Magnetic nanoparticle composite membrane assembly for air-swept membrane distillation system

Abstract

The invention discloses a magnetic nanoparticle composite membrane assembly for an air-swept membrane distillation system. The magnetic nanoparticle composite membrane assembly comprises an upper wall, a lower wall, a distillation membrane and an annular circuit, a purging gas channel is formed in the upper wall; a hot material liquid channel is formed in the lower wall; magnetic nanoparticles are added into the distillation membrane, the distillation membrane is arranged between the upper wall and the lower wall, the top of the distillation membrane is communicated with the purging gas channel, and the bottom of the distillation membrane is communicated with the hot feed liquid channel; the loop circuit is disposed below the lower wall. The composite membrane assembly can effectively reduce the temperature polarization of the distillation membrane and improve the mass transfer efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of membrane distillation, and more particularly to a magnetic nanoparticle composite membrane component for a gas-sweeping membrane distillation system. Background Art

[0002] Membrane distillation (MD), as a highly efficient separation technology, has recently demonstrated broad application potential in fields such as seawater desalination, wastewater treatment, and chemical separation. Its basic principle is to utilize the porous structure of the membrane to allow liquid to evaporate on one side, while vapor condenses on the other side through the membrane pores, thereby achieving liquid separation and purification. Currently, traditional distillation membranes are primarily made of polymer materials such as polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVDF). These materials possess excellent chemical and thermal stability, adapting to complex operating environments.

[0003] However, during the operation of membrane distillation, temperature polarization and concentration polarization occur, which significantly affect the efficiency of heat and mass transfer. Temperature polarization is mainly caused by the evaporation and condensation of water on the membrane surface, resulting in the membrane surface temperature being different from the mainstream temperature. Specifically, on the feed liquid side, due to the absorption of heat by evaporation on the membrane surface, the membrane surface temperature decreases and becomes lower than the mainstream temperature; on the condensation side, due to the release of heat by water condensation, the membrane surface temperature is higher than the mainstream temperature. This change in temperature difference reduces the temperature difference between the two sides of the membrane, reduces the driving force for mass transfer, and thus reduces the flux and thermal efficiency of membrane distillation.

[0004] Therefore, it is an urgent problem for those skilled in the art to develop a magnetic nanoparticle composite membrane component for a gas-swept membrane distillation system that can effectively reduce temperature polarization and improve mass transfer efficiency. Summary of the Invention

[0005] In view of this, the present invention provides a magnetic nanoparticle composite membrane component for a swept-air membrane distillation system, which can effectively reduce temperature polarization and improve mass transfer efficiency.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A magnetic nanoparticle composite membrane assembly for a swept air membrane distillation system, comprising:

[0008] an upper wall, wherein a purge gas channel is formed in the upper wall;

[0009] a lower wall, wherein a hot liquid channel is provided in the lower wall;

[0010] a distillation membrane, wherein magnetic nanoparticles are added to the distillation membrane, the distillation membrane is placed between the upper wall and the lower wall, and the top of the distillation membrane is connected to the purge gas channel, and the bottom of the distillation membrane is connected to the hot liquid channel;

[0011] a ring-shaped circuit arranged below the lower wall.

[0012] The beneficial effects of the above technical solution are that by adding magnetic nanoparticles in the distillation membrane and combining with the ring-shaped circuit to generate an alternating magnetic field, the magnetic nanoparticles generate magnetic heat through the magnetic hysteresis loss and relaxation loss mechanism, effectively reducing the temperature polarization on both sides of the membrane, increasing the driving force of the steam transport to the permeation side, and thus improving the mass transfer efficiency.

[0013] 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 arrangement of the rubber gaskets can effectively press the distillation membrane around, so that the sealing effect between the upper wall and the distillation membrane and between the lower wall and the distillation membrane is better, preventing the leakage of hot liquid and purge gas during operation, and ensuring the normal operation of the membrane distillation system.

[0014] Preferably, a groove is arranged at a position corresponding to the distillation membrane at the top of the lower wall, and a shunt groove is arranged at both ends of the groove and connected to the hot liquid channel. The hot liquid in the hot liquid channel first flows into the groove through the shunt groove. The design of the shunt groove allows the hot liquid to flow uniformly into the groove, thereby ensuring that the hot liquid fully contacts the distillation membrane and avoiding the local overheating or overcooling of the hot liquid on the surface of the distillation membrane, improving the uniformity of heat and mass transfer, and further improving the efficiency of membrane distillation.

