Experimental study on co-firing characteristics of ammonia with pulverized coal in a staged combustion drop tube furnace

Tan, Jiaxin; He, Yong; Zhu, Runfan; Zhu, Yanqun; Wang, Zhihua

doi:10.1016/j.proci.2022.07.032

Cited by 53 publications

(6 citation statements)

References 16 publications

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“…This implies that the excess air ratio is inversely proportional to the equivalence ratio in eq . The excess air ratio or equivalence ratio value would influence the burning efficiency, flame temperature, and combustion products of a fuel sample .…”

Section: Results and Discussionmentioning

confidence: 99%

“…This implies that the excess air ratio is inversely proportional to the equivalence ratio in eq 5 . 68 The excess air ratio or equivalence ratio value would influence the burning efficiency, flame temperature, and combustion products of a fuel sample. 69 The equivalence ratio was observed to increase when the engine speed was increased under a constant engine torque in Figure 5 .…”

Section: Results and Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Engine Performance of High-Acid Oil-Biodiesel through Supercritical Transesterification

Lin,

Lin

2024

ACS Omega

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Relatively cheaper high-acid oil was used to make biodiesel through supercritical methanol transesterification, where high FFA contents in feedstock might conversely enhance the reaction extent. A direct-injection diesel engine and a dynamometer were used to analyze the engine characteristics of the high-acid oilbiodiesel. The experimental results show that the biodiesel made in this study had adequate fuel properties. This present biodiesel from high-acid oil was found to bear a lower heating value and equivalence ratio, with higher exhaust gas temperature, brake-specific fuel consumption (bsfc), and excess air ratio, than super-low sulfur diesel (SLSD). The biodiesel appeared to have larger-sized carbon residue left after the burning process in comparison with that of SLSD. The higher engine speed resulted in higher exhaust gas temperature and equivalence ratio, while lower bsfc, excess air ratio, was observed for the biodiesel. Supercritical methanol transesterification has been successfully proven to convert those low-cost feedstocks to renewable biodiesel products which own competitive engine performance in this study.

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Section: Results and Discussionmentioning

confidence: 99%

Section: Results and Discussionmentioning

confidence: 99%

Engine Performance of High-Acid Oil-Biodiesel through Supercritical Transesterification

Lin,

Lin

2024

ACS Omega

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“…The reason for this was that ammonia rapidly burned under the effect of high-temperature preheating, so the coal particles were preheated by the heat released by ammonia combustion. The release rate of volatile components in the coal was accelerated and the local gas equivalence ratio around the coal particles was also increased . The coal particles burned while being preheated, and they were enveloped by the free radicals and volatile gas which formed by pulverized coal cracking and ammonia decomposition, so the flue gas around the coal particles quickly reached the coal ignition temperature.…”

Section: Resultsmentioning

confidence: 99%

“…The release rate of volatile components in the coal was accelerated and the local gas equivalence ratio around the coal particles was also increased. 20 The coal particles burned while being preheated, and they were enveloped by the free radicals and volatile gas which formed by pulverized coal cracking and ammonia decomposition, so the flue gas around the coal particles quickly reached the coal ignition temperature. When the concentration of coal was lower, each individual coal particle received more heat which was released by ammonia combustion, and the heating rate of coal particles was higher.…”

Section: Resultsmentioning

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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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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“…17,18 However, the combustion characteristics and the side effects associated with the lower NO x control method for coal and ammonia co-combustion with high ammonia blending ratios still require further understanding and consensus. Different patterns of the variation in the unburned carbon contents, such as increasing, 19 decreasing, 9 or first decreasing and then increasing, 20 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, 21 particulate matter, 22 unburnt ammonia, 23 and CO 24 during coal and ammonia co-combustion also needs to be emphasized when regulating NO x emissions.…”

Section: Introductionmentioning

confidence: 88%

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 on co-firing characteristics of ammonia with pulverized coal in a staged combustion drop tube furnace

Cited by 53 publications

References 16 publications

Engine Performance of High-Acid Oil-Biodiesel through Supercritical Transesterification

Engine Performance of High-Acid Oil-Biodiesel through Supercritical Transesterification

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

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