A potential compensation device for protecting a low-temperature multi-effect seawater desalination device

Abstract

This application provides a potential compensation device for protecting a low-temperature multi-effect seawater desalination unit, comprising an electrochemical ion exchange reactor, a power supply system, a monitoring system, and an intelligent control system. The electrochemical ion exchange reactor includes an anode, a cathode, and a reaction chamber. The anode is an aluminum alloy electrode that undergoes an oxidation reaction under the action of current, losing electrons and dissolving to produce aluminum ions. The cathode is an electrode with a stainless steel substrate and a Ni-Co-P catalyst layer. Under the action of an applied current, iron ions in seawater undergo a reduction reaction on the cathode surface to generate elemental iron, while manganese ions are oxidized by dissolved oxygen under the locally weakly alkaline conditions of the cathode, transforming into oxide precipitates. The weakly alkaline conditions refer to a pH of 8-9, where precipitation is achieved through the flocculation of aluminum ion hydrolysis products. The reaction chamber accommodates the anode and cathode, forming a closed reaction space. This application employs an external current ion exchange protection technology with aluminum electrodes to prevent corrosion of the aluminum alloy heat exchange tube bundle of the low-temperature multi-effect seawater desalination unit by iron and manganese ions in seawater, ensuring the stable operation of the seawater desalination unit and the quality of the desalinated water.

Description

Technical Field

[0001] This application relates to the field of seawater desalination technology, specifically to a potential compensation device and method for protecting a low-temperature multi-effect seawater desalination device. Background Technology

[0002] Low-temperature multi-effect seawater desalination technology, with its advantage of low operating temperature, can fully utilize the 50-70℃ low-temperature waste heat generated by power plants and chemical plants. This process typically employs multiple multi-effect evaporators connected in series to achieve staged utilization of steam heat. However, in traditional series structures, the structures and functions of each multi-effect evaporator are basically the same, without functional differentiation design. During operation, motive steam flows within the heat exchange tube bundle, and the feed seawater is sprayed onto the outer wall of the heat exchange tube bundle through the spray tube bundle. Some of the seawater absorbs the latent heat of the steam and vaporizes to form secondary steam, which enters the next effect, thus achieving a multi-stage evaporation and condensation process, producing desalinated water several times the amount of steam.

[0003] Currently, to delay the corrosion of aluminum alloy (such as 5052) heat exchange tube bundles in low-temperature multi-effect seawater desalination devices, ion exchangers using aluminum rings (5052) as the ion exchange medium are often installed during the seawater pretreatment stage. The principle is to utilize the replacement reaction between the aluminum rings and iron and manganese ions in the seawater to remove these corrosive ions. However, this method has significant drawbacks. For example, after long-term operation of the seawater pretreatment system, sludge from the seawater adheres to the surface and inner wall of the aluminum rings, hindering the ion exchange reaction and causing the ion exchanger to fail. This, in turn, allows corrosive ions to react with the heat exchange tube bundle, causing corrosion and perforation, thus affecting the quality of the desalinated water.

[0004] In view of this, the present invention is hereby proposed. Summary of the Invention

[0005] This application provides a potential compensation device and method for protecting a low-temperature multi-effect seawater desalination device. The purpose is to selectively remove iron and manganese ions from seawater, effectively prevent corrosion of the aluminum alloy heat exchange tube bundle of the low-temperature multi-effect seawater desalination device, eliminate the influence of slime adhesion on the ion exchange process, ensure the long-term stable operation of the ion exchange system, reduce maintenance costs, improve the operating efficiency of the seawater desalination device and the quality of the desalinated water, and enable the desalinated water to meet the standards for recycling.

[0006] This invention can independently adjust the potential range and functional positioning of each replacement chamber based on variables such as changes in influent water quality and the corrosion status of electrode components, achieving continuous and stable operation. The power system is equipped with a multi-channel independent control module, with one control channel corresponding to each replacement chamber, allowing independent switching of continuous power control modes to meet the potential requirements of different replacement chambers. The water quality monitor can be equipped with detection points at the inlet and outlet of each replacement chamber to collect Fe data. 3+ Fe 2+ Mn2+ Concentration signal, real-time acquisition of average potential value to avoid single-point detection error.

[0007] The present invention employs a series connection mode between the replacement chambers. The reaction chamber comprises several replacement chambers (n≥3). In this embodiment, three core reaction units are preferably set up: a first replacement chamber, a second replacement chamber, and a third replacement chamber. Each replacement chamber is connected in series and interconnected through corrosion-resistant pipes and electric regulating valves, forming a continuous reaction flow channel where "seawater flows through sequentially and ions are transformed step by step." Each replacement chamber is independently equipped with a power control module, a potential monitoring module, and an ion concentration detection module, which can achieve independent and precise control of the potential. A filter chamber is connected in series at the end to ensure timely interception of reaction products and avoid cross-chamber interference.

[0008] The above can be understood as potential gradient design. In a multi-step electrochemical process, the working potential is divided into several intervals based on the thermodynamic potential and kinetic requirements of each reaction. Corresponding potentials are applied in different reaction regions (or time periods). Figure 6 ).

[0009] In this invention, pretreated seawater sequentially enters the first, second, and third replacement chambers. The intelligent control system sets a specific potential range for each replacement chamber based on the standard electrode potential differences of each ion's redox reaction, thereby achieving Fe... 3+ to Fe 2+ Then, the stepwise targeted reduction of elemental iron is carried out, while simultaneously completing the reduction of Mn. 2+ The process involves a staged reaction of oxidation to MnO2 followed by flocculation and co-precipitation removal. The above reaction is controlled by potential, with iron and manganese metals in different ionic states undergoing concentrated electrochemical reactions sequentially in the first, second, and third displacement chambers. This sequential arrangement can be understood as a method; it should be noted that this arrangement only focuses on metal ions in different valence states, rather than absolutely excluding possible side reactions from other trace metal ions.

[0010] It should be noted that all electrode potential values ​​involved in this invention are measured and defined relative to a standard hydrogen electrode. Unless otherwise explicitly stated, the embodiments and numerical ranges described below are all based on this potential reference.

[0011] The specific control logic is as follows:

[0012] First displacement chamber: The anode maintains an open-circuit potential of -1.55V to -1.60V, and electrons are supplied only through the galvanic cell reaction to satisfy Fe 3+ →Fe 2+ Low electronic demand; Second displacement chamber: The anode working potential is adjusted to -1.50V to -1.58V, and an external power supply is used to assist in the electron supply, ensuring Fe... 2+ →Electron requirements of elemental Fe; The third replacement chamber: The anolyte operating potential is adjusted to -1.15V to -1.30V, weakening the anolyte electron supply intensity. At this time, the cathode still maintains sufficient polarization, generating a locally weakly alkaline environment and promoting dissolved oxygen reduction. The weakly alkaline condition refers to a pH of 8 to 9, achieving Mn... 2+ →MnO2 precipitation, Al generated at the anode 3+ Hydrolysis produces flocculation, which synergistically removes suspended particles.

[0013] Setting the anode working potential range and controlling the cathode potential of the three replacement chambers:

[0014] I. Core Potential Control Logic Relationship

[0015] The core reaction in the anode (5052 aluminum alloy) is Al-3e. - →Al 3+ The standard oxidation potential is -1.66V. Its operating potential must meet two core conditions: ① It must be sufficiently negative to stably release electrons, ensuring an electron supply for the cathode reduction reaction; ② It must form a reasonable potential difference with the target cathode potential to avoid excessive occurrence of side reactions such as hydrogen evolution. Combining the standard electrode potentials of the cathode reactions in each replacement chamber, the operating potential range of the anode is determined through a logic chain of "cathode potential requirement → electron supply intensity → anode potential matching".

[0016] II. Working potential settings for each replacement chamber

[0017] 1. First replacement chamber (Fe) 3+ →Fe 2+ )

[0018] Anode operating potential range: -1.55V to -1.60V;

[0019] Cathode target potential: slightly negative than Fe 3+ / Fe 2+ The standard reduction potential is +0.77V, but the actual control is +0.64V to +0.76V to ensure Fe 3+ Prioritize restoration;

[0020] Potential difference range 2.24V~2.31V, Fe 3+ / Fe 2+ The standard reduction potential is much positive than that of Fe. 2+ Due to the strong potential difference of 2.24V to 2.31V, electrons are preferentially supplied to Fe. 3+ Restoration will not trigger Fe prematurely. 2+ or Mn 2+The reduction reaction achieves targeted and preferential reduction.

[0021] 2. Second replacement chamber (Fe) 2+ →Fe element)

[0022] Anode operating potential range: -1.50V to -1.58V; Cathode target potential: must be negative than Fe 2+ The standard reduction potential of Fe is -0.44V, but it is actually controlled to be between -0.51V and -0.61V. The potential difference range is 0.97V to 0.99V. A moderate potential difference is sufficient to allow divalent iron ions to become elemental iron, and it can also avoid excessive consumption of the anode due to excessive electron supply, which is beneficial to extending the service life of the anode.

[0023] 3. Third replacement chamber (Mn) 2+ →MnO2)

[0024] Anode operating potential range: -1.15V to -1.30V; Cathode target potential: +0.435V~+0.565V weak electric field environment, only plays a role in regulating the directional migration of ions, does not reduce MnO2:

[0025] Step 1: Mn 2+ Oxidized to MnO2

[0026] The third replacement chamber's water inlet channel can be circulated with air or oxygen to provide O2; the 2% Ru doping in the Ni-Co-P catalyst layer, with Ru being present at a 2% doping content, can efficiently catalyze dissolved oxygen activation, generating highly reactive superoxide radicals (O2). - O2 - It is a strong oxidizing agent, and under locally weakly alkaline conditions, it will oxidize Mn. 2+ Rapid oxidation to MnO2, wherein the weakly alkaline conditions refer to a pH of 8–9;

[0027] Reaction formula: ;

[0028] Step 2: Al 3+ Hydrolysis forms flocs

[0029] Reaction formula: ;

[0030] Al(OH)3 electrostatically adsorbs and traps ultrafine MnO2 to form a composite coprecipitate, which is easy to filter and has strong stability.

[0031] With a potential difference range of 1.715V to 1.735V, this mild electric field can enhance the directional migration of ions and synergistically promote Mn production in the catalytic layer. 2+Efficient oxidation to generate MnO2; simultaneously regulating the stable dissolution of Al from the aluminum alloy anode. 3+ This ensures stable floc formation and facilitates the flocculation and sedimentation of manganese dioxide particles. A moderate potential difference avoids both the reverse reduction of MnO2 and the hydrogen evolution side reactions, while also ensuring stable reaction kinetics and maintaining continuous and efficient removal of manganese components.

[0032] Potential difference calculation follows a two-way calculation of "cathode potential upper limit - anode potential upper limit" and "cathode potential lower limit - anode potential lower limit" to ensure coverage of the entire operating range.

[0033] III. The anode and cathode can be independently and precisely controlled.

