一次风温对浓淡煤粉射流着火特性的影响

Effect of Primary Air Temperature on Ignition Characteristics of Bias Pulverized Coal Jets

为了进一步完善煤粉的燃烧理论,并为相关的水平浓淡煤粉燃烧器的合理运行提供理论依据,针对印度尼西亚次烟煤与澳大利亚烟煤的混煤,在250k W浓淡煤粉燃烧实验台上进行燃烧实验,通过燃烧温度、火焰光谱及NOx等多手段的研究方法,分析一次风温对还原性气氛下浓淡煤粉射流着火特性的影响。实验表明：随着一次风温增加,浓淡煤粉射流的着火距离逐渐减小,后续燃烧温度及可见光强度的峰值逐渐增加,火焰稳定性逐渐增强,着火过程中NOx的生成浓度逐渐减少。一次风温的增加可以改变浓淡煤粉射流的着火模式,即一次风温70℃时为均相着火时,浓淡煤粉射流为均相着火,一次风温大于或等于85℃时着火模式为均相–异相联合着火,使得着火条件变得更加有利。

To further advance pulverized coal （PC） combustion theory and guide the operation of horizontal bias combustion PC burner, combustion experiments were conducted in a 250kW bias combustion simulator; combustion temperatures, flame spectra and NOx were investigated. A blend of sub-bituminous coal from Indonesia and bituminous coal from Australia was tested. The effects of primary air temperature （PAT） on the ignition characteristics of bias PC jets in a reducing atmosphere were investigated. The results indicate that with increasing PAT, the standoff distance gradually decreased, the peaks of subsequent combustion temperature and visible-light intensity gradually increased, the flame stability gradually increased and the NOx formation during ignition process became less. The increasing of PAT changed the ignition mode of bias PC jets, there was homogeneous ignition mode at PAT of 70℃; while PATs was no less than 85℃ the ignition mode changed to homogeneous- heterogeneous combined ignition, which is beneficial to the ignition.