燃煤电厂脱硫废水零排放处理技术比较

Comparison of zero-discharge treatment technologies for desulfurization wastewater in power plants

为了便于电厂选择合适的脱硫废水处理技术,详细介绍了蒸发结晶、主烟道蒸发、旁路热烟气蒸发等多种零排放技术,并结合工业应用实例比较了其优缺点。结果表明蒸发结晶技术运行情况良好,但其投运成本过高,投资成本约为250~350万元/(t·h),运行成本约为50~80元/t;主烟道蒸发技术投运成本最低,投资成本约为50~100万元/(t·h),运行成本约为10~20元/t,但其运行过程中存在诸多问题和风险,因此应用较少;旁路热烟气蒸发技术的投资成本约在100~250万元/(t·h),运行成本约为20~30元/t,相较于蒸发结晶技术投运成本有所降低,并解决了主烟道蒸发技术对锅炉效率影响大、影响机组安全运行的问题,总体来说,具有良好的应用前景;低温多效闪蒸浓缩技术和低温烟气旁路蒸发浓缩技术为脱硫废水浓缩技术,需与蒸发技术等结合实现脱硫废水零排放。

With the gradual strictness of domestic environmental protection policies,the zero-discharge of desulfurization wastewater from coal-fired power plants has become the trend of the times.In order to facilitate the power plant to choose the appropriate treatment technology,various zero-discharge technologies such as evaporation crystallization,main flue evaporation,bypass hot flue gas evaporation,etc.are introduced in detail,and their advantages and disadvantages are compared with industrial application examples.The results show that the evaporation crystallization technology is operating well,but its operating cost is too high,the investment cost is about 3.5million yuan/(t·h),and the operating cost is about 50~80yuan/t.The main flue evaporation technology has the lowest commissioning cost,the investment cost is about 0.5million~1.0million yuan/(t·h),and the operating cost is about 10~20yuan/t.However,there are many problems and risks in the operation process,so there are few applications.The investment cost of the bypass hot flue gas evaporation technology is about 1million to 1.5million yuan/(t·h),and the operating cost is about 20-30yuan/t.Compared with the evaporation and crystallization technology,the operation cost is reduced,and the main problem is solved.Flue evaporation technology has great impacts both on boiler efficiency and the safe operation of the unit.Generally speaking,it has a good application prospect;low-temperature multi-effect flash evaporation concentration technology and low-temperature flue gas bypass evaporation concentration technology are desulfurization wastewater concentration technologies,which need to be combined with evaporation technology to achieve zero discharge of desulfurization wastewater.