外燃式微油点火燃烧器机理及应用

Application and mechanism of external tiny-oil ignition burner

针对火电厂煤粉锅炉冷态节油点火、低负荷稳燃、煤种适应性提高、低NOx运行等要求,开发了新型外燃式微油点火燃烧器,点火燃油量在100 kg/h左右,该燃烧器同时作为主燃烧器使用,并具有低负荷稳燃与低NOx功能。5台锅炉的工业应用结果表明,外燃式微油点火燃烧器可实现锅炉冷态点火,煤粉燃尽率在82%以上,可实现不投油自然停炉,NOx下降率为25%左右,结合燃尽风后NOx下降率达55%左右。中心风是该燃烧器的主要调节手段,数值计算表明,调节中心风可以改变燃烧器出口回流区长度,从而调节煤粉着火点位置。

According to the requirement of less oil ignition, lower load combustion stabilization, and more coals suitability for power plant boilers, a new external tiny-oil （about 100 kg/h ） ignition burner was developed. The new burner is also main burner of a boiler with the ability of low load combustion stabilization and low NOx emission. The results of the applications in 5 boilers showed that the external tiny-oil ignition burner could start boilers in cold condition with upon 82% burnout of pulverized-coal. The burners could shutdown boiler directly without oil. The NOx emission could be cut down about 25%, and about 55% with OFA. The center-air is the primary method to control combustion. The CFD study showed that the velocity of center-air could change the recirculation zone size effectively, so it could control the ignition point to proper position for the safety of burner.