{"title":"Effect of liquid CO2 phase change on pores and fractures in coal: An experimental study","authors":"Zebiao Jiang, Shikang Gao, Hao Liu, Siliang Chen, Qiaoshun Mo, Feng He","doi":"10.1002/ese3.1845","DOIUrl":null,"url":null,"abstract":"<p>The evolution characteristics of pores and fractures in coal after liquid carbon dioxide (CO<sub>2</sub>) phase change are important factors that determine the permeability increase effect. Therefore, it is critical to correctly understand the influences of liquid CO<sub>2</sub> phase change on pores and fractures in coal. The changes of adsorption and desorption isotherm, pore size, pore volume, and specific surface area of fractured coal and fractured coal were compared by low temperature liquid nitrogen adsorption experiment. In addition, a scanning electron microscope was adopted to observe fracture characteristics of fractured and unfractured coal samples and analyze changes in the connectivity and fracture development. Experimental results show that the fractured coal samples exhibit better hysteresis loops and a larger proportion of gas desorption than the unfractured ones. Fractured coal samples contain more developed pores and fractures compared with unfractured ones, and their fragmentation degree, pore diameter, fracture width, and connectivity of pores and fractures are also better. Besides, the closer the samples from the fracturing boreholes are, the better the fracturing effect. This indicates that liquid CO<sub>2</sub> phase change can effectively enhance the gas transport capacity in pores and fractures in coal. The research results provide a solid basis for the better application of liquid CO<sub>2</sub> phase-change fracturing to the prevention of coal and gas outburst disasters and the realization of efficient gas extraction in deep coal seams.</p>","PeriodicalId":11673,"journal":{"name":"Energy Science & Engineering","volume":"12 9","pages":"3764-3778"},"PeriodicalIF":3.5000,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ese3.1845","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Energy Science & Engineering","FirstCategoryId":"5","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1002/ese3.1845","RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"ENERGY & FUELS","Score":null,"Total":0}
引用次数: 0
Abstract
The evolution characteristics of pores and fractures in coal after liquid carbon dioxide (CO2) phase change are important factors that determine the permeability increase effect. Therefore, it is critical to correctly understand the influences of liquid CO2 phase change on pores and fractures in coal. The changes of adsorption and desorption isotherm, pore size, pore volume, and specific surface area of fractured coal and fractured coal were compared by low temperature liquid nitrogen adsorption experiment. In addition, a scanning electron microscope was adopted to observe fracture characteristics of fractured and unfractured coal samples and analyze changes in the connectivity and fracture development. Experimental results show that the fractured coal samples exhibit better hysteresis loops and a larger proportion of gas desorption than the unfractured ones. Fractured coal samples contain more developed pores and fractures compared with unfractured ones, and their fragmentation degree, pore diameter, fracture width, and connectivity of pores and fractures are also better. Besides, the closer the samples from the fracturing boreholes are, the better the fracturing effect. This indicates that liquid CO2 phase change can effectively enhance the gas transport capacity in pores and fractures in coal. The research results provide a solid basis for the better application of liquid CO2 phase-change fracturing to the prevention of coal and gas outburst disasters and the realization of efficient gas extraction in deep coal seams.
期刊介绍：
Energy Science & Engineering is a peer reviewed, open access journal dedicated to fundamental and applied research on energy and supply and use. Published as a co-operative venture of Wiley and SCI (Society of Chemical Industry), the journal offers authors a fast route to publication and the ability to share their research with the widest possible audience of scientists, professionals and other interested people across the globe. Securing an affordable and low carbon energy supply is a critical challenge of the 21st century and the solutions will require collaboration between scientists and engineers worldwide. This new journal aims to facilitate collaboration and spark innovation in energy research and development. Due to the importance of this topic to society and economic development the journal will give priority to quality research papers that are accessible to a broad readership and discuss sustainable, state-of-the art approaches to shaping the future of energy. This multidisciplinary journal will appeal to all researchers and professionals working in any area of energy in academia, industry or government, including scientists, engineers, consultants, policy-makers, government officials, economists and corporate organisations.
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