Convergence of the Continuous Fluid−Solid Phase Equilibrium Problem Using Quadrature Compositional Characterizations

Abstract

The solid−fluid phase equilibrium problem is solved for an n-paraffinic C7+ model fluid whose pseudocomponent compositional characterization is determined by finite Laguerre−Gauss quadrature, under the assumption that the initial solid phase formed is a “pure” pseudocomponent. Of interest is how rapidly the crystal point temperature result converges with an increase in the level of quadrature. It is concluded that the highly nonlinear nature of the fluid phase's Gibbs energy of mixing presents a serious challenge to obtaining a satisfactory asymptotic result. Furthermore, it is suggested that the convergence of fluid-phase equilibrium results with increasing quadrature level may likewise be affected, though probably to a lesser extent.