Measurements of phase equilibrium for systems containing oxygenated compounds.
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Date
2012
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Abstract
Accurate and reliable vapour-liquid equilibrium (VLE) and liquid-liquid equilibrium (LLE) data
are the key to a successful design and simulation of most important industrial separation
processes (traditional distillation, extractive and azeotropic distillation). This work focuses on
measurement of new phase equilibrium data for systems comprising of propan-1-ol, water and
diisopropyl ether which are of important use in the petrochemical industry. In addition, an
investigation of phase equilibrium behavior for systems of interest constituted by solvents and
high added-value oxygenated compounds deriving from lignocelluloses biomasses (bio-fuels)
was conducted at the Ecole des Mines de Paris CEP/TEP laboratories (France).Various data
bases such as Science Direct, ACS publications and Dortmund Data Bank (DDB, 2009) were
used to confirm that no literature data is available for these systems.
The VLE data measurements for the system of propan-1ol + water and propan-1ol + diisopropyl
ether (DIPE) ( 333.15, 353.15 and 373.15 K ) were carried out using a dynamic still of Lilwanth
(2011), with a test system (ethanol + cyclohexane at 40 kPa) undertaken prior measurements to
confirm the accuracy of the method and apparatus.The phase equilibrium (VLE and LLE)
behaviours for furan + n-hexane and furan + Methylbenzene, furfural + n-hexane and furan +
water were determined at 101.3 kPa. The atmospheric dynamic ebulliometry was used to
measure VLE systems at 101.3 kPa. A set of LLE data for furfural + n-hexane and furan + water
systems were obtained using a static analytical method, with a newly commissioned LLE
apparatus. Furfural + n-hexane system was compared used as test system, to verify the reliability
of the new equipment. The NRTL model was used to correlate the LLE data, with Cox-
Herington model used to predict the entire LLE curve for furfural+ n-hexane system. The
experimental VLE data were correlated using the combined y − y method. The vapour phase
non idealities were described using the methods from Nothnagel et al. (1973), Hayden and
O’Connell (1975) and the Peng-Robinson (1976) model. The activity coefficients were
correlated using the NRTL model of Renon and Prausnitz (1968) and the modified UNIQUAC
model of Abrams and Prausnitz (1976).
A propan-1-ol dehydration process was simulated using Aspen to illustrate the use and
importance of thermodynamic models in industrial process design and simulation. The model
used in the simulation was validated with measured VLE and literature LLE data.
Description
Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2012.
Keywords
Azeotropic distillation., Liquid-liquid equilibrium., Vapour-liquid equilibrium., Phase rule and equilibrium., Distillation., Theses--Chemical engineering.