Isochoric phase stability testing for hydrocarbon mixtures

Dan Vladimir Nichita (1) , J.C. de Hemptinne (2) , S. Gomez (3)

1 TEFC - Thermodynamique et Energétique des fluides complexes
2 IFPEN - IFP Energies nouvelles
3 Instituto de Investigación en Matemática Aplicada y Sistemas

A method for global phase stability testing at isotherm-isochoric specifications has been developed. The formulation of the tangent plane distance (TPD) criterion in terms of the Helmholtz free energy density (calculated from a general two-parameter cubic equation of state) with component molar density as independent variables is used. An unconstrained minimization problem of a smooth function is solved using the tunneling global optimization method. Calculations are carried out for several representative mixtures; special attention is paid to the performance of the algorithm for near-critical conditions and the vicinities of phase boundaries. The test examples show the robustness and efficiency of the proposed method, and its high reliability in solving the isochoric phase stability problem.

Mots clés: Cubic equation of state; Global optimization; Isochoric conditions; Phase stability; Tangent plane distance; Tunneling

Domaines: Chimie-Physique [physics.chem-ph]

Dan Vladimir Nichita, J.C. de Hemptinne, S. Gomez. Isochoric phase stability testing for hydrocarbon mixtures. Petroleum Science and Technology, 2009, 27 (18), pp.2177-2191. ⟨10.1080/10916460802686681⟩. ⟨hal-00682538⟩