1. Extraction of CO2 from a mixture

If we wanted to avoid extracting CO ₂ from fumes resulting from combustion, whose concentration varies between 3 and 15% vol, we could store these fumes directly underground, but given the volumes involved the cost would then be unacceptable. This is why it is necessary to remove the CO ₂ and transport it as an almost pure gas under pressure (110 bar or more) to a geological storage site (for example, a saline aquifer, a depleted oil or gas extraction site, a mineralization...).

The main techniques for separating the components of a mixture are