Process for treating aqueous solution to inhibit incrustation by using pulsed magnetic field

Abstract

The invention provides a process for inhibiting scale by treating an aqueous solution with a pulsed magnetic field. The process comprises the following steps: treating the aqueous solution with the pulsed magnetic field for 20-30 minutes; the concentration of calcium ions in the aqueous solution is 0.5-20 mmol / L; the frequency of the pulsed magnetic field is 1-4 kHz; the number of ampere turns of the pulsed magnetic field is 80-300 NI; the duty ratio of the pulsed magnetic field is 5%-50%; according to the process, the frequency, the ampere turns and the duty ratio of the pulsed magnetic field are selectively and accurately regulated and controlled, the calcium ion aqueous solutions with different concentrations are optimized, efficient inhibition of calcium carbonate scale is achieved, and the process for treating the aqueous solutions through the pulsed magnetic field to inhibit the scale is suitable for low-concentration calcium ion solutions and also suitable for low-concentration calcium ion solutions. And the scale inhibitor can also show a good scale inhibition effect in a high-concentration calcium ion environment, so that the problem that the effect is unstable when a traditional descaling method is used for treating aqueous solutions with different concentrations is solved.

Description

Technical Field

[0001] The invention relates to a scale inhibition and descaling treatment technology, in particular to a process for inhibiting scale by treating an aqueous solution with a pulse magnetic field. Background Art

[0002] Scale refers to solid matter deposited on the tube wall of heat exchange equipment in contact with water. It generally exists in the aqueous solution in the form of a mixture of impurities. Scaling refers to the process in which the tube wall through which water flows changes from a clean surface to being attached by solid matter, and gradually changes from a thin layer of soft scale to hard scale over time.

[0003] The main component of scale is calcium carbonate (CaCO3). Scale is deposited on the tube wall of heat exchange equipment. The main hazards caused by scale are reducing the performance of the heat exchange surface, increasing flow resistance, blocking pipelines and affecting the service life of equipment. In the industrial processing process, more than 90% of heat exchangers have serious scaling. According to statistics, when the thickness of the calcium carbonate scale layer is 1.5mm, the energy consumption will increase by 10%-20%, and when the thickness of the calcium carbonate scale layer is 2.5mm, the efficiency of the heat transfer equipment will be reduced by 95%. In the industrial processing process in the United States, the economic losses caused by the scaling of heat exchange equipment are converted into RMB of about 10 billion yuan. Studies have shown that if the thickness of the scale exceeds 1mm, 3-5% of the fuel will be wasted. Therefore, the scaling problem of the tube wall of heat exchange equipment has received widespread attention from researchers and scholars in various countries.

[0004] Based on the above problems, the research on water descaling has become an issue that needs to be solved urgently in the process of industrialization. The existing descaling methods include chemical methods, membrane treatment technology, mechanical cleaning technology, physical methods (high-voltage electrostatic water treatment technology, ultrasonic technology) and other technical solutions.

[0005] However, chemical scale prevention is expensive, and incorrect use methods may harm the workers' health. At the same time, the right medicine is needed. Different types of scale use different chemical means. If used improperly, not only will the expected effect not be achieved, but it may also affect the physical and chemical properties of the original aqueous solution and even cause secondary pollution to the environment; membrane treatment technology has a low oil removal rate and the membrane is easily contaminated; mechanical cleaning technology has a large economic loss rate, high labor intensity, low scale removal efficiency, and requires a lot of manpower; high-voltage electrostatic water treatment technology cannot meet people's high standards for scale prevention due to the complexity of the water body itself and the influence of the environment. At the same time, high-voltage electrostatic water treatment equipment consumes a lot of electricity during operation. If it is not operated properly, it will endanger the health of the workers; ultrasonic technology is expensive and inconvenient to maintain and detect. Since the use conditions of ultrasonic technology are greatly affected by the environment, its scale prevention and removal are unstable.

[0006] Based on this, it is particularly urgent to study the mechanism and technology of pulsed magnetic field scale inhibition of calcium carbonate, a process that uses pulsed magnetic field to treat aqueous solution to inhibit scale. Summary of the invention

[0007] In order to solve the above technical problems, the present invention provides a process for inhibiting scale by treating an aqueous solution with a pulsed magnetic field, wherein the aqueous solution is treated with a pulsed magnetic field for 20-30 minutes; The concentration of calcium ions in the aqueous solution is 0.5-20mmol / L; The frequency of the pulsed magnetic field is 1-4kHz; The ampere-turns of the pulsed magnetic field are 80-300 NI; The duty cycle of the pulsed magnetic field is 5%-50%.

[0008] Preferably, the concentration of calcium ions in the aqueous solution is greater than or equal to 0.5 mmol / L and less than 8 mmol / L; The frequency of the pulsed magnetic field is greater than or equal to 1 kHz and less than 2 kHz; The ampere-turns of the pulsed magnetic field is greater than or equal to 80NI and less than 165NI; The duty cycle of the pulse magnetic field is greater than or equal to 5% and less than 25%.

[0009] Preferably, the concentration of calcium ions in the aqueous solution is 2 mmol / L or 5 mmol / L; The frequency of the pulsed magnetic field is 1.25kHz; The ampere-turns of the pulsed magnetic field is 160NI; The duty cycle of the pulsed magnetic field is 20%.

