Geothermal Corrosion and Corrosion Products

Abstract

The corrosion of carbon steels in geothermal fluids containing significant concentrations of :.adherent layers of corrosion products. These films are essential to the corrosion resistance of carbon steel yet they also contribute to heat exchanger fouling, valve fouling and orifice restrictions. and often results in formation of thick, Carbon steel and low alloy steel corrosion rates are reported for bore fluid (two phase), separated water, separated steam, and wet steam der ived from the geothermal field at Broadlands, New Zealand. Methods are described which permit calculations of corrosion product thickness from material loss determinations obtained using flat coupons and cylindrical Corrosometer probes. Corrosion rates and estimated cor rosion product formation rates are compared and discussed, with reference to pitting propensity and corrosion product adhesion. Differences in corrosion performance of differing corrosion monitors are explained.