不同自燃倾向性煤自燃氧化特性试验研究

Experimental study on oxidation characteristics of coal with different spontaneous combustion tendency

为了研究不同自燃倾向性煤自燃特性变化规律,利用煤氧化动力学测定系统,测试了三种不同自燃性煤的氧化特征。结果表明:(1)单一气体生成量、耗氧量及耗氧速率均随着煤自燃性的增强而增大,且CO生成量和耗氧速率急剧上升的拐点温度与出现C_2H_4气体的温度相同。(2)CO、CO_2和C_2H_4产生率具有明显的阶段性,且前两种气体最大产生率所对应的温度相同;当不同自燃性煤的温度超过80℃时,两组指标CO/ΔO_2和CO/CO_2均迅速增大,表明其氧化反应加快。(3)在TG-DSC试验中,煤的氧化燃烧过程可分为5个阶段,对应于4种特征温度。其中过渡稳定阶段指煤的质量保持稳定,是失重到增重的过渡态,且不同自燃性煤每个阶段持续时间及阶段性特征温度存在显著差异。

This paper intends to study the combustion characteristics of coals with different spontaneous combustion tendency. The oxidation characteristics of three coals were investigated by a coal oxidation kinetics testing system. The results show that with the increase of spontaneous combustion tendency, the generation amount of single gas, oxygen consumption and oxygen consumption rate all increased. The temperature inflections for the sharp increase of CO and oxygen consumption were same as the temperature for the generation of C4H4. The CO, CO2 and C4H4 generation rate had featured stages, and CO and CO2 involved the same maximum production rate temperature. The two indexes CO/△O2, CO/CO2 will increase rapidly when coals temperature was over 80℃, indicating that the degree of oxidation reaction was enhanced. Meanwhile, the process of coal oxidation combustion could be divided into five phases, with the corresponding four characteristic temperatures. The transition stability phase indicated coal quality remained stable, and it is the transition state of evaporated alleviative to the weight incremental. In addition, there was a significant difference in the duration of each stage and the characteristic temperatures of coals with difference spontaneous combustion tendency.