Mass Transfer Coefficient During Cathodic Protection of Low Carbon Steel in Seawater

Abstract

The aim of this research is to calculate mass transfer coefficient, kd, during cathodic protection of low carbon steel in neutral seawater (3.5% W/V NaCl in distilled water with pH = 7). Two types of cathodic protection were used: First: Sacrificial anode cathodic protection (SACP) were a pipeline of steel carrying seawater using zinc as a sacrificial anode and with variable temperatures ranged (0 – 45oC) and volumetric flow rate ranged (5 – 900 lit/hr). It was found that the kd increases with increasing temperature and volumetric flow rate of seawater, where kd ranged (0.24×10-6 – 41.6×10-6 m/s). Second: Impressed current cathodic protection (ICCP) technique adopting a rotating vertical steel cylinder in seawater with variable temperatures ranged (0 – 45oC) and rotating velocity ranged (0 – 400 rpm). It was found that the kd increases with increasing temperature and rotating velocity, where kd ranged (7.25×10-6 – 36.82×10-6 m/s).