The Z-factor
Z(p, T) correlations for fluid mixtures provide fast computational procedures using the fluid mixture properties rather than multi-component procedures of Equation of State.
These correlations are usually modelled through the pseudo-reduced fluid properties
(T_{pr}, P_{pr}):
T_{pr} = T/T_{pc} | Pseudo-reduced temperature | T_{pc} | Pseudo-critical temperature |
P_{pr} = P/P_{pc} | Pseudo-reduced pressure | P_{pc} | Pseudo-critical pressure |
Charts
Implicit Correlations
These correlations are quite accurate and work in a wide range of pressures and temperatures but computationally expensive and may have problems with convergence when approaching the critical temperature.
Hall and Yarborough’s Z-factor correlation @model Dranchuk, Purvis and Robinson’s Correlation (Dranchuket al. 1971) Dranchuk and Abou-Kassem’s correlation (Abou-kassemand Dranchuk 1975) |
Explicit Correlations
The explicit correlations do not have convergence issues, generate smooth derivatives for compressibility calculations and provide fast computing.
Kareem Z-factor Correlation @model (2016) Sanjari and Nemati’s Correlation (2012) Azizi, Behbahani and Isazadeh’s Correlation (2010) Heidaryan, Moghdasi and Rahimi’s Correlation (2010) |
See also
Natural Science / Physics /Thermodynamics / Equation of State / Z-factor