Abstract
Oxy-steam combustion is a new oxy-fuel combustion technology which involves fuels burn in pure oxygen, and the high temperature is moderated using either water or steam. In this study, FG and XS char samples were prepared in a horizontal tube furnace at 1073 K under argon atmosphere. The combustion characteristics and kinetic parameters of FG and XS char in O2/H2O atmosphere were studied using non-isothermal thermogravimetric analysis. The results indicated that replacing N2 by H2O caused the improved in the combustion reactivity and performance of FG and XS char with the identical oxygen concentration. The ignition temperature, peak temperature and burnout temperature in O2/H2O atmosphere were lower than those in O2/N2 atmosphere with the identical oxygen concentration. The activation energy values of FG and XS determined by three mode-free methods decreased with the increasing conversion level, and the activation energy of FG char was less than that of XS char at the same conversion. The kinetic mechanism function calculated result based on the combination of the Popescu method and the Coats–Redfern integral method showed the combustion of FG char in O2/H2O atmosphere followed the first-order chemical reaction kinetic.
Similar content being viewed by others
References
IPCC. Summary for policymakers. In: Solomon S, Qin D, Manning M, Chen Z, Marquis M, Averyt KB, Tignor M, Miller HL, editors. Climate change 2007: the physical science basis. Contribution of working group I to the fourth assessment report of the intergovernmental panel on climate change. Cambridge: Cambridge University Press; 2007. p. 2–4.
Edge P, Gharebaghi M, Irons R, Porter R, Porter RTJ, Pourkashanian M, Smithc D, Stephensond P, Williamsa A. Combustion modelling opportunities and challenges for oxy-coal carbon capture technology. Chem Eng Res Des. 2011;89:1470–93.
Chen L, Yong SZ, Ghoniem AF. Oxy-fuel combustion of pulverized coal: characterization, fundamentals, stabilization and CFD modeling. Prog Energy Combust Sci. 2012;38:156–214.
Toftegaard MB, Brix J, Jensen PA, Glarborg P, Jensen AD. Oxy-fuel combustion of solid fuels. Prog Energy Combust Sci. 2010;36:581–625.
Salvador C, Mitrovic M, Kourash K. Novel oxy-steam burner for zero-emission power plants. 2009. http://www.ieaghg.org/docs/oxyfuel/OCC1/Session%206_C/2_NOVEL%20OXY-STEAM%20BURNER%20FOR%20ZERO-EMISSION%20POWER%20PLANTS.pdf.
Salvador C. Modeling design and pilot-scale experiments of CANMET’S advanced oxy-fuel/steam burner. In: International oxy-combustion reserch network 2nd workshop. USA; 25, 26 Jan 2007.
Seepana S, Jayanti S. Steam-moderated oxy-fuel combustion. Energy Convers Manage. 2010;51:1981–8.
Rathnam RK, Elliott LK, Wall TF, Liu Y, Moghtaderi B. Differences in reactivity of pulverised coal in air (O2/N2) and oxy-fuel (O2/CO2) conditions. Fuel Process Technol. 2009;90(6):797–802.
Buhre B, Elliott L, Sheng C, Gupta R, Wall T. Oxy-fuel combustion technology for coal-fired power generation. Prog Energy Combust Sci. 2005;31(4):283–307.
Kuehl D. Effects of water on burning velocity of hydrogen-air flames. ARSJ-AM Rocket Soc J. 1962;32:1724–6.
Babkin V, V’yun A. Effect of water vapor on the normal burning velocity of a methane-air mixture at high pressures. Combust Explo Shock+. 1971;7(3):339–41.
Koroll G, Mulpuru S. The effect of dilution with steam on the burning velocity and structure of premixed hydrogen flames. Symp Int Combust. 1988;21(1):1811–9.
Liu D, MacFarlane R. Laminar burning velocities of hydrogen-air and hydrogen-air steam flames. Combust Flame. 1983;49(1):59–71.
Boushaki T, Dhué Y, Selle L, Ferret B, Poinsot T. Effects of hydrogen and steam addition on laminar burning velocity of methane–air premixed flame: experimental and numerical analysis. Int J Hydrog Energy. 2012;37(11):9412–22.
Mazas A, Fiorina B, Lacoste D, Schuller T. Effects of water vapor addition on the laminar burning velocity of oxygen-enriched methane flames. Combust Flame. 2011;158(12):2428–40.
Gil M, Riaza J, Álvarez L, Pevida C, Pis J, Rubiera F. A study of oxy-coal combustion with steam addition and biomass blending by thermogravimetric analysis. J Therm Anal Calorim. 2011;109(1):49–55.
Yi B, Zhang L, Huang F, Mao Z, Zheng C. Effect of H2O on the combustion characteristics of pulverized coal in O2/CO2 atmosphere. Appl Energy. 2014;132:349–57.
Riaza J, Álvarez L, Gil M, Pevida C, Pis J, Rubiera F. Effect of oxy-fuel combustion with steam addition on coal ignition and burnout in an entrained flow reactor. Energy. 2011;36(8):5314–9.
Hecht ES, Shaddix CR, Geier M, Molina A, Haynes BS. Effect of CO2 and steam gasification reactions on the oxy-combustion of pulverized coal char. Combust Flame. 2012;159(11):3437–47.
Zou C, Zhang L, Cao S, Zheng C. A study of combustion characteristics of pulverized coal in O2/H2O atmosphere. Fuel. 2014;115:312–20.
Zou C, Cai L, Wu D, Liu Y, Liu S, Zheng C. Ignition behaviors of pulverized coal particles in O2/N2 and O2/H2O mixtures in a drop tube furnace using flame monitoring techniques. Proc Combust Inst. 2015;35(3):3629–36.
