Gas density estimates are of fundamental importance for process simulation, equipment design, and process safety engineering.  In the previous Tip of the Month (TOTM), two shortcut methods for predicting sour and acid gas density were evaluated. 
Due to the importance of CO₂ injection for enhanced oil recovery and the increasing interest in CO₂ capture and sequestration, this study was undertaken to evaluate the accuracy of density calculations for gases containing nil to 100% CO₂. An experimental data base was used for the basis of comparison.
Process simulation software often use equations of state for gas density calculations. Other sources of gas density calculation are NIST REFPROP (Reference Fluid Thermodynamic and Transport Properties) program and GERG-2004, a reference equation of state for natural gases. The study reviews all of these methods and will report their accuracies.
To learn more about this Tip and past Tips of the Month, visit JMC Tip of the Month.