Titel
Application of a Crossover Equation of State to Describe Phase Equilibrium and Critical Properties
Abstract
As the thermodynamic behavior of fluids near the critical points is extremely different from the critical behavior implied by classical equations of state, many attempts have been made to develop a crossover theory to bridge the gap between non-classical critical behavior asymptotically close to the critical point and classical behavior further away from the critical point.
Up to now, two main different approaches have been used to searching for a global equation for real fluids, in which the long-wavelength density fluctuations can be taken into account near the critical region:
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A renormalized Landau expansion; based on this method, Kiselev developed a phenomenological parametric crossover equation of state.
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The phase-space cell approximation method of White and collaborators.
The aim of this work is to develop a parametrization procedure for the crossover Soave-Redlich-Kwong equation of state using Kiselev’s approach. Since there is different sets of parameters (critical and crossover parameters), and one of the disadvantages of Kiselev’s procedure is several empirical system dependent parameters, it would be appropriate to investigate the sensibility of these parameters and their dependency on usual pure component properties to reduce the total number of fitted parameters.
Finally, we shall compare the results obtained with those of White’s recursive in the calculations of PvT-data, saturated and critical properties for n-alkanes (C1 to C10).