Carbon Dioxide Transportation

For many CCS projects, transportation may be via existing carbon-manganese steel pipelines, sometimes end-of-life oil or gas pipelines repurposed for this role. Dry supercritical carbon dioxide would not corrode these pipelines as long as the relative humidity was less than 60% even in the presence of N2, NOx and/or SOx contaminants.

The water solubility limit in high-pressure CO2 (500 bar) is 5000 ppm at 75°C and 2000 ppm at 30°C. Methane lowers the solubility limit, and H2S, O2 and N2 may have the same effect.

It is unlikely to be practicable to transport wet CO2 in low-alloy carbon steel pipelines because of potential high corrosion rates. If the CO2 cannot be dried, it may be necessary to build the pipeline of a corrosion-resistant alloy (CRA). This is current established technology.