Study On The Inhibition Of CaCO₃ Fouling By Sodium Humate

The surface of electrical equipment is very easy to accumulate dust.The formation of dirt will reduce the heat transfer capacity and efficiency of heating machinery and equipment,resulting in excessive property losses.In this paper,calcium carbonate crystalline scale is taken as the research object.Calcium carbonate dirt is the most common and meaningful dirt in electrical equipment.In order to better reduce the harmfulness and heat transfer damage caused by the accumulation of calcium carbonate dirt on the heat transfer surface as soon as possible,the common way is to add scale inhibitor to the circulating water.Sodium humate has good anti scaling characteristics,non-toxic,easy to dissolve,zero environmental pollution to the ecological environment,which is in line with the current development trend of scale inhibitors.Based on experiments,density functional theory calculations and molecular dynamics simulations the scale inhibition characteristics of sodium humate on calcium carbonate are analyzed.The p H value conversion method and analytical chemical characteristic impedance method are selected to make it clear that sodium humate has good scale inhibition characteristics.Then,according to the net weight of the specimen,the temperature characteristics of sodium humate inhibiting the growth and development of calcium carbonate scale were discussed.The commercial service operation scale test shows that in the range of 0-100mg/L,the specific scale inhibition effect of sodium humate increases with the increase of ingredients and ambient temperature.When the concentration value is 100mg/L,the specific scale inhibition effect is the best,and when the temperature is 353 K,the specific scale inhibition effect is the best.The three experimental methods confirm that sodium humate can effectively inhibit the growth and development of calcium carbonate scale.On the basis of experiment and before molecular dynamics simulation,the chemical formula of sodium humate was calculated and analyzed according to density functional theory.According to the structure of sodium humate,the charge distribution,bond length geometry matching degree and field track energy of sodium humate are obtained.According to the calculation,it is found that the calcium in dolomite has good molecular formula fusion ability.Basically,the anti scaling ability of sodium humate is described,which makes up for the vacancy of molecular dynamics simulation.This test cannot clearly describe the basic concept of scale inhibition.In order to better explore the scale inhibition principle of sodium humate from the molecular formula level interaction between sodium humate and different molecular formulas（K,F,S）of different calcite crystal planes（110,104,1-10）carried out the analysis based on molecular dynamics simulations.First,the simulation simulates the interaction between the different crystal orientations of sodium humate and dolomite in the absence of water,and the adsorption configuration of the two,functional groups and mutual binding energy were analyzed.Comparing the binding energies of the three growth and development planes,we can find that there are significant differences in the binding energies of different crystal planes.The binding energy between sodium humate and calcite（1-10）crystal surface is the strongest,followed by calcite（110）crystal surface and calcite（104）crystal surface.In order to better study the scale inhibition characteristics of sodium humate group,the normal distribution function of oxygen molecules of different groups of sodium humate and calcium calcite was analyzed.According to the simulation analysis,it can be seen that the adsorption of the chemical formula of sodium humate is mainly due to the bond between the o molecular structure in the carboxyl group and hydroxyl group in the chemical formula chain and the lead in the middle of the CA molecule in the calcite crystal plane.Then,the standard of calcium ion crystal plan was discussed.The anti scaling characteristics of calcite and calcium bicarbonate in water are simulated,and the damage of anti scaling characteristics of calcite in water caused by temperature and glass transition temperature is simulated.Based on the analysis of the binding energy,normal distribution function and water exchange capacity of sodium humate,the adhesion principle of sodium humate is revealed.When the ambient temperature increases,the binding energy also increases.When the glass transition temperature increases,the binding energy increases with the increase of the glass transition temperature.On the myopia degree of the normal distribution function,it is observed that the three crystallographic orientations have very obvious peaks around r=2?,and the peaks of different crystallographic orientations are close to each other.On the three surfaces where the dolomite grows,the maximum value expands with increasing air temperature.At the same temperature,the adhesion working ability of activated carbon in the three crystal orientations of dolomite increases with the increase of the glass transition temperature.Finally,the damage of sodium humate to dispersed calcium bicarbonate in water was simulated.The chemical formula of sodium humate can reduce the adhesion and binding energy of dispersed calcium bicarbonate in the three crystal directions of calcite.For dispersed calcium bicarbonate,the first effective peak occurs above and below 2%,and the second peak occurs above and below 4 points For dispersed calcium bicarbonate,the first peak of Ca-O normal distribution function of sodium humate and calcite crystal surface layer occurs at 2 ?,and the second peak occurs at 4 points,but its maximum value is less than that of dispersed calcium icarbonate.There are ionic bonds between calcite,calcite crystalline surface and dispersed calcium bicarbonate.At the same time,there are also magnetic field force and van der Waals force.