气烧石灰竖窑的数值模拟及优化研究

Study on numerical simulation and optimization of gas burning lime kiln

将气烧石灰竖窑中的石灰石处理为多孔介质,多孔介质能量方程选用单温度方程,以源项的形式添加石灰石分解反应,将分解反应热添加到能量方程中。通过建立能量源项的自定义函数,实现在单温度方程中以非定常能量源项来表示石灰石分解反应吸收热量的目的。研究结果表明,添加能量源项后,石灰窑中出现了明显的三带分布,即从窑底到烟气出口依次为冷却带、煅烧带、预热带,且煅烧带中的温度维持在1200~1500 K;在此基础上,得到了该型石灰窑的最佳运行工况参数,即当高炉煤气质量流量为0.127 kg/s、助燃风与冷却风的流量比为2∶3、助燃风和冷却风质量流量分别为0.0970 kg/s和0.1455 kg/s时煅烧效果最佳。

Limestone in gas burning lime kiln was regarded as porous medium, the equation of the single temperature was chosen as the energy equation of the porous medium, the decomposition reaction of limestone was added in the form of source terms, and the chemical reaction heat was added to the energy equation. With the establishment of the user defined function of tbe energy source term, the purpose was realized by adding an unsteady energy source term in single temperature equation to balance the heat of absorption of the limestone decomposition reaction. Conclusion showed, af- ter adding the energy source, there were obvious three zones in the lime kiln which were the cooling zone, the calcina- tion zone and the preheating zone from the bottom of the kiln to the flue gas outlet, and the temperature in the calcina- tion zone was maintained in 1200~ 1500 K. The lime kiln optimum operating parameters was obtained on the basis of this, and when the blast furnace gas mass flow was 0. 127 kg/s, and combustion air and cooling air flow ratio was 2 ： 3, the best calcining was that combustion air and cooling air mass flow were 0. 0970 kg/s and 0. 1455 kg/s.