Effects of thermal dissolution in different solvents on structural characteristics and pyrolysis behaviors of lignite
Effects of thermal dissolution in different solvents on structural characteristics and pyrolysis behaviors of lignite
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不同溶剂热溶解对褐煤结构特征及热解行为的影响
DOI：
10.1016/j.fuel.2018.12.042
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发表时间：
2019-04-01
期刊：
影响因子：
7.4
通讯作者：
Gao, Jinsheng
中科院分区：
文献类型：
--
作者：
Li, Yanling;Huang, Sheng;Gao, Jinsheng
以锡林浩特褐煤（XL）为原料，分别在正己烷、甲苯和甲醇中进行热溶解，然后将热溶解残渣（RTD）与XL在550 ℃低温下进行热解，探讨TD对XL结构特征和热解行为的影响。结果表明，经热处理后，XL的芳香碳含量（fa）增加，脂肪碳含量（f（al））和氧键碳含量（f（O））降低，表明XL的分子结构变得更加有序，尤其是在正己烷中。在三种RTD中，在290 ° C下获得的甲醇中的RTD（RTDM，290）表现出最大的芳族簇尺寸。290 ℃时的TD对XL的热解行为有显著影响。与XL相比，在290 ℃下获得的RTD（290）s）的热解呈现更高的焦炭产率，更低的焦油、气体和水产率。RTD在正己烷中在290 ° C（RTDH，290）下获得的热解表现出极低的焦油产率，这表明在TD期间从XL分离的低分子量化合物（LMWCs）可以运输到焦油中和/或作为氢供体以在热解过程中稳定自由基片段。虽然在290 ℃时甲醇可溶部分（SP）的产率高达9.45%，但RTDM，290的焦油产率几乎与XL相当，表明XL在甲醇中的溶胀作用显著，有利于焦油的产生。
Thermal dissolution (TD) of Xilinhaote lignite (XL) in n-hexane, toluene and methanol were carried out, and then the residues of thermal dissolution (RTDs) and XL were pyrolyzed at a low temperature of 550 degrees C to explore the effect of TD on structural characteristics and pyrolysis behaviors of XL. Results show that RTDs present higher aromatic carbon content (fa), lower aliphatic carbon (f(al)) and oxygen-linked carbon content (f(O)), indicating that the molecular structure of XL becomes more ordered after TD, especially that in n-hexane. Among three RTDs, the RTD in methanol obtained at 290 degrees C (RTDM,290) exhibits the largest aromatic cluster size. The influences of TD at 290 degrees C on the pyrolysis behaviors of XL are remarkable. Compared with XL, the pyrolysis of RTDs obtained at 290 degrees C (RTD(290)s) present higher char yields, lower tar, gas and water yields. The pyrolysis of RTD in n-hexane obtained at 290 degrees C (RTDH,290) exhibits extremely low tar yield, suggesting that the low molecular weight compounds (LMWCs) isolated from XL during TD can transport into tar and/or act as hydrogen donors to stabilize the radical fragments during pyrolysis processes. Although the methanol soluble portion (SP) yield is up to 9.45% at 290 degrees C, the tar yield of RTDM,290 is almost equal to that of XL, indicating that the swelling effect of XL in methanol is significant and it is conducive to the production of tar.