Analysis of protective layers by LOPA method and determining the level of process safety integration (SIL) of Equipment in Imam Khomeini Petrochemical Aromatic Unit

Document Type : Original Article


1 Department of Environmental Sciences, Ahvaz Branch, Islamic Azad University, Ahvaz, Iran.

2 Environmental Technologies Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.

3 Department of Electrical Engineering, Ahvaz Branch, Islamic Azad University, Ahvaz, Iran.



Background: In this industry accidents are generally catastrophic and cause irreparable human, environmental and economic losses. In these industries, there is a wide range of flammable and toxic substances that can affect the health and safety of workers and also have adverse effects on the society. Carrying out numerical risk assessment studies and impact assessment along with the design of protective layers against catastrophic events is part of the requirements of designing process units.
Methods: This research was done in 2019, first the identification of occupational-process and environmental safety hazards is done by Hazop and EFMEA methods. Then the risk is assessed using the LOPA method.
Result: The results showed that a total of 50 safety, health and 37 environmental risks were identified in HAZOP and EFMEA methods in Khomeini Petrochemical Aromatic Unit. There were 17 low-level identified risks, 19 medium-level risks and 14 high-level risks.
Conclusion: The results of this study show that the use of LOPA method to separate analysis of protective layers is more complete than hazard identification methods. The important actions was the blockage of excess gas to the flare and the release of H2S gas. The results of the evaluation of the environmental aspects of the activities of the aromatic unit also showed that the 4 environmental aspects of air pollutant production in the power supply unit, reactor tank waste disposal, condensate tank waste disposal and reactor fire and explosion are at a high level.


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