Screening And Performances Research On Multi-component Water Treatment Agent For Polymetallic System Of Cooling Water

Scaling,metal corrosion and biological slime are the main problems of industrial cooling water.Chemical dosing is the most recognized technology in industrial water treatment technology at present.In order to solve the problems of high phosphorus content,high price and single function in chemical dosing method,this paper adopts static scale inhibition method and dynamic hanging tablet experiment to carry out a series of compound experiments to obtain a compound water treatment agent without phosphorus and multi-function.The mechanism of the composite scale and corrosion inhibitor was studied by electrochemical technique,surface analysis technique and adsorption thermodynamics,and the effects of pH value and temperature on the scale and corrosion inhibition performance of the composite water treatment agent were studied.(1)Through preparatory experiments,five kinds of scale inhibitor monomers were screened,namely hydrolyzed polymaleic anhydride,polyepoxysuccinic acid,polyaspartic acid,2-phosphonic butane-1,2,4-tri carboxylic acid,sodium ethylenediamine tetramethylenediphosphonate,and four kinds of corrosion inhibitor monomers,namely lauryl sarcosine sodium,methyl benzotriazole,sodium citrate and imidazoline bisquaternary ammonium salt.Through a series of compound experiments,the formula with the best scale and corrosion inhibition performance was obtained.Its composition is HPMA 20mg/L+TTA50mg/L+BIS100mg/L.(2)The effect of composite scale and corrosion inhibitor is greatly affected by pH and temperature.In the range of pH 4-10 and temperature 40-80 C,the scale and corrosion inhibition rates are more than 85%.The selected composite formula has good adaptability to water quality changes,and can meet the requirements of scale prevention of circulating cooling water system and corrosion protection of common system of copper,iron and aluminum.(3)By means of SEM and XRD morphology analysis,it is inferred that the scale inhibition mechanism of the formula is as follows:by adsorbing the active sites of calcium carbonate scale crystals,the crystal structure of calcium carbonate scale crystals is destroyed,so that it can not aggregate and become larger,thus it can not form larger calcium carbonate scale;(4)Through thermodynamic calculation of adsorption,the results show that the scale and corrosion inhibitor formula is adsorbed on metal surface by chemical adsorption or physical adsorption combined with chemical adsorption,forming a single molecular layer,which protects the metal matrix from water and corrosive anions.The two inhibitor molecules complement each other in the film forming process of metal surface,which makes the monolayer more protective.