Comparative analysis the performance of electrochemical water softening between high frequency electric fields and direct current electric fields based on orthogonal experimental methods.

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.