Abstract: The staged oxygen entrained flow coal-slurry gasifier has advantages such as higher carbon conversion rate, stronger turbulent mixing inside gasifier and lower temperature near coal slurry nozzle. In this article, effects of the secondary oxygen mass flow rate on gasification performance were numerically investigated through CFD simulation. The characteristics of the gasification flames were analyzed as well as the flow field under different secondary oxygen mass flow rate in the staged gasifier. As the mass flow rate of the secondary oxidizer decreases, the secondary gasification flame curves up with the backflow near the wall. At the same time, dome wall temperature increases as well. When the mass flow rate of the secondary oxidizer is less than 8% of the total oxidizer mass flow rate, the effect of the secondary oxidizer is too weak to change the macro flow field.

Key words: numerical simulation, stagedentrained flow coal gasifier, secondary oxygen, flow field in gasifier

摘要： 分级给氧气流床气化炉具有碳转化率高、炉内混合过程强烈、喷嘴附近温度较低等优点。本文采用CFD数值模拟的方法研究了二次氧量变化对气化炉运行特性的影响，分析比较了不同二次给氧量下相交射流火焰特性的变化，及相交射流对煤气化炉炉内整体混合过程、煤气化特性的影响。发现当二次给氧量下降时，受炉内回流流场的影响，二次火焰明显随回流发生偏斜，壁面温度升高。当二次给氧量小于总给氧量的8%时，其射流动量不足以影响主射流产生的宏观流场。

关键词: 数值模拟, 分级气流床气化炉, 二次给氧, 气化炉流场