Role of Corrosion Products by the Sulfidation of Aisi/sae-1020 Steel in Heavy Crude Oil at High Temperatures

Abstract

The effect of temperature and exposure time on the formation of corrosion products on AISI/SAE-1020 steel was determined at typical service conditions of a transfer line that enters into an atmospheric distillation tower for processing heavy crude oil. The corrosion rate of the investigated material was determined in 12.2°API crude oil having 2.5%w/w of sulfur by weight loss measurements. The temperature and exposure time were varied in this study between 250 and 320°C, and between 36 and 504 hours, respectively. Corrosion products formed at the steel surface were characterized using scanning electron microscopy (SEM) combined with x- ray energy dispersive spectrometry (EDS) and x-ray diffraction (XRD). The obtained results have shown that both variables temperature and exposure time strongly influence the formation and stabilization of the corrosion products mainly iron sulfides formed at the steel surface being in contact with the high sulfur containing crude oil. After a period of stabilization, these corrosion products act as a physical barrier against corrosive species in the system thus reducing the corrosion rate of the investigated material.