Impact of S-H₂S-RSH corrosion on equipment

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S-H₂S-RSH corrosion is a typical type of high-temperature active sulfur corrosion that occurs in oil refining operations. Its impact on equipment manifests in the following ways: uniform thinning of the equipment’s structure. As this is a chemical form of corrosion, it causes the metal walls of the equipment to thin out uniformly. The bottom sections of coking distillation columns are most severely affected, followed by those of distillation and vacuum distillation columns and catalytic distillation columns. Prolonged exposure to this corrosion directly reduces the equipment’s capacity to withstand pressure. Local erosion corrosion intensifies. In areas where the flow velocity changes abruptly, such as elbows, tees, and pump casings, the protective FeS passivation film is easily washed away by the medium, leading to localized thinning in the form of sharp edges, and even local corrosion-induced perforations, which significantly reduces the service life of the equipment. It induces the risk of secondary failures. Under wet operating conditions, this corrosion mechanism is accompanied by hydrogen penetration, which leads to sulfide stress cracking (SSC). This results in sudden failures of the equipment without any obvious warning signs. It can also damage the original sealing structure of the equipment, thereby causing safety hazards such as fluid leakage. Disruption of production operations: The sulfur compound impurities resulting from corrosion can mix into the medium, potentially causing instability or tripping in subsequent process equipment such as electro-dehydration units, and even leading to the breakdown of the plates, thereby affecting the smooth operation of the entire installation.