Carbonization of Heavy Oils (Part 6)

The low temperature carbonization of low-molecular compounds, pitches, reduced crudes, synthetic crude and bitumen has been studied by polarized-light microscopy. Transformation to mesophase from the starting materials given varied depending on thermal decomposition, polymerization-behaviours of the components in them. At the early stage of carbonization, thermally reactive components transform to the mesophase, textures of which are of fine mosaic. Thermally stable components give coarse or fibrous textures at the final stage of mesophase transformation.Rearrangements of polyaromatics, which consists of mesophase lamella, are interrupted by the addition of dehydrogenating reagent through carbonization process, presumably by increasing the degree of crosslinking in the decomposing carbonaceous materials. On the other hand, mesophase transformation alters to coarse or fibrous textures during the carbonization under pressure or in the presence of AlCl3. This is the reason why the viscosity of mesophase formed in the carbonization mentioned above is low enough to permit appreciable structural rearrangement by flow during and after coalescence.