Equations of state for associating fluids (based on the analytic chain association theory)

In this work, we report a method for the application of equations of state for associating fluids using the analytic chain association theory (ACAT). ACAT has been extensively used in thermodynamic calculations of properties of associating fluids. However, its utility in the development of analytic equations of state for associating fluids is not well recognized. We have demonstrated that the ACAT can be incorporated in the equations of state without the need for any additional approximations other than what is already in the theory. Using certain mathematical manipulations and simplifications which were not recognized in the past, it is now possible to produce analytic equations of state for associating fluids. The resulting equations are still simple enough to be used for PVT and other property calculations. When this theory is applied to cubic equations of state, the cubic nature of these equations is retained. In order to demonstrate the applicability of the theory, numerical work for density and vapor pressure calculations are performed over wide ranges of temperature and pressure.