Chemistry and Structure of Coal Derived Asphaltenes and Preasphaltenes. Quarterly Progress Report, July-September 1981

摘要

Coal liquids from Catalytic Incorporated and FMC-COED were separated into oil and resin (pentane soluble), asphaltene (pentane insoluble but benzene soluble) and preasphaltene (benzene insoluble) fractions using Soxhlet extraction. The fractions were analyzed using elemental analyses and the Brown-Ladner method. These fractions were pyrolyzed at atmospheric nitrogen pressure at standard conditions to 500 exp 0 C. The oxygen content and structural parameters of the precursors were compared for solvent fractions of the coal liquids to determine the effects on microstructure and yield is the pyrolysis residues. Pyrolysis yield was found to increase with increased aromaticity and oxygen content. The more aromatic molecules have fewer aliphatic chains to crack off and distill away as gas. The oxygen increases the yield by cross-linking the pyrolysis products and reducing the gas yield. The microstructure is determined primarily by the oxygen content of the precursor. When aromaticity is the same in two precursors, the mesophase growth is suppressed in the material with more oxygen.