Abstract
MILD (moderate or intense low-oxygen dilution) combustion is a promising technology for high efficiency and extremely low-NO X emission during industrial heating, and it is expected to be combined with oxy-fuel combustion for CCS (carbon capture and storage). However, studies related to coal MILD combustion are quite sparse. In this paper, the coal MILD combustion characteristics in O2/N2, O2/CO2, and O2/H2O atmospheres were compared numerically, to offer guidance for combining MILD combustion with oxy-fuel combustion for pulverized coal in our future work. First, a validation of the predictions against the measurements was performed to assess the reliability of the numerical models. Then, coal MILD combustion was modeled in O2/N2, O2/CO2, and O2/H2O atmospheres, respectively, with the validated models. The main emphasis was laid on the temperature distribution, intermediate species conversion, and NO X formation. The results reveal that the present combustion mechanism is capable of modeling coal MILD combustion. Moreover, CO2 is superior to both N2 and H2O in homogenizing the temperature field, except for delayed ignition. Due to the enhanced char gasification reactions by CO2 and H2O, the formations of the intermediates (CO and H2) are promoted. As a consequence, the CO2- and H2O-moderated MILD combustion shows a greater potential on the final NO emission than the N2 moderated case. Because of the differences in NO reduction ability between CO and H2, NO emission in O2/H2O is further lower than that in O2/CO2 atmosphere.
This is a preview of subscription content, log in via an institution to check access.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
References
Cavaliere A, Joannon MD (2004) Mild combustion. Prog Energy Combust Sci 30(4):329–366
Katsuki M, Hasegawa T (1998) The science and technology of combustion in highly preheated air. Symp Combust 27:3135–3146
Wünning JA, Wünning JG (1997) Flameless oxidation to reduce thermal no-formation. Prog Energy Combust Sci 23(1):81–94
Arghode VK, Gupta AK (2010) Effect of flow field for colorless distributed combustion (CDC) for gas turbine combustion. App Energy 87(5):1631–1640
Weber R, Smart JP (2005) On the (MILD) combustion of gaseous, liquid, and solid fuels in high temperature preheated air. Proc Combust Inst 30(2):2623–2629
Kim J, Schnell U (2007) Numerical modelling of mild combustion for coal. Prog Comput Fluid Dyn 7(6):337–346
Schaffel N, Mancini M (2009) Mathematical modeling of MILD combustion of pulverized coal. Combust Flame 156(9):1771–1784
Vascellari M, Cau G (2011) Influence of turbulence–chemical interaction on CFD pulverized coal MILD combustion modeling. Fuel 101(2):90–101
Mei Z, Li P (2013) Influences of reactant injection velocities on moderate or intense low-oxygen dilution coal combustion. Energy Fuels 28(1):369–384
Suda T, Takafuji M (2002) A study of combustion behavior of pulverized coal in high-temperature air. Proc Combust Inst 29(1):503–509
He R, Suda T (2004) Analysis of low NO emission in high temperature air combustion for pulverized coal. Fuel 83(9):1133–1141
Zhang H, Yue G (2007) Development of high temperature air combustion technology in pulverized fossil fuel fired boilers. Proc Combust Inst 31(2):2779–2785
Buhre BJP, Elliott LK (2005) Oxy-fuel combustion technology for coal-fired power generation. Prog Energy Combust Sci 31(4):283–307
Blasiak W, Yang WH (2007) Flameless oxyfuel combustion for fuel consumption and nitrogen oxides emissions reductions and productivity increase. J Energy Inst 80(1):3–11
Stadler H, Ristic D (2009) NOx-emissions from flameless coal combustion in air, Ar/O2 and CO2/O2. Proc Combust Inst 32(2):3131–3138
Li P, Wang F (2014) Moderate or intense low-oxygen dilution oxy-combustion characteristics of light oil and pulverized coal in a pilot-scale furnace. Energy Fuels 28(2):1524–1535
Saha M, Dally BB (2014) Moderate or intense low oxygen dilution (MILD) combustion characteristics of pulverized coal in a self-recuperative furnace. Energy Fuels 28(9):6046–6057
Tu Y, Liu H (2015) Numerical study of combustion characteristics for pulverized coal under oxy-MILD operation. Fuel Process Technol 135:80–90
Mei Z, Mi J (2012) Dimensions of CH4-jet flame in hot O2/CO2 coflow. Energy Fuels 26(6):3257–3266
Seepana S, Jayanti S (2010) Steam-moderated oxy-fuel combustion. Energy Convers Manag 51(10):1981–1988
Dally BB, Shim SH (2010) On the burning of sawdust in a MILD combustion furnace. Energy Fuels 24(6):3462–3470
Acknowledgments
This work was supported by National Natural Science Foundation of China (51276074), State Key Development Program for Basic Research of China (2011CB707301), and Doctoral Fund of Ministry of Education of China (20130142130009).
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2016 Springer Science+Business Media Singapore and Tsinghua University Press
About this paper
Cite this paper
Tu, Y., Kong, F., Su, K., Liu, H., Zheng, C. (2016). Numerical Study of MILD Combustion for Pulverized Coal in O2/N2, O2/CO2, and O2/H2O Atmospheres. In: Yue, G., Li, S. (eds) Clean Coal Technology and Sustainable Development. ISCC 2015. Springer, Singapore. https://doi.org/10.1007/978-981-10-2023-0_21
Download citation
DOI: https://doi.org/10.1007/978-981-10-2023-0_21
Published:
Publisher Name: Springer, Singapore
Print ISBN: 978-981-10-2022-3
Online ISBN: 978-981-10-2023-0
eBook Packages: EnergyEnergy (R0)