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Kou X, Zhang H, Li XS, Chen ZY, Wang Y. Interfacial Heat and Mass Transfer Effects on Secondary Hydrate Formation under Different Dissociation Conditions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024. [PMID: 38330279 DOI: 10.1021/acs.langmuir.3c03289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/10/2024]
Abstract
Secondary hydrate formation or hydrate reformation poses a serious threat to the oil and gas transportation safety and natural gas hydrate exploitation efficiency. The hydrate reformation behaviors in porous media have been widely studied in large simulators due to their importance in traditional industries and new energy resources. However, it is difficult to understand the interfacial effects of hydrate reformation on the surface and in micropores of the porous media via a basic experimental apparatus. In this work, in situ X-ray computed tomography (X-CT) technology is used to detect the period, distribution, volume, and morphology characteristics of secondary hydrate formation during hydrate dissociation under depressurization, thermal stimulation, and the combined conditions. It is found that the secondary hydrate formation is inevitable under any conditions of hydrate dissociation. The secondary hydrate morphology varies among porous, grain-enveloping, grain-cementing, granular, and patchy structures, which are closely correlated to the hydrate reformation region and gas/water saturated conditions during hydrate dissociation. Accordingly, we revealed that the interfacial superheating phenomenon before hydrate dissociation could provide a supercooling condition for hydrate reformation. The gas flow along the interface of pores and inside the liquid water, as well as gas accumulation in noninterconnected pores, would exaggerate the hydrate reformation by increasing the local pore pressure. Meanwhile, the hydrate reformation aggravates the nonuniform distribution of gas hydrates in pores. In order to avoid hydrate reformation during dissociation, we further compared hydrate reformation and dissociation behaviors under three hydrate dissociation conditions. It is revealed that the combination of thermal stimulation and depressurization is an effective method for hydrate dissociation by retarding secondary hydrate formation. This study provides visual evidence and an interaction mechanism between interfacial heat and mass transfer, as well as secondary hydrate formation behaviors, which can be favorable for future quantitative research on secondary hydrate formation in different scales under various dissociation conditions.
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Affiliation(s)
- Xuan Kou
- Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, P. R. China
- CAS Key Laboratory of Gas Hydrate, Guangzhou 510640, P. R. China
- Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development, Guangzhou 510640, P. R. China
- Guangzhou Center for Gas Hydrate Research, Chinese Academy of Sciences, Guangzhou 510640, P. R. China
| | - Heng Zhang
- Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, P. R. China
- CAS Key Laboratory of Gas Hydrate, Guangzhou 510640, P. R. China
- Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development, Guangzhou 510640, P. R. China
- Guangzhou Center for Gas Hydrate Research, Chinese Academy of Sciences, Guangzhou 510640, P. R. China
| | - Xiao-Sen Li
- Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, P. R. China
- CAS Key Laboratory of Gas Hydrate, Guangzhou 510640, P. R. China
- Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development, Guangzhou 510640, P. R. China
- Guangzhou Center for Gas Hydrate Research, Chinese Academy of Sciences, Guangzhou 510640, P. R. China
| | - Zhao-Yang Chen
- Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, P. R. China
- CAS Key Laboratory of Gas Hydrate, Guangzhou 510640, P. R. China
- Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development, Guangzhou 510640, P. R. China
- Guangzhou Center for Gas Hydrate Research, Chinese Academy of Sciences, Guangzhou 510640, P. R. China
| | - Yi Wang
- Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, P. R. China
- CAS Key Laboratory of Gas Hydrate, Guangzhou 510640, P. R. China
- Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development, Guangzhou 510640, P. R. China
- Guangzhou Center for Gas Hydrate Research, Chinese Academy of Sciences, Guangzhou 510640, P. R. China
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