煤低温氧化热解的热分析实验研究

在热分析动力学的基础上,对阳泉煤样运用同步热分析仪进行150℃下的氧化以及热解实验,得出该煤样相应的TG-DSC曲线。通过两者的TG-DSC曲线,对比分析煤样的热量释放情况,并结合曲线设定多项式形式的机理函数以分析其动力学特性。实验研究得出:该煤的低温氧化过程较之热解过程是个明显的氧化放热过程;该煤低温氧化和热解过程的最佳机理函数都为多项式,并且相应过程中的TG曲线和DSC曲线适用于同一个机理函数,这与一般所定义的机理函数不同;热解过程较之氧化过程所需的表观活化能较大,相同条件下较易发生煤的氧化自燃。     

低温阶段程序升温法对煤氧化过程影响的研究

基于温控方式对煤氧化指标测试的重要性,采用自主研制的煤氧化模拟试验系统,通过与恒温测试法对比煤氧化升温过程中CO的生成量,研究低温阶段程序升温法对煤氧化过程的影响。结果表明:程序升温法能较好地表现出煤的氧化能力,但程序升温会造成煤样罐中温度场分布不均匀,温度梯度逐渐增大,煤体氧化程度不相同。低温条件下,程序升温法对煤氧化过程的影响总体上还比较小,且程序升温法采用程序控制温升,升温连续性好,操作简单,是一种可靠的温控方式,可以替代恒温测试法进行测试,有很好的应用价值。     

一种基于AHP-RS的组合权重确定方法

在多目标综合评价和决策的过程中,指标权重的确定是其中一个重要的环节。分析目前广泛应用的主观赋权法和客观赋权法各自存在的不足,提出一种兼顾专家经验和客观信息的综合赋权法。应用粗糙集理论对原始数据进行挖掘,在数据离散化的基础上,根据属性依赖度原理,经过属性值特征化建立客观判断矩阵,结合层次分析法中的主观判断矩阵,通过建立Lagrange函数来确定组合判断矩阵的权重。实例应用表明,该方法能提高决策的准确性,具有实用性和推广价值。     

煤矿企业脆弱性评估的AHP-RS组合权重法

在阐述脆弱性的研究现状、基本概念和评价模型的基础上,构建了脆弱性评价模型,并针对具体的煤矿企业应急管理体系进行脆弱性评估,列出脆弱性评估的具体指标体系。在综合考虑主、客观因素的影响条件下,运用AHP-RS组合权重法和均等权重法分别确定一级指标和二级指标的权重,得出脆弱性指数。进而分析了该矿区的脆弱性程度及具体指标在系统脆弱性中所占比重大小,为煤矿企业应急管理脆弱性评估提供了一种新的定量评估方法,有利于全面掌握煤矿企业突发事件应急管理能力。     

The effect of N2/CO2 blend ratios on the pyrolysis and combustion behaviors of coal particles: Kinetic and thermodynamic analyses

The aim of this work is to investigate the impact of various CO₂/N₂ ratios on coal pyrolysis and combustion properties and to provide theoretical guidance for better preventing and controlling coal spontaneous combustion in the goaf. The dynamic pyrolysis and combustion characteristics of DX coal were analyzed by using a thermal gravimetric analyzer (TGA) in a constant oxygen atmosphere with different CO₂/N₂ blend ratios. The Málek method combining Coats-Redfern and Achar methods was used to determine the most probable mechanism functions. CO₂ containing atmospheres increased characteristic temperatures, burnout rate, maximum mass loss rate and comprehensive combustion performance index compared to O₂/N₂ atmospheres. In stages I-III, a lower apparent activation energy was observed in O₂/CO₂ atmospheres. Apparent activation energy and enthalpy changes showed upward trends in the reaction stage (I→III→IV), whereas Gibbs free energy change and entropy change decreased. The dynamic pyrolysis and combustion of DX coal necessitated increased energy in environment with a CO₂/N₂ ratio of 4:6, revealing the optimal inhibitory effect on DX coal with this particular ratio.     

基于AHP-熵权法的输气站场区块风险因素权重确定方法研究

为合理地体现主、客观风险因素对输气站场安全状况的影响,综合运用AHP和熵权法在确定权重方面的优势,在充分尊重专家经验的基础上,最大限度地削弱了权重确定的主观性.针对输气站场设施种类繁多、数量巨大,且分布既相对独立,又相互联系的特点,以工艺流程单元为大致框架,并兼顾设施共性风险因素,将输气站场划分为了清管器收发区、计量区、压气区、阀组区、安全仪表系统区等10大风险区块,并重点关注各区块内关键设备在运行期间的风险因素,最终建立起了10大区块62小项的输气站场两级风险评价指标体系.权重确定过程利用yaahp层次分析法软件和Excel辅助计算,大大降低了数据处理的工作量,同时保证了计算结果的准确性.     

