Xenon Hydrate as an Analog of Methane Hydrate in Geologic Systems Out of Thermodynamic Equilibrium
Methane hydrate occurs naturally under pressure and temperature conditions that are not straightforward to replicate experimentally. Xenon has emerged as an attractive laboratory alternative to methane for studying hydrate formation and dissociation in multiphase systems, given that it forms hydrate...
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| Format: | Article |
| Language: | English |
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American Geophysical Union (AGU)
2020
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| Online Access: | https://hdl.handle.net/1721.1/125592 |
| _version_ | 1811071441460789248 |
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| author | Fu, Xiaojing Waite, William F. Cueto-Felgueroso Landeira, Luis Juanes, Ruben |
| author2 | Massachusetts Institute of Technology. Department of Civil and Environmental Engineering |
| author_facet | Massachusetts Institute of Technology. Department of Civil and Environmental Engineering Fu, Xiaojing Waite, William F. Cueto-Felgueroso Landeira, Luis Juanes, Ruben |
| author_sort | Fu, Xiaojing |
| collection | MIT |
| description | Methane hydrate occurs naturally under pressure and temperature conditions that are not straightforward to replicate experimentally. Xenon has emerged as an attractive laboratory alternative to methane for studying hydrate formation and dissociation in multiphase systems, given that it forms hydrates under milder conditions. However, building reliable analogies between the two hydrates requires systematic comparisons, which are currently lacking. We address this gap by developing a theoretical and computational model of gas hydrates under equilibrium and nonequilibrium conditions. We first compare equilibrium phase behaviors of the Xe·H2O and CH4·H2O systems by calculating their isobaric phase diagram, and then study the nonequilibrium kinetics of interfacial hydrate growth using a phase field model. Our results show that Xe·H2O is a good experimental analog to CH4·H2O, but there are key differences to consider. In particular, the aqueous solubility of xenon is altered by the presence of hydrate, similar to what is observed for methane; but xenon is consistently less soluble than methane. Xenon hydrate has a wider nonstoichiometry region, which could lead to a thicker hydrate layer at the gas-liquid interface when grown under similar kinetic forcing conditions. For both systems, our numerical calculations reveal that hydrate nonstoichiometry coupled with hydrate formation dynamics leads to a compositional gradient across the hydrate layer, where the stoichiometric ratio increases from the gas-facing side to the liquid-facing side. Our analysis suggests that accurate composition measurements could be used to infer the kinetic history of hydrate formation in natural settings where gas is abundant. ©2019. American Geophysical Union. All Rights Reserved. |
| first_indexed | 2024-09-23T08:51:00Z |
| format | Article |
| id | mit-1721.1/125592 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T08:51:00Z |
| publishDate | 2020 |
| publisher | American Geophysical Union (AGU) |
| record_format | dspace |
| spelling | mit-1721.1/1255922022-09-30T11:42:50Z Xenon Hydrate as an Analog of Methane Hydrate in Geologic Systems Out of Thermodynamic Equilibrium Fu, Xiaojing Waite, William F. Cueto-Felgueroso Landeira, Luis Juanes, Ruben Massachusetts Institute of Technology. Department of Civil and Environmental Engineering Methane hydrate occurs naturally under pressure and temperature conditions that are not straightforward to replicate experimentally. Xenon has emerged as an attractive laboratory alternative to methane for studying hydrate formation and dissociation in multiphase systems, given that it forms hydrates under milder conditions. However, building reliable analogies between the two hydrates requires systematic comparisons, which are currently lacking. We address this gap by developing a theoretical and computational model of gas hydrates under equilibrium and nonequilibrium conditions. We first compare equilibrium phase behaviors of the Xe·H2O and CH4·H2O systems by calculating their isobaric phase diagram, and then study the nonequilibrium kinetics of interfacial hydrate growth using a phase field model. Our results show that Xe·H2O is a good experimental analog to CH4·H2O, but there are key differences to consider. In particular, the aqueous solubility of xenon is altered by the presence of hydrate, similar to what is observed for methane; but xenon is consistently less soluble than methane. Xenon hydrate has a wider nonstoichiometry region, which could lead to a thicker hydrate layer at the gas-liquid interface when grown under similar kinetic forcing conditions. For both systems, our numerical calculations reveal that hydrate nonstoichiometry coupled with hydrate formation dynamics leads to a compositional gradient across the hydrate layer, where the stoichiometric ratio increases from the gas-facing side to the liquid-facing side. Our analysis suggests that accurate composition measurements could be used to infer the kinetic history of hydrate formation in natural settings where gas is abundant. ©2019. American Geophysical Union. All Rights Reserved. DOE (award no. DE-FE0013999) DOE (award no.DE-SC0018357) DOE Interagency Agreement (DE-FE0023495) Miller Research Fellowship UC Berkeley U.S.Geological Survey's Gas Hydrate Project U.S.Geological Survey Coastal,Marine Hazards and Resources Program Spanish Ministry of Economy and Competitiveness(grant no. RYC-2012-11704) Spanish Ministry of Economy and Competitiveness (grant no. CTM2014-54312-P) MIT International Science and Technology Initiatives (Seed Fund grant) 2020-05-29T21:47:40Z 2020-05-29T21:47:40Z 2019-05 2019-01 2020-05-27T19:54:34Z Article http://purl.org/eprint/type/JournalArticle 1525-2027 https://hdl.handle.net/1721.1/125592 Fu, Xiaojing et al., "Xenon Hydrate as an Analog of Methane Hydrate in Geologic Systems Out of Thermodynamic Equilibrium." Geochemistry, Geophysics, Geosystems 20, 5 (May 2019): 2462-72 doi. 10.1029/2019GC008250 ©2019 Authors en https://dx.doi.org/10.1029/2019GC008250 Geochemistry, Geophysics, Geosystems Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf American Geophysical Union (AGU) Other repository |
| spellingShingle | Fu, Xiaojing Waite, William F. Cueto-Felgueroso Landeira, Luis Juanes, Ruben Xenon Hydrate as an Analog of Methane Hydrate in Geologic Systems Out of Thermodynamic Equilibrium |
| title | Xenon Hydrate as an Analog of Methane Hydrate in Geologic Systems Out of Thermodynamic Equilibrium |
| title_full | Xenon Hydrate as an Analog of Methane Hydrate in Geologic Systems Out of Thermodynamic Equilibrium |
| title_fullStr | Xenon Hydrate as an Analog of Methane Hydrate in Geologic Systems Out of Thermodynamic Equilibrium |
| title_full_unstemmed | Xenon Hydrate as an Analog of Methane Hydrate in Geologic Systems Out of Thermodynamic Equilibrium |
| title_short | Xenon Hydrate as an Analog of Methane Hydrate in Geologic Systems Out of Thermodynamic Equilibrium |
| title_sort | xenon hydrate as an analog of methane hydrate in geologic systems out of thermodynamic equilibrium |
| url | https://hdl.handle.net/1721.1/125592 |
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