Rheology of methane hydrate slurries formed from water-in-oil emulsion with different surfactants concentrations

Liu, Zaixing; Song, Yongchen; Liu, Weiguo; Liu, Ran; Chen, Lang; Li, Yanghui

doi:10.1016/j.fuel.2020.117961

Cited by 47 publications

(27 citation statements)

References 48 publications

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“…The water conversion fraction was 1.7% at 596 min, and the hydrate formation rate R a was 3.52 × 10 –4 mole of methane/mol of water/h. During this period, due to the small amount of hydrate formed, the shearing action of the rotor caused the breaking and recombining of hydrate particles and distributed the hydrate particles evenly in the hydrate slurry, which kept the viscosity basically unchanged . From 596 to 973 min, the water conversion fraction increased from 1.7% to 2.8%, and the viscosity of fluctuation of the slurry increased to 17 Pa·s.…”

Section: Results and Discussionmentioning

confidence: 99%

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Rheological Properties of Hydrate Slurry Formed from Mudflows in South China Sea

Liu

Zhang

et al. 2021

Energy Fuels

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Solid fluidization is a current promising method to explore hydrate resources. The rheological properties of hydrate slurry are significant to solid fluidization and prevent hydrate blockage during pipeline transportation. To determine the impact of hydrate on the rheological properties of mudflow, a rheological experiment was conducted on methane hydrate slurry formed from a mudflow, which was prepared with marine sediment sampled from South China Sea. It was found that both mudflow and hydrate slurry exhibited viscoelastic fluid properties. The existence of hydrate substantially increased the apparent viscosity of the mudflow, and when the hydrate formed at a rapid rate, the apparent viscosity rose rapidly. With different initial pressures, the amount of hydrate formed in mudflow was different. A larger water conversion rate would increase the viscosity of the hydrate slurry significantly. Meanwhile, a yield stress measurement was conducted by stress sweep after hydrate formation. When the water conversion fractions were 17.8%, 20.3%, and 21.2%, the yield stresses of the hydrate slurry were 57.8, 465.2, and over 10,000 Pa, respectively. In addition, a frequency test sweep was conducted, and the results showed that the existence of hydrate would significantly increase the elasticity of the slurry.

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Section: Results and Discussionmentioning

confidence: 99%

“…It could be noticed that at a shear rate was 13.6 s –1 the viscosity of the slurry slightly increased. This might be due to the fragmentation and recombination of the hydrate particles when the shear rate was high …”

Section: Results and Discussionmentioning

confidence: 99%

Rheological Properties of Hydrate Slurry Formed from Mudflows in South China Sea

Liu

Zhang

et al. 2021

Energy Fuels

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“…The hydrophilic head groups of Span 80 molecules are close to the quasi-liquid layer, while the hydrophobic tail groups point to the crude oil. The concentration of hydrate anti-agglomerants near the interface usually does not exceed 10 wt % of the oil phase component. − Thus, we set the molecular number of Span 80 in proportion. The molecular numbers of Span 80 are 0, 6, and 12.…”

Section: Calculation Model and Methodsmentioning

confidence: 99%

Aggregation Behavior of Asphalt on the Natural Gas Hydrate Surface with Different Surfactant Coverages

Chen

et al. 2021

J. Phys. Chem. C

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The aggregation behaviors of asphalt on the hydrate surface with different surfactant coverages were studied by molecular simulations. The molecular polarity index of asphalt (10.47 kcal/mol) is higher than that of Span 80 (8.19 kcal/mol). Asphalt is easier to occupy the binding sites between Span 80 and hydrate. Asphalt mainly depends on the π–π interaction to form aggregates. The dispersion interaction up to −114.17 kcal/mol is the main factor to maintain the asphalt aggregate stability. With the increase of surfactant coverage, the polar groups of asphalt are easier to associate with each other, promoting the formation of larger asphalt self-aggregates. The self-aggregation increases the complexity of asphalt stacking, and the proportion of edge-to-face stacking types increases from 40 to 60%. When the Span 80 molecule number reaches 12, the diffusion coefficient of asphalt is only (2.31 ± 0.5) × 10–8 cm2/s. Asphalt with low diffusivity can provide new sites for hydrate nucleation. The results are helpful to understand the aggregation mechanism of asphalt on the hydrate surface. Increasing the concentration of surfactant only is not a good solution to solve blocking-pipeline problems. We need to use surfactant reasonably and give full play to the anti-agglomerant effect of asphalt itself.

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“…Gas hydrate, a type of cage-like crystal structure constructed by water and gas molecules, is generally formed in a low-temperature and high-pressure environment. − The gas molecules, such as methane, ethane, carbon dioxide, and so forth, − are able to be enveloped by the cages of water molecules, forming structure I, II, and H hydrate. − The formation of hydrate becomes a challenge in the development of deep-water fields, where the oil or gas is exposed to the environment of high pressure, low temperature, and water cuts. , Therefore, hydrate forms more easily in the deep water environment and increases the risk of plugging pipelines. − Webb et al studied the effect of water fraction in a water-in-dodecane emulsion on the rheological behavior of a hydrate slurry via a high-pressure rheology apparatus. The results show that the viscosity of the hydrate slurry increases apparently with the increase of water fraction from 5 to 30%.…”

Section: Introductionmentioning

confidence: 99%

Effect of the Ethylene Vinyl Acetate Copolymer on the Induction of Cyclopentane Hydrate in a Water-in-Waxy Oil Emulsion System

Peng¹,

Wang²,

Cheng³

et al. 2021

Langmuir

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In this paper, the effect of the ethylene vinyl acetate (EVA) copolymer, commonly used in improving rheological behavior of waxy oil, is introduced to investigate its effect on the formation of cyclopentane hydrate in a water-in-waxy oil emulsion system. The wax content studied shows a negative effect on the formation of hydrate by elongating its induction time. Besides, the EVA copolymer is found to elongate the induction time of cyclopentane hydrate through the cocrystallization effect with wax molecules adjacent to the oil–water interface.

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Rheology of methane hydrate slurries formed from water-in-oil emulsion with different surfactants concentrations

Cited by 47 publications

References 48 publications

Rheological Properties of Hydrate Slurry Formed from Mudflows in South China Sea

Rheological Properties of Hydrate Slurry Formed from Mudflows in South China Sea

Aggregation Behavior of Asphalt on the Natural Gas Hydrate Surface with Different Surfactant Coverages

Effect of the Ethylene Vinyl Acetate Copolymer on the Induction of Cyclopentane Hydrate in a Water-in-Waxy Oil Emulsion System

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