Process safety management lessons learned from a fire accident caused by the reverse flow of high‐pressure gas in a residual desulfurization process in Taiwan

Abstract

AbstractIn 2020, a fire and explosion accident occurred in Taiwan because of the reverse flow of high‐pressure recycle gas. This accident resulted in three minor injuries and caused the Taiwanese government to instruct the top three chemical groups in Taiwan to conduct procedural hazard and operability (HAZOP) studies in addition to normal HAZOP studies. The cause analysis based on the accident timeline and cause factor chart indicated that improper control of the protection logic bypass and the lack of four process safety management (PSM) elements, namely mechanical integrity, process safety information (PSI), operating procedures, and process hazard analysis (PHA), were the root causes of the aforementioned accident. The deficiencies leading to accidents are related to planning problems in PSM promotion but unrelated to the implementation of PSM programs. Maintenance processes should be evaluated and developed according to PHA results or equipment structure to guarantee equipment integrity. The incompatibility of process chemicals with pipeline materials should be considered; then, the construction materials mentioned in PSI should be extended to those of pipelines, not just equipment. In addition to the hazards of normal operations, those of non‐routine operations should be identified to ensure the completeness of the PSM program. Protection logic bypass should be appropriately controlled, and a complete safety evaluation must be conducted before resetting the initiated protection logic. A majority of the deficiencies identified in this study exist in most Taiwanese chemical companies, including the leading ones performing PSM. The lessons learned from the aforementioned accident provide advance information that can be used to develop an improved PSM system.