Methane–Propane Mixed Gas Hydrate Film Growth on the Surface of Water and Luvicap EG Solutions

Wu, Reuben; Kozielski, Karen; Hartley, Patrick G.; May, Eric F.; Boxall, J.; Maeda, Nobuyo

doi:10.1021/ef4003268

Cited by 34 publications

(32 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The hydrate film was very thin (based on translucency) and smooth compared to hydrates formed from pure water [25] or in the presence of MEG ( Figure 4) and NaCl (Figure 9). This result is comparable with those reported in past studies for KHIs [14,39,40]. Addition of KHIs has been postulated to increase the porosity of the hydrate crust, thus allowing for guest transport and thickening of the clathrate [41][42][43][44][45][46].…”

Section: Water + Ch 4 + Meg (W Meg = 10%)supporting

confidence: 91%

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

2019

View full text Add to dashboard Cite

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.

show abstract

Section: Water + Ch 4 + Meg (W Meg = 10%)supporting

confidence: 91%

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

2019

View full text Add to dashboard Cite

show abstract

“…This mechanism was proposed by Wu et al to explain inhibition in the presence of KHIs such as Luvicap EG. They suggested 48 that the KHIs molecules bind to the hydrate surface and prevent growth. Ions might behave like KHIs (1) by disrupting the local hydrogen bonding network of water and the interaction with the guest molecules, which may in turn prevent nucleation, and (2) by adsorbing to the surface of hydrate crystals which inhibit the access of water and gas molecules to the growth front.…”

Section: ■ Discussionmentioning

confidence: 99%

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

et al. 2014

Self Cite

View full text Add to dashboard Cite

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.

show abstract

“…In other applications such as oil and gas transport through pipelines, hydrate formation and growth must be impeded to ensure flow, which is achieved by using low dosage (a few hundreds to thousands of ppm) water soluble molecules called kinetic hydrate inhibitors (KHIs). The performance of these KHIs might be related to their ability to slow down the lateral growth of the hydrate crust at the water/guest interface where they usually adsorb (Peng et al, 2009;Duchateau et al, 2012;Wu et al, 2013); another important factor seems to be the localization of hydrate growth at the interface, which impedes or delays the growth of a 3D porous structure by the capillary driven flow mechanism mentioned above.…”

Section: Introductionmentioning

confidence: 99%

“…The studies conducted with surfactant or polymeric addi tives present in the water phase are of two sorts. One is concerned with polymeric additives inhibiting hydrate formation (KHIs), which delay nucleation and/or slow down hydrate film lateral growth at water/guest interfaces (Peng et al, 2009;Duchateau et al, 2012;Wu et al, 2013). The other is concerned with additives (such as SDS) promoting hydrate formation.…”

Section: Introductionmentioning

confidence: 99%

Hydrate growth at the interface between water and pure or mixed CO2/CH4 gases: Influence of pressure, temperature, gas composition and water-soluble surfactants

Daniel‐David

Guerton

Dicharry

et al. 2015

Chemical Engineering Science

View full text Add to dashboard Cite

International audienceThe morphology and growth of gas hydrate at the interface between an aqueous solution and gaseous mixtures of CO2 and CH4 are observed by means of a simple experimental procedure, in which hydrate formation is triggered at the top of a sessile water drop by contact with another piece of gas hydrate and the ensuing hydrate growth is video-monitored. The aqueous solution is either pure water or a solution of a nonionic or anionic surfactant at low concentration (in the 100-1000ppmw range). In agreement with previously published data, hydrates formed from pure water and aqueous solutions of non-ionic surfactant grow rapidly as a low-permeable polycrystalline crust along the water/gas interface, which then inhibits further growth in a direction perpendicular to the interface. Lateral growth rates increase strongly with subcooling and CO2 content in the gas mixture. Similar lateral growth rates, but varying morphologies, are observed with the non-ionic surfactants tested. In contrast, the two anionic surfactants tested, sodium dodecyl sulfate (SDS) and dioctyl sodium sulfosuccinate (AOT), promote in the presence of CH4 (but not in the presence of CO2) a rapid and full conversion of the water drop into hydrate through a 'capillary-driven' growth process. Insights are given into this process, which is observed with AOT for an unprecedented low concentration of 100ppmw

show abstract

Methane–Propane Mixed Gas Hydrate Film Growth on the Surface of Water and Luvicap EG Solutions

Cited by 34 publications

References 25 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

Hydrate growth at the interface between water and pure or mixed CO2/CH4 gases: Influence of pressure, temperature, gas composition and water-soluble surfactants

Contact Info

Product

Resources

About