[0015] Preferably, the pore size of the distillation membrane is 0.2-0.4 μm.

[0016] Preferably, the ring-shaped circuit generates an alternating magnetic field when a high-frequency alternating current is passed through it, and the frequency of the magnetic field is 0.05-10 MHz. Under the action of the alternating magnetic field in this frequency range, the magnetic nanoparticles in the distillation membrane can fully generate a magnetic heat effect, effectively reduce the temperature polarization on both sides of the membrane, and improve the mass transfer efficiency of membrane distillation.

[0017] Through the above technical solution, compared with the prior art, the present disclosure provides a kind of magnetic nano-particle composite membrane assembly for gas scanning type membrane distillation system, and its beneficial effects are:

[0018] (1) The distillation membrane is added with magnetic nanoparticles, which generates magnetic heat under the action of a magnetic field, reduces temperature polarization, and increases the driving force of steam transport to the permeation side;

[0019] (2) The thermal efficiency of the gas scanning type membrane distillation is high, the purge gas can make the membrane distillation assembly have a long service life, and when the membrane is slightly hydrophilic and wet or damaged, the liquid will not contaminate the condensate, and the liquid will not be lost. BRIEF DESCRIPTION OF DRAWINGS

[0020] 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.

[0021] Figure 1 An internal cross-sectional view of the composite membrane assembly provided by the present invention;

[0022] Figure 2 The present invention provides Figure 1 The main view;

[0023] Figure 3 This is a schematic diagram of the working principle of the composite membrane assembly provided by the present invention.

[0024] 1-upper wall;

[0025] 11-purge gas channel;

[0026] 2-lower wall;

[0027] 21-hot liquid channel; 22-groove; 23-diverter slot;

[0028] 3-distillation membrane; 4-ring circuit; 5-rubber gasket.

[0029] It should be noted that: A represents the magnetic nanoparticles on the distillation membrane; B represents the eddy current generated by the magnetic nanoparticles; C represents the hot liquid; D represents water vapor; and E represents the purge gas. DETAILED DESCRIPTION

[0030] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0031] The embodiment of the present invention discloses a magnetic nanoparticle composite membrane assembly for a swept air membrane distillation system, comprising:

[0032] The upper wall 1 has a purge gas passage 11 formed therein;

[0033] The lower wall 2 has a hot liquid channel 21 formed therein;

[0034] A distillation membrane 3, wherein magnetic nanoparticles are added to the distillation membrane 3, and the distillation membrane 3 is placed between the upper wall 1 and the lower wall 2, and the top of the distillation membrane 3 is connected to the purge gas channel 11, and the bottom is connected to the hot liquid channel 21;

[0035] The ring circuit 4 is arranged below the lower wall 2 .

[0036] In order to further optimize the above technical solution, the distillation membrane 3 with magnetic nanoparticles adopts the solution blending method to add magnetic nanoparticles. During preparation, the magnetic nanoparticles are first modified to reduce agglomeration, and then the magnetic nanoparticles are evenly dispersed into the solution of distillation membrane powder such as PVDF or PTFE by ultrasonic stirring, and finally processed into a finished distillation membrane.

[0037] In order to further optimize the above technical solution, the magnetic nanoparticles can be ferrite magnetic particles (CoFe2O4, NiFe2O4), metal oxide magnetic particles (Fe3O4), and metal alloy magnetic particles (FeNi, FeCo).

[0038] In order to further optimize the above technical solution, the purge gas is air or nitrogen. Driven by a fan, the purge gas carries the water vapor that has passed through the membrane to a cooler outside the composite membrane module for cooling. The water vapor therein is condensed into condensate and then discharged.

[0039] To further optimize the above technical solution, rubber gaskets 5 are installed between the upper wall 1 and the distillation membrane 3, and between the lower wall 2 and the distillation membrane 3. The rubber gaskets 5 are tightly pressed against the periphery of the distillation membrane 3. The rubber gaskets 5 are fixed to the upper wall 1 and the lower wall 2 by bolts. This fixing method improves the sealing effect between the upper wall 1, the lower wall 2 and the distillation membrane 3.

