运行参数对锅炉煤粉着火燃烧和飞灰含碳量影响的数值研究

Numerical Study of Operation Parameters on Pulverized Coal Ignition and Unburned Carbon in Fly Ash for a Boiler

为了达到锅炉的优化运行以保证煤粉气流及时着火和充分燃尽,采用IPSA两相流动模型和煤粉燃烧综合模型,在不同的一次风率和煤粉细度的工况下,对1台350MW锅炉煤粉燃烧过程进行了数值模拟,得出了炉内燃烧器区域以及出口处烟气温度场和燃烧产物的组分浓度分布。分析了一次风率和煤粉细度对煤粉着火燃烧和飞灰含碳量的影响规律,并确定了优化的运行参数。结果表明:一次风率对煤粉气流的着火影响较大,而对出口处烟气温度、氧量以及飞灰含碳量影响较小。煤粉细度对煤粉气流的着火、燃烧以及燃尽均有较大影响。

In order to obtain optimum operation of boilers and then ensure timely ignition and completely burnout of pulverized coal, pulverized coal combustion processes in a 350MW boiler were numerically calculated under different primary air ratios and pulverized coal fineness. The Inter Phase Slip Algorithm model was employed for the two-phase flow simulation. The comprehensive coal combustion models were used to simulate combustion process. The numerical results showed the temperature field and the combustion species' concentration distributions in the combustion zone and at furnace exit. The effects of primary air ratio and pulverized coal fineness on pulverized coal ignition and unburned carbon content in fly ash were studied and optimum operation parameters were given. The results illustrate that primary air ratio has a major effect on pulverized coal ignition and minor effects on gas temperature, oxygen concentration and unburned carbon at furnace exit. Pulverized coal fineness has significant effects on pulverized coal ignition, combustion and burnout. Figs 8, tables 2 and refs 9.