Corrosion and Fouling of Chromium and Nickel Alloys in Petrochemical Environments

Corrosion and fouling is encountered in various locations and environments in operating petrochemical plants despite the fact that process streams are primarily composed of hydrocarbons.  An electrochemical high temperature and high pressure facility is used to study the corrosion and fouling behaviour of low-alloy, stainless and exotic alloy steels in several petrochemical environments.  Electrochemical techniques including cyclic voltammetry, open circuit potential and electrochemical impedance spectroscopy are used to study the effect of temperature, water concentration, chromium and nickel concentration on the initiation of corrosion/fouling on various alloyed steels in several petrochemical solutions (i.e. naphtha, raw pyrolysis gasoline and quench tower bottoms). 

Experiments are conducted using a quasi-reference Ag metal electrode.  Previous results on carbon and low alloy steels suggest that corrosion rates vary with conductivity, which are controlled, by varying the concentration of water.  Scanning electron microscopy and energy dispersive X-ray analysis (SEM/EDX) is used to look at the nature of the deposit formed after applying the aforementioned electrochemical techniques.