脱水污泥薄层干燥特性及动力学模型分析

采用薄层干燥方式进行脱水污泥热干燥的研究,考察了污泥的干燥特性,并引入薄层干燥模型进行数值分析.结果表明, Logarithmic模型比其他模型更适合薄层污泥干燥分析.应用Fick扩散模型,得到80~150℃条件下薄层污泥干燥的有效扩散系数的变化范围为8.486′10-10~4.386′10-9m2/s,并根据Arrhenius经验公式建立温度与扩散系数的关系,得到污泥干燥时水分扩散的活化能为29.56kJ/mol.

Thin layer drying characteristics and kinetics model of dewatered sludge

The drying of sludge presently became an important procedure for sewage disposal. The thin layer drying behavior of sewage sludge was investigated in an indirect drying process and the mathematical modeling was performed by using thin layer drying models. The logarithmic model was found to show better predictions. At the same time, moisture transfer from sewage sludge was described by applying the Fick’s diffusion model. The effective diffusivity coefficient of moisture transfer varied from 8.486′10-10m2/s to 4.386′10-9m2/s over the temperature 80℃ to 150℃. In addition, the temperature dependence of the effective diffusivity coefficient was expressed by Arrhenius type relationship. The activation energy for the moisture diffusion of sludge drying was found to be 29.56 kJ/mol.