Table 6 Methods used to calculate the compressibility factor Z in the literature.

Loebenstein⁴⁶

\(z=1+\frac{p_{pr}}{A_1T_{pr}}\left[A_2 \frac{1}{T_{pr}}\left(\frac{1}{T_{pr}}+1\right)-1\right]\)

Mahmoud⁴⁷

\(Z=A_1-A_2p_{pr}-\frac{A_3}{T_{pr}}+A_4 p_{pr}^{2}+\frac{A_5}{T_{pr}}+A_6\frac{p_{pr}}{T_{pr}}\)

H−S−M method⁴⁸

\(Z=\frac{A_1+A_2 ln p_{pr}+A_3 (ln p_{pr})^{2}+A_4 (ln p_{pr})^{3}+\frac{A_5}{T_{pr}}+\frac{A_6}{T^{2}_{pr}}}{1+A_7 ln p_{pr}+A_8 (ln p_{pr})^{2}+\frac{A_9}{T_{pr}}+\frac{A_{10}}{T^{2}_{pr}}}\)