Electrodialysis system

Abstract

The utility model provides a kind of electrodialysis system, including electrodialysis device, and two anolyte circulating tanks and two catholyte circulating tanks, the two anolyte circulating tanks and two catholyte circulating tanks are used as operating anolyte circulating tank and spare anolyte circulating tank respectively, and operating catholyte circulating tank and spare catholyte circulating tank, so that when anolyte switching, electrodialysis device does not need to be stopped, thereby improve lithium extraction efficiency, and avoid the interruption of lithium product entire production process, so as to ensure the yield of lithium product.

Description

Technical Field

[0001] This utility model relates to the field of electrodialysis technology, and specifically to an electrodialysis system that does not shut down during electrode switching. Background Technology

[0002] With the development of the new energy industry, the importance of lithium resources is becoming increasingly prominent. Electrodialysis technology has always been one of the representative lithium extraction processes. Therefore, how to improve traditional electrodialysis technology is a research hotspot in the field of lithium extraction processes.

[0003] Magnesium- and lithium-containing brine from salt lakes or concentrated old brine from sun-dried salt fields has become a major source of lithium, and lithium is extracted using electrodialysis. Electrodialysis utilizes membrane separation principles. Under an applied DC electric field, lithium-containing brine from salt lakes passes through one or more stages of electrodialysis, using cation exchange membranes and anion exchange membranes in a cyclical process to concentrate lithium, remove impurities such as silicon and boron, and then add sodium carbonate to precipitate and produce lithium carbonate. Electrodialysis offers advantages such as high magnesium-lithium separation efficiency, strong operability, good production stability, low cost, low freshwater consumption, and clean, pollution-free operation, enabling the comprehensive utilization of lithium, boron, and potassium resources from salt lakes.

[0004] Currently, in the traditional electrodialysis method for lithium extraction, the electrode solution (i.e., the solution in the anode and cathode chambers) becomes unsuitable for continued use due to various reasons during the operation of the electrodialysis unit and needs to be replaced periodically to ensure the normal operation of the subsequent lithium extraction process. However, replacing the electrode solution means shutting down the electrodialysis unit, which prolongs the lithium extraction cycle and reduces extraction efficiency. In addition, frequent shutdowns can force the upstream and downstream processes of the electrodialysis unit to stop, thereby affecting the entire production process and resulting in reduced lithium production and economic losses.

[0005] Therefore, there is an urgent need for a technical solution that can solve the above-mentioned problems in the existing technology. Utility Model Content

[0006] In view of the above problems, this utility model provides an electrodialysis system that can operate without stopping during electrode switching, thereby achieving higher efficiency in lithium extraction, reducing equipment damage caused by frequent shutdowns, and lowering maintenance costs.

[0007] According to one aspect of the present invention, an electrodialysis system is provided, the electrodialysis system comprising:

[0008] An electrodialysis apparatus, comprising an anode chamber, a cathode chamber, and an intermediate chamber, wherein the intermediate chamber contains an ion exchange membrane assembly, the anode chamber includes an anolyte inlet and an anolyte outlet, and the cathode chamber includes a catholyte inlet and a catholyte outlet;

[0009] The first anolyte circulation tank and the second anolyte circulation tank are respectively connected to the anolyte circulation pump via the first anolyte outlet valve and the second anolyte outlet valve. The anolyte circulation pump is connected to the anolyte inlet of the electrodialysis device, and the first anolyte circulation tank and the second anolyte circulation tank are respectively connected to the anolyte outlet of the electrodialysis device via the first anolyte reflux valve and the second anolyte reflux valve.

[0010] The first cathode liquid circulation tank and the second cathode liquid circulation tank are respectively connected to the cathode liquid circulation pump via the first cathode liquid outlet valve and the second cathode liquid outlet valve. The cathode liquid circulation pump is connected to the cathode liquid inlet of the electrodialysis device, and the first cathode liquid circulation tank and the second cathode liquid circulation tank are respectively connected to the cathode liquid outlet of the electrodialysis device via the first cathode liquid reflux valve and the second cathode liquid reflux valve.

[0011] The electrodialysis system includes a first state and a second state that can be switched between each other. In the first state, only the first anolyte circulation tank is connected to the anolyte inlet and anolyte outlet of the electrodialysis device; in the second state, only the second anolyte circulation tank is connected to the anolyte inlet and anolyte outlet of the electrodialysis device.

[0012] The electrodialysis system also includes a third state and a fourth state that can be switched between each other. In the third state, only the first catholyte circulation tank is connected to the catholyte inlet and catholyte outlet of the electrodialysis device; in the fourth state, only the second catholyte circulation tank is connected to the catholyte inlet and catholyte outlet of the electrodialysis device.

[0013] In this way, when the anolyte needs to be replaced, the system can switch from the operating first anolyte circulation tank to the standby second anolyte circulation tank, and vice versa, without stopping the electrodialysis unit. Similarly, when the catholyte needs to be replaced, the system can switch from the operating first catholyte circulation tank to the standby second catholyte circulation tank, and vice versa, without stopping the electrodialysis unit.

