Introduction: Being aware of the explosion, fire radius, and their damages, has an important role in accident prevention methods. Therefore, the aim of this study was modeling and evaluation of the consequences of propylene oxide spill in a petrochemical company.

Material and Method: The QRA method including seven steps was used in this study. In the present study, in order to examine and modeling of the propagation propylene oxide, first a familiarization with the process information of the unit was done then, a risk assessment was carried out adopting HAZOP technique to identify existing hazards. Consequence analysis in a process unit includes: selecting important scenarios, characterizing scenario, modeling the consequences of scenarios, analyzing the results and determining the percentage of mortality. PHAST software version 6.51 was used for modeling of outcomes and assessment propylene leak.

Result: urves of the firing zones of sudden release of propylene oxide showed that the influence puts are included up to radius of 0.15 meters in the scenario of leakage 5 mm, in scenarios with leaks 25 mm to a radius of 1.1 meters and in scenarios with leakage of 100 mm to a radius of 39 meters. The maximum intensity of flash fire in the initial point Scenario 5 mm was 4.2 kW/m2, in the scenario of radiation leakage was 25 mm at the distance to 5 meters from the fire intensity up to maximum of 9 kW/m2, and also in the scenario with 100 mm flash fire radiation leak at an earlier point fire was 14 kW/m2. The maximum intensity of thermal radiation at the distance to 5 meters up to 16.5 kW/m2, and maximum distance of 80 meters around the reservoir affected. The mortality rate of flash fire has exposed employees, was 50 percent.

Conclusion: Many accidents caused by leakage and explosion were due to corrosion, spoil tanks and equipment, and the majority of such accidents can be prevented by technical inspections and continuous audits.