高酸原油的腐蚀评价、预测及选材研究

本文采用高温动态腐蚀评价装置模拟炼厂实际工况,通过开展高酸原油腐蚀评价,采用数理统计方法分别拟合20G、1Cr5Mo、0Cr13、321和316L等材质的腐蚀速率与温度之间的关系曲线和计算公式;该系列曲线用于预测温度250~350℃、流速15~30 m/s、酸值2~4 mgKOH/g,硫质量分数小于0.3%范围内高酸原油的腐蚀性能。研究结果表明,20G碳钢和1Cr5Mo在高温环烷酸腐蚀环境下的耐蚀性能较差;0Cr13和321两种材质的耐蚀性能相差不大,当温度超过300℃时两种材质的腐蚀速率随温度的升高快速增加,因此在高于300℃的部位不考虑使用0Cr13和321;316L具有优良的抗高温环烷酸腐蚀,在加工高酸原油的高温、高流速或塔内填料等部位均应考虑使用316L不锈钢,并要求其Mo质量分数大于2.5%。

Corrosion Evaluation,Prediction and Material Selection for Processing High- TAN Crude Oil

A high -temperature dynamic corrosion experiment equipment has been successfully developed tbr simulating the real refining corrosion environment. With the corrosion evaluation of high - TAN crude oils, the prediction curves and their calculation formula of 20G, 1CrSMo, 0Cr13, 321 and 316L steels were fitted respectively by using mathematical statistics method. The curves were applicable for the corrosion prediction of high -TAN crudes of 250 - 550 ℃ temperature, 15 -30 m/s velocity, 2 - 4 mgKOH/g acid value and lower than 0.3 wt% sulfur. The results indicated that corrosion resistant performances of 20G and 1CrSMo in naphthenic acid were poor. The corrosion resistant performance of 0Cr13 and 321 steels were similar. When the temperature exceeds 300℃, the corrosion rates of the two materials went higher with rising temperature. They shouldn＇ t be considered in the service with temperature higher than 300℃. 316L steel had excellent resistance to naphthenic acid corrosion. Therefore, the application of 316L steel should be considered in the high -temperature, high -velocity sections or tower packing, and the Mo content of 316L steel should be no higher than 2.5%.