•  
  •  
 

Coal Geology & Exploration

Abstract

Objective Coal briquettes used for physical simulations of gas disasters in coal mines generally exhibit low strength and high permeability. To address this challenge, this study developed a new hot pressing process and a temperature control method to optimize the mechanical and seepage performance of coal briquettes. Methods First, an optimal mixing ratio scheme was determined based on the Horsfield close-packing theory, and coal briquettes were prepared at different temperatures using an independently developed hot pressing system. Subsequently, the microstructure evolution patterns of the hot-pressed coal briquettes were characterized using an X-ray diffractometer (XRD), an X-ray photoelectron spectrometer (XPS), a scanning electron microscope (SEM), and a nuclear magnetic resonance (NMR) core analyzer. Last, using a similarity measurement method based on the Mahalanobis distance, a similarity matrix for the mechanical strength, permeability, and density of the coal briquettes and raw coal was constructed. Accordingly, the optimum temperature for coal briquette preparation was determined using the golden section method. Results and Conclusions The results indicate that as the temperature increased from 250 ℃ to 350 ℃, the content of aromatic hydrocarbons or aliphatic carbon (C−C/C−H) in the molecular structure of the coal briquettes increased initially and then decreased. In contrast, the interlayer spacing (d002) of aromatic fringes gradually decreased and then remained constant after the temperature reached 302.8 ℃, while both the microcrystalline height (Lc) and diameter (Lₐ) increased gradually. Concurrently, the cumulative porosity decreased initially and then increased, with the hot-pressed coal briquettes maintaining smooth surfaces and tightly bound coal particles within the temperature range of >288.2 ℃–326.4 ℃. After five optimizations using the golden section method, the hot-pressed coal briquettes exhibited the highest C−C/C−H content and the lowest cumulative porosity at 311.8 ℃. These characteristics were most comparable to those of the raw coal. At this temperature, the hot-pressed coal briquettes showed a uniaxial compressive strength, permeability, and density of 8.42 MPa, 1.59×10–3 μm2, and 1.116 g/cm3, respectively, representing an increase of 7.8 MPa, a decrease of 0.27×10–3 μm2, and an increase of 0.056 g/cm3 compared to hot-pressed coal briquettes. The results of this study provide valuable guidance for enhancing the similarity between coal briquettes and raw coal and thus improving the realistic level of the physical simulations of gas disasters in coal mines.

Keywords

gas disaster in a coal mine, hot-pressed coal briquette, microstructure, uniaxial compressive strength (UCS), permeability, temperature control method

DOI

10.12363/issn.1001-1986.26.01.0015

Reference

[1] 胡汉舟. 能源供应保障有力 绿色转型加速推进[N]. 中国信息报，2026-01-21(002).

[2] 国家统计局. 中华人民共和国2025年国民经济和社会发展统计公报[EB/OL]. (2026-02-28) [2026-07-29]. https://www.stats.gov.cn/zwfwck/sjfb/202602/t20260228_1962662.html.

[3] 袁亮. 深部采动响应与灾害防控研究进展[J]. 煤炭学报,2021,46(3):716−725 YUAN Liang. Research progress of mining response and disaster prevention and control in deep coal mines[J]. Journal of China Coal Society,2021,46(3):716−725

[4] ZHANG Meng,LIU Peirong,ZHANG Lei,et al. The size effect of chamber on the dynamic characteristics of coal and gas outburst[J]. Fuel,2025,389:134628.

[5] 袁亮,王恩元,马衍坤,等. 我国煤岩动力灾害研究进展及面临的科技难题[J]. 煤炭学报,2023,48(5):1825−1845 YUAN Liang,WANG Enyuan,MA Yankun,et al. Research progress of coal and rock dynamic disasters and scientific and technological problems in China[J]. Journal of China Coal Society,2023,48(5):1825−1845

[6] 王恩元,张国锐,张超林,等. 我国煤与瓦斯突出防治理论技术研究进展与展望[J]. 煤炭学报,2022,47(1):297−322 WANG Enyuan,ZHANG Guorui,ZHANG Chaolin,et al. Research progress and prospect on theory and technology for coal and gas outburst control and protection in China[J]. Journal of China Coal Society,2022,47(1):297−322

[7] 曹代勇,琚宜文,夏玉成,等. 中国煤田构造研究的史实概览、主要进展与前景展望[J]. 煤田地质与勘探,2025,53(5):1−23 CAO Daiyong,JU Yiwen,XIA Yucheng,et al. Historical overview,advancements,and future prospects of coalfield structure research in China[J]. Coal Geology & Exploration,2025,53(5):1−23

[8] 张超林，李运富，李忠辉，等. 深部开采诱发煤与瓦斯突出的煤体失稳机制[J]. 煤田地质与勘探，2026，54(5)：100−112. Citation：ZHANG Chaolin，LI Yunfu，LI Zhonghui，et al. Mechanisms underlying coal instability during coal and gas outbursts induced by deep mining[J]. Coal Geology & Exploration，2026，54(5)：100−112.

