Analysis of Influencing Factors on the Efficiency of Electrochemical Scaling Equipment

Abstract

Electrochemical descaling devices have been widely used in the industrial field due to their broad applicability, convenience of operation, and cost-effectiveness. However, there are many factors that affect the descaling performance of electrochemical descaling devices, such as the selection of electrode materials, the shape and layout of the anode and cathode, the voltage and current of electrochemical equipment, the flow rate, temperature, and mineral content. Existing research has primarily focused on the influence of electrode materials and current density on descaling efficiency, while neglecting external factors such as water flow rate and temperature. In order to further explore the internal and external factors affecting the descaling performance of descaling machines, this study constructed an experimental platform for a descaling machine fouling device. Different voltages, currents, water flow rates, and temperatures were studied to assess the descaling efficiency of the descaling machine. The results indicated that under the conditions of a temperature of 30 °C, a flow rate of 0.35 m/s, a voltage of 24 V, and a current of 10 A, the fouling resistance effect of the electrochemical descaling device was optimal. This provides a new perspective for further improving the descaling efficiency of descaling machines and conducting parameter optimization.

1. Introduction

In the cyclic process of industrial circulating cooling water, the concentration of scaling ions increases due to water evaporation. Additionally, as the circulating water temperature rises while passing through heat exchange surfaces, the solubility of scaling ions decreases, leading to the deposition of fouling on heat exchangers and pipeline walls [1]. These deposits reduce the cross-sectional area of the pipes, impeding the flow of circulating water [2]. This not only decreases the heat exchange efficiency of equipment but also causes corrosion of the pipelines, reducing their lifespan and increasing energy consumption and maintenance costs [3,4]. Electrochemical descaling technology is widely applied due to its high efficiency, lack of pollution, and ease of operation [5]. There are multiple factors influencing the efficiency of electrochemical descaling devices, including the choice of electrode materials, the magnitude of current density, the pH value of the electrolyte solution, and parameters such as electrode area and shape. Researchers worldwide have extensively studied electrochemical descaling technology, emphasizing the significant impact of electrode materials on the efficiency and descaling effects of electrochemical reactions [6]. Common anode materials include platinum, metal oxides, titanium-based oxides, and boron-doped diamond (BDD). Frequently used cathode materials include graphite electrodes, precious metal electrodes, carbon-based electrodes, and stainless steel electrodes. Considering economic and accessibility factors, materials such as ruthenium-, iridium-, platinum-, and titanium-based oxides are generally selected as anodes, with cost-effective stainless steel chosen as the cathode electrode [7]. The cathode area is one of the crucial factors affecting electrochemical descaling efficiency. Increasing the cathode area enhances the contact surface area between the electrode and the solution, elevating the concentration of OH⁻ ions on the cathode surface, thereby increasing the pH value of the solution in the cathode region and improving descaling efficiency [8]. Many scholars have found that the pH value of the electrolyte solution plays a vital role in the efficiency of electrochemical descaling and the performance of descaling devices. Variations in pH value alter the solubility of scaling ions, affecting the migration rate and deposition behavior of scaling ions, as well as the reaction rates of the cathode and anode in descaling devices. Numerous experimental results indicate that when the solution pH is too low, it can lead to the corrosion of metal equipment and pipelines, while too high a pH reduces electrode activity. The optimal descaling device efficiency is typically achieved within the pH range of 7–9 [9]. Therefore, adjusting the pH value of the electrolyte solution can control the efficiency of electrochemical descaling devices. Current density is also a key parameter influencing the efficiency of electrochemical descaling devices. Extensive research in this field has shown that current density has a significant impact on reaction rates. Within a certain range, as current density increases, the rate of scaling layer formation on the cathode surface of the electrochemical circulating water descaling device gradually increases until reaching a maximum. Further increases in current density result in a gradual reduction in the scaling layer formation rate [10]. However, there is some disagreement in the research on current density. While many scholars have studied the magnitude of current density and electrode area [11], they often overlook the fact that the voltage and current during descaling device electrolysis are also crucial factors influencing descaling effects [12].