[0014] In the electrodialysis system of this invention, two anolyte circulation tanks and two catholyte circulation tanks are set up, which are used as the operating anolyte circulation tank and the standby anolyte circulation tank, as well as the operating catholyte circulation tank and the standby catholyte circulation tank, respectively. This eliminates the need to shut down the electrodialysis device when switching between the electrodes, which improves the lithium extraction efficiency and avoids interruption of the entire lithium production process, thereby ensuring the output of lithium products. Attached Figure Description

[0015] The advantages and features of this utility model will now be described in detail with reference to the accompanying drawings. In the drawings, the components are not necessarily drawn to scale, and:

[0016] Figure 1 A schematic diagram of an electrodialysis system according to the present invention is shown;

[0017] Figure 2 A schematic diagram showing the connection of the controller and the delay device in an electrodialysis system according to one embodiment of the present invention is shown.

[0018] It should be understood that the accompanying drawings are for illustrative purposes only and should not be considered as limiting the present invention. Detailed Implementation

[0019] The electrodialysis system of this invention includes:

[0020] An electrodialysis apparatus, comprising an anode chamber, a cathode chamber, and an intermediate chamber, wherein the intermediate chamber contains an ion exchange membrane assembly, the anode chamber includes an anolyte inlet and an anolyte outlet, and the cathode chamber includes a catholyte inlet and a catholyte outlet;

[0021] The first anolyte circulation tank and the second anolyte circulation tank are respectively connected to the anolyte circulation pump via the first anolyte outlet valve and the second anolyte outlet valve. The anolyte circulation pump is connected to the anolyte inlet of the electrodialysis device, and the first anolyte circulation tank and the second anolyte circulation tank are respectively connected to the anolyte outlet of the electrodialysis device via the first anolyte reflux valve and the second anolyte reflux valve.

[0022] The first cathode liquid circulation tank and the second cathode liquid circulation tank are respectively connected to the cathode liquid circulation pump via the first cathode liquid outlet valve and the second cathode liquid outlet valve. The cathode liquid circulation pump is connected to the cathode liquid inlet of the electrodialysis device, and the first cathode liquid circulation tank and the second cathode liquid circulation tank are respectively connected to the cathode liquid outlet of the electrodialysis device via the first cathode liquid reflux valve and the second cathode liquid reflux valve.

[0023] The electrodialysis system includes a first state and a second state that can be switched between each other. In the first state, the first anolyte circulation tank is connected to the anolyte inlet and anolyte outlet of the electrodialysis device. In the second state, the second anolyte circulation tank is connected to the anolyte inlet and anolyte outlet of the electrodialysis device.

[0024] The electrodialysis system also includes a third state and a fourth state that can be switched between each other. In the third state, the first catholyte circulation tank is connected to the catholyte inlet and catholyte outlet of the electrodialysis device. In the fourth state, the second catholyte circulation tank is connected to the catholyte inlet and catholyte outlet of the electrodialysis device.

[0025] In the electrodialysis device of this invention, the intermediate chamber includes a feed inlet and an outlet. The inlet introduces the lithium-containing solution to be treated (e.g., magnesium- and lithium-containing brine from salt lakes or concentrated old brine from sun-dried salt fields) into the ion exchange module. The desalinated solution and concentrated solution produced by membrane separation are discharged from the intermediate chamber (i.e., discharged from the ion exchange membrane module) through their respective outlets. Since the improvement of this invention over the prior art does not lie in the intermediate chamber and the ion exchange membrane module, and the intermediate chamber and the ion exchange membrane module can be existing products of the prior art, this specification will not provide further explanation of these two parts.

[0026] According to a preferred embodiment of this utility model, the electrodialysis system further includes a gas source, which can be a fan for supplying air, or a gas storage tank with a feeding device for supplying gas, such as an inert gas like nitrogen. The first anolyte circulation tank is connected to the gas source via a first anolyte tank inlet pipe, the second anolyte circulation tank is connected to the gas source via a second anolyte tank inlet pipe, the first catholyte circulation tank is connected to the gas source via a first catholyte tank inlet pipe, and the second catholyte circulation tank is connected to the gas source via a second catholyte tank inlet pipe. During electrodialysis, chlorine gas is generated in the anolyte circulation tank. By supplying gas to the anolyte circulation tank from the gas source, the generated chlorine gas can be purged, thereby reducing the chlorine content in the anolyte circulation. Simultaneously, hydrogen gas is generated in the catholyte circulation tank. By supplying gas to the catholyte circulation tank from the gas source, the hydrogen content in the catholyte circulation can be reduced, preventing explosion.

[0027] According to a preferred embodiment of the present invention, the electrodialysis system further includes an airflow meter, which is installed at the air outlet of the gas source. The airflow meter can be used to monitor the flow rate and velocity of the gas supplied by the gas source.

