New Fina FCC in Port Arthur Uses Senior Flexonics Pathway

Expansion Joints with Unique Designs

The FCC at the Fina Refinery in Port Arthur that was started up in 1991 was one of the only new FCC units built in the United States in the previous decade. The expansion joints furnished through Foster Wheeler New Jersey, were designed to very detailed specifications authored by Zydex Engineering.

The basic UOP specification for the hot shell spent catalyst standpipe expansion joint was modified to include ply testable bellows. With this concept, the bellows are two ply construction. But each ply is designed for the full rated operating pressure and temperature of the media. This allows for 100% redundancy or 100% safety factor in the bellows design. Each of the ply testable bellows were fitted with a red top, an early warning leak detector that is patented by Senior Flexonics Pathway. In the photo of the spent catalyst stand pipe expansion joint, the red top is pointing toward the floor at the far end of the assembly.

The regenerated catalyst expansion joint and catalyst recirculation expansion joint were cold shell construction. The refractory detail of the cold shell lines was unusual in that all transitions from hot shell to cold shell were handled by conic sections that did not slope more than 15 degrees. A typical detail section of the cold shell expansion joints is shown. While this detail ensures minimum stress and warpage due to thermal gradients, the length required to achieve this low slope is not often available.

All local pipe stresses were calculated in accordance with WRC 107 or finite element analysis techniques. The bellows attachment welds (alloy 625 to carbon steel) on the cold shell designs were inlaid with high nickel alloy to eliminate bimetallic attachment welds. Covers were designed to hold pressure in case they were welded closed in service.

To find out more about expansion joints for FCC service or other critical applications, contact Senior Flexonics Pathway.