The Nature of the Aggregated Structure of Upper Freeport Coal

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• 作者：Toshimasa Takanohashi ; Hiroyuki Kawashima ; Takahiro Yoshida ; and Masashi Iino
• 刊名：Energy & Fuels
• 出版年：2002
• 出版时间：January 2002
• 年：2002
• 卷：16
• 期：1
• 页码：6 - 11
• 全文大小：241K
• 年卷期：v.16,no.1(January 2002)
• ISSN：1520-5029

文摘

Data for the sorption and interaction of alcohols with the coal suggested Upper Freeport coalhas a large number of micropores into which relatively bulky reagents could diffuse onlymarginally; micropores may be molecular voids in the aggregated. The irreversible structuralrelaxation observed on differential scanning calorimeter (DSC) thermograms at 350 C is probablyvery similar in nature to that caused by extraction with highly efficient mixed solvents such ascarbon disulfide/N-methyl pyrrolidinone (CS₂/NMP). Upper Freeport coal must be greatly relaxed(swollen) before solvents have access. A molecular dynamics simulation of relaxation at severaltemperatures was carried out on a model structure for the aggregated coal. A large change inthe volume of the model structure was found between 350 C and 400 C, the region in which theirreversible peak was observed in the DSC thermograms. Moreover, in agreement with theexperimental results, the structural changes caused by "heating" in the simulation were notreversible. These results suggested that irreversible structural relaxation caused by heating isthe result of thermal stabilization of the strained structure of the raw coal.