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Experimental Study on Seepage Characteristics of a Soil-Rock Mixture in a Fault Zone

Fluid Dynamics & Materials Processing 2022年第2期18卷 271-283页

作者： Pengfei Wang Xiangyang Zhang Key Laboratory of Safety and High-Efficiency coal Mining Ministry of EducationAnhui University of Science and TechnologyHuainan232001China School of Architecture and Civil Engineering Huangshan UniversityHuangshan245041China

A mixture of fault gouge and rubble taken out from a fault zone is used to prepare a S-RM(Soil-Rock Mixture)sample with rock block proportions of 20%,30%,40%,50%,60%and 70%,respectively.A GDS triaxial test system is used accordingly to measure the seepage characteristics of such samples under different loading and unloading confining pressures in order to determine the variation law of the permeability *** test results show that:(1)The permeability coefficient of the S-RM samples decreases as the pressure increases,and the decrease rate of this coefficient in the initial stage of confining pressure loading is obviously higher than in the semi-late period;(2)The permeability coefficient at different confining pressure levels presents a common trend as the rock block proportion is increased,i.e.,it decreases first then it increases(the permeability coefficient of the sample with rock block proportion 40%being the smallest,70%the largest);(3)In the stage of confining pressure unloading,the recovery degree of the permeability coefficient grows with the increase of rock block proportion(the recovery rate of S-RM sample with rock block proportion 70%reaches 50.2%);(4)In the stage of confining pressure loading and unloading,the sensitivity of the permeability coefficient to the rock block proportion displays the inverse“Z”variation rule(when rock block proportion reaches 60%,the sensitivity is highest);(5)In the stage of confining pressure loading,the relationship between the permeability coefficient and confining pressure can be described by an exponential relationship.

关键词： Fault zone rock block proportion soil-rock mixture confining pressure loading and unloading seepage characteristic

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A roughness parameter considering joint material properties and peak shear strength model for rock joints

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International Journal of Mining Science and Technology 2021年第3期31卷 413-420页

作者： Liren Ban Weisheng Du Tianwei Jin Chengzhi Qi Xiaozhao Li School of Civil and Transportation Engineering Beijing University of Civil Engineering and ArchitectureBeijing 100044China Deep Mining and Rock Burst Research Institute China Coal Research InstituteBeijing 100013China State Key Laboratory of coal Mining and Clean Utilization China Coal Research InstituteBeijing 100013China

This study aims at proposing a reasonable roughness parameter that can reflect the peak shear strength(PSS)of rock ***,the contribution of the asperities with different apparent dip angles to shear strength is *** the shear strength of the entire joint asperities is *** results showed that the PSS of the entire joint asperities is proportional to a key parameter hs,which is related to the geometric character of the joint surface and the joint material *** parameter hsis taken as the new roughness parameter,and it is reasonable to associate the PSS with the geometric characteristics of the joint *** on the new roughness parameter and shear test results of 20 sets of joint specimens,a new PSS model for rock joints is *** new model is validated with the artificial joints in this paper and real rock joints in published *** showed that it is suitable for different types of rock joints except for gneiss *** new model has the form of the Mohr-Coulomb model,which can directly reflect the relationship between the 3 D roughness parameters and the peak dilation angle.

关键词： Roughness Joint material properties Rock joints Peak shear strength Asperities

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Sponge Effect on coal Mine Methane Separation Based on Clathrate Hydrate Method

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Chinese Journal of Chemical Engineering 2011年第4期19卷 610-614页

作者： ZHANG Baoyong CHENG Yuanping WU Qiang National Engineering Research Center for coal Gas Control China University of Mining & Technology Xuzhou 221008 China Department of Safety Engineering Heilongjiang Institute of Science & Technology Harbin 150027 China

The findings were presented from laboratory investigations on the hydrate formation and dissociation processes employed to recover methane from coal mine *** separation process of coal mine methane(CMM) was carried out at 273.15K under 4.00 *** key process variables of gas formation rate,gas volume stored in hydrate and separation concentration were closely investigated in twelve THF-SDS-sponge-gas systems to verify the sponge effect in these hydrate-based separation *** gas volume stored in hydrate is calculated based on the measured gas *** CH4 mole fraction in hydrate phase is measured by gas chromatography to confirm the separation *** close examination of the overall results,it was clearly verified that sponges with volumes of 40,60 and 80 cm 3 significantly increase gas hydrate formation rate and the gas volume stored in hydrate,and have little effect on the CH4 mole fraction in hydrate *** present study provides references for the application of the kinetic effect of porous sponge media in hydrate-based *** will contribute to CMM utilization and to benefit for local and global environment.

