Study On The Explosion Suppression Characteristics Of The Waste Heat Recovery In The Middle Temperature Zone Of The Converter Gas

Converter gas is an important by-product in the process of converter steelmaking,and its temperature is up to 1400 to 1600?,which contains a lot of sensible heat.Converter gas recovery can effectively reduce energy consumption of iron and steel industry,and the two main methods of recovering converter gas are dry gas recovery technique(LT method)and wet gas recovery technique(OG method),and the common disadvantage of these two methods is that the waste heat in the temperature section of the converter gas is not recycled due to the flammable and explosive characteristics of the converter gas.Therefore,it is of great significance to study the explosion suppression characteristics of the waste heat recovery process in the middle temperature section of the converter gas.At present,the inert gas explosion suppression method is widely used in the industry because of its advantages of safety,environmental protection and so on.Heat recovery is usually carried out in gas pipeline,this paper is based on the theory of the laminar flow and turbulence flame development pipeline,the premixed gas of converter gas/air/inert gases(N2,CO2 and H2O)is the research object,the method of numerical simulation is used to research the explosion suppression characteristics of the converter gas on the pipe in the gas heat recovery process.A one-dimensional steady state laminar premixed combustion flame model was established,and the CHEMKIN software was used to simulate the combustion characteristics of the converter gas laminar flow.The reaction regularity of converter gas laminar flame propagation velocity of different concentrations(N2,CO2 and H2O)and different initial conditions respectively and,the sensitivity analysis of key elements,the key changes of free radicals and reactions path analysis were studied,.The results show that the laminar flame propagation velocity of converter gas increases with the increasing of initial temperature,and decreases with the increasing of initial pressure,increases with the equivalence ratio increasing and then decreases with the equivalence ratio increasing;with the increase of the amount of N2 dilution,the concentration of the key radicals of converter gas in laminar flames(H,OH,O,HO2)gradually decreases,the consumption path of H free radical changes greatly,inhibition of CO combustion,laminar flame speed decreases gradually;along with the increase of the amount of CO2 dilution,the concentration of key free radicals(H,OH,O,HO2)in the laminar flame of converter gas is greatly reduced,the consumption paths of CO,H2 and H radicals have great changes,the velocity of laminar flame propagation is gradually reduced,the amount of H2O dilution is 10%,the concentration of key free radicals H OH in the laminar flame of converter gas increases,the change of the reaction path promotes the combustion of CO,the velocity of laminar flame propagation increases,the amount of H2O dilution increases to more than 30%,the change of the reaction path of H and HO2 free radical leads to the decrease of OH free radical concentration in the flame and the decrease of laminar flame propagation speed.Based on the characteristics of laminar flow combustion,a numerical model for turbulent explosion suppression in converter gas in the pipeline is established.The FLUENT software is used for numerical simulation of the explosion characteristics in the pipeline of converter gas,researching the converter gas explosion characteristics and the explosion characteristics of the dilution of different inert gas pipeline(N2,CO2 and H2O),comparing three kinds of inert gas explosion suppression effect analysis,changing characteristic parameters with different initial conditions.The results show that if the pipeline converter gas/air premixed gas was ignited,the flame propagation process is very good reproduction of the classic "tulip" flame propagation process;flame propagation speed,temperature and pressure of the inert gases(N2,H2O,CO2)dilution in the pipeline of converter gas were decreased,the same amount of the gas to dilute to inhibition explosion is CO2,followed by H2O,N2 is the worst;to inhibit the converter gas explosion,the needed amount of CO2 increases with the increasing of initial temperature,decreases with increasing of the initial pressure,first increases and then decreases with the increasing of equivalence ratio,in the vicinity of the chemical equivalent ratio 1.25,the maximum amount of heat is released and the combustion is the most sufficient,and more CO2 is needed to suppress the converter gas explosion.