Thermodynamic and kinetic hydrate inhibition performance of aqueous ethylene glycol solutions for natural gas

Cha, Minjun; Shin, Kyuchul; Kim, Juneyoung; Chang, Daejun; Seo, Yutaek; Lee, Huen; Kang, Seong-Pil

doi:10.1016/j.ces.2013.05.060

Cited by 134 publications

(87 citation statements)

References 22 publications

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“…Our results agree qualitatively with those reported previously for CO 2 hydrate growth rate in the presence of salt [56][57][58]: we observed reduced methane hydrate growth rates in the presence of NaCl. In contrast, Cha et al [6] reported that 10% MEG solution had no kinetic inhibition properties on natural gas hydrates, whereas we observed significant kinetic inhibition for methane hydrates with a 10% MEG solution. As expected [59][60][61], the hydrate film velocities in the presence of PVP are lower than those for pure water.…”

Section: Apparent Kineticscontrasting

confidence: 99%

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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: Apparent Kineticscontrasting

confidence: 99%

“…Cha et al [6] have reported that 10% MEG does not have kinetic inhibition properties whereas 30% MEG does have kinetic hydrate-inhibition properties. Although NaCl is considered to be a thermodynamic inhibitor, Chong et al [7] have noted its kinetic inhibition effects.…”

Section: Introductionmentioning

confidence: 99%

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

2019

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“…23,24 Thus, this promotion effect of THIs at low dosage appears common. It is reasonable to assume that salts, MEG, and methanol all thermodynamically inhibit hydrate formation (i.e., no "thermodynamic promotion"), so the observed promotion effect must be kinetic in nature.…”

Section: ■ Conclusion and Future Workmentioning

confidence: 95%

Formation of Ice, Tetrahydrofuran Hydrate, and Methane/Propane Mixed Gas Hydrates in Strong Monovalent Salt Solutions

et al. 2014

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Electrolytes can thermodynamically inhibit clathrate hydrate formation by lowering the activity of water in the surrounding liquid phase, causing the hydrates to form at lower temperatures and higher pressures compared to their formation in pure water. However, it has been reported that some thermodynamic hydrate inhibitors (THIs), when doped at low concentrations, could enhance the rate of gas hydrate formation. We here report a systematic study of model natural gas (a mixture of 90% methane and 10% propane) hydrate formation in strong monovalent salt solutions in a broad range of concentrations, using a high pressure automated lag time apparatus (HP-ALTA). HP-ALTA can apply a large number (>100) of cooling ramps to a sample and construct probability distributions of gas hydrate formation for each sample. The probabilistic interpretation of data enables us to mitigate the stochastic variation inherent in the nucleation probability distributions and facilitates meaningful comparison among different samples. The electrolytes used in this work are lithium chloride (LiCl), lithium bromide (LiBr), lithium iodide (LiI), sodium chloride (NaCl), sodium bromide (NaBr), sodium iodide (NaI), potassium chloride (KCl), potassium bromide (KBr), and potassium iodide (KI). We found that (1) some salts may act as kinetic hydrate promoters at low concentrations; (2) the width of the probability distributions (stochasticity) of natural gas hydrate formation in these salt solutions was significantly narrower than that in pure water. To gain further insight, we extended the study of the solutions of the same nine salts to the formation of ice and model tetrahydrofuran (THF) hydrate for comparison.

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“…However, usage of the THIs is not cost-effective and not practical in limited spaces such as ocean plants for loading or continuous supply of large quantities of the THIs because, to be effective, the THIs must be kept at high concentrations (10-40 wt%) [1,9,10]. 2 of 11 In this regard, kinetic hydrate inhibitors (KHIs) play an inhibition role at a lower dosage by retarding crystal formation and particle growth in ways that limit bulk [8][9][10][11]. Recently, KHIs were reported to cause anomalous hydrate dissociation inside the hydrate stability zone [12].…”

Section: Introductionmentioning

confidence: 99%

Anti-Agglomeration Effects of Biodegradable Surfactants from Natural Sources on Natural Gas Hydrate Formation

Kang

Lee

2020

Energies

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Kinetic hydrate inhibitors (KHI) and anti-agglomerants (AA) rather than thermodynamic hydrate inhibitors (THI) are often used for flow assurance in pipelines. This is because they require much lower dosages than thermodynamic inhibitors. Although the hydrate-phase equilibria are not affected, KHI and AA prevent the formed hydrate crystals from growing to a bulky state causing pipeline blockage. However, these KHIs might have huge environmental impact due to leakages from the pipelines. In this study, two biodegradable AA candidates from natural sources (that is, lecithin and lanolin) are proposed and their performances are evaluated by comparing them with and without a conventional AA (Span 80, sorbitan monooleate). At 30% and 50% water cut, the addition of AA materials was found to enhance the flow characteristics substantially in pipelines and hardly affected the maximum value of the rotational torque, respectively. Considering the cost-effective and environmental advantages of the suggested AA candidates over a conventional AA such as Span 80, the materials are thought to have potential viability for practical operation of oil and gas pipelines. However, additional investigations will be done to clarify the optimum amounts and the action mechanisms of the suggested AAs.

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Thermodynamic and kinetic hydrate inhibition performance of aqueous ethylene glycol solutions for natural gas

Cited by 134 publications

References 22 publications

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

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

Formation of Ice, Tetrahydrofuran Hydrate, and Methane/Propane Mixed Gas Hydrates in Strong Monovalent Salt Solutions

Anti-Agglomeration Effects of Biodegradable Surfactants from Natural Sources on Natural Gas Hydrate Formation

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