As always, it was a great class at ChEPS! I totally enjoyed the 11 days with the clever and motivated students. As before, the last day of the course (Saturday) featured individual presentations by all participants. Please find the topics below the pictures 🙂

My tutor this time was Ittisak Promma, who did a great job. I couldn’t have done this without him!

And special thanks to the director, Prof Hong-ming Ku, who gave me the chance to teach at his school.

#### Presentations

- Explain the Joule-Thompson inversion curve and its practical significance. Calculate the curve for methane using the Soave-Redlich-Kwong equation (Aspen Plus and/or Mathcad) and compare to experimental data.
- Compare the calculation of enthalpy changes of fluids using the equation of state and latent heat approach.
- Discuss different methods for the experimental determination of pure component vapor pressures.
- Explain the chemical theory for vapor dimerization of carboxylic acids and how to use in in the calculation of the VLE of mixtures.
- Compare the experimental data for HF vapor heat capacity at different pressures, heat of vaporization and liquid heat capacity from the DDB to the results of the NRTL-HF model in Aspen Plus. Explain the model and discuss the results. Could you improve the model?
- Explain the dependence of the K-factor for liquid-liquid extraction in the system water – acetic acid – benzene on acetic acid concentration. How would you concentrate acetic acid at concentrations lower than 10 mol% in water?
- Calculate the separation factor α at the mean normal boiling temperature of two non-polar components with a boiling temperature difference of 15°C, for different boiling temperatures of the light boiler (170K to 500K). Estimate the heat of vaporization using the Pictet-Trouton rule and treat the vapor phase as ideal and neglect the liquid volume. Discuss the result.
- The mixture anthracene – phenanthrene cannot be separated by ordinary distillation. Discuss other options including the use of the difference in sublimation pressure.
- Explain the measurement of activity coefficients at infinite dilution using gas chromatographic retention times.
- Explain the derivation of the UNIQUAC g
^{E}-model.

(p. 347 ff in Prausnitz J. M., Lichtenthaler R. N. & de Azevedo E. G. – Molecular Thermodynamics of Fluid-Phase Equilibria) - Show how to verifying g
^{E}-model BIPs in Aspen Plus using data from TDE and the DDB. - Extend the Antoine equation by a term to describe also the solid vapor pressure and regress the data of Bilde et al. (see cloud) using C=-Tb/8. (Mathcad or Excel)
- What are the cryoscopic and ebullioscopic constants and their practical importance? Calculate the constants for benzene and water. Why is the polarity of the solute of no importance?
- Calculate the solubility of sucrose in water from room temperature to the melting temperature with and without taking into account the difference in solid and liquid heat capacity. Assume ideal mixture behavior. Calculate the activity coefficient of sucrose along the solubility curve from experimental solubility data. (parameters and data see A.M. Peres, E.A. Macedo, Fluid Phase Equilib. 123 (1996), p. 71-95)
- Explain the VLE calculation using EOS (quadratic mixing rule) for the mixture N2-CH4
- Calculate the activity coefficient of water in n-alcohols at 25°C (UNIFAC, mod. UNIFAC) and compare to experiment (DDB). Can you explain the trend from molecular properties?
- Explain the regression of NRTL BIPs from experimental VLE data. Discuss possible choices for the objective function.
- Explain in detail how to calculate the activity coefficient in the mixture ethanol – water at 70 °C and x
_{1}= 0.252 using original UNIFAC. - Explain the mutual salting out effect of NaCl and KCl in water. Calculate the solubility limit as function of NaCl and KCl molality in Aspen Plus.
- Explain the idea of NRTL-SAC and how to calculate the VLE of a binary mixture.
- Residual curve plots – solvent selection for azeotropic distillation.
- Explain the Kalina cycle.
- Explain the Sulphur-Iodine cycle for hydrogen production.
- In the QVF-process, acetic acid is first extracted from aqueous solution using e.g. MIBK. The process achieves high concentrations of acetic acid, which also increases the water content. Explain, how the liquid sidedraw in the azeotrope-column allows such high water content. Asume a feed of 20 mol% of acetic acid in the water feed.