LIFE ASSESSMENT OF A C-1/2 MO PETROLEUM REFINERY PRESSURE VESSEL OPERATING IN THE CREEP REGIME

摘要

A comprehensive Fitness-for-Service assessment was conducted to evaluate a C-1/2Mo pressure vessel which has operated at temperatures in the creep range for almost 45 years. An initial damage assessment based on elastic stress analysis results indicated that this vessel was approaching its predicted failure life and thus there was little potential for increasing the operating temperature. Creep tests were conducted on samples removed from high stress regions of the vessel according to the MPC Omega Program protocol. The creep test results indicated that the material possesses creep strength superior to average new material and therefore has substantial remaining life. A nonlinear finite element analysis incorporating the MPC Project Omega creep law was performed to assess creep and fatigue damage. The results of this assessment indicated that future operation at increased temperatures was indeed feasible.