International Journal of Coal Science & Technology最新文献

{"title":"Investigation of ground subsidence response to an unconventional longwall panel layout","authors":"Pengfei Wang, Zhuang Zhu, Linfeng Guo, Huixian Wang, Yue Qu, Yaoxiong Zhang, Linwei Wang, Hua Wang","doi":"10.1007/s40789-024-00719-4","DOIUrl":"https://doi.org/10.1007/s40789-024-00719-4","url":null,"abstract":"<p>Ground subsidence caused by extraction of longwall panels has always been a great concern all over the world. Conventional longwall mining system (CLMS) gives rise to wavy subsidence causing great damage to surface structures. A coal mine in Shanxi, China, utilizes a split-level longwall layout (SLL) for a sub-horizontal No. 8 coal seam to improve the cavability of mudstone interlayer and top coal. This layout, however, also produced unexpectedly favorable surface subsidence. Subsidence of No. 6 and No. 8 longwall panels was monitored while mining was conducted. Field instrumentation and numerical simulation were carried out. It is demonstrated that an asymmetric subsidence profile with stepped subsidence and cracks occurred on the tailgate side but relatively mild and smooth deformation on the other. Due to elimination of conventional parallelepiped gate pillar, No. 6 and No. 8 gobs were connected. Extraction of two SLL panels acted as one supercritical panel. The maximum possible subsidence was reached which lowers the likelihood of potential future secondary subsidence as underground gob fractures and voids have closed. Therefore, SLL is more favorable for post-mining land reuse as gobs are more consolidated underground.</p>","PeriodicalId":53469,"journal":{"name":"International Journal of Coal Science & Technology","volume":"57 1","pages":""},"PeriodicalIF":8.3,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141934732","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Catalytic coal gasification: mechanism, kinetics, and reactor model","authors":"Weiwei Li, Chen Wang, Zhongliang Yu, Yuncai Song","doi":"10.1007/s40789-024-00712-x","DOIUrl":"https://doi.org/10.1007/s40789-024-00712-x","url":null,"abstract":"<p>Catalytic coal gasification is a promising technology in the field of clean coal utilization. A comprehensive understanding of mechanisms, reaction kinetic, and reactor model is crucial. This article summarizes and analyzes the catalytic mechanisms of key reactions, such as C–O₂, C–CO₂, C–H₂O, and CO–H₂. It also compares various kinetic models, including shrinking core model, random pore model, volume model and their respective modifications. Additionally, the article delves into mathematical modellings of catalytic coal gasification, encompassing molecular models or density functional theory, empirical model, computational fluid dynamics, Aspen modeling, and artificial neural network. The aim is to provide a roadmap for the development and scale up of reactors used in catalytic coal gasification.</p>","PeriodicalId":53469,"journal":{"name":"International Journal of Coal Science & Technology","volume":"85 1","pages":""},"PeriodicalIF":8.3,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141868106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study of synergistic behavior during bituminous coal-cow manure co-gasification: The role of intrinsic AAEM and organic matter","authors":"Hongqiao Lu, Meng Ma, Juntao Wei, Yonghui Bai, Peng Lv, Jiaofei Wang, Xudong Song, Guanghua Lu, Guangsuo Yu","doi":"10.1007/s40789-024-00694-w","DOIUrl":"https://doi.org/10.1007/s40789-024-00694-w","url":null,"abstract":"<p>Co-thermal chemical conversion of coal and biomass is one of the important ways to realize efficient and clean utilization of coal. In this study, a typical Ningdong coal-Yangchangwan bituminous coal and cow manure were used to study the synergistic effect of intrinsic alkali, alkaline earth metals (AAEM) and organic matter on the co-gasification of coal and biomass by thermogravimetry analyzer (TG). The results showed that AAEM had obvious synergistic promotion effect on the gasification of a bituminous coal-cow manure mixture in the isothermal gasification (1000 ℃), whereas the organic matter will show the opposite effect on the process. To further investigate the effect of organic matter on the gasification process, the influence of organic matter on non-isothermal (25-1000 ℃) gasification reaction was investigated with heating rate of 10 ℃ /min, the kinetic parameters of the gasification reaction were obtained by Coats-Redfern method. The increase of biomass mass fraction in the sample facilitates the migration of alkali metals from the material to the solid phase. The possible mechanism of the synergistic effect of intrinsic AAEM/organic matter on the co-gasification process was proposed.