In our research group’s work on electrochemical equipment fouling and descaling technology, we have thoroughly discussed the analysis of electrode area, electrode materials, and the selection of current density [13]. Considering the diverse factors affecting the fouling and descaling efficiency of electrochemical descaling devices during industrial water circulation, this study acknowledges that external environmental conditions during the use of electrochemical descaling devices may impact fouling effects. Combining the aforementioned research findings, experiments were conducted under conditions of solution flow rates of 0 m/s, 0.35 m/s, and 0.7 m/s, temperatures of 26 °C, 28 °C, 30 °C, 32 °C, 34 °C, and 36 °C, and descaling machine voltages of 24 V/10 A, 20 V/7 A, and 16 V/5 A. This research aims to further investigate the impact of changes in solution flow rates, temperatures, descaling machine voltage, and current on fouling effects. Through this study, a re-evaluation of parameter optimization under various working conditions can be conducted to determine the optimal descaling strategy and reduce energy and resource consumption.

2. Electrochemical Descaling Simulation Experiment

2.1. Experimental Setup

Industrial circulating cooling water systems typically consist of devices such as cooling towers, heat exchangers, circulating water pumps, and collection tanks. In order to investigate the effects of water flow velocity, temperature conditions, and electrolysis voltage and current on the efficiency of electrochemical descaling devices, our research group has constructed a simulated industrial circulating cooling water fouling experiment platform. This simulation fouling experiment platform comprises essential components such as a cooling tower, heat exchanger, temperature control device, electrochemical descaling equipment, water pump, and pipelines, aiming to faithfully replicate an industrial circulating cooling water system. The schematic diagram of the simulated industrial circulating cooling water fouling experiment platform is illustrated in Figure 1. The original water and makeup water quality indicators are listed in

Table 1. Water Quality Indicators for Raw Water and Makeup Water.

Water Quality Parameters	pH	Conductivity (μs/cm)	Hardness (ppm)	Cl− Concentration (ppm)	Temperature (°C)
Raw water and supplementary water	6.8 ± 0.2	1500	660	290	26

.

The overall schematic diagram of the simulated industrial circulating cooling water fouling experiment platform is presented in Figure 2.

The electrochemical descaling equipment employed in the experiment is a cage-type descaling machine widely used in practical engineering. The anode electrode of the descaling machine is made of titanium-based ruthenium iridium material, while the cathode utilizes a stainless steel mesh, where scaling ions are deposited through electrolytic reactions. The simulated industrial circulating cooling water fouling experiment platform also incorporates instruments such as a conductivity tester, Cl⁻ concentration tester, pH tester, valves, pressure gauge, flow meter, and chemicals for measurement. The working schematic diagram of the cage-type descaling machine and some of the instruments used are depicted in Figure 3.

The descaling machine has a rated voltage of 24 V and a rated power of 450 W. The connecting wire, with a diameter of 3 cm and a length of 8 m, is connected between the power supply and the descaling machine. The conductivity tester is a model HY-EC 6.0 with a testing range of 0–2000 μS/cm. The Cl⁻ concentration tester utilizes a Qingdao Ruiming chloride ion online water quality detector with a range of 0–9999 ppm. The water pump used is model SGR50-7-18 from Zhejiang Pengye Electromechanical Co., Ltd. (Taizhou, China), with a rated power of 750 W and a flow rate of 7 m³/h. The electromagnetic flowmeter uses the DJLD-DN50 model from Jinhu Smet Instrument Co., Ltd. (Linyi, China), which can control the flow rate within the range of 1–30 m³/h.

Chemical reagents mainly include EDTA solvent, 10% ammonia buffering reagent, 0.1 mol/L sulfuric acid, 0.0282 mol/L silver nitrate solution, phenolphthalein reagent, chrome black T, potassium dichromate, anhydrous calcium chloride, and others.