关键词： coal mine methane separation clathrate hydrate sponge porous media mass transfer

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Pore structure of low‑permeability coal and its deformation characteristics during the adsorption–desorption of CH4/N2

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International Journal of coal Science & Technology 2023年第4期10卷 107-127页

作者： Pengfei Ji Haifei Lin Xiangguo Kong Shugang Li Biao Hu Pei Wang Di He Songrui Yang College of Safety Science and Engineering School of Safety Science and EngineeringXi’an University of Science and Technology58Yanta Mid.Rd.Xi’an 710054ShaanxiChina Key Laboratory of Western Mine Exploitation and Hazard Prevention Ministry of Education Xi’an University of Science and TechnologyXi’an 710054ShaanxiChina Western Engineering Research Centre of Mine Gas Intelligent Drainage for coal Industry Xi’an 710054ShaanxiChina

The pore structure of coal plays a key role in controlling the storage and migration of CH4/*** pore structure of coal is an important indicator to measure the gas extraction capability and the gas displacement efect of N2 *** deformation characteristic of coal during adsorption–desorption of CH4/N2 is an important factor afecting CH4 pumpability and N2 *** pore structure characteristics of low-permeability coal were obtained by fuid intrusion method and photoelectric radiation *** multistage and connectivity of coal pores were ***,a simultaneous test experiment of CH4/N2 adsorption–desorption and coal deformation was carried *** deformation characteristics of coal were clarifed and a coal strain model was ***,the applicability of low-permeability coal to N2 injection for CH4 displacement technology was *** results show that the micropores and transition pores of coal samples are relatively *** pore morphology of coal is dominated by semi-open *** pore structure of coal is highly complex and *** pores,mesopores and macropores of coal have good connectivity,while micropores have poor *** constant triaxial stress,the adsorption capacity of the coal for CH4 is greater than that for N2,and the deformation capacity of the coal for CH4 adsorption is greater than that for N2 *** axial strain,circumferential strain,and volumetric strain during the entire process of CH4 and N2 adsorption/desorption in the coal can be divided into three *** adsorption–desorption deformation has the characteristics of anisotropy and gas-diference.A strain model for the adsorption–desorption of CH4/N2 from coal was established by considering the expansion stress of adsorbed gas on the coal matrix,the compression stress of free gas on the coal matrix,and the expansion stress of free gas on micropore fractures.N2 has good injectability in

关键词： Low-permeability coal Pore structure Adsorption–desorption Deformation characteristics Strain model

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Diffusion and Reaction Model of Catalyst Pellets for Fischer-Tropsch Synthesis

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China Petroleum Processing & Petrochemical Technology 2013年第4期15卷 77-86页

作者： Wu Jianmin Sun Qiwen Zhang Zongsen Pang Lifeng Yankuang Energy R&D Co. Ltd. State Key Laboratory of Coal Liquefaction and Coal Chemical Technology

The diffusion and reaction phenomenon in a Fe-based catalyst pellet for Fischer-Tropsch synthesis was studied. It was considered that the pores of catalyst pellets were full of liquid wax under Fischer-Tropsch synthesis conditions. The re- actants diffused from the bulk gas phase to the external surface of the pellet, and then the reactants diffused through the wax inside the pellet and reacted on the internal surface formed along the pore passages of the pellet. On the basis of reaction kinetics and double a-ASF product distribution model, a diffusion and reaction model of catalyst pellet was established. The effects of diffusion and reaction interaction in a catalyst pellet, the bulk temperature, the reaction pressure and the pellet size on the reactivity were further investigated. The relationship between the internal diffusion effectiveness factor of spherical catalyst pellet and the Thiele modulus were also discussed. The bulk temperature and pellet size have significant effects on the reactivity, while the pressure shows only a slight influence on the reactivity. The internal diffusion effectiveness factor decreases with an increasing Thiele modulus.

