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国际煤炭科学技术学报（英文）
国际煤炭科学技术学报（英文）

季刊

2095-8293

国际煤炭科学技术学报（英文）/Journal International Journal of Coal Science & TechnologyCSCDCSTPCD北大核心
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    A review of coal permeability models including the internal swelling coefficient of matrix

    Shouqing LuJiang ShiLei JiaoYankun Ma...
    1-30页
    查看更多>>摘要：Coal bed methane(CBM),the high-quality and efficient fuel,has caught the interest of many nations as they strive for environmentally friendly development.Therefore,the efficient exploitation and utilization of CBM has become one of the international focal research problems.A significant factor affecting the mining of CBM is coal permeability.To better capture the changes that occur during the extraction of CBM,the internal swelling coefficient of matrix(ISCM)has been gradually in permeability introduced into the permeability models,and such models have become an important type of the development of permeability models.The goal is to find out more precisely the evolution mechanism of the ISCM and its influence on the permeability models.In this paper,the selection of coal structure,determination of boundary conditions and influencing factors of permeability for were first analyzed.Then,according to the research process of ISCM,the permeability models including the ISCM were reviewed and divided into four phases:proposal phase,development phase,evaluation phase and display of internal structure phase.On the basis of the ISCM values in the current coal permeability models,the primary influencing factors and evolutionary laws of the ISCM are explored.The results obtained provide guidance for future theo-retical refinement of permeability models with the ISCM.
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    Mechanical responses and fracturing behaviors of coal under complex normal and shear stresses,Part Ⅰ:Experimental results

    Z.Y.SongW.G.DangZ.C.BaiY.Zhao...
    31-58页
    查看更多>>摘要：This work presents experimental tests based on coal collected from a coal mine based underground water reservoir(CMUWR).The mechanical responses of dry and water-soaked coal samples under the complex normal and shear stresses under multi-amplitude and variable frequency is investigated.The experimental results reveal the effects of stress path,water soaking and frequency on deformation,energy dissipation,secant modulus and shear failure surface roughness.The experimental results show that when normal and shear stresses are applied simultaneously,there is a significant competi-tive relationship between them.On the dominant side,the strain rate will be significantly increased.The sample under a loading frequency of 0.2 Hz exhibits a longer fatigue life.During the cyclic shear test,the shear strain of the water-soaked sample is higher than that of the dry samples.The average roughness coefficient of failure surface exhibits an increasing pattern with increase in shear strength,the elevated roughness of a shear surface is advantageous in constraining shear displacements of specimens,thereby lowering the energy dissipation.This study can provide theoretical and practical implications for a long-term safety evaluation of CMUWR.
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    Mechanical responses and fracturing behaviors of coal under complex normal and shear stresses,Part Ⅱ:Numerical study using DEM

    Z.Y.SongF.AmannW.G.DangZ.Yang...
    59-84页
    查看更多>>摘要：This work presents particle-based numerical simulations on coal pillars in a coal mine based underground water reservoir(CMUWR).We aim to replicate the stress-strain characteristics and present the acoustic emission behavior of the coal under complex dynamic stress paths.The study reveals failure characteristics of coal exposed to monotonic/cyclic shear load under constant/cyclic normal loads.Based on the evolution of stress-time-dependent bond diameter implemented in particle model,different damage paths are established for dry and water-immersed samples under two loading frequencies.Furthermore,the numerical Gutenberg-Richter's b-value was calculated from the released energy emanating from bond failure,and this work presents the evolution of numerical Gutenberg-Richter's b-value.The numerical simulation contributes to a micromechani-cal understanding of the failure mechanisms of coal under water-immersion and cyclic stress,providing valuable insights for strength prediction of CMUWR.
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    Comparative study on different coals from the Lorraine basin(France)by sorption isotherms,thermogravimetric analysis and breakthrough curves for CO2-ECBM recovery

    Franck AmoihGisèle FinqueneiselThierry ZimnySandrine Bourrelly...
    85-103页
    查看更多>>摘要：The enhanced coalbed methane recovery using CO2 injection(CO2-ECBM)is widely proposed as a way of achieving the energy transition and reducing atmospheric CO2 in areas such as the Lorrain basin in France,where heavy industry is respon-sible for huge CO2 emissions and coal mines have been closed for more than a decade.This paper deals with the feasibility of extracting methane from the Lorraine basin using CO2-ECBM by comparing data from sorption isotherms,thermogravi-metric analyses and breakthrough curves for two coal samples.One is bituminous(Box 18),from Folschviller(France)and is compared with another sub-bituminous(TH01)from La Houve(France),which is used as a reference because it was identified as a good candidate for CO2-ECBM in a previous research program.The quantities of adsorbed gases(CO2/CH4)obtained by sorption isotherms,thermogravimetry and CO2 breakthrough curves showed that Box 18 adsorbs more CO2 and CH4 than TH01 due to its higher porosity and good affinity for gases(CO2/CH4).Tóth model fits the experimental CH4 and CO2 adsorption isotherms better,reflecting the fact that the adsorption surface of the coals studied is heterogeneous.Adsorp-tion enthalpies obtained by calorimetry indicated physisorption for gas-coal interactions,with higher values for CO2 than for CH4.Thermogravimetric analyses and breakthrough curves carried out at up to 50％relative humidity showed that the adsorption capacity of CO2 decreases with increasing temperature and the presence of water,respectively.The compilation of these experimental data explained the adsorption process of the studied coals and revealed their advantages for CO2-ECBM.
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    Geochemistry of Cenozoic coals from Sarawak Basin,Malaysia:implications for paleoclimate,depositional conditions,and controls on petroleum potential

