Parametric Studies of the Formation of Calcareous Deposits on Cathodically Protected Steel in Seawater

Abstract

A first principle mathematical model has been used to study the effects of ocean environment and cathodic protection on the formation of calcareous deposits and their ability to reduce the cathodic current density. These parameters include applied potential, rotation speed, temperature, salinity, and depth. The results showed the applied potential strongly influences the formation of calcareous deposits and their ability to reduce the cathodic current density. Among the environmental factors, rotation speed has the most influence on the cathodic current density. Salinity slightly influences the cathodic current density over the range of interest. Temperature is much more influential than salinity on the ability of calcareous deposits to reduce the cathodic current density. The results from modeling showed the formation rate of calcareous deposits is much lower at 5°C than at room temperature. The depth is very critical not only to cathodic current density but also to the formation of calcareous deposits in seawater. The formation of calcareous deposits would be expected to be slower and the deposits would contain more in deep water.