[0028] According to a preferred embodiment of this utility model, the electrodialysis system further includes a storage tank. The outlet of the storage tank is connected to the inlet of the delivery pump. The first anolyte circulation tank, the second anolyte circulation tank, the first catholyte circulation tank, and the second catholyte circulation tank are respectively connected to the outlet of the delivery pump via a first anolyte tank inlet valve, a second anolyte tank inlet valve, a first catholyte tank inlet valve, and a second catholyte tank inlet valve. The storage tank can replenish the backup liquid to each electrodialysis tank at any time.

[0029] According to a preferred embodiment of the present invention, the first anolyte circulation tank, the second anolyte circulation tank, the first catholyte circulation tank, and the second catholyte circulation tank are each equipped with a level gauge. Advantageously, the level gauge can detect the liquid level in the anolyte circulation tank and the catholyte circulation tank, thereby indicating whether the liquid in the anolyte circulation tank and the catholyte circulation tank has been filled to the required level, or indicating that the liquid level in the anolyte circulation tank and the catholyte circulation tank is lower than the required level, and issuing a warning.

[0030] According to a preferred embodiment of this utility model, the electrodialysis system further includes a controller, which is electrically connected to the first anolyte outlet valve, the first anolyte return valve, the second anolyte outlet valve, the second anolyte return valve, the first catholyte outlet valve, the first catholyte return valve, the second catholyte outlet valve, and the second catholyte return valve, respectively. In this case, if it is necessary to switch the electrode solution, the controller controls the corresponding outlet valve and return valve to open and close, thereby realizing automatic switching of the electrode solution.

[0031] According to a preferred embodiment of this utility model, the electrodialysis system further includes a controller, which is electrically connected to the level gauge, the first anolyte tank feed valve, the second anolyte tank feed valve, the first catholyte tank feed valve, and the second catholyte tank feed valve. By controlling the opening of the corresponding feed valves, the automatic filling of the electrode circulation tanks can be achieved. Simultaneously, the level gauge can send information about the liquid level in the corresponding electrode circulation tank to the controller to indicate whether the liquid levels in the anolyte and catholyte circulation tanks have reached the required levels for use.

[0032] According to a preferred embodiment of the present invention, the electrodialysis system further includes a controller, which is electrically connected to the air volume meter and the gas source. Advantageously, by obtaining the amount of gas supplied by the gas source from the air volume meter, the controller can control the opening and closing of the corresponding feed valve, outlet valve, and reflux valve, thereby achieving automatic switching of the electrolytic liquid.

[0033] According to a preferred embodiment of the present invention, the electrodialysis system further includes a delay device connected to the controller and electrically connected to the first anolyte outlet valve, the first anolyte return valve, the second anolyte outlet valve, the second anolyte return valve, the first catholyte outlet valve, the first catholyte return valve, the second catholyte outlet valve, and the second catholyte return valve, respectively. Advantageously, by setting the delay device, the outlet valve of the operating electrode liquid circulation tank can be delayed in closing, thereby preventing the circulation pump from running dry, and the return valve of the electrode liquid circulation tank to be switched (the standby electrode liquid circulation tank) can be delayed in opening, thereby ensuring that the waste electrode liquid is completely discharged into the original electrode liquid tank and does not contaminate the electrode liquid circulation tank to be replaced.

[0034] According to a preferred embodiment of the present invention, the first anolyte circulation tank, the second anolyte circulation tank, the first catholyte circulation tank, and the second catholyte circulation tank are each equipped with a drain valve. Advantageously, the first anolyte circulation tank, the second anolyte circulation tank, the first catholyte circulation tank, and the second catholyte circulation tank can be quickly emptied of their liquids by opening their respective drain valves.

[0035] In this utility model, unless otherwise explicitly stated, the term "connection" should be broadly understood to include both fixed connections and detachable connections, and may also refer to direct connections or indirect connections through intermediate elements.

[0036] In this article, "switching" should be understood as a transition from one state to another, where the two states do not exist simultaneously. For example, switching an electrodialysis system from the first anolyte circulation tank to the second anolyte circulation tank means that the first anolyte circulation tank is disconnected from the electrodialysis device, while the second anolyte circulation tank is connected to the electrodialysis device and enters the operating state, and vice versa. Similarly, switching an electrodialysis system from the first catholyte circulation tank to the second catholyte circulation tank means that the first catholyte circulation tank is disconnected from the electrodialysis device, while the second catholyte circulation tank is connected to the electrodialysis device and enters the operating state, and vice versa. However, it should be understood that an electrodialysis system can be in the first and third states simultaneously, or in the first and fourth states simultaneously, or in the second and third states simultaneously, or in the second and fourth states simultaneously.

[0037] The components of this utility model can be made of polyvinyl chloride plastic and fiberglass, etc., using known manufacturing methods, or directly using existing commercially available equipment.

[0038] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. However, it should be noted that the scope of the present invention is not limited to the embodiments shown in the drawings.

[0039] Figure 1 A schematic diagram of the electrodialysis system according to the present invention is shown. Figure 2 A schematic diagram showing the connection of the controller and the delay device in an electrodialysis system according to one embodiment of the present invention is shown.