[0034] 1. Each replacement chamber is independently equipped with a power control module, a potential monitoring module, and an ion concentration detection module. Potential thresholds can be set for the anode and cathode of a single replacement chamber, achieving "one control per chamber and separate adjustment for each electrode". This avoids potential interference across chambers and electrodes, which is a manifestation of the potential gradient design in different replacement chambers.

[0035] 2. The core of cathode potential control is matching the standard reduction potential of ions and precisely setting the target range through power supply regulation to ensure the efficient reduction reaction of iron ions. Simultaneously, the hydrogen evolution reaction and oxygen reduction reaction occurring at the cathode create a localized weakly alkaline region on the electrode surface, promoting the reduction of Mn by dissolved oxygen. 2+ Chemical oxidation produces MnO2 precipitate, and the weakly alkaline conditions refer to a pH of 8-9. The core of the potential control for the anode (5052 aluminum alloy) is "maintaining a stable electron release capability." As long as it is controlled within its own stable operating range, the potential can be finely adjusted to match the electron demand of the cathode. The control logics of the two are independent and do not affect each other.

[0036] 3. The power supply system can switch between low current constant potential, continuous DC, and pulsed DC modes, and has multi-channel independent control capability to drive multiple reaction chambers respectively. The monitoring system monitors the cathode potential and adjusts the power output accordingly to achieve closed-loop control of the cathode potential.

[0037] The aim is to eliminate specific harmful substances such as iron and manganese in seawater by consuming the anodes of each replacement chamber, thereby protecting the aluminum alloy heat exchange tube bundle at the downstream end.

[0038] As the anode aluminum is consumed, it undergoes severe self-corrosion and dissolution in seawater, generating positively charged aluminum hydroxide colloid. The specific electrochemical reaction is as follows:

[0039] 1. Active dissolution of aluminum metal;

[0040] 2. Oxygen and water dissolved in seawater accept electrons to form hydroxide ions;

[0041] 3. Aluminum ions combine with hydroxide ions, undergoing hydrolysis and polymerization to form a series of aluminum hydroxide complexes ranging from monomers to polymers, ultimately generating amorphous aluminum hydroxide gel. This aluminum hydroxide has a huge specific surface area and abundant surface hydroxyl groups, and is positively charged in water.

[0042] 4. During the flocculation process, iron and manganese colloids / particulate matter in seawater are negatively charged, neutralizing the charge. Positively charged aluminum hydroxide colloids bind to these iron and manganese colloids / particulate matter through electrostatic interactions, disrupting the colloid's stability. Adsorption bridging: The long-chain polymer structure of aluminum hydroxide can "bridge" between particles, connecting multiple particles to form micro-flocs. Netting and sweeping: During sedimentation, the large flocs act like a large net, enveloping fine particles along the way and causing them to settle together.

[0043] Aluminum metal as an anode releases Al 3+ By adjusting the potential to a controllable and continuous state, a long-term, localized flocculation field is formed, which is superior to the effect of adding large amounts of flocculant for removing iron and manganese ions in the replacement chamber.

[0044] To achieve the above objectives, the present invention employs the following technical solution:

[0045] A potential compensation device for protecting a low-temperature multi-effect seawater desalination device includes an electrochemical ion exchange reactor, a power supply system, a monitoring system, and an intelligent control system. The electrochemical ion exchange reactor includes an anode, a cathode, and a reaction chamber.

[0046] The anode is an aluminum alloy electrode, which undergoes an oxidation reaction under the action of current, loses electrons and dissolves to produce aluminum ions;

[0047] The cathode is a composite electrode with a stainless steel substrate and a Ni-Co-P catalyst layer supported. Under an applied electric field, the cathode potential is negative to the standard reduction potential of iron ions, driving Fe... 3+ / Fe 2+ A directional reduction reaction occurs on the cathode surface, generating elemental iron to remove it. The hydrogen evolution reaction and oxygen reduction reaction at the cathode create a locally weakly alkaline environment on the electrode surface. This weakly alkaline condition refers to a pH of 8-9, which promotes the removal of Mn by dissolved oxygen. 2+ Chemical oxidation to MnO2 precipitate achieves manganese removal. The Ni-Co-P catalyst layer enhances the oxygen reduction reaction activity and strengthens the formation of local weak alkalinity. The Ni-Co-P alloy combines excellent catalytic activity with a high hydrogen evolution overpotential, effectively matching Fe... 3+ / Fe 2+ The reduction potential requirement is met to ensure iron deposition efficiency while suppressing excessive hydrogen evolution side reactions and improving the selectivity of metal reduction reactions.

[0048] The reaction chamber contains the anode and cathode, forming a closed reaction space.

[0049] In one specific implementation, the power supply system is an adjustable DC power supply with an output voltage range of 0–10V and an output current range of 0–20A.

[0050] The power regulation module of the power system precisely regulates the output voltage and current of the DC power supply according to the instructions of the intelligent control system.

[0051] The power system employs pulse width modulation technology to achieve rapid response and precise control of the power output, ensuring stable operation of the reactor under different operating conditions.

[0052] In one specific implementation scheme, the monitoring system includes a water quality monitor, a potential monitor, and a flow monitor;

[0053] The water quality monitoring instrument is a spectrophotometer or ion chromatograph, which monitors the concentration of iron ions, manganese ions and aluminum ions in seawater in real time and provides timely feedback on changes in water quality.

[0054] The potential monitor monitors the potential changes of the anode and cathode to determine the reaction state of the electrodes and the operational stability of the system.

[0055] The flow monitoring instrument is an electromagnetic flow meter or an ultrasonic flow meter, which monitors the flow rate of seawater in real time.

[0056] In one specific implementation scheme, the intelligent control system includes a controller, a sensor module, and a data analysis module;

[0057] The controller is a programmable logic controller that adjusts the output parameters of the power system in real time based on the data collected by the monitoring system.

[0058] The sensor module includes a water quality sensor, a potential sensor, and a flow sensor, which are responsible for collecting data on ion concentration, electrode potential, and seawater flow rate in seawater and transmitting them to the controller.

[0059] The data analysis module analyzes and processes the data collected by the sensor to establish ion concentration change models and reaction efficiency models.

[0060] In one specific implementation, the reaction chamber includes a first replacement chamber, a second replacement chamber, a third replacement chamber, and a filtration chamber. The anode is in the shape of a spiral corrugated plate structure and is uniformly arranged in the circumferential direction in the first replacement chamber, the second replacement chamber, and the third replacement chamber to form a "ring array".

[0061] The cathode is a spiral corrugated plate and is arranged parallel to the anode.

[0062] The anode and cathode adopt a coaxial spiral nested structure, with the outer spiral anode and the inner spiral cathode coaxially arranged in the first, second, and third cylindrical replacement chambers. Through the matching design of spiral parameters, such as pitch, diameter, and direction of rotation, the seawater forms a continuous disturbance in the spiral flow channel, and at the same time, the potential difference between the anode and cathode spontaneously forms a galvanic cell circuit.

[0063] The reaction chamber is made of corrosion-resistant plastic material. Seawater flows into the reaction chamber from one end. Under the action of an electric field, the cations in the seawater migrate to the cathode and react. The treated seawater flows out from the other end.

[0064] In one specific implementation, the power supply system is a pulsed power supply.

[0065] In one specific implementation scheme, the first replacement chamber, the second replacement chamber, and the third replacement chamber are connected in series and adopt a nested structure, with a potential gradient design for different replacement chambers.

[0066] In one specific implementation, the electrochemical ion exchange reactor is a built-in structure installed inside a seawater pipeline.

[0067] The invention also provides a method for compensating a potential compensation device for protecting a low-temperature multi-effect seawater desalination device. The potential compensation device for protecting a low-temperature multi-effect seawater desalination device, as described above, includes the following steps:

[0068] Seawater pretreatment: Seawater is filtered and settled to remove large particulate impurities and suspended solids.

[0069] Electrochemical ion exchange reaction: Pretreated seawater enters the reaction chamber of the electrochemical ion exchange reactor;

[0070] Real-time monitoring and control: The monitoring system monitors the ion concentration, electrode potential and seawater flow rate in seawater in real time and transmits the data to the intelligent control system. The intelligent control system adjusts the output parameters of the power system in real time based on the data.

[0071] The surface area of ​​the "ring array" of electrodes in the replacement chamber is designed to be adjustable based on the flow rate and ion concentration of the seawater being treated. This is achieved by combining the flow rate (Q) and ion concentration (C) of the seawater with the formula j=I / A. j=I / A is the defining formula for current density in an electrochemical system and a core formula for understanding electrode reaction efficiency and surface area adjustment design. It represents the quantitative relationship between total current (I), electrode surface area (A), and reaction intensity per unit area (j). The relationship between the ring array surface area and j is explained: an increase in Q leads to a shorter residence time, and an increase in C leads to an increased reaction load per unit volume. Both result in the need to process more ions, thus requiring a larger A to distribute the current. However, j should not be too high (side reactions) or too low (incomplete reaction). The adjustment of A aims to maintain the stability of j through j=I / A when Q and C change, or to adjust A in constant current / constant voltage mode to adapt to load changes. In practice, the above formula and requirements can be applied in the proof-of-concept design of products; this is not the focus of this invention.

[0072] Seawater discharge after treatment: Seawater that has undergone electrochemical ion exchange treatment flows out of the reaction chamber and enters the subsequent seawater desalination process.

[0073] Compared with the prior art, this application has at least the following advantages:

[0074] 1. Highly efficient removal of corrosive ions: This generation of compensation device can efficiently remove iron and manganese ions from seawater, with iron and manganese ion removal rates exceeding 80%. This effectively avoids corrosion of the aluminum alloy heat exchange tube bundle in the low-temperature multi-effect seawater desalination device and extends the service life of the tube bundle.

[0075] 2. Unaffected by slime: The externally driven ion exchange method avoids the impact of slime adhesion on the ion exchange process, ensuring long-term stable operation of the system. Compared with traditional aluminum ring ion exchangers, the maintenance cycle is significantly extended, and maintenance costs are significantly reduced.

[0076] 3. Potential gradient design and energy saving: After removing iron and manganese ions, the intelligent control system can adjust the output parameters of the power system in real time according to the changes in seawater quality, realizing intelligent operation and energy saving of the system.

[0077] 4. Easy to install and maintain: The system adopts a modular design, with each component operating independently yet collaboratively, facilitating system installation, maintenance, and upgrades. When retrofitting existing seawater desalination plants, the construction period is short, and the impact on production is minimal. Attached Figure Description

[0078] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0079] Figure 1 This is a schematic diagram of the potential compensation device for protecting a low-temperature multi-effect seawater desalination device provided by the present invention;

[0080] Figure 2 This is a schematic diagram of the first replacement chamber provided by the present invention;

[0081] Figure 3 This is a schematic diagram of the coaxial spiral nested structure component provided by the present invention;

[0082] Figure 4 A schematic diagram of the filter chamber provided by this invention;

[0083] Figure 5 This is a schematic diagram of an embodiment of the nested structure of the first replacement chamber, the second replacement chamber, and the third replacement chamber provided by the present invention;

[0084] Figure 6 This is a schematic diagram of the potential gradient design of the present invention.