For solution measurements:

• Solution conductivity is determined using a conductivity meter;
• Chloride ion concentration is measured using the Cl⁻ concentration tester;
• Solution hardness (expressed as CaCO₃) is detected according to GB/T 6909-2018 (methods of analysis for boiler water and cooling water) using the EDTA titration method [14].

A 50.0 mL water sample is taken in a 250 mL conical flask, and 5 mL of ammonia buffering solution and a small amount of chrome black T reagent powder (matchstick head size) or 2–3 drops of chrome black T reagent are added. Titration with ethylenediaminetetraacetic acid (EDTA) is carried out until the solution changes from wine red to a stable bright blue color, indicating the endpoint. The concentration of EDTA solution used for measurement is 0.010 mol/L. Some of the chemicals and reagents used are depicted in Figure 4.

2.2. Experimental Principles

Electrochemical descaling technology, as an effective method for scale removal, is widely applied in practical scenarios, with the cage-type descaling machine being a representative example. The descaling machine operates based on the principles of electrolyzing water, achieving both scale removal and disinfection/algaecide functions simultaneously. A before-and-after comparison of the descaling machine’s usage is illustrated in Figure 5, while a schematic diagram of the operating principles of the descaling machine is presented in Figure 6.

Throughout the process, descaling mainly occurs in the cathode area, while the bactericidal and algal effects are mainly concentrated in the anode area. The main chemical reactions that occur at the cathode are shown in Equations (1) and (2) [15]:

$${\mathrm{O}}_2+2{\mathrm{H}}_2\mathrm{O}+4{\mathrm{e}}^{-}\to 4{\mathrm{OH}}^{-}$$

(1)

The redox reaction of water produces OH⁻ ions, which accompany the entire electrolysis process [16]:

$$2{\mathrm{H}}_2\mathrm{O}+2{\mathrm{e}}^{-}\to {\mathrm{H}}_2\downarrow +2{\mathrm{OH}}^{-}$$

(2)

The hydrogen evolution reaction, during which a large number of bubbles can be seen around the scaling machine, can be considered the main reaction for producing OH⁻ ions [17]

$${\mathrm{CO}}_2+2{\mathrm{OH}}^{-}\to {\mathrm{CO}}_3^{2-}+{\mathrm{H}}_2\mathrm{O}$$

(3)

$${\mathrm{O}}_2+2{\mathrm{H}}_2\mathrm{O}+4{\mathrm{e}}^{-}\to 4{\mathrm{OH}}^{-}$$

(4)

As shown in Equations (3) and (4), the reaction process is accompanied by a small amount of CO₂ reacting with OH⁻ ions, as well as HCO₃⁻ ions moving towards the cathode under mass transfer, reacting with OH⁻ ions to produce CO₃²⁻ ions [18]:

$${\mathrm{Ca}}^{2+}+{\mathrm{CO}}_3^{2-}\to {\mathrm{CaCO}}_3\downarrow$$

(5)

$${\mathrm{Mg}}^{2+}+2{\mathrm{OH}}^{-}\to \mathrm{Mg}{\left(\mathrm{OH}\right)}_2\downarrow$$

(6)

As shown in Equations (5) and (6), Ca²⁺ and Mg²⁺ in water are precipitated in the form of crystals, thereby reducing the hardness of the solution to achieve a scale inhibition effect [19].

