Direct measurement of hydrate equilibrium temperature in CO₂ and CO₂ rich fluids with low water content

A high-pressure experimental setup was used to obtain experimental data on the hydrate equilibrium (melting) temperature (HET) of hydrates formed from low water content CO₂ and CO₂ rich mixtures. A novel method was used to measure hydrate formation temperature in addition to melting temperature directly at realistic temperature/pressure conditions encountered in transport by pipelines or ship. The method can be used to evaluate the likelihood of hydrate formation in pipelines/ships transporting pure CO₂ and CO₂ coming from capture processes as well as from high CO₂ content produced gas. The data generated from the measurement can also be used to investigate the kinetics of hydrate formation and dissociation in low water content fluids at pipeline/ship conditions. This paper details the experimental equipment, methods, test fluids and results. Experimental results are compared against predictions of the simplified cubic plus association equation of state (sCPA-EoS) coupled with the van der Waals and Platteeuw solid solution theory.