[0085] in:

[0086] 1-Electrochemical ion exchange reactor; 2-Power supply system; 3-Monitoring system; 4-Intelligent control system; 5-Reaction chamber; 6-First replacement chamber; 7-Second replacement chamber; 8-Third replacement chamber; 9-Anode; 10-Cathode; 11-Anode storage chamber; 12-Collector box; 13-Telescopic controller; 14-Fixed shaft; 15-Limit locking pin; 16-Filter chamber. Detailed Implementation

[0087] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0088] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0089] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "connected," and "connected" should be interpreted broadly. For example, they can refer to fixed connection, detachable connection, or integral connection; they can refer to mechanical connection or electrical connection; they can refer to direct connection or indirect connection through an intermediate medium; and they can refer to the connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0090] To more clearly illustrate the technical solutions in this invention, specific embodiments are described below.

[0091] Example 1

[0092] This embodiment provides a potential compensation device and method for protecting a low-temperature multi-effect seawater desalination device. It is mainly to solve the problems in the prior art such as seawater corrosion of aluminum alloy heat exchange tube bundles, the influence of sludge adhesion on the ion exchange process, high maintenance cost of ion exchange system, low operating efficiency of seawater desalination device and failure of desalinated water quality to meet recycling standards.

[0093] In this embodiment, as Figure 1 As shown, the compensation device is applied to a low-temperature multi-effect seawater desalination device, including an electrochemical ion exchange reactor 1, a power supply system 2, a monitoring system 3, and an intelligent control system 4.

[0094] In this embodiment, the electrochemical ion exchange reactor 1 includes an anode 9, a cathode 10, and a reaction chamber 5;

[0095] Among them, anode 9 is made of aluminum alloy (such as 5052) as the main material. Its main function is to make aluminum undergo an oxidation reaction under the action of electric current, lose electrons and dissolve to produce Al. 3+ (Aluminum ions);

[0096] Anode 9 reaction (anode 9 surface): The aluminum alloy spontaneously oxidizes and dissolves, losing electrons, that is:

[0097] (Electrode reaction formula 1);

[0098] The spiral structure increases the specific surface area, allowing aluminum ions to diffuse rapidly into seawater (the diffusion rate is 2.5 times that of traditional aluminum rings).

[0099] The cathode employs a composite structure with a stainless steel substrate and a Ni-Co-P catalyst layer, which can effectively receive electrons released from the anode 9, driving differentiated redox transformation of iron and manganese ions in seawater in the near-interface region of the cathode. 2+ Instead of direct electro-oxidation on the cathode electrode surface, the active oxide species generated by activating dissolved oxygen through the Ni-Co-P catalytic layer are indirectly oxidized around the cathode interface to generate manganese dioxide. Iron ions, on the other hand, directly gain electrons on the cathode surface and undergo electro-reduction, transforming into elemental iron in a directional manner. This achieves the stepwise conversion and separation of iron and manganese ions in seawater.

[0100] 1. Anode process:

[0101] Anode 9 is made of aluminum alloy (such as 5052). Under the action of an applied current, aluminum undergoes oxidation and dissolution. The dominant reaction is that aluminum atoms lose 3 electrons to generate aluminum ions. The dissolved product rapidly hydrolyzes in the weakly alkaline environment of seawater. The weakly alkaline condition refers to a pH of 8-9, generating aluminum hydroxide colloid with flocculation effect.

[0102] 2. Cathode process:

[0103] The standard electrode potential for ferric ions in seawater to gain electrons and generate ferrous ions in seawater is +0.77V, both of which are reduction potentials relative to the standard hydrogen electrode.

[0104] The standard electrode potential for ferrous ions in seawater to gain electrons and form solid iron is -0.44V, which is the reduction potential relative to the standard hydrogen electrode.

[0105] divalent manganese ions (Mn) in seawater 2+ Under weakly alkaline conditions, it is oxidized, losing electrons to form manganese dioxide (MnO2) precipitate. These conditions refer to a pH of 8–9. 2+ The equilibrium potential of the MnO2 redox couple is approximately +0.3V, which is significantly higher than the cathode potential set by this system. Therefore, MnO2 will not be reduced by the cathode and can exist stably.

[0106] It should be noted that in actual seawater, the reduction potential is in a relatively positive range. Therefore, applying a suitable negative potential to the cathode 10 can drive the reactions in the first replacement chamber 6 and the second replacement chamber 7 to proceed smoothly. To avoid the reverse reduction of manganese dioxide in the third chamber 8, and to ensure that the potential of the third chamber is maintained at +0.435V to +0.565V, the cathode potentials of the first replacement chamber 6 and the second replacement chamber 7 are optimized to -0.4V to -0.6V.

[0107] The ferric ion gains an electron and is reduced to the ferrous ion, that is:

[0108] (Electrode reaction formula 2);

[0109] The ferrous ion gains two more electrons and is reduced to metallic iron, i.e.:

[0110] (Electrode reaction formula 3);

[0111] The primary function of the stainless steel electrode with a Ni-Co-P catalytic layer, cathode 10, is to efficiently catalyze redox reactions to ensure a smooth current circuit and stable cathode potential. Its key function is the catalytic reduction of ferric ions (Fe3+) in colloidal form in seawater. 3+ The colloid promotes the conversion of soluble ferrous ions (Fe2+) into soluble ferrous ions. 2+ The transformation of ferric ions into ferrous ions is mainly accomplished in the first substitution chamber 6, where ferric ions gain electrons to form ferrous ions. This step disrupts the stable state of iron, creating conditions for its subsequent precipitation. The formation of elemental iron from ferrous ions is mainly accomplished in the second substitution chamber 7.

[0112] In this embodiment, as Figure 1 As shown, the reaction chamber 5 includes, from top to bottom, a first displacement chamber 6, a second displacement chamber 7, a third displacement chamber 8, and a filter chamber 16. It is made of corrosion-resistant plastic material and contains an anode 9 and a cathode 10, forming a closed reaction space. Seawater flows in from one end of the reaction chamber 5. Under the action of an electric field, the cations in the seawater migrate to the cathode 10 and react. The treated seawater flows out from the other end.

[0113] like Figure 3As shown, the anode 9 is shaped like a spiral corrugated plate, replacing the traditional aluminum ring. The cathode 10 and anode 9 form a coaxial spiral nested structure assembly, which, from top to bottom, also includes a current collector 12, a telescopic controller 13, an anode storage chamber 11, and a fixed shaft 14. A limiting pin 15 is provided on the bottom of the fixed shaft 14. The fixed shaft 14 and the cathode 10 are coaxially positioned and assembled, providing axial support and positioning reference for the cathode 10. The coaxial arrangement of the two ensures the precise alignment of the coaxial spiral nested structure of the cathode 10 and the anode 9. The limiting pin 15 and other structures of the fixed shaft 14 work together with the cathode 10 to maintain the stability of the cathode 10 position during the replacement of the anode 9, avoiding displacement due to the removal or installation of the anode 9, and ensuring the precise connection of the spiral structure of the anode 9 and the cathode 10 and the uniformity of current distribution.

[0114] like Figure 3 As shown, the anode 9 has a spiral corrugated plate structure, which, together with the mirror-fitted cathode 10, forms a coaxial spiral nested structure assembly. This assembly integrates, from top to bottom, a current collector 12, a telescopic controller 13, an anode storage chamber 11, and a fixed shaft 14. The fixed shaft 14 has a limiting locking pin 15 at its bottom. The precise nesting of the spiral structures of the anode 9 and cathode 10 utilizes their potential difference to spontaneously form a galvanic cell circuit. Simultaneously, the spiral flow channel enhances seawater disturbance to improve ion mass transfer efficiency, overcoming the inefficient mass transfer problem of traditional distributed electrodes. The current collector 12 achieves parallel conduction of each anode 9 through a snap-fit ​​connection with the quick-plug terminal at the top of the anode 9, avoiding current fluctuations caused by series conduction and ensuring uniform current distribution to support the staged potential control of each replacement chamber. The telescopic controller 13 initiates a linkage action under the command of the intelligent control system 4. Its drive component can axially push the anode storage chamber 11 along the fixed shaft 14. The anode storage chamber 11 contains stacked spare ions. The anode 9 is temporarily fixed by an elastic positioning buckle on the side wall of the replacement chamber. This buckle automatically retracts and unlocks under driving pressure, precisely releasing a single spare anode 9 to the assembly path, which is different from the cumbersome operation of traditional manual single-filling. At the same time, the fixed shaft 14 forms a coaxial positioning constraint with the adaptation structure of the central hole of the cathode 10, providing stable axial support for the cathode 10 and avoiding radial displacement that is easy to occur with traditional simple support. When the old anode 9 is removed, the elastic claw of the limit locking pin 15 automatically pops up and engages with the limit groove at the bottom of the cathode 10. After the spare anode 9 is pushed by the telescopic controller 13 and guided along the fixed shaft 14 to the preset position and completes the snap-fit ​​conductive connection with the current collector box 12, the limit locking pin 15 retracts and resets under the command of the intelligent control system 4. The entire process is coordinated by the functions of driving release, positioning support, and limit locking, thereby ensuring the precise connection between the anode 9 and the cathode 10 and avoiding problems such as uneven electric field distribution or reduced reaction efficiency caused by displacement.

[0115] like Figure 2As shown, within the first replacement chamber 6, coaxial spiral nested structure components are evenly arranged along the circumferential direction. Multiple coaxial spiral nested structure components form a "ring array," i.e., a coaxial spiral nested structure module. This module is constructed via a central shaft, upper and lower partitions, gears, and mechanical limiting sliders. After rotation, the gears and limiting blocks engage and lock the module. Specifically, partitions are provided, each with circular through holes evenly distributed circumferentially. The coaxial spiral nested structure components are fixed to the partitions through these through holes, forming a coaxial spiral nested structure module with the partitions.

[0116] The surface area of ​​anode 9 is designed to expand and contract according to the flow rate and ion concentration of the seawater being treated; the first replacement chamber 6 has a central shaft with the center of the upper and lower partitions as the support point. The central shaft is fixedly connected to the upper and lower ends of the first replacement chamber 6. The partitions are set on the central shaft through bearings, and the center point of the partitions coincides with the center line of the central shaft. With this configuration, the coaxial spiral nested structure module can rotate along the central shaft. When it is necessary to replace the coaxial spiral nested structure component, the coaxial spiral nested structure module is rotated to replace the coaxial spiral nested structure component.

[0117] To ensure the rotation effect of the coaxial spiral nested structure module, in this embodiment, the coaxial spiral nested structure module is connected to the side wall of the first replacement chamber 6 via a bearing. Furthermore, to prevent the coaxial spiral nested structure module from rotating during operation, a mechanical limit slider is also provided to limit its movement. The coaxial spiral nested structure module can be rotated manually or controlled by the intelligent control system 4.

