Compounding, Performance and Mechanism Analysis of Scale and Corrosion Inhibitor of Low Phosphorus Environment - Friendly Circulating Water Treatment

Abstract

For the purpose of solving the problem of corrosion and scaling of the industrial circulating cooling water system, the biodegradable materials such as carboxyethylthiosuccinic acid (CETSA), acrylic acid - 2 - acrylamide - 2 - methylpropanesulfonic acid copolymer (AA/AMPS), polyepoxysuccinic acid (PESA), 2 - phosphonobutane - 1,2,4 - Tricarboxylic acid (PBTCA), sodium lauroyl sarcosinate (LS) and methylbenzotriazole sodium salt (TTA - Na), as well as zinc sulfate heptahydrate were used as components to compound composite scale and corrosion inhibitors. Meanwhile, the corrosion and scale inhibition properties of inhibitors were tested according to GB/T 16632-2008 and GB/T 18175-2014. Results showed that the optimized formula of scale and corrosion inhibitors was 10 mg/L CETSA, 14 mg/L AA/AMPS, 20 mg /L PESA, 4 mg/L PBTCA, 10 mg/L LS, 10 mg/L TTA - Na and 1 mg/L ZnSO4·7H2O (calculated using the content of Zn2+). In the case of the optimal inhibitor, the scale inhibition rate was 96.35%, the corrosion rate was 0.007 2 mm/a, the corrosi on inhibit ion rate was 99.68%, and the corrosion and scale inhibition performances were good and environment - friendly. Moreover, the electrochemical test results showed that the composite scale and corrosion inhibitor was a cathode type corrosion inhibitor. The SEM observation revealed that the composite scale and corrosion inhibitor could form a protective film on the surface of carbon steel, which could be adsorbed on the calcium carbonate crystals to suppress their development.

Keywords

• scale and corrosion inhibition|low phosphorus|circulating cooling water treatment|environment - friendly|compounding