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期刊信息/Journal information

国际煤炭科学技术学报（英文）

出版周期：季刊

国际刊号：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

正式出版

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Moisture penetration and distribution characterization of hard coal:Aμ-CT study

Lihai TanTing RenLinming DouJian Sun...

216-224页

查看更多>>摘要：Moisture content of rock/coal can change its mechanical properties and absorption capacities,which can directly affect gas diffusivity,change the stress distribution and hence cause significant impacts on the overall gas or coal extraction process.Observation of the water penetration process and water distribution in the coal matrix will be beneficial for the understanding of the fluid-solid coupling mechanism in hydraulic fracturing,aquifer cracking and coal seam infusion.However,the observation of water penetration process and the determination of water distribution mode were hard to be non-destructively achieved as coal is a non-uniform,inhomogeneous and un-transparent material.μ-CT imaging,which is based on variation of X-ray attenuation related to the density and atomic composition of the scanned objects,enables a four-dimensional(spatial-temporal)visualise of the heterogeneous and anisotropic coal samples.The primary aim of this paper is extending the application of μ-CT imaging to explore the moisture penetration and distribution within coal sam-ples during water infusion process,which has been reported by very little literature.The working principle and procedures of CT imaging was firstly introduced.Then,the determination equation of moisture distribution based on density profile was established.The CT determined moisture content has been compared with weighting method for verification.The paper has demonstrated that μ-CT can be used for non-destructively imaging the moisture distribution within coal samples.

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Merging TROPOMI and eddy covariance observations to quantify 5-years of daily CH4 emissions over coal-mine dominated region

Wei HuKai QinFan LuDing Li...

225-237页

查看更多>>摘要：A simple and flexible mass balance approach was applied to observations of XCH4 from TROPOMI to estimate CH4 emis-sions over Shanxi Province,including the impacts of advective transport,pressure transport,and atmospheric diffusion.High-frequency eddy-covariance flux observations were used to constrain the driving terms of the mass balance equation.This equation was then used to calculate day-to-day and 5 km x 5 km grided CH4 emissions from May 2018 to July 2022 based on TROPOMI RPRO column CH4 observations.The Shanxi-wide emissions of CH4,126±58.8 ug/m2/s,shows a fat tail distribution and high variability on a daily time scale(the 90th percentile is 2.14 times the mean and 2.74 times the median).As the number of days in the rolling average increases,the change in the variation decreases to 128±35.7 ug/m2/s at 10-day,128±19.8 ug/m2/s at 30-day and 127±13.9 ug/m2/s at 90-day.The range of values of the annual mean emissions on coal mine grids within Shanxi for the years 2018 to 2022 was 122±58.2,131±71.2,111±63.6,129±87.1,and 138±63.4 ug/m2/s,respectively.The 5-year average emissions from TROPOMI are 131±68.0 ug/m2/s versus 125±94.6 ug/m2/s on the grids where the EDGAR bottom-up database also has data,indicating that those pixels with mines dominate the overall emissions in terms of both magnitude and variability.The results show that high-frequency observation-based campaigns can produce a less biased result in terms of both the spatial and temporal distribution of CH4 emissions as compared with approaches using either low-frequency data or bottom-up databases,that coal mines dominate the sources of CH4 in Shanxi,and that the observed fat tail distribution can be accounted for using this approach.

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Assessment of factors and mechanism contributing to groundwater depressurisation due to longwall mining

M.ChenC.ZhangI.CanbulatS.Saydam...

238-273页

查看更多>>摘要：Assessment of mining impact on groundwater is one of critical considerations for longwall extension and sustainability,how-ever usually constrained by limited data availability,hydrogeological variation,and the complex coupled hydro-mechanical behaviour.This paper aims to determine the factors and mechanism of groundwater depressurisation and identify knowledge gaps and methodological limitations for improving groundwater impact assessment.Analysis of dewatering cases in Aus-tralian,Chinese,and US coalfields demonstrates that piezometric drawdown can further lead to surface hydrology degrada-tion,while the hydraulic responses vary with longwall parameters and geological conditions.Statistical interpretation of 422 height of fracturing datasets indicates that the groundwater impact positively correlates to panel geometry and depth of cover,and more pronounced in panel interaction and top coal caving cases.In situ stress,rock competency,clay mineral infillings,fault,valley topography,and surface-subsurface water interaction are geological and hydrogeological factors influencing groundwater hydraulics and long-term recovery.The dewatering mechanism involves permeability enhance-ment and extensive flow through fracture networks,where interconnected fractures provide steep hydraulic gradients and smooth flow pathways draining the overlying water to goaf of lower heads.Future research should improve fracture network identification and interconnectivity quantification,accompanied by description of fluid flow dynamics in the high fracture frequency and large fracture aperture context.The paper recommends a research framework to address the knowledge gaps with continuous data collection and field-scale numerical modelling as key technical support.The paper consolidates the understanding of longwall mining impacting mine hydrology and provides viewpoints that facilitate an improved assessment of groundwater depressurisation.