[0118] The mechanical limiting slider can be set on the central shaft or on the side wall of the first replacement chamber 6. The mechanical limiting slider is a meshing limiting block that meshes with a gear. When the mechanical limiting slider is set on the central shaft, the limiting block is set on the central shaft and the gear is set on the partition. When the mechanical limiting slider is set on the side wall of the first replacement chamber 6, the limiting block is set on the side wall of the first replacement chamber 6 and the gear is set on the partition. The limiting block can be controlled manually or by the intelligent control system 4.

[0119] In this embodiment, the first replacement chamber 6, the second replacement chamber 7, and the third replacement chamber 8 are arranged in series with pipelines and circuits, and the loop current is equal everywhere under the series operation condition; each chamber is an independent reaction system, and the anode potential, cathode potential, and chamber potential difference of each chamber are independent of each other, and the redox reaction potential window of each chamber can be adjusted separately to achieve stepwise selective redox and replacement of different metal ions.

[0120] To ensure good electric field distribution and ion exchange effect, such as Figure 3As shown, the cathode 10 and anode 9 are arranged in parallel. The cathode 10 and anode 9 adopt a coaxial spiral nested structure. The outer spiral anode 9 and the inner spiral cathode 10 are coaxially arranged in the cylindrical first displacement chamber 6, the cylindrical second displacement chamber 7 and the cylindrical third displacement chamber 8. By utilizing the "flow channel extension and turbulence enhancement" characteristics of the spiral structure, the problems of low mass transfer efficiency and insufficient reaction contact of traditional flat plate or columnar electrodes are solved.

[0121] In this embodiment, as Figure 4 As shown, several filter elements are arranged inside the filtration chamber 16. Their functions are: first, to filter and intercept anode debris and oxidation products that fall off during the operation of the first replacement chamber 6, the second replacement chamber 7, and the third replacement chamber 8, as well as during the replacement of the anode 9; second, to efficiently intercept silt and suspended impurity particles carried in the seawater, while protecting the subsequent pipelines and equipment from wear and tear, and ensuring the long-term stable operation of the seawater desalination unit.

[0122] In this embodiment, as Figure 3 As shown, the anode storage chamber 11 stores new anodes 9. The anode storage chamber 11 is located above the anodes 9, and it stores 3 to 4 spiral-shaped new anodes 9 inside. The new anodes 9 are separated by partition plates. When the intelligent control system 4 determines that the anodes 9 need to be replaced through potential monitoring and thickness detection, the anode storage chamber 11 pops out new anodes 9 to fill and replace the old anodes 9.

[0123] The system is primarily driven by an external power source, with the spontaneous reaction of the galvanic cell serving only as an auxiliary energy-saving measure (it does not participate in the core electron supply when the anode potential is too low), as detailed below:

[0124] 1. When the anode 9 has sufficient activity (i.e., the anode working potential WCP ≤ -1.55V (vsSHE, relative to the standard hydrogen electrode)):

[0125] At this point, the anode 9 has high surface activity and a negative potential, forming a stable potential difference with the cathode 10, enabling it to spontaneously initiate a galvanic cell reaction to provide core electrons. Therefore, the system can appropriately reduce the external current or utilize the galvanic cell reaction to supplement energy, achieving energy saving.

[0126] 2. When the activity of anode 9 decays (i.e., the anode operating potential WCP > -1.55V):

[0127] At this point, an oxide film, slime coverage, or localized passivation appears on the surface of anode 9, causing a positive potential shift, reduced electron release capacity, and a significant weakening of the galvanic cell reaction. Therefore, the system shuts down the galvanic cell auxiliary mode and immediately activates power system 2, precisely compensating for electron supply through external current to prevent reaction failure.

[0128] Basic approach: Always rely on external current regulation to ensure stable system operation; only allow spontaneous reaction of the galvanic cell as an auxiliary energy-saving means when the anode potential activity is sufficient and the potential is stable; when the anode potential activity decays and the potential shifts positively, rely entirely on external current to drive the system and reduce the participation of spontaneous reaction in the core electron supply.

[0129] In this embodiment, the cathode 10 and anode 9 are designed with matching helical parameters, such as pitch, diameter, and direction of rotation, to create continuous disturbance of seawater within the helical flow channel. Simultaneously, the potential difference between the anode 9 and cathode 10 spontaneously forms a galvanic cell circuit, realizing Fe... 3+ Mn 2+ Targeted conversion and efficient removal. The top of the anode 9 is equipped with a quick-plug terminal, which is connected to the current collector 12 by a snap-fit. The current is collected from the top of each spiral anode 9 to the current collector 12, realizing series conduction of each spiral anode 9 and ensuring uniform current distribution.

[0130] In practice, to further improve the system's compactness and processing efficiency, the anode 9 and cathode 10 can be designed as built-in structures and installed inside the seawater pipeline to reduce the volume of the reaction chamber 5.

[0131] In this embodiment, the power supply system 2 adopts an adjustable DC power supply, which can provide stable DC voltage and current. The output voltage range is 0-10V, and the output current range is 0-20A, which can be adjusted according to the actual operating requirements of the electrochemical ion exchange reactor 1.

[0132] The power supply regulation module precisely regulates the output voltage and current of the DC power supply according to the instructions of the intelligent control system 4. It employs pulse width modulation technology to achieve rapid response and precise control of the power output, ensuring stable operation of the reactor under different operating conditions.

[0133] In practice, the power supply system 2 can also use a pulse power supply to provide high-energy pulse current in a short time, thereby improving the dissolution rate of the anode 9 and the reduction capacity of the cathode 10, and thus improving the ion removal efficiency.

[0134] In this embodiment, the monitoring system 3 includes a water quality monitor, a potential monitor, and a flow rate monitor;

[0135] Among them, the water quality monitor is used to monitor the concentration of iron, manganese and aluminum ions in seawater in real time. Spectrophotometer or ion chromatograph has high detection accuracy and can promptly report changes in water quality. Furthermore, water quality monitoring can use ion-selective electrodes or multi-parameter online water quality analyzers to monitor the ion concentration of iron, manganese and aluminum ions in real time. The potential monitor in monitoring system 3 can indirectly assess the potential environment of the aluminum alloy heat exchange tube bundle.

[0136] The potential monitor tracks the potential changes of the anode 9 and cathode 10 to ensure that the electrodes operate within their normal potential range. Potential monitoring allows for assessment of the electrode reaction state and the system's operational stability.

[0137] The flow monitoring device uses an electromagnetic flow meter or an ultrasonic flow meter to monitor the seawater flow rate in real time. By monitoring the flow rate, the residence time of seawater in the reactor is controlled to ensure the full progress of the ion exchange reaction.

[0138] In this embodiment, the intelligent control system 4 includes a controller, a sensor module, and a data analysis module.

[0139] The controller employs a programmable logic controller (PLC) to adjust the output parameters of the power supply system 2 in real time based on the data collected by the monitoring system 3. For example, when the water quality monitor detects an increase in the concentration of iron ions in seawater, the controller automatically increases the output current of the power supply to enhance the dissolution rate of the anode 9 and the reduction capacity of the cathode 10, thereby removing iron ions more effectively.

[0140] The sensor module includes a water quality sensor, a potential sensor, and a flow sensor, which are responsible for collecting data on ion concentration, electrode potential, and seawater flow rate in seawater and transmitting them to the controller.

[0141] The data analysis module analyzes and processes the data collected by the sensors to establish ion concentration change models and reaction efficiency models. By analyzing these models, the operating status and ion removal efficiency of the electrochemical ion exchange reactor 1 are predicted, providing a reference for adjusting the controller parameters.

[0142] In this embodiment, a closed-loop detection system is constructed through three dimensions: iron and manganese ion concentration detection, electrode potential detection, and anode 9 consumption monitoring.

[0143] (1) The iron and manganese removal efficiency directly reflects the effectiveness of the electrode reaction, and its change is strongly correlated with the electron supply capacity (potential, activity) of anode 9 and the catalytic activity of cathode 10.

[0144] (2) The potential state of anode 9 reflects its electron release activity, that is, its oxidation capacity, and the degree of consumption reflects the remaining electron supply capacity.

[0145] Relationship judgment method: When the iron and manganese removal rate decreases, the potential of anode 9 and the consumption data are used to distinguish whether it is "anode 9 activity decay", "anode 9 capacity insufficiency" or "cathode 10 catalytic failure", thereby triggering the "external current compensation" or "anode 9 replacement" command.

[0146] I. Potential Correlation Detection and Calculation Method for Iron and Manganese Removal Efficiency

[0147] (I) Core Computational Logic

[0148] The iron and manganese removal efficiency is calculated directly using the "concentration difference between inlet and outlet," while simultaneously verifying the sufficiency of the reaction by combining the "concentration at the midpoint of the reaction zone with the cathode potential," thus avoiding misjudgment based solely on inlet and outlet data.

[0149] Formula for single ion removal rate:

[0150] Single ion removal rate = [(inlet concentration - outlet concentration) / inlet concentration], that is:

[0151] (Formula 1);

[0152] Where, η X The single ion removal rate is X, where X represents iron or manganese ions, and C represents the single ion removal rate. xin For single ion inlet concentration, C xout This refers to the single-ion outlet concentration.

[0153] Reaction sufficiency verification: When the concentration C at the midpoint of the reaction zone... xmid ≤0.3×C xin When C is constant, it indicates that the reaction proceeds uniformly along the spiral flow path; if C xmid >0.5×C xin If the cathode potential of the corresponding replacement chamber deviates from its exclusive optimal range (see the linkage analysis of each replacement chamber for the specific range), it is determined to be "abnormal potential regulation" and the state of the associated anode 9 needs to be adjusted.

[0154] (II) Analysis of the correlation between potential and removal efficiency

[0155] The cathode potential is a "key regulatory signal" for the iron ion reduction reaction and the manganese ion reaction in the locally weakly alkaline region on the Ni-Co-P cathode surface. The weakly alkaline condition refers to a pH of 8-9. Its correlation with removal efficiency was experimentally calibrated, taking into account the reaction characteristics and specific potential ranges of each replacement chamber, as detailed below:

[0156] First replacement chamber 6:

[0157] Optimal range: cathode potential E cathode =+0.64V~+0.76V, at this point there is no hydrogen evolution side reaction, Fe 3+ It can achieve targeted priority restoration.

[0158] Abnormal range 1: E cathode > +0.76V, positive bias, Fe 3+ Insufficient thermodynamic driving force for reduction is mostly due to insufficient supply of 9 electrons to the anode (activity decay or positive potential shift). Abnormal range 2: E cathode <+0.64V, biased towards negative, prone to premature Fe triggering 2+Restore, disrupt the step-by-step targeted restoration logic, η Fe3+ Although there is no significant decrease, it will lead to an increase in Fe in the subsequent second replacement chamber 7. 2+ To remove the increased load, the cathode potential needs to be adjusted upwards to return to the optimal range.

