Molecular mobility of high-volatile bituminous coals accompanying drying

✍ Scribed by Masaharu Nishioka

• Book ID: 103092756
• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 657 KB
• Volume: 73
• Category: Article
• ISSN: 0016-2361
• DOI: 10.1016/0016-2361(94)90188-0

✦ Synopsis

Pyridine-extractability, solvent swelling and free swelling index of selected high-volatile bituminous coals decreased upon drying under vacuum at 80-120°C overnight. The temperature necessary to induce these changes varied among the coals. This behaviour was attributed to molecular association caused by molecular mobility after and/or during the removal of volatile matter such as water. The following mechanism is proposed. Molecules in the raw coals are partly blocked by hydrogen bonds. Water and functional groups such as -COOH and -OH are partly incorporated into these hydrogen bonds. During the drying step, the blocked water and presumably CO, are eliminated, a glass transition temperature is locally lowered, and coal molecules can move and form a more stable and associated state.