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Experimental study on the influence of roadway shape on the evolution of outburst fluid static pressure

Jiang XuXiaomei WangLiang ChengShoujian Peng...

274-289页

查看更多>>摘要：To explore the static pressure dynamic disaster mechanism of coal-and-gas outburst(CGO)fluid,the self-developed multi-field coupling large-scale physical simulation test system of coal mine dynamic disaster was used to carry out gas outburst and CGO physical simulation tests in straight,L-shaped and T-shaped roadways.The influence of roadway shape on the evolution of static pressure was explored,and the role of pulverized coal in the process of static pressure dynamic disaster was clarified.The results indicated that the static pressure showed a fluctuating downward trend during the outburst process.When gas outburst,the middle and front parts of the roadway in the straight section roadway were the most serious areas of static pressure disasters in the three shapes of roadways.The duration and range of high static pressure disaster in L-shaped roadway were larger than those in T-shaped and straight roadways in turn.When CGO,the most serious area of static pres-sure disaster in L-shaped and T-shaped roadways moved backward to the middle of the straight section roadway,and there was a rebound phenomenon in the process of static pressure fluctuation decline,which showed the pulse characteristics of CGO.During the outburst,the static pressure dynamic disaster hazard of L-shaped roadway was higher than that of T-shaped roadway,and the static pressure at the bifurcation structure decayed faster than that at the turning structure,which indicated that T-shaped roadway was more conducive to the release of static pressure in roadway,thus reduced the risk of static pres-sure disaster.When gas outburst,the static pressure attenuation of the fluid in the roadway before and after the turning and bifurcation structure was greater than that of CGO.The peak static pressure and impulse of the fluid during gas outburst were 2 times and 4-5 times that of CGO respectively.The presence of pulverized coal reduced the attenuation of static pres-sure and the hazard of dynamic disaster,prolonged the release time of energy,and led to the change of the maximum static pressure disaster area.

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Facile construction of porous carbon fibers from coal pitch for Li-S batteries

Junzhuo GuoZhiping LeiHonglei YanWeidong Zhang...

290-298页

查看更多>>摘要：Coal pitch,an important by-product in the coal coking industry with a high output,is a low-cost and high-carbon yield precursor for the manufacturing of high-value carbon materials.Herein,N/O co-doped carbon fiber(CFCP),fabricated by electrospinning using pre-oxidized coal pitch as the precursor,was employed as the sulfur host for Li-S batteries.The presence of more pyrrolic N and graphic N in CFCP than carbon fiber made from polyacrylonitrile benefits the adsorption of lithium polysulfide and the battery's life.Sulphur-CFCP cathode(S@CFCP)exhibited excellent specific capacity and cyclability,with a specific capacity of 701.1 mAh/g and a low capacity decay rate of 0.088％per cycle over 200 cycles at 2.0 C,respectively.The high ion diffusion rate,low charge transfer resistance,and effective conversion of lithium polysulfides enable the high electrochemical performance of S@CFCP.

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Experimental study on pore structure evolution of thermally treated shales:implications for CO2 storage in underground thermally treated shale horizons

Bodhisatwa HazraDebanjan ChandraVikram VishalMehdi Ostadhassan...

