Pressure and temperature effects on the hydrogenation of coal-derived asphaltene

✍ Scribed by Isao Yoshimoto; Hironori Itoh; Masataka Makabe; Koji Ouchi

• Publisher: Elsevier Science
• Year: 1984
• Tongue: English
• Weight: 671 KB
• Volume: 63
• Category: Article
• ISSN: 0016-2361
• DOI: 10.1016/0016-2361(84)90322-3

✦ Synopsis

Pressure and temperature effects on hydrogenation reactions were examined using coal-derived asphaltene at 390,420 and 45o"C, under 3 and 10 MPa of hydrogen partial pressure. Higher conversion was obtained at higher reaction temperatures. Benzene-insoluble material (BI) was formed at higher temperatures especially at low hydrogen pressure, this BI being one-third of the reaction product at 450°C. From structural analysis of unreacted asphaltenes and product oils, at 390°C. it was concluded that smaller molecular components convert to oil initially and the larger molecules remain as unreacted asphaltene. Under higher hydrogen pressure for all temperatures carbon aromaticity (f,) and number of aromatic ring per structural unit (I?,,,) in unreacted asphaltenes were lower than those under lower hydrogen pressure suggesting that hydrogenation of the aromatic nucleus was promoted by higher pressure. At lower hydrogen pressure, R,,, for asphaltenes at higher temperature is larger than that at lower temperature. This suggests that at lower hydrogen pressure, dehydrogenation or condensation reactions occur more easily. A large effect at higher hydrogen pressure was a reduction in the extent of condensation reactions. Higher reaction temperatures contribute to splitting of bridged linkages SO reducing molecular size and degree of aromatization.