液态排渣炉燃烧过程的数值模拟  

Numerical simulation of combustion process for a slag tapping boiler

作　　者：李代力[1] 王智化[1] 许岩韦[1] 曹欣玉[1] 黄镇宇[1] 周俊虎[1] 岑可法[1] 

机构地区：[1]浙江大学能源清洁利用国家重点实验室,浙江杭州310027

出　　处：《浙江大学学报（工学版）》2013年第2期280-286,共7页Journal of Zhejiang University：Engineering Science

摘　　要：针对一台液态排渣旋风炉在不同配风方案下炉内燃烧过程和NOx分布进行三维数值模拟分析,建立液态排渣旋风炉内的流动和燃烧的数学模型,针对近壁燃烧的情况采用trap方式对炉内随气流运动的颗粒进行壁面捕捉.计算结果详细描述炉内的流场组织、温度场、氧气质量分数及不同配风情况下的NOx分布情况,并与该炉运行实验数据进行比较验证.计算结果显示,3种配风方式下液态排渣炉的燃烧均较为完全;相比较其他配风方式而言,分级配风方式下燃烧温度场分布更为均匀,顶部旋流二次风和切向二次风的共同作用加强了炉内气流的扰动,强化了炉内燃烧,使得整个炉膛的温度水平均维持在较高温度段,能够提供足够高温的烟气以满足裂解要求;同时下2层二次风强化了炉内水煤浆颗粒的燃烧,能够更好的抑制NOx的生成,采用分级配风方式下炉膛出口NOx质量浓度可低至684mg/m3,可以有效减少NOx排放.In order to investigate the combustion process and NOx formation properties in a coal water slurry fired slag tapping boiler, a three dimensional computational fluid dynamics （CFD） simulation work was conducted. Standard k-ε turbulence model and non-premixed combustion model was used here. Specially, for the treatment of particle during the slag tapping combustion process, particle trapping method was used for the surface boundary condition. The flow field, temperature and oxygen distribution as well as NOx in the furnace were analyzed and validated with real case experimental data. Results show that the combustion process in the furnace are all complete at the three different air feeding modes. Compared to typical air feeding conditions, temperature distributes in the furnace is more uniform at staged air method. The swirl secondary air on the top together with tangential secondary air enhances the airflow distribution in the furnace. This also enhances the combustion process and maintains the whole furnace running at a high temperature level, which is need by the downstream petroleum cracking process. The exiting of downstream secondary air enhances the burn out of the coal particles and inhibits NO, emission to 684 mg/m3 at staged combustion mode. Therefore, the coal water slurry fired slag tapping boiler can be running well at staged combustion mode with uniform temperature distribution and low NO; emission.

关 键 词：旋风炉 数值模拟 液态排渣 燃烧 水煤浆 

分 类 号：TK229[动力工程及工程热物理—动力机械及工程]