Abstract Ultrasonic-assisted extraction (UAE) and direct liquefaction of the corresponding residue were conducted on an acid-washed ashless Hefeng bituminous coal (HBCAW). Petroleum ether (PE), carbon disulfide (CDS), methanol (MeOH), acetone and isometric CDS/acetone mixture (IMCDSAM) were used to sequentially extract HBCAW via UAE to obtain extracts (E1–E5). Gas chromatograph/mass spectrometer (GC–MS) analysis showed that most of the free molecules were extracted in the first two stages, and E1 and E2 were mainly consisted of aliphatics and alkanes. PE presented a strong extraction ability for the low polar compounds, and the average molecular weight of E2 was higher than E1. While E3 is more varied containing more complex molecules than E1 and E2. IMCDSAM was more favorable for the diffusion and dissolution of alcohols. Direct liquefaction performance suggested that the oil yields of Hefeng bituminous coal (HBC), HBCAW and the fifth stage extraction raffinate (ER5) were 66.00%, 63.57% and 44.11%, respectively, and that the conversion of ER5 was only 69.67%, much lower than HBC and HBCAW (82.75% and 82.68%). Higher yield of gaseous product for ER5 might be resulted from the looser coal structure by UAE process, resulting in more small molecules during the direct coal liquefaction.

中文翻译：

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鹤峰煤五段序提取及提取渣直接液化性能

摘要 对酸洗无灰鹤峰烟煤（HBCAW）进行了超声辅助萃取（UAE）和相应残渣的直接液化。石油醚 (PE)、二硫化碳 (CDS)、甲醇 (MeOH)、丙酮和等量 CDS/丙酮混合物 (IMCDSAM) 用于通过阿联酋依次提取 HBCAW 以获得提取物 (E1-E5)。气相色谱/质谱 (GC-MS) 分析表明，大部分游离分子在前两个阶段被提取，E1 和 E2 主要由脂肪族和烷烃组成。PE对低极性化合物表现出很强的萃取能力，E2的平均分子量高于E1。而 E3 比 E1 和 E2 更多样化，包含更复杂的分子。IMCDSAM 更有利于醇的扩散和溶解。直接液化性能表明，和丰烟煤（HBC）、HBCAW和五级抽提残液（ER5）的产油率分别为66.00%、63.57%和44.11%，而ER5的转化率仅为69.67%，远远高于低于 HBC 和 HBCAW（82.75% 和 82.68%）。ER5 较高的气态产物产率可能是由于UAE 工艺使煤结构更松散，从而在煤直接液化过程中产生更多的小分子。