燃煤电厂脱硫废水烟气蒸发技术进展与应用

Development and application of flue gas evaporation technology for waste water desulfurization in coal-fired power plants

自"水污染防治行动计划(水十条)"颁布以来,燃煤电厂脱硫废水零排放已逐渐成为电厂深度减排、污染物深度治理的必然要求。脱硫废水烟气蒸发技术具有工艺简单、安全可靠、投资及运行成本低等优势,逐渐成为主流技术。燃煤电厂脱硫废水烟气蒸发技术主要分为3类:低温烟道蒸发、高温旁路烟气蒸发、低温烟气余热浓缩减量,其中高温烟气蒸发又可分为旁路蒸发塔蒸发和旁路烟道蒸发2种技术路线。同时,对电厂烟气蒸发能力进行了核算,论述了脱硫废水烟气蒸发技术的研究进展与应用现状,并深入分析了各烟气蒸发技术的工艺特性、优缺点及其适用范围。研究表明,燃煤电厂的烟气蒸发能力极强,可以作为脱硫废水零排放的热源。另外,低温烟道蒸发因其易受锅炉负荷影响,适用度不高,未来烟气蒸发技术的研究重点是低温烟气余热浓缩结合高温旁路蒸发或低温烟气余热浓缩结合水泥化固定。

Since the “Action Plan for Prevention and Control of Water Pollution” was promulgated,the zero-liquid discharge of desulfurization wastewater from coal-fired power plants has become an inevitable requirement for the deep wastewater treatment in power plants.Due to it simple process,higher safety &reliability and low investment and cost,evaporation technology using flue gas has become a main one in this field.Investigating the existing technologies,the flue gas evaporation technolog can be divided into three types:low-temperature flue evaporation,bypass high-temperature flue gas evaporation,and concentration and decrement using flue gas waste heat.The evaporation capacity of flue gas was calculated,the research progress of desulfurization wastewater evaporation technology was reviewed,and the process characteristics,advantages and disadvantages of each evaporation technology were analyzed deeply.It can be seen that flue gas evaporation capacity of coal-fired power plants is extremely strong and can be used as heat source for zero discharge of desulfurization wastewater.What's more,low temperature flue evaporation is not suitable due to its vulnerability of boiler load,the combination of concentration and decrement using flue gas waste heat with high temperature evaporation or solidification is one of research directions in future.This paper responds to the national policy actively,provides a reference for selection of zero-liquid discharge technologies in coal-fired power plants and has important practical significance and application value.