低温多效海水淡化铝合金换热管的清洗及保护

利用X射线荧光光谱、旋转挂片腐蚀模拟实验、现场水质分析、传热管表面宏观形貌分析等技术手段,针对国内某低温多效海水淡化系统铝合金换热管的结垢问题开展了清洗介质筛选及酸洗缓蚀剂研究,并进行了工程现场实际应用。结果表明,现场铝合金换热管表面结垢以CaCO3及CaSO4为主;采用氨基磺酸进行酸洗可有效清除垢层,酸洗缓蚀剂能显著降低铝合金腐蚀速率,实验室缓蚀效率达到94.14%,现场应用缓蚀效率达到90%;现场水质监测可有助于判断酸洗终点,防止设备过洗。结论,以氨基磺酸为清洗介质可有效清除铝合金换热管表面CaCO3及CaSO4垢,酸洗缓蚀剂对铝合金有明显的保护作用,现场应用取得了优良的清洗效果。

Cleaning and Protection of Aluminum Alloy Heat Exchanger Tube in Low Temperature Multieffect Seawater Desalination System

To investigate the chemical cleaning and protection technology of aluminm alloy heat exchanger tube in low temperature multieffect desalination system, X-ray fluorescence spectroscopy(XRF), rotary coupon corrosion test, in-situ water quality analysis and macroscopic surface morphology of heat exchanger tube were carried out. The selection of cleaning agent and corrosion inhibitor was studied and applied in the field to solve the scaling problem of aluminum alloy heat exchange pipe in a domestic low temperature multieffect seawater desalination system. The results show that, the main components of heat exchange tube scaling are Ca CO3 and Ca SO4, and it can be cleaned efficiently with sulfamic acid companied with inhibitor which can reduce the corrosion rate of aluminm alloy. The inhibition efficiency is 94.14% in the lab and 90% in the field. In-situ water quality analysis can help determine the end point of cleaning and prevent the equipment from overwashing. The conclusion is that Ca CO3 and Ca SO4 scale on the aluminum alloy heat exchanger tubes can be effectively removed by using sulfamic acid as cleaning agent, and corrosion inhibitor has obvious protective effect on aluminum alloy with which good cleaning effect is obtained by field application.