Bubble Pressure Measurement and Modeling for n-Alkane + Aromatic Hydrocarbon Binary Mixtures

  • Author / Creator
    Liu, Qingchen
  • Commonly-used cubic equations of state (EOS) over predict the bubble point pressures (BPPs) for binary long-chain n-alkane + aromatic mixtures and frequently predict the incorrect phase diagram type. In this work, BPPs for 15 representative n-alkane + aromatic hydrocarbon binary mixtures were measured. The experimental results were compared with computed values obtained using the Peng-Robinson (PR) and Soave-Redlich-Kwong (SRK) EOS. For these cubic EOS, potential causes of the incorrect prediction of BPPs were studied. Binary interaction parameters (kij) for the PR and SRK EOS were regressed from experimental vapor-liquid equilibrium (VLE) data. It was found that negative kij values are required for cubic EOS in order to get accurate BPP predictions, contrary to the commonly-used positive or zero kij values for hydrocarbon mixtures. Regressed kijs trend towards larger negative values with increased size asymmetry of binary mixtures. Fitted kij values significantly improve the performance of PR and SRK EOS in predicting BPPs for highly asymmetric n-alkane + aromatic hydrocarbon binary mixtures. Experimental data were also used to validate other common thermodynamic models, including PC-SAFT, NRTL, UNIFAC and COSMO-SAC. These models were found to provide good BPP estimates for alkane + aromatic hydrocarbon mixtures without modification.

  • Subjects / Keywords
  • Graduation date
    Fall 2017
  • Type of Item
  • Degree
    Master of Science
  • DOI
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.