2400 Longhorn Industrial Drive, New Braunfels, Texas 78130 Ph: (830)629-8080 Fax: (830)629-6899 email: [email protected] Copyright © 2001 Senior Flexonics Pathway. NEWS RELEASE When Toyo En- gineering was re- quested to sup- ply replacement expansion joints for a Kyushu Oil Ltd. FCC, It was clear to everyone that the very best technology would be neces- sary. The cus- tomer had expe- rienced cracking problems on cer- tain high tem- perature FCC expansion joints and was very sensitive about the life span of expansion joints in FCC service. Senior Flexonics Pathway employed the most current technol- ogy available to insure the best performance for Kyushu Oil Ltd. The double gimbal expansion FCC flue gas expansion joint was designed to handle 57 PSIG (4.01 Kg/cm2) at a temperature of 14270F (775 C). The expansion joint was of hot shell design. In order to eliminate problems with cracking of the pipe in service, the pressure thrust restraint rings attached to the hinge arms were designed to be floating structures. This floating ring concept al- lows the pipe to grow radially without being restricted by the cooler rings. In the creep range of operating tem- peratures, this feature is critical to avoid excessive pipe stress. Stainless steel is subject to embrittlement after many years of service in the creep range. This problem is mini- mized by careful control of the ferrites in the deposited metal of pipe welds and by eliminating welds wherever possible. To minimize welds, Senior Flexonics Pathway TOYO ENGINEERING DEMANDS THE BEST FCC EXPANSION JOINT used proprietary pipe expander equipment to create the four transitions required for the double gimbal design. This process eliminated 8 circumferential welds that oth- erwise would be required. Senior Flexonics Pathway also controlled the ferrite level of the weld wire and then solu- tion annealed the pipe to put the pipe into the most sat- isfactory condition for long term use at high tempera- ture. Most Senior Flexonics Pathway customers consider a high nickel alloy like Alloy 625 to be the best expansion joint material for FCC service. However, FCC operating conditions are above the safe operating temperature for most high nickel alloys including Alloy 625. To keep the bellows in the best operating temperature range, Senior Flexonics Pathway internally insulated the bellows. A special type of high nickel alloy called Alloy 625 LCF was used for the bellows. Alloy 625 LCF is marketed exclusively by INCO Alloys. This very fine grain version of Alloy 625 has superior fatigue performance and resis- tance to embrittlement up to 1200OF (648 C), signifi- cantly higher than straight grade Alloy 625. To insure the very best fatigue performance, the bellows were not an- nealed after forming. Each bellows was of ply testable construction. This con- cept involves a two ply bellows in which each ply is de- signed for the full operating conditions. This results in a 100% safety factor on the bellows elements and the ability NR 73 Technology for Kyushu Oil Refinery Ltd.