Quantitative Risk Assessment of Hydrotreated Vegetable Oil at an Oil and Gas Company

Abstract

Introduction: An oil and gas refinery processes flammable liquids so it is prone to various hazards, such as leaks that may lead to pool fires if a heat source is present. A quantitative risk assessment (QRA) was conducted to identify risk, evaluate potential consequences, and implement mitigation measures. Methods: The Hazard Operability (HAZOP) study determined the hazardous spots, and the probability of each equipment failure was determined using fault tree analysis (FTA). Event Tree Analysis (ETA) calculated the probability of every possible consequence caused by leaks. Individual risk per annum and potential loss of life were used to measure the risk level of the system. Results: Based on HAZOP, every operating equipment can potentially cause a pool fire. In FTA, scenarios were developed based on different leakage hole sizes, ranging from 1-3 mm, 3-10 mm, 10-50 mm, 150 mm, and >150 mm. The results indicated that leakage could occur across all operating equipment. Similarly, the ETA applied the same bore size scenarios. Pool fire modeling scenarios resulted in three heat flux zones: the red zone (10 kW/m²), the orange zone (5 kW/m²), and the yellow zone (2 kW/m²). Smaller leak holes resulted in a higher probability but a smaller pool fire radius. The initial risk of the export facility was unacceptable. Therefore, two mitigation scenarios were proposed to minimize the risks: adding safeguards and reducing worker hours. Conclusion: The final results showed that for every piece of equipment, the overall risk of the export facility became acceptable after mitigation.