[0159] Second replacement chamber 7: Optimal range: cathode potential E cathode = -0.4V to -0.6V, at which point the hydrogen evolution side reaction accounts for <5%; Abnormal range 1: E cathode >-0.4V, biased positive, insufficient thermodynamic driving force for ferrous ion reduction, mostly due to insufficient supply of 9 electrons at the anode; Abnormal range 2: E cathode <-0.6V, slightly negative, hydrogen evolution reaction intensifies, η Fe The improvement is not significant, but the consumption of anode 9 is accelerated, and the current needs to be suppressed; Third replacement chamber 8: Optimal range: cathode potential E cathode =+0.435V~+0.565V, no hydrogen evolution side reaction, Mn 2+ It can be efficiently oxidized to MnO2 precipitate; Abnormal range 1: E cathode <0.435V, slightly negative, easily causing the newly formed MnO2 to undergo reverse reduction and dissolution; at the same time, the driving force for electric field migration is weakened, and the oxidation reaction of manganese ions is hindered, η Mn If the value decreases, the cathode potential needs to be adjusted upwards to return to the optimal range. Abnormal range 2: E cathode >0.565V, positive bias, the electrode polarization is too low, the catalytic oxidation reaction kinetics are insufficient, the MnO2 generation rate slows down and the conversion is insufficient, resulting in a decrease in manganese removal efficiency, mostly due to insufficient 9 electron supply at the anode.

[0160] By monitoring the cathode potential and iron / manganese removal rate in real time, the core reason for the inefficient reaction can be quickly identified: if η X Decrease and E cathode Positive bias → Anode 9-side problem; if η X Decrease and E cathode Negative bias → Cathode 10 side or flow field problem.

[0161] II. In-depth detection of the 9th state of the anode (dual dimensions of potential and consumption)

[0162] (I) Anode Potential Detection and Activity Assessment

[0163] The potential of anode 9 directly reflects its electron release capability. It is necessary to compare the two potentials, "open circuit potential (OCP)" and "working potential (WCP)," to eliminate environmental interference.

[0164] Potential reference value (anode 9 material is 5052 aluminum alloy, seawater condition);

[0165] First replacement chamber 6:

[0166] Initial open-circuit potential OCP0 = -1.55V to -1.60V (no oxide film on the surface, optimal activity, matching the spontaneous dissolution characteristics of the anode); The initial operating potential WCP0 is -1.55V to -1.60V (the anode in this replacement chamber maintains an open circuit potential, and electrons are supplied only through the galvanic cell reaction; the operating potential is consistent with the open circuit potential).

[0167] Second replacement chamber 7: Initial open-circuit potential OCP0 = -1.55V to -1.60V (optimal activity when there is no oxide film on the surface); The initial operating potential WCP0 is -1.50V to -1.58V (normal electron release state after forming a circuit with cathode 10).

[0168] Third replacement chamber 8: Initial open circuit potential OCP0 = -1.55V to -1.60V (the anode material is 5052 aluminum alloy, the initial open circuit potential is the same as other replacement chambers, only the working potential is adjusted according to the electron requirements); The initial operating potential WCP0 = -1.15V to -1.30V (after forming a circuit with cathode 10, it catalytically activates dissolved oxygen in the water to form superoxide radicals, Mn 2+ MnO2 is rapidly generated by losing electrons under locally weakly alkaline conditions, where the weakly alkaline conditions refer to a pH of 8-9.

[0169] Matched with the standard electrode potential for the reaction of anode 9.

[0170] The pattern of potential changes and the judgment logic are shown in Table 1: Table 1. Potential Change Patterns and Judgment Logic

[0171]

[0172] The positive shift in the anode potential at point 9 is essentially due to "increased resistance to electron release," meaning either a high-resistivity oxide film forms on the surface.

[0173] (Aluminum ions hydrolyze to form Al(OH)3 gel), or the slime prevents the anode 9 from contacting the seawater. The difference between OCP and WCP can be used to distinguish between them: if OCP is normal but WCP is positive → slime or oxide film (surface problem); if both OCP and WCP are positive → anode 9 is consumed or its activity is reduced (internal problem).

[0174] (II) Anode 9 Consumption Level Detection and Remaining Life Prediction

[0175] The thickness of the spiral aluminum alloy anode 9 cannot be directly measured along its entire length. This solution employs a dual verification method of direct thickness detection and dissolution rate calculation to ensure accurate consumption assessment.

[0176] Direct thickness measurement: Select the inlet, middle section and outlet of the anode 9 spiral to install test samples and measure the remaining thickness h of anode 9 (initial thickness h0=20mm).

[0177] The formula for calculating the remaining capacity factor k is as follows:

[0178] (Formula 2);

[0179] Dissolution rate calculation:

[0180] Based on Faraday's law:

[0181] Faraday's First Law: The mass m (in grams) of the substance dissolved at an electrode is directly proportional to the total charge Q (in cubic centimeters) passing through the electrode, that is:

[0182] (Formula 3);

[0183] (K is the electrochemical equivalent, which is related to the type of substance);

[0184] Faraday's Second Law:

[0185] (Formula 4);

[0186] (M is the molar mass of the substance, n is the number of electrons transferred, and F is the Faraday constant);

[0187] Total battery power:

[0188] (Formula 5);

[0189] (I is the average current of the anode 9 circuit, in A; t is the energizing time, in s).

[0190] Step 1: Calculate the mass m of anode 9 dissolved:

[0191] Based on the above laws, the formula for the mass of dissolution is:

[0192] (Formula 6);

[0193] Where η (current efficiency, 0.9~0.95): In actual working conditions, in addition to the main reaction in which aluminum atoms lose 3 electrons to generate aluminum ions, a small amount of hydrogen evolution side reaction may occur at anode 9. Therefore, the current efficiency is used to correct the proportion of the amount of electricity that effectively participates in the dissolution reaction (the default value is η=0.92, which can be calibrated experimentally).

[0194] Step 2: Calculate the volume of dissolution, V:

[0195] According to the density formula:

[0196] (Formula 7);

[0197] The volume of solution obtained by deformation:

[0198] (Formula 8);

[0199] Units for parameters are consistent: ρ = 2.68 g / cm³ 3 (Density of aluminum alloy), M = 27 g / mol, therefore the unit of V is cm. 3 .

[0200] Step 3: Calculate the thickness Δh of the dissolved material:

[0201] The dissolution of anode 9 is uniform corrosion (ideal state), and the dissolution volume is equal to "effective reaction area × dissolution thickness", that is:

[0202] (Formula 9);

[0203] Transformed to:

[0204] (Formula 10);

[0205] Step 4: Calculate the dissolution rate and convert the dissolution rate v to mm / month:

[0206] (1) The dissolution rate v is defined as "the thickness of dissolution per unit time", so:

[0207] (Formula 11);

[0208] (2) The unit for converting the dissolution rate v is mm / month:

[0209] Key points for unit conversion:

[0210] The effective reaction area of ​​anode 9 is S = 0.5 m². 2 =0.5×10 4 cm 2 (1m) 2 =10 4 cm 2 );

[0211] The dissolution thickness Δh is in cm and needs to be converted to mm (1cm=10mm).

[0212] The unit of time t needs to be converted from "seconds" to "months" (1 month ≈ 30 days × 24 hours × 3600 seconds = 2.592 × 10). 6 s), we get:

[0213] Definition of dissolution rate: (Formula 12);

[0214] (Formula 13);

[0215] Step 5: Substitute the parameters to simplify the formula:

[0216] Given the parameters (M=27, n=3, F=96500, ρ=2.68, S=0.5×10), 4 Substituting η=0.92, we calculate the constant term: constant term = [27×0.92×10×(2.592×10 6 )] / [(3×96500×2.68×(0.5×10 4 )]≈0.166;

[0217] Final simplified formula for engineering applications:

[0218] (Formula 14);

[0219] The dissolution rate v is measured in mm / month. When the current I is measured in A, the dissolution rate can be calculated directly and quickly (e.g., when I = 5A, v ≈ 0.166 × 5 = 0.83 mm / month; in actual operating conditions, the current fluctuations need to be taken as the average value).

[0220] By combining the real-time current I, the remaining life T (months) of anode 9 can be dynamically calculated:

[0221] (Formula 15);

[0222] (h) min =3mm, minimum safe thickness, to avoid exposing the anode 9 support structure).

[0223] The relative solubility coefficient k1' is derived based on the remaining capacity coefficient k:

[0224] Where: Δh 累计 =h0-h (cumulative dissolved thickness, mm); h0 is the initial thickness; h is the remaining thickness, obtained by direct detection;

[0225] k (remaining capacity coefficient) = h / h0;

[0226] (Formula 16);

[0227] The relative solubility coefficient k2' is derived based on the dissolution rate:

[0228] Meanwhile, the cumulative dissolved thickness is also:

[0229] (Formula 17);

[0230] (T) 使用 Given that anode 9 has been in operation for [number] months, the relative solubility coefficient k2′ is derived based on the dissolution rate v.

[0231] (Formula 18);

[0232] Dual verification logic: The relative solubility coefficient k1' derived from the remaining capacity coefficient k is compared with the relative solubility coefficient k2' derived from the dissolution rate to verify the consistency of the data. If the deviation between the two is ≤ ±5%, it indicates that the consumption assessment is accurate, and the relative solubility coefficient k' adopts the average of the two. If the deviation is > 5%, the cause should be investigated (such as fluctuations in current efficiency η, local corrosion causing the directly tested sample to be unrepresentative, current measurement error, etc.).

[0233] The lifetime intervals based on k and k' are shown in Table 2:

[0234] Table 2. Lifetime interval division based on k and k'

[0235]

[0236] The uneven consumption of anode 9 is a key issue in the spiral structure. The strong water flow at the inlet leads to a 15%–20% higher dissolution rate than at the outlet, causing anode 9 in a certain coaxial spiral nested component to fail first. By using multi-point thickness detection and dissolution rate calculation, the "weak point" can be located, allowing for the replacement of anode 9 only in a single coaxial spiral nested component, rather than replacing all anode 9 in the entire coaxial spiral nested module, thus reducing maintenance costs.

[0237] It should be noted that while formula 14 in the instruction manual, v≈0.166I, is derived from theoretical formulas, in practice, the dissolution rate v is not a fixed value. Instead, it dynamically changes based on current density, seawater flow rate, corrosive environmental conditions, and the state of the oxide film on the anode 9 surface. The remaining lifespan T directly depends on the value of v. Therefore, different operating conditions result in different dissolution rates v, leading to differences in the corresponding remaining lifespan T. This difference is the discrepancy between theory and practice. In practical applications, a single anode 9 is typically replaced approximately every year, with an overall replacement cycle of 3-4 years (including anode replacement). This varies slightly depending on the equipment's commissioning time and the volume of water treated, but generally, a 3-4 year maintenance and replacement cycle is considered a standard procedure.

