  Understanding fluid phase behavior in high pressure and high temperature
conditions is crucial for developing high-fidelity simulations of chemically
reacting flows in liquid-fueled combustion systems. The study of vapor-liquid
equilibrium (VLE) curves also forms an integral part of the design and modeling
of the control processes in chemical and oil-gas industries. The main objective
of this study was to develop data-driven models to predict VLE of Type III
binary mixtures involving long-chained n-alkanes and nitrogen. Two data-driven
models have been proposed in this study, each of which was competent in
estimating VLE for the binary systems of C10/N2 and C12/N2, at pressures
ranging up to 50-60 MPa. Both the models showed better performance (less
average absolute percentage error) in predicting equilibrium pressure of the
binary mixtures as compared to the VLE modeled using Peng-Robinson equation of
state (PR-EOS). The data-driven models were also able to correctly trace the
change in curvature of the vapor phase composition, close to the mixture
critical point, at high pressures and temperatures-a feature of the
n-alkane/nitrogen system VLE which the PR-EOS model fails to capture.
