Naphthenic acid corrosion is a significant problem in refineries. Naphthenic acid corrosion was reported first in 1920, and since then researchers and engineers have devoted much effort to study this corrosion phenomenon. A prevalent practice in the refineries is to use alloys of steel with one or more different metals to reduce the corrosion related destruction. To the best of our knowledge, however, no effort has been directed to study how the elements in these alloys corrode individually.In order to study naphthenic acid attack on these elements, crystal microbalance as an ultrasensitive in-situ method was used to study the corrosion behavior with a high time resolution. This technique allowed for precise determination of the behavior of the metals throughout the corrosion process, and thereby determining the effect of components in alloys. The alloying elements studied were iron, copper, molybdenum, chromium, cobalt, silicon, nickel, and zinc. Three weight percent naphthenic acid in a high purity base oil was used as a mock crude, and experiments were carried out in a custom made glass and Hastealloy autoclave. The in-situ corrosion data showed that these elements behaved quite differently when immersed in this high corrosive environment. Using the data from the crystal microbalance, FT-IR measurements from the test solution, and SEM images from the corroded surfaces, conclusions about the interactions between the acid and each of these elements were drawn. Copper, zinc, and iron corroded actively throughout the experiment, while the other elements were either inert, or reacted to form non-soluble corrosion products. These results can be used to develop new alloys or surface coatings to mitigate naphthenic acid corrosion refineries.

Crystal microbalance investigation of the corrosion of common alloying elements in oil with naphthenic acid

248th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.