[0010] Preferably, the concentration of calcium ions in the aqueous solution is greater than or equal to 8 mmol / L and less than 12 mmol / L; The frequency of the pulsed magnetic field is greater than or equal to 2 kHz and less than 3 kHz; The ampere-turns of the pulsed magnetic field is greater than or equal to 165 NI and less than 220 NI; The duty cycle of the pulse magnetic field is greater than or equal to 25% and less than 35%.

[0011] Preferably, the concentration of calcium ions in the aqueous solution is greater than or equal to 12 mmol / L and less than 20 mmol / L; The frequency of the pulsed magnetic field is greater than or equal to 3 kHz and less than 4 kHz; The ampere-turns of the pulse magnetic field is greater than or equal to 220NI and less than 300NI; The duty cycle of the pulse magnetic field is greater than or equal to 35% and less than 50%.

[0012] Preferably, the scale is calcium carbonate.

[0013] Preferably, a pulse magnetic field scale inhibition device is used to perform pulse magnetic field treatment on the aqueous solution.

[0014] Preferably, the pulse magnetic field scale inhibition device includes a pH meter, a copper sheet, an electromagnetic coil, a liquid container, and a pulse power supply box; the positive and negative poles of the power supply of the pulse power supply box are electrically connected to the inlet and outlet at both ends of the electromagnetic coil; the electromagnetic coil is wound around the outer wall of the liquid container, and the liquid container contains an aqueous solution to be treated. The pH meter is movably plugged into the aqueous solution to be treated to determine the pH value of the aqueous solution to be treated; the copper sheet is movably arranged at the bottom of the liquid container. Calcium carbonate is not easy to dissolve, but calcium carbonate easily adsorbs copper on the surface. The copper sheet is used to assist in the detection and measurement of calcium carbonate.

[0015] Preferably, the electromagnetic coil is a coil wound by enameled wire.

[0016] Preferably, the electromagnetic coil is a copper coil or an iron core copper coil.

[0017] In the present invention, the positive and negative electrodes of the pulse magnetic field scale prevention device are connected to the inlet and outlet of the coil, and the electromagnetic energy generated by the pulse power box is transmitted to the solution in the liquid container through the electromagnetic coil. The pulse magnetic field scale prevention device uses the pulse magnetic field to transfer energy. The scale prevention principle of the pulse magnetic field is as follows: Figure 1 As shown in the figure, 6 represents bicarbonate ions, 7 represents calcium ions, 8 represents calcium carbonate crystals formed by the combination of bicarbonate ions and calcium ions, and 9 represents a pulse power supply box. The pulse magnetic field anti-scaling device generates a pulse electromagnetic square wave signal, which reacts with the scale-forming ions in the solution through the pulse electromagnetic square wave signal, thereby changing its motion state to achieve the anti-scaling effect.

[0018] In the present invention, the pulse signal generated by the pulse magnetic field scale inhibition device is amplified and output to the electromagnetic coil wound on the beaker. This phenomenon can be expressed by Faraday's law of electromagnetic induction. At the same time, under the action of the induced electric field, the physical and chemical properties of ions and molecules in the water will change, so that the generated calcium carbonate precipitate will undergo crystal nucleation or crystal growth, thereby achieving a scale inhibition effect. The expression is as follows: Where: E -Induced electric field vector, V; s - Line vector along the circumference, m; B -Magnetic field strength vector, T; A - Cross-sectional area of ​​the pipe, m 2 .

[0019] The mechanism of action of the present invention for inhibiting scale is as follows: 1. Effect of pulsed magnetic field on water molecules Under the action of the pulsed magnetic field, the aqueous solution will absorb the energy generated by the pulsed magnetic field, causing changes in the hydrated ions in the aqueous solution, thereby affecting the clusters in the water molecules, and finally causing changes in the precipitation process of calcium carbonate crystals, as follows: (1) Molecular clusters in aqueous solutions usually exist in the form of large water molecules ((H2O)n, n=2, 3, 4). This form of water molecule clusters is similar to Ca 2+ The affinity of Ca 2+ The solubility in aqueous solution is relatively low, making it easy for calcium carbonate crystals to precipitate, but hard scale that adheres to the pipe wall and is difficult to remove is generated. After being treated by the technical solution of the present invention, the hydrogen bonds in the water molecules will be broken under the action of the pulsed magnetic field, thereby decomposing the large water molecules ((H2O)n, n=2, 3, 4) into small water molecule clusters, which interact with ions to finally generate a relatively stable compound {[Ca(H2O)6]·20H2O} 2+ ,like Figure 2 As shown, this compound will prevent the reaction between calcium ions and carbonate ions, achieving the effect of scale inhibition; (2) As the number of small water molecules increases, the water molecules move more freely, the viscosity of the aqueous solution decreases, the solubility increases, and the permeability increases, so that the molecules in the aqueous solution gradually enter the gaps in the old scale and disintegrate it, thereby causing the scale-forming ions in the solution to continuously precipitate and not easily adhere to the surface of the pipe wall; (3) When positive ions and negative ions in an aqueous solution move, the opposite movement of the positive and negative ions will break the hydrogen bonds in the water, thereby changing the structure of the water molecules, accelerating the decomposition of large water molecules into small water molecules. The change in the structure of water molecules will also change the physical and chemical properties of the aqueous solution, such as conductivity and viscosity. The change in these properties also helps to reduce the formation and adhesion of scale, thereby synergistically promoting the scale inhibition ability of the technical solution of the present invention, and the scale removal effect is more significant.

