煤粉在直吹管内燃烧行为的数值模拟

Numerical Simulation of Pulverized Coal Combustion in Blowpipe

建立了直吹管内气固流动、传热和煤粉燃烧的数学模型,基于实际高炉工艺参数,借助商业软件通过数值模拟的方法研究了直吹管内的气体成分和温度变化,并重点考察了煤粉粒径、鼓风含氧量和鼓风温度等操作参数对煤粉燃尽率的影响。研究结果表明:减小粒径、增加含氧量、提高鼓风温度都可以使煤粉在直吹管内的燃尽率得到提高。煤粉在直吹管内的燃烧行为以挥发分的脱除为主,该过程对温度敏感,而对氧气浓度不敏感。这一结论与前人在回旋区内得到的模拟结果相反。因此在研究变量对喷吹煤粉燃尽率的影响时,模拟区域应同时包含直吹管和回旋区。

A mathematical model of the gas-solid flow,heat exchange and pulverized coal combustion in blowpipe was developed. Based on the technological parameters of practical blast furnace, by the way of numerical simulation,influ ences on the burnout of pulverized coal caused by the change of operating parameters such as particle diameter,oxygen enrichment and blast temperature were investigated with the help of business software. The variations of gas composition and temperature in blowpipe were also studied. The results indicate that the decreasing of particle diam eter, the increasing of oxygen enrichment and blast temperature all can raise coal burnout. The main transformation of pulverized coal in blowpipe is devolatilization, which is sensitive to temperature, while insensitive to oxygen concentration. This conclusion is contrary to the simulation results of predecessors got in raceway. During the study of the influence of vari ables on pulverized coal burnout, the simulation region should contain both of blowpipe and raceway.