| Abstract |
Abstract thermodynamic stability of iron oxide and sulfide in with e thermal steam is presented terms of log For Wairakei high pressure steam lines corrosion products (magnetite-pyrite) observed corresponds closely to that expected from theory, The overall corrosion process consists in the cyclic dissolution of metallic Iron on contact with liquid condensate formed through heat loss from the pipe walls, subsequent increases in and iron contents of the condensate lead to the deposition magnetite and later on pyrite until equilibrium between scale deposit, condensate and steam is reached. fresh condensate, however, leads to undersaturation with respect to the scale deposit and to the dissolution of the protective layer of magnetite further downstream until bare metal is exposed again and the cycle is repeated. Kawerau and Broadlands, higher partial pressures are to lead to the formation of iron-sulfides pyrrhotite-pyrite). Techniques to control pipeline corrosion include suppression of condensate through superheating of the steam carried and the addition of aluminium and silica through of separated thermal water or the slow of cement or surfaces in contact with the condensate to promote the a protective |