Thermokinetic parameters of the primary coal tars destruction in the presence of catalysts and polymeric materials

Abstract

The hydrogen-donor abilities of polymers and the activity of catalysts in the process of thermal destruction of the organic mass of primary coal tar (PCT) are studied by non-isothermal kinetics methods. PCT, magnetic microspheres, nickel-deposited chrysotilechrysotile and Fe3O4 nanocatalysts were used as initial raw materials. Рolymers such as polyethylene (PE), polystyrene (PS) and polyethylene glycol (PEG) were selected as a hydrogen donor. The phases Mg3[OH]4{Si2O5} and NiO were determined by X-ray phase analysis (XRD) in the obtained catalyst (nickel-deposited chrysotile), and the presence of highly dispersed nickel oxide particles on the surface and inside the nanotubes was shown by the transmission electron microscope (TEM). Nickel oxide particles of 8–11 nm and 30–37 nm were evenly distributed on the surface and inside the chrysotile nanotubes. The kinetic parameters of the thermal destruction of a mixture of PCT, catalyst and polymer material were determined on the basis of thermogravimetric analysis using the integral method and the method for determining the thermokinetic parameters by the inflection point on the thermogravimetric curve (TG). The change in the activation energy, rate constant and pre-exponential factor with an increase in the degree of destruction of the organic mass of the PCT is established. It was shown that the nature of polymers and catalysts significantly affects the value of the rate constant and the activation energy. The calculated activation energies of the thermal destruction of a mixture of coal tar with PS and PE in the presence of a catalyst (nickel-deposited chrysotile) by the first method are 47.6 kJ/mol and 40.4 kJ/mol, and by the second method are 47.3 kJ/mol and 86.5 kJ/mol respectively.