    Lanre AsiwajuKhairul Azlan MustaphaWan Hasiah AbdullahSay Gee Sia...
    104-141页
    查看更多>>摘要：Forty Tertiary coals from Mukah-Balingian and Merit-Pila coalfields of the Sarawak Basin,Malaysia were investigated using bulk and molecular geochemical techniques such as proximate analysis,gas chromatography-mass spectrometry,elemental analyser,isotope ratio mass spectrometry,and inductively coupled plasma mass spectrometry to reconstruct their paleovegetation,paleoclimate,and environments of deposition.In addition,principal component analysis(PCA)of selected geochemical parameters was carried out to determine the controlling influences on the petroleum potential of the humic coals.δ13C values and the abundance of terpenoids imply the predominant contribution of angiosperms to the paleoflora.Bimetal proxies(Sr/Ba,Sr/Cu,and C-value),and δD values are generally suggestive of a warm and humid climate during the accu-mulation of the paleopeats.However,n-alkane proxies(Pwax,Paq,n-C23/n-C29,etc.)and polycyclic aromatic hydrocarbons(PAHs)distribution suggest that Balingian coals accumulated under relatively drier and strongly seasonal paleoclimate in the Late Pliocene.When compared with published global average abundances,the investigated coals are mostly depleted in major oxides and trace elements,suggesting peat accumulation in freshwater-influenced environments.Nonetheless,higher(＞0.5 wt％)total sulfur content in some Mukah-Balingian coals suggests some degree of epigenetic marine influence.Fur-thermore,the low to moderately-high ash contents of the Sarawak Basin coals indicate the presence of ombrotrophic and rheotrophic peat deposits.PCA result of selected geochemical proxies suggests that source input,paleoflora,and marine incursions are not major controlling influences on the petroleum potential.However,climatic,and depositional conditions appear to slightly influence the petroleum potential of the studied humic coals.
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    Research on coal-rock identification method and data augmentation algorithm of comprehensive working face based on FL-Segformer

    Yun ZhangLiang TongXingping LaiShenggen Cao...
    142-157页
    查看更多>>摘要：Coal-rock interface identification technology was pivotal in automatically adjusting the shearer's cutting drum during coal mining.However,it also served as a technical bottleneck hindering the advancement of intelligent coal mining.This study aimed to address the poor accuracy of current coal-rock identification technology on comprehensive working faces,coupled with the limited availability of coal-rock datasets.The loss function of the SegFormer model was enhanced,the model's hyperparameters and learning rate were adjusted,and an automatic recognition method was proposed for coal-rock interfaces based on FL-SegFormer.Additionally,an experimental platform was constructed to simulate the dusty environment during coal-rock cutting by the shearer,enabling the collection of coal-rock test image datasets.The morphology-based algorithms were employed to expand the coal-rock image datasets through image rotation,color dither-ing,and Gaussian noise injection so as to augment the diversity and applicability of the datasets.As a result,a coal-rock image dataset comprising 8424 samples was generated.The findings demonstrated that the FL-SegFormer model achieved a Mean Intersection over Union(MIoU)and mean pixel accuracy(MPA)of 97.72％and 98.83％,respectively.The FL-SegFormer model outperformed other models in terms of recognition accuracy,as evidenced by an MIoU exceeding 95.70％of the original image.Furthermore,the FL-SegFormer model using original coal-rock images was validated from No.15205 working face of the Yulin test mine in northern Shaanxi.The calculated average error was only 1.77％,and the model operated at a rate of 46.96 frames per second,meeting the practical application and deployment requirements in underground settings.These results provided a theoretical foundation for achieving automatic and efficient mining with coal mining machines and the intelligent development of coal mines.
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    The release and migration mechanism of arsenic during pyrolysis process of Chinese coals

