摘 要：介绍了现阶段水冷式冷凝器循环水系统中存在的金属腐蚀，水垢沉淀等问题，对其形成原因进行深入分析，并提出这些问题的处理方法及防护措施。
水冷式冷凝器需配置泵、冷水塔、蓄水池等循环水系统，因冷却水中含有钙、镁、氯等离子，当冷凝器运行一段时间后，不可避免地在冷凝器水侧结垢，水垢的存在，导致传热系数降低。此外，冷凝器冷却水为敞开式循环，暴露在大气中，由于水温升高，水分的蒸发，各种无机离子和有机物质浓缩、溶解氧的增多，将会腐蚀设备，缩短设备使用寿命。
一、循环冷却水系统腐蚀结垢原因分析
1.金属腐蚀
冷凝器及相关管道的主要材质为碳钢和铜。循环水系统的冷水塔和蓄水池都与大气相通，属于敞开系统，水中溶解了大量的氧。由于金属表面的不均一性和水中溶解的其他杂质具有导电性，在金属表面水膜中形成大量的微电池，从而发生了电化学腐蚀。
2.微生物及有害离子腐蚀
循环水中的微生物也会对金属产生腐蚀。这是由于微生物中的细菌和真菌分泌的酸、酶和多聚物与其他杂质等形成的污泥沉积在金属表面，形成微氧原电池，促使金属溶解腐蚀。此外，在循环过程中，水温升高，循环水中的氯化物和硫酸盐的浓度会浓缩增加，它们也会加速碳钢和铜的腐蚀。
3.水垢沉淀
在循环水系统中，各种盐类的浓度随着循环水的循环、蒸发浓缩而增加，当其浓度达到饱和状态，再经过水温较高的冷凝器传热表面时，有些难溶性 ca2 + 、mg2 + 就会析出。此外，循环水中的重碳酸盐很不稳定，在高温下容易分解生成难溶性物质。循环水流经冷水塔向下喷淋时，水中溶解的 co2气体逸出，促使碳酸钙、碳酸镁进一步生成，温度较高的循环系统，上述反应更为严重。因此，在冷凝器的换热面上，沉淀物会越积越多形成水垢，沉积的水垢导热系数一般不超过 1.16 w/m2k，远远小于碳钢和铜的导热系数，很大程度的降低了冷凝器换热面的传热效率。严重时，须停产检修，甚至更换冷凝器。
二、处理方法
1.高压水射流清洗冷凝器
高压水射流清洗技术作为物理清洗法之一，是近年来广泛应用于工业界的一种高科技清洗技术。高压水射流清洗技术具有清洗率高、速度快、成本低、不污染环境等优点。采用高压水射流清洗技术，可在不停机状态下，利用高压水射流清洗机喷射出的高压水流，清除冷凝器传热管内壁上的污垢和铁锈。清洗后的传热管基体无损伤、无腐蚀，无漏制冷剂现象发生。 2.臭氧净化循环水
欧美等发达均大力推广使用环保型强力杀菌剂臭氧，臭氧以氧原子的氧化作用破坏微生物膜的结构，以实现杀菌作用。臭氧作为水处理剂，具有操作简单，排污量少，既能节水节能，又不存在二次污染等优点，对循环水的缓蚀、阻垢、杀菌等方面均有良好的效果。但该方法初投资较大，在实际的循环水应用中较少。
3.循环水的硬水软化
硬水软化的方法包括离子交换法，膜分离法，石灰法，电磁法等。其中，离子交换法是常用的方法，是以钠离子将水中的难溶性钙镁离子置换出来，因为钠盐的溶解度很高，所以避免了随温度的升高而造成水垢的生成。该方法工艺成熟，效果稳定准确，已经在循环水的前处理有广泛应用。
4.添加快效绿色缓蚀阻垢剂
循环水中添加快效绿色缓蚀阻垢剂也是现代工业主要的处理方法之一，其机理是缓蚀阻垢剂通过螯合与分散作用达到缓蚀阻垢的目的。缓蚀阻垢剂，能够有效控制循环水化学腐蚀，具有良好的杀菌、灭藻、阻垢功效，在制冷等行业的循环水系统中有广泛的应用。
参考资料：水冷式冷凝器循环水系统腐蚀结垢问题及处理——苏超
产品英文详情介绍
abstract: metal corrosion, scale precipitation problems stage water-cooled condenser circulating water present in the system, and their formation in-depth analysis, and proposed treatment and protective measures to these problems. water-cooled condenser to be configured pumps, cooling towers, reservoirs and other circulating water systems, due to the cooling water contains calcium, magnesium, chlorine plasma, after a period of operation the condenser, the water inevitably fouling of the condenser, scale presence, resulting in reduced heat transfer coefficient. in addition, the condenser open recirculating cooling water, exposed to the atmosphere, since the water temperature, the evaporation of water, various inorganic ions, and organic material was concentrated, dissolved oxygen increases, corrosion of equipment would shorten the life of the device. a, corrosion and scaling reasons cooling water system 1. analysis of the main material and associated condenser metal corrosion of carbon steel and copper pipes. cooling tower circulating water system and the reservoir are in communication with the atmosphere, is an open system, a large amount of oxygen dissolved in water. since other impurities were dissolved in water and a non-uniform surface of a conductive metal, forming a large number of micro film of water on the metal surface of the battery, so that galvanic corrosion occurs. 2. microorganism and harmful ion etching circulating water will cause corrosion of metals. this is due to the formation of sludge deposited microorganism bacteria and fungi secrete acids, enzymes and polymers and other impurities on the metal surface, an oxygen atom form a micro cell, promote corrosion of metal dissolution. moreover, during cycling, water temperature, increase the concentrations of chloride and sulphate and concentrated circulating water, they also accelerate the corrosion of steel and copper. 