Optimization Of Oxygen Gun Parameters Of 300t Converter

Oxygen lance is main equipment of oxygen top-blown and top and bottom combined-blown converter steelmaking.The oxygen lance nozzle parameters and reasonable operation mode have a great influence on smelting process,cost,and product quality.There are still existing some problems of selecting parameters of the oxygen lance in large-scale converter steelmaking for different smelting process.Therefore,the choice of oxygen lance parameters has great importance for oxygen top-blown converter.The paper investigated the using situation of the oxygen lance in a certain steel company.The oxygen pipeline pressure loss was tested and the system design was analyzed.In the field,the measured values of flowmeter lower than actual value by more than 9%.Existing the problems such as tapping temperature was low,part of the lime lumpiness was greater than 80 mm,scrap ratio was low,the dephosphorization rate was low in the early stage of the blowing,the slag getting dry and bonding serious in mid blowing,and the molten steel carbon-oxygen equilibrium was higher.All of these influence the effect of blowing.In order to improve the blowing effect,improve the efficiency of oxygen,the original 5 hole oxygen lance nozzle(throat diameter is 48.2mm,Mach number is 2.05,central angle is 15°)was calculated.Adopted the 1:9 converter blowing mechanical model,analyzed the influence of jet flow on the penetration depth of molten pool,impact area,blending time(mixing).The impact depth of the original oxygen lance nozzle was greater,and jet mixing was low,these not good for raising the dephosphorization rate of the early blowing,and reducing the final carbon-oxygen equilibrium,etc.Therefore,optimized the design parameters of oxygen lance nozzle,changed the 5 holes to 6 holes to enhance the capacity of mixing,and designed new nozzle parameters as follows: throat diameter is 41.5mm,Mach number is 2.1,and central angle is 16°.Though the theoretical calculation obtained that,the total area of the throat decreased by 12.4%,the actual use of oxygen pressure increased by 14%,the same lance for molten pool of penetrating lower than 2.4%,the top-blown mixing can increase 2.5%,and the blending time shorten by 0.5%.The cold flow field of two kinds of nozzles was analyzed,and the velocity of jet axis attenuation and the impact area of the molten pool under different operating lance positions were analyzed.The result showed that 6 holes nozzle jet central attenuated faster than the 5 holes nozzle.On the same conditions,the impact area of 6 holes nozzle was increased than the 5 holes nozzle within a certain range of lance positions.The industrial test was researched using the new 6 holes nozzle,and optimized the position of the lance in different stages.The average tapping temperature was increased from 1618? to 1649?,the carbon-oxygen equilibrium was reduced 0.00031%,the consumption of lime was reduced 9.22 kg/t,the steel end phosphorus was reduced 0.00253%,the dephosphorization rate was increased 0.1%,the end slag TFe was reduced 3.77 %,and the service life of oxygen lance nozzle was prolonged to 167 furnace.