Study on Thermal Kinetic Mechanism of Oil Shale

Abstract

Thermogravimetric experiments were performed on Pyris-1 TGA thermal analyzer, and pyrolysis curves of four oil shale samples at different heating rates were obtained. According to Malek's method, the kinetic mechanism function of sample was determined by using the standard curves and experimental curves of y(Â?)-Â?. The influences of heating rates and species of oil shale samples on the kinetic mechanism function were analyzed. The results showed that, at the different heating rates, the heat transfer rates, temperature gradient and the chemical reactions in the interior of oil shale samples are varied, and then the kinetic mechanism function of sample is changed; The kinetic mechanism functions are not unique at the special heating rate for a single sample, which depend on the conversion rate Â?: When a Â? is less than 0.5, the weight loss during pyrolysis process, has been attributed to the loss of moisture, interlayer water from clay minerals and thermal decomposition of minerals; When Â? equals to 0.5 or so, the weight loss is due to cracking of clay minerals; When Â? is greater than 0.5, the decomposition of carbonate minerals (such as calcite, dolomite, ankerite and other carbonates). When the species of samples are different, chemical structure and the physical characteristics (such as heat transfer coefficient, voidage, specific heat capacity) are various, kinetic mechanism functions are also different, the serial numbers of kinetic mechanism functions are advanced with Â? increasing for a special sample.