The isothermal flash problem. Part I. Stability

http://abollegend.persiangig.com/Theory_of_Gas_Injection_Processes_-_Franklin.pdf

Theory of Gas Injection Processes

The negative flash

This paper presents the predictions and calculations of the phase equilibria of oil, gas and water/brine mixtures where the oil and gas are modeled by a cubic equation of state and where the gas solubility in the aqueous phase is estimated from Henry's law. Henry's law constants for a variety of compounds of interest to the petroleum industry are correlated against pressure and temperature. The scaled-particle theory is used to take into account the presence of salt in the aqueous phase. An extensive match of experimental data is presented, showing the adequacy of the proposed model for Henry's law constant.

Phase equilibria of oil, gas and water/brine mixtures from a cubic equation of state and henry's law

Characterization of liquid−liquid equilibrium (LLE) in systems that contain ionic liquids (ILs) is important in evaluating ILs as candidates for replacing traditional extraction and separation solvents. Although an increasing amount of experimental LLE data is becoming available, comprehensive coverage of ternary liquid-phase behavior via experimental observation is impossible. Therefore, it is important to model the LLE of mixtures that contain ILs. Experimental binary and ternary LLE data that involve ILs can be correlated using standard excess Gibbs energy models. However, the predictive capability of these models in this context has not been widely studied. In this paper, we study the effectiveness with which excess Gibbs energy models can be used to predict ternary LLE solely from binary measurements. This is a stringent test of the suitability of various models for describing LLE in systems that contain ILs. Three different excess Gibbs free energy models are evaluated:  the non-random two-liquid (N...

/pdf/modeling-liquid-liquid-equilibrium-of-ionic-liquid-systems-7ak1lgouf9.pdf

Modeling Liquid−Liquid Equilibrium of Ionic Liquid Systems with NRTL, Electrolyte-NRTL, and UNIQUAC

For fluid systems that exhibit multiple phases, an equation of state may predict false phase equilibrium solutions. This paper presents a self-consistent method for determining whether a predicted equilibrium state is false. The method makes use of the equation of state to calculate the Gibbs energy surface and the tangent plane corresponding to the predicted equilibrium solution. If the tangent plane lies above the Gibbs energy surface at any point, the predicted equilibrium solution is false. Conversely, if the plane lies entirely below or tangent to the Gibbs energy surface, the solution does describe the equilibrium state.

K.D. Luks

Papers

Gibbs energy analysis of phase equilibria