Beijing Tiandi Rongchuang Technology Corporation Ltd
National Energy Technology and Equipment Laboratory of Coal Utilization and Emission Control
State Key Laboratory of High Efficient Mining and Clean Utilization of Coal Resources

开发高效清洁的煤粉燃烧技术是实现“双碳”目标的有效途径之一,空气分级燃烧技术在煤粉燃烧初期形成还原性气氛且能有效抑制NOx的生产但不利于煤粉燃烬,而采用富氧分级燃烧可延长煤粉在还原性气氛中的停留时间并抑制NOx的生成及促进煤粉燃烬,因而很有必要研究二次风过量氧气系数、二次风氧气体积分数、空气分级系数等因素对煤粉富氧分级燃烧NOx排放的影响规律。利用两段式滴管炉,研究滴管炉上段处于1300℃时富氧分级燃烧条件下NOx的排放规律。实验结果表明:不同分级系数条件下,NOx排放浓度最低对应的最佳二次风氧气体积分数(c2)随二次风过量氧气系数(α2)的减小而增大。当α2>0.6时,NO排放浓度随二次风氧气体积分数的增加而增大;当α2=0.4~0.5时,NO排放浓度随二次风氧气体积分数的增加呈先减小后增加的趋势;当α2<0.3时,NO排放浓度随二次风氧气体积分数的增加而减小。富氧分级燃烧能显著降低NO的排放,α2=0.3~0.6时,NO减排比例均高于75%,当α2=0.3~0.5且c2=50%~100%时,NO减排比例均高于85%,且飞灰含碳量均低于8%。烟气中N2O和NO2的排放浓度均相对较低,在富氧分级条件下NO2的排放可忽略不计,N2O排放浓度随二次风过量氧气系数的增加而降低,且增大氧气体积分数也能进一步抑制N2O排放。

Developing efficient and clean coal powder combustion technology is one of the effective approaches toachieve the goal of carbon peaking and carbon neutrality. Air staged combustion technology forms a reducing atmos⁃phere in the early stage of coal powder combustion and can effectively suppress NOx production, but it is not condu⁃cive to coal powder burnout. Using oxygen⁃enriched staged combustion can prolong the residence time of coal powderin the reducing atmosphere, inhibit NOx generation, and promote coal powder burnout. Therefore, it is necessary tostudy the secondary air excess oxygen coefficient, secondary air oxygen concentration and air classification coefficienton NOx emissions from oxygen-enriched staged combustion of coal powder. In this paper, a two⁃stage high tempera⁃ture dropper furnace was used to study the NOxemission of fractional combustion of pulverized coal under the conditionof 1 300 ℃ and oxygen⁃enriched. The experimental results show that the optimal secondary air oxygen concentration(c2) corresponding to the lowest NOx emission concentration increases with the decrease of the secondary air excessoxygen coefficient (α2). When α2 >0. 6, NO emission concentration increases with the increasing of secondary airoxygen concentration. When α2 = 0. 4-0. 5, NO emission concentration decreases first and then increases with the in⁃crease of secondary air oxygen concentration. When α2<0. 3, NO emission concentration decreases with the increaseof secondary air oxygen concentration. Oxygen⁃enriched staged combustion can significantly reduce NO emissions.When α2 = 0. 3-0. 6, the NO reduction ratio is higher than 75%. When α2 = 0. 3-0. 5 and c2 = 50%-100%, the NOreduction ratio is higher than 85%, and the carbon content of fly ash is lower than 8%. The emission concentration ofN2O and NO2in the flue gas is relatively low, and the emission of NO2 is negligible under the oxygen-enriched classi⁃fication condition. The emission concentration of N2O decreases with the increase of the secondary air excess oxygencoefficient, and increasing the oxygen concentration can also further reduce the N2O emission.

北京天地融创科技股份有限公司科技发展基金重点资助项目(2022JNZD-01)

龚艳艳. 煤粉富氧分级燃烧 NOx排放特性研究 [J]. 煤质技术, 2023, 38 (3): 20-27.

GONG Yanyan. Research on NOx emission characteristics of pulverized coal oxygen-enriched staged combustion[J]. Coal Quality Technology, 2023, 38 (3): 20-27.