神府烟煤和云南劣质烟煤富氧分级燃烧特性试验研究

Experimental study on oxyfuelstaged combustion characteristics of Shenfu bituminous coal and Yunnan inferior bituminous coal

为探索富氧燃烧高效低氮燃烧的途径,在东方锅炉试验中心下行炉上开展神府烟煤、云南劣质烟煤的富氧分级燃烧特性试验研究,探索2种煤在富氧分级燃烧条件下的燃尽特性及氮氧化物排放特性。试验结果表明:在富氧燃烧条件下,采用燃尽风分级燃烧,合理控制氧气分级送入,神府烟煤燃烧效率可达99%以上,烟气中NO_(x)排放可控制在19.10 mg/MJ以内;云南劣质烟煤因着火延迟,燃尽需要足够长的停留时间,其燃烧效率略低,通过合理氧分级,燃烧效率最高可达90%以上,烟气中NO_(x)排放可控制在16.83 mg/MJ内;富氧燃烧炉膛温度对NO_(x)累积生成释放曲线的影响与空气燃烧一致,炉膛温度越高,煤粉颗粒升温速率越快;采用富氧分级燃烧,合理控制氧分级送入时机和位置,可寻找到较高的燃烧效率和较低的NO_(x)排放,实现富氧燃烧高效低氮排放。

In order to explore the way of high efficiency and low nitrogen combustion in oxy-fuel combustion,the experimental study on oxy-fuel staged combustion characteristics of Shenfu bituminous coal and Yunnan inferior bituminous coal was carried out on the down-draft furnace of Dongfang Boiler Test Center,and the burnout characteristics and nitrogen oxide emission characteristics of two kinds of coal under oxy-fuel staged combustion conditions were explored.The experimental results show that under the condition of oxy-fuel combustion,the combustion efficiency of Shenfu bituminous coal can reach more than 99%,and the NOx emission concentration in flue gas can be controlled within 19.10 mg/MJ by using over-fire air staged combustion and reasonable control of oxygen staged feeding.The combustion efficiency of Yunnan inferior bituminous coal is slightly lower due to the delay of ignition and the long enough residence time required for burnout.However,the combustion efficiency can reach more than 90%with reasonable oxygen classification,and the NOx emission concentration in flue gas can be controlled within 16.83 mg/MJ.The effect of furnace temperature of oxy-fuel combustion on the cumulative formation and release curve of NOx is consistent with that of air combustion.The higher the furnace temperature,the faster the heating rate of pulverized coal particles.The higher combustion efficiency and lower NOx emission concentration can be found by adopting oxy-fuel staged combustion and reasonably controlling the timing and position of oxygen staged injection,so as to achieve high efficiency and low NOx emission of oxy-fuel combustion.