燃煤电厂全厂废水零排放改造工程设计及运行效果

Design and Operation Effect of a Wastewater Zero Discharge Reconstruction Project in Coal-fired Power Plant

某燃煤电厂为实现全厂废水零排放,在深度优化用水的基础上,对无法回用的循环排污水及脱硫废水进行处理。改造技术路线采用“循环排污水预浓缩+深度浓缩+旁路烟道雾化蒸发”工艺,循环排污水经预处理和多级浓缩后与脱硫废水一并处理,DTRO工艺作为深度处理工艺,最终通过旁路烟道蒸发系统实现盐-水分离。整套系统运行稳定,回收率、脱盐率高,结晶盐随着粉煤灰一同综合利用,不影响其在硅酸盐水泥中的掺配比例,解决了燃煤电厂循环排污水外排量大的难题。目前,整体系统运行成本较高(1568.1万元/a),其中膜处理系统药剂消耗成本占比近75%。

In order to realize zero discharge of wastewater in a coal-fired power plant,on the basis of deep optimization of wastewater,the circulating sewage and desulfurization water which can not be reused is treated.The process of“circulating sewage pre-concentration,deep concentration and bypass flue atomization evaporation”is adopted as the technological route of transformation.The circulating sewage is treated with desulfurization wastewater after pretreatment and multi-stage concentration,DTRO process is used as the advanced treatment process,and salt-water separation is finally realized through the bypass flue evaporation system.The whole system operates stably,with high recovery rate and desalting rate.The crystallization salt is comprehensively utilized along with fly ash without affecting its proportion in portland cement,which solves the problem of large external discharge of circulating sewage in coal-fired power plants.At present,the overall system operation cost is as high as 15.681 million yuan/a,among which the chemical consumption cost of membrane treatment system accounts for nearly 75%.