The main chemical reactions that occur at the anode are [20,21]:

$${\mathrm{H}}_2\mathrm{O}\to \cdot \mathrm{OH}+{\mathrm{H}}^{+}+{\mathrm{e}}^{-}$$

(7)

$$\cdot \mathrm{O}\mathrm{H}\to 1/2{\mathrm{O}}_2\uparrow +{\mathrm{H}}^{+}+{\mathrm{e}}^{-}$$

(8)

$${\mathrm{O}}_2+2\mathrm{O}{\mathrm{H}}^{-}-2{\mathrm{e}}^{-}\to {\mathrm{O}}_3+{\mathrm{H}}_2\mathrm{O}$$

(9)

The anode area mainly undergoes a water electrolysis reaction, as shown in Equations (7) and (9). By electrolyzing water and partially dissolving oxygen in water, strong oxidizing substances such as ozone (O₃), hydrogen peroxide (H₂O₂), and hydroxyl radicals (·OH) are generated, which can oxidize various components within algae and microbial cells, leading to their death [22]. From Equation (8), it can be seen that the reaction produces a large amount of H⁺, making the cathode region acidic [17].

$$2\mathrm{C}{\mathrm{l}}^{-}\to \mathrm{C}{\mathrm{l}}_2\uparrow +2{\mathrm{e}}^{-}$$

(10)

$${\mathrm{Cl}}_2+{\mathrm{H}}_2\mathrm{O}\to \mathrm{C}{\mathrm{l}}^{-}+{\mathrm{OCl}}^{-}\to \mathrm{RO}\to {\mathrm{H}}_2\mathrm{O}+\mathrm{C}{\mathrm{O}}_2\uparrow$$

(11)

$$\mathrm{R}+\cdot \mathrm{O}\mathrm{H}/{\mathrm{ClO}}^{-}\to \mathrm{RO}\to {\mathrm{H}}_2\mathrm{O}+\mathrm{C}{\mathrm{O}}_2\uparrow$$

(12)

$$\mathrm{bacteria} \mathrm{and} \mathrm{aigae}+ \times \mathrm{OH}/\mathrm{ClO} \to \mathrm{death}$$

(13)

Due to the presence of chloride ions in water, the reaction also produces OCl⁻ (Equations (10) and (11)) with strong oxidation stability [23]. These strong oxidizing substances (such as·OH and OCl⁻) can cause the oxidation of various components in microbial and algal cells, leading to their death (Equation (12)). In this context, R‘‘ represents an organic compound, and R‘O’ represents the residual part of the organic compound (Equation (13)) achieving the effect of sterilization and algae killing [24]. Based on the working principle of the scale remover mentioned above, this article studies the effects of flow rate, temperature, and voltage current on the scale inhibition effect of the scale remover through changes in solution conductivity, hardness, and Cl⁻ concentration in order to seek the best scale inhibition conditions.

2.3. Experimental Procedures

(1)

Initial Setup:

• A predetermined amount of water is injected into the tank, recording the volume as 200 L.
• The water temperature is controlled at 30 °C.
• The initial measurement of conductivity is 756 μS/cm.
• The conductivity is increased to 1500 μS/cm by adding NaCl.
• The descaling machine is activated, recording a current of 10 A and a voltage of 24 V.

(2)

Flow Rate Variation:

• The valve is closed and the values of the hardness, conductivity, and other parameters of the circulating water are measured and recorded during the operation of the scaling machine in still water at intervals of 6.
• The valve is opened, adjusting the flow rates to 0.35 m/s and 0.75 m/s, respectively.
• Changes in the above water quality parameters are monitored to investigate the effect of flow rate on fouling efficiency.

(3)

Voltage and Current Variation:

• A solution volume of 200 L is maintained, at a temperature of 30 °C, conductivity of 1500 μS/cm, and flow rate of 0.35 m/s.
• Experiments are conducted with different voltage and current settings for the descaling machine: 24 V/10 A, 20 V/7 A, and 16 V/5 A.
• Changes in water quality parameters are recorded to explore the impact of descaling machine voltage and current on fouling effects.

(4)

Temperature Variation:

• A solution flow rate of 0.35 m/s, descaling machine voltage of 24 V, and current of 10 A are maintained.
• The temperature control device is used to set the circulating water temperatures to 26 °C, 28 °C, 30 °C, 32 °C, 34 °C, and 36 °C.
• The influence of temperature on the descaling machine’s fouling efficiency is investigated by recording changes in water quality parameters.

