Efficient cathode electronic descaling system and descaling method

Abstract

The invention relates to an efficient cathode electron descaling system and descaling method, and the system comprises an electrode module which comprises a working anode, first cathodes disposed at two sides of the working anode, and second cathodes disposed at two sides of the working anode; the direct-current power supply is provided with a positive electrode and a negative electrode; the working anode is connected with the positive electrode, the two groups of first cathodes are connected in parallel and then selectively connected with the positive electrode and the negative electrode, and the two groups of second cathodes are connected in parallel and then selectively connected with the positive electrode and the negative electrode; and the first cathode and the second cathode are not connected with the anode at the same time. Shutdown disassembly is not needed, and scale layer prevention and removal in continuous operation are achieved; and physical coverage and chemical corrosion of hard scale to an electrode coating are reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrolysis, and relates to an electronic descaling system, in particular to a high-efficiency cathode electronic descaling system and a descaling method. Background Art

[0002] In conventional electrolysis of water, a reduction reaction occurs near the cathode (e.g., 2H2O+2e - →H2↑+2OH - ), generating a large amount of OH - ions, causing the local pH value to rise sharply (strong alkalinity). 2+ Mg 2+ In this environment, plasma forms insoluble precipitates (such as CaCO3 and Mg(OH)2), which adhere to the cathode surface as scale. Scale preferentially adheres to the cathode surface in the form of microcrystals, avoiding deposition within the pipes. Scale deposited on the cathode significantly impacts electrolysis efficiency and electrode life.

[0003] The Chinese invention patent with application number 202110561502.1 discloses a method for preparing ozone by electrolyzing water while maintaining the cathode online. The parallel-connected working anodes are connected to the positive pole of the working power supply, and the parallel-connected working cathodes are connected to the negative pole of the working power supply to prepare ozone. When sediment accumulates on the surface of the working cathode, the activity of the working cathode is maintained and restored by reversing the polarity by restoring the cathode. However, the above method generally adopts timed reversal descaling, which is affected by the uncertainty of the working time of the equipment. The equipment started at intervals will have poor descaling effect due to insufficient reversal time. In addition, the water quality (TDS) and water temperature in different regions are different, and the conditions for reversal descaling are also different. It is necessary to match the reversal time of different water qualities to more effectively improve the efficiency of ozone production and the descaling effect. Summary of the Invention

[0004] The purpose of the present invention is to provide a high-efficiency cathode electronic descaling system in order to overcome the deficiencies of the prior art.

[0005] To achieve the above object, the technical solution adopted by the present invention is: a high-efficiency cathode electronic descaling system, which includes:

[0006] An electrode module, the electrode module comprising a working anode, a first cathode disposed on both sides of the working anode, and a second cathode disposed on both sides of the working anode;

[0007] A DC power supply having a positive electrode and a negative electrode; the working anode is connected to the positive electrode, two groups of the first cathodes are connected in parallel and then alternatively connected to the positive electrode or the negative electrode, and two groups of the second cathodes are connected in parallel and then alternatively connected to the positive electrode or the negative electrode; the first cathode and the second cathode are not connected to the positive electrode at the same time.

[0008] Optimally, the two groups of the first cathodes are symmetrical about the working anode, and the two groups of the second cathodes are symmetrical about the working anode.

[0009] Furthermore, the two groups of the second cathodes and the two groups of the first cathodes are located in the same plane in a one-to-one correspondence, or the two groups of the second cathodes are located outside the two groups of the first cathodes.

[0010] Optimally, it also includes:

[0011] a constant current unit, the constant current unit being connected to the DC power supply;

[0012] A positive and negative polarity control unit, the positive and negative polarity control unit is connected to the constant current unit and the electrode module;

[0013] AD conversion unit, the AD conversion unit is connected to the constant current unit,

[0014] An MCU control unit, the MCU control unit being connected to the AD conversion unit and the positive and negative polarity control unit respectively;

[0015] A water flow rate sensor unit, the water flow rate sensor unit being connected to the MCU control unit;

[0016] A water temperature sensor unit, connected to the MCU control unit;

[0017] A storage unit connected to the MCU control unit;

[0018] A time crystal oscillator is connected to the MCU control unit.

