Corrosion of Pipeline and Compressor Materials Due to Impurities in Separated CO2 from Fossil-Fuelled Power Plants

It is well known that transporting CO2 via pipelines even in the supercritical state is not a problem from the corrosion point of view, as long as CO2 is almost pure and dry. Depending on the CO2 separation technology, however, the untreated CO2 stream contains also various impurities such as oxygen, sulphur oxides, nitrogen oxides, carbon monoxide and water. These impurities can cause severe corrosion to pipeline and compressor materials. To avoid corrosion in existing pipeline systems the transported CO2 is usually purified and dried, which causes high energetic and financial expenditures. The aim of this investigation is to identify the corrosion potential of impure CO2 on pipeline and compressor materials as well as to determine the required purity minimum of the CO2 stream from the power plant, from the corrosion point of view. This is done by performing experiments with different materials exposed to impure CO2. It is shown that some impurities enhance the corrosion and with a combination of oxygen, water and nitrogen oxide significant corrosion rates occur.