Selection of tube material for high-temperature shell and tube heat exchangers
Thread Content
A high-temperature shell-and-tube heat exchanger is installed in a certain incineration unit for waste heat recovery; it preheats the exhaust gas entering the incinerator (at 150°C) using the high-temperature exhaust gas (at 750°C). The high-temperature exhaust gas flows through the tube side, and 316-grade tubing is used since the gas is non-corrosive. Is this material selection correct? Additionally, is the maximum operating temperature for long-term use the same for 316/316L tubes and sheets? I would appreciate your advice!
The operating temperature for 316 tubing should not exceed 700 degrees; 750°C is too high for burning high-temperature exhaust gases, as the material is not suitable for such conditions.
S31008 can be used at up to 800 degrees, while neither 316 nor 316L can be used at 750 degrees.
SA213T22, T91 are also acceptable. These materials generally take high-temperature corrosion into account.
A flue gas temperature of 700–800 degrees does not indicate the temperature of the tubes； Similar to a boiler furnace where the flame temperature is 1500 degrees, the water wall (containing the steam-water mixture inside) can still be a CS tube.
Temperature is not the main issue, as the temperature of the metal walls will not be very high; the main problem is corrosion caused by the exhaust gases.
Temperature is not the main issue, as the temperature of the metal walls will not be very high; the main problem is corrosion caused by the exhaust gases.