选择性电渗析处理火电厂脱硫废水

Treatment of Desulfurization Wastewater from Thermal Power Plant by Selective Electrodialysis

设计并开发得到了选择性电渗析系统,用于火电厂脱硫废水的浓缩处理。考察了浓缩过程中的离子迁移规律、能耗、电流效率和结垢情况,研究了浓水循环液和淡水循环液水质及水量对选择性电渗析效果的影响。结果表明,以恒电压模式(15.0 V)批次处理Cl浓度为4743~9092 mg/L的火电厂脱硫废水,Cl^(-)和重金属离子在浓水侧富集,但SO_(4)^(2-)不会发生大量迁移,选择性系数S^(Cl)_(SO4)保持在-1.05~-0.96范围内,电流效率可达0.70以上,平均能耗为1.39 kWh/kg(以Cl^(-)质量计),淡水循环液和浓水循环液的水质及水量对选择性电渗析效果几乎没有影响。应用该技术连续96小时处理火电厂高硬度脱硫废水,不会发生电渗析系统结垢,有潜力成为一种高效低成本的脱硫废水减量技术方案。

Selective electrodialysis system was designed and developed for the concentration treatment of desulfurization wastewater in thermal power plants.The ion migration,energy consumption,current efficiency and scaling in the process of concentration were investigated.The effects of water quality and water quantity on selective electrodialysis were studied.The results showed that when the desulfurization wastewater of the thermal power plant,with 4743~9092 mg/L of chloride ions,was treated in the constant voltage mode(15.0 V)batch,the chloride ions and heavy metal ions were enriched in the concentrated water side,but the sulfate ions did not migrate in large quantities,and the selectivity coefficient S^(Cl)_(SO4) remained in the range of-1.05--0.96,the current efficiency could reach above 0.70,and the average energy consumption was 1.39 kWh/kg(calculated by mass of Cl^(-)).The water quality and water quantity of produced water circulating liquid and concentrated water circulation liquid have little influence on the selective electrodialysis effect.The system can treat high hardness desulfurization wastewater of thermal power plants for 96 hours without scaling in the electrodialysis system,and it has the potential to be a high-efficiency and low-cost technology scheme for reducing desulfurization wastewater.