NEW STRUCTURAL CONCEPT FOR CARBONIZED COALS

The aim of this study was to present a model of structure for solid pr oducts of bituminous coal carbonization carried out at end temperature s (ETCs) in the 600-750 degrees range. The products are of interest si nce they are used as raw materials for production of activated carbons . Moreover, a layer of such products occurring in coke ovens seems to play a crucial role in generation of excessive coking pressure in indu strial coking. The experimental data used in modeling were derived fro m the following: carbonization studies of coals and individual aromati c hydrocarbons, X-ray diffraction, transmission electron microscopy, p yrolysis-field ionization mass spectrometry, and electrical resistivit y measurements, The final step of model preparation relied on applicat ion of computational chemistry for search of stable conformers and for calculations of molecular orbitals, According to the model, semicokes contain two structural components: (i) oligomers that form nonplanar 3D networks of aromatic clusters (an extended system of conjugated pi- orbitals unites clusters of the network despite the fact they are not coplanar) and (ii) planar aggregates that arise from products of dehyd rocyclization reaction (the aggregates fill space between oligomeric n etworks). The two structural components represent optically isotropic and anisotropic phases, respectively.