[0238] It should be noted that electrodes are installed inside the first, second, and third replacement chambers, with different potentials set for each electrode to perform independent electrochemical treatment of iron and manganese ions. Utilizing the difference in standard electrode potentials for the redox reactions of different ions, and through intelligent staged control of the cathode potential, combined with the kinetic optimization of the Ni-Co-P catalytic layer on cathode 10, stepwise reduction of ferric ions to ferrous ions, and then from ferrous ions to elemental iron, as well as the reduction of Mn... 2+ The process involves a staged reaction of oxidation to generate MnO2, followed by removal through flocculation and co-precipitation. Simultaneously, through synergistic control of anodic potential and design to suppress side reactions, the electrochemical oxidation-reduction-catalytic adsorption synergistic process is ensured to be efficient and controllable.

[0239] III. Circuit Optimization:

[0240] (a) Optimized circuit for iron ion reduction potential:

[0241] The iron ion reduction potential optimization circuit targets "Fe 3+ →Fe 2+ "Fe" 2+ To address the differentiated requirements of the two-step reaction for Fe element, a step-by-step closed-loop control design is adopted, as detailed below:

[0242] Reduction peak potential (Epc) determination: Cyclic voltammetry (scan rate 50 mV / s, potential window -1.0 V to +1.0 V) was used to determine the reduction peak potentials of the two-step reaction on the surface of the Ni-Co-P catalytic cathode: Fe 3+ →Fe 2+ The reduction peak potential (Epc1) of Fe is +0.65V to +0.75V (close to the standard reduction potential of +0.77V). 2+ →Reduction peak potential (Epc2) of Fe element: -0.50V to -0.60V (close to the standard reduction potential of -0.44V).

[0243] Step-by-step constant potential control:

[0244] First replacement chamber 6 (Fe) 3+ →Fe 2+ When the original potential does not meet the reaction requirements, the cathode potential is mainly stabilized at Epc1±10mV (+0.64V~+0.76V) by the PID controller. This range is negative for Fe. 3+ / Fe 2+ The standard reduction potential satisfies the thermodynamic criterion of "cathode potential ≤ ion standard reduction potential", ensuring Fe 3+ It preferentially reduces hydrogen evolution; at the same time, this potential range differs significantly from the standard reduction potential of the hydrogen evolution reaction, and is far positive than the initiation potential threshold of the hydrogen evolution reaction, thus thermodynamically completely suppressing the occurrence of hydrogen evolution side reactions.

[0245] Second replacement chamber 7 (Fe) 2+ →Elemental Fe): The cathode potential is stabilized at Epc2±10mV (-0.51V to -0.61V) using a PID controller. This range is negative for Fe. 2+ The Fe standard reduction potential is satisfied with the thermodynamic requirements and is controlled within the optimal range (-0.4V to -0.6V) where the proportion of hydrogen evolution side reaction is <5%.

[0246] Closed-loop control mechanism: Real-time linkage between the circuit and the monitoring system's potential sensor and water quality sensor: The potential sensor collects the real-time cathode potential; when it deviates from the set range by ±5mV, the PID controller dynamically adjusts the output potential with a response time ≤100ms; the water quality sensor monitors the Fe at the inlet and outlet of the replacement chamber. 3+ Fe 2+ Concentration triggers coordinated adjustment of the anode potential (e.g., reducing the anode operating potential by 0.02V to 0.03V) to enhance electron supply.

[0247] (II) Optimization of the environmental potential for manganese ion flocculation and precipitation:

[0248] For Mn 2+ Oxidative flocculation and precipitation characteristics, using "Fe 2+ The design incorporates a "mild pre-oxidation process to regulate the aquatic microenvironment, a Ni-Co-P catalytic layer to efficiently activate dissolved oxygen in the water, pulsed potential regulation, and Al(OH)3 flocs to capture and precipitate" as follows:

[0249] Preprocessing-mediated mechanism:

[0250] Third replacement chamber 8 (Mn) 2+ →MnO2→flocculation and precipitation): The inlet water in the third replacement chamber 8 carries the Fe generated in the previous reaction. 2+ By introducing a small amount of air into the replacement chamber, the Fe... 2+ The oxidation reaction; simultaneously, the 2% Ru doped in the Ni-Co-P catalyst layer can catalyze the activation of dissolved oxygen to generate highly active O2. -This reactive oxygen species will Mn 2+ Efficient oxidation to MnO2, while Al at the anode 3+ In a weakly alkaline environment, a network of Al(OH)3 flocs is generated, which captures MnO2 to form a complex co-precipitate.

[0251] Manganese oxidation characteristic potential (Epc) Mn Interval determination: Cyclic voltammetry (scan rate 50 mV / s, potential window 0.2 V to +0.8 V) was used, combined with MnO2 / Mn 2+ The corresponding redox characteristics of Mn were used to determine 2+ The optimal characteristic potential range for efficient oxidation to MnO2 is +0.45V to +0.55V.

[0252] Pulse constant potential control:

[0253] Control objective: Based on the characteristic potential of manganese oxidation, the optimal control range for the cathode is set to +0.435V to +0.565V (vs SHE) to match a weakly polarized electric field environment. This satisfies the thermodynamic and kinetic requirements of manganese catalytic oxidation while avoiding insufficient oxidation kinetics due to a positive potential bias and reverse reduction of MnO2 due to a negative potential bias. Pulsed potential mode operation (duty cycle 1:5, frequency 100 Hz) is adopted. Intermittent electric field output can shorten the duration of strong polarization and effectively suppress residual Fe. 3+ Competitive reduction and weakening of interfacial polarization enrichment effects keep the proportion of cathode hydrogen evolution side reactions below 5%.

[0254] Matching PID dynamic closed-loop control: Real-time acquisition of cathode current density and linkage correction of pulse potential peak value, when current density > 12 A / m 2 The analysis indicated that the competitive reduction of iron ions was intensified, leading to a decrease in the peak potential by 0.02 V, which weakened the cathode's reduction capability. When the current density was <8 A / m... 2 The reaction was determined to be due to insufficient kinetic energy in the manganese oxidation reaction. The peak potential was increased by 0.01 V to enhance electric field migration and catalytic oxidation efficiency.

[0255] (III) Coordinated control mechanism of anode and cathode potentials

[0256] The potential optimization for both iron and manganese ions is based on a synergistic control logic with the working potential (WCP) of the anode, ensuring a reasonable overall potential difference and efficient reaction.

[0257] Cooperative control logic (such as) Figure 6 (as shown)

[0258] First replacement chamber 6 (Fe) 3+ →Fe 2+The anode working potential is maintained at -1.55V to -1.60V, forming a potential difference of 2.24V to 2.31V with the cathode potential (+0.64V to +0.76V), which satisfies the low electron requirement while avoiding excessive dissolution of the anode. Second replacement chamber 7 (Fe) 2+ →Elemental Fe): The anode working potential is adjusted to -1.50V to -1.58V, forming a potential difference of 0.97V to 0.99V with the cathode potential (-0.51V to -0.61V), thus balancing the reaction efficiency and anode stability; The third replacement chamber 8 (Mn species-oriented transformation): The anode working potential is adjusted to -1.15V to -1.30V, forming a potential difference of 1.715V to 1.735V with the cathode potential of +0.435V to +0.565V. This provides sufficient thermodynamic drive for the directional transformation and flocculation precipitation reaction of MnO2 in the system, while ensuring the stable dissolution of aluminum ions and synergistically achieving efficient removal of manganese ions.

[0259] Linkage control trigger: When the cathode potential deviates from the set range of ±5mV for 30s, the intelligent control system 4 first makes small adjustments to the anode potential within the inherent stable potential range of the anode in the corresponding chamber (±0.02V each time). When the anode potential has reached the upper or lower limit of the chamber range, or when the cathode potential still has not returned to the set range after the adjustment, the cathode potential is then finely adjusted. The anode of each chamber is strictly limited to its own preset working range: the first replacement chamber 6 (-1.55V to -1.60V), the second replacement chamber 7 (-1.50V to -1.58V), and the third replacement chamber 8 (-1.15V to -1.30V), maintaining the established potential difference and the thermodynamic conditions of the step reaction in each chamber.

[0260] IV. Electrode control strategy (which involves external current compensation and anode 9 replacement prompts), as follows:

[0261] (a) External current compensation mechanism

[0262] 1. Compensation trigger condition (meeting any one of the following):

[0263] The remaining capacity coefficient k of anode 9 is less than or equal to 0.2 (or the remaining lifespan T is less than or equal to 2 months). The electron supply capacity of the anode dissolution is reduced and cannot meet the electricity demand for iron ion reduction.

[0264] When the anode working potential is greater than the upper limit of the range, the activity decreases and cannot be returned to the stable range by fine-tuning the anode potential within 24 hours.

[0265] Potential E of composite catalytic cathode (10) cathode When the optimal operating range is exceeded, scale buildup or activity decay occurs on the cathode surface. Even after ultrasonic cleaning, the abnormal potential does not improve, and the iron ion reduction and manganese ion oxidation precipitation conditions become unstable.

[0266] 2. Compensation current design (dynamically adjustable to avoid hydrogen evolution side reactions):

[0267] Compensation power supply: Turn on power system 2, low voltage DC auxiliary power supply (output voltage 0~5V, current 0~20A), positive terminal connected to the collector busbar in collector box 12, negative terminal connected to fixed shaft 14 (forming "dual electron supply" with anode 9), to supplement electrons for the reduction reaction of iron ions at cathode;

[0268] Current regulation logic: Compensation current I compensate The "electronic supply and demand balance" constraint must be met, namely:

[0269] (Formula 19);

[0270] I anode (t) represents the spontaneous dissolution current (A) at time t, derived from I anode =FvS Derivation (v is the anolyte dissolution rate (in m / s), S is the effective anolyte area (in m²) 2 (where F is the Faraday constant).

[0271] in:

[0272] (Formula 20);

[0273] (n) Fe n represents the number of electrons transferred by the iron ion; Mn n represents the number of electrons transferred by the manganese ion. Fe =3, Fe 3+ →Fe 2+ →Fe gains 3e - ;n Mn =2,Mn 2+ →MnO2 loses 2e - Q represents seawater flow rate (unit: m³ / s). 3 / h); C Fein Iron ion inlet concentration (unit: mol / m³) 3 ); C Mnin Manganese ion inlet concentration (unit: mol / m³) 3 ); =Electron utilization efficiency, taken as 0.95).

[0274] I required (t) is the minimum current (A) required for the iron-manganese redox reaction at time t, calculated using formula 20:

[0275] I required =FQ(n Fe C Fein- n Mn CMnin ) / 3600η e

[0276] Constraints: The cathode potential E must be monitored in real time during the compensation process. cathode And maintain it within the optimal operating range; if the cathode potential is higher than the upper limit of the optimal range, it indicates that the electron supply is excessive, and I is gradually reduced by 5% at a time. compensate The cathode potential is increased until it returns to the optimal range, suppressing the hydrogen evolution side reaction. If the cathode potential is lower than the lower limit of the optimal range, it indicates insufficient electron supply. The compensation current is gradually increased to pull the anode back to the activation region of -1.6 to 1.65V, restoring aluminum ion dissolution and ensuring the normal progress of the iron and manganese ion precipitation reaction.

