Effect of Nickel Nanopowder on the Thermal Degradation of Coal Tar Distillate

Regularities of influence of nickel nanpowder on the thermal degradation of coal tar distillate were determined using model-free Kissinger, Flynn-Wall-Ozawa and model-fitting Coats-Redfern methods. Coal tar distillate with a boiling point <350 °C was obtained by simple distillation of primary coal tar from the Shubarkol deposit. Nickel nanopowder was used as a catalyst and was added to coal tar distillate in a quantity of 1 % of the mass of the distillate and then the process of thermal degradation of coal tar distillate was conducted at heating rates 5, 10 and 20 °C/min in an inert gas medium. Nickel powder was obtained by high-voltage discharge impact on the dc electrolysis. X-ray diffraction (XRD) analysis showed that the obtained nickel powder has face-centered cubic structure and the average crystallite size calculated by Scherrer equation was ~ 34 nm. Calculations of activation energy were performed via processing of thermogravimetric data. The Kissinger method showed that the activation energy value decreases from 145.19 kJ/mol to 43.65 kJ/mol, by the Flynn-Wall-Ozawa (FWO) method the value decreases from 152.82 kJ/mol to 51.65 kJ/mol, and by the Coats-Redfern method the value decreases from 143.38 kJ/mol to 52.64 kJ/mol. Applicability of these methods are ensured by the high values of correlation coefficients.