Phase equilibrium measurements and modelling for separation process design

Claudia Dell'Era

    Research output: ThesisDoctoral ThesisCollection of Articles


    The purpose of this research was to develop modelling of industrial processes by improving the thermodynamic representation of the equilibrium between phases. For this purpose an extensive experimental work was performed, comprising of vapour-liquid, gas-liquid and solid-liquid equilibrium measurements. Vapour liquid equilibrium of binary mixtures of butane + alcohols was measured with a static total pressure apparatus due to the importance of hydrocarbon and alcohol mixtures in the production of biofuels. The same equipment was used to measure binary systems of diethyl sulphide + C4 - hydrocarbons of importance in refinery applications. The activity coefficients of these systems were modelled with activity coefficients models. The absorption of carbon dioxide in alkanolamine solutions is the leading technology for the removal of carbon dioxide during refining of gas and oil. In recent years, this technology has gained importance also for carbon capture from large point sources. The scarcity of experimental data for some alkanolamine systems affected the accuracy of thermodynamic models. Several experimental techniques were developed to supply new experimental data for aqueous solutions of diisopropanolamine (DIPA) and methyldiethanolamine (MDEA). The solubility of carbon dioxide in solutions of these amines was measured with a static total pressure apparatus for gas solubility, and with a bubbling apparatus. The density of carbonated aqueous DIPA was also measured and modelled. The vapour-liquid equilibrium of water + DIPA and water + MDEA was measured with a static total pressure apparatus. The solid-liquid equilibrium of the same systems was measured with a visual method and a Differential Scanning Calorimeter. The activity coefficients of aqueous DIPA and MDEA solutions were modelled using NRTL, thus providing the first model of this sort for DIPA. A new model of the Henry's law constant of carbon dioxide in binary and ternary aqueous solutions of alkanolamines was developed at temperatures up to 393 K.
    Translated title of the contributionPhase equilibrium measurements and modelling for separation process design
    Original languageEnglish
    QualificationDoctor's degree
    Awarding Institution
    • Aalto University
    • Alopaeus, Ville, Supervising Professor
    • Aittamaa, Juhani, Thesis Advisor, External person
    Print ISBNs978-952-60-4518-4
    Electronic ISBNs978-952-60-4519-1
    Publication statusPublished - 2012
    MoE publication typeG5 Doctoral dissertation (article)


    • vapour-liquid equilibrium
    • solid-liquid equilibrium
    • solubility
    • carbon dioxide
    • diisopropanolamine
    • methyldiethanolamine
    • butane
    • diethyl sulphide
    • UNIFAC
    • COSMO
    • Henry's law
    • miniplant


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