| With the development of social economy,the situation of shortage of resources and increasing environmental load has been fully revealed.It is imperative to develop new technologies to gradually replace traditional technologies.Among them smelting reduction ironmaking technology is the main development object Smelting reduction ironmaking process can directly use non coking coal and iron ore powder to smelt hot metal.It has the advantages of short process flow,less production investment,low energy consumption and less environmental pollution.It is a cutting-edge ironmaking technology in contemporary iron and steel industry.Taking the iron bath smelting reduction furnace as the research object,this paper analyzes the combustion characteristics in the furnace by establishing the "upper space" combustion model,and studies the influence of different oxygen lance position,different oxygen enriched flow rate of top blowing and different inclination angle of oxygen lance inlet on the gas velocity distribution and temperature distribution in the furnace.At the same time,a three-dimensional multi-phase VOF model of the interaction between the smelting reduction process and slag in the "lower molten pool" was established.The effects of side blowing angle,gas flow rate and immersion depth of side lance on the surface velocity distribution of molten pool,internal flow of molten pool and transient characteristics of slag splashing were studied.(1)With the increase of the distance between the oxygen lance and the liquid level of the molten pool,the length of the combustion flame increases gradually,and the temperature of the flame also increases gradually.However,the distance between the oxygen lance and the liquid level of the molten pool should not be too large.The position of the oxygen lance is too high,and the high temperature flue gas is directly discharged from the upper space,resulting in the increase of coal consumption and heat loss.Therefore,the height of the oxygen lance should be between 1.2～1.4m.(2)With the increase of oxygen enriched flow rate,the temperature of combustion flame gradually decreases,and with the increase of gas flow rate,the maximum temperature of combustion flame gradually decreases.Therefore,when the oxygen enriched gas flow rate is 0.2kg/s,the temperature in the upper space of the furnace is the highest.(3)The oxygen lance inlet angle is 10° However,under other parameters,the temperature inside the furnace first increases and then decreases,and the temperature in the center of the furnace gradually decreases with the increase of the inclination angle,so the inclination angle of the oxygen lance inlet should not be greater than 15°.(4)The side blowing angle has a great influence on the velocity distribution on the molten pool surface,and 30° side blowing angle is 0.325m/s,but the springing phenomenon is distributed near the furnace wall,and the side blowing angle is 70° But there is a "dead zone"at the bottom of the molten pool,and the side blowing angle is 50° The results show that the stirring in the molten pool and the gushing and splashing on the surface have good effects.(5)The side blowing flow rate has a weak influence on the velocity distribution on the surface of the molten pool and the agitation inside the molten pool,but has a certain influence on the droplet splashing state on the surface of the molten pool.There is no splashing droplet on the surface of the molten pool with the side blowing flow rate of 0.0214Nm3/s,so the side blowing flow rate should not be less than 0.0214Nm3/s.(6)The immersion depth of side blowing lance has a weak influence on the velocity distribution on the surface of the molten pool and the agitation inside the molten pool,but has a certain influence on the droplet splashing on the surface of the molten pool.Although there are slag strips on the surface of 0.55m and 0.65m molten pool,no droplets are formed.Therefore,the submergence depth of side blowing angle should not be higher than 0.45m. |
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