[0019] Another object of the present invention is to provide a method for efficiently removing cathode electronic scale, comprising the following steps:

[0020] (a) Based on the water flow rate sensor, the system is activated when water is flowing;

[0021] (b) Entering the system operation state, the system enters the working mode, and the positive and negative electrodes produce ozone water through water electrolysis reaction;

[0022] (c) The MCU control unit reads whether there is an unfinished descaling program in the storage unit. If there is an unfinished descaling program, the descaling program will continue to be started; if there is no descaling program that needs to be started or the descaling program has been completed, the descaling program will continue to run.

[0023] Optimally, in step (b), whether to start the descaling program is determined based on the calculated scale accumulation on the cathode plates during operation.

[0024] Furthermore, in step (b), the scale deposition rate per unit time is calculated according to the following formula:

[0025]

[0026] The MCU control unit calculates the value M scale Add the accumulated ΔM to the storage unit; scale Divide it by the set reversal threshold, and when the value is an integer, the descaling process is started.

[0027] Due to the application of the above technical solution, the high-efficiency cathode electronic descaling system and descaling method of the present invention have the following effects:

[0028] (1) Automatic online descaling: No need to stop or disassemble the machine, preventing and removing scale during continuous operation;

[0029] (2) Extend electrode life: reduce the physical coverage and chemical corrosion of hard scale on the electrode coating;

[0030] (3) Maintaining stable electrolysis efficiency: Avoiding the decrease in current density, increased energy consumption and reduced ozone generation efficiency caused by scaling;

[0031] (4) Reduce maintenance costs: reduce the frequency of manual chemical cleaning and the consumption of special descaling agents. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic structural diagram of the high-efficiency cathode electronic descaling system of the present invention;

[0033] Figure 2 This is a flow chart of the high-efficiency cathode electronic descaling method of the present invention;

[0034] Figure 3 Schematic diagram of the switching between different modes of the high-efficiency cathode electronic descaling system of the present invention. DETAILED DESCRIPTION

[0035] The present invention will be further described below with reference to the embodiments shown in the accompanying drawings.

[0036] like Figure 1 The high-efficiency cathode electronic descaling system shown mainly includes an electrode module and a DC power supply.

[0037] Among them, the electrode module includes a working anode, a first cathode arranged on both sides of the working anode, and a second cathode arranged on both sides of the working anode; the DC power supply has a positive pole and a negative pole; the working anode is connected to the positive pole, and the two groups of first cathodes are connected in parallel and then selectively connected to the positive pole or the negative pole, and the two groups of second cathodes are connected in parallel and then selectively connected to the positive pole or the negative pole; the first cathode and the second cathode are not connected to the positive pole at the same time.

[0038] The two groups of first cathodes are symmetrical about the working anode, and the two groups of second cathodes are symmetrical about the working anode.

[0039] The two groups of second cathodes are located in the same plane in a one-to-one correspondence with the two groups of first cathodes, or the two groups of second cathodes are located outside the two groups of first cathodes.

[0040] The high-efficiency cathode electronic descaling system also includes:

[0041] a constant current unit, the constant current unit being connected to the DC power supply;

[0042] A positive and negative polarity control unit, the positive and negative polarity control unit is connected to the constant current unit and the electrode module;

[0043] AD conversion unit, the AD conversion unit is connected to the constant current unit,

[0044] An MCU control unit, the MCU control unit being connected to the AD conversion unit and the positive and negative polarity control unit respectively;

[0045] A water flow rate sensor unit, the water flow rate sensor unit being connected to the MCU control unit;

[0046] A water temperature sensor unit, connected to the MCU control unit;

[0047] A storage unit connected to the MCU control unit;

[0048] A time crystal oscillator is connected to the MCU control unit.

[0049] It is the electronic control part of the system, which mainly controls the input and output of the current of the entire system. Its main structure and functions are as follows:

[0050] (1) The system input is a DC power supply ≤36V;

[0051] (2) Constant current unit: Because the water quality (mainly the TDS of water) and water temperature in the application environment are different, the conductivity of water will change. Since the electrolysis of water to produce ozone water is affected by the current intensity, a constant current module is required to ensure the constant current output by adjusting the voltage, thereby ensuring the stability of the ozone generation efficiency during the electrolysis process. The current setting in the system is related to the area of ​​the working anode, and the basic calculation formula is:

[0052] Current intensity I (mA) = anode sheet area (cm 2 )*△(optimal unit current).

