Effect of particle size on coal char----NO reaction

Abstract

Surface nitrogen complex formation upon reaction of coal char with NO at 600°C was studied by X-ray photoelectron spectroscopy. Particle size had a noticeable effect on the magnitude of changes, which was observed on the surface of the coal char in the nitrogen functional group. The surface increased its -NO, pyridine-N-oxide, and -NO₂ functional group contents with a decrease in particle size. The chemisorption processes of NO molecules on the char were simulated using the ab initio Hartree–Fock method and density functional theory. Molecular modeling was applied to determine the thermodynamics of the reactions. Mechanisms were proposed to explain the formation of the -NO, pyridine-N-oxide, and -NO₂ functional groups at 600°C.

Keywords

NO reduction / chemisorption / particle size / X-ray photoelectron spectroscopy / density functional theory (DFT)

References

[1] Dimitriou D J, Kandamby N, Lockwood F C. A mathematical modelling technique for gaseous and solid fuel reburning in pulverized coal combustors. Fuel, 2003, 82(15-17): 2107–2114

[2] Tree D R, Clark A W. Advanced reburning measurements of temperature and species in a pulverized coal flame. Fuel, 2000, 79(13): 1687–1695

[3] Hampartsoumian E, Folayan O O, Nimmo W, Gibbs B M. Optimisation of NO_x reduction in advanced coal reburning systems and the effect of coal type. Fuel, 2003, 82(4): 373–384

[4] Li Z Q, Yang L B, Qiu P H, Sun R, Chen L Z, Sun S Z. Experimental study of the combustion efficiency and formation of NO_x in an industrial pulverized coal combustion. International Journal of Energy Research, 2004, 28(5): 511–520

[5] Jiang X M, Zheng C G, Yan C, Liu D C, Qiu J R, Li J B. Physical structure and combustion properties of super fine pulverized coal particle. Fuel, 2002, 81(6): 793–797

[6] Matos M A A, Pereira F J, Ventura J M P. Kinetics of NO reduction by anthracite char in a fluidized bed reactor. Fuel, 1990, 69(11): 1435–1439

[7] Chambrion P, Kyotani T, Tomita A. Role of N-containing surface species on NO reduction by carbon. Energy & Fuels, 1998, 12(2): 416–421

[8] Suzuki T, Kyotani T, Tomita A. Study on the carbon-nitric oxide reaction in the presence of oxygen. Industrial & Engineering Chemistry Research, 1994, 33(11): 2840–2845

[9] Pels J R, Kapteijn F, Moulijn J A, Zhu Q, Thomas K M. Evolution of nitrogen functionalities in carbonaceous materials during pyrolysis. Carbon, 1995, 33(11): 1641–1653

[10] Stanczyk K, Dziembaj R, Piwowarska Z, Witkowski S. Transformation of nitrogen structures in carbonization of model compounds. Carbon, 1995, 33(10): 1383–1392

[11] Kelemen S R, Gorbaty M L, Kwiatek P J. Quantification of nitrogen forms in Argonne premium coals. Energy & Fuels, 1994, 8(4): 896–906

[12] Kozowski M. XPS study of reductively and non-reductively modified coals. Fuel, 2004, 83(3): 259–265

[13] Domazetis G, Raoarun M, James B D, Liesegang J, Pigram P J, Brack N, Glaisher R. Analytical and characterization studies of organic and inorganic species in brown coal. Energy & Fuels, 2006, 20(4): 1556–1564

[14] Chen N, Yang R T. Ab initio molecular orbital calculation on graphite: Selection of molecular system and model chemistry. Carbon, 1998, 36(7, 8): 1061–1070

[15] Zhu A H, Finnerty J, Lu G Q, Yang R T. Opposite roles of O₂ in NO—, N₂O—carbon reactions: an ab-initio study. Journal of Physical Chemistry B, 2001, 105(4): 821–830

[16] Montoya A, Mondragon F, Truong T N. First-principles kineticsof CO desorption from oxygen species on carbonaceous surface. Journal of Physical Chemistry A, 2002, 106(16): 4236–4239

[17] Jiang X M, Zheng C G, Qiu J R, Li J B, Liu D C. Combustion characteristics of super fine pulverized coal particle. Energy & Fuels, 2001, 15(5): 1100–1102

[18] Krishnaswamy S, Bhat S, Gunn R D, Agarwal P K. Low-temperature oxidation of coal: 1. A single-particle reaction-diffusion model. Fuel, 1996, 75(3): 333–343

Acknowledgment

This work was supported by the National Natural Science Foundation of China (Grant No. 50876060).

RIGHTS & PERMISSIONS

2014 Higher Education Press and Springer-Verlag Berlin Heidelberg