CO2 fugacity

 

For accurate calculations, the fugacity of CO2, fCO2, may be used instead of its partial pressure. The fugacity can be calculated from its partial pressure (Koerzinger, 1999).

The calculation for this gas requires two virial coefficients B and d , as explained here as follows (from Zeebe 2001)

Here are the related lines of code :

fCO2 = ppmCO2*exp(101325*((-1636.75 + 12.0408*T - 3.27957e-2*T^2 + 3.16528e-5*T^3)*1e-6 +         + 2*(57.7 - 0.118*T)*1e-6)/R/T)
H2CO3 = K0*fCO2*1e-6