Multifunctional bipolar membrane electrodialysis device

Abstract

This invention provides a multifunctional bipolar membrane electrodialysis device, belonging to the technical field of electrodialysis separation equipment. The multifunctional bipolar membrane electrodialysis device includes a working chamber, a stacked membrane assembly, a brine storage tank, an acid storage tank, an alkali storage tank, an electrode liquid storage tank, and four peristaltic pumps. The four peristaltic pumps are fixed inside the working chamber, and the stacked membrane assembly is fixed at the front end of the working chamber. The left electrode chamber frame plate, acid chamber frame plate, brine chamber frame plate, alkali chamber frame plate, and right electrode chamber frame plate are all square flat plates with flow channels formed between the inlet and outlet channels. The flow channels contain horizontally staggered guide plates, each with a row of serrations on its lower surface. The horizontally staggered guide plates combined with the serrated flow disturbance structure in the flow channels force solution agitation and diffusion, prolonging the flow time of the solution within the flow channels, covering the entire membrane surface, eliminating dead zones and short-circuit flow, and significantly improving ion migration efficiency and current efficiency.

Description

Technical Field

[0001] This invention relates to the field of electrodialysis separation equipment technology, specifically to a multifunctional bipolar membrane electrodialysis device. Background Technology

[0002] Bipolar membrane electrodialysis (BMED) is a green separation technology that uses the water dissociation function of a bipolar membrane to convert salt solutions into corresponding acids and bases under the action of a DC electric field. It is widely used in experimental research and pilot-scale process development in fields such as chemical engineering, environmental protection, and food.

[0003] For example, the invention patent published in China entitled "A Bipolar Membrane Electrodialysis Device" [Application No.: CN202310824869.7] includes an outer casing. The bipolar membrane electrodialysis device also includes: a liquid inlet mechanism; multiple electrodialysis mechanisms; and multiple filtration mechanisms. The filtration mechanism includes a filter box, an active filtration component, and a liquid delivery component. The active filtration component includes a motor installed on the top of the filter box. The output shaft of the motor is fixedly connected to a threaded rod. The outer periphery of the threaded rod is threadedly connected to a filter plate that is slidably connected to the inner wall of the filter box. Multiple plug rods matching the filter holes of the filter plate are fixedly connected to the bottom inner wall of the filter box. The raw water is transported into the filter box through the liquid inlet mechanism. After being actively filtered without turbulence by the active filtration component, it is transported to the corresponding electrodialysis mechanism for further electrodialysis treatment through the liquid delivery component.

[0004] The above-mentioned bipolar membrane electrodialysis device has the following technical defects: the flow channel structure of the membrane stack chamber frame plate in the electrodialysis tank is simple, mostly straight or simple grid, the solution cannot uniformly cover the membrane surface, there are flow dead zones and short-circuit flow, which reduces ion migration efficiency and current efficiency. Summary of the Invention

[0005] The purpose of this invention is to address the aforementioned problems in existing technologies by proposing a multifunctional bipolar membrane electrodialysis device, which is mainly used in small-scale research scenarios such as laboratory bipolar membrane electrodialysis experiments, salt conversion and acid-base preparation, and high-salt wastewater resource utilization.

[0006] The objective of this invention can be achieved through the following technical solution: A multifunctional bipolar membrane electrodialysis device, comprising a working chamber, a stacked membrane assembly, a brine storage tank, an acid storage tank, an alkali storage tank, an electrode liquid storage tank, and four peristaltic pumps. The four peristaltic pumps are fixed inside the working chamber. The working chamber also houses a DC regulated power supply and a PLC module for controlling the start / stop and voltage / current output of the peristaltic pumps. The stacked membrane assembly is fixed at the front end of the working chamber. The stacked membrane assembly includes, from left to right, an anode electrode plate, a left electrode chamber frame plate, a first bipolar membrane, an acid chamber frame plate, an anion exchange membrane, a brine chamber frame plate, a cation exchange membrane, an alkali chamber frame plate, a second bipolar membrane, and a right electrode chamber frame plate. The plate and cathode electrode plate, the left electrode chamber frame plate, acid chamber frame plate, salt chamber frame plate, alkali chamber frame plate and right electrode chamber frame plate are all provided with liquid inlet channel and liquid outlet channel. The inlet of the four peristaltic pumps is connected to the bottom of the corresponding liquid storage tank through the liquid extraction pipe. The outlet of the peristaltic pump is connected to the pipeline buffer. The pipeline buffer is connected to the liquid inlet channel through the intermediate pipe. The liquid outlet channel is connected to the liquid outlet pipe connected to the upper port of the corresponding liquid storage tank. The left electrode chamber frame plate, acid chamber frame plate, salt chamber frame plate, alkali chamber frame plate and right electrode chamber frame plate are all square flat plates and have flow channel grooves opened between the liquid inlet channel and the liquid outlet channel. The flow channel groove is provided with horizontally staggered guide plates. The lower end face of the guide plate has a row of serrations.

