High-Pressure Fluid-Phase Equilibria and Henry's Constants of Supercritical Gases in Ammonia

Vapor-liquid equilibria of the binary mixtures argon-ammonia, methane-ammonia, hydrogen-ammonia, nitrogen-ammonia, and oxygen-ammonia are investigated by utilizing Monte Carlo and molecular dynamics simulations up to pressures of 100 MPa and beyond. At three different temperatures ranging from 233.15 to 377.59 K, the vapor pressure, densities of the saturated liquid and vapor, and enthalpy of vaporization are determined for each mixture as a function of molar composition. The Peng-Robinson and PC-SAFT equations of state are adjusted to combined simulation and experimental literature data. Included is a summary of the binary interaction parameters resulting from these fits. Henry's constant is also studied for each solute gas as a function of temperature over the range of 210.65 to 385.65 K. In total, over 2000 data points and their statistical uncertainties are provided, which show good agreement with experimental literature values. The estimated uncertainties in the data are regularly less than 5% and often much lower. Larger uncertainties occasionally occur at higher pressures. The database for ammonia mixtures is thereby significantly extended. Salient features of the data are identified and expounded upon.