亚烟煤低温氧化元素迁移规律及原位红外实验

Experimental research on elemental migration rule and in-situ FTIR during sub-bituminous coal low-temperature oxidation

基于动力学与热力学理论,研究了煤升温过程中C,H,O,N,S五种基本元素的迁移转化规律,同时根据红外实验分析了煤中主要官能团变化趋势。结果表明,煤样在物理吸附和化学吸附阶段,碳氧化合物变化占主导地位,在化学反应阶段,碳氢化合物和含氮化合物变化频率超过碳氧化物。低温氧化过程中,H元素的表观活化能最小,N元素表观活化能最大,而O,S元素的表观活化能为负值,C,H,N元素迁移过程为吸热反应,O,S元素转化过程是放热反应。煤中脂肪族C—H在煤温上升的过程含量逐渐降低。煤中COOH含量与总体的C=O含量变化趋势一致,当温度超过120℃以后,两者含量逐渐增加,此外对煤低温氧化过程涉及到的化学反应步骤也进行了研究推导。

Based on Kinetics and thermodynamics theory, the migration rules of five basic elements including C, H, O, N and S were studied, and the variation trend of main functional groups was also analyzed during the coal heating process. The results show that variation of carbon oxide compounds played a leading role in the physical and chemical adsorption phase, while the variation frequency of hydrocarbons and nitrogen compounds exceeded carbon oxide com- pounds. The apparent activation energy value of H element was the smallest and the energy value of O and S element were negative. The migration process of C, H and N was an endothermic process respectively and that of O and S was an exothermic process. Aliphatic C--H in the coal was gradually decreased when coal was heated. The contents of COOH and C =O had same variation trend, and it was obviously that the contents of both groups increased gradually over 120 ℃. Besides ,the chemical reaction steps involved in coal low-temperature oxidation were also studied.