3. Experimental Results and Analysis

There are several factors influencing the operation of the descaling machine, with significant impacts from the solution flow rate, temperature, and voltage/current of the descaling machine. This article primarily explores the effects of changes in temperature, flow rate, and descaling machine voltage/current on the descaling machine’s efficiency.

3.1. Flow Rate

In this experiment, with an initial solution conductivity of 1500 μS/cm, hardness of 660 ppm, Cl⁻ concentration of 290 ppm, water volume of 100 L, temperature of 30 °C, and the descaling machine operating at 24 V/10 A, the flow rates were varied at 0 m/s, 0.35 m/s, and 0.75 m/s. The conductivity, hardness, and Cl⁻ concentration of the solution were recorded every 6 h to observe the changes in the descaling machine’s operation time and to understand the impact of flow rate on the fouling and descaling effects.

3.1.1. Impact of Flow Rate on Conductivity

Conductivity is a physical quantity that measures the solution’s electrical conductivity, reflecting changes in the total ion concentration or dissolved salt content in the water. The variation in solution conductivity with the descaling machine’s working time is shown in Figure 7a. It can be observed that the solution’s conductivity generally increases initially and then decreases with the descaling machine’s operation time, with some fluctuations. This phenomenon is attributed to the rapid generation of ions at the anode and cathode when the descaling machine starts working, leading to an increase in solution conductivity. As the reaction time increases, scaling ions precipitate at the cathode, resulting in a decrease in solution conductivity. The flow rate accelerates the movement of ions, amplifying the decreasing trend in conductivity, making the fouling resistance more apparent. However, it is important to note that a higher flow rate does not necessarily guarantee better fouling resistance.

3.1.2. Impact of Flow Rate on Hardness

Water hardness refers to the amount of soluble calcium ions, magnesium ions, and other multivalent metal ions in water. Hardness is usually measured in units of mg/L and ppm. A decrease in solution hardness indicates a reduction in the content of calcium and magnesium ions, which precipitate in the form of scale. Therefore, hardness can be considered a factor in evaluating the efficiency of the descaling machine. Figure 7b illustrates the impact of flow rate on solution hardness as the descaling machine operates over time.

Flow rate does not have a direct impact on solution hardness, but it can increase the movement speed of ions in the solution, thereby increasing the rate at which scaling ions combine and precipitate in crystalline form. Flow rate does not significantly alter the decreasing trend of solution hardness, but it does contribute to a smoother decline. The relationship between solution flow rate and hardness is not linear.

3.1.3. Impact of Flow Rate on Cl⁻ Concentration

Since Cl⁻ does not undergo precipitation, the concentration ratio of Cl⁻ in circulating water to Cl⁻ in the original water can be calculated to represent the concentration multiplier in circulating cooling water. Chloride ions have a certain corrosiveness, and prolonged high concentrations of Cl⁻ may corrode water treatment equipment such as pipes, valves, and pumps. Reducing Cl⁻ concentration can extend the equipment’s lifespan and reduce maintenance and replacement costs. As water evaporates during the industrial circulating cooling water process, the solubility of the solution decreases, leading to the precipitation of some soluble salts, which affects descaling efficiency.

The impact of flow rate on Cl⁻ concentration in water is shown in Figure 7c. The trend of changes in Cl⁻ concentration in the solution with flow rate is roughly the same, with an initial increase followed by a decrease. The reason why Cl⁻ in water first rises and then falls during electrolysis is due to the reaction of chlorine gas precipitation and re-dissolution that occurs during the electrolysis process. During the operation of the scaling machine, when current passes through water, water molecules undergo electrolysis, producing hydrogen and oxygen gas.

