化工进展 ›› 2017, Vol. 36 ›› Issue (S1): 482-488.DOI: 10.16085/j.issn.1000-6613.2017-0671

• 资源与环境化工 • 上一篇    下一篇

Mg2+对脱硫废水电解-电渗析过程的影响

杨博, 李玉忠, 崔琳, 李广培, 董勇   

  1. 山东大学燃煤污染物减排国家工程实验室, 山东 济南 250061
  • 收稿日期:2017-04-17 修回日期:2017-05-03 出版日期:2017-12-31 发布日期:2017-12-13
  • 通讯作者: 董勇,教授,研究方向为煤燃烧污染物控制理论与技术。
  • 作者简介:杨博(1991-),男,硕士研究生。

Influence of magnesium ions on electrolysis-electrodialysis process of desulfurization wastewater

YANG Bo, LI Yuzhong, CUI Lin, LI Guangpei, DONG Yong   

  1. National Engineering Laboratory of Coal-fired Pollutants Emission Reduction, Shandong University, Jinan 250061, Shandong, China
  • Received:2017-04-17 Revised:2017-05-03 Online:2017-12-31 Published:2017-12-13

摘要: 石灰石-石膏湿法脱硫工艺是应用最广泛的烟气脱硫技术,该工艺运行过程中会产生一定量的脱硫废水,脱硫废水中富集的氯离子会导致浆液的腐蚀性增加并且难以用常规的处理方法除去。电解-电渗析法是一种有前景的资源化处理方式,但是脱硫废水中的镁离子会影响系统的可靠运行。本文采用三室两膜电解装置以及不同镁离子浓度的CaCl2与MgCl2的混合溶液模拟实际的脱硫废水,进行了Mg2+对电解-电渗析影响的实验研究。实验结果发现,Mg2+浓度的增加会导致pH难以上升、槽电压升高及电耗增加等不利因素。脱硫废水中的Mg2+浓度大于0.179mol/L时,则需在电解前用化学沉淀法或其他合适方法控制Mg2+浓度以保证电解-电渗析系统的可靠运行。

关键词: 脱硫废水, 电解, 镁离子, 离子交换, 膜, 电耗

Abstract: Limestone-gypsum wet desulfurization process is the most widely used flue-gas desulfurization technology, this process produces a certain amount of desulfurization wastewater. The enrichment of Cl- included in desulfurization wastewater will increase the corrosivity of the slurry and they are difficult to be removed using conventional processing methods. The electrolysis-electrodialysis process is a promising recycling-treatment, but the Mg2+ included in desulfurization wastewater will influence reliable operation of the system. This paper adopted an electrolysis setup with three compartments and a pair of membranes and used a mixture of CaCl2 and MgCl2 at different concentrations of Mg2+ to simulate desulfurization wastewater, and proceeded to study the effect of Mg2+ during the electrolysis-electrodialysis process. Results show that the increase of the concentration of Mg2+ can make the electrolyte pH difficult to increase, increase the cell voltage and the energy consumption. When the concentration of Mg2+ is more than 0.179mol/L, the desulfurization wastewater should be pretreated by chemical precipitation or other suitable methods before electrolysis to ensure reliable operation of the electrolysis-electrodialysis system.

Key words: desulfurization waste water, electrolysis, magnesium ions, ion exchange, membranes, energy consumption

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