3. scaling deposits in the circulating water system, the concentration of various salts as the circulating water loop, and concentrated by evaporation increases when the concentration reaches saturation, then after high temperature when the heat transfer surface of the condenser, some difficulty soluble ca2 +, mg2 + will precipitate. in addition, circulating bicarbonate in water is very unstable, easily decomposed at high temperatures formation of insoluble substance. circulating water through the cold water shower down column, the dissolved co2 gas to escape, causes calcium carbonate to generate a further, higher temperature cycle system, wherein the reaction is more severe. thus, the heat exchange surface of the condenser, will precipitate piled scale formation, scale deposition thermal conductivity of not more than 1.16 w / m2k, far less than the thermal conductivity of carbon steel and copper, is considerably reduced heat transfer efficiency of the heat transfer surface of the condenser. in severe cases, to be maintenance shutdown, or even replace the condenser. second, the processing method of high pressure water jet cleaning condenser pressure water jet cleaning technology as one of the physical cleaning method, is widely used in recent years, a high-tech industry cleaning technology. pressure water jet cleaning techniques have cleaning rate, high speed, low cost, no environmental pollution and other advantages. high pressure water jet cleaning technology, in the non-stop state, the high pressure water jet cleaning injected high-pressure water to remove dirt and rust on the tube wall heat transfer condenser. the heat transfer tube after cleaning the substrate no damage, no corrosion, no leakage of the refrigerant occur. 2. ozone purifying circulating water europe and other developed are to promote the use of environmentally friendly powerful bactericide ozone, oxidation by oxygen atoms damage the structure of microbial membranes, in order to achieve sterilization. ozone water treatment agent, simple operation, less pollution, both water and energy saving, without the presence of secondary pollution, corrosion aspects of the circulating water, scale, have good sterilization effect. however, this method a large initial investment, less water circulating in practical applications. 3. the method of circulating the water softening water softening water include ion exchange, membrane separation, lime method, an electromagnetic method. wherein the ion exchange method is a commonly used method, is poorly soluble sodium calcium and magnesium ions displaced, because of the high solubility of the sodium salt, it is avoided with the temperature caused by scale formation. the method of mature, stable and accurate results, pretreatment of the circulating water has been widely used. 4. add as rapid onset green corrosion inhibitor is one of the major industries of modern fast onset treatment green circulating water corrosion and scale inhibitors, corrosion inhibitors whose mechanism of chelation and dispersion reached by corrosion barrier scale purposes. corrosion inhibitors, can effectively control the circulating water chemical corrosion, it has good sterilization, algae, scale effect, is widely used in refrigeration and other industries in the circulating water system. references: water-cooled condenser circulating water system corrosion and fouling problems processing - spl
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