Research On Pool Fire Spread Process Of Large-Scale Tanks In Refined Oil Depot Based On Thermal Response

In recent years,with the in-depth transformation of the energy industry,the growth rate of refined oil consumption has also been slowing down.The rapid increasing number of the oil depots and the expansion of refined oil depots has become one of the important measures to suppress the surplus of refined oil.Therefore,large oil reserve facilities have also become one of the important means for effectively and quickly reducing the cost of oil reserves.With the development of urbanization,refined oil depots,as a gathering place for hazardous chemicals,face a more complex social environment than ever before.However,if a fire accident occurs in a tank in the tank area,it can easily cause secondary accidents in surrounding tanks,which may expand the scope of damage,and ultimately cause huge loss of life and property.The spread of fire accidents in the tank area is mostly caused by the heat radiation of the flame from the accident tank.The establishment of a pool fire accident model for a single tank and the study of the thermal response behavior of the tank surrounded by a fire environment can provide a theoretical basis for the prevention of fire accidents and the control of pool fire propagation in tank farms.For this reason,this article has studied from the following aspects.In this paper,the accident process of fire and explosion accidents in oil tanks at home and abroad was carefully clarified to find out the possible path of fire propagation in the tank farms,and take it as the basis for follow-up research work.A full-surface pool fire was selected as the initial events of the entire spread process to carry out the whole study.Based on the previous research results,this paper uses Fluent software to establish a full-surface pool fire accident model for 50,000 m3 gasoline storage tanks under windy and windless conditions.Corresponding parameters for the consequences of fire accidents(For example,the flame length,dip angle,and heat radiation distribution,etc.)were analyzed and calculated.Compare the simulation results with previous calculations results of the predecessors to verify the reliability of the model.In addition,the influence of wind speed on the consequences of the accident,especially the distribution of heat radiation,was also analyzed.It was found that as the wind speed increases,the strong radiation area generated by pool fire of the accident tank gradually changed from the upper space of the oil pool to the leeward direction of the tank.However,the intensity of heat radiation received by the storage tank located in the leeward direction of the accidental canister tends to increase first and then decrease with the increase of wind speed.At a wind speed of 7 m/s,the target tank receives the highest heat radiation intensity.Based on the flame heat radiation distribution of the accident tank under different working conditions,the thermal response process of the adjacent storage tank under the fire environment was studied by numerical simulation.According to whether the vent valve is successfully opened,the entire thermal response process is divided into two steps for simulation analysis.For the pressure response process in the target tank,the failure criterion of the target tank under fire conditions is adopted as the failure criterion of the float disk strength,Faupel blasting pressure and the critical pressure based on the fourth-strength theoretical calculation.And the time when the fire is propagated at different ambient wind speeds was calculated and analyzed.The results show that the target tank may be detonated about 11 min to 15 min after the initial pool fire accident.The process of spitting oil vapor diffusion from the target tank after the opening of the vent valve and the pressure response process in the target tank when the opening procedure of the vent valve failed were simulated to obtain the time when the pool fire may spread under different ambient wind speeds.The point at which the release gas in the explosion limit concentration range spreads near the initial accident tank is defined as the pool fire propagation time under the contaminated path.The results show that the impact of environmental wind speed on the spread time under this path is very small.