[0053] △=15~30mA / cm 2 Increasing the unit current value can improve the efficiency of electrolytic ozone generation, but will also reduce its service life.

[0054] (3) The voltage after constant current is measured by the AD conversion unit, and the voltage value is transmitted to the MCU control unit as part of the descaling control parameters.

[0055] (4) The MCU control unit records the system's operating time based on the frequency signal feedback of the time crystal oscillator, and records the operating status and corresponding time in the storage unit to solve the problem of the system being interrupted during operation and being able to continue the cathode reversal logic.

[0056] (5) The water temperature sensor collects the water temperature value during system operation and feeds it back to the MCU control unit, which can more accurately control the running time of the cathode descaling program.

[0057] (6) The water flow rate sensor unit is used by the system to obtain the parameters of the water flow conditions in the streaming application and feeds back the parameters to the MCU control unit for reference conditions for system operation.

[0058] (7) The positive and negative polarity control unit, which has a relay or electronic chip control switch inside, is used to control the positive and negative polarity and on-off operation of the DC power supply after constant current and the different electrode sheets in the electrode module. Its working logic is managed by the MCU control unit.

[0059] It is a 5-piece stacked electrode module. If the thickness of the system is allowed, it has a relatively high descaling efficiency. Its structural components are ①②③④⑤, as follows:

[0060] ① Working anode: located in the middle of the electrode module, the main material is: titanium as the base material, coated with a composite coating of metal oxides such as tin dioxide, tantalum, nickel, etc. (the existing conventional coating can be used, the same below) as a catalyst for electrolytic ozone, with a thickness of 0.5mm to 1.0mm;

[0061] ②④ are descaling cathodes: on both sides of the working anode, and the distance between the working anode and the descaling cathodes is 0.5mm, the main material can be titanium as the base material, and the surface is plated with a ruthenium, iridium metal coating or stainless steel is used as the electrode. The thickness is 0.3mm-0.5mm;

[0062] ③⑤ are working cathodes, on the outside of the descaling cathodes, and the distance between the descaling cathodes and the working cathodes is 0.5mm, the main material can be titanium as the base material, and the surface is plated with a ruthenium, iridium metal coating or stainless steel. The thickness is 0.3mm-0.5mm.

[0063] It is a 3-piece stacked electrode module, and the single-sided cathode is composed of 2 pieces of unconnected cathode pieces, and the working anode is in the middle. The structure is composed of ⑥⑦⑧⑨①0:

[0064] ⑥ working anode: in the middle of the electrode module, the main material is: titanium as the base material, and coated with a composite coating of tin dioxide, titanium, nickel, and other metal oxides as the catalyst for electrolytic ozone, and the thickness is 0.5mm-1.0mm;

[0065] ⑦⑧⑨①0 are cathodes, divided into two groups on the left and right sides of ⑥, ⑦⑨ are one side, and ⑧①0 are the other side. Each group is spaced 1mm from the working anode. The single cathode horizontal strip width is 1mm, and there is a 0.5mm gap between the upper and lower two electrodes on the same side; the requirement is that the center distance of the horizontal cathode strip is less than or equal to the distance between the cathode piece group on one side and the middle anode piece, so as to reduce the influence of the positive current of the working anode on the reverse of the cathode descaling.

[0066] The high-efficiency cathode electronic descaling method based on the above descaling system includes the following steps:

[0067] (a) According to the water flow sensor, the system is started in the state of water flow;

[0068] (b) Enter the system running state, the system enters the working mode, and the positive and negative electrodes generate ozone water through electrolytic water reaction;

[0069] (c) The MCU control unit reads whether there is an incomplete descaling program in the storage unit, and continues to start the descaling program when there is an incomplete descaling program; when there is no descaling program to start or the descaling program has been completed, it continues to run.

[0070] In step (b), whether to start the descaling program is determined according to the calculation of the water scale accumulation during the running process. In step (b), the water scale deposition speed per unit time is calculated according to the following formula:

[0071]

[0072] The MCU control unit calculates the value M scale Add the accumulated ΔM to the storage unit; scale Divide it by the set reversal threshold, and when the value is an integer, the descaling process is started.

[0073] Specific as Figure 2 As shown, the above descaling system will automatically start when a DC power supply is connected to the power input terminal. Its working process is as follows:

[0074] (1) The MCU control unit reads whether there is an unfinished descaling program in the memory. If there is an unfinished descaling program, it will continue to start the descaling program. If there is no descaling program to be started or the descaling program has been completed, it will continue to run.

