Experiment study of optimization on prediction index gases of coal spontaneous combustion

The coal of Anyuan Mine has the characteristic of easy spontaneous combustion. Conventional method is difficult to predict it. Coal samples from this mine were tested in laboratory. The data obtained from laboratory determination were initialized for the value which was defined as "K". The ratio of each index gas and value of "K", and the ratio of combination index gases and value of "K", were analyzed simultaneously. The research results show that for this coal mine, if there is carbon monoxide in the gas sample, the phenomenon of oxidation and temperature rising for coal exists in this mine; if there is C_2H_4 in the gas sample, the temperature of coal perhaps exceeds 130 °C. If the coal temperature is between 35 °C and 130 °C, prediction and forecast for coal spontaneous combustion depend on the value of Φ(CO)/K mainly; if the temperature of coal is between 130 °C and 300 °C, prediction and forecast for coal spontaneous combustion depend on the value of Φ(C_2H_6)/Φ(C_2H_2) and Φ(C_2H_6)/K. The research results provide experimental basis for the prediction of coal spontaneous combustion in Anyuan coal mine, and have better guidance on safe production of this coal mine.

△P index with different gas compositions for instantaneous outburst prediction in coal mines

In this study we measured the △P(initial speed of gas emission) index with different gas concentrations of carbon dioxide(pure CO2,90% CO2+10% CH4,67% CO2+33% CH4,50% CO2+50% CH4,30% CO2+10% CH4 and pure CH4) of coal samples from the No.2 coal seam in the Yaojie Coal Mine,Gansu province,China.The effect of carbon dioxide concentration,gas composition,coal strength and particle size of coal samples on the △P index was investigated.The experimental results show that with gas of various compositions,the △P value of three samples were clearly different.The △P index of coal samples A,B and C(0.2～0.25 mm) were 4,6 and 7 with pure CH4 and 22,30 and 21 when pure CH4 was used.Carbon dioxide concentration affects the △P index markedly.The △P index increases with an increase in carbon dioxide concentration,especially for coal B.Hence,the △P index and K(another outburst index) values tested only with pure CH4 for prediction of the danger of outburst is not accurate.It is important to determine the initial speed of gas emission given the gas composition of the coal seam to be tested for exact outburst prediction.

The study of coal mine equipment’s comprehensive evaluation index system and evaluation method

Equipment management is one of the important parts of business administra- tion of coal. Most of coal mines take no account of their equipment management, and have no comprehensive and effective evaluation index system. Based on the analysis of the equipment evaluation measures of reform and the applications, the paper built up a comprehensive and effective evaluation index system of coal mine equipment, and im- proved the evaluation method with the use of fuzzy theory, analytic hierarchy process and entropy method.

Discussion of the indexes of nonoutburst coal seam upgrade and its corresponding critical values

In view of the measurement difficulties of indexes recommended by the 50Items Experience of Coal Mine Gas Prevention in the process of the nonoutburst coalseam upgrade, this paper took the No.8 coal seam of Huainan Mining Group as research object. Discussed the suitability of indexes and corresponding critical values, putforward method in determining the indexes and its critical values by analysis and investigation of the gas geological condition and the-spot tracking near position where anoutburst occurred combined with laboratory experiment, and established the indexesand its critical values of nonoutburst coal seam upgrade in No.8 coal seam of HuainanMining Group. The results show that it is suitable to take gas content and tectonic softcoal thickness easily to gain in routine production as primary upgrade indexes that itscritical values are 7.5 m^3/t and 0.8 m, respectively. In addition, takefvalue and Ap valueas auxiliary indexes.

Theoretical study on safety assessment indexes system of coal mines

The safety status of the coal mines is closely correlated with the operating status and its changes of the whole working system in the coal mines, and the safety system is the sub system of the whole production system. In this paper, based on the analysis of the complicacy of the safety sub system and its affecting factors, the theory basis of the indexes system of the safety assessment was studied, including the establishing principles of the indexes system , the structure of the indexes system, the determining methods of the assessment indexes. The complete indexes system was established for the safety assessment of the coal mines in the paper.

Prediction method for risks of coal and gas outbursts based on spatial chaos theory using gas desorption index of drill cuttings

Based on the evolution of geological dynamics and spatial chaos theory, we proposed the advanced prediction an advanced prediction method of a gas desorption index of drill cuttings to predict coal and gas outbursts. We investigated and verified the prediction method by a spatial series data of a gas desorption index of drill cuttings obtained from the II3112 coal roadway at the Shitai Mine. Our experimental results show that the spatial distribution of the gas desorption index of drill cuttings has some chaotic characteristics, which implies that the risk of coal and gas outbursts can be predicted by spatial chaos theory. We also found that a proper amount of sample data needs to be chosen in order to ensure the accuracy and practical maneuverability of prediction. The relative prediction error is small when the prediction pace is chosen carefully. In our experiments, it turned out that the optimum number of sample points is 80 and the optimum prediction pace 30. The corresponding advanced prediction pace basically meets the requirements of engineering applications.

