Experimental and modeling study of the long cylindrical oily sludge drying process

The drying of oily sludge is an essential preliminary step for further effective thermal utilization. In this paper the effects of different diameters (4-8 mm) and temperatures (105-250 °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) = A₁/(1 + 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.