Cai L, Zou C, Liu Y, Zhou K, Han Q, Zheng C. Numerical and experimental studies on the ignition of pulverized coal in O2/H2O atmospheres. Fuel. 2015;139:198–205.
Li Q, Zhao C, Chen X, Wu W, Li Y. Comparison of pulverized coal combustion in air and in O2/CO2 mixtures by thermo-gravimetric analysis. J Anal Appl Pyrolysis. 2009;85:521–8.
Wang C, Zhang X, Liu Y, Che D. Pyrolysis and combustion characteristics of coals in oxyfuel combustion. Appl Energy. 2012;97:264–73.
Xu Y, Zhang Y, Zhang G, Guo Y, Zhang J, Li G. Pyrolysis characteristics and kinetics of two Chinese low-rank coals. J Therm Anal Calorim. 2015;122(2):975–84.
Zhang Y, Zhang L, Duan F, Jiang X, Sun X, Chyang C. Co-combustion characteristics of sewage sludge with different rank bituminous coals under the O2/CO2 atmosphere. J Therm Anal Calorim. 2015;121(2):729–36.
Deng J, Wang K, Zhang Y, Yang H. Study on the kinetics and reactivity at the ignition temperature of Jurassic coal in North Shaanxi. J Therm Anal Calorim. 2014;118(1):417–23.
Flynn JH, Wall LA. A quick, direct method for the determination of activation energy from thermogravimetric data. J Polym Sci Part C Polym Lett. 1966;4:323–8.
Ozawa T. A new method of analyzing thermogravimetric data. Bull Chem Soc Jpn. 1965;38:1881–6.
Doyle CD. Estimating isothermal life from thermogravimetric data. J Appl Polym Sci. 1962;6:639–42.
Starink MJ. A new method for the derivation of activation energies from experiments performed at constant heating rate. Thermochim Acta. 1996;288:97–104.
Starink MJ. The determination of activation energy from linear heating rate experiments: a comparison of the accuracy of isoconversion methods. Thermochim Acta. 2003;404:163–76.
Starink MJ. Activation energy determination for linear heating experiments: deviations due to neglecting the low temperature end of the temperature integral. J Mater Sci. 2007;42:483–9.
Kissinger HE. Reaction kinetics in differential thermal analysis. Anal Chem. 1957;29:1702–6.
Popescu C. Integral method to analyze the kinetics of heterogeneous reactions under non-isothermal conditions a variant on the Ozawa–Flynn–Wall method. Thermochim Acta. 1996;285:309–23.
Zou C, Song Y, Li G, Cao S, He Y, Zheng C. The chemical mechanism of steam’s effect on the temperature in methane oxy-steam combustion. Int J Heat Mass Transf. 2014;75:12–8.
Liu H. Combustion of coal chars in O2/CO2 and O2/N2 mixtures: a comparative study with non-isothermal thermogravimetric analyzer (TGA) tests. Energy Fuels. 2009;23:4278–85.
Vyazovkin S, Wight CA. Model-free and model-fitting approaches to kinetic analysis of isothermal and nonisothermal data. Thermochim Acta. 1999;340–341:53–68.
Janković B, Mentus S, Jelić D. A kinetic study of non-isothermal decomposition process of anhydrous nickel nitrate under air atmosphere. Phys B. 2009;404:2263–9.
Galwey AK. Solid state decompositions: the interpretation of kinetic and microscopic data and the formulation of a reaction mechanism. Thermochim Acta. 1985;96:259–73.
Liu X, Li B, Miura K. Analysis of pyrolysis and gasification reactions of hydrothermally and supercritically upgraded low-rank coal by using a new distributed activation energy model. Fuel Process Technol. 2001;69:1–12.
Lunden M, Yang N, Headley T, Shaddix C, Hardesty D. Mineral matter effects on char structural evolution and oxidation kinetics during coal char combustion. Sandia National Labs, Albuquerque; 1997.
Zhang H, Li H, Chen J, Zhao B, Hu G. The influence of included minerals on the intrinsic reactivity of chars prepared under N2 and CO2 environment. In: Qi H, Zhao B, editors. Cleaner combustion and sustainable world. London: Springer; 2013. p. 1219–23.
Chan ML, Jones JM, Pourkashanian M, Williams A. The oxidative reactivity of coal chars in relation to their structure. Fuel. 1999;78:1539–52.
Wang B, Sun L, Su S, Xiang J, Hu S, Fei H. Char structural evolution during pyrolysis and its influence on combustion reactivity in air and oxy-fuel conditions. Energy Fuels. 2012;26:1565–74.
Wang C, Liu Y, Zhang X, Che D. A study on coal properties and combustion characteristics of blended coals in northwestern china. Energy Fuels. 2011;25:3634–45.
Lee DW, Bae JS, Park SJ, Lee YJ, Hong JC, Choi YC. The pore structure variation of coal char during pyrolysis and its relationship with char combustion reactivity. Ind Eng Chem Res. 2012;51:13580–8.
Hu RZ, Shi QZ. Thermal analysis kinetics. Beijing: Science Press; 2001. p. 127–31 (in Chinese).
Acknowledgements
This work was supported by the general program (51176055) of the National Natural Science Foundation of China and the National Key Basic Research and Development Program of China (Grant No. 2011CB707301). The authors gratefully thank the State Key Laboratory of Engines of Tianjin University.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Zhang, L., Zou, C., Wu, D. et al. A study of coal chars combustion in O2/H2O mixtures by thermogravimetric analysis. J Therm Anal Calorim 126, 995–1005 (2016). https://doi.org/10.1007/s10973-016-5536-1
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10973-016-5536-1