The Fundamental Equation of State (FEOS) for SC-CO2 was developed by Span & Wagner (J. Phys. Chem. Ref. Data, 1996). The FEOS covers temperatures from CO2’s triple point (216.592 K) to 1100 K and pressures up to 800 MPa (8000 bar; 116000 psi).
The relative error between SCF CO2 PvT Properties App and Span and Wagner’s FEOS (using NIST’s Refprop v7) is consistently less than 0.001% except for a small region in which the difference increased to less than 0.005% (as seen in the Figure below). This difference is much less than the quoted accuracy of the FEOS.
The vapour pressure (reported for temperatures less than the critical temperature) is based on Equation 3.13 in Span & Wagner.
Available May 1, 2018…
SCF CO2 PvT Properties - Calculates carbon dioxide density and phase as a function of temperature and pressure based on Span and Wagner’s Fundamental Equation of State.
App Use Instructions / Information:
Temperature entry must only be in Kelvin. An “Out of Range” message is provided if a T less than the triple point or greater than 1100 K is entered. The vapour pressure of CO2 is also reported for temperatures less than the critical temperature.
Pressure may be entered in MPa, bar or psi. The conversion from bar to MPa is a division by 10 and from psi to MPa is multiplying by 0.00689476. An “Out of Range” message is provided if a P greater than 800 MPa is entered.