关键词： Fischer-Tropsch synthesis diffusion and reaction catalyst pellet internal diffusion effectiveness factor

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Regulation of hydrogen evolution performance of titanium oxide-carbon composites at high current density with a Ti-O hybrid orbital

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Carbon Energy 2022年第3期4卷 480-490页

作者： Meichen Liu Zhiping Lei Qingping Ke Peixin Cui Jiancheng Wang Jingchong Yan Zhanku Li Hengfu Shui Shibiao Ren Zhicai Wang Ying Kong Shigang Kang Anhui Province Key Laboratory of coal Clean Conversion and High Valued Utilization Institute of Material Science&EngineeringSchool of Chemistry&Chemical EngineeringAnhui University of TechnologyMa'anshanChina Key Laboratory of Soil Environment and Pollution Remediation Institute of Soil ScienceThe Chinese Academy of SciencesNanjingChina Key Laboratory of coal Science and Technology Ministry of Education and Shanxi ProvinceTaiyuan University of TechnologyTaiyuanChina

Rational design and controllable synthesis of practical electrodes with high sta bility and activity at high current density for a hydrogen evolution reaction(HER)are critical for renewable and sustainable energy ***,high-performance TiO_(2)-based electrocatalysts for HER are quite limited,and the cat alytic active centers still remain ***,a simple strategy is demonstrated for the synthesis of TiO_(2)-carbon composite(TiO_(2)/C)with high HER performance and *** remarkable HER performance of TiO_(2)/C can be ascribed to the doping of carbon atoms,which leads to stronger hybridization of Ti 3d and O 2p orbitals,thus substantially improving the electrocatalytic *** study elucidates that the hydrogen evolution activity of oxide electrocatalysts can be largely improved by regulating their electronic structures by doping carbon atoms and also provides an effective strategy for designing heterostructured electro catalysts with high catalytic activity and stability at high current density for HER.

关键词： C doping HER high current density Ti-O hybridization TiO_(2)/C

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THERMO-CHEMICAL REACTIONS AND STRUCTURAL EVOLUTION OF ACRYLAMIDE-MODIFIED POLYACRYLONITRILE

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Chinese Journal of Polymer Science 2010年第3期28卷 367-376页

作者：吕春祥 Key Laboratory of Carbon Materials Institute of Coal ChemistryChinese Academy of Sciences

Thermal properties of acrylonitrile （AN）-acrylamide （AM） copolymers for carbon fibers were studied by DSC and in situ FTIR techniques in nitrogen （N2） and air flows. The cyclization mechanism and stabilization behavior of polyacrylonitrile （PAN） were discussed. In N2 flow, it was found that AM had the ability to initiate and accelerate cyclization process, which was confirmed by the fact that the initiation of nitriles shifted to a lower temperature. Compared to AN homopolymer, the initiation temperature of cyclization was ahead 32 K by introducing 3.59 mol% AM into the copolymer. The exothermic reaction was relaxed due to the presence of two separated exothermic peaks. Accompanied by DSC, in situ FTIR and calculation of activation energy, the two peaks were proved to be caused by ionic cyclization and free radical cyclization, respectively, and the corresponding cyclization mechanism was proposed. With increasing in AM content, the ionic cyclization tends to be dominant and the total heat liberated first increases and then decreases. For AN homopolymer, the activation energy of cyclization is 179 kJ/mol. For AN-AM copolymer （containing 3.59 mol% AM）, the activation energy of ionic cyclization is 96 kJ/mol and that of free radical cyclization is 338 kJ/mol. In air flow, similar cyclization routes occur and the difference is the contribution of oxidation. The oxygen in environment has no remarkable effect on cyclization of AN homopolymer but retards the cyclization of AN-AM copolymers. For AN-AM copolymer with 3.59 mol% AM, the cyclization temperature is postponed 10℃ in air.

关键词： Carbon fibers Acrylonitrile-acrylamide copolymers Thermal properties Activation energy Cyclization mechanism.

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An early warning method for water inrush in Dongjiahe coal mine based on microseismic moment tensor

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Journal of Central South University 2020年第10期27卷 3133-3148页

作者： MA Ke SUN Xing-ye TANG Chun-an WANG Su-jian YUAN Fu-zhen PENG Yi-lin LIU Kai State Key Laboratory of Coastal and Offshore Engineering Dalian University of TechnologyDalian 116024China Institute of Rock Instability and Seismicity Research Dalian University of TechnologyDalian 116024China Shannxi coal and Chemical Technology Institute Company limited Xi’an 710065China China Petroleum Pipeline Engineering Corporation Langfang 065000China School of Environmental Science University of LiverpoolLiverpool L693BXUnited Kingdom Department of Engineering Science University of OxfordParks RoadOX13PJUnited Kingdom

