Quantitative Risk Analysis Of Fire And Explosion On Topside Of FPSO

Hydrocarbon fires and explosions have always been one of the main risks of offshore installations. As an offshore oil factory, FPSO plays a role in production, storage, offloading,sewage treatment and power supply. However,topside of FPSO often has a compact arrangement and unventilated layout, which may easily result in hazardous fires and explosions in case of oil and gas leakage. So it is necessary to conduct researches on risk assessment for FPSO subjected to hydrocarbon fire and explosion. Based on the MIIT project"FPSO Failure Database and Risk Assessment System Software Development", this paper takes an FPSO serving in the South Sea for example,and carries out work on quantitative risk analysis of hydrocarbon fires and explosions, which can provide theoretical foundation and technical support for risk control of FPSO.In this paper, extensive research about latest theories and progresses has been developed on the fire and explosion risk assessment of offshore platforms. Firstly, considering the equipment components and its operating principle of FPSO topside,facilities which may lead to fire and explosion due to gas leakage are summarized. With the accomplishment of FMEA analysis and RPN calculation, an initial recognition on the risk standard of each facility is achieved. Depending on different ignition time, consequences resulted from gas leakage may be divided into four conditions: jet fire, flash fire, VCE and no ignition. Taking relevant database into account, we may apply Event Tree Analysis to calculate frequency of different consequences. Based on CFD, simulation on leak and diffusion behavior of natural gas in different wind direction, speed, and hole diameter of leakage is performed. Through a comparative analysis to identify the most dangerous leak condition, the influence of fire and explosion acting on the hull and staff and the dangerous zones of explosion overpressure,flame temperature and heat radiation flux can be got. Finally, calculate the value of IRPA and PLL,assess whether risk standard can be accepted by ALARP risk criteria,complete risk assessment and propose reasonable risk-reduction measures.