城市污泥等温热风对流干燥过程的能耗分析

Analysis of Energy Consumption in Isothermal Hot Air Convective Drying Process of Sewage Sludge

采用热重分析仪对城市污泥进行了不同温度(80、100、120℃)下的等温热风对流干燥试验,绘制了污泥干燥动力学曲线和各干燥阶段能量消耗特性曲线,获得了不同干燥温度和初始湿含量下污泥的干燥能耗数据。结果表明,干燥过程的能量利用效率随污泥湿含量的降低而显著下降,提高热风干燥温度可降低污泥干燥过程的能耗。在120℃的热风干燥温度下,污泥全干化能耗为3 750 kJ/kg。另外,结合试验结果,讨论了城市污泥热风对流干燥过程中的各种节能方法和措施。

Isothermal hot air convective drying test of sewage sludge was conducted by using the thermogravimetry-differential scanning calorimetry at drying temperatures of 80, 100 and 120 ℃. The sludge drying kinetics curve and energy consumption characteristic curve for each drying stage were plot- ted. The energy consumption data for drying of sludge with different drying temperatures and different ini- tial moisture contents were obtained. The results showed that the energy utilization efficiency decreased greatly with the decrease of sewage sludge moisture content, and higher drying medium temperature could decrease the energy consumption in the drying process distinctly. The energy consumption for complete drying of sludge at 120℃was 3 750 kJ/kg. Also, some energy-saving methods and measures were dis- cussed based on the experimental results.