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Structure and deformation measurements of shallow overburden during top coal caving longwall mining

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International Journal of Mining Science and Technology 2017年第6期27卷 1081-1085页

作者： Li Sheng fan chaojun Luo Mingkun Yang Zhenhua Lan Tianwei Zhang Haifeng College of Mining Liaoning Technical University State and Local Joint Engineering Laboratory for Gas Drainage & Ground Control of Deep Mines Henan Polytechnic University State Key Laboratory of Coal Resources and Safe Mining China University of Mining & Technology Chengyi Coal Mine Inner Mongolia Yitai Coal Co.Ltd.

Mining induced pressures are strong and overburden failure areas are large in top coal caving longwall mining, which constrains high production and safety mining. By employing the combination of the full view borehole photography technique and the seismic CT scanner technique, the deformation and failure of overlying strata of fully mechanized caving face in shallow coal seam were studied and the failure development of overburden was determined. Results show that the full view borehole photography can reveal the characteristics of strata, and the seismic CT scanner can reflect the characteristics of strata between the boreholes. The combined measurement technique can effectively determine the height of fractured and caved zones. The top end of the caved zone in Yangwangou coal mine employing the top coal caving longwall mining was at the depth of 171 m and fractured zone was at the depth of 106-110 m. The results provide a theoretic foundation for controlling the overburden strata in the shallow buried top coal caving panel.

关键词： Top coal caving Shallow depth Overburden failure and deformation Full view borehole photography Seismic CT scanner

Reasonable start time of carbon dioxide injection in enhanced coalbed methane recovery involving thermal-hydraulic-mechanical couplings

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Frontiers of Earth Science 2023年第3期17卷 832-843页

作者： chaojun fan Lei YANG Bin XIAO Lijun ZHOU Haiou WEN Hao SUN College of Mining Liaoning Technical UniversityFuxin 123000China College of Safety Science and Engineering Liaoning Technical UniversityHuludao 125105China

Injection of gas (CO_(2)) into coal seams is an effective method to benefit from both CO_(2) geological storage and coalbed methane recovery. Based on the dual pore structure of coal mass, and the Weibull distribution of fracture permeability, a menmal-hydraulic-mechanical (THM) coupling mathematical model is proposed involving the non-isothermal adsorption of binary gases, dynamic gas diffusion between matrix and fractures, multiphase seepage, coal deformation, heat conduction and heat convection. This mathematical model is applied to study the process of CO_(2)-enhanced coalbed methane recovery (CO_(2)-ECBM). Results show that the CH4 content of CO_(2)-ECBM in coal seam decreases significantly when compared with that of regular drainage, and decreases rapidly in the early stage but slowly in the later stage. Coal seam permeability evolution is triggered by changes in gas adsorption/desorption, temperature and effective stress. For regular drainage, the early permeability shows a decreasing trend dominated by the increase of effective stress, while the later permeability shows an increasing trend dominated by the CH4 desorption caused shrinkage of coal matrix. For CO_(2)-ECBM, the permeability in coal seam generally shows a downward trend due to both matrix swelling induced by gas adsorption and thermal expansion, particularly near injection well. There appears an increased and delayed peak production rate of CH4. The CH4 production rate of CO_(2)-ECBM is always higher than that of regular drainage. The CH4 cumulative production and CO_(2) cumulative storage linearly increase with time, and the CH4 cumulative production of CO_(2)-ECBM increased by 39.2% in the duration of 5000 d compared with regular drainage. Reasonable CO_(2) injection starting time can overcome the issue of early CO_(2) breakthrough and ineffective increase of CH4 production. In the studied case, the optimal injection starting time is 2500 d. Compared with the simultaneous CH4 extraction and CO_

关键词： CO_(2)sequestration coalbed methane reasonable injection start time thermo-hydro-mechanical coupling model numerical simulation

Elimination mechanism of coal and gas outburst based on geo‑dynamic system with stress–damage–seepage interactions

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International Journal of Coal Science & Technology 2023年第4期10卷 47-61页

作者： Lingjin Xu chaojun fan Mingkun Luo Sheng Li Jun Han Xiang Fu Bin Xiao College of Mining Liaoning Technical UniversityFuxin 123000China Energy Business Department Shanxi Lu’an Chemical GroupChangzhi 046200China Resource Department Liaoning Geology Engineering Vocational CollegeDandong 118000China

