火电机组脱硫废水处理工艺中的影响因素研究

Study on the Influencing Factors in the Desulfurization Wastewater Treatment Process of Thermal Power Units

火力发电厂的燃烧废气必须脱硫脱硝才能排放,国内外电厂的脱硫工艺各不相同。综述了国内外火力发电厂含硫废水处理工艺,针对蒸发环节的影响因素进行了比较和研究,分析了目前的工艺的优缺点。废水中氯离子浓度控制方法以控制废水的pH值为主,采用电解制氯技术耦合以提高综合效益。目前采用的烟道气作为热源对脱硫废水蒸发的工艺,温度是关键,低于315℃时产生挂壁现象。蒸发工艺选择要结合地理环境,东部地区以多种膜处理工艺联用为主,尽量实现零排放。西部地区利用阳光充足、气候干燥的特点进行自然蒸发。针对废水蒸发导致水资源无法回收利用的难题,在干旱和半干旱地区,采用蒸汽机械再压缩降膜蒸发结晶与烟气旁路蒸发联用技术,或者利用电厂尾部低温烟气真空蒸发,把蒸发的水蒸气经扩容后变成蒸馏水回用以解决水循环利用的难题。针对蒸发法对烟气和系统管道的影响进行了分析,结合传统的三联箱技术,因地制宜,选择成本可以接受的方法进行处理,满足目前的需要,但是要实现整个火电行业脱硫废水零排放还要继续攻关。

The combustion exhaust gas of thermal power plants must undergo desulfurization and denitrification before it can be discharged,and the desulfurization processes vary between domestic and international power plants.This article summarizes the sulfur-containing wastewater treatment processes in thermal power plants both domestically and internationally,compares and studies the influencing factors of the evaporation process,and analyzes the advantages and disadvantages of current processes.Controlling chloride ion concentration in wastewater primarily involves adjusting the wastewater's pH level,and integrating electrolytic chlorination technology to enhance efficiency.The current process of using flue gas as a heat source for the evaporation of desulfurization wastewater relies heavily on temperature,with wall hanging occurring below 315℃.The selection of evaporation process should be combined with geographical environment.In the eastern region,multiple membrane treatment processes are mainly used in combination to achieve zero emissions as much as possible.The western region utilizes the characteristics of abundant sunshine and dry climate for natural evaporation.In response to the problem of water resources being unable to be recycled due to wastewater evaporation,in arid and semi-arid areas,the combination of steam mechanical recompression falling film evaporation crystallization and flue gas bypass evaporation technology is adopted,or the low-temperature flue gas vacuum evaporation at the tail of the power plant is used to expand the capacity of the evaporated water vapor and convert it into distilled water for reuse to solve the problem of water recycling.An analysis was conducted on the impact of evaporation method on flue gas and system pipelines,combined with traditional triple box technology.Based on local conditions,an acceptable cost method was selected for treatment to meet current needs.However,further research is needed to achieve zero discharge of desulfurization wastewater in the entire thermal power industry.