International Journal of Coal Science & Technology最新文献

{"title":"Comparative study on the flame retardancy of CO2 and N2 during coal adiabatic oxidation process","authors":"Xiyang Fang, Bo Tan, Haiyan Wang","doi":"10.1007/s40789-023-00652-y","DOIUrl":"https://doi.org/10.1007/s40789-023-00652-y","url":null,"abstract":"<p>To test the effectiveness of N₂ and CO₂ in preventing coal from spontaneously combusting, researchers used an adiabatic oxidation apparatus to conduct an experiment with different temperature starting points. Non-adsorbed helium (He) was used as a reference gas, and coal and oxygen concentration temperature variations were analyzed after inerting. The results showed that He had the best cooling effect, N₂ was second, and CO₂ was the worst. At 70℃ and 110℃, the impact of different gases on reducing oxygen concentration and the cooling effect was the same. However, at the starting temperature of 150℃, CO₂ was less effective in lowering oxygen concentration at the later stage than He and N₂. N₂ and CO₂ can prolong the flame retardation time of inert gas and reduce oxygen displacement with an initial temperature increase. When the starting temperature is the same, N₂ injection cools coal samples and replaces oxygen more effectively than CO₂ injection. The flame retardancy of inert gas is the combined result of the cooling effect of inert gas and the replacement of oxygen. These findings are essential for using inert flame retardant technology in the goaf.</p>","PeriodicalId":53469,"journal":{"name":"International Journal of Coal Science & Technology","volume":"191 1","pages":""},"PeriodicalIF":8.3,"publicationDate":"2023-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138528922","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":"Water–rock two-phase flow model for water inrush and instability of fault rocks during mine tunnelling","authors":"Dan Ma, Hongyu Duan, Qiang Li, Jiangyu Wu, Wen Zhong, Zhen Huang","doi":"10.1007/s40789-023-00612-6","DOIUrl":"https://doi.org/10.1007/s40789-023-00612-6","url":null,"abstract":"<p>Water inrush hazard is one of the major threats in mining tunnel construction. Rock particle migration in the seepage process is the main cause of water inrush pathway and rock instability. In this paper, a radial water–rock mixture flow model is established to study the evolution laws of water inrush and rock instability. The reliability of the proposed model is verified by the experimental data from a previous study. Through the mixture flow model, temporal-spatial evolution laws of different hydraulic and mechanical properties are analysed. And the proposed model’s applicability and limitations are discussed by comparing it with the existing water inrush model. The result shows that this model has high accuracy both in temporal evolution and spatial distribution. The accuracy of the model is related to the fluctuation caused by particle migration and the deviation of the set value. During the seepage, the porosity, permeability, volume discharge rate and volume concentration of the fluidized particle increase rapidly due to the particle migration, and this phenomenon is significant near the fluid outlet. As the seepage progresses, the volume concentration at the outlet decreases rapidly after reaching the peak, which leads to a decrease in the growth rate of permeability and porosity, and finally a stable seepage state can be maintained. In addition, the pore pressure is not fixed during radial particle migration and decreases with particle migration. Under the effect of particle migration, the downward radial displacement and decrease in effective radial stress are observed. In addition, both cohesion and shear stress of the rock material decreased, and the rock instability eventually occurred at the outlet.</p>","PeriodicalId":53469,"journal":{"name":"International Journal of Coal Science & Technology","volume":"35 1","pages":""},"PeriodicalIF":8.3,"publicationDate":"2023-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138528921","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":"Elimination mechanism of coal and gas outburst based on geo-dynamic system with stress–damage–seepage interactions","authors":"Lingjin Xu, Chaojun Fan, Mingkun Luo, Sheng Li, Jun Han, Xiang Fu, Bin Xiao","doi":"10.1007/s40789-023-00651-z","DOIUrl":"https://doi.org/10.1007/s40789-023-00651-z","url":null,"abstract":"<p>Coal and gas outburst is a complex dynamic disaster during coal underground mining. Revealing the disaster mechanism is of great significance for accurate prediction and prevention of coal and gas outburst. The geo-dynamic system of coal and gas