Kinetics of the thermal decomposition of oil shale from Puertollano (Spain)

The kinetics of the thermal decomposition of Spanish oil shale was studied using isothermal and non-isothermal thermogravimetric analyses (TGA). The isothermal TG data were studied at different particle sizes (0.250×10−3, 0.505×10−3 and 0.925×10−3 m) and three temperature plateaux (703, 688 and 673 K). For the kinetic analysis, the Integral Method was used. n-isothermal weight-loss data was analysed at different heating rates (5, 10, 15, 20 and 50 K/min) up to 1173 K and for a particle size of 0.250×10−3 m. Three methods were applied for the determination of the kinetic parameters: the Direct Arrhenius Plot Method, the Integral Method and the Differential Method. n engineering point of view, the rate of the thermal decomposition of Spanish oil shale can be suitably described by overall first-order kinetics. We also found that transport effect problems affected the observed rate when the heating rates were higher than 10 K/min; additionally, no mass and heat transfer resistance was observed for the different particle sizes studied. sults obtained from the isothermal method give an apparent activation energy of 150 kJ/mol and a frequency factor of 2.11×108 s−1, while for the non-isothermal method these results were: E=167 kJ/mol and A=2.16×109 s−1. The pyrolysis rates of Spanish shale are compared with those of Anvil Points, Clear Creek and Moroccan shale.