零排放形势下热电厂脱硫废水处理进展及展望

Status and Prospect of Zero Liquid Discharge Technologies for Flue Gas Desulfurization Wastewater in Thermal Power Plant

针对国内愈益严格的环保政策及逐渐深入的零排放形势,结合脱硫废水的水质和主要问题,综述了热电厂脱硫废水的传统处理工艺和零排放工艺的研究与应用现状。脱硫废水具有高悬浮物、高盐、水质复杂、波动大等特征,传统处理工艺主要存在效果不稳定、产水不达标、结垢腐蚀严重和浓盐水排放问题。简述了脱硫废水传统处理工艺及其改进工艺的研究与应用现状,指出其在零排放形势下已不满足处理要求,而逐渐转换为预处理工艺。重点论述了零排放组合工艺的预处理、重金属去除、浓缩减量和盐结晶固化单元工艺的研究与进展,总结了目前脱硫废水零排放技术的发展进程,并分析总结了若干典型应用案例,指出"膜分离+蒸发结晶"组合工艺将会成为深度处理与零排放的关键工艺。零排放是未来热电厂脱硫废水处理的主要途径,亟需加快新材料、新装备、新工艺等在脱硫废水零排放的工业化应用进程。

The application and research status of flue gas desulfurization wastewater(FGDW) treatment technologies were reviewed under the more and more strict environmental policies and the intensive requirements of zero liquid discharge(ZLD) in China. With high suspend solids(SS), high salinity, complicated composition, and significant fluctuation of the FGDW, conventional treatment technologies of the FGDW face big challenges such as unstable performance which cannot meet with the discharge standard, serious scaling and corrosion issue, and concentrate discharge, etc. The application of conventional treatment technologies and their improved processes were mainly reviewed, which cannot meet with the standard and have been transferred to pretreatment process in ZLD application. Then the ZLD technologies for FGDW and their development trend were carefully reviewed in terms of pretreatment process, heavy metal removal processes, wastewater concentration and reduction technologies, and salts crystallization technologies. And the research & development of ZLD technologies for FGDW wastewater and some typical application cases of ZLD project were summarized, and the combination of membrane separation, evaporation and crystallization will be the key technologies for the ZLD of FGDW treatment. It was believed that ZLD treatment would become the major approach in the ZLD of FGDW, and the development of new materials, equipments, and technologies will promote the industrial application of ZLD project for FGDW in thermal power plant.