Corrosion of Iron-Nickel Base and Titanium Alloys in Aerated Geothermal Fluids

Abstract

Worst case corrosion occur in geothermal steam and steam condensate when these fluids exposed air. The resultant corrosion can include dissolved sulphides and a range of oxidised s p i e s as well chlorides carried over separators or dissolved in direct contact cooling Pitting corrosion, crevice corrosion and corrosion cracking tests of austenitic. duplex and high-nickel stainless steels,iron-nickel base alloys and titanium alloys were conducted in aerated high temperature fluids using ASTM type U-Bends. Laboratory tests of 304 and 316 austenitic stainless steelswere conducted at lower temperatures in simulated geothermal fluids using the slow rate technique. Resistance to pitting and SCC is dependent on alloy composition and can using the Resistance Equivalent formulation, PRE = 3.3 Mo + 16 N together with an understanding of the influence of nickel on SCC. Environmental parameters which corrosiveness, in addition chloride are partial pressure of oxygen, hydrogen sulphide and temperature.