outburst is proposed. The framework of geo-dynamic system is composed of gassy coal mass, geological dynamic environment and mining disturbance. Equations 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 floor roadway. The results show the occurrence of outburst is divided into the evolution process of gestation, formation, development and termination of geo-dynamic system. The scale range of outburst occurrence is determined, which provides a spatial basis for the prevention and control of outburst. The formation criterion and instability criterion of coal and gas outburst are established. The formation criterion <i>F</i>₁ is defined as the scale of the geo-dynamic system, and the instability criterion <i>F</i>₂ is defined as the scale of the outburst geo-body. According 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 floor roadway for outburst elimination is given. For 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 effectively.</p>","PeriodicalId":53469,"journal":{"name":"International Journal of Coal Science & Technology","volume":"8 1","pages":""},"PeriodicalIF":8.3,"publicationDate":"2023-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138528929","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 analysis of water-alternating-CO2 flooding for CO2-EOR and storage projects in residual oil zones","authors":"Boyu Liu, Jun Yao, Tunan Sun","doi":"10.1007/s40789-023-00647-9","DOIUrl":"https://doi.org/10.1007/s40789-023-00647-9","url":null,"abstract":"<p>Residual oil zones (ROZs) have high residual oil saturation, which can be produced using CO₂ miscible flooding. At the same time, these zones are good candidates for CO₂ sequestration. To evaluate the coupled CO₂-EOR and storage performance in ROZs for Water-Alternating-CO₂ (WAG) flooding, a multi-compositional CO₂ miscible model with molecular diffusion was developed. The effects of formation parameters (porosity, permeability, temperature), operation parameters (bottom hole pressure, WAG ratio, pore volume of injected water), and diffusion coefficient on the coupled CO₂-EOR and storage were investigated. Five points from the CO₂ sequestration curve and the oil recovery factor curve were selected to help better analyze coupled CO₂-EOR and storage. The results demonstrate that enhanced performance is observed when formation permeability is higher and a larger volume of water is injected. On the other hand, the performance diminishes with increasing porosity, molecular diffusion of gas, and the WAG ratio. When the temperature is around 100 °C, coupled CO₂-EOR and storage performance is the worst. To achieve optimal miscible flooding, it is recommended to maintain the bottom hole pressure (BHP) of the injection well above 1.2 minimum miscibility pressure (MMP), while ensuring that the BHP of the production well remains sufficiently high. Furthermore, the tapered WAG flooding strategy proves to be profitable for enhanced oil recovery, as compared to a WAG ratio of 0.5:1, although it may not be as effective for CO₂ sequestration.</p>","PeriodicalId":53469,"journal":{"name":"International Journal of Coal Science & Technology","volume":"54 1","pages":""},"PeriodicalIF":8.3,"publicationDate":"2023-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138528927","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":"Apparent activation energy of mineral in open pit mine based upon the evolution of active functional groups","authors":"Shipng Lu, Jingyu Zhao, Jiajia Song, Jiaming Chang, Chi-Min Shu","doi":"10.1007/s40789-023-00650-0","DOIUrl":"https://doi.org/10.1007/s40789-023-00650-0","url":null,"abstract":"","PeriodicalId":53469,"journal":{"name":"International Journal of Coal Science & Technology","volume":"100 3-4","pages":"1-15"},"PeriodicalIF":8.3,"publicationDate":"2023-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139262571","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":"Evaluation of roof cutting by directionally single cracking technique in automatic roadway formation for thick coal seam mining","authors":"Yubing Gao, Qiukai Gai, Xingxing Zhang, Xun Xi, Manchao He","doi":"10.1007/s40789-023-00642-0","DOIUrl":"https://doi.org/10.1007/s40789-023-00642-0","url":null,"abstract":"<p>Automatic roadway formation by roof cutting is a sustainable nonpillar mining method that has the potential to increase coal recovery, reduce roadway excavation and improve mining safety. In this method, roof cutting is the key process for stress relief, which significantly affects the stability of the formed roadway. This paper presents a directionally single cracking (DSC) technique for roof cutting with considerations of