Analytically approximate solution to the VLE problem with the SRK
equation of state
In vapor liquid equilibrium (VLE) calculations with a cubic equation of
state (EoS), exact solution has to be carried out numerically with an
iterative approach [1,2]. This causes significant wastes of
repetitive efforts and computing resources. Based on a recent study
 on the van der Waals EoS [4,5], here we propose a procedure
for analytically approximate solutions to the VLE calculation with the
Soave-Redlich-Kwong (SRK) EoS  for the entire coexistence curve.
This procedure can be applied to any cubic EoS. A simple databank can be
built containing only the coefficients of a newly defined function and
other thermodynamic properties will be obtained with analytical forms.
For each system there is only a one-time effort. We also show that for
exact solutions, the VLE problem with any cubic EoS can be reduced to
solving a transcendental equation with one unknown, which can
significantly simplify the methods currently employed [2,7].