A membrane stack design with magnetic force stirring baffle

Abstract

The application is an electrodialysis membrane stack with magnetic stirring partition, which can be applied to common electrodialysis, can realize separation of easy-settling colloidal solution, and mainly comprises the following: polar plate, polar chamber partition, common partition, magnetic stirring partition, diaphragm, magnetic stirring device, end plate and flow channel joint. The magnetic stirring partition of the electrodialysis device is attached with smooth magnetic needle, and can realize uniform rotation in limited space. The application can realize effective enrichment of existing low solubility materials in the electrodialysis device (because the materials will block the flow channel and chamber after crystallization), can solve the problem that the existing common electrodialysis is difficult to process the material liquid containing solid particles, can prevent the precipitation, can configure magnetic stirring to realize uniform and stable outflow of the materials, and can improve the material collection effect of the system.

Description

Technical Field

[0001] This invention relates to membrane separation systems, and in particular to a membrane stack design with a magnetic stirring baffle. Background Technology

[0002] Electrodialysis is a device that uses ion exchange membranes and a direct current electric field to selectively migrate electrolyte ions in water, thereby achieving water desalination.

[0003] Currently, the main material used in electrodialysis is polyethylene. Polyethylene heterogeneous ion exchange membranes contain sufficient fixed groups and dissociable ions, and have a certain degree of selective permeability and conductivity to ions in solution. They are widely used in electrochemical departments to separate different types of ions.

[0004] The use of electrodialysis in industry requires high standards for the influent, particularly the removal of divalent and higher-valent cations to prevent the formation of hydroxide precipitates from metal ions. This places extremely high demands on the application scope of industrial electrodialysis.

[0005] Therefore, existing technologies and equipment need to be improved to adapt to more liquid systems. Summary of the Invention

[0006] This invention provides a membrane stack design with a magnetic stirring baffle to solve the above-mentioned problems.

[0007] One technical solution adopted by the present invention is to provide a membrane stack design with a magnetic stirring baffle, including: an electrode chamber baffle, a common baffle, a magnetic stirring baffle, a membrane, a magnetic stirring device, an end plate, and a flow channel connector.

[0008] Furthermore, the membrane includes anion exchange membranes and cation exchange membranes, through which directional separation of ions is achieved.

[0009] Furthermore, the magnetic stirring baffle is embedded with a magnetic needle, which can achieve stirring at a certain speed under the action of an external magnetic field; the external magnetic stirring device utilizes the principle of like poles repelling and unlike poles attracting to use the magnetic field to drive the magnetic needle to rotate in a circle, thereby achieving the purpose of stirring the liquid.

[0010] Furthermore, the electrode plate is made of titanium-coated tantalum-niobium, the end plate is made of plexiglass, and it connects the inlet and outlet water flows of each liquid chamber; the flow channel connector is made of polyoxymethylene (POM) to enable liquid flow.

[0011] Furthermore, the polar chamber partition has no flow channels; the ordinary partition has centrally symmetrical flow channels.

[0012] Furthermore, the length of the magnetic needle matches the space left inside the magnetic stirring baffle, and its thickness is uniform and less than the thickness of the baffle.

[0013] Furthermore, the magnetic stirring device is connected to a corresponding control valve, which can adjust the magnetic stirring speed.

[0014] This invention relates to a membrane stack design with a magnetic stirring baffle, applicable to conventional electrodialysis. It enables the separation of easily settling colloidal solutions. The membrane stack includes electrode plates, electrode chamber baffles, ordinary baffles, a magnetic stirring baffle, a diaphragm, a magnetic stirring device, end plates, and flow channel connectors. The membrane stack with the baffle mainly comprises: electrode plates, electrode chamber baffles, ordinary baffles, a magnetic stirring baffle, a diaphragm, a magnetic stirring device, end plates, and flow channel connectors. The magnetic stirring baffle of the electrodialysis unit is equipped with smooth magnetic needles, enabling uniform rotation within a confined space. This invention addresses the issue of crystal precipitation in conventional electrodialysis when the concentration in the concentrate chamber is too high. It also addresses the need for uniform flow of solutions containing solid particles in existing electrodialysis to prevent sedimentation by incorporating magnetic stirring to achieve uniform and stable material outflow, thereby improving the system's product collection efficiency. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of a partition design with magnetic stirring as described in this invention.

[0016] Figure 2 This is a schematic diagram of a membrane stack design with a magnetic stirring baffle as described in this invention, which is a common electrodialysis device with a magnetic stirring baffle.

[0017] Figure 3 This is a schematic diagram of the magnetic stirring device and electrodialysis membrane stack described in this invention.

[0018] The components in the attached diagram are labeled as follows: 1. Electrode plate, 2. End plate, 3. Electrode chamber partition, 4. Ordinary partition, 5. Magnetic stirring partition, 6. Diaphragm (yellow for anion exchange membrane, green for cation exchange membrane), 7. Magnetic stirring device, 8. Flow channel connector. Detailed Implementation

[0019] The present invention will be further described below through specific embodiments. However, the scope of the present invention is not limited thereto.

