Modification and Investigation of the Catalytic Activity of Coal Additives for Veba Combi Cracking (VCC)

Coal additives impregnated with nickel and iron for use in Veba Combi Cracking technology are investigated. The morphology of the surface and pore space of a modified coal additive is presented. The additive is shown to be similar to lignite in terms of its elemental composition. A comparative assessment of the textural properties of the original and modified coal additive is carried out. A relationship between the composition of the coal additive and the final products of heavy residue cracking in the presence of hydrogen in the temperature range of 435–460°C and a pressure of 17 MPa is shown. Catalytically active metals present in the composition of the coal additive were shown to affect the conversion degree of resinous-asphaltene components, formation of coke-like substances, and yield of light distillate fractions. The catalytic activity of the nickel- and iron-impregnated coal additive in the process of tar thermal cracking in a hydrogen atmosphere is established. The results obtained confirm the positive effect of impregnation of coal additives with catalytically active centers. This effect consists in an increased conversion degree of high-molecular components of heavy residual oil feedstock, thus indicating the significant potential of Veba Combi Cracking technology.