电渗透脱水对污泥热干燥特性的影响

Influence of electroosmosis dehydration on thermal drying characteristics of sludge

以污水厂机械脱水后的污泥作为研究对象,提出了采用电渗透-热干燥结合进行深度脱水的方法。通过对原泥以及电渗透脱水至不同含水率(67%、71%和76%)的污泥在热干燥过程中含水率和干燥速率的测定,分析电渗透脱水对污泥热干燥特性的改善规律。结果表明,经电渗透脱水至含水率为67%和71%的污泥在热干燥过程中的传热传质速率及干燥速率有明显提高,且干燥温度越高,电渗透后污泥的干燥速率与原泥的干燥速率差距越大。相同电压梯度及相同温度下电渗透至67%后进行热干燥耗能最少。实际应用中应结合能耗分析选择合适的电渗透程度及干燥温度,以达到最优效果。

In this study,the sewage sludge after mechanical dehydration was deeply dehydrated by combining electroosmosis dehydration and thermal drying method. The moisture contents and drying rates of sewage sludge before and after eletroosmosis dehydrated were determined in thermal drying process at the initial moisture content of 67%,71% and 76%,respectively. Moreover,the thermal drying characteristic improvement regulation of sewage sludge after eletroosmosis dehydrated was also analyzed. The results showed that the heat and mass transfer rate and also drying rate of eletroosmosis dehydrated sewage sludge with the initial moisture content of67% and 71% significantly increased. The drying rates were quite different between the treated and untreated sewage sludge by eletroosmosis at the same initial moisture content and the difference significantly increased with the temperature increase. At the same voltage gradient and drying temperature,the later thermal energy consumption was the lowest when the sewage sludge was initially dehydrated by eletroosmosis to the moisture content of 67%. In practical application process,the appropriate electroosmosis process and drying temperature should be chosen by energy consumption analysis in order to achieve the optimal effect.