Vapor-liquid equilibrium simulation of binary and ternary mixtures of CH₄, C₂H₄ and iso-C₄H₁₀

Abstract

The vapor-liquid equilibrium (VLE) properties for the binary and ternary mixtures of CH₄, C₂H₄ and iso-C₄H₁₀ are of great importance in the recovery of ethylene from mixture containing CH₄ and C₂H₄ with iso-C₄H₁₀ as solvent. Hence, Gibbs ensemble Monte Carlo (GEMC) simulations were used to estimate vapor-liquid equilibrium for the binary and ternary mixtures of CH₄, C₂H₄ and iso-C₄H₁₀ with the united atom potential NERD model. The selected simulation conditions are based on the experiment in the literature. The results of this work were shown to be in satisfactory agreement with available experimental data and predictions of Peng-Robinson equation of state. The structure of simulated liquid phase is also characterized by radial distribution function (RDF), which contributes to further understanding of the VLE curve of these systems. RDF is not sensitive to the pressure and temperature range. With the increase of pressure or the decrease of temperature, the molecules tend to gather together.

Keywords

Gibbs ensemble Monte Carlo / vapor-liquid equilibrium simulation / NERD / radial distribution function

References

[1] Zhang L H, Yan J, Jiang B, et al. Experimental study on ethylene recovery using the solvent absorption method[J]. Chemical Engineering & Technology, 2011, 34(8): 1353-1358.

[2] Peng D, Robinson D B. A new two-constant equation of state[J]. Industrial & Engineering Chemistry Fundamentals, 1976, 15(1): 59-64.

[3] Na P, Chen B, Wang Y, et al. Analysis and simulation of molecular dynamics of Lysozyme in water cluster system [J]. Transactions of Tianjin University, 2012, 18(1): 1-7.

[4] Do H, Wheatley R J, Hirst J D, et al. Gibbs ensemble Monte Carlo simulations of binary mixtures of methane, difluoromethane, and carbon dioxide[J]. The Journal of Physical Chemistry B, 2010, 114(11): 3879-3886.

[5] Spyriouni T, Economou I G, Theodorou D N, et al. Phase equilibria of mixtures containing chain molecules predicted through a novel simulation scheme[J]. Physical Review Letters, 1998, 80(20): 4466-4469.

[6] Lyubartsev A P, Martsinovski A A, Shevkunov S V, et al. New approach to Monte Carlo calculation of the free energy: Method of expanded ensembles[J]. The Journal of Chemical Physics, 1992, 96(3): 1776

[7] Panagiotopoulos A Z. Monte Carlo methods for phase equilibria of fluids[J]. Journal of Physics: Condensed Matter, 2000, 12(3): 25-52.

[8] Zhang Z, Duan Zhenhao. Phase equilibria of the system methane-ethane from temperature scaling Gibbs ensemble Monte Carlo simulation[J]. Geochimica et Cosmochimica Acta, 2002, 66(19): 3431-3439.

[9] Lago S, Garzon B, Calero S, et al. Accurate simulations of the vapor-liquid equilibrium of important organic solvents and other diatomics[J]. The Journal of Physical Chemistry B, 1997, 101(34): 6763-6771.

[10] Li Y, Yu Y, Zheng Y, et al. Vaporliquid equilibrium properties for confined binary mixtures involving CO₂, CH₄, and N₂ from Gibbs ensemble Monte Carlo simulations[J]. Science China Chemistry, 2012, 55(9): 1825-1831.

[11] Panagiotopoulos A Z. Direct determination of phase coexistence properties of fluids by Monte Carlo simulation in a new ensemble[J]. Molecular Physics, 1987, 61(4): 813-826.

[12] Panagiotopoulos A Z. Exact calculations of fluid-phase equilibria by Monte Carlo simulation in a new statistical ensemble[J]. International Journal of Thermophysics, 1989, 10(2): 447-457.

[13] Gubbins K E. Applications of molecular simulation[J]. Fluid Phase Equilibria, 1993, 83(1): 1-14.

[14] Moller D, Oprzynski J, Müller A, et al. Prediction of thermodynamic properties of fluid mixtures by molecular dynamics simulations: Methane-ethane[J]. Molecular Physics, 1992, 75(2): 363-378.

[15] Harris J G, Yung K H. Carbon dioxide’s liquid-vapor coexistence curve and critical properties as predicted by a simple molecular model[J]. The Journal of Physical Chemistry, 1995, 99(31): 12021-12024.

[16] Kristof T, Liszi J. Effective intermolecular potential for fluid hydrogen sulfide[J]. The Journal of Physical Chemistry B, 1997, 101(28): 5480-5483.

[17] Chen B, Martin M G, Siepmann J I, et al. Thermodynamic properties of the Williams, OPLS-AA, and MMFF94 all-atom force fields for normal alkanes[J]. The Journal of Physical Chemistry B, 1998, 102(14): 2578-2586.

[18] Carrion G G, Hasse H, Vrabec J, et al. Thermodynamic properties for applications in chemical industry via classical force fields[J]. Multiscale Molecular Methods in Applied Chemistry, 2012, 307(34): 201-249.

[19] Nath S K, Escobedo F, Fernando A, et al. On the simulation of vapor-liquid equilibria for alkanes[J]. The Journal of Chemical Physics, 1998, 108(23): 9905

[20] Martin M G, Siepmann J I. Novel configurational-bias Monte Carlo method for branched molecules. Transferable potentials for phase equilibria. 2. United-atom description of branched alkanes[J]. The Journal of Physical Chemistry B, 1999, 103(21): 4508-4517.

[21] Errington J R, Panagiotopoulos A Z. A new intermolecular potential model for the n-alkane homologous series[J]. The Journal of Physical Chemistry B, 1999, 103(30): 6314-6322.

[22] Ungerer P, Beauvais C, Delhommelle J, et al. Optimization of the anisotropic united atoms intermolecular potential for n-alkanes[J]. The Journal of Chemical Physics, 2000, 112(12): 5499

[23] Nath S K, Escobedo F A, Pablo J J, et al. Simulation of vapor-liquid equilibria for alkane mixtures[J]. Industrial & Engineering Chemistry Research, 1998, 37(8): 3195-3202.

[24] Nath S K, Pablo J D. Simulation of vapour-liquid equilibria for branched alkanes[J]. Molecular Physics, 2000, 98(4): 231-238.

[25] Nath S K, Khare R. New force field parameters for branched hydrocarbons[J]. The Journal of Chemical Physics, 2001, 115(23): 10837

[26] Wescott J T, Kung P, Nath S K. Vapour-liquid coexistence properties and critical points of two branched alkanes series[ J]. Fluid Phase Equilibria, 2003, 208(1): 123-139.

[27] Olds R H, Sage B H, Lacey W N, et al. Methane-isobutane system[J]. Industrial & Engineering Chemistry, 1942, 34(8): 1008-1013.

[28] His C, Benjamin C Y. Vapor-liquid equilibria in the methane-ethylene-ethane system[J]. The Canadian Journal of Chemical Engineering, 1971, 49(1): 140-143.

[29] Benedict M, Solomon E, Rubin L C, et al. Liquid-vapor equilibrium in methane-ethylene-isobutane system[J]. Industrial & Engineering Chemistry, 1945, 37(1): 55-59.

[30] Carvalho A P, Ramalho J P, Martins L F, et al. Excess thermodynamics of mixtures involving xenon and light linear alkanes by computer simulation[J]. The Journal of Physical Chemistry B, 2007, 111(23): 6437-6443.