Compressibility factor fugacity determination

Although only compressibility factor calculations are used as an example in the explanation of the method, other properties can be predicted equally well. Because of the temperature and density dependence of the diameters and shape factors needed to relate them to critical constants it is best to determine separate values of them for each component. Three basic dimensionless properties should be determined. These are the ones best suited to the use of the HSE method with an equation of state in terms of temperature and density. These are the compressibility factor, z the internal energy deviation (U — V)/RT and a dimensionless fugacity ratio, ln(f/pRT). All other desired properties can be obtained from them. The ln(f/pRT) and z are calculated similarly. The computation scheme is outlined as shown in Table III. 

---