Z-factor Correlations @model

The Z-factor $\begin{array}{l}Z(p, T)\end{array}$ 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 $\begin{array}{l}(T_{pr}, P_{pr})\end{array}$ :

$\begin{array}{l}T_{pr} = T/T_{pc}\end{array}$	Pseudo-reduced temperature	$\begin{array}{l}T_{pc}\end{array}$	Pseudo-critical temperature
$\begin{array}{l}P_{pr} = P/P_{pc}\end{array}$	Pseudo-reduced pressure	$\begin{array}{l}P_{pc}\end{array}$	Pseudo-critical pressure

Charts

Standing-Katz Z-factor correlation chart

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)

Brill & Beggs Z-factor Correlation @model (1973)

Page tree

Z-factor Correlations @model

Implicit Correlations

Explicit Correlations