SCI和EI收录∣中国化工学会会刊

Chinese Journal of Chemical Engineering ›› 2019, Vol. 27 ›› Issue (9): 2081-2088.DOI: 10.1016/j.cjche.2019.02.007

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Evidence for pore-filling gas hydrates in the sediments through morphology observation

Wenxiang Zhang, Shuanshi Fan, Yanhong Wang, Xuemei Lang, Kai Guo, Jianbiao Chen   

  1. Key Lab of Enhanced Heat Transfer and Energy Conservation Ministry of Education, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640, China
  • Received:2018-11-12 Revised:2019-01-08 Online:2019-12-04 Published:2019-09-28
  • Contact: Wenxiang Zhang, Yanhong Wang
  • Supported by:
    Supported by the National Key Research and Development Program (2016YFC0304006, 2017YFC0307302, 2017YFC0307303), the National Natural Science Foundation of China (51576069, 51876069), the China Postdoctoral Science Foundation (2018M633052), and the Fundamental Research Funds for the Central Universities (D2182630).

Evidence for pore-filling gas hydrates in the sediments through morphology observation

Wenxiang Zhang, Shuanshi Fan, Yanhong Wang, Xuemei Lang, Kai Guo, Jianbiao Chen   

  1. Key Lab of Enhanced Heat Transfer and Energy Conservation Ministry of Education, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640, China
  • 通讯作者: Wenxiang Zhang, Yanhong Wang
  • 基金资助:
    Supported by the National Key Research and Development Program (2016YFC0304006, 2017YFC0307302, 2017YFC0307303), the National Natural Science Foundation of China (51576069, 51876069), the China Postdoctoral Science Foundation (2018M633052), and the Fundamental Research Funds for the Central Universities (D2182630).

Abstract: To provide an evidence of natural gas hydrate occurrence state, a series of experiments on multiple growth and dissociation of 90.0% methane/10.0% propane hydrates at 1.3 MPa and 270.15 K were carried out in two sediments for morphology observation via a visible jacketed-reactor. The gas hydrate crystals were observed to form and grow on the surface of sediments at the initial growth. During the thermal decomposition, gas and liquid products had an unceasingly impact on the sediments, then gas/liquid-solid migration occurred, and a large number of cavitation appeared. In the later growth and dissociation experiments, the gas hydrate particles were in suspension or supporting states in the interstitial pore space between the sediment particles, indicating that the gas hydrate displayed a pore-filling characteristics. Through analyzing the distribution of gas hydrates and bubbles, it was found that the amount of gas hydrates distributed in the sediments was improved with multiple growth-dissociation cycle proceedings. Gas migration enhanced the sediment movement, which led to the appearance of the increasing quantity of gas bubbles in the sediments during cycles. Salts affected the growth of the gas hydrates and the migration of sediment grains, which also restricted the accumulation of gas bubbles in the sediments. According to the Raman analysis, the results showed that sII hydrates were formed for CH4 and C3H8 gas mixtures in different sediments and solutions with hydration number of 5.84-6.53. The Salt restricted the access of gas into the hydrate cages.

Key words: Gas hydrate, Sediments, Growth, Dissociation, Pore-filling

摘要: To provide an evidence of natural gas hydrate occurrence state, a series of experiments on multiple growth and dissociation of 90.0% methane/10.0% propane hydrates at 1.3 MPa and 270.15 K were carried out in two sediments for morphology observation via a visible jacketed-reactor. The gas hydrate crystals were observed to form and grow on the surface of sediments at the initial growth. During the thermal decomposition, gas and liquid products had an unceasingly impact on the sediments, then gas/liquid-solid migration occurred, and a large number of cavitation appeared. In the later growth and dissociation experiments, the gas hydrate particles were in suspension or supporting states in the interstitial pore space between the sediment particles, indicating that the gas hydrate displayed a pore-filling characteristics. Through analyzing the distribution of gas hydrates and bubbles, it was found that the amount of gas hydrates distributed in the sediments was improved with multiple growth-dissociation cycle proceedings. Gas migration enhanced the sediment movement, which led to the appearance of the increasing quantity of gas bubbles in the sediments during cycles. Salts affected the growth of the gas hydrates and the migration of sediment grains, which also restricted the accumulation of gas bubbles in the sediments. According to the Raman analysis, the results showed that sII hydrates were formed for CH4 and C3H8 gas mixtures in different sediments and solutions with hydration number of 5.84-6.53. The Salt restricted the access of gas into the hydrate cages.

关键词: Gas hydrate, Sediments, Growth, Dissociation, Pore-filling