微波提质对褐煤燃烧特性影响

Effect of microwave upgrading on combustion characteristics of lignite

为了探究微波提质对褐煤燃烧特性的影响,对高含水褐煤进行了微波提质,并对比了不同给料量下提质煤中试燃烧特性。利用隧道式微波辐照系统对褐煤进行25 min的微波提质,在分析提质前后煤质组成、热值、灰成分、灰熔点以及微观表面形态特征的基础上,利用浙江大学1 MW卧式筒形热态试验炉进行中试燃烧试验,分析了提质煤的温度场分布、灰渣特征和污染物排放情况。结果表明:提质后褐煤的水分明显降低,热值升高,表面变得松散,比表面积增加,更容易着火燃烧,易形成熔融状结渣,更易燃尽;提质后CO排放质量浓度增加,SO_2排放质量浓度无明显变化,NO_x排放质量浓度明显下降。

In order to investigate the effect of microwave upgrading on combustion characteristics of lignite, the high-water content lignite was microwave upgraded, and pilot-scale combustion characteristics of the upgraded coal at different coal feeding rates were compared. Lignite has been treated by tunnel microwave irradiation system for 25 minutes. The composition of coal, calorific value, ash composition, ash melting point and microscopic surface morphology before and after microwave upgrading were analyzed. On this basis, the 1 MW horizontal cylindrical furnace for thermal test at Zhejiang University was used for the pilot-scale combustion experiment. Then the temperature distribution, ash characteristics and pollutant emissions of the upgraded coal were analyzed. The results show that, after microwave upgrading, the water content of the upgraded lignite decreases, the calorific value increases, the surface becomes loose, and the specific surface area increases. In addition, the upgraded ignite is easier to be ignited, form molten slag and burn out. Moreover, the concentration of SO_2 emission has no obvious change before and after the microwave upgrading, while the concentration of CO emission increases and the concentration of NO_x emission decreases obviously.