A study by density measurement of changes in pore structures of coals with heat treatment: Part 2. Micropore structure

✍ Scribed by Yūzō Toda

• Publisher: Elsevier Science
• Year: 1973
• Tongue: English
• Weight: 621 KB
• Volume: 52
• Category: Article
• ISSN: 0016-2361
• DOI: 10.1016/0016-2361(73)90029-x

✦ Synopsis

Changes in micropore structures of six Japanese coals during heat treatment up to 12OO'C were followed by measuring densities in n-hexane, in methanol and in helium. The micropore volumes were deduced from the difference between the reciprocals of the densities in n-hexane and in methanol.

The concept of the 'crystallite' was used in discussing the micropore structures of carbonized coals. Changes in the micropore structures were explained in terms of evolution of gases, change in the orientation of graphite-like layers, shrinkage of the structure, and so on. The different variations in micropore structures with heat treatment, between lower-rank coals and higher-rank coals, could well be accounted for by classifying the lower-rank coals and the higherrank coals as non-graphitizing carbon and,graphitizing carbon respectively. It is suggested that for coals and their carbonized products the entrance diameters of the micropores located between the crystallites are smaller than the diameter of n-hexane molecules.