Study On The Effect Of Scale Inhibition On Circulating Water Of Power Plant With Flow Velocity Change Under Electrostatic Field

By using the“Double Channel Industrial Circulation Cooling Water Dynamic Simulation Test Bench”and“Ion Rod Scale Inhibitor Processor”,the influence of electrostatic field,flow rate related to the scale control effect of power plant circulating cooling water and scale inhibition mechanism were investigated based on the change of the voltage and circulating cooling water flow rate.In the conditions of 0.45m/s,0.60m/s,0.75m/s,and 0.89m/s,the dynamic simulation experiments of scale inhibition at 4000V and 6000V were performed.The experimental results present that the resistance is 4000V.The scale effect is better than that of 6000V.Amongst,the voltage at 4000V and the flow rate at 0.89 m/s have the optimal scale inhibition rate,which the average scale inhibition rate is 55.82%.With the voltage at 6000 V and the flow rate at 0.45 m/s,the average scale inhibition rate was only 19.9%.By analyzing the hydrogen bond and the changes of the electric dipole moments with the effect of the electrostatic field,the low energy,provided by the electrostatic field of the ion rod basically,has no effect on the polarization of water molecules.Therefore,the effect of flow rate on the CaCO₃ crystal and the turbulent layer,transition layer and cohesive layer of the water flow in the copper tube should be analyzed from the perspective of the electrostatic field in the analysis of the effect of electrostatic field on the aqueous solution.Scanning electron microscopy and X-ray diffractometry were used to determine the crystal structure of scale deposits and descales of CaCO₃,and the data were obtained regarding CaCO₃ crystals.The results show that the main phase of CaCO₃ scale is aragonite and calcite,and its Chinese rock content is relatively large.The scale grain size is larger than that of scale grain,and the crystal surface area of scale adhesion is smaller than the grain surface distance of descale.Provided by the scale adhesion of the experimental group,the crystallinity of CaCO₃ under the action of 4000V voltage is generally lower than that of 6000V.Indicating the decrease of the crystallinity of CaCO₃scale under the action of the electrostatic field of the ion rod,the scale inhibition effect can be promoted.In the descaling of the control group,the crystallinity decreases a long with the increase of the flow rate,and the scale inhibition rate increases following the increase of the flow rate.Therefore,the circulating water flow rate has a great influence on the crystallinity and the scale inhibition rate.Experiments show that,although the viscosity coefficient?of the aqueous solution increases,the thickness?of the viscous underlayer increases in the action of the electrostatic field.But when the circulating water velocity increases,the?decreases.On the other hand,the thickness of the viscous underlayer?is much stronger.The final effect results in a decrease in the thickness?of the viscous underlayer,which is limited by the flow velocity of the circulating water.Calculations show that the viscous underlayer is relatively thick,and convective mass transfer is the main factor affecting the transport of scale formation ions at a low flow velocity of 0.45 m/s.Therefore,the tangential stress of the fluid affects the precipitation and scaling of CaCO₃ crystallites.The impact is smaller,and the scale inhibition rate is relatively low.At a high flow rate of0.89 m/s,the viscous underlayer is correspondingly thinned.The surface reaction of the crystal controls the fouling process.At this time,the flow rate increases,as well as the fluid tangent.As the stress increasing,the scour capability of the CaCO₃ crystallites are increased,and the same as scale inhibition rate.Therefore,relative to the electrostatic field,the change of circulating cooling water flow rate has a greater effect on the scale inhibition rate.