Comparison of Different Kinetic Models for Heavy Oil Oxidation Characteristic Evaluation

Despite many studies of heavy oil oxidation characteristics, kinetic mechanisms with the comparison of different kinetics models are not well understood, because of the complexities of oil components and nonisothermal oxidation processes. Moreover, it is urgent to further evaluate the feasibility and accuracy variations of different kinetic models to optimize the kinetic model for specific situations and purposes. Therefore, thermogravimetry (TG-DTG)/differential scanning calorimeter (DSC-DDSC) thermograms under different heating rates were comprehensively studied in this work to elucidate the nonisothermal oxidation behavior with the heating rate influence. Then, based on the comparison analysis of model-fitting and model-free methods, the comparisons of kinetic parameters, reaction order, and activation energy distribution were evaluated. In addition, the results indicated the nonisothermal oxidation kinetics parameters varied with the reaction orders and kinetic models. Besides, an obvious increase of low-temperature oxidation (LTO) activation energy resulted from the negative temperature coefficient (NTC) effect. Moreover, the preferable kinetic model is ascribed to the specific analysis purposes, as well as the acceptable accuracy of the calculated result and the model practicability.