FCCU EXPANSION JOINTS IN COMPACT DESIGN
ASME B31.3 and Axens
For an oil refinery in Russia Belman has supplied in total two FCCU Expansion Joints in compact design – one Spent Catalyst Expansion Joint and one Regenerated Catalyst Expansion Joint.
The client need and specification covered the requirements for the design, fabrication, inspection, and testing of two FCCU Expansion Joints working under highly erosive and low pressure conditions in the FCCU plant of the oil refinery. For both the Spent Catalyst Expansion Joint and the Regenerated Catalyst Expansion Joint the requirements were; the Expansion Joints should absorb both axial, lateral and angular movements simultaneously. They should be equipped with lifting lugs and the spool piece and flanges are to be designed to minimize bending or thermal stresses in the attachment weld. Furthermore, the bellows shall be oversized to get an internal diameter flush with the corresponding pipe after lining installation. Last yet important the Expansion Joint elements shall be protected against movement beyond design amounts by means of limit bolts across bellows or other suitable method, limit bolts or limit stops shall be designed to carry against bellows pressure thrust at Expansion Joint design pressure – while ensuring the design do not exceed the allowed the spring rate and pressure thrust load.
With not only the application setting high demands for the design as well as the short build-in length Belman designed two Expansion Joints exactly as per client needs that also meet the requirements from the client. The Expansion Joints are designed for absorbing the movements and the pantographic gimbals are placed to ensure uniform absorption of the multiplane movements, thereby avoiding premature wear out of the bellows. Furthermore, the Expansion Joints were designed to not exceed the allowed spring rate and pressure thrust load. Bellows were also specially designed with extra safety to avoid unplanned shutdowns.
More security added with 2-ply testable bellows & leak detection
Leak monitoring was also specified amongst the requirements. For that reason, pressure gauge devices are installed at the Expansion Joints to indicate any issues with the bellows during operation. Further, the Expansion Joints are specified with 2 ply testable bellows with redundant ply design. With this construction the single layer would be able to carry the full load in the event of operating alone. In other words, if one of the layers fails, the other ply would be able to secure operational safety of the Expansion Joints until a scheduled shutdown.
AXENS & ASME
The FCCU Expansion Joints are calculated according to ASME B31.3 and Axens standards with the anchor arrangement being designed according to UOP. Belman has vast experience in the design of Expansion Joints according to different standards and design codes. Due to this substantial experience Belman can easily customize the design and production to any required design code and/or standard required by the client and application.