Chapter 6 - Corrosion Inhibitors

Abstract

Corrosion inhibitors, which are used for the protection of oil pipelines, are often complex mixtures. Majority of inhibitors used in oil production systems are nitrogenous and have been classified into broad groupings—namely, (1) amides and imidazolines, (2) salts of nitrogenous molecules with carboxylic acids (fatty acids, naphthenic acids), (3) nitrogen quaternaries, (4) polyoxylated amines, and (5) nitrogen heterocyclics. For oil storage tanks, volatile corrosion inhibitors are an excellent solution from both technical and economic standpoint. These inhibitors provide corrosion protection under wet conditions and void spaces. In oil wells, Inhibitors must be injected into the borehole to increase the life of well casing, flow lines, and equipment of unalloyed and low-alloyed steels in corrosive media. The preparation of a corrosion inhibitor in the solid form also allows the development of a new technique of continuous intensive anticorrosive protection for gas and oil pipelines, as well as for acidizing operations of oil wells. The controlled dissolution of the solid inhibitor creates a thin protective layer on the metallic surface that prevents or minimizes the undesirable corrosion reactions.