Damage Model of Brittle Coal-Rock and Damage Energy Index of Rock Burst

Based on the mechanical experiment of brittle coal-rock and the damage mechanical theory, a damage model was established. Coal-Rock damage mechanical characteristic was researched. Furthermore, interior energy transformation mechanism of rock was analyzed from the point of view of damage mechanics and damage energy release rate of brittle coal rock was derived. By analyzing the energy transformation of rock burst, a new conception, damage energy index of rock burst, was put forward. The condition of rock burst was also established.

烟煤黏结指数测定实验技术分析及实验教学优化

为准确测定烟煤黏结指数,优化本科实验教学过程,基于国家标准分析测试步骤,从煤样制备、煤样混合与压块、焦化与转鼓实验等方面对实验误差进行全面评价,为精准高效测试烟煤黏结指数提供理论依据。从工程背景实际出发,探索将传统验证性实验教学变更为开放性实验,激发学生主观能动性,提升实验教学质量。

Constructing an assessment index system for strategic risk management in coal science and technology enterprises

Coal occupies a dominant position in China's national economy and is an essential energy source for future industrial development.To inform the efficient and sustainable development of the coal industry,this paper analyzes the sources of strategic risk for coal science and technology enterprises using 3 firstclass indicators,10 second-level indicators,and 37 observation points established through the existing research literature and experience.Moreover,in accordance to the obtained initial index data,the selected indicators have been tested and screened using reliability and membership degree analyses to remove redundant variables,avoid juxtaposition of risk factors at different levels,and reduce the influence of some tiny risk factors for enterprise strategic risk.Then,factor analysis of external environment factor sub-scale was carried out.Factors are extracted according to a standard characteristic value greater than 1.Variables with high coefficients are classified into one factor category;and finally,3 first-class indicators,8 second-level indicators,and 37 observation points are reconstructed.

煤的气化反应性与其组成的关系研究

为探究不同变质程度煤的气化反应性,采用下落式固定床反应器,以CO_(2)为气化剂,对11种不同变质程度煤的气化反应性进行了实验研究,考察了煤的气化反应性与挥发分、固定碳、碳含量及灰组成的相互关系。研究结果表明,在1 400℃下,11种不同变质程度煤的气化反应性仍有较为明显的差异,低变质程度煤的气化反应性远高于中/高变质程度煤的气化反应性,其完全气化反应所需时间和气化反应指数最大有7倍之差;从工业分析和元素分析看,挥发分、固定碳和碳含量与煤气化反应性均具有较好的相关性,相关系数为0.88以上;从灰组成分析看,碱性指数与煤气化反应性相关性较差。为此,可根据煤的挥发分、固定碳和碳含量等组成信息预测煤气化反应性的优劣,为煤气化应用提供参考。

Experimental Study on the Mechanical Parameters Relating to the Impact Tendency of Coal Sample

Coal burst remains one of the gravest safety risks that will be encountered in mining in the future, because the stress conditions will become more complex as mining depths increase. Various influencing elements exist, and varied geological and mining circumstances might result in diverse coal burst phenomena. The impact propensity of coal has variations as a result of the distinct physical and mechanical qualities of each. To identify the impact propensity of coal and then understand the rules of coal burst occurrence, laboratory tests can be conducted to identify the physical and mechanical parameters affecting coal samples. The mechanical properties, energy absorption, and energy dissipation characteristics of coal samples were examined experimentally in this paper using coal samples that were taken from the mine. On the basis of the evaluation of the impact inclination parameters for four fundamental coal samples, novel impact inclination indicators and the relationship between the fractures in the coal sample and the impact inclination parameters were discussed. The following are the key conclusions: 1) On-site samples of No. 15 coal from the Qi yuan Coal Mine were taken (15 s) and processed in accordance with the guidelines for the coal specimen impact inclination test. The accuracy of the specimen was sufficient for the test. 2) Analysis is done on the mechanical relevance and calculation techniques of the four fundamental coal sample impact tendency characteristics, dynamic failure time (DT), elastic strain energy index (WET), impact energy index (KE), as well as uniaxial compressive strength (RC). 3) Regarding the rock burst danger of rock samples, the potential use of the ratio of pre-peak and post- peak deformation modulus to Kλ and the residual elastic strain energy index CEF as the impact propensity indices of coal samples are discussed. It is possible to utilize two new impact propensity indices to evaluate the impact propensity of coal samples, according to test results that reveal a linear correlation between two new impact inclination indexes and four fundamental impact tendency indexes. 4) The statistical analysis of the crack ratio with the four impact propensity indicators after coal specimen failure, and the correlation among the crack ratio with the indicators, are both done. The findings indicate that the four impact propensity indicators have a linear relationship with the crack ratio of the coal sample surface cracks.

