Lennard-Jones (L-J) and Buckingham exponential-6 (exp-6) potential models were used
to produce isotherms for methane at temperatures below and above critical one.
Molecular simulation approach, particularly Monte Carlo simulations, were employed to
create these isotherms working with both canonical and Gibbs ensembles. Experiments
in canonical ensemble with each model were conducted to estimate pressures at a
range of temperatures above methane critical temperature. Results were collected and
compared to experimental data existing in literature; both models showed an elegant
agreement with the experimental data. In parallel, experiments below critical
temperature were run in Gibbs ensemble using L-J model only. Upon comparing results
with experimental ones, a good fit was obtained with small deviations. The work was
further developed by adding some statistical studies in order to achieve better
understanding and interpretation to the estimated quantities by the simulation.
Methane phase diagrams were successfully reproduced by an efficient molecular
simulation technique with different potential models. This relatively simple
demonstration shows how powerful molecular simulation methods could be, hence
further applications on more complicated systems are considered. Prediction of phase behavior of elemental sulfur in sour natural gases has been an interesting and
challenging field in oil and gas industry. Determination of elemental sulfur solubility
conditions helps avoiding all kinds of problems caused by its dissolution in gas
production and transportation processes. For this purpose, further enhancement to the
methods used is to be considered in order to successfully simulate elemental sulfur
phase behavior in sour natural gases mixtures.
| Date of Award | Jun 6 2011 |
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| Original language | English (US) |
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| Awarding Institution | - Physical Sciences and Engineering
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| Supervisor | Shuyu Sun (Supervisor) |
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