Molecular simulation of thermodynamic and transport properties for the H2O+NaCl system

2014 ◽  
Vol 141 (23) ◽  
pp. 234507 ◽  
Author(s):  
Gustavo A. Orozco ◽  
Othonas A. Moultos ◽  
Hao Jiang ◽  
Ioannis G. Economou ◽  
Athanassios Z. Panagiotopoulos
Keyword(s):  
Transport Properties ◽  
Molecular Simulation ◽  
Thermodynamic And Transport Properties

An Estimation of Thermodynamic and Transport Properties of Cryogenic Hydrogen Using Classical Molecular Simulation

2011 ◽  
Author(s):  
Hiroki Nagashima ◽  
Takashi Tokumasu ◽  
Shin-ichi Tsuda ◽  
Nobuyuki Tsuboi ◽  
Mitsuo Koshi ◽  
...  
Keyword(s):  
Ab Initio ◽  
Transport Properties ◽  
Molecular Simulation ◽  
Potential Model ◽  
Classical Method ◽  
Quantum Effect ◽  
Corresponding States ◽  
Density Region ◽  
Lennard Jones ◽  
Thermodynamic And Transport Properties

In this paper, we estimated the thermodynamic and transport properties of cryogenic hydrogen using classical molecular simulation to clarify the limit of classical method on the estimation of those properties of cryogenic hydrogen. Three empirical potentials, the Lennard-Jones (LJ) potential, two-center Lennard-Jones (2CLJ) potential, and modified Buckingham (exp-6) potential, and an ab initio potential model derived by the molecular orbital (MO) calculation were applied. Molecular dynamics (MD) simulations were performed across a wide density-temperature range. Using these data, the equation of state (EOS) was obtained by Kataoka’s method, and these were compared with NIST (National Institute of Standards and Technology) data according to the principle of corresponding states. Moreover, we investigated transport coefficients (viscosity coefficient, diffusion coefficient and thermal conductivity) using time correlation function. As a result, it was confirmed that the potential model has a large effect on the estimated thermodynamic and transport properties of cryogenic hydrogen. On the other hand, from the viewpoint of the principle of corresponding states, we obtained the same results from the empirical potential models as from the ab initio potential, showing that the potential model has only a small effect on the reduced EOS: the classical MD results could not reproduce the NIST data in the high-density region. This difference is thought to arise from the quantum effect in actual liquid hydrogen.

Molecular simulation of structure, thermodynamic and transport properties of polymeric membrane materials for hydrocarbon separation

2005 ◽  
Vol 228-229 ◽  
pp. 15-20 ◽  
Author(s):  
Ioannis G. Economou ◽  
Vasilios E. Raptis ◽  
Vasilios S. Melissas ◽  
Doros N. Theodorou ◽  
John Petrou ◽  
...  
Keyword(s):  
Transport Properties ◽  
Molecular Simulation ◽  
Polymeric Membrane ◽  
Membrane Materials ◽  
Thermodynamic And Transport Properties

Thermodynamic and transport properties of carbon dioxide from molecular simulation

2007 ◽  
Vol 126 (6) ◽  
pp. 064509 ◽  
Author(s):  
Carlos Nieto-Draghi ◽  
Theodorus de Bruin ◽  
Javier Pérez-Pellitero ◽  
Josep Bonet Avalos ◽  
Allan D. Mackie
Keyword(s):  
Carbon Dioxide ◽  
Transport Properties ◽  
Molecular Simulation ◽  
Thermodynamic And Transport Properties

scholarly journals A Molecular Simulation Study of Silica/Polysulfone Mixed Matrix Membrane for Mixed Gas Separation

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2199
Author(s):  
Khadija Asif ◽  
Serene Sow Mun Lock ◽  
Syed Ali Ammar Taqvi ◽  
Norwahyu Jusoh ◽  
Chung Loong Yiin ◽  
...  
Keyword(s):  
Transport Properties ◽  
Molecular Simulation ◽  
Gas Separation ◽  
Membrane Separation ◽  
Gas Transport ◽  
Mixed Matrix ◽  
Mixed Gas ◽  
Gas Transport Properties ◽  
Simulation Results ◽  
Mixed Gases

Polysulfone-based mixed matrix membranes (MMMs) incorporated with silica nanoparticles are a new generation material under ongoing research and development for gas separation. However, the attributes of a better-performing MMM cannot be precisely studied under experimental conditions. Thus, it requires an atomistic scale study to elucidate the separation performance of silica/polysulfone MMMs. As most of the research work and empirical models for gas transport properties have been limited to pure gas, a computational framework for molecular simulation is required to study the mixed gas transport properties in silica/polysulfone MMMs to reflect real membrane separation. In this work, Monte Carlo (MC) and molecular dynamics (MD) simulations were employed to study the solubility and diffusivity of CO2/CH4 with varying gas concentrations (i.e., 30% CO2/CH4, 50% CO2/CH4, and 70% CO2/CH4) and silica content (i.e., 15–30 wt.%). The accuracy of the simulated structures was validated with published literature, followed by the study of the gas transport properties at 308.15 K and 1 atm. Simulation results concluded an increase in the free volume with an increasing weight percentage of silica. It was also found that pure gas consistently exhibited higher gas transport properties when compared to mixed gas conditions. The results also showed a competitive gas transport performance for mixed gases, which is more apparent when CO2 increases. In this context, an increment in the permeation was observed for mixed gas with increasing gas concentrations (i.e., 70% CO2/CH4 > 50% CO2/CH4 > 30% CO2/CH4). The diffusivity, solubility, and permeability of the mixed gases were consistently increasing until 25 wt.%, followed by a decrease for 30 wt.% of silica. An empirical model based on a parallel resistance approach was developed by incorporating mathematical formulations for solubility and permeability. The model results were compared with simulation results to quantify the effect of mixed gas transport, which showed an 18% and 15% percentage error for the permeability and solubility, respectively, in comparison to the simulation data. This study provides a basis for future understanding of MMMs using molecular simulations and modeling techniques for mixed gas conditions that demonstrate real membrane separation.

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