Application of Coal Tar Products and Evaluation of the Stability of Residual Marine Fuels

Although the quality of coal tar does not meet the demands for blended marine fuel, the properties of its components after processing are improved, and they can be considered as inexpensive blending components. Three types of coal tar products including light coal tar I, light coal tar II, and hydrogenated coal tar have been obtained and used in production of residual marine fuels. To minimize costs, a linear optimization method has been used, and all properties of the resulting products have met the required criteria. In addition, a novel analytical method was used to characterize the fuel stability. The analysis of a hydrocarbon composition and a mechanism of interaction between the resin and asphaltene have shown the main coal tar components affecting fuel oil stability are polycyclic aromatic hydrocarbons (PAHs) and resin. A condensation of PAHs and resin into asphaltene and an increasing complexity of asphaltene structure causes deposition of oil products under heating. Hydrogenation is able to effectively reduce the PAH content and the volume of formation of massive asphaltenes thus preventing fuel flocculation and deposition during aging in fuel tanks.