[0007] Furthermore, the staggered spacing between adjacent drainage plates is 3mm to 8mm.

[0008] Furthermore, the serrations at the lower end of the drainage plate are isosceles serrations with a serration depth of 0.5mm to 2mm.

[0009] Furthermore, the left and right electrode chamber frame plates share a single inlet and outlet flow channel. This simplifies the electrode liquid circulation pipeline structure and reduces the risk of leakage.

[0010] Furthermore, the outlet channels of the acid chamber frame plate, salt chamber frame plate, and alkali chamber frame plate are located at the same height at the upper end of the stacked membrane stack assembly, while the inlet channels of the acid chamber frame plate, salt chamber frame plate, and alkali chamber frame plate are located at the same height at the lower end of the stacked membrane stack assembly. This forms a bottom-in, top-out full-liquid distribution structure, completely eliminating air bubbles within the membrane stack and ensuring uniform solution filling.

[0011] Furthermore, the pipeline buffer is a cylinder closed at both ends, with the upper and lower ends serving as connection points. The pipeline buffer continuously eliminates peristaltic pump pulsation, ensuring stable flow within the flow channel.

[0012] Furthermore, the anode electrode plate and the cathode electrode plate are clamped and fixed to the front end of the working box by bolts, and the anode electrode plate and the cathode electrode plate are connected to a DC regulated power supply by wires.

[0013] The stacked membrane assembly is bolted together, and the membranes are tightly attached to both sides of the chamber frame mesh plate. The solution flows in the flow channel. The horizontally staggered flow guide plates, combined with the serrated turbulence function, force the solution to diffuse and cover the entire membrane surface, eliminating flow dead zones and short-circuit flow, and significantly improving ion migration efficiency and current efficiency.

[0014] Furthermore, the salt solution storage tank, acid solution storage tank, alkali solution storage tank, and polar solution storage tank have the same structure and are connected to a drain pipe at the bottom. A valve is connected to the drain pipe to control the opening and closing of the drain pipe.

[0015] Furthermore, the front surface of the working box is equipped with a touch screen for controlling the switching on and off of the DC regulated power supply, setting voltage, current, and time parameters, and displaying data.

[0016] Before the experiment, the salt solution to be treated was added to the salt solution storage tank, the dilute acid solution to the acid solution storage tank, the dilute alkali solution to the alkali solution storage tank, and the dilute sodium sulfate electrode liquid to the electrode liquid storage tank. The working time, current, and voltage parameters were set via the touchscreen. Four peristaltic pumps were started, and the solution flowed through the suction pipe, peristaltic pumps, pipeline buffer, intermediate pipe, and inlet channel into the corresponding compartment. The solution flowed upwards along the channel groove, expelling internal air bubbles. A DC regulated power supply powered the anode and cathode electrode plates. Bipolar membrane water dissociation and ion migration reactions occurred within the stacked membrane stack, converting the salt solution into acid and alkali solutions, which were enriched in the acid and alkali chamber mesh plates, respectively. The remaining solution was discharged through the outlet channel and flowed back to the salt solution storage tank via the outlet pipe, forming a stable closed loop. During the experiment, the touchscreen monitored and displayed the operating parameters in real time. After the experiment, the DC regulated power supply was turned off first, then the peristaltic pumps were stopped, and the valve at the bottom of the storage tank was opened to discharge the waste liquid, completing the experiment.