[0040] like Figure 1 As shown, the electrodialysis system 1 includes an electrodialysis device 3, a first anolyte circulation tank 11, a second anolyte circulation tank 12, a first catholyte circulation tank 21, and a second catholyte circulation tank 22. Optionally, the electrodialysis system 1 also includes a storage tank 4 and a gas source 5.

[0041] The electrodialysis apparatus 3 includes an anolyte inlet 31 and an anolyte outlet 32 ​​on the anode side, and a catholyte inlet 33 and a catholyte outlet 34 on the cathode side. It is understood that the electrodialysis apparatus 3 also includes an intermediate chamber (not shown in detail) and an ion exchange membrane assembly within it. The feed solution to be treated (e.g., particularly magnesium- and lithium-containing brine from salt lakes or concentrated old brine from sun-dried salt fields) enters the membrane assembly for treatment through the inlet of the intermediate chamber. The desalinated solution and concentrated solution produced after treatment are respectively discharged from the intermediate chamber (i.e., discharged from the ion exchange membrane assembly) through their respective outlets. On the anode side, the anolyte enters the electrodialysis apparatus 3 through the anolyte inlet 31 from either the first anolyte circulation tank 11 or the second anolyte circulation tank 12. After electrolysis in the anode chamber, it exits the electrodialysis apparatus 3 from the anolyte outlet 32. On the cathode side, the catholyte enters the electrodialysis apparatus 3 through the catholyte inlet 33 from either the first catholyte circulation tank 21 or the second catholyte circulation tank 22. After electrolysis in the cathode chamber, it exits the electrodialysis apparatus 3 from the catholyte outlet 32.

[0042] The first anolyte circulation tank 11 and the second anolyte circulation tank 12 are respectively connected to the anolyte circulation pump 9 via the first anolyte outlet valve 11-3 and the second anolyte outlet valve 12-3. The anolyte circulation pump 9 is then connected to the anolyte inlet 31 of the electrodialysis device 3, so that when the first anolyte outlet valve 11-3 is opened, the anolyte from the first anolyte circulation tank 11 can be pumped into the electrodialysis device 3, and when the second anolyte outlet valve 12-3 is opened, the anolyte from the second anolyte circulation tank 12 can be pumped into the electrodialysis device 3. In addition, the first anolyte circulation tank 11 and the second anolyte circulation tank 12 are respectively connected to the anolyte outlet 32 ​​of the electrodialysis device 3 via the first anolyte reflux valve 11-2 and the second anolyte reflux valve 12-2, so that when the first anolyte reflux valve 11-2 is opened, the anolyte flows back from the electrodialysis device 3 to the first anolyte circulation tank 11, and when the second anolyte reflux valve 12-2 is opened, the anolyte flows back from the electrodialysis device 3 to the second anolyte circulation tank 12.

[0043] The first cathode liquid circulation tank 21 and the second cathode liquid circulation tank 22 are respectively connected to the cathode liquid circulation pump 10 via the first cathode liquid outlet valve 21-3 and the second cathode liquid outlet valve 22-3. The cathode liquid circulation pump 10 is then connected to the cathode liquid inlet 33 of the electrodialysis device 3, so that when the first cathode liquid outlet valve 21-3 is opened, the cathode liquid from the first cathode liquid circulation tank 21 can be pumped into the electrodialysis device 3, and when the second cathode liquid outlet valve 22-3 is opened, the cathode liquid from the second cathode liquid circulation tank 22 can be pumped into the electrodialysis device 3. In addition, the first catholyte circulation tank 21 and the second catholyte circulation tank 22 are respectively connected to the catholyte outlet 34 of the electrodialysis device 3 via the first catholyte reflux valve 21-2 and the second catholyte reflux valve 22-2, so that when the first catholyte reflux valve 21-2 is opened, the catholyte flows back from the electrodialysis device 3 to the first catholyte circulation tank 21, and when the second catholyte reflux valve 22-2 is opened, the catholyte flows back from the electrodialysis device 3 to the second catholyte circulation tank 22.

[0044] Taking the first anolyte circulation tank 11 as being in operation and the second anolyte circulation tank 12 as being in standby mode as an example, when it is necessary to switch from the first anolyte circulation tank 11 to the second anolyte circulation tank 12, the second anolyte outlet valve 12-3 and the second anolyte return valve 12-2 are opened, connecting the second anolyte circulation tank 12 to the anolyte inlet 31 and the anolyte outlet 32 ​​of the electrodialysis device 3, thus entering the operation state. Meanwhile, the first anolyte outlet valve 11-3 and the first anolyte return valve 11-2 are closed, disconnecting the first anolyte circulation tank 11 from the anolyte inlet 31 and the anolyte outlet 32 ​​of the electrodialysis device 3, thus entering the standby state. In this way, the electrodialysis system switches from the first state to the second state. It should be understood that when it is necessary to switch from the second anolyte circulation tank 12 to the first anolyte circulation tank 11, the second anolyte circulation tank 12 is disconnected from the anolyte inlet 31 and anolyte outlet 32 ​​of the electrodialysis device 3 and enters a standby state, while the first anolyte circulation tank 11 is connected to the anolyte inlet 31 and anolyte outlet 32 ​​of the electrodialysis device 3 and enters an operating state. In this way, the electrodialysis system switches from the second state to the first state.

