Experiment and kinetics model analysis on thin layer drying of paper mill sludge

 A series of experiments on the thin-layer drying of paper mill sludge were carried out to investigate the effects of temperature on the drying characteristics of paper mill sludge, and the thin-layer drying model was adopted to simulate the process of sludge drying. The result shows that the higher the temperature of drying and the thinner the layer of drying, the quicker the rate of drying. As the drying temperature rises from 80℃ to 160℃, the maximum drying rate increases from 0.008g/(g·min) to 0.030g/(g·min). Modified page is a model to best describe the drying process of the paper mill sludge in oven. In addition, moisture transfer from paper mill sludge can be described by Fick′s diffusion equation. It is obtained that the effective diffusion coefficient of dried samples of paper mill sludge ranges from 2.2×10^-10m²/s to 3.96×10^-10m²/s at temperatures from 80℃ to 160℃. By using Arrhenius equation, the activation energy of 9.435kJ/mol for the moisture diffusion is determined.