| 摘要 |
<p>The present invention provides a method for suppressing corrosion in a closed cooling water system, which does not require a germicide and can reduce the amount of used nitrous acid (salt). The method for suppressing corrosion in a closed cooling water system suppresses the corrosion of an iron member and a copper member by adding nitrous acid in the closed cooling water system, and has 9-10.5 of pH, 25-150 mg/l of a nitrous acid concentration, and 0.2-10 mg/l of an azole compound concentration. In addition, a hydrophobic group-substituted nitrogenous unsaturated heterocyclic compound can be added. [Reference numerals] (1) Sample tube;(2) Electric heater;(4) Sample water tank;(7) Supply water tank</p> |
