Co-firing characteristics and fuel-N transformation of ammonia/pulverized coal binary fuel

Chen, Chen-Lin; Wang, Zhihua; Zhu, Runfan; Tan, Jiaxin; He, Yong; Cen, Kefa

doi:10.1016/j.fuel.2022.126857

Cited by 31 publications

(8 citation statements)

References 24 publications

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“…This is consistent with the current research findings. 8 As can be clearly seen in Figure 3b, as the temperature rose, the burnout time of coal decreased steadily. The burnout time of coal decreased by nearly 40% when the temperature increased from 900 to 1300 °C.…”

Section: Coal Combustion Kinetics Experiments Undermentioning

confidence: 80%

“…The rate of coal combustion rose as the temperature increased in both coal combustion and coal/NH 3 cocombustion processes. This is consistent with the current research findings . As can be clearly seen in Figure b, as the temperature rose, the burnout time of coal decreased steadily.…”

Section: Resultsmentioning

confidence: 99%

“…In recent years, some researchers have studied coal/NH 3 cocombustion characteristics. − Zhang et al simulated the effect of changing the NH 3 cocombustion ratios on the unburned carbon content in fly ash during coal/NH 3 cocombustion via computational fluid dynamics (CFD). They found that as the NH 3 cocombustion ratios decreased to less than 10%, it is beneficial for coal combustion, and the unburned carbon emission is reduced.…”

Section: Introductionmentioning

confidence: 99%

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The Influence of NH₃ on Coal Combustion Kinetics during Coal/NH₃ Cocombustion: Experiments and ReaxFF MD Simulations

Hong,

Yuan,

Wang

2024

Energy Fuels

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To reduce CO 2 emissions from coal-fired plants, coal/NH 3 cocombustion has received widespread attention. In this work, the influence of NH 3 on coal combustion kinetics during coal/NH 3 cocombustion was studied by constant temperature thermogravimetric experiment and reactive molecular dynamics (ReaxFF MD). The experimental results show that coal combustion is inhibited during coal/NH 3 cocombustion. The weight loss of coal during coal/NH 3 cocombustion was always slower than that during pure coal combustion at all temperatures, and the burn out time of coal increases by 20−30s. The higher the NH 3 cofiring ratio, the slower the weight loss rate of coal. When the NH 3 cofiring ratio increases from 0 to 60%, the burnout time of coal increases by about 25%. The higher the carbon content in coal, the more obvious is the inhibition effect of NH 3 on coal combustion. The inhibitory mechanism of NH 3 on coal was then studied by ReaxFF MD. It is found that the combustion of coal during coal/NH 3 cocombustion is inhibited mainly because NH 3 will compete with coal for O 2 . Compared to pure coal combustion and pure NH 3 combustion, the transfer of O to nitrogen oxides increases by about 1.5 times while the transfer of O to carbon oxides decreases by about 10% during coal/NH 3 cocombustion. This proves that NH 3 dominates in competition for O 2 . Compared with pure coal combustion, the combustion of char, tar, and carbonaceous gas from coal during coal/NH 3 cocombustion is restrained. The decrease rate of H/C ratio of char will slow down. The attachment of O molecules on char will also decrease. These further confirm that NH 3 inhibits coal combustion by competing with coal for O 2 . In this work, the competition mechanism during coal/ NH 3 cocombustion is studied, which is helpful for the development of stable coal combustion and unburned carbon emission reduction technology.

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Section: Coal Combustion Kinetics Experiments Undermentioning

confidence: 80%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The Influence of NH₃ on Coal Combustion Kinetics during Coal/NH₃ Cocombustion: Experiments and ReaxFF MD Simulations

Hong,

Yuan,

Wang

2024

Energy Fuels

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“…Moreover, the nitrogen conversion rate tended to stabilize in the late stages of combustion. This indicated that the addition of ammonia in coal and ammonia gas–solid fuel promoted the conversion of fuel nitrogen to N 2 . The reason for this was ammonia burned before coal combustion under the effect of a high-temperature preheating zone produced by the flat flame burner plane and conditions of excess oxygen, which promote the complete combustion of ammonia to form N 2 .…”

Section: Resultsmentioning

confidence: 99%

“…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%

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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Combustion characteristics on ammonia injection velocity and positions for ammonia co-firing with coal in a pilot-scale circulating fluidized bed combustor

Kim,

Pak,

et al. 2024

Applied Thermal Engineering

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Co-firing characteristics and fuel-N transformation of ammonia/pulverized coal binary fuel

Cited by 31 publications

References 24 publications

The Influence of NH₃ on Coal Combustion Kinetics during Coal/NH₃ Cocombustion: Experiments and ReaxFF MD Simulations

The Influence of NH₃ on Coal Combustion Kinetics during Coal/NH₃ Cocombustion: Experiments and ReaxFF MD Simulations

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

Combustion characteristics on ammonia injection velocity and positions for ammonia co-firing with coal in a pilot-scale circulating fluidized bed combustor

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Co-firing characteristics and fuel-N transformation of ammonia/pulverized coal binary fuel

Cited by 31 publications

References 24 publications

The Influence of NH3 on Coal Combustion Kinetics during Coal/NH3 Cocombustion: Experiments and ReaxFF MD Simulations

The Influence of NH3 on Coal Combustion Kinetics during Coal/NH3 Cocombustion: Experiments and ReaxFF MD Simulations

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

Combustion characteristics on ammonia injection velocity and positions for ammonia co-firing with coal in a pilot-scale circulating fluidized bed combustor

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The Influence of NH₃ on Coal Combustion Kinetics during Coal/NH₃ Cocombustion: Experiments and ReaxFF MD Simulations

The Influence of NH₃ on Coal Combustion Kinetics during Coal/NH₃ Cocombustion: Experiments and ReaxFF MD Simulations