Controlling evaporation of liquid CO2 during transport as part of CCS

In Europe, deployment of large-scale carbon capture and storage (CCS) with storage in an underground geological formation will in practice imply off-shore storage. This implies separation, purification and liquefaction of CO2 and, after transport to a harbour facility, loading into a ship for transport to the storage site, a trip that may take several days. The topic of this paper is how to address the evaporation of some of the liquefied CO2 caused by heat leaking into the storage, resulting in rising pressure and temperature that should
be controlled. First, this paper will assess the dependence of liquefied CO2 evaporation with time (boil-off rate,
BOR) on starting (low, medium or high) pressures/temperatures and heat ingress, and the rate of pressure and temperature increase as a result of it. Secondly, it will suggest alternatives to re-liquefaction during the
transport. The latter could involve, for example, the use of zeolite or other sorbent, or adding small amounts of a component with slightly different thermodynamic properties to the CO2. As the first part of the paper shows,
based on the behaviour of pure CO2 there may not be a need for worries or action since the pressure rise is
very modest even after several days. The work also shows that small amounts of impurities may have
significant effects, emphasising the importance of pre-transport processing.