Pyrolysis model of oil sand using thermogravimetric analysis

In this paper, the derivative thermogravimetry (DTG) curve displays an overlapping peak which consists of two subpeaks for the major oil-producing stage of Indonesian oil sand. This study was conducted to supplement the insufficiencies of the previous studies, which neglected or oversimplified the processing of the overlapping peak and did not determine the kinetic mechanism. First of all, we assume a two-component parallel reaction model to describe the mass-loss process of the major oil-producing stage (overall stage) to obtain the separated stages. Then, we present an asymmetric multi-peak fitting method, bi-Gauss, to separate the overlapping peak. Based on the results of the bi-Gauss method, the kinetic mechanism was obtained using the integral master plot method, followed by the determination of the activation energy by the integral iso-conversional non-linear (NL-INT) method. The results show that the bi-Gauss method can produce satisfactory fitting results. Moreover, the separated stages follow single mechanism; while the overall stage does not follow a single mechanism and the mechanisms of the front and back segments of the overall stage are in accordance with those of the separated stages, which prove the reliability of the two-component parallel reaction model.