氧体积分数影响煤低温氧化动力学参数实验

Experimental of effect of oxygen concentration to coal low-temperature oxidation kinetics parameters

为研究氧体积分数对煤低温氧化反应的影响,对1.25～7mm混合粒径的煤样在5%～21%的氧体积分数条件下进行煤低温程序升温实验,并使用气相色谱仪测得出口气体氧体积分数,得出不同氧体积分数条件下煤在不同温度时的耗氧速率RO2,进而计算得到煤低温氧化反应的指前因子A值和表观活化能Ea值,分析了氧体积分数与耗氧速率RO2、指前因子A及表观活化能Ea三个特征值的关系.结果表明:氧体积分数影响耗氧速率大小,但不改变其随温度变化趋势;氧体积分数不能明显改变活化能的大小,对煤氧化反应的难易作用不大,但对煤的氧化反应速率有明显影响,且随氧体积分数升高影响逐渐减弱.

To study the influence of oxygen concentration to coal low-temperature oxidation,the temperatureprogrammed experiment was designed for mixed coal samples with particle size of 1.25 mm to 7 mm under the oxygen concentration between 5% and 21%,the oxygen concentration of outlet gas was measured by Gas Chromatograph,oxygen consumption rates under different oxygen concentration and temperature were drawn,the apparent activation energy(Ea)and pre-exponential factor(A) were calculated,and the relationship between oxygen concentration and Ea、A、RO2 was analyzed.The results show that RO2 is affected by oxygen concentration,but RO2 tendency following temperature is not changed; Ea is not obviously affected by oxygen concentration,which is with little effect to the difficulty of coal oxidation reaction,however,it is of obviously effect to the reaction rate,and the effect is gradual with the increasing of oxygen concentration.