Experimental Study on the Mechanical Parameters Relating to the Impact Tendency of Coal Sample

Coal burst remains one of the gravest safety risks that will be encountered in mining in the future, because the stress conditions will become more complex as mining depths increase. Various influencing elements exist, and varied geological and mining circumstances might result in diverse coal burst phenomena. The impact propensity of coal has variations as a result of the distinct physical and mechanical qualities of each. To identify the impact propensity of coal and then understand the rules of coal burst occurrence, laboratory tests can be conducted to identify the physical and mechanical parameters affecting coal samples. The mechanical properties, energy absorption, and energy dissipation characteristics of coal samples were examined experimentally in this paper using coal samples that were taken from the mine. On the basis of the evaluation of the impact inclination parameters for four fundamental coal samples, novel impact inclination indicators and the relationship between the fractures in the coal sample and the impact inclination parameters were discussed. The following are the key conclusions: 1) On-site samples of No. 15 coal from the Qi yuan Coal Mine were taken (15 s) and processed in accordance with the guidelines for the coal specimen impact inclination test. The accuracy of the specimen was sufficient for the test. 2) Analysis is done on the mechanical relevance and calculation techniques of the four fundamental coal sample impact tendency characteristics, dynamic failure time (DT), elastic strain energy index (WET), impact energy index (KE), as well as uniaxial compressive strength (RC). 3) Regarding the rock burst danger of rock samples, the potential use of the ratio of pre-peak and post- peak deformation modulus to Kλ and the residual elastic strain energy index CEF as the impact propensity indices of coal samples are discussed. It is possible to utilize two new impact propensity indices to evaluate the impact propensity of coal samples, according to test results that reveal a linear correlation between two new impact inclination indexes and four fundamental impact tendency indexes. 4) The statistical analysis of the crack ratio with the four impact propensity indicators after coal specimen failure, and the correlation among the crack ratio with the indicators, are both done. The findings indicate that the four impact propensity indicators have a linear relationship with the crack ratio of the coal sample surface cracks.

单轴压缩下松软煤体波速演化与裂隙分布特征

为研究松软煤体超声波传播规律与破坏特征,选用型煤代替原煤,设定3条波速传播路径,运用MTS岩石力学实验机、PCI-Ⅱ声发射仪开展单轴压缩条件下煤体多路径波速同步监测试验,引入各向异性指数分析波速演化规律;选定3个横、纵向切面,采用CT扫描设备开展破坏特征观测试验,重构破坏后煤体细观几何结构,对比研究二维横纵切面裂隙分布差异性;探讨波速和三维裂隙体积的关系。结果表明:①随轴向应变的增加,平行、垂直加载方向及煤体平均波速均表现出先平稳后降低再平稳的基本规律,波速各向异性指数具有先平稳后增大再平稳的变化趋势;垂直加载方向波速最先下降,且降幅最大。②与纵向切面相比,破坏后煤体横向切面裂隙谱峰占比和裂隙分形维数均较大,裂隙密度较高,裂隙形态也较为复杂。③随裂隙体积的增大,破坏后煤体平均波速大致呈线性降低,单轴荷载作用下煤体内部裂隙扩展以平行加载方向为主,裂隙竖向线状扩展是造成各方向波速和横纵切面破坏特征差异性的主要原因。④与平行加载方向相比,采用垂直加载方向波速求得的损伤变量较大、评价煤体损伤破坏状态也更为可靠。现场采用声波评价煤体破坏状态时,将声波传播路径设置为垂直煤体受载(最大主应力)方向,有利于提高预测失稳事故的合理性。

陕北煤矿区采动地裂缝对土壤抗蚀性的影响规律研究

采动地裂缝作为黄河流域中游陕北煤矿区最突出且典型的采动损害问题,引发的水土流失效应已经不容忽视。为了研究采动地裂缝发育对周边土壤抗蚀性的影响,以陕北煤矿区内宽度分别为0~10,10~20,20~30 cm的采动地裂缝为研究对象,采集周边水平距离80 cm以内,垂直深度40 cm以浅的土壤,测定了土壤水稳性团聚体、微团聚体、无机黏粒、有机黏粒、物理性质类等14个国内外学者普遍关注的用于量化表征土壤抗蚀性的指标,采用层次分析法、敏感性分析和因子分析相结合的方法甄选出陕北采动地裂缝发育区土壤抗蚀性的重要量化指标,构建了陕北采动地裂缝发育区土壤抗蚀性综合指数模型。结果表明:①综合层次分析法、敏感性分析和因子分析,甄选确定>0.25 mm水稳性团聚体含量、平均重量直径、<0.001 mm细黏粒含量、土壤团聚度、土壤有机质含量5个指标作为量化表征陕北采动地裂缝发育区土壤抗蚀性的重要指标;②采动地裂缝会降低周围土壤的5个土壤抗蚀性重要指标,其中>0.25 mm水稳性团聚体含量变化最为明显;③根据土壤抗蚀性重要指标,基于因子分析原理构建了陕北采动地裂缝发育区土壤抗蚀性综合指数模型;④采动地裂缝会降低周围土壤的抗侵蚀综合能力,且该效应随着裂缝宽度的增大和水平距离的减小而增强,当距采动地裂缝的水平距离超过170 cm时,采动地裂缝对周围土壤抗侵蚀综合能力的负效应基本消失,其可作为陕北采动地裂缝发育区土壤侵蚀防控的关键区域。研究结果可为黄河中游陕北矿区水土流失的精准防控提供科学依据。

