Corrosion and Erosion-Corrosion Behaviors of Q235 and 5Cr1/2Mo in High Temperature Oil Containing Naphthenic Acid

摘要

Naphthenic acid corrosion (NAC) tests were carried out in a static corrosion apparatus to study the influence of temperature on NAC rate. Weight loss results indicated that increasing temperature aggravated NAC by the Arrhenius equation, while SEM results showed that NAC of Q235 was highly selective and pearlitic ferrite corroded preferentially. Naphthenic acid erosion-corrosion (NAEC) behavior as a function of fluid velocity (up to 50m/s) was studied by a jet impingement apparatus. The weight losses of quasi-static specimens located around the impingement specimen were also measured as comparison. Test results revealed that NAEC rate of Q235 increased with the square of the impinging flow rate. For 5Cr1/2Mo, there was a critical flow velocity around 30m/s above which NAEC rate increased greatly in oil with TAN of 14.5 mg KOH/g, while NAEC rate increased linearly with the flow rate in oil with TAN of 32.0 mg KOH/g. Quasi-static NAC rate of Q235 and 5Cr1/2Mo increased linearly with the actually flow rate.