Coal and gas outburst is a complex dynamic disaster during coal underground *** the disaster mechanism is of great signifcance for accurate prediction and prevention of coal and gas *** geo-dynamic system of coal and gas outburst is *** framework of geo-dynamic system is composed of gassy coal mass,geological dynamic environment and mining *** of stress–damage–seepage interaction for gassy coal mass is constructed to resolve the outburst elimination process by gas extraction with boreholes through layer in foor *** results show the occurrence of outburst is divided into the evolution process of gestation,formation,development and termination of geo-dynamic *** scale range of outburst occurrence is determined,which provides a spatial basis for the prevention and control of *** formation criterion and instability criterion of coal and gas outburst are *** formation criterion F1 is defned as the scale of the geo-dynamic system,and the instability criterion F2 is defned as the scale of the outburst *** to the geo-dynamic system,the elimination mechanism of coal and gas outburst—‘unloading+depressurization’is established,and the gas extraction by boreholes through layer in foor roadway for outburst elimination is *** the research case,when the gas extraction is 120 days,the gas pressure of the coal seam is reduced to below 0.4 MPa,and the outburst danger is eliminated efectively.

关键词： Coal and gas outburst Geo-dynamic system Stress–damage–seepage coupling Elimination mechanism Instability criterion Gas extraction

Highly reinforce the interface stability using 2-Phenyl-1H-imidazole-1-sulfonate electrolyte additive to enhance the high temperature performance of LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)/graphite batteries

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Journal of Energy Chemistry 2023年第5期80卷 10-22,I0001页

作者： Xin He Yiting Li Wenlian Wang Xueyi Zeng Huilin Hu Haijia Li Weizhen fan chaojun fan Jian Cai Zhen Ma Junmin Nan School of Chemistry South China Normal UniversityGuangzhou 510006GuangdongChina Guangzhou Tinci Materials Technology Co. Ltd.Guangzhou 510760GuangdongChina

This work develops 2-Phenyl-1H-imidazole-1-sulfonate(PHIS)as a multi-functional electrolyte additive for H2O/HF scavenging and film formation to improve the high temperature performance of LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)/graphite *** 450 cycles at room temperature(25℃),the discharge capacity retentions of batteries with blank and PHIS-containing electrolyte are 56.03%and 94.92%*** 230 cycles at high temperatures(45℃),their values are 75.30%and 88.38%*** enhanced electrochemical performance of the batteries with PHIS-containing electrolyte is supported by the spectroscopic characterization and theoretical *** is demonstrated that this PHIS electrolyte additive can facilitate the construction of the electrode interface films,remove the H2O/HF in the electrolyte,and improve the electrochemical performance of the *** work not only develops a sulfonate-based electrolyte but also can stimulate new ideas of functional additives to improve the battery performance.

关键词： LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)/graphite battery High temperature performance H_(2)O/HF scavenger 2-Phenyl-1H-imidazole-1-sulfonate Electrolyte additive

Eliminating H_(2)O/HF and regulating interphase with bifunctional tolylene-2,4-diisocyanate(TDI)additive for long life Li-ion battery

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Journal of Energy Chemistry 2024年第8期95卷 519-528,I0011页

作者： Xueyi Zeng Xiang Gao Peiqi Zhou Haijia Li Xin He Weizhen fan chaojun fan Tianxiang Yang Zhen Ma Xiaoyang Zhao Junmin Nan School of Chemistry South China Normal UniversityGuangzhou 510006GuangdongChina Guangzhou Tinci Materials Technology Co.Ltd. Guangzhou 510760GuangdongChina School of Environmental Engineering and Chemistry Luoyang Institute of Science and TechnologyLuoyang 471023HenanChina School of Geomatic and Environmental Engineering Henan Polytechnic InstituteNanyang 473000HenanChina

