A corrosion failure analysis of tubes in 138C dilution steam generator of ethylene unit for Lanzhou petrochemical company was carried out.The results showed that the uniform corrosion characteristic was observed on tubes,on the condition of 170℃,the corrosion failure were engendered by oxygen absorption corrosion、sulphur corrosion and Cl-catalysis corrosion,moreover,Cl-accelerated the corrosion process;in addition,some improvement suggestions were pointed out.

In order to select a proper material for the circular disposal acid pump in the aniline unit, the weight-loss method, SEM and EDS techniqus were adapted to study the anticorrosive properties of Hastelloy C alloy, 804 alloy, 20 alloy, 904L and 316L stainless steels in the circular disposal acid at 80 °C. The results showed that except Hastelloy C alloy, the other four kinds of alloys had excellent anticorrosive properties in the circular disposal acid at 80 °C.

通过不同稳定剂对酸性化学镀液稳定性、镀速以及使用周期影响情况的试验考查,发现用量为4～5 mg/L的复合型稳定剂稳定效果优于单一稳定剂;在同样施镀条件下,添加复合稳定剂后使用周期由原来的4～5个周期提高到8～9个周期.

The serious corrosion problem has appeared on the heat-exchanger used for electric desalting in the delayed cooking unit of Khartoum Refinery Company.Many reasons,including analysis of the technical medium,corrosion appearance,energy-chart of X-ray and products of corrosion,have been analyzed.The results indicate that the shell of the heat-exchanger is destroyed by bacteria corrosion and under-deposit corrosion.The pipe monitor of the heat-exchanger is scathed by uniformity corrosion which arised from de-calcification agent.A right corrosion protection measures are suggested in the end.

Analyzed in this paper are the drawbacks of every single anti-corrosion technology for the heat exchanger in refinery. The laboratory study of the synergistic effect of seven anti-corrosion technologies including coating-cathodic protection, chemical plating-cathodic protection, corrosion inhibitor-coating, corrosion inhibitor-chemical plating, corrosion inhibitor-corrosion resistant metal material, corrosion resistant-cathodic protection and inter-corrosion inhibitor are carried out. The study results indicate that after all the anti-corrosion technologies are applied synergistically, both the technical index and economical index are increased by tens or hundreds of times. The synergistic effect is the effect of "one plus one is bigger than two". Subsequently, two industrial tests are performed and the same good technical and economical effects are obtained.

A discussion is made of several kinds of organic nonmetallic tubing materials,which are commonly applied in petrochemical industry unit.By comparing the physical mechanical capacity and corrosion proof capacity,combining the practical application of nonmetallic tubing in Lanzhou petrochemical complex,the application scopes and the localization of these tubing materials are synthetically analyzed.In the end,the especial capacity of CPVC is discussed emphatically,with the hope to offer some reference for chemical industry to select tubing material rationally according to the corrosible circumstances.

兰州石化公司6座大容量原油储罐的罐底板相继穿孔泄漏.通过分析指出为Cl-引起的电化学腐蚀所造成.在2000～2001年期间,对3座原油罐的罐底板及距底1.5mm以上的罐壁采取了环氧玻璃鳞片涂料+铝合金牺牲阳极联合保护,其保护电位可稳定在-9.0～1.00V范围.文章对罐底板保护电位的监测方法也进行了介绍.

通过对兰州石化公司分子筛高低碱反应罐的腐蚀进行检测分析,发现高低碱罐失效主要是由于碱在高温、高浓度作用下的沿晶型应力腐蚀开裂造成的.更新材质并采用外加电流阴极保护措施后,效果良好.

针对兰州炼油厂原油罐底板腐蚀泄漏情况严重的问题,对三具原油罐底板的腐蚀情况做了检测及原因分析.原油罐底板的腐蚀形貌主要是点蚀和溃疡腐蚀,其中点蚀是由罐底污水中的氯离子造成的,而溃疡腐蚀是由原油污泥形成的垢下腐蚀造成的.针对原油罐腐蚀特性,经过实验,提出了铝牺牲阳极电化学保护与涂刷耐腐蚀涂料相结合的防护措施.实时监测所得的罐底板电位始终处于-0.85～-1.0V范围内,表明原油罐底板的腐蚀得到了有效控制,底板与电极接触可靠,达到了原油罐长效防护,炼油厂原油安全储运之目的.