[0045] Taking the first catholyte circulation tank 21 as being in operation and the second catholyte circulation tank 22 as being in standby mode as an example, when it is necessary to switch from the first catholyte circulation tank 21 to the second catholyte circulation tank 22, the second catholyte outlet valve 22-3 and the second catholyte return valve 22-2 are opened, connecting the second catholyte circulation tank 22 to the catholyte inlet 33 and the catholyte outlet 34 of the electrodialysis device 3, thus entering the operation state. Meanwhile, the first catholyte outlet valve 21-3 and the first catholyte return valve 21-2 are closed, disconnecting the first catholyte circulation tank 21 from the catholyte inlet 33 and the catholyte outlet 34 of the electrodialysis device 3, thus entering the standby state. In this way, the electrodialysis system switches from the third state to the fourth state. It should be understood that when it is necessary to switch from the second catholyte circulation tank 22 to the first catholyte circulation tank 21, the second catholyte circulation tank 22 is disconnected from the catholyte inlet 33 and the catholyte outlet 34 of the electrodialysis device 3 and enters the standby state, while the first catholyte circulation tank 21 is connected to the catholyte inlet 33 and the catholyte outlet 34 of the electrodialysis device 3 and enters the operating state. In this way, the electrodialysis system switches from the fourth state to the third state.

[0046] This switching can be done manually or automatically. For example, the first anolyte outlet valve 11-3, the first anolyte return valve 11-2, the second anolyte outlet valve 12-3, and the second anolyte return valve 12-2 can be mechanical switching valves. Automatic switching will be described in detail below.

[0047] Optionally, the electrodialysis system 1 also includes a gas source 5, with the first anolyte circulation tank 11 connected to the gas source 5 via a first anolyte tank inlet pipe 11-4; the second anolyte circulation tank 12 connected to the gas source 5 via a second anolyte tank inlet pipe 12-4; the first catholyte circulation tank 21 connected to the gas source 5 via a first catholyte tank inlet pipe 21-4; and the second catholyte circulation tank 22 connected to the gas source 5 via a second catholyte tank inlet pipe 22-4. As operating time increases, chlorine gas produced by the chemical reaction of the solution under anolyte electrolysis will flow back into the anolyte circulation tank, resulting in chlorine gas being generated in the anolyte circulation tank, which can be harmful to human health and the environment. Supplying gas to the anolyte circulation tank through the gas source can reduce the chlorine content in the circulating anolyte. Similarly, the hydrogen produced by the chemical reaction of the solution under cathodic electrolysis will flow back into the cathodic liquid circulation tank, causing hydrogen to be generated in the cathodic liquid circulation tank. By supplying gas to the cathodic liquid circulation tank through a gas source, the hydrogen content in the cathodic liquid circulation can be reduced, preventing explosion.

[0048] Optionally, the electrodialysis system 1 may include an airflow meter 50, which is preferably located at the outlet of the gas source 5 to monitor the flow rate and / or velocity of the gas supplied by the gas source 5. The gas supply of the gas source 5 can be adjusted based on the chlorine concentration measured at the anolyte circulation tank and / or the hydrogen concentration measured at the catholyte circulation tank.

[0049] Optionally, the electrodialysis system 1 may further include a storage tank 4 for storing the electrode solution required for electrodialysis operation. The outlet of the storage tank 4 is connected to the inlet of the transfer pump 8, and the first anolyte circulation tank 11, the second anolyte circulation tank 12, the first catholyte circulation tank 21, and the second catholyte circulation tank 22 are respectively connected to the outlet of the transfer pump 8 via the first anolyte tank inlet valve 11-1, the second anolyte tank inlet valve 12-1, the first catholyte tank inlet valve 21-1, and the second catholyte tank inlet valve 22-1. Thus, the outlet tank 4 can selectively supply electrode solution to the first anolyte circulation tank 11, the second anolyte circulation tank 12, the first catholyte circulation tank 21, and the second catholyte circulation tank 22. For example, when the first anolyte tank inlet valve 11-1 is opened, the storage tank 4 pumps the electrode liquid to the first anolyte circulation tank 11 via the transfer pump 8; when the second anolyte tank inlet valve 12-1 is opened, the storage tank 4 pumps the electrode liquid to the second anolyte circulation tank 12 via the transfer pump 8; when the first catholyte tank inlet valve 21-1 is opened, the storage tank 4 pumps the electrode liquid to the first catholyte circulation tank 21 via the transfer pump 8; when the second catholyte tank inlet valve 22-1 is opened, the storage tank 4 pumps the electrode liquid to the second catholyte circulation tank 22 via the transfer pump 8. The first anolyte tank inlet valve 11-1, the second anolyte tank inlet valve 12-1, the first catholyte tank inlet valve 21-1, and the second catholyte tank inlet valve 22-1 can be mechanical switching valves or electromagnetic switching valves.