299-319页

查看更多>>摘要：Extracting gas from unconventional shale reservoirs with low permeability is challenging.To overcome this,hydraulic fracturing(HF)is employed.Despite enhancing shale gas production,HF has drawbacks like groundwater pollution and induced earthquakes.Such issues highlight the need for ongoing exploration of novel shale gas extraction methods such as in situ heating through combustion or pyrolysis to mitigate operational and environmental concerns.In this study,thermally immature shales of contrasting organic richness from Rajmahal Basin of India were heated to different tem-peratures(pyrolysis at 350,500 and 650 ℃)to assess the temperature protocols necessary for hydrocarbon liberation and investigate the evolution of pore structural facets with implications for CO2 sequestration in underground thermally treated shale horizons.Our results from low-pressure N2 adsorption reveal reduced adsorption capacity in the shale splits treated at 350 and 500 ℃,which can be attributed to structural reworking of the organic matter within the samples leading to formation of complex pore structures that limits the access of nitrogen at low experimental temperatures.Consequently,for both the studied samples BET SSA decreased by～58％and 72％at 350 ℃,and～67％and 68％at 500 ℃,whereas average pore diameter increased by～45％and 91％at 350 ℃,and～100％and 94％at 500 ℃ compared to their untreated counterparts.CO2 adsorption results,unlike N2,revealed a pronounced rise in micropore properties(surface area and volume)at 500 and 650 ℃(～30％-35％and～41％-63％,respectively for both samples),contradicting the N2 adsorption outcomes.Scanning electron microscope(SEM)images complemented the findings,showing pore structures evolving from microcracks to collapsed pores with increasing thermal treatment.Analysis of the SEM images of both samples revealed a notable increase in average pore width(short axis):by～4 and 10 times at 350 ℃,～5 and 12 times at 500 ℃,and～10 and 28 times at 650 ℃ compared to the untreated samples.Rock-Eval analysis demonstrated the liberation of almost all pyrolyzable kerogen components in the shales heated to 650 ℃.Additionally,the maximum micropore capac-ity,identified from CO2 gas adsorption analysis,indicated 650 ℃ as the ideal temperature for in situ conversion and CO2 sequestration.Nevertheless,project viability hinges on assessing other relevant aspects of shale gas development such as geomechanical stability and supercritical CO2 interactions in addition to thermal treatment.

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Assessing the hazard of diesel particulate matter(DPM)in the mining industry:A review of the current state of knowledge

Sikandar AzamShimin LiuSekhar BhattacharyyaSiyang Zheng...

320-366页

查看更多>>摘要：In the confined spaces of underground mines,the exposure of over 10,000 miners in the U.S.to diesel exhaust and diesel particulate matter(DPM)is an occupational inevitability,particularly in metal and nonmetal mineral extraction.These workers routinely operate amidst diesel-powered equipment,often outdated and highly polluting,extracting resources such as limestone,gold,and salt.The acute health effects of such exposure are significant,leading to symptoms like headaches and flu-like conditions,with the impact being more pronounced in these closed work environments.This review scrutinizes DPM's hazard in the mining sector,consolidating the extant knowledge and exploring ongoing research.It encapsulates our understanding of DPM's physicochemical properties,existing sampling methods,health ramifications,and mitigation technologies.Moreover,it underscores the necessity for further study in areas such as the evolution of DPM's physicochemi-cal attributes,from its genesis at high-pressure,high-temperature conditions within diesel engines to its emission into the mine atmosphere.A key research gap is the intricate interaction of DPM with specific characteristics of the mine environ-ment—such as relative humidity,ambient temperature,the presence of other mineral dust,and the dynamics of ventilation air.These factors can significantly alter the physicochemical profile of DPM,influencing both its in-mine transport and its deposition behavior.Consequently,this can affect the respiratory health of miners,modifying the toxicity and the respiratory deposition of DPM particles.Identified research imperatives include(1)the advancement of instrumentation for accurate number measurement of DPM to replace or supplement traditional gravimetric methods;(2)the development of long-lasting,cost-effective control technologies tailored for the mining industry;(3)an in-depth investigation of DPM interactions within the unique mine microclimate,considering the critical components like humidity and other aerosols;and(4)understanding the differential impact of DPM in mining compared to other industries,informing the creation of mining-specific health and safety protocols.This review's findings underscore the urgency to enhance emission control and exposure prevention strategies,paving the way for a healthier underground mining work environment.

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A software for calculating coal mine gas emission quantity based on the different-source forecast method

Wei ZhaoHuzi DongJunchen RenYuan Yuan...

367-374页

查看更多>>摘要：The ability to predict gas emissions accurately is pivotal in managing gas control and ensuring safe mining operations.Exist-ing internationally acknowledged gas control and prediction software does not cater to the specific conditions in Chinese coal mines.Hence,this paper introduces an object-oriented programming method to design a software tool for calculat-ing the total gas emission quantity using the MATLAB application program designer runtime environment.The software incorporates an algorithm,data structure,framework,and module functions,all of which enable seamless integration and visualization of gas emission calculation software.This software tool mitigates the inefficiencies and inaccuracies associated with manual,different-source forecast methods.Based on the field data of the Hulonggou Coal Mine in Shanxi province,this technical software was used to predict the gas emission of the mine.The research results show that the predicted value of the technical software is close to the actual measured value.The differing estimates of the working face and coal mine output primarily account for the deviation between the tool's predicted gas emission value and the field-measured value.The underlying design logic of this technical software determines that it has good adaptability to mines with clear mining technology parameters and gas geological parameters.This study provides a valuable method for researchers and engineers seeking to improve gas emission calculation efficiency.

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