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Study on Supercritical Fluids Thermodynamics Laboratory Dept. of Chemical Eng. National Taiwan University.

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Presentation on theme: "Study on Supercritical Fluids Thermodynamics Laboratory Dept. of Chemical Eng. National Taiwan University."— Presentation transcript:

1 Study on Supercritical Fluids Thermodynamics Laboratory Dept. of Chemical Eng. National Taiwan University

2 Correlation of Solid Solubility Equation of State (EOS) Method Activity Coefficient (G E ) Method Semi-empirical Correlation Equations Cluster Solvation Model

3 Solid – SCF Phase Equilibrium is calculated from an EOS

4 Equations of State Soave-Redlich-Kwong Complex Equation of SAFT Peng-Robinson Mixing Rules are the key point for an accurate calculation

5 Van der Waals Mixing Rules Binary interaction parameters are required (Ashour et al., Fluid Phase Equilibria,167,41,2000)

6 Disadvantages of EOS Method Binary interaction parameters can not be predicted or correlated Difficulty for extension to multi-component systems

7 Combinations of EOS and G E Models (Huron and Vidal, 1979) No adjustable parameter is required in this generalized method

8 Correlation of the volume correction parameters for non-polar solid compounds Correlation of the volume correction parameters for polar solid compounds

9 Calculation results for the solid solubilities for various fatty acids in supercritical carbon dioxide Predicted solubilities of phenanthrene (3) in CO 2 (1) - 2-naphthol (2) - phenanthrene (3) system

10 Comparison of Calculation Results

11 Application of the Solution Model  and  are empirical parameters

12 Relationship between the solid molar volume of caffeine in the supercritical phase and the pure solvent density. Relationship between the single parameter  of the solution model and the internal energy change of vaporization of the solute.

13 Comparison of the experimental and predicted solid solubility of penicillin G from the generalized correlation of solution model. Experimental data: ( ) 323.15 K; (  ) 333.15 K. Comparison of the experimental and calculated solid solubility of piroxicam from the solution model. Experimental data: ( ) 312.5 K; (  ) 331.5 K. Correlation results: (—) two- parameter method; (– –) one-parameter method.

14 Application of the Cluster Solvation Model Solvent, solute and solvent-Solute clusters are in chemical equilibrium at a high pressure condition Solid Solubility =

15 Calculation Results for Solid Solubility of Salicylic acid in Supercritical Carbon Dioxide with Cluster Solvation Model Calculation Results for the Solid Solubility of Phenanthrene in Supercritical Ethane with Cluster Solvation Model

16 Supercritical Extraction of Natural Compounds Nature Compound:  Semen Biotase A traditional chinese herb that can improve the sleep deprivation, digest system and diuretic problems.

17 Effect of temperature on the extraction yield of Semen Biotae at 20.7 MPa and 3.5 ml/min. ( ● 313.2 K ; ◆ 323.2 K ; ■ 333.2 K ; — calculated results from the modified Lack, s plug flow model ) Effect of temperature on the extraction yield of Semen Biotae at 34.5 MPa and 3.5 ml/min. ( ● 313.2 K ; ◆ 323.2 K ; ■ 333.2 K ; — calculated results from the modified Lack, s plug flow model )

18 Mathematical Models for Supercritical Fluid Extraction Plug Flow Model (Sovova 1994) Solvent flows axially with a superifical velocity U through a bed of materials in a cylinder extractor Local Adsorption Equilibrium Model Local adsorption equilibrium of solute between the solid and fluid phase


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