Abstract
Corrosion of carbon steel in the H2S partial pressure range of 1-20 bar was studied in a series of autoclave experiments. CO2 was also present at partial pressures of 1-20 bar. Experiments were run at temperatures in the range of 10-120 deg C. The test solutions consisted of high-salinity brine (100 g/L NaCl, 150 ppm bicarbonate) and low-salinity condensed water (0.1 g/L NaCl). The duration of the tests was typically 14 days. Both weight loss corrosion and localized corrosion data were obtained. The entire surfaces of the exposed coupons were scanned with a 3D profilometer, obtaining detailed data on localized corrosion morphology, pit frequency and pit depths. The results are discussed on the background of existing literature. A few sources in literature have reported increased localized corrosion risk with high H2S partial pressures, but there are also published data showing that the effect of increasing the H2S level is minimal above a certain level. This is consistent with the findings in the present study. Also, it was found that the presence of CO2 played a minor role in these H2S-dominated environments.
