Dehydration requirements for CO₂ and impure CO₂ for ship transport

CCS is expected to become an important contribution to the mitigation of carbon dioxide emissions. Transportation of CO₂ from the capture site to the permanent storage reservoir plays a key role, and transportation by ship is now viewed as a relevant alternative for certain combinations of captured CO₂ volume and distance.

This paper presents experimental equipment, methods and new results for the water content of carbon dioxide and impure carbon dioxide in equilibrium with hydrates at temperatures between (-55 and -10)°C and pressures between (3 and 120) bar, hence in both vapour and liquid phases. The experimental data are compared with predictions from two thermodynamic models: the Cubic-Plus-Association equation of state and an approach using Multi-Fluid Helmholtz Energy Approximation (MFHEA) equations of state (EoS). In all cases, the hydrate-forming conditions are modelled by the solid solution theory of van der Waals and Platteeuw.