[0017] Compared with existing technologies, this multifunctional bipolar membrane electrodialysis device has the following advantages: 1. The flow channel is equipped with a transverse staggered flow guide plate and a sawtooth turbulence structure to force solution disturbance and diffusion, prolong the flow time of the solution in the flow channel, cover the entire membrane surface, eliminate flow dead zones and short-circuit current, and greatly improve ion migration efficiency and current efficiency. 2. Integrated intelligent control: The PLC module, combined with a touch screen, enables precise regulation and real-time monitoring of voltage, current, flow rate, and running time. It is simple and convenient to operate, meeting the high-precision experimental needs of the laboratory. 3. The acid, salt, and alkali compartments are designed with bottom inlet and top outlet liquid distribution at the same height. The solution fills the membrane stack from bottom to top, completely expelling internal air bubbles and ensuring uniform electric field distribution and stable reaction. 4. The peristaltic pump outlet is connected to a cylindrical pipeline buffer, which effectively eliminates pump body pulsation flow, makes the membrane stack feed flow stable and uniform, avoids concentration polarization caused by flow fluctuations, and improves the repeatability of experimental data. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of this multifunctional bipolar membrane electrodialysis device.

[0019] Figure 2 This is a schematic diagram of the internal structure of the working box.

[0020] Figure 3 This is an assembly diagram of a pipeline buffer.

[0021] Figure 4 This is a longitudinal sectional view of a stacked membrane assembly.

[0022] Figure 5 This is a cross-sectional view of a stacked membrane assembly.

[0023] Figure 6 This is a schematic diagram of the structure of the acid chamber frame plate.

[0024] In the diagram, 1. Working chamber; 2. Stacked membrane assembly; 21. Anode electrode plate; 22. Left electrode chamber frame plate; 23. First bipolar membrane; 24. Acid chamber frame plate; 25. Anion exchange membrane; 26. Salt chamber frame plate; 27. Cation exchange membrane; 28. Alkali chamber frame plate; 29. ​​Second bipolar membrane; 210. Right electrode chamber frame plate; 211. Cathode electrode plate; 3. Salt solution storage tank; 4. Acid solution storage tank; 5. Alkali solution storage tank; 6. Electrode solution storage tank; 7. Peristaltic pump; 8. DC regulated power supply; 9. PLC module; 10. Pipeline buffer; 11. Inlet channel; 12. Outlet channel; 13. Channel groove; 14. Drain plate; 15. Serrated edge; 16. Drain pipe; 17. Valve; 18. Touch screen; 31. Suction pipe; 32. Intermediate pipe; 33. Outlet pipe. Detailed Implementation

[0025] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0026] like Figure 1 , Figure 2 , Figure 3As shown, this multifunctional bipolar membrane electrodialysis device includes a working chamber 1, a stacked membrane assembly 2, a brine storage tank 3, an acid storage tank 4, an alkali storage tank 5, an electrode liquid storage tank 6, and four peristaltic pumps 7. The four peristaltic pumps 7 are fixed inside the working chamber 1. The working chamber 1 also contains a DC regulated power supply 8 and a PLC module 9 that controls the start and stop of the peristaltic pumps 7 and their voltage and current output. The stacked membrane assembly 2 is fixed at the front end of the working chamber 1. The stacked membrane assembly 2 includes, from left to right, an anode electrode plate 21, a left electrode chamber frame plate 22, a first bipolar membrane 23, an acid chamber frame plate 24, an anion exchange membrane 25, and a brine electrode plate 26. The system includes a frame plate 26, a cation exchange membrane 27, an alkali frame plate 28, a second bipolar membrane 29, a right-side frame plate 210, and a cathode electrode plate 211. The left-side frame plate 22, acid frame plate 24, salt frame plate 26, alkali frame plate 28, and right-side frame plate 210 are each provided with an inlet channel 11 and an outlet channel 12. The inlets of the four peristaltic pumps 7 are connected to the bottom of the corresponding storage tanks through a suction pipe 31. The outlets of the peristaltic pumps 7 are connected to a pipeline buffer 10. The pipeline buffer 10 is connected to the inlet channel 11 through an intermediate pipe 32. The outlet channel 12 is connected to an outlet pipe 33 that is connected to the upper port of the corresponding storage tank.

[0027] like Figure 6 As shown, the left electrode chamber frame plate 22, acid chamber frame plate 24, salt chamber frame plate 26, alkali chamber frame plate 28, and right electrode chamber frame plate 210 are all square flat plates with a flow channel groove 13 between the liquid inlet channel 11 and the liquid outlet channel 12. The flow channel groove 13 is provided with transversely staggered guide plates 14, and the lower end face of the guide plate 14 has a row of serrations 15.

[0028] The staggered spacing between adjacent drainage plates 14 is 3mm to 8mm, and the serrations 15 at the lower end of the drainage plate 14 are isosceles serrations 15 with a depth of 0.5mm to 2mm.

