Material of shell-and-tube methanol synthesis tower
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I’d appreciate it if my friends could help by sharing what types of materials they have used for the cylinder bodies of shell-and-tube methanol reactors (under 5 MPa pressure, with boiling water in the shell side). Have they used 20MnMoNi55 or 13MnNiMoNbR? How are these reactors performing currently? Thank you!
All of them! Tianchen Institute uses 20MnMoNi55 more frequently, while the Second Institute uses 13MnNiMoNbR more often. It’s running well at the moment.
Could someone upstairs let me know which households are currently in use? Thank you!
Chengda Company (formerly the Eighth Chemical Research Institute) has introduced a manufacturing solution for methanol synthesis towers: the shell is made of 16MnR, the tubes are made of 15CrMo, and the tube sheets are clad with Incoloy600 on a 304 base. By using ordinary metal materials, not only are significant costs saved, but the manufacturing time is also reduced.
The methanol towers in large-scale methanol plants utilize foreign technology: water-cooled methanol towers, with a design pressure of 5.1 MPa for the shell side and 9.5 MPa for the tube side； Design temperature: Shell side: 265°C, Tube side: 280°C. The shell material is SA-387 Gr.11 CL2 (UNS K11789); the tube sheet material is SA-336 Gr.F11 CL3 (UNS K11572); and the heat exchange tubes are made of SA-789 (UNS S31500). A catalyst is installed inside the heat exchange tube. The equipment is designed using stress analysis methods, and the inner wall requires polishing. Gas-cooled methanol reactor: design pressure, shell side: 9.5 MPa, tube side: 9.5 MPa ； Design temperature: Shell side: 300°C, Tube side: 270°C. The shell material is SA-387 Gr.11 CL2 (UNS K11789), and the heat exchange tube material is SA-213 TP321 (UNS S32100). A catalyst is filled inside the heat exchange tube. The equipment is designed using stress analysis methods, and the inner wall requires polishing
They mentioned the methanol synthesis tower upstairs; why is stress analysis used in the design of such equipment, when there are no alternating stresses during operation?...
The cylinder of the methanol synthesis tower is also made of two different materials: one type is used for the section with tube sheet reinforcement, and another type is used for the section without such reinforcement; these materials are distinct from each other.
It adopts the methanol synthesis tower design of Nanjing Haowan. The nominal diameter is DN3400, with a design pressure of 4.0 MPa for the shell side and 8.0 MPa for the tube side； Design temperature: Shell side: 265°C, Tube side: 280°C. The shell material is 16MR; the tube sheet material is 20MnMo; the tube box material is 15CrMoR. Catalysts are installed inside the heat exchange tubes. Due to the adoption of a new structure and the replacement of the heat exchange tube material from the commonly used duplex steel to ordinary 304 steel, the cost of the equipment has **decreased**. The long-standing problem of weld cracks in the shell caused by differences in the expansion coefficients of the materials in the tube side and shell side has also been effectively resolved. I was responsible for the detailed design of this equipment. It has been in operation for several months now, and all performance parameters meet the required standards.
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How do they avoid differences in linear expansion coefficients through structural design?
I don’t have your contact information, but I’d like to discuss with you the issue of material selection for reactors.