Effect of Water Content on Thermodynamic Properties of Compressed Hydrogen

Abstract

Force field-based molecular simulations were used to calculate thermal expansivities, heat capacities, and Joule− Thomson coefficients of binary (standard) hydrogen−water mixtures for temperatures between 366.15 and 423.15 K and pressures between 50 and 1000 bar. The mole fraction of water in saturated hydrogen−water mixtures in the gas phase ranges from 0.004 to 0.138. The same properties were calculated for pure hydrogen at 323.15 K and pressures between 100 and 1000 bar. Simulations were performed using the TIP3P and a modified TIP4P force field for water and the Marx, Vrabec, Cracknell, Buch, and Hirschfelder force fields for hydrogen. The vapor−liquid equilibria of hydrogen−water mixtures were calculated along the melting line of ice Ih, corresponding to temperatures between 264.21 and 272.4 K, using the TIP3P force field for water and the Marx force field for hydrogen. In this temperature range, the solubilities and the chemical potentials of hydrogen and water were obtained. Based on the computed solubility data of hydrogen in water, the freezing-point depression of water was computed ranging from 264.21 to 272.4 K. The modified TIP4P and Marx force fields were used to improve the solubility calculations of hydrogen− water mixtures reported in our previous study et al. J. Chem. Eng. Data 2019, 64, 4103−4115] for temperatures between 323 and 423 K and pressures ranging from 100 to 1000 bar. The chemical potentials of ice Ih were calculated as a function of pressure between 100 and 1000 bar, along the melting line for temperatures between 264.21 and 272.4 K, using the IAPWS equation of state for ice Ih. We show that at low pressures, the presence of water has a large effect on the thermodynamic properties of compressed hydrogen. Our conclusions may have consequences for the energetics of a hydrogen refueling station using electrochemical hydrogen compressors.

Engineering Model for Predicting the Intradiffusion Coefficients of Hydrogen and Oxygen in Vapor, Liquid, and Supercritical Water based on Molecular Dynamics Simulations

“…For modeling H 2 , the single-site force fields developed by Buch, Vrabec and co-workers, and Hirschfelder et al, the two-site force field by Cracknell, and the modified three-site Silvera–Goldman by Alavi et al, and Marx and Nielaba force fields are tested (for brevity these force fields are referred to as Buch, Vrabec, Hirschfelder, Cracknell, Silvera–Goldman, and Marx hereafter). These H 2 force fields have been recently used in the literature to predict the thermophysical properties of H 2 O/H 2 mixtures in a wide range of temperatures and pressures. ,, Furthermore, the modified Silvera–Goldman force field has been used extensively in MD , and Monte Carlo − studies related to H 2 storage in clathrate hydrate structures. For additional information on the performance of the H 2 force fields for various mixtures, conditions, and properties, the reader is referred to the recent studies by Yang et al and Bartolomeu et al , For O 2 , the two-site force fields developed by Bohn et al., Miyano, and Coon et al, and the three-site models developed by Hansen et al, Vrabec et al, and Watanabe are used (for brevity these force fields are referred to as Bohn, Miyano, Coon, Hansen, Vrabec, and Watanabe hereafter).…”

Energy-efficient bioethanol recovery process using deep eutectic solvent as entrainer

“…The liquid compositions at equilibrium determined using molecular simulation were compared with the experimental results obtained in [13]. Although numerous studies [32,33,47] have implemented molecular simulations for establishing the thermodynamic and physical properties of various compounds, the reliability of the results is generally inadequate. In particular, process designs that necessitate large ( 5)…”

New Features of the Open Source Monte Carlo Software Brick-CFCMC: Thermodynamic Integration and Hybrid Trial Moves

“… 2 The CFCMC method considerably improves the insertion or deletion of molecules while allowing for a direct computation of chemical potentials and partial molar properties. 5 , 7 − 10 Brick-CFCMC has been used in many studies, especially for the computation of gas solubilities in solvents. 5 , 6 , 11 , 12 …”

“… 5 , 7 − 10 Brick-CFCMC has been used in many studies, especially for the computation of gas solubilities in solvents. 5 , 6 , 11 , 12 …”

“…5,7−10 Brick-CFCMC has been used in many studies, especially for the computation of gas solubilities in solvents. 5,6,11,12 We present the implementation of new features, namely, the computation of excess chemical potentials (μ ex ) using thermodynamic integration ( d…”