Numerical Simulation Study On Explosive Parameters Of Methane And Carbon Dioxide Mixtures

Methane combustion explosion is very common in industrial scenes.In industrial activities,methane-induced combustion explosion is very common,methane combustion explosion accidents are often serious consequences,spread wide,resulting in poor social impact.In the industrial scene,the coexistence of carbon dioxide and methane is common,such as the exploitation of acid gas fields and the process of storage and transportation,coal mined-out areas and mine gas drainage processes.Carbon dioxide is an inert gas,its existence will affect the combustion and combustion performance of methane.To study carbon dioxide and methane mixture combustion and explosion process,can provide guidance for the safety of industrial processes.In this paper,the combustion and explosion characteristics of methane,carbon dioxide and air mixture are studied by numerical simulation of FLACS software.It is divided into simulated explosion of 20 L cylindrical explosive container and simulated natural gas treatment station.During the explosion of the simulated 20 L cylindrical explosive container,the methane concentration is maintained at 10%.The initial parameters(20-170 ?),initial pressure(0.1-2.2MPa),carbon dioxide concentration(0-20%)are changed.This paper mainly studies the explosion temperature,the maximum explosion pressure,the maximum explosion pressure arrival time,and compares with the theoretical calculation value,and analyzes the influence law.The two-dimensional flow field of the combustion process under different initial conditions is compared.The results show that:(1)The initial pressure increases,but the ratio of the maximum explosion pressure to the initial pressure is unchanged;the concentration of carbon dioxide increases and the ratio of the maximum explosion pressure to the initial pressure decreases linearly;the maximum explosion pressure decreases with the increase of the initial temperature,roughly inversely proportional function.(2)The explosion temperature decreases with the increase of the concentration of carbon dioxide.The initial pressure has little effect on the explosion temperature.When the carbon dioxide concentration is more than 10%,the explosion temperature increases with the initial temperature.When the carbon dioxide concentration is less than 10%,the explosion temperature is the same as the initial temperature irrelevant.(3)Carbon dioxide is reduced and the initial temperature increases,resulting in a decrease in the maximum explosion pressure arrival time.In general,the increase in initial pressure will increase the maximum explosion pressure arrival time.(4)The mixture under different conditions of the explosion process is consistent,changes in conditions do not influence the reaction process.Simulation of the actual natural gas treatment station explosion process draw the following conclusions:(1)The size of the vapor cloud impact on overpressure.The concentration of carbon dioxide increases,and the overpressure of vapor cloud decreases.Ignition position on the impact of overpressure complex,need to judge according to the actual situation.(2)Part overpressure damage to personnel is very small,but all the scenes under the explosion temperature are 1900 K or more,need to strengthen the explosion temperature on human injury research.