The regulation effect of methane and hydrogen on the emission characteristics of ammonia/air combustion in a model combustor
The regulation effect of methane and hydrogen on the emission characteristics of ammonia/air combustion in a model combustor
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DOI：
10.1016/j.ijhydene.2021.03.210
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发表时间：
2021-04
影响因子：
7.2
通讯作者：
Meng Zhang;Zhenhua An;Liang Wang;Xutao Wei;Bieerlan Jianayihan;Jinhua Wang;Zuo-hua Huang;H. Tan
中科院分区：
文献类型：
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作者：
Meng Zhang;Zhenhua An;Liang Wang;Xutao Wei;Bieerlan Jianayihan;Jinhua Wang;Zuo-hua Huang;H. Tan
氨作为燃气轮机的燃料，由于其零碳排放，引起了燃烧界的广泛关注。然而，氨燃烧仍然面临着一些挑战，包括弱燃烧和急剧的NOx排放，阻碍了其应用。结果表明，添加甲烷、氢气等活性燃料可以提高氨/空气火焰的燃烧强度，但同时也会产生NOx排放问题。研究了甲烷和氢气对燃气涡轮机燃烧室中氨/空气火焰排放特性的调节作用。分别采用平面激光诱导荧光（PLIF）技术和傅里叶变换红外（FTIR）技术测量了燃烧室出口处的瞬时OH分布和全局排放。火焰也模拟大涡模拟，以进一步揭示排放物形成的物理和化学过程。结果表明，对于NH3/空气火焰，燃气涡轮机燃烧室的排放特性与计算的一维火焰相似。此外，在当量比（φ）约为1.1时，NOx排放和未燃NH3可同时控制到适当值。NH_3/H_2/空气火焰和NH_3/CH_4/空气火焰中NO和NO_2浓度随φ的变化规律与NH_3/空气火焰相似，峰值均向富燃方向移动。这表明，NH3/空气火焰可以通过添加少量的活性燃料来调节，而不会增加NOx排放水平。当Zf = 0.3时，NH_3/CH_4/空气火焰的NOx和CO排放量明显增大，表明H_2是一种较好的燃烧方式。大涡模拟结果表明，NO和OH自由基之间存在着普遍的正相关关系.与CH 4/空气火焰相比，温度对NOx生成的促进作用是次要的。
Ammonia, made up of 17.8%hydrogen, has attracted a lot of attention in combustion community due to its zero carbon emission as a fuel in gas turbines. However, ammonia combustion still faces some challenges including the weak combustion and sharp NOx emissions which discourage its application. It was demonstrated that the combustion intensity of ammonia/air flame can be enhanced through adding active fuels like methane and hydrogen, while the NOx emission issue will emerge in the meantime. This study investigates regulation effect of methane and hydrogen on the emission characteristics of ammonia/air flame in a gas turbine combustor. The instantaneous OH profile and global emissions at the combustion chamber outlet are measured with Planar Laser Induced Fluorescence (PLIF) technique and the Fourier Transform Infrared (FTIR), respectively. The flames are also simulated by large eddy simulation to further reveal physical and chemical processes of the emissions formation. Results show that for NH3/air flames, the emissions behavior of the gas turbine combustor is similar to the calculated one-dimensional flames. Moreover, the NOx emissions and the unburned NH3can be simultaneously controlled to a proper value at the equivalence ratio (φ) of approximate 1.1. The variation of NO and NO2withφfor NH3/H2/air flames and NH3/CH4/air flames at blending ratio (Zf) of 0.1 are similar to the NH3/air flames, with the peak moving towards rich condition. This indicates that the NH3/air flame can be regulated through adding a small amount of active fuels without increasing the NOx emission level. However, whenZf= 0.3, we observe a clear large NOx emission and CO for NH3/CH4/air flames, indicating H2is a better choice on the emission control. The LES results show that NO and OH radicals exhibit a general positive correlation. And the temperature plays a secondary role in promoting NOx formation comparing with CH4/air flame.