Phase equilibria analysis of the binary N2-NH3 and H2-NH3 systems and prediction of ternary phase equilibria

The high-pressure phase equilibria of binary mixtures, hydrogen-ammonia and nitrogen-ammonia, have been analyzed. A combined Chemical Association + Redlich–Kwong Equation of State (A + RKEOS) approach is adopted to represent gas-phase non-idealities while the liquid phase non-idealities are modeled using the NRTL equations. The proposed approach gave better representation as compared to other modified Redlich–Kwong Equations of State. The new approach was satisfactorily used to predict the phase equilibria of the ternary system of hydrogen–nitrogen–ammonia.