Physicochemical Properties and Formation Mechanism of Soot in the MILD–OCC Combustion Flame
Publication: Journal of Energy Engineering
Volume 146, Issue 4
Abstract
Coal and methane were mixed and burned in the moderate and intensive low oxygen dilution–oxy coal combustion (MILD–OCC) mode, flame temperature was measured at different flame locations with a rapid insert thermocouple, and soot volume fraction was obtained by thermophoretic particle densitometry (TPD). The distribution characteristics of soot in flame were obtained by combining the concentration of soot by the filter weighing method. Soot samples were collected at specific locations in the flame and analyzed with gas chromatography–mass spectrometry (GC-MS) as well as transmission electron microscopy (TEM). The results showed that the flame temperature rose first and then decreased in the radial direction, while soot mass concentration dropped and then increased in general. As to morphology of soot particles, it exhibited spherical particles separately in the lower part of flame and chain-like structures in the upper. Alkanes, olefins, phenols, furans, and aromatic compounds were determined as the main components of soot by the detection of GC-MS. The process of soot formation in the MILD–OCC flame can be speculated as coal pyrolyzes and burns at high temperature and gas precursors initiate nucleation then agglomerate and oxidize to form soot particles.
Get full access to this article
View all available purchase options and get full access to this article.
Data Availability Statement
Some or all data, models, or code generated or used during the study are available from the corresponding author by request.
Acknowledgments
This work was supported by the National Natural Science Foundation of China (Grant No. 51761125011). We are also grateful to the State Key Laboratory of Coal Use Efficiency and Green Chemicals for GC-MS detection.
References
Bradley, D., and A. G. Entwistle. 1961. “Determination of the emissivity, for total radiation, of small diameter Platinum-10% rhodium wires in the temperature range 600-1450°C mild combustion.” Br. J. Appl. Phys. 12: 708–711.
Cavaliere, A., and M. de Joannon. 2006. “Mild combustion.” Prog. Energy Combust. Sci. 30 (4): 329–366. https://doi.org/10.1016/j.pecs.2004.02.003.
Chen, L., S. Z. Yong, and A. F. Ghoniem. 2012. “Oxy-fuel combustion of pulverized coal: Characterization, fundamentals, stabilization and CFD modeling.” Prog. Energy Combust. Sci. 38 (2): 156–214. https://doi.org/10.1016/j.pecs.2011.09.003.
Cheng, Z. 2010. “Study on the emission characteristic of polycyclic aromatic hydrocarbons from coal pyrolysis.” [In Chinese.] Master’s thesis, College of Chemistry and Chemical Engineering, Taiyuan Univ. of Technology.
Cole, J. A., J. D. Bittner, J. P. Longwell, and J. B. Howard. 1984. “Formation mechanisms of aromatic compounds in aliphatic flames.” Combust. Flame 56 (1): 51–70. https://doi.org/10.1016/0010-2180(84)90005-1.
Deng, Z., and Y. Q. Cheng. 2018. “Design of on-line smoke concentration monitoring system based on filter membrane weighing method.” Mod. Electron. Tech. 41 (11): 144–148.
Dobbins, R. A. 2007. “Hydrocarbon nanoparticles formed in flames and diesel engines.” Aerosol Sci. Technol. 41 (5): 485–496. https://doi.org/10.1080/02786820701225820.
Feng, L. L., Y. X. Wu, K. L. Xu, Y. Zhang, and M. Zhang. 2019. “Coal-derived soot behaviors in and atmospheres, studied through a 1-D transient coal combustion model.” Energy Fuels 33 (4): 3620–3629. https://doi.org/10.1021/acs.energyfuels.9b00310.
Frenklach, M., W. C. Gardiner, S. E. Stein, D. W. Clary, and T. Yuan. 1986. “Mechanism of soot formation in acetylene-oxygen mixtures.” Combust. Sci. Technol. 50 (1–3): 79–115. https://doi.org/10.1080/00102208608923927.
Gao, Q., S. Q. Li, Z. Diego, K. Reinhold, and Q. Yao. 2019. “Laser-induced incandescence (LII) diagnostics on the soot formation in the early stage of pulverized coal combustion.” [In Chinese.] J. Eng. Thermophys. 6 (40): 1433–1438.
Ju, H. L., X. B. Cheng, L. Chen, and R. H. Huang. 2011. “Soot particle formation process and size distribution characteristics in cylinder of diesel engine.” [In Chinese.] Chin. Internal Combust. Engine Eng. 32 (6): 18–24.