</p>","PeriodicalId":53469,"journal":{"name":"International Journal of Coal Science & Technology","volume":"73 1","pages":""},"PeriodicalIF":8.3,"publicationDate":"2024-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141785254","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Extractability and mineralogical evaluation of rare earth elements from Waterberg Coalfield run-of-mine and discard coal","authors":"Agnes Modiga, Orevaoghene Eterigho-Ikelegbe, Samson Bada","doi":"10.1007/s40789-024-00702-z","DOIUrl":"https://doi.org/10.1007/s40789-024-00702-z","url":null,"abstract":"<p>This study explores the extraction of rare earth elements (REEs) from high-ash run-of-mine and discard coal sourced from the Waterberg Coalfield. Three distinct methods were employed: (1) ultrasonic-assisted caustic digestion; (2) direct acid leaching; and (3) ultrasonic-assisted caustic-acid leaching. Inductively coupled plasma mass spectrometry was utilized to quantify REEs in both the coals and resultant leachates. Leaching the coals with 40% NaOH at 80 °C, along with 40 kHz sonication, yielded a total rare earth element (TREE) recovery of less than 2%. Notable enrichment of REEs was observed in the run-of-mine and discard coal by 17% and 19%, respectively. Upon employing 7.5% HCl, a recovery of less than 11.0% for TREE was achieved in both coal samples. However, leaching the caustic digested coal samples with 7.5% HCl significantly enhanced the TREE recovery to 88.8% and 80.0% for run-of-mine and discard coal, respectively. X-ray diffraction analysis identified kaolinite and quartz as the predominant minerals. Scanning electron microscopy-energy dispersive microanalysis revealed monazite and xenotime as the REE-bearing minerals within the coal samples. These minerals were found either liberated, attached to, or encapsulated by the clay-quartz matrices. Further mineralogical assessments highlighted the increased REE concentrations in coals post-caustic digestion and subsequent recovery during acid leaching. This increase was attributed to the partial dissolution of kaolinite encapsulating the RE-phosphates and the digestion of REE-bearing minerals. Notably, undissolved REE-bearing elements in the caustic-acid-leached coal indicated the necessity of harsh leaching conditions to augment REE recovery from these coal samples.</p>","PeriodicalId":53469,"journal":{"name":"International Journal of Coal Science & Technology","volume":"1 1","pages":""},"PeriodicalIF":8.3,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141785256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical simulation on the dynamic mechanical response and fracture mechanism of rocks containing a single hole","authors":"Zhenyu Han, Kai Liu, Jinyin Ma, Diyuan Li","doi":"10.1007/s40789-024-00718-5","DOIUrl":"https://doi.org/10.1007/s40789-024-00718-5","url":null,"abstract":"<p>Caverns and tunnels are constantly exposed to dynamic loads, posing a potentially significant threat to the safety of rock structures. To facilitate the understanding of dynamic fracture around openings, a series of discrete element models were established to numerically examine the effect of hole shape on dynamic mechanical properties and crack evolution. The results indicate that the existence of a hole greatly reduces dynamic strength, and the reduction is closely related to hole shape. The strain variation of pre-holed specimens is more complicated and even larger than the value of intact specimens. Although crack initiation differs for varying hole shapes, the entire structural collapse of specimens is controlled by macro shear cracks along the diagonal direction of the specimen, which are effectively identified by velocity trend arrows and contact force distribution. Finally, comparative analysis between failure pattern of pre-holed specimens under static and dynamic loads were conducted.</p>","PeriodicalId":53469,"journal":{"name":"International Journal of Coal Science & Technology","volume":"51 1","pages":""},"PeriodicalIF":8.3,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141744124","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mechanical responses and fracturing behaviors of coal under complex normal and shear stresses, Part I: Experimental results","authors":"Z. Y. Song, W. G. Dang, Z. C. Bai, Y. Zhao, P. T. Wang, Z. Yang","doi":"10.1007/s40789-024-00705-w","DOIUrl":"https://doi.org/10.1007/s40789-024-00705-w","url":null,"abstract":"<p>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 competitive 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.