学术报告
题 目： Cryogenic Treatment of Coal and Its Application in CBM and Coal Mine Gas Control
煤的深冷处理及其在煤层气和煤矿瓦斯治理中的应用
主 讲 人：Dr. Shimin Liu
刘世民 博士
工作单位：Department of Energy and Mineral Engineering, the Pennsylvania State University, USA
美国宾夕法尼亚州立大学能源与矿业工程系
时 间：At 3:00-4:30 p.m., June 3, 2019
2019年6月3日 下午15:00-16:30
地 点：School of Resource & Environment and Safety Engineering Academic Report Hall (the first floor of Fourth Building)
资源环境与安全工程学院学术报告厅（四教一楼）
刘世民：宾西法尼亚州立大学能源与矿业工程学院副教授、博士生导师。煤炭学报英文版主编。主要从事煤层气、页岩气等领域的科研教学工作。
Bio：
Shimin Liu is an Associate Professor of Energy and Mineral Engineering at Penn State University and he holds Ph.D. degree in Engineering Sciences from Southern Illinois University. His research interests include flow of fluids in porous media (with application to gas flow in coal/shale, coalbed methane reservoir engineering, gas shale reservoir engineering, carbon sequestration in geologic media and abandoned coal mines); imaging (micro-X-ray computed tomography, synchrotron X-ray scattering, neutron scattering/diffracting, scanning/transmission electron microcopy) and analysis to study physical structure of rocks; flow-induced micro-structuring of rocks; geomechanical responses of unconventional reservoirs with depletion. As PI, he has successfully secured funding from various US federal agencies, including US Department of Energy, US National Science Foundation, CDC-NIOSH, Alpha Foundation, SME Foundation and industrial partners with total of external grant with over 3 million US Dollars. Out of his research, he has published more than 90 peer-reviewed journal publications and with ~1500 citations. Right now, he is editor-in-chief for International Journal of Coal Science and Technology. For more details, please refer to his personal web at Penn State at https://www.eme.psu.edu/directory/shimin-liu。
Abstract：
Fracturing using liquid nitrogen (LN2) has been successfully applied in coalbed methane reservoirs stimulation in field since the 1990s. However, the mechanism of LN2 acting on the alteration of pore structure is still obscure. For moisture coal, the cryogenic treatment can provide both frost-heaving force and the expansion force to increase the pore volume and fracture aperture and density. Investigation on the evolution of pore structure predominately provides deep understanding of the CBM performance after cryogenic stimulation and potentially optimizes the fracturing plan in field. This study used the particle method to examine the change in pore structure due to LN2. The particle method eliminates the pre-existing fracturing network and ensures the transport of gas is purely driven by diffusion. In this study, we focus on the micro-pore modification by LN2 treatments. The coal particles were treated by LN2 immersion. The adsorption experiment was conducted to measure the sorption and diffusion behavior of coal. The results indicated that the micropore volume increased by LN2 treatments and thus sorption capacity and diffusion coefficient of coal were improved. This study provides a scientific justification for diffusion improvement and gas production enhancement for high “sorption time” CBM reservoirs.
