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Taking into account the background and characteristics of HCN-H₂S-H₂O corrosion discussed earlier, the most common locations for this type of corrosion are found in the low-temperature, humid areas of petroleum refining and chemical processing units. The specific locations are as follows: 1. Catalytic cracking absorption and stabilization systems – This is the most typical area where such corrosion occurs, including the columns and trays of distillation towers, absorption towers, desorption towers, and stabilization towers. The temperature in these areas ranges from 40 to 50°C, and they are rich in H₂S, HCN, and free water, creating ideal conditions for corrosion to occur. II. Top condensation and cooling system: This includes the condensers and reflux tanks at the top of the catalytic cracking distillation column, as well as the condensers, reflux tanks, and top distillate pipelines of the regeneration towers in some oil refineries’ dry gas desulfurization units. The phase change between gas and liquid leads to the continuous concentration of corrosive substances, thereby accelerating the corrosion process. III. Supporting mechanical equipment and pipelines: This type of corrosion also often occurs in gas-rich transmission pipelines, as well as on the impellers and pump casings of machinery pumps, and at pipeline elbows. Vortexes generated by the fluid can damage the protective layer on the metal surface, thereby exacerbating the corrosion damage.