Behavior of nitrogen oxides in a lab-scale coal ammonia co-firing system

Lee, EunSong; Keel, Sang-In; Kim, Min-Su; Jegal, Hyunwook; Yun, Jae-Ho; Hwa, Jun; Baek, Sehyun; Lee, Jongmin; Jeon, MinKyu

doi:10.1016/j.joei.2023.101174

Cited by 8 publications

(3 citation statements)

References 31 publications

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“…Studies have shown that the ammonia mixing ratio, ammonia injection method and location, combustion temperature, oxygen concentration, and gas flow rate are the main influencing factors affecting the combustion characteristics of coal and ammonia gas–solid fuel. 9 − 11 The reduction of CO 2 emissions shows a good linear relationship with the mixing ratio of ammonia, while NO x emissions show a linear increasing trend with the amount of ammonia addition. 12 , 13 When the mixing ratio of ammonia is below 20%, it is possible to achieve NO x emissions lower than or comparable to those of pure coal combustion.…”

Section: Introductionmentioning

confidence: 95%

“…Xia and Hiraoka , found that the flame propagation speed of coal and ammonia cocombustion is three times faster than pure coal combustion and twice as fast as pure ammonia combustion, so as to a certain extent, the problem of slow propagation of ammonia combustion flame can be solved. Studies have shown that the ammonia mixing ratio, ammonia injection method and location, combustion temperature, oxygen concentration, and gas flow rate are the main influencing factors affecting the combustion characteristics of coal and ammonia gas–solid fuel. − The reduction of CO 2 emissions shows a good linear relationship with the mixing ratio of ammonia, while NO x emissions show a linear increasing trend with the amount of ammonia addition. , When the mixing ratio of ammonia is below 20%, it is possible to achieve NO x emissions lower than or comparable to those of pure coal combustion. By adjusting the ammonia injection position and implementing air staged combustion, even lower NO x emissions can be achieved.…”

Section: Introductionmentioning

confidence: 99%

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Experimental Study on Flame Chemical Composition of Coal and Ammonia Gas–Solid Jet in Flat Flame Burner

Cui,

Niu,

et al. 2024

ACS Omega

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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 NO x per unit mass of coal ammonia mixture increased with the increase of pulverized coal concentration. The NO x production amount first increased and then decreased with the increase of pulverized coal concentration, and the amount of N 2 O and NO 2 decreased rapidly with the increase of HAB. The proportion of NO x in NO exceeded 94%, which was conducive to achieving low nitrogen combustion of coal and ammonia gas−solid fuel. In general, the O 2 concentration in the ammonia coal jet flame decreased, the flue gas temperature, and NO x 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 N 2 and NH 3 ).

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Section: Introductionmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Experimental Study on Flame Chemical Composition of Coal and Ammonia Gas–Solid Jet in Flat Flame Burner

Cui,

Niu,

et al. 2024

ACS Omega

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“…Different patterns of the variation in the unburned carbon contents, such as increasing, decreasing, or first decreasing and then increasing, were found in the experiments of coal-ammonia co-combustion with the increase of ammonia blending ratio. In addition, controlling the emission of H 2 S, particulate matter, unburnt ammonia, and CO during coal and ammonia co-combustion also needs to be emphasized when regulating NO x emissions.…”

Section: Introductionmentioning

confidence: 99%

Ignition Characteristics and Interaction of Coal and Ammonia Co-Combustion on a Diffusion-Flamelet-Based Hencken Burner

Yang,

Zhou,

et al. 2024

Energy Fuels

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Co-combustion of coal and ammonia presents an effective strategy to gradually reduce the share of coal-fired power generation and, thereby, achieve CO 2 reduction. In this work, the ignition characteristics and interaction of coal and ammonia cocombustion with varying ammonia blending ratios (0−100%) under different oxygen concentrations (5%−30%) were investigated on a diffusion-flamelet-based Hencken burner. The flame morphologies of coal and ammonia co-combustion under different operating conditions were captured through the co-combustion flame images. And the flame radial intensity profiles at the cross sections of the ignition positions exhibited a bimodal distribution at 20% and 30% O 2 concentrations with the addition of ammonia, which were not observed at 5% and 10% O 2 concentrations or in pure coal combustion scenarios. Correspondingly, the trend in the flame diameter of coal and ammonia co-combustion with the increase of ammonia blending ratio shifted from initially increasing and then decreasing at 5% and 10% O 2 concentrations to a monotonically increasing one at 20% and 30% O 2 concentrations. Furthermore, the chemiluminescence spectrum of coal and ammonia co-combustion was measured to analyze the evolution of the radicals at different ammonia blending ratios, and the NH* and OH* radical signals were used to correlate the intensity of the gas-phase reaction of ammonia and coal volatile matter combustion. It was found that the interaction between ammonia and coal became more pronounced at higher oxygen concentrations. Notably, the NH*/OH* ratio at the outlet of the central fuel tube was strongly correlated with the ignition delay distance of coal and ammonia co-combustion. Finally, the variation of the coal particle temperatures during the ignition stage was analyzed to elucidate the interaction of the co-combustion process. In most cases, the addition of ammonia led to an increase in the maximum temperature of the coal particles. This effect was primarily influenced by the particle number density (PND) of the pulverized coal and the distribution of the thermal input between the coal and ammonia.

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Experimental study of NH3 and coal Co-firing in a CFB and its nitrogen conversion

Li,

Cheng,

Zhao

et al. 2024

Energy

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Behavior of nitrogen oxides in a lab-scale coal ammonia co-firing system

Cited by 8 publications

References 31 publications

Experimental Study on Flame Chemical Composition of Coal and Ammonia Gas–Solid Jet in Flat Flame Burner

Experimental Study on Flame Chemical Composition of Coal and Ammonia Gas–Solid Jet in Flat Flame Burner

Ignition Characteristics and Interaction of Coal and Ammonia Co-Combustion on a Diffusion-Flamelet-Based Hencken Burner

Experimental study of NH3 and coal Co-firing in a CFB and its nitrogen conversion

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