    Meijie SunLingmei ZhouJiali ZhongYingjie Zhao...
    158-170页
    查看更多>>摘要：Special attention was drawn to the heavy metals contained in coal,due to it will cause harm to the environment during coal processing and utilization.The sequential chemical extraction of Shanxi coal(SX coal)and Wulanchabu coal(WLCB coal)was carried out to investigate the distribution of arsenic(As)in coals.Two raw coals were pyrolyzed at 300-900 ℃ in hori-zontal tubular furnace to investigate release behavior of As during pyrolysis process.The results showed that As in SX coal mainly existed in aluminosilicate-bound state(40.25％)and disulfide-bound state(32.51％),followed by carbonate-bound state and organic-bound state.The As in WLCB coal mainly existed in aluminosilicate-bound state(62.50％),followed by disulfide-bound state(19.10％).The As contents of water-soluble,ion-exchange and residue states in the two coals were less than others.The modes of occurrence of As had great influence on its volatilization behavior.As in organic part was easy to volatilize at low temperature.Sulfide-bound state would escape with the decomposition of pyrite.Because SX coal contained higher organic state and sulfide-bound state,the volatilization rate of As was higher than WLCB coal at any temperature,and the difference was more obvious at low temperature.In addition,FactSage simulation value was basically consistent with the experimental value.
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    Petrology and association of rare earth elements in magmatically altered high-ash coal of Indian origin

    Riya BanerjeeSaswati ChakladarAlok KumarShyamal Kumar Chattopadhyay...
    171-186页
    查看更多>>摘要：The extraction of valuables from waste has gained momentum.Thermal influence alters both the organic and inorganic components of coal.Insufficient knowledge on the association of rare earth elements(REEs)with the parent matrix of thermally altered high-ash coals(63％ash)limits the potential for such coals being utilized for isolation of valuables.In this study,we analyzed the distribution and occurrence modes of REEs within a magmatically altered high-ash coal via nine-step sequential extraction,combining Tessier and BCR methods.The total concentration of REEs in the coal sample,on whole coal basis,was found to be 820 ppm,which is significantly higher than the world average.Major mineral oxides were deduced to be those of Si,Fe,Al,Ca,Mg,and Ti.Sequential extraction confirmed that about 66％of HREE and 25％of LREE were included in the residual fraction.LREEs were concluded to be primarily in ionic form,whereas HREEs were speculated to be associated with the TiO2 phase.XRD analyses showed that thermal alteration affected the dolomite phase specifically,which selectively got removed where carbonate-bound elements were assessed.Petrographic analysis supported the magmatic influence and demonstrated the presence of mosaic structures and pores containing unfused vitrinite,with a reflectance value of 3.6.To summarize,the present study pertaining to delineation of association of valuables in high-ash heat-altered coals from an Eastern coalfield in India can potentially open up new avenues for utilizing such coals,which are otherwise considered waste.
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    Numerical simulation of adsorption process of O2/H2O mixed gas in coal porous media

    Huiyan GuoHongxiang ZhouChang GuoRongshan Nie...
    187-199页
    查看更多>>摘要：It is of great significance for coal mining and utilization to study the adsorption process of mixed gas in coal.In this paper,the Monte Carlo method(MC)is employed to study the competitive saturation adsorption of oxygen and water vapor inside coal particles,and then the convection,diffusion and adsorption inside and between particles are studied by lattice Boltzmann method(LBM).In addition,this study examines the impacts of porosity,average particle size,and gas concentration on the process of adsorption in coal porous media.The research results show that oxygen and water vapor present in the mixed gas experience increased permeability,diffusion rate,and saturated adsorption capacity as the porosity and average particle size of the coal porous medium increase.However,the time required to achieve saturated adsorption decreases.Under the condi-tion of maintaining the proportion of gas components and altering the initial gas concentrations from 4.087 to 53.131 mol/m3,saturated adsorption capacity of both gases remains nearly unchanged.Yet,the effective diffusivity of gases declines with increasing initial concentration.Additionally,it is also found that water vapor diffuses more quickly than oxygen in the mixed gas and achieves adsorption saturation faster.
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    Optimizing open-pit coal mining operations:Leveraging meteorological conditions for dust removal and diffusion

    Zhiming WangWei ZhouIzhar Mithal JiskaniJunlong Yan...
    200-215页
    查看更多>>摘要：Dust pollution from Chinese open-pit coal mines(OPCMs)threatens the coexistence of resource development and environ-mental protection.This research introduces a new approach to designing OPCMs based on meteorological indicators for dust removal and diffusion.It analyzes the production,distribution,and dust emission features of large-scale OPCMs in China.The factors affecting dust dispersion and atmospheric pollution characteristics were also examined.The findings reveal a surge in the number and output of OPCMs,intensifying the conflict between resource development and environmental protection.Notably,over 80％of OPCMs are in arid and semi-arid regions,exacerbating the challenge.Microclimate effects,including circulation and inversion effects,further amplify dust pollution.Regional and seasonal dust pollution patterns were identified,with the southern region experiencing the highest pollution levels,followed by the northern and central regions.Season-ally,dust pollution exhibits the following pattern:winter＞autumn＞spring＞summer.An alarming decline in atmospheric self-cleaning capacity over the past two decades underscores the pressing challenges ahead for dust control.The increase in air stagnation days/events highlights the urgency for effective dust prevention and control measures.This research suggests considering meteorological elements in OPCM design for dust control.Optimizing mining operations based on weather forecasts enables the utilization of natural conditions for effective dust prevention and control.The results provide insights for dust prevention and control in open-pit mines to foster green and climate-smart mining.
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