Changes in coal composition during air oxidation at 200–250 °C

✍ Scribed by W.S. Kalema; G.R. Gavalas

• Publisher: Elsevier Science
• Year: 1987
• Tongue: English
• Weight: 782 KB
• Volume: 66
• Category: Article
• ISSN: 0016-2361
• DOI: 10.1016/0016-2361(87)90234-1

✦ Synopsis

Air oxidation of two bituminous coals and a lignite was carried out in a fluidized bed reactor at 2Ot-250°C. The gaseous products were analysed by gas chromatography and solid samples were titrated to determine carboxylic and total acidity and were subjected to 13C n m.r. spectrometry to determine the fraction of aromatic carbon. Elemental composition, heating value and ash content were also determined. During the first few hours oxidation-induced devolatilization proceeded simultaneously with oxidation. Oxidation of the high volatile bituminous coal for 12 hat 200°C raised the carboxylic groups from 0.37 to 2.1 meq g-' and the total acidity from 1.5 to 5.3 meq g-l. The acidic groups seem to be largely distinct from oxygenated groups that are precursors to CO and CO, products. Oxidation of the same coal at 200°C consumed aromatic as well as aliphatic carbon at relative amounts 1:3 to 1:4.