Study On The Preparation And Performance Of Benzotriazole And Compound Corrosion And Scale Inhibitor

In recent years, with the development of water treatment chemicals industry, BTA also began to be used for carbon steel and other metal corrosion. Currently, reports about BTA used for carbon steel corrosion at home and abroad was less, and the corrosion mechanism for carbon steel was also unclear. In order to study the corrosion inhibition performance about BTA used for carbon steel, and effectively solve corrosion and scaling problems in industrial circulating cooling water system,an efficient composite corrosion and scale inhibitor without phosphate for circulating cooling water system was prepared. It was consisting of benzotriazole (BTA), acrylate,2-acrylamido-2-methyl propane sulfonic acid (AA/AMPS), zinc sulfate, Hydrolyzed Polymaleic Anhydride (HPMA) and sodium gluconate.In this paper, orthogonal experiment was conducted to optimize the best dosage and the best formula of composite corrosion and scale inhibitor would be determined. Corrosion and scale inhibition performances of the best composite corrosion and scale inhibitor were measured respectively by rotary coupon corrosion test and static scale method. And the benefits of economic and environmental of the best formula were also analysised. Finally, the corrosion and scale inhibition mechanism was discussed through the polarization curves, electrochemical impedance spectroscopy, scanning electron microscopy method and X-ray diffraction method. The results of the research are as follows.(1)The results showed that, the corrosion inhibition rate could reach94.61%when the dosage of BTA was100mg/L, and the scale inhibition performance of BTA was not obvious.(2)The best formula was consisted of BTA3mg/L, AA/AMPS6mg/L, zinc sulfate3mg/L, HPMA6mg/L and glucose sodium10mg/L.The corrosion rate of the composite corrosion and the scale inhibitor could reach92.02%and the scale inhibition rate could reach90.42%(3)The best formula could effectively disperse iron oxide, and had it could effectively inhibit the deposition of iron oxide.(4)According to the contrast of environmental and economic analysis, the composite corrosion and the scale inhibitor had the possibility of substituting phosphorus corrosion and scale inhibitor and it had little harm to the environment.(5)The results of polarization curves and electrochemical impedance diagram showed that the corrosion and scale inhibitor mainly inhibit the anodic reaction. The result of scanning electron microscopy analysis showed that a protective film was formed on the surface of the carbon steel to inhibit the corrosion. The results of XRD analysis and scanning electron microscopy analysis showed that the composite corrosion and scale inhibitor could damage the lattice structure of calcium carbonate, inhibit the crystal growth through normal rules. And it also could disperse the crystals, make the scale shape to be irregular and size to be smaller.