用焦化废水作补水的循环冷却水系统腐蚀控制实验研究

Experimental study on corrosion control using coking wastewater as circulating cooling water

焦化废水的排放会带来严重的水污染问题，迫切需要将其资源化，用作循环冷却水的补水是其资源化的重要途径。为了防止给循环冷却水系统带来腐蚀，根据水质稳定理论，采用静态和动态实验相结合的方法，研究了焦化废水作补水的循环冷却水系统腐蚀特性及控制技术。结果表明，焦化废水中的污染物造成的系统腐蚀以点蚀为主，应优先使用磷系沉淀膜型缓蚀技术。通过实验优选出的HEDP＋Zn^2＋复合配方，可在传热面上形成牢固的缓蚀膜，缓蚀率达到85．6％，普通碳钢的腐蚀速率为0．105mm／a，满足《工业循环冷却水处理设计规范》（GB50050-95）的要求。实际循环冷却水系统应用证明，使用该复合配方能在循环水浓缩倍数为2～2．2时，经济有效地解决系统的腐蚀问题，为焦化废水的资源化开辟了一条可行的途径。

The coking wastewater drainage will bring severe water environmental pollution, so it is necessary to change the coking wastewater into resource. The reuse of pre-treated coking wastewater as make-up water for circulating cooling system is an important way. To prevent the circulating cooling system corrosion, the characteristic and the corrosion control technology and the effect of the classic corrosion inhibitors in the circulating cooling water system were studied by static experiment zation theory. The results indicate that the corrosion and dynamic experiment based on water quality stabiliin circulating cooling system is mainly spot corrosion caused by pollutants in coking wastewater, and the corrosion inhibition technology on the model of precipitated membrane based on phosphor series should be preferred. The mixed corrosion inhibitors HEDP and Zn^2＋. optimally selected by experiment can form a firm corrosion inhibition membrane on heat transfer surface, and the corrosion inhibition rate could reach 85.6%. The corrosion rate of common carbon steel is 0. 105mm/a, which could satisfy the criterion of design criterion of the industrial circulating cooling water treatment （GB 50050- 95）. The practical application to the circulating cooling system shows that the mixed corrosion inhibitors HEDP and Zn^2＋ can control the corrosion in the system economically when the concentration multiple is 2-2.2, which opens up a feasible way for changing the coking wastewater into resource.