Hot Wall Expansion Joints for FCC Service
Hot Wall expansion joints usually have some form of abrasion resistant lining, comprised of hex-mesh and castable material or refractory such as Resco AA-22®, a common abrasion resistant material. The lining is designed to withstand the abrasion from the catalyst flowing through the unit in service. The lining requires a thermal dry out after installation.
The lining is not intended to be used as a thermal barrier; therefore the shell temperatures of the expansion joint rise above the allowable temperatures for normal carbon steels. The joint shells are normally manufactured from various Chrome Moly alloys and stainless steels. Due to their trademark conical sections near the bellows area, hot wall expansion joints are easily visible. The oversize bellows allows for a smooth flow across the bellows area using a straight through liner arrangement.