Prediction of CO2 Corrosion Rate

The corrosion rate of carbon steels in COj -saturated water may be evaluated according to the de Waard and Milliams formula, where the corrosion rate is an exponential function of COj partial 

For high pressures, it is recommended to substitute the partial pressure with the fugacity, defined as  

The validity limits under which the above formula was originated are  

The fitness of this formula has also been confirmed for COj partial pressures much higher than the original experimental work. 

In wet COj-containing pipelines and flowlines, glycol is often injected to prevent hydrate formation. Glycols have a significant inhibitive effect on corrosion. The reduction of the expected corrosion rate due to the presence of triethylene glycol (TEG) can be conservatively expressed by F(g)  

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