Quantitative Analysis Of Pool Fire On Topside Of FPSO

Hydrocarbon fire is one of the most dangerous kind of risk types with high frequency in offshore field. Floating production, storage and offloading units (FPSO), as a kind of offshore installation with the abilities of storing crude oil and preliminary process, has higher frequency to assume hazardous fires because of compact arrangement and unventilated layout on its topside model. Owing to FPSO’s work zones are far away from land, it will lead to a more serious consequences if fire occurs. Pool fire could be defined as a kind of fire whose elding is combustible liquid or fusible solid, which is a typical type of fire risk. If crude oil leaks from the facilities of FPSO topside model and be ignited, pool fire occurs, it will lead a disastrous effect to both workers and facilities. This paper takes an FPSO for example, based on quantitative risk analysis method, carry out work on crude oil pool fires on the topside of FPSO through four main steps: hazard identification, consequence assessment, probability calculation and finally risk quantification, which can provide theoretical foundation and technical support for pool fire’s risk manage, control and precaution.This paper is based on pool fire basic theory, and apply risk assessment technology to pool fire analysis on FPSO topside model. Zone FPSO topside model into four process areas according to arrangement and summarize the facilities in different process areas to find out the hazardous facilities which ones could lead to pool fire. Then, based on FMEA method to calculate RPN of hazardous facilities, and select primary separator, flotation unit,second-stage heater and crude oil separator as four target facilities according to hazardous facilities’ RPN and arrangement. Then, based on Event Tree Analysis method(ETA) and combine the probabilities of leakage which are achieved through OREDA database with the probability of igniting a pool to calculate the target facilities’ probability of leading a pool fire.The result shows that second-stage heater has the highest probability to lead a pool fire.Meanwhile, based on CFD, simulation on diffusion behaviors of pool fire in different wind speed and different location of pools are performed to get the pool fires’ harm to surrounding facilities as well to workers. The results shows that the pool fire caused by second-stage heater is most harmful to surrounding facilities, and the pool fire caused by primary separator is most harmful to workers. Last, the value of IRPA and PLL are proofread according to ALARP principle and find out that all the risk result could be accepted by ALARP principle.This paper also proposes relevant measures for pool fire precaution and protection according to the character of pool fire.