High pressure multi-component vapor-liquid equilibrium data and model predictions for the LNG industry

Thomas J. Hughes, Jerry Y. Guo, Corey J. Baker, Darren Rowland, Brendan F. Graham, Kenneth N. Marsh, Stanley H. Huang, Eric F. May

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5 Citations (Scopus)

Abstract

Accurate simulations of scrub columns in liquefied natural gas (LNG) plants are challenging, requiring frequent solution of the non-linear equations governing vapor-liquid equilibrium (VLE), material, and energy balances for multi-component mixtures. Reliable fluid property predictions at high pressures and low temperatures are thus crucial; however, no high-quality multi-component VLE data at conditions relevant to the LNG scrub column are available to test commonly-used equations of state (EOS). Here we report VLE measurements at pressures to 9 MPa and temperatures from (203 to 273) K for mixtures containing CH4, C2H6, C3H8, iC4H10, nC4H10 and/or N2. Far from the mixture's critical point, the GERG-2008 EOS predictions were more accurate than the Peng-Robinson EOS predictions. Above 7 MPa both EOS under-predicted the liquid phase's methane content and over-predicted its butane content by 10–50 times the experimental uncertainty. Rowland et al.'s recent revision of the GERG model reduced the maximum deviations by (17–35)%. Further optimizations should improve the constituent binary departure functions and hence improve the description of multicomponent VLE data, particularly at conditions relevant to LNG production.

Original languageEnglish
Pages (from-to)81-90
Number of pages10
JournalThe Journal of Chemical Thermodynamics
Volume113
DOIs
Publication statusPublished - 1 Jan 2017
Externally publishedYes

Keywords

  • Distillation
  • Gas purification
  • LNG
  • Natural gas
  • Phase equilibrium

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