| With the development of offshore oil and gas resources,higher requirements are put forward for the risk analysis of fire and explosion of offshore platforms.The measures to reduce the risk of fire and explosion of offshore platform include three aspects: accident prevention,accident control and impact reduction.In terms of accident prevention,this paper studies the FMEA based safety assessment method for fire and explosion of offshore platform.In terms of accident control,this paper studies the impact law of fire and explosion of offshore platform.In terms of impact reduction,this paper studies the fire water spray system of offshore platform.Firstly,in order to ensure the safety of offshore oil and gas development,the risk assessment of fire and explosion caused by the failure of offshore platform equipment is carried out.Based on Fuzzy TOPSIS,grey correlation degree,fuzzy analytic hierarchy process and variable weight method,an improved FMEA method is proposed.The new method can effectively reduce the subjective error caused by rough evaluation in the traditional FMEA method,reduce the error caused by no direct correlation between the failure mode risk level and the positive and negative grey correlation degree,and give more objective and accurate weight to the risk factors O,S and D.The risk of fire and explosion of a gas field offshore platform in South China Sea is analyzed.Compared with the existing methods,the proposed method is simple in structure and comprehensive in consideration,and has practical engineering significance.Based on the CFD method,a vapor cloud explosion calculation model is established.The closed cube model is used to simulate the complex structure of the offshore platform with tubular obstacles parallel or perpendicular to the bottom,and the influencing factors of the gas fire and explosion of the offshore platform are studied.A series of explosion experiments of foreign merge project are selected to verify the model.The quantitative parameters used to measure the uneven arrangement of obstacles are proposed.According to the typical structure of offshore platform,the influence of different factors on the explosion intensity is analyzed.The results show that the larger the obstruction rate is,the greater the overpressure of the gas cloud explosion will be.The more significant the overpressure effect on the specific direction is the arrangement of the obstacles in the specific direction,the denser the obstacles are arranged in the initial stage of the explosion,the greater the maximum overpressure will be.The larger the volume of the equivalent gas cloud is,the greater the overpressure of the gas cloud explosion will be.At the same time,the paper also gives some suggestions on how to arrange the pipelines along the deck unevenly in the dangerous area of oil and gas leakage of offshore platform,which provides theoretical guidance for the safety prevention and control of vapor cloud explosion of offshore platform.Finally,for the fire-fighting treatment process after the fire and explosion of the offshore platform,the fire-fighting water spray system is studied.The fire-fighting efficiency is evaluated by the maximum overpressure of the explosion,and the factors influencing the fire-fighting efficiency of the fire-fighting water spray system are summarized.The results show that when the droplet diameter is small,the fire and explosion can be restrained.When the droplet diameter is too large,the water spray system may be in a failure state,or even aggravate the fire and explosion.Increasing the flow rate can better inhibit the development of fire and explosion on the whole,but the inhibition effect is not significant due to various factors.Increasing the volume of water spray system can more effectively suppress fire and explosion.The water spray system in the flammable and explosive areas around the setting is more conducive to the improvement of fire efficiency.A simplified offshore platform model of a platform in South China Sea is used to analyze the depressurization of water spray system. |
