摘要
受沉淀速率的限制,电化学软化技术投资成本较高,阻碍了其大规模推广应用。对此,本文采用超声辅助的平板电极反应器对循环冷却水进行软化处理,并对其软化性能进行实验研究。实验结果显示:超声辅助能够加速成垢离子的传质过程,使CaCO_3的沉淀速率随着电流密度的增加而提高,不再受限制;电流密度为140 A/m^2,超声强度为1.8 W/cm^2时,CaCO_3的沉淀速率可达39 g/(m^2·h);超声强度大于2.5 W/cm^2时,CaCO_3的沉淀速率的提高不明显;相比于无超声条件,超声条件下阴极表面的沉淀物尺寸小且排列疏松,有利于沉淀速率的提高及沉淀物的清除;阻垢剂对沉淀反应过程存在不利影响,因此不宜与超声辅助同时使用;经过10个周期的实验,平均沉淀速率无明显波动,说明超声辅助电化学反应器具有良好的运行稳定性。该结论可为提高循环冷却水电化学软化性能提供参考。
The large-scale application of electrochemical softening technology is severely hindered by its high investment cost due to the limitation of precipitation rate.In view of this question,an ultrasonic-assisted reactor with flat electrodes was employed for the softening treatment of circulating cooling water,and its softening performance was systematically investigated.The results show that,ultrasonic assistance accelerated the mass transfer process of scaling ions,thus made the precipitation rate rise without restriction as the current density increased.A high precipitation rate of 39 g/(m^2·h)could be obtained at the current density of 140 A/m^2 and ultrasound intensity of 1.8 W/cm^2.When the ultrasound intensity was larger than 2.5 W/cm^2,the precipitation rate would not be significantly improved.The diameters of the precipitates arranged loosely on the cathode surface were much smaller under ultrasonic condition than that of silent condition,which was conducive to the improvement of precipitation rate and removal of precipitates.Moreover,scale inhibitors should not be used together with ultrasonic assistance ascribed to their negative effect on precipitation reaction process.After 10 cycles of experiments,the average precipitation rate exhibited no obvious fluctuation,indicating that the ultrasound-assisted electrochemical reactor showed good operation stability.The conclusions provide valuable reference for improving electrochemical softening performance in circulating cooling water.
作者
陈东
曹顺安
曾玉彬
申震
CHEN Dong;CAO Shun’an;ZENG Yubin;SHEN Zhen(School of Power and Mechanical Engineering,Wuhan University,Wuhan 430072,China;Datang Central-China Electric Power Test Research Institute Co.,Ltd.,Zhengzhou 450000,China)
出处
《热力发电》
CAS
北大核心
2020年第2期24-29,共6页
Thermal Power Generation
关键词
循环冷却水
电化学
软化
超声
CaCO_3
沉淀速率
运行稳定性
经济性
circulating cooling water
electrochemistry
softening
ultrasound
CaCO3
precipitation rate
operational stability
economy
