In this work, we present the modeling of the vapor-liquid-liquid equilibria (VLLE) for three ternary systems that are of interest in the natural gas and oil industry: nitrogen + methane + n-pentane, nitrogen + methane + n-hexane, and nitrogen + methane + n-heptane. The capabilities of the PC-SAFT and SRK equations of state to predict the complex phase behavior exhibited at low temperatures by the systems studied were compared and analyzed. The computer algorithm performing the isothermal multiphase flash calculations in the first case is based on the minimization of the Gibbs energy, while the second is based on the minimization of a modified tangent-plane distance function. The results obtained demonstrate that both equations of state predict with reasonable accuracy the experimentally observed phase behavior of the ternary systems considered.