THERMAL SCIENCE

International Scientific Journal

Authors of this Paper

External Links

Guangya Wang

,

Yifei Huang

,

Hongtao Kao

NUMERICAL SIMULATION OF PULVERIZED COAL COMBUSTION IN A ROTARY KILN UNDER O2/CO2 ATMOSPHERE

ABSTRACT
The cement industry is the second largest source of global man-made CO2 emissions after the power industry, and the adoption of O2/CO2 combustion technology for cement kilns is of great significance in reducing CO2 emissions. In this paper, the effects of pulverized coal mixed air combustion and pulverized coal mixed O2/CO2 combustion on the velocity field, temperature field, CO2 and NOx concentration distribution in rotary kiln were investigated by CFD technique. The results showed that there is no difference in the velocity distribution between the two atmospheres, and the speed difference between the primary and secondary air creates a re-circulation zone near the burner. The O2/CO2 atmosphere combustion decreased the maximum temperature, but improved the uniformity of the temperature field. The pulverized coal burnout rate under O2/CO2 atmosphere decreased by 3.55% compared to O2/N2 atmosphere. The mole fraction of CO2 at the rotary kiln outlet is 0.08 and 0.93 for O2/N2 and O2/CO2 combustion atmospheres, respectively. It is easier to achieve CO2 aggregation and capture under O2/CO2 atmosphere than under O2/N2. The NOx concentration at O2/CO2 is approximately one half of that at O2/N2, which can save the investment on denitrification equipment. The simulation results reasonably agree with the measured data. The findings of this work will provide a reference for the generalization and application of the O2/CO2 flue gas cycle calcinating cement technology.
KEYWORDS
Cement rotary kiln, O2/CO2 combustion, CO2 emission reduction, numerical simulation
PAPER SUBMITTED: 2023-02-05
PAPER REVISED: 2023-04-20
PAPER ACCEPTED: 2023-04-27
PUBLISHED ONLINE: 2023-06-11
DOI REFERENCE: https://doi.org/10.2298/TSCI230205126W
CITATION EXPORT: view in browser or download as text file
THERMAL SCIENCE YEAR 2023, VOLUME 27, ISSUE Issue 6, PAGES [4935 - 4945]
REFERENCES
  1. Liu, Y., Kao, H. T., Numerical Simulation of Urea Based SNCR Process in a Trinal-Sprayed Precalciner, Journal of Renewable Materials, 9 (2021), 2, pp. 269-294
  2. Zhang, L. Y., et al., Numerical Simulation of Oxy-fuel Combustion with Different O2/CO2 fractions in Large Cement Precalciner, Energy & Fuels, 34 (2020), 4, pp. 4949-4957
  3. Liu, Y., et al., A Study on Coal Combustion and Desulfurizaion Chara Cteristics in Atmosphere Containing O2/CO2, Proceedings of the Chinese Society of Electrical Engineering, 24 (2004), 8, pp. 224-228
  4. Kabir, G., Madugu, A. I., Assessment of environmental impact on air quality by cement industry and mitigating measures: a case study, Environmental Monitoring and Assessment, 160 (2010), 1-4, pp. 91-99
  5. Chen, C. M., et al., Experimental study on NOx emission from coal combustion under O2/CO2 atmosphere, Journal of Southeast University, 35 (2005), 5, pp. 738-741
  6. Suda, T., et al., Effect of carbon dioxide on flame propagation of pulverized coal clouds in CO2/O-2 combustion, Fuel, 86 (2007), 12-13, pp. 2008-2015
  7. Li, D. B., et al., Coal Combustion Characteristics and Kinetics Analysis in O_2/CO_2 Atmosphere, Journal of Combustion Science and Technology, 24 (2018), 3, pp. 223-231
  8. Chui, E., et al., Modeling of oxy-fuel combustion for a western Canadian sub-bituminous coal, Fuel, 82 (2003), 10, pp. 1201-1210
