VAPOR PHASE CORROSION INHIBITORS (New formula for outservice indust equipments)

Corrosion remains a critical challenge in oil, gas, and petrochemical operations, particularly for equipment stored or operated under humid and aggressive environments. Vapor Phase Corrosion Inhibitors (VpCIs) offer a versatile solution by releasing protective vapors that adsorb onto metal surfaces, forming a molecular barrier against moisture and oxygen. This paper reviews the chemistry, mechanisms, and applications of VpCIs, highlighting traditional compounds such as nitrites, benzoates, molybdates, and azoles, alongside emerging eco‑friendly alternatives including biopolymers, polyethylene glycol, and ionic liquids. Several conceptual formulations are proposed, incorporating mineral oils and carrier materials such as films, papers, and gels, with attention to the influence of oil type (paraffinic, naphthenic, aromatic) on performance. Historical patents and industrial case studies are discussed to illustrate the evolution from early amine‑salt inhibitors to modern sustainable systems. The study emphasizes that optimal VpCI selection depends on metal type, environment, and protection duration, underscoring the need for experimental validation and expert consultation