[0020] 2. Effect of pulsed magnetic field on the crystal structure of calcium carbonate The Ca2+ and CO3²⁻ of calcium carbonate in water usually exist in the form of hydrated ions, and the charges of the two are opposite. When a pulse signal is applied to the water, the aqueous solution will be affected by the Lorentz force and absorb the energy generated by the pulse magnetic field, which affects the interaction between ions and water molecules in the aqueous solution, as well as the interaction between ions and calcium carbonate crystals, thereby changing the structure of the calcium carbonate crystals in the solution, as follows: (1) When a pulse signal is applied to water, the scale-forming ions in the aqueous solution will move towards each other due to the Lorentz force. Under the action of the pulse magnetic field, positively charged ions (such as Ca²⁺) and negatively charged ions (such as carbonate ions) will be subjected to different forces and move in different directions, thereby greatly increasing the probability and efficiency of effective collisions between ions, making it easier for them to form new crystal nuclei, such as Figure 3 As shown in the figure, 10 represents ions with positive charge, 11 represents ions with negative charge, and 12 represents ion clusters formed by the final combination of ions with positive charge and ions with negative charge; under the action of the Lorentz force and the pulsed magnetic field, the ions in the aqueous solution will be surrounded by more small water molecules, and hydrated ions are thus produced. Because the hydrated ions are tightly surrounded by water molecules, it is difficult for them to move freely. Their characteristic is that they are difficult to dissolve. This hydration also changes the precipitation conditions of calcium carbonate crystals.

[0021] (2) The pulsed magnetic field not only affects the movement of ions and the formation of hydrated ions, but also changes the structure of calcium carbonate crystals. Usually, calcium carbonate crystals will crystallize in the form of calcite or aragonite. Under the action of the pulsed magnetic field, the precipitated calcium carbonate crystals are more inclined to form a calcite structure. The crystals of this structure have a lower viscosity and are not easy to adhere to the wall of the heat exchange equipment. In contrast, the calcium carbonate with an aragonite structure has a higher viscosity and is easy to form scale that is difficult to remove.

[0022] (3) According to the phase change principle, the saturation required for the precipitation of calcium carbonate crystals will be reduced with the appearance of new crystal nuclei. The pulsed magnetic field promotes the formation of new crystal nuclei by increasing the collision probability and efficiency between ions, thereby reducing the saturation of calcium carbonate crystal precipitation. At the same time, when calcium carbonate crystals precipitate, the required temperature is also lower. This means that under the same conditions, a large number of tiny crystal particles are more likely to form in the aqueous solution after pulsed magnetic field treatment, reducing the formation of scale and achieving the effect of scale inhibition.

[0023] (4) After being treated with a pulsed magnetic field, the movement resistance between the crystal particles in the dipole group becomes larger. This increase in resistance makes it more difficult for the tiny crystal particles to move in the solution, thereby reducing their chances of contact with the wall of the heat exchange equipment. Therefore, the amount of calcium carbonate scale deposited on the wall will also be reduced accordingly.

[0024] (5) Pulsed magnetic field treatment also leads to an increase in the amount of soft scale generated by crystallization. These soft scales are small in size, large in number, irregular in shape, and not easy to adhere to the wall. In contrast, hard scales are usually large in size, small in number, regular in shape, and easy to adhere to the wall to form scale that is difficult to remove. Therefore, the increase in soft scale also helps to reduce scale deposition on the wall of heat exchange equipment.

[0025] Compared with the prior art, the present invention has the following beneficial effects: 1. It was found in the study that the scale inhibition effect of the pulsed magnetic field water treatment device was different with different parameters. This was mainly related to the uncertainty of the aqueous solution itself and the environment. Setting specific parameters according to a certain experiment might not achieve the expected effect. Therefore, the present invention uses a large number of experiments and theoretical analysis to understand its mechanism of action, selectively and accurately adjusts the frequency, ampere-turns and duty cycle of the pulsed magnetic field, optimizes the treatment of aqueous solutions of calcium ions with different concentrations, and achieves efficient inhibition of calcium carbonate scale. The process of inhibiting scale by treating aqueous solutions with pulsed magnetic fields provided by the present invention is not only suitable for low-concentration calcium ion solutions, but also can show good scale inhibition effect in high-concentration calcium ion environments, thereby solving the problem of unstable effect of traditional descaling methods when treating aqueous solutions of different concentrations.

[0026] 2. Compared with traditional descaling methods such as chemical methods, membrane treatment technology, and mechanical cleaning technology, the pulse magnetic field treatment technology used in the present invention does not require the addition of any chemical agents, avoiding secondary pollution and negative impacts on the environment. At the same time, the pulse magnetic field treatment process does not involve dangerous operations such as high temperature and high pressure, thereby ensuring the safety of the staff.

[0027] 3. The pulse magnetic field treatment device provided by the present invention has a simple structure and low operation and maintenance costs. In addition, due to the low energy consumption during the pulse magnetic field treatment process, compared with high-voltage electrostatic water treatment technology and ultrasonic technology, the present invention shows obvious advantages in energy saving.

