The drying of oily sludge is an essential preliminary step for further effective thermal utilization. In this
paper the effects of different diameters (4e8 mm) and temperatures (105e250 C) on the drying
characteristics of long cylindrical oily sludge made by the sludge shaper were studied. The drying
characteristics were studied in an electro-thermal constant-temperature dry box. Results indicate that an
increase in temperature and a decrease in diameter accelerate the drying rate and shorten the drying
time. After drying, fractures appeared in the solid skeleton of long cylindrical oily sludge, resulting in the
production of smaller cylindrically-shaped particles. Besides the experimental analysis, a mathematical
drying model was selected for such a long cylindrical oily sludge. Based on the obtained experimental
data, a Boltzmann drying model was written in the following form: MR (moisture ratio) ¼ A1/(1 þ e(t k)/
n). The mathematical model can be used to predict accurately the drying process of the long cylindrical
sludge in the temperature range of the experiment. The model can furthermore be used to develop more
efficient sludge drying equipment.