Influence of operating parameters on N2O emission in O2/CO2 combustion with high oxygen concentration in circulating fluidized bed

Li, Shiyuan; Xu, Ming-xin; Jia, Lei; Tan, Li; Qi, Lu

doi:10.1016/j.apenergy.2016.02.054

Cited by 63 publications

(16 citation statements)

References 35 publications

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“…The investment during the last few years has allowed demonstration-scale facilities to be commissioned in which the feasibility of oxy-firing has been proved [4][5][6][7]. Nevertheless, important research efforts are still ongoing concerning its efficiency, emissions and fuel-related issues [8][9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

The role of limestone during fluidized bed oxy-combustion of coal and biomass

et al. 2016

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The interest in bio-CCS technologies is growing due to their potential to reduce CO 2 emission in power generation. Oxy-co-firing in fluidized-bed units is one of the available techniques to develop bio-CCS, offering wide fuel flexibility and low SO 2 and NO x emissions. This paper discusses the results of an experimental campaign carried out in a lab-scale fluidized bed reactor. The work focuses on the influence of limestone when oxy-firing blends of lignite and corn stover. Two different types of limestone with two Ca:S molar ratios were tested, and operational conditions were selected to compare the mechanisms governing desulphurization. Emissions of SO 2 , NO and HCl, together with deposition rates and ash mineralogy are studied in the paper. SO 2 capture increases with the Ca:S ratio and bed temperature, but to a different extent depending on the limestone fragmentation. The amount of NO emitted rises with the Ca:S ratio and the presence of calcined limestone (indirect desulphurization). The HCl concentration in the gas phase is dominated by alkali sulfation. Finally, the conditions for the highest desulphurization efficiency diminished the deposition rates, but increased the risk for chlorine-induced corrosion.

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Section: Introductionmentioning

confidence: 99%

The role of limestone during fluidized bed oxy-combustion of coal and biomass

et al. 2016

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“…Therefore, it can be speculated that there must be an optimal temperature range for char nitrogen to generate N 2 O at the highest level. Li et al also found that NO emission increased as the temperature increased while N 2 O emission decreased in a bubbling fluidized bed in a temperature range of 850–950 °C. A higher excess oxygen ratio caused the increase of both N 2 O and NO emissions.…”

Section: Resultsmentioning

confidence: 93%

Quantum Chemical and Kinetic Studies of N₂O Formation during Interaction between Char(N) and NO: Influence of Oxygen, Active Sites, and Nitrogen Status

Zhao

Niu

et al. 2021

J. Phys. Chem. A

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In order to obtain a deep insight into the N 2 O formation mechanism in a fluidized bed, density functional theory was used to investigate the interaction between char(N) and NO at a molecular level. Three key influencing factors for the formation of N 2 O, namely, active sites, nitrogen status, and oxygen molecules, were taken into study. The geometric structures, electron distribution characteristics, and reaction paths were optimized and calculated. The outer orbital electron properties of char(N) and NO indicate that NO acts as an oxidizer, which tends to abstract electrons from char(N) during the char(N)−NO interaction. A stable N 2 O molecule has a singlet state and presents as a linear molecular structure. The chemisorption on the char surface will weaken the bond energy of NO from 620 to 94.1 kJ/mole, which promotes the catalytic reduction of NO. Active sites on the char surface benefit the reduction of NO to N 2 , rather than N 2 O, which indicates that excessive high temperatures will inhibit the production of N 2 O. The combination of pyridine nitrogen and NO to form N 2 O needs to overcome a much higher energy barrier of 357.4 kJ/mole. The initial chemisorption of oxygen molecules on the char surface will promote the formation of N 2 O by lowering the dissociation energy of N 2 O from the char surface as well as exposing nitrogen to the char surface.

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“…In laminar flames and at the molecular level within turbulent flames, the formation of NO x can be attributed to four distinct chemical kinetic processes: thermal NO x formation, prompt NO x formation, fuel NO x formation, and intermediate N 2 O [30]. The present numerical simulation mainly considers thermal NO x and fast NO x .…”

Section: No X Formation Modelmentioning

confidence: 99%

Experimental and Numerical Study of a Two-Stage Swirl Burner

Lin

Zhang

et al. 2022

Energies

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In this study, we developed the design process and optimization of structural parameters of a new low-NOx burner based on low-NOx combustion technology and the flame stabilization principle. Firstly, on the basis of the two-stage swirl burner, we applied the fuel-graded combustion technology and introduced the central nozzle structure to explore the influence law of graded combustion on NOx emissions. Secondly, on the previously optimized structure, the matching law between the first- and second-stage cyclone blades is analyzed to obtain the optimum structural design solution for heat exchange efficiency and flame front length. Finally, a new conical blunt structure is introduced in conjunction with the flame stabilization principle, and we discuss the effects of different half cone angles on the flame stabilization, flame front length, and heat exchange efficiency of the burner. The research in this paper provides a reliable direction for the design optimization of low-NOx burners.

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Influence of operating parameters on N2O emission in O2/CO2 combustion with high oxygen concentration in circulating fluidized bed

Cited by 63 publications

References 35 publications

The role of limestone during fluidized bed oxy-combustion of coal and biomass

The role of limestone during fluidized bed oxy-combustion of coal and biomass

Quantum Chemical and Kinetic Studies of N₂O Formation during Interaction between Char(N) and NO: Influence of Oxygen, Active Sites, and Nitrogen Status

Experimental and Numerical Study of a Two-Stage Swirl Burner

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Influence of operating parameters on N2O emission in O2/CO2 combustion with high oxygen concentration in circulating fluidized bed

Cited by 63 publications

References 35 publications

The role of limestone during fluidized bed oxy-combustion of coal and biomass

The role of limestone during fluidized bed oxy-combustion of coal and biomass

Quantum Chemical and Kinetic Studies of N2O Formation during Interaction between Char(N) and NO: Influence of Oxygen, Active Sites, and Nitrogen Status

Experimental and Numerical Study of a Two-Stage Swirl Burner

Contact Info

Product

Resources

About

Quantum Chemical and Kinetic Studies of N₂O Formation during Interaction between Char(N) and NO: Influence of Oxygen, Active Sites, and Nitrogen Status