SCI和EI收录∣中国化工学会会刊

Chinese Journal of Chemical Engineering ›› 2022, Vol. 43 ›› Issue (3): 50-61.DOI: 10.1016/j.cjche.2021.12.025

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Methane hydrate crystal growth on shell substrate

Xin Jiang1, Baojiang Sun1,2, Zhiyuan Wang1,2, Wantian Zhou1, Jiakai Ji1, Litao Chen1,2   

  1. 1. School of Petroleum Engineering, China University of Petroleum (East China), Qingdao 266580, China;
    2. Key Laboratory of Unconventional Oil and Gas Development, China University of Petroleum (East China), Qingdao 266580, China
  • Received:2021-07-23 Revised:2021-11-15 Online:2022-04-28 Published:2022-03-28
  • Contact: Litao Chen,E-mail:chenlt@upc.edu.cn
  • Supported by:
    Financially supported by the National Natural Science Foundation of China (Nos. 51991365 and 51876222) and China National Petroleum Corporation (CNPC) Major Science and Technology Project (No. ZD2019-184-002) are greatly acknowledged.

Methane hydrate crystal growth on shell substrate

Xin Jiang1, Baojiang Sun1,2, Zhiyuan Wang1,2, Wantian Zhou1, Jiakai Ji1, Litao Chen1,2   

  1. 1. School of Petroleum Engineering, China University of Petroleum (East China), Qingdao 266580, China;
    2. Key Laboratory of Unconventional Oil and Gas Development, China University of Petroleum (East China), Qingdao 266580, China
  • 通讯作者: Litao Chen,E-mail:chenlt@upc.edu.cn
  • 基金资助:
    Financially supported by the National Natural Science Foundation of China (Nos. 51991365 and 51876222) and China National Petroleum Corporation (CNPC) Major Science and Technology Project (No. ZD2019-184-002) are greatly acknowledged.

Abstract: Hydrate crystals growth on the surface of methane bubble (hydrate film) in pure water was studied by using a high-pressure visible microscope under the conditions of subcooling ΔT = 5.44–13.72 K and methane concentration difference ΔC = 2.92–8.19 mol·L-1. It was found the hydrate film is porous and the hydrate crystals grow towards the liquid phase on the film substrate. The crystal morphology and growth rate are affected by ΔT and ΔC. When ΔT < 8.82 K and ΔC < 4.12 mol·L-1, the hydrate grows into scattered columnar crystals, and the axial growth rate of the crystal gradually decreases. When ΔT > 8.82 K or ΔC > 4.12 mol·L-1, the hydrate crystals grow in dendritic shape, and the axial growth rate increases first and then decreases. The perimeter and area of the growing hydrate crystals were measured, and the fractal dimension of hydrate crystal under different ΔC and ΔT was calculated. The results show that the fractal dimension of columnar hydrate crystal is greater than 3. When 3.87 mol·L-1 < ΔC < 4.20 mol·L-1 and 7.4 K < ΔT < 8.8 K, the fractal dimension of columnar hydrate crystal is greater than 4; The fractal dimension of dendritic hydrate crystal is less than 3. When ΔC > 4.77 mol·L-1, ΔT < 8.52 K, the fractal dimension of dendritic hydrate crystal is less than 2.

Key words: Methane, Hydrate, Crystal growth, Morphology, Fractal dimension

摘要: Hydrate crystals growth on the surface of methane bubble (hydrate film) in pure water was studied by using a high-pressure visible microscope under the conditions of subcooling ΔT = 5.44–13.72 K and methane concentration difference ΔC = 2.92–8.19 mol·L-1. It was found the hydrate film is porous and the hydrate crystals grow towards the liquid phase on the film substrate. The crystal morphology and growth rate are affected by ΔT and ΔC. When ΔT < 8.82 K and ΔC < 4.12 mol·L-1, the hydrate grows into scattered columnar crystals, and the axial growth rate of the crystal gradually decreases. When ΔT > 8.82 K or ΔC > 4.12 mol·L-1, the hydrate crystals grow in dendritic shape, and the axial growth rate increases first and then decreases. The perimeter and area of the growing hydrate crystals were measured, and the fractal dimension of hydrate crystal under different ΔC and ΔT was calculated. The results show that the fractal dimension of columnar hydrate crystal is greater than 3. When 3.87 mol·L-1 < ΔC < 4.20 mol·L-1 and 7.4 K < ΔT < 8.8 K, the fractal dimension of columnar hydrate crystal is greater than 4; The fractal dimension of dendritic hydrate crystal is less than 3. When ΔC > 4.77 mol·L-1, ΔT < 8.52 K, the fractal dimension of dendritic hydrate crystal is less than 2.

关键词: Methane, Hydrate, Crystal growth, Morphology, Fractal dimension