[9] ZHAO Wei,DONG Huzi,YUAN Yuan,et al. Evolution law of coal and gas outburst hole shapes with varying underground stress conditions:Numerical analysis and on–scene evidence[J]. Fuel,2024,360:130531.

[10] ZHAO Yuqiong,ZHANG Yongfa,ZHANG Huirong,et al. Structural characterization of carbonized briquette obtained from anthracite powder[J]. Journal of Analytical and Applied Pyrolysis,2015,112:290−297.

[11] LI Kejiang,KHANNA R,ZHANG Jianliang,et al. Comprehensive investigation of various structural features of bituminous coals using advanced analytical techniques[J]. Energy & Fuels,2015,29(11):7178−7189.

[12] 李树刚,赵鹏翔,林海飞,等. 煤岩瓦斯“固–气”耦合物理模拟相似材料特性实验研究[J]. 煤炭学报,2015,40(1):80−86 LI Shugang,ZHAO Pengxiang,LIN Haifei,et al. Study on character of physical simulation similar material of coal–rock and gas solid–gas coupling[J]. Journal of China Coal Society,2015,40(1):80−86

[13] 刘星光. 含瓦斯煤变形破坏特征及渗透行为研究[D]. 徐州：中国矿业大学，2013. LIU Xingguang. Study on the deformation and failure characteristics and the permeation behavior of gas–saturated coal[D]. Xuzhou：China University of Mining and Technology，2013.

[14] 张庆贺,李术才,王汉鹏,等. 不同强度含瓦斯型煤瞬间揭露致突特征及其影响机制[J]. 采矿与安全工程学报,2017,34(4):817−824 ZHANG Qinghe,LI Shucai,WANG Hanpeng,et al. Influence mechanism and outburst characteristics during revealing different intensity coal containing gas[J]. Journal of Mining & Safety Engineering,2017,34(4):817−824

[15] FRENCH R，REEVES R A. Method of manufacturing coke from low grade coal：US–8673032–B2[P]. 2014-03-18.

[16] MORI A,YUNIATI M D,MURSITO A T,et al. Preparation of coke from Indonesian lignites by a sequence of hydrothermal treatment,hot briquetting,and carbonization[J]. Energy & Fuels,2013,27(11):6607−6616.

[17] 董怡静,韩雨贞,侯泉林,等. 煤变形产气的力化学机理探讨[J]. 煤炭学报,2017,42(4):942−949 DONG Yijing,HAN Yuzhen,HOU Quanlin,et al. Mechanochemistry mechanism of gas generation during coal deformation[J]. Journal of China Coal Society,2017,42(4):942−949

[18] 孟庆春，戎晓霞，包春兵. 优选法与统筹法及其创新性应用[M]. 济南：山东大学出版社，2020.

[19] 张干清,龚宪生,沈杰,等. 基于黄金分割二分法鞍点线抽样的可靠性分析[J]. 湖南大学学报(自然科学版),2012,39(11):52−57 ZHANG Ganqing,GONG Xiansheng,SHEN Jie,et al. Reliability analysis based on saddlepoint approximation–line sampling method of golden section dichotomy[J]. Journal of Hunan University (Natural Sciences),2012,39(11):52−57

[20] 潘贵豪,明世祥,王艳辉,等. 放矿截止品位动态优化方法研究及应用[J]. 矿业研究与开发,2008,28(4):6−8 PAN Guihao,MING Shixiang,WANG Yanhui,et al. Research and application of dynamic optimization method of cut–off grade for ore drawing[J]. Mining Research and Development,2008,28(4):6−8

[21] 汪西莉,焦李成. 一种基于马氏距离的支持向量快速提取算法[J]. 西安电子科技大学学报,2004,31(4):639−643 WANG Xili,JIAO Licheng. A fast algorithm for extracting the support vector on the Mahalanobis distance[J]. Journal of Xidian University,2004,31(4):639−643

[22] 甘青青,许江,蔡果良,等. 升温速率对热压型煤微结构演化规律及力学、渗流特性的影响[J]. 矿业科学学报,2024,9(5):786−796 GAN Qingqing,XU Jiang,CAI Guoliang,et al. Effect of heating rate on microstructure evolution and mechanical–seepage characteristics of hot–pressed briquettes[J]. Journal of Mining Science and Technology,2024,9(5):786−796

[23] ZHANG Xiaopei,ZHANG Cheng,TAN Peng,et al. Effects of hydrothermal upgrading on the physicochemical structure and gasification characteristics of Zhundong coal[J]. Fuel Processing Technology,2018,172:200−208.

