Mechanism Analysis And Effect Research Of Pulse Electromagnetic Field Scale Inhibition

Due to the loss of water and the change of temperature during the cycle of cooling water,the scale is easily generated in the heat exchange equipment,resulting in the problems of reducing the heat transfer efficiency,increasing the pressure drop and damaging the equipment.Because chemical scale inhibition method need high cost and cause second pollution to environment,physical scale inhibition method is the trend of development of circulating water scale inhibition.The pulsed electromagnetic field scale inhibition equipment is excellent because of its convenient installation,simple operation and convenient operation.In this paper,the formation process of scale and the factors affecting the formation of scale were analyzed.The mechanism of pulse electromagnetic field scale inhibition was discussed from two aspects of the effect of electromagnetic field on water solvent performance and calcium carbonate crystals.It was found that the frequency and the intensity of the induction magnetic field are two important factors that affect the effect of scale inhibition.The ANSYS simulation software was used to analyze the effect of pipe materials on the strength of induced magnetic field in the pipe.It was found that non-magnetic materials such as PVC pipe should be selected as the winding pipe in the electromagnetic field scale inhibition system.The experiments were conducted to explore how the frequency of the output signal,the number of winding turns and the change of the pipe diameter effect on induction magnetic field intensity in the pipe.It was found that the intensity of induction magnetic field decreases with the increase of frequency and pipe diameter,and the change of winding coil number has little effect on the intensity of induction magnetic field in the pipe.The static test was carried out from two aspects: solubility of aqueous solution,the precipitation and growth rate of the calcium carbonate crystals affected by pulse electromagnetic field.The effects of water flow rate,temperature,and other factors on the experimental results were excluded.The experimental results showed that the solubility of calcium carbonate increased,the precipitation rate and growth rate of crystals increased by the action of the pulsed electromagnetic field.The dynamic tests was conducted to study the how the changes of scale inhibition parameters affect the scale inhibition effect.The supersaturated solution with hardness of 1000 ppm was used as experimental water.The experimental results showed that the frequency and the number of winding coil will affect the scale inhibition effect.When the frequency is moderate,the scale inhibition effect is good,and the increase in the number of winding coil will increase the scale inhibition effect.Comparing the effect of the frequency and number of turns on the scale inhibition effect in the experiment,it was found that when the output frequency of the power supply is 2 kHz and the number of turns of the coil is 90,the scale inhibition effect is better and the scale inhibition rate reaches 90.6%.