氨作为燃料部分或全部替代化石燃料是减少二氧化碳的有效途径之一，氨煤共燃研究具有重要意义。氨的燃烧特性与煤粉有很大不同，导致氨与煤粉气流的着火和排放特性与传统煤粉火焰不同。本文在平焰燃烧器上实验研究了煤氨混合燃烧射流中煤粉浓度对着火距离和喷射火焰不同位置气相成分的影响，并研究了着火条件和着火稳定性。阐述了煤和氨气-固体燃料的制备方法。结果发现，氨与煤粉的混合改变了平焰燃烧器的温度场，从而改变了射流的点火特性。相同射流速度下的着火延迟时间与煤粉浓度呈正相关，但当煤粉浓度继续降低时，对着火延迟时间的影响逐渐变小。煤氨气-固体燃料的成分改变了燃烧过程中的传热路径和份额，最终导致火焰温度与煤粉浓度呈负相关。因此，煤粉浓度的降低有利于煤氨混合燃料的稳定燃烧。当HAB=100 mm时，单位质量煤氨混合物燃料N向NO x的转化率随着煤粉浓度的增加而增加。 随着煤粉浓度的增加,NO x生成量先增加后减少,而N 2 O和NO 2的生成量随着HAB的增加而迅速减少。 NOx中NO的比例超过94%，有利于实现煤和氨气固体燃料的低氮燃烧。总体而言，掺氨后氨煤喷射火焰中O 2浓度降低，烟气温度升高，NO x和CO生成量增加，本实验最佳煤粉浓度为0.41 kgc/kga（煤粉质量比）。煤至N 2和NH 3之和)。
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Experimental Study on Flame Chemical Composition of Coal and Ammonia Gas–Solid Jet in Flat Flame Burner
Ammonia as a fuel to partially or completely replace fossil fuels is one of the effective ways to reduce carbon dioxide, and the research on ammonia coal cocombustion is of great significance. The combustion characteristics of ammonia are very different from those of pulverized coal, resulting in the ignition and emission characteristics of ammonia and pulverized coal gas flow that is different from traditional pulverized coal flame. In this paper, the effect of pulverized coal concentration in coal and ammonia mixed combustion jet on the ignition distance and gas-phase components at different positions of the jet flame were studied experimentally on the flat flame burner, and the conditions of ignition and ignition stability of coal and ammonia gas–solid fuel were expounded. It was found that the ammonia mixed with pulverized coal changed the temperature field of the flat flame burner and therefore the ignition characteristics of the jet were changed. The ignition delay time at the same jet speed was positively correlated with the pulverized coal concentration, but when the pulverized coal concentration continued to decrease, the influence on the ignition delay time gradually became smaller. The composition of coal ammonia gas–solid fuel changed the heat transfer path and share during combustion, and finally, the flame temperature was negatively correlated with the concentration of pulverized coal. Therefore, the reduction of the pulverized coal concentration was conducive to the stable combustion of coal ammonia mixed fuel. When HAB = 100 mm, the conversion rate of fuel N to NOx per unit mass of coal ammonia mixture increased with the increase of pulverized coal concentration. The NOx production amount first increased and then decreased with the increase of pulverized coal concentration, and the amount of N2O and NO2 decreased rapidly with the increase of HAB. The proportion of NOx in NO exceeded 94%, which was conducive to achieving low nitrogen combustion of coal and ammonia gas–solid fuel. In general, the O2 concentration in the ammonia coal jet flame decreased, the flue gas temperature, and NOx and CO generation increased after mixing ammonia, and the optimal pulverized coal concentration in this experiment was 0.41 kgc/kga (mass ratio of pulverized coal to the sum of N2 and NH3).
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