[0277] 3. Verification of compensation effect:

[0278] After compensation is initiated, monitor in real time: ①η Fe ≥88%, η Mn ≥82% (target value); ② Anode working potential WCP returns to the stable range; ③ Cathode potential E cathode The current compensation current is maintained within the optimal range if all three conditions are met simultaneously; otherwise, it is dynamically adjusted.

[0279] (II) Anode 9 Replacement Prompt and Execution Mechanism

[0280] 1. Change the trigger condition (meeting any of the following):

[0281] The residual capacity coefficient k of anode 9 is less than 0.15 or the relative solubility coefficient k' of anode 9 is greater than 0.85;

[0282] Remaining lifespan T < 0 (safe thickness exceeded);

[0283] If the anode working potential WCP remains above the upper limit of the range for more than 24 hours, and the potential still cannot return to the stable range after fine-tuning the anode working potential through the intelligent control system, it is determined that the anode activity has completely decayed.

[0284] The magnetostrictive sensor detected that the local thickness of anode 9 is ≤3mm (minimum safe thickness), which poses a risk of structural fracture.

[0285] 2. Change prompts and execution process:

[0286] (1) Early warning stage (0.15≤k<0.2 or 0.8<k'≤0.85): The system issues an "Anode 9 replacement warning", displays the remaining lifespan and the optimal replacement window (avoiding the period of high seawater turbidity), and simultaneously pushes a spare parts procurement reminder;

[0287] (2) Emergency alert stage (k < 0.15 or k' > 0.85): The system issues an audible and visual alarm, locks the "replacement priority", and displays the anode 9 that needs to be replaced (based on multi-point detection to locate weak points).

[0288] (3) Replacement execution: The anode storage chamber 11 stores 3 to 4 new anodes 9 in layers, which can realize the automatic replacement of anodes 9 first. When all the new anodes 9 stored in the anode storage chamber 11 are used up, new anodes 9 are manually added to the anode storage chamber 11.

[0289] In this embodiment, the automatic replacement process of anode 9 is as follows:

[0290] The anode storage chamber 11 stores 3 to 4 new anodes 9 stacked together. The telescopic controller 13 located above the new anodes 9 can independently or interlock the process of the intelligent control system 4 to carry out the online replacement operation of the anodes 9 in the anode storage chamber 11 through the steps of axial compression, limit fixation, and extension.

[0291] Specifically, when the intelligent control system 4 determines that the entire anode 9 needs to be replaced through potential monitoring and thickness detection, the process is automatically initiated: First, the front gate is closed to isolate the flow channel on the replacement chamber side where the anode to be replaced (old anode 9) is located, while the rear gate remains open to form a valve cavity; then, the residual seawater in the replacement chamber where the anode to be replaced 9 is located is emptied and the pressure is balanced to ensure that there is no risk of leakage during operation; finally, the axial fixation of the old anode 9 is released, and its conductive connection with the current collector box 12 is disconnected. After the conductive connection is disconnected, the current collector box 12 automatically switches to the "standby insulation state" to prevent short-circuit current from being generated due to accidental contact during the replacement process. A retaining ring is provided at one end of the anode storage chamber 11 away from the telescopic controller 13. This ring is used to prevent the new anode 9 from being compressed and deformed by external force when the anode storage chamber 11 moves downward to replace the new anode 9. A fixing groove is provided at the other end to fix the new anode 9. The fixing shaft 14 is an axial sliding support mechanism for the new anode 9. A limiting locking pin 15 is provided at the bottom of the fixing shaft 14 to engage with the anode 9. A locking through hole is provided at one end of the anode 9 to engage with the limiting locking pin 15. The telescopic controller 13 is connected to the top of the anode storage chamber 11. When the telescopic controller 13 extends axially, it pushes the anode storage chamber 11 to the position of the limit locking pin 15. The snap-fit ​​hole on the new anode 9 in the anode storage chamber 11 engages with the limit locking pin 15, fixing one end of the new anode 9. At the same time, during the pushing process, the old anode 9 is compressed downward to the limit locking pin 15 and disengaged from the limit locking pin 15, causing the old anode 9 to be compressed below the limit locking pin 15. When the telescopic controller 13 retracts, it brings the anode storage chamber 11 back to its original position. Under the pull of external force, the new anode 9 deforms and disengages from the limiting effect of the fixing groove. At the same time, the new anode 9, which is engaged with the limit locking pin 15, loses the external force from the anode storage chamber 11 and recovers its spiral structure under the action of elastic deformation force, that is, it extends upward along the fixed axis 14, completing the replacement process of the anode 9. The replacement process employs both mechanical positioning and electrical performance verification to ensure the operational stability of anode 9. After the new anode 9 reaches the preset position, the limiting locking pin 15 of the fixed shaft 14 pops out to achieve axial fixation. The intelligent control system 4 initiates a small current test to detect the potential difference of each spiral segment of the new anode 9, ensuring uniform current distribution. Subsequently, the elastic conductive end of the current collector box 12 automatically pops out and tightly connects with the conductive connector of the new anode 9, restoring circuit continuity. At this point, the automatic replacement process of anode 9 is complete. The old anode 9, compressed below the limiting locking pin 15, continues to contact with seawater as an auxiliary anode 9 and participates in the reaction, gradually corroding and breaking off from the coaxial spiral nested structure assembly, and finally being intercepted and discharged through the filter element of the filter chamber 16.

[0292] In this embodiment, the process of manually replenishing the new anode 9 to the anode storage chamber 11 is as follows:

[0293] Manual replenishment applies to the first, second, and third replacement chambers. The top of the electrochemical ion exchange reactor 1, the sidewall of the second replacement chamber 7, and the sidewall of the third replacement chamber 8 can be opened and closed. If the coaxial spiral nested structure assembly in the first replacement chamber 6 needs to be replenished with new anode 9 to the anode storage chamber 11, the electrochemical ion exchange reactor 1 can be opened from the top to replenish the anode storage chamber 11 with new anode 9. If the coaxial spiral nested structure assembly in the second replacement chamber 7 needs to be replenished with new anode 9 to the anode storage chamber 11, the electrochemical ion exchange reactor 1 can be opened from the sidewall of the second replacement chamber 7 to replenish the anode storage chamber 11 with new anode 9. If the coaxial spiral nested structure assembly in the third replacement chamber 8 needs to be replenished with new anode 9 to the anode storage chamber 11, the electrochemical ion exchange reactor 1 can be opened from the sidewall of the second replacement chamber 7 to replenish the anode storage chamber 11 with new anode 9. When a new anode 9 needs to be added to the anode storage chamber 11, the electrochemical ion exchange reactor 1 can be opened from the side wall of the third replacement chamber 8 to add the new anode 9 to the anode storage chamber 11 (replacement time < 30 minutes; the first replacement chamber 6, the second replacement chamber 7, and the third replacement chamber 8 do not require simultaneous manual replenishment of the new anode 9 to the anode storage chamber 11; if one of them is in use, there is no need to shut down the entire reactor, only the corresponding flow channel is closed); the top of the electrochemical ion exchange reactor 1, the side wall of the second replacement chamber 7, and the side wall of the third replacement chamber 8 are all equipped with quick-sealing flanges and transparent observation windows, and the coaxial spiral nested structure assembly is equipped with independent positioning pins and conductive joints.

[0294] Specifically, the intelligent control system 4 closes the inlet and outlet valves of the flow channel corresponding to the replacement chamber where the coaxial spiral nested structure component of the new anode 9 is located, cutting off the seawater flow to that chamber; it opens the flow channel pressure relief valve and exhaust valve, and closes them after the pressure drops to atmospheric pressure; a detachable coaxial spiral nested structure module is installed inside the quick-sealing flange, and the spiral nested structure module is precisely matched with the mechanical limit sliders on the side walls of the first replacement chamber 6, the second replacement chamber 7, and the third replacement chamber 8. At the same time, the positioning reference line is projected through the perspective observation window alignment device to ensure accurate insertion and removal direction; if the replacement chamber where the coaxial spiral nested structure component of the new anode 9 is located is the first replacement chamber 6, the quick-sealing flange on the top of the ion exchange reactor 1 is opened; if the replacement chamber where the coaxial spiral nested structure component of the new anode 9 is located is the second replacement chamber 7 or the third replacement chamber 8, the quick-sealing flange on the side wall of the replacement chamber is opened. Rotate the coaxial spiral nested structure module until the coaxial spiral nested structure assembly containing the new anode 9 is rotated to the sealing flange and the viewing window. Insert a special wrench through the top (if the replacement chamber containing the coaxial spiral nested structure assembly containing the new anode 9 is the first replacement chamber 6) or side wall (if the replacement chamber containing the coaxial spiral nested structure assembly containing the new anode 9 is the second replacement chamber 7 or the third replacement chamber 8) of the ion exchange reactor 1. Sequentially remove the current collector box 12 and the telescopic controller 13. Fill the upper cover of the anode storage chamber 11 with the new anode 9, then reinstall the telescopic controller 13 and the current collector box 12. Next, close the quick-sealing flange, close the flow channel pressure relief valve, and open the exhaust valve. Open the inlet and outlet valves of the flow channel corresponding to the replacement chamber containing the coaxial spiral nested structure assembly containing the new anode 9 to connect the seawater flow in that chamber, completing the manual replenishment of the new anode 9 to the anode storage chamber 11. The automatic replacement process of the anode 9 can then continue.

[0295] (4) Calibration after replacement: After the new anode 9 is installed, check whether OCP and WCP have returned to their initial values, reset the remaining life calculation model synchronously, and start the initial operation (reduce the flow rate by 30% for the first 24 hours to avoid excessive flushing of anode 9).

[0296] It should be noted that when the iron and manganese elemental layers completely cover the Ni-Co-P catalyst layer of the cathode 10, and the catalyst layer of the cathode 10 is deactivated, it needs to be cleaned. For example, it can be cleaned by using a cleaning brush after opening the ion exchange reactor 1 during the process of manually replenishing the new anode 9 to the anode storage chamber 11.

[0297] Figure 5This is an embodiment of a nested structure of a first replacement chamber 6, a second replacement chamber 7, and a third replacement chamber 8. The first replacement chamber 6 is cylindrical, including a chamber wall, a top cover on the upper part of the chamber wall with a water inlet channel, and a bottom on the lower part of the chamber wall. A water outlet channel is located on the bottom near the chamber wall, allowing seawater to enter the second replacement chamber 7 close to the chamber wall. This ensures sufficient contact between the seawater and the electrode assembly. A boss structure is provided on the circumference of the bottom, allowing the boss of the first replacement chamber 6 to be embedded into the inner side of the chamber wall of the second replacement chamber 7 with an interference fit. At the same time, the bottom of the first replacement chamber 6 also becomes the top cover of the second replacement chamber 7. This nested structure is also used between the second replacement chamber 7 and the third replacement chamber 8. An air inlet channel is opened in the water outlet channel at the bottom of the second replacement chamber 7, which can introduce air or oxygen into the water outlet channel, so that the seawater mixes with the air or oxygen and flows into the third replacement chamber 8. The air inlet channel can be made of plastic pipe, which can form a circular channel. This channel surrounds the water outlet channel and is covered with small air outlet holes. The air pump blows air or oxygen into the air inlet channel, into the circular channel, and then out through the small holes and mixes with the seawater.

