The dehydration of natural gas consists of water removal that is associated with the natural gas in form of vapor. The removal of water prevents the formation of gas hydrates and reduces corrosion in
pipelines and components. The present study addresses the
aggressiveness of the environment and the possible prevention methods in a corrosive environment containing MEG (Monoethylene Glycol) in
presence of a neutralizer (Monoethanolamine MEA). The materials used were ASTM A106 gr. B and A285 gr. C, steels that are extensively used by the oil industry in the construction of pipelines and pressure vessels. Corrosion rate measurements were carried out through weight loss (in situ) measurements, under normal operating conditions at different steps of the process: rich glycol-chiller (-6°C), rich glycol filter (60°C) and lean glycol-reboiler (95°C). The laboratory tests were performed by
means of linear polarization resistance (Rp) under the presence of MEG, MEG/H2O and MEG/MEA ratios at 25, 60 and 93°C using a nitrogen atmosphere. For rich glycol at high temperatures, both steels showed a relatively high corrosion rate (0.45 mm/y) and internal pitting. This investigation suggested that the presence of rich MEG at low pH increases the corrosion rate and may affect the susceptibility of pitting of the steel. An optimal neutralizer dosage is an important factor to prevent the corrosion of the components. The morphology of the corrosion products and the characteristics of pitting were studied employing SEM-EDS techniques and optical microscopy.