[0042] In order to further optimize the above technical solutions, the recess 12 is arranged at the corresponding position of the distillation membrane 3 at the bottom of the upper wall 1, and the flow dividing groove 13 is arranged at the connecting part of the two ends of the recess 12 and the hot liquid channel 11; the hot liquid in the hot liquid channel 11 first flows into the flow dividing groove 13 and then uniformly flows into the recess 12. The hot liquid enters the hot liquid channel 11, first flows into the flow dividing groove 13, and then uniformly flows into the recess 12. The uniform flow of the hot liquid in the recess 12 can make the hot liquid uniformly and fully contact the distillation membrane 3.

[0043] In order to further optimize the above technical solutions, the spoiler column 7 is arranged at one end of the recess 12 where the hot liquid enters, and a plurality of spoiler columns 7 are arranged transversely in the recess 12 and connected with the groove wall of the recess 12.

[0044] To further optimize the above technical solutions, after the hot feed passes through the turbulence column 7, due to the viscosity and inertia of the hot feed, opposite rotating vortices are alternately generated behind the object, the frequency of the alternating shedding of the vortices is consistent with the frequency of the change of the lift direction, a periodic alternating force is formed to drive the flexible fin 5 to reciprocate. The flexible fin 5 reciprocates in the process of the hot feed flowing, increases the turbulence intensity of the hot feed, and makes the temperature boundary layer and the concentration boundary layer be continuously destroyed and regenerated. Under the turbulent flow state, the micro-mixing of the hot feed inside is more sufficient, and the heat and mass transfer rates are also accelerated. The reciprocating movement of the flexible fin 5 can change the flow direction of the hot feed in the micro-channel, form a complex vortex flow, and intensify the disturbance on the membrane surface, so that the pollutants and crystalline substances are not easy to accumulate on the membrane surface, thereby reducing the risk of membrane pollution.

[0045] To further optimize the above technical solutions, a plurality of flexible fins 5 are uniformly arranged on the flexible fin plate 4, the horizontal spacing is 4-8mm, and the vertical spacing is 4-8mm. The height of the flexible fin 5 is 3mm, and the width is 5.6mm.

[0046] The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the difference from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0047] The above description of the disclosed embodiments enables a person skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A membrane module with flexible flow-disturbing fins for a membrane distillation seawater desalination system, characterized in that: include: An upper wall, wherein a hot liquid channel is provided in the upper wall; A lower wall, wherein a cold material liquid channel is opened in the lower wall; a distillation membrane, the distillation membrane being placed between the upper wall and the lower wall, and the two sides of the distillation membrane being respectively connected to the hot liquid channel and the cold liquid channel; A flexible fin plate is provided with a plurality of flexible fins on a side of the flexible fin plate facing the distillation membrane, and the flexible fin plate is provided in the hot liquid channel.

2. The membrane assembly with flexible flow-turbulating fins for a membrane distillation seawater desalination system according to claim 1, characterized in that: Rubber gaskets are provided between the upper wall and the distillation membrane, and between the lower wall and the distillation membrane. The rubber gaskets are pressed tightly around the distillation membrane.

3. The membrane assembly with flexible flow-turbulating fins for a membrane distillation seawater desalination system according to claim 1, characterized in that: A groove is provided at the bottom of the upper wall at a position corresponding to the distillation membrane, and diversion grooves are provided at the connection positions between the two ends of the groove and the hot liquid channel; the hot liquid in the hot liquid channel first passes through the diversion groove and then flows evenly into the groove.

4. The membrane assembly with flexible flow-turbulating fins for a membrane distillation seawater desalination system according to claim 3, characterized in that: The groove is provided with a spoiler column at one end thereof where the hot liquid enters, and a plurality of the spoiler columns are arranged transversely in the groove and connected to the groove wall of the groove.

5. The membrane assembly with flexible flow-turbulating fins for a membrane distillation seawater desalination system according to claim 1, characterized in that: The plurality of flexible fins are evenly arranged on the flexible fin plate, with a lateral spacing of 4-8 mm and a longitudinal spacing of 4-8 mm.

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