THERMAL SCIENCE

International Scientific Journal

Shilin Yu

,

Zhaomin Lv

,

Yang Miao

,

Xiaohe Xiong

,

Houzhang Tan

EXPERIMENTAL STUDY ON NO HETEROGENEOUS REDUCTION BY CHAR

ABSTRACT
The NO heterogeneous reduction by char is one of the most prominent options to control NOx emissions from coal-fired power plants. Experiments on the char-NO heterogeneous reaction were carried out in an electrically heated fixed-bed reac-tor to investigate the effect of temperature, type of char, pretreatment method, additives and reaction atmosphere on the NO reduction capacity of char. The re-sults showed that temperature plays a crucial role in the NO reduction by differ-ent char. The kinetic analysis showed that char-NO heterogeneous reaction is controlled by chemical kinetic below Tt and by diffusion kinetic above Tt. The value of transition temperature Tt depends on the types of char and ranges from 600°C to 800°C. The synergistic effect of specific surface area, mineral abun-dance and reactivity combine to result in the reduction efficiencies of different char. Oxygen has a promoting effect on the char-NO heterogeneous reaction, and the oxygen content of the promoting peak moves to low oxygen content with in-creasing temperature. At 1050 °C, the denitrification efficiency at 0.25% O2 con-tent is 12.7% higher than that under oxygen-free conditions. At high tempera-tures, the promotion of the char-NO heterogeneous reaction by CO and the inhi-bition of the reaction by CH4 were more obvious.
KEYWORDS
coal char, heterogeneous reduction, NO reduction, synergistic effect, alkali metal
PAPER SUBMITTED: 2021-12-17
PAPER REVISED: 2021-05-30
PAPER ACCEPTED: 2021-06-05
PUBLISHED ONLINE: 2022-10-29
DOI REFERENCE: https://doi.org/10.2298/TSCI2205147Y
CITATION EXPORT: view in browser or download as text file
THERMAL SCIENCE YEAR 2022, VOLUME 26, ISSUE Issue 5, PAGES [4147 - 4156]
REFERENCES
  1. Glarborg, P., et al., Modeling Nitrogen Chemistry in Combustion, Progress in Energy and Combustion Science, 67 (2018), July, pp. 31-68
  2. Fan, L.-S., R. Jadhav, Clean Coal Technologies: OSCAR and CARBONOX Commercial Demonstra-tions, AIChE Journal, 48 (2002), 10, pp. 2115-2123
  3. Shu, Y., et al., An Experimental Study of Heterogeneous NO Reduction by Biomass Reburning, Fuel Processing Technology, 132 (2015), Apr., pp. 111-117
  4. Liu, L., et al., Effect of Calcium on the Absorption of NO on Char Surface: A Density Functional Theo-ry Study, Journal of Fuel Chemistry and Technology, 43 (2015), 12, pp. 1414-1419
  5. Zhang X., X. M., Wu, H., et al., Microscopic Effect Mechanism of Ca on NO Heterogeneous Reduction by Char: A DFT Study, Journal of Fuel Chemistry and Technology, 48 (2020), 2, pp. 163-171
  6. Zhang, J., et al., Modeling NO-Char Reaction at High Temperature, Energy & Fuels, 23 (2009), 5, pp. 2376-2382
  7. Zhu, X., et al., Effect of N-Doping on NO2 Adsorption and Reduction over Activated Carbon: An Exper-imental and Computational Study, Fuel, 258 (2019), Dec., ID 116109
  8. Illan-Gomez, M., et al., NO Reduction by Activated Carbons. 7. Some Mechanistic Aspects of Uncata-lyzed and Catalyzed Reaction, Energy & Fuels, 10 (1996), 1, pp. 158-168
  9. Liu, H., et al., Effect of Mineral Matter on Structure and Dielectric Properties of Chars. Fuel, 222 (2018), June, pp. 370-374
  10. Gupta, H., Fan, L.-S., Reduction of Nitric Oxide from Combustion Flue Gas by Bituminous Coal Char in the Presence of Oxygen, Industrial & Engineering Chemistry Research, 42 (2003), 12, pp. 2536-2543
  11. Zhang, J., et al., Kinetics of NO-Char Reaction at Temperatures of 1073-1573K, Proceedings, 2nd Inter-national Conference on Bioinformatics and Biomedical Engineering, iCBBE 2008, Hulunbeier, China, 2008
  12. Sun, S., et al., Kinetic Analysis of NO-Char Reaction, Korean Journal of Chemical Engineering, 26 (2009), 2, pp. 554-559
  13. Wang, Q., et al., Metal Organic Frameworks-Assisted Fabrication of CuO/Cu2O for Enhanced Selective Catalytic Reduction of NOx by NH3 at Low Temperatures, Journal of Hazardous Materials, 364 (2019), Feb., pp. 499-508
  14. Wang, C. A., et al., Effect of Water Washing on Reactivities and NOx Emission of Zhundong Coals, Journal of the Energy Institute, 89 (2016), 4, pp. 636-647
  15. Illan-Gomez, M. J., et al., NO Reduction by Activated Carbons. 5. Catalytic Effect of Iron. Energy & Fuels, 9 (1995), 3, pp. 540-548
  16. Fan, W., et al., Effect of Preoxidation O2 Concentration on the Reduction Reaction of NO by Char at High Temperature, Industrial & Engineering Chemistry Research, 52 (2013), 18, pp. 6101-6111
  17. Zhao, Z., et al., Catalytic Reduction of NO by Coal Chars Loaded with Ca and Fe in Various Atmos-pheres, Fuel, 81 (2002), 11, pp. 1559-1564
  18. Chan, L., et al., Kinetics of the NO Carbon Reaction at Fluidized Bed Combustor Conditions, Combus-tion and Flame, 52 (1983), 1, pp. 37-45
  19. Brown, T., B. Haynes, Interaction of Carbon Monoxide with Carbon and Carbon Surface Oxides, Energy & Fuels, 6 (1992), 2, pp. 154-159
  20. Yamashita, H., et al., Influence of Char Surface Chemistry on the Reduction of Nitric Oxide with Chars, Energy & Fuels, 7 (1993), 1, pp. 85-89
  21. Abanades, S., et al., Kinetic Investigation of Carbon-Catalyzed Methane Decomposition in a Thermo-gravimetric Solar Reactor, International Journal of Hydrogen Energy, 40 (2015), 34, pp. 10744-10755
  22. Karaismailoglu, M., et al., Hydrogen Production by Catalytic Methane Decomposition over Yttria Doped Nickel Based Catalysts, International Journal of Hydrogen Energy, 44 (2019), 20, pp. 9922-9929
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Experimental study on no heterogeneous reduction by char

© 2024 Society of Thermal Engineers of Serbia. Published by the Vinča Institute of Nuclear Sciences, National Institute of the Republic of Serbia, Belgrade, Serbia. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International licence