[0028] 4. The present invention is not only applicable to heat exchange equipment in industrial processing, but can also be widely used in various occasions where scale formation needs to be prevented, such as household water, industrial cooling water, boiler water, etc., and has broad market application prospects.

[0029] 5. By adopting the technical solution of the present invention, under the action of the pulsed magnetic field, the aqueous solution will absorb the energy generated by the pulsed magnetic field, causing the hydrated ions in the aqueous solution to change, thereby affecting the clusters in the water molecules, and finally causing the precipitation process of the calcium carbonate crystals to change, as follows: (1) Molecular clusters in aqueous solutions usually exist in the form of large water molecules ((H2O)n, n=2, 3, 4). This form of water molecule clusters is similar to Ca 2+ The affinity of Ca 2+The solubility in aqueous solution is relatively low, making it easy for calcium carbonate crystals to precipitate, but hard scale that adheres to the pipe wall and is difficult to remove is generated. After being treated by the technical solution of the present invention, the hydrogen bonds in the water molecules will be broken under the action of the pulsed magnetic field, thereby decomposing the large water molecules ((H2O)n, n=2, 3, 4) into small water molecule clusters, which interact with ions to finally generate a relatively stable compound {[Ca(H2O)6]·20H2O} 2+ ,like Figure 2 As shown, this compound will prevent the reaction between calcium ions and carbonate ions, achieving the effect of scale inhibition; (2) As the number of small water molecules increases, the water molecules move more freely, the viscosity of the aqueous solution decreases, the solubility increases, and the permeability increases, so that the molecules in the aqueous solution gradually enter the gaps in the old scale and disintegrate it, thereby causing the scale-forming ions in the solution to continuously precipitate and not easily adhere to the surface of the pipe wall; (3) When positive ions and negative ions in an aqueous solution move, the opposite movement of the positive and negative ions will break the hydrogen bonds in the water, thereby changing the structure of the water molecules, accelerating the decomposition of large water molecules into small water molecules. The change in the structure of water molecules will also change the physical and chemical properties of the aqueous solution, such as conductivity and viscosity. The change in these properties also helps to reduce the formation and adhesion of scale, thereby synergistically promoting the scale inhibition ability of the technical solution of the present invention, and the scale removal effect is more significant.

[0030] 6. Ca in water 2+ and CO3²⁻ etc. usually exist in the form of hydrated ions, and the charges of the two are opposite. When a pulse signal is applied to water using the technical direction of the present invention, the aqueous solution will be affected by the Lorentz force to absorb the energy generated by the pulse magnetic field, and affect the interaction between ions and water molecules in the aqueous solution, as well as the interaction between ions and ions and calcium carbonate crystals, thereby changing the structure of the calcium carbonate crystals in the solution, as follows: (1) When a pulse signal is applied to water, the scale-forming ions in the aqueous solution will move towards each other due to the Lorentz force. Under the action of the pulse magnetic field, positively charged ions (such as Ca²⁺) and negatively charged ions (such as carbonate ions) will be subjected to different forces and move in different directions, thereby greatly increasing the probability and efficiency of effective collisions between ions, making it easier for them to form new crystal nuclei, such as Figure 3 As shown; under the action of the Lorentz force and the pulsed magnetic field, the ions in the aqueous solution will be surrounded by more small water molecules, and hydrated ions are thus produced. Because the hydrated ions are tightly surrounded by water molecules, it is difficult for them to move freely. Their characteristic is that they are difficult to dissolve. This hydration also changes the precipitation conditions of calcium carbonate crystals.

[0031] (2) The pulsed magnetic field not only affects the movement of ions and the formation of hydrated ions, but also changes the structure of calcium carbonate crystals. Usually, calcium carbonate crystals will crystallize in the form of calcite or aragonite. Under the action of the pulsed magnetic field, the precipitated calcium carbonate crystals are more inclined to form a calcite structure. The crystals of this structure have a lower viscosity and are not easy to adhere to the wall of the heat exchange equipment. In contrast, the calcium carbonate with an aragonite structure has a higher viscosity and is easy to form scale that is difficult to remove.

[0032] (3) According to the phase change principle, the saturation required for the precipitation of calcium carbonate crystals will be reduced with the appearance of new crystal nuclei. The pulsed magnetic field promotes the formation of new crystal nuclei by increasing the collision probability and efficiency between ions, thereby reducing the saturation of calcium carbonate crystal precipitation. At the same time, when calcium carbonate crystals precipitate, the required temperature is also lower. This means that under the same conditions, a large number of tiny crystal particles are more likely to form in the aqueous solution after pulsed magnetic field treatment, reducing the formation of scale and achieving the effect of scale inhibition.

[0033] (4) After being treated with a pulsed magnetic field, the movement resistance between the crystal particles in the dipole group becomes larger. This increase in resistance makes it more difficult for the tiny crystal particles to move in the solution, thereby reducing their chances of contact with the wall of the heat exchange equipment. Therefore, the amount of calcium carbonate scale deposited on the wall will also be reduced accordingly.

[0034] (5) Pulsed magnetic field treatment also leads to an increase in the amount of soft scale generated by crystallization. These soft scales are small in size, large in number, irregular in shape, and not easy to adhere to the wall. In contrast, hard scales are usually large in size, small in number, regular in shape, and easy to adhere to the wall to form scale that is difficult to remove. Therefore, the increase in soft scale also helps to reduce scale deposition on the wall of heat exchange equipment.

