CO_2气氛下乌拉盖煤热解过程中气体释放特征及机理

Release characteristics and mechanism of gas products in Wulagai lignite pyrolysis over CO_2

在热重分析仪上以CO2为气化介质，制取了不同温度下乌拉盖煤半焦，并采用SEM和FTIR分析半焦的物化特性变化规律。利用TG-FTIR研究其气相产物的析出规律和机理。研究发现，煤焦表面孔隙随着挥发分的析出逐渐变得发达直至变形塌陷。褐煤中的有机官能团主要在320～850℃断裂缩合，850℃时褐煤已基本气化完全。烷烃类气体主要在热解阶段析出，由甲基、亚甲基、甲氧基中C-H键的断裂、重组所致；热解段CO的析出归因于羧基等含氧官能团的断裂，气化段是由于CO2气氛参与了焦炭的气化反应。

Coal char samples,partly burnt with CO2 under different temperatures,were prepared using a Thermogravimetric Analysis（TG）. The physic-chemical property was analyzed with Scanning Electron Microscope（SEM） and Fourier Transform Infrared Analysis（FTIR）. The release regularity and the forming characteristic of the gas were investigated in the TG coupled with a FTIR spectrometer. It was observed that the pore structure of char increased with the precipitation of volatile until the collapse deformation. The cracking and reforming of functional group of char mainly take place at 320-850 ℃. The lignite has been completely gasified at 850 ℃. Alkane gas is mainly released out in the stage of pyrolysis. It was mainly generated by the cracking and reforming of C-H functional groups of methyl,methylene,methoxy. CO was mainly generated by the cracking and reforming of C-O-（C） of oxygen functional groups,such as carboxylic,and CO2 participated in the gasification of char.