不同特征燃料宽范围掺氨富燃污染物排放特性及动力学分析

doi:10.11949/0438-1157.20251092

摘要/Abstract

摘要：

利用切向旋流管状燃烧机理实验台，结合光学诊断与反应动力学分析，系统研究了CH₄、CO和H₂三种典型燃料掺氨富燃条件下NO _x 排放特性及生成机理。实验结果表明，相比于掺混甲烷，CO的引入能够更好地降低吹熄极限和托举临界值，改善火焰稳定性。然而，活性燃料的掺混燃烧导致NO _x 排放呈数量级增加，尤其在CO/NH₃混燃体系，掺氨比0.6时NO _x 排放高于4500 （体积分数×10^-6，@3.5%O₂），远超CH₄和H₂混燃体系。OH^*和NH₂^*化学自发光以及N主要转化路径的动力学分析表明，富燃条件下，NO _x 生成主要来源于NH _i 路径，OH和NH _i 自由基在NO生成与消耗中起枢纽作用，CO掺氨燃烧体系中，高OH浓度增强了NH _i 自由基的氧化，进而导致NO _x 排放高；同时不同燃料掺混条件下氨脱氢反应及NH _i 还原反应的差异同样影响氮的转化路径。

关键词: 活性燃料掺氨, 燃烧稳定性, NO _x 生成机制, 化学自发光, 反应动力学

Abstract:

Ammonia combustion suffers from high NO _x emissions and poor flame stability, while rich co-firing with active fuels combined with staged combustion offers a promising mitigation strategy. However, the NO _x formation characteristics and interactions between nitrogen-containing intermediates and active fuels underdifferent fuel-specific ammonia-rich conditions remain unclear. Here, a tangential swirl tubular combustor,coupled with optical diagnostics and reaction kinetics analysis, was used to systematically investigate NO _x emissions and formation mechanisms for CH₄, CO, and H₂ co-firing with ammonia. Results show that COaddition lowers the blow-off limit and lift-off height, enhancing flame stability, but active fuel co-firingsignificantly increases NOx emissions, with the CO/NH₃ system showing the highest levels. Specifically, NO _x emission exceeded 4500 (volume fraction×10^-6, @3.5%O₂) when the ammonia blending ratio (E_NH3) was 0.6.OH and NH _i radicals play pivotal roles in NO formation and consumption, with high OH concentrations inCO/NH₃ promoting NH _i oxidation and elevated NO _x emissions, while variations in ammonia dehydrogenationand NH _i reduction across different fuels further influence nitrogen transformation pathways.

Key words: active fuel/ammonia co-combustion, flame stability, NO _x formation mechanism, chemiluminescence, reaction kinetics

中图分类号:

TK16

杨远平, 马佳琪, 司桐, 王翔, 李水清. 不同特征燃料宽范围掺氨富燃污染物排放特性及动力学分析[J]. 化工学报, DOI: 10.11949/0438-1157.20251092.

Yuanping YANG, Jiaqi MA, Tong SI, Xiang WANG, Shuiqing LI. Impact of fuel properties on pollutant emissions and reaction Kinetics in ammonia-blended fuel-rich combustion[J]. CIESC Journal, DOI: 10.11949/0438-1157.20251092.

图/表 12

图1 切向旋流管状燃烧器及其光学诊断与烟气采样系统示意图

Fig.1 Schematic diagram of the tangential swirl tubular burner and optical diagnostics and exhaust gas sampling system

表1 CH4/NH3/Air燃烧体系流量参数设置

Table 1 Flow parameters of CH4/NH3/Air flame with varied ENH3

E_NH3	V_NH3(L/min)	V_CH4(L/min)	V_air(L/min)
0.0	0.00	1.68	14.55
0.2	0.85	1.34	14.36
0.4	1.70	1.01	14.26
0.6	2.55	0.67	14.08
0.8	3.39	0.34	13.95
1.0	4.24	0.00	13.77

图2 掺氨燃烧化学反应器网络（CRN）模型

Fig.2 Chemical reactor network representing the ammonia blending swirl combustion

图3 不同机理计算获得的模拟值与NO x 测量值对比结果

Fig.3 Comparison of NO x predictions from various kinetic mechanisms with experimental data

图4 不同特征燃料掺氨燃烧稳燃极限(P=1.0 kW)

Fig.4 Stability limits of ammonia blending for different fuel types at P=1.0 kW

图5 掺氨比0.8下不同特征燃料掺氨燃烧火焰形貌

Fig.5 The flame morphologies in various fuel blending combustion under typical operating conditions, ENH3=0.8

图6 纯氨(a)及甲烷/氨掺混燃烧(b)体系NO x 排放特性

Fig.6 NO x emissions of (a) pure ammonia and (b) ammonia/methane co-combustion flame

图7 富燃条件下不同特征燃料掺氨燃烧NO x 排放特性，(a) ENH3=0.6, (b) ENH3=0.8注:ENH3=0.6(a) and 0.8(b)

Fig.7 NO x emission characteristics of ammonia co-combustion with different representative fuels under fuel-rich conditions,

图8 不同掺混燃料燃烧过程OH*（左）和NH2*（右）化学自发光信号的Abel变换与时均图像，ENH3=0.8注:blending combustion under typical operating conditions. ENH3=0.8

Fig.8 Abel-transformed and time-averaged images of OH* (left) and NH2* (right) chemiluminescence signals in various fuel

图9 不同掺混燃料OH*和NH2*归一化信号强度随当量比变化特性注:different fuel blended

Fig.9 Variations of the normalized plane-integrated time-averaged OH*and NH2* chemiluminescence signals intensities with

图10 不同燃料掺氨燃烧体系自由基含量随当量比的变化

Fig.10 Radical concentrations as a function of equivalence ratio in ammonia-fuel blended combustion systems

图11 CH4/CO/H2掺氨燃料燃烧主火焰区域NO反应路径（箭头宽度反映特定反应路径的相对重要性）注:arrows reflects the relative importance of a specific reaction pathway)

Fig.11 Reaction pathways of NO in the main flame region during combustion of CH4/CO/H2–NH3 blended fuels (the width of

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