Lithium-ion batteries(LIBs)featuring a Ni-rich cathode exhibit increased specific capacity,but the establishment of a stable interphase through the implementation of a functional electrolyte strategy remains *** when the battery is operated under high temperature,the trace water present in the electrolyte will accelerate the hydrolysis of the electrolyte and the resulting HF will further erode the *** order to enhance the long-term cycling performance of graphite/LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)LIBs,herein,Tolylene-2,4-diisocyanate(TDI)additive containing lone-pair electrons is employed to formulate a novel bifunctional electrolyte aimed at eliminating H_(2)O/HF generated at elevated *** 1000 cycles at 25℃,the battery incorporating the TDI-containing electrolyte exhibits an impressive capacity retention of 94%at 1 *** contrast,the battery utilizing the blank electrolyte has a lower capacity retention of only 78%.Furthermore,after undergoing 550 cycles at 1 C under45℃,the inclusion of TDI results in a notable enhancement of capacity,increasing it from 68%to 80%.This indicates TDI has a favorable influence on the cycling performance of LIBs,especially at elevated *** analysis of the film formation mechanism suggests that the lone pair of electrons of the isocyanate group in TDI play a crucial role in inhibiting the generation of H_(2)O and HF,which leads to the formation of a thin and dense *** existence of this interphase is thought to substantially enhance the cycling performance of the *** work not only improves the performance of graphite/NCM811 batteries at room temperature and high temperature by eliminating H_(2)O/HF but also presents a novel strategy for advancing functional electrolyte development.

关键词： Graphite/LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)battery Tolylene-2 4-diisocyanate Long-cycling performance H_(2)O/HF eliminated additive

Research advances in enhanced coal seam gas extraction by controllable shock wave fracturing

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International Journal of Coal Science & Technology 2024年第3期11卷 1-31页

作者： chaojun fan Hao Sun Sheng Li Lei Yang Bin Xiao Zhenhua Yang Mingkun Luo Xiaofeng Jiang Lijun Zhou College of Mining Liaoning Technical UniversityFuxin123000China College of Safety Science and Engineering Liaoning Technical UniversityFuxin123000China Energy Business Department Shanxi Lu’an Chemical GroupChangzhi046200China

With the continuous increase of mining in depth,the gas extraction faces the challenges of low permeability,great ground stress,high temperature and large gas pressure in coal *** controllable shock wave(CSW),as a new method for enhancing permeability of coal seam to improve gas extraction,features in the advantages of high efficiency,eco-friendly,and low *** order to better utilize the CSW into gas extraction in coal mine,the mechanism and feasibility of CSW enhanced extraction need to be *** this paper,the basic principles,the experimental tests,the mathematical models,and the on-site tests of CSW fracturing coal seams are reviewed,thereby its future research directions are *** on the different media between electrodes,the CSW can be divided into three categories:hydraulic effect,wire explosion and excitation of energetic materials by detonating *** the process of propagation and attenuation of the high-energy shock wave in coal,the shock wave and bubble pulsation work together to produce an enhanced permeability effect on the coal *** stronger the strength of the CSW is,the more cracks created in the coal is,and the greater the length,width and area of the cracks *** repeated shock on the coal seam is conducive to the formation of complex network fracture system as well as the reduction of coal seam strength,but excessive shock frequency will also damage the coal structure,resulting in the limited effect of the enhanced gas *** the influence of ground stress,the crack propagation in coal seam will be *** difference of horizontal principal stress has a significant impact on the shape,propagation direction and connectivity of the CSW induced *** permeability enhancement effect of CSW is affected by the breakage degree of coal *** shock wave is absorbed by the broken coal,which may hinder the propagation of CSW,resulting in a poor effect of permeability *** arranging two a

关键词： Controllable shock wave Permeability enhancement Gas extraction Basic principle Experimental test Mathematical models On-site test

Coal and gas outburst prediction model based on principal component analysis and improved support vector machine

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Geohazard Mechanics 2023年第4期1卷 319-324页

作者： chaojun fan Xinfeng Lai Haiou Wen Lei Yang College of Mining Liaoning Technical UniversityFuxin123000China

In order to predict the coal outburst risk quickly and accurately,a PCA-FA-SVM based coal and gas outburst risk prediction model was *** component analysis(PCA)was used to pre-process the original data samples,extract the principal components of the samples,use firefly algorithm(FA)to improve the support vector machine model,and compare and analyze the prediction results of PCA-FA-SVM model with BP model,FA-SVM model,FA-BP model and SVM *** rate,recall rate,Macro-F1 and model prediction time were used as evaluation *** results show that:Principal component analysis improves the prediction efficiency and accuracy of FA-SVM *** accuracy rate of PCA-FA-SVM model predicting coal and gas outburst risk is 0.962,recall rate is 0.955,Macro-F1 is 0.957,and model prediction time is *** with other models,The comprehensive performance of PCA-FA-SVM model is better.

