Experimental Study On Superfine Water Spray Containing Surfactant To Suppress Explosion Of Pipes With Different Blocking Rates

Coal is an extremely important energy strategic resource for social development at the moment,and it is also one of the non-renewable energy sources.There are many hidden safety hazards in coal mining.Among them,gas explosions account for a high proportion of coal mine safety accidents.This not only seriously threatens the lives of people,but also brings incalculable losses to coal safety production.In order to prevent these high-risk accidents from happening again,on the basis of previous studies,this paper combined the physical and chemical properties of surfactants,and carried out the explosion of 9.5% methane / air premixed gas by ultrafine water mist modified by surfactants.Research on the characteristics of explosion suppression,and further analyzed the mechanism of the surfactant to suppress the explosion of premixed gas from the elementary level,and provided reference measures for reducing the threat of gas disasters.This article selects anionic surfactant sodium octadecenoate(additive A),nonionic surfactant alkylphenol polyoxyethylene ether(additive B)and zwitterionic surfactant dodecyl dimethyl betaine(additive C))As the fine water mist additive used in the experiment,the research focused on the inhibitory effect of the superfine water mist containing surfactant on the explosion of 9.5% methane-air premixed gas.By changing the mass fraction of the additive and applying the amount of water mist to analyze the premix In the process of gas explosion,the ultra-fine water mist containing surfactant has the ability and difference in delaying the flame propagation front,reducing the average flame propagation speed and weakening the explosion overpressure peak.The addition of surfactant can not only reduce the surface tension of ultra-fine water mist,but also improve the suppression effect of pure water ultra-fine water mist on the premixed gas explosion by reducing the particle size of ultra-fine water mist mist droplets.It can also increase the solubility of methane in the ultra-fine water mist,improve the adsorption capacity of the ultra-fine water mist to methane molecules,and the carboxylic acid group and quaternary amine group in the ultra-fine water mist of the surfactant.Sodium ions and easily broken ether bonds can capture and destroy the active groups in the explosive chain reaction,block the positive feedback mechanism of the explosive reaction,and reduce the intensity of the explosive reaction.Especially under the best explosion suppression conditions(that is,the amount of water mist applied is 22.4m L,the mass fraction is 10%)under the action of additive A superfine water mist,the explosion pressure rises slowly,and the maximum overpressure peak of the premixed explosion is 11.7 k Pa,which is 4.9 k Pa lower than that of the ultra-fine water mist without additives,and the decrease rate reached 29.5%.Under the condition of non-blocking rate,the average flame propagation speed is significantly reduced after the application of ultra-fine surfactant water mist,and the time taken for the flame propagation front to reach the vent port is significantly extended;the average propagation of the ultra-fine surfactant water mist to the flame The speed reduction ratio reached 66.7%(Additive A),55.8%(Additive B)and 61.2%(Additive C),and the retardation of the flame propagation front reached 63.8%(Additive A),46.8%(Additive B)and 51.5%(Additive C),inhibitory effect Additive A> Additive C> Additive B.As the blocking rate increases from 0 to 75%,the peak pressure of the premixed gas explosion gradually increases,from 21.7 k Pa to 66.4 k Pa,and the peak pressure of the premixed gas explosion also gradually advances.When the best explosion suppression Under the condition that the ultra-fine water mist acts on the premixed gas explosion of pipelines with different blocking rates,the average speed of flame propagation and the advancement of the flame propagation front turn around when the blocking rate is 25%.There is a positive correlation when the blocking rate is less than or equal to 25%,and a negative correlation when the blocking rate is greater than 25%.