Determining the Three-phase Equilibrium Diagrams for Water, Oxygen, Propane and Lithium Using van der Waals Equations of State

摘要

In the present work, phase diagrams in (pressure, temperature) space were calculated for water, oxygen, propaneand lithium, employing van der Waals (vdW) equations of state, similar to an approach previously employed forargon. These calculations allowed the triple point temperatures to be obtained. The experimentally-determinedtriple point pressure values (p3) normalized by the critical point pressure (pc) (that is, p3/pc) are known toexhibit a significant correlation with the normalized triple point temperature (T3/Tc), and the present resultsreproduce this correlation qualitatively. This work also demonstrated that the low-density solid, high-densitysolid, liquid and gas-phases of water produce a phase diagram similar to that of the ice-water system.