为了解决目前回转窑-矿热炉工艺流程中存在 CO2、NOx排放量高、煤耗大等问题,基于计算流体力学(CFD)、多反应耦合条件,结合回收矿热炉炉气 CO 等可燃成分的净化装置,采用SolidWorks 软件建立回转窑三维物理模型,利用 ICEM 软件对物理模型进行网格划分,建立了回转窑炉气-煤粉气固两相燃料混合燃烧模型,使用FLUENT软件开展回转窑中废气再燃技术的数值研究,探究废气再燃技术对回转窑煤耗量和烟气成分的影响.结果表明:焙烧区域在温度满足实际生产的前提下,此节能系统可将回转窑的NOx排放量由0.100 9%(体积分数)降低至0.057 4%(体积分数);回收矿热炉炉气中余热能量约为78.411 GJ·h-1;回转窑的烟煤损耗量可减少3.7 t·h-1,约占总煤耗量的40.6%;每年减少的CO2排放量和灰渣等固体废弃污染物排放量分别为69 796、1 750 t.
Energy Saving System for Recycling Electric Furnace Gas as Auxiliary Fuel for Rotary Kilns
In order to solve the problems of high CO2,NOx emissions and high coal consumption in the current rotary kiln-electric furnace process,based on computational fluid dynamics(CFD),multiple reaction coupling and combined with the purification device for recovering combustible components such as CO from electric furnace gas,SolidWorks software was used to establish a three-dimensional physical model of the rotary kiln,ICEM software was used to mesh the physical model,a co-combustion process of the gas-solid fuel in the rotary kiln was established,and FLUENT software was combined to carry out numerical research on waste gas reburning technology in the rotary kiln,the impact of exhaust-gas reburning technology on coal consumption and flue gas composition in rotary kilns was explored.The results showed that under the premise of meeting the actual production requirements in the roasting area,this energy-saving system could reduce the NOx emissions at the outlet of the rotary kiln from 0.100 9%(volume fraction)to 0.057 4%(volume fraction);the residual heat energy in the recovery of electric furnace gas was 78.411 GJ·h-1;the coal consumption in the rotary kiln was reduced by 3.7 t·h-1,accounting for approximately 40.6%of the total coal consumption;the annual reduction in CO2 emissions and solid waste pollutants such as ash was 69 796 t and 1 750 t,respectively.
RKEFFlue gas purificationResidual heat energy recyclingExhaust-gas reburning
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