Failure mechanism of sulfur transport jacketed pipeline induced by the combined effects of steam erosion and wet sulfur corrosion

Double-layer jacketed pipelines are crucial for the economical, efficient, and safe transportation of sulfur in natural gas purification plants. However, several plants in the Sichuan and Chongqing regions have faced perforation and leakage issues with their liquid sulfur jacketed pipelines during routine operations, hindering long-term stable operation. Taking a specific purification plant as a case study, a comprehensive failure analysis was conducted on its jacketed pipeline, which had been in operation for less than two years. Techniques such as physical and chemical property analysis, XRD, XPS, SEM, EDS, and metallographic examination were employed. The analysis showed that the pipeline’s chemical composition met the standard requirements, its microstructure was normal, and material quality was satisfactory. Corrosion morphology and product analysis revealed internal-to-external corrosion perforation. Considering the actual operating conditions, it was hypothesized that corrosion and impact stress on the inner and outer walls of the pipeline in the liquid sulfur, sulfur vapor, and water vapor environment led to the formation of a weak zone. Based on these findings, design optimization and process parameter adjustments are recommended to enhance the safe operation and management of such pipelines.