Methane hydrate phase equilibria for systems containing NaCl, KCl, and NH 4 Cl

Cha, Minjun; Hu, Yue; Sum, Amadeu K.

doi:10.1016/j.fluid.2015.08.010

Cited by 104 publications

(67 citation statements)

References 33 publications

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“…Equlibrium data shown in Figures 14 and 15 are precise (error bars corresponds to one standard uncertainty), within a maximum deviation of 0.7 K with respect to CSMGem [51] predictions, and comparable to previous studies [52][53][54]. Notwithstanding, prediction values are steadily higher for NaCl and consistently lower for MEG compared to our experiment.…”

Section: Systemsupporting

confidence: 90%

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A 3-In-1 Approach to Evaluate Gas Hydrate Inhibitors

2019

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With a single apparatus and very short experimentation times, we have assessed phase equilibria, apparent kinetics and morphology of methane gas hydrates in the presence of thermodynamic inhibitors ethane-1,2-diol (MEG) and sodium chloride (NaCl); and kinetic hydrate inhibitor polyvinyl-pyrrolidone (PVP). Tight, local temperature control produced highly repeatable crystal morphologies in constant temperature systems and in systems subject to fixed temperature gradients. Hydrate-Liquid-Vapor (HLV) equilibrium points were obtained with minimal temperature and pressure uncertainties (u T avg = 0.13 K and u p = 0.005 MPa). By applying a temperature gradient during hydrate formation, it was possible to study multiple subcoolings with a single experiment. Hydrate growth velocities were determined both under temperature gradients and under constant temperature growth. It was found that both NaCl and MEG act as kinetic inhibitors at the studied concentrations. Finally, insights on the mechanism of action of classical inhibitors are presented.

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Section: Systemsupporting

confidence: 90%

“…Error bars correspond to standard uncertainty. Literature data are also shown [54]. The curves show phase equilibria predictions using CSMGem [51].…”

Section: Systemmentioning

confidence: 99%

A 3-In-1 Approach to Evaluate Gas Hydrate Inhibitors

2019

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“…However, for salt-containing solutions, this isochoric method can be a very time-consuming process to determine the accurate hydrate phase equilibrium points, because the inhomogeneous distribution of the salinity in the system causes irregular hydrate dissociation and, therefore, a significantly longer time is required to reach an equilibrium state at each temperature ramping step. Several investigations have been conducted on less time-consuming, but accurate, techniques for determination of the hydrate phase equilibria in the presence of salts [34][35][36]. The DSC method has recently been introduced as a reliable and less time-consuming technique for hydrate equilibrium measurements [22,25,37].…”

Section: April 2016mentioning

confidence: 99%

Accurate measurement of phase equilibria and dissociation enthalpies of HFC-134a hydrates in the presence of NaCl for potential application in desalination

Lee

et al. 2016

Korean J. Chem. Eng.

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Phase equilibria, structure identification, and dissociation enthalpies of HFC-134a hydrates in the presence of NaCl are investigated for potential application in desalination. To verify the influence of NaCl on the thermodynamic hydrate stability of the HFC-134a hydrate, the three-phase (hydrate (H) -liquid water (L W ) -vapor (V)) equilibria of the HFC-134a+NaCl (0, 3.5, and 8.0 wt%)+water systems are measured by both a conventional isochoric (pVT) method and a stepwise differential scanning calorimeter (DSC) method. Both pVT and DSC methods demonstrate reliable and consistent hydrate phase equilibrium points of the HFC-134a hydrates in the presence of NaCl. The HFC134a hydrate is identified as sII via powder X-ray diffraction. The dissociation enthalpies (ΔH d ) of the HFC-134a hydrates in the presence of NaCl are also measured with a high pressure micro-differential scanning calorimeter. The salinity results in significant thermodynamic inhibition of the HFC-134a hydrates, whereas it has little effect on the dissociation enthalpy of the HFC-134a hydrates. The experimental results obtained in this study can be utilized as foundational data for the hydrate-based desalination process.

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“…This weakens hydrogen bonding interaction between water molecules, inhibiting the hydrate formation. 37,38 9…”

Section: Resultsmentioning

confidence: 99%

“…37,38 Hence, the charge density of Mg +2 is higher than Na + or K + . According to Sabil et al 37 and Cha et al 38 , the hydrate inhibiting strength rises in the following order: Mg +2 >Na + >K + . This agrees well with our observation in the presence of MgCl 2 (above 8%mass), MgCl 2 -NaCl , and MgCl 2 -NaCl-KCl.…”

Section: Resultsmentioning

confidence: 99%

Implementing Cyclopentane Hydrates Phase Equilibrium Data and Simulations in Brine Solutions

Ho-Van

Bouillot

Douzet

et al. 2018

Ind. Eng. Chem. Res.

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Cyclopentane hydrates-based salt removal is considered to be a possible promising technology for desalination. In order to optimize such processes, phase equilibrium data of Cyclopentane Hydrates (CPH) in saline solutions are crucial. Lamentably, these data sets are still incomplete.Therefore, earlier we published a limited experimental and modeling study on CPH equilibrium with some salts present.This study extends experimental equilibrium to four more common brine systems: Na 2 SO 4 , MgCl 2 , MgCl 2 -NaCl, or MgCl 2 -NaCl-KCl at various salt concentrations. Importantly, four thermodynamic approaches: the Standard Freezing Point Depression equation based (SFPD), Hu-Lee-Sum (HLS) correlation, and the two van der Waals and Platteuw-based Kihara and Activity-Based Occupancy Correlation (ABOC) methods, are compared to this new set of experimental data. Results show that simulations agree adequately with measured data. Nonetheless, the ABOC method is the best model to reproduce rapid and consistent equilibrium data of CPH in brine, whatever the electrolytes involved.

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Methane hydrate phase equilibria for systems containing NaCl, KCl, and NH 4 Cl

Cited by 104 publications

References 33 publications

A 3-In-1 Approach to Evaluate Gas Hydrate Inhibitors

A 3-In-1 Approach to Evaluate Gas Hydrate Inhibitors

Accurate measurement of phase equilibria and dissociation enthalpies of HFC-134a hydrates in the presence of NaCl for potential application in desalination

Implementing Cyclopentane Hydrates Phase Equilibrium Data and Simulations in Brine Solutions

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