[0050] Optionally, the first anolyte circulation tank 11, the second anolyte circulation tank 12, the first catholyte circulation tank 21, and the second catholyte circulation tank 22 are each equipped with a level gauge 101. Advantageously, the level gauge 101 can detect the liquid level in the anolyte circulation tank and the catholyte circulation tank, and if the liquid level is too low, it indicates that the corresponding anolyte circulation tank needs to be replenished until the required liquid level is reached.

[0051] Optionally, the first anolyte circulation tank 11 is equipped with a first anolyte tank drain valve 11-5, the second anolyte circulation tank 12 is equipped with a second anolyte tank drain valve 12-5, the first catholyte circulation tank 21 is equipped with a first catholyte tank drain valve 21-5, and the second catholyte circulation tank 22 is equipped with a second catholyte tank drain valve 22-5. Preferably, the first anolyte tank drain valve 11-5, the second anolyte tank drain valve 12-5, the first catholyte tank drain valve 21-5, and the second catholyte tank drain valve 22-5 have the same structure and working principle, and can be collectively referred to as "drain valves". Taking the first anolyte circulation tank 11 as an example, when the first anolyte circulation tank 11 switches from the operating state to the standby state, the first anolyte tank drain valve 11-5 can be opened to quickly drain the anolyte in the first anolyte circulation tank 11 for refilling with new anolyte.

[0052] Preferably, the electrodialysis system 1 may include cleaning lines (not shown). The cleaning lines are connected to the first anolyte circulation tank 11, the second anolyte circulation tank 12, the first catholyte circulation tank 21, and the second catholyte circulation tank 22, and the corresponding circulation tanks are cleaned by supplying cleaning liquid.

[0053] Indicatively, Figure 2 An electrodialysis system according to one embodiment of the present invention is shown. For clarity, all components are shown schematically in a modular manner only.

[0054] Optionally, the electrodialysis system 1 also includes a controller 6, such as a programmable logic controller (PLC), for automatically switching between the first anolyte circulation tank 11 and the second anolyte circulation tank 12, and between the first catholyte circulation tank 21 and the second catholyte circulation tank 22. A PLC is a programmable memory known in industrial production that stores operating instructions internally and can control the switching of valves via digital or analog inputs / outputs.

[0055] In one embodiment of this utility model, the first anolyte tank inlet valve 11-1, the first anolyte reflux valve 11-2, the first anolyte outlet valve 11-3, the first anolyte tank drain valve 11-5, the second anolyte tank inlet valve 12-1, the second anolyte reflux valve 12-2, the second anolyte outlet valve 12-3, the second anolyte tank drain valve 12-5, the first cathode liquid tank inlet valve 21-1, the first cathode liquid reflux valve 21-2, the first cathode liquid outlet valve 21-3, the first cathode liquid tank drain valve 21-5, the second cathode liquid tank inlet valve 22-1, the second cathode liquid reflux valve 22-2, the second cathode liquid outlet valve 22-3, and the second cathode liquid tank drain valve 22-5 are all solenoid valves, and all are electrically connected to the controller 6. When a switching operation is required, the controller 6 outputs a voltage signal, energizing or de-energizing the corresponding solenoid valve, thereby opening or closing it.

[0056] Optionally, the air volume meter 50 and the liquid level gauge 101 are also connected to the controller 6. Advantageously, by acquiring information from the air volume meter 50 about the amount of gas supplied by the air source 5, or from the liquid level detected by the liquid level gauge 101, the controller 6 can control the opening and closing of the corresponding feed valve, discharge valve, and return valve, thereby achieving automatic switching of the polar liquid.

[0057] Optionally, the electrodialysis system 1 also includes a delay device 7, which may be part of the controller 6 or a separate component. It should be understood that the delay device contains a delay element, ensuring that the input signal reaches the output terminal after a certain period of time, thus achieving the delay function. The delay device 7 can be connected to the controller 6 and electrically connected to the first anolyte outlet valve 11-3, the first anolyte return valve 11-2, the second anolyte outlet valve 12-3, the second anolyte return valve 12-2, the first catholyte outlet valve 21-3, the first catholyte return valve 21-2, the second catholyte outlet valve 22-3, and the second catholyte return valve 22-2, respectively. By setting the delay device, during switching, the outlet valve of the operating electrode liquid circulation tank can be delayed in closing, thereby preventing the circulation pump from running dry, and the return valve of the electrode liquid circulation tank to be switched (the standby electrode liquid circulation tank) can be delayed in opening, thereby ensuring that the waste electrode liquid is completely discharged into the original electrode liquid tank and does not contaminate the electrode liquid circulation tank to be replaced.

[0058] For example, the process of switching from the first anolyte circulation tank 11 to the second anolyte circulation tank 12 is described below. The reverse switching is similar and will not be described in detail.

[0059] When the first anolyte circulation tank 11 is in operation, the first anolyte outlet valve 11-3 and the first anolyte return valve 11-2 of the first anolyte circulation tank 11 are open, and (optionally) the gas source 5 is working. The first anolyte circulation tank 11 is connected to the anolyte inlet 31 and the anolyte outlet 32 ​​of the electrodialysis device 3, while the second anolyte outlet valve 12-3 and the second anolyte return valve 12-2 of the second anolyte circulation tank 12 are closed.

