Residual Strength Evaluation of First-Stage Absorber With Weld Considering Corrosion and Thermal Stress

Abstract

The first-stage absorber, which is often used to purify crude oil or highly acidic natural gas, is the core equipment of petrochemical enterprises. Uniaxial strength is checked considering axial stress, hoop stress, and radial stress which is the main design idea of high-pressure vessel. However, absorber integrity issues, due to corrosion, thermal stress, and residual stress caused by welds, can cause absorber deformation, strength degradation, and even explosion. In this paper, mathematical models for absorber strength degradation, due to corrosion and thermal stress, are established. Another finite element model by element activation is established to evaluate the residual stress caused by the welding process. According to the parametric study, the effects of various parameters on residual strength of damaged absorber are studied. Strength check is carried out based on Lame thick-walled solution, and von Mises yield a criterion for the absorber according to the stress distribution of the absorber considering corrosion, thermal stress, and residual stress under tri-axial stress. Finally, accuracy of the mathematical model and the element model, of the effect of corrosion, thermal stress, and residual stress on residual strength, is verified according to actual service environment of the absorber. The research results presented in this paper can offer a technological basis and theoretical foundation for residual strength evaluation and absorber design of the first-stage principal absorber with weld considering corrosion and thermal stress in a sour environment.