Within the project COORAL (German acronym for “CO2 purity for capture and storage”) studies on pipeline steels exposed to circulating supercritical impure CO2 have been carried out. For this purpose, a loop consisting of compressors, flow meter and two autoclaves was constructed. In order to simulate the real conditions in pipelines, impurities such as H2O, CO, SO2, NO2 and O2 were added to the CO2 stream before compression. Exposure experiments were carried out with steel specimens placed in the autoclaves. Carbon steel L360NB, pure iron X20Cr13, X46Cr13, X2CrMnNiN22-5-2 and alloy 31 have been exposed to circulating (flow rate 4 L/min) supercritical impure CO2 for one week at 60 °C and 10 MPa Surface analysis and weight loss experiments in order to determine the corrosion products and the corrosion rates showed that the impurities cause corrosion problems. Slight general corrosion by L360NB and soft iron was observed. The initiation of pitting corrosion was observed at the surfaces of the materials X20Cr13, X46Cr13, X2CrMnNiN22-5-2. No visible signs of corrosion have been observed on alloy 31.

Subject
Steel surfaces, Water, Materials, Corrosion rate, Autoclaves, Aqueous environments, Pipelines, Iron, Substrate surfaces, Corrosion products, Surface analysis, Impurities, Steel
Keywords:
supercritical circulating CO2, impurities, exposure test, corrosion
Government work published by the Association for Materials Protection and Performance (AMPP) with permission of the author(s). Positions and opinions advanced in this work are those of the author(s) and not necessarily those of AMPP. Responsibility for the content of the work lies solely with the author(s).
2013
GOV
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