操作条件对吸附分离辅助电渗透脱水特性的影响

Influence of Operation Conditions on Electroosmotic Dewatering Performance Assisted by Absorptive Separation

[目的]考察不同操作条件对吸附分离辅助电渗透脱水特性的影响。[方法]以经重力浓缩、絮凝和离心脱水后的污泥为试材,研究初始电压梯度对电渗透脱水效果、对电渗透脱水能耗的影响以及对电渗透脱水最大电流密度的影响,探讨电渗透脱水时间的优化方法。[结果]在12～24 V/cm电压梯度作用下,脱水10 min时,污泥含水率由79.9%脱水至64.7%～52.5%,同时污泥电渗透脱水能耗随脱水时间呈指数型增长。通过优化得到,在污泥电渗透脱水电压梯度为16 V/cm,脱水8 min时,污泥含水率从79.9%降到61.8%,脱水能耗为0.076 kWh/kg.H2O。[结论]增加电压梯度有利于污泥电渗透脱水,但电压梯度越高脱水能耗及极板所承受的电流密度越大。综合考虑,电压梯度应选择16 V/cm,污泥电渗透脱水时间以8 min为最佳。

[Objective] The study aimed to investigate the effects of different operation conditions on the electroosmotic dewatering performance assisted by absorptive separation.[Method] With the sludge after the gravity concentration,flocculation and centrifugal dehydration as the tested materials,the effects of the initial voltage gradient on the electroosmotic dewatering,electroosmotic energy consumption and the maximum current density after electroosmotic dewatering were studied and the optimization method for the electroosmotic dewatering time were discussed.[Result]Under the electrical potential gradient of 12-24 V/cm and the dewatering time of 10 min,the water content in the sludge was decreases from 79.9% to 64.7%-52.5% and the electroosmotic energy consumption of the sludge was increased exponentially with the time.The optimized the operation conditions were that when the electrical potential gradient for the electroosmotic dewatering of the sludge was 16 V/cm and the dewatering was 10 min,the water content in the sludge was reduced from 79.9% to 61.8% and the dewatering energy consumption was 0.076 kWh/kg-H2O.[Conclusion] Increasing the electrical potential gradient benefited the electroosmotic dewatering of sludge,but when the electrical potential gradient was higher,the dewatering energy consumption and the current intensity suffered by the electrode were greater.Through the comprehensive consideration,it was suggested that the electrical potential gradient should be selected as 16 V/cm and the electroosmotic dewatering time of the sludge of 8 min was optimum.