[0060] When a switch from the first anolyte circulation tank 11 to the second anolyte circulation tank 12 needs to be performed according to the set switching cycle (e.g., 14 days), the controller 6 starts to perform the switching operation, opening the second anolyte outlet valve 12-3 of the second anolyte circulation tank 12. Preferably, after a delay of 5 seconds (adjustable), the first anolyte outlet valve 11-3 of the first anolyte circulation tank 11 is closed. After a delay of 15 minutes (adjustable), the first anolyte return valve 11-2 of the first anolyte circulation tank 11 is closed, and the second anolyte return valve 12-2 of the second anolyte circulation tank 12 is opened. Optionally, the gas source 5 stops working. At this point, the second anolyte outlet valve 12-3 and the second anolyte return valve 12-2 of the second anolyte circulation tank 12 are opened, and (optionally) the gas source 5 stops working. The second anolyte circulation tank 12 is connected to the anolyte inlet 31 and the anolyte outlet 32 ​​of the electrodialysis device 3 and enters the operating state, while the first anolyte outlet valve 11-3 and the first anolyte return valve 11-2 of the first anolyte circulation tank 11 are closed, and (optionally) the gas source 5 stops working.

[0061] After the first anolyte circulation tank 11 enters the standby state, the first anolyte tank drain valve 11-5 is opened to drain the anolyte inside. Then, the first anolyte tank feed valve 11-1 is opened to refill the first anolyte circulation tank 11 until the required liquid level is reached for the next switchover.

[0062] After the second anolyte outlet valve 12-3 is opened, the first anolyte outlet valve 11-3 of the first anolyte circulation tank 11 is closed after a certain delay to prevent the anolyte circulation pump 9 from running dry. Additionally, after the second anolyte outlet valve 12-3 is opened, the first anolyte return valve 11-2 of the first anolyte circulation tank 11 is closed after a certain delay to prevent stale anolyte from entering the newly switched second anolyte circulation tank 12.

[0063] For example, the process of switching from the first catholyte circulation tank 21 to the second catholyte circulation tank 22 is described below. The reverse switching is similar and will not be described in detail.

[0064] When the first cathode liquid circulation tank 21 is in operation, the first cathode liquid outlet valve 21-3 and the first cathode liquid return valve 21-2 of the first cathode liquid circulation tank 21 are open, and (optionally) the gas source 5 is working. The first cathode liquid circulation tank 21 is connected to the cathode liquid inlet 33 and the cathode liquid outlet 34 of the electrodialysis device 3, while the second cathode liquid outlet valve 22-3 and the second cathode liquid return valve 22-2 of the second cathode liquid circulation tank 22 are closed.

[0065] When the switching from the first cathode liquid circulation tank 21 to the second cathode liquid circulation tank 22 needs to be performed according to the set switching cycle (e.g., 14 days), the controller 6 starts to perform the switching operation, opening the second cathode liquid outlet valve 22-3 of the second cathode liquid circulation tank 22. Preferably, after a delay of 5 seconds (adjustable), the first cathode liquid outlet valve 11-3 of the first cathode liquid circulation tank 21 is closed. After a delay of 15 minutes (adjustable), the first cathode liquid return valve 21-2 of the first cathode liquid circulation tank 21 is closed, and the second cathode liquid return valve 22-2 of the second cathode liquid circulation tank 22 is opened. At this point, the second cathode liquid outlet valve 22-3 and the second cathode liquid return valve 22-2 of the second cathode liquid circulation tank 22 are opened, and (optionally) the gas source 5 is activated. The second cathode liquid circulation tank 22 is connected to the cathode liquid inlet 33 and the cathode liquid outlet 34 of the electrodialysis device 3 and enters the operating state, while the first cathode liquid outlet valve 21-3 and the first cathode liquid return valve 21-2 of the first cathode liquid circulation tank 21 are closed.

[0066] After the first cathode liquid circulation tank 21 enters the standby state, the first cathode liquid tank drain valve 21-5 is opened to drain the cathode liquid inside. Then, the first cathode liquid tank feed valve 21-1 is opened to refill the first cathode liquid circulation tank 21 until the required liquid level is reached for the next switchover.

[0067] After the second cathode liquid outlet valve 22-3 is opened, the first cathode liquid outlet valve 21-3 of the first cathode liquid circulation tank 21 is closed after a certain delay to prevent the anolyte circulation pump 10 from running dry. Additionally, after the second cathode liquid outlet valve 22-3 is opened, the first cathode liquid return valve 21-2 of the first cathode liquid circulation tank 21 is closed after a certain delay to prevent stale cathode liquid from entering the newly switched second cathode liquid circulation tank 22.

[0068] It should be understood that the aforementioned switching cycle and delay duration can be set as needed. Furthermore, the switching of the anolyte circulation tank and the catholyte circulation tank can be performed simultaneously or separately as needed. For example, the switching cycle of the anolyte circulation tank can be set to 7-14 days, while the switching cycle of the catholyte circulation tank can be set to 10-20 days.