[0035] 7. It was found during the experiment that although the pulsed magnetic field would affect the amount of CO2 dissolved, the experimental results showed that it had little effect on the acidity and alkalinity of the calcium carbonate solution. This indicates that the present invention will not significantly change the pH value of the aqueous solution while preventing scale, thereby maintaining the original properties of the aqueous solution and avoiding other problems caused by changes in pH value.

[0036] 8. During the experiment, it was found that after being treated with a pulsed magnetic field, the initial decomposition temperature of calcium carbonate crystals would drop by about 40°C, and by up to 46°C. This shows that the pulsed magnetic field not only affects the structure and morphology of calcium carbonate crystals, but also changes their thermodynamic properties. This change helps promote the decomposition of calcium carbonate crystals at a lower temperature, further reducing the formation of scale. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a schematic diagram of the pulse magnetic field scale inhibition principle in the present invention; Figure 2This is a schematic diagram of the scale inhibition principle of water molecules; Figure 3 It is a schematic diagram of the effect of the pulsed magnetic field of the present invention on charged ions in a solution; Figure 4 A schematic diagram of a pulse magnetic field scale inhibition device provided by the present invention; Figure 5 The crystal morphology of calcium carbonate in Experiment 4 is compared. 5a is the crystal morphology of the acid calcium obtained from sample a, 5b is the crystal morphology of the acid calcium obtained from sample b, 5c is the crystal morphology of the acid calcium obtained from sample c, 5d is the crystal morphology of the acid calcium obtained from sample d, 5e is the crystal morphology of the acid calcium obtained from sample e, and 5f is the crystal morphology of the acid calcium obtained from sample f; Figure 6 6a is a comparison of the crystal morphology of calcium carbonate in Experiment 5, 6b is a crystal morphology of the acid calcium obtained from sample a, 6c is a crystal morphology of the acid calcium obtained from sample b, 6d is a crystal morphology of the acid calcium obtained from sample d, and 6e is a crystal morphology of the acid calcium obtained from sample e; Figure 7 7a is a comparison of the crystal morphology of calcium carbonate in Experiment 6, 7b is a crystal morphology of the acid calcium obtained from sample a, 7c is a crystal morphology of the acid calcium obtained from sample c, 7d is a crystal morphology of the acid calcium obtained from sample d, and 7e is a crystal morphology of the acid calcium obtained from sample e; Figure 8 This is a comparison of the crystal morphology of calcium carbonate in Experiment 7. 8a is the crystal morphology of the 2mmol / l untreated group, 8b is the crystal morphology of the 2mmol / l treated group, 8c is the crystal morphology of the 3mmol / l untreated group, d is the crystal morphology of the 3mmol / l treated group, 8e is the crystal morphology of the 4mmol / l untreated group, f is the crystal morphology of the 4mmol / l treated group, 8g is the crystal morphology of the 5mmol / l untreated group, and 8h is the crystal morphology of the 4mmol / l treated group.

[0038] In the figure, pH meter-1, copper sheet-2, electromagnetic coil-3, liquid container-4, pulse power supply box-5, bicarbonate ions-6, calcium ions-7, calcium carbonate crystals-8, pulse power supply box-9, positively charged ions-10, negatively charged ions-11, and ion clusters-12. DETAILED DESCRIPTION

[0039] Example 1 like Figure 4As shown, a pulse magnetic field scale inhibition device includes a pH meter 1, a copper sheet 2, an electromagnetic coil 3, a liquid container 4, and a pulse power supply box 5; the positive and negative poles of the power supply of the pulse power supply box 5 are electrically connected to the inlet and outlet at both ends of the electromagnetic coil 3; the electromagnetic coil 3 is wound around the outer wall of the liquid container 4, and the liquid container 4 contains an aqueous solution to be treated, and the pH meter 1 is movably plugged into the aqueous solution to be treated for measuring the pH value of the aqueous solution to be treated; the copper sheet 2 is movably arranged at the bottom of the liquid container 4.

[0040] Moreover, the electromagnetic coil 3 is a coil wound with enameled wire.

[0041] Moreover, the electromagnetic coil 3 is a copper coil.

[0042] Example 2 Different from the first embodiment, the electromagnetic coil 3 is an iron core copper coil.

[0043] Example 3 A process for inhibiting scale by treating an aqueous solution with a pulsed magnetic field, wherein the aqueous solution is treated with a pulsed magnetic field 20; The concentration of calcium ions in the aqueous solution is greater than or equal to 0.5 mmol / L and less than 8 mmol / L; The frequency of the pulsed magnetic field is greater than or equal to 1 kHz and less than 2 kHz; The ampere-turns of the pulsed magnetic field is greater than or equal to 80NI and less than 165NI; The duty cycle of the pulse magnetic field is greater than or equal to 5% and less than 25%.

[0044] Moreover, the scale is calcium carbonate.

[0045] Furthermore, the pulse magnetic field scale inhibition device provided in Example 1 is used to perform pulse magnetic field treatment on the aqueous solution.

