Pipeline Transport

Transport of CO2 by pipeline is common in the United States where some 3000km of CO2 pipelines exist. These have been in use since the early 1970s for transport of CO2 for Enhanced Oil Recovery (EOR) projects.

All large scale pipelines are currently designed for supercritical/dense phase CO2 transport. This avoids solidification of the CO2 and allows it to be pumped as a liquid. Typically pressures are kept above 10 MPa by recompression stations at intervals along the pipelines.

Impurities such as methane, hydrogen sulphide, nitrogen and water also affect the properties of CO2. Water is the most critical of these as CO2 dissolved in water creates an acidic solution that attacks metal pipelines. Additionally solid ice-like CO2 hydrate crystals can form when CO2 and water mix causing pipeline blockages and for these reasons the CO2 must be dried before transportation.