Study On High Efficiency And Clean Combustion Mechanism Of Steel-making Converter Gas

In the steelmaking process of top-blown oxygen converter,a large amount of high temperature converter gas is produced,and the converter gas contains high concentration of CO,which is a valuable secondary energy source.However,when converter gas burns with air,due to the existence of N₂ in the air,it is easy to produce polluting gases such as NO_x,and CO is difficult to burn completely.CO,which is not completely burned,will also cause harm to the environment and reduce the combustion efficiency of furnace gas.Therefore,in order to realize the efficient and clean combustion of converter gas,it is of great significance to study the main factors affecting converter gas combustion,and to improve the combustion efficiency of converter gas,and reduce the emission of polluting gas.In this paper,a numerical model of converter gas combustion in converter is established,and the process of converter gas combustion in converter is simulated by using this model.When the concentration of water vapor in air and the inlet temperature of converter gas change,the effects on converter gas combustion(CO combustion efficiency,NO_x generation rate,maximum flame temperature in furnace)are studied,and how to realize efficient clean combustion of converter gas is discussed.The results show that when the concentration of water vapor in air increases from 0%to 5%,the emission concentrations of CO and NO,N₂O,NO₂decrease and the peak temperature of flame in the furnace decreases.CO emission decreases sharply when concentration of water vapor in air increases from 0 to0.4%.At concentration of water vapor>0.4%and inlet temperature<950K,for the reduction of CO emission,the inlet temperature of converter gas is predominant over that of H₂O vapor in air.The inlet temperature of converter gas has noticeable influence on NO emission at the concentration of water vapor<2%.With the increase of the concentration of water vapor,NO emission first increases,then reaches a peak value,finally decreases.At inlet temperature>1050K and the concentration of water vapor>2%,NO emission noticeably decreases with the concentration of water vapor.In the presence of water vapor,a large amount of H and OH free radicals are produced,CO is mainly oxidized by the OH free radical to produce CO₂,so that the emission concentration of CO is reduced.At the same time,the existence of water vapor reduces the maximum temperature of flame and the formation of thermal NO_x.In the presence of H₂O,H and OH free radicals are easily formed,the reduction path of NO is as follows:NO?NH/HNO?N₂.The results show that the concentration of water vapor in air and the inlet temperature of converter gas not only have an important influence on the combustion of converter gas,but also obtain their influence laws,and analyze their influence mechanisms from the aspects of thermodynamics and chemical mechanism,which has engineering guiding significance for realizing the efficient clean combustion of converter gas and the development direction of steelmaking converter in the future.It also promotes the recognition of the importance of water vapor affecting combustible gas combustion,which is of scientific significance to a certain extent.