| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To further secure the corrosion prevention of carbon steel piping used for a piping system, particularly for the piping of a heat exchanger, and to attain the elongation in the service life of the piping and the reduction in the man-hour for a maintenance check thereby. <P>SOLUTION: In the subject method, at the time when aminotrimethylene phosphonic acid (ATMP) and bivalent metal ions (M<SP>2+</SP>) are added to cooling water, and corrosion prevention for carbon steel piping is performed, the molar ratio between the aminotrimethylene phosphonic acid and the bivalent metal ions, M<SP>2+</SP>/ATMP is controlled to 2 to 6, and further, the concentration of the aminotrimethylene phosphonic acid is controlled to≥50 ppm by mass ratio. It is suitable that, as the bivalent metal ions, zinc ions are used, the cooling water comprises, by mass ratio, 30 to 150 ppm sodium chloride and 0.5 to 1.5 ppm sodium hypochlorite, and the concentration of the aminotrimethylene phosphonic acid is controlled to 50 to 250 ppm. <P>COPYRIGHT: (C)2006,JPO&NCIPI</p> |
