Patent ID: 7517493
Filing Date: 2009-04-14
Classification: C02F,C23F

Abstract:
1. A method for inhibiting corrosion of a metallic substrate in an aqueous system wherein said aqueous system derives water, and silica contributed by source water, from make-up of source water, the method of the present invention comprising the steps: a) removing polyvalent metal (PVM) ions from said source water; b) controlling the monovalent metal (MVM) ion concentration of the aqueous system water such that said aqueous system water possesses an MVM ion concentration that exceeds the soluble silica concentration; c) elevating and maintaining the pH of said aqueous system water such that said aqueous system water possesses a pH of approximately 7.0 or greater; and d) concentrating said source water and its natural silica content by evaporation of makeup water in an aqueous system where the system water temperature is higher than the makeup water temperature, and said system water is circulated in contact with heat transfer surfaces that elevate such portion of water to even higher temperatures; wherein e) performing steps a)-d) operatively transforms said natural silica content to corrosion inhibiting silica forms.