为研究温度对内蒙白音华褐煤热解产物的影响规律,采用程序升温法在管式炉反应器上对白音华褐煤在不同温度下(400~600℃)进行热解,利用傅里叶红外光谱仪和氮气等温吸附方法对褐煤半焦化学组分和物理结构的变化规律进行研究,采用GC-MS和气相色谱结合在线电子天平的方法分别对焦油成分和各煤气产量进行分析,从而探究了褐煤的热解特性。结果表明:中低温热解条件下,随着热解温度的升高,半焦产率降低,而煤气和焦油的产率逐渐增加;煤气产量中,CO2最多,但在450℃之后稳定在74.4 mL/g;焦油组成中,脂肪烃和含氧化合物占主要成分,其含氮化合物主要以吡啶环和喹啉环的形式存在,且结构稳定;热解可有效提高褐煤煤阶,增大芳碳率和环缩合度;随着热解温度升高,煤样的平均孔径先增大后减小,比表面积和比孔容积则正好相反,这是挥发分析出、官能团分解和焦油生成的共同结果。
To evaluate the effects of temperature on coal pyrolysis products, Baiyinhua lignite was pyrolyzed at different temperatures (400-600 ℃) in tube furnace via temperature programming method. The chemical and physical structures of the obtained char were investigated using the Fourier infrared spectrometer (FTIR) and nitrogen isothermal adsorption method. Meanwhile, the GC-MS and gas chromatography combined with online electronic balance were adopted to analyze the composition of pyrolysis tar and gas yields to explore the lignite pyrolysis characteristics. The results show that, in the pyrolysis, as the pyrolysis temperature raised, the char yield reduced gradually while the pyrolysis gas and tar yields increased. As for the gas, the CO2 yield was the highest and reached a stable level of 74.4 mL/g at temperatures higher than 450 ~C Besides, fatty hydrocarbon and oxygen- containing compounds occupied the main part of tar composition while nitrogen-containing compounds mainly exists in the form of pyridine and quinoline rings with stable structure. Pyrolysis can effectively improve the coal rank and increase the aromatic carbon rate and ring condensation degree. Furthermore, as a result of volatile evolution, functional group decompositions and tar formation, the average pore diameter first increased and then decreased with the rising pyrolysis temperature, while the specific surface area and pore volume exhibited the opposite trend.