CORROSION CONTROL IN HEAT EXCHANGERS OF CRUDE OIL REFINING PLANTS: MECHANISMS, PREVENTION APPROACHES, AND THE CONTRIBUTION OF CORROSION INHIBITORS

Abstract

Heat exchanger units rank among the refinery components most susceptible to corrosion damage, since they operate under a combination of elevated temperatures, thermal differentials, dual-phase streams, and corrosive contaminants present in crude oil. The present study examines the principal corrosion pathways affecting shell-and-tube exchangers as well as air coolers installed in atmospheric-vacuum distillation (AVT) facilities. Among these pathways are high-temperature sulfidic corrosion and hydrogen sulfide attack, hydrochloric acid corrosion within condensation regions, under-deposit corrosion caused by ammonium chloride and ammonium bisulfide, and erosion-corrosion phenomena.

The work further surveys prevention strategies that complement one another: desalting of crude feedstock, neutralization of overhead vapor streams, appropriate material selection, process parameter control, and the dosing of film-forming corrosion inhibitors. Particular emphasis is placed on the nitrogen-based film-forming inhibitor KAFN-2024, which was formulated by the author. Industrial-scale trials demonstrated protection levels of 94.6-95.1% at dosages of 75-100 ppm, thermal stability reaching 200 °C, and satisfactory performance across a pH window of 6.5-9.8. Findings indicate that a combined strategy - wherein a site-specific inhibitor works alongside desalting and neutralization measures - is capable of prolonging heat exchanger service life and lowering reliance on foreign-supplied chemicals.