Numerical Simulation Sintering Process With Gas Fuel Injection

The energy consumption of sintering process is about 10%of total consumption of iron and steel production process,and ranked second.The heat in the sintering process is mainly supplied by solid fuels,so it has great significance to reducing the fuel cost of sinter cost and also steel production cost.Furthermore,if the gas byproducts of steel production process could be reused in sintering process,solid fuel(coke,coal and other primary energies)can be saved,and the by-products can be utilized effectively.Gas fuel can change the sintering process,and different gases have different properties,the influences to the sintering process will be different.In addition,after using gases,the temperature fields of the material layers will change.Then the quality of sinter will be influenced.In order to make effective use of fuel gas and ensure the quality of sinter,the first step of the project is based on the sintering raw material conditions,injecting a several common steel plant gases(blast furnace gas,converter gas,coke oven gas)into sintering layer,replacing some solid fuel,then calculating the material balance and heat balance.The conclusions are follow:Under the condition that the replacements of solid fuel are same,the higher the gas calorific value is,the less the usage amount is.After using gases,the total energy consumption decreases.After using the coke oven gas and natural gas,CO2 emissions decreases,the order CO2 emissions of is blast furnace gas,converter gas,natural gas,coke oven gas,coke oven gas is the best choice.The sintering process with gas injecting is simulated.Then the influences of amount,injecting position,gas flow are analyzed.The conclusions are follow:(1)Under the situation of certain injection position and gas flow,the effect of fuel substitutions(5%,10%,15%)on sintering process is investigated The result show as follows:with the increasing amount of solid fuel substitution,combustion zone is expanded,the temperature of material layer rise,and the quality of sinter get improved;in addition,with the increase of solid fuel substitution,the vertical sintering speeds decrease,exhaust temperatures decrease,the heat utilization rates increase.(2)Under the situation of certain fuel substitution and gas flow fuel,the effect of injection position(8.75m and 17.08m from the ignition furnace)on sintering process is investigated.The result show as follows:when injecting near the ignition furnace,combustion zone is expanded,the upper material layer has a higher combustion temperature,the lower layer temperature reduces,the quality of sinter can be improved.In addition,when injecting near the ignition furnace,the vertical sintering speeds becomes faster,and the temperature of tail gas changes little.(3)Under the situation of certain fuel substitution and injection position,the effect of gas flow(500s and 1100s)on sintering process is investigated.The result show as follows:after reducing gas flow,combustion zone became thinner.It is not conducive to improving the sinter quality when the temperature of the upper material layer decrease and the temperature of the lower material layer increases.In addition,after reducing the gas flow,the tail gas temperature increases,which is unfavorable to the full utilization of heat.In summary,coke oven gas injection can reduce the energy consumption of sintering process,reduce emissions of CO2.Injecting gas fuel early in the sintering process can improve the upper layer temperature,reduce layer temperature,increase the combustion zone width,improve the quality of sinter.After injecting fuel gas the vertical sintering speed becomes slower than before,so solid fuel substitution amount should not be too large,it should be about 10%,injection duration should be 500s.