以往针对氨煤掺烧研究多集中在数值模拟及小型试验炉,大型试验炉上多为技术可行性的点工况试验。在一台50kW自持燃烧下行试验炉中在不同工况下针对燃煤掺氨燃烧产物的排放和过程分布特性展开研究,重点分析了不同掺氨比例、燃尽风率及运行氧量的影响。为充分了解氨与煤燃烧过程中对NO生成的贡献,针对纯氨燃烧进行一系列试验。试验结果表明,空气分级燃烧可大幅降低燃煤掺氨燃烧NO的排放,掺氨比例为10%~90%时NO排放质量浓度在170~215mg/m3,同纯煤燃烧NO排放质量浓度处于同一水平;最佳燃尽风比率维持在38%附近,继续增大燃尽风比率不会进一步降低NO排放,反而会导致燃烧不充分等负面影响。纯氨燃烧利用空气分级技术可以很好地控制出口NO浓度,但纯氨燃烧稳定性远不及氨煤掺混燃烧,运行氧浓度较低时易出现氨逃逸现象。燃煤掺混氨燃烧既可解决氨燃烧困难、出口NO排放浓度过高的问题,又可减少燃煤CO2排放,是一项极具潜力的技术路线。

Previous studies on ammonia/ coal co-firing have focused on numerical simulations and small-scale test furnaces, while large-scale test furnaces are mostly used for point-case tests of technical feasibility. In this paper, a detailed study of the emission and processdistribution characteristics of ammonia/ coal co-firing was carried out in a 50 kW one-dimensional self-sustained combustion experimentalfurnace under different operating conditions. In order to fully understand the contribution of ammonia and coal to NO production duringthe combustion process, a series of experimental studies were carried out for pure ammonia combustion. Air-staged combustion greatly reduces NO emissions from ammonia/ coal co-firing combustion. With ammonia co-firing ratios ranging from 10% to 90%, NO concentrations varie from 170 to 215 mg/ m3, which are at the same level with pure coal combustion. The optimal burnout air ratio is maintainednear 38%. Further increasing the burnout air ratio will not further reduce NO emissions, but will lead to negative effects such as inadequate combustion. Pure ammonia combustion employing air-staged combustion technology can manage the exported NO concentration, butits stability is significantly worse than that of ammonia/ coal co-firing, and ammonia is prone to escape when the oxygen concentration inthe operation is low. Ammonia/ coal co-firing may not only solve the problems of ammonia combustion difficulties and excessive NO emissions, but it can also minimize CO2 emissions from coal combustion, making it a very attractive technology route for future energy growth.

0 引言

1 试验

   1.1 试验系统

   1.2 试验方法

2 试验系统和研究方法

   2.1 燃煤掺混氨燃烧

   2.2 纯氨燃烧

3 结论