rock properties. The mechanism of the DSC technique was investigated by explicit finite element analyses. The DSC technique and roof cutting parameters were evaluated by discrete element simulation and field experiment. On this basis, the optimized DSC technique was tested in the field. The results indicate that the DSC technique could effectively control the blast-induced stress distribution and crack propagation in the roof rock, thus, achieve directionally single cracking on the roadway roof. The DSC technique for roof cutting with optimized parameters could effectively reduce the deformation and improve the stability of the formed roadway. Field engineering application verified the feasibility and effectiveness of the evaluated DSC technique for roof cutting.</p>","PeriodicalId":53469,"journal":{"name":"International Journal of Coal Science & Technology","volume":"3 1","pages":""},"PeriodicalIF":8.3,"publicationDate":"2023-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138528936","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":"Effect of CO2 dilution on laminar burning velocities, combustion characteristics and NOx emissions of CH4/air mixtures","authors":"Wenlong Dong, Longkai Xiang, Jian Gao, Bingbing Qiu, Huaqiang Chu","doi":"10.1007/s40789-023-00655-9","DOIUrl":"https://doi.org/10.1007/s40789-023-00655-9","url":null,"abstract":"Abstract The laminar combustion characteristics of CH 4 /air premixed flames with CO 2 addition are systemically studied. Experimental measurements and numerical simulations of the laminar burning velocity (LBV) are performed in CH 4 /CO 2 /Air flames with various CO 2 doping ratio under equivalence ratios of 1.0–1.4. GRI 3.0 mech and Aramco mech are employed for predicting LBV, adiabatic flame temperature (AFT), important intermediate radicals (CH 3 , H, OH, O) and NO x emissions (NO, NO 2 , N 2 O), as well as the sensitivity analysis is also conducted. The detail analysis of experiment and simulation reveals that as the CO 2 addition increases from 0% to 40%, the LBVs and AFTs decrease monotonously. Under the same CO 2 doping ratio, the LBVs and AFTs increase first and then decrease with the increase of equivalence ratio, and the maximum of LBV is reached at equivalence ratio of 1.05. The mole fraction tendency of important intermediates and NO x with equivalence ratio and CO 2 doping ratio are similar to the LBVs and AFTs. Reaction H + O 2 ⇔ O + OH is found to be responsible for the promotion of the generation of important intermediates and NO x under the equivalence ratios and CO 2 addition through sensitivity analysis. The sensitivity coefficients of elementary reactions that the increasing of CO 2 doping ratio promotes or inhibits formation of intermediate radicals and NO x decreases. Graphical abstract","PeriodicalId":53469,"journal":{"name":"International Journal of Coal Science & Technology","volume":"6 10","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136283983","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":"Simulation study of hydrogen sulfide removal in underground gas storage converted from the multilayered sour gas field","authors":"Yi Yang, Longxin Li, Xia Wang, Nan Qin, Ruihan Zhang, Yulong Zhao, Ye Tian","doi":"10.1007/s40789-023-00631-3","DOIUrl":"https://doi.org/10.1007/s40789-023-00631-3","url":null,"abstract":"Abstract A simulation study was carried out to investigate the temporal evolution of H 2 S in the Huangcaoxia underground gas storage (UGS), which is converted from a depleted sulfur-containing gas field. Based on the rock and fluid properties of the Huangcaoxia gas field, a multilayered model was built. The upper layer Jia-2 contains a high concentration of H 2 S (27.2 g/m 3 ), and the lower layer Jia-1 contains a low concentration of H 2 S (14.0 mg/m 3 ). There is also a low-permeability interlayer between Jia-1 and Jia-2. The multi-component fluid characterizations for Jia-1 and Jia-2 were implemented separately using the Peng-Robinson equation of state in order to perform the compositional simulation. The H 2 S concentration gradually increased in a single cycle and peaked at the end of the production season. The peak H 2 S concentration in each cycle showed a decreasing trend when the recovery factor (RF) of the gas field was lower than 70%. When the RF was above 70%, the peak H 2 S concentration increased first and then decreased. A higher reservoir RF, a higher maximum working pressure, and a higher working gas ratio will lead to a higher H 2 S removal efficiency. Similar to developing multi-layered petroleum fields, the operation of multilayered gas storage can also be divided into multi-layer