[0075] (2) If it is a flow-type application mode, it is necessary to judge based on the water flow sensor and start the system only when there is water flowing.

[0076] (3) Entering the system operation state, the system enters the working mode, and the positive and negative electrodes react through water electrolysis to efficiently produce ozone water. During this operation process, the accumulation of scale on the cathode plate must be calculated. The accumulation of scale on the cathode plate depends on the voltage during electrolysis, the cumulative operating time of the system, the water temperature, and the water flow rate (i.e., in flow applications).

[0077] The relationship is as follows:

[0078] (1) Voltage: Generally speaking, the higher the voltage, the greater the current density, and the easier it is for scale to deposit. However, because this system uses a constant current mode, the lower the TDS value of the water, the higher the detected voltage. Therefore, the higher the voltage detected by the current system, the better the water quality. Therefore, the voltage is inversely proportional to the rate of scale deposition.

[0079] (2) Accumulated operating time: The scale on the cathode plate will accumulate on the surface of the cathode plate as the electrolysis water working time accumulates.

[0080] (3) The effect of water temperature on scale: The higher the water temperature → the higher the electrolysis efficiency +OH - Accelerate the generation of +Ca 2+ / Mg 2+ Intensified precipitation → faster scale deposition rate.

[0081] (4) Water flow rate: The faster the water flow, the more ions are washed away in time, the thinner the boundary layer is, and it is not easy to crystallize. Therefore, the water flow rate and the growth of scale are inversely proportional.

[0082] Based on the above four conditions plus the current density per unit anode, a formula for the scale deposition rate per unit time is generated: The meanings of the symbols are shown in Table 1.

[0083] Table 1 meanings of the symbols in the formula

[0084]

[0085]

[0086] The value of k can be obtained according to the theoretical calculation formula derived from Faraday's law and reaction kinetics:

[0087] R = k * I * C Ca2+ *M / n*F*A

[0088] In the formula, -R: scale deposition rate (unit: g / (cm 2 ·s) or mg / (cm 2 ·h));

[0089] -k: reaction efficiency coefficient (experimentally determined, usually 0.1-1.0, related to cathode material, temperature);

[0090] -I: electrolysis current (A);

[0091] -C Ca2+ : calcium ion concentration in water (mol / L);

[0092] -M: molar mass of scale (such as CaCO3 is 100 g / mol, Mg(OH)2 is 58 g / mol);

[0093] -n: ion charge number (Ca 2+ 2);

[0094] -F: Faraday constant (96485 C / mol);

[0095] -A: effective area of cathode (cm 2 ).

[0096] The operation mode of the above scale removal system is shown in Figure 3 .

[0097] (1) Connection and operation mode of electrode module:

[0098] Connection mode:

[0099] ① Working anode is connected with the connection position, which remains in the anode in any working state;

[0100] ②④ Scale removal cathodes are connected with the connection position in parallel;

[0101] ​​③⑤The working cathode is connected in parallel with the wiring position Wiring connection.

[0102] Operation mode:

[0103] (1) Working mode: The device mainly produces electrolytic ozone. The positive and negative poles of the connection points are shown in "I electrode module working mode": Connect the positive terminal, disconnect, Connect the negative terminal (such as Figure 3 shown);

[0104] (2) Descaling mode: First, descale the electrodes of the working cathode group. The positive and negative states of the connection points are as shown in "I electrode module working cathode descaling mode": Connect the positive terminal, Connect the negative terminal, Connect the positive electrode; run continuously for a period of time (normal setting, such as 3 minutes) and then change the positive and negative states of the connection points as shown in "I electrode module descaling cathode descaling mode": Connect the positive terminal, Connect the positive terminal, Connect the negative electrode; run continuously for a period of time (normal setting, such as 2 minutes), and then switch back to normal working mode.

[0105] (2) Description of the connection and operation mode of the electrode module:

[0106] Connection method:

[0107] ⑥ Working anode and wiring position connection, which remains anode in any working state;

[0108] ⑦⑧The cathode is connected in parallel with the wiring position connect;

[0109] ⑨①0 cathode is connected in parallel with the wiring position connect.

