Investigations on the Spatial Distributions of Nox  Formation Routes in the Low-Nox  Combustion Processes with the Internal Flue Gas Recirculation Method

Cheng, Jiaying; Zong, Chao; Bao, Jinrong; Ji, Chenzhen; Zhu, Tong

doi:10.2139/ssrn.4183416

Cited by 1 publication

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“…However, the thresholds of hydrogen enrichments in non-premixed methane low-NOx combustor are still unclear. It is found that prompt NOx is the dominant pathway in non-premixed methane combustion (Cheng et al, 2023). The changes in prompt NOx and the NNH route with hydrogen addition in non-premixed methane low-NOx flames need to be clarified, which are instructive for designing low-NOx combustors.…”

Section: Effects Of Hydrogen Addition On No X Formation In a Nonpremi...mentioning

confidence: 99%

Effects of hydrogen addition on NOx formation in a non-premixed methane low-NOx combustor

CHENG,

ZHU,

DENG

2024

Mechanical Engineering Journal

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Hydrogen is a promising carbon-free fuel, but nitric oxides (NO x ) emissions are significantly increased with higher temperature in hydrogen combustion. Internal flue gas recirculation (IFGR) is one of the most effective NO x reduction techniques in boilers. Previous research has widely reported NO x generation with hydrogen enrichments from a chemical kinetic perspective, however, the NO x formation principles in non-premixed methane/air combustion using IFGR with hydrogen addition are still unclear. This work aims to investigate the effects of hydrogen addition on NO x formation in a non-premixed methane low-NO x combustor using IFGR. The Reynolds-averaged Navier-Stokes (RANS) simulations were conducted on a 5 kW non-premixed combustor with IFGR rate of 17.7%, which generated 11.3 mg/m 3 of total NO x generation in methane combustion. A series of three-dimensional computational fluid dynamics (CFD) simulations with detailed mechanisms was tested on four hydrogen power fractions. The reaction intensities of the main NO x formation pathways were analyzed on reaction rates. The results show that 70% hydrogen power fractions lead to significantly greater NO x concentration to 677.8 mg/m 3 , as high as 60 times of the original concentration. With no additional techniques, the original methane low-NO x combustor is only allowed for hydrogen addition of less than 20% power fraction. The NNH route becomes the second dominant pathway in hydrogen-added flames. Influenced by the growing hydrogen contents, the generation of the NNH route is largely generated from 2 mg/m 3 to 65 mg/m 3 . This work connects the hydrogen addition and the NO x formation pathways in non-premixed methane combustion, and highlights the importance of eliminating thermal NO x and the NNH route to achieve low-NO x combustion rather than sole NO x suppression method, which can provide a reference for designing low-NO x techniques.

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Section: Effects Of Hydrogen Addition On No X Formation In a Nonpremi...mentioning

confidence: 99%

Effects of hydrogen addition on NOx formation in a non-premixed methane low-NOx combustor

CHENG,

ZHU,

DENG

2024

Mechanical Engineering Journal

View full text Add to dashboard Cite

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Investigations on the Spatial Distributions of Nox Formation Routes in the Low-Nox Combustion Processes with the Internal Flue Gas Recirculation Method

Cited by 1 publication

References 0 publications

Effects of hydrogen addition on NO<i><sub>x</sub></i> formation in a non-premixed methane low-NO<i><sub>x</sub></i> combustor

Effects of hydrogen addition on NO<i><sub>x</sub></i> formation in a non-premixed methane low-NO<i><sub>x</sub></i> combustor

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