Promoting Effect of Ultra-Fine Bubbles on CO<sub>2</sub> Hydrate Formation
When gas hydrates dissociate into gas and liquid water, many gas bubbles form in the water. The large bubbles disappear after several minutes due to their buoyancy, while a large number of small bubbles (particularly sub-micron-order bubbles known as ultra-fine bubbles (UFBs)) remain in the water fo...
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doaj-96ca88a2df20427bb74a7544315863292021-06-30T23:39:35ZengMDPI AGEnergies1996-10732021-06-01143386338610.3390/en14123386Promoting Effect of Ultra-Fine Bubbles on CO<sub>2</sub> Hydrate FormationTsutomu Uchida0Hiroshi Miyoshi1Kenji Yamazaki2Kazutoshi Gohara3Faculty of Engineering, Hokkaido University, Sapporo 060-8628, JapanGraduate School of Engineering, Hokkaido University, Sapporo 060-8628, JapanFaculty of Engineering, Hokkaido University, Sapporo 060-8628, JapanFaculty of Engineering, Hokkaido University, Sapporo 060-8628, JapanWhen gas hydrates dissociate into gas and liquid water, many gas bubbles form in the water. The large bubbles disappear after several minutes due to their buoyancy, while a large number of small bubbles (particularly sub-micron-order bubbles known as ultra-fine bubbles (UFBs)) remain in the water for a long time. In our previous studies, we demonstrated that the existence of UFBs is a major factor promoting gas hydrate formation. We then extended our research on this issue to carbon dioxide (CO<sub>2</sub>) as it forms structure-I hydrates, similar to methane and ethane hydrates explored in previous studies; however, CO<sub>2</sub> saturated solutions present severe conditions for the survival of UFBs. The distribution measurements of CO<sub>2</sub> UFBs revealed that their average size was larger and number density was smaller than those of other hydrocarbon UFBs. Despite these conditions, the CO<sub>2</sub> hydrate formation tests confirmed that CO<sub>2</sub> UFBs played important roles in the expression of the promoting effect. The analysis showed that different UFB preparation processes resulted in different promoting effects. These findings can aid in better understanding the mechanism of the promoting (or memory) effect of gas hydrate formation.https://www.mdpi.com/1996-1073/14/12/3386nanobubblememory effectcarbon dioxideinduction time |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Tsutomu Uchida Hiroshi Miyoshi Kenji Yamazaki Kazutoshi Gohara |
spellingShingle |
Tsutomu Uchida Hiroshi Miyoshi Kenji Yamazaki Kazutoshi Gohara Promoting Effect of Ultra-Fine Bubbles on CO<sub>2</sub> Hydrate Formation Energies nanobubble memory effect carbon dioxide induction time |
author_facet |
Tsutomu Uchida Hiroshi Miyoshi Kenji Yamazaki Kazutoshi Gohara |
author_sort |
Tsutomu Uchida |
title |
Promoting Effect of Ultra-Fine Bubbles on CO<sub>2</sub> Hydrate Formation |
title_short |
Promoting Effect of Ultra-Fine Bubbles on CO<sub>2</sub> Hydrate Formation |
title_full |
Promoting Effect of Ultra-Fine Bubbles on CO<sub>2</sub> Hydrate Formation |
title_fullStr |
Promoting Effect of Ultra-Fine Bubbles on CO<sub>2</sub> Hydrate Formation |
title_full_unstemmed |
Promoting Effect of Ultra-Fine Bubbles on CO<sub>2</sub> Hydrate Formation |
title_sort |
promoting effect of ultra-fine bubbles on co<sub>2</sub> hydrate formation |
publisher |
MDPI AG |
series |
Energies |
issn |
1996-1073 |
publishDate |
2021-06-01 |
description |
When gas hydrates dissociate into gas and liquid water, many gas bubbles form in the water. The large bubbles disappear after several minutes due to their buoyancy, while a large number of small bubbles (particularly sub-micron-order bubbles known as ultra-fine bubbles (UFBs)) remain in the water for a long time. In our previous studies, we demonstrated that the existence of UFBs is a major factor promoting gas hydrate formation. We then extended our research on this issue to carbon dioxide (CO<sub>2</sub>) as it forms structure-I hydrates, similar to methane and ethane hydrates explored in previous studies; however, CO<sub>2</sub> saturated solutions present severe conditions for the survival of UFBs. The distribution measurements of CO<sub>2</sub> UFBs revealed that their average size was larger and number density was smaller than those of other hydrocarbon UFBs. Despite these conditions, the CO<sub>2</sub> hydrate formation tests confirmed that CO<sub>2</sub> UFBs played important roles in the expression of the promoting effect. The analysis showed that different UFB preparation processes resulted in different promoting effects. These findings can aid in better understanding the mechanism of the promoting (or memory) effect of gas hydrate formation. |
topic |
nanobubble memory effect carbon dioxide induction time |
url |
https://www.mdpi.com/1996-1073/14/12/3386 |
work_keys_str_mv |
AT tsutomuuchida promotingeffectofultrafinebubblesoncosub2subhydrateformation AT hiroshimiyoshi promotingeffectofultrafinebubblesoncosub2subhydrateformation AT kenjiyamazaki promotingeffectofultrafinebubblesoncosub2subhydrateformation AT kazutoshigohara promotingeffectofultrafinebubblesoncosub2subhydrateformation |
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1721350801448763392 |