燃煤电厂脱硫废水零排放现场中试研究

Pilot scale research on zero discharge of desulfurization wastewater in coal power plant

燃煤电厂脱硫废水成分复杂,具有含盐量高、腐蚀性强、易结垢等特点,是电厂实现废水零排放的重点和难点。针对该废水的特点,采用“两级软化+过滤+高级氧化”预处理、“纳滤+碟管式反渗透”膜处理、“机械式蒸汽再压缩”蒸发结晶组合工艺进行了现场中试研究。结果表明,工艺运行稳定,膜系统产水及蒸发冷凝液均满足回用要求,回收的氯化钠达到工业盐标准,完全实现了脱硫废水零排放和资源化利用的目标。

Desulfurization wastewater from coal power plants is characterized by complex compositions,high salinity,strong corrosiveness and easy to cause scaling,and has become a key limiting factor for coal power plants to achieve zero discharge of wastewater.According to the characteristics of the wastewater,a combined process consisting of pretreatment(twostage softening,filtration and advanced oxidation),membrane treatment(nanofiltration and disctube reverse osmosis)and evaporationcrystallization(mechanical vapor recompression)was developed and tested in pilotscale.Results showed that the system operated stably.The membrane permeate and the evaporative condensate met the quality standards of reusing water,and the recovered NaCl met the standards of salt for industrial purpose.Finally,zero discharge of the desulfurization wastewater and resource recycling was fully realized.