Electromagnetic Field Effect On The Calcium Carbonate Scale Of The Tube Side Of Exchanger

In industrial production, the fouling phenomenon of circulatingwater affects and does great harm to the on-site heat-exchangeequipments, which will cause a series of technical and economic issues.Of the traditional methods of removing and inhibiting fouling, there aresome disadvantages, such as environmental pollution, low efficiency,high costs and so on. Recently, frequency electromagnetic fieldanti-fouling technology has received great attention because of itsadvantages of low investment, quick effectiveness, simple operation, zeropollution, etc. Based on the evaluation electromagnetic effect onlinemonitoring experiment rig of fouling prevention, the effect of theelectromagnetic field on the CaCO3fouling behavior was studied. Thecrystallization of CaCO3was studied by monitoring the changes of fouling resistance and the water quality parameters of the treated solutionand precise analysis of the scale sample. Here is the detail:First of all，based on the evaluation electromagnetic effect onlinemonitoring experiment rig of fouling prevention, we research into theinfluences of different electromagnetic field types and differentelectromagnetic frequencies on the features of the fouling on the heatexchange surface; and make comparisons among the anti-fouling results.In the precise analysis, the crystallization of CaCO3was characterized bySEM of Quanta200, XRD of Quanta200and microscope of DMM-200C.The results show that electromagnetic field can reduce the scaling rate ofthe surface of heat exchanger, the mass fraction of the calcite of scalesample reduced to40.55%from100%, the mass fraction of the aragoniteincreased to55.45%.Secondly, comparative analysis of the essential characteristic of conductmetric titration curve with the calcium carbonate fouling processdynamic through conductivity titration experiments. Lots of experimentresults showed that: under the influence of electromagnetic field, thecritical supersaturation ratio decreased, nucleation rate increased andnucleation induction period shortened.Again, the influence of the electromagnetic field on foulingresistance and water quality parameters were investigated. Therelationship between water parameters and fouling resistance wasquantitative expressed by using the correlative degree analysis andbalanced adjacent degree.Finally, the fouling resistance prediction based on multivariate linearregression, principal component regression and neural network wererealized. The average relative error of the three models is0.151%,0.139%and0.140%. The results show that the three prediction models can accurately achieve water quality parameters to predict fouling growthcharacteristics, can be used for general industrial analysis. Bycomparison, the principal component regression model can get specificmathematical relationship expression compared with the neural networkprediction model, the principal component regression model is moreprediction accuracy than the multiple linear regression model. Therefore,the principal component regression model is superior to the twopredictive models.Researches above are the key of studying fouling-formingmechanism, revealing the forming process of fouling on the surface ofheat-transmission equipments under electromagnetic effects, andexploring the mechanism of electromagnetic inhibition and the effectevaluation function. All these are of great importance to prepare forresearch and development of the adaptive electromagnetic equipment with closed-loop control system in which inhibition effect is objectivefunction and to promote the development of electromagnetic watertreatment technology.