[0046] Example 4 A process for inhibiting scale by treating an aqueous solution with a pulsed magnetic field, wherein the aqueous solution is treated with a pulsed magnetic field for 25 minutes; The concentration of calcium ions in the aqueous solution is 2 mmol / L; The frequency of the pulsed magnetic field is 1.25kHz; The ampere-turns of the pulsed magnetic field is 160NI; The duty cycle of the pulsed magnetic field is 20%.

[0047] Moreover, the scale is calcium carbonate.

[0048] Furthermore, the pulse magnetic field scale inhibition device provided in Example 1 is used to perform pulse magnetic field treatment on the aqueous solution.

[0049] Example 5 Different from Example 4, the concentration of calcium ions in the aqueous solution of this example is 5 mmol / L; Example 6 A process for inhibiting scale by treating an aqueous solution with a pulsed magnetic field, wherein the aqueous solution is treated with a pulsed magnetic field for 30 minutes; The concentration of calcium ions in the aqueous solution is greater than or equal to 8 mmol / L and less than 12 mmol / L; The frequency of the pulsed magnetic field is greater than or equal to 2 kHz and less than 3 kHz; The ampere-turns of the pulsed magnetic field is greater than or equal to 165 NI and less than 220 NI; The duty cycle of the pulse magnetic field is greater than or equal to 25% and less than 35%.

[0050] Moreover, the scale is calcium carbonate.

[0051] Furthermore, the pulse magnetic field scale inhibition device provided in Example 1 is used to perform pulse magnetic field treatment on the aqueous solution.

[0052] Example 7 A process for inhibiting scale by treating an aqueous solution with a pulsed magnetic field, wherein the aqueous solution is treated with a pulsed magnetic field for 20-30 minutes; The concentration of calcium ions in the aqueous solution is greater than or equal to 12 mmol / L and less than 20 mmol / L; The frequency of the pulsed magnetic field is greater than or equal to 3 kHz and less than 4 kHz; The ampere-turns of the pulse magnetic field is greater than or equal to 220NI and less than 300NI; The duty cycle of the pulse magnetic field is greater than or equal to 35% and less than 50%.

[0053] Moreover, the scale is calcium carbonate.

[0054] Furthermore, the pulse magnetic field scale inhibition device provided in Example 1 is used to perform pulse magnetic field treatment on the aqueous solution.

[0055] Experimental analysis 1. Effect of pulsed magnetic field on the initial decomposition temperature of calcium carbonate crystals The same 10L aqueous solution was prepared for three experimental groups and three control groups (experimental group 1, experimental group 2, experimental group 3, control group 1, control group 2, control group 3), and the concentration of calcium ions in the aqueous solution of each group was adjusted to 5mmol / L. The aqueous solution of the experimental group was placed in the pulse magnetic field anti-scaling device of Example 1 and treated for 25 minutes using the technical solution of Example 5; the control group was left standing for 25 minutes without any treatment.

[0056] The experimental and control aqueous solutions were respectively placed under appropriate conditions and uniformly heated to 70°C with continuous stirring. At the same time, sodium hydroxide was added to the experimental and control aqueous solutions to adjust the pH of the solution to 9, so that the pH of the solution was within a range that was conducive to the precipitation of calcium carbonate, thereby obtaining calcium carbonate crystals.

[0057] The dried calcium carbonate crystals were loaded into the sample tray of the thermogravimetric analyzer, the temperature was raised, and the change of the sample mass with temperature was observed. The initial decomposition temperature of the calcium carbonate crystals in the experimental group and the control group was measured respectively, as shown in Table 1 below.

[0058]

[0059] It can be seen from Table 1 that after the aqueous solution is treated with the technical solution of the present invention, the calcium carbonate crystals formed in the water significantly reduce the initial decomposition temperature of calcium carbonate relative to the untreated control group, with a reduction range of about 40°C. The most significant effect is the comparison between control group 3 and experimental group 1, in which the initial decomposition temperature of calcium carbonate crystals is reduced by 46°C, indicating that the pulsed magnetic field treatment with the parameters of the present invention has an effect on the thermodynamic properties of calcium carbonate crystals.

[0060] 2. Effect of pulsed magnetic field on pH of aqueous solution The pH values ​​of the pulse magnetic field scale inhibitor were read before and after the aqueous solution treatment of Examples 3-7, as shown in Table 2.

[0061]

[0062] It can be seen from Table 1 that there is no obvious change in the pH value of the aqueous solution before and after the treatment, which proves that the technical solution of the present invention will not significantly change the pH value of the aqueous solution while preventing scale, thereby maintaining the original properties of the aqueous solution and avoiding other problems caused by changes in pH value.

[0063] 3. Effect of pulse magnetic field on descaling rate of aqueous solution Aqueous solutions with different calcium ion concentrations were treated with a pulsed magnetic field for 25 min (Table 3). The calcium ion concentrations in the following aqueous solutions were measured using a calcium ion concentration meter. The descaling rate was calculated based on the change in calcium ion concentration before and after treatment: descaling rate = (calcium ion concentration before treatment - calcium ion concentration after treatment) / calcium ion concentration before treatment × 100%. The results are shown in Table 3.

[0064]

[0065] It can be seen from Table 3 that samples #1 to #11 adopt the technical solutions of Examples 3 to 6 of the present invention, and the descaling rates are 62.8% to 78.6%.