[0029] like Figure 4 , Figure 5 As shown, the left electrode chamber frame plate 22 and the right electrode chamber frame plate 210 share a common inlet channel 11 and outlet channel 12. This simplifies the electrode liquid circulation pipeline structure and reduces the risk of leakage. The outlet channels 12 of the acid chamber frame plate 24, salt chamber frame plate 26, and alkali chamber frame plate 28 are located at the same height at the upper end of the stacked membrane stack assembly 2, while the inlet channels 11 of the acid chamber frame plate 24, salt chamber frame plate 26, and alkali chamber frame plate 28 are located at the same height at the lower end of the stacked membrane stack assembly 2. This forms a bottom-in, top-out full-liquid distribution structure, completely eliminating air bubbles within the membrane stack and ensuring uniform solution filling.

[0030] The pipeline buffer 10 is a cylinder closed at both ends, with the upper and lower ends serving as connection points. The pipeline buffer 10 continuously eliminates the pulsation of the peristaltic pump 7, ensuring stable flow within the flow channel 13.

[0031] The stacked membrane assembly 2 is bolted on, and the membranes are tightly attached to both sides of the chamber frame mesh plate. The solution flows in the flow channel 13. The transversely staggered flow guide plates 14, combined with the turbulence function of the sawtooth 15, force the solution to diffuse and cover the entire membrane surface, eliminate flow dead zones and short-circuit flow, and greatly improve ion migration efficiency and current efficiency.

[0032] The salt solution storage tank 3, acid solution storage tank 4, alkali solution storage tank 5, and polar solution storage tank 6 have the same structure and are connected to a drain pipe 16 at the bottom. A valve 17 is connected to the drain pipe 16 to control its opening and closing. This is used to quickly discharge waste liquid after the experiment, facilitating device cleaning.

[0033] The anode electrode plate 21 and cathode electrode plate 211 are clamped and fixed to the front end of the working chamber 1 by bolts. The anode electrode plate 21 and cathode electrode plate 211 are connected to the DC regulated power supply 8 through wires to provide a stable DC electric field for the electrodialysis reaction. The front surface of the working chamber 1 is provided with a touch screen 18 for controlling the on and off of the DC regulated power supply 8, setting voltage, current, and time parameters, and displaying data.

[0034] Working process: Before the experiment, the salt solution to be treated is added to the salt solution storage tank 3, the acid solution storage tank 4 is added to the acid solution storage tank 4, the alkali solution storage tank 5 is added to the alkali solution storage tank 5, and the polar solution storage tank 6 is added to the dilute sodium sulfate polar solution. The working time, current, and voltage parameters are set through the touch screen 18, and the four peristaltic pumps 7 are started. The solution enters the corresponding compartment through the suction pipe 31, the peristaltic pumps 7, the pipeline buffer 10, the intermediate pipe 32, and the inlet channel 11. The solution flows upward along the flow channel 13, expelling internal air bubbles. The DC regulated power supply 8 supplies power to the anode electrode plate 21 and the cathode electrode plate 211. Bipolar membrane water dissociation and ion migration reactions occur in the stacked membrane stack assembly 2. The salt solution is converted into acid and alkali solutions in the membrane stack and enriched in the acid chamber frame plate 24 and the alkali chamber frame plate 28, respectively. The remaining solution is discharged through the outlet channel 12 and flows back to the salt solution storage tank 3 through the outlet pipe 33, forming a stable closed loop. During the experiment, the touch screen 18 monitors and displays the operating parameters in real time. After the experiment, the DC regulated power supply 8 is turned off first, then the peristaltic pump 7 is stopped, and the valves 17 at the bottom of each storage tank are opened to discharge the waste liquid, thus completing the experiment.

[0035] The electrode fluid provides a stable, low-resistance, and corrosion-resistant conductive environment for the electrodes, safely introducing the electric field into the membrane stack while protecting the electrodes from corrosion and harmful side reactions. The electrode fluid does not participate in the main reaction that separates the salt solution into acid and alkali solutions; it only establishes and stabilizes the electric field. Before startup, add sodium sulfate solution to the electrode fluid reservoir 6 and close valve 17. Start the electrode fluid peristaltic pump 7 to simultaneously fill the left electrode chamber frame plate 22 and the right electrode chamber frame plate 210 with the electrode fluid, purge air, and form a stable circulation loop. After energization, the electrode fluid provides a low-resistance conductive path, and electrochemical reactions occur on the electrode surface. Electron transfer forms a stable DC electric field, driving water dissociation and ion migration within the membrane stack.

