不同氧浓度下煤体低温氧化过程中物化参数变化规律研究

Variation of physicochemical parameters of coal during low temperature oxidation under different oxygen concentrations

为了探究矿井采空区不同氧浓度对煤低温氧化过程的微观特性影响规律,进行煤体在不同氧浓度下的低温氧化实验,通过BEL-MAX型全自动比表面/孔隙分析和蒸汽吸附仪及电子自旋共振波谱仪(ESR),得到不同氧浓度下煤体低温氧化过程中孔隙分布变化特征及自由基变化规律。实验表明:随着氧浓度及氧化温度增加,水分、挥发分、BET比表面积及自由基浓度呈阶段性变化,130℃之后,煤氧复合速度加快,水分及挥发分的不断降低使得煤体孔隙的发育,增加了氧与煤的活性表面接触面积,激活原本不活泼的原生自由基,参与反应并生成更多新的自由基,在200℃的升温区间内自由基浓度(21%)最大上升了12.77×1017/g。

In order to explore the effect of different oxygen concentrations in mine goaf on the microscopic characteristics of coal during low temperature oxidation process,we simulated coal oxidation at low temperature under different oxygen concentrations.Through BEL-Max automatic specific surface/pore analysis,steam adsorption instrument and electron spin resonance spectrometer(ESR),the change characteristics of pore distribution and free radicals during low temperature oxidation of coal under different oxygen concentrations were obtained.The experimental results show that with the increase of oxygen concentration and oxidation temperature,moisture,volatile matter,BET specific surface area and free radical concentration change in stages.After 130℃,the recombination rate of coal and oxygen is accelerated,and the continuous decrease of moisture and volatile matter leads to the development of coal pores,increases the active surface contact area between oxygen and coal,activates the original inactive primary free radicals,participates in the reaction and produces more new free radicals.In the heating range of 200℃,the concentration of free radicals(21%)increased by 12.77×1017/g.