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利用热重试验对粒径小于0.2 mm的长焰煤煤粉进行了不同氧体积分数(21%、40%、50%、60%和80%)和升温速率(20℃/min、30℃/min、40℃/min、50℃/min和60℃/min)的25种工况下煤氧复合过程中热解特性的测定,分析了两种因素对各特征值的影响。结果表明:以热失重速率为基准,长焰煤在含氧气氛下的热解过程可分为失水失重阶段、氧化增重阶段及着火、燃烧和炭化3个阶段;通用着火特性指标越大,煤样燃烧特性越好,自燃点越小,煤样工业分析结果应与其实际生产过程中的自燃危险性相结合;升温速率不变时自燃点随氧体积分数上升而下降,而煤氧复合时间随氧体积分数上升呈现先降低再微弱增加的趋势;氧体积分数一定时自燃点随升温速率上升而上升,煤氧复合时间则随之下降。对自燃点及煤氧复合时间进行均值无量纲化,并将其与无量纲化升温速率进行拟合,决定系数(R~2)约为1.0;提出了煤氧复合难易程度参数(D),计算结果表明,即使自燃点随升温速率上升发生滞后,煤氧复合难度仍然减弱。
The effects of different oxygen concentration (21%, 40%, 50%, 60% and 80%) and heating rate (20 ℃ / min, 30 ℃ / min, 40 ℃ / min, 50 ℃ / min and 60 ℃ / min respectively. The effects of two factors on each eigenvalue were analyzed. The results show that the pyrolysis process of long-flame coal in oxygen-containing atmosphere can be divided into three stages: loss of hydration stage, oxidation and weight gain stage, ignition, combustion and carbonization. , The better the combustion characteristics of coal samples, the smaller the self-ignition point, the industrial analysis of coal samples should be combined with the risk of spontaneous combustion in the actual production process; spontaneous combustion point decreases with the increase of oxygen volume fraction while heating rate is constant, The time tends to decrease first and then weakly with the increase of oxygen concentration. When the oxygen volume fraction increases, the spontaneous ignition point increases with the increase of heating rate, and the recombination time of coal and oxygen decreases. The mean value of self-ignition point and coal-oxygen recombination time were normalized and fitted with the non-dimensional heating rate. The coefficient of determination (R ~ 2) was about 1.0. The degree of difficulty of coal- oxygen recombination (D) The calculation results show that even if the self-ignition point lags behind the increase of the heating rate, the recombination of coal and oxygen will still be difficult.