Recommended materials for pipelines in catalytic cracking units

The material selection for pipelines in catalytic cracking units is primarily determined by temperature and corrosion conditions: in areas such as the riser pipes, reaction gas/oil pipes, and pipes for raw/regenerated catalysts, the casing is usually made of carbon steel with thermal-insulating and wear-resistant linings; it is the lining that provides protection against wear and insulation. Among them, the high-temperature sections (hot walls) of the reaction oil and gas pipelines are made of 15CrMo, which has good heat resistance. For the bellows expansion joints in catalyst pipelines, FN2, B315, or Incoloy800 are recommended, as these materials are resistant to high temperatures and corrosion. The cold wall section of the flue gas pipeline is also made of carbon steel with a lining; for the hot wall section, the material used depends on the temperature: 0Cr18Ni9 (304 stainless steel) is used when the temperature does not exceed 650°C, while 0Cr17Ni12Mo2 (316 stainless steel) is used at temperatures above 650°C, as it can withstand higher temperatures. The expansion joint should also be selected as FN2, B315, or Incoloy800. In short, carbon steel is generally used with an inner lining; for areas exposed to high temperatures, heat-resistant steel is chosen depending on the specific temperature, while expansion joints are made from high-performance materials such as nickel-based alloys. .