lib.PPR78 module

class lib.EoS.Cubic.PPR78.PPR78(T, P, mezcla, **kwargs)

Bases: PR78

Predictive Peng-Robinson cubic equation of state

\[\begin{split}\begin{array}[t]{l} P = \frac{RT}{V-b}-\frac{a}{V\left(V+b\right)+b\left(V-b\right)}\\ a = 0.45747\frac{R^2T_c^2}{P_c}\alpha\\ b = 0.0778\frac{RT_c}{P_c}\\ \alpha^{0.5} = 1 + m\left(1-Tr^{0.5}\right)\\ m = 0.37464 + 1.54226\omega-0.26992\omega^2 if \omega < 0.491\\ m = 0.379642 + 1.48503\omega - 0.164423*\omega^2 + 0.016666*\omega^3\\ k_{ij} = \frac{-\frac{1}{2}\sum_{k=1}^{Ng} \sum_{l=1}^{Ng} \left(\alpha_{ik}-\alpha_{jk}\right)\left(\alpha_{il}-\alpha_{jl}\right) A_{kl} \left(\frac{298.15}{T}\right)^{\left(\frac{B_{kl}}{A_{kl}}-1\right)} -\left(\frac{\sqrt{a_i}}{b_i}-\frac{\sqrt{a_j}}{b_j}\right)^2} {2\frac{\sqrt{a_i a_j}}{b_i b_j}} \end{array}\end{split}\]

Methods

mapUNIFAC()

Convert UNIFAC group saved in compound database to group contribution as used in PPR78

Examples

kij between propane and n-butane at T=303.15 from Appendix A of [1], tiny variation because differences in critical properties of components

>>> mix = Mezcla(5, ids=[4, 6], caudalMolar=1, fraccionMolar=[0.5, 0.5])
>>> eq = PPR78(303.15, 101325, mix)
>>> print("%0.4f" % self.kij[0][1])
0.0029

_Kij(eq=None)

Calculate binary interaction parameters

mapUNIFAC()

Convert UNIFAC group saved in compound database to group contribution as used in PPR78

References

[1]

Jaubert, J.-N., Mutelet, F.; VLE predictions with the Peng–Robinson equation of state and temperature dependent kij calculated through a group contribution method, Fluid Phase Equilibria 224 (2004) 285-304, http://dx.doi.org/10.1016/j.fluid.2004.06.059

[2]

Jaubert, J.-N., Vitu, S., Mutelet, F., Corriou, J.-P.; Extension of the PPR78 model (predictive 1978, Peng-Robinson EOS with temperature dependent kij calculated through a group contribution method) to systems containing aromatic compounds, Fluid Phase Equilibria 237 (2005) 193-211, http://dx.doi.org/10.1016/j.fluid.2005.09.003

[3]

Vitu, S., Jaubert, J.-N., Mutelet, F.; Extension of the PPR78 model (predictive 1978, Peng-Robinson EOS with temperature dependent kij calculated through a group contribution method) to systems containing naphtenic compounds, Fluid Phase Equilibria 243 (2006) 9-28, http://dx.doi.org/10.1016/j.fluid.2006.02.004