Dongjiahe coal Mine belongs to the Carboniferous Permian coal field which has a high degree of karst and fissure *** paper takes the working face of Dongjiahe coal Mine as an example;through the microseismic(MS)monitoring system arranged on the working face,the moment tensor theory was used to invert the focal mechanism solution of the anomalous area of the floor MS event;combining the numerical simulation and field data,the underlying floor faults were identified by the stress inversion *** results show that:1)Moment tensors were decomposed into three components and the main type of rupture in this area is mixed failure according to the relative criterion;2)The hidden fault belongs to the reversed fault,its dip angle is approximately 70°,and the rupture length is 21 m determined by the inversion method of the initial dynamic polarity and stress in the focal mechanism;3)The failure process of the fault is divided into three stages by numerical simulation method combined with the temporal and spatial distribution of MS *** results can provide a reference for early warning and evaluation of similar coal mine water inrush risks.

关键词： moment tensor inversion water inrush fault recognition realistic failure process analysis

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Assessment of coal gasification in a pressurized fixed bed gasifier using an ASPEN plus and Euler–Euler model

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International Journal of coal Science & Technology 2020年第3期7卷 516-535页

作者： Tamer M.Ismail Mingliang Shi Jianliang Xu Xueli Chen Fuchen Wang M.Abd El-Salam Mechanical Engineering Department Suez Canal UniversityIsmailiaEgypt Key Laboratory of coal Gasification and Energy Chemical Engineering of Ministry of Education East China University of Science and TechnologyShanghaiChina Shanghai Engineering Research Center of coal Gasification East China University of Science and TechnologyShanghaiChina Department of Basic Science Cairo UniversityGizaEgypt

With the help of Aspen Plus,a two-dimensional unsteady CFD model is developed to simulate the coal gasification process in a fixed bed gasifier.A developed and validated two dimensional CFD model for coal gasification has been used to predict and assess the viability of the syngas generation from coal gasification employing the updraft fixed bed *** process rate model and the sub-model of gas generation are *** particle size variation and char burning during gasification are also taken into *** order to verify the model and increase the understanding of gasification characteristics,a set of experiments and numerical comparisons have been carried *** simulated results in the bed are used to predict the composition of syngas and the conversion of *** model proposed in this paper is a promising tool for simulating the coal gasification process in a fixed bed gasifier.

关键词： Fixed bed gasifier Aspen plus Euler-Euler model coal

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Experimental and numerical study of failure behavior and mechanism of coal under dynamic compressive loads

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International Journal of Mining Science and Technology 2020年第5期30卷 613-621页

作者： Junjun Feng Enyuan Wang Qisong Huang Houcheng Ding Xiangyang Zhang Civil Engineering and Architecture Anhui University of TechnologyMaanshanAnhui 243002China Key Laboratory of Safety and High-efficiency coal Mining Ministry of EducationAnhui University of Science and TechnologyHuainanAnhui 232001China State Key Laboratory Cultivation Base for Gas Geology and Gas Control Henan Polytechnic UniversityJiaozuoHenan 454003China Key Laboratory of Gas and Fire Control for coal Mines China University of Mining and TechnologyXuzhouJiangsu 221116China

A comprehensive understanding of the failure behavior and mechanism of coal is a prerequisite for dealing with dynamic problems in mining *** this study,the failure behavior and mechanism of coal under uniaxial dynamic compressive loads were experimentally and numerically *** experiments were conducted using a split Hopkinson pressure bar(SHPB)*** results indicated that the typical failure of coal is lateral and axial at lower loading rates and totally smashed at higher loading *** further fractography analysis of lateral and axial fracture fragments indicated that the coal failure under dynamic compressive load is caused by tensile brittle *** addition,the typical failure modes of coal under dynamic load were numerically *** numerical results indicated that the axial fracture is caused directly by the incident compressive stress wave and the lateral fracture is caused by the tensile stress wave reflected from the interface between coal specimen and transmitted *** application was further conducted to interpret dynamic problems in underground coal mine and it manifested that the lateral and axial fractures of coal constitute the parallel cracks in the coal mass under roof fall and blasting in mining space.

关键词： Split Hopkinson pressure bar Stress wave Failure mode Fracture mechanism Fractography

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