[0298] V. The intrinsic relationship between anode 9 consumption and potential, and the diagnosis of abnormalities

[0299] (I) The consumption-potential linkage law of anode 9 (core mechanism)

[0300] The "consumption-potential" relationship of anode 9 exhibits a non-linear change, which can be divided into three stages:

[0301] Initial stage (0-3 months, k=1.0-0.8): There is no oxide film on the surface of anode 9, WCP is stable at -1.58V to -1.5V, and the dissolution rate v is uniform (v≈0.8-1.0mm / month). At this time, consumption is weakly correlated with potential (potential remains basically unchanged, and consumption is uniform).

[0302] Mid-term stage (3-8 months, k=0.8-0.3): A thin oxide film forms on the surface, the WCP gradually shifts positive (for every 1 mm of thickness consumed, the potential shifts positively by ≈0.05 V), the dissolution rate v decreases slightly (v≈0.6-0.8 mm / month), at this time the consumption and potential are strongly positively correlated (the more it is consumed, the more positive the potential).

[0303] In the final stage (8-10 months, k=0.3-0.15): the oxide film thickens and detaches locally, the WCP fluctuation increases (±0.08v), the dissolution rate v accelerates (v≈1.2-1.5mm / month, caused by local scouring and oxide film detachment), and at this time the correlation between consumption and potential decreases (potential shifts positively but consumption is uneven).

[0304] In the intermediate stage, the consumption level can be directly estimated by potential (error < 5%). In the initial and final stages, thickness detection is required for correction to avoid misjudgment based on a single potential indicator.

[0305] This embodiment is fully compatible with the reaction chamber 5 structure of "outer spiral aluminum alloy anode 9 and inner stainless steel cathode 10". Through in-depth correlation analysis of potential detection, it realizes real-time monitoring and closed-loop control of iron and manganese removal efficiency and anode 9 status, solving the core pain points of traditional sacrificial anode 9 system: "difficult to judge status, replacement based on experience, and easy efficiency decay".

[0306] VI. Ensure the accuracy and operability of the consumption assessment for aluminum alloy anodes.

[0307] Calibration method for current efficiency η: Periodically calibrated by the "weighing method". Select a sample of the same material and size as anode 9, run it under actual operating current for a certain period of time, weigh it, and calculate the actual dissolved mass m. 实测 , with theoretical dissolution mass m 理论 .

[0308] Theoretical dissolution mass m 理论 Calculation formula;

[0309] (Formula 21);

[0310] In comparison,

[0311] (Formula 22);

[0312] It is calibrated every 6 months.

[0313] Dynamic correction of dissolution rate: When changes in seawater temperature and salinity cause fluctuations in current I, the "moving average method" (taking the average current over the past 72 hours) is used to calculate v, thereby improving the accuracy of remaining lifetime prediction.

[0314] The collaborative verification logic of k and k' is as follows: In daily operation, v and t, which are indirectly calculated, are used for dynamic early warning, and k, which is calculated by directly detecting the thickness, is used as the final judgment basis; when k enters the early warning range, the replacement time is planned based on the direct detection data.

[0315] This embodiment, through the above derivation, realizes a complete logical chain between absolute dissolution rate v, relative dissolution coefficient k', and remaining life T, and is deeply linked with direct thickness detection data to ensure the accuracy and operability of aluminum alloy anode 9 consumption assessment.

[0316] To further enhance understanding of this application, this application also provides a method for compensating the potential compensation device for protecting a low-temperature multi-effect seawater desalination device, which is compatible with the aforementioned potential compensation device for protecting a low-temperature multi-effect seawater desalination device. This method includes the following steps:

[0317] 1. Seawater pretreatment: The seawater first undergoes conventional pretreatment processes, such as filtration and sedimentation, to remove large particulate impurities and suspended solids in the seawater, so as to reduce the impact on the electrochemical ion exchange reactor 1.

[0318] 2. Electrochemical ion exchange reaction: Pretreated seawater enters the reaction chamber 5 of the electrochemical ion exchange reactor 1. Under the action of the DC electric field provided by the power supply system 2, the anode 9 undergoes an oxidation reaction, loses electrons and dissolves to produce aluminum ions; the cathode 10 receives electrons, causing iron ions in the seawater to undergo a reduction reaction on the cathode surface to produce elemental iron. Manganese ions are oxidized by dissolved oxygen under the local weak alkaline conditions of the cathode, and are converted into oxide precipitates. The weak alkaline conditions refer to a pH of 8-9. Deposition is achieved through the flocculation effect of aluminum ion hydrolysis products.

[0319] 3. Real-time monitoring and control: The monitoring system 3 monitors the ion concentration, electrode potential, and seawater flow rate parameters in seawater in real time and transmits the data to the intelligent control system 4. The intelligent control system 4 adjusts the output parameters of the power supply system 2 in real time based on this data to ensure the stable operation of the electrochemical ion exchange reactor 1 and the ion removal effect.

[0320] 4. Seawater discharge after treatment: The seawater, after electrochemical ion exchange treatment, flows out from reaction chamber 5 and enters the subsequent seawater desalination process. At this point, the content of iron and manganese ions in the seawater has been significantly reduced, effectively preventing corrosion of the aluminum alloy heat exchange tube bundle.

[0321] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit it. This application is not limited to the exact structures described above and illustrated in the accompanying drawings, and it should not be considered that the specific implementation of this application is limited to these descriptions. For those skilled in the art, various changes and modifications made without departing from the concept of this application should be considered to fall within the protection scope of this application.

Claims

1. A potential compensation device for protecting a low-temperature multi-effect seawater desalination device, characterized in that, It includes an electrochemical ion exchange reactor (1), a power supply system (2), a monitoring system (3) and an intelligent control system (4). The electrochemical ion exchange reactor (1) includes an anode (9), a cathode (10) and a reaction chamber (5). The anode (9) is an aluminum alloy electrode, which undergoes an oxidation reaction under the action of current, loses electrons and dissolves to produce aluminum ions; The cathode (10) is an electrode combining a stainless steel substrate and a Ni-Co-P catalyst layer. Under the action of an applied current, iron ions in seawater undergo a reduction reaction on the surface of the cathode (10). Manganese ions are oxidized by dissolved oxygen under the local weak alkaline conditions of the cathode and converted into oxide precipitates. The weak alkaline conditions refer to a pH of 8 to 9. Deposition is achieved through the flocculation effect of aluminum ion hydrolysis products. The reaction chamber (5) contains the anode (9) and the cathode (10), forming a closed reaction space.

2. The potential compensation device for protecting a low-temperature multi-effect seawater desalination device according to claim 1, characterized in that, The power supply system (2) is an adjustable DC power supply with an output voltage range of 0 to 10V and an output current range of 0 to 20A. The power regulation module of the power system (2) precisely regulates the output voltage and current of the DC power supply according to the instructions of the intelligent control system (4); The power system (2) adopts pulse width modulation technology to achieve fast response and precise control of power output.

3. The potential compensation device for protecting a low-temperature multi-effect seawater desalination device according to claim 2, characterized in that, The monitoring system (3) includes a water quality monitor, a potential monitor, and a flow monitor; The water quality monitoring instrument is a spectrophotometer or ion chromatograph, which monitors the concentration of iron ions, manganese ions and aluminum ions in seawater in real time and provides timely feedback on changes in water quality. The potential monitor monitors the potential changes of the anode (9) and cathode (10) to determine the reaction state of the electrodes and the operational stability of the system; The flow monitoring instrument is an electromagnetic flow meter or an ultrasonic flow meter, which monitors the flow rate of seawater in real time.

4. The potential compensation device for protecting a low-temperature multi-effect seawater desalination device according to claim 3, characterized in that, The intelligent control system (4) includes a controller, a sensor module, and a data analysis module; The controller is a programmable logic controller, which adjusts the output parameters of the power supply system (2) in real time based on the data collected by the monitoring system (3); The sensor module includes a water quality sensor, a potential sensor, and a flow sensor, which are responsible for collecting data on ion concentration, electrode potential, and seawater flow rate in seawater and transmitting them to the controller. The data analysis module analyzes and processes the data collected by the sensor to establish ion concentration change models and reaction efficiency models.

5. The potential compensation device for protecting a low-temperature multi-effect seawater desalination device according to claim 4, characterized in that, The reaction chamber (5) includes a first replacement chamber (6), a second replacement chamber (7), a third replacement chamber (8) and a filter chamber (16). The anode (9) is in the shape of a spiral corrugated plate structure and is uniformly arranged in the circumferential direction in the first replacement chamber (6), the second replacement chamber (7) and the third replacement chamber (8) to form a "ring array". The cathode (10) is a spiral corrugated plate and is arranged parallel to the anode (9); The anode (9) and cathode (10) adopt a coaxial spiral nested structure. The outer spiral anode (9) and the inner spiral cathode (10) are coaxially arranged in the first displacement chamber (6), the second displacement chamber (7), and the third displacement chamber (8) of the cylinder. Through the matching design of the spiral parameters, the seawater forms a continuous disturbance in the spiral flow channel. At the same time, the potential difference between the anode (9) and the cathode (10) spontaneously forms a galvanic cell circuit. The reaction chamber (5) is made of corrosion-resistant plastic material. Seawater flows into the reaction chamber (5) from one end. Under the action of the electric field, the cations in the seawater migrate to the cathode (10) and react. The treated seawater flows out from the other end.

6. The potential compensation device for protecting a low-temperature multi-effect seawater desalination device according to claim 5, characterized in that, The first replacement chamber (6), the second replacement chamber (7), and the third replacement chamber (8) are connected in series and adopt a nested structure with different potential gradients in the replacement chambers.

7. The potential compensation device for protecting a low-temperature multi-effect seawater desalination device according to claim 6, characterized in that: The potentials are all based on the standard hydrogen electrode. Specifically: in the first replacement chamber (6), the anode is maintained at an open circuit potential of -1.55V to -1.60V to meet the low electron requirements for the conversion of ferric ions into ferrous ions; in the second replacement chamber (7), the anode working potential is adjusted to -1.50V to -1.58V to meet the electron requirements for the conversion of ferrous ions into elemental iron; in the third replacement chamber (8), the anode working potential is adjusted to -1.15V to -1.30V to prevent excessive reduction of manganese oxides and ensure stable precipitation of manganese dioxide.

8. The potential compensation device for protecting a low-temperature multi-effect seawater desalination device according to claim 1, characterized in that, The electrochemical ion exchange reactor (1) is a built-in structure and is installed inside a seawater pipeline.

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