Methane hydrates: A future clean energy resource

Yin, Zhenyuan; Linga, Praveen

doi:10.1016/j.cjche.2019.01.005

Cited by 228 publications

(97 citation statements)

References 113 publications

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“…For example, there are significant methane reserves stored in the form of methane clathrates in sediment in the ocean's continental shelves and in permafrost. Permafrost stores of hydrate are particularly vulnerable to warming trends, and significant methane releases from these regions have been noted in the past [2,3]. The potential combustion-related technological issues include safety during gas storage, using hydrates as in situ thermal sources for additional hydrate dissolution, and clean power because hydrates represent a unique fuel that is remarkably diluted (considering the water content) but still flammable.…”

Section: Introductionmentioning

confidence: 99%

Combustion Characteristics of Methane Hydrate Flames

Chien

Dunn‐Rankin

2019

Energies

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This research studies the structure of flames that use laboratory-produced methane hydrates as fuel, specifically for the purpose of identifying their key combustion characteristics. Combustion of a methane hydrate involves multiple phase changes, as large quantities of solid clathrate transform into fuel gas, water vapor, and liquid water during burning. With its unique and stable fuel energy storage capability, studies in combustion are focused on the potential usage of hydrates as an alternative fuel source or on their fire safety. Considering methane hydrate as a conventional combustion energy resource and studying hydrate combustion using canonical experimental configurations or methodology are challenges. This paper presents methane hydrate flame geometries from the time they can be ignited through their extinguishment. Ignition and burning behavior depend on the hydrate initial temperature and whether the clathrates are chunks or monolithic shapes. These behaviors are the subject of this research. Physical properties that affect methane hydrate in burning can include packing density, clathrate fraction, and surface area. Each of these modifies the time or the temperature needed to ignite the hydrate flames as well as their subsequent burning rate, thus every effort is made to keep consistent samples. Visualization methods used in combustion help identify flame characteristics, including pure flame images that give reaction zone size and shape and hydrate flame spectra to identify important species. The results help describe links between hydrate fuel characteristics and their resulting flames.

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Section: Introductionmentioning

confidence: 99%

Combustion Characteristics of Methane Hydrate Flames

Chien

Dunn‐Rankin

2019

Energies

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“…However, realizing long-term commercial gas production from natural-gas hydrate reservoirs still comes with many challenges. Further works should be carried out to narrow knowledge gaps between laboratory-scale studies and reservoir-scale tests [6].…”

Section: Introductionmentioning

confidence: 99%

One-Dimensional Study on Hydrate Formation from Migrating Dissolved Gas in Sandy Sediments

Rehemituli

Zhang

et al. 2020

Energies

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Upward migration of gas-dissolved pore fluid is an important mechanism for many naturally occurring hydrate reservoirs. However, there is limited understanding in this scenario of hydrate formation in sediments. In this preliminary work, hydrate formation and accumulation from dissolved gas in sandy sediments along the migration direction of brine was investigated using a visual hydrate simulator. Visual observation was employed to capture the morphology of hydrates in pores through three sapphire tubes. Meanwhile, the resistivity evolution of sediments was detected to characterize hydrate distribution in sediments. It was observed that hydrates initially formed as a thin film or dispersed crystals and then became a turbid colloidal solution. With hydrate growth, the colloidal solution converted to massive solid hydrates. Electrical resistivity experienced a three-stage evolution process corresponding to the three observed hydrate morphologies. The results of resistivity analysis also indicated that the bottom–up direction of hydrate growth was consistent with the flow direction of brine, and two hydrate accumulation centers successively appeared in the sediments. Hydrates preferentially formed and accumulated in certain depths of the sediments, resulting in heterogeneous hydrate distribution. Even under low saturation, the occurrence of heterogeneous hydrates led to the sharp reduction of sediment permeability.

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“…The vast resource volume of CH4 (~3,000 TCM) in naturally-occurring MH-bearing sediments [5] and their high energy storage capacity (170 vCH4/vH2O) make MHs a promising future energy resource [6]. This realization has led to an explosive and intensifying research interest and activities by both the academic and the industry communities over the past two decades [7].…”

Section: Introductionmentioning

confidence: 99%

On the importance of phase saturation heterogeneity in the analysis of laboratory studies of hydrate dissociation

2019

Self Cite

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Methane hydrates (MHs) have been considered as the future source of energy because of its vast resource volume and high energy density. Energy recovery from MH-bearing sediments has attracted intensifying research activities. Fundamentally, heat transfer, fluid flow through porous media, and the kinetics of hydrate reaction are the three key processes controlling the behavior of MH dissociation and the associated fluid production. Earlier studies have suggested that heterogeneous spatial distribution of SH is inevitable in MHbearing samples synthesized in laboratory. In this paper, we extend our study to analyze numerically the simulation results from the two realizations of the samples (homogeneous and heterogeneous) to identify differences in the fluid production and to determine if they are sufficiently different. Additionally, we conduct a sensitivity analysis and a statistical analysis on the key transport and kinetic rate parameters that could affect hydrate dissociation and fluid production in the context of a heterogeneous hydrate-bearing sample, in an effort to provide insights that could lead to improved designs for laboratory experiments and (possibly) field applications. Our results suggest that the approximation of an artificial hydrate-bearing core with heterogeneous phase saturations by an assumption of uniform phase saturation distributions results in practically similar fluid production profile except for the very early stage with maximum 20.0% deviation in the water production. From the sensitivity and statistical analysis, we determine that gas production depends strongly on the kinetic rate constant, Kd 0 and the composite thermal conductivity of the hydrate-bearing sediments, λθ; while, water production is very sensitive to Kd 0 and the absolute permeability of the sandy medium, k. Understanding the effect of phase 2 heterogeneity and the relative importance of key parameters on the production behavior of hydrate-bearing sediments could provide basis for novel production technologies that lead to enhanced gas production and energy efficiency in the energy recovery process.

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Methane hydrates: A future clean energy resource

Cited by 228 publications

References 113 publications

Combustion Characteristics of Methane Hydrate Flames

Combustion Characteristics of Methane Hydrate Flames

One-Dimensional Study on Hydrate Formation from Migrating Dissolved Gas in Sandy Sediments

On the importance of phase saturation heterogeneity in the analysis of laboratory studies of hydrate dissociation

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