[0066] The best effect is when the calcium ion concentration in the aqueous solution is 2mmol / L and 5mmol / L (#5, #6), the frequency of the pulse magnetic field is 1.25kHz, the ampere-turns of the pulse magnetic field is 160NI, and the duty cycle of the pulse magnetic field is 20%, the descaling rate can reach 73.4% and 78.6%; among them, when the concentration is 5mmol / L, the frequency of the pulse magnetic field is 1.25kHz, the ampere-turns of the pulse magnetic field is 160NI, and the duty cycle of the pulse magnetic field is 20% (#6), the effect is the best (descaling rate 78.6%).

[0067] It can be seen from the experimental results of #8-#11 that for aqueous solutions with the same calcium ion concentration (5mmol / L), when the pulse magnetic field frequency, ampere-turns or duty cycle of the pulse magnetic field are adjusted, the descaling rate is significantly lower than that of #6. This proves that the present invention selects the optimal pulse magnetic field parameters for aqueous solutions with different calcium ion concentrations to maximize the descaling effect.

[0068] 4. Effect of different pulse magnetic field frequencies on scale removal The technical solution of the present invention is used to treat an aqueous solution with a calcium ion concentration of 5 mmol / L for 25 minutes. The ampere-turns of the pulsed magnetic field is 160NI and the duty cycle is 20%. The difference between the groups of samples lies in the different frequencies of the pulsed magnetic field, as shown in Table 4 below (the untreated group is scale formed naturally without being treated with the pulsed magnetic field).

[0069]

[0070] After the treatment, calcium carbonate crystals were obtained by the same method as above and observed by scanning electron microscope. Figure 5 As shown in the figure, 5a is the crystal morphology of calcium acid obtained from sample a, 5b is the crystal morphology of calcium acid obtained from sample b, 5c is the crystal morphology of calcium acid obtained from sample c, 5d is the crystal morphology of calcium acid obtained from sample d, 5e is the crystal morphology of calcium acid obtained from sample e, and 5f is the crystal morphology of calcium acid obtained from sample f.

[0071] As can be seen from the figure, the calcium acid crystals obtained in the untreated group (5a) are mostly spherical particles that are bonded together, with large particles, large numbers, and smooth surfaces. After treatment with pulsed magnetic fields of different frequencies, there are improvements, and the crystals are mostly small in size, dispersed in distribution, and irregular in shape. Among them, 5c and 5d have more significant effects. In terms of particle volume and crystal adhesion, 5d has the best effect.

[0072] 5. Effect of different pulse magnetic field ampere-turns on scale removal The technical solution of the present invention is used to treat an aqueous solution with a calcium ion concentration of 5 mmol / L for 25 minutes. The frequency of the pulsed magnetic field is 1.25 kHz and the duty cycle is 20%. The difference between the groups of samples lies in the different ampere-turns of the pulsed magnetic field, as shown in Table 5 below (the untreated group is scale formed naturally without being treated with the pulsed magnetic field).

[0073]

[0074] After the treatment, calcium carbonate crystals were obtained by the same method as above and observed by scanning electron microscope. Figure 6 As shown in the figure, 6a is the crystal morphology of calcium acid obtained from sample a, 6b is the crystal morphology of calcium acid obtained from sample b, 6c is the crystal morphology of calcium acid obtained from sample c, 6d is the crystal morphology of calcium acid obtained from sample d, and 6e is the crystal morphology of calcium acid obtained from sample e.

[0075] As can be seen from the figure, the calcium acid crystals obtained from the untreated group (6a) are mostly spherical particles that are stuck together and have large particles, large numbers, dense distribution, and smooth surfaces. After being treated with pulsed magnetic fields of different ampere-turns, there are different degrees of improvement, among which 6c has the best effect. The crystals are mostly small in size, dispersed in distribution, and irregular in shape.

[0076] 6. Effect of different pulse magnetic field duty ratios on scale removal The technical solution of the present invention is used to treat an aqueous solution with a calcium ion concentration of 5 mmol / L for 25 minutes. The frequency of the pulsed magnetic field is 1.25 kHz and the ampere-turns are 160 NI. The difference between the groups of samples lies in the different duty cycles of the pulsed magnetic field. The untreated group is scale that has not been subjected to the pulsed magnetic field, as shown in Table 6 below.

[0077]

[0078] After the treatment, calcium carbonate crystals were obtained by the same method as above and observed by scanning electron microscope. Figure 7 As shown in the figure, 7a is the crystal morphology of calcium acid obtained from sample a, 7b is the crystal morphology of calcium acid obtained from sample b, 7c is the crystal morphology of calcium acid obtained from sample c, 7d is the crystal morphology of calcium acid obtained from sample d, and 7e is the crystal morphology of calcium acid obtained from sample e.

[0079] As can be seen from the figure, the calcium acid crystals obtained from the untreated group (7a) are mostly spherical particles that are stuck together and have large particles, large numbers, dense distribution, and smooth surfaces. After treatment with pulsed magnetic fields with different duty cycles, there are different degrees of improvement, among which 7b has the best effect. The crystals are mostly small in size, dispersed in distribution, and irregular in shape.

