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Fawaz Hrahsheh Dr. Abdalla Obeidat Department of Physics JUST

Applying Gibbs theory on SAFT and PC-SAFT EOS’s to calculate nucleation rates of Ethanol and Methanol. Fawaz Hrahsheh Dr. Abdalla Obeidat Department of Physics JUST. EXTENSIONS OF SAFT & PC-SAFT. ● SAFT …Statistical Associating Fluid Theory. ● PC-SAFT …. Perturbed-Chain Statistical

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Fawaz Hrahsheh Dr. Abdalla Obeidat Department of Physics JUST

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  1. Applying Gibbs theory on SAFT and PC-SAFT EOS’s to calculate nucleation rates of Ethanol and Methanol. Fawaz Hrahsheh Dr. Abdalla Obeidat Department of Physics JUST

  2. EXTENSIONS OF SAFT & PC-SAFT ●SAFT…Statistical Associating Fluid Theory ● PC-SAFT….Perturbed-Chain Statistical Associating Fluid Theory

  3. SAFT and PC-SAFT EOS

  4. Outline ●Metastability and nucleation ● Temperature dependence of classical theories ● Conclusions

  5. Schematic pressure – temperature phase diagram for a pure substance SPINODAL LINE • Solid black lines represent points of equilibrium two-phase coexistence • c is the critical point • b is the triple point • When, say, gas is forced to cross lines ab or bc it is no longer the thermodynamically stable phase. • The transition to the new stable phase is not instantaneous.

  6. Metastable and unstable regions for the van der Waals fluid fluid critical point liquid gas spinodal binodal • The binodal curve (solid dome)separates one-phase and two-phase states • TC = critical temperature • The spinodal curve (dashed dome) separates metastable and unstable states • One true horizontal isotherm is shown • Adapted from Davis (1996)

  7. Classical nucleation rates are too low at low T; too high at high T.

  8. Classical nucleation rates are too low at low T; too high at high T.

  9. Three Versions of Classical Theory ●Gibbs’s exact formula: ● version 1: use bulk surface tension for ● Version 2: liquid droplet is incompressible, • and ● Version 3: the vapor is an ideal gas • and • S =Pv /Pve (Supersaturation)

  10. Pressure vs density isotherm

  11. Nucleation rate is given by where

  12. Gibbs’s formula improves classical nucleation rates for H2O based on IAPWS-95.

  13. Conclusions • Pressure version of W resulted in improvements over the other versions for H2O. • The first version of classical theory with exact EOS’s used to predict the T dependence.

  14. Thank You

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