More and more often, oil fields need to handle wet sour gases which contain high proportions of carbon dioxide and hydrogen sulphide. Furthermore, the liquid phase contains water with chlorides. Therefore, pitting corrosion and stress corrosion cracking may occur. Centrifugal compressors used on oil fields for increasing the pressure levels, require components which must be resistant to be efficient, but nevertheless cheap for an industrial solution. A corrosion resistant material with high mechanical characteristics is necessary. Duplex stainless steels which have been widely developed and experimented on off-shore applications, are a good way to achieve this challenge. They must be solution annealed to withstand severe corrosion conditions. This paper deals with the metallurgical aspects and the major influence of heat treatments, and with the manufacturing process of two major components : the casing and the rotor. This new centrifugal compressor, designed for a highly sour gas service, with 87% of acid compoaents, is dedicated to a process of sulphur elimination from the flare gas for environmental protection reasons. It has been operating since the beginning of 1995 by GASCO in Abu Dhabi.
Inconel Alloy 690-A New Corrosion Resistant Material