[0110] Operation mode:

[0111] (1) Working mode: The equipment mainly produces electrolytic ozone. The positive and negative poles of the connection points are shown in "II Electrode Module Working Mode": Connect the positive terminal, Connect the negative terminal, Connect the negative terminal;

[0112] (2) Descaling mode: The electrode polarity is connected as shown in "Ⅱ electrode module descaling mode 1". Connect the positive terminal, Connect the positive terminal, Connect the negative pole. The electrodes ⑦⑧ are in the descaling state. After a period of time, the electrode polarity is changed, as shown in "Ⅱ electrode module descaling mode 2". Connect the positive terminal, Connect the negative terminal, Connect the positive terminal. The electrode ⑨①0 is in the descaling state for a period of time and then switches to the working mode.

[0113] Improve the following technical issues of electronic descaling in the hydrolysis ozone process:

[0114] 1) For the anode coating (such as tin dioxide), when it is reversed to the cathode in a reducing environment, the coating dissolves and falls off;

[0115] 2) Certain cathode materials (such as stainless steel) are oxidized during long-term reverse descaling, causing corrosion;

[0116] 3) Using timed reversal descaling is affected by the uncertainty of the equipment's working time. If the equipment is started at intervals, the reversal time will be insufficient, resulting in poor descaling effect.

[0117] 4) The water quality (TDS) and water temperature in different regions are different, and the conditions for reverse descaling are also different. It is necessary to match the reversal time of different water quality to more effectively improve the efficiency of ozone generation and the effect of descaling.

[0118] The above embodiments are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made in accordance with the spirit of the present invention are intended to be covered by the scope of protection of the present invention.

Claims

1. A high-efficiency cathode electronic descaling system, characterized in that: It includes: An electrode module, the electrode module comprising a working anode, a first cathode disposed on both sides of the working anode, and a second cathode disposed on both sides of the working anode; A DC power supply having a positive electrode and a negative electrode; the working anode is connected to the positive electrode, two groups of the first cathodes are connected in parallel and then alternatively connected to the positive electrode or the negative electrode, and two groups of the second cathodes are connected in parallel and then alternatively connected to the positive electrode or the negative electrode; the first cathode and the second cathode are not connected to the positive electrode at the same time.

2. The high-efficiency cathode electronic descaling system according to claim 1, characterized in that: The two groups of the first cathodes are symmetrical with respect to the working anode, and the two groups of the second cathodes are symmetrical with respect to the working anode.

3. The high-efficiency cathode electronic descaling system according to claim 2, characterized in that: The two groups of the second cathodes and the two groups of the first cathodes are located in the same plane in a one-to-one correspondence, or the two groups of the second cathodes are located outside the two groups of the first cathodes.

4. The high-efficiency cathode electronic descaling system according to claim 1, characterized in that: It also includes: a constant current unit, the constant current unit being connected to the DC power supply; A positive and negative polarity control unit, the positive and negative polarity control unit is connected to the constant current unit and the electrode module; AD conversion unit, the AD conversion unit is connected to the constant current unit, An MCU control unit, the MCU control unit being connected to the AD conversion unit and the positive and negative polarity control unit respectively; A water flow rate sensor unit, the water flow rate sensor unit being connected to the MCU control unit; A water temperature sensor unit, connected to the MCU control unit; A storage unit connected to the MCU control unit; A time crystal oscillator is connected to the MCU control unit.

5. A high-efficiency cathode electronic descaling method, characterized in that: The following steps are involved: (a) Based on the water flow rate sensor, the system is activated when water is flowing; (b) Entering the system operation state, the system enters the working mode, and the positive and negative electrodes produce ozone water through water electrolysis reaction; (c) The MCU control unit reads whether there is an unfinished descaling program in the storage unit. If there is an unfinished descaling program, the descaling program will continue to be started; if there is no descaling program that needs to be started or the descaling program has been completed, the descaling program will continue to run.

6. The high-efficiency cathode electronic descaling method according to claim 5, characterized in that: In step (b), whether to start the descaling program is determined based on the calculated scale accumulation on the cathode plates during operation.

7. The high-efficiency cathode electronic descaling method according to claim 6, characterized in that: In step (b), the scale deposition rate per unit time is calculated according to the following formula: The MCU control unit calculates the value M scale Add the accumulated ΔM to the storage unit; scale Divide it by the set reversal threshold, and when the value is an integer, the descaling process is started.

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