Review of Experimental Data and Evaluation of Equations of State for Modeling Formation of Solid CO ₂ in CCS and Natural Gas Applications

Solid CO2 is a potential safety hazard in many applications. Freeze-out can be predicted by combining the equations of state (EoS) for the fluid and solid phases. We have reviewed available equilibrium data for mixtures relevant for carbon capture, transport, and storage (CCS) and natural gas applications and performed a comprehensive assessment of model combinations. The most significant difference in model accuracy came from the choice of fluid EoS. For CCS applications, the best agreement with experimental data was achieved by using the Peng–Robinson EoS, yielding a Mean Absolute Percentage Deviation (MAPD) of 1.4%. For natural gas applications, the most updated multiparameter EoS was the most accurate choice, yielding a MAPD below 1%. Provided that an accurate EoS for the solid phase is available, including solid data in the regression of the fluid EoS represents an avenue that can be exploited to achieve more accurate solid-phase predictions in the future.