Thermo-oxidative characterization and kinetics of tar sands

In this research, non-isothermal kinetics and thermal analysis of Gerçüş tar sand sample is studied by DSC (differential scanning calorimeter) and TG/DTG (thermogravimetry). Experiments were performed using three different mesh size (20–35, 35–50 and >50) of sample. Differential scanning calorimeter (DSC) curves revealed three reaction regions in the temperature range of 20–600 °C. On the other hand, thermogravimetry (TG/DTG) curves of tar sand samples at different particle sizes demonstrated three stages of weight loss. Two different kinetic models (Coats & Redfern and Arrhenius) were used to determine the kinetic parameters of the samples and it was observed that the average activation energy values were between 17.5 and 26.6 kJ/mol, for reaction region-II and 126.2–160.1 kJ/mol for reaction region-III, respectively. In order to see the contribution of each region to the overall reactivity of the tar sand sample, weighted mean apparent activation energy of the samples are also determined.

► Thermal analysis curves revealed three reaction stages; as water volatilization, volatilization of organic substances and cracking of heavy organics.
► Higher burn-out temperatures were observed as the particle size is increased, but no effect on peak temperatures.
► Differences were observed in the activation energies of the tar sand sample of different mesh size in different models.
► Weighted mean apparent activation energy is determined for contribution of each region to the overall reactivity of tar sand samples.