Biogas purification and liquefaction by means of a cryogenic upgrading process.

Transport sector represents one of the main responsible for greenhouse gas (GHG) emissions and natural gas (NG) could efficiently reduce them, especially in its liquid form (LNG) suitable for heavy-duty vehicles. Nevertheless, in certain regions, LNG is difficult to supply and biogas is actually used as feedstock gas. However, due to its high CO2 content, biogas needs to be purified. At present, several upgrading technologies are existing but since the final scope is the LNG production, cryogenic upgrading technology looks very promising. However, this technology is still in a developing phase. This study proposes a cryogenic upgrading process in which CO2 is removed and biomethane is liquefied (LBG) at the same time. Moreover, specific energy consumption is optimized by means of HYSYS simulation and a rough economical analysis is also performed to evaluate its attractiveness. As a result, cryogenic upgrading technology represents an interesting option for LBG production.