(57l) Philadelphia Energy Solutions (PES) Refinery Fire and Explosions

This presentation provides a comprehensive analysis of the critical incident that occurred at the Philadelphia Energy Solutions (PES) hydrofluoric acid (HF) alkylation unit in June 2019, emphasizing the importance of safety in the management of hazardous materials. The incident involved a rupture of a steel elbow pipe, leading to a catastrophic chain of events, including a large vapor cloud release and subsequent fire, followed by a series of explosions. The investigations revealed that several factors contributed to this incident. Notably, a lack of inspection requirements for carbon steel piping in HF corrosion zones, along with equipment specification issues. Additionally, the limitations of certain "active" safeguards were highlighted, and it was shown how they can be compromised in fire and explosion scenarios.

The presentation also outlines five key safety issues identified in the PES alkylation unit incident, including concerns related to mechanical integrity, equipment verification, emergency isolation, safeguard reliability, and the application of inherently safer design strategies. To address these issues and enhance safety in HF alkylation units across the industry, the Chemical Safety Board (CSB) put forth a series of recommendation. These recommendations include developing an EPA program that prioritizes inspections of HF alkylation units and revising the EPA Risk Management Plan (RMP) to require Safer Technology and Alternative Analysis (STTA) for both new and existing HF alkylation units. Furthermore, the CSB urges a revision of the 5th edition of API RP 751 to bolster safeguard protection from fire and explosion hazards, with the addition of including the installation of emergency isolation valves. Finally, there is a call for ASTM International to revise ASTM A234 and incorporate supplementary requirements for piping used in HF service.

There is also an emphasis on the critical need for the proactive safety measures, inspection protocols, and the adaptation of inherently safer technologies in the handling of HF. By drawing lessons from this incident and embracing these recommendations, it’s possible to work towards a safer and more sustainable future in the production of hydrocarbon products.