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The identification and analysis of risks in Hydrogen unit of refinery using HAZOP and LOPA techniques

Akram Delavar, Mahnaz Mirza Ebrahim Tehrani, Seyed Shamseddin Alizadeh


Process industries have always been exposed to fire, explosion and release of chemical materials. To identify and evaluate risk in process industries including oil and gas, there are various methods in which hazard and operability study (HAZOP) is one of the most common methods. To do this, at first all organizational duties and unit activities are identified. Then, the study technique of operation and risk is used as an effective and sys thematic method to identify risk and operating problems and the relevant effects. The identified activities in risk assessment are applied. The results of evaluation of identified risks showed that 6 cases had hazard higher than 15 and it is not acceptable. In terms of risk intensity, the highest frequency of unacceptable risks (4 cases) is observed in “reformer heating chamber”.  The analysis of consequence of hazards showed that for 6 hazardous points, independent layers of protection can reduce risk as 100% to target factor (10-5) and safety integrity level is fulfilled completely.


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