  9. Granados, D. A., et al., Effect of flue gas recirculation during oxy-fuel combustion in a rotary cement kiln, Energy, 64 (2014), pp. 615-625
  10. Ditaranto, M., Bakken, J., Study of a full scale oxy-fuel cement rotary kiln, International Journal of Greenhouse Gas Control, 83 (2019), pp. 166-175
  11. Telesca, A., et al., Low-CO2 Cements from Fluidized Bed Process Wastes and Other Industrial By-Products, Combustion Science and Technology, 188 (2016), 4-5, pp. 492-503
  12. Granados, D. A., et al., Oxy-fuel combustion as an alternative for increasing lime production in rotary kilns, Applied Energy, 158 (2015), 4, pp. 107-117
  13. Rybdylova, O., et al., A model for droplet heating and its implementation into ANSYS Fluent, International Communications in Heat and Mass Transfer, 76 (2016), pp. 265-270
  14. Wang, X., et al., Prediction of falling film evaporation on the AP1000 passive containment cooling system using ANSYS FLUENT code, Annals of Nuclear Energy, 95 (2016), pp. 168-175
  15. Branco, J., et al., Experimental and numerical investigation of turbulent diffusion flames in a laboratory combustor with a slot burner, Fuel, 175 (2016), pp. 182-190
  16. Rahmanian, B., et al., Investigation of pollutant reduction by simulation of turbulent non-premixed pulverized coal combustion, Applied Thermal Engineering, 73 (2014), 1, pp. 1222-1235
  17. Gomez, M. A., et al., Numerical simulation of the combustion process of a pellet-drop-feed boiler, Fuel, 184 (2016), pp. 987-999
  18. Mujumdar, K. S., Ranade, V. V., CFD modeling of rotary cement kilns, Asia-Pacific Journal of Chemical Engineering, 3 (2008), 2, pp. 106-118
  19. Kangwanpongpan, T., et al., Prediction of oxy-coal combustion through an optimized weighted sum of gray gases model, Energy, 41 (2012), 1, pp. 244-251
  20. Zhu, G., et al., Study on NOx emissions during the coupling process of preheating-combustion of pulverized coal with multi-air staging, Journal of Cleaner Production, 292 (2021), p. 126012
  21. Pieper, C., et al., Numerical investigation of the impact of coating layers on RDF combustion and clinker properties in rotary cement kilns, Fuel, 283 (2021), p. 118951
  22. Liu, J., et al., Carbon and air pollutant emissions from China's cement industry 1990-2015: trends, evolution of technologies, and drivers, Atmospheric Chemistry and Physics, 21 (2021), 3, pp. 1627-1647
  23. Bhunia, S., et al., Reaction kinetics of coal char in oxy-fuel combustion environment and characterization of reacted char, Energy Sources Part a-Recovery Utilization and Environmental Effects (2021), pp. 1-23
  24. Wang, M., et al., Numerical Simulation of Oxy-coal Combustion in a Rotary Cement Kiln, Applied Thermal Engineering, 103 (2016), pp. 491-500
  25. Huang, Y., et al., Numerical simulation of pulverized coal combustion in rotary kilns with different oxygen concentrations, Energy Sources Part a-Recovery Utilization and Environmental Effects, 44 (2022), 2, pp. 4510-4524
  26. S, X. S., et al., Numerical simulation and reliability verification of pulverized coal combustion in rotary kiln and decomposing furnace under O_2/CO_2 condition, Chinese Journal of Environmental Engineering, 14 (2020), 5, pp. 1311-1319
  27. Glarborg, P., Bentzen, L. L. B., Chemical effects of a high CO2 concentration in oxy-fuel combustion of methane, Energy & Fuels, 22 (2008), 1, pp. 291-296
PDF VERSION [DOWNLOAD]
Numerical simulation of pulverized coal combustion in a rotary kiln under O2/CO2 atmosphere

© 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