煤粉预热低氮燃烧技术是燃烧技术领域的研究重点。为了响应“节能环保、绿色低碳经济”的时代发展要求，针对煤炭燃烧过程中产生大量污染物如NO_x、SO_x等环境问题，基于前人研究结果，设计开发了一种多级调风预燃式旋流燃烧器。耦合预燃室煤粉预热燃烧技术与空气分级燃烧技术，生成高还原性氛围回流区，在有效控制NOx生成的同时，提升难燃煤种着火性能。主要通过冷态模型试验，研究了不同配风比对多级调风预燃式旋流燃烧器空气动力场的影响，利用新型三孔探针测速方法进行了流场测试与分析。结果表明：在总风量一定的情况下，一次风率、旋流内二次风率及外二次风率分别为20.8％、37.5%和31.2%时，回流区长度、宽度、面积和回流率达到最大值，回流效果最好，有利于煤粉着火与低NO_x燃烧。预燃室的存在有利于形成煤粉稳定燃烧的回流区，其中旋流内二次风是影响回流区气流特性的主要因素，主导形成预燃室内的中心回流区；外二次风通过卷吸炉膛内的气流影响预燃室回流区温度，是预燃室内外围回流区生成的根本原因；具有一定刚性的一次风和直流内二次风会压缩回流区，影响燃烧器的稳燃效果。

Pulverized coal preheating low-nitrogen combustion technology is the research focus of combustion technology. In order to respond to the era development requirements of "energy saving,environmental protection,green and low-carbon economy",and solve the environmental problems of a large number of pollutants produced during the combustion process of coal such as nitrogen oxides and sulfur oxides,a multi-stage air-regulated pre-combustion swirl burner was designed and developed on the basis of a large number of previous studies on preheating combustion technology. The pre-combustion chamber pulverized coal preheating combustion technology is coupled with the air staged combustion technology to generate a highly reducing atmosphere recirculation zone,effectively controlling the generation of NO_x,and improving the ignition performance of refractory coals. In this paper,the influence of different air distribution ratios on the aerodynamic field of the multi-stage air-regulated pre-combustion swirl burner was mainly studied through the cold state model test,and the flow field was tested and analyzed by using the new three-hole probe velocity measurement method to carry out. The results show that under the condition of the constant total air volume,when the primary air rate,the swirl internal secondary air rate and the external secondary air rate are 20.8%,37.5% and 31.2%,the length,width,area and return flow of the recirculation zone reach the maximum,and the the reflux effect is the best,which is conducive to pulverized coal ignition and low NO_x combustion. The existence of the pre-combustion chamber is conducive to the formation of a recirculation zone for stable combustion of pulverized coal,and the swirl internal secondary air is the main factor that affects the airflow characteristics of the recirculation zone,which dominates the formation of the central recirculation zone in the precombustion chamber. The external secondary air affects the temperature of the recirculation zone of the precombustion chamber through the airflow in the suction furnace,which is the fundamental reason for the generation of the peripheral recirculation zone in the precombustion chamber. The primary air with a certain rigidity and the secondary air in the direct current will compress the recirculation zone and affect the combustion stabilization effect of the burner.

0 引言

1 试验

   1.1 试验系统

   1.2 试验工况

   1.3 数据处理

2 结果与分析

   2.1 一次风率与旋流内二次风率配比

   2.2 一次风率与外二次风率配比影响

   2.3 旋流内二次风率与外二次风率配比影响

3 结论