循环流化床低热值煤—高热值煤粉动态复合燃烧污染物排放特性

Study on the Pollutant Emission Characteristic under the Dynamic Compound Combustion of Low Calorific Coal-High Calorific Pulverized Coal

为研究循环流化床（CFB）锅炉复合燃烧模式下的负荷动态变化特性及污染物排放特性，以240t/h循环流化床锅炉为研究对象，开展了低热值煤-高热值煤粉动态复合燃烧试验，在锅炉给煤口处和二次风口处设置煤粉给入点，分析不同的给煤粉位置、煤粉热值和煤粉与原煤阶跃热量比值对于CO、NOx和SO2排放浓度的影响。研究表明，在二次风口处给入煤粉时CO排放浓度较低，NOx、SO2排放浓度较高；煤粉热值增加时，两种煤粉送入方式下，CO排放浓度降低，NOx和SO2排放浓度有所升高；煤粉与原煤阶跃热量比例增加时，CO排放浓度降低，NOx、SO2排放浓度也有所升高。

The dynamic compound combustion experiment of low calorific value coal-high calorific value pulverized coal were carried out, and the dynamic load variation characteristics and pollutant emission characteristics of CFB boiler under compound combustion mode were studied. The pulverized coal feeding point was arranged at the coal feeding port and the secondary air outlet of the 240 t/h circulating fluidized bed boiler, and the influence on the emission concentration of CO, NOx and SO2 from the different pulver- ized coal location, the calorific value of pulverized coal and the step heat ratio of pulverized coal to coal were investigated. The result shows that the CO concentration reduces and the NOxand S02 concentration increase when the pulverized coal is injected at the two air outlets, but the change is little. When the calo- rific value of pulverized coal increases, the concentration of CO emission decreases and the emission con- centrations of NOx and SO2 increase with the two pulverized coal feed modes. When the proportion of pul- verized coal and the step heat of coal increase, the concentration of CO emission decreases, and the con- centrations of NOx and SO2 also increase.