Coal Dissolution by Heat Treatment at Temperatures up to 300 C in N-Methyl-2-pyrrolidinone with Addition of Lithium Halide. 1.
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- 作者：Chunqi Li ; Toshimasa Takanohashi ; Ikuo Saito ; and Masashi Iino
- 刊名：Energy & Fuels
- 出版年：2003
- 出版时间：May 2003
- 年：2003
- 卷：17
- 期：3
- 页码：762 - 767
- 全文大小：159K
- 年卷期：v.17,no.3(May 2003)
- ISSN：1520-5029
文摘
Coals of different ranks were heat-treated at temperatures up to 300 
C in the aprotic dipolarsolvent N-methyl-2-pyrrolidinone (NMP) with addition of lithium halides (LiCl, LiBr, and LiI).The treated products were extracted using a carbon disulfide/NMP (CS2/NMP) mixed solvent(1/1 by vol), and the dissolution yields were determined from the weight of the insoluble material.Addition of small amounts of lithium halides to CS2/NMP mixed solvent was reported to enhancethe room-temperature extraction yields for some high-rank coals, while little effect was observedfor low-rank coals (Energy Fuels 2001, 15, 141). On the other hand, in the present study, heattreatment in the presence of LiCl showed a greater effect on dissolution for low-rank than forhigh-rank coals. For low-rank Banko 97 coal (%C:70.0%), the dissolution yield was increased by41.4% at 300 C, from 50.4% in NMP alone to 91.8% with the addition of 2.4 mmol/g-coal LiCl,and the increased dissolution yield was attributed mainly to an increase in the amount of theheavy fraction; CS2/NMP-soluble and THF-insoluble (TIMS). Furthermore, the temperature ofheat treatment (175-300 C) and the quantity of LiCl added (0.6-3.6 mmol/g-coal) markedlyaffected the dissolution yield. When different lithium halides were used, the dissolution yieldwas increased in the order Cl- > Br- > I-; higher charge density of the anion of the additive wasassociated with higher dissolution yield. The mechanism of the observed effect of addition ofLiCl on coal dissolution is discussed.
C in the aprotic dipolarsolvent N-methyl-2-pyrrolidinone (NMP) with addition of lithium halides (LiCl, LiBr, and LiI).The treated products were extracted using a carbon disulfide/NMP (CS2/NMP) mixed solvent(1/1 by vol), and the dissolution yields were determined from the weight of the insoluble material.Addition of small amounts of lithium halides to CS2/NMP mixed solvent was reported to enhancethe room-temperature extraction yields for some high-rank coals, while little effect was observedfor low-rank coals (Energy Fuels 2001, 15, 141). On the other hand, in the present study, heattreatment in the presence of LiCl showed a greater effect on dissolution for low-rank than forhigh-rank coals. For low-rank Banko 97 coal (%C:70.0%), the dissolution yield was increased by41.4% at 300 C, from 50.4% in NMP alone to 91.8% with the addition of 2.4 mmol/g-coal LiCl,and the increased dissolution yield was attributed mainly to an increase in the amount of theheavy fraction; CS2/NMP-soluble and THF-insoluble (TIMS). Furthermore, the temperature ofheat treatment (175-300 C) and the quantity of LiCl added (0.6-3.6 mmol/g-coal) markedlyaffected the dissolution yield. When different lithium halides were used, the dissolution yieldwas increased in the order Cl- > Br- > I-; higher charge density of the anion of the additive wasassociated with higher dissolution yield. The mechanism of the observed effect of addition ofLiCl on coal dissolution is discussed.