</p>","PeriodicalId":53469,"journal":{"name":"International Journal of Coal Science & Technology","volume":"40 1","pages":""},"PeriodicalIF":8.3,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141744125","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental study on pore structure evolution of thermally treated shales: implications for CO2 storage in underground thermally treated shale horizons","authors":"Bodhisatwa Hazra, Debanjan Chandra, Vikram Vishal, Mehdi Ostadhassan, Chinmay Sethi, Binoy K. Saikia, Jai Krishna Pandey, Atul K. Varma","doi":"10.1007/s40789-024-00717-6","DOIUrl":"https://doi.org/10.1007/s40789-024-00717-6","url":null,"abstract":"<p>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 temperatures (pyrolysis at 350, 500 and 650 °C) 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 ºC, 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 °C, and ∼67% and 68% at 500 °C, whereas average pore diameter increased by ∼45% and 91% at 350 °C, and ∼100% and 94% at 500 °C 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 ºC (∼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 °C, ∼5 and 12 times at 500 °C, and ∼10 and 28 times at 650 °C compared to the untreated samples. Rock-Eval analysis demonstrated the liberation of almost all pyrolyzable kerogen components in the shales heated to 650 °C. Additionally, the maximum micropore capacity, identified from CO₂ gas adsorption analysis, indicated 650 °C 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.</p>","PeriodicalId":53469,"journal":{"name":"International Journal of Coal Science & Technology","volume":"67 1","pages":""},"PeriodicalIF":8.3,"publicationDate":"2024-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141613679","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental study on the influence of roadway shape on the evolution of outburst fluid static pressure","authors":"Jiang Xu, Xiaomei Wang, Liang Cheng, Shoujian Peng, Hailin Yang, Bin Zhou, Feng Jiao","doi":"10.1007/s40789-024-00708-7","DOIUrl":"https://doi.org/10.1007/s40789-024-00708-7","url":null,"abstract":"<p>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 pressure 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 pressure 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 pressure and the hazard of dynamic disaster, prolonged the release time of energy, and led to the change of the maximum static pressure disaster area.</p>","PeriodicalId":53469,"journal":{"name":"International Journal of Coal Science & Technology","volume":"53 1","pages":""},"PeriodicalIF":8.3,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141587300","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Facile construction of porous carbon fibers from coal pitch for Li-S batteries","authors":"Junzhuo Guo, Zhiping Lei, Honglei Yan, Weidong Zhang, Zhan-Ku Li, Zhiming Du, Jingchong Yan, Hengfu Shui, Shibiao Ren, Zhicai Wang, Shigang Kang","doi":"10.1007/s40789-024-00711-y","DOIUrl":"https://doi.org/10.1007/s40789-024-00711-y","url":null,"abstract":"<p>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 (CF_CP), 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 CF_CP than carbon fiber made from polyacrylonitrile benefits the adsorption of lithium polysulfide and the battery’s life. Sulphur-CF_CP cathode (S@CF_CP) 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@CF_CP.</p>","PeriodicalId":53469,"journal":{"name":"International Journal of Coal Science & Technology","volume":"153 1","pages":""},"PeriodicalIF":8.3,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141587301","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessment of factors and mechanism contributing to groundwater depressurisation due to longwall mining","authors":"M. Chen, C. Zhang, I. Canbulat, S. Saydam, G. Fan, D. Zhang","doi":"10.1007/s40789-024-00716-7","DOIUrl":"https://doi.org/10.1007/s40789-024-00716-7","url":null,"abstract":"<p>Assessment of mining impact on groundwater is one of critical considerations for longwall extension and sustainability, however 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 Australian, Chinese, and US coalfields demonstrates that piezometric drawdown can further lead to surface hydrology degradation, 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 enhancement 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.</p>","PeriodicalId":53469,"journal":{"name":"International Journal of Coal Science & Technology","volume":"37 1","pages":""},"PeriodicalIF":8.3,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141587299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}