Corrosion inhibitors for refinery cooling water were subjected to four phases of testing: bench-scale, pilot plant, small size commercial cooling tower, and full plant-scale. Only three of the 50 inhibitors investigated in the past nine years were given full-scale trial. Of these, only the chromate type proved satisfactory in all phases of testing. Organic chromates were found to be particularly effective for the river water used in the refinery concerned. Phosphates, while exhibiting fair corrosion protection, had the disability of depositing scale, even at low pH values.
Tests were run for both carbon steel and Admiralty metal. Metal penetration rate and scale deposition data are given for specimens used in bench and pilot-plant tests in the presence of phosphate and chromate inhibitors. 5.8.1