3.2. Voltage and Current

Changes in the operating voltage and current of the descaling machine can alter the electrolysis rate of the solution and its solubility, affecting the precipitation of scaling ions and consequently influencing the fouling resistance. Changes in voltage and current can also impact the solution’s temperature; therefore, a temperature control device is used to maintain a constant solution temperature of 30 °C. In this experiment, with a water volume of 100 L, solution flow rate of 0.35 m/s, initial conductivity of 1500 μS/cm, hardness of 660 ppm, and Cl⁻ concentration of 290 ppm, the voltage of the descaling machine is varied at 24 V with a current of 7 A, 20 V with a current of 6 A, and 16 V with a current of 5 A. The conductivity, hardness, and Cl⁻ concentration of the solution are recorded every 6 h to observe changes in the descaling machine’s operation time and to understand the impact of descaling machine voltage and current on fouling and descaling effects.

3.2.1. Impact of Voltage and Current on Conductivity

Changes in the voltage and current of the descaling machine can affect the solution’s ion concentration and electrochemical equilibrium, as increased voltage and current enhance the electrolysis rate of ions, thereby increasing the solution’s conductivity. The experimental results depicting the influence of different voltage and current settings on conductivity are shown in Figure 7d.

From the graph, it can be observed that increasing voltage and current will raise the ion concentration in the solution. This is because the conduction of current requires the presence of charged particles, and the increase in voltage and current can promote the movement and diffusion of charged particles, thereby enhancing the solution’s conductivity. However, as the conductivity reaches a certain level, it is influenced by the ion concentration in the solution. When the ion concentration in the solution is already high, even with an increase in voltage and current, the release of additional ions will be limited. Therefore, the extent to which conductivity can be increased is limited. When the concentration of scaling ions is excessively high, they will precipitate at the cathode, causing a decrease in solution conductivity, ultimately stabilizing to achieve fouling resistance.

3.2.2. Impact of Voltage and Current on Solution Hardness

The influence of descaling machine voltage, current, and solution temperature on solution hardness primarily manifests in the solubility of the solution. Changes in the voltage and current of the descaling machine may affect the precipitation and dissolution rates of ions such as calcium and magnesium. Higher voltage and current can promote the formation of precipitates of dissolved metal ions, reducing solution hardness. However, the impact of voltage and current on solution hardness is not significant. The experimental results regarding the impact of voltage and current on solution hardness are shown in Figure 8a, indicating that the variation in hardness is fluctuating, but there is an overall decreasing trend. Compared to the initial solution hardness, the effect of higher voltage and current on reducing hardness is more pronounced.

3.2.3. Impact of Voltage and Current on Solution Cl⁻ Concentration

In the descaling machine electrolysis process, changes in voltage and current are primarily aimed at removing scale deposits. However, this process may affect the concentration of chloride ions. During the electrolysis process, the anode and cathode generate a potential difference under the influence of the applied electric field. When a solution containing scale passes through the electrolytic cell, chloride ions on the anode move towards it, and an oxidation reaction occurs, producing chlorine gas. This process aims to remove chloride ions from the water, and this phenomenon becomes more pronounced with increased voltage and current.

As shown in Figure 8b, the impact of descaling machine voltage and current on the Cl⁻ concentration in the solution exhibits an initial increase followed by a gradual decrease. This phenomenon may be attributed to the electrolysis process. When an electric current passes through the NaCl electrolyte solution, NaCl decomposes into Na⁺ ions and Cl⁻ ions, leading to a rapid increase in Cl⁻ concentration. However, with an increase in electrolysis time, oxidation of Cl⁻ occurs in the anode region, converting Cl⁻ into Cl₂, which is released. Since Cl₂ is denser than air and soluble in water, it generates OCl⁻, but a small amount of Cl₂ may overflow, resulting in a slow decline in solution Cl⁻ concentration. It can be observed that at a descaling machine voltage of 24 V and a current of 10 A, the Cl⁻ concentration shows the smallest variation with the most pronounced decreasing trend. Therefore, under these conditions, the electrochemical descaling equipment exhibits the most effective antifouling and corrosion resistance.

