chapter  2
Technology for Carbon Capture and Geologic Sequestration
Pages 35

As the previous chapter briefl y explained, the process of carbon capture and sequestration (CCS) includes three steps: capture of carbon dioxide (CO

transport of the captured CO 2 to an injection site, and injection of the CO

deep underground, where it is sequestered from the atmosphere. These steps were illustrated in Figure 1.7. In the fi rst step, CO

sources using a capture technology suited to the facility (described in Sections 2.2, 2.3, and 2.4). This CO

from the combustion and capture processes, is then dried, compressed, and cooled. Depending on the temperature, it is converted from a gas to a liquid or supercritical fl uid. This fl uid is moved from the site of capture to the site of injection, typically by pipeline (described in Section 2.5), although tanker ships (similar to LNG tankers) could also be used in some cases.1 Once it is delivered to the sequestration site, the CO

below the surface that the CO 2 remains as a supercritical fl uid. On continents,

assuming typical temperature and pressure gradients, the minimum depth that meets this criterion is typically 800 m or 2,600 ft. The precise minimum depth varies from one location to another.2