Corrosion characteristics of hydrogenation refining units

The common corrosion problems in hydrorefining units include sulfide stress corrosion, hydrogen embrittlement, high-temperature sulfurization corrosion, and ammoniation corrosion. In light of these corrosion characteristics, the material selection and preventive measures for various equipment are as follows: 1. **Reactor**: Due to the high temperatures inside the reactor, along with the presence of corrosive gases such as H2S and NH3, high-temperature sulfidation corrosion and ammoniation corrosion can occur easily. When selecting materials, alloy materials with high corrosion resistance are generally used, such as 2.25Cr-1Mo steel. At the same time, coating the inner wall with a corrosion-resistant layer is also an effective preventive measure. 2. **Heat exchangers**: Heat exchangers are prone to sulfide stress corrosion under high-temperature operating conditions. Using materials with better corrosion resistance, such as nickel-based alloys (e.g., alloy 600) or stainless steels with a high molybdenum content (e.g., 316L), can improve their corrosion resistance. 3. **Pipelines**: Corrosion in pipelines is mainly caused by corrosive substances such as sulfides and ammonia present in the medium being transported. Materials resistant to high temperatures and sulfurization corrosion can be selected, such as 5Cr-0.5Mo steel. For the low-temperature section, low-carbon austenitic stainless steels can be used. 4. **Pressure vessels**: Attention must also be paid to issues of sulfide stress corrosion and hydrogen embrittlement; modified materials containing rare earth elements or other strengthening elements can be used to improve corrosion resistance and toughness. 5. **Activated carbon filters** and **dust collectors**: Since they handle sulfur- and nitrogen-containing impurities that can cause corrosion, deposition, and blockages, equipment lined with plastic or rubber is suitable to enhance chemical resistance. Overall, the corrosion protection of hydrofining units relies primarily on proper material selection and good operation and maintenance practices. Regular inspection and maintenance to ensure the purity and dryness of the media in the system are also important measures for preventing corrosion. .