Carbonization and liquid-crystal (mesophase) development. Part 2. Co-carbonization of aromatic and organic dye compounds, and influence of inerts

• Published in: Fuel (Guildford) 1973-10, Vol.52 (4), p.234-242
• Main Authors: Marsh, Harry, Foster, Jean M., Hermon, Gail, Iley, Margaret
• Format: Article
• Language: English
• ISSN: 0016-2361; 1873-7153
• DOI: 10.1016/0016-2361(73)90051-3

A detailed investigation is reported of the effects of co-carbonization of aromatic compounds, molecular weight 128 to 516, upon resultant anisotropic structures in cokes prepared therefrom. Additions of graphitic and quartz particles, and carbon blacks, were also studied. Carbonizations were carried out under hydraulic pressures (transmitted through an impervious foil) from 130 to 290 MN m −2 to a maximum heat-treatment temperature of 873 K, the mesophases being examined by optical and scanning electron microscopy. The smaller molecules, e.g. naphthalene and phenanthrene, form mesophase spheres 15 μm in diameter, but the larger organic dye molecules, e.g. dibenzanthrone, form small coalesced mosaics of only 0.2 to 3 μm. The shapes and sizes of the resultant anisotropic structures in semi-cokes from single compounds and mixtures are discussed in terms of rates of chemical pyrolytic processes, mobilities of molecules in the plastic phase, rates of growth of the mesophase, and viscosities of mesophase and plastic phase. A brief description of anisotropy in cokes from coals is summarized and causes are discussed of the small size of the anisotropic unit (1 μm), the non-coalescence (in general) of the anisotropic unit, and the occurrence of larger (10 μm) elongated anisotropic structures in cokes. The ability of the mesophase (liquid crystal) to orientate itself parallel to liquid-solid and liquid-gas interfaces, and the relevance of this property, is emphasized.