Abstract

In this paper, the semi-theoretical kinetics equations were proposed and the electro-dewatering experiments of sludge were conducted to analyze the kinetics laws of electro-dewatering under constant voltage and constant current. The results showed that the decline rate of moisture content remained stable under constant current, while the decline rate of moisture content kept decaying in the operating mode of constant voltage. No matter in what kind of operating mode, the change in decline rate of moisture content was consistent with that of filtrate flow rate, both of which were essentially dependent on the current. The follow-up electro-dewatering tests under constant voltage were carried out by using three different kinds of sludge to understand the mechanism of electro-dewatering. The results showed that the main parameters that controlled the electro-dewatering behavior were measured current, conductivity and zeta potential of sludge. When treated at 30 V, sludge C reached the lowest moisture content, owing to its higher conductivity and zeta potential. However, the poorer electro-osmotic effect of sludge C led to its higher average unit energy consumption. By comparison, an increase of applied voltage was more effective for electro-dewatering process of sludge C but at the expense of higher energy consumption, while sludge A and B were more inclined to improve the electro-dewatering effect by extending the dewatering time. Finally, the derived equations were demonstrated by the experiments, which could provide guidance for the practical applications.

摘要

本文提出了半理论动力学方程，并进行了污泥电脱水实验，分析了恒压恒流条件下电脱水的动力学规律。结果表明，恒流下含水率下降率保持稳定，恒压工况下含水率下降率不断衰减。无论在何种工况下，水分含量下降速率的变化与滤液流量的变化一致，两者本质上都依赖于电流。以三种不同的污泥进行后续恒压电脱水试验，了解电脱水机理。结果表明，控制电脱水行为的主要参数是测量污泥的电流、电导率和zeta电位。当在 30 V 下处理时，由于其较高的电导率和 zeta 电位，污泥 C 的含水量达到最低。然而，污泥C较差的电渗效果导致其平均单位能耗较高。相比之下，提高外加电压对污泥C的电脱水过程更有效，但以更高的能耗为代价，而污泥A和B更倾向于通过延长脱水时间来提高电脱水效果。最后，通过实验证明了推导出的方程，可为实际应用提供指导。污泥的电导率和zeta电位。当在 30 V 下处理时，由于其较高的电导率和 zeta 电位，污泥 C 的含水量达到最低。然而，污泥C较差的电渗效果导致其平均单位能耗较高。相比之下，提高外加电压对污泥C的电脱水过程更有效，但以更高的能耗为代价，而污泥A和B更倾向于通过延长脱水时间来提高电脱水效果。最后，通过实验证明了推导出的方程，可为实际应用提供指导。污泥的电导率和zeta电位。当在 30 V 下处理时，由于其较高的电导率和 zeta 电位，污泥 C 的含水量达到最低。然而，污泥C较差的电渗效果导致其平均单位能耗较高。相比之下，提高外加电压对污泥C的电脱水过程更有效，但以更高的能耗为代价，而污泥A和B更倾向于通过延长脱水时间来提高电脱水效果。最后，通过实验证明了推导出的方程，可为实际应用提供指导。污泥C的电渗效果较差，导致其平均单位能耗较高。相比之下，提高外加电压对污泥C的电脱水过程更有效，但以更高的能耗为代价，而污泥A和B更倾向于通过延长脱水时间来提高电脱水效果。最后，通过实验证明了推导出的方程，可为实际应用提供指导。污泥C的电渗效果较差，导致其平均单位能耗较高。相比之下，提高外加电压对污泥C的电脱水过程更有效，但以更高的能耗为代价，而污泥A和B更倾向于通过延长脱水时间来提高电脱水效果。最后，通过实验证明了推导出的方程，可为实际应用提供指导。