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电化学法硬水处理性能的实验研究
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Abstract:
在工业生产中，换热器壁面结垢会导致能源和水资源利用效率下降，设备寿命缩短。现有除垢技术存在效率低、能耗高和二次污染问题。本研究开发了一套电化学水处理装置，利用低压电场控制硬水离子，实现成垢离子的选择性结晶析出。该技术高效、操作简单、成本低且环保。本研究对处理速率、硬度去除效率以及单位能耗等关键指标展开系统考察，剖析操作参数发生变化时，其对电化学水处理工艺综合性能所产生的作用机制，采用去离子水与CaCl2、NaHCO3配制的冷却水，研究了电化学法处理冷却水时去除硬度的特性以及电流密度、极板间距及停留时间3种影响因素对装置去除硬度效果的影响情况。研究表明，当运行条件(电流密度、极板间距及停留时间)一定时，装置连续运行3 h，硬度去除率基本保持稳定，即其降低硬度的性能不会随时间的延长而发生明显变化；当电流密度为30 A/m2、极板间距为4 cm，装置能较好地降低冷却水的硬度，且极板腐蚀程度较低。
In industrial production, scaling on the walls of heat exchangers can lead to reduced efficiency in energy and water resource utilization, as well as shortened equipment lifespan. Existing descaling technologies suffer from low efficiency, high energy consumption, and secondary pollution issues. This study developed an electrochemical water treatment device that uses a low-voltage electric field to control hard water ions, achieving selective crystallization and precipitation of scale-forming ions. The technology is efficient, easy to operate, low-cost, and environmentally friendly. This research systematically examined key indicators such as treatment rate, hardness removal efficiency, and unit energy consumption, analyzing the mechanisms by which changes in operating parameters affect the overall performance of the electrochemical water treatment process. Deionized water mixed with cooling water prepared with CaCl2 and NaHCO3 was used to investigate the characteristics of hardness removal during electrochemical treatment of cooling water, as well as the effects of three influencing factors: current density, electrode spacing, and residence time. The study found that when operating conditions (current density, electrode spacing, and residence time) are constant, the hardness removal rate remains stable over continuous operation for 3 hours, meaning its ability to reduce hardness does not significantly change over time. When the current density is 30 A/m2, the electrode spacing is 4 cm, the device can effectively reduce the hardness of cooling water, with minimal electrode corrosion.
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