[0020] Example 1

[0021] Attachment Figure 2 The components are stacked in sequence and reinforced with plexiglass. Bolts are used to tighten the electrodialysis membrane stack, ensuring that each bolt is positioned uniformly. Five sets of effective repeating units are placed in the center of the electrodialysis membrane stack.

[0022] This case study employs a six-channel organization method. These channels respectively guide the flow from the concentrate chamber inlet to the concentrate chamber outlet, from the dilute chamber inlet to the dilute chamber outlet, and from the electrode chamber inlet to the electrode chamber outlet.

[0023] The flow rate in each compartment is controlled at 30L / h by the water pump regulating valve. It operates for 1 hour using a 3A constant current DC power supply. Electrodialysis is performed using a 10% lithium hydroxide solution as the alkali source. Using the membrane stack partition design with magnetic stirring of the present invention, the alkali concentration in the alkali endpoint concentration chamber of the original non-magnetically stirred membrane stack electrodialysis is increased from 12% to 17%, and the current efficiency is improved while the energy consumption is reduced.

[0024] Example 2

[0025] The difference between this embodiment and Embodiment 1 is that:

[0026] Conventional electrodialysis is used, with a six-channel system. These channels guide the flow from the concentrate chamber inlet to the concentrate chamber outlet, from the dilute chamber inlet to the dilute chamber outlet, and from the electrode chamber inlet to the electrode chamber outlet.

[0027] The flow rate in each compartment was controlled at 30 L / h via a water pump regulating valve. The solution was electrodialyzed for 2 hours using a 2A constant current DC power supply to treat viscose fiber pressing alkali liquor produced by a factory. The control group with ordinary separators achieved an 82% NaOH removal rate, while the NaOH removal rate using magnetically stirred separators reached over 98% with similar energy consumption. Compared to membrane stacks without magnetic needles, the final alkali concentration was also improved.

[0028] Table 1 is a comparison table of test results for Embodiment 1 and Embodiment 2 of the present invention.

[0029] Table 1. Comparison of test results for Example 1 of the present invention

[0030] project Electrodialysis alkaline endpoint concentration (%) Current efficiency (%) Energy consumption per ton of alkali (kWh / ton of LiOH) Example 1 17 68 2752 Comparative Example 1 (without magnetic stirring) 12 42 4103

[0031] Table 2 Comparison of test results for Example 2 of the present invention

[0032] project Electrodialysis alkaline concentration at the final concentration chamber (mol / L) Current efficiency (%) Energy consumption per ton of alkali (kWh / ton of NaOH) NaOH removal rate Example 2 0.98 91 862 98% Comparative Example 2 (without magnetic stirring) 0.82 76 1608 82%

Claims

1. A membrane stack with a magnetic stirring baffle, characterized in that, include: The system comprises a diaphragm, end plate, electrode chamber diaphragm, ordinary diaphragm, electrode plate, flow channel connector, magnetic stirring diaphragm, and magnetic stirring device. The magnetic stirring diaphragm is embedded with a magnetic needle, which stirs at a speed of 0-1000 rpm under the action of an external magnetic field. The length and width of the magnetic stirring diaphragm are both between 10cm and 100cm, matching the diaphragm. The width of the flow channel does not exceed 5% of the diaphragm width. The magnetic needle is externally coated with a PTFE-based film using a hot-melt method to prevent the needle from being worn down and contaminating the liquid phase when handling liquids that react with it. The magnetic needle is one of neodymium iron boron magnets, samarium cobalt magnets, alnico magnets, and ferrite magnets. The length of the magnetic needle matches the space left inside the magnetic stirring diaphragm. The magnetic needles are uniform in thickness; their diameter is smaller than the thickness of the partition; the magnetic needles are one of three types: olive-shaped, cylindrical with a collar, and long cylindrical without a collar, each designed for electrodialysis of different liquid phase systems; the magnetic stirring device utilizes the principle of like poles repelling and unlike poles attracting to drive the magnetic needles in circular motion, thereby stirring the liquid; the magnetic field is based on the principle of electromagnetic induction, introducing an alternating magnetic field into each compartment to cause the magnetic needles to rotate, thus achieving liquid stirring; the magnetic stirring device includes an external control valve to control the switch and the magnitude of the magnetic field, and also includes a speed control module connected to relays with different coil windings to regulate the stirring speed; the partition is composed of anion exchange membranes and cation exchange membranes.

2. The membrane stack with a magnetic stirring baffle according to claim 1, characterized in that, The membrane stack achieves directional ion separation through a diaphragm; the end plate is made of plexiglass and is designed to connect the inlet and outlet water flow of the feed chamber; the electrode chamber partition has no flow channels; the ordinary partition has centrally symmetrical flow channels; the electrode plate is made of titanium coated with tantalum and niobium; the flow channel connector is made of polyoxymethylene to enable liquid flow.

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