(171c) An Integrated Prediction Model for H2S/CO2 Corrosion in the Pipe of Refinery

The Use of Finite Element Method (FEM) in Modeling Effect of CO₂/H₂S Corrosion

Lihan Zeng, Yan-Ru Lin and M. Sam Mannan

Mary Kay O'Connor Process Safety Center

Artie McFerrin Department of Chemical Engineering

Texas A&M University

College Station, Texas 77843-3122, USA

+1(713) 582-5653, lihan_zeng@tamu.edu

Abstract: Corrosion of equipment is one of the most important factors that results in the serious process safety incidents. Though various types of equipment are subject to corrosion issues to different extent depending on the process conditions, the pipeline and the pipeline network connecting units and equipment are relatively more vulnerable to corrosion. The vulnerability of pipeline to corrosion is due to the internal process conditions. Among the factors contributing to the internal corrosion, substance creating corrosive conditions in the pipeline, such as CO₂ and H₂S, is the most common factor, followed by flow condition of the processes (low, high or turbulent). Different oil companies and research institutions have developed models to predict CO₂/H₂S corrosion in carbon steel pipeline, which works well for the worst-case scenario, but varies widely when more complex effects are considered. In this research, a mechanistic CO₂/H₂S corrosion model was developed that integrates the effect of most important variables. The model investigated kinetics of electrochemical reaction involving corrosive substances, scaling & protective effects, and determined the flow pattern and its effect on the mass transport of corrosion-related chemicals. The software platforms based on finite element method were used to simulate the transport phenomena, which were validated by published experimental and field data.

Keywords

corrosion, pipeline, CO₂, H₂S, flow patterns, finite element method