School of Mechanical & Electrical Engineering, Wuhan Institute of Technology, Wuhan 430000, China E-mail:
Water Sci Technol. 2021 Apr;83(7):1677-1690. doi: 10.2166/wst.2021.084.
Electrochemical water softening has been widely used in industrial circulating cooling water systems; however, their low deposition efficiency is the main drawback that limits usage in medium to large enterprises. In this work, the effect of different parameters on the hardness removal efficiency and energy consumption of the electrochemical water softening system is experimentally studied, and the performance of water softening applied by high frequency electric fields and direct current electric fields are comparative analyzed. The impact factors of the electrochemical water softening system are as follows: initial feed concentration of solute, magnitude of voltage, inter-electrode distance, area of cathode and frequency of power supply. To improve the analysis efficiency, the L (5) orthogonal table is used to investigate the five different factors at five levels. The experimental results are shown that the initial feed concentration of solute is the most significant factor affecting the hardness removal efficiency. The optimal combination for water softening in the group applied by high frequency electric field and direct current electric field are ABCDE and ABCD respectively. The energy utilization of the device applied by high frequency electric field is 3.2 times that applied by direct current electric field. The practice shows that direct current electric fields have a better softening effect, and are is more suitable for scaling ion removal. Particle image velocimetry (PIV) was used to observe the flow field induced by the electrolysis and found that the vertical and horizontal velocities of the flow field at low voltage are conducive to the migration of scaled ions to the cathode, and then the electrolytic reaction and deposition reaction synergy effect is the optimal.
电化学水软化已广泛应用于工业循环冷却水系统；然而，其沉积效率低是限制其在中大型企业中应用的主要缺点。在这项工作中，实验研究了不同参数对电化学水软化系统硬度去除效率和能耗的影响，并对高频电场和直流电场应用的水软化性能进行了比较分析。电化学水软化系统的影响因素如下：溶质初始进料浓度、电压大小、电极间距离、阴极面积和电源频率。为了提高分析效率，使用 L(5)正交表研究了五个不同因素的五个水平。实验结果表明，溶质初始进料浓度是影响硬度去除效率的最显著因素。在高频电场和直流电场应用组中，水软化的最佳组合分别为 ABCDE 和 ABCD。高频电场应用装置的能量利用率是直流电场应用装置的 3.2 倍。实践表明，直流电场具有更好的软化效果，更适合去除结垢离子。粒子图像测速（PIV）用于观察电解产生的流场，发现低电压下流场的垂直和水平速度有利于结垢离子向阴极迁移，然后协同作用促进了电解反应和沉积反应，这是最佳的。
