The Research On Diffusion Regularity And Hazardous Concentration Area Of Lng Leakage

Liquefied natural gas which is a clean,efficient,economical and green energy plays a very important role in industry,business,residents,cooling,heating and car’s fuel.With the increasing trade projects of LNG,a variety of LNG stations start to put into construction.But in recent years the frequent natural disasters,rampant terrorism and human wrong operation can lead to LNG leakage accidents.Because of the basic characteristics of liquefied natural gas,the accidents of LNG tank leakage in LNG station may cause serious damage to life and property.Therefore,this paper focuses on the research of the regulation of LNG leakage diffusion and the range of hazardous concentration.This research will offer a significant reference for leakage accident prevention,drafting emergency measures,emergency alienation area designing and post evaluation of damage degree.Since the early 1970 s,many scholars have been using field experiment,wind tunnel experiment or numerical simulation to study the leakage diffusion regulation of LNG.This paper will use the numerical simulation as is superior to others to simulate and analyze the law of LNG leakage diffusion.The study analyses the exit mass flow rate,the exit spouting velocity and leakage duration under three types of LNG tank leakage that is liquid phase,gaseous phase and gas-liquid two-phase.Moreover,calculating and analyzing the engineering example of liquid phase leakage of liquefied natural gas tank.To conclude,the liquid leakage rate and exit velocity in tank gradually decline with the increase of leakage time,increase as the gas absolute pressure in tank increasing,increase with the increase of liquid level height.The quality rate of liquid leakage increases when the area of the leakage hole becomes lager.On the contrary,the exit spouting leakage velocity decreases with the leak area gradually increasing.Combining the plate model and gaussian model to establish a LNG continuous leakage diffusion model to simulate the LNG leakage diffusion under different influent factors.Dividing the hazardous concentration area of LNG leakage gas and calculating the areas both explosive combustion concentration and hazardous concentration for human body.Conclusion shows that the stronger the leakage intensity of source,the shorter the downwind distance,the wider the width,and the lager the area of the hazardous concentration region.Second,the higher the source of the leakage,the shorter the downwind distance,the wider the width,and the lager the area of the hazardous concentration region,but the overall change is little.Third,the higher the atmospheric stability,the farther the downwind distance,the wider the width,and the lager the area of the hazardous concentration region.These results will benefit the prevention of LNG leakage accidents and the draft of emergence measures a lot under the research data.