Increase in Extraction Yields of Coals by Water Treatment: Beulah-Zap Lignite

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• 作者：Masashi Iino ; Toshimasa Takanohashi ; Takahiro Shishido ; Ikuo Saito ; Haruo Kumagai
• 刊名：Energy & Fuels
• 出版年：2007
• 出版时间：January 2007
• 年：2007
• 卷：21
• 期：1
• 页码：205 - 208
• 全文大小：210K
• 年卷期：v.21,no.1(January 2007)
• ISSN：1520-5029

文摘

In a previous paper, we have reported that water pretreatments of Argonne premium coals, Pocahontas No.3 (PO), Upper Freeport (UF), and Illinois No. 6 (IL) at 600 K increased greatly the room-temperature extractionyields with a 1:1 carbon disulfide/N-methyl-2-pyrrolidinone (CS₂/NMP) mixed solvent. In this paper, the watertreatment of Beulah-Zap (BZ) lignite has been carried out and the results obtained were compared with thosefor the three bituminous coals above. The extraction yields of BZ with CS₂/NMP increased from 5.5% for theraw coal to 21.7% by the water treatment at 600 K. Similar to the other three coals, the water treatments at500 K gave little increase in the yields. The larger decrease in oxygen content and hydrogen-bonded OH andthe increase in the methanol swelling ratio by the water treatment suggest that the yield enhancements for BZare attributed to the removal of oxygen functional groups and the breaking of hydrogen bonds to a greaterextent than that for IL. From the characterizations of the treated coals and the extraction temperature dependencyof their extraction yields, it is suggested that, for high-coal-rank coals, PO and UF, the breaking of noncovalentbonds such as - interactions between aromatic layers and hydrogen bonds is responsible for the extractionyield enhancements.