煤低温氧化的微区组分分析与反应性研究

STUDY ON THE COMPONENT OF PULVERIZED COAL SURFACE AND ITS REACTIVITY DURING LOW-TEMPERATURE OXIDATION

煤的低温氧化对着火性能、反应性、煤焦质量以及煤的自燃有重要影响．本文通过TGA-DSC、FSEM和EBSP研究了烟煤和无烟煤的低温氧化特性,研究表明:活性较高的煤表面固相氧的浓度增量比热重低温段的表观增重量大得多;根据最大吸氧量确定的着火温度随煤变质程度的加深和升温速率的增加而增加;升温速率小于1／12 K／s时,最大氧化速率和最大吸氧量能代表煤的氧化活性;含灰量低的中等变质程度的煤氧化活性最高;化学吸氧经历了从临界活化能、到活化能减小再增加到极大最后吸附终止的过程．

For the coal oxidation at low temperature significantly influencing on ignition, reactivity, quality of coke and self-ignition, anthracite and soft coal oxidation were studied at low-temperature by making use of TGA-DSC AND FSEM-EBSP, it is shown that for the higher reactivity coal, the increment of solid phase oxygen concentration on char surface is much more than the apparent weight increment for char adsorbing oxygen in TGA; The ignition, corresponding temperature of the maximum quantity of adsorbing oxygen, increases with the increase of coal bank and heating rate; The reactivity is characterized by maximum rate of coal oxidation and the maximum quantity of adsorbing oxygen at heating rate less than 1/12 K/s; The most reactive coal is in the middling coal-bank; Coal adsorbing oxygen goes through initial activation energy, and decreasing to a very low level, then rising up to a very high level until ending up the course.