commingled operation and independent operation for different layers. When the two layers are combined to build the storage, the sweet gas produced from Jia-1 can spontaneously mix with the sour gas produced from Jia-2 within the wellbore, which can significantly reduce the overall H 2 S concentration in the wellstream. When the working gas volume is set constant, the allocation ratio between the two layers has little effect on the H 2 S removal. After nine cycles, the produced gas’s H 2 S concentration can be lowered to 20 mg/m 3 . Our study recommends combining the Jia-2 and Jia-1 layers to build the Huangcaoxia underground gas storage. This plan can quickly reduce the H 2 S concentration of the produced gas to 20 mg/m 3 , thus meeting the gas export standards as well as the HSE (Health, Safety, and Environment) requirements in the field. This study helps the engineers understand the H 2 S removal for sulfur-containing UGS as well as provides technical guidelines for converting other multilayered sour gas fields into underground storage sites.","PeriodicalId":53469,"journal":{"name":"International Journal of Coal Science & Technology","volume":"24 16","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135774182","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":"Building 3D CityGML models of mining industrial structures using integrated UAV and TLS point clouds","authors":"Canh Le Van, Cuong Xuan Cao, Anh Ngoc Nguyen, Chung Van Pham, Long Quoc Nguyen","doi":"10.1007/s40789-023-00645-x","DOIUrl":"https://doi.org/10.1007/s40789-023-00645-x","url":null,"abstract":"Abstract Mining industrial areas with anthropogenic engineering structures are one of the most distinctive features of the real world. 3D models of the real world have been increasingly popular with numerous applications, such as digital twins and smart factory management. In this study, 3D models of mining engineering structures were built based on the CityGML standard. For collecting spatial data, the two most popular geospatial technologies, namely UAV-SfM and TLS were employed. The accuracy of the UAV survey was at the centimeter level, and it satisfied the absolute positional accuracy requirement of creating all levels of detail (LoD) according to the CityGML standard. Therefore, the UAV-SfM point cloud dataset was used to build LoD 2 models. In addition, the comparison between the UAV-SfM and TLS sub-clouds of facades and roofs indicates that the UAV-SfM and TLS point clouds of these objects are highly consistent, therefore, point clouds with a higher level of detail and accuracy provided by the integration of UAV-SfM and TLS were used to build LoD 3 models. The resulting 3D CityGML models include 39 buildings at LoD 2, and two mine shafts with hoistrooms, headframes, and sheave wheels at LoD 3.","PeriodicalId":53469,"journal":{"name":"International Journal of Coal Science & Technology","volume":"145 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136104289","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 slip evolution of planar fractures subjected to cyclic normal stress","authors":"Kang Tao, Wengang Dang, Xian Liao, Xingling Li","doi":"10.1007/s40789-023-00654-w","DOIUrl":"https://doi.org/10.1007/s40789-023-00654-w","url":null,"abstract":"Abstract The frictional rupture mechanisms of rock discontinuities considering the dynamic load disturbance still remain unclear. This paper investigates the transitional behaviors of slip events happened on a planar granite fracture under cyclic normal stress with different oscillation amplitudes. The experimental results show that the activations of fast slips always correlate with unloading of normal stress. Besides, the intensive normal stress oscillation can weaken the shear strength which is recoverable when the normal stress return to constant. The rupture patterns are quantified by stress drop, slip length and slip velocity. With the effect of small oscillation amplitudes, the slip events show chaotic shapes, compared to the regular and predictable style under constant normal stress. When the amplitude is large enough, the big and small slip events emerge alternately, showing a compound slip style. Large amplitude of the cyclic normal stress also widens the interval differences of the slip events. This work provides experimental supports for a convincible link between the dynamic stress disturbance and the slip behavior of rock fractures.","PeriodicalId":53469,"journal":{"name":"International Journal of Coal Science & Technology","volume":"59 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136261552","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}