Analysis of tube bending deformation in petrochemical heater furnace tubes

Abstract

Abstract Serious bending deformation of the tubes was found in the tubular furnace at a petrochemical company. In order to find out its specific reason, Thickness measurement and metallographic analysis were conducted on the problematic part of the furnace tube. Stress analysis by using CAESAR was carried out, in which the working conditions were considered. The results show that the microstructure of the furnace tubes was not abnormal, and there is no overheating, creeping and deterioration damage was existed during operation. Stress analysis show that the primary and secondary stress values of each node were less than the allowable stress for furnace tubes under current condition. However, the secondary stress will exceed the allowable stress when the furnace tube is bended up to 400 mm. Therefore, in order to avoid the replacement of furnace tube and the unnecessary economic loss, the tubes could be used safely under closely monitored after structural rectification.