Risk Analysis Of Gas Jet Fire And Vapor Cloud Explosion On FPSO

Marine oil-gas production devices face a variety of risks in the process of operation,as one of the main risks,gas jet fire and vapor cloud explosion(VCE)occupies a high proportion which can be caused by combustible gas leakage.If the gas is ignited immediately,gas jet fire will form,otherwise the VCE may occur.Floating Production Storage and Offloading(FPSO)is a type of floating production system with the function of collecting,producting,storing and transporting crude oil.However,a compact layout and unventilated arrangement regularly exists on FPSO topside,which has larger probability to trigger gas jet fire and VCE due to combustible gas leakage.This paper takes an FPSO as a research object,on the basic of quantitative risk analysis technique,carries out work on gas jet fire and VCE on its topsise,which can provide guidance for fire and explosion’s risk manage.On the basic of gas jet fire and VCE’s character,this paper conducts risk assessment to their consequences on FPSO topside.Firstly,according to the specific layout of FPSO topside,choose the high-risk devices which could lead to fire and VCE due to gas leakage.Then,Failure Model and Effect Analysis(FMEA)method is used to calculate Risk Priority Number(RPN)of the related devices under gas leakage failure mode,and identify primary separator and gas washing pry as simulation objects to fire and explosion repectively by sorting the RPN.Then,based on Event Tree Analysis method(ETA)and refer to authoritative published statistics,we can calculate the related devices’ probability of leading a fire or explosion.Meanwhile,based on CFD method,numerical calculation on gas jet fire of primary separator and its auxiliary pipeline in different diameter of leakage hole and wind speed are performed,and flame temperature and thermal radiation are analyzed to study the fire’harm to workers as well to devices.Then numerical calculation on gas diffusion behavior and VCE of gas washing pry are performed,and explosion over-pressure on each device’ surface and the change tendency of over-pressure are achieved.Finally,the values of PLL and IRPA are got based on thermal radiation and explosion over-pressure,and all the risk values are checked by ALARP criterion.Targeted protction measures are also been put forward to based on the trait of gas jet fire and VCE in this paper.