燃煤锅炉烟气石灰石-石膏湿法脱硫废水成分复杂, 零排放治理难度较大。为达到资金、资源等投入与节能减排的综合效益, 对于化学沉淀等梯级处理技术的实际应用需综合考量处理效率与技术成熟度并对投资与长期运行费用进行评估, 从而确定合适的脱硫废水处理技术路线。基于燃煤锅炉石灰石湿法烟气脱硫废水的特性和相应的废水排放标准, 对脱硫废水的梯级处理技术进行综合分析, 深度讨论不同技术路线的特点及其适应性, 并结合实际应用的案例以探讨脱硫废水零排放处理技术的发展方向。在讨论脱硫废水特性的基础上, 介绍包括三联箱法、膜处理法、蒸发结晶技术及烟道蒸发技术在内的典型脱硫废水处理技术, 通过对不同技术的特点分析, 指出预处理能够去除废水中的污染物, 即对水的预处理是脱硫废水零排放处理的基础; 浓缩减量是降低能耗和成本的关键, 其可有效降低蒸发固化阶段的处理负荷和水的回收利用; 蒸发固化是实现零排放处理的核心, 其可以固体的形式固化脱硫废水中的杂质和盐分。通过对不同零排放工艺的应用分析及基于分级工艺的优化选择, 建议企业应根据脱硫废水水质特点和后续处理工艺对进水的要求以确定合适的零排放技术路线。未来应侧重于提高废水和矿物盐的综合利用率,强化不同工艺的优势组合是未来脱硫废水零排放的发展方向。

The composition of limestone⁃gypsum wet desulphurization wastewater from coal⁃fired boiler flue gas is complex, and it is difficult to control zero emission. In order to achieve the comprehensive benefits of investment,resources and energy conservation and emission reduction, for the practical application of cascade treatment technolo⁃gy such as chemical precipitation, the treatment efficiency and technology maturity should be considered comprehen⁃sively, and the investment and long⁃term operation cost should be evaluated, so as to determine the appropriate routeof desulphurization wastewater treatment technology. Based on the characteristics of limestone wet flue gas desulphuri⁃zation wastewater from coal⁃fired boilers and the corresponding wastewater discharge standards, the cascade treatmenttechnology of desulphurization wastewater was comprehensively analyzed, and the characteristics and adaptability ofdifferent technical routes were discussed in depth, the development direction of zero discharge treatment technology ofdesulphurization wastewater was discussed with practical application cases. On the base of discussing the characteris⁃tics of desulphurization wastewater, the typical desulphurization wastewater treatment technologies, including the tri⁃ple chamber method, membrane treatment method, evaporation crystallization technology and flue evaporation tech⁃nology, were introduced. By analyzing the characteristics of different technologies, it is pointed out that pretreatmentcan remove pollutants in wastewater, that is, the pretreatment of water is the basis of zero discharge treatment of de⁃sulphurization wastewater. The concentration reduction is the key part to reduce energy consumption and cost, it caneffectively reduce the treatment load and recycle water in the stage of evaporative solidification, which is the core ofzero⁃emission treatment, and can solidify the impurities and salts in the desulphurization wastewater in solid form.Through the analysis of the application of different zero emission processes and the optimization selection based on theclassification process, it is suggested that enterprises should optimize the classification process according to the char⁃acteristics of desulphurization wastewater quality and the requirements of subsequent treatment processes for influentwater, in order to identify appropriate zero emission technology routes. From the point of view of improving the com⁃prehensive utilization ratio of wastewater and mineral salts, it is clear that the development direction of zero dischargeof desulphurization wastewater in the future is to strengthen the superior combination of different processes.