Heat transfer characteristic of oil shale particle during the retorting

The heat transfer occurring within oil shale particle is a dominant fundamental cause affecting shale oil yield and energy consumption of industrial oil shale retorts. For exploring this property, the shape of crushed Gonglangtou oil shale particle is first investigated, showing very obvious platy structure especially in the equivalent diameter range of 4–25 mm. So, it is more appropriate to describe oil shale particle with thin rectangle model. And then, a mathematical heat transfer model is developed to analyze the thermal behavior within oil shale particle in the process of the retorting, incorporating the pyrolytic heat as an internal heat sink. Previous experimental data are applied to validate this model. Furthermore, the central temperature history and heating time of oil shale particles with different sizes are predicted at various heating rates using this heat transfer model, showing that platy structure characteristic offers an important role for the heat transfer process and even for the particle fragmentation. In order to improve retorting efficiency and reduce energy loss, it is recommended at last that the residence time of oil shale in the retorting reactors should fully consider the heating time of oil shale particle.