[24] 张殿凯,李艳红,常丽萍,等. 弥勒褐煤结构特征及其分子模型构建[J]. 燃料化学学报,2021,49(6):727−734 ZHANG Diankai,LI Yanhong,CHANG Liping,et al. Structural characteristics of Mile lignite and its molecular model construction[J]. Journal of Fuel Chemistry and Technology,2021,49(6):727−734

[25] QI Lingling,WANG Zeqi,FAN Long,et al. Effects of degassing temperature and particle size on pore structure characterization of anthracite coal[J]. Powder Technology,2025,457:120895.

[26] SHI Yu,LIN Baiquan,LIU Ting. Confinement pressure–rising response and its influence on pore–fracture structure evolution of gas–containing coal under thermal stimulation[J]. Measurement,2025,253:117573.

[27] 褚廷湘,杨鑫磊,余明高,等. 煤体破碎粉化微观结构演变及诱导自燃活化机制[J]. 煤炭学报,2026,51(5):3018−3033 CHU Tingxiang,YANG Xinlei,YU Minggao,et al. Microstructure evolution and activation mechanism of inducing coal spontaneous combustion by crushing and pulverization[J]. Journal of China Coal Society,2026,51(5):3018−3033

[28] ZHANG Lanjun,LI Zenghua,YANG Yongliang,et al. Effect of acid treatment on the characteristics and structures of high–sulfur bituminous coal[J]. Fuel,2016,184:418−429.

[29] MA Teng,ZHAI Xiaowei,XIAO Yang,et al. Study on the influence of key active groups on gas products in spontaneous combustion of coal[J]. Fuel,2023,344:128020.

[30] 代世峰,任德贻,宋建芳,等. 应用XPS研究镜煤中有机硫的存在形态[J]. 中国矿业大学学报,2002,31(3):225−228 DAI Shifeng,REN Deyi,SONG Jianfang,et al. Application of XPS in research on occurrence of organic sulfur in vitrain[J]. Journal of China University of Mining & Technology,2002,31(3):225−228

[31] 姚艳斌,刘大锰,蔡益栋,等. 基于NMR和X–CT的煤的孔裂隙精细定量表征[J]. 中国科学:地球科学,2010,40(11):1598−1607 YAO Yanbin,LIU Dameng,CAI Yidong,et al. Advanced characterization of pores and fractures in coals by nuclear magnetic resonance and X–ray computed tomography[J]. Science China:Earth Sciences,2010,40(11):1598−1607

[32] 龚国波,孙伯勤,刘买利,等. 岩心孔隙介质中流体的核磁共振弛豫[J]. 波谱学杂志,2006,23(3):379−395 GONG Guobo,SUN Boqin,LIU Maili,et al. NMR relaxation of the fluid in rock porous media[J]. Chinese Journal of Magnetic Resonance,2006,23(3):379−395

[33] 张东明,胡千庭,袁地镜. 成型煤样瓦斯渗流的实验研究[J]. 煤炭学报,2011,36(2):288−292 ZHANG Dongming,HU Qianting,YUAN Dijing. An experiment research on gas seepage of standard coal briquette specimen[J]. Journal of China Coal Society,2011,36(2):288−292

[34] 高霞,赵宇贤,王柏琨,等. 颗粒形状对含瓦斯水合物煤体细观力学性质的影响[J]. 中国安全科学学报,2025,35(5):106−115 GAO Xia,ZHAO Yuxian,WANG Baikun,et al. Study on influence of particle shape on meso–mechanical properties of gas hydrate–bearing coal[J]. China Safety Science Journal,2025,35(5):106−115

[35] 吴建国. 基于马氏距离度量的聚类集成算法研究[D]. 太原：山西大学，2023. WU Jianguo. Research on the clustering ensemble algorithm based on the Mahalanobis distance metric[D]. Taiyuan：Shanxi University，2023.

[36] 袁亮,汤皓朋,马衍坤,等. 我国煤岩动力灾害模拟试验仪器研制现状与关键难题[J]. 煤田地质与勘探,2026,54(5):1−18 YUAN Liang,TANG Haop·eng,MA Yankun,et al. Instruments for simulation experiments on coal-rock dynamic disasters in China:Current status and key challenges[J]. Coal Geology & Exploration,2026,54(5):1−18

[37] 卢义玉,彭子烨,夏彬伟,等. 深部煤岩工程多功能物理模拟实验系统:煤与瓦斯突出模拟实验[J]. 煤炭学报,2020,45(增刊1):272−283 LU Yiyu,PENG Ziye,XIA Binwei,et al. Coal and gas outburst multi–functional physical model testing system of deep coal petrography engineering[J]. Journal of China Coal Society,2020,45(Sup.1):272−283

[38] 郝忠,蹇开林,彭守建,等. 煤与瓦斯突出过程中瓦斯流动规律的理论模型及数值解法[J]. 煤炭学报,2020,45(增刊2):833−840 HAO Zhong,JIAN Kailin,PENG Shoujian,et al. Theoretical model and numerical method on the law of gas flow in coal and gas outburst[J]. Journal of China Coal Society,2020,45(Sup.2):833−840

Download Chinese Version

Share

COinS
 
 

To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.