Carbon dioxide utilization technology of exhaust gas and industrial application in steelmaking plant
The characteristics of CO2 capture and utilization of exhaust gas in iron and steel plants was analyzed sys-tematically.The carbon dioxide utilization technology of exhaust gas was developed in Shougang Jingtang,and the CO2 captured from the tail gas of lime kiln played a metallurgical role in the combined blowing converter process.The CO2 concentration of the exhaust gas from the lime kiln increased from 23.5％to 99.8％using the comprehen-sive method of the pressure swing adsorption and cryogenic separation.Through a series of trials of bottom blowing and top blowing CO2 in converter,the effect of CO2 blowing parameters on the w([C])×w([O]),w((TFe))of the slag,w([N]),the heat change and converter tuyere erosion were researched.The best results for the value of w([C])×w([O]),slag w((TFe))and dephosphorization were achieved when the CO2 and O2 mixture was blown at a CO2 mixing ratio of 8.1％.The[N]content decreased with the extension of CO2 blowing time.The CO2 bot-tom blowing into the converter should be switched with Ar,and the blowing time of CO2 should be controlled in the early 12 min to avoid increasing the w([C])× w([O])value and the w((TFe))in the slag.The temperature drop is estimated to be 6.4-8.3 ℃/(m3·t).The physical heat of molten steel is converted into chemical heat and stored in the BOF gas CO.In order to utilize the cooling effect of bottom blowing CO2 to protect the bottom blowing tuyere and improve the reaction rate of CO2 and[C],CO2 should be blown in the high-speed decarburization period.In order to avoid the erosion of refractory,CO2 should be avoided at the final stage,for the metal oxides produced by the reaction between the CO2 and the molten steel result in a faster erosion of the refractory.
carbon capture in the steel industrypressure swing adsorptioncarbon dioxide utilizationCO2 blowing in convertertop and bottom blowing
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