HBS-LNSB Ⅲ 型旋流燃烧器回流区和着火距离的试验研究

Experimental Study on Recirculation Zone and Ignition Standoff Distance of HBS-LNSB Ⅲ Swirl Burner

针对某煤粉燃烧器的回流区和着火距离进行了试验研究。试验考查了中心风量、外二次风量、内二次风量以及内二次风旋流强度对回流区大小的影响规律,结果发现内二次风量的变化对回流区宽度的影响最大,中心风量对回流区与燃烧器的轴向距离影响最大。试验结果为不同煤种燃烧时的燃烧器配风选择提供依据。通过对各影响因素下煤粉着火距离的研究发现,针对着火距离短的易燃煤种,为了避免燃烧器喷口烧损,提高中心风量以及一次风速是最有效的措施。由于低负荷下炉内整体温度水平低,煤粉着火距离变长,可以适当提高易燃煤种的掺烧比例。对于着火温度较高的煤种,中心风量、内外二次风量的变化对于其着火距离均有明显的规律性,内二次风旋流强度的影响需要综合考虑旋流强度带来的风量变化的影响。不同煤种着火距离的工业试验为旋流燃烧器的配风选择提供了指导。煤种发生较大变化时应进行回流区与着火距离的工业试验,为燃烧器配风找到最优选择。

The experimental investigation of recirculation zone and ignition characteristics on a swirl burner were studied. The effects of central air quantity, external secondary air quantity, internal secondary air quantity and swirl intensity of internal secondary air on the size of recirculation zone were investigated. It was found that the change of internal secondary air quantity had the greatest influence on the width of recirculation zone while the change of central air quantity had the greatest influence on the distance between the recirculation zone and burner. The experimentation results provided a basis for the selection of air distribution for coal combustion with different combustion characteristics. The ignition standoff distance of pulverized coal under various influencing factors was studied. It was found that the ignition standoff distance of free-burning coal is short. In order to avoid burner port burning, the most effective measures are increasing the central air quantity and primary air velocity. Due to the low temperature of furnace, the ignition standoff distance of pulverized coal become longer and the blending ratio of free-burning coal can be increased at low load. For the coal with high ignition temperature, the changes of central air quantity, external secondary air quantity and internal secondary air quantity have obvious regular effects on ignition standoff distance. The influence of swirl intensity of internal secondary air must comprehensively consider the influence of air quantity change caused by swirl intensity. The industrial tests of different coal ignition standoff distance provide guidance for the selection of burner air distribution. Industrial test on ignition distance and recirculation zone should be carried out when the coal types change greatly in order to find the best choice for burner air distribution.