Explosion-Combustion Consequence Analysis for Catastrophic Failure of the D-۳۰۰۱ Ethylene Oxide Storage Tank in the MEG Unit Using PHAST (UDM & Multi-Energy): Overpressure, Flash Fire, and Pool-Fire Hazards

This study assesses the consequences of catastrophic rupture of the EO storage tank D-۳۰۰۱ in the MEG unit at Pars Glycol, using real DCS data and PHAST ۷.۱۱. Heavy-gas dispersion was modeled with UDM and vapor cloud explosion with the zmulti-Energy method. Four rupture scenarios were evaluated: S۱ (۱۰۰% fill, pure EO), S۲ (۱۰۰% fill, ۴۲% EO), S۳ (۵۰% fill, ۴۲% EO), and S۴ (۲۴.۵% fill, ۴۲% EO). PHAST results show that the ۰.۳-bar overpressure radius decreases from ۲۵۰ m in S۱ to ۱۸۰, ۱۱۰, and ۶۵ m in S۲-S۴, while the ۳۷.۵ kW/m² thermal radius contracts from ۵۰ m to ۳۵, ۲۰, and ۱۵ m. Scaled analysis of scenario visuals confirmed parallel reductions in cloud footprint, flash fire envelope, and maximum concentration footprint, with overall shrinkage of ~۷۰% from $۱ to S۴. The reduction trend is driven by lower EO inventory, reduced partial pressure, and increased rainout, which together limit the flammable cloud's size and persistence. Maintaining a ۲۴-۳۰% fill level with a ۴۲/۵۸ EO-water mixture significantly reduces both blast and thermal hazard zones, offering a practical and safe operational strategy.

کلیدواژه ها:

Ethylene Oxide (EO) ، Vapor Cloud Explosion (VCE) ، Flash Fire ، Pool Fire ، Overpressure ، PHAST (UDM & Multi-Energy) ، Safety and Fire Management