F-3 The Effects of Selected Corrosion Inhibitors on the Fouling Characteristics of Cooling Tower Water

J. G. Knudsen, A. Abu-Al-Saud, and J. M. Chenoweth

Corrosion inhibitors are often added to cooling tower water to prevent the corrosion of the various metallic elements of the cooling water system. These are effective in preventing corrosion; however, they can, under some circumstances, be the source of fouling in heat exchangers. This report describes an experimental study at Oregon State University in which phosphate corrosion inhibitors are investigated relative to their effect on the fouling characteristics of a high hardness (1000 ppm) cooling tower water. The significant parameters—system pH, heater surface temperature, water velocity in the test section, and fouling inhibitor (organic phosphate, copolymer)—were systematically investigated. In addition, the effect of the presence of iron on the fouling characteristics of the water is reported. A total of 168 individual long-term tests is reported. It is shown that the fouling deposit evolved from the corrosion inhibitor additive in the water and that the extent and rate of fouling can be controlled to acceptable limits.