Correction model for CO detection in the coal combustion loss process in mines based on GWO-SVM

Accurate detection of CO gas is crucial to the prevention of coal combustion. Tuneable diode laser absorption spectroscopy (TDLAS) is a reliable method for CO detection during coal combustion. The influences of temperature and pressure cause changes in the line strength and linewidth of the index gases’ absorption spectra, leading to sizable measurement errors. To correct the distortion of the CO absorption spectrum caused by temperature and pressure fluctuation, a compensation model based on the grey wolf optimizer–support vector machine (GWO–SVM) was proposed. The results were compared with those of the single SVM, the back propagation neural network (BPNN), and multiple regression analysis (MRA). MRA was revealed to result in the lowest accuracy, which indicated that MRA is not ideal for compensation in TDLAS. The hyperparameter selection of the SVM had the disadvantages of randomness and blindness, which led to instability and large errors. The BPNN achieved better correction in the training stage, but severe overfitting occurred in the testing stage. The modified results revealed that the GWO–SVM model had higher accuracy and stability than the other models. It effectively inhibited the effects of temperature and pressure on the measured concentration and greatly improved the measurement accuracy. The equipment is thus suitable for CO gas detection with the aim to preventing coal combustion loss, and it can be further applied to loss prevention in other process fields.     

保护层开采被保护层膨胀变形分析方法

基于传统的膨胀变形特征分析多是对被保护层在法线方向上通过测量两个定点 的距离变化来表征,这种从“两个定点”距离变化角度分析膨胀变形的方法只考虑被保 护层在法线方向上的变形特征,不能反应出被保护层的横向变形。针对计算结果不能全 面、准确的反应煤岩体的膨胀变形特征问题,首次提出了保护层开采过程中被保护层膨 胀变形的“四个定点围域面积”分析方法,该方法通过面积膨胀变化分析被保护层膨胀 变形特征。研究分析了在开采实践和实验室中“四个定点围域面积”的监测方案、面积 分析计算方法和“四个定点围域面积”的合理尺度。以沙曲矿多煤层开采相似模拟为背 景,分析了不同尺度下“四个定点围域面积”分析法的精度。研究表明,“四个定点围 域面积”分析方法较“两个定点”分析方法精度更高,被保护层厚度1倍尺度围域内划 分的面积单元格越多,膨胀变形计算精度越高。     

区域生态安全演变机制与过程分析

提出基于隐患因素的区域生态安全概念,阐述了隐患因素的作用机制:触发传递机制越弱,控制响应机制越强,系统安全状态相对最好;触发传递机制越强,控制响应机制越弱,系统安全状态相对最差;触发传递机制越弱,控制响应机制越弱,系统安全状态中等;触发传递机制越强,控制响应机制也越强,系统安全状态中等。根据突发性隐患因素与渐发性隐患因素作用的动态变化,基于安全科学的“R-M”基本理论,分析了区域生态安全渐变—突变过程,渐变正相变过程,渐变—突变的突变过程,渐变—突变的正相变过程,突变过程,正相变过程。最后总结生态安全渐变和突变的方法研究,并提出进一步需要解决的问题。     

煤岩破落过程中螺旋滚筒的可靠性研究

为了研究采煤机螺旋滚筒的可靠性,以散体力学理论与刚柔耦合多体系统动力学理论为基础,利用EDEM软件,建立了采煤机截割部与煤壁耦合的离散元仿真模型,分析了牵引速度与装煤率之间的关系,提取了煤岩破落过程中螺旋滚筒的工作载荷并验证了其可靠性,通过ADAMS动力学仿真分析,并找出了滚筒在工作过程中的应力分布规律。研究表明:滚筒应力随着牵引速度的增大而增大,但装煤率出现先增大后减小的规律,在保证采煤机可靠性的前提下,牵引速度控制在8 m/min左右有较高的装煤率。     

Experimental study on the influence mechanism of gas seepage on coal and gas outburst disaster

By using the self-developed triaxial servo-controlled seepage equipment for thermo-fluid-solid coupling of coal containing gas and the self-developed coal and gas outburst simulation test device, experiments to study the influence mechanism of gas seepage on coal and gas outburst disasters. The results show that: (i) gas seepage decreases the strength of coal containing gas and accelerates its failure process; (ii) under the same gas pressure, the confining pressure is larger, the more difficult the gas flows and the greater the intensity of coal containing gas is; (iii) in the process of coal and gas outburst, the greater the vertical ground stress is, the more powerful the outburst will be; (iv) the influence mechanism of gas seepage on coal and gas outburst disasters is as follows: firstly, gas seepage weakens the mechanical properties of coal body, which makes it much easier for coal and gas outburst to occur; secondly, on the same effect of external force, it will be easy to form a high gas pressure zone in the coal body under the difficult condition of gas seepage, and accumulate more gas compression energy, which is the energy source for coal and gas outburst, and it is also the main dynamic source to throw and grind the coal.