Naphthenic acid corrosion continues to be a reliability issue in refinery distillation units. A review of the subject is presented herein with special focus on field and laboratory data and on areas where research is needed. The review shows that several parameters are known to affect the corrosion process and their individual effect on crude corrosivity are somewhat understood. However, their combined effect is still subject to much controversy. The determination of a critical factor - naphthenic acid content ? is still not standardized. It is shown herein that, by arranging the literature findings into three groups (1) furnace tubes and transfer lines, (2) vacuum column and (3) side cut piping, a better agreement of the literature data is achieved.
High temperature corrosion of distillation units is a major concern to the refining industry. The presence of naphthenic acid and sulfur compounds considerably increases corrosion in the high temperature parts of the distillation units and equipment failures have become a critical safety and reliability issue. The difference in process conditions, materials of construction and blend processed in each refinery and especially the frequent variation in crude diet increases the problem of correlating corrosion of a unit to a certain type of crude oil. In addition, a large number of interdependent parameters influences the high temperature crude corrosion process. This paper presents a critical review of the open literature on high temperature crude corrosivity up to the year 1998.