煤炭企业安全生产费用效率评价

为评估我国的煤炭企业安全生产费用效率,选用数据包络分析(DEA)方法,选取2012—2020年煤矿安全投入产出数据构建DEA模型,对煤炭企业每年的安全生产费用效率进行静态分析和评价;随后,利用Malmquist指数对煤炭企业安全生产费用效率作进一步动态分析研究。研究结果表明:从静态分析来看,纯技术效率呈负增长趋势是阻碍综合效率增长的主要原因,煤炭企业安全生产费用应占营业收入的4.23%;从动态分析来看,技术进步和技术效率的提高都会相应提高Malmquist指数,提高我国煤炭企业全要素生产率指数的关键是提高技术进步指数。研究结果可为煤炭企业规范使用安全生产费用提供参考。

开采保护层与预抽煤层瓦斯防突效果分析

为比较开采保护层与预抽煤层瓦斯防突效果,以1124(3)运顺开采保护层段和预抽煤层瓦斯段煤巷掘进为试验对象,统计了试验地点煤巷掘进期间残余瓦斯含量、钻屑瓦斯解吸指标K1、钻屑量等防突指标,采用假设检验方法推断了各防突指标是否有差别,分析了开采保护层段和预抽煤层瓦斯段各防突指标产生差别的原因,验证了开采保护层区域防突措施比预抽煤层瓦斯区域防突措施更加安全可靠。

基于聚类算法的动力用煤资源质量评价方法与应用研究

为了快速、准确评价淮南煤田动力用煤资源的等级,达到合理开发利用优质动力用煤资源的目的,基于淮南煤田钻孔煤质大数据库,选取8煤层作为研究对象,将煤的发热量、灰分、硫分、挥发分、软化温度和哈氏可磨性作为动力用煤资源质量评价的基础指标。基于GIS平台,利用ISODATA算法对研究区动力用煤资源进行聚类,深入挖掘煤质数据信息。结合熵权法确定出每一簇类评价指标的权重,通过综合指数法实现动力用煤资源优劣等级的划分。研究结果表明,淮南煤田8煤层动力用煤资源聚类可分为三类,第二簇类动力用煤资源质量最好,其次为第三簇类,第一簇类质量相对较差。其中,第二簇类中优质煤占比最多,第三簇类以中质煤为主,第一簇类则以中质煤、低质煤为主。这为今后淮南煤田动力用煤资源合理开发利用提供了技术指导,并拓展了煤田煤质数据库的利用方式。

干燥温度对磨煤机出力的影响

煤的可磨性指数表征的是破碎煤的难易程度,影响到制粉系统能耗。通过一组干燥试验,研究了干燥强度对大同烟煤和元宝山褐煤的哈氏可磨性指数的影响规律,归集出干燥强度对哈氏可磨性指数影响趋势线。干燥对可磨性指数的影响不仅体现在水分的变化,干燥过程中会使煤的结构变化,也影响着可磨性指数。研究结果可以指导火电厂磨煤机运行中,各干燥介质风量组成及一次风温度等参数的调整。通过煤的干燥强度的调整,可以有效降低制粉系统的能耗。

2023-2024年中国煤炭产业经济形势研究报告

2023年,我国经济整体回升向好,煤炭产业继续落实能源保供任务,供需形势整体趋于宽松,价格同比有所下降,中矿(北京)煤炭产业景气指数整体呈现微幅下跌走势。展望2024年,煤炭需求有望在宏观经济复苏回暖的带动下,继续呈现增长趋势;受产量增速放缓、进口煤空间难以扩大影响,煤炭供给量增长将趋于放缓。总体看,2024年煤炭供需形势将呈现略微紧平衡态势,煤炭产业经济将继续保持稳中有进的发展趋势。在此背景下,短期内应继续提高我国煤炭增产保供能力,坚持创新发展,解决煤炭行业发展原动力问题,并关注煤炭与新能源的协同发展。