高炉回旋区喷吹煤粉三维模拟

Three-dimensional Modelling of Pulverized Coal Injection in Blast Furnace Raceway

建立了高炉回旋区喷吹煤粉的气固两相流动、辐射和燃烧三维数学模型,用商业软件模拟了高炉回旋区内流场、温度场及组分变化,研究了鼓风富氧率、鼓风温度、鼓风速度对高炉回旋区的影响.结果表明,气体在回旋区内的流动可分为沿风口方向的高速射流区和在回旋区上部的回旋流动.回旋区内温度分布不均匀,回旋区下部温度较高,热量沿回旋区边界向上部传递.沿风口中心线O2不断被消耗,CO2含量随O2含量减少而增加,在O2基本耗尽时达到峰值.随CO不断生成,CO2含量逐步减少,直至消失.提高鼓风富氧率、鼓风温度及增加鼓风速度能促进煤粉燃烧,提高煤粉燃烧速度.

A three-dimensional mathematical model including gas-solid flow, radiation and coal combustion was established to simulate the pulverized coal injection in blast furnace raceway. With the help of commercial software, the flow field, temperature field and composition change in the raceway were simulated. The results showed that the flow pattern can be divided into two parts： a high-speed jet along the tuyere direction and a large-scale recirculation at the upper part of the raceway. The distributions of temperature field was not uniform, and the temperature was higher at the lower part of raceway and the heat transmits to the upper part along the boundary of the raceway. Oxygen was consumed constantly along the tuyere axis. The carbon dioxide content increased with the decrease of oxygen content and reached the maximum when the oxygen was almost exhausted. Then, the carbon monoxide content increased rapidly with the carbon dioxide content decreased. The increase of blast oxygen enrichment, blast temperature and blast rate can promote the combustion of pulverized coal and increase the burning speed of pulverized coal.