The Improved Grayson-Streed (IGS) method is an extension of the Grayson-Streed method to support a rigorous three phase calculation for hydrocarbon systems with an aqueous phase. The liquid fugacity curves for N2, H2S, H2O, CO, CO2 and O2 were also improved from the original work.
See "Improved Grayson-Streed (IGS)" under "Generalized Correlation Methods" in Chapter 2, Volume 1 of the PRO/II Reference Manual for more information.
Application Guidelines
Same as Grayson-Streed. Can also be used for rigorous calculations involving three phase hydrocarbon systems where one liquid phase is aqueous.