【作者】 刘刚；

【导师】 李贝；

【作者基本信息】 大连理工大学 ， 安全科学与工程， 2022， 硕士

【摘要】 采空区煤自燃及相关事故严峻,造成超40亿吨煤无法开采及数十亿经济财产损失。本文通过研究煤尘氧化自燃特性和微观反应机理,建立氧化自燃动力学模型,确定开敞空间和受限空间堆积煤尘自燃特性和氮气抑制效果,为堆积煤自燃防治提供理论基础。论文研究主要包括以下五点:(1)基于热重-傅里叶红外光谱-气相色谱质谱联合实验,确定煤尘氧化自燃过程主要包括蒸发吸氧增重、燃烧和燃尽阶段,并包含最大脱附温度(Ta)、最大质量温度(Tm)、点燃温度(Ti)、最大反应速率温度(Tp)和燃尽温度(Tb);利用KAS,Starink和Vyazovkin方法计算确定煤尘活化能为133.79-52.95 k J/mol;分析自燃过程气体反应官能团和生成路径,确定煤尘自燃微观链式循环反应机理。(2)引进差分进化算法替代遗传算法,分别改善模型计算精度4.8%和时间消耗12.7%;分析煤尘自燃过程特征和单歩、多步反应模型结果,基于模型重构思想,确定煤尘氧化自燃反应模型f(α)=(1–α)0.8913+(1–α)3.5487。(3)分析开敞空间堆积煤尘自燃特征参数及反应阶段特性;基于煤尘动力学氧化自燃机理与传热传质理论,构建堆积煤尘点火突变温度预测模型;确定热载条件对煤尘氧化自燃过程影响和建立堆积煤尘自燃风险性评价模型。(4)分析受限空间堆积煤尘自燃特征参数,确定堆积煤尘层内温度变化规律、热载条件与受限空间对煤尘自燃特性的影响;分析氮气抑制氛围下堆积煤尘自燃特性,基于层次分析法,利用特征温度、反应时间和气体指标确定氮气浓度对煤尘自燃抑制效果评价体系,Air-N2混合气N2混合比例超过60%抑制效果为high(70.2%),确定了氮气抑制堆积煤尘自燃机制。更多还原

【Abstract】 The serious accidents related with coal spontaneous combustion in coal goaf has led to waste of over 4 billion tons coal and loss of billions of yuan in economic.Hence,the reaction characteristics and microscopic reaction mechanism of coal was researched,and the kinetic reaction model was determined in this paper.Additionally,the reaction behaviour of accumulated coal dust on hot surface under open and closed space was analyzed,and the inhibitory mechanism of nitrogen on oxidation and combustion of coal was determined for prevention and treatment of coal spontaneous combustion accidents.The researching content and progress of this paper were listed as follows:The thermogravimetry-fourier transform infrared spectroscopy-gas chromatography and mass spectrometrometry（TG-FTIR-GC/MS）coupled experiments were conducted to analyze the characteristic parameters,including temperature and reaction stage,and calculate the apparent activation energy.The functional groups of self-ignition reactions was studied,the formation path of main index gases and microscopic cyclic reaction mechanism was determined.The differential evolution algorithm was introduced in non-linear kinetic model calculation to replace genetic algorithm due to its advantages in time cost and calculation accuracy,with 4.8%and 12.7%improvement in deviation and time-cost.The software Peak Fit was utilized to analyze the reaction behaviors of coal based on multi-step reaction mechanism.The comparison of application of single-step and multi-step reaction mechanism on describing coal reaction characteristics was completed to determine the optimal reaction model.The reaction model expression was determined based on the reaction model reconstruction.The reaction characteristic parameters and stage division was analyzed for accumulated coal dust on hot surface under open space.The temperature distribution trend of coal dust was studied by the temperature prediction model based on the reaction mechanism of coal and mass and heat transfer theory.The effect of hot surface temperature was determined by observing the variation trend of characteristic parameters.Combining the TG and hot surface experiments,the self-ignition risk evolution model of accumulated coal dust on hot surface was built and the risk of experimental sample was determined.Design and build the reaction characteristics studies apparatus for accumulated coal dust under closed space.The reaction characteristic parameters and stage division were analyzed,and the temperature distribution trend of coal under closed space was determined.Reaction characteristics comparison of coal dust on hot surface under open and closed space was completed to determine the effect of isolation on coal reaction behaviors.The reaction characteristics of coal dust under N₂ inhibitory atmosphere was analysed,and the effect of N₂ concentration was determined based on characteristic temperature,index gas and evaluation index of combustion status.The inhibitory mechanism of N₂ on coal self-ignition reaction was determined based on combustion triangle.更多还原