Crossover SAFT equation of state: Application for normal alkanes

Journal Article · Wed Dec 01 04:00:00 EST 1999 · Industrial and Engineering Chemistry Research

DOI:https://doi.org/10.1021/ie990387i· OSTI ID:20005894

Kiselev, S B; Ely, J F

In this paper the authors develop a crossover modification of the statistical associating fluid theory (SAFT) equation of state for macromolecular chain fluids which incorporates the scaling laws asymptotically close to the critical point and is transformed into the original classical SAFT equation of state far away from the critical point. A comparison is made with experimental data for pure methane, ethane, n-hexane, n-decane, and n-eicosane in the one- and two-phase regions. The authors also present comparisons with experimental single-phase data for n-triacontane and n-tetracontane. They show that, over a wide range of states, the crossover SAFT model yields a much better representation of the thermodynamic properties of pure fluids than the original SAFT equation of state. The crossover SAFT equation of state reproduces the saturated pressure data in the entire temperature range from the triple point to the critical temperature with an average absolute deviation (AAD) of about 2.9% in the region bounded by 0.05{rho}{sub c} {le} {rho} {le} 2.5{rho}{sub c} and T{sub c} {le} T {le} 2T{sub c}, and the liquid density data with an AAD of about 3% at the pressures up to P = 2,000 bar. For the n-alkanes C{sub m}H{sub 2m+2} with the molecular weight M{sub w} {gt} 142 (m {gt} 10), the crossover SAFT model contains no adjustable parameters and can be used for the pure prediction of the fluid thermodynamic surface.

• Research Organization: Colorado School of Mines, Golden, CO (US)
• Sponsoring Organization: US Department of Energy
• DOE Contract Number: FG03-95ER14568
• OSTI ID: 20005894
• Journal Information: Industrial and Engineering Chemistry Research, Journal Name: Industrial and Engineering Chemistry Research Journal Issue: 12 Vol. 38; ISSN IECRED; ISSN 0888-5885
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
03 NATURAL GAS
ALKANES
DECANE
EQUATIONS OF STATE
ETHANE
HEXANE
MATHEMATICAL MODELS
METHANE
THERMODYNAMIC PROPERTIES