RESALT技术在燃煤电厂脱硫废水浓缩处理中的应用

Application of the RESALT Technology in the FGD Wastewater Concentration Processing of Coal-Fired Power Plant

基于电渗析技术的离子重组技术(简称RESALT技术)能够将废水中的钙离子和硫酸根离子分开,因而可避免形成硫酸钙垢,同时可实现废水的浓缩减量。在华电莱州发电有限公司现场进行了脱硫废水处理量为3~4m^3/h规模的RESALT技术中试研究。脱硫废水在RESALT装置中的运行结果表明,利用RESALT技术能够实现硫酸根离子和钙离子的有效分离,并且同时可实现含盐废水的浓缩处理,RESALT装置运行的电耗成本随进水含盐量及浓水含盐量的升高而升高,系统运行无须加药软化预处理,运行的成本主要为电费;以硫酸根、钙离子、镁离子、氯离子、钠离子质量浓度分别为6480mg/L、1820mg/L、2462mg/L、20680mg/L、10465mg/L的脱硫废水为例,系统回收率为70%,水处理电耗总计为49.5kWh/t,水处理直接成本为22.6元/t。

RESALT technology which is developed based on the Electric dialysis (ED) technology can effectively separate calcium ions from sulfate ions such that the scaling of CaSO4 is inhibited while the wastewater condensation process can be accomplished at the same time.The experiments were conducted in Huadian Laizhou power company with the inlet flow of the FGD wastewater about 3-4 m^3/h.The RESALT equipments were tested to treat three kinds of flue gas desulfurization (FGD) wastewater.The results show that sulfate ions could be efficiently separated from calcium ions and the high salt contained wastewater could also be concentrated at the same time.Since there is no additional chemical agents required for the wastewater pre-treatment,electricity consumption is the main component of the cost during the wastewater treatment process,which will rise as the salt concentration of the wastewater goes up.For example,with the concentrations of 6 480 mg/L of SO4^2-,1 820 mg/L of Ca^2+,2 462 mg/L of Mg^2+,20 680 mg/L of Cl and 10 465 mg/L of Na^+ in the FGD wastewater,the overall electricity consumption rate is 49.5 kW h per ton and the direct treatment cost is about 22.6 RMB/ton.