Performance and Application of Corrosion Inhibitor TH-658B in High Hardness and High Alkalinity Water

Aiming at the scaling and corrosion problem of high hardness and alkalinity water in north and northwest of China, a new type of scale and corrosion inhibitor TH-658B was developed. The performance of TH-658B was evaluated by means of scale inhibition test, gradient concentration test and rotary coupon corrosion test. The results show that the calcium carbonate scale inhibition rate of TH-658B was higher than ATMP and HEDP under the same concentration condition. The calcium carbonate and calcium sulfate scale inhibition rate of TH-658B can meet the standard requirements of Q/SY 126-2007. Gradient enrichment test results indicate that the summation of calcium hardness and total alkalinity could reach more than 1500 mg/L as TH-658B existed in water, which is much higher than the standard requirements of GB50050-2007. Furthermore, TH-658B has good inhibition corrosion performance for carbon steel, stainless steel and copper in high hardness and alkalinity water. The corrosion rates for carbon steel, stainless steel and copper were 0.0356, 0.0018 and 0.0012 mm/a, respectively, meeting the requirements of GB 50050-2007. TH-658B has been applied to circulating cooling water of a power plant for one year. It has proved that TH-658B had good inhibition corrosion and scale performance, and it can be used in circulating cooling system in which calcium hardness and alkalinity is up to 1500 mg/L.