Li, P. F., J. C. Mi, B. B. Dally, F. F. Wang, L. Wang, Z. H. Liu, S. Chen, and C. G. Zheng. 2011. “Progress and recent trend in MILD combustion.” Sci. China Technol. Sci. 54 (2): 255–269. https://doi.org/10.1007/s11431-010-4257-0.
Liu, J. X., X. M. Jiang, J. Shen, and H. Zhang. 2015. “Influences of particle size, ultraviolet irradiation and pyrolysis temperature on stable free radicals in coal.” Powder Technol. 272 (3): 64–74. https://doi.org/10.1016/j.powtec.2014.11.017.
Lu, J. Y., and Q. L. Weng. 2011. “Distribution characteristics of gas temperature and soot fraction volume in ethylene/air inverse diffusion flame.” [In Chinese.] Acta Chim. Sin. 69 (8): 1011–1016.
Matti Maricq, M. 2011. “Physical and chemical comparison of soot in hydrocarbon and biodiesel fuel diffusion flames: A study of model and commercial fuel.” Combust. Flame 158 (1): 105–116. https://doi.org/10.1016/j.combustflame.2010.07.022.
Richter, H., S. Granata, W. H. Green, and J. B. Howard. 2005. “Detailed modeling of PAH and soot formation in a laminar premixed benzene/oxygen/argon low-pressure flame.” Proc. Combust. Inst. 30 (1): 1397–1405. https://doi.org/10.1016/j.proci.2004.08.088.
Richter, H., and J. B. Howard. 2000. “Formation of polycyclic aromatic hydrocarbons and their growth to soot—A review of chemical reaction pathways” Prog. Energy Combust. Sci. 26 (4–6): 565–608. https://doi.org/10.1016/S0360-1285(00)00009-5.
Shi, X. B. 2013. “Research on soot-release characteristics and mechanism during biomass burning.” [In Chinese.] Master’s thesis, Dept. of Environmental Science and Engineering, North China Electric Power Univ.
Toftegaard, B. M., J. Brix, P. A. Jensen, P. Glarborg, and A. D. Jense. 2010. “Oxy-fuel combustion of solid fuels.” Prog. Energy Combust. Sci. 36 (5): 581–625. https://doi.org/10.1016/j.pecs.2010.02.001.
Wang, H., and M. Frenklach. 1997. “A detailed kinetic modeling study of aromatics formation in laminar premixed acetylene and ethylene flames.” Combust. Flame 110 (1–2): 173–221. https://doi.org/10.1016/S0010-2180(97)00068-0.
Wang, X. W. 2015. “Study on evolutions of physicochemical characteristics for soot particles generated from methane flames.” [In Chinese.] Ph.D. thesis, College of Mechanical Engineering, Tianjin Univ.
Wünning, J. A., and J. G. Wünning. 1997. “Flameless oxidation to reduce thermal no-formation.” Prog. Energy Combust. Sci. 23 (1): 81–94. https://doi.org/10.1016/S0360-1285(97)00006-3.
Xie, K. C. 2002. Coal structure and its reactivity, 210–215. [In Chinese.] Beijing: Science Press.
Xu, K. L., Y. X. Wu, H. S. Shen, and H. Zhang. 2017a. “Soot formation and its radiative heat transfer in coal flames: Model development and implementation with FLUENT.” [In Chinese.] Proc. CSEE 37 (20): 5961–5968.
Xu, K. L., Y. X. Wu, H. S. Shen, Q. Zhang, and H. Zhang. 2017b. “Predictions of soot formation and its effect on the flame temperature of a pulverized coal-air turbulent air.” Fuel 194 (Apr): 297–305. https://doi.org/10.1016/j.fuel.2017.01.032.
Yin, C. G., and J. Y. Yan. 2016. “Oxy-fuel combustion of pulverized fuels: Combustion fundamentals and modeling.” Appl. Energy 162 (1): 742–762. https://doi.org/10.1016/j.apenergy.2015.10.149.
Yu, J. S. 2000. Coal chemistry, 172–177. [In Chinese.] Beijing: Metallurgical Industry Press.
Information & Authors
Information
Published In
Journal of Energy Engineering
Volume 146 • Issue 4 • August 2020
Copyright
©2020 American Society of Civil Engineers.
History
Received: Oct 12, 2019
Accepted: Feb 12, 2020
Published online: May 6, 2020
Published in print: Aug 1, 2020
Discussion open until: Oct 6, 2020
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.