What material is used for high-pressure air cooling in hydrogenation? What is the extreme operating temperature?

Does the material need to be chosen based on the processing conditions?

Currently, the criterion for selecting materials for air-cooler tubes in engineering design is based on the value of Kp. Kp＝× Where: Kp — corrosion coefficient of the logistics ； — Concentration of H2S in the dry hydrocarbon stream of the reaction effluent, mol% ； — Concentration of NH3 in the dry hydrocarbon stream of the reaction effluent, mol%. When Kp＜0.1, carbon steel tube bundles can be used for high-pressure air coolers, with the maximum flow velocity controlled at 9.3 m/s. Kp=0.1~0.5; the corrosion situation of carbon steel high-pressure air coolers is relatively complex, and carbon steel or high-alloy steel should be selected according to specific conditions. When the material is carbon steel, the flow velocity range is 4.6~6.09 m/s. When Kp＞0.5, corrosion can occur in carbon steel high-pressure air coolers at any flow rate; therefore, high-alloy steels such as 3RE60, Monel, Incoloy 800, and Incoloy 825 should be used. When it comes to high-pressure air cooling, one shouldn’t focus only on the maximum operating temperature. Generally, the temperature after cooling should be between 45-55°C. If this temperature exceeds 60°C, it may result in poor separation of oil and water in the cooled mixture, leading to a low level of the interface – or even no such interface at all