Scale Mechanism And Experimental Study Of Swept Frequency Electromagnetic Field

In the actual circulating process of circulating cooling water,the solute concentration in water is caused by the constant evaporation and dissipation of water.In the past,a layer of scale has been produced on the inner wall of equipment and pipeline.The scale will increase the pressure drop in the pipeline and reduce the heat transfer efficiency of the equipment,it even greatly shortens the service life of the equipment when it is serious.The traditional methods of chemical anti-fouling can lead to the second pollution at the same time of high efficiency scale inhibition.Physical scale inhibition method represented by pulse electromagnetic scale inhibition method has been widely used because of its advantages of environmental protection and simple operation.Based on the background of pulse electromagnetic anti-fouling technology,this paper analyzed the factors affecting scale formation,and expounded the principle of electromagnetic scale inhibition technology from two aspects: the effect of electromagnetic field on hydrate ions and the effect of electromagnetic field on scale formation ions in water.It was concluded that the output frequency and magnetic induction intensity of power supply had an important influence on scale inhibition effect.The influence of coil turns,pipe material and diameter on magnetic induction intensity was simulated by ANSYS electromagnetic simulation.Comparing the magnitude and distribution of magnetic induction in the pipeline under different parameters,pipe material and pipe diameter,it provided the basis for the selection of the device in the next experiment.We built static and dynamic experimental platforms.Then we carried out static and dynamic experiments.The comparison of static and dynamic experiments showed that the flow rate had a certain influence on the scale inhibition effect.At the same time,by changing the output frequency of power supply,the influence of frequency on the conductivity,acidity and alkalinity of solution and particle size distribution was discussed.It was found that when the output frequency of the power supply was 65 kHz to 70 kHz,The conductivity of the two experimental solutions decreased by 384 ?m/cm and 675 ?m/cm,respectively,and the pH decreased by 0.67 and 0.77,respectively.At the same time,the average particle size of the particles in the two experimental solutions was the highest,reaching 14.21 ?m and 15.24 ?m,respectively.The thickness of scaling layer before and after the hanging piece experiment was measured by laser profile scanning instrument,and the scaling quality of hanging piece before and after the weighing experiment was measured by electronic balance.The structure of scaling layer before and after the electromagnetic field treatment was observed by scanning electron microscope.The results showed that when the input frequency is 65 kHz~70 kHz,the thickness of the fouling layer of the hanging piece was up to 3.64 mm,the scale distribution of the scale was the most dense,and the fouling quality of the hanging piece was also the largest at 39.78 g.The calculation shows that the scale removal rate reached 73%.It was thus concluded that the electromagnetic field in this frequency range had the best scale inhibition effect,the final electromagnetic scale inhibition technology provided certain parameter guidance.