[0069] Optionally, the electrodialysis system may be equipped with an anolyte switching button and a catholyte switching button, and the operator can actively start the switching operation by pressing the corresponding switching button.

[0070] While various preferred embodiments have been shown and described above, it will be apparent to those skilled in the art that modifications and variations may be made without departing from the scope of the present invention as defined in the appended claims.

Claims

1. An electrodialysis system, characterized in that, The electrodialysis system includes: An electrodialysis device, comprising an anode chamber, a cathode chamber, and an intermediate chamber, wherein the intermediate chamber contains an ion exchange membrane assembly, and the anode chamber includes an anolyte inlet and an anolyte outlet, and the cathode chamber includes a catholyte inlet and a catholyte outlet; The first anolyte circulation tank and the second anolyte circulation tank are respectively connected to the anolyte circulation pump via the first anolyte outlet valve and the second anolyte outlet valve. The anolyte circulation pump is connected to the anolyte inlet of the electrodialysis device, and the first anolyte circulation tank and the second anolyte circulation tank are respectively connected to the anolyte outlet of the electrodialysis device via the first anolyte reflux valve and the second anolyte reflux valve. The first cathode liquid circulation tank and the second cathode liquid circulation tank are respectively connected to the cathode liquid circulation pump via the first cathode liquid outlet valve and the second cathode liquid outlet valve. The cathode liquid circulation pump is connected to the cathode liquid inlet of the electrodialysis device, and the first cathode liquid circulation tank and the second cathode liquid circulation tank are respectively connected to the cathode liquid outlet of the electrodialysis device via the first cathode liquid reflux valve and the second cathode liquid reflux valve. The electrodialysis system includes a first state and a second state that can be switched between each other. In the first state, only the first anolyte circulation tank is connected to the anolyte inlet and anolyte outlet of the electrodialysis device; in the second state, only the second anolyte circulation tank is connected to the anolyte inlet and anolyte outlet of the electrodialysis device. The electrodialysis system also includes a third state and a fourth state that can be switched between each other. In the third state, only the first catholyte circulation tank is connected to the catholyte inlet and catholyte outlet of the electrodialysis device; in the fourth state, only the second catholyte circulation tank is connected to the catholyte inlet and catholyte outlet of the electrodialysis device.

2. The electrodialysis system according to claim 1, characterized in that, The electrodialysis system further includes a gas source, and the first anolyte circulation tank is connected to the gas source via a first anolyte tank inlet pipe, the second anolyte circulation tank is connected to the gas source via a second anolyte tank inlet pipe, the first catholyte circulation tank is connected to the gas source via a first catholyte tank inlet pipe, and the second catholyte circulation tank is connected to the gas source via a second catholyte tank inlet pipe.

3. The electrodialysis system according to claim 2, characterized in that, The electrodialysis system also includes an air volume meter, which is installed at the air outlet of the air source.

4. The electrodialysis system according to any one of claims 1-3, characterized in that, The electrodialysis system further includes a storage tank, the outlet of which is connected to the inlet of the delivery pump, and the first anolyte circulation tank, the second anolyte circulation tank, the first catholyte circulation tank, and the second catholyte circulation tank are respectively connected to the outlet of the delivery pump via the first anolyte tank feed valve, the second anolyte tank feed valve, the first catholyte tank feed valve, and the second catholyte tank feed valve.

5. The electrodialysis system according to claim 4, characterized in that, Each of the first anolyte circulation tank, the second anolyte circulation tank, the first catholyte circulation tank, and the second catholyte circulation tank is equipped with a level gauge.

6. The electrodialysis system according to any one of claims 1-3, characterized in that, The electrodialysis system also includes a controller, which is electrically connected to the first anolyte outlet valve, the first anolyte return valve, the second anolyte outlet valve, the second anolyte return valve, the first catholyte outlet valve, the first catholyte return valve, the second catholyte outlet valve, and the second catholyte return valve, respectively.

7. The electrodialysis system according to claim 5, characterized in that, The electrodialysis system also includes a controller, which is electrically connected to the level gauge, the first anolyte inlet valve, the second anolyte inlet valve, the first catholyte inlet valve, and the second catholyte inlet valve.

8. The electrodialysis system according to claim 3, characterized in that, The electrodialysis system also includes a controller, which is electrically connected to the air volume meter and the gas source.

9. The electrodialysis system according to claim 6, characterized in that, The electrodialysis system also includes a delay device, which is connected to the controller and electrically connected to the first anolyte outlet valve, the first anolyte return valve, the second anolyte outlet valve, the second anolyte return valve, the first catholyte outlet valve, the first catholyte return valve, the second catholyte outlet valve, and the second catholyte return valve, respectively.

10. The electrodialysis system according to any one of claims 1-3, characterized in that, Each of the first anolyte circulation tank, the second anolyte circulation tank, the first catholyte circulation tank, and the second catholyte circulation tank is equipped with a drain valve.

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