摘要
针对福斯特惠勒(FW)技术W型火焰锅炉燃烧稳定性差、飞灰含碳量高、炉宽方向氧量存在偏差等问题,结合数值模拟对锅炉燃烧特性进行了分析与研究。结果表明:F二次风下倾角度增大,其对一次风火焰的抬升作用会减小,一次风火焰下冲明显增加,燃烧器出口烟气回流区变大,烟气回流更加强烈,对一次风气流的着火稳燃性能有明显作用,但效率提高不明显;由于W型火焰锅炉的流场特性,随着F二次风下倾角度的增加,一次风与二次风的混合延迟且强度变小,炉膛宽度方向上中间与侧边的氧量偏差随之变大,F二次风沿炉宽方向的非均等布风不能缓解氧量偏差;F二次风下倾对火焰中心没有明显影响;切除侧边的4只燃烧器后一次风火焰下冲有明显加强,火焰中心下降明显。
The issues of poor combustion stability,high carbon content of fly ash and oxygen content bias in furnace width direction occurred in a Foster Wheeler(FW)down-fired boiler.Thus,numerical simulation was conducted to analyze the combustion characteristics of this boiler.The results showed that,with an increase in F secondary air declination angle,the uplifting of the secondary air to primary air flame was reduced,the undershoot of the primary air flame increased significantly,the recirculation zone of the flue gas at the burner outlet got larger,the return of the flue gas was intensified,which had an obvious effect on combustion stability of the primary air but not on the efficiency enhancement.Due to the flow field characteristics of this down-fired boiler,with the increasing F secondary air declination angle,the mixture of the primary air and secondary air delayed and the intensity weakened,and the oxygen content difference between the intermediate and side location in furnace width direction increased.The non-equalization distribution of the F secondary air along the width direction of the furnace can not alleviate the oxygen bias.The declination of the F secondary air had no obvious effect on position of the flame center.After the four side burners was removed,undershoot of the primary air flame significantly increased,and the flame center position dropped dramatically.
出处
《热力发电》
CAS
北大核心
2013年第9期38-44,共7页
Thermal Power Generation
关键词
W型火焰锅炉
燃烧特性
一次风
二次风
流场特性
数值模拟
W flame
combustion characteristics
primary air
secondary air
declination
numerical simulation
