Heat transfer of oil shale in a small-scale fixed bed

Abstract

Heat transfer experiments on Longkou oil shale were carried out in a fixed-bed reactor. Temperatures at different positions in the reactor were determined. With increasing heating rate, the temperature difference between center and exterior of the reactor increased, the time needed to get to constant temperature decreased, while the time needed to reach final pyrolysis temperature decreased. A pseudo-homogeneous one-dimensional heat transfer model was developed, and analytical expressions were obtained on the basis of mathematical derivation. It was found that the coefficient of heat conductivity is a polynomial function of temperature. The Longkou oil shale could be seen as a poor heat conductor because of its low coefficient of heat conductivity. Usually, there are many factors to affect coefficient of heat conductivity, including the composition, density, moisture content, temperature, particle size and particle size distribution. Reasonable values of heat conductivity in different temperature ranges were determined using the developed model. The calculated results using heat transfer model for Longkou oil shale are reasonably agreed with actually measured temperature.