[0080] 7. Comparison before and after pulse magnetic field treatment Aqueous solutions with calcium ion concentrations of 2mmol / L, 3mmol / L, 4mmol / L, and 5mmol / L were respectively divided into two groups (treated group and untreated group), one of which was treated with a pulsed magnetic field for 25 minutes using the technical solution of the present invention (frequency: 1.25kHz, pulsed magnetic field ampere-turns: 160NI; pulsed magnetic field duty cycle: 20%); calcium carbonate crystals were obtained using the same method as above, and the morphology of calcium carbonate crystals in each group was observed using a scanning electron microscope. The results are as follows Figure 8 As shown in the figure, 8a is the crystal morphology of the 2mmol / l untreated group, 8b is the crystal morphology of the 2mmol / l treated group, 8c is the crystal morphology of the 3mmol / l untreated group, d is the crystal morphology of the 3mmol / l treated group, 8e is the crystal morphology of the 4mmol / l untreated group, f is the crystal morphology of the 4mmol / l treated group, 8g is the crystal morphology of the 5mmol / l untreated group, and 8h is the crystal morphology of the 4mmol / l treated group.

[0081] As can be seen from the figure, for the four groups of samples with calcium ion concentrations of 2mmol / l, 3mmol / l, 4mmol / l and 5mmol / l, the crystals in the untreated group are mostly spherical particles that are stuck together and have larger particle size; after magnetic treatment, the crystal particles are obviously looser and less concentrated than those of the untreated group, and are mostly small and irregularly shaped particles; among them, when the calcium ion concentration is 5mmol / l, the effect is most significant (8h).

Claims

1. A process for inhibiting scale formation by treating an aqueous solution with a pulsed magnetic field, characterized in that: The aqueous solution is subjected to a pulsed magnetic field treatment for 20-30 min; The concentration of calcium ions in the aqueous solution is 0.5-20mmol / L; The frequency of the pulsed magnetic field is 1-4kHz; The ampere-turns of the pulsed magnetic field are 80-300 NI; The duty cycle of the pulsed magnetic field is 5%-50%.

2. A process for inhibiting scale by treating an aqueous solution with a pulsed magnetic field according to claim 1, characterized in that: The concentration of calcium ions in the aqueous solution is greater than or equal to 0.5 mmol / L and less than 8 mmol / L; The frequency of the pulsed magnetic field is greater than or equal to 1 kHz and less than 2 kHz; The ampere-turns of the pulsed magnetic field is greater than or equal to 80NI and less than 165NI; The duty cycle of the pulse magnetic field is greater than or equal to 5% and less than 25%.

3. A process for inhibiting scale by treating an aqueous solution with a pulsed magnetic field according to claim 2, characterized in that: The concentration of calcium ions in the aqueous solution is 2 mmol / L or 5 mmol / L; The frequency of the pulsed magnetic field is 1.25kHz; The ampere-turns of the pulsed magnetic field is 160NI; The duty cycle of the pulsed magnetic field is 20%.

4. The process for inhibiting scale by treating an aqueous solution with a pulsed magnetic field according to claim 1, characterized in that: The concentration of calcium ions in the aqueous solution is greater than or equal to 8 mmol / L and less than 12 mmol / L; The frequency of the pulsed magnetic field is greater than or equal to 2 kHz and less than 3 kHz; The ampere-turns of the pulsed magnetic field is greater than or equal to 165 NI and less than 220 NI; The duty cycle of the pulse magnetic field is greater than or equal to 25% and less than 35%.

5. The process for inhibiting scale formation by treating aqueous solution with a pulsed magnetic field according to claim 1, characterized in that: The concentration of calcium ions in the aqueous solution is greater than or equal to 12 mmol / L and less than 20 mmol / L; The frequency of the pulsed magnetic field is greater than or equal to 3 kHz and less than 4 kHz; The ampere-turns of the pulse magnetic field is greater than or equal to 220NI and less than 300NI; The duty cycle of the pulse magnetic field is greater than or equal to 35% and less than 50%.

6. A process for inhibiting scale by treating an aqueous solution with a pulsed magnetic field according to any one of claims 1 to 5, characterized in that: The scale is calcium carbonate.

7. A process for inhibiting scale by treating an aqueous solution with a pulsed magnetic field according to any one of claims 1 to 5, characterized in that: The pulse magnetic field scale inhibition device is used to treat the aqueous solution with a pulse magnetic field.

8. The process for inhibiting scale formation by treating aqueous solution with a pulsed magnetic field according to claim 7, characterized in that: The pulse magnetic field scale prevention device comprises a pH meter (1), a copper sheet (2), an electromagnetic coil (3), a liquid container (4), and a pulse power supply box (5); the positive and negative poles of the power supply of the pulse power supply box (5) are electrically connected to the inlet and outlet at both ends of the electromagnetic coil (3); the electromagnetic coil (3) is wound around the outer wall of the liquid container (4); the liquid container (4) contains a water solution to be treated; the pH meter (1) is movably plugged into the water solution to be treated for measuring the pH value of the water solution to be treated; and the copper sheet (2) is movably arranged at the bottom of the liquid container (4).

9. The process for inhibiting scale formation by treating aqueous solution with a pulsed magnetic field according to claim 8, characterized in that: The electromagnetic coil (3) is a copper coil wound with enameled wire.

10. The process for inhibiting scale formation by treating aqueous solution with a pulsed magnetic field according to claim 8, characterized in that: The electromagnetic coil (3) is a copper coil or an iron core copper coil.

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