[0036] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A multifunctional bipolar membrane electrodialysis device, comprising a working chamber (1), a stacked membrane assembly (2), a brine storage tank (3), an acid storage tank (4), an alkali storage tank (5), an electrode liquid storage tank (6), and four peristaltic pumps (7), characterized in that, Four peristaltic pumps (7) are fixed inside the working chamber (1). The working chamber (1) is also fixed with a DC regulated power supply (8) and a PLC module (9) for controlling the start and stop of the peristaltic pumps (7) and the voltage and current output. The stacked membrane assembly (2) is fixed at the front end of the working chamber (1). The stacked membrane assembly (2) includes an anode electrode plate (21), a left electrode chamber frame plate (22), a first bipolar membrane (23), an acid chamber frame plate (24), an anion exchange membrane (25), a salt chamber frame plate (26), a cation exchange membrane (27), an alkali chamber frame plate (28), a second bipolar membrane (29), a right electrode chamber frame plate (210), and a cathode electrode plate (211). The left electrode chamber frame plate (22), acid chamber frame plate (24), salt chamber frame plate (26), alkali chamber frame plate (28), and right electrode chamber frame plate are stacked together from left to right. (210) Each is provided with an inlet channel (11) and an outlet channel (12). The inlets of the four peristaltic pumps (7) are connected to the bottom of the corresponding storage tank through the suction pipe (31). The outlet of the peristaltic pump (7) is connected to a pipeline buffer (10). The pipeline buffer (10) is connected to the inlet channel (11) through the intermediate pipe (32). The outlet channel (12) is connected to an outlet pipe (33) connected to the upper port of the corresponding storage tank. The left pole chamber frame plate (22), acid chamber frame plate (24), salt chamber frame plate (26), alkali chamber frame plate (28), and right pole chamber frame plate (210) are all square flat plates and have a channel groove (13) between the inlet channel (11) and the outlet channel (12). The channel groove (13) is provided with a horizontally staggered guide plate (14). The lower end of the guide plate (14) has a row of serrations (15).

2. The multifunctional bipolar membrane electrodialysis device according to claim 1, characterized in that, The staggered spacing between adjacent drainage plates (14) is 3mm to 8mm.

3. The multifunctional bipolar membrane electrodialysis device according to claim 1, characterized in that, The serrations (15) at the lower end of the diversion plate (14) are isosceles serrations (15), and the depth of the serrations (15) is 0.5mm to 2mm.

4. The multifunctional bipolar membrane electrodialysis device according to claim 1, characterized in that, The left polar chamber frame plate (22) and the right polar chamber frame plate (210) share a liquid inlet channel (11) and a liquid outlet channel (12).

5. The multifunctional bipolar membrane electrodialysis device according to claim 1, characterized in that, The liquid outlet channels (12) of the acid chamber frame plate (24), salt chamber frame plate (26), and alkali chamber frame plate (28) are located at the same height at the upper end of the stacked membrane assembly (2), and the liquid inlet channels (11) of the acid chamber frame plate (24), salt chamber frame plate (26), and alkali chamber frame plate (28) are located at the same height at the lower end of the stacked membrane assembly (2).

6. The multifunctional bipolar membrane electrodialysis device according to claim 1, characterized in that, The pipeline buffer (10) is a cylinder closed at both ends, with the upper and lower ends of the cylinder being the connecting ends.

7. The multifunctional bipolar membrane electrodialysis device according to claim 1, characterized in that, The anode electrode plate (21) and cathode electrode plate (211) are clamped and fixed to the front end of the working box (1) by bolts, and the anode electrode plate (21) and cathode electrode plate (211) are connected to the DC regulated power supply (8) by wires.

8. The multifunctional bipolar membrane electrodialysis device according to claim 1, characterized in that, The salt solution storage tank (3), acid solution storage tank (4), alkali solution storage tank (5), and polar solution storage tank (6) have the same structure and are connected to a drain pipe (16) at the bottom. A valve (17) is connected to the drain pipe (16) to control the opening and closing of the drain pipe (16).

9. The multifunctional bipolar membrane electrodialysis device according to any one of claims 1 to 8, characterized in that, The front surface of the working box (1) is provided with a touch screen (18) for controlling the on / off of the DC regulated power supply (8), setting voltage, current, time parameters and displaying data.

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