乙烯碳五分离装置冷凝器的腐蚀及防护措施

Corrosion of Condenser in C5 Separator of Ethylene Plant and Prevention Measures

某大型乙烯工厂的碳五分离装置脱轻塔冷凝器在停工检修时发现管束出现大量的穿孔泄漏。通过对设备附着物的化学分析和设备工况条件分析,得出结论:冷凝器管束的泄漏原因为腐蚀穿孔泄漏。影响腐蚀的主要因素有壳程工艺介质冷却水水质不良、流速缓慢、设备腐蚀防护措施欠缺等。在此基础上,提出了控制管束腐蚀的措施,一是改善水质,采用混凝、沉清、过滤等方法,去除原水中泥沙、虫类、微生物等悬浮杂质,加强补充水的处理,做好循环水旁流过滤;二是合理控制循环水流速,应保障循环冷却水管程流速不小于0.9 m/s;壳程流速不小于0.3 m/s;三是实施材料防腐蚀措施,可采取有机涂层防腐、金属或合金镀层防腐、材质升级等方式,提高设备的耐蚀能力。

A large amount of rupture leaking was found during the shutdown for maintenance of the condenser in stripper of C5 separation unit of a large ethylene plant. The analysis of chemical compositions of attachment on the equipment and equipment operating conditions concludes that the leaking of the condenser tubes is corrosion rupture leaking. The main factors ＇affecting the corrosion are poor cooling water quality for the media at the shell side, slow flow velocity and insufficient corrosion prevention measures, etc. Effective corrosion control measures have been proposed such as （ 1 ） improvement of water quality by mixed condensing, settlement and filtration, etc to remove the sands, insects and microorganisms, etc from water. Make - up water treatment and cooling water filtration are under strict control; （2） The flow velocity of eooling water are appropriately controlled to ensure that the velocity of cooling water inside the tube side is no lower than 0.9 m/s and that inside the shell side is no lower than 0.3 m/s; （3） material corrosion protection measures are adopted such as application of organic coatings, metal or .alloy coatings, material upgrading, etc to improve the corrosion resistance of equipment.