关键词： Coal and gas outburst Risk prediction Principal component analysis(PCA) Firefly algorithm(FA) Support vector machine(SVM)

低透气性煤层水力冲孔和抽采钻孔瓦斯治理模拟研究

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矿业安全与环保 2021年第1期48卷 11-16页

作者：李喜员荣海范超军中国平煤神马集团炼焦煤资源开发及综合利用国家重点实验室河南平顶山467000 平煤股份煤炭开采利用研究院河南平顶山467000 辽宁工程技术大学矿业学院辽宁阜新123000

为消除平煤十矿己15-16-24100工作面在准备和回采过程中的突出危险,精细化模拟研究了水力冲孔结合抽采钻孔的瓦斯治理过程。分析了瓦斯解吸、渗流及煤岩变形的相互作用,构建了煤层瓦斯运移应力-渗流耦合数学方程,采用有限元软件对其求解... 详细信息

为消除平煤十矿己15-16-24100工作面在准备和回采过程中的突出危险,精细化模拟研究了水力冲孔结合抽采钻孔的瓦斯治理过程。分析了瓦斯解吸、渗流及煤岩变形的相互作用,构建了煤层瓦斯运移应力-渗流耦合数学方程,采用有限元软件对其求解,通过数值模拟己15-16-24100工作面顺层钻孔、底板巷穿层钻孔、水力冲孔掩护风巷、机巷和开切眼掘进及本煤层回采全过程,研究瓦斯抽采对降低工作面突出危险性的影响,并结合现场监测结果对抽采效果进行验证。研究结果表明:对己15-16煤层进行“穿层钻孔+顺层钻孔+穿层水力冲孔”综合抽采瓦斯可有效降低己15-16-24100工作面在准备和回采过程中的突出危险。在该设计方案下,己15-16煤层中残存瓦斯压力值降为0.25~0.45 MPa,相应的煤层残存瓦斯含量降为2.8~4.5 m^3/t,均满足平煤十矿煤与瓦斯突出防治规定要求。

关键词：低透气性煤层瓦斯治理应力—渗流耦合立体抽采水力冲孔精细化模拟

CH_4与N_2,CO_2间竞争吸附关系的核磁共振实验研究

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煤炭学报 2018年第2期43卷 490-497页

作者：罗明坤李胜荣海范超军杨振华辽宁工程技术大学矿业学院辽宁阜新123000 河南理工大学深井瓦斯抽采与围岩控制技术国家地方联合工程实验室河南焦作454003 辽宁工程技术大学煤炭资源安全开采与洁净利用工程研究中心辽宁阜新123000

利用核磁共振(NMR)技术测试了CH_4与CO_2,N_2在煤样中相互作用过程的NMR信号,并通过T_2谱形态和谱面积对各气体间相互作用的整个过程进行了描述和分析。测试结果表明:CH_4在煤中吸附过程的T_2谱呈双峰结构,弛豫时间较小的为吸附峰,另一... 详细信息

利用核磁共振(NMR)技术测试了CH_4与CO_2,N_2在煤样中相互作用过程的NMR信号,并通过T_2谱形态和谱面积对各气体间相互作用的整个过程进行了描述和分析。测试结果表明:CH_4在煤中吸附过程的T_2谱呈双峰结构,弛豫时间较小的为吸附峰,另一个为游离峰。随着吸附时间和注入压力的增加,吸附总量逐渐增加,但吸附速率逐渐降低。强吸附性气体能置换煤中已吸附的弱吸附性气体,反之效果不明显;置换过程中,大孔隙内的气体比小孔隙内的更容易置换。将弱吸附性气体注入已吸附强吸附性气体的煤中,一定程度上能促使原气体由吸附态向游离态转化;同时,少量的弱吸附性气体也能被吸附,气压越大越明显。NMR测试结果直观反映了CH_4与各气体间的相互作用关系。

关键词：核磁共振吸附解吸置换作用增产措施