Corrosion inhibitors have widespread use in the crude oil refining industry for corrosion protection and mitigation. Over the years, certain classes of inhibitors have been established as industry standards to confront specific corrosion mechanisms encountered throughout the refinery process. Although alkaline carbonate stress corrosion cracking (ACSCC) has been a well-documented corrosion mechanism found in the overheads of fluid catalytic cracking units (FCCU), gas separations units (GSU) and sour water strippers (SWS), there is a lack of inhibitor offerings to mitigate this type of mechanism. Traditional methods used to mitigate ACSCC include the use of post-weld treatments or costly metallurgy upgrades. With a limited number of examples highlighting the use of chemical abatement of such a corrosion mechanism, the present study describes the use of inhibiting compositions to mitigate stress corrosion cracking (SCC) in refinery processes, particularly due to environments high in carbonate (CO32-) concentration. Herein, an optimized blend is shown to protect the metal surface against carbonate SCC and other corrosion mechanisms.
Organic corrosion inhibitors (CI) have widespread use in the crude oil refining industry for corrosion protection and mitigation.1 An effective corrosion inhibitor is a chemical substance that is applied in low concentration into a stream which suppresses or mitigates a corrosion mechanism.,2,3,4 Inhibitors can be classified into two classes: adsorption or film-forming with organic inhibitors falling under the adsorption class. In this type of inhibitor a self-assembled structure is formed, where an array of hydrocarbon tails extend away from the metal surface and the polar groups (e.g., N in amines) chemisorb onto the metal surface.2 Over the years, certain classes of inhibitors have been established as industry standards to confront specific corrosion mechanisms encountered throughout the refinery process. Examples include, filming and neutralizing amines used in crude units to combat aqueous corrosion; polysulfides used in FCCU to combat hydrogen blistering, cracking and embrittlement; P-based chemistries to combat naphthenic acid corrosion.5