Study on the preheating stage of low rank coals liquefaction: Product distribution, chemical structural change of coal and hydrogen transfer
Study on the preheating stage of low rank coals liquefaction: Product distribution, chemical structural change of coal and hydrogen transfer
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DOI：
10.1016/j.fuproc.2017.01.028
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发表时间：
2017-05-01
影响因子：
7.5
通讯作者：
Li, Wen
中科院分区：
文献类型：
--
作者：
Hao, Pan;Bai, Zong-Qing;Li, Wen
在氮气保护下，研究了云南褐煤和哈密次烟煤在200-350 ℃四氢萘中直接液化的预热阶段。为了揭示煤与溶剂在预热过程中的产物特性和氢转移过程，采用热重-质谱联用（TG-MS）、X射线光电子能谱（XPS）和气相色谱-质谱联用（GC-MS）等分析手段对煤与溶剂在预热过程中的氢转移过程进行了研究。结果表明，轻产物，即，油、气和水在预热过程中随着温度的升高而增加。YN和HM在350摄氏度下分别实现51.69%和44.19%（daf）的轻质产品产率。此外，原煤中的含氧官能团，如羧基，醚和醇在预热后被还原。此外，即使在200 ℃下，氢转移也达到可察觉的程度，并且转移的氢的量随着温度的升高而增加。在预热阶段，氢转移与转化率呈正相关。比较两种煤样，YN在此温度范围内由于其较高的热反应性而获得较高的转化率和氢转移。然而，在350 ℃下，HM获得比YN更高的油产率，因为原煤的高氢转移量和H/C比促进油产率。(C)2017爱思唯尔B. V.保留所有权利。
Preheating stage of direct liquefaction of Yunnan lignite (YN) and Hami sub-bituminous coal (HM) in tetralin at temperature range of 200-350 degrees C was investigated under nitrogen atmosphere. In order to reveal the product characteristics and hydrogen transfer between coal and solvent during preheating process, thermo-gravimetric analyzer coupled with mass spectrometer (TG-MS), X-ray photoelectron spectroscopy (XPS) and gas chromatography coupled with mass spectrometer (GC-MS) were employed. The results show that yields of light products, i.e., oil, gas, and water, increase with raising temperature during the preheating process. YN and HM achieve 51.69% and 44.19% (daf) light products yields at 350 degrees C, respectively. Moreover, oxygen-containing functional groups, such as carboxyl, ethers, and alcohols in raw coal are reduced after preheating. In addition, hydrogen transfer achieves a perceptible extent even at 200 degrees C and the amount of transferred hydrogen increases with raising temperature. A positive dependence of hydrogen transfer on conversion is observed during preheating stage. Comparing the two coal samples, YN obtains higher conversion and hydrogen transfer due to its higher thermal reactivity at this temperature range. However, HM achieves higher oil yield than YN does at 350 degrees C since high hydrogen transfer amount and H/C ratio of raw coal promote the oil yield. (C) 2017 Elsevier B.V. All rights reserved.