Kinetic analysis using thermogravimetric analysis for nonisothermal pyrolysis of vacuum residue

Abstract

Pyrolysis is a relatively simple upgrading process that can produce light oil from unconventional oil and heavy residue. For effective utilization of pyrolysis processes, it is important to understand its kinetic parameters. In this study, the nonisothermal pyrolysis of vacuum residue (VR) was analyzed using a thermogravimetric analyzer and the activation energy of the VR pyrolysis reaction was estimated by several theoretical methods. It was found that isoconversional methods were more suitable than nonisoconversional methods for analyzing complex pyrolysis reaction of VR. The Friedman method, a differential isoconversional method, is thought to be the most appropriate among the various methods tested because it can describe the complexity of the pyrolysis reaction of VR and there is no need for information of exact reaction model and mathematical assumptions for temperature integral, which can raise systematic errors in the kinetic analysis. Finally, the kinetic parameters of VR pyrolysis were determined based on the results of Friedman analysis and distributed activation energy model (DAEM), and VR pyrolysis behavior was well expressed with the kinetic parameters obtained from DAEM analysis.