湿法脱硫废水液柱蒸发特性

Evaporation characteristics of wet desulfurization wastewater in liquid column form

提出了一种利用烟气余热基于液柱蒸发浓缩脱硫废水的新型工艺,旨在降低脱硫废水零排放的成本。利用液柱蒸发试验台,研究了不同工艺参数下脱硫废水的液柱蒸发特性,得到了出口烟气湿饱和的边界条件。研究结果表明:在试验参数范围内,烟气裹挟速率、蒸发速率、压力损失范围分别为1.5~53.17kg/h、8.85~45.73kg/h、9~160Pa,出口烟气湿度、出口烟气温度、SO2去除率范围分别为28.6%rh^99.6%rh、42.5~65.7℃、4.1%~61.0%。出口烟气中盐离子浓度的增加为烟气裹挟废水所致,蒸发过程中盐类不会迁移到烟气中。喷嘴直径为2.5mm时,出口烟气均呈湿饱和态;喷嘴直径为5mm时,蒸发塔内烟气流速大于5.0m/s时,出口烟气呈湿饱和态;喷嘴直径为10.6mm时,出口烟气均呈不饱和态。本实验的实施对于电厂的余热利用和废水零排放项目提供了参考和借鉴意义。

A new technology of concentrating desulfurization wastewater based on liquid columnevaporation using the waste heat of flue gas was proposed in this study,which can reduce the cost ofwet desulfurization wastewater zero discharge.The liquid column evaporation test-bed was establishedand the evaporation characteristics of wet desulfurization wastewater in liquid column form werediscussed.The boundary conditions of wet-saturated outlet flue gas were determined.Experimentalresults showed that in selected range of operating parameters,the range of the carrier rate,evaporationspeed and pressure loss are1.5-53.17kg/h,8.85-45.73kg/h,9-160Pa,respectively.The range of theoutlet flue gas humidity,outlet flue gas temperature and removal efficiency of SO2are28.6%-99.6%,42.5-65.7℃,4.1%-61.03%,respectively.The salts do not migrate into the flue gas during liquidcolumn evaporation.Meanwhile,the carrier of flue gas increases the concentration of salts in outlet flue.The outlet flue gas is wet-saturated when the nozzle diameter is2.5mm,and it is the oppositewhen the nozzle diameter is10.6mm.Only when flue gas speed is greater than5.0m/s,the outlet fluegas is wet-saturated when the nozzle diameter is5mm.This study provides experiences and referencesof power plant wet desulfurization wastewater with waste heat utilization and zero discharge.