Effects of hydrothermal treatment on physico-chemcial structures and liquefaction behaviors of lignite
Effects of hydrothermal treatment on physico-chemcial structures and liquefaction behaviors of lignite
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DOI：
10.1016/j.fuel.2019.116636
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发表时间：
2020-03-01
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, Huan;Wu, Shiyong;Gao, Jinsheng
研究了水热处理对褐煤理化结构和液化行为的影响。将脱矿后的褐煤在N-2气氛下70 ~ 280℃进行水热预处理，测定了预处理后煤的理化结构。结果表明，130 ~ 190℃的水热处理可以抑制褐煤中H、O含量的还原以及羧基和酚羟基的分解。这也有利于褐煤中H含量的增加、中孔的形成和C-O的分解。经水热处理后的煤在430℃H-2气氛下液化。结果表明，在适宜温度（130 ~ 190℃）下，预处理煤的沥青前质和油的产率均高于脱矿煤。这表明水热处理在沥青质形成和沥青质转化为低分子化合物方面发挥了积极作用。液化油的组分分析表明，水热处理能促进多环芳烃向单环芳烃的转移，使液化油的分子量降低。在液化过程中，孔隙体积和比表面积的增大有利于氢的传递，从而提高了褐煤的液化活性。
The effects of hydrothermal treatment on physico-chemcial structures and liquefaction behaviors of lignite were studied in this paper. The lignite after demineralization was hydrothermally pretreated at 70-280 degrees C under N-2 atmosphere, and physico-chemcial structures of pretreated coal were determined. The results showed that hydrothermal treatment at 130-190 degrees C could inhibit the reduction of H and O contents and the decomposition of carboxyl groups and phenolic hydroxyl groups in lignite. It was also beneficial to the increase of H content, the formation of mesopores, and decomposition of C-O in lignite. After hydrothermal treatment, the pretreated coal was liquefied at 430 degrees C under H-2 atmosphere. The results showed that the yields of preasphaltene (PA) and oil of pretreated coal at appropriate temperatures (130-190 degrees C) were higher than those of demineralized coal. These indicated that the hydrothermal treatment played positive roles in the formation of PA, and conversion of asphaltene (AS) to low molecular compounds. The components of liquefaction oil showed that hydrothermal treatment could promote the transfer from polycyclic aromatic hydrocarbons to monocyclic aromatic hydrocarbons, thus leading to a decrease in molecular weight of liquefaction oil. During the liquefaction process, the increases of pore volume and surface area were beneficial to hydrogen transfer, thus improving the liquefaction activity of lignite.