碳钢和不锈钢在高温重质油中的腐蚀行为

Corrosion Behavior of Mild Steel and Stainless Steel in Heavy Oil at High Temperature

石油炼厂减二线油中含有少量的环烷酸,当温度高于200℃时,其中的环烷酸与高温活性硫的共同作用,加剧了金属设备的腐蚀。利用高压釜,以减二线重质油为介质进行动态腐蚀失重试验,考察了200～380℃内不同剪切速率下油品对Q235A、16Mn、Cr5Mo等三种低合金钢,18-8、304和316L不锈钢材料的腐蚀行为。发现低合金钢在相同温度下,Cr5Mo的腐蚀速率最小,且这33种低合金钢的腐蚀速率均在260℃左右出现一个局部极大值;当温度超过300℃后,它们的腐蚀速率再次随温度升高而增加;对于不锈钢,其腐蚀速率则随温度升高而单调增加,316L的耐蚀性最好。

Heavy oil from oil refinery plant contains a little naphthenic acid, thus the combined effect of naphthenic acid and active sulfur at high temperature will result in more serious corrosion of metal equipment as the temperature is higher than 200 ℃. The corrosion behaviours of three mild steels such as Q235A, 16Mn, Cr5Mo and three stainless steels as 18-8, 304, 316 L were investigated in heavy oil by dynamic autoclave test. The results show that the corrosion rate of Cr5Mo steel is the minimum at the same temperature compared to the other two mild steels, in addition the corrosion rates of three mild steels all appear a maximum at 260 ℃ or so, and increase again along with increasing temperature once the temperature is over 300 ℃. As for the stainless steel, the corrosion rates generally increase monotonically with temperature, and the corrosion resistance of 316 L stainless steel is best among steels that probably contributed to its higher molybdenum content.