3.3. Temperature

The influence of temperature on electrochemical descaling and scale removal is manifested in various aspects. Firstly, an increase in temperature enhances the activity of ions in the solution, accelerating their movement and thereby increasing the solution’s conductivity. Secondly, temperature has a certain impact on the chemical equations involved in electrochemical descaling and scale removal technology. Specifically, an increase in temperature speeds up the reaction rate of the solution. Additionally, temperature affects the solubility of the solution and alters the concentration of scale ions, thereby influencing the descaling effect.

In this experiment, the descaling machine operates at a voltage of 24 V, a current of 10 A, and a flow rate of 0.35 m/s. The initial conductivity of the solution is 1500 μS/cm, the hardness is 660 ppm, the chloride ion concentration is 290 ppm, and the volume of water is 100 L. Since the descaling machine generates heat during operation, a temperature control device is used to maintain a constant temperature. Considering that most industrial circulating water flows under normal temperature conditions, the experiment utilizes six sets of data at temperatures of 26 °C, 28 °C, 30 °C, 32 °C, 34 °C, and 36 °C to explore the influence of temperature on the descaling efficiency of the machine. As the temperature increases, the solubility of the solution increases, leading to an increase in ion concentration. The dynamic energy of ions in the solution increases, resulting in faster ion movement, higher ionization rates, and an overall increase in the solution’s conductivity. Temperature changes also affect the solubility of ions such as calcium and magnesium. Generally, with an increase in temperature, solubility and hardness increase correspondingly. The influence of temperature on solution conductivity and hardness is shown in Figure 8c,d.

According to the graphs, temperature significantly impacts the conductivity and hardness of the solution. As temperature rises, the magnitude of the change in solution conductivity increases. Moreover, the impact of temperature on the hardness of the solution is mainly reflected in the solubility of calcium ions and magnesium ions. When the temperature is excessively high, an increase in solubility leads to more calcium and magnesium ions dissolving in water, resulting in an increase in solution hardness.

In summary, at a temperature of 30 °C, the solution exhibits the greatest decrease in both conductivity and hardness, with the most pronounced decreasing trend. This observation indicates that, under these temperature conditions, the electrochemical descaling equipment achieves optimal scale removal efficiency.

4. Conclusions and Outlook

This paper constructed an experimental platform for the descaling device to analyze factors influencing the descaling efficiency. The impact of three factors—flow rate, voltage, current, and temperature—on descaling efficiency was expressed through the changes in solution conductivity, hardness, and Cl⁻ concentration over time. The main conclusions drawn are as follows:

(1)

The descaling machine demonstrates effective scale inhibition. Through the electrolysis of water and the generation of a large number of OH⁻ ions at the cathode, a high-alkalinity zone is formed, causing metal ions to rapidly precipitate from the water and adhere to the cathode surface, thereby reducing water conductivity and hardness and achieving scale inhibition. Additionally, the strongly oxidative substances generated at the anode, such as ozone (O₃), hydrogen peroxide (H₂O₂), hydroxyl radicals (·OH), and the oxidation-stable OCl⁻, exhibit certain sterilization and algae-killing effects.

(2)

In the experiments examining the influence of different flow rates, temperatures, voltages, and currents on descaling efficiency, it is found that at a flow rate of 0.35 m/s, a temperature of 30 °C, and a descaling machine voltage of 24 V and current of 10 A, the conductivity, hardness, and Cl⁻ concentration are the lowest. This indicates that under these conditions, the best descaling effect is achieved.

The current data have certain limitations. To better understand the impact of external environmental factors on electrochemical descaling efficiency and draw more accurate conclusions, future work should involve more orthogonal experiments and data optimization. By introducing additional variables and factors, a more comprehensive exploration of the relationships between data can be conducted, thereby enhancing the reliability and effectiveness of the research. This will further contribute to the application of electrochemical descaling technology in engineering practice, addressing real issues in circulating cooling water systems.