Study On The Influence Of Thermal Resistance Of CaCo₃ And CaSo₄ Fouling Under The Action Of Electric Field

The phenomenon of heat exchanger fouling frequently occurs in life and industry.On the heat exchanger,the heat transfer capacity is reduced by fouling,that flow resistance of the working fluid is increased and the safety of the equipment is reduced,then a large amount of economic loss is generated in industrial production.At present,various descaling methods have been studied in our country and foreign.The static resistance scale method is one of them and has received much attention.The advantages of static resistance scale method are non-toxic,non-polluting,high efficiency,environmental protection and energy saving.Therefore,it indicates the direction for future in industrial circulating cooling water scale inhibition.In order to study the effect of electric field on the fouling characteristics of crystallization,we mainly select two typical crystallization scales by the experiment that is CaCO3 and CaSO4.The ring electrode was used in the experimental section to study the effect of the electrostatic field on the fouling characteristics of different concentrations of CaCO3 and CaSO4.The electric field was in the form of a non-uniform electrostatic field.The fouling resistance line was obtained by measurement during the experiment;the quantified fouling resistance was obtained by the experimental test piece;the final scaling phenomenon was obtained by macroscopic observation;the microscopic crystal morphology was changed by SEM that the pictures were observed.In summary,different concentrations of CaCO3 and CaSO4 fouling properties were finally analyzed in different non-uniform electric fields.The experimental results show that the effect and trend of non-uniform electrostatic field on different concentrations of CaCO3 and CaSO4 fouling characteristics that are similar.With the increasing of the inhibition voltage of fouling,the asymptotic values of the fouling resistance show a trend that lines decrease first and then increase.The scale inhibition effect is increased firstly and decreased finally.In the range of this experiment,the 250 V is the best scale inhibition voltage of CaCO3 fouling,because of the minimum concentration of CaCO3 at the voltage at 0.4 g/L and 0.5 g/L,the rate of declining of the fouling resistance were 79.29%and 74.83%respectively,and the deposition quality decreased that was 72.85%and 81.95%;the 5000 V is the best fouling inhibition voltage of CaSO4 fouling.At the concentration of 3.5 g/L and 4.5 g/L,the rate of declining of the fouling resistance were 68%and 22.15%respectively,and the deposition quality decreased that was 79%and 35.6%,respectively.The CaCO3 and CaSO4 fouling can be inhibited by the non-uniform electrostatic field,the suitability and efficiency of CaCO3 fouling are higher than CaSO4 fouling,which has higher stability and practicability.