[0040] To further optimize the above technical solution, a groove 22 is provided at the top of the lower wall 2, corresponding to the distillation membrane 3. Diverter grooves 23 are provided at both ends of the groove 22 where they connect to the hot liquid channel 21. The hot liquid in the hot liquid channel 21 first flows through the diverter grooves 23 before evenly flowing into the groove 22. The diverter grooves 23 ensure that the hot liquid is evenly distributed within the groove 22 before flowing through the distillation membrane 3, ensuring sufficient contact between the hot liquid and the distillation membrane 3.

[0041] In order to further optimize the above technical solution, the pore size of the distillation membrane 3 is 0.2-0.4 μm.

[0042] In order to further optimize the above technical solutions, the annular circuit 4 is connected with high-frequency alternating current, and an alternating magnetic field is generated, the frequency of the magnetic field is 0.05-10 MHz. The annular circuit 4 is away from the lower wall 2 by a certain distance, under the action of the external alternating magnetic field, the magnetic nanoparticles uniformly distributed in the distillation membrane 3 generate eddy current due to hysteresis loss and relaxation loss, thereby generating magnetic heat, and reducing temperature polarization. When the hot liquid flows through the distillation membrane 3, under the action of the externally applied magnetic field, the magnetic nanoparticles added in the membrane can be heated in situ due to hysteresis loss and relaxation loss, the heat generated is uniform and controllable, which can effectively increase the local temperature of the distillation membrane, reduce the temperature polarization caused by the heat absorption and evaporation of the liquid on the liquid side, increase the component driving force caused by the temperature difference on both sides of the membrane, and increase the membrane flux.

[0043] Working principle:

[0044] The hot liquid enters from the entering end of the hot liquid channel 21, first enters the shunt groove 23, and then uniformly enters the groove 22, and the hot liquid in the groove 22 is in uniform contact with the distillation membrane 3, the hot liquid evaporates on the surface of the distillation membrane 3, and the water vapor formed by evaporation passes through the distillation membrane 3; the sweep gas enters the sweep gas channel 11 under the drive of the fan and carries the water vapor after passing through the distillation membrane 3 to the cooler outside the membrane distillation assembly for cooling, and the water vapor therein is condensed into condensed liquid and discharged; at the same time, the annular circuit 4 is connected with power, an alternating magnetic field is formed, under the action of the alternating magnetic field, the magnetic nanoparticles in the distillation membrane 3 generate eddy current due to hysteresis loss and relaxation loss, thereby generating magnetic heat, and further reducing the temperature difference on both sides of the distillation membrane 3.

[0045] The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the difference from other embodiments, and the same or similar parts between the various embodiments can be referred to each other.

[0046] 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 magnetic nanoparticle composite membrane assembly for a swept air membrane distillation system, characterized in that: include: an upper wall, wherein a purge gas channel is formed in the upper wall; a lower wall, wherein a hot liquid channel is provided in the lower wall; a distillation membrane, wherein magnetic nanoparticles are added to the distillation membrane, the distillation membrane is placed between the upper wall and the lower wall, and the top of the distillation membrane is connected to the purge gas channel, and the bottom of the distillation membrane is connected to the hot liquid channel; A ring circuit is arranged below the lower wall.

2. The magnetic nanoparticle composite membrane assembly for a swept-gas membrane distillation 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 magnetic nanoparticle composite membrane assembly for a swept-gas membrane distillation system according to claim 1, characterized in that: A groove is provided at the top of the lower wall corresponding to the distillation membrane, and diversion grooves are provided at the connection parts of 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 magnetic nanoparticle composite membrane assembly for a swept-gas membrane distillation system according to claim 3, characterized in that: The pore size of the distillation membrane is 0.2-0.4 μm.

5. The magnetic nanoparticle composite membrane assembly for a swept-gas membrane distillation system according to claim 1, characterized in that: When a high-frequency alternating current is passed through the annular circuit, an alternating magnetic field is generated, and the frequency of the magnetic field is 0.05-10 MHz.

Images